26763: fix problem on failed cd -s to relative path

[zsh.git] / Src / utils.c

/*
 * utils.c - miscellaneous utilities
 *
 * This file is part of zsh, the Z shell.
 *
 * Copyright (c) 1992-1997 Paul Falstad
 * All rights reserved.
 *
 * Permission is hereby granted, without written agreement and without
 * license or royalty fees, to use, copy, modify, and distribute this
 * software and to distribute modified versions of this software for any
 * purpose, provided that the above copyright notice and the following
 * two paragraphs appear in all copies of this software.
 *
 * In no event shall Paul Falstad or the Zsh Development Group be liable
 * to any party for direct, indirect, special, incidental, or consequential
 * damages arising out of the use of this software and its documentation,
 * even if Paul Falstad and the Zsh Development Group have been advised of
 * the possibility of such damage.
 *
 * Paul Falstad and the Zsh Development Group specifically disclaim any
 * warranties, including, but not limited to, the implied warranties of
 * merchantability and fitness for a particular purpose.  The software
 * provided hereunder is on an "as is" basis, and Paul Falstad and the
 * Zsh Development Group have no obligation to provide maintenance,
 * support, updates, enhancements, or modifications.
 *
 */

#include "zsh.mdh"
#include "utils.pro"

/* name of script being sourced */

/**/
mod_export char *scriptname;     /* is sometimes a function name */

/* filename of script or other file containing code source e.g. autoload */

/**/
mod_export char *scriptfilename;

#ifdef MULTIBYTE_SUPPORT
struct widechar_array {
    wchar_t *chars;
    size_t len;
};
typedef struct widechar_array *Widechar_array;

/*
 * The wordchars variable turned into a wide character array.
 * This is much more convenient for testing.
 */
struct widechar_array wordchars_wide;

/*
 * The same for the separators (IFS) array.
 */
struct widechar_array ifs_wide;

/* Function to set one of the above from the multibyte array */

static void
set_widearray(char *mb_array, Widechar_array wca)
{
    if (wca->chars) {
        free(wca->chars);
        wca->chars = NULL;
    }
    wca->len = 0;

    if (!isset(MULTIBYTE))
        return;

    if (mb_array) {
        VARARR(wchar_t, tmpwcs, strlen(mb_array));
        wchar_t *wcptr = tmpwcs;
        wint_t wci;

        mb_metacharinit();
        while (*mb_array) {
            int mblen = mb_metacharlenconv(mb_array, &wci);

            if (!mblen)
                break;
            /* No good unless all characters are convertible */
            if (wci == WEOF)
                return;
            *wcptr++ = (wchar_t)wci;
#ifdef DEBUG
            /*
             * This generates a warning from the compiler (and is
             * indeed useless) if chars are unsigned.  It's
             * extreme paranoia anyway.
             */
            if (wcptr[-1] < 0)
                fprintf(stderr, "BUG: Bad cast to wchar_t\n");
#endif
            mb_array += mblen;
        }

        wca->len = wcptr - tmpwcs;
        wca->chars = (wchar_t *)zalloc(wca->len * sizeof(wchar_t));
        wmemcpy(wca->chars, tmpwcs, wca->len);
    }
}
#endif


/* Print an error */

static void
zwarning(const char *cmd, const char *fmt, va_list ap)
{
    if (isatty(2))
        zleentry(ZLE_CMD_TRASH);

    if (cmd) {
        if (unset(SHINSTDIN) || locallevel) {
            nicezputs(scriptname ? scriptname : argzero, stderr);
            fputc((unsigned char)':', stderr);
        }
        nicezputs(cmd, stderr);
        fputc((unsigned char)':', stderr);
    } else {
        /*
         * scriptname is set when sourcing scripts, so that we get the
         * correct name instead of the generic name of whatever
         * program/script is running.  It's also set in shell functions,
         * so test locallevel, too.
         */
        nicezputs((isset(SHINSTDIN) && !locallevel) ? "zsh" :
                  scriptname ? scriptname : argzero, stderr);
        fputc((unsigned char)':', stderr);
    }

    zerrmsg(stderr, fmt, ap);
}


/**/
mod_export void
zerr(VA_ALIST1(const char *fmt))
VA_DCL
{
    va_list ap;
    VA_DEF_ARG(const char *fmt);

    if (errflag || noerrs) {
        if (noerrs < 2)
            errflag = 1;
        return;
    }

    VA_START(ap, fmt);
    VA_GET_ARG(ap, fmt, const char *);
    zwarning(NULL, fmt, ap);
    va_end(ap);
    errflag = 1;
}

/**/
mod_export void
zerrnam(VA_ALIST2(const char *cmd, const char *fmt))
VA_DCL
{
    va_list ap;
    VA_DEF_ARG(const char *cmd);
    VA_DEF_ARG(const char *fmt);

    if (errflag || noerrs)
        return;

    VA_START(ap, fmt);
    VA_GET_ARG(ap, cmd, const char *);
    VA_GET_ARG(ap, fmt, const char *);
    zwarning(cmd, fmt, ap);
    va_end(ap);
    errflag = 1;
}

/**/
mod_export void
zwarn(VA_ALIST1(const char *fmt))
VA_DCL
{
    va_list ap;
    VA_DEF_ARG(const char *fmt);

    if (errflag || noerrs)
        return;

    VA_START(ap, fmt);
    VA_GET_ARG(ap, fmt, const char *);
    zwarning(NULL, fmt, ap);
    va_end(ap);
}

/**/
mod_export void
zwarnnam(VA_ALIST2(const char *cmd, const char *fmt))
VA_DCL
{
    va_list ap;
    VA_DEF_ARG(const char *cmd);
    VA_DEF_ARG(const char *fmt);

    if (errflag || noerrs)
        return;

    VA_START(ap, fmt);
    VA_GET_ARG(ap, cmd, const char *);
    VA_GET_ARG(ap, fmt, const char *);
    zwarning(cmd, fmt, ap);
    va_end(ap);
}


#ifdef DEBUG

/**/
mod_export void
dputs(VA_ALIST1(const char *message))
VA_DCL
{
    char *filename;
    FILE *file;
    va_list ap;
    VA_DEF_ARG(const char *message);

    VA_START(ap, message);
    VA_GET_ARG(ap, message, const char *);
    if ((filename = getsparam("ZSH_DEBUG_LOG")) != NULL &&
        (file = fopen(filename, "a")) != NULL) {
        zerrmsg(file, message, ap);
        fclose(file);
    } else
        zerrmsg(stderr, message, ap);
    va_end(ap);
}

#endif /* DEBUG */

#ifdef __CYGWIN__
/*
 * This works around an occasional problem with dllwrap on Cygwin, seen
 * on at least two installations.  It fails to find the last symbol
 * exported in alphabetical order (in our case zwarnnam).  Until this is
 * properly categorised and fixed we add a dummy symbol at the end.
 */
mod_export void
zz_plural_z_alpha(void)
{
}
#endif

/**/
void
zerrmsg(FILE *file, const char *fmt, va_list ap)
{
    const char *str;
    int num;
#ifdef DEBUG
    long lnum;
#endif
#ifdef HAVE_STRERROR_R
#define ERRBUFSIZE (80)
    int olderrno;
    char errbuf[ERRBUFSIZE];
#endif
    char *errmsg;

    if ((unset(SHINSTDIN) || locallevel) && lineno)
        fprintf(file, "%ld: ", (long)lineno);
    else
        fputc((unsigned char)' ', file);

    while (*fmt)
        if (*fmt == '%') {
            fmt++;
            switch (*fmt++) {
            case 's':
                str = va_arg(ap, const char *);
                nicezputs(str, file);
                break;
            case 'l': {
                char *s;
                str = va_arg(ap, const char *);
                num = va_arg(ap, int);
                num = metalen(str, num);
                s = zhalloc(num + 1);
                memcpy(s, str, num);
                s[num] = '\0';
                nicezputs(s, file);
                break;
            }
#ifdef DEBUG
            case 'L':
                lnum = va_arg(ap, long);
                fprintf(file, "%ld", lnum);
                break;
#endif
            case 'd':
                num = va_arg(ap, int);
                fprintf(file, "%d", num);
                break;
            case '%':
                putc('%', file);
                break;
            case 'c':
                num = va_arg(ap, int);
#ifdef MULTIBYTE_SUPPORT
                mb_metacharinit();
                zputs(wcs_nicechar(num, NULL, NULL), file);
#else
                zputs(nicechar(num), file);
#endif
                break;
            case 'e':
                /* print the corresponding message for this errno */
                num = va_arg(ap, int);
                if (num == EINTR) {
                    fputs("interrupt\n", file);
                    errflag = 1;
                    return;
                }
                errmsg = strerror(num);
                /* If the message is not about I/O problems, it looks better *
                 * if we uncapitalize the first letter of the message        */
                if (num == EIO)
                    fputs(errmsg, file);
                else {
                    fputc(tulower(errmsg[0]), file);
                    fputs(errmsg + 1, file);
                }
                break;
            }
        } else {
            putc(*fmt == Meta ? *++fmt ^ 32 : *fmt, file);
            fmt++;
        }
    putc('\n', file);
    fflush(file);
}

/* Output a single character, for the termcap routines.     *
 * This is used instead of putchar since it can be a macro. */

/**/
mod_export int
putraw(int c)
{
    putc(c, stdout);
    return 0;
}

/* Output a single character, for the termcap routines. */

/**/
mod_export int
putshout(int c)
{
    putc(c, shout);
    return 0;
}

/*
 * Turn a character into a visible representation thereof.  The visible
 * string is put together in a static buffer, and this function returns
 * a pointer to it.  Printable characters stand for themselves, DEL is
 * represented as "^?", newline and tab are represented as "\n" and
 * "\t", and normal control characters are represented in "^C" form.
 * Characters with bit 7 set, if unprintable, are represented as "\M-"
 * followed by the visible representation of the character with bit 7
 * stripped off.  Tokens are interpreted, rather than being treated as
 * literal characters.
 *
 * Note that the returned string is metafied, so that it must be
 * treated like any other zsh internal string (and not, for example,
 * output directly).
 *
 * This function is used even if MULTIBYTE_SUPPORT is defined: we
 * use it as a fallback in case we couldn't identify a wide character
 * in a multibyte string.
 */

/**/
mod_export char *
nicechar(int c)
{
    static char buf[6];
    char *s = buf;
    c &= 0xff;
    if (isprint(c))
        goto done;
    if (c & 0x80) {
        if (isset(PRINTEIGHTBIT))
            goto done;
        *s++ = '\\';
        *s++ = 'M';
        *s++ = '-';
        c &= 0x7f;
        if(isprint(c))
            goto done;
    }
    if (c == 0x7f) {
        *s++ = '^';
        c = '?';
    } else if (c == '\n') {
        *s++ = '\\';
        c = 'n';
    } else if (c == '\t') {
        *s++ = '\\';
        c = 't';
    } else if (c < 0x20) {
        *s++ = '^';
        c += 0x40;
    }
    done:
    /*
     * The resulting string is still metafied, so check if
     * we are returning a character in the range that needs metafication.
     * This can't happen if the character is printed "nicely", so
     * this results in a maximum of two bytes total (plus the null).
     */
    if (imeta(c)) {
        *s++ = Meta;
        *s++ = c ^ 32;
    } else
        *s++ = c;
    *s = 0;
    return buf;
}

/**/
#ifdef MULTIBYTE_SUPPORT
static mbstate_t mb_shiftstate;

/*
 * Initialise multibyte state: called before a sequence of
 * wcs_nicechar() or mb_metacharlenconv().
 */

/**/
mod_export void
mb_metacharinit(void)
{
    memset(&mb_shiftstate, 0, sizeof(mb_shiftstate));
}

/*
 * The number of bytes we need to allocate for a "nice" representation
 * of a multibyte character.
 *
 * We double MB_CUR_MAX to take account of the fact that
 * we may need to metafy.  In fact the representation probably
 * doesn't allow every character to be in the meta range, but
 * we don't need to be too pedantic.
 *
 * The 12 is for the output of a UCS-4 code; we don't actually
 * need this at the same time as MB_CUR_MAX, but again it's
 * not worth calculating more exactly.
 */
#define NICECHAR_MAX (12 + 2*MB_CUR_MAX)
/*
 * Input a wide character.  Output a printable representation,
 * which is a metafied multibyte string.   With widthp return
 * the printing width.
 *
 * swide, if non-NULL, is used to help the completion code, which needs
 * to know the printing width of the each part of the representation.
 * *swide is set to the part of the returned string where the wide
 * character starts.  Any string up to that point is ASCII characters,
 * so the width of it is (*swide - <return_value>).  Anything left is
 * a single wide character corresponding to the remaining width.
 * Either the initial ASCII part or the wide character part may be empty
 * (but not both).  (Note the complication that the wide character
 * part may contain metafied characters.)
 *
 * The caller needs to call mb_metacharinit() before the first call, to
 * set up the multibyte shift state for a range of characters.
 */

/**/
mod_export char *
wcs_nicechar(wchar_t c, size_t *widthp, char **swidep)
{
    static char *buf;
    static int bufalloc = 0, newalloc;
    char *s, *mbptr;
    int ret = 0;
    VARARR(char, mbstr, MB_CUR_MAX);

    /*
     * We want buf to persist beyond the return.  MB_CUR_MAX and hence
     * NICECHAR_MAX may not be constant, so we have to allocate this at
     * run time.  (We could probably get away with just allocating a
     * large buffer, in practice.)  For efficiency, only reallocate if
     * we really need to, since this function will be called frequently.
     */
    newalloc = NICECHAR_MAX;
    if (bufalloc != newalloc)
    {
        bufalloc = newalloc;
        buf = (char *)zrealloc(buf, bufalloc);
    }

    s = buf;
    if (!iswprint(c) && (c < 0x80 || !isset(PRINTEIGHTBIT))) {
        if (c == 0x7f) {
            *s++ = '^';
            c = '?';
        } else if (c == L'\n') {
            *s++ = '\\';
            c = 'n';
        } else if (c == L'\t') {
            *s++ = '\\';
            c = 't';
        } else if (c < 0x20) {
            *s++ = '^';
            c += 0x40;
        } else if (c >= 0x80) {
            ret = -1;
        }
    }

    if (ret != -1)
        ret = wcrtomb(mbstr, c, &mb_shiftstate);

    if (ret == -1) {
        memset(&mb_shiftstate, 0, sizeof(mb_shiftstate));
        /*
         * Can't or don't want to convert character: use UCS-2 or
         * UCS-4 code in print escape format.
         *
         * This comparison fails and generates a compiler warning
         * if wchar_t is 16 bits, but the code is still correct.
         */
        if (c >=  0x10000) {
            sprintf(buf, "\\U%.8x", (unsigned int)c);
            if (widthp)
                *widthp = 10;
        } else if (c >= 0x100) {
            sprintf(buf, "\\u%.4x", (unsigned int)c);
            if (widthp)
                *widthp = 6;
        } else {
            strcpy(buf, nicechar((int)c));
            /*
             * There may be metafied characters from nicechar(),
             * so compute width and end position independently.
             */
            if (widthp)
                *widthp = ztrlen(buf);
            if (swidep)
              *swidep = buf + strlen(buf);
            return buf;
        }
        if (swidep)
            *swidep = buf + *widthp;
        return buf;
    }

    if (widthp) {
        int wcw = WCWIDTH(c);
        *widthp = (s - buf);
        if (wcw >= 0)
            *widthp += wcw;
        else
            (*widthp)++;
    }
    if (swidep)
        *swidep = s;
    for (mbptr = mbstr; ret; s++, mbptr++, ret--) {
        DPUTS(s >= buf + NICECHAR_MAX,
              "BUG: buffer too small in wcs_nicechar");
        if (imeta(*mbptr)) {
            *s++ = Meta;
            DPUTS(s >= buf + NICECHAR_MAX,
                  "BUG: buffer too small for metafied char in wcs_nicechar");
            *s = *mbptr ^ 32;
        } else {
            *s = *mbptr;
        }
    }
    *s = 0;
    return buf;
}

/**/
mod_export int
zwcwidth(wint_t wc)
{
    int wcw;
    /* assume a single-byte character if not valid */
    if (wc == WEOF || unset(MULTIBYTE))
        return 1;
    wcw = WCWIDTH(wc);
    /* if not printable, assume width 1 */
    if (wcw < 0)
        return 1;
    return wcw;
}

/**/
#endif /* MULTIBYTE_SUPPORT */

/* get a symlink-free pathname for s relative to PWD */

/**/
char *
findpwd(char *s)
{
    char *t;

    if (*s == '/')
        return xsymlink(s);
    s = tricat((pwd[1]) ? pwd : "", "/", s);
    t = xsymlink(s);
    zsfree(s);
    return t;
}

/* Check whether a string contains the *
 * name of the present directory.      */

/**/
int
ispwd(char *s)
{
    struct stat sbuf, tbuf;

    if (stat(unmeta(s), &sbuf) == 0 && stat(".", &tbuf) == 0)
        if (sbuf.st_dev == tbuf.st_dev && sbuf.st_ino == tbuf.st_ino)
            return 1;
    return 0;
}

static char xbuf[PATH_MAX*2];

/**/
static char **
slashsplit(char *s)
{
    char *t, **r, **q;
    int t0;

    if (!*s)
        return (char **) zshcalloc(sizeof(char **));

    for (t = s, t0 = 0; *t; t++)
        if (*t == '/')
            t0++;
    q = r = (char **) zalloc(sizeof(char **) * (t0 + 2));

    while ((t = strchr(s, '/'))) {
        *q++ = ztrduppfx(s, t - s);
        while (*t == '/')
            t++;
        if (!*t) {
            *q = NULL;
            return r;
        }
        s = t;
    }
    *q++ = ztrdup(s);
    *q = NULL;
    return r;
}

/* expands symlinks and .. or . expressions */
/* if flag = 0, only expand .. and . expressions */

/**/
static int
xsymlinks(char *s)
{
    char **pp, **opp;
    char xbuf2[PATH_MAX*2], xbuf3[PATH_MAX*2];
    int t0, ret = 0;

    opp = pp = slashsplit(s);
    for (; *pp; pp++) {
        if (!strcmp(*pp, ".")) {
            zsfree(*pp);
            continue;
        }
        if (!strcmp(*pp, "..")) {
            char *p;

            zsfree(*pp);
            if (!strcmp(xbuf, "/"))
                continue;
            p = xbuf + strlen(xbuf);
            while (*--p != '/');
            *p = '\0';
            continue;
        }
        sprintf(xbuf2, "%s/%s", xbuf, *pp);
        t0 = readlink(unmeta(xbuf2), xbuf3, PATH_MAX);
        if (t0 == -1) {
            strcat(xbuf, "/");
            strcat(xbuf, *pp);
            zsfree(*pp);
        } else {
            ret = 1;
            metafy(xbuf3, t0, META_NOALLOC);
            if (*xbuf3 == '/') {
                strcpy(xbuf, "");
                xsymlinks(xbuf3 + 1);
            } else
                xsymlinks(xbuf3);
            zsfree(*pp);
        }
    }
    free(opp);
    return ret;
}

/*
 * expand symlinks in s, and remove other weird things:
 * note that this always expands symlinks.
 */

/**/
char *
xsymlink(char *s)
{
    if (*s != '/')
        return NULL;
    *xbuf = '\0';
    xsymlinks(s + 1);
    if (!*xbuf)
        return ztrdup("/");
    return ztrdup(xbuf);
}

/**/
void
print_if_link(char *s)
{
    if (*s == '/') {
        *xbuf = '\0';
        if (xsymlinks(s + 1))
            printf(" -> "), zputs(*xbuf ? xbuf : "/", stdout);
    }
}

/* print a directory */

/**/
void
fprintdir(char *s, FILE *f)
{
    Nameddir d = finddir(s);

    if (!d)
        fputs(unmeta(s), f);
    else {
        putc('~', f);
        fputs(unmeta(d->node.nam), f);
        fputs(unmeta(s + strlen(d->dir)), f);
    }
}

/* Returns the current username.  It caches the username *
 * and uid to try to avoid requerying the password files *
 * or NIS/NIS+ database.                                 */

/**/
uid_t cached_uid;
/**/
char *cached_username;

/**/
char *
get_username(void)
{
#ifdef HAVE_GETPWUID
    struct passwd *pswd;
    uid_t current_uid;

    current_uid = getuid();
    if (current_uid != cached_uid) {
        cached_uid = current_uid;
        zsfree(cached_username);
        if ((pswd = getpwuid(current_uid)))
            cached_username = ztrdup(pswd->pw_name);
        else
            cached_username = ztrdup("");
    }
#else /* !HAVE_GETPWUID */
    cached_uid = getuid();
#endif /* !HAVE_GETPWUID */
    return cached_username;
}

/* static variables needed by finddir(). */

static char *finddir_full;
static Nameddir finddir_last;
static int finddir_best;

/* ScanFunc used by finddir(). */

/**/
static void
finddir_scan(HashNode hn, UNUSED(int flags))
{
    Nameddir nd = (Nameddir) hn;

    if(nd->diff > finddir_best && !dircmp(nd->dir, finddir_full)
       && !(nd->node.flags & ND_NOABBREV)) {
        finddir_last=nd;
        finddir_best=nd->diff;
    }
}

/* See if a path has a named directory as its prefix. *
 * If passed a NULL argument, it will invalidate any  *
 * cached information.                                */

/**/
Nameddir
finddir(char *s)
{
    static struct nameddir homenode = { {NULL, "", 0}, NULL, 0 };
    static int ffsz;
    Shfunc func = getshfunc("zsh_directory_name");

    /* Invalidate directory cache if argument is NULL.  This is called *
     * whenever a node is added to or removed from the hash table, and *
     * whenever the value of $HOME changes.  (On startup, too.)        */
    if (!s) {
        homenode.dir = home ? home : "";
        homenode.diff = home ? strlen(home) : 0;
        if(homenode.diff==1)
            homenode.diff = 0;
        if(!finddir_full)
            finddir_full = zalloc(ffsz = PATH_MAX);
        finddir_full[0] = 0;
        return finddir_last = NULL;
    }

    /* It's not safe to use the cache while we have function transformations.*/
    if(!func && !strcmp(s, finddir_full) && *finddir_full)
        return finddir_last;

    if ((int)strlen(s) >= ffsz) {
        free(finddir_full);
        finddir_full = zalloc(ffsz = strlen(s) * 2);
    }
    strcpy(finddir_full, s);
    finddir_best=0;
    finddir_last=NULL;
    finddir_scan(&homenode.node, 0);
    scanhashtable(nameddirtab, 0, 0, 0, finddir_scan, 0);

    if (func) {
        char *dir_meta = metafy(finddir_full, strlen(finddir_full),
                                META_ALLOC);
        char **ares = subst_string_by_func(func, "d", dir_meta);
        int len;
        if (ares && arrlen(ares) >= 2 &&
            (len = (int)zstrtol(ares[1], NULL, 10)) > finddir_best) {
            /* better duplicate this string since it's come from REPLY */
            finddir_last = (Nameddir)hcalloc(sizeof(struct nameddir));
            finddir_last->node.nam = zhtricat("[", dupstring(ares[0]), "]");
            finddir_last->dir = dupstrpfx(finddir_full, len);
            finddir_last->diff = len - strlen(finddir_last->node.nam);
            finddir_best = len;
        }
        if (dir_meta != finddir_full)
            zsfree(dir_meta);
    }

    return finddir_last;
}

/* add a named directory */

/**/
mod_export void
adduserdir(char *s, char *t, int flags, int always)
{
    Nameddir nd;
    char *eptr;

    /* We don't maintain a hash table in non-interactive shells. */
    if (!interact)
        return;

    /* The ND_USERNAME flag means that this possible hash table *
     * entry is derived from a passwd entry.  Such entries are  *
     * subordinate to explicitly generated entries.             */
    if ((flags & ND_USERNAME) && nameddirtab->getnode2(nameddirtab, s))
        return;

    /* Normal parameter assignments generate calls to this function, *
     * with always==0.  Unless the AUTO_NAME_DIRS option is set, we  *
     * don't let such assignments actually create directory names.   *
     * Instead, a reference to the parameter as a directory name can *
     * cause the actual creation of the hash table entry.            */
    if (!always && unset(AUTONAMEDIRS) &&
            !nameddirtab->getnode2(nameddirtab, s))
        return;

    if (!t || *t != '/' || strlen(t) >= PATH_MAX) {
        /* We can't use this value as a directory, so simply remove *
         * the corresponding entry in the hash table, if any.       */
        HashNode hn = nameddirtab->removenode(nameddirtab, s);

        if(hn)
            nameddirtab->freenode(hn);
        return;
    }

    /* add the name */
    nd = (Nameddir) zshcalloc(sizeof *nd);
    nd->node.flags = flags;
    eptr = t + strlen(t);
    while (eptr > t && eptr[-1] == '/')
        eptr--;
    if (eptr == t) {
        /*
         * Don't abbreviate multiple slashes at the start of a
         * named directory, since these are sometimes used for
         * special purposes.
         */
        nd->dir = ztrdup(t);
    } else
        nd->dir = ztrduppfx(t, eptr - t);
    /* The variables PWD and OLDPWD are not to be displayed as ~PWD etc. */
    if (!strcmp(s, "PWD") || !strcmp(s, "OLDPWD"))
        nd->node.flags |= ND_NOABBREV;
    nameddirtab->addnode(nameddirtab, ztrdup(s), nd);
}

/* Get a named directory: this function can cause a directory name *
 * to be added to the hash table, if it isn't there already.       */

/**/
char *
getnameddir(char *name)
{
    Param pm;
    char *str;
    Nameddir nd;

    /* Check if it is already in the named directory table */
    if ((nd = (Nameddir) nameddirtab->getnode(nameddirtab, name)))
        return dupstring(nd->dir);

    /* Check if there is a scalar parameter with this name whose value *
     * begins with a `/'.  If there is, add it to the hash table and   *
     * return the new value.                                           */
    if ((pm = (Param) paramtab->getnode(paramtab, name)) &&
            (PM_TYPE(pm->node.flags) == PM_SCALAR) &&
            (str = getsparam(name)) && *str == '/') {
        pm->node.flags |= PM_NAMEDDIR;
        adduserdir(name, str, 0, 1);
        return str;
    }

#ifdef HAVE_GETPWNAM
    {
        /* Retrieve an entry from the password table/database for this user. */
        struct passwd *pw;
        if ((pw = getpwnam(name))) {
            char *dir = isset(CHASELINKS) ? xsymlink(pw->pw_dir)
                : ztrdup(pw->pw_dir);
            adduserdir(name, dir, ND_USERNAME, 1);
            str = dupstring(dir);
            zsfree(dir);
            return str;
        }
    }
#endif /* HAVE_GETPWNAM */

    /* There are no more possible sources of directory names, so give up. */
    return NULL;
}

/**/
static int
dircmp(char *s, char *t)
{
    if (s) {
        for (; *s == *t; s++, t++)
            if (!*s)
                return 0;
        if (!*s && *t == '/')
            return 0;
    }
    return 1;
}

/*
 * Extra functions to call before displaying the prompt.
 * The data is a Prepromptfn.
 */

static LinkList prepromptfns;

/* Add a function to the list of pre-prompt functions. */

/**/
mod_export void
addprepromptfn(voidvoidfnptr_t func)
{
    Prepromptfn ppdat = (Prepromptfn)zalloc(sizeof(struct prepromptfn));
    ppdat->func = func;
    if (!prepromptfns)
        prepromptfns = znewlinklist();
    zaddlinknode(prepromptfns, ppdat);
}

/* Remove a function from the list of pre-prompt functions. */

/**/
mod_export void
delprepromptfn(voidvoidfnptr_t func)
{
    LinkNode ln;

    for (ln = firstnode(prepromptfns); ln; ln = nextnode(ln)) {
        Prepromptfn ppdat = (Prepromptfn)getdata(ln);
        if (ppdat->func == func) {
            (void)remnode(prepromptfns, ln);
            zfree(ppdat, sizeof(struct prepromptfn));
            return;
        }
    }
#ifdef DEBUG
    dputs("BUG: failed to delete node from prepromptfns");
#endif
}

/*
 * Functions to call at a particular time even if not at
 * the prompt.  This is handled by zle.  The data is a
 * Timedfn.  The functions must be in time order, but this
 * is enforced by addtimedfn().
 *
 * Note on debugging:  the code in sched.c currently assumes it's
 * the only user of timedfns for the purposes of checking whether
 * there's a function on the list.  If this becomes no longer the case,
 * the DPUTS() tests in sched.c need rewriting.
 */

/**/
mod_export LinkList timedfns;

/* Add a function to the list of timed functions. */

/**/
mod_export void
addtimedfn(voidvoidfnptr_t func, time_t when)
{
    Timedfn tfdat = (Timedfn)zalloc(sizeof(struct timedfn));
    tfdat->func = func;
    tfdat->when = when;

    if (!timedfns) {
        timedfns = znewlinklist();
        zaddlinknode(timedfns, tfdat);
    } else {
        LinkNode ln = firstnode(timedfns);

        /*
         * Insert the new element in the linked list.  We do
         * rather too much work here since the standard
         * functions insert after a given node, whereas we
         * want to insert the new data before the first element
         * with a greater time.
         *
         * In practice, the only use of timed functions is
         * sched, which only adds the one function; so this
         * whole branch isn't used beyond the following block.
         */
        if (!ln) {
            zaddlinknode(timedfns, tfdat);
            return;
        }
        for (;;) {
            Timedfn tfdat2;
            LinkNode next = nextnode(ln);
            if (!next) {
                zaddlinknode(timedfns, tfdat);
                return;
            }
            tfdat2 = (Timedfn)getdata(next);
            if (when < tfdat2->when) {
                zinsertlinknode(timedfns, ln, tfdat);
                return;
            }
            ln = next;
        }
    }
}

/*
 * Delete a function from the list of timed functions.
 * Note that if the function apperas multiple times only
 * the first occurrence will be removed.
 *
 * Note also that when zle calls the function it does *not*
 * automatically delete the entry from the list.  That must
 * be done by the function called.  This is recommended as otherwise
 * the function will keep being called immediately.  (It just so
 * happens this "feature" fits in well with the only current use
 * of timed functions.)
 */

/**/
mod_export void
deltimedfn(voidvoidfnptr_t func)
{
    LinkNode ln;

    for (ln = firstnode(timedfns); ln; ln = nextnode(ln)) {
        Timedfn ppdat = (Timedfn)getdata(ln);
        if (ppdat->func == func) {
            (void)remnode(timedfns, ln);
            zfree(ppdat, sizeof(struct timedfn));
            return;
        }
    }
#ifdef DEBUG
    dputs("BUG: failed to delete node from timedfns");
#endif
}

/* the last time we checked mail */

/**/
time_t lastmailcheck;

/* the last time we checked the people in the WATCH variable */

/**/
time_t lastwatch;

/*
 * Call a function given by "name" with optional arguments
 * "lnklist".  If these are present the first argument is the function name.
 *
 * If "arrayp" is not zero, we also look through
 * the array "name"_functions and execute functions found there.
 *
 * If "retval" is not NULL, the return value of the first hook function to
 * return non-zero is stored in *"retval".  The return value is not otherwise
 * available as the calling context is restored.
 */

/**/
mod_export int
callhookfunc(char *name, LinkList lnklst, int arrayp, int *retval)
{
    Shfunc shfunc;
        /*
         * Save stopmsg, since user doesn't get a chance to respond
         * to a list of jobs generated in a hook.
         */
    int osc = sfcontext, osm = stopmsg, stat = 1, ret = 0;

    sfcontext = SFC_HOOK;

    if ((shfunc = getshfunc(name))) {
        ret = doshfunc(shfunc, lnklst, 1);
        stat = 0;
    }

    if (arrayp) {
        char **arrptr;
        int namlen = strlen(name);
        VARARR(char, arrnam, namlen + HOOK_SUFFIX_LEN);
        memcpy(arrnam, name, namlen);
        memcpy(arrnam + namlen, HOOK_SUFFIX, HOOK_SUFFIX_LEN);

        if ((arrptr = getaparam(arrnam))) {
            for (; *arrptr; arrptr++) {
                if ((shfunc = getshfunc(*arrptr))) {
                    int newret = doshfunc(shfunc, lnklst, 1);
                    if (!ret)
                        ret = newret;
                    stat = 0;
                }
            }
        }
    }

    sfcontext = osc;
    stopmsg = osm;

    if (retval)
        *retval = ret;
    return stat;
}

/* do pre-prompt stuff */

/**/
void
preprompt(void)
{
    static time_t lastperiodic;
    LinkNode ln;
    int period = getiparam("PERIOD");
    int mailcheck = getiparam("MAILCHECK");

    if (isset(PROMPTSP) && isset(PROMPTCR) && !use_exit_printed && shout) {
        /* The PROMPT_SP heuristic will move the prompt down to a new line
         * if there was any dangling output on the line (assuming the terminal
         * has automatic margins, but we try even if hasam isn't set).
         * Unfortunately it interacts badly with ZLE displaying message
         * when ^D has been pressed. So just disable PROMPT_SP logic in
         * this case */
        char *str;
        int percents = opts[PROMPTPERCENT];
        opts[PROMPTPERCENT] = 1;
        str = promptexpand("%B%S%#%s%b", 0, NULL, NULL, NULL);
        opts[PROMPTPERCENT] = percents;
        fprintf(shout, "%s%*s\r", str, (int)columns - 1 - !hasxn, "");
        free(str);
    }

    /* If NOTIFY is not set, then check for completed *
     * jobs before we print the prompt.               */
    if (unset(NOTIFY))
        scanjobs();
    if (errflag)
        return;

    /* If a shell function named "precmd" exists, *
     * then execute it.                           */
    callhookfunc("precmd", NULL, 1, NULL);
    if (errflag)
        return;

    /* If 1) the parameter PERIOD exists, 2) a hook function for    *
     * "periodic" exists, 3) it's been greater than PERIOD since we *
     * executed any such hook, then execute it now.                 */
    if (period && (time(NULL) > lastperiodic + period) &&
        !callhookfunc("periodic", NULL, 1, NULL))
        lastperiodic = time(NULL);
    if (errflag)
        return;

    /* If WATCH is set, then check for the *
     * specified login/logout events.      */
    if (watch) {
        if ((int) difftime(time(NULL), lastwatch) > getiparam("LOGCHECK")) {
            dowatch();
            lastwatch = time(NULL);
        }
    }
    if (errflag)
        return;

    /* Check mail */
    if (mailcheck && (int) difftime(time(NULL), lastmailcheck) > mailcheck) {
        char *mailfile;

        if (mailpath && *mailpath && **mailpath)
            checkmailpath(mailpath);
        else {
            queue_signals();
            if ((mailfile = getsparam("MAIL")) && *mailfile) {
                char *x[2];

                x[0] = mailfile;
                x[1] = NULL;
                checkmailpath(x);
            }
            unqueue_signals();
        }
        lastmailcheck = time(NULL);
    }

    if (prepromptfns) {
        for(ln = firstnode(prepromptfns); ln; ln = nextnode(ln)) {
            Prepromptfn ppnode = (Prepromptfn)getdata(ln);
            ppnode->func();
        }
    }
}

/**/
static void
checkmailpath(char **s)
{
    struct stat st;
    char *v, *u, c;

    while (*s) {
        for (v = *s; *v && *v != '?'; v++);
        c = *v;
        *v = '\0';
        if (c != '?')
            u = NULL;
        else
            u = v + 1;
        if (**s == 0) {
            *v = c;
            zerr("empty MAILPATH component: %s", *s);
        } else if (mailstat(unmeta(*s), &st) == -1) {
            if (errno != ENOENT)
                zerr("%e: %s", errno, *s);
        } else if (S_ISDIR(st.st_mode)) {
            LinkList l;
            DIR *lock = opendir(unmeta(*s));
            char buf[PATH_MAX * 2], **arr, **ap;
            int ct = 1;

            if (lock) {
                char *fn;

                pushheap();
                l = newlinklist();
                while ((fn = zreaddir(lock, 1)) && !errflag) {
                    if (u)
                        sprintf(buf, "%s/%s?%s", *s, fn, u);
                    else
                        sprintf(buf, "%s/%s", *s, fn);
                    addlinknode(l, dupstring(buf));
                    ct++;
                }
                closedir(lock);
                ap = arr = (char **) zhalloc(ct * sizeof(char *));

                while ((*ap++ = (char *)ugetnode(l)));
                checkmailpath(arr);
                popheap();
            }
        } else if (shout) {
            if (st.st_size && st.st_atime <= st.st_mtime &&
                st.st_mtime > lastmailcheck) {
                if (!u) {
                    fprintf(shout, "You have new mail.\n");
                    fflush(shout);
                } else {
                    char *usav;
                    int uusav = underscoreused;

                    usav = zalloc(underscoreused);

                    if (usav)
                        memcpy(usav, underscore, underscoreused);

                    setunderscore(*s);

                    u = dupstring(u);
                    if (! parsestr(u)) {
                        singsub(&u);
                        zputs(u, shout);
                        fputc('\n', shout);
                        fflush(shout);
                    }
                    if (usav) {
                        setunderscore(usav);
                        zfree(usav, uusav);
                    }
                }
            }
            if (isset(MAILWARNING) && st.st_atime > st.st_mtime &&
                st.st_atime > lastmailcheck && st.st_size) {
                fprintf(shout, "The mail in %s has been read.\n", unmeta(*s));
                fflush(shout);
            }
        }
        *v = c;
        s++;
    }
}

/* This prints the XTRACE prompt. */

/**/
FILE *xtrerr = 0;

/**/
void
printprompt4(void)
{
    if (!xtrerr)
        xtrerr = stderr;
    if (prompt4) {
        int l, t = opts[XTRACE];
        char *s = dupstring(prompt4);

        opts[XTRACE] = 0;
        unmetafy(s, &l);
        s = unmetafy(promptexpand(metafy(s, l, META_NOALLOC),
                                  0, NULL, NULL, NULL), &l);
        opts[XTRACE] = t;

        fprintf(xtrerr, "%s", s);
        free(s);
    }
}

/**/
mod_export void
freestr(void *a)
{
    zsfree(a);
}

/**/
mod_export void
gettyinfo(struct ttyinfo *ti)
{
    if (SHTTY != -1) {
#ifdef HAVE_TERMIOS_H
# ifdef HAVE_TCGETATTR
        if (tcgetattr(SHTTY, &ti->tio) == -1)
# else
        if (ioctl(SHTTY, TCGETS, &ti->tio) == -1)
# endif
            zerr("bad tcgets: %e", errno);
#else
# ifdef HAVE_TERMIO_H
        ioctl(SHTTY, TCGETA, &ti->tio);
# else
        ioctl(SHTTY, TIOCGETP, &ti->sgttyb);
        ioctl(SHTTY, TIOCLGET, &ti->lmodes);
        ioctl(SHTTY, TIOCGETC, &ti->tchars);
        ioctl(SHTTY, TIOCGLTC, &ti->ltchars);
# endif
#endif
    }
}

/**/
mod_export void
settyinfo(struct ttyinfo *ti)
{
    if (SHTTY != -1) {
#ifdef HAVE_TERMIOS_H
# ifdef HAVE_TCGETATTR
#  ifndef TCSADRAIN
#   define TCSADRAIN 1  /* XXX Princeton's include files are screwed up */
#  endif
        while (tcsetattr(SHTTY, TCSADRAIN, &ti->tio) == -1 && errno == EINTR)
            ;
# else
        while (ioctl(SHTTY, TCSETS, &ti->tio) == -1 && errno == EINTR)
            ;
# endif
        /*      zerr("settyinfo: %e",errno);*/
#else
# ifdef HAVE_TERMIO_H
        ioctl(SHTTY, TCSETA, &ti->tio);
# else
        ioctl(SHTTY, TIOCSETN, &ti->sgttyb);
        ioctl(SHTTY, TIOCLSET, &ti->lmodes);
        ioctl(SHTTY, TIOCSETC, &ti->tchars);
        ioctl(SHTTY, TIOCSLTC, &ti->ltchars);
# endif
#endif
    }
}

/* the default tty state */

/**/
mod_export struct ttyinfo shttyinfo;

/* != 0 if we need to call resetvideo() */

/**/
mod_export int resetneeded;

#ifdef TIOCGWINSZ
/* window size changed */

/**/
mod_export int winchanged;
#endif

static int
adjustlines(int signalled)
{
    int oldlines = lines;

#ifdef TIOCGWINSZ
    if (signalled || lines <= 0)
        lines = shttyinfo.winsize.ws_row;
    else
        shttyinfo.winsize.ws_row = lines;
#endif /* TIOCGWINSZ */
    if (lines <= 0) {
        DPUTS(signalled, "BUG: Impossible TIOCGWINSZ rows");
        lines = tclines > 0 ? tclines : 24;
    }

    if (lines > 2)
        termflags &= ~TERM_SHORT;
    else
        termflags |= TERM_SHORT;

    return (lines != oldlines);
}

static int
adjustcolumns(int signalled)
{
    int oldcolumns = columns;

#ifdef TIOCGWINSZ
    if (signalled || columns <= 0)
        columns = shttyinfo.winsize.ws_col;
    else
        shttyinfo.winsize.ws_col = columns;
#endif /* TIOCGWINSZ */
    if (columns <= 0) {
        DPUTS(signalled, "BUG: Impossible TIOCGWINSZ cols");
        columns = tccolumns > 0 ? tccolumns : 80;
    }

    if (columns > 2)
        termflags &= ~TERM_NARROW;
    else
        termflags |= TERM_NARROW;

    return (columns != oldcolumns);
}

/* check the size of the window and adjust if necessary. *
 * The value of from:                                    *
 *   0: called from update_job or setupvals              *
 *   1: called from the SIGWINCH handler                 *
 *   2: called from the LINES parameter callback         *
 *   3: called from the COLUMNS parameter callback       */

/**/
void
adjustwinsize(int from)
{
    static int getwinsz = 1;
#ifdef TIOCGWINSZ
    int ttyrows = shttyinfo.winsize.ws_row;
    int ttycols = shttyinfo.winsize.ws_col;
#endif
    int resetzle = 0;

    if (getwinsz || from == 1) {
#ifdef TIOCGWINSZ
        if (SHTTY == -1)
            return;
        if (ioctl(SHTTY, TIOCGWINSZ, (char *)&shttyinfo.winsize) == 0) {
            resetzle = (ttyrows != shttyinfo.winsize.ws_row ||
                        ttycols != shttyinfo.winsize.ws_col);
            if (from == 0 && resetzle && ttyrows && ttycols)
                from = 1; /* Signal missed while a job owned the tty? */
            ttyrows = shttyinfo.winsize.ws_row;
            ttycols = shttyinfo.winsize.ws_col;
        } else {
            /* Set to value from environment on failure */
            shttyinfo.winsize.ws_row = lines;
            shttyinfo.winsize.ws_col = columns;
            resetzle = (from == 1);
        }
#else
        resetzle = from == 1;
#endif /* TIOCGWINSZ */
    } /* else
         return; */

    switch (from) {
    case 0:
    case 1:
        getwinsz = 0;
        /* Calling setiparam() here calls this function recursively, but  *
         * because we've already called adjustlines() and adjustcolumns() *
         * here, recursive calls are no-ops unless a signal intervenes.   *
         * The commented "else return;" above might be a safe shortcut,   *
         * but I'm concerned about what happens on race conditions; e.g., *
         * suppose the user resizes his xterm during `eval $(resize)'?    */
        if (adjustlines(from) && zgetenv("LINES"))
            setiparam("LINES", lines);
        if (adjustcolumns(from) && zgetenv("COLUMNS"))
            setiparam("COLUMNS", columns);
        getwinsz = 1;
        break;
    case 2:
        resetzle = adjustlines(0);
        break;
    case 3:
        resetzle = adjustcolumns(0);
        break;
    }

#ifdef TIOCGWINSZ
    if (interact && from >= 2 &&
        (shttyinfo.winsize.ws_row != ttyrows ||
         shttyinfo.winsize.ws_col != ttycols)) {
        /* shttyinfo.winsize is already set up correctly */
        ioctl(SHTTY, TIOCSWINSZ, (char *)&shttyinfo.winsize);
    }
#endif /* TIOCGWINSZ */

    if (zleactive && resetzle) {
#ifdef TIOCGWINSZ
        winchanged =
#endif /* TIOCGWINSZ */
            resetneeded = 1;
        zleentry(ZLE_CMD_REFRESH);
        zleentry(ZLE_CMD_RESET_PROMPT);
    }
}

/* Move a fd to a place >= 10 and mark the new fd in fdtable.  If the fd *
 * is already >= 10, it is not moved.  If it is invalid, -1 is returned. */

/**/
mod_export int
movefd(int fd)
{
    if(fd != -1 && fd < 10) {
#ifdef F_DUPFD
        int fe = fcntl(fd, F_DUPFD, 10);
#else
        int fe = movefd(dup(fd));
#endif
        zclose(fd);
        fd = fe;
    }
    if(fd != -1) {
        if (fd > max_zsh_fd) {
            while (fd >= fdtable_size)
                fdtable = zrealloc(fdtable,
                                   (fdtable_size *= 2)*sizeof(*fdtable));
            max_zsh_fd = fd;
        }
        fdtable[fd] = FDT_INTERNAL;
    }
    return fd;
}

/* Move fd x to y.  If x == -1, fd y is closed. */

/**/
mod_export void
redup(int x, int y)
{
    if(x < 0)
        zclose(y);
    else if (x != y) {
        while (y >= fdtable_size)
            fdtable = zrealloc(fdtable, (fdtable_size *= 2)*sizeof(*fdtable));
        dup2(x, y);
        if ((fdtable[y] = fdtable[x]) && y > max_zsh_fd)
            max_zsh_fd = y;
        zclose(x);
    }
}

/* Close the given fd, and clear it from fdtable. */

/**/
mod_export int
zclose(int fd)
{
    if (fd >= 0) {
        fdtable[fd] = FDT_UNUSED;
        while (max_zsh_fd > 0 && fdtable[max_zsh_fd] == FDT_UNUSED)
            max_zsh_fd--;
        if (fd == coprocin)
            coprocin = -1;
        if (fd == coprocout)
            coprocout = -1;
        return close(fd);
    }
    return -1;
}

#ifdef HAVE__MKTEMP
extern char *_mktemp(char *);
#endif

/* Get a unique filename for use as a temporary file.  If "prefix" is
 * NULL, the name is relative to $TMPPREFIX; If it is non-NULL, the
 * unique suffix includes a prefixed '.' for improved readability.  If
 * "use_heap" is true, we allocate the returned name on the heap. */

/**/
mod_export char *
gettempname(const char *prefix, int use_heap)
{
    char *ret, *suffix = prefix ? ".XXXXXX" : "XXXXXX";

    queue_signals();
    if (!prefix && !(prefix = getsparam("TMPPREFIX")))
        prefix = DEFAULT_TMPPREFIX;
    if (use_heap)
        ret = dyncat(unmeta(prefix), suffix);
    else
        ret = bicat(unmeta(prefix), suffix);

#ifdef HAVE__MKTEMP
    /* Zsh uses mktemp() safely, so silence the warnings */
    ret = (char *) _mktemp(ret);
#else
    ret = (char *) mktemp(ret);
#endif
    unqueue_signals();

    return ret;
}

/**/
mod_export int
gettempfile(const char *prefix, int use_heap, char **tempname)
{
    char *fn;
    int fd;
#if HAVE_MKSTEMP
    char *suffix = prefix ? ".XXXXXX" : "XXXXXX";

    if (!prefix && !(prefix = getsparam("TMPPREFIX")))
        prefix = DEFAULT_TMPPREFIX;
    if (use_heap)
        fn = dyncat(unmeta(prefix), suffix);
    else
        fn = bicat(unmeta(prefix), suffix);

    fd = mkstemp(fn);
    if (fd < 0) {
        if (!use_heap)
            free(fn);
        fn = NULL;
    }
#else
    int failures = 0;

    do {
        if (!(fn = gettempname(prefix, use_heap))) {
            fd = -1;
            break;
        }
        if ((fd = open(fn, O_RDWR | O_CREAT | O_EXCL, 0600)) >= 0)
            break;
        if (!use_heap)
            free(fn);
        fn = NULL;
    } while (errno == EEXIST && ++failures < 16);
#endif
    *tempname = fn;
    return fd;
}

/* Check if a string contains a token */

/**/
mod_export int
has_token(const char *s)
{
    while(*s)
        if(itok(*s++))
            return 1;
    return 0;
}

/* Delete a character in a string */

/**/
mod_export void
chuck(char *str)
{
    while ((str[0] = str[1]))
        str++;
}

/**/
mod_export int
tulower(int c)
{
    c &= 0xff;
    return (isupper(c) ? tolower(c) : c);
}

/**/
mod_export int
tuupper(int c)
{
    c &= 0xff;
    return (islower(c) ? toupper(c) : c);
}

/* copy len chars from t into s, and null terminate */

/**/
void
ztrncpy(char *s, char *t, int len)
{
    while (len--)
        *s++ = *t++;
    *s = '\0';
}

/* copy t into *s and update s */

/**/
mod_export void
strucpy(char **s, char *t)
{
    char *u = *s;

    while ((*u++ = *t++));
    *s = u - 1;
}

/**/
mod_export void
struncpy(char **s, char *t, int n)
{
    char *u = *s;

    while (n--)
        *u++ = *t++;
    *s = u;
    *u = '\0';
}

/* Return the number of elements in an array of pointers. *
 * It doesn't count the NULL pointer at the end.          */

/**/
mod_export int
arrlen(char **s)
{
    int count;

    for (count = 0; *s; s++, count++);
    return count;
}

/* Skip over a balanced pair of parenthesis. */

/**/
mod_export int
skipparens(char inpar, char outpar, char **s)
{
    int level;

    if (**s != inpar)
        return -1;

    for (level = 1; *++*s && level;)
        if (**s == inpar)
           ++level;
        else if (**s == outpar)
           --level;

   return level;
}

/* Convert string to zlong (see zsh.h).  This function (without the z) *
 * is contained in the ANSI standard C library, but a lot of them seem *
 * to be broken.                                                       */

/**/
mod_export zlong
zstrtol(const char *s, char **t, int base)
{
    const char *inp, *trunc = NULL;
    zulong calc = 0, newcalc = 0;
    int neg;

    while (inblank(*s))
        s++;

    if ((neg = (*s == '-')))
        s++;
    else if (*s == '+')
        s++;

    if (!base) {
        if (*s != '0')
            base = 10;
        else if (*++s == 'x' || *s == 'X')
            base = 16, s++;
        else
            base = 8;
    }
    inp = s;
    if (base < 2 || base > 36) {
        zerr("invalid base (must be 2 to 36 inclusive): %d", base);
        return (zlong)0;
    } else if (base <= 10)
        for (; *s >= '0' && *s < ('0' + base); s++) {
            if (trunc)
                continue;
            newcalc = calc * base + *s - '0';
            if (newcalc < calc)
            {
              trunc = s;
              continue;
            }
            calc = newcalc;
        }
    else
        for (; idigit(*s) || (*s >= 'a' && *s < ('a' + base - 10))
             || (*s >= 'A' && *s < ('A' + base - 10)); s++) {
            if (trunc)
                continue;
            newcalc = calc*base + (idigit(*s) ? (*s - '0') : (*s & 0x1f) + 9);
            if (newcalc < calc)
            {
                trunc = s;
                continue;
            }
            calc = newcalc;
        }

    /*
     * Special case: check for a number that was just too long for
     * signed notation.
     * Extra special case: the lowest negative number would trigger
     * the first test, but is actually representable correctly.
     * This is a 1 in the top bit, all others zero, so test for
     * that explicitly.
     */
    if (!trunc && (zlong)calc < 0 &&
        (!neg || calc & ~((zulong)1 << (8*sizeof(zulong)-1))))
    {
        trunc = s - 1;
        calc /= base;
    }

    if (trunc)
        zwarn("number truncated after %d digits: %s", (int)(trunc - inp), inp);

    if (t)
        *t = (char *)s;
    return neg ? -(zlong)calc : (zlong)calc;
}

/**/
mod_export int
setblock_fd(int turnonblocking, int fd, long *modep)
{
#ifdef O_NDELAY
# ifdef O_NONBLOCK
#  define NONBLOCK (O_NDELAY|O_NONBLOCK)
# else /* !O_NONBLOCK */
#  define NONBLOCK O_NDELAY
# endif /* !O_NONBLOCK */
#else /* !O_NDELAY */
# ifdef O_NONBLOCK
#  define NONBLOCK O_NONBLOCK
# else /* !O_NONBLOCK */
#  define NONBLOCK 0
# endif /* !O_NONBLOCK */
#endif /* !O_NDELAY */

#if NONBLOCK
    struct stat st;

    if (!fstat(fd, &st) && !S_ISREG(st.st_mode)) {
        *modep = fcntl(fd, F_GETFL, 0);
        if (*modep != -1) {
            if (!turnonblocking) {
                /* We want to know if blocking was off */
                if ((*modep & NONBLOCK) ||
                    !fcntl(fd, F_SETFL, *modep | NONBLOCK))
                    return 1;
            } else if ((*modep & NONBLOCK) &&
                       !fcntl(fd, F_SETFL, *modep & ~NONBLOCK)) {
                /* Here we want to know if the state changed */
                return 1;
            }
        }
    } else
#endif /* NONBLOCK */
        *modep = -1;
    return 0;

#undef NONBLOCK
}

/**/
int
setblock_stdin(void)
{
    long mode;
    return setblock_fd(1, 0, &mode);
}

/*
 * Check for pending input on fd.  If polltty is set, we may need to
 * use termio to look for input.  As a final resort, go to non-blocking
 * input and try to read a character, which in this case will be
 * returned in *readchar.
 *
 * Note that apart from setting (and restoring) non-blocking input,
 * this function does not change the input mode.  The calling function
 * should have set cbreak mode if necessary.
 */

/**/
mod_export int
read_poll(int fd, int *readchar, int polltty, zlong microseconds)
{
    int ret = -1;
    long mode = -1;
    char c;
#ifdef HAVE_SELECT
    fd_set foofd;
    struct timeval expire_tv;
#else
#ifdef FIONREAD
    int val;
#endif
#endif
#ifdef HAS_TIO
    struct ttyinfo ti;
#endif


#if defined(HAS_TIO) && !defined(__CYGWIN__)
    /*
     * Under Solaris, at least, reading from the terminal in non-canonical
     * mode requires that we use the VMIN mechanism to poll.  Any attempt
     * to check any other way, or to set the terminal to non-blocking mode
     * and poll that way, fails; it will just for canonical mode input.
     * We should probably use this mechanism if the user has set non-canonical
     * mode, in which case testing here for isatty() and ~ICANON would be
     * better than testing whether bin_read() set it, but for now we've got
     * enough problems.
     *
     * Under Cygwin, you won't be surprised to here, this mechanism,
     * although present, doesn't work, and we *have* to use ordinary
     * non-blocking reads to find out if there is a character present
     * in non-canonical mode.
     *
     * I am assuming Solaris is nearer the UNIX norm.  This is not necessarily
     * as plausible as it sounds, but it seems the right way to guess.
     *          pws 2000/06/26
     */
    if (polltty) {
        gettyinfo(&ti);
        if ((polltty = ti.tio.c_cc[VMIN])) {
            ti.tio.c_cc[VMIN] = 0;
            /* termios timeout is 10ths of a second */
            ti.tio.c_cc[VTIME] = (int) (microseconds / (zlong)100000);
            settyinfo(&ti);
        }
    }
#else
    polltty = 0;
#endif
#ifdef HAVE_SELECT
    expire_tv.tv_sec = (int) (microseconds / (zlong)1000000);
    expire_tv.tv_usec = microseconds % (zlong)1000000;
    FD_ZERO(&foofd);
    FD_SET(fd, &foofd);
    ret = select(fd+1, (SELECT_ARG_2_T) &foofd, NULL, NULL, &expire_tv);
#else
#ifdef FIONREAD
    if (ioctl(fd, FIONREAD, (char *) &val) == 0)
        ret = (val > 0);
#endif
#endif

    if (ret < 0) {
        /*
         * Final attempt: set non-blocking read and try to read a character.
         * Praise Bill, this works under Cygwin (nothing else seems to).
         */
        if ((polltty || setblock_fd(0, fd, &mode)) && read(fd, &c, 1) > 0) {
            *readchar = c;
            ret = 1;
        }
        if (mode != -1)
            fcntl(fd, F_SETFL, mode);
    }
#ifdef HAS_TIO
    if (polltty) {
        ti.tio.c_cc[VMIN] = 1;
        ti.tio.c_cc[VTIME] = 0;
        settyinfo(&ti);
    }
#endif
    return (ret > 0);
}

/**/
int
checkrmall(char *s)
{
    if (!shout)
        return 1;
    fprintf(shout, "zsh: sure you want to delete all the files in ");
    if (*s != '/') {
        nicezputs(pwd[1] ? unmeta(pwd) : "", shout);
        fputc('/', shout);
    }
    nicezputs(s, shout);
    if(isset(RMSTARWAIT)) {
        fputs("? (waiting ten seconds)", shout);
        fflush(shout);
        zbeep();
        sleep(10);
        fputc('\n', shout);
    }
    fputs(" [yn]? ", shout);
    fflush(shout);
    zbeep();
    return (getquery("ny", 1) == 'y');
}

static int
read1char(int echo)
{
    char c;

    while (read(SHTTY, &c, 1) != 1) {
        if (errno != EINTR || errflag || retflag || breaks || contflag)
            return -1;
    }
    if (echo)
        write(SHTTY, &c, 1);
    return STOUC(c);
}

/**/
mod_export int
noquery(int purge)
{
    int val = 0;

#ifdef FIONREAD
    char c;

    ioctl(SHTTY, FIONREAD, (char *)&val);
    if (purge) {
        for (; val; val--)
            read(SHTTY, &c, 1);
    }
#endif

    return val;
}

/**/
int
getquery(char *valid_chars, int purge)
{
    int c, d, nl = 0;
    int isem = !strcmp(term, "emacs");
    struct ttyinfo ti;

    attachtty(mypgrp);

    gettyinfo(&ti);
#ifdef HAS_TIO
    ti.tio.c_lflag &= ~ECHO;
    if (!isem) {
        ti.tio.c_lflag &= ~ICANON;
        ti.tio.c_cc[VMIN] = 1;
        ti.tio.c_cc[VTIME] = 0;
    }
#else
    ti.sgttyb.sg_flags &= ~ECHO;
    if (!isem)
        ti.sgttyb.sg_flags |= CBREAK;
#endif
    settyinfo(&ti);

    if (noquery(purge)) {
        if (!isem)
            settyinfo(&shttyinfo);
        write(SHTTY, "n\n", 2);
        return 'n';
    }

    while ((c = read1char(0)) >= 0) {
        if (c == 'Y')
            c = 'y';
        else if (c == 'N')
            c = 'n';
        if (!valid_chars)
            break;
        if (c == '\n') {
            c = *valid_chars;
            nl = 1;
            break;
        }
        if (strchr(valid_chars, c)) {
            nl = 1;
            break;
        }
        zbeep();
    }
    if (c >= 0)
        write(SHTTY, &c, 1);
    if (nl)
        write(SHTTY, "\n", 1);

    if (isem) {
        if (c != '\n')
            while ((d = read1char(1)) >= 0 && d != '\n');
    } else {
        if (c != '\n' && !valid_chars) {
#ifdef MULTIBYTE_SUPPORT
            if (isset(MULTIBYTE) && c >= 0) {
                /*
                 * No waiting for a valid character, and no draining;
                 * we should ensure we haven't stopped in the middle
                 * of a multibyte character.
                 */
                mbstate_t mbs;
                char cc = (char)c;
                memset(&mbs, 0, sizeof(mbs));
                for (;;) {
                    size_t ret = mbrlen(&cc, 1, &mbs);

                    if (ret != MB_INCOMPLETE)
                        break;
                    c = read1char(1);
                    if (c < 0)
                        break;
                    cc = (char)c;
                }
            }
#endif
            write(SHTTY, "\n", 1);
        }
    }
    settyinfo(&shttyinfo);
    return c;
}

static int d;
static char *guess, *best;

/**/
static void
spscan(HashNode hn, UNUSED(int scanflags))
{
    int nd;

    nd = spdist(hn->nam, guess, (int) strlen(guess) / 4 + 1);
    if (nd <= d) {
        best = hn->nam;
        d = nd;
    }
}

/* spellcheck a word */
/* fix s ; if hist is nonzero, fix the history list too */

/**/
mod_export void
spckword(char **s, int hist, int cmd, int ask)
{
    char *t;
    int x;
    char ic = '\0';
    int ne;
    int preflen = 0;
    int autocd = cmd && isset(AUTOCD) && strcmp(*s, ".") && strcmp(*s, "..");

    if ((histdone & HISTFLAG_NOEXEC) || **s == '-' || **s == '%')
        return;
    if (!strcmp(*s, "in"))
        return;
    if (!(*s)[0] || !(*s)[1])
        return;
    if (shfunctab->getnode(shfunctab, *s) ||
        builtintab->getnode(builtintab, *s) ||
        cmdnamtab->getnode(cmdnamtab, *s) ||
        aliastab->getnode(aliastab, *s)  ||
        reswdtab->getnode(reswdtab, *s))
        return;
    else if (isset(HASHLISTALL)) {
        cmdnamtab->filltable(cmdnamtab);
        if (cmdnamtab->getnode(cmdnamtab, *s))
            return;
    }
    t = *s;
    if (*t == Tilde || *t == Equals || *t == String)
        t++;
    for (; *t; t++)
        if (itok(*t))
            return;
    best = NULL;
    for (t = *s; *t; t++)
        if (*t == '/')
            break;
    if (**s == Tilde && !*t)
        return;
    if (**s == String && !*t) {
        guess = *s + 1;
        if (itype_end(guess, IIDENT, 1) == guess)
            return;
        ic = String;
        d = 100;
        scanhashtable(paramtab, 1, 0, 0, spscan, 0);
    } else if (**s == Equals) {
        if (*t)
            return;
        if (hashcmd(guess = *s + 1, pathchecked))
            return;
        d = 100;
        ic = Equals;
        scanhashtable(aliastab, 1, 0, 0, spscan, 0);
        scanhashtable(cmdnamtab, 1, 0, 0, spscan, 0);
    } else {
        guess = *s;
        if (*guess == Tilde || *guess == String) {
            ic = *guess;
            if (!*++t)
                return;
            guess = dupstring(guess);
            ne = noerrs;
            noerrs = 2;
            singsub(&guess);
            noerrs = ne;
            if (!guess)
                return;
            preflen = strlen(guess) - strlen(t);
        }
        if (access(unmeta(guess), F_OK) == 0)
            return;
        best = spname(guess);
        if (!*t && cmd) {
            if (hashcmd(guess, pathchecked))
                return;
            d = 100;
            scanhashtable(reswdtab, 1, 0, 0, spscan, 0);
            scanhashtable(aliastab, 1, 0, 0, spscan, 0);
            scanhashtable(shfunctab, 1, 0, 0, spscan, 0);
            scanhashtable(builtintab, 1, 0, 0, spscan, 0);
            scanhashtable(cmdnamtab, 1, 0, 0, spscan, 0);
            if (autocd) {
                char **pp;
                for (pp = cdpath; *pp; pp++) {
                    char bestcd[PATH_MAX + 1];
                    int thisdist;
                    /* Less than d here, instead of less than or equal  *
                     * as used in spscan(), so that an autocd is chosen *
                     * only when it is better than anything so far, and *
                     * so we prefer directories earlier in the cdpath.  */
                    if ((thisdist = mindist(*pp, *s, bestcd)) < d) {
                        best = dupstring(bestcd);
                        d = thisdist;
                    }
                }
            }
        }
    }
    if (errflag)
        return;
    if (best && (int)strlen(best) > 1 && strcmp(best, guess)) {
        if (ic) {
            char *u;
            if (preflen) {
                /* do not correct the result of an expansion */
                if (strncmp(guess, best, preflen))
                    return;
                /* replace the temporarily expanded prefix with the original */
                u = (char *) hcalloc(t - *s + strlen(best + preflen) + 1);
                strncpy(u, *s, t - *s);
                strcpy(u + (t - *s), best + preflen);
            } else {
                u = (char *) hcalloc(strlen(best) + 2);
                strcpy(u + 1, best);
            }
            best = u;
            guess = *s;
            *guess = *best = ztokens[ic - Pound];
        }
        if (ask) {
            if (noquery(0)) {
                x = 'n';
            } else if (shout) {
                char *pptbuf;
                pptbuf = promptexpand(sprompt, 0, best, guess, NULL);
                zputs(pptbuf, shout);
                free(pptbuf);
                fflush(shout);
                zbeep();
                x = getquery("nyae \t", 0);
            } else
                x = 'n';
        } else
            x = 'y';
        if (x == 'y' || x == ' ' || x == '\t') {
            *s = dupstring(best);
            if (hist)
                hwrep(best);
        } else if (x == 'a') {
            histdone |= HISTFLAG_NOEXEC;
        } else if (x == 'e') {
            histdone |= HISTFLAG_NOEXEC | HISTFLAG_RECALL;
        }
        if (ic)
            **s = ic;
    }
}

/*
 * Helper for ztrftime.  Called with a pointer to the length left
 * in the buffer, and a new string length to decrement from that.
 * Returns 0 if the new length fits, 1 otherwise.  We assume a terminating
 * NUL and return 1 if that doesn't fit.
 */

static int
ztrftimebuf(int *bufsizeptr, int decr)
{
    if (*bufsizeptr <= decr)
        return 1;
    *bufsizeptr -= decr;
    return 0;
}

/*
 * Like the system function, this returns the number of characters
 * copied, not including the terminating NUL.  This may be zero
 * if the string didn't fit.
 *
 * As an extension, try to detect an error in strftime --- typically
 * not enough memory --- and return -1.  Not guaranteed to be portable,
 * since the strftime() interface doesn't make any guarantees about
 * the state of the buffer if it returns zero.
 */

/**/
mod_export int
ztrftime(char *buf, int bufsize, char *fmt, struct tm *tm)
{
    int hr12, decr;
#ifndef HAVE_STRFTIME
    static char *astr[] =
    {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};
    static char *estr[] =
    {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul",
     "Aug", "Sep", "Oct", "Nov", "Dec"};
#endif
    char *origbuf = buf;
    char tmp[4];


    while (*fmt)
        if (*fmt == '%') {
            int strip;

            fmt++;
            if (*fmt == '-') {
                strip = 1;
                fmt++;
            } else
                strip = 0;
            /*
             * Assume this format will take up at least two
             * characters.  Not always true, but if that matters
             * we are so close to the edge it's not a big deal.
             * Fix up some longer cases specially when we get to them.
             */
            if (ztrftimebuf(&bufsize, 2))
                return -1;
            switch (*fmt++) {
            case 'd':
                if (tm->tm_mday > 9 || !strip)
                    *buf++ = '0' + tm->tm_mday / 10;
                *buf++ = '0' + tm->tm_mday % 10;
                break;
            case 'e':
                strip = 1;
                /* FALLTHROUGH */
            case 'f':
                if (tm->tm_mday > 9)
                    *buf++ = '0' + tm->tm_mday / 10;
                else if (!strip)
                    *buf++ = ' ';
                *buf++ = '0' + tm->tm_mday % 10;
                break;
            case 'K':
                strip = 1;
                /* FALLTHROUGH */
            case 'H':
            case 'k':
                if (tm->tm_hour > 9)
                    *buf++ = '0' + tm->tm_hour / 10;
                else if (!strip) {
                    if (fmt[-1] == 'H')
                        *buf++ = '0';
                    else
                        *buf++ = ' ';
                }
                *buf++ = '0' + tm->tm_hour % 10;
                break;
            case 'L':
                strip = 1;
                /* FALLTHROUGH */
            case 'l':
                hr12 = tm->tm_hour % 12;
                if (hr12 == 0)
                    hr12 = 12;
                if (hr12 > 9)
                    *buf++ = '1';
                else if (!strip)
                    *buf++ = ' ';

                *buf++ = '0' + (hr12 % 10);
                break;
            case 'm':
                if (tm->tm_mon > 8 || !strip)
                    *buf++ = '0' + (tm->tm_mon + 1) / 10;
                *buf++ = '0' + (tm->tm_mon + 1) % 10;
                break;
            case 'M':
                if (tm->tm_min > 9 || !strip)
                    *buf++ = '0' + tm->tm_min / 10;
                *buf++ = '0' + tm->tm_min % 10;
                break;
            case 'S':
                if (tm->tm_sec > 9 || !strip)
                    *buf++ = '0' + tm->tm_sec / 10;
                *buf++ = '0' + tm->tm_sec % 10;
                break;
            case 'y':
                if (tm->tm_year > 9 || !strip)
                    *buf++ = '0' + (tm->tm_year / 10) % 10;
                *buf++ = '0' + tm->tm_year % 10;
                break;
            case '\0':
                /* Guard against premature end of string */
                *buf++ = '%';
                fmt--;
                break;
#ifndef HAVE_STRFTIME
            case 'Y':
            {
                /*
                 * Not worth handling this natively if
                 * strftime has it.
                 */
                int year, digits, testyear;
                year = tm->tm_year + 1900;
                digits = 1;
                testyear = year;
                while (testyear > 9) {
                    digits++;
                    testyear /= 10;
                }
                if (ztrftimebuf(&bufsize, digits))
                    return -1;
                sprintf(buf, "%d", year);
                buf += digits;
                break;
            }
            case 'a':
                if (ztrftimebuf(&bufsize, strlen(astr[tm->tm_wday]) - 2))
                    return -1;
                strucpy(&buf, astr[tm->tm_wday]);
                break;
            case 'b':
                if (ztrftimebuf(&bufsize, strlen(estr[tm->tm_mon]) - 2))
                    return -1;
                strucpy(&buf, estr[tm->tm_mon]);
                break;
            case 'p':
                *buf++ = (tm->tm_hour > 11) ? 'p' : 'a';
                *buf++ = 'm';
                break;
            default:
                *buf++ = '%';
                if (fmt[-1] != '%')
                    *buf++ = fmt[-1];
#else
            default:
                /*
                 * Remember we've already allowed for two characters
                 * in the accounting in bufsize (but nowhere else).
                 */
                *buf = '\1';
                sprintf(tmp, strip ? "%%-%c" : "%%%c", fmt[-1]);
                if (!strftime(buf, bufsize + 2, tmp, tm))
                {
                    if (*buf) {
                        buf[0] = '\0';
                        return -1;
                    }
                    return 0;
                }
                decr = strlen(buf);
                buf += decr;
                bufsize -= decr - 2;
#endif
                break;
            }
        } else {
            if (ztrftimebuf(&bufsize, 1))
                return -1;
            *buf++ = *fmt++;
        }
    *buf = '\0';
    return buf - origbuf;
}

/**/
mod_export char *
zjoin(char **arr, int delim, int heap)
{
    int len = 0;
    char **s, *ret, *ptr;

    for (s = arr; *s; s++)
        len += strlen(*s) + 1 + (imeta(delim) ? 1 : 0);
    if (!len)
        return heap? "" : ztrdup("");
    ptr = ret = (heap ? (char *) hcalloc(len) : (char *) zshcalloc(len));
    for (s = arr; *s; s++) {
        strucpy(&ptr, *s);
            if (imeta(delim)) {
                *ptr++ = Meta;
                *ptr++ = delim ^ 32;
            }
            else
                *ptr++ = delim;
    }
    ptr[-1 - (imeta(delim) ? 1 : 0)] = '\0';
    return ret;
}

/* Split a string containing a colon separated list *
 * of items into an array of strings.               */

/**/
char **
colonsplit(char *s, int uniq)
{
    int ct;
    char *t, **ret, **ptr, **p;

    for (t = s, ct = 0; *t; t++) /* count number of colons */
        if (*t == ':')
            ct++;
    ptr = ret = (char **) zalloc(sizeof(char **) * (ct + 2));

    t = s;
    do {
        s = t;
        /* move t to point at next colon */
        for (; *t && *t != ':'; t++);
        if (uniq)
            for (p = ret; p < ptr; p++)
                if ((int)strlen(*p) == t - s && ! strncmp(*p, s, t - s))
                    goto cont;
        *ptr = (char *) zalloc((t - s) + 1);
        ztrncpy(*ptr++, s, t - s);
      cont: ;
    }
    while (*t++);
    *ptr = NULL;
    return ret;
}

/**/
static int
skipwsep(char **s)
{
    char *t = *s;
    int i = 0;

    /*
     * Don't need to handle mutlibyte characters, they can't
     * be IWSEP.  Do need to check for metafication.
     */
    while (*t && iwsep(*t == Meta ? t[1] ^ 32 : *t)) {
        if (*t == Meta)
            t++;
        t++;
        i++;
    }
    *s = t;
    return i;
}

/*
 * haven't worked out what allownull does; it's passed down from
 *   sepsplit but all the cases it's used are either 0 or 1 without
 *   a comment.  it seems to be something to do with the `nulstring'
 *   which i think is some kind of a metafication thing, so probably
 *   allownull's value is associated with whether we are using
 *   metafied strings.
 * see findsep() below for handling of `quote' argument
 */

/**/
mod_export char **
spacesplit(char *s, int allownull, int heap, int quote)
{
    char *t, **ret, **ptr;
    int l = sizeof(*ret) * (wordcount(s, NULL, -!allownull) + 1);
    char *(*dup)(const char *) = (heap ? dupstring : ztrdup);

    ptr = ret = (heap ? (char **) hcalloc(l) : (char **) zshcalloc(l));

    if (quote) {
        /*
         * we will be stripping quoted separators by hacking string,
         * so make sure it's hackable.
         */
        s = dupstring(s);
    }

    t = s;
    skipwsep(&s);
    MB_METACHARINIT();
    if (*s && itype_end(s, ISEP, 1) != s)
        *ptr++ = dup(allownull ? "" : nulstring);
    else if (!allownull && t != s)
        *ptr++ = dup("");
    while (*s) {
        char *iend = itype_end(s, ISEP, 1);
        if (iend != s) {
            s = iend;
            skipwsep(&s);
        }
        else if (quote && *s == '\\') {
            s++;
            skipwsep(&s);
        }
        t = s;
        (void)findsep(&s, NULL, quote);
        if (s > t || allownull) {
            *ptr = (heap ? (char *) hcalloc((s - t) + 1) :
                    (char *) zshcalloc((s - t) + 1));
            ztrncpy(*ptr++, t, s - t);
        } else
            *ptr++ = dup(nulstring);
        t = s;
        skipwsep(&s);
    }
    if (!allownull && t != s)
        *ptr++ = dup("");
    *ptr = NULL;
    return ret;
}

/*
 * Find a separator.  Return 0 if already at separator, 1 if separator
 * found later, else -1.  (Historical note: used to return length into
 * string but this is all that is necessary and is less ambiguous with
 * multibyte characters around.)
 *
 * *s is the string we are looking along, which will be updated
 * to the point we have got to.
 *
 * sep is a possibly multicharacter separator to look for.  If NULL,
 * use normal separator characters.  If *sep is NULL, split on individual
 * characters.
 *
 * quote is a flag that '\<sep>' should not be treated as a separator.
 * in this case we need to be able to strip the backslash directly
 * in the string, so the calling function must have sent us something
 * modifiable.  currently this only works for sep == NULL.  also in
 * in this case only, we need to turn \\ into \.
 */

/**/
static int
findsep(char **s, char *sep, int quote)
{
    /*
     */
    int i, ilen;
    char *t, *tt;
    convchar_t c;

    MB_METACHARINIT();
    if (!sep) {
        for (t = *s; *t; t += ilen) {
            if (quote && *t == '\\') {
                if (t[1] == '\\') {
                    chuck(t);
                    ilen = 1;
                    continue;
                } else {
                    ilen = MB_METACHARLENCONV(t+1, &c);
                    if (WC_ZISTYPE(c, ISEP)) {
                        chuck(t);
                        /* then advance over new character, length ilen */
                    } else {
                        /* treat *t (backslash) as normal byte */
                        if (isep(*t))
                            break;
                        ilen = 1;
                    }
                }
            } else {
                ilen = MB_METACHARLENCONV(t, &c);
                if (WC_ZISTYPE(c, ISEP))
                    break;
            }
        }
        i = (t > *s);
        *s = t;
        return i;
    }
    if (!sep[0]) {
        /*
         * NULL separator just means advance past first character,
         * if any.
         */
        if (**s) {
            *s += MB_METACHARLEN(*s);
            return 1;
        }
        return -1;
    }
    for (i = 0; **s; i++) {
        /*
         * The following works for multibyte characters by virtue of
         * the fact that sep may be a string (and we don't care how
         * it divides up, we need to match all of it).
         */
        for (t = sep, tt = *s; *t && *tt && *t == *tt; t++, tt++);
        if (!*t)
            return (i > 0);
        *s += MB_METACHARLEN(*s);
    }
    return -1;
}

/**/
char *
findword(char **s, char *sep)
{
    char *r, *t;
    int sl;

    if (!**s)
        return NULL;

    if (sep) {
        sl = strlen(sep);
        r = *s;
        while (! findsep(s, sep, 0)) {
            r = *s += sl;
        }
        return r;
    }
    MB_METACHARINIT();
    for (t = *s; *t; t += sl) {
        convchar_t c;
        sl = MB_METACHARLENCONV(t, &c);
        if (!WC_ZISTYPE(c, ISEP))
            break;
    }
    *s = t;
    (void)findsep(s, sep, 0);
    return t;
}

/**/
int
wordcount(char *s, char *sep, int mul)
{
    int r, sl, c;

    if (sep) {
        r = 1;
        sl = strlen(sep);
        for (; (c = findsep(&s, sep, 0)) >= 0; s += sl)
            if ((c && *(s + sl)) || mul)
                r++;
    } else {
        char *t = s;

        r = 0;
        if (mul <= 0)
            skipwsep(&s);
        if ((*s && itype_end(s, ISEP, 1) != s) ||
            (mul < 0 && t != s))
            r++;
        for (; *s; r++) {
            char *ie = itype_end(s, ISEP, 1);
            if (ie != s) {
                s = ie;
                if (mul <= 0)
                    skipwsep(&s);
            }
            (void)findsep(&s, NULL, 0);
            t = s;
            if (mul <= 0)
                skipwsep(&s);
        }
        if (mul < 0 && t != s)
            r++;
    }
    return r;
}

/**/
mod_export char *
sepjoin(char **s, char *sep, int heap)
{
    char *r, *p, **t;
    int l, sl;
    char sepbuf[2];

    if (!*s)
        return heap ? "" : ztrdup("");
    if (!sep) {
        /* optimise common case that ifs[0] is space */
        if (ifs && *ifs != ' ') {
            MB_METACHARINIT();
            sep = dupstrpfx(ifs, MB_METACHARLEN(ifs));
        } else {
            p = sep = sepbuf;
            *p++ = ' ';
            *p = '\0';
        }
    }
    sl = strlen(sep);
    for (t = s, l = 1 - sl; *t; l += strlen(*t) + sl, t++);
    r = p = (heap ? (char *) hcalloc(l) : (char *) zshcalloc(l));
    t = s;
    while (*t) {
        strucpy(&p, *t);
        if (*++t)
            strucpy(&p, sep);
    }
    *p = '\0';
    return r;
}

/**/
char **
sepsplit(char *s, char *sep, int allownull, int heap)
{
    int n, sl;
    char *t, *tt, **r, **p;

    if (!sep)
        return spacesplit(s, allownull, heap, 0);

    sl = strlen(sep);
    n = wordcount(s, sep, 1);
    r = p = (heap ? (char **) hcalloc((n + 1) * sizeof(char *)) :
             (char **) zshcalloc((n + 1) * sizeof(char *)));

    for (t = s; n--;) {
        tt = t;
        (void)findsep(&t, sep, 0);
        *p = (heap ? (char *) hcalloc(t - tt + 1) :
              (char *) zshcalloc(t - tt + 1));
        strncpy(*p, tt, t - tt);
        (*p)[t - tt] = '\0';
        p++;
        t += sl;
    }
    *p = NULL;

    return r;
}

/* Get the definition of a shell function */

/**/
mod_export Shfunc
getshfunc(char *nam)
{
    return (Shfunc) shfunctab->getnode(shfunctab, nam);
}

/*
 * Call the function func to substitute string orig by setting
 * the parameter reply.
 * Return the array from reply, or NULL if the function returned
 * non-zero status.
 * The returned value comes directly from the parameter and
 * so should be used before there is any chance of that
 * being changed or unset.
 * If arg1 is not NULL, it is used as an initial argument to
 * the function, with the original string as the second argument.
 */

/**/
char **
subst_string_by_func(Shfunc func, char *arg1, char *orig)
{
    int osc = sfcontext;
    LinkList l = newlinklist();
    char **ret;

    addlinknode(l, func->node.nam);
    if (arg1)
        addlinknode(l, arg1);
    addlinknode(l, orig);
    sfcontext = SFC_SUBST;

    if (doshfunc(func, l, 1))
        ret = NULL;
    else
        ret = getaparam("reply");

    sfcontext = osc;
    return ret;
}

/**/
mod_export char **
mkarray(char *s)
{
    char **t = (char **) zalloc((s) ? (2 * sizeof s) : (sizeof s));

    if ((*t = s))
        t[1] = NULL;
    return t;
}

/**/
mod_export void
zbeep(void)
{
    char *vb;
    queue_signals();
    if ((vb = getsparam("ZBEEP"))) {
        int len;
        vb = getkeystring(vb, &len, GETKEYS_BINDKEY, NULL);
        write(SHTTY, vb, len);
    } else if (isset(BEEP))
        write(SHTTY, "\07", 1);
    unqueue_signals();
}

/**/
mod_export void
freearray(char **s)
{
    char **t = s;

    DPUTS(!s, "freearray() with zero argument");

    while (*s)
        zsfree(*s++);
    free(t);
}

/**/
int
equalsplit(char *s, char **t)
{
    for (; *s && *s != '='; s++);
    if (*s == '=') {
        *s++ = '\0';
        *t = s;
        return 1;
    }
    return 0;
}

static int specialcomma;

/* the ztypes table */

/**/
mod_export short int typtab[256];

/* initialize the ztypes table */

/**/
void
inittyptab(void)
{
    int t0;
    char *s;

    for (t0 = 0; t0 != 256; t0++)
        typtab[t0] = 0;
    for (t0 = 0; t0 != 32; t0++)
        typtab[t0] = typtab[t0 + 128] = ICNTRL;
    typtab[127] = ICNTRL;
    for (t0 = '0'; t0 <= '9'; t0++)
        typtab[t0] = IDIGIT | IALNUM | IWORD | IIDENT | IUSER;
    for (t0 = 'a'; t0 <= 'z'; t0++)
        typtab[t0] = typtab[t0 - 'a' + 'A'] = IALPHA | IALNUM | IIDENT | IUSER | IWORD;
#ifndef MULTIBYTE_SUPPORT
    /*
     * This really doesn't seem to me the right thing to do when
     * we have multibyte character support...  it was a hack to assume
     * eight bit characters `worked' for some values of work before
     * we could test for them properly.  I'm not 100% convinced
     * having IIDENT here is a good idea at all, but this code
     * should disappear into history...
     */
    for (t0 = 0240; t0 != 0400; t0++)
        typtab[t0] = IALPHA | IALNUM | IIDENT | IUSER | IWORD;
#endif
    /* typtab['.'] |= IIDENT; */ /* Allow '.' in variable names - broken */
    typtab['_'] = IIDENT | IUSER;
    typtab['-'] = typtab['.'] = IUSER;
    typtab[' '] |= IBLANK | INBLANK;
    typtab['\t'] |= IBLANK | INBLANK;
    typtab['\n'] |= INBLANK;
    typtab['\0'] |= IMETA;
    typtab[STOUC(Meta)  ] |= IMETA;
    typtab[STOUC(Marker)] |= IMETA;
    for (t0 = (int)STOUC(Pound); t0 <= (int)STOUC(Comma); t0++)
        typtab[t0] |= ITOK | IMETA;
    for (t0 = (int)STOUC(Snull); t0 <= (int)STOUC(Nularg); t0++)
        typtab[t0] |= ITOK | IMETA | INULL;
    for (s = ifs ? ifs : DEFAULT_IFS; *s; s++) {
        int c = STOUC(*s == Meta ? *++s ^ 32 : *s);
#ifdef MULTIBYTE_SUPPORT
        if (!isascii(c)) {
            /* see comment for wordchars below */
            continue;
        }
#endif
        if (inblank(c)) {
            if (s[1] == c)
                s++;
            else
                typtab[c] |= IWSEP;
        }
        typtab[c] |= ISEP;
    }
    for (s = wordchars ? wordchars : DEFAULT_WORDCHARS; *s; s++) {
        int c = STOUC(*s == Meta ? *++s ^ 32 : *s);
#ifdef MULTIBYTE_SUPPORT
        if (!isascii(c)) {
            /*
             * If we have support for multibyte characters, we don't
             * handle non-ASCII characters here; instead, we turn
             * wordchars into a wide character array.
             * (We may actually have a single-byte 8-bit character set,
             * but it works the same way.)
             */
            continue;
        }
#endif
        typtab[c] |= IWORD;
    }
#ifdef MULTIBYTE_SUPPORT
    set_widearray(wordchars, &wordchars_wide);
    set_widearray(ifs, &ifs_wide);
#endif
    for (s = SPECCHARS; *s; s++)
        typtab[STOUC(*s)] |= ISPECIAL;
    if (specialcomma)
        typtab[STOUC(',')] |= ISPECIAL;
    if (isset(BANGHIST) && bangchar && interact && isset(SHINSTDIN))
        typtab[bangchar] |= ISPECIAL;
}

/**/
mod_export void
makecommaspecial(int yesno)
{
    if ((specialcomma = yesno) != 0)
        typtab[STOUC(',')] |= ISPECIAL;
    else
        typtab[STOUC(',')] &= ~ISPECIAL;
}


/**/
#ifdef MULTIBYTE_SUPPORT
/* A wide-character version of the iblank() macro. */
/**/
mod_export int
wcsiblank(wint_t wc)
{
    if (iswspace(wc) && wc != L'\n')
        return 1;
    return 0;
}

/*
 * zistype macro extended to support wide characters.
 * Works for IIDENT, IWORD, IALNUM, ISEP.
 * We don't need this for IWSEP because that only applies to
 * a fixed set of ASCII characters.
 * Note here that use of multibyte mode is not tested:
 * that's because for ZLE this is unconditional,
 * not dependent on the option.  The caller must decide.
 */

/**/
mod_export int
wcsitype(wchar_t c, int itype)
{
    int len;
    mbstate_t mbs;
    VARARR(char, outstr, MB_CUR_MAX);

    if (!isset(MULTIBYTE))
        return zistype(c, itype);

    /*
     * Strategy:  the shell requires that the multibyte representation
     * be an extension of ASCII.  So see if converting the character
     * produces an ASCII character.  If it does, use zistype on that.
     * If it doesn't, use iswalnum on the original character.
     * If that fails, resort to the appropriate wide character array.
     */
    memset(&mbs, 0, sizeof(mbs));
    len = wcrtomb(outstr, c, &mbs);

    if (len == 0) {
        /* NULL is special */
        return zistype(0, itype);
    } else if (len == 1 && isascii(outstr[0])) {
        return zistype(outstr[0], itype);
    } else {
        switch (itype) {
        case IIDENT:
            if (!isset(POSIXIDENTIFIERS))
                return 0;
            return iswalnum(c);

        case IWORD:
            if (iswalnum(c))
                return 1;
            /*
             * If we are handling combining characters, any punctuation
             * characters with zero width needs to be considered part of
             * a word.  If we are not handling combining characters then
             * logically they are still part of the word, even if they
             * don't get displayed properly, so always do this.
             */
            if (IS_COMBINING(c))
                return 1;
            return !!wmemchr(wordchars_wide.chars, c, wordchars_wide.len);

        case ISEP:
            return !!wmemchr(ifs_wide.chars, c, ifs_wide.len);

        default:
            return iswalnum(c);
        }
    }
}

/**/
#endif


/*
 * Find the end of a set of characters in the set specified by itype;
 * one of IALNUM, IIDENT, IWORD or IUSER.  For non-ASCII characters, we assume
 * alphanumerics are part of the set, with the exception that
 * identifiers are not treated that way if POSIXIDENTIFIERS is set.
 *
 * See notes above for identifiers.
 * Returns the same pointer as passed if not on an identifier character.
 * If "once" is set, just test the first character, i.e. (outptr !=
 * inptr) tests whether the first character is valid in an identifier.
 *
 * Currently this is only called with itype IIDENT, IUSER or ISEP.
 */

/**/
mod_export char *
itype_end(const char *ptr, int itype, int once)
{
#ifdef MULTIBYTE_SUPPORT
    if (isset(MULTIBYTE) &&
        (itype != IIDENT || !isset(POSIXIDENTIFIERS))) {
        mb_metacharinit();
        while (*ptr) {
            wint_t wc;
            int len = mb_metacharlenconv(ptr, &wc);

            if (!len)
                break;

            if (wc == WEOF) {
                /* invalid, treat as single character */
                int chr = STOUC(*ptr == Meta ? ptr[1] ^ 32 : *ptr);
                /* in this case non-ASCII characters can't match */
                if (chr > 127 || !zistype(chr,itype))
                    break;
            } else if (len == 1 && isascii(*ptr)) {
                /* ASCII: can't be metafied, use standard test */
                if (!zistype(*ptr,itype))
                    break;
            } else {
                /*
                 * Valid non-ASCII character.
                 */
                switch (itype) {
                case IWORD:
                    if (!iswalnum(wc) &&
                        !wmemchr(wordchars_wide.chars, wc,
                                 wordchars_wide.len))
                        return (char *)ptr;
                    break;

                case ISEP:
                    if (!wmemchr(ifs_wide.chars, wc, ifs_wide.len))
                        return (char *)ptr;
                    break;

                default:
                    if (!iswalnum(wc))
                        return (char *)ptr;
                }
            }
            ptr += len;

            if (once)
                break;
        }
    } else
#endif
        for (;;) {
            int chr = STOUC(*ptr == Meta ? ptr[1] ^ 32 : *ptr);
            if (!zistype(chr,itype))
                break;
            ptr += (*ptr == Meta) ? 2 : 1;

            if (once)
                break;
        }

    /*
     * Nasty.  The first argument is const char * because we
     * don't modify it here.  However, we really want to pass
     * back the same type as was passed down, to allow idioms like
     *   p = itype_end(p, IIDENT, 0);
     * So returning a const char * isn't really the right thing to do.
     * Without having two different functions the following seems
     * to be the best we can do.
     */
    return (char *)ptr;
}

/**/
mod_export char **
arrdup(char **s)
{
    char **x, **y;

    y = x = (char **) zhalloc(sizeof(char *) * (arrlen(s) + 1));

    while ((*x++ = dupstring(*s++)));

    return y;
}

/**/
mod_export char **
zarrdup(char **s)
{
    char **x, **y;

    y = x = (char **) zalloc(sizeof(char *) * (arrlen(s) + 1));

    while ((*x++ = ztrdup(*s++)));

    return y;
}

/**/
#ifdef MULTIBYTE_SUPPORT
/**/
mod_export wchar_t **
wcs_zarrdup(wchar_t **s)
{
    wchar_t **x, **y;

    y = x = (wchar_t **) zalloc(sizeof(wchar_t *) * (arrlen((char **)s) + 1));

    while ((*x++ = wcs_ztrdup(*s++)));

    return y;
}
/**/
#endif /* MULTIBYTE_SUPPORT */

/**/
static char *
spname(char *oldname)
{
    char *p, spnameguess[PATH_MAX + 1], spnamebest[PATH_MAX + 1];
    static char newname[PATH_MAX + 1];
    char *new = newname, *old = oldname;
    int bestdist = 0, thisdist, thresh, maxthresh = 0;

    /* This loop corrects each directory component of the path, stopping *
     * when any correction distance would exceed the distance threshold. *
     * NULL is returned only if the first component cannot be corrected; *
     * otherwise a copy of oldname with a corrected prefix is returned.  *
     * Rationale for this, if there ever was any, has been forgotten.    */
    for (;;) {
        while (*old == '/')
            *new++ = *old++;
        *new = '\0';
        if (*old == '\0')
            return newname;
        p = spnameguess;
        for (; *old != '/' && *old != '\0'; old++)
            if (p < spnameguess + PATH_MAX)
                *p++ = *old;
        *p = '\0';
        /* Every component is allowed a single distance 2 correction or two *
         * distance 1 corrections.  Longer ones get additional corrections. */
        thresh = (int)(p - spnameguess) / 4 + 1;
        if (thresh < 3)
            thresh = 3;
        if ((thisdist = mindist(newname, spnameguess, spnamebest)) >= thresh) {
            /* The next test is always true, except for the first path    *
             * component.  We could initialize bestdist to some large     *
             * constant instead, and then compare to that constant here,  *
             * because an invariant is that we've never exceeded the      *
             * threshold for any component so far; but I think that looks *
             * odd to the human reader, and we may make use of the total  *
             * distance for all corrections at some point in the future.  */
            if (bestdist < maxthresh) {
                strcpy(new, spnameguess);
                strcat(new, old);
                return newname;
            } else
                return NULL;
        } else {
            maxthresh = bestdist + thresh;
            bestdist += thisdist;
        }
        for (p = spnamebest; (*new = *p++);)
            new++;
    }
}

/**/
static int
mindist(char *dir, char *mindistguess, char *mindistbest)
{
    int mindistd, nd;
    DIR *dd;
    char *fn;
    char buf[PATH_MAX];

    if (dir[0] == '\0')
        dir = ".";
    mindistd = 100;
    sprintf(buf, "%s/%s", dir, mindistguess);
    if (access(unmeta(buf), F_OK) == 0) {
        strcpy(mindistbest, mindistguess);
        return 0;
    }
    if (!(dd = opendir(unmeta(dir))))
        return mindistd;
    while ((fn = zreaddir(dd, 0))) {
        nd = spdist(fn, mindistguess,
                    (int)strlen(mindistguess) / 4 + 1);
        if (nd <= mindistd) {
            strcpy(mindistbest, fn);
            mindistd = nd;
            if (mindistd == 0)
                break;
        }
    }
    closedir(dd);
    return mindistd;
}

/**/
static int
spdist(char *s, char *t, int thresh)
{
    /* TODO: Correction for non-ASCII and multibyte-input keyboards. */
    char *p, *q;
    const char qwertykeymap[] =
    "\n\n\n\n\n\n\n\n\n\n\n\n\n\n\
\t1234567890-=\t\
\tqwertyuiop[]\t\
\tasdfghjkl;'\n\t\
\tzxcvbnm,./\t\t\t\
\n\n\n\n\n\n\n\n\n\n\n\n\n\n\
\t!@#$%^&*()_+\t\
\tQWERTYUIOP{}\t\
\tASDFGHJKL:\"\n\t\
\tZXCVBNM<>?\n\n\t\
\n\n\n\n\n\n\n\n\n\n\n\n\n\n";
    const char dvorakkeymap[] =
    "\n\n\n\n\n\n\n\n\n\n\n\n\n\n\
\t1234567890[]\t\
\t',.pyfgcrl/=\t\
\taoeuidhtns-\n\t\
\t;qjkxbmwvz\t\t\t\
\n\n\n\n\n\n\n\n\n\n\n\n\n\n\
\t!@#$%^&*(){}\t\
\t\"<>PYFGCRL?+\t\
\tAOEUIDHTNS_\n\t\
\t:QJKXBMWVZ\n\n\t\
\n\n\n\n\n\n\n\n\n\n\n\n\n\n";
    const char *keymap;
    if ( isset( DVORAK ) )
      keymap = dvorakkeymap;
    else
      keymap = qwertykeymap;

    if (!strcmp(s, t))
        return 0;
    /* any number of upper/lower mistakes allowed (dist = 1) */
    for (p = s, q = t; *p && tulower(*p) == tulower(*q); p++, q++);
    if (!*p && !*q)
        return 1;
    if (!thresh)
        return 200;
    for (p = s, q = t; *p && *q; p++, q++)
        if (*p == *q)
            continue;           /* don't consider "aa" transposed, ash */
        else if (p[1] == q[0] && q[1] == p[0])  /* transpositions */
            return spdist(p + 2, q + 2, thresh - 1) + 1;
        else if (p[1] == q[0])  /* missing letter */
            return spdist(p + 1, q + 0, thresh - 1) + 2;
        else if (p[0] == q[1])  /* missing letter */
            return spdist(p + 0, q + 1, thresh - 1) + 2;
        else if (*p != *q)
            break;
    if ((!*p && strlen(q) == 1) || (!*q && strlen(p) == 1))
        return 2;
    for (p = s, q = t; *p && *q; p++, q++)
        if (p[0] != q[0] && p[1] == q[1]) {
            int t0;
            char *z;

            /* mistyped letter */

            if (!(z = strchr(keymap, p[0])) || *z == '\n' || *z == '\t')
                return spdist(p + 1, q + 1, thresh - 1) + 1;
            t0 = z - keymap;
            if (*q == keymap[t0 - 15] || *q == keymap[t0 - 14] ||
                *q == keymap[t0 - 13] ||
                *q == keymap[t0 - 1] || *q == keymap[t0 + 1] ||
                *q == keymap[t0 + 13] || *q == keymap[t0 + 14] ||
                *q == keymap[t0 + 15])
                return spdist(p + 1, q + 1, thresh - 1) + 2;
            return 200;
        } else if (*p != *q)
            break;
    return 200;
}

/* set cbreak mode, or the equivalent */

/**/
void
setcbreak(void)
{
    struct ttyinfo ti;

    ti = shttyinfo;
#ifdef HAS_TIO
    ti.tio.c_lflag &= ~ICANON;
    ti.tio.c_cc[VMIN] = 1;
    ti.tio.c_cc[VTIME] = 0;
#else
    ti.sgttyb.sg_flags |= CBREAK;
#endif
    settyinfo(&ti);
}

/* give the tty to some process */

/**/
mod_export void
attachtty(pid_t pgrp)
{
    static int ep = 0;

    if (jobbing) {
#ifdef HAVE_TCSETPGRP
        if (SHTTY != -1 && tcsetpgrp(SHTTY, pgrp) == -1 && !ep)
#else
# if ardent
        if (SHTTY != -1 && setpgrp() == -1 && !ep)
# else
        int arg = pgrp;

        if (SHTTY != -1 && ioctl(SHTTY, TIOCSPGRP, &arg) == -1 && !ep)
# endif
#endif
        {
            if (pgrp != mypgrp && kill(-pgrp, 0) == -1)
                attachtty(mypgrp);
            else {
                if (errno != ENOTTY)
                {
                    zwarn("can't set tty pgrp: %e", errno);
                    fflush(stderr);
                }
                opts[MONITOR] = 0;
                ep = 1;
            }
        }
    }
}

/* get the process group associated with the tty */

/**/
pid_t
gettygrp(void)
{
    pid_t arg;

    if (SHTTY == -1)
        return -1;

#ifdef HAVE_TCSETPGRP
    arg = tcgetpgrp(SHTTY);
#else
    ioctl(SHTTY, TIOCGPGRP, &arg);
#endif

    return arg;
}


/* Escape tokens and null characters.  Buf is the string which should be     *
 * escaped.  len is the length of the string.  If len is -1, buf should be   *
 * null terminated.  If len is non-negative and the third parameter is not   *
 * META_DUP, buf should point to an at least len+1 long memory area.  The    *
 * return value points to the quoted string.  If the given string does not   *
 * contain any special character which should be quoted and the third        *
 * parameter is not META_(HEAP|)DUP, buf is returned unchanged (a            *
 * terminating null character is appended to buf if necessary).  Otherwise   *
 * the third `heap' argument determines the method used to allocate space    *
 * for the result.  It can have the following values:                        *
 *   META_REALLOC:  use zrealloc on buf                                      *
 *   META_HREALLOC: use hrealloc on buf                                      *
 *   META_USEHEAP:  get memory from the heap.  This leaves buf unchanged.    *
 *   META_NOALLOC:  buf points to a memory area which is long enough to hold *
 *                  the quoted form, just quote it and return buf.           *
 *   META_STATIC:   store the quoted string in a static area.  The original  *
 *                  string should be at most PATH_MAX long.                  *
 *   META_ALLOC:    allocate memory for the new string with zalloc().        *
 *   META_DUP:      leave buf unchanged and allocate space for the return    *
 *                  value even if buf does not contains special characters   *
 *   META_HEAPDUP:  same as META_DUP, but uses the heap                      */

/**/
mod_export char *
metafy(char *buf, int len, int heap)
{
    int meta = 0;
    char *t, *p, *e;
    static char mbuf[PATH_MAX*2+1];

    if (len == -1) {
        for (e = buf, len = 0; *e; len++)
            if (imeta(*e++))
                meta++;
    } else
        for (e = buf; e < buf + len;)
            if (imeta(*e++))
                meta++;

    if (meta || heap == META_DUP || heap == META_HEAPDUP) {
        switch (heap) {
        case META_REALLOC:
            buf = zrealloc(buf, len + meta + 1);
            break;
        case META_HREALLOC:
            buf = hrealloc(buf, len, len + meta + 1);
            break;
        case META_ALLOC:
        case META_DUP:
            buf = memcpy(zalloc(len + meta + 1), buf, len);
            break;
        case META_USEHEAP:
        case META_HEAPDUP:
            buf = memcpy(zhalloc(len + meta + 1), buf, len);
            break;
        case META_STATIC:
#ifdef DEBUG
            if (len > PATH_MAX) {
                fprintf(stderr, "BUG: len = %d > PATH_MAX in metafy\n", len);
                fflush(stderr);
            }
#endif
            buf = memcpy(mbuf, buf, len);
            break;
#ifdef DEBUG
        case META_NOALLOC:
            break;
        default:
            fprintf(stderr, "BUG: metafy called with invalid heap value\n");
            fflush(stderr);
            break;
#endif
        }
        p = buf + len;
        e = t = buf + len + meta;
        while (meta) {
            if (imeta(*--t = *--p)) {
                *t-- ^= 32;
                *t = Meta;
                meta--;
            }
        }
    }
    *e = '\0';
    return buf;
}


/*
 * Take a null-terminated, metafied string in s into a literal
 * representation by converting in place.  The length is in *len
 * len is non-NULL; if len is NULL, you don't know the length of
 * the final string, but if it's to be supplied to some system
 * routine that always uses NULL termination, such as a filename
 * interpreter, that doesn't matter.  Note the NULL termination
 * is always copied for purposes of that kind.
 */

/**/
mod_export char *
unmetafy(char *s, int *len)
{
    char *p, *t;

    for (p = s; *p && *p != Meta; p++);
    for (t = p; (*t = *p++);)
        if (*t++ == Meta)
            t[-1] = *p++ ^ 32;
    if (len)
        *len = t - s;
    return s;
}

/* Return the character length of a metafied substring, given the      *
 * unmetafied substring length.                                        */

/**/
mod_export int
metalen(const char *s, int len)
{
    int mlen = len;

    while (len--) {
        if (*s++ == Meta) {
            mlen++;
            s++;
        }
    }
    return mlen;
}

/*
 * This function converts a zsh internal string to a form which can be
 * passed to a system call as a filename.  The result is stored in a
 * single static area, sized to fit.  If there is no Meta character
 * the original string is returned.
 */

/**/
mod_export char *
unmeta(const char *file_name)
{
    static char *fn;
    static int sz;
    char *p;
    const char *t;
    int newsz, meta;
    
    meta = 0;
    for (t = file_name; *t; t++) {
        if (*t == Meta)
            meta = 1;
    }
    if (!meta) {
        /*
         * don't need allocation... free if it's long, see below
         */
        if (sz > 4 * PATH_MAX) {
            zfree(fn, sz);
            fn = NULL;
            sz = 0;
        }
        return (char *) file_name;
    }

    newsz = (t - file_name) + 1;
    /*
     * Optimisation: don't resize if we don't have to.
     * We need a new allocation if
     * - nothing was allocated before
     * - the new string is larger than the old one
     * - the old string was larger than an arbitrary limit but the
     *   new string isn't so that we free up significant space by resizing.
     */
    if (!fn || newsz > sz || (sz > 4 * PATH_MAX && newsz <= 4 * PATH_MAX))
    {
        if (fn)
            zfree(fn, sz);
        sz = newsz;
        fn = (char *)zalloc(sz);
        if (!fn) {
            sz = 0;
            /*
             * will quite likely crash in the caller anyway...
             */
            return NULL;
        }
    }

    for (t = file_name, p = fn; *t; p++)
        if ((*p = *t++) == Meta)
            *p = *t++ ^ 32;
    *p = '\0';
    return fn;
}

/*
 * Unmetafy and compare two strings, comparing unsigned character values.
 * "a\0" sorts after "a".
 *
 * Currently this is only used in hash table sorting, where the
 * keys are names of hash nodes and where we don't use strcoll();
 * it's not clear if that's right but it does guarantee the ordering
 * of shell structures on output.
 *
 * As we don't use strcoll(), it seems overkill to convert multibyte
 * characters to wide characters for comparison every time.  In the case
 * of UTF-8, Unicode ordering is preserved when sorted raw, and for
 * other character sets we rely on an extension of ASCII so the result,
 * while it may not be correct, is at least rational.
 */

/**/
int
ztrcmp(char const *s1, char const *s2)
{
    int c1, c2;

    while(*s1 && *s1 == *s2) {
        s1++;
        s2++;
    }

    if(!(c1 = *s1))
        c1 = -1;
    else if(c1 == STOUC(Meta))
        c1 = *++s1 ^ 32;
    if(!(c2 = *s2))
        c2 = -1;
    else if(c2 == STOUC(Meta))
        c2 = *++s2 ^ 32;

    if(c1 == c2)
        return 0;
    else if(c1 < c2)
        return -1;
    else
        return 1;
}

/* Return the unmetafied length of a metafied string. */

/**/
mod_export int
ztrlen(char const *s)
{
    int l;

    for (l = 0; *s; l++) {
        if (*s++ == Meta) {
#ifdef DEBUG
            if (! *s)
                fprintf(stderr, "BUG: unexpected end of string in ztrlen()\n");
            else
#endif
            s++;
        }
    }
    return l;
}

/* Subtract two pointers in a metafied string. */

/**/
mod_export int
ztrsub(char const *t, char const *s)
{
    int l = t - s;

    while (s != t) {
        if (*s++ == Meta) {
#ifdef DEBUG
            if (! *s || s == t)
                fprintf(stderr, "BUG: substring ends in the middle of a metachar in ztrsub()\n");
            else
#endif
            s++;
            l--;
        }
    }
    return l;
}

/**/
mod_export char *
zreaddir(DIR *dir, int ignoredots)
{
    struct dirent *de;

    do {
        de = readdir(dir);
        if(!de)
            return NULL;
    } while(ignoredots && de->d_name[0] == '.' &&
        (!de->d_name[1] || (de->d_name[1] == '.' && !de->d_name[2])));

    return metafy(de->d_name, -1, META_STATIC);
}

/* Unmetafy and output a string.  Tokens are skipped. */

/**/
mod_export int
zputs(char const *s, FILE *stream)
{
    int c;

    while (*s) {
        if (*s == Meta)
            c = *++s ^ 32;
        else if(itok(*s)) {
            s++;
            continue;
        } else
            c = *s;
        s++;
        if (fputc(c, stream) < 0)
            return EOF;
    }
    return 0;
}

#ifndef MULTIBYTE_SUPPORT
/* Create a visibly-represented duplicate of a string. */

/**/
mod_export char *
nicedup(char const *s, int heap)
{
    int c, len = strlen(s) * 5 + 1;
    VARARR(char, buf, len);
    char *p = buf, *n;

    while ((c = *s++)) {
        if (itok(c)) {
            if (c <= Comma)
                c = ztokens[c - Pound];
            else
                continue;
        }
        if (c == Meta)
            c = *s++ ^ 32;
        /* The result here is metafied */
        n = nicechar(c);
        while(*n)
            *p++ = *n++;
    }
    *p = '\0';
    return heap ? dupstring(buf) : ztrdup(buf);
}
#endif

/**/
mod_export char *
nicedupstring(char const *s)
{
    return nicedup(s, 1);
}


#ifndef MULTIBYTE_SUPPORT
/* Unmetafy and output a string, displaying special characters readably. */

/**/
mod_export int
nicezputs(char const *s, FILE *stream)
{
    int c;

    while ((c = *s++)) {
        if (itok(c)) {
            if (c <= Comma)
                c = ztokens[c - Pound];
            else
                continue;
        }
        if (c == Meta)
            c = *s++ ^ 32;
        if(zputs(nicechar(c), stream) < 0)
            return EOF;
    }
    return 0;
}


/* Return the length of the visible representation of a metafied string. */

/**/
mod_export size_t
niceztrlen(char const *s)
{
    size_t l = 0;
    int c;

    while ((c = *s++)) {
        if (itok(c)) {
            if (c <= Comma)
                c = ztokens[c - Pound];
            else
                continue;
        }
        if (c == Meta)
            c = *s++ ^ 32;
        l += strlen(nicechar(c));
    }
    return l;
}
#endif


/**/
#ifdef MULTIBYTE_SUPPORT
/*
 * Version of both nicezputs() and niceztrlen() for use with multibyte
 * characters.  Input is a metafied string; output is the screen width of
 * the string.
 *
 * If the FILE * is not NULL, output to that, too.
 *
 * If outstrp is not NULL, set *outstrp to a zalloc'd version of
 * the output (still metafied).
 *
 * If "heap" is non-zero, use the heap for *outstrp, else zalloc.
 */

/**/
mod_export size_t
mb_niceformat(const char *s, FILE *stream, char **outstrp, int heap)
{
    size_t l = 0, newl;
    int umlen, outalloc, outleft, eol = 0;
    wchar_t c;
    char *ums, *ptr, *fmt, *outstr, *outptr;
    mbstate_t mbs;

    if (outstrp) {
        outleft = outalloc = 5 * strlen(s);
        outptr = outstr = zalloc(outalloc);
    } else {
        outleft = outalloc = 0;
        outptr = outstr = NULL;
    }

    ums = ztrdup(s);
    /*
     * is this necessary at this point? niceztrlen does this
     * but it's used in lots of places.  however, one day this may
     * be, too.
     */
    untokenize(ums);
    ptr = unmetafy(ums, &umlen);

    memset(&mbs, 0, sizeof mbs);
    while (umlen > 0) {
        size_t cnt = eol ? MB_INVALID : mbrtowc(&c, ptr, umlen, &mbs);

        switch (cnt) {
        case MB_INCOMPLETE:
            eol = 1;
            /* FALL THROUGH */
        case MB_INVALID:
            /* The byte didn't convert, so output it as a \M-... sequence. */
            fmt = nicechar(*ptr);
            newl = strlen(fmt);
            cnt = 1;
            /* Get mbs out of its undefined state. */
            memset(&mbs, 0, sizeof mbs);
            break;
        case 0:
            /* Careful:  converting '\0' returns 0, but a '\0' is a
             * real character for us, so we should consume 1 byte. */
            cnt = 1;
            /* FALL THROUGH */
        default:
            fmt = wcs_nicechar(c, &newl, NULL);
            break;
        }

        umlen -= cnt;
        ptr += cnt;
        l += newl;

        if (stream)
            zputs(fmt, stream);
        if (outstr) {
            /* Append to output string */
            int outlen = strlen(fmt);
            if (outlen >= outleft) {
                /* Reallocate to twice the length */
                int outoffset = outptr - outstr;

                outleft += outalloc;
                outalloc *= 2;
                outstr = zrealloc(outstr, outalloc);
                outptr = outstr + outoffset;
            }
            memcpy(outptr, fmt, outlen);
            /* Update start position */
            outptr += outlen;
            /* Update available bytes */
            outleft -= outlen;
        }
    }

    free(ums);
    if (outstrp) {
        *outptr = '\0';
        /* Use more efficient storage for returned string */
        *outstrp = heap ? dupstring(outstr) : ztrdup(outstr);
        free(outstr);
    }

    return l;
}

/* ztrdup multibyte string with nice formatting */

/**/
mod_export char *
nicedup(const char *s, int heap)
{
    char *retstr;

    (void)mb_niceformat(s, NULL, &retstr, heap);

    return retstr;
}


/*
 * The guts of mb_metacharlenconv().  This version assumes we are
 * processing a true multibyte character string without tokens, and
 * takes the shift state as an argument.
 */

/**/
mod_export int
mb_metacharlenconv_r(const char *s, wint_t *wcp, mbstate_t *mbsp)
{
    size_t ret = MB_INVALID;
    char inchar;
    const char *ptr;
    wchar_t wc;

    for (ptr = s; *ptr; ) {
        if (*ptr == Meta) {
            inchar = *++ptr ^ 32;
            DPUTS(!*ptr,
                  "BUG: unexpected end of string in mb_metacharlen()\n");
        } else
            inchar = *ptr;
        ptr++;
        ret = mbrtowc(&wc, &inchar, 1, mbsp);

        if (ret == MB_INVALID)
            break;
        if (ret == MB_INCOMPLETE)
            continue;
        if (wcp)
            *wcp = wc;
        return ptr - s;
    }

    if (wcp)
        *wcp = WEOF;
    /* No valid multibyte sequence */
    memset(mbsp, 0, sizeof(*mbsp));
    if (ptr > s) {
        return 1 + (*s == Meta);        /* Treat as single byte character */
    } else
        return 0;               /* Probably shouldn't happen */
}

/*
 * Length of metafied string s which contains the next multibyte
 * character; single (possibly metafied) character if string is not null
 * but character is not valid (e.g. possibly incomplete at end of string).
 * Returned value is guaranteed not to reach beyond the end of the
 * string (assuming correct metafication).
 *
 * If wcp is not NULL, the converted wide character is stored there.
 * If no conversion could be done WEOF is used.
 */

/**/
mod_export int
mb_metacharlenconv(const char *s, wint_t *wcp)
{
    if (!isset(MULTIBYTE)) {
        /* treat as single byte, possibly metafied */
        if (wcp)
            *wcp = (wint_t)(*s == Meta ? s[1] ^ 32 : *s);
        return 1 + (*s == Meta);
    }
    /*
     * We have to handle tokens here, since we may be looking
     * through a tokenized input.  Obviously this isn't
     * a valid multibyte character, so just return WEOF
     * and let the caller handle it as a single character.
     *
     * TODO: I've a sneaking suspicion we could do more here
     * to prevent the caller always needing to handle invalid
     * characters specially, but sometimes it may need to know.
     */
    if (itok(*s)) {
        if (wcp)
            *wcp = WEOF;
        return 1;
    }

    return mb_metacharlenconv_r(s, wcp, &mb_shiftstate);
}

/*
 * Total number of multibyte characters in metafied string s.
 * Same answer as iterating mb_metacharlen() and counting calls
 * until end of string.
 *
 * If width is 1, return total character width rather than number.
 */

/**/
mod_export int
mb_metastrlen(char *ptr, int width)
{
    char inchar, *laststart;
    size_t ret;
    wchar_t wc;
    int num, num_in_char;

    if (!isset(MULTIBYTE))
        return ztrlen(ptr);

    laststart = ptr;
    ret = MB_INVALID;
    num = num_in_char = 0;

    memset(&mb_shiftstate, 0, sizeof(mb_shiftstate));
    while (*ptr) {
        if (*ptr == Meta)
            inchar = *++ptr ^ 32;
        else
            inchar = *ptr;
        ptr++;
        ret = mbrtowc(&wc, &inchar, 1, &mb_shiftstate);

        if (ret == MB_INCOMPLETE) {
            num_in_char++;
        } else {
            if (ret == MB_INVALID) {
                /* Reset, treat as single character */
                memset(&mb_shiftstate, 0, sizeof(mb_shiftstate));
                ptr = laststart + (*laststart == Meta) + 1;
                num++;
            } else if (width) {
                /*
                 * Returns -1 if not a printable character.  We
                 * turn this into 1 for backward compatibility.
                 */
                int wcw = WCWIDTH(wc);
                if (wcw >= 0)
                    num += wcw;
                else
                    num++;
            } else
                num++;
            laststart = ptr;
            num_in_char = 0;
        }
    }

    /* If incomplete, treat remainder as trailing single bytes */
    return num + num_in_char;
}

/**/
#else

/* Simple replacement for mb_metacharlenconv */

/**/
mod_export int
metacharlenconv(const char *x, int *c)
{
    /*
     * Here we don't use STOUC() on the chars since they
     * may be compared against other chars and this will fail
     * if chars are signed and the high bit is set.
     */
    if (*x == Meta) {
        if (c)
            *c = x[1] ^ 32;
        return 2;
    }
    if (c)
        *c = (char)*x;
    return 1;
}

/**/
#endif /* MULTIBYTE_SUPPORT */

/* check for special characters in the string */

/**/
mod_export int
hasspecial(char const *s)
{
    for (; *s; s++) {
        if (ispecial(*s == Meta ? *++s ^ 32 : *s))
            return 1;
    }
    return 0;
}


static char *
addunprintable(char *v, const char *u, const char *uend)
{
    for (; u < uend; u++) {
        /*
         * Just do this byte by byte; there's no great
         * advantage in being clever with multibyte
         * characters if we don't think they're printable.
         */
        int c;
        if (*u == Meta)
            c = STOUC(*++u ^ 32);
        else
            c = STOUC(*u);
        switch (c) {
        case '\0':
            *v++ = '\\';
            *v++ = '0';
            if ('0' <= u[1] && u[1] <= '7') {
                *v++ = '0';
                *v++ = '0';
            }
            break;

        case '\007': *v++ = '\\'; *v++ = 'a'; break;
        case '\b': *v++ = '\\'; *v++ = 'b'; break;
        case '\f': *v++ = '\\'; *v++ = 'f'; break;
        case '\n': *v++ = '\\'; *v++ = 'n'; break;
        case '\r': *v++ = '\\'; *v++ = 'r'; break;
        case '\t': *v++ = '\\'; *v++ = 't'; break;
        case '\v': *v++ = '\\'; *v++ = 'v'; break;

        default:
            *v++ = '\\';
            *v++ = '0' + ((c >> 6) & 7);
            *v++ = '0' + ((c >> 3) & 7);
            *v++ = '0' + (c & 7);
            break;
        }
    }

    return v;
}

/*
 * Quote the string s and return the result.
 *
 * If e is non-zero, the
 * pointer it points to may point to a position in s and in e the position
 * of the corresponding character in the quoted string is returned.
 * 
 * The last argument is a QT_ value defined in zsh.h other than QT_NONE.
 *
 * The string may be metafied and contain tokens.
 */

/**/
mod_export char *
quotestring(const char *s, char **e, int instring)
{
    const char *u, *tt;
    char *v;
    /*
     * With QT_BACKSLASH we may need to use $'\300' stuff.
     * Keep memory usage within limits by allocating temporary
     * storage and using heap for correct size at end.
     */
    int alloclen = (instring == QT_BACKSLASH ? 7 : 4) * strlen(s) + 1;
    char *buf = zshcalloc(alloclen);
    int sf = 0;
    convchar_t cc;
    const char *uend;

    DPUTS(instring < QT_BACKSLASH || instring > QT_DOLLARS,
          "BUG: bad quote type in quotestring");
    tt = v = buf;
    u = s;
    if (instring == QT_DOLLARS) {
        /*
         * As we test for printability here we need to be able
         * to look for multibyte characters.
         */
        MB_METACHARINIT();
        while (*u) {
            uend = u + MB_METACHARLENCONV(u, &cc);

            if (e && !sf && *e <= u) {
                *e = v;
                sf = 1;
            }
            if (
#ifdef MULTIBYTE_SUPPORT
                cc != WEOF &&
#endif
                WC_ISPRINT(cc)) {
                switch (cc) {
                case ZWC('\\'):
                case ZWC('\''):
                    *v++ = '\\';
                    break;

                default:
                    if (isset(BANGHIST) && cc == (wchar_t)bangchar)
                        *v++ = '\\';
                    break;
                }
                while (u < uend)
                    *v++ = *u++;
            } else {
                /* Not printable */
                v = addunprintable(v, u, uend);
                u = uend;
            }
        }
    }
    else
    {
        /*
         * Here there are syntactic special characters, so
         * we start by going through bytewise.
         */
        while (*u) {
            int dobackslash = 0;
            if (e && *e == u)
                *e = v, sf = 1;
            if (*u == Tick || *u == Qtick) {
                char c = *u++;

                *v++ = c;
                while (*u && *u != c)
                    *v++ = *u++;
                *v++ = c;
                if (*u)
                    u++;
                continue;
            } else if ((*u == Qstring || *u == '$') && u[1] == '\'' &&
                       instring == QT_DOUBLE) {
                /*
                 * We don't need to quote $'...' inside a double-quoted
                 * string.  This is largely cosmetic; it looks neater
                 * if we don't but it doesn't do any harm since the
                 * \ is stripped.
                 */
                *v++ = *u++;
            } else if ((*u == String || *u == Qstring) &&
                       (u[1] == Inpar || u[1] == Inbrack || u[1] == Inbrace)) {
                char c = (u[1] == Inpar ? Outpar : (u[1] == Inbrace ?
                                                    Outbrace : Outbrack));
                char beg = *u;
                int level = 0;

                *v++ = *u++;
                *v++ = *u++;
                while (*u && (*u != c || level)) {
                    if (*u == beg)
                        level++;
                    else if (*u == c)
                        level--;
                    *v++ = *u++;
                }
                if (*u)
                    *v++ = *u++;
                continue;
            }
            else if (ispecial(*u) &&
                     ((*u != '=' && *u != '~') ||
                      u == s ||
                      (isset(MAGICEQUALSUBST) &&
                       (u[-1] == '=' || u[-1] == ':')) ||
                      (*u == '~' && isset(EXTENDEDGLOB))) &&
                     (instring == QT_BACKSLASH ||
                      (isset(BANGHIST) && *u == (char)bangchar &&
                       instring != QT_SINGLE) ||
                      (instring == QT_DOUBLE &&
                       (*u == '$' || *u == '`' || *u == '\"' || *u == '\\')) ||
                      (instring == QT_SINGLE && *u == '\''))) {
                if (*u == '\n' || (instring == QT_SINGLE && *u == '\'')) {
                    if (unset(RCQUOTES)) {
                        *v++ = '\'';
                        if (*u == '\'')
                            *v++ = '\\';
                        *v++ = *u;
                        *v++ = '\'';
                    } else if (*u == '\n')
                        *v++ = '"', *v++ = '\n', *v++ = '"';
                    else
                        *v++ = '\'', *v++ = '\'';
                    u++;
                    continue;
                } else {
                    /*
                     * We'll need a backslash, but don't add it
                     * yet since if the character isn't printable
                     * we'll have to upgrade it to $'...'.
                     */
                    dobackslash = 1;
                }
            }

            if (itok(*u) || instring != QT_BACKSLASH) {
                /* Needs to be passed straight through. */
                if (dobackslash)
                    *v++ = '\\';
                *v++ = *u++;
                continue;
            }

            /*
             * Now check if the output is unprintable in the
             * current character set.
             */
            uend = u + MB_METACHARLENCONV(u, &cc);
            if (
#ifdef MULTIBYTE_SUPPORT
                cc != WEOF &&
#endif
                WC_ISPRINT(cc)) {
                if (dobackslash)
                    *v++ = '\\';
                while (u < uend) {
                    if (*u == Meta)
                        *v++ = *u++;
                    *v++ = *u++;
                }
            } else {
                /* Not printable */
                *v++ = '$';
                *v++ = '\'';
                v = addunprintable(v, u, uend);
                *v++ = '\'';
                u = uend;
            }
        }
    }
    *v = '\0';

    if (e && *e == u)
        *e = v, sf = 1;
    DPUTS(e && !sf, "BUG: Wild pointer *e in quotestring()");

    v = dupstring(buf);
    zfree(buf, alloclen);
    return v;
}

/* Unmetafy and output a string, quoted if it contains special characters. */

/**/
mod_export int
quotedzputs(char const *s, FILE *stream)
{
    int inquote = 0, c;

    /* check for empty string */
    if(!*s)
        return fputs("''", stream);

    if (!hasspecial(s))
        return zputs(s, stream);

    if (isset(RCQUOTES)) {
        /* use rc-style quotes-within-quotes for the whole string */
        if(fputc('\'', stream) < 0)
            return EOF;
        while(*s) {
            if (*s == Meta)
                c = *++s ^ 32;
            else
                c = *s;
            s++;
            if (c == '\'') {
                if(fputc('\'', stream) < 0)
                    return EOF;
            } else if(c == '\n' && isset(CSHJUNKIEQUOTES)) {
                if(fputc('\\', stream) < 0)
                    return EOF;
            }
            if(fputc(c, stream) < 0)
                return EOF;
        }
        if(fputc('\'', stream) < 0)
            return EOF;
    } else {
        /* use Bourne-style quoting, avoiding empty quoted strings */
        while(*s) {
            if (*s == Meta)
                c = *++s ^ 32;
            else
                c = *s;
            s++;
            if (c == '\'') {
                if(inquote) {
                    if(fputc('\'', stream) < 0)
                        return EOF;
                    inquote=0;
                }
                if(fputs("\\'", stream) < 0)
                    return EOF;
            } else {
                if (!inquote) {
                    if(fputc('\'', stream) < 0)
                        return EOF;
                    inquote=1;
                }
                if(c == '\n' && isset(CSHJUNKIEQUOTES)) {
                    if(fputc('\\', stream) < 0)
                        return EOF;
                }
                if(fputc(c, stream) < 0)
                    return EOF;
            }
        }
        if (inquote) {
            if(fputc('\'', stream) < 0)
                return EOF;
        }
    }
    return 0;
}

/* Double-quote a metafied string. */

/**/
mod_export char *
dquotedztrdup(char const *s)
{
    int len = strlen(s) * 4 + 2;
    char *buf = zalloc(len);
    char *p = buf, *ret;

    if(isset(CSHJUNKIEQUOTES)) {
        int inquote = 0;

        while(*s) {
            int c = *s++;

            if (c == Meta)
                c = *s++ ^ 32;
            switch(c) {
                case '"':
                case '$':
                case '`':
                    if(inquote) {
                        *p++ = '"';
                        inquote = 0;
                    }
                    *p++ = '\\';
                    *p++ = c;
                    break;
                default:
                    if(!inquote) {
                        *p++ = '"';
                        inquote = 1;
                    }
                    if(c == '\n')
                        *p++ = '\\';
                    *p++ = c;
                    break;
            }
        }
        if (inquote)
            *p++ = '"';
    } else {
        int pending = 0;

        *p++ = '"';
        while(*s) {
            int c = *s++;

            if (c == Meta)
                c = *s++ ^ 32;
            switch(c) {
                case '\\':
                    if(pending)
                        *p++ = '\\';
                    *p++ = '\\';
                    pending = 1;
                    break;
                case '"':
                case '$':
                case '`':
                    if(pending)
                        *p++ = '\\';
                    *p++ = '\\';
                    /* FALL THROUGH */
                default:
                    *p++ = c;
                    pending = 0;
                    break;
            }
        }
        if(pending)
            *p++ = '\\';
        *p++ = '"';
    }
    ret = metafy(buf, p - buf, META_DUP);
    zfree(buf, len);
    return ret;
}

/* Unmetafy and output a string, double quoting it in its entirety. */

#if 0 /**/
int
dquotedzputs(char const *s, FILE *stream)
{
    char *d = dquotedztrdup(s);
    int ret = zputs(d, stream);

    zsfree(d);
    return ret;
}
#endif

# if defined(HAVE_NL_LANGINFO) && defined(CODESET) && !defined(__STDC_ISO_10646__)
/* Convert a character from UCS4 encoding to UTF-8 */

static size_t
ucs4toutf8(char *dest, unsigned int wval)
{
    size_t len;

    if (wval < 0x80)
      len = 1;
    else if (wval < 0x800)
      len = 2;
    else if (wval < 0x10000)
      len = 3;
    else if (wval < 0x200000)
      len = 4;
    else if (wval < 0x4000000)
      len = 5;
    else
      len = 6;

    switch (len) { /* falls through except to the last case */
    case 6: dest[5] = (wval & 0x3f) | 0x80; wval >>= 6;
    case 5: dest[4] = (wval & 0x3f) | 0x80; wval >>= 6;
    case 4: dest[3] = (wval & 0x3f) | 0x80; wval >>= 6;
    case 3: dest[2] = (wval & 0x3f) | 0x80; wval >>= 6;
    case 2: dest[1] = (wval & 0x3f) | 0x80; wval >>= 6;
        *dest = wval | ((0xfc << (6 - len)) & 0xfc);
        break;
    case 1: *dest = wval;
    }

    return len;
}
#endif


/*
 * The following only occurs once or twice in the code, but in different
 * places depending how character set conversion is implemented.
 */
#define CHARSET_FAILED()                      \
    if (how & GETKEY_DOLLAR_QUOTE) {          \
        while ((*tdest++ = *++s)) {           \
            if (how & GETKEY_UPDATE_OFFSET) { \
                if (s - sstart > *misc)       \
                    (*misc)++;                \
            }                                 \
            if (*s == Snull) {                \
                *len = (s - sstart) + 1;      \
                *tdest = '\0';                \
                return buf;                   \
            }                                 \
        }                                     \
        *len = tdest - buf;                   \
        return buf;                           \
    }                                         \
    *t = '\0';                                \
    *len = t - buf;                           \
    return buf

/*
 * Decode a key string, turning it into the literal characters.
 * The value returned is a newly allocated string from the heap.
 *
 * The length is returned in *len.  This is usually the length of
 * the final unmetafied string.  The exception is the case of
 * a complete GETKEY_DOLLAR_QUOTE conversion where *len is the
 * length of the input string which has been used (up to and including
 * the terminating single quote); as the final string is metafied and
 * NULL-terminated its length is not required.  If both GETKEY_DOLLAR_QUOTE
 * and GETKEY_UPDATE_OFFSET are present in "how", the string is not
 * expected to be terminated (this is used in completion to parse
 * a partial $'...'-quoted string) and the length passed back is
 * that of the converted string.  Note in both cases that this is a length
 * in bytes (i.e. the same as given by a raw pointer difference), not
 * characters, which may occupy multiple bytes.
 *
 * how is a set of bits from the GETKEY_ values defined in zsh.h;
 * not all combinations of bits are useful.  Callers will typically
 * use one of the GETKEYS_ values which define sets of bits.
 * Note, for example that:
 * - GETKEY_SINGLE_CHAR must not be combined with GETKEY_DOLLAR_QUOTE.
 * - GETKEY_UPDATE_OFFSET is only allowed if GETKEY_DOLLAR_QUOTE is
 *   also present.
 *
 * *misc is used for various purposes:
 * - If GETKEY_BACKSLASH_MINUS is set, it indicates the presence
 *   of \- in the input.
 * - If GETKEY_BACKSLASH_C is set, it indicates the presence
 *   of \c in the input.
 * - If GETKEY_UPDATE_OFFSET is set, it is set on input to some
 *   mystical completion offset and is updated to a new offset based
 *   on the converted characters.  All Hail the Completion System
 *   [makes the mystic completion system runic sign in the air].
 *
 * The return value is unmetafied unless GETKEY_DOLLAR_QUOTE is
 * in use.
 */

/**/
mod_export char *
getkeystring(char *s, int *len, int how, int *misc)
{
    char *buf, tmp[1];
    char *t, *tdest = NULL, *u = NULL, *sstart = s, *tbuf = NULL;
    char svchar = '\0';
    int meta = 0, control = 0;
    int i;
#if defined(HAVE_WCHAR_H) && defined(HAVE_WCTOMB) && defined(__STDC_ISO_10646__)
    wint_t wval;
    int count;
#else
    unsigned int wval;
# if defined(HAVE_NL_LANGINFO) && defined(CODESET)
#  if defined(HAVE_ICONV)
    iconv_t cd;
    char inbuf[4];
    size_t inbytes, outbytes;
#  endif
    size_t count;
# endif
#endif

    DPUTS((how & GETKEY_UPDATE_OFFSET) &&
          (how & ~(GETKEYS_DOLLARS_QUOTE|GETKEY_UPDATE_OFFSET)),
          "BUG: offset updating in getkeystring only supported with $'.");
    DPUTS((how & (GETKEY_DOLLAR_QUOTE|GETKEY_SINGLE_CHAR)) ==
          (GETKEY_DOLLAR_QUOTE|GETKEY_SINGLE_CHAR),
          "BUG: incompatible options in getkeystring");

    if (how & GETKEY_SINGLE_CHAR)
        t = buf = tmp;
    else {
        /* Length including terminating NULL */
        int maxlen = 1;
        /*
         * We're not necessarily guaranteed the output string will
         * be no longer than the input with \u and \U when output
         * characters need to be metafied.  As this is the only
         * case where the string can get longer (?I think),
         * include it in the allocation length here but don't
         * bother taking account of other factors.
         */
        for (t = s; *t; t++) {
            if (*t == '\\') {
                if (!t[1]) {
                    maxlen++;
                    break;
                }
                if (t[1] == 'u' || t[1] == 'U')
                    maxlen += MB_CUR_MAX * 2;
                else
                    maxlen += 2;
                /* skip the backslash and the following character */
                t++;
            } else
                maxlen++;
        }
        if (how & GETKEY_DOLLAR_QUOTE) {
            /*
             * We're going to unmetafy into a new string, but
             * to get a proper metafied input we're going to metafy
             * into an intermediate buffer.  This is necessary if we have
             * \u and \U's with multiple metafied bytes.  We can't
             * simply remetafy the entire string because there may
             * be tokens (indeed, we know there are lexical nulls floating
             * around), so we have to be aware character by character
             * what we are converting.
             *
             * In this case, buf is the final buffer (as usual),
             * but t points into a temporary buffer that just has
             * to be long enough to hold the result of one escape
             * code transformation.  We count this is a full multibyte
             * character (MB_CUR_MAX) with every character metafied
             * (*2) plus a little bit of fuzz (for e.g. the odd backslash).
             */
            buf = tdest = zhalloc(maxlen);
            t = tbuf = zhalloc(MB_CUR_MAX * 3 + 1);
        } else {
            t = buf = zhalloc(maxlen);
        }
    }
    for (; *s; s++) {
        if (*s == '\\' && s[1]) {
            int miscadded;
            if ((how & GETKEY_UPDATE_OFFSET) && s - sstart < *misc) {
                (*misc)--;
                miscadded = 1;
            } else
                miscadded = 0;
            switch (*++s) {
            case 'a':
#ifdef __STDC__
                *t++ = '\a';
#else
                *t++ = '\07';
#endif
                break;
            case 'n':
                *t++ = '\n';
                break;
            case 'b':
                *t++ = '\b';
                break;
            case 't':
                *t++ = '\t';
                break;
            case 'v':
                *t++ = '\v';
                break;
            case 'f':
                *t++ = '\f';
                break;
            case 'r':
                *t++ = '\r';
                break;
            case 'E':
                if (!(how & GETKEY_EMACS)) {
                    *t++ = '\\', s--;
                    if (miscadded)
                        (*misc)++;
                    continue;
                }
                /* FALL THROUGH */
            case 'e':
                *t++ = '\033';
                break;
            case 'M':
                /* HERE: GETKEY_UPDATE_OFFSET */
                if (how & GETKEY_EMACS) {
                    if (s[1] == '-')
                        s++;
                    meta = 1 + control; /* preserve the order of ^ and meta */
                } else {
                    if (miscadded)
                        (*misc)++;
                    *t++ = '\\', s--;
                }
                continue;
            case 'C':
                /* HERE: GETKEY_UPDATE_OFFSET */
                if (how & GETKEY_EMACS) {
                    if (s[1] == '-')
                        s++;
                    control = 1;
                } else {
                    if (miscadded)
                        (*misc)++;
                    *t++ = '\\', s--;
                }
                continue;
            case Meta:
                if (miscadded)
                    (*misc)++;
                *t++ = '\\', s--;
                break;
            case '-':
                if (how & GETKEY_BACKSLASH_MINUS) {
                    *misc  = 1;
                    break;
                }
                goto def;
            case 'c':
                if (how & GETKEY_BACKSLASH_C) {
                    *misc = 1;
                    *t = '\0';
                    *len = t - buf;
                    return buf;
                }
                goto def;
            case 'U':
                if ((how & GETKEY_UPDATE_OFFSET) && s - sstart < *misc)
                    (*misc) -= 4;
                /* FALLTHROUGH */
            case 'u':
                if ((how & GETKEY_UPDATE_OFFSET) && s - sstart < *misc) {
                    (*misc) -= 6; /* HERE don't really believe this */
                    /*
                     * We've now adjusted the offset for all the input
                     * characters, so we need to add for each
                     * byte of output below.
                     */
                }
                wval = 0;
                for (i=(*s == 'u' ? 4 : 8); i>0; i--) {
                    if (*++s && idigit(*s))
                        wval = wval * 16 + (*s - '0');
                    else if (*s && ((*s >= 'a' && *s <= 'f') ||
                                    (*s >= 'A' && *s <= 'F')))
                        wval = wval * 16 + (*s & 0x1f) + 9;
                    else {
                        s--;
                        break;
                    }
                }
                if (how & GETKEY_SINGLE_CHAR) {
                    *misc = wval;
                    return s+1;
                }
#if defined(HAVE_WCHAR_H) && defined(HAVE_WCTOMB) && defined(__STDC_ISO_10646__)
                count = wctomb(t, (wchar_t)wval);
                if (count == -1) {
                    zerr("character not in range");
                    CHARSET_FAILED();
                }
                if ((how & GETKEY_UPDATE_OFFSET) && s - sstart < *misc)
                    (*misc) += count;
                t += count;
# else
#  if defined(HAVE_NL_LANGINFO) && defined(CODESET)
                if (!strcmp(nl_langinfo(CODESET), "UTF-8")) {
                    count = ucs4toutf8(t, wval);
                    t += count;
                    if ((how & GETKEY_UPDATE_OFFSET) && s - sstart < *misc)
                        (*misc) += count;
                } else {
#   ifdef HAVE_ICONV
                    ICONV_CONST char *inptr = inbuf;
                    const char *codesetstr = nl_langinfo(CODESET);
                    inbytes = 4;
                    outbytes = 6;
                    /* store value in big endian form */
                    for (i=3;i>=0;i--) {
                        inbuf[i] = wval & 0xff;
                        wval >>= 8;
                    }

                    /*
                     * If the code set isn't handled, we'd better
                     * assume it's US-ASCII rather than just failing
                     * hopelessly.  Solaris has a weird habit of
                     * returning 646.  This is handled by the
                     * native iconv(), but not by GNU iconv; what's
                     * more, some versions of the native iconv don't
                     * handle standard names like ASCII.
                     *
                     * This should only be a problem if there's a
                     * mismatch between the NLS and the iconv in use,
                     * which probably only means if libiconv is in use.
                     * We checked at configure time if our libraries
                     * pulled in _libiconv_version, which should be
                     * a good test.
                     *
                     * It shouldn't ever be NULL, but while we're
                     * being paranoid...
                     */
#ifdef ICONV_FROM_LIBICONV
                    if (!codesetstr || !*codesetstr)
                        codesetstr = "US-ASCII";
#endif
                    cd = iconv_open(codesetstr, "UCS-4BE");
#ifdef ICONV_FROM_LIBICONV
                    if (cd == (iconv_t)-1 &&  !strcmp(codesetstr, "646")) {
                        codesetstr = "US-ASCII";
                        cd = iconv_open(codesetstr, "UCS-4BE");
                    }
#endif
                    if (cd == (iconv_t)-1) {
                        zerr("cannot do charset conversion (iconv failed)");
                        CHARSET_FAILED();
                    }
                    count = iconv(cd, &inptr, &inbytes, &t, &outbytes);
                    iconv_close(cd);
                    if (count == (size_t)-1) {
                        zerr("character not in range");
                        CHARSET_FAILED();
                    }
                    if ((how & GETKEY_UPDATE_OFFSET) && s - sstart < *misc)
                        (*misc) += count;
#   else
                    zerr("cannot do charset conversion (iconv not available)");
                    CHARSET_FAILED();
#   endif
                }
#  else
                zerr("cannot do charset conversion (NLS not supported)");
                CHARSET_FAILED();
#  endif
# endif
                if (how & GETKEY_DOLLAR_QUOTE) {
                    char *t2;
                    for (t2 = tbuf; t2 < t; t2++) {
                        if (imeta(*t2)) {
                            *tdest++ = Meta;
                            *tdest++ = *t2 ^ 32;
                        } else
                            *tdest++ = *t2;
                    }
                    /* reset temporary buffer after handling */
                    t = tbuf;
                }
                continue;
            case '\'':
            case '\\':
                if (how & GETKEY_DOLLAR_QUOTE) {
                    /*
                     * Usually \' and \\ will have the initial
                     * \ turned into a Bnull, however that's not
                     * necessarily the case when called from
                     * completion.
                     */
                    *t++ = *s;
                    break;
                }
                /* FALLTHROUGH */
            default:
            def:
                /* HERE: GETKEY_UPDATE_OFFSET? */
                if ((idigit(*s) && *s < '8') || *s == 'x') {
                    if (!(how & GETKEY_OCTAL_ESC)) {
                        if (*s == '0')
                            s++;
                        else if (*s != 'x') {
                            *t++ = '\\', s--;
                            continue;
                        }
                    }
                    if (s[1] && s[2] && s[3]) {
                        svchar = s[3];
                        s[3] = '\0';
                        u = s;
                    }
                    *t++ = zstrtol(s + (*s == 'x'), &s,
                                   (*s == 'x') ? 16 : 8);
                    if (svchar) {
                        u[3] = svchar;
                        svchar = '\0';
                    }
                    s--;
                } else {
                    if (!(how & GETKEY_EMACS) && *s != '\\') {
                        if (miscadded)
                            (*misc)++;
                        *t++ = '\\';
                    }
                    *t++ = *s;
                }
                break;
            }
        } else if ((how & GETKEY_DOLLAR_QUOTE) && *s == Snull) {
            /* return length to following character */
            *len = (s - sstart) + 1;
            *tdest = '\0';
            return buf;
        } else if (*s == '^' && !control && (how & GETKEY_CTRL) && s[1]) {
            control = 1;
            continue;
#ifdef MULTIBYTE_SUPPORT
        } else if ((how & GETKEY_SINGLE_CHAR) &&
                   isset(MULTIBYTE) && STOUC(*s) > 127) {
            wint_t wc;
            int len;
            len = mb_metacharlenconv(s, &wc);
            if (wc != WEOF) {
                *misc = (int)wc;
                return s + len;
            }
#endif

        } else if (*s == Meta)
            *t++ = *++s ^ 32;
        else {
            if (itok(*s)) {
                /*
                 * We need to be quite careful here.  We haven't
                 * necessarily got an input stream with all tokens
                 * removed, so the majority of tokens need passing
                 * through untouched and without Meta handling.
                 * However, me may need to handle tokenized
                 * backslashes.
                 */
                if (meta || control) {
                    /*
                     * Presumably we should be using meta or control
                     * on the character representing the token.
                     *
                     * Special case: $'\M-\\' where the token is a Bnull.
                     * This time we dump the Bnull since we're
                     * replacing the whole thing.  The lexer
                     * doesn't know about the meta or control modifiers.
                     */
                    if ((how & GETKEY_DOLLAR_QUOTE) && *s == Bnull)
                        *t++ = *++s;
                    else
                        *t++ = ztokens[*s - Pound];
                } else if (how & GETKEY_DOLLAR_QUOTE) {
                    /*
                     * We don't want to metafy this, it's a real
                     * token.
                     */
                    *tdest++ = *s;
                    if (*s == Bnull) {
                        /*
                         * Bnull is a backslash which quotes a couple
                         * of special characters that always appear
                         * literally next.  See strquote handling
                         * in gettokstr() in lex.c.  We need
                         * to retain the Bnull (as above) so that quote
                         * handling in completion can tell where the
                         * backslash was.
                         */
                        *tdest++ = *++s;
                    }
                    /* reset temporary buffer, now handled */
                    t = tbuf;
                    continue;
                } else
                    *t++ = *s;
            } else
                *t++ = *s;
        }
        if (meta == 2) {
            t[-1] |= 0x80;
            meta = 0;
        }
        if (control) {
            if (t[-1] == '?')
                t[-1] = 0x7f;
            else
                t[-1] &= 0x9f;
            control = 0;
        }
        if (meta) {
            t[-1] |= 0x80;
            meta = 0;
        }
        if (how & GETKEY_DOLLAR_QUOTE) {
            char *t2;
            for (t2 = tbuf; t2 < t; t2++) {
                if (imeta(*t2)) {
                    *tdest++ = Meta;
                    *tdest++ = *t2 ^ 32;
                } else
                    *tdest++ = *t2;
            }
            /*
             * Reset use of temporary buffer.
             */
            t = tbuf;
        }
        if ((how & GETKEY_SINGLE_CHAR) && t != tmp) {
            *misc = STOUC(tmp[0]);
            return s + 1;
        }
    }
    /*
     * When called from completion, where we use GETKEY_UPDATE_OFFSET to
     * update the index into the metafied editor line, we don't necessarily
     * have the end of a $'...' quotation, else we should do.
     */
    DPUTS((how & (GETKEY_DOLLAR_QUOTE|GETKEY_UPDATE_OFFSET)) ==
          GETKEY_DOLLAR_QUOTE, "BUG: unterminated $' substitution");
    *t = '\0';
    if (how & GETKEY_DOLLAR_QUOTE)
        *tdest = '\0';
    if (how & GETKEY_SINGLE_CHAR)
        *misc = 0;
    else
        *len = ((how & GETKEY_DOLLAR_QUOTE) ? tdest : t) - buf;
    return buf;
}

/* Return non-zero if s is a prefix of t. */

/**/
mod_export int
strpfx(const char *s, const char *t)
{
    while (*s && *s == *t)
        s++, t++;
    return !*s;
}

/* Return non-zero if s is a suffix of t. */

/**/
mod_export int
strsfx(char *s, char *t)
{
    int ls = strlen(s), lt = strlen(t);

    if (ls <= lt)
        return !strcmp(t + lt - ls, s);
    return 0;
}

/**/
static int
upchdir(int n)
{
    char buf[PATH_MAX];
    char *s;
    int err = -1;

    while (n > 0) {
        for (s = buf; s < buf + PATH_MAX - 4 && n--; )
            *s++ = '.', *s++ = '.', *s++ = '/';
        s[-1] = '\0';
        if (chdir(buf))
            return err;
        err = -2;
    }
    return 0;
}

/* Change directory, without following symlinks.  Returns 0 on success, -1 *
 * on failure.  Sets errno to ENOTDIR if any symlinks are encountered.  If *
 * fchdir() fails, or the current directory is unreadable, we might end up *
 * in an unwanted directory in case of failure.                            */

/**/
mod_export int
lchdir(char const *path, struct dirsav *d, int hard)
{
    char const *pptr;
    int level;
    struct stat st1;
    struct dirsav ds;
#ifdef HAVE_LSTAT
    char buf[PATH_MAX + 1], *ptr;
    int err;
    struct stat st2;
#endif

    if (!d) {
        ds.ino = ds.dev = 0;
        ds.dirname = NULL;
        ds.dirfd = -1;
        d = &ds;
    }
#ifdef HAVE_LSTAT
    if ((*path == '/' || !hard) &&
        (d != &ds || hard)){
#else
    if (*path == '/') {
#endif
        level = -1;
#ifndef HAVE_FCHDIR
        if (!d->dirname)
            zgetdir(d);
#endif
    } else {
        level = 0;
        if (!d->dev && !d->ino) {
            stat(".", &st1);
            d->dev = st1.st_dev;
            d->ino = st1.st_ino;
        }
    }
#ifdef HAVE_FCHDIR
    if (d->dirfd < 0 && (d->dirfd = open(".", O_RDONLY | O_NOCTTY)) < 0 &&
        zgetdir(d) && *d->dirname != '/')
        d->dirfd = open("..", O_RDONLY | O_NOCTTY);
#endif

#ifdef HAVE_LSTAT
    if (!hard)
#endif
    {
        if (d != &ds) {
            for (pptr = path; *pptr; level++) {
                while (*pptr && *pptr++ != '/');
                while (*pptr == '/')
                    pptr++;
            }
            d->level = level;
        }
        return zchdir((char *) path);
    }
#ifdef HAVE_LSTAT
    if (*path == '/')
        if (chdir("/") < 0)
            zwarn("failed to chdir(/): %e", errno);
    for(;;) {
        while(*path == '/')
            path++;
        if(!*path) {
            if (d == &ds) {
                zsfree(ds.dirname);
                if (ds.dirfd >=0)
                    close(ds.dirfd);
            } else
                d->level = level;
            return 0;
        }
        for(pptr = path; *++pptr && *pptr != '/'; ) ;
        if(pptr - path > PATH_MAX) {
            err = ENAMETOOLONG;
            break;
        }
        for(ptr = buf; path != pptr; )
            *ptr++ = *path++;
        *ptr = 0;
        if(lstat(buf, &st1)) {
            err = errno;
            break;
        }
        if(!S_ISDIR(st1.st_mode)) {
            err = ENOTDIR;
            break;
        }
        if(chdir(buf)) {
            err = errno;
            break;
        }
        if (level >= 0)
            level++;
        if(lstat(".", &st2)) {
            err = errno;
            break;
        }
        if(st1.st_dev != st2.st_dev || st1.st_ino != st2.st_ino) {
            err = ENOTDIR;
            break;
        }
    }
    if (restoredir(d)) {
        if (d == &ds) {
            zsfree(ds.dirname);
            if (ds.dirfd >=0)
                close(ds.dirfd);
        }
        errno = err;
        return -2;
    }
    if (d == &ds) {
        zsfree(ds.dirname);
        if (ds.dirfd >=0)
            close(ds.dirfd);
    }
    errno = err;
    return -1;
#endif /* HAVE_LSTAT */
}

/**/
mod_export int
restoredir(struct dirsav *d)
{
    int err = 0;
    struct stat sbuf;

    if (d->dirname && *d->dirname == '/')
        return chdir(d->dirname);
#ifdef HAVE_FCHDIR
    if (d->dirfd >= 0) {
        if (!fchdir(d->dirfd)) {
            if (!d->dirname) {
                return 0;
            } else if (chdir(d->dirname)) {
                close(d->dirfd);
                d->dirfd = -1;
                err = -2;
            }
        } else {
            close(d->dirfd);
            d->dirfd = err = -1;
        }
    } else
#endif
    if (d->level > 0)
        err = upchdir(d->level);
    else if (d->level < 0)
        err = -1;
    if (d->dev || d->ino) {
        stat(".", &sbuf);
        if (sbuf.st_ino != d->ino || sbuf.st_dev != d->dev)
            err = -2;
    }
    return err;
}


/* Check whether the shell is running with privileges in effect.  *
 * This is the case if EITHER the euid is zero, OR (if the system *
 * supports POSIX.1e (POSIX.6) capability sets) the process'      *
 * Effective or Inheritable capability sets are non-empty.        */

/**/
int
privasserted(void)
{
    if(!geteuid())
        return 1;
#ifdef HAVE_CAP_GET_PROC
    {
        cap_t caps = cap_get_proc();
        if(caps) {
            /* POSIX doesn't define a way to test whether a capability set *
             * is empty or not.  Typical.  I hope this is conforming...    */
            cap_flag_value_t val;
            cap_value_t n;
            for(n = 0; !cap_get_flag(caps, n, CAP_EFFECTIVE, &val); n++)
                if(val) {
                    cap_free(caps);
                    return 1;
                }
            cap_free(caps);
        }
    }
#endif /* HAVE_CAP_GET_PROC */
    return 0;
}

/**/
mod_export int
mode_to_octal(mode_t mode)
{
    int m = 0;

    if(mode & S_ISUID)
        m |= 04000;
    if(mode & S_ISGID)
        m |= 02000;
    if(mode & S_ISVTX)
        m |= 01000;
    if(mode & S_IRUSR)
        m |= 00400;
    if(mode & S_IWUSR)
        m |= 00200;
    if(mode & S_IXUSR)
        m |= 00100;
    if(mode & S_IRGRP)
        m |= 00040;
    if(mode & S_IWGRP)
        m |= 00020;
    if(mode & S_IXGRP)
        m |= 00010;
    if(mode & S_IROTH)
        m |= 00004;
    if(mode & S_IWOTH)
        m |= 00002;
    if(mode & S_IXOTH)
        m |= 00001;
    return m;
}

#ifdef MAILDIR_SUPPORT
/*
 *     Stat a file. If it's a maildir, check all messages
 *     in the maildir and present the grand total as a file.
 *     The fields in the 'struct stat' are from the mail directory.
 *     The following fields are emulated:
 *
 *     st_nlink        always 1
 *     st_size         total number of bytes in all files
 *     st_blocks       total number of messages
 *     st_atime        access time of newest file in maildir
 *     st_mtime        modify time of newest file in maildir
 *     st_mode         S_IFDIR changed to S_IFREG
 *
 *     This is good enough for most mail-checking applications.
 */

/**/
int
mailstat(char *path, struct stat *st)
{
       DIR                     *dd;
       struct                  dirent *fn;
       struct stat             st_ret, st_tmp;
       static struct stat      st_ret_last;
       char                    *dir, *file = 0;
       int                     i;
       time_t                  atime = 0, mtime = 0;
       size_t                  plen = strlen(path), dlen;

       /* First see if it's a directory. */
       if ((i = stat(path, st)) != 0 || !S_ISDIR(st->st_mode))
               return i;

       st_ret = *st;
       st_ret.st_nlink = 1;
       st_ret.st_size  = 0;
       st_ret.st_blocks  = 0;
       st_ret.st_mode  &= ~S_IFDIR;
       st_ret.st_mode  |= S_IFREG;

       /* See if cur/ is present */
       dir = appstr(ztrdup(path), "/cur");
       if (stat(dir, &st_tmp) || !S_ISDIR(st_tmp.st_mode)) return 0;
       st_ret.st_atime = st_tmp.st_atime;

       /* See if tmp/ is present */
       dir[plen] = 0;
       dir = appstr(dir, "/tmp");
       if (stat(dir, &st_tmp) || !S_ISDIR(st_tmp.st_mode)) return 0;
       st_ret.st_mtime = st_tmp.st_mtime;

       /* And new/ */
       dir[plen] = 0;
       dir = appstr(dir, "/new");
       if (stat(dir, &st_tmp) || !S_ISDIR(st_tmp.st_mode)) return 0;
       st_ret.st_mtime = st_tmp.st_mtime;

#if THERE_IS_EXACTLY_ONE_MAILDIR_IN_MAILPATH
       {
       static struct stat      st_new_last;
       /* Optimization - if new/ didn't change, nothing else did. */
       if (st_tmp.st_dev == st_new_last.st_dev &&
           st_tmp.st_ino == st_new_last.st_ino &&
           st_tmp.st_atime == st_new_last.st_atime &&
           st_tmp.st_mtime == st_new_last.st_mtime) {
           *st = st_ret_last;
           return 0;
       }
       st_new_last = st_tmp;
       }
#endif

       /* Loop over new/ and cur/ */
       for (i = 0; i < 2; i++) {
           dir[plen] = 0;
           dir = appstr(dir, i ? "/cur" : "/new");
           if ((dd = opendir(dir)) == NULL) {
               zsfree(file);
               zsfree(dir);
               return 0;
           }
           dlen = strlen(dir) + 1; /* include the "/" */
           while ((fn = readdir(dd)) != NULL) {
               if (fn->d_name[0] == '.')
                   continue;
               if (file) {
                   file[dlen] = 0;
                   file = appstr(file, fn->d_name);
               } else {
                   file = tricat(dir, "/", fn->d_name);
               }
               if (stat(file, &st_tmp) != 0)
                   continue;
               st_ret.st_size += st_tmp.st_size;
               st_ret.st_blocks++;
               if (st_tmp.st_atime != st_tmp.st_mtime &&
                   st_tmp.st_atime > atime)
                   atime = st_tmp.st_atime;
               if (st_tmp.st_mtime > mtime)
                   mtime = st_tmp.st_mtime;
           }
           closedir(dd);
       }
       zsfree(file);
       zsfree(dir);

       if (atime) st_ret.st_atime = atime;
       if (mtime) st_ret.st_mtime = mtime;

       *st = st_ret_last = st_ret;
       return 0;
}
#endif