HAMMER VFS - Major retooling of the refcount mechanics, and fix a deadlock

[dragonfly.git] / lib / libedit / readline.c

/*-
 * Copyright (c) 1997 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jaromir Dolecek.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 * $NetBSD: readline.c,v 1.75 2008/04/29 06:53:01 martin Exp $
 * $DragonFly: src/lib/libedit/readline.c,v 1.5 2008/09/30 16:57:05 swildner Exp $
 */

#include "config.h"

#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include <dirent.h>
#include <string.h>
#include <pwd.h>
#include <ctype.h>
#include <stdlib.h>
#include <unistd.h>
#include <limits.h>
#include <errno.h>
#include <fcntl.h>
#include <setjmp.h>
#ifdef HAVE_VIS_H
#include <vis.h>
#else
#include "np/vis.h"
#endif
#ifdef HAVE_ALLOCA_H
#include <alloca.h>
#endif
#include "el.h"
#include "fcns.h"               /* for EL_NUM_FCNS */
#include "histedit.h"
#include "readline/readline.h"
#include "filecomplete.h"

void rl_prep_terminal(int);
void rl_deprep_terminal(void);

/* for rl_complete() */
#define TAB             '\r'

/* see comment at the #ifdef for sense of this */
/* #define GDB_411_HACK */

/* readline compatibility stuff - look at readline sources/documentation */
/* to see what these variables mean */
const char *rl_library_version = "EditLine wrapper";
static char empty[] = { '\0' };
static char expand_chars[] = { ' ', '\t', '\n', '=', '(', '\0' };
static char break_chars[] = { ' ', '\t', '\n', '"', '\\', '\'', '`', '@', '$',
    '>', '<', '=', ';', '|', '&', '{', '(', '\0' };
char *rl_readline_name = empty;
FILE *rl_instream = NULL;
FILE *rl_outstream = NULL;
int rl_point = 0;
int rl_end = 0;
char *rl_line_buffer = NULL;
VCPFunction *rl_linefunc = NULL;
int rl_done = 0;
VFunction *rl_event_hook = NULL;
KEYMAP_ENTRY_ARRAY emacs_standard_keymap,
    emacs_meta_keymap,
    emacs_ctlx_keymap;

int history_base = 1;           /* probably never subject to change */
int history_length = 0;
int max_input_history = 0;
char history_expansion_char = '!';
char history_subst_char = '^';
char *history_no_expand_chars = expand_chars;
Function *history_inhibit_expansion_function = NULL;
char *history_arg_extract(int start, int end, const char *str);

int rl_inhibit_completion = 0;
int rl_attempted_completion_over = 0;
char *rl_basic_word_break_characters = break_chars;
char *rl_completer_word_break_characters = NULL;
char *rl_completer_quote_characters = NULL;
char *(* rl_completion_word_break_hook)(void) = NULL;
Function *rl_completion_entry_function = NULL;
CPPFunction *rl_attempted_completion_function = NULL;
Function *rl_pre_input_hook = NULL;
Function *rl_startup1_hook = NULL;
int (*rl_getc_function)(FILE *) = NULL;
char *rl_terminal_name = NULL;
int rl_already_prompted = 0;
int rl_filename_completion_desired = 0;
int rl_ignore_completion_duplicates = 0;
int rl_catch_signals = 1;
int readline_echoing_p = 1;
int _rl_print_completions_horizontally = 0;
VFunction *rl_redisplay_function = NULL;
Function *rl_startup_hook = NULL;
VFunction *rl_completion_display_matches_hook = NULL;
VFunction *rl_prep_term_function = (VFunction *)rl_prep_terminal;
VFunction *rl_deprep_term_function = (VFunction *)rl_deprep_terminal;

/*
 * The current prompt string.
 */
char *rl_prompt = NULL;
/*
 * This is set to character indicating type of completion being done by
 * rl_complete_internal(); this is available for application completion
 * functions.
 */
int rl_completion_type = 0;

/*
 * If more than this number of items results from query for possible
 * completions, we ask user if they are sure to really display the list.
 */
int rl_completion_query_items = 100;

/*
 * List of characters which are word break characters, but should be left
 * in the parsed text when it is passed to the completion function.
 * Shell uses this to help determine what kind of completing to do.
 */
char *rl_special_prefixes = NULL;

/*
 * This is the character appended to the completed words if at the end of
 * the line. Default is ' ' (a space).
 */
int rl_completion_append_character = ' ';

/* stuff below is used internally by libedit for readline emulation */

static History *h = NULL;
static EditLine *e = NULL;
static Function *map[256];
static jmp_buf topbuf;

/* internal functions */
static unsigned char     _el_rl_complete(EditLine *, int);
static unsigned char     _el_rl_tstp(EditLine *, int);
static char             *_get_prompt(EditLine *);
static int               _getc_function(EditLine *, char *);
static HIST_ENTRY       *_move_history(int);
static int               _history_expand_command(const char *, size_t, size_t,
    char **);
static char             *_rl_compat_sub(const char *, const char *,
    const char *, int);
static int               _rl_event_read_char(EditLine *, char *);
static void              _rl_update_pos(void);


/* ARGSUSED */
static char *
_get_prompt(EditLine *el __attribute__((__unused__)))
{
        rl_already_prompted = 1;
        return (rl_prompt);
}


/*
 * generic function for moving around history
 */
static HIST_ENTRY *
_move_history(int op)
{
        HistEvent ev;
        static HIST_ENTRY rl_he;

        if (history(h, &ev, op) != 0)
                return NULL;

        rl_he.line = ev.str;
        rl_he.data = NULL;

        return (&rl_he);
}


/*
 * read one key from user defined input function
 */
static int
/*ARGSUSED*/
_getc_function(EditLine *el, char *c)
{
        int i;

        i = (*rl_getc_function)(NULL);
        if (i == -1)
                return 0;
        *c = i;
        return 1;
}


/*
 * READLINE compatibility stuff
 */

/*
 * initialize rl compat stuff
 */
int
rl_initialize(void)
{
        HistEvent ev;
        const LineInfo *li;
        int editmode = 1;
        struct termios t;

        if (e != NULL)
                el_end(e);
        if (h != NULL)
                history_end(h);

        if (!rl_instream)
                rl_instream = stdin;
        if (!rl_outstream)
                rl_outstream = stdout;

        /*
         * See if we don't really want to run the editor
         */
        if (tcgetattr(fileno(rl_instream), &t) != -1 && (t.c_lflag & ECHO) == 0)
                editmode = 0;

        e = el_init(rl_readline_name, rl_instream, rl_outstream, stderr);

        if (!editmode)
                el_set(e, EL_EDITMODE, 0);

        h = history_init();
        if (!e || !h)
                return (-1);

        history(h, &ev, H_SETSIZE, INT_MAX);    /* unlimited */
        history_length = 0;
        max_input_history = INT_MAX;
        el_set(e, EL_HIST, history, h);

        /* setup getc function if valid */
        if (rl_getc_function)
                el_set(e, EL_GETCFN, _getc_function);

        /* for proper prompt printing in readline() */
        rl_prompt = strdup("");
        if (rl_prompt == NULL) {
                history_end(h);
                el_end(e);
                return -1;
        }
        el_set(e, EL_PROMPT, _get_prompt);
        el_set(e, EL_SIGNAL, rl_catch_signals);

        /* set default mode to "emacs"-style and read setting afterwards */
        /* so this can be overriden */
        el_set(e, EL_EDITOR, "emacs");
        if (rl_terminal_name != NULL)
                el_set(e, EL_TERMINAL, rl_terminal_name);
        else
                el_get(e, EL_TERMINAL, &rl_terminal_name);

        /*
         * Word completion - this has to go AFTER rebinding keys
         * to emacs-style.
         */
        el_set(e, EL_ADDFN, "rl_complete",
            "ReadLine compatible completion function",
            _el_rl_complete);
        el_set(e, EL_BIND, "^I", "rl_complete", NULL);

        /*
         * Send TSTP when ^Z is pressed.
         */
        el_set(e, EL_ADDFN, "rl_tstp",
            "ReadLine compatible suspend function",
            _el_rl_tstp);
        el_set(e, EL_BIND, "^Z", "rl_tstp", NULL);
                
        /* read settings from configuration file */
        el_source(e, NULL);

        /*
         * Unfortunately, some applications really do use rl_point
         * and rl_line_buffer directly.
         */
        li = el_line(e);
        /* a cheesy way to get rid of const cast. */
        rl_line_buffer = memchr(li->buffer, *li->buffer, 1);
        _rl_update_pos();

        if (rl_startup_hook)
                (*rl_startup_hook)(NULL, 0);

        return (0);
}


/*
 * read one line from input stream and return it, chomping
 * trailing newline (if there is any)
 */
char *
readline(const char *p)
{
        HistEvent ev;
        const char * volatile prompt = p;
        int count;
        const char *ret;
        char *buf;
        static int used_event_hook;

        if (e == NULL || h == NULL)
                rl_initialize();

        rl_done = 0;

        (void)setjmp(topbuf);

        /* update prompt accordingly to what has been passed */
        if (!prompt)
                prompt = "";
        if (strcmp(rl_prompt, prompt) != 0) {
                free(rl_prompt);
                rl_prompt = strdup(prompt);
                if (rl_prompt == NULL)
                        return NULL;
        }

        if (rl_pre_input_hook)
                (*rl_pre_input_hook)(NULL, 0);

        if (rl_event_hook && !(e->el_flags&NO_TTY)) {
                el_set(e, EL_GETCFN, _rl_event_read_char);
                used_event_hook = 1;
        }

        if (!rl_event_hook && used_event_hook) {
                el_set(e, EL_GETCFN, EL_BUILTIN_GETCFN);
                used_event_hook = 0;
        }

        rl_already_prompted = 0;

        /* get one line from input stream */
        ret = el_gets(e, &count);

        if (ret && count > 0) {
                int lastidx;

                buf = strdup(ret);
                if (buf == NULL)
                        return NULL;
                lastidx = count - 1;
                if (buf[lastidx] == '\n')
                        buf[lastidx] = '\0';
        } else
                buf = NULL;

        history(h, &ev, H_GETSIZE);
        history_length = ev.num;

        return buf;
}

/*
 * history functions
 */

/*
 * is normally called before application starts to use
 * history expansion functions
 */
void
using_history(void)
{
        if (h == NULL || e == NULL)
                rl_initialize();
}


/*
 * substitute ``what'' with ``with'', returning resulting string; if
 * globally == 1, substitutes all occurrences of what, otherwise only the
 * first one
 */
static char *
_rl_compat_sub(const char *str, const char *what, const char *with,
    int globally)
{
        const   char    *s;
        char    *r, *result;
        size_t  len, with_len, what_len;

        len = strlen(str);
        with_len = strlen(with);
        what_len = strlen(what);

        /* calculate length we need for result */
        s = str;
        while (*s) {
                if (*s == *what && !strncmp(s, what, what_len)) {
                        len += with_len - what_len;
                        if (!globally)
                                break;
                        s += what_len;
                } else
                        s++;
        }
        r = result = malloc(len + 1);
        if (result == NULL)
                return NULL;
        s = str;
        while (*s) {
                if (*s == *what && !strncmp(s, what, what_len)) {
                        (void)strncpy(r, with, with_len);
                        r += with_len;
                        s += what_len;
                        if (!globally) {
                                (void)strcpy(r, s);
                                return(result);
                        }
                } else
                        *r++ = *s++;
        }
        *r = 0;
        return(result);
}

static  char    *last_search_pat;       /* last !?pat[?] search pattern */
static  char    *last_search_match;     /* last !?pat[?] that matched */

const char *
get_history_event(const char *cmd, int *cindex, int qchar)
{
        int idx, sign, sub, num, begin, ret;
        size_t len;
        char    *pat;
        const char *rptr;
        HistEvent ev;

        idx = *cindex;
        if (cmd[idx++] != history_expansion_char)
                return(NULL);

        /* find out which event to take */
        if (cmd[idx] == history_expansion_char || cmd[idx] == 0) {
                if (history(h, &ev, H_FIRST) != 0)
                        return(NULL);
                *cindex = cmd[idx]? (idx + 1):idx;
                return(ev.str);
        }
        sign = 0;
        if (cmd[idx] == '-') {
                sign = 1;
                idx++;
        }

        if ('0' <= cmd[idx] && cmd[idx] <= '9') {
                HIST_ENTRY *rl_he;

                num = 0;
                while (cmd[idx] && '0' <= cmd[idx] && cmd[idx] <= '9') {
                        num = num * 10 + cmd[idx] - '0';
                        idx++;
                }
                if (sign)
                        num = history_length - num + 1;

                if (!(rl_he = history_get(num)))
                        return(NULL);

                *cindex = idx;
                return(rl_he->line);
        }
        sub = 0;
        if (cmd[idx] == '?') {
                sub = 1;
                idx++;
        }
        begin = idx;
        while (cmd[idx]) {
                if (cmd[idx] == '\n')
                        break;
                if (sub && cmd[idx] == '?')
                        break;
                if (!sub && (cmd[idx] == ':' || cmd[idx] == ' '
                                    || cmd[idx] == '\t' || cmd[idx] == qchar))
                        break;
                idx++;
        }
        len = idx - begin;
        if (sub && cmd[idx] == '?')
                idx++;
        if (sub && len == 0 && last_search_pat && *last_search_pat)
                pat = last_search_pat;
        else if (len == 0)
                return(NULL);
        else {
                if ((pat = malloc(len + 1)) == NULL)
                        return NULL;
                (void)strncpy(pat, cmd + begin, len);
                pat[len] = '\0';
        }

        if (history(h, &ev, H_CURR) != 0) {
                if (pat != last_search_pat)
                        free(pat);
                return (NULL);
        }
        num = ev.num;

        if (sub) {
                if (pat != last_search_pat) {
                        if (last_search_pat)
                                free(last_search_pat);
                        last_search_pat = pat;
                }
                ret = history_search(pat, -1);
        } else
                ret = history_search_prefix(pat, -1);

        if (ret == -1) {
                /* restore to end of list on failed search */
                history(h, &ev, H_FIRST);
                (void)fprintf(rl_outstream, "%s: Event not found\n", pat);
                if (pat != last_search_pat)
                        free(pat);
                return(NULL);
        }

        if (sub && len) {
                if (last_search_match && last_search_match != pat)
                        free(last_search_match);
                last_search_match = pat;
        }

        if (pat != last_search_pat)
                free(pat);

        if (history(h, &ev, H_CURR) != 0)
                return(NULL);
        *cindex = idx;
        rptr = ev.str;

        /* roll back to original position */
        (void)history(h, &ev, H_SET, num);

        return rptr;
}

/*
 * the real function doing history expansion - takes as argument command
 * to do and data upon which the command should be executed
 * does expansion the way I've understood readline documentation
 *
 * returns 0 if data was not modified, 1 if it was and 2 if the string
 * should be only printed and not executed; in case of error,
 * returns -1 and *result points to NULL
 * it's callers responsibility to free() string returned in *result
 */
static int
_history_expand_command(const char *command, size_t offs, size_t cmdlen,
    char **result)
{
        char *tmp, *search = NULL, *aptr;
        const char *ptr, *cmd;
        static char *from = NULL, *to = NULL;
        int start, end, idx, has_mods = 0;
        int p_on = 0, g_on = 0;

        *result = NULL;
        aptr = NULL;
        ptr = NULL;

        /* First get event specifier */
        idx = 0;

        if (strchr(":^*$", command[offs + 1])) {
                char str[4];
                /*
                * "!:" is shorthand for "!!:".
                * "!^", "!*" and "!$" are shorthand for
                * "!!:^", "!!:*" and "!!:$" respectively.
                */
                str[0] = str[1] = '!';
                str[2] = '0';
                ptr = get_history_event(str, &idx, 0);
                idx = (command[offs + 1] == ':')? 1:0;
                has_mods = 1;
        } else {
                if (command[offs + 1] == '#') {
                        /* use command so far */
                        if ((aptr = malloc(offs + 1)) == NULL)
                                return -1;
                        (void)strncpy(aptr, command, offs);
                        aptr[offs] = '\0';
                        idx = 1;
                } else {
                        int     qchar;

                        qchar = (offs > 0 && command[offs - 1] == '"')? '"':0;
                        ptr = get_history_event(command + offs, &idx, qchar);
                }
                has_mods = command[offs + idx] == ':';
        }

        if (ptr == NULL && aptr == NULL)
                return(-1);

        if (!has_mods) {
                *result = strdup(aptr? aptr : ptr);
                if (aptr)
                        free(aptr);
                return(1);
        }

        cmd = command + offs + idx + 1;

        /* Now parse any word designators */

        if (*cmd == '%')        /* last word matched by ?pat? */
                tmp = strdup(last_search_match? last_search_match:"");
        else if (strchr("^*$-0123456789", *cmd)) {
                start = end = -1;
                if (*cmd == '^')
                        start = end = 1, cmd++;
                else if (*cmd == '$')
                        start = -1, cmd++;
                else if (*cmd == '*')
                        start = 1, cmd++;
               else if (*cmd == '-' || isdigit((unsigned char) *cmd)) {
                        start = 0;
                        while (*cmd && '0' <= *cmd && *cmd <= '9')
                                start = start * 10 + *cmd++ - '0';

                        if (*cmd == '-') {
                                if (isdigit((unsigned char) cmd[1])) {
                                        cmd++;
                                        end = 0;
                                        while (*cmd && '0' <= *cmd && *cmd <= '9')
                                                end = end * 10 + *cmd++ - '0';
                                } else if (cmd[1] == '$') {
                                        cmd += 2;
                                        end = -1;
                                } else {
                                        cmd++;
                                        end = -2;
                                }
                        } else if (*cmd == '*')
                                end = -1, cmd++;
                        else
                                end = start;
                }
                tmp = history_arg_extract(start, end, aptr? aptr:ptr);
                if (tmp == NULL) {
                        (void)fprintf(rl_outstream, "%s: Bad word specifier",
                            command + offs + idx);
                        if (aptr)
                                free(aptr);
                        return(-1);
                }
        } else
                tmp = strdup(aptr? aptr:ptr);

        if (aptr)
                free(aptr);

        if (*cmd == 0 || (cmd - (command + offs) >= cmdlen)) {
                *result = tmp;
                return(1);
        }

        for (; *cmd; cmd++) {
                if (*cmd == ':')
                        continue;
                else if (*cmd == 'h') {         /* remove trailing path */
                        if ((aptr = strrchr(tmp, '/')) != NULL)
                                *aptr = 0;
                } else if (*cmd == 't') {       /* remove leading path */
                        if ((aptr = strrchr(tmp, '/')) != NULL) {
                                aptr = strdup(aptr + 1);
                                free(tmp);
                                tmp = aptr;
                        }
                } else if (*cmd == 'r') {       /* remove trailing suffix */
                        if ((aptr = strrchr(tmp, '.')) != NULL)
                                *aptr = 0;
                } else if (*cmd == 'e') {       /* remove all but suffix */
                        if ((aptr = strrchr(tmp, '.')) != NULL) {
                                aptr = strdup(aptr);
                                free(tmp);
                                tmp = aptr;
                        }
                } else if (*cmd == 'p')         /* print only */
                        p_on = 1;
                else if (*cmd == 'g')
                        g_on = 2;
                else if (*cmd == 's' || *cmd == '&') {
                        char *what, *with, delim;
                        size_t len, from_len;
                        size_t size;

                        if (*cmd == '&' && (from == NULL || to == NULL))
                                continue;
                        else if (*cmd == 's') {
                                delim = *(++cmd), cmd++;
                                size = 16;
                                what = realloc(from, size);
                                if (what == NULL) {
                                        free(from);
                                        free(tmp);
                                        return 0;
                                }
                                len = 0;
                                for (; *cmd && *cmd != delim; cmd++) {
                                        if (*cmd == '\\' && cmd[1] == delim)
                                                cmd++;
                                        if (len >= size) {
                                                char *nwhat;
                                                nwhat = realloc(what,
                                                                (size <<= 1));
                                                if (nwhat == NULL) {
                                                        free(what);
                                                        free(tmp);
                                                        return 0;
                                                }
                                                what = nwhat;
                                        }
                                        what[len++] = *cmd;
                                }
                                what[len] = '\0';
                                from = what;
                                if (*what == '\0') {
                                        free(what);
                                        if (search) {
                                                from = strdup(search);
                                                if (from == NULL) {
                                                        free(tmp);
                                                        return 0;
                                                }
                                        } else {
                                                from = NULL;
                                                free(tmp);
                                                return (-1);
                                        }
                                }
                                cmd++;  /* shift after delim */
                                if (!*cmd)
                                        continue;

                                size = 16;
                                with = realloc(to, size);
                                if (with == NULL) {
                                        free(to);
                                        free(tmp);
                                        return -1;
                                }
                                len = 0;
                                from_len = strlen(from);
                                for (; *cmd && *cmd != delim; cmd++) {
                                        if (len + from_len + 1 >= size) {
                                                char *nwith;
                                                size += from_len + 1;
                                                nwith = realloc(with, size);
                                                if (nwith == NULL) {
                                                        free(with);
                                                        free(tmp);
                                                        return -1;
                                                }
                                                with = nwith;
                                        }
                                        if (*cmd == '&') {
                                                /* safe */
                                                (void)strcpy(&with[len], from);
                                                len += from_len;
                                                continue;
                                        }
                                        if (*cmd == '\\'
                                            && (*(cmd + 1) == delim
                                                || *(cmd + 1) == '&'))
                                                cmd++;
                                        with[len++] = *cmd;
                                }
                                with[len] = '\0';
                                to = with;
                        }

                        aptr = _rl_compat_sub(tmp, from, to, g_on);
                        if (aptr) {
                                free(tmp);
                                tmp = aptr;
                        }
                        g_on = 0;
                }
        }
        *result = tmp;
        return (p_on? 2:1);
}


/*
 * csh-style history expansion
 */
int
history_expand(char *str, char **output)
{
        int ret = 0;
        size_t idx, i, size;
        char *tmp, *result;

        if (h == NULL || e == NULL)
                rl_initialize();

        if (history_expansion_char == 0) {
                *output = strdup(str);
                return(0);
        }

        *output = NULL;
        if (str[0] == history_subst_char) {
                /* ^foo^foo2^ is equivalent to !!:s^foo^foo2^ */
                *output = malloc(strlen(str) + 4 + 1);
                if (*output == NULL)
                        return 0;
                (*output)[0] = (*output)[1] = history_expansion_char;
                (*output)[2] = ':';
                (*output)[3] = 's';
                (void)strcpy((*output) + 4, str);
                str = *output;
        } else {
                *output = strdup(str);
                if (*output == NULL)
                        return 0;
        }

#define ADD_STRING(what, len, fr)                                       \
        {                                                               \
                if (idx + len + 1 > size) {                             \
                        char *nresult = realloc(result, (size += len + 1));\
                        if (nresult == NULL) {                          \
                                free(*output);                          \
                                if (/*CONSTCOND*/fr)                    \
                                        free(tmp);                      \
                                return 0;                               \
                        }                                               \
                        result = nresult;                               \
                }                                                       \
                (void)strncpy(&result[idx], what, len);                 \
                idx += len;                                             \
                result[idx] = '\0';                                     \
        }

        result = NULL;
        size = idx = 0;
        tmp = NULL;
        for (i = 0; str[i];) {
                int qchar, loop_again;
                size_t len, start, j;

                qchar = 0;
                loop_again = 1;
                start = j = i;
loop:
                for (; str[j]; j++) {
                        if (str[j] == '\\' &&
                            str[j + 1] == history_expansion_char) {
                                (void)strcpy(&str[j], &str[j + 1]);
                                continue;
                        }
                        if (!loop_again) {
                                if (isspace((unsigned char) str[j])
                                    || str[j] == qchar)
                                        break;
                        }
                        if (str[j] == history_expansion_char
                            && !strchr(history_no_expand_chars, str[j + 1])
                            && (!history_inhibit_expansion_function ||
                            (*history_inhibit_expansion_function)(str,
                            (int)j) == 0))
                                break;
                }

                if (str[j] && loop_again) {
                        i = j;
                        qchar = (j > 0 && str[j - 1] == '"' )? '"':0;
                        j++;
                        if (str[j] == history_expansion_char)
                                j++;
                        loop_again = 0;
                        goto loop;
                }
                len = i - start;
                ADD_STRING(&str[start], len, 0);

                if (str[i] == '\0' || str[i] != history_expansion_char) {
                        len = j - i;
                        ADD_STRING(&str[i], len, 0);
                        if (start == 0)
                                ret = 0;
                        else
                                ret = 1;
                        break;
                }
                ret = _history_expand_command (str, i, (j - i), &tmp);
                if (ret > 0 && tmp) {
                        len = strlen(tmp);
                        ADD_STRING(tmp, len, 1);
                }
                if (tmp) {
                        free(tmp);
                        tmp = NULL;
                }
                i = j;
        }

        /* ret is 2 for "print only" option */
        if (ret == 2) {
                add_history(result);
#ifdef GDB_411_HACK
                /* gdb 4.11 has been shipped with readline, where */
                /* history_expand() returned -1 when the line     */
                /* should not be executed; in readline 2.1+       */
                /* it should return 2 in such a case              */
                ret = -1;
#endif
        }
        free(*output);
        *output = result;

        return (ret);
}

/*
* Return a string consisting of arguments of "str" from "start" to "end".
*/
char *
history_arg_extract(int start, int end, const char *str)
{
        size_t  i, len, max;
        char    **arr, *result;

        arr = history_tokenize(str);
        if (!arr)
                return(NULL);
        if (arr && *arr == NULL) {
                free(arr);
                return(NULL);
        }

        for (max = 0; arr[max]; max++)
                continue;
        max--;

        if (start == '$')
                start = max;
        if (end == '$')
                end = max;
        if (end < 0)
                end = max + end + 1;
        if (start < 0)
                start = end;

        if (start < 0 || end < 0 || start > max || end > max || start > end)
                return(NULL);

        for (i = start, len = 0; i <= end; i++)
                len += strlen(arr[i]) + 1;
        len++;
        result = malloc(len);
        if (result == NULL)
                return NULL;

        for (i = start, len = 0; i <= end; i++) {
                (void)strcpy(result + len, arr[i]);
                len += strlen(arr[i]);
                if (i < end)
                        result[len++] = ' ';
        }
        result[len] = 0;

        for (i = 0; arr[i]; i++)
                free(arr[i]);
        free(arr);

        return(result);
}

/*
 * Parse the string into individual tokens,
 * similar to how shell would do it.
 */
char **
history_tokenize(const char *str)
{
        int size = 1, idx = 0, i, start;
        size_t len;
        char **result = NULL, *temp, delim = '\0';

        for (i = 0; str[i];) {
                while (isspace((unsigned char) str[i]))
                        i++;
                start = i;
                for (; str[i];) {
                        if (str[i] == '\\') {
                                if (str[i+1] != '\0')
                                        i++;
                        } else if (str[i] == delim)
                                delim = '\0';
                        else if (!delim &&
                                    (isspace((unsigned char) str[i]) ||
                                strchr("()<>;&|$", str[i])))
                                break;
                        else if (!delim && strchr("'`\"", str[i]))
                                delim = str[i];
                        if (str[i])
                                i++;
                }

                if (idx + 2 >= size) {
                        char **nresult;
                        size <<= 1;
                        nresult = realloc(result, size * sizeof(char *));
                        if (nresult == NULL) {
                                free(result);
                                return NULL;
                        }
                        result = nresult;
                }
                len = i - start;
                temp = malloc(len + 1);
                if (temp == NULL) {
                        for (i = 0; i < idx; i++)
                                free(result[i]);
                        free(result);
                        return NULL;
                }
                (void)strncpy(temp, &str[start], len);
                temp[len] = '\0';
                result[idx++] = temp;
                result[idx] = NULL;
                if (str[i])
                        i++;
        }
        return (result);
}


/*
 * limit size of history record to ``max'' events
 */
void
stifle_history(int max)
{
        HistEvent ev;

        if (h == NULL || e == NULL)
                rl_initialize();

        if (history(h, &ev, H_SETSIZE, max) == 0)
                max_input_history = max;
}


/*
 * "unlimit" size of history - set the limit to maximum allowed int value
 */
int
unstifle_history(void)
{
        HistEvent ev;
        int omax;

        history(h, &ev, H_SETSIZE, INT_MAX);
        omax = max_input_history;
        max_input_history = INT_MAX;
        return (omax);          /* some value _must_ be returned */
}


int
history_is_stifled(void)
{

        /* cannot return true answer */
        return (max_input_history != INT_MAX);
}


/*
 * read history from a file given
 */
int
read_history(const char *filename)
{
        HistEvent ev;

        if (h == NULL || e == NULL)
                rl_initialize();
        return (history(h, &ev, H_LOAD, filename) == -1);
}


/*
 * write history to a file given
 */
int
write_history(const char *filename)
{
        HistEvent ev;

        if (h == NULL || e == NULL)
                rl_initialize();
        return (history(h, &ev, H_SAVE, filename) == -1);
}


/*
 * returns history ``num''th event
 *
 * returned pointer points to static variable
 */
HIST_ENTRY *
history_get(int num)
{
        static HIST_ENTRY she;
        HistEvent ev;
        int curr_num;

        if (h == NULL || e == NULL)
                rl_initialize();

        /* save current position */
        if (history(h, &ev, H_CURR) != 0)
                return (NULL);
        curr_num = ev.num;

        /* start from most recent */
        if (history(h, &ev, H_FIRST) != 0)
                return (NULL);  /* error */

        /* look backwards for event matching specified offset */
        if (history(h, &ev, H_NEXT_EVENT, num + 1))
                return (NULL);

        she.line = ev.str;
        she.data = NULL;

        /* restore pointer to where it was */
        (void)history(h, &ev, H_SET, curr_num);

        return (&she);
}


/*
 * add the line to history table
 */
int
add_history(const char *line)
{
        HistEvent ev;

        if (h == NULL || e == NULL)
                rl_initialize();

        (void)history(h, &ev, H_ENTER, line);
        if (history(h, &ev, H_GETSIZE) == 0)
                history_length = ev.num;

        return (!(history_length > 0)); /* return 0 if all is okay */
}


/*
 * remove the specified entry from the history list and return it.
 */
HIST_ENTRY *
remove_history(int num)
{
        HIST_ENTRY *she;
        HistEvent ev;

        if (h == NULL || e == NULL)
                rl_initialize();

        if (history(h, &ev, H_DEL, num) != 0)
                return NULL;

        if ((she = malloc(sizeof(*she))) == NULL)
                return NULL;

        she->line = ev.str;
        she->data = NULL;

        return she;
}


/*
 * clear the history list - delete all entries
 */
void
clear_history(void)
{
        HistEvent ev;

        history(h, &ev, H_CLEAR);
}


/*
 * returns offset of the current history event
 */
int
where_history(void)
{
        HistEvent ev;
        int curr_num, off;

        if (history(h, &ev, H_CURR) != 0)
                return (0);
        curr_num = ev.num;

        history(h, &ev, H_FIRST);
        off = 1;
        while (ev.num != curr_num && history(h, &ev, H_NEXT) == 0)
                off++;

        return (off);
}


/*
 * returns current history event or NULL if there is no such event
 */
HIST_ENTRY *
current_history(void)
{

        return (_move_history(H_CURR));
}


/*
 * returns total number of bytes history events' data are using
 */
int
history_total_bytes(void)
{
        HistEvent ev;
        int curr_num, size;

        if (history(h, &ev, H_CURR) != 0)
                return (-1);
        curr_num = ev.num;

        history(h, &ev, H_FIRST);
        size = 0;
        do
                size += strlen(ev.str);
        while (history(h, &ev, H_NEXT) == 0);

        /* get to the same position as before */
        history(h, &ev, H_PREV_EVENT, curr_num);

        return (size);
}


/*
 * sets the position in the history list to ``pos''
 */
int
history_set_pos(int pos)
{
        HistEvent ev;
        int curr_num;

        if (pos > history_length || pos < 0)
                return (-1);

        history(h, &ev, H_CURR);
        curr_num = ev.num;

        if (history(h, &ev, H_SET, pos)) {
                history(h, &ev, H_SET, curr_num);
                return(-1);
        }
        return (0);
}


/*
 * returns previous event in history and shifts pointer accordingly
 */
HIST_ENTRY *
previous_history(void)
{

        return (_move_history(H_PREV));
}


/*
 * returns next event in history and shifts pointer accordingly
 */
HIST_ENTRY *
next_history(void)
{

        return (_move_history(H_NEXT));
}


/*
 * searches for first history event containing the str
 */
int
history_search(const char *str, int direction)
{
        HistEvent ev;
        const char *strp;
        int curr_num;

        if (history(h, &ev, H_CURR) != 0)
                return (-1);
        curr_num = ev.num;

        for (;;) {
                if ((strp = strstr(ev.str, str)) != NULL)
                        return (int) (strp - ev.str);
                if (history(h, &ev, direction < 0 ? H_NEXT:H_PREV) != 0)
                        break;
        }
        history(h, &ev, H_SET, curr_num);
        return (-1);
}


/*
 * searches for first history event beginning with str
 */
int
history_search_prefix(const char *str, int direction)
{
        HistEvent ev;

        return (history(h, &ev, direction < 0? H_PREV_STR:H_NEXT_STR, str));
}


/*
 * search for event in history containing str, starting at offset
 * abs(pos); continue backward, if pos<0, forward otherwise
 */
/* ARGSUSED */
int
history_search_pos(const char *str,
                   int direction __attribute__((__unused__)), int pos)
{
        HistEvent ev;
        int curr_num, off;

        off = (pos > 0) ? pos : -pos;
        pos = (pos > 0) ? 1 : -1;

        if (history(h, &ev, H_CURR) != 0)
                return (-1);
        curr_num = ev.num;

        if (history_set_pos(off) != 0 || history(h, &ev, H_CURR) != 0)
                return (-1);


        for (;;) {
                if (strstr(ev.str, str))
                        return (off);
                if (history(h, &ev, (pos < 0) ? H_PREV : H_NEXT) != 0)
                        break;
        }

        /* set "current" pointer back to previous state */
        history(h, &ev, (pos < 0) ? H_NEXT_EVENT : H_PREV_EVENT, curr_num);

        return (-1);
}


/********************************/
/* completion functions */

char *
tilde_expand(char *name)
{
        return fn_tilde_expand(name);
}

char *
filename_completion_function(const char *name, int state)
{
        return fn_filename_completion_function(name, state);
}

/*
 * a completion generator for usernames; returns _first_ username
 * which starts with supplied text
 * text contains a partial username preceded by random character
 * (usually '~'); state is ignored
 * it's callers responsibility to free returned value
 */
char *
username_completion_function(const char *text, int state)
{
        /*
                For when getpwent_r is supported:
        struct passwd *pwd, pwres;
        char pwbuf[1024];
        */
        struct passwd *pwd;
        /* remove the above when getpwend_r is supported */

        if (text[0] == '\0')
                return (NULL);

        if (*text == '~')
                text++;

        if (state == 0)
                setpwent();

        /*
                For when getpwent_r is supported:
        while (getpwent_r(&pwres, pwbuf, sizeof(pwbuf), &pwd) == 0
            && pwd != NULL && text[0] == pwd->pw_name[0]
            && strcmp(text, pwd->pw_name) == 0);
        */
        for (;;) {
                pwd = getpwent();
                if (pwd != NULL && text[0] == pwd->pw_name[0] && strcmp(text, pwd->pw_name) == 0)
                        break;
                
        }
        /* remove the above when getpwend_r is supported */

        if (pwd == NULL) {
                endpwent();
                return (NULL);
        }
        return (strdup(pwd->pw_name));
}


/*
 * el-compatible wrapper to send TSTP on ^Z
 */
/* ARGSUSED */
static unsigned char
_el_rl_tstp(EditLine *el __attribute__((__unused__)), int ch __attribute__((__unused__)))
{
        (void)kill(0, SIGTSTP);
        return CC_NORM;
}

/*
 * Display list of strings in columnar format on readline's output stream.
 * 'matches' is list of strings, 'len' is number of strings in 'matches',
 * 'max' is maximum length of string in 'matches'.
 */
void
rl_display_match_list(char **matches, int len, int max)
{

        fn_display_match_list(e, matches, len, max);
}

static const char *
/*ARGSUSED*/
_rl_completion_append_character_function(const char *dummy
    __attribute__((__unused__)))
{
        static char buf[2];
        buf[1] = rl_completion_append_character;
        return buf;
}


/*
 * complete word at current point
 */
/* ARGSUSED */
int
rl_complete(int ignore __attribute__((__unused__)), int invoking_key)
{
        char *breakchars = NULL;

        if (h == NULL || e == NULL)
                rl_initialize();

        if (rl_inhibit_completion) {
                char arr[2];
                arr[0] = (char)invoking_key;
                arr[1] = '\0';
                el_insertstr(e, arr);
                return (CC_REFRESH);
        }

        if (rl_completion_word_break_hook != NULL)
                breakchars = rl_completion_word_break_hook();
        if (breakchars == NULL)
                breakchars = rl_basic_word_break_characters;

        /* Just look at how many global variables modify this operation! */
        return fn_complete(e,
            (CPFunction *)rl_completion_entry_function,
            rl_attempted_completion_function,
            breakchars, rl_special_prefixes,
            _rl_completion_append_character_function, rl_completion_query_items,
            &rl_completion_type, &rl_attempted_completion_over,
            &rl_point, &rl_end);
}


/* ARGSUSED */
static unsigned char
_el_rl_complete(EditLine *el __attribute__((__unused__)), int ch)
{
        return (unsigned char)rl_complete(0, ch);
}

/*
 * misc other functions
 */

/*
 * bind key c to readline-type function func
 */
int
rl_bind_key(int c, int func(int, int))
{
        int retval = -1;

        if (h == NULL || e == NULL)
                rl_initialize();

        if (func == rl_insert) {
                /* XXX notice there is no range checking of ``c'' */
                e->el_map.key[c] = ED_INSERT;
                retval = 0;
        }
        return (retval);
}


/*
 * read one key from input - handles chars pushed back
 * to input stream also
 */
int
rl_read_key(void)
{
        char fooarr[2 * sizeof(int)];

        if (e == NULL || h == NULL)
                rl_initialize();

        return (el_getc(e, fooarr));
}


/*
 * reset the terminal
 */
/* ARGSUSED */
void
rl_reset_terminal(const char *p __attribute__((__unused__)))
{

        if (h == NULL || e == NULL)
                rl_initialize();
        el_reset(e);
}


/*
 * insert character ``c'' back into input stream, ``count'' times
 */
int
rl_insert(int count, int c)
{
        char arr[2];

        if (h == NULL || e == NULL)
                rl_initialize();

        /* XXX - int -> char conversion can lose on multichars */
        arr[0] = c;
        arr[1] = '\0';

        for (; count > 0; count--)
                el_push(e, arr);

        return (0);
}

/*ARGSUSED*/
int
rl_newline(int count, int c)
{
        /*
         * Readline-4.0 appears to ignore the args.
         */
        return rl_insert(1, '\n');
}

/*ARGSUSED*/
static unsigned char
rl_bind_wrapper(EditLine *el, unsigned char c)
{
        if (map[c] == NULL)
            return CC_ERROR;

        _rl_update_pos();

        (*map[c])(NULL, c);

        /* If rl_done was set by the above call, deal with it here */
        if (rl_done)
                return CC_EOF;

        return CC_NORM;
}

int
rl_add_defun(const char *name, Function *fun, int c)
{
        char dest[8];
        if (c >= sizeof(map) / sizeof(map[0]) || c < 0)
                return -1;
        map[(unsigned char)c] = fun;
        el_set(e, EL_ADDFN, name, name, rl_bind_wrapper);
        vis(dest, c, VIS_WHITE|VIS_NOSLASH, 0);
        el_set(e, EL_BIND, dest, name);
        return 0;
}

void
rl_callback_read_char(void)
{
        int count = 0, done = 0;
        const char *buf = el_gets(e, &count);
        char *wbuf;

        if (buf == NULL || count-- <= 0)
                return;
        if (count == 0 && buf[0] == e->el_tty.t_c[TS_IO][C_EOF])
                done = 1;
        if (buf[count] == '\n' || buf[count] == '\r')
                done = 2;

        if (done && rl_linefunc != NULL) {
                el_set(e, EL_UNBUFFERED, 0);
                if (done == 2) {
                    if ((wbuf = strdup(buf)) != NULL)
                        wbuf[count] = '\0';
                } else
                        wbuf = NULL;
                (*(void (*)(const char *))rl_linefunc)(wbuf);
                el_set(e, EL_UNBUFFERED, 1);
        }
}

void 
rl_callback_handler_install(const char *prompt, VCPFunction *linefunc)
{
        if (e == NULL) {
                rl_initialize();
        }
        if (rl_prompt)
                free(rl_prompt);
        rl_prompt = prompt ? strdup(strchr(prompt, *prompt)) : NULL;
        rl_linefunc = linefunc;
        el_set(e, EL_UNBUFFERED, 1);
}   

void 
rl_callback_handler_remove(void)
{
        el_set(e, EL_UNBUFFERED, 0);
        rl_linefunc = NULL;
}

void
rl_redisplay(void)
{
        char a[2];
        a[0] = e->el_tty.t_c[TS_IO][C_REPRINT];
        a[1] = '\0';
        el_push(e, a);
}

int
rl_get_previous_history(int count, int key)
{
        char a[2];
        a[0] = key;
        a[1] = '\0';
        while (count--)
                el_push(e, a);
        return 0;
}

void
/*ARGSUSED*/
rl_prep_terminal(int meta_flag)
{
        el_set(e, EL_PREP_TERM, 1);
}

void
rl_deprep_terminal(void)
{
        el_set(e, EL_PREP_TERM, 0);
}

int
rl_read_init_file(const char *s)
{
        return(el_source(e, s));
}

int
rl_parse_and_bind(const char *line)
{
        const char **argv;
        int argc;
        Tokenizer *tok;

        tok = tok_init(NULL);
        tok_str(tok, line, &argc, &argv);
        argc = el_parse(e, argc, argv);
        tok_end(tok);
        return (argc ? 1 : 0);
}

int
rl_variable_bind(const char *var, const char *value)
{
        /*
         * The proper return value is undocument, but this is what the
         * readline source seems to do.
         */
        return ((el_set(e, EL_BIND, "", var, value) == -1) ? 1 : 0);
}

void
rl_stuff_char(int c)
{
        char buf[2];

        buf[0] = c;
        buf[1] = '\0';
        el_insertstr(e, buf);
}

static int
_rl_event_read_char(EditLine *el, char *cp)
{
        int     n, num_read = 0;

        *cp = 0;
        while (rl_event_hook) {

                (*rl_event_hook)();

#if defined(FIONREAD)
                if (ioctl(el->el_infd, FIONREAD, &n) < 0)
                        return(-1);
                if (n)
                        num_read = read(el->el_infd, cp, 1);
                else
                        num_read = 0;
#elif defined(F_SETFL) && defined(O_NDELAY)
                if ((n = fcntl(el->el_infd, F_GETFL, 0)) < 0)
                        return(-1);
                if (fcntl(el->el_infd, F_SETFL, n|O_NDELAY) < 0)
                        return(-1);
                num_read = read(el->el_infd, cp, 1);
                if (fcntl(el->el_infd, F_SETFL, n))
                        return(-1);
#else
                /* not non-blocking, but what you gonna do? */
                num_read = read(el->el_infd, cp, 1);
                return(-1);
#endif

                if (num_read < 0 && errno == EAGAIN)
                        continue;
                if (num_read == 0)
                        continue;
                break;
        }
        if (!rl_event_hook)
                el_set(el, EL_GETCFN, EL_BUILTIN_GETCFN);
        return(num_read);
}

static void
_rl_update_pos(void)
{
        const LineInfo *li = el_line(e);

        rl_point = li->cursor - li->buffer;
        rl_end = li->lastchar - li->buffer;
}

void
rl_get_screen_size(int *rows, int *cols)
{
        if (rows)
                el_get(e, EL_GETTC, "li", rows);
        if (cols)
                el_get(e, EL_GETTC, "co", cols);
}

void
rl_set_screen_size(int rows, int cols)
{
        char buf[64];
        (void)snprintf(buf, sizeof(buf), "%d", rows);
        el_set(e, EL_SETTC, "li", buf);
        (void)snprintf(buf, sizeof(buf), "%d", cols);
        el_set(e, EL_SETTC, "co", buf);
}

char **
rl_completion_matches(const char *str, rl_compentry_func_t *fun)
{
        size_t len, max, i, j, min;
        char **list, *match, *a, *b;

        len = 1;
        max = 10;
        if ((list = malloc(max * sizeof(*list))) == NULL)
                return NULL;

        while ((match = (*fun)(str, (int)(len - 1))) != NULL) {
                if (len == max) {
                        char **nl;
                        max += 10;
                        if ((nl = realloc(list, max * sizeof(*nl))) == NULL)
                                goto out;
                        list = nl;
                }
                list[len++] = match;
        }
        if (len == 1)
                goto out;
        list[len] = NULL;
        if (len == 2) {
                if ((list[0] = strdup(list[1])) == NULL)
                        goto out;
                return list;
        }
        qsort(&list[1], len - 1, sizeof(*list),
            (int (*)(const void *, const void *)) strcmp);
        min = SIZE_T_MAX;
        for (i = 1, a = list[i]; i < len - 1; i++, a = b) {
                b = list[i + 1];
                for (j = 0; a[j] && a[j] == b[j]; j++)
                        continue;
                if (min > j)
                        min = j;
        }
        if (min == 0 && *str) {
                if ((list[0] = strdup(str)) == NULL)
                        goto out;
        } else {
                if ((list[0] = malloc(min + 1)) == NULL)
                        goto out;
                (void)memcpy(list[0], list[1], min);
                list[0][min] = '\0';
        }
        return list;

out:
        free(list);
        return NULL;
}

char *
rl_filename_completion_function (const char *text, int state)
{
        return fn_filename_completion_function(text, state);
}

void
rl_forced_update_display(void)
{
        el_set(e, EL_REFRESH);
}

int
_rl_abort_internal(void)
{
        el_beep(e);
        longjmp(topbuf, 1);
        /*NOTREACHED*/
}

int
_rl_qsort_string_compare(char **s1, char **s2)
{
        return strcoll(*s1, *s2);
}

int
/*ARGSUSED*/
rl_kill_text(int from, int to)
{
        return 0;
}

Keymap
rl_make_bare_keymap(void)
{
        return NULL;
}

Keymap
rl_get_keymap(void)
{
        return NULL;
}

void
/*ARGSUSED*/
rl_set_keymap(Keymap k)
{
}

int
/*ARGSUSED*/
rl_generic_bind(int type, const char * keyseq, const char * data, Keymap k)
{
        return 0;
}

int
/*ARGSUSED*/
rl_bind_key_in_map(int key, Function *fun, Keymap k)
{
        return 0;
}