x

[heimdal.git] / lib / roken / getcap.c

/*      $NetBSD: getcap.c,v 1.29 1999/03/29 09:27:29 abs Exp $  */

/*-
 * Copyright (c) 1992, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Casey Leedom of Lawrence Livermore National Laboratory.
 *
 * 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.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "roken.h"
RCSID("$Id$");

#include <sys/types.h>
#include <ctype.h>
#if defined(HAVE_DB_185_H)
#include <db_185.h>
#elif defined(HAVE_DB_H)
#include <db.h>
#endif
#include <errno.h>      
#include <fcntl.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#define BFRAG           1024
#if 0
#define BSIZE           1024
#endif
#define ESC             ('[' & 037)     /* ASCII ESC */
#define MAX_RECURSION   32              /* maximum getent recursion */
#define SFRAG           100             /* cgetstr mallocs in SFRAG chunks */

#define RECOK   (char)0
#define TCERR   (char)1
#define SHADOW  (char)2

static size_t    topreclen;     /* toprec length */
static char     *toprec;        /* Additional record specified by cgetset() */
static int       gottoprec;     /* Flag indicating retrieval of toprecord */

#if 0 /*
       * Don't use db support unless it's build into libc but we don't
       * check for that now, so just disable the code.
       */
#if defined(HAVE_DBOPEN) && defined(HAVE_DB_H)
#define USE_DB
#endif
#endif

#ifdef USE_DB
static int      cdbget (DB *, char **, const char *);
#endif
static int      getent (char **, size_t *, char **, int, const char *, int, char *);
static int      nfcmp (char *, char *);


int ROKEN_LIB_FUNCTION cgetset(const char *ent);
char *ROKEN_LIB_FUNCTION cgetcap(char *buf, const char *cap, int type);
int ROKEN_LIB_FUNCTION cgetent(char **buf, char **db_array, const char *name);
int ROKEN_LIB_FUNCTION cgetmatch(const char *buf, const char *name);
int ROKEN_LIB_FUNCTION cgetclose(void);
#if 0
int cgetfirst(char **buf, char **db_array);
int cgetnext(char **bp, char **db_array);
#endif
int ROKEN_LIB_FUNCTION cgetstr(char *buf, const char *cap, char **str);
int ROKEN_LIB_FUNCTION cgetustr(char *buf, const char *cap, char **str);
int ROKEN_LIB_FUNCTION cgetnum(char *buf, const char *cap, long *num);
/*
 * Cgetset() allows the addition of a user specified buffer to be added
 * to the database array, in effect "pushing" the buffer on top of the
 * virtual database. 0 is returned on success, -1 on failure.
 */
int ROKEN_LIB_FUNCTION
cgetset(const char *ent)
{
    const char *source, *check;
    char *dest;

    if (ent == NULL) {
        if (toprec)
            free(toprec);
        toprec = NULL;
        topreclen = 0;
        return (0);
    }
    topreclen = strlen(ent);
    if ((toprec = malloc (topreclen + 1)) == NULL) {
        errno = ENOMEM;
        return (-1);
    }
    gottoprec = 0;

    source=ent;
    dest=toprec;
    while (*source) { /* Strip whitespace */
        *dest++ = *source++; /* Do not check first field */
        while (*source == ':') {
            check=source+1;
            while (*check && (isspace((unsigned char)*check) ||
                              (*check=='\\' && isspace((unsigned char)check[1]))))
                ++check;
            if( *check == ':' )
                source=check;
            else
                break;

        }
    }
    *dest=0;

    return (0);
}

/*
 * Cgetcap searches the capability record buf for the capability cap with
 * type `type'.  A pointer to the value of cap is returned on success, NULL
 * if the requested capability couldn't be found.
 *
 * Specifying a type of ':' means that nothing should follow cap (:cap:).
 * In this case a pointer to the terminating ':' or NUL will be returned if
 * cap is found.
 *
 * If (cap, '@') or (cap, terminator, '@') is found before (cap, terminator)
 * return NULL.
 */
char * ROKEN_LIB_FUNCTION
cgetcap(char *buf, const char *cap, int type)
{
    char *bp;
    const char *cp;

    bp = buf;
    for (;;) {
        /*
         * Skip past the current capability field - it's either the
         * name field if this is the first time through the loop, or
         * the remainder of a field whose name failed to match cap.
         */
        for (;;)
            if (*bp == '\0')
                return (NULL);
            else
                if (*bp++ == ':')
                    break;

        /*
         * Try to match (cap, type) in buf.
         */
        for (cp = cap; *cp == *bp && *bp != '\0'; cp++, bp++)
            continue;
        if (*cp != '\0')
            continue;
        if (*bp == '@')
            return (NULL);
        if (type == ':') {
            if (*bp != '\0' && *bp != ':')
                continue;
            return(bp);
        }
        if (*bp != type)
            continue;
        bp++;
        return (*bp == '@' ? NULL : bp);
    }
    /* NOTREACHED */
}

/*
 * Cgetent extracts the capability record name from the NULL terminated file
 * array db_array and returns a pointer to a malloc'd copy of it in buf.
 * Buf must be retained through all subsequent calls to cgetcap, cgetnum,
 * cgetflag, and cgetstr, but may then be free'd.  0 is returned on success,
 * -1 if the requested record couldn't be found, -2 if a system error was
 * encountered (couldn't open/read a file, etc.), and -3 if a potential
 * reference loop is detected.
 */
int ROKEN_LIB_FUNCTION
cgetent(char **buf, char **db_array, const char *name)
{
    size_t dummy;

    return (getent(buf, &dummy, db_array, -1, name, 0, NULL));
}

/*
 * Getent implements the functions of cgetent.  If fd is non-negative,
 * *db_array has already been opened and fd is the open file descriptor.  We
 * do this to save time and avoid using up file descriptors for tc=
 * recursions.
 *
 * Getent returns the same success/failure codes as cgetent.  On success, a
 * pointer to a malloc'ed capability record with all tc= capabilities fully
 * expanded and its length (not including trailing ASCII NUL) are left in
 * *cap and *len.
 *
 * Basic algorithm:
 *      + Allocate memory incrementally as needed in chunks of size BFRAG
 *        for capability buffer.
 *      + Recurse for each tc=name and interpolate result.  Stop when all
 *        names interpolated, a name can't be found, or depth exceeds
 *        MAX_RECURSION.
 */
static int
getent(char **cap, size_t *len, char **db_array, int fd, 
       const char *name, int depth, char *nfield)
{
    char *r_end, *rp = NULL, **db_p;    /* pacify gcc */
    int myfd = 0, eof, foundit;
    char *record;
    int tc_not_resolved;
        
    /*
     * Return with ``loop detected'' error if we've recursed more than
     * MAX_RECURSION times.
     */
    if (depth > MAX_RECURSION)
        return (-3);

    /*
     * Check if we have a top record from cgetset().
     */
    if (depth == 0 && toprec != NULL && cgetmatch(toprec, name) == 0) {
        size_t len = topreclen + BFRAG;
        if ((record = malloc (len)) == NULL) {
            errno = ENOMEM;
            return (-2);
        }
        (void)strlcpy(record, toprec, len);
        db_p = db_array;
        rp = record + topreclen + 1;
        r_end = rp + BFRAG;
        goto tc_exp;
    }
    /*
     * Allocate first chunk of memory.
     */
    if ((record = malloc(BFRAG)) == NULL) {
        errno = ENOMEM;
        return (-2);
    }
    r_end = record + BFRAG;
    foundit = 0;
    /*
     * Loop through database array until finding the record.
     */

    for (db_p = db_array; *db_p != NULL; db_p++) {
        eof = 0;

        /*
         * Open database if not already open.
         */

        if (fd >= 0) {
            (void)lseek(fd, (off_t)0, SEEK_SET);
        } else {
#ifdef USE_DB
            char pbuf[_POSIX_PATH_MAX];
            char *cbuf;
            size_t clen;
            int retval;
            DB *capdbp;

            (void)snprintf(pbuf, sizeof(pbuf), "%s.db", *db_p);
            if ((capdbp = dbopen(pbuf, O_RDONLY, 0, DB_HASH, 0))
                != NULL) {
                free(record);
                retval = cdbget(capdbp, &record, name);
                if (retval < 0) {
                    /* no record available */
                    (void)capdbp->close(capdbp);
                    return (retval);
                }
                                /* save the data; close frees it */
                clen = strlen(record);
                cbuf = malloc(clen + 1);
                if (cbuf == NULL)
                    return (-2);
                memmove(cbuf, record, clen + 1);
                if (capdbp->close(capdbp) < 0) {
                    free(cbuf);
                    return (-2);
                }
                *len = clen;
                *cap = cbuf;
                return (retval);
            } else
#endif
            {
                fd = open(*db_p, O_RDONLY, 0);
                if (fd < 0) {
                    /* No error on unfound file. */
                    continue;
                }
                myfd = 1;
            }
        }
        /*
         * Find the requested capability record ...
         */
        {
            char buf[BUFSIZ];
            char *b_end, *bp, *cp;
            int c, slash;

            /*
             * Loop invariants:
             *  There is always room for one more character in record.
             *  R_end always points just past end of record.
             *  Rp always points just past last character in record.
             *  B_end always points just past last character in buf.
             *  Bp always points at next character in buf.
             *  Cp remembers where the last colon was.
             */
            b_end = buf;
            bp = buf;
            cp = 0;
            slash = 0;
            for (;;) {

                /*
                 * Read in a line implementing (\, newline)
                 * line continuation.
                 */
                rp = record;
                for (;;) {
                    if (bp >= b_end) {
                        int n;
                
                        n = read(fd, buf, sizeof(buf));
                        if (n <= 0) {
                            if (myfd)
                                (void)close(fd);
                            if (n < 0) {
                                free(record);
                                return (-2);
                            } else {
                                fd = -1;
                                eof = 1;
                                break;
                            }
                        }
                        b_end = buf+n;
                        bp = buf;
                    }
        
                    c = *bp++;
                    if (c == '\n') {
                        if (slash) {
                            slash = 0;
                            rp--;
                            continue;
                        } else
                            break;
                    }
                    if (slash) {
                        slash = 0;
                        cp = 0;
                    }
                    if (c == ':') {
                        /*
                         * If the field was `empty' (i.e.
                         * contained only white space), back up
                         * to the colon (eliminating the
                         * field).
                         */
                        if (cp)
                            rp = cp;
                        else
                            cp = rp;
                    } else if (c == '\\') {
                        slash = 1;
                    } else if (c != ' ' && c != '\t') {
                        /*
                         * Forget where the colon was, as this
                         * is not an empty field.
                         */
                        cp = 0;
                    }
                    *rp++ = c;

                                /*
                                 * Enforce loop invariant: if no room 
                                 * left in record buffer, try to get
                                 * some more.
                                 */
                    if (rp >= r_end) {
                        u_int pos;
                        size_t newsize;

                        pos = rp - record;
                        newsize = r_end - record + BFRAG;
                        record = realloc(record, newsize);
                        if (record == NULL) {
                            errno = ENOMEM;
                            if (myfd)
                                (void)close(fd);
                            return (-2);
                        }
                        r_end = record + newsize;
                        rp = record + pos;
                    }
                }
                /* Eliminate any white space after the last colon. */
                if (cp)
                    rp = cp + 1;
                /* Loop invariant lets us do this. */
                *rp++ = '\0';

                /*
                 * If encountered eof check next file.
                 */
                if (eof)
                    break;
                                
                /*
                 * Toss blank lines and comments.
                 */
                if (*record == '\0' || *record == '#')
                    continue;
        
                /*
                 * See if this is the record we want ...
                 */
                if (cgetmatch(record, name) == 0) {
                    if (nfield == NULL || !nfcmp(nfield, record)) {
                        foundit = 1;
                        break;  /* found it! */
                    }
                }
            }
        }
        if (foundit)
            break;
    }

    if (!foundit)
        return (-1);

    /*
     * Got the capability record, but now we have to expand all tc=name
     * references in it ...
     */
 tc_exp:        {
        char *newicap, *s;
        size_t ilen, newilen;
        int diff, iret, tclen;
        char *icap, *scan, *tc, *tcstart, *tcend;

        /*
         * Loop invariants:
         *      There is room for one more character in record.
         *      R_end points just past end of record.
         *      Rp points just past last character in record.
         *      Scan points at remainder of record that needs to be
         *      scanned for tc=name constructs.
         */
        scan = record;
        tc_not_resolved = 0;
        for (;;) {
            if ((tc = cgetcap(scan, "tc", '=')) == NULL)
                break;

            /*
             * Find end of tc=name and stomp on the trailing `:'
             * (if present) so we can use it to call ourselves.
             */
            s = tc;
            for (;;)
                if (*s == '\0')
                    break;
                else
                    if (*s++ == ':') {
                        *(s - 1) = '\0';
                        break;
                    }
            tcstart = tc - 3;
            tclen = s - tcstart;
            tcend = s;

            iret = getent(&icap, &ilen, db_p, fd, tc, depth+1, 
                          NULL);
            newicap = icap;             /* Put into a register. */
            newilen = ilen;
            if (iret != 0) {
                                /* an error */
                if (iret < -1) {
                    if (myfd)
                        (void)close(fd);
                    free(record);
                    return (iret);
                }
                if (iret == 1)
                    tc_not_resolved = 1;
                                /* couldn't resolve tc */
                if (iret == -1) {
                    *(s - 1) = ':';                     
                    scan = s - 1;
                    tc_not_resolved = 1;
                    continue;
                                        
                }
            }
            /* not interested in name field of tc'ed record */
            s = newicap;
            for (;;)
                if (*s == '\0')
                    break;
                else
                    if (*s++ == ':')
                        break;
            newilen -= s - newicap;
            newicap = s;

            /* make sure interpolated record is `:'-terminated */
            s += newilen;
            if (*(s-1) != ':') {
                *s = ':';       /* overwrite NUL with : */
                newilen++;
            }

            /*
             * Make sure there's enough room to insert the
             * new record.
             */
            diff = newilen - tclen;
            if (diff >= r_end - rp) {
                u_int pos, tcpos, tcposend;
                size_t newsize;

                pos = rp - record;
                newsize = r_end - record + diff + BFRAG;
                tcpos = tcstart - record;
                tcposend = tcend - record;
                record = realloc(record, newsize);
                if (record == NULL) {
                    errno = ENOMEM;
                    if (myfd)
                        (void)close(fd);
                    free(icap);
                    return (-2);
                }
                r_end = record + newsize;
                rp = record + pos;
                tcstart = record + tcpos;
                tcend = record + tcposend;
            }

            /*
             * Insert tc'ed record into our record.
             */
            s = tcstart + newilen;
            memmove(s, tcend,  (size_t)(rp - tcend));
            memmove(tcstart, newicap, newilen);
            rp += diff;
            free(icap);

            /*
             * Start scan on `:' so next cgetcap works properly
             * (cgetcap always skips first field).
             */
            scan = s-1;
        }
        
    }
    /*
     * Close file (if we opened it), give back any extra memory, and
     * return capability, length and success.
     */
    if (myfd)
        (void)close(fd);
    *len = rp - record - 1;     /* don't count NUL */
    if (r_end > rp)
        if ((record = 
             realloc(record, (size_t)(rp - record))) == NULL) {
            errno = ENOMEM;
            return (-2);
        }
                
    *cap = record;
    if (tc_not_resolved)
        return (1);
    return (0);
}       

#ifdef USE_DB
static int
cdbget(DB *capdbp, char **bp, const char *name)
{
        DBT key;
        DBT data;

        /* LINTED key is not modified */
        key.data = (char *)name;
        key.size = strlen(name);

        for (;;) {
                /* Get the reference. */
                switch(capdbp->get(capdbp, &key, &data, 0)) {
                case -1:
                        return (-2);
                case 1:
                        return (-1);
                }

                /* If not an index to another record, leave. */
                if (((char *)data.data)[0] != SHADOW)
                        break;

                key.data = (char *)data.data + 1;
                key.size = data.size - 1;
        }
        
        *bp = (char *)data.data + 1;
        return (((char *)(data.data))[0] == TCERR ? 1 : 0);
}
#endif /* USE_DB */

/*
 * Cgetmatch will return 0 if name is one of the names of the capability
 * record buf, -1 if not.
 */
int
cgetmatch(const char *buf, const char *name)
{
    const char *np, *bp;

    /*
     * Start search at beginning of record.
     */
    bp = buf;
    for (;;) {
        /*
         * Try to match a record name.
         */
        np = name;
        for (;;)
            if (*np == '\0') {
                if (*bp == '|' || *bp == ':' || *bp == '\0')
                    return (0);
                else
                    break;
            } else
                if (*bp++ != *np++)
                    break;

        /*
         * Match failed, skip to next name in record.
         */
        bp--;   /* a '|' or ':' may have stopped the match */
        for (;;)
            if (*bp == '\0' || *bp == ':')
                return (-1);    /* match failed totally */
            else
                if (*bp++ == '|')
                    break;      /* found next name */
    }
}

#if 0
int
cgetfirst(char **buf, char **db_array)
{
    (void)cgetclose();
    return (cgetnext(buf, db_array));
}
#endif

static FILE *pfp;
static int slash;
static char **dbp;

int ROKEN_LIB_FUNCTION
cgetclose(void)
{
    if (pfp != NULL) {
        (void)fclose(pfp);
        pfp = NULL;
    }
    dbp = NULL;
    gottoprec = 0;
    slash = 0;
    return(0);
}

#if 0
/*
 * Cgetnext() gets either the first or next entry in the logical database 
 * specified by db_array.  It returns 0 upon completion of the database, 1
 * upon returning an entry with more remaining, and -1 if an error occurs.
 */
int
cgetnext(char **bp, char **db_array)
{
    size_t len;
    int status, done;
    char *cp, *line, *rp, *np, buf[BSIZE], nbuf[BSIZE];
    size_t dummy;

    if (dbp == NULL)
        dbp = db_array;

    if (pfp == NULL && (pfp = fopen(*dbp, "r")) == NULL) {
        (void)cgetclose();
        return (-1);
    }
    for(;;) {
        if (toprec && !gottoprec) {
            gottoprec = 1;
            line = toprec;
        } else {
            line = fgetln(pfp, &len);
            if (line == NULL && pfp) {
                if (ferror(pfp)) {
                    (void)cgetclose();
                    return (-1);
                } else {
                    (void)fclose(pfp);
                    pfp = NULL;
                    if (*++dbp == NULL) {
                        (void)cgetclose();
                        return (0);
                    } else if ((pfp =
                                fopen(*dbp, "r")) == NULL) {
                        (void)cgetclose();
                        return (-1);
                    } else
                        continue;
                }
            } else
                line[len - 1] = '\0';
            if (len == 1) {
                slash = 0;
                continue;
            }
            if (isspace((unsigned char)*line) ||
                *line == ':' || *line == '#' || slash) {
                if (line[len - 2] == '\\')
                    slash = 1;
                else
                    slash = 0;
                continue;
            }
            if (line[len - 2] == '\\')
                slash = 1;
            else
                slash = 0;
        }                       


        /* 
         * Line points to a name line.
         */
        done = 0;
        np = nbuf;
        for (;;) {
            for (cp = line; *cp != '\0'; cp++) {
                if (*cp == ':') {
                    *np++ = ':';
                    done = 1;
                    break;
                }
                if (*cp == '\\')
                    break;
                *np++ = *cp;
            }
            if (done) {
                *np = '\0';
                break;
            } else { /* name field extends beyond the line */
                line = fgetln(pfp, &len);
                if (line == NULL && pfp) {
                    if (ferror(pfp)) {
                        (void)cgetclose();
                        return (-1);
                    }
                    (void)fclose(pfp);
                    pfp = NULL;
                    *np = '\0';
                    break;
                } else
                    line[len - 1] = '\0';
            }
        }
        rp = buf;
        for(cp = nbuf; *cp != '\0'; cp++)
            if (*cp == '|' || *cp == ':')
                break;
            else
                *rp++ = *cp;

        *rp = '\0';
        /* 
         * XXX 
         * Last argument of getent here should be nbuf if we want true
         * sequential access in the case of duplicates.  
         * With NULL, getent will return the first entry found
         * rather than the duplicate entry record.  This is a 
         * matter of semantics that should be resolved.
         */
        status = getent(bp, &dummy, db_array, -1, buf, 0, NULL);
        if (status == -2 || status == -3)
            (void)cgetclose();

        return (status + 1);
    }
    /* NOTREACHED */
}
#endif

/*
 * Cgetstr retrieves the value of the string capability cap from the
 * capability record pointed to by buf.  A pointer to a decoded, NUL
 * terminated, malloc'd copy of the string is returned in the char *
 * pointed to by str.  The length of the string not including the trailing
 * NUL is returned on success, -1 if the requested string capability
 * couldn't be found, -2 if a system error was encountered (storage
 * allocation failure).
 */
int ROKEN_LIB_FUNCTION
cgetstr(char *buf, const char *cap, char **str)
{
    u_int m_room;
    const char *bp;
    char *mp;
    int len;
    char *mem;

    /*
     * Find string capability cap
     */
    bp = cgetcap(buf, cap, '=');
    if (bp == NULL)
        return (-1);

    /*
     * Conversion / storage allocation loop ...  Allocate memory in
     * chunks SFRAG in size.
     */
    if ((mem = malloc(SFRAG)) == NULL) {
        errno = ENOMEM;
        return (-2);    /* couldn't even allocate the first fragment */
    }
    m_room = SFRAG;
    mp = mem;

    while (*bp != ':' && *bp != '\0') {
        /*
         * Loop invariants:
         *      There is always room for one more character in mem.
         *      Mp always points just past last character in mem.
         *      Bp always points at next character in buf.
         */
        if (*bp == '^') {
            bp++;
            if (*bp == ':' || *bp == '\0')
                break;  /* drop unfinished escape */
            *mp++ = *bp++ & 037;
        } else if (*bp == '\\') {
            bp++;
            if (*bp == ':' || *bp == '\0')
                break;  /* drop unfinished escape */
            if ('0' <= *bp && *bp <= '7') {
                int n, i;

                n = 0;
                i = 3;  /* maximum of three octal digits */
                do {
                    n = n * 8 + (*bp++ - '0');
                } while (--i && '0' <= *bp && *bp <= '7');
                *mp++ = n;
            }
            else switch (*bp++) {
            case 'b': case 'B':
                *mp++ = '\b';
                break;
            case 't': case 'T':
                *mp++ = '\t';
                break;
            case 'n': case 'N':
                *mp++ = '\n';
                break;
            case 'f': case 'F':
                *mp++ = '\f';
                break;
            case 'r': case 'R':
                *mp++ = '\r';
                break;
            case 'e': case 'E':
                *mp++ = ESC;
                break;
            case 'c': case 'C':
                *mp++ = ':';
                break;
            default:
                /*
                 * Catches '\', '^', and
                 *  everything else.
                 */
                *mp++ = *(bp-1);
                break;
            }
        } else
            *mp++ = *bp++;
        m_room--;

        /*
         * Enforce loop invariant: if no room left in current
         * buffer, try to get some more.
         */
        if (m_room == 0) {
            size_t size = mp - mem;

            if ((mem = realloc(mem, size + SFRAG)) == NULL)
                return (-2);
            m_room = SFRAG;
            mp = mem + size;
        }
    }
    *mp++ = '\0';       /* loop invariant let's us do this */
    m_room--;
    len = mp - mem - 1;

    /*
     * Give back any extra memory and return value and success.
     */
    if (m_room != 0)
        if ((mem = realloc(mem, (size_t)(mp - mem))) == NULL)
            return (-2);
    *str = mem;
    return (len);
}

/*
 * Cgetustr retrieves the value of the string capability cap from the
 * capability record pointed to by buf.  The difference between cgetustr()
 * and cgetstr() is that cgetustr does not decode escapes but rather treats
 * all characters literally.  A pointer to a  NUL terminated malloc'd 
 * copy of the string is returned in the char pointed to by str.  The 
 * length of the string not including the trailing NUL is returned on success,
 * -1 if the requested string capability couldn't be found, -2 if a system 
 * error was encountered (storage allocation failure).
 */
int ROKEN_LIB_FUNCTION
cgetustr(char *buf, const char *cap, char **str)
{
    u_int m_room;
    const char *bp;
    char *mp;
    int len;
    char *mem;

    /*
     * Find string capability cap
     */
    if ((bp = cgetcap(buf, cap, '=')) == NULL)
        return (-1);

    /*
     * Conversion / storage allocation loop ...  Allocate memory in
     * chunks SFRAG in size.
     */
    if ((mem = malloc(SFRAG)) == NULL) {
        errno = ENOMEM;
        return (-2);    /* couldn't even allocate the first fragment */
    }
    m_room = SFRAG;
    mp = mem;

    while (*bp != ':' && *bp != '\0') {
        /*
         * Loop invariants:
         *      There is always room for one more character in mem.
         *      Mp always points just past last character in mem.
         *      Bp always points at next character in buf.
         */
        *mp++ = *bp++;
        m_room--;

        /*
         * Enforce loop invariant: if no room left in current
         * buffer, try to get some more.
         */
        if (m_room == 0) {
            size_t size = mp - mem;

            if ((mem = realloc(mem, size + SFRAG)) == NULL)
                return (-2);
            m_room = SFRAG;
            mp = mem + size;
        }
    }
    *mp++ = '\0';       /* loop invariant let's us do this */
    m_room--;
    len = mp - mem - 1;

    /*
     * Give back any extra memory and return value and success.
     */
    if (m_room != 0)
        if ((mem = realloc(mem, (size_t)(mp - mem))) == NULL)
            return (-2);
    *str = mem;
    return (len);
}

/*
 * Cgetnum retrieves the value of the numeric capability cap from the
 * capability record pointed to by buf.  The numeric value is returned in
 * the long pointed to by num.  0 is returned on success, -1 if the requested
 * numeric capability couldn't be found.
 */
int ROKEN_LIB_FUNCTION
cgetnum(char *buf, const char *cap, long *num)
{
    long n;
    int base, digit;
    const char *bp;

    /*
     * Find numeric capability cap
     */
    bp = cgetcap(buf, cap, '#');
    if (bp == NULL)
        return (-1);

    /*
     * Look at value and determine numeric base:
     *  0x... or 0X...  hexadecimal,
     * else     0...            octal,
     * else                     decimal.
     */
    if (*bp == '0') {
        bp++;
        if (*bp == 'x' || *bp == 'X') {
            bp++;
            base = 16;
        } else
            base = 8;
    } else
        base = 10;

    /*
     * Conversion loop ...
     */
    n = 0;
    for (;;) {
        if ('0' <= *bp && *bp <= '9')
            digit = *bp - '0';
        else if ('a' <= *bp && *bp <= 'f')
            digit = 10 + *bp - 'a';
        else if ('A' <= *bp && *bp <= 'F')
            digit = 10 + *bp - 'A';
        else
            break;

        if (digit >= base)
            break;

        n = n * base + digit;
        bp++;
    }

    /*
     * Return value and success.
     */
    *num = n;
    return (0);
}


/*
 * Compare name field of record.
 */
static int
nfcmp(char *nf, char *rec)
{
    char *cp, tmp;
    int ret;
        
    for (cp = rec; *cp != ':'; cp++)
        ;
        
    tmp = *(cp + 1);
    *(cp + 1) = '\0';
    ret = strcmp(nf, rec);
    *(cp + 1) = tmp;

    return (ret);
}