/*      $OpenBSD: glob.c,v 1.50 2020/10/13 04:42:28 guenther Exp $ */
/*
 * Copyright (c) 1989, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Guido van Rossum.
 *
 * 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.
 */

/*
 * glob(3) -- a superset of the one defined in POSIX 1003.2.
 *
 * The [!...] convention to negate a range is supported (SysV, Posix, ksh).
 *
 * Optional extra services, controlled by flags not defined by POSIX:
 *
 * GLOB_QUOTE:
 *      Escaping convention: \ inhibits any special meaning the following
 *      character might have (except \ at end of string is retained).
 * GLOB_MAGCHAR:
 *      Set in gl_flags if pattern contained a globbing character.
 * GLOB_NOMAGIC:
 *      Same as GLOB_NOCHECK, but it will only append pattern if it did
 *      not contain any magic characters.  [Used in csh style globbing]
 * GLOB_ALTDIRFUNC:
 *      Use alternately specified directory access functions.
 * GLOB_TILDE:
 *      expand ~user/foo to the /home/dir/of/user/foo
 * GLOB_BRACE:
 *      expand {1,2}{a,b} to 1a 1b 2a 2b
 * gl_matchc:
 *      Number of matches in the current invocation of glob.
 */

#include <sys/stat.h>

#include <ctype.h>
#include <dirent.h>
#include <errno.h>
#include <glob.h>
#include <limits.h>
#include <pwd.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "charclass.h"

#define DOLLAR          '$'
#define DOT             '.'
#define EOS             '\0'
#define LBRACKET        '['
#define NOT             '!'
#define QUESTION        '?'
#define QUOTE           '\\'
#define RANGE           '-'
#define RBRACKET        ']'
#define SEP             '/'
#define STAR            '*'
#define TILDE           '~'
#define UNDERSCORE      '_'
#define LBRACE          '{'
#define RBRACE          '}'
#define SLASH           '/'
#define COMMA           ','

#ifndef DEBUG

#define M_QUOTE         0x8000
#define M_PROTECT       0x4000
#define M_MASK          0xffff
#define M_ASCII         0x00ff

typedef u_short Char;

#else

#define M_QUOTE         0x80
#define M_PROTECT       0x40
#define M_MASK          0xff
#define M_ASCII         0x7f

typedef char Char;

#endif


#define CHAR(c)         ((Char)((c)&M_ASCII))
#define META(c)         ((Char)((c)|M_QUOTE))
#define M_ALL           META('*')
#define M_END           META(']')
#define M_NOT           META('!')
#define M_ONE           META('?')
#define M_RNG           META('-')
#define M_SET           META('[')
#define M_CLASS         META(':')
#define ismeta(c)       (((c)&M_QUOTE) != 0)

#define GLOB_LIMIT_MALLOC       65536
#define GLOB_LIMIT_STAT         2048
#define GLOB_LIMIT_READDIR      16384

struct glob_lim {
        size_t  glim_malloc;
        size_t  glim_stat;
        size_t  glim_readdir;
};

struct glob_path_stat {
        char            *gps_path;
        struct stat     *gps_stat;
};

static int       compare(const void *, const void *);
static int       compare_gps(const void *, const void *);
static int       g_Ctoc(const Char *, char *, size_t);
static int       g_lstat(Char *, struct stat *, glob_t *);
static DIR      *g_opendir(Char *, glob_t *);
static Char     *g_strchr(const Char *, int);
static int       g_strncmp(const Char *, const char *, size_t);
static int       g_stat(Char *, struct stat *, glob_t *);
static int       glob0(const Char *, glob_t *, struct glob_lim *);
static int       glob1(Char *, Char *, glob_t *, struct glob_lim *);
static int       glob2(Char *, Char *, Char *, Char *, Char *, Char *,
                    glob_t *, struct glob_lim *);
static int       glob3(Char *, Char *, Char *, Char *, Char *,
                    Char *, Char *, glob_t *, struct glob_lim *);
static int       globextend(const Char *, glob_t *, struct glob_lim *,
                    struct stat *);
static const Char *
                 globtilde(const Char *, Char *, size_t, glob_t *);
static int       globexp1(const Char *, glob_t *, struct glob_lim *);
static int       globexp2(const Char *, const Char *, glob_t *,
                    struct glob_lim *);
static int       match(Char *, Char *, Char *);
#ifdef DEBUG
static void      qprintf(const char *, Char *);
#endif

int
glob(const char *pattern, int flags, int (*errfunc)(const char *, int),
    glob_t *pglob)
{
        const u_char *patnext;
        int c;
        Char *bufnext, *bufend, patbuf[PATH_MAX];
        struct glob_lim limit = { 0, 0, 0 };

        patnext = (u_char *) pattern;
        if (!(flags & GLOB_APPEND)) {
                pglob->gl_pathc = 0;
                pglob->gl_pathv = NULL;
                pglob->gl_statv = NULL;
                if (!(flags & GLOB_DOOFFS))
                        pglob->gl_offs = 0;
        }
        pglob->gl_flags = flags & ~GLOB_MAGCHAR;
        pglob->gl_errfunc = errfunc;
        pglob->gl_matchc = 0;

        if (strnlen(pattern, PATH_MAX) == PATH_MAX)
                return(GLOB_NOMATCH);

        if (pglob->gl_offs >= SSIZE_MAX || pglob->gl_pathc >= SSIZE_MAX ||
            pglob->gl_pathc >= SSIZE_MAX - pglob->gl_offs - 1)
                return GLOB_NOSPACE;

        bufnext = patbuf;
        bufend = bufnext + PATH_MAX - 1;
        if (flags & GLOB_NOESCAPE)
                while (bufnext < bufend && (c = *patnext++) != EOS)
                        *bufnext++ = c;
        else {
                /* Protect the quoted characters. */
                while (bufnext < bufend && (c = *patnext++) != EOS)
                        if (c == QUOTE) {
                                if ((c = *patnext++) == EOS) {
                                        c = QUOTE;
                                        --patnext;
                                }
                                *bufnext++ = c | M_PROTECT;
                        } else
                                *bufnext++ = c;
        }
        *bufnext = EOS;

        if (flags & GLOB_BRACE)
                return globexp1(patbuf, pglob, &limit);
        else
                return glob0(patbuf, pglob, &limit);
}

/*
 * Expand recursively a glob {} pattern. When there is no more expansion
 * invoke the standard globbing routine to glob the rest of the magic
 * characters
 */
static int
globexp1(const Char *pattern, glob_t *pglob, struct glob_lim *limitp)
{
        const Char* ptr = pattern;

        /* Protect a single {}, for find(1), like csh */
        if (pattern[0] == LBRACE && pattern[1] == RBRACE && pattern[2] == EOS)
                return glob0(pattern, pglob, limitp);

        if ((ptr = (const Char *) g_strchr(ptr, LBRACE)) != NULL)
                return globexp2(ptr, pattern, pglob, limitp);

        return glob0(pattern, pglob, limitp);
}


/*
 * Recursive brace globbing helper. Tries to expand a single brace.
 * If it succeeds then it invokes globexp1 with the new pattern.
 * If it fails then it tries to glob the rest of the pattern and returns.
 */
static int
globexp2(const Char *ptr, const Char *pattern, glob_t *pglob,
    struct glob_lim *limitp)
{
        int     i, rv;
        Char   *lm, *ls;
        const Char *pe, *pm, *pl;
        Char    patbuf[PATH_MAX];

        /* copy part up to the brace */
        for (lm = patbuf, pm = pattern; pm != ptr; *lm++ = *pm++)
                ;
        *lm = EOS;
        ls = lm;

        /* Find the balanced brace */
        for (i = 0, pe = ++ptr; *pe; pe++)
                if (*pe == LBRACKET) {
                        /* Ignore everything between [] */
                        for (pm = pe++; *pe != RBRACKET && *pe != EOS; pe++)
                                ;
                        if (*pe == EOS) {
                                /*
                                 * We could not find a matching RBRACKET.
                                 * Ignore and just look for RBRACE
                                 */
                                pe = pm;
                        }
                } else if (*pe == LBRACE)
                        i++;
                else if (*pe == RBRACE) {
                        if (i == 0)
                                break;
                        i--;
                }

        /* Non matching braces; just glob the pattern */
        if (i != 0 || *pe == EOS)
                return glob0(patbuf, pglob, limitp);

        for (i = 0, pl = pm = ptr; pm <= pe; pm++) {
                switch (*pm) {
                case LBRACKET:
                        /* Ignore everything between [] */
                        for (pl = pm++; *pm != RBRACKET && *pm != EOS; pm++)
                                ;
                        if (*pm == EOS) {
                                /*
                                 * We could not find a matching RBRACKET.
                                 * Ignore and just look for RBRACE
                                 */
                                pm = pl;
                        }
                        break;

                case LBRACE:
                        i++;
                        break;

                case RBRACE:
                        if (i) {
                                i--;
                                break;
                        }
                        /* FALLTHROUGH */
                case COMMA:
                        if (i && *pm == COMMA)
                                break;
                        else {
                                /* Append the current string */
                                for (lm = ls; (pl < pm); *lm++ = *pl++)
                                        ;

                                /*
                                 * Append the rest of the pattern after the
                                 * closing brace
                                 */
                                for (pl = pe + 1; (*lm++ = *pl++) != EOS; )
                                        ;

                                /* Expand the current pattern */
#ifdef DEBUG
                                qprintf("globexp2:", patbuf);
#endif
                                rv = globexp1(patbuf, pglob, limitp);
                                if (rv && rv != GLOB_NOMATCH)
                                        return rv;

                                /* move after the comma, to the next string */
                                pl = pm + 1;
                        }
                        break;

                default:
                        break;
                }
        }
        return 0;
}



/*
 * expand tilde from the passwd file.
 */
static const Char *
globtilde(const Char *pattern, Char *patbuf, size_t patbuf_len, glob_t *pglob)
{
        struct passwd pwstore, *pwd = NULL;
        char *h, pwbuf[_PW_BUF_LEN];
        const Char *p;
        Char *b, *eb;

        if (*pattern != TILDE || !(pglob->gl_flags & GLOB_TILDE))
                return pattern;

        /* Copy up to the end of the string or / */
        eb = &patbuf[patbuf_len - 1];
        for (p = pattern + 1, h = (char *) patbuf;
            h < (char *)eb && *p && *p != SLASH; *h++ = *p++)
                ;

        *h = EOS;

#if 0
        if (h == (char *)eb)
                return what;
#endif

        if (((char *) patbuf)[0] == EOS) {
                /*
                 * handle a plain ~ or ~/ by expanding $HOME
                 * first and then trying the password file
                 */
                if (issetugid() != 0 || (h = getenv("HOME")) == NULL) {
                        getpwuid_r(getuid(), &pwstore, pwbuf, sizeof(pwbuf),
                            &pwd);
                        if (pwd == NULL)
                                return pattern;
                        else
                                h = pwd->pw_dir;
                }
        } else {
                /*
                 * Expand a ~user
                 */
                getpwnam_r((char *)patbuf, &pwstore, pwbuf, sizeof(pwbuf),
                    &pwd);
                if (pwd == NULL)
                        return pattern;
                else
                        h = pwd->pw_dir;
        }

        /* Copy the home directory */
        for (b = patbuf; b < eb && *h; *b++ = *h++)
                ;

        /* Append the rest of the pattern */
        while (b < eb && (*b++ = *p++) != EOS)
                ;
        *b = EOS;

        return patbuf;
}

static int
g_strncmp(const Char *s1, const char *s2, size_t n)
{
        int rv = 0;

        while (n--) {
                rv = *(Char *)s1 - *(const unsigned char *)s2++;
                if (rv)
                        break;
                if (*s1++ == '\0')
                        break;
        }
        return rv;
}

static int
g_charclass(const Char **patternp, Char **bufnextp)
{
        const Char *pattern = *patternp + 1;
        Char *bufnext = *bufnextp;
        const Char *colon;
        const struct cclass *cc;
        size_t len;

        if ((colon = g_strchr(pattern, ':')) == NULL || colon[1] != ']')
                return 1;       /* not a character class */

        len = (size_t)(colon - pattern);
        for (cc = cclasses; cc->name != NULL; cc++) {
                if (!g_strncmp(pattern, cc->name, len) && cc->name[len] == '\0')
                        break;
        }
        if (cc->name == NULL)
                return -1;      /* invalid character class */
        *bufnext++ = M_CLASS;
        *bufnext++ = (Char)(cc - &cclasses[0]);
        *bufnextp = bufnext;
        *patternp += len + 3;

        return 0;
}

/*
 * The main glob() routine: compiles the pattern (optionally processing
 * quotes), calls glob1() to do the real pattern matching, and finally
 * sorts the list (unless unsorted operation is requested).  Returns 0
 * if things went well, nonzero if errors occurred.  It is not an error
 * to find no matches.
 */
static int
glob0(const Char *pattern, glob_t *pglob, struct glob_lim *limitp)
{
        const Char *qpatnext;
        int c, err;
        size_t oldpathc;
        Char *bufnext, patbuf[PATH_MAX];

        qpatnext = globtilde(pattern, patbuf, PATH_MAX, pglob);
        oldpathc = pglob->gl_pathc;
        bufnext = patbuf;

        /* We don't need to check for buffer overflow any more. */
        while ((c = *qpatnext++) != EOS) {
                switch (c) {
                case LBRACKET:
                        c = *qpatnext;
                        if (c == NOT)
                                ++qpatnext;
                        if (*qpatnext == EOS ||
                            g_strchr(qpatnext+1, RBRACKET) == NULL) {
                                *bufnext++ = LBRACKET;
                                if (c == NOT)
                                        --qpatnext;
                                break;
                        }
                        *bufnext++ = M_SET;
                        if (c == NOT)
                                *bufnext++ = M_NOT;
                        c = *qpatnext++;
                        do {
                                if (c == LBRACKET && *qpatnext == ':') {
                                        do {
                                                err = g_charclass(&qpatnext,
                                                    &bufnext);
                                                if (err)
                                                        break;
                                                c = *qpatnext++;
                                        } while (c == LBRACKET && *qpatnext == ':');
                                        if (err == -1 &&
                                            !(pglob->gl_flags & GLOB_NOCHECK))
                                                return GLOB_NOMATCH;
                                        if (c == RBRACKET)
                                                break;
                                }
                                *bufnext++ = CHAR(c);
                                if (*qpatnext == RANGE &&
                                    (c = qpatnext[1]) != RBRACKET) {
                                        *bufnext++ = M_RNG;
                                        *bufnext++ = CHAR(c);
                                        qpatnext += 2;
                                }
                        } while ((c = *qpatnext++) != RBRACKET);
                        pglob->gl_flags |= GLOB_MAGCHAR;
                        *bufnext++ = M_END;
                        break;
                case QUESTION:
                        pglob->gl_flags |= GLOB_MAGCHAR;
                        *bufnext++ = M_ONE;
                        break;
                case STAR:
                        pglob->gl_flags |= GLOB_MAGCHAR;
                        /* collapse adjacent stars to one,
                         * to avoid exponential behavior
                         */
                        if (bufnext == patbuf || bufnext[-1] != M_ALL)
                                *bufnext++ = M_ALL;
                        break;
                default:
                        *bufnext++ = CHAR(c);
                        break;
                }
        }
        *bufnext = EOS;
#ifdef DEBUG
        qprintf("glob0:", patbuf);
#endif

        if ((err = glob1(patbuf, patbuf+PATH_MAX-1, pglob, limitp)) != 0)
                return(err);

        /*
         * If there was no match we are going to append the pattern
         * if GLOB_NOCHECK was specified or if GLOB_NOMAGIC was specified
         * and the pattern did not contain any magic characters
         * GLOB_NOMAGIC is there just for compatibility with csh.
         */
        if (pglob->gl_pathc == oldpathc) {
                if ((pglob->gl_flags & GLOB_NOCHECK) ||
                    ((pglob->gl_flags & GLOB_NOMAGIC) &&
                    !(pglob->gl_flags & GLOB_MAGCHAR)))
                        return(globextend(pattern, pglob, limitp, NULL));
                else
                        return(GLOB_NOMATCH);
        }
        if (!(pglob->gl_flags & GLOB_NOSORT)) {
                if ((pglob->gl_flags & GLOB_KEEPSTAT)) {
                        /* Keep the paths and stat info synced during sort */
                        struct glob_path_stat *path_stat;
                        size_t i;
                        size_t n = pglob->gl_pathc - oldpathc;
                        size_t o = pglob->gl_offs + oldpathc;

                        if ((path_stat = calloc(n, sizeof(*path_stat))) == NULL)
                                return GLOB_NOSPACE;
                        for (i = 0; i < n; i++) {
                                path_stat[i].gps_path = pglob->gl_pathv[o + i];
                                path_stat[i].gps_stat = pglob->gl_statv[o + i];
                        }
                        qsort(path_stat, n, sizeof(*path_stat), compare_gps);
                        for (i = 0; i < n; i++) {
                                pglob->gl_pathv[o + i] = path_stat[i].gps_path;
                                pglob->gl_statv[o + i] = path_stat[i].gps_stat;
                        }
                        free(path_stat);
                } else {
                        qsort(pglob->gl_pathv + pglob->gl_offs + oldpathc,
                            pglob->gl_pathc - oldpathc, sizeof(char *),
                            compare);
                }
        }
        return(0);
}

static int
compare(const void *p, const void *q)
{
        return(strcmp(*(char **)p, *(char **)q));
}

static int
compare_gps(const void *_p, const void *_q)
{
        const struct glob_path_stat *p = (const struct glob_path_stat *)_p;
        const struct glob_path_stat *q = (const struct glob_path_stat *)_q;

        return(strcmp(p->gps_path, q->gps_path));
}

static int
glob1(Char *pattern, Char *pattern_last, glob_t *pglob, struct glob_lim *limitp)
{
        Char pathbuf[PATH_MAX];

        /* A null pathname is invalid -- POSIX 1003.1 sect. 2.4. */
        if (*pattern == EOS)
                return(0);
        return(glob2(pathbuf, pathbuf+PATH_MAX-1,
            pathbuf, pathbuf+PATH_MAX-1,
            pattern, pattern_last, pglob, limitp));
}

/*
 * The functions glob2 and glob3 are mutually recursive; there is one level
 * of recursion for each segment in the pattern that contains one or more
 * meta characters.
 */
static int
glob2(Char *pathbuf, Char *pathbuf_last, Char *pathend, Char *pathend_last,
    Char *pattern, Char *pattern_last, glob_t *pglob, struct glob_lim *limitp)
{
        struct stat sb;
        Char *p, *q;
        int anymeta;

        /*
         * Loop over pattern segments until end of pattern or until
         * segment with meta character found.
         */
        for (anymeta = 0;;) {
                if (*pattern == EOS) {          /* End of pattern? */
                        *pathend = EOS;

                        if ((pglob->gl_flags & GLOB_LIMIT) &&
                            limitp->glim_stat++ >= GLOB_LIMIT_STAT) {
                                errno = 0;
                                *pathend++ = SEP;
                                *pathend = EOS;
                                return(GLOB_NOSPACE);
                        }
                        if (g_lstat(pathbuf, &sb, pglob))
                                return(0);

                        if (((pglob->gl_flags & GLOB_MARK) &&
                            pathend[-1] != SEP) && (S_ISDIR(sb.st_mode) ||
                            (S_ISLNK(sb.st_mode) &&
                            (g_stat(pathbuf, &sb, pglob) == 0) &&
                            S_ISDIR(sb.st_mode)))) {
                                if (pathend+1 > pathend_last)
                                        return (1);
                                *pathend++ = SEP;
                                *pathend = EOS;
                        }
                        ++pglob->gl_matchc;
                        return(globextend(pathbuf, pglob, limitp, &sb));
                }

                /* Find end of next segment, copy tentatively to pathend. */
                q = pathend;
                p = pattern;
                while (*p != EOS && *p != SEP) {
                        if (ismeta(*p))
                                anymeta = 1;
                        if (q+1 > pathend_last)
                                return (1);
                        *q++ = *p++;
                }

                if (!anymeta) {         /* No expansion, do next segment. */
                        pathend = q;
                        pattern = p;
                        while (*pattern == SEP) {
                                if (pathend+1 > pathend_last)
                                        return (1);
                                *pathend++ = *pattern++;
                        }
                } else
                        /* Need expansion, recurse. */
                        return(glob3(pathbuf, pathbuf_last, pathend,
                            pathend_last, pattern, p, pattern_last,
                            pglob, limitp));
        }
        /* NOTREACHED */
}

static int
glob3(Char *pathbuf, Char *pathbuf_last, Char *pathend, Char *pathend_last,
    Char *pattern, Char *restpattern, Char *restpattern_last, glob_t *pglob,
    struct glob_lim *limitp)
{
        struct dirent *dp;
        DIR *dirp;
        int err;
        char buf[PATH_MAX];

        /*
         * The readdirfunc declaration can't be prototyped, because it is
         * assigned, below, to two functions which are prototyped in glob.h
         * and dirent.h as taking pointers to differently typed opaque
         * structures.
         */
        struct dirent *(*readdirfunc)(void *);

        if (pathend > pathend_last)
                return (1);
        *pathend = EOS;
        errno = 0;

        if ((dirp = g_opendir(pathbuf, pglob)) == NULL) {
                /* TODO: don't call for ENOENT or ENOTDIR? */
                if (pglob->gl_errfunc) {
                        if (g_Ctoc(pathbuf, buf, sizeof(buf)))
                                return(GLOB_ABORTED);
                        if (pglob->gl_errfunc(buf, errno) ||
                            pglob->gl_flags & GLOB_ERR)
                                return(GLOB_ABORTED);
                }
                return(0);
        }

        err = 0;

        /* Search directory for matching names. */
        if (pglob->gl_flags & GLOB_ALTDIRFUNC)
                readdirfunc = pglob->gl_readdir;
        else
                readdirfunc = (struct dirent *(*)(void *))readdir;
        while ((dp = (*readdirfunc)(dirp))) {
                u_char *sc;
                Char *dc;

                if ((pglob->gl_flags & GLOB_LIMIT) &&
                    limitp->glim_readdir++ >= GLOB_LIMIT_READDIR) {
                        errno = 0;
                        *pathend++ = SEP;
                        *pathend = EOS;
                        err = GLOB_NOSPACE;
                        break;
                }

                /* Initial DOT must be matched literally. */
                if (dp->d_name[0] == DOT && *pattern != DOT)
                        continue;
                dc = pathend;
                sc = (u_char *) dp->d_name;
                while (dc < pathend_last && (*dc++ = *sc++) != EOS)
                        ;
                if (dc >= pathend_last) {
                        *dc = EOS;
                        err = 1;
                        break;
                }

                if (!match(pathend, pattern, restpattern)) {
                        *pathend = EOS;
                        continue;
                }
                err = glob2(pathbuf, pathbuf_last, --dc, pathend_last,
                    restpattern, restpattern_last, pglob, limitp);
                if (err)
                        break;
        }

        if (pglob->gl_flags & GLOB_ALTDIRFUNC)
                (*pglob->gl_closedir)(dirp);
        else
                closedir(dirp);
        return(err);
}


/*
 * Extend the gl_pathv member of a glob_t structure to accommodate a new item,
 * add the new item, and update gl_pathc.
 *
 * This assumes the BSD realloc, which only copies the block when its size
 * crosses a power-of-two boundary; for v7 realloc, this would cause quadratic
 * behavior.
 *
 * Return 0 if new item added, error code if memory couldn't be allocated.
 *
 * Invariant of the glob_t structure:
 *      Either gl_pathc is zero and gl_pathv is NULL; or gl_pathc > 0 and
 *      gl_pathv points to (gl_offs + gl_pathc + 1) items.
 */
static int
globextend(const Char *path, glob_t *pglob, struct glob_lim *limitp,
    struct stat *sb)
{
        char **pathv;
        size_t i, newn, len;
        char *copy = NULL;
        const Char *p;
        struct stat **statv;

        newn = 2 + pglob->gl_pathc + pglob->gl_offs;
        if (pglob->gl_offs >= SSIZE_MAX ||
            pglob->gl_pathc >= SSIZE_MAX ||
            newn >= SSIZE_MAX ||
            SIZE_MAX / sizeof(*pathv) <= newn ||
            SIZE_MAX / sizeof(*statv) <= newn) {
 nospace:
                for (i = pglob->gl_offs; i < newn - 2; i++) {
                        if (pglob->gl_pathv && pglob->gl_pathv[i])
                                free(pglob->gl_pathv[i]);
                        if ((pglob->gl_flags & GLOB_KEEPSTAT) != 0 &&
                            pglob->gl_pathv && pglob->gl_pathv[i])
                                free(pglob->gl_statv[i]);
                }
                free(pglob->gl_pathv);
                pglob->gl_pathv = NULL;
                free(pglob->gl_statv);
                pglob->gl_statv = NULL;
                return(GLOB_NOSPACE);
        }

        pathv = reallocarray(pglob->gl_pathv, newn, sizeof(*pathv));
        if (pathv == NULL)
                goto nospace;
        if (pglob->gl_pathv == NULL && pglob->gl_offs > 0) {
                /* first time around -- clear initial gl_offs items */
                pathv += pglob->gl_offs;
                for (i = pglob->gl_offs; i > 0; i--)
                        *--pathv = NULL;
        }
        pglob->gl_pathv = pathv;

        if ((pglob->gl_flags & GLOB_KEEPSTAT) != 0) {
                statv = reallocarray(pglob->gl_statv, newn, sizeof(*statv));
                if (statv == NULL)
                        goto nospace;
                if (pglob->gl_statv == NULL && pglob->gl_offs > 0) {
                        /* first time around -- clear initial gl_offs items */
                        statv += pglob->gl_offs;
                        for (i = pglob->gl_offs; i > 0; i--)
                                *--statv = NULL;
                }
                pglob->gl_statv = statv;
                if (sb == NULL)
                        statv[pglob->gl_offs + pglob->gl_pathc] = NULL;
                else {
                        limitp->glim_malloc += sizeof(**statv);
                        if ((pglob->gl_flags & GLOB_LIMIT) &&
                            limitp->glim_malloc >= GLOB_LIMIT_MALLOC) {
                                errno = 0;
                                return(GLOB_NOSPACE);
                        }
                        if ((statv[pglob->gl_offs + pglob->gl_pathc] =
                            malloc(sizeof(**statv))) == NULL)
                                goto copy_error;
                        memcpy(statv[pglob->gl_offs + pglob->gl_pathc], sb,
                            sizeof(*sb));
                }
                statv[pglob->gl_offs + pglob->gl_pathc + 1] = NULL;
        }

        for (p = path; *p++;)
                ;
        len = (size_t)(p - path);
        limitp->glim_malloc += len;
        if ((copy = malloc(len)) != NULL) {
                if (g_Ctoc(path, copy, len)) {
                        free(copy);
                        return(GLOB_NOSPACE);
                }
                pathv[pglob->gl_offs + pglob->gl_pathc++] = copy;
        }
        pathv[pglob->gl_offs + pglob->gl_pathc] = NULL;

        if ((pglob->gl_flags & GLOB_LIMIT) &&
            (newn * sizeof(*pathv)) + limitp->glim_malloc >
            GLOB_LIMIT_MALLOC) {
                errno = 0;
                return(GLOB_NOSPACE);
        }
 copy_error:
        return(copy == NULL ? GLOB_NOSPACE : 0);
}


/*
 * pattern matching function for filenames.  Each occurrence of the *
 * pattern causes an iteration.
 *
 * Note, this function differs from the original as per the discussion
 * here: https://research.swtch.com/glob
 *
 * Basically we removed the recursion and made it use the algorithm
 * from Russ Cox to not go quadratic on cases like a file called
 * ("a" x 100) . "x" matched against a pattern like "a*a*a*a*a*a*a*y".
 */
static int
match(Char *name, Char *pat, Char *patend)
{
        int ok, negate_range;
        Char c, k;
        Char *nextp = NULL;
        Char *nextn = NULL;

loop:
        while (pat < patend) {
                c = *pat++;
                switch (c & M_MASK) {
                case M_ALL:
                        while (pat < patend && (*pat & M_MASK) == M_ALL)
                                pat++;  /* eat consecutive '*' */
                        if (pat == patend)
                                return(1);
                        if (*name == EOS)
                                return(0);
                        nextn = name + 1;
                        nextp = pat - 1;
                        break;
                case M_ONE:
                        if (*name++ == EOS)
                                goto fail;
                        break;
                case M_SET:
                        ok = 0;
                        if ((k = *name++) == EOS)
                                goto fail;
                        if ((negate_range = ((*pat & M_MASK) == M_NOT)) != EOS)
                                ++pat;
                        while (((c = *pat++) & M_MASK) != M_END) {
                                if ((c & M_MASK) == M_CLASS) {
                                        Char idx = *pat & M_MASK;
                                        if (idx < NCCLASSES &&
                                            cclasses[idx].isctype(k))
                                                ok = 1;
                                        ++pat;
                                }
                                if ((*pat & M_MASK) == M_RNG) {
                                        if (c <= k && k <= pat[1])
                                                ok = 1;
                                        pat += 2;
                                } else if (c == k)
                                        ok = 1;
                        }
                        if (ok == negate_range)
                                goto fail;
                        break;
                default:
                        if (*name++ != c)
                                goto fail;
                        break;
                }
        }
        if (*name == EOS)
                return(1);

fail:
        if (nextn) {
                pat = nextp;
                name = nextn;
                goto loop;
        }
        return(0);
}

/* Free allocated data belonging to a glob_t structure. */
void
globfree(glob_t *pglob)
{
        size_t i;
        char **pp;

        if (pglob->gl_pathv != NULL) {
                pp = pglob->gl_pathv + pglob->gl_offs;
                for (i = pglob->gl_pathc; i--; ++pp)
                        free(*pp);
                free(pglob->gl_pathv);
                pglob->gl_pathv = NULL;
        }
        if (pglob->gl_statv != NULL) {
                for (i = 0; i < pglob->gl_pathc; i++) {
                        free(pglob->gl_statv[i]);
                }
                free(pglob->gl_statv);
                pglob->gl_statv = NULL;
        }
}

static DIR *
g_opendir(Char *str, glob_t *pglob)
{
        char buf[PATH_MAX];

        if (!*str)
                strlcpy(buf, ".", sizeof buf);
        else {
                if (g_Ctoc(str, buf, sizeof(buf)))
                        return(NULL);
        }

        if (pglob->gl_flags & GLOB_ALTDIRFUNC)
                return((*pglob->gl_opendir)(buf));

        return(opendir(buf));
}

static int
g_lstat(Char *fn, struct stat *sb, glob_t *pglob)
{
        char buf[PATH_MAX];

        if (g_Ctoc(fn, buf, sizeof(buf)))
                return(-1);
        if (pglob->gl_flags & GLOB_ALTDIRFUNC)
                return((*pglob->gl_lstat)(buf, sb));
        return(lstat(buf, sb));
}

static int
g_stat(Char *fn, struct stat *sb, glob_t *pglob)
{
        char buf[PATH_MAX];

        if (g_Ctoc(fn, buf, sizeof(buf)))
                return(-1);
        if (pglob->gl_flags & GLOB_ALTDIRFUNC)
                return((*pglob->gl_stat)(buf, sb));
        return(stat(buf, sb));
}

static Char *
g_strchr(const Char *str, int ch)
{
        do {
                if (*str == ch)
                        return ((Char *)str);
        } while (*str++);
        return (NULL);
}

static int
g_Ctoc(const Char *str, char *buf, size_t len)
{

        while (len--) {
                if ((*buf++ = *str++) == EOS)
                        return (0);
        }
        return (1);
}

#ifdef DEBUG
static void
qprintf(const char *str, Char *s)
{
        Char *p;

        (void)printf("%s:\n", str);
        for (p = s; *p; p++)
                (void)printf("%c", CHAR(*p));
        (void)printf("\n");
        for (p = s; *p; p++)
                (void)printf("%c", *p & M_PROTECT ? '"' : ' ');
        (void)printf("\n");
        for (p = s; *p; p++)
                (void)printf("%c", ismeta(*p) ? '_' : ' ');
        (void)printf("\n");
}
#endif