lib/libc/gen/scandir.c

   1 /*
   2  * Copyright (c) 1983, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  * $FreeBSD: src/lib/libc/gen/scandir.c,v 1.5.6.1 2001/03/05 09:52:13 obrien Exp $
  34  * $DragonFly: src/lib/libc/gen/scandir.c,v 1.7 2005/08/27 20:23:05 joerg Exp $
  35  *
  36  * @(#)scandir.c        8.3 (Berkeley) 1/2/94
  37  */
  38
  39 /*
  40  * Scan the directory dirname calling select to make a list of selected
  41  * directory entries then sort using qsort and compare routine dcomp.
  42  * Returns the number of entries and a pointer to a list of pointers to
  43  * struct dirent (through namelist). Returns -1 if there were any errors.
  44  */
  45
  46 #include "namespace.h"
  47 #include <sys/types.h>
  48 #include <sys/stat.h>
  49 #include <dirent.h>
  50 #include <limits.h>
  51 #include <stdlib.h>
  52 #include <string.h>
  53 #include "un-namespace.h"
  54
  55 int
  56 scandir(const char *dirname, struct dirent ***namelist,
  57         int (*select)(struct dirent *), int (*dcomp)(const void *, const void *))
  58 {
  59         struct dirent *d, *p, **names = NULL;
  60         size_t arraysz, nitems = 0;
  61         struct stat stb;
  62         DIR *dirp;
  63
  64         if ((dirp = opendir(dirname)) == NULL)
  65                 return(-1);
  66         if (_fstat(dirp->dd_fd, &stb) < 0)
  67                 goto fail;
  68
  69         /*
  70          * Estimate the array size by taking the size of the directory file
  71          * and dividing it by a multiple of the minimum size entry.
  72          * Ensure that the size does fit into memory without overflooding.
  73          */
  74         if (stb.st_size / 24 > SIZE_T_MAX)
  75                 goto fail;
  76         arraysz = stb.st_size / 24;
  77         names = (struct dirent **)malloc(arraysz * sizeof(struct dirent *));
  78         if (names == NULL)
  79                 goto fail;
  80
  81         while ((d = readdir(dirp)) != NULL) {
  82                 if (select != NULL && !(*select)(d))
  83                         continue;       /* just selected names */
  84                 /*
  85                  * Make a minimum size copy of the data
  86                  */
  87                 p = (struct dirent *)malloc(_DIRENT_DIRSIZ(d));
  88                 if (p == NULL)
  89                         goto fail;
  90                 p->d_ino = d->d_ino;
  91                 p->d_type = d->d_type;
  92                 p->d_namlen = d->d_namlen;
  93                 bcopy(d->d_name, p->d_name, p->d_namlen + 1);
  94                 /*
  95                  * Check to make sure the array has space left and
  96                  * realloc the maximum size.
  97                  */
  98                 if (nitems >= arraysz) {
  99                         const int inc = 10;     /* increase by this much */
 100                         struct dirent **names2;
 101
 102                         names2 = (struct dirent **)realloc((char *)names,
 103                                 (arraysz + inc) * sizeof(struct dirent *));
 104                         if (names2 == NULL) {
 105                                 free(p);
 106                                 goto fail;
 107                         }
 108                         names = names2;
 109                         arraysz += inc;
 110                 }
 111                 names[nitems++] = p;
 112         }
 113         closedir(dirp);
 114         if (nitems && dcomp != NULL)
 115                 qsort(names, nitems, sizeof(struct dirent *), dcomp);
 116         *namelist = names;
 117         return(nitems);
 118
 119 fail:
 120         while (nitems > 0)
 121                 free(names[--nitems]);
 122         free(names);
 123         closedir(dirp);
 124         return -1;
 125 }
 126
 127 /*
 128  * Alphabetic order comparison routine for those who want it.
 129  */
 130 int
 131 alphasort(const void *d1, const void *d2)
 132 {
 133         return(strcmp((*(const struct dirent * const *)d1)->d_name,
 134             (*(const struct dirent * const *)d2)->d_name));
 135 }