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