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scandir.c revision 1.25 
      1 /*	$NetBSD: scandir.c,v 1.25 2005/09/13 01:44:09 christos Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1983, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 #if defined(LIBC_SCCS) && !defined(lint)
     34 #if 0
     35 static char sccsid[] = "@(#)scandir.c	8.3 (Berkeley) 1/2/94";
     36 #else
     37 __RCSID("$NetBSD: scandir.c,v 1.25 2005/09/13 01:44:09 christos Exp $");
     38 #endif
     39 #endif /* LIBC_SCCS and not lint */
     40 
     41 /*
     42  * Scan the directory dirname calling selectfn to make a list of selected
     43  * directory entries then sort using qsort and compare routine dcomp.
     44  * Returns the number of entries and a pointer to a list of pointers to
     45  * struct dirent (through namelist). Returns -1 if there were any errors.
     46  */
     47 
     48 #include "namespace.h"
     49 #include <sys/types.h>
     50 #include <sys/stat.h>
     51 
     52 #include <assert.h>
     53 #include <errno.h>
     54 #include <dirent.h>
     55 #include <stdlib.h>
     56 #include <string.h>
     57 
     58 int
     59 scandir(dirname, namelist, selectfn, dcomp)
     60 	const char *dirname;
     61 	struct dirent ***namelist;
     62 	int (*selectfn) __P((const struct dirent *));
     63 	int (*dcomp) __P((const void *, const void *));
     64 {
     65 	struct dirent *d, *p, **names, **newnames;
     66 	size_t nitems, arraysz;
     67 	struct stat stb;
     68 	DIR *dirp;
     69 
     70 	_DIAGASSERT(dirname != NULL);
     71 	_DIAGASSERT(namelist != NULL);
     72 
     73 	if ((dirp = opendir(dirname)) == NULL)
     74 		return (-1);
     75 	if (fstat(dirp->dd_fd, &stb) < 0)
     76 		goto bad;
     77 
     78 	/*
     79 	 * estimate the array size by taking the size of the directory file
     80 	 * and dividing it by a multiple of the minimum size entry.
     81 	 */
     82 	arraysz = (size_t)(stb.st_size / 24);
     83 	names = malloc(arraysz * sizeof(struct dirent *));
     84 	if (names == NULL)
     85 		goto bad;
     86 
     87 	nitems = 0;
     88 	while ((d = readdir(dirp)) != NULL) {
     89 		if (selectfn != NULL && !(*selectfn)(d))
     90 			continue;	/* just selected names */
     91 
     92 		/*
     93 		 * Check to make sure the array has space left and
     94 		 * realloc the maximum size.
     95 		 */
     96 		if (nitems >= arraysz) {
     97 			if (fstat(dirp->dd_fd, &stb) < 0)
     98 				goto bad2;	/* just might have grown */
     99 			arraysz = (size_t)(stb.st_size / 12);
    100 			newnames = realloc(names,
    101 			    arraysz * sizeof(struct dirent *));
    102 			if (newnames == NULL)
    103 				goto bad2;
    104 			names = newnames;
    105 		}
    106 
    107 		/*
    108 		 * Make a minimum size copy of the data
    109 		 */
    110 		p = (struct dirent *)malloc((size_t)_DIRENT_SIZE(d));
    111 		if (p == NULL)
    112 			goto bad2;
    113 		p->d_fileno = d->d_fileno;
    114 		p->d_reclen = d->d_reclen;
    115 		p->d_type = d->d_type;
    116 		p->d_namlen = d->d_namlen;
    117 		memmove(p->d_name, d->d_name, (size_t)(p->d_namlen + 1));
    118 		names[nitems++] = p;
    119 	}
    120 	closedir(dirp);
    121 	if (nitems && dcomp != NULL)
    122 		qsort(names, nitems, sizeof(struct dirent *), dcomp);
    123 	*namelist = names;
    124 	return (nitems);
    125 
    126 bad2:
    127 	while (nitems-- > 0)
    128 		free(names[nitems]);
    129 	free(names);
    130 bad:
    131 	closedir(dirp);
    132 	return (-1);
    133 }
    134