xref: /netbsd-src/lib/libc/gen/scandir.c (revision d48f14661dda8638fee055ba15d35bdfb29b9fa8)
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