1 /* $NetBSD: scandir.c,v 1.30 2022/03/12 17:31:39 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 1.30 2022/03/12 17:31:39 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 /*
59 * Compute an estimate of the number of entries in a directory based on
60 * the file size. Returns the estimated number of entries or 0 on failure.
61 */
62 static size_t
dirsize(int fd,size_t olen)63 dirsize(int fd, size_t olen)
64 {
65 struct stat stb;
66 size_t nlen;
67
68 if (fstat(fd, &stb) == -1)
69 return 0;
70 /*
71 * Estimate the array size by taking the size of the directory file
72 * and dividing it by a multiple of the minimum size entry.
73 */
74 nlen = (size_t)(stb.st_size / _DIRENT_MINSIZE((struct dirent *)0));
75 /*
76 * If the size turns up 0, switch to an alternate strategy and use the
77 * file size as the number of entries like ZFS returns. If that turns
78 * out to be 0 too return a minimum of 10 entries, plus the old length.
79 */
80 if (nlen == 0)
81 nlen = (size_t)(stb.st_size ? stb.st_size : 10);
82 return olen + nlen;
83 }
84
85 #ifndef COMPARARG
86 #define COMPARARG struct dirent **
87 #endif
88
89 int
scandir(const char * dirname,struct dirent *** namelist,int (* selectfn)(const struct dirent *),int (* dcomp)(const COMPARARG,const COMPARARG))90 scandir(const char *dirname, struct dirent ***namelist,
91 int (*selectfn)(const struct dirent *),
92 int (*dcomp)(const COMPARARG, const COMPARARG))
93 {
94 struct dirent *d, *p, **names;
95 size_t nitems, arraysz;
96 DIR *dirp;
97 int serrno;
98
99 _DIAGASSERT(dirname != NULL);
100 _DIAGASSERT(namelist != NULL);
101
102 if ((dirp = opendir(dirname)) == NULL)
103 return -1;
104
105 if ((arraysz = dirsize(dirp->dd_fd, 0)) == 0)
106 goto bad;
107
108 names = NULL;
109 errno = reallocarr(&names, arraysz, sizeof(*names));
110 if (errno)
111 goto bad;
112
113 nitems = 0;
114 while ((d = readdir(dirp)) != NULL) {
115 if (selectfn != NULL && !(*selectfn)(d))
116 continue; /* just selected names */
117
118 /*
119 * Check to make sure the array has space left and
120 * realloc the maximum size.
121 */
122 if (nitems >= arraysz) {
123 if ((arraysz = dirsize(dirp->dd_fd, arraysz)) == 0)
124 goto bad2;
125 errno = reallocarr(&names, arraysz, sizeof(*names));
126 if (errno)
127 goto bad2;
128 }
129
130 /*
131 * Make a minimum size copy of the data
132 */
133 p = malloc((size_t)_DIRENT_SIZE(d));
134 if (p == NULL)
135 goto bad2;
136 p->d_fileno = d->d_fileno;
137 p->d_reclen = d->d_reclen;
138 p->d_type = d->d_type;
139 p->d_namlen = d->d_namlen;
140 (void)memmove(p->d_name, d->d_name, (size_t)(p->d_namlen + 1));
141 names[nitems++] = p;
142 }
143 (void)closedir(dirp);
144 if (nitems && dcomp != NULL)
145 qsort(names, nitems, sizeof(*names),
146 (int (*)(const void *, const void *))dcomp);
147 *namelist = names;
148 _DIAGASSERT(__type_fit(int, nitems));
149 return (int)nitems;
150
151 bad2:
152 serrno = errno;
153 while (nitems-- > 0)
154 free(names[nitems]);
155 free(names);
156 errno = serrno;
157 bad:
158 serrno = errno;
159 (void)closedir(dirp);
160 errno = serrno;
161 return -1;
162 }
163