1 /* $OpenBSD: scandir.c,v 1.23 2024/04/15 15:47:58 florian Exp $ */
2 /*
3 * Copyright (c) 1983, 1993
4 * The Regents of the University of California. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the University nor the names of its contributors
15 * may be used to endorse or promote products derived from this software
16 * without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31 /*
32 * Scan the directory dirname calling select to make a list of selected
33 * directory entries then sort using qsort and compare routine dcomp.
34 * Returns the number of entries and a pointer to a list of pointers to
35 * struct dirent (through namelist). Returns -1 if there were any errors.
36 */
37
38 #include <sys/types.h>
39 #include <sys/stat.h>
40 #include <dirent.h>
41 #include <errno.h>
42 #include <fcntl.h>
43 #include <stdint.h>
44 #include <stdlib.h>
45 #include <string.h>
46 #include <unistd.h>
47 #include "telldir.h"
48
49 #define MAXIMUM(a, b) (((a) > (b)) ? (a) : (b))
50
51 /*
52 * The DIRSIZ macro is the minimum record length which will hold the directory
53 * entry. This requires the amount of space in struct dirent without the
54 * d_name field, plus enough space for the name and a terminating nul byte
55 * (dp->d_namlen + 1), rounded up to a 4 byte boundary.
56 */
57 #undef DIRSIZ
58 #define DIRSIZ(dp) \
59 ((sizeof(struct dirent) - sizeof(dp)->d_name) + \
60 (((dp)->d_namlen + 1 + 3) &~ 3))
61
62 static int
scandir_dirp(DIR * dirp,struct dirent *** namelist,int (* select)(const struct dirent *),int (* dcomp)(const struct dirent **,const struct dirent **))63 scandir_dirp(DIR *dirp, struct dirent ***namelist,
64 int (*select)(const struct dirent *),
65 int (*dcomp)(const struct dirent **, const struct dirent **))
66 {
67 struct dirent *d, *p, **names = NULL;
68 size_t nitems = 0;
69 struct stat stb;
70 long arraysz;
71
72 if (fstat(dirp->dd_fd, &stb) == -1)
73 goto fail;
74
75 /*
76 * estimate the array size by taking the size of the directory file
77 * and dividing it by a multiple of the minimum size entry.
78 */
79 arraysz = MAXIMUM(stb.st_size / 24, 16);
80 if (arraysz > SIZE_MAX / sizeof(struct dirent *)) {
81 errno = ENOMEM;
82 goto fail;
83 }
84 names = calloc(arraysz, sizeof(struct dirent *));
85 if (names == NULL)
86 goto fail;
87
88 while ((d = readdir(dirp)) != NULL) {
89 if (select != NULL && !(*select)(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 struct dirent **nnames;
98
99 if (fstat(dirp->dd_fd, &stb) == -1)
100 goto fail;
101
102 arraysz *= 2;
103 if (SIZE_MAX / sizeof(struct dirent *) < arraysz)
104 goto fail;
105 nnames = reallocarray(names,
106 arraysz, sizeof(struct dirent *));
107 if (nnames == NULL)
108 goto fail;
109
110 names = nnames;
111 }
112
113 /*
114 * Make a minimum size copy of the data
115 */
116 p = malloc(DIRSIZ(d));
117 if (p == NULL)
118 goto fail;
119
120 p->d_ino = d->d_ino;
121 p->d_type = d->d_type;
122 p->d_reclen = d->d_reclen;
123 p->d_namlen = d->d_namlen;
124 bcopy(d->d_name, p->d_name, p->d_namlen + 1);
125 names[nitems++] = p;
126 }
127 closedir(dirp);
128 if (nitems && dcomp != NULL)
129 qsort(names, nitems, sizeof(struct dirent *),
130 (int(*)(const void *, const void *))dcomp);
131 *namelist = names;
132 return (nitems);
133
134 fail:
135 while (nitems > 0)
136 free(names[--nitems]);
137 free(names);
138 closedir(dirp);
139 return (-1);
140 }
141
142 int
scandir(const char * dirname,struct dirent *** namelist,int (* select)(const struct dirent *),int (* dcomp)(const struct dirent **,const struct dirent **))143 scandir(const char *dirname, struct dirent ***namelist,
144 int (*select)(const struct dirent *),
145 int (*dcomp)(const struct dirent **, const struct dirent **))
146 {
147 DIR *dirp;
148
149 if ((dirp = opendir(dirname)) == NULL)
150 return (-1);
151
152 return (scandir_dirp(dirp, namelist, select, dcomp));
153 }
154
155 int
scandirat(int dirfd,const char * dirname,struct dirent *** namelist,int (* select)(const struct dirent *),int (* dcomp)(const struct dirent **,const struct dirent **))156 scandirat(int dirfd, const char *dirname, struct dirent ***namelist,
157 int (*select)(const struct dirent *),
158 int (*dcomp)(const struct dirent **, const struct dirent **))
159 {
160 DIR *dirp;
161 int fd;
162
163 fd = HIDDEN(openat)(dirfd, dirname, O_RDONLY | O_DIRECTORY | O_CLOEXEC);
164 if (fd == -1)
165 return (-1);
166 dirp = __fdopendir(fd);
167 if (dirp == NULL) {
168 HIDDEN(close)(fd);
169 return (-1);
170 }
171 return (scandir_dirp(dirp, namelist, select, dcomp));
172 }
173
174 /*
175 * Alphabetic order comparison routine for those who want it.
176 */
177 int
alphasort(const struct dirent ** d1,const struct dirent ** d2)178 alphasort(const struct dirent **d1, const struct dirent **d2)
179 {
180 return(strcmp((*d1)->d_name, (*d2)->d_name));
181 }
182