1 /* $OpenBSD: scandir.c,v 1.21 2019/06/28 13:32:41 deraadt 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 <stdint.h>
43 #include <stdlib.h>
44 #include <string.h>
45 #include "telldir.h"
46
47 #define MAXIMUM(a, b) (((a) > (b)) ? (a) : (b))
48
49 /*
50 * The DIRSIZ macro is the minimum record length which will hold the directory
51 * entry. This requires the amount of space in struct dirent without the
52 * d_name field, plus enough space for the name and a terminating nul byte
53 * (dp->d_namlen + 1), rounded up to a 4 byte boundary.
54 */
55 #undef DIRSIZ
56 #define DIRSIZ(dp) \
57 ((sizeof(struct dirent) - sizeof(dp)->d_name) + \
58 (((dp)->d_namlen + 1 + 3) &~ 3))
59
60 int
scandir(const char * dirname,struct dirent *** namelist,int (* select)(const struct dirent *),int (* dcomp)(const struct dirent **,const struct dirent **))61 scandir(const char *dirname, struct dirent ***namelist,
62 int (*select)(const struct dirent *),
63 int (*dcomp)(const struct dirent **, const struct dirent **))
64 {
65 struct dirent *d, *p, **names = NULL;
66 size_t nitems = 0;
67 struct stat stb;
68 long arraysz;
69 DIR *dirp;
70
71 if ((dirp = opendir(dirname)) == NULL)
72 return (-1);
73 if (fstat(dirp->dd_fd, &stb) == -1)
74 goto fail;
75
76 /*
77 * estimate the array size by taking the size of the directory file
78 * and dividing it by a multiple of the minimum size entry.
79 */
80 arraysz = MAXIMUM(stb.st_size / 24, 16);
81 if (arraysz > SIZE_MAX / sizeof(struct dirent *)) {
82 errno = ENOMEM;
83 goto fail;
84 }
85 names = calloc(arraysz, sizeof(struct dirent *));
86 if (names == NULL)
87 goto fail;
88
89 while ((d = readdir(dirp)) != NULL) {
90 if (select != NULL && !(*select)(d))
91 continue; /* just selected names */
92
93 /*
94 * Check to make sure the array has space left and
95 * realloc the maximum size.
96 */
97 if (nitems >= arraysz) {
98 struct dirent **nnames;
99
100 if (fstat(dirp->dd_fd, &stb) == -1)
101 goto fail;
102
103 arraysz *= 2;
104 if (SIZE_MAX / sizeof(struct dirent *) < arraysz)
105 goto fail;
106 nnames = reallocarray(names,
107 arraysz, sizeof(struct dirent *));
108 if (nnames == NULL)
109 goto fail;
110
111 names = nnames;
112 }
113
114 /*
115 * Make a minimum size copy of the data
116 */
117 p = malloc(DIRSIZ(d));
118 if (p == NULL)
119 goto fail;
120
121 p->d_ino = d->d_ino;
122 p->d_type = d->d_type;
123 p->d_reclen = d->d_reclen;
124 p->d_namlen = d->d_namlen;
125 bcopy(d->d_name, p->d_name, p->d_namlen + 1);
126 names[nitems++] = p;
127 }
128 closedir(dirp);
129 if (nitems && dcomp != NULL)
130 qsort(names, nitems, sizeof(struct dirent *),
131 (int(*)(const void *, const void *))dcomp);
132 *namelist = names;
133 return (nitems);
134
135 fail:
136 while (nitems > 0)
137 free(names[--nitems]);
138 free(names);
139 closedir(dirp);
140 return (-1);
141 }
142
143 /*
144 * Alphabetic order comparison routine for those who want it.
145 */
146 int
alphasort(const struct dirent ** d1,const struct dirent ** d2)147 alphasort(const struct dirent **d1, const struct dirent **d2)
148 {
149 return(strcmp((*d1)->d_name, (*d2)->d_name));
150 }
151