xref: /freebsd/lib/libc/gen/scandir.c (revision 1670a1c2a47d10ecccd001970b859caf93cd3b6e)
1 /*
2  * Copyright (c) 1983, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 4. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #if defined(LIBC_SCCS) && !defined(lint)
31 static char sccsid[] = "@(#)scandir.c	8.3 (Berkeley) 1/2/94";
32 #endif /* LIBC_SCCS and not lint */
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
35 
36 /*
37  * Scan the directory dirname calling select to make a list of selected
38  * directory entries then sort using qsort and compare routine dcomp.
39  * Returns the number of entries and a pointer to a list of pointers to
40  * struct dirent (through namelist). Returns -1 if there were any errors.
41  */
42 
43 #include "namespace.h"
44 #include <dirent.h>
45 #include <stdlib.h>
46 #include <string.h>
47 #include "un-namespace.h"
48 
49 static int alphasort_thunk(void *thunk, const void *p1, const void *p2);
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 int
63 scandir(const char *dirname, struct dirent ***namelist,
64     int (*select)(const struct dirent *), int (*dcomp)(const struct dirent **,
65 	const struct dirent **))
66 {
67 	struct dirent *d, *p, **names = NULL;
68 	size_t nitems = 0;
69 	long arraysz;
70 	DIR *dirp;
71 
72 	if ((dirp = opendir(dirname)) == NULL)
73 		return(-1);
74 
75 	arraysz = 32;	/* initial estimate of the array size */
76 	names = (struct dirent **)malloc(arraysz * sizeof(struct dirent *));
77 	if (names == NULL)
78 		goto fail;
79 
80 	while ((d = readdir(dirp)) != NULL) {
81 		if (select != NULL && !(*select)(d))
82 			continue;	/* just selected names */
83 		/*
84 		 * Make a minimum size copy of the data
85 		 */
86 		p = (struct dirent *)malloc(DIRSIZ(d));
87 		if (p == NULL)
88 			goto fail;
89 		p->d_fileno = d->d_fileno;
90 		p->d_type = d->d_type;
91 		p->d_reclen = d->d_reclen;
92 		p->d_namlen = d->d_namlen;
93 		bcopy(d->d_name, p->d_name, p->d_namlen + 1);
94 		/*
95 		 * Check to make sure the array has space left and
96 		 * realloc the maximum size.
97 		 */
98 		if (nitems >= arraysz) {
99 			struct dirent **names2;
100 
101 			names2 = (struct dirent **)realloc((char *)names,
102 				(arraysz * 2) * sizeof(struct dirent *));
103 			if (names2 == NULL) {
104 				free(p);
105 				goto fail;
106 			}
107 			names = names2;
108 			arraysz *= 2;
109 		}
110 		names[nitems++] = p;
111 	}
112 	closedir(dirp);
113 	if (nitems && dcomp != NULL)
114 		qsort_r(names, nitems, sizeof(struct dirent *),
115 		    &dcomp, alphasort_thunk);
116 	*namelist = names;
117 	return (nitems);
118 
119 fail:
120 	while (nitems > 0)
121 		free(names[--nitems]);
122 	free(names);
123 	closedir(dirp);
124 	return (-1);
125 }
126 
127 /*
128  * Alphabetic order comparison routine for those who want it.
129  * POSIX 2008 requires that alphasort() uses strcoll().
130  */
131 int
132 alphasort(const struct dirent **d1, const struct dirent **d2)
133 {
134 
135 	return (strcoll((*d1)->d_name, (*d2)->d_name));
136 }
137 
138 static int
139 alphasort_thunk(void *thunk, const void *p1, const void *p2)
140 {
141 	int (*dc)(const struct dirent **, const struct dirent **);
142 
143 	dc = *(int (**)(const struct dirent **, const struct dirent **))thunk;
144 	return (dc((const struct dirent **)p1, (const struct dirent **)p2));
145 }
146