xref: /freebsd/lib/libc/gen/scandir.c (revision 42c159fe388a3765f69860c84183700af37aca8a)
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  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #if defined(LIBC_SCCS) && !defined(lint)
35 static char sccsid[] = "@(#)scandir.c	8.3 (Berkeley) 1/2/94";
36 #endif /* LIBC_SCCS and not lint */
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
39 
40 /*
41  * Scan the directory dirname calling select to make a list of selected
42  * directory entries then sort using qsort and compare routine dcomp.
43  * Returns the number of entries and a pointer to a list of pointers to
44  * struct dirent (through namelist). Returns -1 if there were any errors.
45  */
46 
47 #include "namespace.h"
48 #include <sys/types.h>
49 #include <sys/stat.h>
50 #include <dirent.h>
51 #include <stdlib.h>
52 #include <string.h>
53 #include "un-namespace.h"
54 
55 /*
56  * The DIRSIZ macro is the minimum record length which will hold the directory
57  * entry.  This requires the amount of space in struct dirent without the
58  * d_name field, plus enough space for the name and a terminating nul byte
59  * (dp->d_namlen + 1), rounded up to a 4 byte boundary.
60  */
61 #undef DIRSIZ
62 #define DIRSIZ(dp)							\
63 	((sizeof(struct dirent) - sizeof(dp)->d_name) +			\
64 	    (((dp)->d_namlen + 1 + 3) &~ 3))
65 
66 int
67 scandir(dirname, namelist, select, dcomp)
68 	const char *dirname;
69 	struct dirent ***namelist;
70 	int (*select)(struct dirent *);
71 	int (*dcomp)(const void *, const void *);
72 {
73 	struct dirent *d, *p, **names = NULL;
74 	size_t nitems = 0;
75 	struct stat stb;
76 	long arraysz;
77 	DIR *dirp;
78 
79 	if ((dirp = opendir(dirname)) == NULL)
80 		return(-1);
81 	if (_fstat(dirp->dd_fd, &stb) < 0)
82 		goto fail;
83 
84 	/*
85 	 * estimate the array size by taking the size of the directory file
86 	 * and dividing it by a multiple of the minimum size entry.
87 	 */
88 	arraysz = (stb.st_size / 24);
89 	names = (struct dirent **)malloc(arraysz * sizeof(struct dirent *));
90 	if (names == NULL)
91 		goto fail;
92 
93 	while ((d = readdir(dirp)) != NULL) {
94 		if (select != NULL && !(*select)(d))
95 			continue;	/* just selected names */
96 		/*
97 		 * Make a minimum size copy of the data
98 		 */
99 		p = (struct dirent *)malloc(DIRSIZ(d));
100 		if (p == NULL)
101 			goto fail;
102 		p->d_fileno = d->d_fileno;
103 		p->d_type = d->d_type;
104 		p->d_reclen = d->d_reclen;
105 		p->d_namlen = d->d_namlen;
106 		bcopy(d->d_name, p->d_name, p->d_namlen + 1);
107 		/*
108 		 * Check to make sure the array has space left and
109 		 * realloc the maximum size.
110 		 */
111 		if (nitems >= arraysz) {
112 			const int inc = 10;	/* increase by this much */
113 			struct dirent **names2;
114 
115 			names2 = (struct dirent **)realloc((char *)names,
116 				(arraysz + inc) * sizeof(struct dirent *));
117 			if (names2 == NULL) {
118 				free(p);
119 				goto fail;
120 			}
121 			names = names2;
122 			arraysz += inc;
123 		}
124 		names[nitems++] = p;
125 	}
126 	closedir(dirp);
127 	if (nitems && dcomp != NULL)
128 		qsort(names, nitems, sizeof(struct dirent *), dcomp);
129 	*namelist = names;
130 	return(nitems);
131 
132 fail:
133 	while (nitems > 0)
134 		free(names[--nitems]);
135 	free(names);
136 	closedir(dirp);
137 	return -1;
138 }
139 
140 /*
141  * Alphabetic order comparison routine for those who want it.
142  */
143 int
144 alphasort(d1, d2)
145 	const void *d1;
146 	const void *d2;
147 {
148 	return(strcmp((*(struct dirent **)d1)->d_name,
149 	    (*(struct dirent **)d2)->d_name));
150 }
151