xref: /netbsd-src/lib/libc/gen/scandir.c (revision d9158b13b5dfe46201430699a3f7a235ecf28df3)
1 /*
2  * Copyright (c) 1983 Regents of the University of California.
3  * 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 = "from: @(#)scandir.c	5.10 (Berkeley) 2/23/91";*/
36 static char *rcsid = "$Id: scandir.c,v 1.3 1993/08/26 00:45:00 jtc Exp $";
37 #endif /* LIBC_SCCS and not lint */
38 
39 /*
40  * Scan the directory dirname calling select to make a list of selected
41  * directory entries then sort using qsort and compare routine dcomp.
42  * Returns the number of entries and a pointer to a list of pointers to
43  * struct dirent (through namelist). Returns -1 if there were any errors.
44  */
45 
46 #include <sys/types.h>
47 #include <sys/stat.h>
48 #include <dirent.h>
49 #include <stdlib.h>
50 #include <string.h>
51 
52 /*
53  * The DIRSIZ macro gives the minimum record length which will hold
54  * the directory entry.  This requires the amount of space in struct dirent
55  * without the d_name field, plus enough space for the name with a terminating
56  * null byte (dp->d_namlen+1), rounded up to a 4 byte boundary.
57  */
58 #undef DIRSIZ
59 #define DIRSIZ(dp) \
60     ((sizeof (struct dirent) - (MAXNAMLEN+1)) + (((dp)->d_namlen+1 + 3) &~ 3))
61 
62 int
63 scandir(dirname, namelist, select, dcomp)
64 	const char *dirname;
65 	struct dirent ***namelist;
66 	int (*select) __P((struct dirent *));
67 	int (*dcomp) __P((const void *, const void *));
68 {
69 	register struct dirent *d, *p, **names;
70 	register size_t nitems;
71 	struct stat stb;
72 	long arraysz;
73 	DIR *dirp;
74 
75 	if ((dirp = opendir(dirname)) == NULL)
76 		return(-1);
77 	if (fstat(dirp->dd_fd, &stb) < 0)
78 		return(-1);
79 
80 	/*
81 	 * estimate the array size by taking the size of the directory file
82 	 * and dividing it by a multiple of the minimum size entry.
83 	 */
84 	arraysz = (stb.st_size / 24);
85 	names = (struct dirent **)malloc(arraysz * sizeof(struct dirent *));
86 	if (names == NULL)
87 		return(-1);
88 
89 	nitems = 0;
90 	while ((d = readdir(dirp)) != NULL) {
91 		if (select != NULL && !(*select)(d))
92 			continue;	/* just selected names */
93 		/*
94 		 * Make a minimum size copy of the data
95 		 */
96 		p = (struct dirent *)malloc(DIRSIZ(d));
97 		if (p == NULL)
98 			return(-1);
99 		p->d_ino = d->d_ino;
100 		p->d_reclen = d->d_reclen;
101 		p->d_namlen = d->d_namlen;
102 		bcopy(d->d_name, p->d_name, p->d_namlen + 1);
103 		/*
104 		 * Check to make sure the array has space left and
105 		 * realloc the maximum size.
106 		 */
107 		if (++nitems >= arraysz) {
108 			if (fstat(dirp->dd_fd, &stb) < 0)
109 				return(-1);	/* just might have grown */
110 			arraysz = stb.st_size / 12;
111 			names = (struct dirent **)realloc((char *)names,
112 				arraysz * sizeof(struct dirent *));
113 			if (names == NULL)
114 				return(-1);
115 		}
116 		names[nitems-1] = p;
117 	}
118 	closedir(dirp);
119 	if (nitems && dcomp != NULL)
120 		qsort(names, nitems, sizeof(struct dirent *), dcomp);
121 	*namelist = names;
122 	return(nitems);
123 }
124 
125 /*
126  * Alphabetic order comparison routine for those who want it.
127  */
128 int
129 alphasort(d1, d2)
130 	const void *d1;
131 	const void *d2;
132 {
133 	return(strcmp((*(struct dirent **)d1)->d_name,
134 	    (*(struct dirent **)d2)->d_name));
135 }
136