summaryrefslogtreecommitdiff
path: root/lib/libc/gen/scandir.c
blob: c744b262ce4b19b42c1c8847b4d5c96710a1abc0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
/*
 * Copyright (c) 1983, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char rcsid[] = "$OpenBSD: scandir.c,v 1.3 1997/07/24 00:08:41 deraadt Exp $";
#endif /* LIBC_SCCS and not lint */

/*
 * Scan the directory dirname calling select to make a list of selected
 * directory entries then sort using qsort and compare routine dcomp.
 * Returns the number of entries and a pointer to a list of pointers to
 * struct dirent (through namelist). Returns -1 if there were any errors.
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <dirent.h>
#include <stdlib.h>
#include <string.h>

/*
 * The DIRSIZ macro is the minimum record length which will hold the directory
 * entry.  This requires the amount of space in struct dirent without the
 * d_name field, plus enough space for the name and a terminating nul byte
 * (dp->d_namlen + 1), rounded up to a 4 byte boundary.
 */
#undef DIRSIZ
#define DIRSIZ(dp)							\
	((sizeof(struct dirent) - sizeof(dp)->d_name) +			\
	    (((dp)->d_namlen + 1 + 3) &~ 3))

int
scandir(dirname, namelist, select, dcomp)
	const char *dirname;
	struct dirent ***namelist;
	int (*select) __P((struct dirent *));
	int (*dcomp) __P((const void *, const void *));
{
	register struct dirent *d, *p, **names;
	register size_t nitems;
	struct stat stb;
	long arraysz;
	DIR *dirp;

	if ((dirp = opendir(dirname)) == NULL)
		return(-1);
	if (fstat(dirp->dd_fd, &stb) < 0)
		return(-1);

	/*
	 * estimate the array size by taking the size of the directory file
	 * and dividing it by a multiple of the minimum size entry. 
	 */
	arraysz = (stb.st_size / 24);
	names = (struct dirent **)malloc(arraysz * sizeof(struct dirent *));
	if (names == NULL)
		return(-1);

	nitems = 0;
	while ((d = readdir(dirp)) != NULL) {
		if (select != NULL && !(*select)(d))
			continue;	/* just selected names */
		/*
		 * Make a minimum size copy of the data
		 */
		p = (struct dirent *)malloc(DIRSIZ(d));
		if (p == NULL)
			return(-1);
		p->d_ino = d->d_ino;
		p->d_type = d->d_type;
		p->d_reclen = d->d_reclen;
		p->d_namlen = d->d_namlen;
		bcopy(d->d_name, p->d_name, p->d_namlen + 1);
		/*
		 * Check to make sure the array has space left and
		 * realloc the maximum size.
		 */
		if (++nitems >= arraysz) {
			if (fstat(dirp->dd_fd, &stb) < 0)
				return(-1);	/* just might have grown */
			arraysz = stb.st_size / 12;
			names = (struct dirent **)realloc((char *)names,
				arraysz * sizeof(struct dirent *));
			if (names == NULL)
				return(-1);
		}
		names[nitems-1] = p;
	}
	closedir(dirp);
	if (nitems && dcomp != NULL)
		qsort(names, nitems, sizeof(struct dirent *), dcomp);
	*namelist = names;
	return(nitems);
}

/*
 * Alphabetic order comparison routine for those who want it.
 */
int
alphasort(d1, d2)
	const void *d1;
	const void *d2;
{
	return(strcmp((*(struct dirent **)d1)->d_name,
	    (*(struct dirent **)d2)->d_name));
}