xref: /freebsd/lib/libc/gen/scandir.c (revision f4b37ed0f8b307b1f3f0f630ca725d68f1dff30d)
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 #ifdef	I_AM_SCANDIR_B
50 #include "block_abi.h"
51 #define	SELECT(x)	CALL_BLOCK(select, x)
52 #ifndef __BLOCKS__
53 void
54 qsort_b(void *, size_t, size_t, void*);
55 #endif
56 #else
57 #define	SELECT(x)	select(x)
58 #endif
59 
60 static int alphasort_thunk(void *thunk, const void *p1, const void *p2);
61 
62 /*
63  * The DIRSIZ macro is the minimum record length which will hold the directory
64  * entry.  This requires the amount of space in struct dirent without the
65  * d_name field, plus enough space for the name and a terminating nul byte
66  * (dp->d_namlen + 1), rounded up to a 4 byte boundary.
67  */
68 #undef DIRSIZ
69 #define DIRSIZ(dp)							\
70 	((sizeof(struct dirent) - sizeof(dp)->d_name) +			\
71 	    (((dp)->d_namlen + 1 + 3) &~ 3))
72 
73 int
74 #ifdef I_AM_SCANDIR_B
75 scandir_b(const char *dirname, struct dirent ***namelist,
76     DECLARE_BLOCK(int, select, const struct dirent *),
77     DECLARE_BLOCK(int, dcomp, const struct dirent **, const struct dirent **))
78 #else
79 scandir(const char *dirname, struct dirent ***namelist,
80     int (*select)(const struct dirent *), int (*dcomp)(const struct dirent **,
81 	const struct dirent **))
82 #endif
83 {
84 	struct dirent *d, *p, **names = NULL;
85 	size_t nitems = 0;
86 	long arraysz;
87 	DIR *dirp;
88 
89 	if ((dirp = opendir(dirname)) == NULL)
90 		return(-1);
91 
92 	arraysz = 32;	/* initial estimate of the array size */
93 	names = (struct dirent **)malloc(arraysz * sizeof(struct dirent *));
94 	if (names == NULL)
95 		goto fail;
96 
97 	while ((d = readdir(dirp)) != NULL) {
98 		if (select != NULL && !SELECT(d))
99 			continue;	/* just selected names */
100 		/*
101 		 * Make a minimum size copy of the data
102 		 */
103 		p = (struct dirent *)malloc(DIRSIZ(d));
104 		if (p == NULL)
105 			goto fail;
106 		p->d_fileno = d->d_fileno;
107 		p->d_type = d->d_type;
108 		p->d_reclen = d->d_reclen;
109 		p->d_namlen = d->d_namlen;
110 		bcopy(d->d_name, p->d_name, p->d_namlen + 1);
111 		/*
112 		 * Check to make sure the array has space left and
113 		 * realloc the maximum size.
114 		 */
115 		if (nitems >= arraysz) {
116 			struct dirent **names2;
117 
118 			names2 = (struct dirent **)realloc((char *)names,
119 				(arraysz * 2) * sizeof(struct dirent *));
120 			if (names2 == NULL) {
121 				free(p);
122 				goto fail;
123 			}
124 			names = names2;
125 			arraysz *= 2;
126 		}
127 		names[nitems++] = p;
128 	}
129 	closedir(dirp);
130 	if (nitems && dcomp != NULL)
131 #ifdef I_AM_SCANDIR_B
132 		qsort_b(names, nitems, sizeof(struct dirent *), (void*)dcomp);
133 #else
134 		qsort_r(names, nitems, sizeof(struct dirent *),
135 		    &dcomp, alphasort_thunk);
136 #endif
137 	*namelist = names;
138 	return (nitems);
139 
140 fail:
141 	while (nitems > 0)
142 		free(names[--nitems]);
143 	free(names);
144 	closedir(dirp);
145 	return (-1);
146 }
147 
148 /*
149  * Alphabetic order comparison routine for those who want it.
150  * POSIX 2008 requires that alphasort() uses strcoll().
151  */
152 int
153 alphasort(const struct dirent **d1, const struct dirent **d2)
154 {
155 
156 	return (strcoll((*d1)->d_name, (*d2)->d_name));
157 }
158 
159 static int
160 alphasort_thunk(void *thunk, const void *p1, const void *p2)
161 {
162 	int (*dc)(const struct dirent **, const struct dirent **);
163 
164 	dc = *(int (**)(const struct dirent **, const struct dirent **))thunk;
165 	return (dc((const struct dirent **)p1, (const struct dirent **)p2));
166 }
167