xref: /freebsd/lib/libc/gen/scandir.c (revision ca987d4641cdcd7f27e153db17c5bf064934faf5)
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. 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 int
63 #ifdef I_AM_SCANDIR_B
64 scandir_b(const char *dirname, struct dirent ***namelist,
65     DECLARE_BLOCK(int, select, const struct dirent *),
66     DECLARE_BLOCK(int, dcomp, const struct dirent **, const struct dirent **))
67 #else
68 scandir(const char *dirname, struct dirent ***namelist,
69     int (*select)(const struct dirent *), int (*dcomp)(const struct dirent **,
70 	const struct dirent **))
71 #endif
72 {
73 	struct dirent *d, *p, **names = NULL;
74 	size_t arraysz, numitems;
75 	DIR *dirp;
76 
77 	if ((dirp = opendir(dirname)) == NULL)
78 		return(-1);
79 
80 	numitems = 0;
81 	arraysz = 32;	/* initial estimate of the array size */
82 	names = (struct dirent **)malloc(arraysz * sizeof(struct dirent *));
83 	if (names == NULL)
84 		goto fail;
85 
86 	while ((d = readdir(dirp)) != NULL) {
87 		if (select != NULL && !SELECT(d))
88 			continue;	/* just selected names */
89 		/*
90 		 * Make a minimum size copy of the data
91 		 */
92 		p = (struct dirent *)malloc(_GENERIC_DIRSIZ(d));
93 		if (p == NULL)
94 			goto fail;
95 		p->d_fileno = d->d_fileno;
96 		p->d_type = d->d_type;
97 		p->d_reclen = d->d_reclen;
98 		p->d_namlen = d->d_namlen;
99 		bcopy(d->d_name, p->d_name, p->d_namlen + 1);
100 		/*
101 		 * Check to make sure the array has space left and
102 		 * realloc the maximum size.
103 		 */
104 		if (numitems >= arraysz) {
105 			struct dirent **names2;
106 
107 			names2 = reallocarray(names, arraysz,
108 			    2 * sizeof(struct dirent *));
109 			if (names2 == NULL) {
110 				free(p);
111 				goto fail;
112 			}
113 			names = names2;
114 			arraysz *= 2;
115 		}
116 		names[numitems++] = p;
117 	}
118 	closedir(dirp);
119 	if (numitems && dcomp != NULL)
120 #ifdef I_AM_SCANDIR_B
121 		qsort_b(names, numitems, sizeof(struct dirent *), (void*)dcomp);
122 #else
123 		qsort_r(names, numitems, sizeof(struct dirent *),
124 		    &dcomp, alphasort_thunk);
125 #endif
126 	*namelist = names;
127 	return (numitems);
128 
129 fail:
130 	while (numitems > 0)
131 		free(names[--numitems]);
132 	free(names);
133 	closedir(dirp);
134 	return (-1);
135 }
136 
137 /*
138  * Alphabetic order comparison routine for those who want it.
139  * POSIX 2008 requires that alphasort() uses strcoll().
140  */
141 int
142 alphasort(const struct dirent **d1, const struct dirent **d2)
143 {
144 
145 	return (strcoll((*d1)->d_name, (*d2)->d_name));
146 }
147 
148 static int
149 alphasort_thunk(void *thunk, const void *p1, const void *p2)
150 {
151 	int (*dc)(const struct dirent **, const struct dirent **);
152 
153 	dc = *(int (**)(const struct dirent **, const struct dirent **))thunk;
154 	return (dc((const struct dirent **)p1, (const struct dirent **)p2));
155 }
156