xref: /freebsd/lib/libc/gen/scandir.c (revision d8a0fe102c0cfdfcd5b818f850eff09d8536c9bc)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1983, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #if defined(LIBC_SCCS) && !defined(lint)
33 static char sccsid[] = "@(#)scandir.c	8.3 (Berkeley) 1/2/94";
34 #endif /* LIBC_SCCS and not lint */
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
37 
38 /*
39  * Scan the directory dirname calling select to make a list of selected
40  * directory entries then sort using qsort and compare routine dcomp.
41  * Returns the number of entries and a pointer to a list of pointers to
42  * struct dirent (through namelist). Returns -1 if there were any errors.
43  */
44 
45 #include "namespace.h"
46 #include <dirent.h>
47 #include <stdlib.h>
48 #include <string.h>
49 #include "un-namespace.h"
50 
51 #ifdef	I_AM_SCANDIR_B
52 #include "block_abi.h"
53 #define	SELECT(x)	CALL_BLOCK(select, x)
54 #ifndef __BLOCKS__
55 void
56 qsort_b(void *, size_t, size_t, void*);
57 #endif
58 #else
59 #define	SELECT(x)	select(x)
60 #endif
61 
62 static int alphasort_thunk(void *thunk, const void *p1, const void *p2);
63 
64 int
65 #ifdef I_AM_SCANDIR_B
66 scandir_b(const char *dirname, struct dirent ***namelist,
67     DECLARE_BLOCK(int, select, const struct dirent *),
68     DECLARE_BLOCK(int, dcomp, const struct dirent **, const struct dirent **))
69 #else
70 scandir(const char *dirname, struct dirent ***namelist,
71     int (*select)(const struct dirent *), int (*dcomp)(const struct dirent **,
72 	const struct dirent **))
73 #endif
74 {
75 	struct dirent *d, *p, **names = NULL;
76 	size_t arraysz, numitems;
77 	DIR *dirp;
78 
79 	if ((dirp = opendir(dirname)) == NULL)
80 		return(-1);
81 
82 	numitems = 0;
83 	arraysz = 32;	/* initial estimate of the array size */
84 	names = (struct dirent **)malloc(arraysz * sizeof(struct dirent *));
85 	if (names == NULL)
86 		goto fail;
87 
88 	while ((d = readdir(dirp)) != NULL) {
89 		if (select != NULL && !SELECT(d))
90 			continue;	/* just selected names */
91 		/*
92 		 * Make a minimum size copy of the data
93 		 */
94 		p = (struct dirent *)malloc(_GENERIC_DIRSIZ(d));
95 		if (p == NULL)
96 			goto fail;
97 		p->d_fileno = d->d_fileno;
98 		p->d_type = d->d_type;
99 		p->d_reclen = d->d_reclen;
100 		p->d_namlen = d->d_namlen;
101 		bcopy(d->d_name, p->d_name, p->d_namlen + 1);
102 		/*
103 		 * Check to make sure the array has space left and
104 		 * realloc the maximum size.
105 		 */
106 		if (numitems >= arraysz) {
107 			struct dirent **names2;
108 
109 			names2 = reallocarray(names, arraysz,
110 			    2 * sizeof(struct dirent *));
111 			if (names2 == NULL) {
112 				free(p);
113 				goto fail;
114 			}
115 			names = names2;
116 			arraysz *= 2;
117 		}
118 		names[numitems++] = p;
119 	}
120 	closedir(dirp);
121 	if (numitems && dcomp != NULL)
122 #ifdef I_AM_SCANDIR_B
123 		qsort_b(names, numitems, sizeof(struct dirent *), (void*)dcomp);
124 #else
125 		qsort_r(names, numitems, sizeof(struct dirent *),
126 		    &dcomp, alphasort_thunk);
127 #endif
128 	*namelist = names;
129 	return (numitems);
130 
131 fail:
132 	while (numitems > 0)
133 		free(names[--numitems]);
134 	free(names);
135 	closedir(dirp);
136 	return (-1);
137 }
138 
139 /*
140  * Alphabetic order comparison routine for those who want it.
141  * POSIX 2008 requires that alphasort() uses strcoll().
142  */
143 int
144 alphasort(const struct dirent **d1, const struct dirent **d2)
145 {
146 
147 	return (strcoll((*d1)->d_name, (*d2)->d_name));
148 }
149 
150 static int
151 alphasort_thunk(void *thunk, const void *p1, const void *p2)
152 {
153 	int (*dc)(const struct dirent **, const struct dirent **);
154 
155 	dc = *(int (**)(const struct dirent **, const struct dirent **))thunk;
156 	return (dc((const struct dirent **)p1, (const struct dirent **)p2));
157 }
158