xref: /freebsd/lib/libc/gen/scandir.c (revision da477bcdc0c335171bb0ed3813f570026de6df85)
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 #include <sys/cdefs.h>
33 __SCCSID("@(#)scandir.c	8.3 (Berkeley) 1/2/94");
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 qsort_b(void *, size_t, size_t, void *);
54 #endif
55 #else
56 #define	SELECT(x)	select(x)
57 #endif
58 
59 #ifndef I_AM_SCANDIR_B
60 static int alphasort_thunk(void *thunk, const void *p1, const void *p2);
61 #endif
62 
63 int
64 #ifdef I_AM_SCANDIR_B
65 scandir_b(const char *dirname, struct dirent ***namelist,
66     DECLARE_BLOCK(int, select, const struct dirent *),
67     DECLARE_BLOCK(int, dcomp, const struct dirent **, const struct dirent **))
68 #else
69 scandir(const char *dirname, struct dirent ***namelist,
70     int (*select)(const struct dirent *), int (*dcomp)(const struct dirent **,
71 	const struct dirent **))
72 #endif
73 {
74 	struct dirent *d, *p, **names = NULL;
75 	size_t arraysz, numitems;
76 	DIR *dirp;
77 
78 	if ((dirp = opendir(dirname)) == NULL)
79 		return(-1);
80 
81 	numitems = 0;
82 	arraysz = 32;	/* initial estimate of the array size */
83 	names = (struct dirent **)malloc(arraysz * sizeof(struct dirent *));
84 	if (names == NULL)
85 		goto fail;
86 
87 	while ((d = readdir(dirp)) != NULL) {
88 		if (select != NULL && !SELECT(d))
89 			continue;	/* just selected names */
90 		/*
91 		 * Make a minimum size copy of the data
92 		 */
93 		p = (struct dirent *)malloc(_GENERIC_DIRSIZ(d));
94 		if (p == NULL)
95 			goto fail;
96 		p->d_fileno = d->d_fileno;
97 		p->d_type = d->d_type;
98 		p->d_reclen = d->d_reclen;
99 		p->d_namlen = d->d_namlen;
100 		bcopy(d->d_name, p->d_name, p->d_namlen + 1);
101 		/*
102 		 * Check to make sure the array has space left and
103 		 * realloc the maximum size.
104 		 */
105 		if (numitems >= arraysz) {
106 			struct dirent **names2;
107 
108 			names2 = reallocarray(names, arraysz,
109 			    2 * sizeof(struct dirent *));
110 			if (names2 == NULL) {
111 				free(p);
112 				goto fail;
113 			}
114 			names = names2;
115 			arraysz *= 2;
116 		}
117 		names[numitems++] = p;
118 	}
119 	closedir(dirp);
120 	if (numitems && dcomp != NULL)
121 #ifdef I_AM_SCANDIR_B
122 		qsort_b(names, numitems, sizeof(struct dirent *), (void*)dcomp);
123 #else
124 		qsort_r(names, numitems, sizeof(struct dirent *),
125 		    &dcomp, alphasort_thunk);
126 #endif
127 	*namelist = names;
128 	return (numitems);
129 
130 fail:
131 	while (numitems > 0)
132 		free(names[--numitems]);
133 	free(names);
134 	closedir(dirp);
135 	return (-1);
136 }
137 
138 #ifndef I_AM_SCANDIR_B
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 #endif
159