xref: /freebsd/lib/libc/gen/scandir.c (revision dd41de95a84d979615a2ef11df6850622bf6184e)
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 #ifdef I_AM_SCANDIR_B
60 typedef DECLARE_BLOCK(int, select_block, const struct dirent *);
61 typedef DECLARE_BLOCK(int, dcomp_block, const struct dirent **,
62     const struct dirent **);
63 #else
64 static int alphasort_thunk(void *thunk, const void *p1, const void *p2);
65 #endif
66 
67 int
68 #ifdef I_AM_SCANDIR_B
69 scandir_b(const char *dirname, struct dirent ***namelist, select_block select,
70     dcomp_block dcomp)
71 #else
72 scandir(const char *dirname, struct dirent ***namelist,
73     int (*select)(const struct dirent *), int (*dcomp)(const struct dirent **,
74 	const struct dirent **))
75 #endif
76 {
77 	struct dirent *d, *p, **names = NULL;
78 	size_t arraysz, numitems;
79 	DIR *dirp;
80 
81 	if ((dirp = opendir(dirname)) == NULL)
82 		return(-1);
83 
84 	numitems = 0;
85 	arraysz = 32;	/* initial estimate of the array size */
86 	names = (struct dirent **)malloc(arraysz * sizeof(struct dirent *));
87 	if (names == NULL)
88 		goto fail;
89 
90 	while ((d = readdir(dirp)) != NULL) {
91 		if (select != NULL && !SELECT(d))
92 			continue;	/* just selected names */
93 		/*
94 		 * Make a minimum size copy of the data
95 		 */
96 		p = (struct dirent *)malloc(_GENERIC_DIRSIZ(d));
97 		if (p == NULL)
98 			goto fail;
99 		p->d_fileno = d->d_fileno;
100 		p->d_type = d->d_type;
101 		p->d_reclen = d->d_reclen;
102 		p->d_namlen = d->d_namlen;
103 		bcopy(d->d_name, p->d_name, p->d_namlen + 1);
104 		/*
105 		 * Check to make sure the array has space left and
106 		 * realloc the maximum size.
107 		 */
108 		if (numitems >= arraysz) {
109 			struct dirent **names2;
110 
111 			names2 = reallocarray(names, arraysz,
112 			    2 * sizeof(struct dirent *));
113 			if (names2 == NULL) {
114 				free(p);
115 				goto fail;
116 			}
117 			names = names2;
118 			arraysz *= 2;
119 		}
120 		names[numitems++] = p;
121 	}
122 	closedir(dirp);
123 	if (numitems && dcomp != NULL)
124 #ifdef I_AM_SCANDIR_B
125 		qsort_b(names, numitems, sizeof(struct dirent *), (void*)dcomp);
126 #else
127 		qsort_r(names, numitems, sizeof(struct dirent *),
128 		    &dcomp, alphasort_thunk);
129 #endif
130 	*namelist = names;
131 	return (numitems);
132 
133 fail:
134 	while (numitems > 0)
135 		free(names[--numitems]);
136 	free(names);
137 	closedir(dirp);
138 	return (-1);
139 }
140 
141 #ifndef I_AM_SCANDIR_B
142 /*
143  * Alphabetic order comparison routine for those who want it.
144  * POSIX 2008 requires that alphasort() uses strcoll().
145  */
146 int
147 alphasort(const struct dirent **d1, const struct dirent **d2)
148 {
149 
150 	return (strcoll((*d1)->d_name, (*d2)->d_name));
151 }
152 
153 static int
154 alphasort_thunk(void *thunk, const void *p1, const void *p2)
155 {
156 	int (*dc)(const struct dirent **, const struct dirent **);
157 
158 	dc = *(int (**)(const struct dirent **, const struct dirent **))thunk;
159 	return (dc((const struct dirent **)p1, (const struct dirent **)p2));
160 }
161 #endif
162