xref: /freebsd/lib/libc/gen/scandir.c (revision cc321ccd)
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 static int alphasort_thunk(void *thunk, const void *p1, const void *p2);
60 
61 int
62 #ifdef I_AM_SCANDIR_B
63 scandir_b(const char *dirname, struct dirent ***namelist,
64     DECLARE_BLOCK(int, select, const struct dirent *),
65     DECLARE_BLOCK(int, dcomp, const struct dirent **, const struct dirent **))
66 #else
67 scandir(const char *dirname, struct dirent ***namelist,
68     int (*select)(const struct dirent *), int (*dcomp)(const struct dirent **,
69 	const struct dirent **))
70 #endif
71 {
72 	struct dirent *d, *p, **names = NULL;
73 	size_t arraysz, numitems;
74 	DIR *dirp;
75 
76 	if ((dirp = opendir(dirname)) == NULL)
77 		return(-1);
78 
79 	numitems = 0;
80 	arraysz = 32;	/* initial estimate of the array size */
81 	names = (struct dirent **)malloc(arraysz * sizeof(struct dirent *));
82 	if (names == NULL)
83 		goto fail;
84 
85 	while ((d = readdir(dirp)) != NULL) {
86 		if (select != NULL && !SELECT(d))
87 			continue;	/* just selected names */
88 		/*
89 		 * Make a minimum size copy of the data
90 		 */
91 		p = (struct dirent *)malloc(_GENERIC_DIRSIZ(d));
92 		if (p == NULL)
93 			goto fail;
94 		p->d_fileno = d->d_fileno;
95 		p->d_type = d->d_type;
96 		p->d_reclen = d->d_reclen;
97 		p->d_namlen = d->d_namlen;
98 		bcopy(d->d_name, p->d_name, p->d_namlen + 1);
99 		/*
100 		 * Check to make sure the array has space left and
101 		 * realloc the maximum size.
102 		 */
103 		if (numitems >= arraysz) {
104 			struct dirent **names2;
105 
106 			names2 = reallocarray(names, arraysz,
107 			    2 * sizeof(struct dirent *));
108 			if (names2 == NULL) {
109 				free(p);
110 				goto fail;
111 			}
112 			names = names2;
113 			arraysz *= 2;
114 		}
115 		names[numitems++] = p;
116 	}
117 	closedir(dirp);
118 	if (numitems && dcomp != NULL)
119 #ifdef I_AM_SCANDIR_B
120 		qsort_b(names, numitems, sizeof(struct dirent *), (void*)dcomp);
121 #else
122 		qsort_r(names, numitems, sizeof(struct dirent *),
123 		    &dcomp, alphasort_thunk);
124 #endif
125 	*namelist = names;
126 	return (numitems);
127 
128 fail:
129 	while (numitems > 0)
130 		free(names[--numitems]);
131 	free(names);
132 	closedir(dirp);
133 	return (-1);
134 }
135 
136 #ifndef I_AM_SCANDIR_B
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 #endif
157