1 /* $NetBSD: scandir.c,v 1.26 2007/06/09 23:57:25 christos Exp $ */ 2 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 #if defined(LIBC_SCCS) && !defined(lint) 34 #if 0 35 static char sccsid[] = "@(#)scandir.c 8.3 (Berkeley) 1/2/94"; 36 #else 37 __RCSID("$NetBSD: scandir.c,v 1.26 2007/06/09 23:57:25 christos Exp $"); 38 #endif 39 #endif /* LIBC_SCCS and not lint */ 40 41 /* 42 * Scan the directory dirname calling selectfn to make a list of selected 43 * directory entries then sort using qsort and compare routine dcomp. 44 * Returns the number of entries and a pointer to a list of pointers to 45 * struct dirent (through namelist). Returns -1 if there were any errors. 46 */ 47 48 #include "namespace.h" 49 #include <sys/types.h> 50 #include <sys/stat.h> 51 52 #include <assert.h> 53 #include <errno.h> 54 #include <dirent.h> 55 #include <stdlib.h> 56 #include <string.h> 57 58 /* 59 * Compute an estimate of the number of entries in a directory based on 60 * the file size. Returns the estimated number of entries or 0 on failure. 61 */ 62 static size_t 63 dirsize(int fd, size_t olen) 64 { 65 struct stat stb; 66 size_t nlen; 67 68 if (fstat(fd, &stb) == -1) 69 return 0; 70 /* 71 * Estimate the array size by taking the size of the directory file 72 * and dividing it by a multiple of the minimum size entry. 73 */ 74 nlen = (size_t)(stb.st_size / _DIRENT_MINSIZE((struct dirent *)0)); 75 /* 76 * If the size turns up 0, switch to an alternate strategy and use the 77 * file size as the number of entries like ZFS returns. If that turns 78 * out to be 0 too return a minimum of 10 entries, plus the old length. 79 */ 80 if (nlen == 0) 81 nlen = (size_t)(stb.st_size ? stb.st_size : 10); 82 return olen + nlen; 83 } 84 85 int 86 scandir(const char *dirname, struct dirent ***namelist, 87 int (*selectfn)(const struct dirent *), 88 int (*dcomp)(const void *, const void *)) 89 { 90 struct dirent *d, *p, **names, **newnames; 91 size_t nitems, arraysz; 92 DIR *dirp; 93 94 _DIAGASSERT(dirname != NULL); 95 _DIAGASSERT(namelist != NULL); 96 97 if ((dirp = opendir(dirname)) == NULL) 98 return -1; 99 100 if ((arraysz = dirsize(dirp->dd_fd, 0)) == 0) 101 goto bad; 102 103 names = malloc(arraysz * sizeof(*names)); 104 if (names == NULL) 105 goto bad; 106 107 nitems = 0; 108 while ((d = readdir(dirp)) != NULL) { 109 if (selectfn != NULL && !(*selectfn)(d)) 110 continue; /* just selected names */ 111 112 /* 113 * Check to make sure the array has space left and 114 * realloc the maximum size. 115 */ 116 if (nitems >= arraysz) { 117 if ((arraysz = dirsize(dirp->dd_fd, arraysz)) == 0) 118 goto bad2; 119 newnames = realloc(names, arraysz * sizeof(*names)); 120 if (newnames == NULL) 121 goto bad2; 122 names = newnames; 123 } 124 125 /* 126 * Make a minimum size copy of the data 127 */ 128 p = malloc((size_t)_DIRENT_SIZE(d)); 129 if (p == NULL) 130 goto bad2; 131 p->d_fileno = d->d_fileno; 132 p->d_reclen = d->d_reclen; 133 p->d_type = d->d_type; 134 p->d_namlen = d->d_namlen; 135 (void)memmove(p->d_name, d->d_name, (size_t)(p->d_namlen + 1)); 136 names[nitems++] = p; 137 } 138 (void)closedir(dirp); 139 if (nitems && dcomp != NULL) 140 qsort(names, nitems, sizeof(*names), dcomp); 141 *namelist = names; 142 return nitems; 143 144 bad2: 145 while (nitems-- > 0) 146 free(names[nitems]); 147 free(names); 148 bad: 149 (void)closedir(dirp); 150 return -1; 151 } 152