scandir.c revision 1.22.6.1
1 /* $NetBSD: scandir.c,v 1.22.6.1 2007/06/12 16:16:20 liamjfoy 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 1.22.6.1 2007/06/12 16:16:20 liamjfoy Exp $"); 38 #endif 39 #endif /* LIBC_SCCS and not lint */ 40 41 /* 42 * Scan the directory dirname calling select 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 #ifdef __weak_alias 59 __weak_alias(scandir,_scandir) 60 __weak_alias(alphasort,_alphasort) 61 #endif 62 63 64 /* 65 * Compute an estimate of the number of entries in a directory based on 66 * the file size. Returns the estimated number of entries or 0 on failure. 67 */ 68 static size_t 69 dirsize(int fd, size_t olen) 70 { 71 struct stat stb; 72 size_t nlen; 73 74 if (fstat(fd, &stb) == -1) 75 return 0; 76 /* 77 * Estimate the array size by taking the size of the directory file 78 * and dividing it by a multiple of the minimum size entry. 79 */ 80 nlen = (size_t)(stb.st_size / 24 /*_DIRENT_MINSIZE((struct dirent *)0)*/ ); 81 /* 82 * If the size turns up 0, switch to an alternate strategy and use the 83 * file size as the number of entries like ZFS returns. If that turns 84 * out to be 0 too return a minimum of 10 entries, plus the old length. 85 */ 86 if (nlen == 0) 87 nlen = (size_t)(stb.st_size ? stb.st_size : 10); 88 return olen + nlen; 89 } 90 91 /* 92 * The DIRSIZ macro is the minimum record length which will hold the directory 93 * entry. This requires the amount of space in struct dirent without the 94 * d_name field, plus enough space for the name and a terminating nul byte 95 * (dp->d_namlen + 1), rounded up to a 4 byte boundary. 96 */ 97 #undef DIRSIZ 98 #define DIRSIZ(dp) \ 99 ((sizeof(struct dirent) - sizeof(dp)->d_name) + \ 100 (((dp)->d_namlen + 1 + 3) &~ 3)) 101 102 int 103 scandir(dirname, namelist, select, dcomp) 104 const char *dirname; 105 struct dirent ***namelist; 106 int (*select) __P((const struct dirent *)); 107 int (*dcomp) __P((const void *, const void *)); 108 { 109 struct dirent *d, *p, **names, **newnames; 110 size_t nitems, arraysz; 111 DIR *dirp; 112 113 _DIAGASSERT(dirname != NULL); 114 _DIAGASSERT(namelist != NULL); 115 116 if ((dirp = opendir(dirname)) == NULL) 117 return (-1); 118 119 if ((arraysz = dirsize(dirp->dd_fd, 0)) == 0) 120 goto bad; 121 122 names = malloc(arraysz * sizeof(struct dirent *)); 123 if (names == NULL) 124 goto bad; 125 126 nitems = 0; 127 while ((d = readdir(dirp)) != NULL) { 128 if (select != NULL && !(*select)(d)) 129 continue; /* just selected names */ 130 131 /* 132 * Check to make sure the array has space left and 133 * realloc the maximum size. 134 */ 135 if (nitems >= arraysz) { 136 if ((arraysz = dirsize(dirp->dd_fd, arraysz)) == 0) 137 goto bad2; 138 newnames = realloc(names, 139 arraysz * sizeof(struct dirent *)); 140 if (newnames == NULL) 141 goto bad2; 142 names = newnames; 143 } 144 145 /* 146 * Make a minimum size copy of the data 147 */ 148 p = (struct dirent *)malloc(DIRSIZ(d)); 149 if (p == NULL) 150 goto bad2; 151 p->d_fileno = d->d_fileno; 152 p->d_reclen = d->d_reclen; 153 p->d_type = d->d_type; 154 p->d_namlen = d->d_namlen; 155 memmove(p->d_name, d->d_name, (size_t)(p->d_namlen + 1)); 156 names[nitems++] = p; 157 } 158 closedir(dirp); 159 if (nitems && dcomp != NULL) 160 qsort(names, nitems, sizeof(struct dirent *), dcomp); 161 *namelist = names; 162 return (nitems); 163 164 bad2: 165 while (nitems-- > 0) 166 free(names[nitems]); 167 free(names); 168 bad: 169 closedir(dirp); 170 return (-1); 171 } 172 173 /* 174 * Alphabetic order comparison routine for those who want it. 175 */ 176 int 177 alphasort(d1, d2) 178 const void *d1; 179 const void *d2; 180 { 181 182 _DIAGASSERT(d1 != NULL); 183 _DIAGASSERT(d2 != NULL); 184 185 return (strcmp((*(const struct dirent *const *)d1)->d_name, 186 (*(const struct dirent *const *)d2)->d_name)); 187 } 188
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