1 /* $OpenBSD: scandir.c,v 1.12 2007/09/02 15:19:16 deraadt Exp $ */ 2 /* 3 * Copyright (c) 1983, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. Neither the name of the University nor the names of its contributors 15 * may be used to endorse or promote products derived from this software 16 * without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 */ 30 31 /* 32 * Scan the directory dirname calling select to make a list of selected 33 * directory entries then sort using qsort and compare routine dcomp. 34 * Returns the number of entries and a pointer to a list of pointers to 35 * struct dirent (through namelist). Returns -1 if there were any errors. 36 */ 37 38 #include <sys/param.h> 39 #include <sys/stat.h> 40 #include <dirent.h> 41 #include <errno.h> 42 #include <limits.h> 43 #include <stdlib.h> 44 #include <string.h> 45 46 /* 47 * The DIRSIZ macro is the minimum record length which will hold the directory 48 * entry. This requires the amount of space in struct dirent without the 49 * d_name field, plus enough space for the name and a terminating nul byte 50 * (dp->d_namlen + 1), rounded up to a 4 byte boundary. 51 */ 52 #undef DIRSIZ 53 #define DIRSIZ(dp) \ 54 ((sizeof(struct dirent) - sizeof(dp)->d_name) + \ 55 (((dp)->d_namlen + 1 + 3) &~ 3)) 56 57 int 58 scandir(const char *dirname, struct dirent ***namelist, 59 int (*select)(struct dirent *), int (*dcomp)(const void *, const void *)) 60 { 61 struct dirent *d, *p, **names = NULL; 62 size_t nitems = 0; 63 struct stat stb; 64 long arraysz; 65 DIR *dirp; 66 67 if ((dirp = opendir(dirname)) == NULL) 68 return (-1); 69 if (fstat(dirp->dd_fd, &stb) < 0) 70 goto fail; 71 72 /* 73 * estimate the array size by taking the size of the directory file 74 * and dividing it by a multiple of the minimum size entry. 75 */ 76 arraysz = MAX(stb.st_size / 24, 16); 77 if (arraysz > SIZE_MAX / sizeof(struct dirent *)) { 78 errno = ENOMEM; 79 goto fail; 80 } 81 names = (struct dirent **)calloc(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 /* 90 * Check to make sure the array has space left and 91 * realloc the maximum size. 92 */ 93 if (nitems >= arraysz) { 94 struct dirent **nnames; 95 96 if (fstat(dirp->dd_fd, &stb) < 0) 97 goto fail; 98 99 arraysz *= 2; 100 if (SIZE_MAX / sizeof(struct dirent *) < arraysz) 101 goto fail; 102 nnames = (struct dirent **)realloc((char *)names, 103 arraysz * sizeof(struct dirent *)); 104 if (nnames == NULL) 105 goto fail; 106 107 names = nnames; 108 } 109 110 /* 111 * Make a minimum size copy of the data 112 */ 113 p = (struct dirent *)malloc(DIRSIZ(d)); 114 if (p == NULL) 115 goto fail; 116 117 p->d_ino = d->d_ino; 118 p->d_type = d->d_type; 119 p->d_reclen = d->d_reclen; 120 p->d_namlen = d->d_namlen; 121 bcopy(d->d_name, p->d_name, p->d_namlen + 1); 122 names[nitems++] = p; 123 } 124 closedir(dirp); 125 if (nitems && dcomp != NULL) 126 qsort(names, nitems, sizeof(struct dirent *), dcomp); 127 *namelist = names; 128 return (nitems); 129 130 fail: 131 while (nitems > 0) 132 free(names[--nitems]); 133 free(names); 134 closedir(dirp); 135 return (-1); 136 } 137 138 /* 139 * Alphabetic order comparison routine for those who want it. 140 */ 141 int 142 alphasort(const void *d1, const void *d2) 143 { 144 return(strcmp((*(struct dirent **)d1)->d_name, 145 (*(struct dirent **)d2)->d_name)); 146 } 147