1/* savedir.c -- save the list of files in a directory in a string 2 3 Copyright (C) 1990, 1997, 1998, 1999, 2000, 2001, 2003, 2004, 2005, 4 2006 Free Software Foundation, Inc. 5 6 This program is free software: you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 3 of the License, or 9 (at your option) any later version. 10 11 This program is distributed in the hope that it will be useful, 12 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 GNU General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 18 19/* Written by David MacKenzie <djm@gnu.ai.mit.edu>. */ 20 21#include <config.h> 22 23#include "savedir.h" 24 25#include <sys/types.h> 26 27#include <errno.h> 28 29#include <dirent.h> 30#ifndef _D_EXACT_NAMLEN 31# define _D_EXACT_NAMLEN(dp) strlen ((dp)->d_name) 32#endif 33 34#include <stddef.h> 35#include <stdlib.h> 36#include <string.h> 37 38#include "openat.h" 39#include "xalloc.h" 40 41#ifndef NAME_SIZE_DEFAULT 42# define NAME_SIZE_DEFAULT 512 43#endif 44 45/* The results of opendir() in this file are not used with dirfd and fchdir, 46 therefore save some unnecessary work in fchdir.c. */ 47#undef opendir 48#undef closedir 49 50/* Return a freshly allocated string containing the file names 51 in directory DIRP, separated by '\0' characters; 52 the end is marked by two '\0' characters in a row. 53 Return NULL (setting errno) if DIRP cannot be read or closed. 54 If DIRP is NULL, return NULL without affecting errno. */ 55 56static char * 57savedirstream (DIR *dirp) 58{ 59 char *name_space; 60 size_t allocated = NAME_SIZE_DEFAULT; 61 size_t used = 0; 62 int save_errno; 63 64 if (dirp == NULL) 65 return NULL; 66 67 name_space = xmalloc (allocated); 68 69 for (;;) 70 { 71 struct dirent const *dp; 72 char const *entry; 73 74 errno = 0; 75 dp = readdir (dirp); 76 if (! dp) 77 break; 78 79 /* Skip "", ".", and "..". "" is returned by at least one buggy 80 implementation: Solaris 2.4 readdir on NFS file systems. */ 81 entry = dp->d_name; 82 if (entry[entry[0] != '.' ? 0 : entry[1] != '.' ? 1 : 2] != '\0') 83 { 84 size_t entry_size = _D_EXACT_NAMLEN (dp) + 1; 85 if (used + entry_size < used) 86 xalloc_die (); 87 if (allocated <= used + entry_size) 88 { 89 do 90 { 91 if (2 * allocated < allocated) 92 xalloc_die (); 93 allocated *= 2; 94 } 95 while (allocated <= used + entry_size); 96 97 name_space = xrealloc (name_space, allocated); 98 } 99 memcpy (name_space + used, entry, entry_size); 100 used += entry_size; 101 } 102 } 103 name_space[used] = '\0'; 104 save_errno = errno; 105 if (closedir (dirp) != 0) 106 save_errno = errno; 107 if (save_errno != 0) 108 { 109 free (name_space); 110 errno = save_errno; 111 return NULL; 112 } 113 return name_space; 114} 115 116/* Return a freshly allocated string containing the file names 117 in directory DIR, separated by '\0' characters; 118 the end is marked by two '\0' characters in a row. 119 Return NULL (setting errno) if DIR cannot be opened, read, or closed. */ 120 121char * 122savedir (char const *dir) 123{ 124 return savedirstream (opendir (dir)); 125} 126 127/* Return a freshly allocated string containing the file names 128 in directory FD, separated by '\0' characters; 129 the end is marked by two '\0' characters in a row. 130 Return NULL (setting errno) if FD cannot be read or closed. */ 131 132char * 133fdsavedir (int fd) 134{ 135 return savedirstream (fdopendir (fd)); 136} 137