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 2, or (at your option) 9 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, write to the Free Software Foundation, 18 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ 19 20/* Written by David MacKenzie <djm@gnu.ai.mit.edu>. */ 21 22#include <config.h> 23 24#include "savedir.h" 25 26#include <sys/types.h> 27 28#include <errno.h> 29 30#include <dirent.h> 31#ifndef _D_EXACT_NAMLEN 32# define _D_EXACT_NAMLEN(dp) strlen ((dp)->d_name) 33#endif 34 35#include <stddef.h> 36#include <stdlib.h> 37#include <string.h> 38 39#include "openat.h" 40#include "xalloc.h" 41 42#ifndef NAME_SIZE_DEFAULT 43# define NAME_SIZE_DEFAULT 512 44#endif 45 46/* The results of opendir() in this file are not used with dirfd and fchdir, 47 therefore save some unnecessary work in fchdir.c. */ 48#undef opendir 49#undef closedir 50 51/* Return a freshly allocated string containing the file names 52 in directory DIRP, separated by '\0' characters; 53 the end is marked by two '\0' characters in a row. 54 Return NULL (setting errno) if DIRP cannot be read or closed. 55 If DIRP is NULL, return NULL without affecting errno. */ 56 57static char * 58savedirstream (DIR *dirp) 59{ 60 char *name_space; 61 size_t allocated = NAME_SIZE_DEFAULT; 62 size_t used = 0; 63 int save_errno; 64 65 if (dirp == NULL) 66 return NULL; 67 68 name_space = xmalloc (allocated); 69 70 for (;;) 71 { 72 struct dirent const *dp; 73 char const *entry; 74 75 errno = 0; 76 dp = readdir (dirp); 77 if (! dp) 78 break; 79 80 /* Skip "", ".", and "..". "" is returned by at least one buggy 81 implementation: Solaris 2.4 readdir on NFS file systems. */ 82 entry = dp->d_name; 83 if (entry[entry[0] != '.' ? 0 : entry[1] != '.' ? 1 : 2] != '\0') 84 { 85 size_t entry_size = _D_EXACT_NAMLEN (dp) + 1; 86 if (used + entry_size < used) 87 xalloc_die (); 88 if (allocated <= used + entry_size) 89 { 90 do 91 { 92 if (2 * allocated < allocated) 93 xalloc_die (); 94 allocated *= 2; 95 } 96 while (allocated <= used + entry_size); 97 98 name_space = xrealloc (name_space, allocated); 99 } 100 memcpy (name_space + used, entry, entry_size); 101 used += entry_size; 102 } 103 } 104 name_space[used] = '\0'; 105 save_errno = errno; 106 if (closedir (dirp) != 0) 107 save_errno = errno; 108 if (save_errno != 0) 109 { 110 free (name_space); 111 errno = save_errno; 112 return NULL; 113 } 114 return name_space; 115} 116 117/* Return a freshly allocated string containing the file names 118 in directory DIR, separated by '\0' characters; 119 the end is marked by two '\0' characters in a row. 120 Return NULL (setting errno) if DIR cannot be opened, read, or closed. */ 121 122char * 123savedir (char const *dir) 124{ 125 return savedirstream (opendir (dir)); 126} 127 128/* Return a freshly allocated string containing the file names 129 in directory FD, separated by '\0' characters; 130 the end is marked by two '\0' characters in a row. 131 Return NULL (setting errno) if FD cannot be read or closed. */ 132 133char * 134fdsavedir (int fd) 135{ 136 return savedirstream (fdopendir (fd)); 137} 138