1/* 2 Unix SMB/CIFS implementation. 3 4 Copyright (C) Andrew Tridgell 2005 5 Updated for Samba3 64-bit cleanliness (C) Jeremy Allison 2006 6 7 This program is free software; you can redistribute it and/or modify 8 it under the terms of the GNU General Public License as published by 9 the Free Software Foundation; either version 2 of the License, or 10 (at your option) any later version. 11 12 This program is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 GNU General Public License for more details. 16 17 You should have received a copy of the GNU General Public License 18 along with this program; if not, write to the Free Software 19 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 20*/ 21/* 22 a replacement for opendir/readdir/telldir/seekdir/closedir for BSD systems 23 24 This is needed because the existing directory handling in FreeBSD 25 and OpenBSD (and possibly NetBSD) doesn't correctly handle unlink() 26 on files in a directory where telldir() has been used. On a block 27 boundary it will occasionally miss a file when seekdir() is used to 28 return to a position previously recorded with telldir(). 29 30 This also fixes a severe performance and memory usage problem with 31 telldir() on BSD systems. Each call to telldir() in BSD adds an 32 entry to a linked list, and those entries are cleaned up on 33 closedir(). This means with a large directory closedir() can take an 34 arbitrary amount of time, causing network timeouts as millions of 35 telldir() entries are freed 36 37 Note! This replacement code is not portable. It relies on getdents() 38 always leaving the file descriptor at a seek offset that is a 39 multiple of DIR_BUF_SIZE. If the code detects that this doesn't 40 happen then it will abort(). It also does not handle directories 41 with offsets larger than can be stored in a long, 42 43 This code is available under other free software licenses as 44 well. Contact the author. 45*/ 46 47#include <include/includes.h> 48 49 void replace_readdir_dummy(void); 50 void replace_readdir_dummy(void) {} 51 52#if defined(REPLACE_READDIR) 53 54#if defined(PARANOID_MALLOC_CHECKER) 55#ifdef malloc 56#undef malloc 57#endif 58#endif 59 60#define DIR_BUF_BITS 9 61#define DIR_BUF_SIZE (1<<DIR_BUF_BITS) 62 63struct dir_buf { 64 int fd; 65 int nbytes, ofs; 66 SMB_OFF_T seekpos; 67 char buf[DIR_BUF_SIZE]; 68}; 69 70#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_OPENDIR64) 71 SMB_STRUCT_DIR *opendir64(const char *dname) 72#else 73 SMB_STRUCT_DIR *opendir(const char *dname) 74#endif 75{ 76 struct dir_buf *d; 77 d = malloc(sizeof(*d)); 78 if (d == NULL) { 79 errno = ENOMEM; 80 return NULL; 81 } 82#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_OPEN64) 83 d->fd = open64(dname, O_RDONLY); 84#else 85 d->fd = open(dname, O_RDONLY); 86#endif 87 88 if (d->fd == -1) { 89 free(d); 90 return NULL; 91 } 92 d->ofs = 0; 93 d->seekpos = 0; 94 d->nbytes = 0; 95 return (SMB_STRUCT_DIR *)d; 96} 97 98#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_READDIR64) 99 SMB_STRUCT_DIRENT *readdir64(SMB_STRUCT_DIR *dir) 100#else 101 SMB_STRUCT_DIRENT *readdir(SMB_STRUCT_DIR *dir) 102#endif 103{ 104 struct dir_buf *d = (struct dir_buf *)dir; 105 SMB_STRUCT_DIRENT *de; 106 107 if (d->ofs >= d->nbytes) { 108#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_LSEEK64) 109 d->seekpos = lseek64(d->fd, 0, SEEK_CUR); 110#else 111 d->seekpos = lseek(d->fd, 0, SEEK_CUR); 112#endif 113 114#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_GETDENTS64) 115 d->nbytes = getdents64(d->fd, d->buf, DIR_BUF_SIZE); 116#else 117 d->nbytes = getdents(d->fd, d->buf, DIR_BUF_SIZE); 118#endif 119 d->ofs = 0; 120 } 121 if (d->ofs >= d->nbytes) { 122 return NULL; 123 } 124 de = (SMB_STRUCT_DIRENT *)&d->buf[d->ofs]; 125 d->ofs += de->d_reclen; 126 return de; 127} 128 129#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_TELLDIR64) 130 long telldir64(SMB_STRUCT_DIR *dir) 131#else 132 long telldir(SMB_STRUCT_DIR *dir) 133#endif 134{ 135 struct dir_buf *d = (struct dir_buf *)dir; 136 if (d->ofs >= d->nbytes) { 137#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_LSEEK64) 138 d->seekpos = lseek64(d->fd, 0, SEEK_CUR); 139#else 140 d->seekpos = lseek(d->fd, 0, SEEK_CUR); 141#endif 142 d->ofs = 0; 143 d->nbytes = 0; 144 } 145 /* this relies on seekpos always being a multiple of 146 DIR_BUF_SIZE. Is that always true on BSD systems? */ 147 if (d->seekpos & (DIR_BUF_SIZE-1)) { 148 abort(); 149 } 150 return d->seekpos + d->ofs; 151} 152 153#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_SEEKDIR64) 154 void seekdir64(SMB_STRUCT_DIR *dir, long ofs) 155#else 156 void seekdir(SMB_STRUCT_DIR *dir, long ofs) 157#endif 158{ 159 struct dir_buf *d = (struct dir_buf *)dir; 160#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_LSEEK64) 161 d->seekpos = lseek64(d->fd, ofs & ~(DIR_BUF_SIZE-1), SEEK_SET); 162#else 163 d->seekpos = lseek(d->fd, ofs & ~(DIR_BUF_SIZE-1), SEEK_SET); 164#endif 165 166#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_GETDENTS64) 167 d->nbytes = getdents64(d->fd, d->buf, DIR_BUF_SIZE); 168#else 169 d->nbytes = getdents(d->fd, d->buf, DIR_BUF_SIZE); 170#endif 171 172 d->ofs = 0; 173 while (d->ofs < (ofs & (DIR_BUF_SIZE-1))) { 174#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_READDIR64) 175 if (readdir64(dir) == NULL) break; 176#else 177 if (readdir(dir) == NULL) break; 178#endif 179 } 180} 181 182#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_REWINDDIR64) 183 void rewinddir64(SMB_STRUCT_DIR *dir) 184#else 185 void rewinddir(SMB_STRUCT_DIR *dir) 186#endif 187{ 188#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_SEEKDIR64) 189 seekdir64(dir, 0); 190#else 191 seekdir(dir, 0); 192#endif 193} 194 195#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_CLOSEDIR64) 196 int closedir64(SMB_STRUCT_DIR *dir) 197#else 198 int closedir(SMB_STRUCT_DIR *dir) 199#endif 200{ 201 struct dir_buf *d = (struct dir_buf *)dir; 202 int r = close(d->fd); 203 if (r != 0) { 204 return r; 205 } 206 free(d); 207 return 0; 208} 209 210#ifndef dirfd 211/* darn, this is a macro on some systems. */ 212 int dirfd(SMB_STRUCT_DIR *dir) 213{ 214 struct dir_buf *d = (struct dir_buf *)dir; 215 return d->fd; 216} 217#endif 218#endif /* REPLACE_READDIR */ 219