1/* vi: set sw=4 ts=4: */ 2/* 3 * dir_iterate.c --- ext2fs directory iteration operations 4 * 5 * Copyright (C) 1993, 1994, 1994, 1995, 1996, 1997 Theodore Ts'o. 6 * 7 * %Begin-Header% 8 * This file may be redistributed under the terms of the GNU Public 9 * License. 10 * %End-Header% 11 */ 12 13#include <stdio.h> 14#include <string.h> 15#if HAVE_UNISTD_H 16#include <unistd.h> 17#endif 18#if HAVE_ERRNO_H 19#include <errno.h> 20#endif 21 22#include "ext2_fs.h" 23#include "ext2fsP.h" 24 25/* 26 * This function checks to see whether or not a potential deleted 27 * directory entry looks valid. What we do is check the deleted entry 28 * and each successive entry to make sure that they all look valid and 29 * that the last deleted entry ends at the beginning of the next 30 * undeleted entry. Returns 1 if the deleted entry looks valid, zero 31 * if not valid. 32 */ 33static int ext2fs_validate_entry(char *buf, int offset, int final_offset) 34{ 35 struct ext2_dir_entry *dirent; 36 37 while (offset < final_offset) { 38 dirent = (struct ext2_dir_entry *)(buf + offset); 39 offset += dirent->rec_len; 40 if ((dirent->rec_len < 8) || 41 ((dirent->rec_len % 4) != 0) || 42 (((dirent->name_len & 0xFF)+8) > dirent->rec_len)) 43 return 0; 44 } 45 return (offset == final_offset); 46} 47 48errcode_t ext2fs_dir_iterate2(ext2_filsys fs, 49 ext2_ino_t dir, 50 int flags, 51 char *block_buf, 52 int (*func)(ext2_ino_t dir, 53 int entry, 54 struct ext2_dir_entry *dirent, 55 int offset, 56 int blocksize, 57 char *buf, 58 void *priv_data), 59 void *priv_data) 60{ 61 struct dir_context ctx; 62 errcode_t retval; 63 64 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); 65 66 retval = ext2fs_check_directory(fs, dir); 67 if (retval) 68 return retval; 69 70 ctx.dir = dir; 71 ctx.flags = flags; 72 if (block_buf) 73 ctx.buf = block_buf; 74 else { 75 retval = ext2fs_get_mem(fs->blocksize, &ctx.buf); 76 if (retval) 77 return retval; 78 } 79 ctx.func = func; 80 ctx.priv_data = priv_data; 81 ctx.errcode = 0; 82 retval = ext2fs_block_iterate2(fs, dir, 0, 0, 83 ext2fs_process_dir_block, &ctx); 84 if (!block_buf) 85 ext2fs_free_mem(&ctx.buf); 86 if (retval) 87 return retval; 88 return ctx.errcode; 89} 90 91struct xlate { 92 int (*func)(struct ext2_dir_entry *dirent, 93 int offset, 94 int blocksize, 95 char *buf, 96 void *priv_data); 97 void *real_private; 98}; 99 100static int xlate_func(ext2_ino_t dir EXT2FS_ATTR((unused)), 101 int entry EXT2FS_ATTR((unused)), 102 struct ext2_dir_entry *dirent, int offset, 103 int blocksize, char *buf, void *priv_data) 104{ 105 struct xlate *xl = (struct xlate *) priv_data; 106 107 return (*xl->func)(dirent, offset, blocksize, buf, xl->real_private); 108} 109 110extern errcode_t ext2fs_dir_iterate(ext2_filsys fs, 111 ext2_ino_t dir, 112 int flags, 113 char *block_buf, 114 int (*func)(struct ext2_dir_entry *dirent, 115 int offset, 116 int blocksize, 117 char *buf, 118 void *priv_data), 119 void *priv_data) 120{ 121 struct xlate xl; 122 123 xl.real_private = priv_data; 124 xl.func = func; 125 126 return ext2fs_dir_iterate2(fs, dir, flags, block_buf, 127 xlate_func, &xl); 128} 129 130 131/* 132 * Helper function which is private to this module. Used by 133 * ext2fs_dir_iterate() and ext2fs_dblist_dir_iterate() 134 */ 135int ext2fs_process_dir_block(ext2_filsys fs, 136 blk_t *blocknr, 137 e2_blkcnt_t blockcnt, 138 blk_t ref_block EXT2FS_ATTR((unused)), 139 int ref_offset EXT2FS_ATTR((unused)), 140 void *priv_data) 141{ 142 struct dir_context *ctx = (struct dir_context *) priv_data; 143 unsigned int offset = 0; 144 unsigned int next_real_entry = 0; 145 int ret = 0; 146 int changed = 0; 147 int do_abort = 0; 148 int entry, size; 149 struct ext2_dir_entry *dirent; 150 151 if (blockcnt < 0) 152 return 0; 153 154 entry = blockcnt ? DIRENT_OTHER_FILE : DIRENT_DOT_FILE; 155 156 ctx->errcode = ext2fs_read_dir_block(fs, *blocknr, ctx->buf); 157 if (ctx->errcode) 158 return BLOCK_ABORT; 159 160 while (offset < fs->blocksize) { 161 dirent = (struct ext2_dir_entry *) (ctx->buf + offset); 162 if (((offset + dirent->rec_len) > fs->blocksize) || 163 (dirent->rec_len < 8) || 164 ((dirent->rec_len % 4) != 0) || 165 (((dirent->name_len & 0xFF)+8) > dirent->rec_len)) { 166 ctx->errcode = EXT2_ET_DIR_CORRUPTED; 167 return BLOCK_ABORT; 168 } 169 if (!dirent->inode && 170 !(ctx->flags & DIRENT_FLAG_INCLUDE_EMPTY)) 171 goto next; 172 173 ret = (ctx->func)(ctx->dir, 174 (next_real_entry > offset) ? 175 DIRENT_DELETED_FILE : entry, 176 dirent, offset, 177 fs->blocksize, ctx->buf, 178 ctx->priv_data); 179 if (entry < DIRENT_OTHER_FILE) 180 entry++; 181 182 if (ret & DIRENT_CHANGED) 183 changed++; 184 if (ret & DIRENT_ABORT) { 185 do_abort++; 186 break; 187 } 188next: 189 if (next_real_entry == offset) 190 next_real_entry += dirent->rec_len; 191 192 if (ctx->flags & DIRENT_FLAG_INCLUDE_REMOVED) { 193 size = ((dirent->name_len & 0xFF) + 11) & ~3; 194 195 if (dirent->rec_len != size) { 196 unsigned int final_offset; 197 198 final_offset = offset + dirent->rec_len; 199 offset += size; 200 while (offset < final_offset && 201 !ext2fs_validate_entry(ctx->buf, 202 offset, 203 final_offset)) 204 offset += 4; 205 continue; 206 } 207 } 208 offset += dirent->rec_len; 209 } 210 211 if (changed) { 212 ctx->errcode = ext2fs_write_dir_block(fs, *blocknr, ctx->buf); 213 if (ctx->errcode) 214 return BLOCK_ABORT; 215 } 216 if (do_abort) 217 return BLOCK_ABORT; 218 return 0; 219} 220