/* *(C) Copyright 2004 * esd gmbh * Reinhard Arlt * * based on code from grub2 fs/ext2.c and fs/fshelp.c by * * GRUB -- GRand Unified Bootloader * Copyright(C) 2003, 2004 Free Software Foundation, Inc. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include #include #include #include extern int ext2fs_devread(int sector, int byte_offset, int byte_len, char *buf); /* Magic value used to identify an ext2 filesystem. */ #define EXT2_MAGIC 0xEF53 /* Amount of indirect blocks in an inode. */ #define INDIRECT_BLOCKS 12 /* Maximum lenght of a pathname. */ #define EXT2_PATH_MAX 4096 /* Maximum nesting of symlinks, used to prevent a loop. */ #define EXT2_MAX_SYMLINKCNT 8 /* Filetype used in directory entry. */ #define FILETYPE_UNKNOWN 0 #define FILETYPE_REG 1 #define FILETYPE_DIRECTORY 2 #define FILETYPE_SYMLINK 7 /* Filetype information as used in inodes. */ #define FILETYPE_INO_MASK 0170000 #define FILETYPE_INO_REG 0100000 #define FILETYPE_INO_DIRECTORY 0040000 #define FILETYPE_INO_SYMLINK 0120000 /* Bits used as offset in sector */ #define DISK_SECTOR_BITS 9 /* Log2 size of ext2 block in 512 blocks. */ #define LOG2_EXT2_BLOCK_SIZE(data)(__le32_to_cpu(data->sblock.log2_block_size) + 1) /* Log2 size of ext2 block in bytes. */ #define LOG2_BLOCK_SIZE(data) (__le32_to_cpu(data->sblock.log2_block_size) + 10) /* The size of an ext2 block in bytes. */ #define EXT2_BLOCK_SIZE(data) (1 << LOG2_BLOCK_SIZE(data)) #define EXT2_GOOD_OLD_REV 0 /* The good old (original) format */ #define EXT2_DYNAMIC_REV 1 /* V2 format w/ dynamic inode sizes */ #define EXT2_GOOD_OLD_INODE_SIZE 128 uint32_t ext2_inode_size = EXT2_GOOD_OLD_INODE_SIZE; /* The ext2 superblock. */ struct ext2_sblock { uint32_t total_inodes; uint32_t total_blocks; uint32_t reserved_blocks; uint32_t free_blocks; uint32_t free_inodes; uint32_t first_data_block; uint32_t log2_block_size; uint32_t log2_fragment_size; uint32_t blocks_per_group; uint32_t fragments_per_group; uint32_t inodes_per_group; uint32_t mtime; uint32_t utime; uint16_t mnt_count; uint16_t max_mnt_count; uint16_t magic; uint16_t fs_state; uint16_t error_handling; uint16_t minor_revision_level; uint32_t lastcheck; uint32_t checkinterval; uint32_t creator_os; uint32_t revision_level; uint16_t uid_reserved; uint16_t gid_reserved; uint32_t first_inode; uint16_t inode_size; uint16_t block_group_number; uint32_t feature_compatibility; uint32_t feature_incompat; uint32_t feature_ro_compat; uint32_t unique_id[4]; char volume_name[16]; char last_mounted_on[64]; uint32_t compression_info; }; /* The ext2 blockgroup. */ struct ext2_block_group { uint32_t block_id; uint32_t inode_id; uint32_t inode_table_id; uint16_t free_blocks; uint16_t free_inodes; uint16_t pad; uint32_t reserved[3]; }; /* The ext2 inode. */ struct ext2_inode { uint16_t mode; uint16_t uid; uint32_t size; uint32_t atime; uint32_t ctime; uint32_t mtime; uint32_t dtime; uint16_t gid; uint16_t nlinks; uint32_t blockcnt; /* Blocks of 512 bytes!! */ uint32_t flags; uint32_t osd1; union { struct datablocks { uint32_t dir_blocks[INDIRECT_BLOCKS]; uint32_t indir_block; uint32_t double_indir_block; uint32_t tripple_indir_block; } blocks; char symlink[60]; } b; uint32_t version; uint32_t acl; uint32_t dir_acl; uint32_t fragment_addr; uint32_t osd2[3]; }; /* The header of an ext2 directory entry. */ struct ext2_dirent { uint32_t inode; uint16_t direntlen; uint8_t namelen; uint8_t filetype; }; struct ext2fs_node { struct ext2_data *data; struct ext2_inode inode; int ino; int inode_read; }; /* Information about a "mounted" ext2 filesystem. */ struct ext2_data { struct ext2_sblock sblock; struct ext2_inode *inode; struct ext2fs_node diropen; }; typedef struct ext2fs_node *ext2fs_node_t; struct ext2_data *ext2fs_root = NULL; ext2fs_node_t ext2fs_file = NULL; int symlinknest = 0; uint32_t *indir1_block = NULL; int indir1_size = 0; int indir1_blkno = -1; uint32_t *indir2_block = NULL; int indir2_size = 0; int indir2_blkno = -1; static int ext2fs_blockgroup (struct ext2_data *data, int group, struct ext2_block_group *blkgrp) { #ifdef DEBUG puts("ext2fs read blockgroup\n"); #endif return ext2fs_devread (((__le32_to_cpu(data->sblock.first_data_block) + 1) << LOG2_EXT2_BLOCK_SIZE(data)), group * sizeof(struct ext2_block_group), sizeof(struct ext2_block_group),(char *) blkgrp); } static int ext2fs_read_inode (struct ext2_data *data, int ino, struct ext2_inode *inode) { struct ext2_block_group blkgrp; struct ext2_sblock *sblock = &data->sblock; int inodes_per_block; int status; unsigned int blkno; unsigned int blkoff; /* It is easier to calculate if the first inode is 0. */ ino--; #ifdef DEBUG puts("ext2fs read inode %d\n", ino); #endif status = ext2fs_blockgroup(data, ino / __le32_to_cpu(sblock->inodes_per_group), &blkgrp); if (status == 0) return 0; inodes_per_block = EXT2_BLOCK_SIZE(data) / ext2_inode_size; blkno =(ino % __le32_to_cpu(sblock->inodes_per_group)) / inodes_per_block; blkoff =(ino % __le32_to_cpu(sblock->inodes_per_group)) % inodes_per_block; #ifdef DEBUG puts("ext2fs read inode blkno %d blkoff %d\n", blkno, blkoff); #endif /* Read the inode. */ status = ext2fs_devread((__le32_to_cpu(blkgrp.inode_table_id) + blkno) << LOG2_EXT2_BLOCK_SIZE(data), ext2_inode_size * blkoff, sizeof(struct ext2_inode),(char *) inode); return !!status; } void ext2fs_free_node(ext2fs_node_t node, ext2fs_node_t currroot) { if ((node != &ext2fs_root->diropen) &&(node != currroot)) { free(node); } } static int ext2fs_read_block(ext2fs_node_t node, int fileblock) { struct ext2_data *data = node->data; struct ext2_inode *inode = &node->inode; int blknr; int blksz = EXT2_BLOCK_SIZE(data); int log2_blksz = LOG2_EXT2_BLOCK_SIZE(data); int status; /* Direct blocks. */ if (fileblock < INDIRECT_BLOCKS) { blknr = __le32_to_cpu(inode->b.blocks.dir_blocks[fileblock]); } /* Indirect. */ else if (fileblock <(INDIRECT_BLOCKS +(blksz / 4))) { if (indir1_block == NULL) { indir1_block =(uint32_t *) malloc(blksz); if (indir1_block == NULL) { puts("** ext2fs read block(indir 1) malloc failed. **\n"); return -1; } indir1_size = blksz; indir1_blkno = -1; } if (blksz != indir1_size) { free(indir1_block); indir1_block = NULL; indir1_size = 0; indir1_blkno = -1; indir1_block =(uint32_t *) malloc(blksz); if (indir1_block == NULL) { puts("** ext2fs read block(indir 1) malloc failed. **\n"); return -1; } indir1_size = blksz; } if ((__le32_to_cpu(inode->b.blocks.indir_block) << log2_blksz) != indir1_blkno) { status = ext2fs_devread(__le32_to_cpu(inode->b.blocks.indir_block) << log2_blksz, 0, blksz, (char *) indir1_block); if (status == 0) { puts("** ext2fs read block(indir 1) failed. **\n"); return 0; } indir1_blkno = __le32_to_cpu(inode->b.blocks. indir_block) << log2_blksz; } blknr = __le32_to_cpu(indir1_block [fileblock - INDIRECT_BLOCKS]); } /* Double indirect. */ else if (fileblock < (INDIRECT_BLOCKS +(blksz / 4 *(blksz / 4 + 1)))) { unsigned int perblock = blksz / 4; unsigned int rblock = fileblock -(INDIRECT_BLOCKS + blksz / 4); if (indir1_block == NULL) { indir1_block =(uint32_t *) malloc(blksz); if (indir1_block == NULL) { puts("** ext2fs read block(indir 2 1) malloc failed. **\n"); return -1; } indir1_size = blksz; indir1_blkno = -1; } if (blksz != indir1_size) { free(indir1_block); indir1_block = NULL; indir1_size = 0; indir1_blkno = -1; indir1_block =(uint32_t *) malloc(blksz); if (indir1_block == NULL) { puts("** ext2fs read block(indir 2 1) malloc failed. **\n"); return -1; } indir1_size = blksz; } if ((__le32_to_cpu(inode->b.blocks.double_indir_block) << log2_blksz) != indir1_blkno) { status = ext2fs_devread(__le32_to_cpu(inode->b.blocks.double_indir_block) << log2_blksz, 0, blksz, (char *) indir1_block); if (status == 0) { puts("** ext2fs read block(indir 2 1) failed. **\n"); return -1; } indir1_blkno = __le32_to_cpu(inode->b.blocks.double_indir_block) << log2_blksz; } if (indir2_block == NULL) { indir2_block =(uint32_t *) malloc(blksz); if (indir2_block == NULL) { puts("** ext2fs read block(indir 2 2) malloc failed. **\n"); return -1; } indir2_size = blksz; indir2_blkno = -1; } if (blksz != indir2_size) { free(indir2_block); indir2_block = NULL; indir2_size = 0; indir2_blkno = -1; indir2_block =(uint32_t *) malloc(blksz); if (indir2_block == NULL) { puts("** ext2fs read block(indir 2 2) malloc failed. **\n"); return -1; } indir2_size = blksz; } if ((__le32_to_cpu(indir1_block[rblock / perblock]) << log2_blksz) != indir1_blkno) { status = ext2fs_devread(__le32_to_cpu(indir1_block[rblock / perblock]) << log2_blksz, 0, blksz, (char *) indir2_block); if (status == 0) { puts("** ext2fs read block(indir 2 2) failed. **\n"); return -1; } indir2_blkno = __le32_to_cpu(indir1_block[rblock / perblock]) << log2_blksz; } blknr = __le32_to_cpu(indir2_block[rblock % perblock]); } /* Tripple indirect. */ else { puts("** ext2fs doesn't support tripple indirect blocks. **\n"); return -1; } #ifdef DEBUG printf("ext2fs_read_block %08x\n", blknr); #endif return blknr; } int ext2fs_read_file (ext2fs_node_t node, int pos, unsigned int len, char *buf) { int i; int blockcnt; int log2blocksize = LOG2_EXT2_BLOCK_SIZE(node->data); int blocksize = 1 <<(log2blocksize + DISK_SECTOR_BITS); unsigned int filesize = __le32_to_cpu(node->inode.size); /* Adjust len so it we can't read past the end of the file. */ if (len > filesize) { len = filesize; } blockcnt = ((len + pos) + blocksize - 1) / blocksize; for(i = pos / blocksize; i < blockcnt; i++) { int blknr; int blockoff = pos % blocksize; int blockend = blocksize; int skipfirst = 0; blknr = ext2fs_read_block(node, i); if (blknr < 0) return -1; blknr = blknr << log2blocksize; /* Last block. */ if (i == blockcnt - 1) { blockend =(len + pos) % blocksize; /* The last portion is exactly blocksize. */ if (!blockend) { blockend = blocksize; } } /* First block. */ if (i == pos / blocksize) { skipfirst = blockoff; blockend -= skipfirst; } /* If the block number is 0 this block is not stored on disk but is zero filled instead. */ if (blknr) { int status; status = ext2fs_devread(blknr, skipfirst, blockend, buf); if (status == 0) return -1; } else memset(buf, 0, blocksize - skipfirst); buf += blocksize - skipfirst; } return(len); } static int ext2fs_iterate_dir(ext2fs_node_t dir, char *name, ext2fs_node_t * fnode, int *ftype) { unsigned int fpos = 0; int status; struct ext2fs_node *diro =(struct ext2fs_node *) dir; #ifdef DEBUG if (name != NULL) printf("Iterate dir %s\n", name); #endif /* of DEBUG */ if (!diro->inode_read) { status = ext2fs_read_inode(diro->data, diro->ino, &diro->inode); if (status == 0) { printdec(diro->ino); puts("failed to read inode\n"); return(0); } } else { puts("fail\n"); } printdec(fpos); puts(" "); printdec(diro->inode.size); puts("\n"); /* Search the file. */ while (fpos < __le32_to_cpu(diro->inode.size)) { struct ext2_dirent dirent; status = ext2fs_read_file(diro, fpos, sizeof(struct ext2_dirent), (char *) &dirent); if (status < 1) { puts("ext2fs_read_file ret < 1\n"); return 0; } if (dirent.namelen != 0) { char filename[256]; ext2fs_node_t fdiro; int type = FILETYPE_UNKNOWN; status = ext2fs_read_file(diro, fpos + sizeof(struct ext2_dirent), dirent.namelen, filename); if (status < 1) { puts("ext2fs_read_file fail 2\n"); return(0); } fdiro = malloc(sizeof(struct ext2fs_node)); if (!fdiro) { puts("malloc fail\n"); return(0); } fdiro->data = diro->data; fdiro->ino = __le32_to_cpu(dirent.inode); filename[dirent.namelen] = '\0'; if (dirent.filetype != FILETYPE_UNKNOWN) { fdiro->inode_read = 0; if (dirent.filetype == FILETYPE_DIRECTORY) { type = FILETYPE_DIRECTORY; } else if (dirent.filetype == FILETYPE_SYMLINK) { type = FILETYPE_SYMLINK; } else if (dirent.filetype == FILETYPE_REG) { type = FILETYPE_REG; } } else { /* The filetype can not be read from the dirent, get it from inode */ status = ext2fs_read_inode(diro->data, __le32_to_cpu(dirent.inode), &fdiro->inode); if (status == 0) { puts("inner ext2fs_read_inode fail\n"); free(fdiro); return(0); } fdiro->inode_read = 1; if ((__le16_to_cpu(fdiro->inode.mode) & FILETYPE_INO_MASK) == FILETYPE_INO_DIRECTORY) { type = FILETYPE_DIRECTORY; } else if ((__le16_to_cpu(fdiro->inode.mode) & FILETYPE_INO_MASK) == FILETYPE_INO_SYMLINK) { type = FILETYPE_SYMLINK; } else if ((__le16_to_cpu(fdiro->inode.mode) & FILETYPE_INO_MASK) == FILETYPE_INO_REG) { type = FILETYPE_REG; } } #ifdef DEBUG printf("iterate >%s<\n", filename); #endif /* of DEBUG */ if ((name != NULL) &&(fnode != NULL) &&(ftype != NULL)) { if (strcmp(filename, name) == 0) { *ftype = type; *fnode = fdiro; return 1; } } else { if (fdiro->inode_read == 0) { status = ext2fs_read_inode(diro->data, __le32_to_cpu(dirent.inode), &fdiro->inode); if (status == 0) { puts("ext2fs_read_inode 3 fail\n"); free(fdiro); return(0); } fdiro->inode_read = 1; } switch(type) { case FILETYPE_DIRECTORY: puts(" "); break; case FILETYPE_SYMLINK: puts(" "); break; case FILETYPE_REG: puts(" "); break; default: puts("< ? > "); break; } printdec(__le32_to_cpu(fdiro->inode.size)); puts(" "); puts(filename); puts("\n"); } free(fdiro); } fpos += __le16_to_cpu(dirent.direntlen); } return 0; } static char *ext2fs_read_symlink(ext2fs_node_t node) { char *symlink; struct ext2fs_node *diro = node; int status; if (!diro->inode_read) { status = ext2fs_read_inode(diro->data, diro->ino, &diro->inode); if (status == 0) { return(0); } } symlink = malloc(__le32_to_cpu(diro->inode.size) + 1); if (!symlink) return(0); /* If the filesize of the symlink is bigger than 60 the symlink is stored in a separate block, otherwise it is stored in the inode. */ if (__le32_to_cpu(diro->inode.size) <= 60) { strncpy(symlink, diro->inode.b.symlink, __le32_to_cpu(diro->inode.size)); } else { status = ext2fs_read_file(diro, 0, __le32_to_cpu(diro->inode.size), symlink); if (status == 0) { free(symlink); return(0); } } symlink[__le32_to_cpu(diro->inode.size)] = '\0'; return(symlink); } int ext2fs_find_file1 (const char *currpath, ext2fs_node_t currroot, ext2fs_node_t * currfound, int *foundtype) { char fpath[strlen(currpath) + 1]; char *name = fpath; char *next; int status; int type = FILETYPE_DIRECTORY; ext2fs_node_t currnode = currroot; ext2fs_node_t oldnode = currroot; strncpy(fpath, currpath, strlen(currpath) + 1); /* Remove all leading slashes. */ while (*name == '/') name++; if (!*name) { *currfound = currnode; return 1; } for(;;) { int found; /* Extract the actual part from the pathname. */ next = strchr(name, '/'); if (next) { /* Remove all leading slashes. */ while (*next == '/') { *(next++) = '\0'; } } /* At this point it is expected that the current node is a directory, check if this is true. */ if (type != FILETYPE_DIRECTORY) { ext2fs_free_node(currnode, currroot); return(0); } oldnode = currnode; /* Iterate over the directory. */ found = ext2fs_iterate_dir(currnode, name, &currnode, &type); if (found == 0) return(0); if (found == -1) break; /* Read in the symlink and follow it. */ if (type == FILETYPE_SYMLINK) { char *symlink; /* Test if the symlink does not loop. */ if (++symlinknest == 8) { ext2fs_free_node(currnode, currroot); ext2fs_free_node(oldnode, currroot); return(0); } symlink = ext2fs_read_symlink(currnode); ext2fs_free_node(currnode, currroot); if (!symlink) { ext2fs_free_node(oldnode, currroot); return(0); } #ifdef DEBUG printf("Got symlink >%s<\n", symlink); #endif /* of DEBUG */ /* The symlink is an absolute path, go back to the root inode. */ if (symlink[0] == '/') { ext2fs_free_node(oldnode, currroot); oldnode = &ext2fs_root->diropen; } /* Lookup the node the symlink points to. */ status = ext2fs_find_file1(symlink, oldnode, &currnode, &type); free(symlink); if (status == 0) { ext2fs_free_node(oldnode, currroot); return(0); } } ext2fs_free_node(oldnode, currroot); /* Found the node! */ if (!next || *next == '\0') { *currfound = currnode; *foundtype = type; return(1); } name = next; } return -1; } int ext2fs_find_file (const char *path, ext2fs_node_t rootnode, ext2fs_node_t * foundnode, int expecttype) { int status; int foundtype = FILETYPE_DIRECTORY; symlinknest = 0; if (!path) return 0; status = ext2fs_find_file1(path, rootnode, foundnode, &foundtype); if (status == 0) return 0; /* Check if the node that was found was of the expected type. */ if ((expecttype == FILETYPE_REG) &&(foundtype != expecttype)) { return 0; } else if ((expecttype == FILETYPE_DIRECTORY) &&(foundtype != expecttype)) { return 0; } return 1; } int ext2fs_ls(char *dirname) { ext2fs_node_t dirnode; int status; if (ext2fs_root == NULL) return 0; status = ext2fs_find_file(dirname, &ext2fs_root->diropen, &dirnode, FILETYPE_DIRECTORY); if (status != 1) { puts("** Can not find directory. **\n"); return 1; } ext2fs_iterate_dir(dirnode, NULL, NULL, NULL); ext2fs_free_node(dirnode, &ext2fs_root->diropen); return 0; } int ext2fs_open(const char *filename) { ext2fs_node_t fdiro = NULL; int status; int len; int ret = -1; if (ext2fs_root == NULL) goto fail; ext2fs_file = NULL; status = ext2fs_find_file(filename, &ext2fs_root->diropen, &fdiro, FILETYPE_REG); if (status == 0) { ret = -2; goto fail; } if (!fdiro->inode_read) { status = ext2fs_read_inode(fdiro->data, fdiro->ino, &fdiro->inode); if (status == 0) { ret = -3; goto fail; } } len = __le32_to_cpu(fdiro->inode.size); ext2fs_file = fdiro; return(len); fail: ext2fs_free_node(fdiro, &ext2fs_root->diropen); return ret; } int ext2fs_close(void ) { if ((ext2fs_file != NULL) &&(ext2fs_root != NULL)) { ext2fs_free_node(ext2fs_file, &ext2fs_root->diropen); ext2fs_file = NULL; } if (ext2fs_root != NULL) { free(ext2fs_root); ext2fs_root = NULL; } if (indir1_block != NULL) { free(indir1_block); indir1_block = NULL; indir1_size = 0; indir1_blkno = -1; } if (indir2_block != NULL) { free(indir2_block); indir2_block = NULL; indir2_size = 0; indir2_blkno = -1; } return(0); } int ext2fs_read(char *buf, unsigned len) { int status; if (ext2fs_root == NULL) return 0; if (ext2fs_file == NULL) return 0; status = ext2fs_read_file(ext2fs_file, 0, len, buf); return status; } int ext2fs_mount(void) { struct ext2_data *data; int status; data = malloc(sizeof(struct ext2_data)); if (!data) return 0; /* Read the superblock. */ status = ext2fs_devread(1 * 2, 0, sizeof(struct ext2_sblock), (char *) &data->sblock); if (!status) goto fail; /* Make sure this is an ext2 filesystem. */ if (__le16_to_cpu(data->sblock.magic) != EXT2_MAGIC) goto fail; if (__le32_to_cpu(data->sblock.revision_level) == EXT2_GOOD_OLD_REV) ext2_inode_size = EXT2_GOOD_OLD_INODE_SIZE; else ext2_inode_size = __le16_to_cpu (data->sblock.inode_size); data->diropen.data = data; data->diropen.ino = 2; data->diropen.inode_read = 1; data->inode = &data->diropen.inode; status = ext2fs_read_inode(data, 2, data->inode); if (status == 0) goto fail; ext2fs_root = data; return 1; fail: puts("Failed to mount ext2 filesystem...\n"); free(data); ext2fs_root = NULL; return 0; }