/* ext2.c - Second Extended filesystem */ /* * GRUB -- GRand Unified Bootloader * Copyright (C) 2003, 2004, 2005 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. */ /* 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 #include #include #include #include #include #include #include #include /* Log2 size of ext2 block in 512 blocks. */ #define LOG2_EXT2_BLOCK_SIZE(data) \ (grub_le_to_cpu32 (data->sblock.log2_block_size) + 1) /* Log2 size of ext2 block in bytes. */ #define LOG2_BLOCK_SIZE(data) \ (grub_le_to_cpu32 (data->sblock.log2_block_size) + 10) /* The size of an ext2 block in bytes. */ #define EXT2_BLOCK_SIZE(data) (1 << LOG2_BLOCK_SIZE(data)) /* The ext2 superblock. */ struct grub_ext2_sblock { grub_uint32_t total_inodes; grub_uint32_t total_blocks; grub_uint32_t reserved_blocks; grub_uint32_t free_blocks; grub_uint32_t free_inodes; grub_uint32_t first_data_block; grub_uint32_t log2_block_size; grub_uint32_t log2_fragment_size; grub_uint32_t blocks_per_group; grub_uint32_t fragments_per_group; grub_uint32_t inodes_per_group; grub_uint32_t mtime; grub_uint32_t utime; grub_uint16_t mnt_count; grub_uint16_t max_mnt_count; grub_uint16_t magic; grub_uint16_t fs_state; grub_uint16_t error_handling; grub_uint16_t minor_revision_level; grub_uint32_t lastcheck; grub_uint32_t checkinterval; grub_uint32_t creator_os; grub_uint32_t revision_level; grub_uint16_t uid_reserved; grub_uint16_t gid_reserved; grub_uint32_t first_inode; grub_uint16_t inode_size; grub_uint16_t block_group_number; grub_uint32_t feature_compatibility; grub_uint32_t feature_incompat; grub_uint32_t feature_ro_compat; grub_uint32_t unique_id[4]; char volume_name[16]; char last_mounted_on[64]; grub_uint32_t compression_info; }; /* The ext2 blockgroup. */ struct grub_ext2_block_group { grub_uint32_t block_id; grub_uint32_t inode_id; grub_uint32_t inode_table_id; grub_uint16_t free_blocks; grub_uint16_t free_inodes; grub_uint16_t pad; grub_uint32_t reserved[3]; }; /* The ext2 inode. */ struct grub_ext2_inode { grub_uint16_t mode; grub_uint16_t uid; grub_uint32_t size; grub_uint32_t atime; grub_uint32_t ctime; grub_uint32_t mtime; grub_uint32_t dtime; grub_uint16_t gid; grub_uint16_t nlinks; grub_uint32_t blockcnt; /* Blocks of 512 bytes!! */ grub_uint32_t flags; grub_uint32_t osd1; union { struct datablocks { grub_uint32_t dir_blocks[INDIRECT_BLOCKS]; grub_uint32_t indir_block; grub_uint32_t double_indir_block; grub_uint32_t tripple_indir_block; } blocks; char symlink[60]; }; grub_uint32_t version; grub_uint32_t acl; grub_uint32_t dir_acl; grub_uint32_t fragment_addr; grub_uint32_t osd2[3]; }; /* The header of an ext2 directory entry. */ struct ext2_dirent { grub_uint32_t inode; grub_uint16_t direntlen; grub_uint8_t namelen; grub_uint8_t filetype; }; struct grub_fshelp_node { struct grub_ext2_data *data; struct grub_ext2_inode inode; int ino; int inode_read; }; /* Information about a "mounted" ext2 filesystem. */ struct grub_ext2_data { struct grub_ext2_sblock sblock; grub_disk_t disk; struct grub_ext2_inode *inode; struct grub_fshelp_node diropen; }; #ifndef GRUB_UTIL static grub_dl_t my_mod; #endif /* Read into BLKGRP the blockgroup descriptor of blockgroup GROUP of the mounted filesystem DATA. */ inline static grub_err_t grub_ext2_blockgroup (struct grub_ext2_data *data, int group, struct grub_ext2_block_group *blkgrp) { return grub_disk_read (data->disk, ((grub_le_to_cpu32 (data->sblock.first_data_block) + 1) << LOG2_EXT2_BLOCK_SIZE (data)), group * sizeof (struct grub_ext2_block_group), sizeof (struct grub_ext2_block_group), (char *) blkgrp); } static int grub_ext2_read_block (grub_fshelp_node_t node, int fileblock) { struct grub_ext2_data *data = node->data; struct grub_ext2_inode *inode = &node->inode; int blknr; int blksz = EXT2_BLOCK_SIZE (data); int log2_blksz = LOG2_EXT2_BLOCK_SIZE (data); /* Direct blocks. */ if (fileblock < INDIRECT_BLOCKS) blknr = grub_le_to_cpu32 (inode->blocks.dir_blocks[fileblock]); /* Indirect. */ else if (fileblock < INDIRECT_BLOCKS + blksz / 4) { grub_uint32_t indir[blksz / 4]; if (grub_disk_read (data->disk, grub_le_to_cpu32 (inode->blocks.indir_block) << log2_blksz, 0, blksz, (char *) indir)) return grub_errno; blknr = grub_le_to_cpu32 (indir[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); grub_uint32_t indir[blksz / 4]; if (grub_disk_read (data->disk, grub_le_to_cpu32 (inode->blocks.double_indir_block) << log2_blksz, 0, blksz, (char *) indir)) return grub_errno; if (grub_disk_read (data->disk, grub_le_to_cpu32 (indir[rblock / perblock]) << log2_blksz, 0, blksz, (char *) indir)) return grub_errno; blknr = grub_le_to_cpu32 (indir[rblock % perblock]); } /* Tripple indirect. */ else { grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET, "ext2fs doesn't support tripple indirect blocks"); blknr = -1; } return blknr; } /* Read LEN bytes from the file described by DATA starting with byte POS. Return the amount of read bytes in READ. */ static grub_ssize_t grub_ext2_read_file (grub_fshelp_node_t node, void (*read_hook) (grub_disk_addr_t sector, unsigned offset, unsigned length), int pos, grub_size_t len, char *buf) { return grub_fshelp_read_file (node->data->disk, node, read_hook, pos, len, buf, grub_ext2_read_block, node->inode.size, LOG2_EXT2_BLOCK_SIZE (node->data)); } /* Read the inode INO for the file described by DATA into INODE. */ static grub_err_t grub_ext2_read_inode (struct grub_ext2_data *data, int ino, struct grub_ext2_inode *inode) { struct grub_ext2_block_group blkgrp; struct grub_ext2_sblock *sblock = &data->sblock; int inodes_per_block; unsigned int blkno; unsigned int blkoff; /* It is easier to calculate if the first inode is 0. */ ino--; grub_ext2_blockgroup (data, ino / grub_le_to_cpu32 (sblock->inodes_per_group), &blkgrp); if (grub_errno) return grub_errno; inodes_per_block = EXT2_BLOCK_SIZE (data) / 128; blkno = (ino % grub_le_to_cpu32 (sblock->inodes_per_group)) / inodes_per_block; blkoff = (ino % grub_le_to_cpu32 (sblock->inodes_per_group)) % inodes_per_block; /* Read the inode. */ if (grub_disk_read (data->disk, ((grub_le_to_cpu32 (blkgrp.inode_table_id) + blkno) << LOG2_EXT2_BLOCK_SIZE (data)), sizeof (struct grub_ext2_inode) * blkoff, sizeof (struct grub_ext2_inode), (char *) inode)) return grub_errno; return 0; } static struct grub_ext2_data * grub_ext2_mount (grub_disk_t disk) { struct grub_ext2_data *data; data = grub_malloc (sizeof (struct grub_ext2_data)); if (!data) return 0; /* Read the superblock. */ grub_disk_read (disk, 1 * 2, 0, sizeof (struct grub_ext2_sblock), (char *) &data->sblock); if (grub_errno) goto fail; /* Make sure this is an ext2 filesystem. */ if (grub_le_to_cpu16 (data->sblock.magic) != EXT2_MAGIC) goto fail; data->diropen.data = data; data->diropen.ino = 2; data->diropen.inode_read = 1; data->inode = &data->diropen.inode; data->disk = disk; grub_ext2_read_inode (data, 2, data->inode); if (grub_errno) goto fail; return data; fail: grub_error (GRUB_ERR_BAD_FS, "not an ext2 filesystem"); grub_free (data); return 0; } static char * grub_ext2_read_symlink (grub_fshelp_node_t node) { char *symlink; struct grub_fshelp_node *diro = node; if (!diro->inode_read) { grub_ext2_read_inode (diro->data, diro->ino, &diro->inode); if (grub_errno) return 0; } symlink = grub_malloc (grub_le_to_cpu32 (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 (grub_le_to_cpu32 (diro->inode.size) <= 60) grub_strncpy (symlink, diro->inode.symlink, grub_le_to_cpu32 (diro->inode.size)); else { grub_ext2_read_file (diro, 0, 0, grub_le_to_cpu32 (diro->inode.size), symlink); if (grub_errno) { grub_free (symlink); return 0; } } symlink[grub_le_to_cpu32 (diro->inode.size)] = '\0'; return symlink; } static int grub_ext2_iterate_dir (grub_fshelp_node_t dir, int NESTED_FUNC_ATTR (*hook) (const char *filename, enum grub_fshelp_filetype filetype, grub_fshelp_node_t node)) { unsigned int fpos = 0; struct grub_fshelp_node *diro = (struct grub_fshelp_node *) dir; if (!diro->inode_read) { grub_ext2_read_inode (diro->data, diro->ino, &diro->inode); if (grub_errno) return 0; } /* Search the file. */ while (fpos < grub_le_to_cpu32 (diro->inode.size)) { struct ext2_dirent dirent; grub_ext2_read_file (diro, 0, fpos, sizeof (struct ext2_dirent), (char *) &dirent); if (grub_errno) return 0; if (dirent.namelen != 0) { char filename[dirent.namelen + 1]; struct grub_fshelp_node *fdiro; enum grub_fshelp_filetype type = GRUB_FSHELP_UNKNOWN; grub_ext2_read_file (diro, 0, fpos + sizeof (struct ext2_dirent), dirent.namelen, filename); if (grub_errno) return 0; fdiro = grub_malloc (sizeof (struct grub_fshelp_node)); if (!fdiro) return 0; fdiro->data = diro->data; fdiro->ino = grub_le_to_cpu32 (dirent.inode); filename[dirent.namelen] = '\0'; if (dirent.filetype != FILETYPE_UNKNOWN) { fdiro->inode_read = 0; if (dirent.filetype == FILETYPE_DIRECTORY) type = GRUB_FSHELP_DIR; else if (dirent.filetype == FILETYPE_SYMLINK) type = GRUB_FSHELP_SYMLINK; else if (dirent.filetype == FILETYPE_REG) type = GRUB_FSHELP_REG; } else { /* The filetype can not be read from the dirent, read the inode to get more information. */ grub_ext2_read_inode (diro->data, grub_le_to_cpu32 (dirent.inode), &fdiro->inode); if (grub_errno) { grub_free (fdiro); return 0; } fdiro->inode_read = 1; if ((grub_le_to_cpu16 (fdiro->inode.mode) & FILETYPE_INO_MASK) == FILETYPE_INO_DIRECTORY) type = GRUB_FSHELP_DIR; else if ((grub_le_to_cpu16 (fdiro->inode.mode) & FILETYPE_INO_MASK) == FILETYPE_INO_SYMLINK) type = GRUB_FSHELP_SYMLINK; else if ((grub_le_to_cpu16 (fdiro->inode.mode) & FILETYPE_INO_MASK) == FILETYPE_INO_REG) type = GRUB_FSHELP_REG; } if (hook (filename, type, fdiro)) return 1; } fpos += grub_le_to_cpu16 (dirent.direntlen); } return 0; } /* Open a file named NAME and initialize FILE. */ static grub_err_t grub_ext2_open (struct grub_file *file, const char *name) { struct grub_ext2_data *data; struct grub_fshelp_node *fdiro = 0; #ifndef GRUB_UTIL grub_dl_ref (my_mod); #endif data = grub_ext2_mount (file->device->disk); if (!data) goto fail; grub_fshelp_find_file (name, &data->diropen, &fdiro, grub_ext2_iterate_dir, grub_ext2_read_symlink, GRUB_FSHELP_REG); if (grub_errno) goto fail; if (!fdiro->inode_read) { grub_ext2_read_inode (data, fdiro->ino, &fdiro->inode); if (grub_errno) goto fail; } grub_memcpy (data->inode, &fdiro->inode, sizeof (struct grub_ext2_inode)); grub_free (fdiro); file->size = grub_le_to_cpu32 (data->inode->size); file->data = data; file->offset = 0; return 0; fail: if (fdiro != &data->diropen) grub_free (fdiro); grub_free (data); #ifndef GRUB_UTIL grub_dl_unref (my_mod); #endif return grub_errno; } static grub_err_t grub_ext2_close (grub_file_t file) { grub_free (file->data); #ifndef GRUB_UTIL grub_dl_unref (my_mod); #endif return GRUB_ERR_NONE; } /* Read LEN bytes data from FILE into BUF. */ static grub_ssize_t grub_ext2_read (grub_file_t file, char *buf, grub_size_t len) { struct grub_ext2_data *data = (struct grub_ext2_data *) file->data; return grub_ext2_read_file (&data->diropen, file->read_hook, file->offset, len, buf); } static grub_err_t grub_ext2_dir (grub_device_t device, const char *path, int (*hook) (const char *filename, int dir)) { struct grub_ext2_data *data = 0;; struct grub_fshelp_node *fdiro = 0; auto int NESTED_FUNC_ATTR iterate (const char *filename, enum grub_fshelp_filetype filetype, grub_fshelp_node_t node); int NESTED_FUNC_ATTR iterate (const char *filename, enum grub_fshelp_filetype filetype, grub_fshelp_node_t node) { grub_free (node); if (filetype == GRUB_FSHELP_DIR) return hook (filename, 1); else return hook (filename, 0); return 0; } #ifndef GRUB_UTIL grub_dl_ref (my_mod); #endif data = grub_ext2_mount (device->disk); if (!data) goto fail; grub_fshelp_find_file (path, &data->diropen, &fdiro, grub_ext2_iterate_dir, grub_ext2_read_symlink, GRUB_FSHELP_DIR); if (grub_errno) goto fail; grub_ext2_iterate_dir (fdiro, iterate); fail: if (fdiro != &data->diropen) grub_free (fdiro); grub_free (data); #ifndef GRUB_UTIL grub_dl_unref (my_mod); #endif return grub_errno; } static grub_err_t grub_ext2_label (grub_device_t device, char **label) { struct grub_ext2_data *data; grub_disk_t disk = device->disk; #ifndef GRUB_UTIL grub_dl_ref (my_mod); #endif data = grub_ext2_mount (disk); if (data) *label = grub_strndup (data->sblock.volume_name, 14); else *label = 0; #ifndef GRUB_UTIL grub_dl_unref (my_mod); #endif grub_free (data); return grub_errno; } static struct grub_fs grub_ext2_fs = { .name = "ext2", .dir = grub_ext2_dir, .open = grub_ext2_open, .read = grub_ext2_read, .close = grub_ext2_close, .label = grub_ext2_label, .next = 0 }; GRUB_MOD_INIT(ext2) { grub_fs_register (&grub_ext2_fs); #ifndef GRUB_UTIL my_mod = mod; #endif } GRUB_MOD_FINI(ext2) { grub_fs_unregister (&grub_ext2_fs); }