/* ext2.c - Second Extended filesystem */ /* * PUPA -- Preliminary Universal Programming Architecture for GRUB * Copyright (C) 2003 Marco Gerards . * * 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_DIRECTORY 2 #define FILETYPE_SYMLINK 7 #include #include #include #include #include #include #include /* Log2 size of ext2 block in 512 blocks. */ #define LOG2_EXT2_BLOCK_SIZE(data) \ (pupa_le_to_cpu32 (data->sblock.log2_block_size) + 1) /* Log2 size of ext2 block in bytes. */ #define LOG2_BLOCK_SIZE(data) \ (pupa_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 pupa_ext_sblock { pupa_uint32_t total_inodes; pupa_uint32_t total_blocks; pupa_uint32_t reserved_blocks; pupa_uint32_t free_blocks; pupa_uint32_t free_inodes; pupa_uint32_t first_data_block; pupa_uint32_t log2_block_size; pupa_uint32_t log2_fragment_size; pupa_uint32_t blocks_per_group; pupa_uint32_t fragments_per_group; pupa_uint32_t inodes_per_group; pupa_uint32_t mtime; pupa_uint32_t utime; pupa_uint16_t mnt_count; pupa_uint16_t max_mnt_count; pupa_uint16_t magic; pupa_uint16_t fs_state; pupa_uint16_t error_handling; pupa_uint16_t minor_revision_level; pupa_uint32_t lastcheck; pupa_uint32_t checkinterval; pupa_uint32_t creator_os; pupa_uint32_t revision_level; pupa_uint16_t uid_reserved; pupa_uint16_t gid_reserved; pupa_uint32_t first_inode; pupa_uint16_t inode_size; pupa_uint16_t block_group_number; pupa_uint32_t feature_compatibility; pupa_uint32_t feature_incompat; pupa_uint32_t feature_ro_compat; pupa_uint32_t unique_id[4]; char volume_name[16]; char last_mounted_on[64]; pupa_uint32_t compression_info; }; /* The ext2 blockgroup. */ struct ext2_block_group { pupa_uint32_t block_id; pupa_uint32_t inode_id; pupa_uint32_t inode_table_id; pupa_uint16_t free_blocks; pupa_uint16_t free_inodes; pupa_uint16_t pad; pupa_uint32_t reserved[3]; }; /* The ext2 inode. */ struct pupa_ext2_inode { pupa_uint16_t mode; pupa_uint16_t uid; pupa_uint32_t size; pupa_uint32_t atime; pupa_uint32_t ctime; pupa_uint32_t mtime; pupa_uint32_t dtime; pupa_uint16_t gid; pupa_uint16_t nlinks; pupa_uint32_t blockcnt; /* Blocks of 512 bytes!! */ pupa_uint32_t flags; pupa_uint32_t osd1; union { struct datablocks { pupa_uint32_t dir_blocks[INDIRECT_BLOCKS]; pupa_uint32_t indir_block; pupa_uint32_t double_indir_block; pupa_uint32_t tripple_indir_block; }; char symlink[60]; }; pupa_uint32_t version; pupa_uint32_t acl; pupa_uint32_t dir_acl; pupa_uint32_t fragment_addr; pupa_uint32_t osd2[3]; }; /* The header of an ext2 directory entry. */ struct ext2_dirent { pupa_uint32_t inode; pupa_uint16_t direntlen; pupa_uint8_t namelen; pupa_uint8_t filetype; }; /* Information about a "mounted" ext2 filesystem. */ struct pupa_ext2_data { struct pupa_ext_sblock sblock; pupa_disk_t disk; struct pupa_ext2_inode inode; }; #ifndef PUPA_UTIL static pupa_dl_t my_mod; #endif /* Read into BLKGRP the blockgroup descriptor of blockgroup GROUP of the mounted filesystem DATA. */ inline static pupa_err_t pupa_ext2_blockgroup (struct pupa_ext2_data *data, int group, struct ext2_block_group *blkgrp) { return pupa_disk_read (data->disk, ((pupa_le_to_cpu32 (data->sblock.first_data_block) + 1) << LOG2_EXT2_BLOCK_SIZE (data)), group * sizeof (struct ext2_block_group), sizeof (struct ext2_block_group), (char *) blkgrp); } /* Return in BLOCK the on disk block number of block FILEBLOCK in the opened file descibed by DATA. If this block is not stored on disk in case of a sparse file return 0. */ static pupa_err_t pupa_ext2_get_file_block (struct pupa_ext2_data *data, int fileblock, int *block) { int blknr; struct pupa_ext2_inode *inode = &data->inode; /* Direct blocks. */ if (fileblock < INDIRECT_BLOCKS) blknr = pupa_le_to_cpu32 (inode->dir_blocks[fileblock]); /* Indirect. */ else if (fileblock < INDIRECT_BLOCKS + EXT2_BLOCK_SIZE (data) / 4) { pupa_uint32_t indir[EXT2_BLOCK_SIZE (data) / 4]; if (pupa_disk_read (data->disk, pupa_le_to_cpu32 (inode->indir_block) << LOG2_EXT2_BLOCK_SIZE (data), 0, EXT2_BLOCK_SIZE (data), (char *) indir)) return pupa_errno; blknr = pupa_le_to_cpu32 (indir[fileblock - INDIRECT_BLOCKS]); } /* Double indirect. */ else if (fileblock < INDIRECT_BLOCKS + EXT2_BLOCK_SIZE (data) / 4 * (EXT2_BLOCK_SIZE (data) / 4 + 1)) { unsigned int perblock = EXT2_BLOCK_SIZE (data) / 4; unsigned int rblock = fileblock - (INDIRECT_BLOCKS + EXT2_BLOCK_SIZE (data) / 4); pupa_uint32_t indir[EXT2_BLOCK_SIZE (data) / 4]; if (pupa_disk_read (data->disk, pupa_le_to_cpu32 (inode->double_indir_block) << LOG2_EXT2_BLOCK_SIZE (data), 0, EXT2_BLOCK_SIZE (data), (char *) indir)) return pupa_errno; if (pupa_disk_read (data->disk, pupa_le_to_cpu32 (indir[rblock / perblock]) << LOG2_EXT2_BLOCK_SIZE (data), 0, EXT2_BLOCK_SIZE (data), (char *) indir)) return pupa_errno; blknr = pupa_le_to_cpu32 (indir[rblock % perblock]); } /* Tripple indirect. */ else { pupa_error (PUPA_ERR_NOT_IMPLEMENTED_YET, "ext2fs doesn't support tripple indirect blocks"); return pupa_errno; } *block = blknr; return 0; } /* Read LEN bytes from the file described by DATA starting with byte POS. Return the amount of read bytes in READ. */ static pupa_err_t pupa_ext2_read_file (struct pupa_ext2_data *data, int pos, unsigned int len, char *buf) { int i; int blockcnt; /* Adjust len so it we can't read past the end of the file. */ if (len > pupa_le_to_cpu32 (data->inode.size)) len = pupa_le_to_cpu32 (data->inode.size); blockcnt = ((len + pos) + EXT2_BLOCK_SIZE (data) - 1) / EXT2_BLOCK_SIZE (data); for (i = pos / EXT2_BLOCK_SIZE (data); i < blockcnt; i++) { int blknr; int blockoff = pos % EXT2_BLOCK_SIZE (data); int blockend = (len + pos) % EXT2_BLOCK_SIZE (data); int skipfirst = 0; pupa_ext2_get_file_block (data, i, &blknr); if (pupa_errno) return pupa_errno; blknr = blknr << LOG2_EXT2_BLOCK_SIZE (data); /* First block. */ if (i == pos / EXT2_BLOCK_SIZE (data)) skipfirst = blockoff; if (!blockend) blockend = EXT2_BLOCK_SIZE (data); blockend -= skipfirst; /* If the block number is 0 this block is not stored on disk but is zero filled instead. */ if (blknr) { pupa_disk_read (data->disk, blknr, skipfirst, blockend, buf); if (pupa_errno) return pupa_errno; } else pupa_memset (buf, EXT2_BLOCK_SIZE (data) - skipfirst, 0); buf += EXT2_BLOCK_SIZE (data) - skipfirst; } return len; } /* Read the inode INO for the file described by DATA into INODE. */ static pupa_err_t pupa_ext2_read_inode (struct pupa_ext2_data *data, int ino, struct pupa_ext2_inode *inode) { struct ext2_block_group blkgrp; struct pupa_ext_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--; pupa_ext2_blockgroup (data, ino / pupa_le_to_cpu32 (sblock->inodes_per_group), &blkgrp); if (pupa_errno) return pupa_errno; inodes_per_block = EXT2_BLOCK_SIZE (data) / 128; blkno = (ino % pupa_le_to_cpu32 (sblock->inodes_per_group)) / inodes_per_block; blkoff = (ino % pupa_le_to_cpu32 (sblock->inodes_per_group)) % inodes_per_block; /* Read the inode. */ if (pupa_disk_read (data->disk, ((pupa_le_to_cpu32 (blkgrp.inode_table_id) + blkno) << LOG2_EXT2_BLOCK_SIZE (data)), sizeof (struct pupa_ext2_inode) * blkoff, sizeof (struct pupa_ext2_inode), (char *) inode)) return pupa_errno; return 0; } static struct pupa_ext2_data * pupa_ext2_mount (pupa_disk_t disk) { struct pupa_ext2_data *data; data = pupa_malloc (sizeof (struct pupa_ext2_data)); if (!data) return 0; /* Read the superblock. */ pupa_disk_read (disk, 1 * 2, 0, sizeof (struct pupa_ext_sblock), (char *) &data->sblock); if (pupa_errno) goto fail; /* Make sure this is an ext2 filesystem. */ if (pupa_le_to_cpu16 (data->sblock.magic) != EXT2_MAGIC) goto fail; data->disk = disk; return data; fail: pupa_error (PUPA_ERR_BAD_FS, "not an ext2 filesystem"); pupa_free (data); return 0; } /* Find the file with the pathname PATH on the filesystem described by DATA. Return its inode number in INO. */ static pupa_err_t pupa_ext2_find_file (struct pupa_ext2_data *data, const char *path, int *ino) { int blocksize = EXT2_BLOCK_SIZE (data) << pupa_le_to_cpu32 (data->sblock.log2_block_size); struct pupa_ext2_inode *inode = &data->inode; int currinode = 2; int symlinkcnt = 0; char fpath[EXT2_PATH_MAX]; char *name = fpath; pupa_strncpy (fpath, path, EXT2_PATH_MAX); if (!name || name[0] != '/') { pupa_error (PUPA_ERR_BAD_FILENAME, "bad filename"); return pupa_errno; } /* Skip the first slash. */ name++; if (!*name) { *ino = 2; return 0; } /* Remove trailing "/". */ if (name[pupa_strlen (name) - 1] =='/') name[pupa_strlen (name) - 1] = '\0'; while (*name) { unsigned int fpos = 0; char *next; int namesize; /* Extract the actual part from the pathname. */ next = pupa_strchr (name, '/'); if (next) { next[0] = '\0'; next++; } namesize = pupa_strlen (name); /* Open the file. */ pupa_ext2_read_inode (data, currinode, inode); if (pupa_errno) goto fail; /* Search the file. */ while (fpos < pupa_le_to_cpu32 (inode->size)) { struct ext2_dirent dirent; /* Read the directory entry. */ pupa_ext2_read_file (data, fpos, sizeof (struct ext2_dirent), (char *) &dirent); if (pupa_errno) goto fail; if (dirent.namelen != 0) { char filename[dirent.namelen + 1]; /* Read the filename part of this directory entry. */ pupa_ext2_read_file (data, fpos + sizeof (struct ext2_dirent), dirent.namelen, filename); if (pupa_errno) goto fail; filename[dirent.namelen] = '\0'; /* Check if the current directory entry described the file we are looking for. */ if (dirent.namelen == namesize && !pupa_strncmp (name, filename, namesize)) { /* If this is a symlink, follow it. */ if (dirent.filetype == FILETYPE_SYMLINK) { /* XXX: Use malloc instead? */ char symlink[blocksize]; if (++symlinkcnt == EXT2_MAX_SYMLINKCNT) { pupa_error (PUPA_ERR_SYMLINK_LOOP, "too deep nesting of symlinks"); goto fail; } /* Read the symlink. */ pupa_ext2_read_inode (data, pupa_le_to_cpu32 (dirent.inode), inode); /* 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 (pupa_le_to_cpu32 (inode->size) <= 60) pupa_strncpy (symlink, inode->symlink, pupa_le_to_cpu32 (inode->size)); else { pupa_ext2_read_file (data, 0, pupa_le_to_cpu32 (inode->size), symlink); if (pupa_errno) goto fail; } symlink[pupa_le_to_cpu32 (inode->size)] = '\0'; /* Check if the symlink is absolute or relative. */ if (symlink[0] == '/') { pupa_strncpy (fpath, symlink, EXT2_PATH_MAX); name = fpath; currinode = 2; } else { char *bak = 0; if (next) { bak = pupa_strdup (next); if (!bak) goto fail; } /* Relative symlink, construct the new path. */ pupa_strcpy (fpath, symlink); name = fpath; if (next) { pupa_strcat (name, "/"); pupa_strcat (name, bak); pupa_free (bak); } } fpos = 0; break; } if (next) { currinode = pupa_le_to_cpu32 (dirent.inode); name = next; if (dirent.filetype != FILETYPE_DIRECTORY) { pupa_error (PUPA_ERR_BAD_FILE_TYPE, "not a directory"); goto fail; } break; } else /* Found it! */ { *ino = pupa_le_to_cpu32 (dirent.inode); return 0; } } } /* Move to next directory entry. */ fpos += pupa_le_to_cpu16 (dirent.direntlen); } /* The complete directory was read and no matching file was found. */ if (fpos >= pupa_le_to_cpu32 (inode->size)) { pupa_error (PUPA_ERR_FILE_NOT_FOUND, "file not found"); goto fail; } } fail: return pupa_errno; } /* Open a file named NAME and initialize FILE. */ static pupa_err_t pupa_ext2_open (struct pupa_file *file, const char *name) { struct pupa_ext2_data *data; int ino; #ifndef PUPA_UTIL pupa_dl_ref (my_mod); #endif data = pupa_ext2_mount (file->device->disk); if (!data) goto fail; pupa_ext2_find_file (data, name, &ino); if (pupa_errno) goto fail; pupa_ext2_read_inode (data, ino, &data->inode); if (pupa_errno) goto fail; if (!(pupa_le_to_cpu16 (data->inode.mode) & 0100000)) { pupa_error (PUPA_ERR_BAD_FILE_TYPE, "not a regular file"); goto fail; } file->size = pupa_le_to_cpu32 (data->inode.size); file->data = data; file->offset = 0; return 0; fail: pupa_free (data); #ifndef PUPA_UTIL pupa_dl_unref (my_mod); #endif return pupa_errno; } static pupa_err_t pupa_ext2_close (pupa_file_t file) { pupa_free (file->data); #ifndef PUPA_UTIL pupa_dl_unref (my_mod); #endif return pupa_errno; } /* Read LEN bytes data from FILE into BUF. */ static pupa_ssize_t pupa_ext2_read (pupa_file_t file, char *buf, pupa_ssize_t len) { struct pupa_ext2_data *data = (struct pupa_ext2_data *) file->data; return pupa_ext2_read_file (data, file->offset, len, buf); } static pupa_err_t pupa_ext2_dir (pupa_device_t device, const char *path, int (*hook) (const char *filename, int dir)) { struct pupa_ext2_data *data = 0;; int ino; unsigned int fpos = 0; #ifndef PUPA_UTIL pupa_dl_ref (my_mod); #endif data = pupa_ext2_mount (device->disk); if (!data) goto fail; pupa_ext2_find_file (data, (char *) path, &ino); if (pupa_errno) goto fail; pupa_ext2_read_inode (data, ino, &data->inode); if (pupa_errno) goto fail; if (!(pupa_le_to_cpu16 (data->inode.mode) & 040000)) { pupa_error (PUPA_ERR_BAD_FILE_TYPE, "not a directory"); goto fail; } /* Search the file. */ while (fpos < pupa_le_to_cpu32 (data->inode.size)) { struct ext2_dirent dirent; pupa_ext2_read_file (data, fpos, sizeof (struct ext2_dirent), (char *) &dirent); if (pupa_errno) goto fail; if (dirent.namelen != 0) { char filename[dirent.namelen + 1]; pupa_ext2_read_file (data, fpos + sizeof (struct ext2_dirent), dirent.namelen, filename); if (pupa_errno) goto fail; filename[dirent.namelen] = '\0'; hook (filename, dirent.filetype == FILETYPE_DIRECTORY); } fpos += pupa_le_to_cpu16 (dirent.direntlen); } fail: pupa_free (data); #ifndef PUPA_UTIL pupa_dl_unref (my_mod); #endif return pupa_errno; } static struct pupa_fs pupa_ext2_fs = { .name = "ext2", .dir = pupa_ext2_dir, .open = pupa_ext2_open, .read = pupa_ext2_read, .close = pupa_ext2_close, .next = 0 }; #ifdef PUPA_UTIL void pupa_ext2_init (void) { pupa_fs_register (&pupa_ext2_fs); } void pupa_ext2_fini (void) { pupa_fs_unregister (&pupa_ext2_fs); } #else /* ! PUPA_UTIL */ PUPA_MOD_INIT { pupa_fs_register (&pupa_ext2_fs); my_mod = mod; } PUPA_MOD_FINI { pupa_fs_unregister (&pupa_ext2_fs); } #endif /* ! PUPA_UTIL */