// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 2020 Bootlin * * Author: Joao Marcos Costa * * sqfs.c: SquashFS filesystem implementation */ #include #include #include #include #include #include #include #include #include #include #include #include "sqfs_decompressor.h" #include "sqfs_filesystem.h" #include "sqfs_utils.h" static struct squashfs_ctxt ctxt; static int sqfs_disk_read(__u32 block, __u32 nr_blocks, void *buf) { ulong ret; if (!ctxt.cur_dev) return -1; ret = blk_dread(ctxt.cur_dev, ctxt.cur_part_info.start + block, nr_blocks, buf); if (ret != nr_blocks) return -1; return ret; } static int sqfs_read_sblk(struct squashfs_super_block **sblk) { *sblk = malloc_cache_aligned(ctxt.cur_dev->blksz); if (!*sblk) return -ENOMEM; if (sqfs_disk_read(0, 1, *sblk) != 1) { free(*sblk); sblk = NULL; return -EINVAL; } return 0; } static int sqfs_count_tokens(const char *filename) { int token_count = 1, l; for (l = 1; l < strlen(filename); l++) { if (filename[l] == '/') token_count++; } /* Ignore trailing '/' in path */ if (filename[strlen(filename) - 1] == '/') token_count--; if (!token_count) token_count = 1; return token_count; } /* * Calculates how many blocks are needed for the buffer used in sqfs_disk_read. * The memory section (e.g. inode table) start offset and its end (i.e. the next * table start) must be specified. It also calculates the offset from which to * start reading the buffer. */ static int sqfs_calc_n_blks(__le64 start, __le64 end, u64 *offset) { u64 start_, table_size; table_size = le64_to_cpu(end) - le64_to_cpu(start); start_ = le64_to_cpu(start) / ctxt.cur_dev->blksz; *offset = le64_to_cpu(start) - (start_ * ctxt.cur_dev->blksz); return DIV_ROUND_UP(table_size + *offset, ctxt.cur_dev->blksz); } /* * Retrieves fragment block entry and returns true if the fragment block is * compressed */ static int sqfs_frag_lookup(u32 inode_fragment_index, struct squashfs_fragment_block_entry *e) { u64 start, n_blks, src_len, table_offset, start_block; unsigned char *metadata_buffer, *metadata, *table; struct squashfs_fragment_block_entry *entries; struct squashfs_super_block *sblk = ctxt.sblk; unsigned long dest_len; int block, offset, ret; u16 header; metadata_buffer = NULL; entries = NULL; table = NULL; if (inode_fragment_index >= get_unaligned_le32(&sblk->fragments)) return -EINVAL; start = get_unaligned_le64(&sblk->fragment_table_start) / ctxt.cur_dev->blksz; n_blks = sqfs_calc_n_blks(sblk->fragment_table_start, sblk->export_table_start, &table_offset); /* Allocate a proper sized buffer to store the fragment index table */ table = malloc_cache_aligned(n_blks * ctxt.cur_dev->blksz); if (!table) { ret = -ENOMEM; goto out; } if (sqfs_disk_read(start, n_blks, table) < 0) { ret = -EINVAL; goto out; } block = SQFS_FRAGMENT_INDEX(inode_fragment_index); offset = SQFS_FRAGMENT_INDEX_OFFSET(inode_fragment_index); /* * Get the start offset of the metadata block that contains the right * fragment block entry */ start_block = get_unaligned_le64(table + table_offset + block * sizeof(u64)); start = start_block / ctxt.cur_dev->blksz; n_blks = sqfs_calc_n_blks(cpu_to_le64(start_block), sblk->fragment_table_start, &table_offset); metadata_buffer = malloc_cache_aligned(n_blks * ctxt.cur_dev->blksz); if (!metadata_buffer) { ret = -ENOMEM; goto out; } if (sqfs_disk_read(start, n_blks, metadata_buffer) < 0) { ret = -EINVAL; goto out; } /* Every metadata block starts with a 16-bit header */ header = get_unaligned_le16(metadata_buffer + table_offset); metadata = metadata_buffer + table_offset + SQFS_HEADER_SIZE; if (!metadata || !header) { ret = -ENOMEM; goto out; } entries = malloc(SQFS_METADATA_BLOCK_SIZE); if (!entries) { ret = -ENOMEM; goto out; } if (SQFS_COMPRESSED_METADATA(header)) { src_len = SQFS_METADATA_SIZE(header); dest_len = SQFS_METADATA_BLOCK_SIZE; ret = sqfs_decompress(&ctxt, entries, &dest_len, metadata, src_len); if (ret) { ret = -EINVAL; goto out; } } else { memcpy(entries, metadata, SQFS_METADATA_SIZE(header)); } *e = entries[offset]; ret = SQFS_COMPRESSED_BLOCK(e->size); out: free(entries); free(metadata_buffer); free(table); return ret; } /* * The entry name is a flexible array member, and we don't know its size before * actually reading the entry. So we need a first copy to retrieve this size so * we can finally copy the whole struct. */ static int sqfs_read_entry(struct squashfs_directory_entry **dest, void *src) { struct squashfs_directory_entry *tmp; u16 sz; tmp = src; sz = get_unaligned_le16(src + sizeof(*tmp) - sizeof(u16)); /* * 'src' points to the begin of a directory entry, and 'sz' gets its * 'name_size' member's value. name_size is actually the string * length - 1, so adding 2 compensates this difference and adds space * for the trailling null byte. */ *dest = malloc(sizeof(*tmp) + sz + 2); if (!*dest) return -ENOMEM; memcpy(*dest, src, sizeof(*tmp) + sz + 1); (*dest)->name[sz + 1] = '\0'; return 0; } static int sqfs_get_tokens_length(char **tokens, int count) { int length = 0, i; /* * 1 is added to the result of strlen to consider the slash separator * between the tokens. */ for (i = 0; i < count; i++) length += strlen(tokens[i]) + 1; return length; } /* Takes a token list and returns a single string with '/' as separator. */ static char *sqfs_concat_tokens(char **token_list, int token_count) { char *result; int i, length = 0, offset = 0; length = sqfs_get_tokens_length(token_list, token_count); result = malloc(length + 1); if (!result) return NULL; result[length] = '\0'; for (i = 0; i < token_count; i++) { strcpy(result + offset, token_list[i]); offset += strlen(token_list[i]); result[offset++] = '/'; } return result; } /* * Differently from sqfs_concat_tokens, sqfs_join writes the result into a * previously allocated string, and returns the number of bytes written. */ static int sqfs_join(char **strings, char *dest, int start, int end, char separator) { int i, offset = 0; for (i = start; i < end; i++) { strcpy(dest + offset, strings[i]); offset += strlen(strings[i]); if (i < end - 1) dest[offset++] = separator; } return offset; } /* * Fills the given token list using its size (count) and a source string (str) */ static int sqfs_tokenize(char **tokens, int count, const char *str) { int i, j, ret = 0; char *aux, *strc; strc = strdup(str); if (!strc) return -ENOMEM; if (!strcmp(strc, "/")) { tokens[0] = strdup(strc); if (!tokens[0]) { ret = -ENOMEM; goto free_strc; } } else { for (j = 0; j < count; j++) { aux = strtok(!j ? strc : NULL, "/"); tokens[j] = strdup(aux); if (!tokens[j]) { for (i = 0; i < j; i++) free(tokens[i]); ret = -ENOMEM; goto free_strc; } } } free_strc: free(strc); return ret; } /* * Remove last 'updir + 1' tokens from the base path tokens list. This leaves us * with a token list containing only the tokens needed to form the resolved * path, and returns the decremented size of the token list. */ static int sqfs_clean_base_path(char **base, int count, int updir) { int i; for (i = count - updir - 1; i < count; i++) free(base[i]); return count - updir - 1; } /* * Given the base ("current dir.") path and the relative one, generate the * absolute path. */ static char *sqfs_get_abs_path(const char *base, const char *rel) { char **base_tokens, **rel_tokens, *resolved = NULL; int ret, bc, rc, i, updir = 0, resolved_size = 0, offset = 0; base_tokens = NULL; rel_tokens = NULL; /* Memory allocation for the token lists */ bc = sqfs_count_tokens(base); rc = sqfs_count_tokens(rel); if (bc < 1 || rc < 1) return NULL; base_tokens = calloc(bc, sizeof(char *)); if (!base_tokens) return NULL; rel_tokens = calloc(rc, sizeof(char *)); if (!rel_tokens) goto out; /* Fill token lists */ ret = sqfs_tokenize(base_tokens, bc, base); if (ret) goto out; ret = sqfs_tokenize(rel_tokens, rc, rel); if (ret) goto out; /* count '..' occurrences in target path */ for (i = 0; i < rc; i++) { if (!strcmp(rel_tokens[i], "..")) updir++; } /* Remove the last token and the '..' occurrences */ bc = sqfs_clean_base_path(base_tokens, bc, updir); if (bc < 0) goto out; /* Calculate resolved path size */ if (!bc) resolved_size++; resolved_size += sqfs_get_tokens_length(base_tokens, bc) + sqfs_get_tokens_length(rel_tokens, rc); resolved = malloc(resolved_size + 1); if (!resolved) goto out; /* Set resolved path */ memset(resolved, '\0', resolved_size + 1); offset += sqfs_join(base_tokens, resolved + offset, 0, bc, '/'); resolved[offset++] = '/'; offset += sqfs_join(rel_tokens, resolved + offset, updir, rc, '/'); out: if (rel_tokens) for (i = 0; i < rc; i++) free(rel_tokens[i]); if (base_tokens) for (i = 0; i < bc; i++) free(base_tokens[i]); free(rel_tokens); free(base_tokens); return resolved; } static char *sqfs_resolve_symlink(struct squashfs_symlink_inode *sym, const char *base_path) { char *resolved, *target; u32 sz; sz = get_unaligned_le32(&sym->symlink_size); target = malloc(sz + 1); if (!target) return NULL; /* * There is no trailling null byte in the symlink's target path, so a * copy is made and a '\0' is added at its end. */ target[sz] = '\0'; /* Get target name (relative path) */ strncpy(target, sym->symlink, sz); /* Relative -> absolute path conversion */ resolved = sqfs_get_abs_path(base_path, target); free(target); return resolved; } /* * m_list contains each metadata block's position, and m_count is the number of * elements of m_list. Those metadata blocks come from the compressed directory * table. */ static int sqfs_search_dir(struct squashfs_dir_stream *dirs, char **token_list, int token_count, u32 *m_list, int m_count) { struct squashfs_super_block *sblk = ctxt.sblk; char *path, *target, **sym_tokens, *res, *rem; int j, ret = 0, new_inode_number, offset; struct squashfs_symlink_inode *sym; struct squashfs_ldir_inode *ldir; struct squashfs_dir_inode *dir; struct fs_dir_stream *dirsp; struct fs_dirent *dent; unsigned char *table; res = NULL; rem = NULL; path = NULL; target = NULL; sym_tokens = NULL; dirsp = (struct fs_dir_stream *)dirs; /* Start by root inode */ table = sqfs_find_inode(dirs->inode_table, le32_to_cpu(sblk->inodes), sblk->inodes, sblk->block_size); dir = (struct squashfs_dir_inode *)table; ldir = (struct squashfs_ldir_inode *)table; /* get directory offset in directory table */ offset = sqfs_dir_offset(table, m_list, m_count); dirs->table = &dirs->dir_table[offset]; /* Setup directory header */ dirs->dir_header = malloc(SQFS_DIR_HEADER_SIZE); if (!dirs->dir_header) return -ENOMEM; memcpy(dirs->dir_header, dirs->table, SQFS_DIR_HEADER_SIZE); /* Initialize squashfs_dir_stream members */ dirs->table += SQFS_DIR_HEADER_SIZE; dirs->size = get_unaligned_le16(&dir->file_size) - SQFS_DIR_HEADER_SIZE; dirs->entry_count = dirs->dir_header->count + 1; /* No path given -> root directory */ if (!strcmp(token_list[0], "/")) { dirs->table = &dirs->dir_table[offset]; memcpy(&dirs->i_dir, dir, sizeof(*dir)); return 0; } for (j = 0; j < token_count; j++) { if (!sqfs_is_dir(get_unaligned_le16(&dir->inode_type))) { printf("** Cannot find directory. **\n"); ret = -EINVAL; goto out; } while (!sqfs_readdir(dirsp, &dent)) { ret = strcmp(dent->name, token_list[j]); if (!ret) break; free(dirs->entry); dirs->entry = NULL; } if (ret) { printf("** Cannot find directory. **\n"); ret = -EINVAL; goto out; } /* Redefine inode as the found token */ new_inode_number = dirs->entry->inode_offset + dirs->dir_header->inode_number; /* Get reference to inode in the inode table */ table = sqfs_find_inode(dirs->inode_table, new_inode_number, sblk->inodes, sblk->block_size); dir = (struct squashfs_dir_inode *)table; /* Check for symbolic link and inode type sanity */ if (get_unaligned_le16(&dir->inode_type) == SQFS_SYMLINK_TYPE) { sym = (struct squashfs_symlink_inode *)table; /* Get first j + 1 tokens */ path = sqfs_concat_tokens(token_list, j + 1); if (!path) { ret = -ENOMEM; goto out; } /* Resolve for these tokens */ target = sqfs_resolve_symlink(sym, path); if (!target) { ret = -ENOMEM; goto out; } /* Join remaining tokens */ rem = sqfs_concat_tokens(token_list + j + 1, token_count - j - 1); if (!rem) { ret = -ENOMEM; goto out; } /* Concatenate remaining tokens and symlink's target */ res = malloc(strlen(rem) + strlen(target) + 1); if (!res) { ret = -ENOMEM; goto out; } strcpy(res, target); res[strlen(target)] = '/'; strcpy(res + strlen(target) + 1, rem); token_count = sqfs_count_tokens(res); if (token_count < 0) { ret = -EINVAL; goto out; } sym_tokens = malloc(token_count * sizeof(char *)); if (!sym_tokens) { ret = -EINVAL; goto out; } /* Fill tokens list */ ret = sqfs_tokenize(sym_tokens, token_count, res); if (ret) { ret = -EINVAL; goto out; } free(dirs->entry); dirs->entry = NULL; ret = sqfs_search_dir(dirs, sym_tokens, token_count, m_list, m_count); goto out; } else if (!sqfs_is_dir(get_unaligned_le16(&dir->inode_type))) { printf("** Cannot find directory. **\n"); free(dirs->entry); dirs->entry = NULL; ret = -EINVAL; goto out; } /* Check if it is an extended dir. */ if (get_unaligned_le16(&dir->inode_type) == SQFS_LDIR_TYPE) ldir = (struct squashfs_ldir_inode *)table; /* Get dir. offset into the directory table */ offset = sqfs_dir_offset(table, m_list, m_count); dirs->table = &dirs->dir_table[offset]; /* Copy directory header */ memcpy(dirs->dir_header, &dirs->dir_table[offset], SQFS_DIR_HEADER_SIZE); /* Check for empty directory */ if (sqfs_is_empty_dir(table)) { printf("Empty directory.\n"); free(dirs->entry); dirs->entry = NULL; ret = SQFS_EMPTY_DIR; goto out; } dirs->table += SQFS_DIR_HEADER_SIZE; dirs->size = get_unaligned_le16(&dir->file_size); dirs->entry_count = dirs->dir_header->count + 1; dirs->size -= SQFS_DIR_HEADER_SIZE; free(dirs->entry); dirs->entry = NULL; } offset = sqfs_dir_offset(table, m_list, m_count); dirs->table = &dirs->dir_table[offset]; if (get_unaligned_le16(&dir->inode_type) == SQFS_DIR_TYPE) memcpy(&dirs->i_dir, dir, sizeof(*dir)); else memcpy(&dirs->i_ldir, ldir, sizeof(*ldir)); out: free(res); free(rem); free(path); free(target); free(sym_tokens); return ret; } /* * Inode and directory tables are stored as a series of metadata blocks, and * given the compressed size of this table, we can calculate how much metadata * blocks are needed to store the result of the decompression, since a * decompressed metadata block should have a size of 8KiB. */ static int sqfs_count_metablks(void *table, u32 offset, int table_size) { int count = 0, cur_size = 0, ret; u32 data_size; bool comp; do { ret = sqfs_read_metablock(table, offset + cur_size, &comp, &data_size); if (ret) return -EINVAL; cur_size += data_size + SQFS_HEADER_SIZE; count++; } while (cur_size < table_size); return count; } /* * Storing the metadata blocks header's positions will be useful while looking * for an entry in the directory table, using the reference (index and offset) * given by its inode. */ static int sqfs_get_metablk_pos(u32 *pos_list, void *table, u32 offset, int metablks_count) { u32 data_size, cur_size = 0; int j, ret = 0; bool comp; if (!metablks_count) return -EINVAL; for (j = 0; j < metablks_count; j++) { ret = sqfs_read_metablock(table, offset + cur_size, &comp, &data_size); if (ret) return -EINVAL; cur_size += data_size + SQFS_HEADER_SIZE; pos_list[j] = cur_size; } return ret; } static int sqfs_read_inode_table(unsigned char **inode_table) { struct squashfs_super_block *sblk = ctxt.sblk; u64 start, n_blks, table_offset, table_size; int j, ret = 0, metablks_count; unsigned char *src_table, *itb; u32 src_len, dest_offset = 0; unsigned long dest_len = 0; bool compressed; table_size = get_unaligned_le64(&sblk->directory_table_start) - get_unaligned_le64(&sblk->inode_table_start); start = get_unaligned_le64(&sblk->inode_table_start) / ctxt.cur_dev->blksz; n_blks = sqfs_calc_n_blks(sblk->inode_table_start, sblk->directory_table_start, &table_offset); /* Allocate a proper sized buffer (itb) to store the inode table */ itb = malloc_cache_aligned(n_blks * ctxt.cur_dev->blksz); if (!itb) return -ENOMEM; if (sqfs_disk_read(start, n_blks, itb) < 0) { ret = -EINVAL; goto free_itb; } /* Parse inode table (metadata block) header */ ret = sqfs_read_metablock(itb, table_offset, &compressed, &src_len); if (ret) { ret = -EINVAL; goto free_itb; } /* Calculate size to store the whole decompressed table */ metablks_count = sqfs_count_metablks(itb, table_offset, table_size); if (metablks_count < 1) { ret = -EINVAL; goto free_itb; } *inode_table = malloc(metablks_count * SQFS_METADATA_BLOCK_SIZE); if (!*inode_table) { ret = -ENOMEM; goto free_itb; } src_table = itb + table_offset + SQFS_HEADER_SIZE; /* Extract compressed Inode table */ for (j = 0; j < metablks_count; j++) { sqfs_read_metablock(itb, table_offset, &compressed, &src_len); if (compressed) { dest_len = SQFS_METADATA_BLOCK_SIZE; ret = sqfs_decompress(&ctxt, *inode_table + dest_offset, &dest_len, src_table, src_len); if (ret) { free(*inode_table); *inode_table = NULL; goto free_itb; } dest_offset += dest_len; } else { memcpy(*inode_table + (j * SQFS_METADATA_BLOCK_SIZE), src_table, src_len); } /* * Offsets to the decompression destination, to the metadata * buffer 'itb' and to the decompression source, respectively. */ table_offset += src_len + SQFS_HEADER_SIZE; src_table += src_len + SQFS_HEADER_SIZE; } free_itb: free(itb); return ret; } static int sqfs_read_directory_table(unsigned char **dir_table, u32 **pos_list) { u64 start, n_blks, table_offset, table_size; struct squashfs_super_block *sblk = ctxt.sblk; int j, ret = 0, metablks_count = -1; unsigned char *src_table, *dtb; u32 src_len, dest_offset = 0; unsigned long dest_len = 0; bool compressed; *dir_table = NULL; *pos_list = NULL; /* DIRECTORY TABLE */ table_size = get_unaligned_le64(&sblk->fragment_table_start) - get_unaligned_le64(&sblk->directory_table_start); start = get_unaligned_le64(&sblk->directory_table_start) / ctxt.cur_dev->blksz; n_blks = sqfs_calc_n_blks(sblk->directory_table_start, sblk->fragment_table_start, &table_offset); /* Allocate a proper sized buffer (dtb) to store the directory table */ dtb = malloc_cache_aligned(n_blks * ctxt.cur_dev->blksz); if (!dtb) return -ENOMEM; if (sqfs_disk_read(start, n_blks, dtb) < 0) goto out; /* Parse directory table (metadata block) header */ ret = sqfs_read_metablock(dtb, table_offset, &compressed, &src_len); if (ret) goto out; /* Calculate total size to store the whole decompressed table */ metablks_count = sqfs_count_metablks(dtb, table_offset, table_size); if (metablks_count < 1) goto out; *dir_table = malloc(metablks_count * SQFS_METADATA_BLOCK_SIZE); if (!*dir_table) goto out; *pos_list = malloc(metablks_count * sizeof(u32)); if (!*pos_list) goto out; ret = sqfs_get_metablk_pos(*pos_list, dtb, table_offset, metablks_count); if (ret) { metablks_count = -1; goto out; } src_table = dtb + table_offset + SQFS_HEADER_SIZE; /* Extract compressed Directory table */ dest_offset = 0; for (j = 0; j < metablks_count; j++) { sqfs_read_metablock(dtb, table_offset, &compressed, &src_len); if (compressed) { dest_len = SQFS_METADATA_BLOCK_SIZE; ret = sqfs_decompress(&ctxt, *dir_table + (j * SQFS_METADATA_BLOCK_SIZE), &dest_len, src_table, src_len); if (ret) { metablks_count = -1; goto out; } if (dest_len < SQFS_METADATA_BLOCK_SIZE) { dest_offset += dest_len; break; } dest_offset += dest_len; } else { memcpy(*dir_table + (j * SQFS_METADATA_BLOCK_SIZE), src_table, src_len); } /* * Offsets to the decompression destination, to the metadata * buffer 'dtb' and to the decompression source, respectively. */ table_offset += src_len + SQFS_HEADER_SIZE; src_table += src_len + SQFS_HEADER_SIZE; } out: if (metablks_count < 1) { free(*dir_table); free(*pos_list); *dir_table = NULL; *pos_list = NULL; } free(dtb); return metablks_count; } int sqfs_opendir(const char *filename, struct fs_dir_stream **dirsp) { unsigned char *inode_table = NULL, *dir_table = NULL; int j, token_count = 0, ret = 0, metablks_count; struct squashfs_dir_stream *dirs; char **token_list = NULL, *path = NULL; u32 *pos_list = NULL; dirs = calloc(1, sizeof(*dirs)); if (!dirs) return -EINVAL; /* these should be set to NULL to prevent dangling pointers */ dirs->dir_header = NULL; dirs->entry = NULL; dirs->table = NULL; dirs->inode_table = NULL; dirs->dir_table = NULL; ret = sqfs_read_inode_table(&inode_table); if (ret) { ret = -EINVAL; goto out; } metablks_count = sqfs_read_directory_table(&dir_table, &pos_list); if (metablks_count < 1) { ret = -EINVAL; goto out; } /* Tokenize filename */ token_count = sqfs_count_tokens(filename); if (token_count < 0) { ret = -EINVAL; goto out; } path = strdup(filename); if (!path) { ret = -EINVAL; goto out; } token_list = malloc(token_count * sizeof(char *)); if (!token_list) { ret = -EINVAL; goto out; } /* Fill tokens list */ ret = sqfs_tokenize(token_list, token_count, path); if (ret) goto out; /* * ldir's (extended directory) size is greater than dir, so it works as * a general solution for the malloc size, since 'i' is a union. */ dirs->inode_table = inode_table; dirs->dir_table = dir_table; ret = sqfs_search_dir(dirs, token_list, token_count, pos_list, metablks_count); if (ret) goto out; if (le16_to_cpu(dirs->i_dir.inode_type) == SQFS_DIR_TYPE) dirs->size = le16_to_cpu(dirs->i_dir.file_size); else dirs->size = le32_to_cpu(dirs->i_ldir.file_size); /* Setup directory header */ memcpy(dirs->dir_header, dirs->table, SQFS_DIR_HEADER_SIZE); dirs->entry_count = dirs->dir_header->count + 1; dirs->size -= SQFS_DIR_HEADER_SIZE; /* Setup entry */ dirs->entry = NULL; dirs->table += SQFS_DIR_HEADER_SIZE; *dirsp = (struct fs_dir_stream *)dirs; out: for (j = 0; j < token_count; j++) free(token_list[j]); free(token_list); free(pos_list); free(path); if (ret) { free(inode_table); free(dirs); } return ret; } int sqfs_readdir(struct fs_dir_stream *fs_dirs, struct fs_dirent **dentp) { struct squashfs_super_block *sblk = ctxt.sblk; struct squashfs_dir_stream *dirs; struct squashfs_lreg_inode *lreg; struct squashfs_base_inode *base; struct squashfs_reg_inode *reg; int i_number, offset = 0, ret; struct fs_dirent *dent; unsigned char *ipos; dirs = (struct squashfs_dir_stream *)fs_dirs; if (!dirs->size) { *dentp = NULL; return -SQFS_STOP_READDIR; } dent = &dirs->dentp; if (!dirs->entry_count) { if (dirs->size > SQFS_DIR_HEADER_SIZE) { dirs->size -= SQFS_DIR_HEADER_SIZE; } else { *dentp = NULL; dirs->size = 0; return -SQFS_STOP_READDIR; } if (dirs->size > SQFS_EMPTY_FILE_SIZE) { /* Read follow-up (emitted) dir. header */ memcpy(dirs->dir_header, dirs->table, SQFS_DIR_HEADER_SIZE); dirs->entry_count = dirs->dir_header->count + 1; ret = sqfs_read_entry(&dirs->entry, dirs->table + SQFS_DIR_HEADER_SIZE); if (ret) return -SQFS_STOP_READDIR; dirs->table += SQFS_DIR_HEADER_SIZE; } } else { ret = sqfs_read_entry(&dirs->entry, dirs->table); if (ret) return -SQFS_STOP_READDIR; } i_number = dirs->dir_header->inode_number + dirs->entry->inode_offset; ipos = sqfs_find_inode(dirs->inode_table, i_number, sblk->inodes, sblk->block_size); base = (struct squashfs_base_inode *)ipos; /* Set entry type and size */ switch (dirs->entry->type) { case SQFS_DIR_TYPE: case SQFS_LDIR_TYPE: dent->type = FS_DT_DIR; break; case SQFS_REG_TYPE: case SQFS_LREG_TYPE: /* * Entries do not differentiate extended from regular types, so * it needs to be verified manually. */ if (get_unaligned_le16(&base->inode_type) == SQFS_LREG_TYPE) { lreg = (struct squashfs_lreg_inode *)ipos; dent->size = get_unaligned_le64(&lreg->file_size); } else { reg = (struct squashfs_reg_inode *)ipos; dent->size = get_unaligned_le32(®->file_size); } dent->type = FS_DT_REG; break; case SQFS_BLKDEV_TYPE: case SQFS_CHRDEV_TYPE: case SQFS_LBLKDEV_TYPE: case SQFS_LCHRDEV_TYPE: case SQFS_FIFO_TYPE: case SQFS_SOCKET_TYPE: case SQFS_LFIFO_TYPE: case SQFS_LSOCKET_TYPE: dent->type = SQFS_MISC_ENTRY_TYPE; break; case SQFS_SYMLINK_TYPE: case SQFS_LSYMLINK_TYPE: dent->type = FS_DT_LNK; break; default: return -SQFS_STOP_READDIR; } /* Set entry name */ strncpy(dent->name, dirs->entry->name, dirs->entry->name_size + 1); dent->name[dirs->entry->name_size + 1] = '\0'; offset = dirs->entry->name_size + 1 + SQFS_ENTRY_BASE_LENGTH; dirs->entry_count--; /* Decrement size to be read */ if (dirs->size > offset) dirs->size -= offset; else dirs->size = 0; /* Keep a reference to the current entry before incrementing it */ dirs->table += offset; *dentp = dent; return 0; } int sqfs_probe(struct blk_desc *fs_dev_desc, struct disk_partition *fs_partition) { struct squashfs_super_block *sblk; int ret; ctxt.cur_dev = fs_dev_desc; ctxt.cur_part_info = *fs_partition; ret = sqfs_read_sblk(&sblk); if (ret) goto error; /* Make sure it has a valid SquashFS magic number*/ if (get_unaligned_le32(&sblk->s_magic) != SQFS_MAGIC_NUMBER) { debug("Bad magic number for SquashFS image.\n"); ret = -EINVAL; goto error; } ctxt.sblk = sblk; ret = sqfs_decompressor_init(&ctxt); if (ret) { goto error; } return 0; error: ctxt.cur_dev = NULL; free(ctxt.sblk); ctxt.sblk = NULL; return ret; } static char *sqfs_basename(char *path) { char *fname; fname = path + strlen(path) - 1; while (fname >= path) { if (*fname == '/') { fname++; break; } fname--; } return fname; } static char *sqfs_dirname(char *path) { char *fname; fname = sqfs_basename(path); --fname; *fname = '\0'; return path; } /* * Takes a path to file and splits it in two parts: the filename itself and the * directory's path, e.g.: * path: /path/to/file.txt * file: file.txt * dir: /path/to */ static int sqfs_split_path(char **file, char **dir, const char *path) { char *dirc, *basec, *bname, *dname, *tmp_path; int ret = 0; *file = NULL; *dir = NULL; dirc = NULL; basec = NULL; bname = NULL; dname = NULL; tmp_path = NULL; /* check for first slash in path*/ if (path[0] == '/') { tmp_path = strdup(path); if (!tmp_path) { ret = -ENOMEM; goto out; } } else { tmp_path = malloc(strlen(path) + 2); if (!tmp_path) { ret = -ENOMEM; goto out; } tmp_path[0] = '/'; strcpy(tmp_path + 1, path); } /* String duplicates */ dirc = strdup(tmp_path); if (!dirc) { ret = -ENOMEM; goto out; } basec = strdup(tmp_path); if (!basec) { ret = -ENOMEM; goto out; } dname = sqfs_dirname(dirc); bname = sqfs_basename(basec); *file = strdup(bname); if (!*file) { ret = -ENOMEM; goto out; } if (*dname == '\0') { *dir = malloc(2); if (!*dir) { ret = -ENOMEM; goto out; } (*dir)[0] = '/'; (*dir)[1] = '\0'; } else { *dir = strdup(dname); if (!*dir) { ret = -ENOMEM; goto out; } } out: if (ret) { free(*file); free(*dir); *dir = NULL; *file = NULL; } free(basec); free(dirc); free(tmp_path); return ret; } static int sqfs_get_regfile_info(struct squashfs_reg_inode *reg, struct squashfs_file_info *finfo, struct squashfs_fragment_block_entry *fentry, __le32 blksz) { int datablk_count = 0, ret; finfo->size = get_unaligned_le32(®->file_size); finfo->offset = get_unaligned_le32(®->offset); finfo->start = get_unaligned_le32(®->start_block); finfo->frag = SQFS_IS_FRAGMENTED(get_unaligned_le32(®->fragment)); if (finfo->frag && finfo->offset == 0xFFFFFFFF) return -EINVAL; if (finfo->size < 1 || finfo->start == 0xFFFFFFFF) return -EINVAL; if (finfo->frag) { datablk_count = finfo->size / le32_to_cpu(blksz); ret = sqfs_frag_lookup(get_unaligned_le32(®->fragment), fentry); if (ret < 0) return -EINVAL; finfo->comp = ret; if (fentry->size < 1 || fentry->start == 0x7FFFFFFF) return -EINVAL; } else { datablk_count = DIV_ROUND_UP(finfo->size, le32_to_cpu(blksz)); } finfo->blk_sizes = malloc(datablk_count * sizeof(u32)); if (!finfo->blk_sizes) return -ENOMEM; return datablk_count; } static int sqfs_get_lregfile_info(struct squashfs_lreg_inode *lreg, struct squashfs_file_info *finfo, struct squashfs_fragment_block_entry *fentry, __le32 blksz) { int datablk_count = 0, ret; finfo->size = get_unaligned_le64(&lreg->file_size); finfo->offset = get_unaligned_le32(&lreg->offset); finfo->start = get_unaligned_le64(&lreg->start_block); finfo->frag = SQFS_IS_FRAGMENTED(get_unaligned_le32(&lreg->fragment)); if (finfo->frag && finfo->offset == 0xFFFFFFFF) return -EINVAL; if (finfo->size < 1 || finfo->start == 0x7FFFFFFF) return -EINVAL; if (finfo->frag) { datablk_count = finfo->size / le32_to_cpu(blksz); ret = sqfs_frag_lookup(get_unaligned_le32(&lreg->fragment), fentry); if (ret < 0) return -EINVAL; finfo->comp = ret; if (fentry->size < 1 || fentry->start == 0x7FFFFFFF) return -EINVAL; } else { datablk_count = DIV_ROUND_UP(finfo->size, le32_to_cpu(blksz)); } finfo->blk_sizes = malloc(datablk_count * sizeof(u32)); if (!finfo->blk_sizes) return -ENOMEM; return datablk_count; } int sqfs_read(const char *filename, void *buf, loff_t offset, loff_t len, loff_t *actread) { char *dir = NULL, *fragment_block, *datablock = NULL, *data_buffer = NULL; char *fragment = NULL, *file = NULL, *resolved, *data; u64 start, n_blks, table_size, data_offset, table_offset, sparse_size; int ret, j, i_number, datablk_count = 0; struct squashfs_super_block *sblk = ctxt.sblk; struct squashfs_fragment_block_entry frag_entry; struct squashfs_file_info finfo = {0}; struct squashfs_symlink_inode *symlink; struct fs_dir_stream *dirsp = NULL; struct squashfs_dir_stream *dirs; struct squashfs_lreg_inode *lreg; struct squashfs_base_inode *base; struct squashfs_reg_inode *reg; unsigned long dest_len; struct fs_dirent *dent; unsigned char *ipos; *actread = 0; if (offset) { /* * TODO: implement reading at an offset in file */ printf("Error: reading at a specific offset in a squashfs file is not supported yet.\n"); return -EINVAL; } /* * sqfs_opendir will uncompress inode and directory tables, and will * return a pointer to the directory that contains the requested file. */ sqfs_split_path(&file, &dir, filename); ret = sqfs_opendir(dir, &dirsp); if (ret) { goto out; } dirs = (struct squashfs_dir_stream *)dirsp; /* For now, only regular files are able to be loaded */ while (!sqfs_readdir(dirsp, &dent)) { ret = strcmp(dent->name, file); if (!ret) break; free(dirs->entry); dirs->entry = NULL; } if (ret) { printf("File not found.\n"); *actread = 0; ret = -ENOENT; goto out; } i_number = dirs->dir_header->inode_number + dirs->entry->inode_offset; ipos = sqfs_find_inode(dirs->inode_table, i_number, sblk->inodes, sblk->block_size); base = (struct squashfs_base_inode *)ipos; switch (get_unaligned_le16(&base->inode_type)) { case SQFS_REG_TYPE: reg = (struct squashfs_reg_inode *)ipos; datablk_count = sqfs_get_regfile_info(reg, &finfo, &frag_entry, sblk->block_size); if (datablk_count < 0) { ret = -EINVAL; goto out; } memcpy(finfo.blk_sizes, ipos + sizeof(*reg), datablk_count * sizeof(u32)); break; case SQFS_LREG_TYPE: lreg = (struct squashfs_lreg_inode *)ipos; datablk_count = sqfs_get_lregfile_info(lreg, &finfo, &frag_entry, sblk->block_size); if (datablk_count < 0) { ret = -EINVAL; goto out; } memcpy(finfo.blk_sizes, ipos + sizeof(*lreg), datablk_count * sizeof(u32)); break; case SQFS_SYMLINK_TYPE: case SQFS_LSYMLINK_TYPE: symlink = (struct squashfs_symlink_inode *)ipos; resolved = sqfs_resolve_symlink(symlink, filename); ret = sqfs_read(resolved, buf, offset, len, actread); free(resolved); goto out; case SQFS_BLKDEV_TYPE: case SQFS_CHRDEV_TYPE: case SQFS_LBLKDEV_TYPE: case SQFS_LCHRDEV_TYPE: case SQFS_FIFO_TYPE: case SQFS_SOCKET_TYPE: case SQFS_LFIFO_TYPE: case SQFS_LSOCKET_TYPE: default: printf("Unsupported entry type\n"); ret = -EINVAL; goto out; } /* If the user specifies a length, check its sanity */ if (len) { if (len > finfo.size) { ret = -EINVAL; goto out; } finfo.size = len; } else { len = finfo.size; } if (datablk_count) { data_offset = finfo.start; datablock = malloc(get_unaligned_le32(&sblk->block_size)); if (!datablock) { ret = -ENOMEM; goto out; } } for (j = 0; j < datablk_count; j++) { start = data_offset / ctxt.cur_dev->blksz; table_size = SQFS_BLOCK_SIZE(finfo.blk_sizes[j]); table_offset = data_offset - (start * ctxt.cur_dev->blksz); n_blks = DIV_ROUND_UP(table_size + table_offset, ctxt.cur_dev->blksz); /* Don't load any data for sparse blocks */ if (finfo.blk_sizes[j] == 0) { n_blks = 0; table_offset = 0; data_buffer = NULL; data = NULL; } else { data_buffer = malloc_cache_aligned(n_blks * ctxt.cur_dev->blksz); if (!data_buffer) { ret = -ENOMEM; goto out; } ret = sqfs_disk_read(start, n_blks, data_buffer); if (ret < 0) { /* * Possible causes: too many data blocks or too large * SquashFS block size. Tip: re-compile the SquashFS * image with mksquashfs's -b option. */ printf("Error: too many data blocks to be read.\n"); goto out; } data = data_buffer + table_offset; } /* Load the data */ if (finfo.blk_sizes[j] == 0) { /* This is a sparse block */ sparse_size = get_unaligned_le32(&sblk->block_size); if ((*actread + sparse_size) > len) sparse_size = len - *actread; memset(buf + *actread, 0, sparse_size); *actread += sparse_size; } else if (SQFS_COMPRESSED_BLOCK(finfo.blk_sizes[j])) { dest_len = get_unaligned_le32(&sblk->block_size); ret = sqfs_decompress(&ctxt, datablock, &dest_len, data, table_size); if (ret) goto out; if ((*actread + dest_len) > len) dest_len = len - *actread; memcpy(buf + *actread, datablock, dest_len); *actread += dest_len; } else { if ((*actread + table_size) > len) table_size = len - *actread; memcpy(buf + *actread, data, table_size); *actread += table_size; } data_offset += table_size; if (data_buffer) free(data_buffer); data_buffer = NULL; if (*actread >= len) break; } /* * There is no need to continue if the file is not fragmented. */ if (!finfo.frag) { ret = 0; goto out; } start = frag_entry.start / ctxt.cur_dev->blksz; table_size = SQFS_BLOCK_SIZE(frag_entry.size); table_offset = frag_entry.start - (start * ctxt.cur_dev->blksz); n_blks = DIV_ROUND_UP(table_size + table_offset, ctxt.cur_dev->blksz); fragment = malloc_cache_aligned(n_blks * ctxt.cur_dev->blksz); if (!fragment) { ret = -ENOMEM; goto out; } ret = sqfs_disk_read(start, n_blks, fragment); if (ret < 0) goto out; /* File compressed and fragmented */ if (finfo.frag && finfo.comp) { dest_len = get_unaligned_le32(&sblk->block_size); fragment_block = malloc(dest_len); if (!fragment_block) { ret = -ENOMEM; goto out; } ret = sqfs_decompress(&ctxt, fragment_block, &dest_len, (void *)fragment + table_offset, frag_entry.size); if (ret) { free(fragment_block); goto out; } memcpy(buf + *actread, &fragment_block[finfo.offset], finfo.size - *actread); *actread = finfo.size; free(fragment_block); } else if (finfo.frag && !finfo.comp) { fragment_block = (void *)fragment + table_offset; memcpy(buf + *actread, &fragment_block[finfo.offset], finfo.size - *actread); *actread = finfo.size; } out: free(fragment); if (datablk_count) { free(data_buffer); free(datablock); } free(file); free(dir); free(finfo.blk_sizes); sqfs_closedir(dirsp); return ret; } int sqfs_size(const char *filename, loff_t *size) { struct squashfs_super_block *sblk = ctxt.sblk; struct squashfs_symlink_inode *symlink; struct fs_dir_stream *dirsp = NULL; struct squashfs_base_inode *base; struct squashfs_dir_stream *dirs; struct squashfs_lreg_inode *lreg; struct squashfs_reg_inode *reg; char *dir, *file, *resolved; struct fs_dirent *dent; unsigned char *ipos; int ret, i_number; sqfs_split_path(&file, &dir, filename); /* * sqfs_opendir will uncompress inode and directory tables, and will * return a pointer to the directory that contains the requested file. */ ret = sqfs_opendir(dir, &dirsp); if (ret) { ret = -EINVAL; goto free_strings; } dirs = (struct squashfs_dir_stream *)dirsp; while (!sqfs_readdir(dirsp, &dent)) { ret = strcmp(dent->name, file); if (!ret) break; free(dirs->entry); dirs->entry = NULL; } if (ret) { printf("File not found.\n"); *size = 0; ret = -EINVAL; goto free_strings; } i_number = dirs->dir_header->inode_number + dirs->entry->inode_offset; ipos = sqfs_find_inode(dirs->inode_table, i_number, sblk->inodes, sblk->block_size); free(dirs->entry); dirs->entry = NULL; base = (struct squashfs_base_inode *)ipos; switch (get_unaligned_le16(&base->inode_type)) { case SQFS_REG_TYPE: reg = (struct squashfs_reg_inode *)ipos; *size = get_unaligned_le32(®->file_size); break; case SQFS_LREG_TYPE: lreg = (struct squashfs_lreg_inode *)ipos; *size = get_unaligned_le64(&lreg->file_size); break; case SQFS_SYMLINK_TYPE: case SQFS_LSYMLINK_TYPE: symlink = (struct squashfs_symlink_inode *)ipos; resolved = sqfs_resolve_symlink(symlink, filename); ret = sqfs_size(resolved, size); free(resolved); break; case SQFS_BLKDEV_TYPE: case SQFS_CHRDEV_TYPE: case SQFS_LBLKDEV_TYPE: case SQFS_LCHRDEV_TYPE: case SQFS_FIFO_TYPE: case SQFS_SOCKET_TYPE: case SQFS_LFIFO_TYPE: case SQFS_LSOCKET_TYPE: default: printf("Unable to recover entry's size.\n"); *size = 0; ret = -EINVAL; break; } free_strings: free(dir); free(file); sqfs_closedir(dirsp); return ret; } int sqfs_exists(const char *filename) { struct fs_dir_stream *dirsp = NULL; struct squashfs_dir_stream *dirs; char *dir, *file; struct fs_dirent *dent; int ret; sqfs_split_path(&file, &dir, filename); /* * sqfs_opendir will uncompress inode and directory tables, and will * return a pointer to the directory that contains the requested file. */ ret = sqfs_opendir(dir, &dirsp); if (ret) { ret = -EINVAL; goto free_strings; } dirs = (struct squashfs_dir_stream *)dirsp; while (!sqfs_readdir(dirsp, &dent)) { ret = strcmp(dent->name, file); if (!ret) break; free(dirs->entry); dirs->entry = NULL; } sqfs_closedir(dirsp); free_strings: free(dir); free(file); return ret == 0; } void sqfs_close(void) { sqfs_decompressor_cleanup(&ctxt); free(ctxt.sblk); ctxt.sblk = NULL; ctxt.cur_dev = NULL; } void sqfs_closedir(struct fs_dir_stream *dirs) { struct squashfs_dir_stream *sqfs_dirs; if (!dirs) return; sqfs_dirs = (struct squashfs_dir_stream *)dirs; free(sqfs_dirs->inode_table); free(sqfs_dirs->dir_table); free(sqfs_dirs->dir_header); free(sqfs_dirs); }