diff options
Diffstat (limited to 'fs/squashfs/sqfs.c')
| -rw-r--r-- | fs/squashfs/sqfs.c | 1538 |
1 files changed, 1538 insertions, 0 deletions
diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c new file mode 100644 index 0000000000..340e5ebdb9 --- /dev/null +++ b/fs/squashfs/sqfs.c @@ -0,0 +1,1538 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2020 Bootlin + * + * Author: Joao Marcos Costa <joaomarcos.costa@bootlin.com> + * + * sqfs.c: SquashFS filesystem implementation + */ + +#include <asm/unaligned.h> +#include <errno.h> +#include <fs.h> +#include <linux/types.h> +#include <linux/byteorder/little_endian.h> +#include <linux/byteorder/generic.h> +#include <memalign.h> +#include <stdlib.h> +#include <string.h> +#include <squashfs.h> +#include <part.h> + +#include "sqfs_decompressor.h" +#include "sqfs_filesystem.h" +#include "sqfs_utils.h" + +struct squashfs_ctxt { + struct disk_partition cur_part_info; + struct blk_desc *cur_dev; + struct squashfs_super_block *sblk; +}; + +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); + 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, comp_type; + + comp_type = get_unaligned_le16(&sblk->compression); + + 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) + return -ENOMEM; + + if (sqfs_disk_read(start, n_blks, table) < 0) { + free(table); + return -EINVAL; + } + + 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 free_table; + } + + if (sqfs_disk_read(start, n_blks, metadata_buffer) < 0) { + ret = -EINVAL; + goto free_buffer; + } + + /* 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; + + entries = malloc(SQFS_METADATA_BLOCK_SIZE); + if (!entries) { + ret = -ENOMEM; + goto free_buffer; + } + + if (SQFS_COMPRESSED_METADATA(header)) { + src_len = SQFS_METADATA_SIZE(header); + dest_len = SQFS_METADATA_BLOCK_SIZE; + ret = sqfs_decompress(comp_type, entries, &dest_len, metadata, + src_len); + if (ret) { + ret = -EINVAL; + goto free_entries; + } + } else { + memcpy(entries, metadata, SQFS_METADATA_SIZE(header)); + } + + *e = entries[offset]; + ret = SQFS_COMPRESSED_BLOCK(e->size); + +free_entries: + free(entries); +free_buffer: + free(metadata_buffer); +free_table: + 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); + 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) +{ + char *aux, *strc; + int i, j; + + strc = strdup(str); + if (!strc) + return -ENOMEM; + + if (!strcmp(strc, "/")) { + tokens[0] = strdup(strc); + if (!tokens[0]) { + free(strc); + return -ENOMEM; + } + } 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]); + free(strc); + return -ENOMEM; + } + } + } + + free(strc); + + return 0; +} + +/* + * 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; + + /* 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 = malloc(bc * sizeof(char *)); + if (!base_tokens) + return NULL; + + rel_tokens = malloc(rc * sizeof(char *)); + if (!rel_tokens) + goto free_b_tokens; + + /* Fill token lists */ + ret = sqfs_tokenize(base_tokens, bc, base); + if (ret) + goto free_r_tokens; + + sqfs_tokenize(rel_tokens, rc, rel); + if (ret) + goto free_r_tokens; + + /* 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 free_r_tokens; + + /* 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 free_r_tokens_loop; + + /* 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, '/'); + +free_r_tokens_loop: + for (i = 0; i < rc; i++) + free(rel_tokens[i]); + for (i = 0; i < bc; i++) + free(base_tokens[i]); +free_r_tokens: + free(rel_tokens); +free_b_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, 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; + + 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); + + /* root is a regular directory, not an extended one */ + dir = (struct squashfs_dir_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"); + return -EINVAL; + } + + while (!sqfs_readdir(dirsp, &dent)) { + ret = strcmp(dent->name, token_list[j]); + if (!ret) + break; + free(dirs->entry); + } + + if (ret) { + printf("** Cannot find directory. **\n"); + return -EINVAL; + } + + /* 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); + /* Resolve for these tokens */ + target = sqfs_resolve_symlink(sym, path); + /* Join remaining tokens */ + rem = sqfs_concat_tokens(token_list + j + 1, token_count - + j - 1); + /* Concatenate remaining tokens and symlink's target */ + res = malloc(strlen(rem) + strlen(target) + 1); + strcpy(res, target); + res[strlen(target)] = '/'; + strcpy(res + strlen(target) + 1, rem); + token_count = sqfs_count_tokens(res); + + if (token_count < 0) + return -EINVAL; + + sym_tokens = malloc(token_count * sizeof(char *)); + if (!sym_tokens) + return -EINVAL; + + /* Fill tokens list */ + ret = sqfs_tokenize(sym_tokens, token_count, res); + if (ret) + return -EINVAL; + free(dirs->entry); + + ret = sqfs_search_dir(dirs, sym_tokens, token_count, + m_list, m_count); + return ret; + } else if (!sqfs_is_dir(get_unaligned_le16(&dir->inode_type))) { + printf("** Cannot find directory. **\n"); + free(dirs->entry); + return -EINVAL; + } + + /* 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); + return SQFS_EMPTY_DIR; + } + + 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); + } + + 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)); + + return 0; +} + +/* + * 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, comp_type; + unsigned char *src_table, *itb; + u32 src_len, dest_offset = 0; + unsigned long dest_len; + bool compressed; + + comp_type = get_unaligned_le16(&sblk->compression); + 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(comp_type, *inode_table + + dest_offset, &dest_len, + src_table, src_len); + if (ret) { + free(*inode_table); + goto free_itb; + } + + } 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. + */ + dest_offset += dest_len; + 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; + int j, ret = 0, metablks_count = -1, comp_type; + struct squashfs_super_block *sblk = ctxt.sblk; + unsigned char *src_table, *dtb; + u32 src_len, dest_offset = 0; + unsigned long dest_len; + bool compressed; + + comp_type = get_unaligned_le16(&sblk->compression); + + /* 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 free_dtb; + + /* Parse directory table (metadata block) header */ + ret = sqfs_read_metablock(dtb, table_offset, &compressed, &src_len); + if (ret) + goto free_dtb; + + /* Calculate total size to store the whole decompressed table */ + metablks_count = sqfs_count_metablks(dtb, table_offset, table_size); + if (metablks_count < 1) + goto free_dtb; + + *dir_table = malloc(metablks_count * SQFS_METADATA_BLOCK_SIZE); + if (!*dir_table) + goto free_dtb; + + *pos_list = malloc(metablks_count * sizeof(u32)); + if (!*pos_list) { + free(*dir_table); + goto free_dtb; + } + + ret = sqfs_get_metablk_pos(*pos_list, dtb, table_offset, + metablks_count); + if (ret) { + metablks_count = -1; + free(*dir_table); + free(*pos_list); + goto free_dtb; + } + + 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(comp_type, *dir_table + + (j * SQFS_METADATA_BLOCK_SIZE), + &dest_len, src_table, src_len); + if (ret) { + metablks_count = -1; + free(*dir_table); + goto free_dtb; + } + + if (dest_len < SQFS_METADATA_BLOCK_SIZE) { + dest_offset += dest_len; + break; + } + } 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. + */ + dest_offset += dest_len; + table_offset += src_len + SQFS_HEADER_SIZE; + src_table += src_len + SQFS_HEADER_SIZE; + } + +free_dtb: + 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, ret = 0, metablks_count; + struct squashfs_dir_stream *dirs; + char **token_list, *path; + u32 *pos_list = NULL; + + dirs = malloc(sizeof(*dirs)); + if (!dirs) + return -EINVAL; + + ret = sqfs_read_inode_table(&inode_table); + if (ret) + return -EINVAL; + + metablks_count = sqfs_read_directory_table(&dir_table, &pos_list); + if (metablks_count < 1) + return -EINVAL; + + /* Tokenize filename */ + token_count = sqfs_count_tokens(filename); + if (token_count < 0) + return -EINVAL; + + path = strdup(filename); + if (!path) + return -ENOMEM; + + token_list = malloc(token_count * sizeof(char *)); + if (!token_list) { + ret = -EINVAL; + goto free_path; + } + + /* Fill tokens list */ + ret = sqfs_tokenize(token_list, token_count, path); + if (ret) + goto free_tokens; + /* + * 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 free_tokens; + + 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; + +free_tokens: + for (j = 0; j < token_count; j++) + free(token_list[j]); + free(token_list); + free(pos_list); +free_path: + free(path); + + 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) + return ret; + + /* Make sure it has a valid SquashFS magic number*/ + if (get_unaligned_le32(&sblk->s_magic) != SQFS_MAGIC_NUMBER) { + printf("Bad magic number for SquashFS image.\n"); + ctxt.cur_dev = NULL; + return -EINVAL; + } + + ctxt.sblk = sblk; + + return 0; +} + +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; + + /* check for first slash in path*/ + if (path[0] == '/') { + tmp_path = strdup(path); + if (!tmp_path) + return -ENOMEM; + } else { + tmp_path = malloc(strlen(path) + 2); + if (!tmp_path) + return -ENOMEM; + tmp_path[0] = '/'; + strcpy(tmp_path + 1, path); + } + + /* String duplicates */ + dirc = strdup(tmp_path); + if (!dirc) { + ret = -ENOMEM; + goto free_tmp; + } + + basec = strdup(tmp_path); + if (!basec) { + ret = -ENOMEM; + goto free_dirc; + } + + dname = sqfs_dirname(dirc); + bname = sqfs_basename(basec); + + *file = strdup(bname); + + if (!*file) { + ret = -ENOMEM; + goto free_basec; + } + + if (*dname == '\0') { + *dir = malloc(2); + if (!*dir) { + ret = -ENOMEM; + goto free_basec; + } + + (*dir)[0] = '/'; + (*dir)[1] = '\0'; + } else { + *dir = strdup(dname); + if (!*dir) { + ret = -ENOMEM; + goto free_basec; + } + } + +free_basec: + free(basec); +free_dirc: + free(dirc); +free_tmp: + 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) { + datablk_count = finfo->size / le32_to_cpu(blksz); + ret = sqfs_frag_lookup(get_unaligned_le32(®->fragment), + fentry); + if (ret < 0) + return -EINVAL; + finfo->comp = true; + } 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) { + 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 = true; + } 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, *fragment_block, *datablock = NULL, *data_buffer = NULL; + char *fragment, *file, *resolved, *data; + u64 start, n_blks, table_size, data_offset, table_offset; + int ret, j, i_number, comp_type, 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; + + comp_type = get_unaligned_le16(&sblk->compression); + + /* + * 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) { + sqfs_closedir(dirsp); + goto free_paths; + } + + 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); + } + + if (ret) { + printf("File not found.\n"); + *actread = 0; + sqfs_closedir(dirsp); + ret = -ENOENT; + goto free_paths; + } + + 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 free_paths; + } + + 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 free_paths; + } + + 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 free_paths; + 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 free_paths; + } + + /* If the user specifies a length, check its sanity */ + if (len) { + if (len > finfo.size) { + ret = -EINVAL; + goto free_paths; + } + + finfo.size = len; + } + + if (datablk_count) { + data_offset = finfo.start; + datablock = malloc(get_unaligned_le32(&sblk->block_size)); + if (!datablock) { + ret = -ENOMEM; + goto free_paths; + } + } + + 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); + + data_buffer = malloc_cache_aligned(n_blks * ctxt.cur_dev->blksz); + + if (!data_buffer) { + ret = -ENOMEM; + goto free_datablk; + } + + 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 <block_size> option. + */ + printf("Error: too many data blocks to be read.\n"); + goto free_buffer; + } + + data = data_buffer + table_offset; + + /* Load the data */ + if (SQFS_COMPRESSED_BLOCK(finfo.blk_sizes[j])) { + dest_len = get_unaligned_le32(&sblk->block_size); + ret = sqfs_decompress(comp_type, datablock, &dest_len, + data, table_size); + if (ret) + goto free_buffer; + + memcpy(buf + offset + *actread, datablock, dest_len); + *actread += dest_len; + } else { + memcpy(buf + offset + *actread, data, table_size); + *actread += table_size; + } + + data_offset += table_size; + } + + free(finfo.blk_sizes); + + /* + * There is no need to continue if the file is not fragmented. + */ + if (!finfo.frag) { + ret = 0; + goto free_buffer; + } + + 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 free_buffer; + } + + ret = sqfs_disk_read(start, n_blks, fragment); + if (ret < 0) + goto free_fragment; + + /* 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 free_fragment; + } + + ret = sqfs_decompress(comp_type, fragment_block, &dest_len, + (void *)fragment + table_offset, + frag_entry.size); + if (ret) { + free(fragment_block); + goto free_fragment; + } + + for (j = offset + *actread; j < finfo.size; j++) { + memcpy(buf + j, &fragment_block[finfo.offset + j], 1); + (*actread)++; + } + + free(fragment_block); + + } else if (finfo.frag && !finfo.comp) { + fragment_block = (void *)fragment + table_offset; + + for (j = offset + *actread; j < finfo.size; j++) { + memcpy(buf + j, &fragment_block[finfo.offset + j], 1); + (*actread)++; + } + } + +free_fragment: + free(fragment); +free_buffer: + if (datablk_count) + free(data_buffer); +free_datablk: + if (datablk_count) + free(datablock); +free_paths: + free(file); + free(dir); + + 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) { + sqfs_closedir(dirsp); + 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); + } + + 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); + + 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; +} + +void sqfs_close(void) +{ + free(ctxt.sblk); + ctxt.cur_dev = NULL; +} + +void sqfs_closedir(struct fs_dir_stream *dirs) +{ + struct squashfs_dir_stream *sqfs_dirs; + + sqfs_dirs = (struct squashfs_dir_stream *)dirs; + free(sqfs_dirs->inode_table); + free(sqfs_dirs->dir_table); + free(sqfs_dirs->dir_header); +} |