1/* 2 * Copyright (C) 2015 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#include "squashfs_utils.h" 18 19#include <cutils/fs.h> 20#include <cutils/klog.h> 21#include <errno.h> 22#include <fcntl.h> 23#include <stdlib.h> 24#include <string.h> 25#include <unistd.h> 26 27#include "squashfs_fs.h" 28 29#ifdef SQUASHFS_NO_KLOG 30#include <stdio.h> 31#define ERROR(x...) fprintf(stderr, x) 32#else 33#define ERROR(x...) KLOG_ERROR("squashfs_utils", x) 34#endif 35 36size_t squashfs_get_sb_size() 37{ 38 return sizeof(struct squashfs_super_block); 39} 40 41int squashfs_parse_sb_buffer(const void *buf, struct squashfs_info *info) 42{ 43 const struct squashfs_super_block *sb = 44 (const struct squashfs_super_block *)buf; 45 46 if (sb->s_magic != SQUASHFS_MAGIC) { 47 return -1; 48 } 49 50 info->block_size = sb->block_size; 51 info->inodes = sb->inodes; 52 info->bytes_used = sb->bytes_used; 53 // by default mksquashfs pads the filesystem to 4K blocks 54 info->bytes_used_4K_padded = 55 sb->bytes_used + (4096 - (sb->bytes_used & (4096 - 1))); 56 57 return 0; 58} 59 60int squashfs_parse_sb(const char *blk_device, struct squashfs_info *info) 61{ 62 int ret = 0; 63 struct squashfs_super_block sb; 64 int data_device; 65 66 data_device = TEMP_FAILURE_RETRY(open(blk_device, O_RDONLY | O_CLOEXEC)); 67 if (data_device == -1) { 68 ERROR("Error opening block device (%s)\n", strerror(errno)); 69 return -1; 70 } 71 72 if (TEMP_FAILURE_RETRY(read(data_device, &sb, sizeof(sb))) 73 != sizeof(sb)) { 74 ERROR("Error reading superblock\n"); 75 ret = -1; 76 goto cleanup; 77 } 78 79 if (squashfs_parse_sb_buffer(&sb, info) == -1) { 80 ERROR("Not a valid squashfs filesystem\n"); 81 ret = -1; 82 goto cleanup; 83 } 84 85cleanup: 86 close(data_device); 87 return ret; 88} 89