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