1/*
2 * Copyright (C) 2012 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 <stdio.h>
18#include <stdlib.h>
19#include <fcntl.h>
20#include <unistd.h>
21#include <errno.h>
22#include <string.h>
23#include <dirent.h>
24#include <errno.h>
25#include <fcntl.h>
26#include <vector>
27#include <string>
28
29#include <sys/types.h>
30#include <sys/stat.h>
31#include <sys/types.h>
32#include <sys/mman.h>
33#include <sys/mount.h>
34#include <sys/wait.h>
35
36#include <linux/kdev_t.h>
37
38#define LOG_TAG "Vold"
39
40#include <base/logging.h>
41#include <base/stringprintf.h>
42#include <cutils/log.h>
43#include <cutils/properties.h>
44#include <logwrap/logwrap.h>
45#include <selinux/selinux.h>
46
47#include "Ext4.h"
48#include "Utils.h"
49#include "VoldUtil.h"
50
51using android::base::StringPrintf;
52
53namespace android {
54namespace vold {
55namespace ext4 {
56
57static const char* kResizefsPath = "/system/bin/resize2fs";
58static const char* kMkfsPath = "/system/bin/make_ext4fs";
59static const char* kFsckPath = "/system/bin/e2fsck";
60
61bool IsSupported() {
62    return access(kMkfsPath, X_OK) == 0
63            && access(kFsckPath, X_OK) == 0
64            && IsFilesystemSupported("ext4");
65}
66
67status_t Check(const std::string& source, const std::string& target) {
68    // The following is shamelessly borrowed from fs_mgr.c, so it should be
69    // kept in sync with any changes over there.
70
71    const char* c_source = source.c_str();
72    const char* c_target = target.c_str();
73
74    int status;
75    int ret;
76    long tmpmnt_flags = MS_NOATIME | MS_NOEXEC | MS_NOSUID;
77    char *tmpmnt_opts = (char*) "nomblk_io_submit,errors=remount-ro";
78
79    /*
80     * First try to mount and unmount the filesystem.  We do this because
81     * the kernel is more efficient than e2fsck in running the journal and
82     * processing orphaned inodes, and on at least one device with a
83     * performance issue in the emmc firmware, it can take e2fsck 2.5 minutes
84     * to do what the kernel does in about a second.
85     *
86     * After mounting and unmounting the filesystem, run e2fsck, and if an
87     * error is recorded in the filesystem superblock, e2fsck will do a full
88     * check.  Otherwise, it does nothing.  If the kernel cannot mount the
89     * filesytsem due to an error, e2fsck is still run to do a full check
90     * fix the filesystem.
91     */
92    ret = mount(c_source, c_target, "ext4", tmpmnt_flags, tmpmnt_opts);
93    if (!ret) {
94        int i;
95        for (i = 0; i < 5; i++) {
96            // Try to umount 5 times before continuing on.
97            // Should we try rebooting if all attempts fail?
98            int result = umount(c_target);
99            if (result == 0) {
100                break;
101            }
102            ALOGW("%s(): umount(%s)=%d: %s\n", __func__, c_target, result, strerror(errno));
103            sleep(1);
104        }
105    }
106
107    /*
108     * Some system images do not have e2fsck for licensing reasons
109     * (e.g. recent SDK system images). Detect these and skip the check.
110     */
111    if (access(kFsckPath, X_OK)) {
112        ALOGD("Not running %s on %s (executable not in system image)\n",
113                kFsckPath, c_source);
114    } else {
115        ALOGD("Running %s on %s\n", kFsckPath, c_source);
116
117        std::vector<std::string> cmd;
118        cmd.push_back(kFsckPath);
119        cmd.push_back("-y");
120        cmd.push_back(c_source);
121
122        // ext4 devices are currently always trusted
123        return ForkExecvp(cmd, sFsckContext);
124    }
125
126    return 0;
127}
128
129status_t Mount(const std::string& source, const std::string& target, bool ro,
130        bool remount, bool executable) {
131    int rc;
132    unsigned long flags;
133
134    const char* c_source = source.c_str();
135    const char* c_target = target.c_str();
136
137    flags = MS_NOATIME | MS_NODEV | MS_NOSUID | MS_DIRSYNC;
138
139    flags |= (executable ? 0 : MS_NOEXEC);
140    flags |= (ro ? MS_RDONLY : 0);
141    flags |= (remount ? MS_REMOUNT : 0);
142
143    rc = mount(c_source, c_target, "ext4", flags, NULL);
144
145    if (rc && errno == EROFS) {
146        SLOGE("%s appears to be a read only filesystem - retrying mount RO", c_source);
147        flags |= MS_RDONLY;
148        rc = mount(c_source, c_target, "ext4", flags, NULL);
149    }
150
151    return rc;
152}
153
154status_t Resize(const std::string& source, unsigned int numSectors) {
155    std::vector<std::string> cmd;
156    cmd.push_back(kResizefsPath);
157    cmd.push_back("-f");
158    cmd.push_back(source);
159    cmd.push_back(StringPrintf("%u", numSectors));
160
161    return ForkExecvp(cmd);
162}
163
164status_t Format(const std::string& source, unsigned int numSectors,
165        const std::string& target) {
166    std::vector<std::string> cmd;
167    cmd.push_back(kMkfsPath);
168    cmd.push_back("-J");
169
170    cmd.push_back("-a");
171    cmd.push_back(target);
172
173    if (numSectors) {
174        cmd.push_back("-l");
175        cmd.push_back(StringPrintf("%u", numSectors * 512));
176    }
177
178    // Always generate a real UUID
179    cmd.push_back("-u");
180    cmd.push_back(source);
181
182    return ForkExecvp(cmd);
183}
184
185}  // namespace ext4
186}  // namespace vold
187}  // namespace android
188