summaryrefslogtreecommitdiffstats
path: root/Fat.cpp
blob: 82a3f7ad98ab10bcf2ebbd214a8afcc718e80654 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
/*
 * Copyright (C) 2008 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <sys/mount.h>

#include <linux/kdev_t.h>
#include <linux/fs.h>

#define LOG_TAG "Vold"

#include <cutils/log.h>
#include <cutils/properties.h>

#include "Fat.h"

static char FSCK_MSDOS_PATH[] = "/system/bin/fsck_msdos";
static char MKDOSFS_PATH[] = "/system/bin/newfs_msdos";
extern "C" int logwrap(int argc, const char **argv, int background);
extern "C" int mount(const char *, const char *, const char *, unsigned long, const void *);

int Fat::check(const char *fsPath) {
    bool rw = true;
    if (access(FSCK_MSDOS_PATH, X_OK)) {
        SLOGW("Skipping fs checks\n");
        return 0;
    }

    int pass = 1;
    int rc = 0;
    do {
        const char *args[5];
        args[0] = FSCK_MSDOS_PATH;
        args[1] = "-p";
        args[2] = "-f";
        args[3] = fsPath;
        args[4] = NULL;

        rc = logwrap(4, args, 1);

        switch(rc) {
        case 0:
            SLOGI("Filesystem check completed OK");
            return 0;

        case 2:
            SLOGE("Filesystem check failed (not a FAT filesystem)");
            errno = ENODATA;
            return -1;

        case 4:
            if (pass++ <= 3) {
                SLOGW("Filesystem modified - rechecking (pass %d)",
                        pass);
                continue;
            }
            SLOGE("Failing check after too many rechecks");
            errno = EIO;
            return -1;

        default:
            SLOGE("Filesystem check failed (unknown exit code %d)", rc);
            errno = EIO;
            return -1;
        }
    } while (0);

    return 0;
}

int Fat::doMount(const char *fsPath, const char *mountPoint,
                 bool ro, bool remount, bool executable,
                 int ownerUid, int ownerGid, int permMask, bool createLost) {
    int rc;
    unsigned long flags;
    char mountData[255];

    flags = MS_NODEV | MS_NOSUID | MS_DIRSYNC;

    flags |= (executable ? 0 : MS_NOEXEC);
    flags |= (ro ? MS_RDONLY : 0);
    flags |= (remount ? MS_REMOUNT : 0);

    /*
     * Note: This is a temporary hack. If the sampling profiler is enabled,
     * we make the SD card world-writable so any process can write snapshots.
     *
     * TODO: Remove this code once we have a drop box in system_server.
     */
    char value[PROPERTY_VALUE_MAX];
    property_get("persist.sampling_profiler", value, "");
    if (value[0] == '1') {
        SLOGW("The SD card is world-writable because the"
            " 'persist.sampling_profiler' system property is set to '1'.");
        permMask = 0;
    }

    sprintf(mountData,
            "utf8,uid=%d,gid=%d,fmask=%o,dmask=%o,shortname=mixed",
            ownerUid, ownerGid, permMask, permMask);

    rc = mount(fsPath, mountPoint, "vfat", flags, mountData);

    if (rc && errno == EROFS) {
        SLOGE("%s appears to be a read only filesystem - retrying mount RO", fsPath);
        flags |= MS_RDONLY;
        rc = mount(fsPath, mountPoint, "vfat", flags, mountData);
    }

    if (rc == 0 && createLost) {
        char *lost_path;
        asprintf(&lost_path, "%s/LOST.DIR", mountPoint);
        if (access(lost_path, F_OK)) {
            /*
             * Create a LOST.DIR in the root so we have somewhere to put
             * lost cluster chains (fsck_msdos doesn't currently do this)
             */
            if (mkdir(lost_path, 0755)) {
                SLOGE("Unable to create LOST.DIR (%s)", strerror(errno));
            }
        }
        free(lost_path);
    }

    return rc;
}

int Fat::format(const char *fsPath, unsigned int numSectors) {
    int fd;
    const char *args[11];
    int rc;

    args[0] = MKDOSFS_PATH;
    args[1] = "-F";
    args[2] = "32";
    args[3] = "-O";
    args[4] = "android";
    args[5] = "-c";
    args[6] = "8";

    if (numSectors) {
        char tmp[32];
        snprintf(tmp, sizeof(tmp), "%u", numSectors);
        const char *size = tmp;
        args[7] = "-s";
        args[8] = size;
        args[9] = fsPath;
        args[10] = NULL;
        rc = logwrap(11, args, 1);
    } else {
        args[7] = fsPath;
        args[8] = NULL;
        rc = logwrap(9, args, 1);
    }

    if (rc == 0) {
        SLOGI("Filesystem formatted OK");
        return 0;
    } else {
        SLOGE("Format failed (unknown exit code %d)", rc);
        errno = EIO;
        return -1;
    }
    return 0;
}