Volume.cpp revision a4886f1f8ed72e24a302a91a0ab18bc54b6f585e 
1/*
2 * Copyright (C) 2008 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 <stdlib.h>
18#include <string.h>
19#include <dirent.h>
20#include <errno.h>
21#include <fcntl.h>
22
23#include <sys/types.h>
24#include <sys/stat.h>
25#include <sys/types.h>
26#include <sys/mman.h>
27#include <sys/mount.h>
28
29#include <linux/kdev_t.h>
30
31#include <cutils/properties.h>
32
33#include <diskconfig/diskconfig.h>
34
35#define LOG_TAG "Vold"
36
37#include <cutils/log.h>
38
39#include "Volume.h"
40#include "VolumeManager.h"
41#include "ResponseCode.h"
42#include "Fat.h"
43#include "Process.h"
44
45extern "C" void dos_partition_dec(void const *pp, struct dos_partition *d);
46extern "C" void dos_partition_enc(void *pp, struct dos_partition *d);
47
48
49/*
50 * Secure directory - stuff that only root can see
51 */
52const char *Volume::SECDIR            = "/mnt/secure";
53
54/*
55 * Secure staging directory - where media is mounted for preparation
56 */
57const char *Volume::SEC_STGDIR        = "/mnt/secure/staging";
58
59/*
60 * Path to the directory on the media which contains publicly accessable
61 * asec imagefiles. This path will be obscured before the mount is
62 * exposed to non priviledged users.
63 */
64const char *Volume::SEC_STG_SECIMGDIR = "/mnt/secure/staging/.android_secure";
65
66/*
67 * Path to where *only* root can access asec imagefiles
68 */
69const char *Volume::SEC_ASECDIR       = "/mnt/secure/asec";
70
71/*
72 * Path to where secure containers are mounted
73 */
74const char *Volume::ASECDIR           = "/mnt/asec";
75
76/*
77 * Path to where OBBs are mounted
78 */
79const char *Volume::LOOPDIR           = "/mnt/obb";
80
81static const char *stateToStr(int state) {
82    if (state == Volume::State_Init)
83        return "Initializing";
84    else if (state == Volume::State_NoMedia)
85        return "No-Media";
86    else if (state == Volume::State_Idle)
87        return "Idle-Unmounted";
88    else if (state == Volume::State_Pending)
89        return "Pending";
90    else if (state == Volume::State_Mounted)
91        return "Mounted";
92    else if (state == Volume::State_Unmounting)
93        return "Unmounting";
94    else if (state == Volume::State_Checking)
95        return "Checking";
96    else if (state == Volume::State_Formatting)
97        return "Formatting";
98    else if (state == Volume::State_Shared)
99        return "Shared-Unmounted";
100    else if (state == Volume::State_SharedMnt)
101        return "Shared-Mounted";
102    else
103        return "Unknown-Error";
104}
105
106Volume::Volume(VolumeManager *vm, const char *label, const char *mount_point) {
107    mVm = vm;
108    mDebug = false;
109    mLabel = strdup(label);
110    mMountpoint = strdup(mount_point);
111    mState = Volume::State_Init;
112    mCurrentlyMountedKdev = -1;
113    mPartIdx = -1;
114}
115
116Volume::~Volume() {
117    free(mLabel);
118    free(mMountpoint);
119}
120
121void Volume::protectFromAutorunStupidity() {
122    char filename[255];
123
124    snprintf(filename, sizeof(filename), "%s/autorun.inf", SEC_STGDIR);
125    if (!access(filename, F_OK)) {
126        SLOGW("Volume contains an autorun.inf! - removing");
127        /*
128         * Ensure the filename is all lower-case so
129         * the process killer can find the inode.
130         * Probably being paranoid here but meh.
131         */
132        rename(filename, filename);
133        Process::killProcessesWithOpenFiles(filename, 2);
134        if (unlink(filename)) {
135            SLOGE("Failed to remove %s (%s)", filename, strerror(errno));
136        }
137    }
138}
139
140void Volume::setDebug(bool enable) {
141    mDebug = enable;
142}
143
144dev_t Volume::getDiskDevice() {
145    return MKDEV(0, 0);
146};
147
148dev_t Volume::getShareDevice() {
149    return getDiskDevice();
150}
151
152void Volume::handleVolumeShared() {
153}
154
155void Volume::handleVolumeUnshared() {
156}
157
158int Volume::handleBlockEvent(NetlinkEvent *evt) {
159    errno = ENOSYS;
160    return -1;
161}
162
163void Volume::setState(int state) {
164    char msg[255];
165    int oldState = mState;
166
167    if (oldState == state) {
168        SLOGW("Duplicate state (%d)\n", state);
169        return;
170    }
171
172    mState = state;
173
174    SLOGD("Volume %s state changing %d (%s) -> %d (%s)", mLabel,
175         oldState, stateToStr(oldState), mState, stateToStr(mState));
176    snprintf(msg, sizeof(msg),
177             "Volume %s %s state changed from %d (%s) to %d (%s)", getLabel(),
178             getMountpoint(), oldState, stateToStr(oldState), mState,
179             stateToStr(mState));
180
181    mVm->getBroadcaster()->sendBroadcast(ResponseCode::VolumeStateChange,
182                                         msg, false);
183}
184
185int Volume::createDeviceNode(const char *path, int major, int minor) {
186    mode_t mode = 0660 | S_IFBLK;
187    dev_t dev = (major << 8) | minor;
188    if (mknod(path, mode, dev) < 0) {
189        if (errno != EEXIST) {
190            return -1;
191        }
192    }
193    return 0;
194}
195
196int Volume::formatVol() {
197
198    if (getState() == Volume::State_NoMedia) {
199        errno = ENODEV;
200        return -1;
201    } else if (getState() != Volume::State_Idle) {
202        errno = EBUSY;
203        return -1;
204    }
205
206    if (isMountpointMounted(getMountpoint())) {
207        SLOGW("Volume is idle but appears to be mounted - fixing");
208        setState(Volume::State_Mounted);
209        // mCurrentlyMountedKdev = XXX
210        errno = EBUSY;
211        return -1;
212    }
213
214    bool formatEntireDevice = (mPartIdx == -1);
215    char devicePath[255];
216    dev_t diskNode = getDiskDevice();
217    dev_t partNode = MKDEV(MAJOR(diskNode), (formatEntireDevice ? 1 : mPartIdx));
218
219    setState(Volume::State_Formatting);
220
221    // Only initialize the MBR if we are formatting the entire device
222    if (formatEntireDevice) {
223        sprintf(devicePath, "/dev/block/vold/%d:%d",
224                MAJOR(diskNode), MINOR(diskNode));
225
226        if (initializeMbr(devicePath)) {
227            SLOGE("Failed to initialize MBR (%s)", strerror(errno));
228            goto err;
229        }
230    }
231
232    sprintf(devicePath, "/dev/block/vold/%d:%d",
233            MAJOR(partNode), MINOR(partNode));
234
235    if (mDebug) {
236        SLOGI("Formatting volume %s (%s)", getLabel(), devicePath);
237    }
238
239    if (Fat::format(devicePath, 0)) {
240        SLOGE("Failed to format (%s)", strerror(errno));
241        goto err;
242    }
243
244    setState(Volume::State_Idle);
245    return 0;
246err:
247    return -1;
248}
249
250bool Volume::isMountpointMounted(const char *path) {
251    char device[256];
252    char mount_path[256];
253    char rest[256];
254    FILE *fp;
255    char line[1024];
256
257    if (!(fp = fopen("/proc/mounts", "r"))) {
258        SLOGE("Error opening /proc/mounts (%s)", strerror(errno));
259        return false;
260    }
261
262    while(fgets(line, sizeof(line), fp)) {
263        line[strlen(line)-1] = '\0';
264        sscanf(line, "%255s %255s %255s\n", device, mount_path, rest);
265        if (!strcmp(mount_path, path)) {
266            fclose(fp);
267            return true;
268        }
269
270    }
271
272    fclose(fp);
273    return false;
274}
275
276int Volume::mountVol() {
277    dev_t deviceNodes[4];
278    int n, i, rc = 0;
279    char errmsg[255];
280
281    if (getState() == Volume::State_NoMedia) {
282        snprintf(errmsg, sizeof(errmsg),
283                 "Volume %s %s mount failed - no media",
284                 getLabel(), getMountpoint());
285        mVm->getBroadcaster()->sendBroadcast(
286                                         ResponseCode::VolumeMountFailedNoMedia,
287                                         errmsg, false);
288        errno = ENODEV;
289        return -1;
290    } else if (getState() != Volume::State_Idle) {
291        errno = EBUSY;
292        return -1;
293    }
294
295    if (isMountpointMounted(getMountpoint())) {
296        SLOGW("Volume is idle but appears to be mounted - fixing");
297        setState(Volume::State_Mounted);
298        // mCurrentlyMountedKdev = XXX
299        return 0;
300    }
301
302    n = getDeviceNodes((dev_t *) &deviceNodes, 4);
303    if (!n) {
304        SLOGE("Failed to get device nodes (%s)\n", strerror(errno));
305        return -1;
306    }
307
308    for (i = 0; i < n; i++) {
309        char devicePath[255];
310
311        sprintf(devicePath, "/dev/block/vold/%d:%d", MAJOR(deviceNodes[i]),
312                MINOR(deviceNodes[i]));
313
314        SLOGI("%s being considered for volume %s\n", devicePath, getLabel());
315
316        errno = 0;
317        setState(Volume::State_Checking);
318
319        if (Fat::check(devicePath)) {
320            if (errno == ENODATA) {
321                SLOGW("%s does not contain a FAT filesystem\n", devicePath);
322                continue;
323            }
324            errno = EIO;
325            /* Badness - abort the mount */
326            SLOGE("%s failed FS checks (%s)", devicePath, strerror(errno));
327            setState(Volume::State_Idle);
328            return -1;
329        }
330
331        /*
332         * Mount the device on our internal staging mountpoint so we can
333         * muck with it before exposing it to non priviledged users.
334         */
335        errno = 0;
336        if (Fat::doMount(devicePath, "/mnt/secure/staging", false, false, false,
337                1000, 1015, 0702, true)) {
338            SLOGE("%s failed to mount via VFAT (%s)\n", devicePath, strerror(errno));
339            continue;
340        }
341
342        SLOGI("Device %s, target %s mounted @ /mnt/secure/staging", devicePath, getMountpoint());
343
344        protectFromAutorunStupidity();
345
346        if (createBindMounts()) {
347            SLOGE("Failed to create bindmounts (%s)", strerror(errno));
348            umount("/mnt/secure/staging");
349            setState(Volume::State_Idle);
350            return -1;
351        }
352
353        /*
354         * Now that the bindmount trickery is done, atomically move the
355         * whole subtree to expose it to non priviledged users.
356         */
357        if (doMoveMount("/mnt/secure/staging", getMountpoint(), false)) {
358            SLOGE("Failed to move mount (%s)", strerror(errno));
359            umount("/mnt/secure/staging");
360            setState(Volume::State_Idle);
361            return -1;
362        }
363        setState(Volume::State_Mounted);
364        mCurrentlyMountedKdev = deviceNodes[i];
365        return 0;
366    }
367
368    SLOGE("Volume %s found no suitable devices for mounting :(\n", getLabel());
369    setState(Volume::State_Idle);
370
371    return -1;
372}
373
374int Volume::createBindMounts() {
375    unsigned long flags;
376
377    /*
378     * Rename old /android_secure -> /.android_secure
379     */
380    if (!access("/mnt/secure/staging/android_secure", R_OK | X_OK) &&
381         access(SEC_STG_SECIMGDIR, R_OK | X_OK)) {
382        if (rename("/mnt/secure/staging/android_secure", SEC_STG_SECIMGDIR)) {
383            SLOGE("Failed to rename legacy asec dir (%s)", strerror(errno));
384        }
385    }
386
387    /*
388     * Ensure that /android_secure exists and is a directory
389     */
390    if (access(SEC_STG_SECIMGDIR, R_OK | X_OK)) {
391        if (errno == ENOENT) {
392            if (mkdir(SEC_STG_SECIMGDIR, 0777)) {
393                SLOGE("Failed to create %s (%s)", SEC_STG_SECIMGDIR, strerror(errno));
394                return -1;
395            }
396        } else {
397            SLOGE("Failed to access %s (%s)", SEC_STG_SECIMGDIR, strerror(errno));
398            return -1;
399        }
400    } else {
401        struct stat sbuf;
402
403        if (stat(SEC_STG_SECIMGDIR, &sbuf)) {
404            SLOGE("Failed to stat %s (%s)", SEC_STG_SECIMGDIR, strerror(errno));
405            return -1;
406        }
407        if (!S_ISDIR(sbuf.st_mode)) {
408            SLOGE("%s is not a directory", SEC_STG_SECIMGDIR);
409            errno = ENOTDIR;
410            return -1;
411        }
412    }
413
414    /*
415     * Bind mount /mnt/secure/staging/android_secure -> /mnt/secure/asec so we'll
416     * have a root only accessable mountpoint for it.
417     */
418    if (mount(SEC_STG_SECIMGDIR, SEC_ASECDIR, "", MS_BIND, NULL)) {
419        SLOGE("Failed to bind mount points %s -> %s (%s)",
420                SEC_STG_SECIMGDIR, SEC_ASECDIR, strerror(errno));
421        return -1;
422    }
423
424    /*
425     * Mount a read-only, zero-sized tmpfs  on <mountpoint>/android_secure to
426     * obscure the underlying directory from everybody - sneaky eh? ;)
427     */
428    if (mount("tmpfs", SEC_STG_SECIMGDIR, "tmpfs", MS_RDONLY, "size=0,mode=000,uid=0,gid=0")) {
429        SLOGE("Failed to obscure %s (%s)", SEC_STG_SECIMGDIR, strerror(errno));
430        umount("/mnt/asec_secure");
431        return -1;
432    }
433
434    return 0;
435}
436
437int Volume::doMoveMount(const char *src, const char *dst, bool force) {
438    unsigned int flags = MS_MOVE;
439    int retries = 5;
440
441    while(retries--) {
442        if (!mount(src, dst, "", flags, NULL)) {
443            if (mDebug) {
444                SLOGD("Moved mount %s -> %s sucessfully", src, dst);
445            }
446            return 0;
447        } else if (errno != EBUSY) {
448            SLOGE("Failed to move mount %s -> %s (%s)", src, dst, strerror(errno));
449            return -1;
450        }
451        int action = 0;
452
453        if (force) {
454            if (retries == 1) {
455                action = 2; // SIGKILL
456            } else if (retries == 2) {
457                action = 1; // SIGHUP
458            }
459        }
460        SLOGW("Failed to move %s -> %s (%s, retries %d, action %d)",
461                src, dst, strerror(errno), retries, action);
462        Process::killProcessesWithOpenFiles(src, action);
463        usleep(1000*250);
464    }
465
466    errno = EBUSY;
467    SLOGE("Giving up on move %s -> %s (%s)", src, dst, strerror(errno));
468    return -1;
469}
470
471int Volume::doUnmount(const char *path, bool force) {
472    int retries = 10;
473
474    if (mDebug) {
475        SLOGD("Unmounting {%s}, force = %d", path, force);
476    }
477
478    while (retries--) {
479        if (!umount(path) || errno == EINVAL || errno == ENOENT) {
480            SLOGI("%s sucessfully unmounted", path);
481            return 0;
482        }
483
484        int action = 0;
485
486        if (force) {
487            if (retries == 1) {
488                action = 2; // SIGKILL
489            } else if (retries == 2) {
490                action = 1; // SIGHUP
491            }
492        }
493
494        SLOGW("Failed to unmount %s (%s, retries %d, action %d)",
495                path, strerror(errno), retries, action);
496
497        Process::killProcessesWithOpenFiles(path, action);
498        usleep(1000*1000);
499    }
500    errno = EBUSY;
501    SLOGE("Giving up on unmount %s (%s)", path, strerror(errno));
502    return -1;
503}
504
505int Volume::unmountVol(bool force) {
506    int i, rc;
507
508    if (getState() != Volume::State_Mounted) {
509        SLOGE("Volume %s unmount request when not mounted", getLabel());
510        errno = EINVAL;
511        return -1;
512    }
513
514    setState(Volume::State_Unmounting);
515    usleep(1000 * 1000); // Give the framework some time to react
516
517    /*
518     * First move the mountpoint back to our internal staging point
519     * so nobody else can muck with it while we work.
520     */
521    if (doMoveMount(getMountpoint(), SEC_STGDIR, force)) {
522        SLOGE("Failed to move mount %s => %s (%s)", getMountpoint(), SEC_STGDIR, strerror(errno));
523        setState(Volume::State_Mounted);
524        return -1;
525    }
526
527    protectFromAutorunStupidity();
528
529    /*
530     * Unmount the tmpfs which was obscuring the asec image directory
531     * from non root users
532     */
533
534    if (doUnmount(Volume::SEC_STG_SECIMGDIR, force)) {
535        SLOGE("Failed to unmount tmpfs on %s (%s)", SEC_STG_SECIMGDIR, strerror(errno));
536        goto fail_republish;
537    }
538
539    /*
540     * Remove the bindmount we were using to keep a reference to
541     * the previously obscured directory.
542     */
543
544    if (doUnmount(Volume::SEC_ASECDIR, force)) {
545        SLOGE("Failed to remove bindmount on %s (%s)", SEC_ASECDIR, strerror(errno));
546        goto fail_remount_tmpfs;
547    }
548
549    /*
550     * Finally, unmount the actual block device from the staging dir
551     */
552    if (doUnmount(Volume::SEC_STGDIR, force)) {
553        SLOGE("Failed to unmount %s (%s)", SEC_STGDIR, strerror(errno));
554        goto fail_recreate_bindmount;
555    }
556
557    SLOGI("%s unmounted sucessfully", getMountpoint());
558
559    setState(Volume::State_Idle);
560    mCurrentlyMountedKdev = -1;
561    return 0;
562
563    /*
564     * Failure handling - try to restore everything back the way it was
565     */
566fail_recreate_bindmount:
567    if (mount(SEC_STG_SECIMGDIR, SEC_ASECDIR, "", MS_BIND, NULL)) {
568        SLOGE("Failed to restore bindmount after failure! - Storage will appear offline!");
569        goto out_nomedia;
570    }
571fail_remount_tmpfs:
572    if (mount("tmpfs", SEC_STG_SECIMGDIR, "tmpfs", MS_RDONLY, "size=0,mode=0,uid=0,gid=0")) {
573        SLOGE("Failed to restore tmpfs after failure! - Storage will appear offline!");
574        goto out_nomedia;
575    }
576fail_republish:
577    if (doMoveMount(SEC_STGDIR, getMountpoint(), force)) {
578        SLOGE("Failed to republish mount after failure! - Storage will appear offline!");
579        goto out_nomedia;
580    }
581
582    setState(Volume::State_Mounted);
583    return -1;
584
585out_nomedia:
586    setState(Volume::State_NoMedia);
587    return -1;
588}
589int Volume::initializeMbr(const char *deviceNode) {
590    struct disk_info dinfo;
591
592    memset(&dinfo, 0, sizeof(dinfo));
593
594    if (!(dinfo.part_lst = (struct part_info *) malloc(MAX_NUM_PARTS * sizeof(struct part_info)))) {
595        SLOGE("Failed to malloc prt_lst");
596        return -1;
597    }
598
599    memset(dinfo.part_lst, 0, MAX_NUM_PARTS * sizeof(struct part_info));
600    dinfo.device = strdup(deviceNode);
601    dinfo.scheme = PART_SCHEME_MBR;
602    dinfo.sect_size = 512;
603    dinfo.skip_lba = 2048;
604    dinfo.num_lba = 0;
605    dinfo.num_parts = 1;
606
607    struct part_info *pinfo = &dinfo.part_lst[0];
608
609    pinfo->name = strdup("android_sdcard");
610    pinfo->flags |= PART_ACTIVE_FLAG;
611    pinfo->type = PC_PART_TYPE_FAT32;
612    pinfo->len_kb = -1;
613
614    int rc = apply_disk_config(&dinfo, 0);
615
616    if (rc) {
617        SLOGE("Failed to apply disk configuration (%d)", rc);
618        goto out;
619    }
620
621 out:
622    free(pinfo->name);
623    free(dinfo.device);
624    free(dinfo.part_lst);
625
626    return rc;
627}
628