Volume.cpp revision fcf24fe62f98c5d44431aa575555569c2c7a29b0
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 "diskmbr.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 76static const char *stateToStr(int state) { 77 if (state == Volume::State_Init) 78 return "Initializing"; 79 else if (state == Volume::State_NoMedia) 80 return "No-Media"; 81 else if (state == Volume::State_Idle) 82 return "Idle-Unmounted"; 83 else if (state == Volume::State_Pending) 84 return "Pending"; 85 else if (state == Volume::State_Mounted) 86 return "Mounted"; 87 else if (state == Volume::State_Unmounting) 88 return "Unmounting"; 89 else if (state == Volume::State_Checking) 90 return "Checking"; 91 else if (state == Volume::State_Formatting) 92 return "Formatting"; 93 else if (state == Volume::State_Shared) 94 return "Shared-Unmounted"; 95 else if (state == Volume::State_SharedMnt) 96 return "Shared-Mounted"; 97 else 98 return "Unknown-Error"; 99} 100 101Volume::Volume(VolumeManager *vm, const char *label, const char *mount_point) { 102 mVm = vm; 103 mLabel = strdup(label); 104 mMountpoint = strdup(mount_point); 105 mState = Volume::State_Init; 106 mCurrentlyMountedKdev = -1; 107} 108 109Volume::~Volume() { 110 free(mLabel); 111 free(mMountpoint); 112} 113 114dev_t Volume::getDiskDevice() { 115 return MKDEV(0, 0); 116}; 117 118void Volume::handleVolumeShared() { 119} 120 121void Volume::handleVolumeUnshared() { 122} 123 124int Volume::handleBlockEvent(NetlinkEvent *evt) { 125 errno = ENOSYS; 126 return -1; 127} 128 129void Volume::setState(int state) { 130 char msg[255]; 131 int oldState = mState; 132 133 if (oldState == state) { 134 LOGW("Duplicate state (%d)\n", state); 135 return; 136 } 137 138 mState = state; 139 140 LOGD("Volume %s state changing %d (%s) -> %d (%s)", mLabel, 141 oldState, stateToStr(oldState), mState, stateToStr(mState)); 142 snprintf(msg, sizeof(msg), 143 "Volume %s %s state changed from %d (%s) to %d (%s)", getLabel(), 144 getMountpoint(), oldState, stateToStr(oldState), mState, 145 stateToStr(mState)); 146 147 mVm->getBroadcaster()->sendBroadcast(ResponseCode::VolumeStateChange, 148 msg, false); 149} 150 151int Volume::createDeviceNode(const char *path, int major, int minor) { 152 mode_t mode = 0660 | S_IFBLK; 153 dev_t dev = (major << 8) | minor; 154 if (mknod(path, mode, dev) < 0) { 155 if (errno != EEXIST) { 156 return -1; 157 } 158 } 159 return 0; 160} 161 162int Volume::formatVol() { 163 164 if (getState() == Volume::State_NoMedia) { 165 errno = ENODEV; 166 return -1; 167 } else if (getState() != Volume::State_Idle) { 168 errno = EBUSY; 169 return -1; 170 } 171 172 if (isMountpointMounted(getMountpoint())) { 173 LOGW("Volume is idle but appears to be mounted - fixing"); 174 setState(Volume::State_Mounted); 175 // mCurrentlyMountedKdev = XXX 176 errno = EBUSY; 177 return -1; 178 } 179 180 char devicePath[255]; 181 dev_t diskNode = getDiskDevice(); 182 dev_t partNode = MKDEV(MAJOR(diskNode), 1); // XXX: Hmmm 183 184 sprintf(devicePath, "/dev/block/vold/%d:%d", 185 MAJOR(diskNode), MINOR(diskNode)); 186 187 LOGI("Formatting volume %s (%s)", getLabel(), devicePath); 188 189 if (initializeMbr(devicePath)) { 190 LOGE("Failed to initialize MBR (%s)", strerror(errno)); 191 goto err; 192 } 193 194 sprintf(devicePath, "/dev/block/vold/%d:%d", 195 MAJOR(partNode), MINOR(partNode)); 196 197 if (Fat::format(devicePath, 0)) { 198 LOGE("Failed to format (%s)", strerror(errno)); 199 goto err; 200 } 201 202 return 0; 203err: 204 return -1; 205} 206 207bool Volume::isMountpointMounted(const char *path) { 208 char device[256]; 209 char mount_path[256]; 210 char rest[256]; 211 FILE *fp; 212 char line[1024]; 213 214 if (!(fp = fopen("/proc/mounts", "r"))) { 215 LOGE("Error opening /proc/mounts (%s)", strerror(errno)); 216 return false; 217 } 218 219 while(fgets(line, sizeof(line), fp)) { 220 line[strlen(line)-1] = '\0'; 221 sscanf(line, "%255s %255s %255s\n", device, mount_path, rest); 222 if (!strcmp(mount_path, path)) { 223 fclose(fp); 224 return true; 225 } 226 227 } 228 229 fclose(fp); 230 return false; 231} 232 233int Volume::mountVol() { 234 dev_t deviceNodes[4]; 235 int n, i, rc = 0; 236 char errmsg[255]; 237 238 if (getState() == Volume::State_NoMedia) { 239 snprintf(errmsg, sizeof(errmsg), 240 "Volume %s %s mount failed - no media", 241 getLabel(), getMountpoint()); 242 mVm->getBroadcaster()->sendBroadcast( 243 ResponseCode::VolumeMountFailedNoMedia, 244 errmsg, false); 245 errno = ENODEV; 246 return -1; 247 } else if (getState() != Volume::State_Idle) { 248 errno = EBUSY; 249 return -1; 250 } 251 252 if (isMountpointMounted(getMountpoint())) { 253 LOGW("Volume is idle but appears to be mounted - fixing"); 254 setState(Volume::State_Mounted); 255 // mCurrentlyMountedKdev = XXX 256 return 0; 257 } 258 259 n = getDeviceNodes((dev_t *) &deviceNodes, 4); 260 if (!n) { 261 LOGE("Failed to get device nodes (%s)\n", strerror(errno)); 262 return -1; 263 } 264 265 for (i = 0; i < n; i++) { 266 char devicePath[255]; 267 268 sprintf(devicePath, "/dev/block/vold/%d:%d", MAJOR(deviceNodes[i]), 269 MINOR(deviceNodes[i])); 270 271 LOGI("%s being considered for volume %s\n", devicePath, getLabel()); 272 273 errno = 0; 274 setState(Volume::State_Checking); 275 276 if (Fat::check(devicePath)) { 277 if (errno == ENODATA) { 278 LOGW("%s does not contain a FAT filesystem\n", devicePath); 279 continue; 280 } 281 errno = EIO; 282 /* Badness - abort the mount */ 283 LOGE("%s failed FS checks (%s)", devicePath, strerror(errno)); 284 setState(Volume::State_Idle); 285 return -1; 286 } 287 288 /* 289 * Mount the device on our internal staging mountpoint so we can 290 * muck with it before exposing it to non priviledged users. 291 */ 292 errno = 0; 293 if (Fat::doMount(devicePath, "/mnt/secure/staging", false, false, 1000, 1015, 0702, true)) { 294 LOGE("%s failed to mount via VFAT (%s)\n", devicePath, strerror(errno)); 295 continue; 296 } 297 298 LOGI("Device %s, target %s mounted @ /mnt/secure/staging", devicePath, getMountpoint()); 299 300 if (createBindMounts()) { 301 LOGE("Failed to create bindmounts (%s)", strerror(errno)); 302 umount("/mnt/secure/staging"); 303 setState(Volume::State_Idle); 304 return -1; 305 } 306 307 /* 308 * Now that the bindmount trickery is done, atomically move the 309 * whole subtree to expose it to non priviledged users. 310 */ 311 if (doMoveMount("/mnt/secure/staging", getMountpoint(), false)) { 312 LOGE("Failed to move mount (%s)", strerror(errno)); 313 umount("/mnt/secure/staging"); 314 setState(Volume::State_Idle); 315 return -1; 316 } 317 setState(Volume::State_Mounted); 318 mCurrentlyMountedKdev = deviceNodes[i]; 319 return 0; 320 } 321 322 LOGE("Volume %s found no suitable devices for mounting :(\n", getLabel()); 323 setState(Volume::State_Idle); 324 325 return -1; 326} 327 328int Volume::createBindMounts() { 329 unsigned long flags; 330 331 /* 332 * Rename old /android_secure -> /.android_secure 333 */ 334 if (!access("/mnt/secure/staging/android_secure", R_OK | X_OK) && 335 access(SEC_STG_SECIMGDIR, R_OK | X_OK)) { 336 if (rename("/mnt/secure/staging/android_secure", SEC_STG_SECIMGDIR)) { 337 LOGE("Failed to rename legacy asec dir (%s)", strerror(errno)); 338 } 339 } 340 341 /* 342 * Ensure that /android_secure exists and is a directory 343 */ 344 if (access(SEC_STG_SECIMGDIR, R_OK | X_OK)) { 345 if (errno == ENOENT) { 346 if (mkdir(SEC_STG_SECIMGDIR, 0777)) { 347 LOGE("Failed to create %s (%s)", SEC_STG_SECIMGDIR, strerror(errno)); 348 return -1; 349 } 350 } else { 351 LOGE("Failed to access %s (%s)", SEC_STG_SECIMGDIR, strerror(errno)); 352 return -1; 353 } 354 } else { 355 struct stat sbuf; 356 357 if (stat(SEC_STG_SECIMGDIR, &sbuf)) { 358 LOGE("Failed to stat %s (%s)", SEC_STG_SECIMGDIR, strerror(errno)); 359 return -1; 360 } 361 if (!S_ISDIR(sbuf.st_mode)) { 362 LOGE("%s is not a directory", SEC_STG_SECIMGDIR); 363 errno = ENOTDIR; 364 return -1; 365 } 366 } 367 368 /* 369 * Bind mount /mnt/secure/staging/android_secure -> /mnt/secure/asec so we'll 370 * have a root only accessable mountpoint for it. 371 */ 372 if (mount(SEC_STG_SECIMGDIR, SEC_ASECDIR, "", MS_BIND, NULL)) { 373 LOGE("Failed to bind mount points %s -> %s (%s)", 374 SEC_STG_SECIMGDIR, SEC_ASECDIR, strerror(errno)); 375 return -1; 376 } 377 378 /* 379 * Mount a read-only, zero-sized tmpfs on <mountpoint>/android_secure to 380 * obscure the underlying directory from everybody - sneaky eh? ;) 381 */ 382 if (mount("tmpfs", SEC_STG_SECIMGDIR, "tmpfs", MS_RDONLY, "size=0,mode=000,uid=0,gid=0")) { 383 LOGE("Failed to obscure %s (%s)", SEC_STG_SECIMGDIR, strerror(errno)); 384 umount("/mnt/asec_secure"); 385 return -1; 386 } 387 388 return 0; 389} 390 391int Volume::doMoveMount(const char *src, const char *dst, bool force) { 392 unsigned int flags = MS_MOVE; 393 int retries = 5; 394 395 while(retries--) { 396 if (!mount(src, dst, "", flags, NULL)) { 397 LOGD("Moved mount %s -> %s sucessfully", src, dst); 398 return 0; 399 } else if (errno != EBUSY) { 400 LOGE("Failed to move mount %s -> %s (%s)", src, dst, strerror(errno)); 401 return -1; 402 } 403 int action = 0; 404 405 if (force) { 406 if (retries == 1) { 407 action = 2; // SIGKILL 408 } else if (retries == 2) { 409 action = 1; // SIGHUP 410 } 411 } 412 LOGW("Failed to move %s -> %s (%s, retries %d, action %d)", 413 src, dst, strerror(errno), retries, action); 414 Process::killProcessesWithOpenFiles(src, action); 415 usleep(1000*250); 416 } 417 418 errno = EBUSY; 419 LOGE("Giving up on move %s -> %s (%s)", src, dst, strerror(errno)); 420 return -1; 421} 422 423int Volume::doUnmount(const char *path, bool force) { 424 int retries = 10; 425 426 while (retries--) { 427 if (!umount(path) || errno == EINVAL || errno == ENOENT) { 428 LOGI("%s sucessfully unmounted", path); 429 return 0; 430 } 431 432 int action = 0; 433 434 if (force) { 435 if (retries == 1) { 436 action = 2; // SIGKILL 437 } else if (retries == 2) { 438 action = 1; // SIGHUP 439 } 440 } 441 442 LOGW("Failed to unmount %s (%s, retries %d, action %d)", 443 path, strerror(errno), retries, action); 444 445 Process::killProcessesWithOpenFiles(path, action); 446 usleep(1000*1000); 447 } 448 errno = EBUSY; 449 LOGE("Giving up on unmount %s (%s)", path, strerror(errno)); 450 return -1; 451} 452 453int Volume::unmountVol(bool force) { 454 int i, rc; 455 456 if (getState() != Volume::State_Mounted) { 457 LOGE("Volume %s unmount request when not mounted", getLabel()); 458 errno = EINVAL; 459 return -1; 460 } 461 462 setState(Volume::State_Unmounting); 463 usleep(1000 * 1000); // Give the framework some time to react 464 465 /* 466 * First move the mountpoint back to our internal staging point 467 * so nobody else can muck with it while we work. 468 */ 469 if (doMoveMount(getMountpoint(), SEC_STGDIR, force)) { 470 LOGE("Failed to move mount %s => %s (%s)", getMountpoint(), SEC_STGDIR, strerror(errno)); 471 setState(Volume::State_Mounted); 472 return -1; 473 } 474 475 /* 476 * Unmount the tmpfs which was obscuring the asec image directory 477 * from non root users 478 */ 479 480 if (doUnmount(Volume::SEC_STG_SECIMGDIR, force)) { 481 LOGE("Failed to unmount tmpfs on %s (%s)", SEC_STG_SECIMGDIR, strerror(errno)); 482 goto fail_republish; 483 } 484 485 /* 486 * Remove the bindmount we were using to keep a reference to 487 * the previously obscured directory. 488 */ 489 490 if (doUnmount(Volume::SEC_ASECDIR, force)) { 491 LOGE("Failed to remove bindmount on %s (%s)", SEC_ASECDIR, strerror(errno)); 492 goto fail_remount_tmpfs; 493 } 494 495 /* 496 * Finally, unmount the actual block device from the staging dir 497 */ 498 if (doUnmount(Volume::SEC_STGDIR, force)) { 499 LOGE("Failed to unmount %s (%s)", SEC_STGDIR, strerror(errno)); 500 goto fail_recreate_bindmount; 501 } 502 503 LOGI("%s unmounted sucessfully", getMountpoint()); 504 505 setState(Volume::State_Idle); 506 mCurrentlyMountedKdev = -1; 507 return 0; 508 509 /* 510 * Failure handling - try to restore everything back the way it was 511 */ 512fail_recreate_bindmount: 513 if (mount(SEC_STG_SECIMGDIR, SEC_ASECDIR, "", MS_BIND, NULL)) { 514 LOGE("Failed to restore bindmount after failure! - Storage will appear offline!"); 515 goto out_nomedia; 516 } 517fail_remount_tmpfs: 518 if (mount("tmpfs", SEC_STG_SECIMGDIR, "tmpfs", MS_RDONLY, "size=0,mode=0,uid=0,gid=0")) { 519 LOGE("Failed to restore tmpfs after failure! - Storage will appear offline!"); 520 goto out_nomedia; 521 } 522fail_republish: 523 if (doMoveMount(SEC_STGDIR, getMountpoint(), force)) { 524 LOGE("Failed to republish mount after failure! - Storage will appear offline!"); 525 goto out_nomedia; 526 } 527 528 setState(Volume::State_Mounted); 529 return -1; 530 531out_nomedia: 532 setState(Volume::State_NoMedia); 533 return -1; 534} 535 536int Volume::initializeMbr(const char *deviceNode) { 537 int fd, rc; 538 unsigned char block[512]; 539 struct dos_partition part; 540 unsigned int nr_sec; 541 542 if ((fd = open(deviceNode, O_RDWR)) < 0) { 543 LOGE("Error opening disk file (%s)", strerror(errno)); 544 return -1; 545 } 546 547 if (ioctl(fd, BLKGETSIZE, &nr_sec)) { 548 LOGE("Unable to get device size (%s)", strerror(errno)); 549 close(fd); 550 return -1; 551 } 552 553 memset(&part, 0, sizeof(part)); 554 part.dp_flag = 0x80; 555 part.dp_typ = 0xc; 556 part.dp_start = ((1024 * 64) / 512) + 1; 557 part.dp_size = nr_sec - part.dp_start; 558 559 memset(block, 0, sizeof(block)); 560 block[0x1fe] = 0x55; 561 block[0x1ff] = 0xaa; 562 563 dos_partition_enc(block + DOSPARTOFF, &part); 564 565 if (write(fd, block, sizeof(block)) < 0) { 566 LOGE("Error writing MBR (%s)", strerror(errno)); 567 close(fd); 568 return -1; 569 } 570 571 if (ioctl(fd, BLKRRPART, NULL) < 0) { 572 LOGE("Error re-reading partition table (%s)", strerror(errno)); 573 close(fd); 574 return -1; 575 } 576 close(fd); 577 return 0; 578} 579