Checkpoint of better dynamic device support.
This is the first in a series of changes that are designed to
introduce better support for dynamic block devices.
It starts by defining a new Volume object which represents a storage
endpoint that knows how to mount, unmount, and format itself. This
could be a filesystem directly on a partition, or it could be an
emulated FUSE filesystem, an ASEC, or an OBB.
These new volumes can be "stacked" so that unmounting a volume will
also unmount any volumes stacked above it. Volumes that provide
shared storage can also be asked to present themselves (through bind
mounts) into user-specific mount areas.
This change also adds a Disk class which is created based on block
kernel netlink events. Instead of waiting for partition events from
the kernel, it uses gptfdisk to read partition details and creates
the relevant Volume objects.
Change-Id: I0e8bc1f8f9dcb24405f5e795c0658998e22ae2f7
diff --git a/PublicVolume.cpp b/PublicVolume.cpp
new file mode 100644
index 0000000..78c8fa5
--- /dev/null
+++ b/PublicVolume.cpp
@@ -0,0 +1,251 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#define LOG_TAG "Vold"
+
+#include "Fat.h"
+#include "PublicVolume.h"
+#include "Utils.h"
+
+#include <cutils/fs.h>
+#include <cutils/log.h>
+#include <utils/file.h>
+#include <utils/stringprintf.h>
+#include <private/android_filesystem_config.h>
+
+#include <fcntl.h>
+#include <stdlib.h>
+#include <sys/mount.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+namespace android {
+namespace vold {
+
+static const char* kBlkidPath = "/system/bin/blkid";
+static const char* kFusePath = "/system/bin/sdcard";
+
+static const char* kUserMountPath = "/mnt/user";
+
+PublicVolume::PublicVolume(dev_t device) :
+ VolumeBase(VolumeType::kPublic), mDevice(device), mFusePid(0), mPrimary(false) {
+ mId = StringPrintf("public:%ud:%ud", major(device), minor(device));
+ mDevPath = StringPrintf("/dev/block/vold/%ud:%ud", major(device), minor(device));
+ mRawPath = StringPrintf("/mnt/media_rw/public_raw_%ud:%ud", major(device), minor(device));
+ mFusePath = StringPrintf("/mnt/media_rw/public_fuse_%ud:%ud", major(device), minor(device));
+
+ CreateDeviceNode(mDevPath, device);
+}
+
+PublicVolume::~PublicVolume() {
+ DestroyDeviceNode(mDevPath);
+}
+
+status_t PublicVolume::readMetadata() {
+ mFsUuid = "";
+ mFsLabel = "";
+
+ std::string path(StringPrintf("%s -c /dev/null %s", kBlkidPath, mDevPath.c_str()));
+ FILE* fp = popen(path.c_str(), "r");
+ if (!fp) {
+ ALOGE("Failed to run %s: %s", path.c_str(), strerror(errno));
+ return -errno;
+ }
+
+ char line[1024];
+ char value[128];
+ if (fgets(line, sizeof(line), fp) != nullptr) {
+ ALOGD("blkid identified as %s", line);
+
+ char* start = strstr(line, "UUID=");
+ if (start != nullptr && sscanf(start + 5, "\"%127[^\"]\"", value) == 1) {
+ mFsUuid = value;
+ }
+
+ start = strstr(line, "LABEL=");
+ if (start != nullptr && sscanf(start + 6, "\"%127[^\"]\"", value) == 1) {
+ mFsLabel = value;
+ }
+ } else {
+ ALOGW("blkid failed to identify %s", mDevPath.c_str());
+ return -ENODATA;
+ }
+
+ pclose(fp);
+
+ // TODO: broadcast ident to framework
+ return OK;
+}
+
+status_t PublicVolume::initAsecStage() {
+ std::string legacyPath(mRawPath + "/android_secure");
+ std::string securePath(mRawPath + "/.android_secure");
+
+ // Recover legacy secure path
+ if (!access(legacyPath.c_str(), R_OK | X_OK)
+ && access(securePath.c_str(), R_OK | X_OK)) {
+ if (rename(legacyPath.c_str(), securePath.c_str())) {
+ SLOGE("Failed to rename legacy ASEC dir: %s", strerror(errno));
+ }
+ }
+
+ if (fs_prepare_dir(securePath.c_str(), 0770, AID_MEDIA_RW, AID_MEDIA_RW) != 0) {
+ SLOGW("fs_prepare_dir failed: %s", strerror(errno));
+ return -errno;
+ }
+
+ return OK;
+}
+
+status_t PublicVolume::doMount() {
+ if (Fat::check(mDevPath.c_str())) {
+ SLOGE("Failed filesystem check; not mounting");
+ return -EIO;
+ }
+
+ if (fs_prepare_dir(mRawPath.c_str(), 0770, AID_MEDIA_RW, AID_MEDIA_RW)) {
+ SLOGE("Failed to create mount point %s: %s", mRawPath.c_str(), strerror(errno));
+ return -errno;
+ }
+ if (fs_prepare_dir(mFusePath.c_str(), 0770, AID_MEDIA_RW, AID_MEDIA_RW)) {
+ SLOGE("Failed to create mount point %s: %s", mFusePath.c_str(), strerror(errno));
+ return -errno;
+ }
+
+ if (Fat::doMount(mDevPath.c_str(), mRawPath.c_str(), false, false, false,
+ AID_MEDIA_RW, AID_MEDIA_RW, 0007, true)) {
+ SLOGE("Failed to mount %s: %s", mDevPath.c_str(), strerror(errno));
+ return -EIO;
+ }
+
+ if (!(mFusePid = fork())) {
+ if (mPrimary) {
+ if (execl(kFusePath,
+ "-u", "1023", // AID_MEDIA_RW
+ "-g", "1023", // AID_MEDIA_RW
+ "-d",
+ mRawPath.c_str(),
+ mFusePath.c_str())) {
+ SLOGE("Failed to exec: %s", strerror(errno));
+ }
+ } else {
+ if (execl(kFusePath,
+ "-u", "1023", // AID_MEDIA_RW
+ "-g", "1023", // AID_MEDIA_RW
+ "-w", "1023", // AID_MEDIA_RW
+ "-d",
+ mRawPath.c_str(),
+ mFusePath.c_str())) {
+ SLOGE("Failed to exec: %s", strerror(errno));
+ }
+ }
+
+ _exit(1);
+ }
+
+ if (mFusePid == -1) {
+ SLOGE("Failed to fork: %s", strerror(errno));
+ return -errno;
+ }
+
+ return OK;
+}
+
+status_t PublicVolume::doUnmount() {
+ if (mFusePid > 0) {
+ kill(mFusePid, SIGTERM);
+ TEMP_FAILURE_RETRY(waitpid(mFusePid, nullptr, 0));
+ mFusePid = 0;
+ }
+
+ ForceUnmount(mFusePath);
+ ForceUnmount(mRawPath);
+
+ TEMP_FAILURE_RETRY(unlink(mRawPath.c_str()));
+ TEMP_FAILURE_RETRY(unlink(mFusePath.c_str()));
+
+ return OK;
+}
+
+status_t PublicVolume::doFormat() {
+ if (Fat::format(mDevPath.c_str(), 0, true)) {
+ SLOGE("Failed to format: %s", strerror(errno));
+ return -errno;
+ }
+ return OK;
+}
+
+status_t PublicVolume::bindUser(userid_t user) {
+ return bindUserInternal(user, true);
+}
+
+status_t PublicVolume::unbindUser(userid_t user) {
+ return bindUserInternal(user, false);
+}
+
+status_t PublicVolume::bindUserInternal(userid_t user, bool bind) {
+ if (mPrimary) {
+ if (user == 0) {
+ std::string path(StringPrintf("%s/%ud/primary", kUserMountPath, user));
+ if (bind) {
+ mountBind(mFusePath, path);
+ } else {
+ unmountBind(path);
+ }
+ } else {
+ // Public volumes are only visible to owner when primary
+ // storage, so we don't mount for secondary users.
+ }
+ } else {
+ std::string path(StringPrintf("%s/%ud/public_%ud:%ud", kUserMountPath, user,
+ major(mDevice), minor(mDevice)));
+ if (bind) {
+ mountBind(mFusePath, path);
+ } else {
+ unmountBind(path);
+ }
+
+ if (user != 0) {
+ // To prevent information leakage between users, only owner
+ // has access to the Android directory
+ path += "/Android";
+ if (bind) {
+ if (::mount("tmpfs", path.c_str(), "tmpfs", MS_NOSUID, "mode=0000")) {
+ SLOGE("Failed to protect secondary path %s: %s",
+ path.c_str(), strerror(errno));
+ return -errno;
+ }
+ } else {
+ ForceUnmount(path);
+ }
+ }
+ }
+
+ return OK;
+}
+
+void PublicVolume::setPrimary(bool primary) {
+ if (getState() != VolumeState::kUnmounted) {
+ SLOGE("Primary state change requires %s to be unmounted", getId().c_str());
+ return;
+ }
+
+ mPrimary = primary;
+}
+
+} // namespace vold
+} // namespace android