Mount /dev/fuse on /mnt/user/<userid>/<volumeid>
Since system_server cannot mount devices by itself,
add a binder interface to vold that system_server
can call to initiate this mount when required.
BUG: 135341433
Test: manual
Test: atest --test-mapping packages/providers/MediaProvider
Test: ExternalStorageHostTest DownloadProviderTests
Change-Id: If4fd02a1f1a8d921a3f96783d8c73e085c5b7ca1
diff --git a/model/EmulatedVolume.cpp b/model/EmulatedVolume.cpp
index 552fe2f..ca314ef 100644
--- a/model/EmulatedVolume.cpp
+++ b/model/EmulatedVolume.cpp
@@ -15,10 +15,13 @@
*/
#include "EmulatedVolume.h"
+
+#include "AppFuseUtil.h"
#include "Utils.h"
#include "VolumeManager.h"
#include <android-base/logging.h>
+#include <android-base/properties.h>
#include <android-base/stringprintf.h>
#include <cutils/fs.h>
#include <private/android_filesystem_config.h>
@@ -81,7 +84,22 @@
dev_t before = GetDevice(mFuseFull);
+ bool isFuse = base::GetBoolProperty(kPropFuse, false);
+
+ if (isFuse) {
+ LOG(INFO) << "Mounting emulated fuse volume";
+ int fd = -1;
+ int result = MountUserFuse(getMountUserId(), label, &fd);
+ if (result != 0) {
+ PLOG(ERROR) << "Failed to mount emulated fuse volume";
+ return -result;
+ }
+ setDeviceFd(fd);
+ return OK;
+ }
+
if (!(mFusePid = fork())) {
+ LOG(INFO) << "Executing sdcardfs";
// clang-format off
if (execl(kFusePath, kFusePath,
"-u", "1023", // AID_MEDIA_RW
@@ -131,6 +149,31 @@
// ENOTCONN until the unmount completes. This is an exotic and unusual
// error code and might cause broken behaviour in applications.
KillProcessesUsingPath(getPath());
+
+ bool isFuse = base::GetBoolProperty(kPropFuse, false);
+ if (isFuse) {
+ // We could have migrated storage to an adopted private volume, so always
+ // call primary storage "emulated" to avoid media rescans.
+ std::string label = mLabel;
+ if (getMountFlags() & MountFlags::kPrimary) {
+ label = "emulated";
+ }
+ std::string path(StringPrintf("/mnt/user/%d/%s", getMountUserId(), label.c_str()));
+ status_t result = ForceUnmount(path);
+ if (result != OK) {
+ // TODO(135341433): MNT_DETACH is needed for fuse because umount2 can fail with EBUSY.
+ // Figure out why we get EBUSY and remove this special casing if possible.
+ if (!umount2(path.c_str(), UMOUNT_NOFOLLOW | MNT_DETACH) || errno == EINVAL ||
+ errno == ENOENT) {
+ PLOG(INFO) << "ForceUnmount failed on emulated fuse volume";
+ }
+ }
+
+ rmdir(path.c_str());
+ setDeviceFd(-1);
+ return OK;
+ }
+
ForceUnmount(mFuseDefault);
ForceUnmount(mFuseRead);
ForceUnmount(mFuseWrite);
diff --git a/model/PublicVolume.cpp b/model/PublicVolume.cpp
index 0a6b351..2c0b4cc 100644
--- a/model/PublicVolume.cpp
+++ b/model/PublicVolume.cpp
@@ -15,6 +15,8 @@
*/
#include "PublicVolume.h"
+
+#include "AppFuseUtil.h"
#include "Utils.h"
#include "VolumeManager.h"
#include "fs/Exfat.h"
@@ -167,6 +169,20 @@
dev_t before = GetDevice(mFuseFull);
+ bool isFuse = base::GetBoolProperty(kPropFuse, false);
+
+ if (isFuse) {
+ LOG(INFO) << "Mounting public fuse volume";
+ int fd = -1;
+ int result = MountUserFuse(getMountUserId(), stableName, &fd);
+ if (result != 0) {
+ LOG(ERROR) << "Failed to mount public fuse volume";
+ return -result;
+ }
+ setDeviceFd(fd);
+ return OK;
+ }
+
if (!(mFusePid = fork())) {
if (getMountFlags() & MountFlags::kPrimary) {
// clang-format off
@@ -229,6 +245,30 @@
// error code and might cause broken behaviour in applications.
KillProcessesUsingPath(getPath());
+ bool isFuse = base::GetBoolProperty(kPropFuse, false);
+ if (isFuse) {
+ // Use UUID as stable name, if available
+ std::string stableName = getId();
+ if (!mFsUuid.empty()) {
+ stableName = mFsUuid;
+ }
+
+ std::string path(StringPrintf("/mnt/user/%d/%s", getMountUserId(), stableName.c_str()));
+ status_t result = ForceUnmount(path);
+ if (result != OK) {
+ // TODO(135341433): MNT_DETACH is needed for fuse because umount2 can fail with EBUSY.
+ // Figure out why we get EBUSY and remove this special casing if possible.
+ if (!umount2(path.c_str(), UMOUNT_NOFOLLOW | MNT_DETACH) || errno == EINVAL ||
+ errno == ENOENT) {
+ PLOG(INFO) << "ForceUnmount failed on public fuse volume";
+ }
+ }
+
+ rmdir(path.c_str());
+ setDeviceFd(-1);
+ return OK;
+ }
+
ForceUnmount(kAsecPath);
ForceUnmount(mFuseDefault);
diff --git a/model/VolumeBase.cpp b/model/VolumeBase.cpp
index ffc7900..fa007ad 100644
--- a/model/VolumeBase.cpp
+++ b/model/VolumeBase.cpp
@@ -143,6 +143,16 @@
return OK;
}
+status_t VolumeBase::setDeviceFd(int deviceFd) {
+ if ((mState != State::kChecking)) {
+ LOG(WARNING) << getId() << " device fd change requires state checking";
+ return -EBUSY;
+ }
+
+ mDeviceFd.reset(deviceFd);
+ return OK;
+}
+
android::sp<android::os::IVoldListener> VolumeBase::getListener() const {
if (mSilent) {
return nullptr;
diff --git a/model/VolumeBase.h b/model/VolumeBase.h
index 53eeb6f..fa9eee4 100644
--- a/model/VolumeBase.h
+++ b/model/VolumeBase.h
@@ -87,6 +87,7 @@
State getState() const { return mState; }
const std::string& getPath() const { return mPath; }
const std::string& getInternalPath() const { return mInternalPath; }
+ int getDeviceFd() const { return dup(mDeviceFd.get()); }
status_t setDiskId(const std::string& diskId);
status_t setPartGuid(const std::string& partGuid);
@@ -121,6 +122,7 @@
status_t setId(const std::string& id);
status_t setPath(const std::string& path);
status_t setInternalPath(const std::string& internalPath);
+ status_t setDeviceFd(int deviceFd);
android::sp<android::os::IVoldListener> getListener() const;
@@ -147,6 +149,8 @@
std::string mInternalPath;
/* Flag indicating that volume should emit no events */
bool mSilent;
+ /* The filedescriptor for the fuse device, if the volume uses fuse, or -1 otherwise */
+ android::base::unique_fd mDeviceFd;
/* Volumes stacked on top of this volume */
std::list<std::shared_ptr<VolumeBase>> mVolumes;