Add a new "virtual disk" feature.
It's extremely difficult to test storage related logic on devices
that don't have physical SD card slots. So to support better
debugging and testing, add a new "virtual disk" feature which mounts
a 512MB file through loop device.
It relies on the kernel having the "loop.max_part" value set to
something other than 0 via the boot command line, since that allows
all the existing partition logic to fall into place.
Bug: 34903607
Test: builds, boots, virtual disk works
Change-Id: I04c5b33e37319d867542985a56b7999a9b7cf35d
diff --git a/Disk.cpp b/Disk.cpp
index 6562d96..8e58be0 100644
--- a/Disk.cpp
+++ b/Disk.cpp
@@ -47,8 +47,10 @@
static const char* kSgdiskPath = "/system/bin/sgdisk";
static const char* kSgdiskToken = " \t\n";
+static const char* kSysfsLoopMaxMinors = "/sys/module/loop/parameters/max_part";
static const char* kSysfsMmcMaxMinors = "/sys/module/mmcblk/parameters/perdev_minors";
+static const unsigned int kMajorBlockLoop = 7;
static const unsigned int kMajorBlockScsiA = 8;
static const unsigned int kMajorBlockScsiB = 65;
static const unsigned int kMajorBlockScsiC = 66;
@@ -229,6 +231,10 @@
unsigned int majorId = major(mDevice);
switch (majorId) {
+ case kMajorBlockLoop: {
+ mLabel = "Virtual";
+ break;
+ }
case kMajorBlockScsiA: case kMajorBlockScsiB: case kMajorBlockScsiC: case kMajorBlockScsiD:
case kMajorBlockScsiE: case kMajorBlockScsiF: case kMajorBlockScsiG: case kMajorBlockScsiH:
case kMajorBlockScsiI: case kMajorBlockScsiJ: case kMajorBlockScsiK: case kMajorBlockScsiL:
@@ -534,6 +540,14 @@
// Figure out maximum partition devices supported
unsigned int majorId = major(mDevice);
switch (majorId) {
+ case kMajorBlockLoop: {
+ std::string tmp;
+ if (!ReadFileToString(kSysfsLoopMaxMinors, &tmp)) {
+ LOG(ERROR) << "Failed to read max minors";
+ return -errno;
+ }
+ return atoi(tmp.c_str());
+ }
case kMajorBlockScsiA: case kMajorBlockScsiB: case kMajorBlockScsiC: case kMajorBlockScsiD:
case kMajorBlockScsiE: case kMajorBlockScsiF: case kMajorBlockScsiG: case kMajorBlockScsiH:
case kMajorBlockScsiI: case kMajorBlockScsiJ: case kMajorBlockScsiK: case kMajorBlockScsiL:
diff --git a/Loop.cpp b/Loop.cpp
index 1127817..7e243de 100644
--- a/Loop.cpp
+++ b/Loop.cpp
@@ -32,12 +32,19 @@
#include <cutils/log.h>
+#include <android-base/logging.h>
+#include <android-base/stringprintf.h>
+#include <android-base/unique_fd.h>
+
#include <sysutils/SocketClient.h>
#include "Loop.h"
#include "Asec.h"
#include "VoldUtil.h"
#include "sehandle.h"
+using android::base::StringPrintf;
+using android::base::unique_fd;
+
int Loop::dumpState(SocketClient *c) {
int i;
int fd;
@@ -229,6 +236,40 @@
return 0;
}
+int Loop::create(const std::string& target, std::string& out_device) {
+ unique_fd ctl_fd(open("/dev/loop-control", O_RDWR));
+ if (ctl_fd.get() == -1) {
+ PLOG(ERROR) << "Failed to open loop-control";
+ return -errno;
+ }
+
+ int num = ioctl(ctl_fd.get(), LOOP_CTL_GET_FREE);
+ if (num == -1) {
+ PLOG(ERROR) << "Failed LOOP_CTL_GET_FREE";
+ return -errno;
+ }
+
+ out_device = StringPrintf("/dev/block/loop%d", num);
+
+ unique_fd target_fd(open(target.c_str(), O_RDWR));
+ if (target_fd.get() == -1) {
+ PLOG(ERROR) << "Failed to open " << target;
+ return -errno;
+ }
+ unique_fd device_fd(open(out_device.c_str(), O_RDWR));
+ if (device_fd.get() == -1) {
+ PLOG(ERROR) << "Failed to open " << out_device;
+ return -errno;
+ }
+
+ if (ioctl(device_fd.get(), LOOP_SET_FD, target_fd.get()) == -1) {
+ PLOG(ERROR) << "Failed to LOOP_SET_FD";
+ return -errno;
+ }
+
+ return 0;
+}
+
int Loop::destroyByDevice(const char *loopDevice) {
int device_fd;
@@ -254,20 +295,37 @@
}
int Loop::createImageFile(const char *file, unsigned long numSectors) {
- int fd;
+ int res = 0;
- if ((fd = creat(file, 0600)) < 0) {
- SLOGE("Error creating imagefile (%s)", strerror(errno));
- return -1;
+ char* secontext = nullptr;
+ if (sehandle) {
+ if (!selabel_lookup(sehandle, &secontext, file, S_IFREG)) {
+ setfscreatecon(secontext);
+ }
}
- if (ftruncate(fd, numSectors * 512) < 0) {
- SLOGE("Error truncating imagefile (%s)", strerror(errno));
- close(fd);
- return -1;
+ unique_fd fd(creat(file, 0600));
+ if (fd.get() == -1) {
+ PLOG(ERROR) << "Failed to create image " << file;
+ res = -errno;
+ goto done;
}
- close(fd);
- return 0;
+
+ if (fallocate(fd.get(), 0, 0, numSectors * 512) == -1) {
+ PLOG(WARNING) << "Failed to fallocate; falling back to ftruncate";
+ if (ftruncate(fd, numSectors * 512) == -1) {
+ PLOG(ERROR) << "Failed to ftruncate";
+ res = -errno;
+ }
+ }
+
+done:
+ if (secontext) {
+ setfscreatecon(nullptr);
+ freecon(secontext);
+ }
+
+ return res;
}
int Loop::resizeImageFile(const char *file, unsigned long numSectors) {
diff --git a/Loop.h b/Loop.h
index 72130b0..5d8f427 100644
--- a/Loop.h
+++ b/Loop.h
@@ -17,6 +17,7 @@
#ifndef _LOOP_H
#define _LOOP_H
+#include <string>
#include <unistd.h>
#include <linux/loop.h>
@@ -29,6 +30,7 @@
static int lookupActive(const char *id, char *buffer, size_t len);
static int lookupInfo(const char *loopDevice, struct asec_superblock *sb, unsigned long *nr_sec);
static int create(const char *id, const char *loopFile, char *loopDeviceBuffer, size_t len);
+ static int create(const std::string& file, std::string& out_device);
static int destroyByDevice(const char *loopDevice);
static int destroyByFile(const char *loopFile);
static int createImageFile(const char *file, unsigned long numSectors);
diff --git a/VolumeManager.cpp b/VolumeManager.cpp
index 40e3921..a67c8ec 100644
--- a/VolumeManager.cpp
+++ b/VolumeManager.cpp
@@ -88,7 +88,13 @@
*/
const char *VolumeManager::LOOPDIR = "/mnt/obb";
-static const char* kUserMountPath = "/mnt/user";
+static const char* kPathUserMount = "/mnt/user";
+static const char* kPathVirtualDisk = "/data/misc/vold/virtual_disk";
+
+static const char* kPropVirtualDisk = "persist.sys.virtual_disk";
+
+/* 512MiB is large enough for testing purposes */
+static const unsigned int kSizeVirtualDisk = 536870912;
static const unsigned int kMajorBlockMmc = 179;
static const unsigned int kMajorBlockExperimentalMin = 240;
@@ -249,6 +255,55 @@
return buffer;
}
+int VolumeManager::updateVirtualDisk() {
+ if (property_get_bool(kPropVirtualDisk, false)) {
+ if (access(kPathVirtualDisk, F_OK) != 0) {
+ Loop::createImageFile(kPathVirtualDisk, kSizeVirtualDisk / 512);
+ }
+
+ if (mVirtualDisk == nullptr) {
+ if (Loop::create(kPathVirtualDisk, mVirtualDiskPath) != 0) {
+ LOG(ERROR) << "Failed to create virtual disk";
+ return -1;
+ }
+
+ struct stat buf;
+ if (stat(mVirtualDiskPath.c_str(), &buf) < 0) {
+ PLOG(ERROR) << "Failed to stat " << mVirtualDiskPath;
+ return -1;
+ }
+
+ auto disk = new android::vold::Disk("virtual", buf.st_rdev, "virtual",
+ android::vold::Disk::Flags::kAdoptable | android::vold::Disk::Flags::kSd);
+ disk->create();
+ mVirtualDisk = std::shared_ptr<android::vold::Disk>(disk);
+ mDisks.push_back(mVirtualDisk);
+ }
+ } else {
+ if (mVirtualDisk != nullptr) {
+ dev_t device = mVirtualDisk->getDevice();
+
+ auto i = mDisks.begin();
+ while (i != mDisks.end()) {
+ if ((*i)->getDevice() == device) {
+ (*i)->destroy();
+ i = mDisks.erase(i);
+ } else {
+ ++i;
+ }
+ }
+
+ Loop::destroyByDevice(mVirtualDiskPath.c_str());
+ mVirtualDisk = nullptr;
+ }
+
+ if (access(kPathVirtualDisk, F_OK) == 0) {
+ unlink(kPathVirtualDisk);
+ }
+ }
+ return 0;
+}
+
int VolumeManager::setDebug(bool enable) {
mDebug = enable;
return 0;
@@ -266,6 +321,9 @@
new android::vold::EmulatedVolume("/data/media"));
mInternalEmulated->create();
+ // Consider creating a virtual disk
+ updateVirtualDisk();
+
return 0;
}
@@ -455,7 +513,7 @@
// Note that sometimes the system will spin up processes from Zygote
// before actually starting the user, so we're okay if Zygote
// already created this directory.
- std::string path(StringPrintf("%s/%d", kUserMountPath, userId));
+ std::string path(StringPrintf("%s/%d", kPathUserMount, userId));
fs_prepare_dir(path.c_str(), 0755, AID_ROOT, AID_ROOT);
mStartedUsers.insert(userId);
@@ -634,6 +692,7 @@
disk->destroy();
disk->create();
}
+ updateVirtualDisk();
mAddedUsers.clear();
mStartedUsers.clear();
return 0;
diff --git a/VolumeManager.h b/VolumeManager.h
index dd9f09d..796a91d 100644
--- a/VolumeManager.h
+++ b/VolumeManager.h
@@ -176,6 +176,7 @@
int unmountLoopImage(const char *containerId, const char *loopId,
const char *fileName, const char *mountPoint, bool force);
+ int updateVirtualDisk();
int setDebug(bool enable);
void setBroadcaster(SocketListener *sl) { mBroadcaster = sl; }
@@ -211,6 +212,8 @@
std::unordered_map<userid_t, int> mAddedUsers;
std::unordered_set<userid_t> mStartedUsers;
+ std::string mVirtualDiskPath;
+ std::shared_ptr<android::vold::Disk> mVirtualDisk;
std::shared_ptr<android::vold::VolumeBase> mInternalEmulated;
std::shared_ptr<android::vold::VolumeBase> mPrimary;
};