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Merge "adb: use /system/bin/remount command"

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am: d458066bc7

Change-Id: I0276c6488dd5d57475e6b73cf1fef5a00a2e75b8
This commit is contained in:
Mark Salyzyn 2019-03-04 14:41:21 -08:00 committed by android-build-merger
commit bc0887add7
4 changed files with 75 additions and 314 deletions
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8
adb/Android.bp
View file

@ -402,6 +402,14 @@ cc_library {
"liblog",
],
product_variables: {
debuggable: {
required: [
"remount",
],
},
},
target: {
android: {
srcs: [

366
adb/daemon/remount_service.cpp
View file

@ -14,339 +14,81 @@
* limitations under the License.
*/
#define TRACE_TAG ADB
#include "sysdeps.h"
#include <errno.h>
#include <fcntl.h>
#include <mntent.h>
#include <spawn.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mount.h>
#include <sys/statvfs.h>
#include <sys/vfs.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <memory>
#include <set>
#include <string>
#include <vector>
#include <android-base/file.h>
#include <android-base/properties.h>
#include <bootloader_message/bootloader_message.h>
#include <cutils/android_reboot.h>
#include <fs_mgr.h>
#include <fs_mgr_overlayfs.h>
#include "adb.h"
#include "adb_io.h"
#include "adb_unique_fd.h"
#include "adb_utils.h"
#include "set_verity_enable_state_service.h"
using android::base::Realpath;
using android::fs_mgr::Fstab;
using android::fs_mgr::ReadDefaultFstab;
// Returns the last device used to mount a directory in /proc/mounts.
// This will find overlayfs entry where upperdir=lowerdir, to make sure
// remount is associated with the correct directory.
static std::string find_proc_mount(const char* dir) {
std::unique_ptr<FILE, int(*)(FILE*)> fp(setmntent("/proc/mounts", "r"), endmntent);
std::string mnt_fsname;
if (!fp) return mnt_fsname;
// dir might be a symlink, e.g., /product -> /system/product in GSI.
std::string canonical_path;
if (!Realpath(dir, &canonical_path)) {
PLOG(ERROR) << "Realpath failed: " << dir;
}
mntent* e;
while ((e = getmntent(fp.get())) != nullptr) {
if (canonical_path == e->mnt_dir) {
mnt_fsname = e->mnt_fsname;
}
}
return mnt_fsname;
}
// Returns the device used to mount a directory in the fstab.
static std::string find_fstab_mount(const char* dir) {
Fstab fstab;
if (!ReadDefaultFstab(&fstab)) {
return "";
}
auto entry = std::find_if(fstab.begin(), fstab.end(),
[&dir](const auto& entry) { return entry.mount_point == dir; });
if (entry == fstab.end()) {
return "";
}
if (entry->fs_mgr_flags.logical) {
fs_mgr_update_logical_partition(&(*entry));
}
return entry->blk_device;
}
// The proc entry for / is full of lies, so check fstab instead.
// /proc/mounts lists rootfs and /dev/root, neither of which is what we want.
static std::string find_mount(const char* dir, bool is_root) {
if (is_root) {
return find_fstab_mount(dir);
} else {
return find_proc_mount(dir);
}
}
bool dev_is_overlayfs(const std::string& dev) {
return (dev == "overlay") || (dev == "overlayfs");
}
bool make_block_device_writable(const std::string& dev) {
if (dev_is_overlayfs(dev)) return true;
int fd = unix_open(dev, O_RDONLY | O_CLOEXEC);
if (fd == -1) {
return false;
}
int OFF = 0;
bool result = (ioctl(fd, BLKROSET, &OFF) != -1);
unix_close(fd);
return result;
}
static bool can_unshare_blocks(int fd, const char* dev) {
const char* E2FSCK_BIN = "/system/bin/e2fsck";
if (access(E2FSCK_BIN, X_OK)) {
WriteFdFmt(fd, "e2fsck is not available, cannot undo deduplication on %s\n", dev);
return false;
}
pid_t child;
char* env[] = {nullptr};
const char* argv[] = {E2FSCK_BIN, "-n", "-E", "unshare_blocks", dev, nullptr};
if (posix_spawn(&child, E2FSCK_BIN, nullptr, nullptr, const_cast<char**>(argv), env)) {
WriteFdFmt(fd, "failed to e2fsck to check deduplication: %s\n", strerror(errno));
return false;
}
int status = 0;
int ret = TEMP_FAILURE_RETRY(waitpid(child, &status, 0));
if (ret < 0) {
WriteFdFmt(fd, "failed to get e2fsck status: %s\n", strerror(errno));
return false;
}
if (!WIFEXITED(status)) {
WriteFdFmt(fd, "e2fsck exited abnormally with status %d\n", status);
return false;
}
int rc = WEXITSTATUS(status);
if (rc != 0) {
WriteFdFmt(fd,
"%s is deduplicated, and an e2fsck check failed. It might not "
"have enough free-space to be remounted as writable.\n",
dev);
return false;
}
return true;
}
static unsigned long get_mount_flags(int fd, const char* dir) {
struct statvfs st_vfs;
if (statvfs(dir, &st_vfs) == -1) {
// Even though we could not get the original mount flags, assume that
// the mount was originally read-only.
WriteFdFmt(fd, "statvfs of the %s mount failed: %s.\n", dir, strerror(errno));
return MS_RDONLY;
}
return st_vfs.f_flag;
}
static bool remount_partition(int fd, const char* dir) {
if (!directory_exists(dir)) {
return true;
}
bool is_root = strcmp(dir, "/") == 0;
if (is_root && dev_is_overlayfs(find_mount("/system", false))) {
dir = "/system";
is_root = false;
}
std::string dev = find_mount(dir, is_root);
if (is_root && dev.empty()) {
// The fstab entry will be /system if the device switched roots during
// first-stage init.
dev = find_mount("/system", true);
}
// Even if the device for the root is not found, we still try to remount it
// as rw. This typically only happens when running Android in a container:
// the root will almost always be in a loop device, which is dynamic, so
// it's not convenient to put in the fstab.
if (dev.empty() && !is_root) {
return true;
}
if (!dev.empty() && !make_block_device_writable(dev)) {
WriteFdFmt(fd, "remount of %s failed; couldn't make block device %s writable: %s\n",
dir, dev.c_str(), strerror(errno));
return false;
}
unsigned long remount_flags = get_mount_flags(fd, dir);
remount_flags &= ~MS_RDONLY;
remount_flags |= MS_REMOUNT;
if (mount(dev.c_str(), dir, "none", remount_flags | MS_BIND, nullptr) == -1) {
// This is useful for cases where the superblock is already marked as
// read-write, but the mount itself is read-only, such as containers
// where the remount with just MS_REMOUNT is forbidden by the kernel.
WriteFdFmt(fd, "remount of the %s mount failed: %s.\n", dir, strerror(errno));
return false;
}
if (mount(dev.c_str(), dir, "none", MS_REMOUNT, nullptr) == -1) {
WriteFdFmt(fd, "remount of the %s superblock failed: %s\n", dir, strerror(errno));
return false;
}
return true;
}
static void reboot_for_remount(int fd, bool need_fsck) {
std::string reboot_cmd = "reboot";
if (need_fsck) {
const std::vector<std::string> options = {"--fsck_unshare_blocks"};
std::string err;
if (!write_bootloader_message(options, &err)) {
WriteFdFmt(fd, "Failed to set bootloader message: %s\n", err.c_str());
return;
}
WriteFdExactly(fd,
"The device will now reboot to recovery and attempt "
"un-deduplication.\n");
reboot_cmd = "reboot,recovery";
}
sync();
android::base::SetProperty(ANDROID_RB_PROPERTY, reboot_cmd.c_str());
}
static void try_unmount_bionic(int fd) {
static constexpr const char* kBionic = "/bionic";
struct statfs buf;
if (statfs(kBionic, &buf) == -1) {
WriteFdFmt(fd, "statfs of the %s mount failed: %s.\n", kBionic, strerror(errno));
return;
}
if (buf.f_flags & ST_RDONLY) {
// /bionic is on a read-only partition; can happen for
// non-system-as-root-devices. Don' try to unmount.
return;
}
// Success/Fail of the actual remount will be reported by the function.
remount_partition(fd, kBionic);
return;
}
void remount_service(unique_fd fd, const std::string& cmd) {
bool user_requested_reboot = cmd == "-R";
static constexpr char remount_cmd[] = "/system/bin/remount";
static constexpr char remount_failed[] = "remount failed\n";
if (getuid() != 0) {
WriteFdExactly(fd.get(), "Not running as root. Try \"adb root\" first.\n");
WriteFdExactly(fd.get(), remount_failed);
return;
}
bool system_verified = !(android::base::GetProperty("partition.system.verified", "").empty());
bool vendor_verified = !(android::base::GetProperty("partition.vendor.verified", "").empty());
std::vector<std::string> partitions{"/", "/odm", "/oem", "/product_services",
"/product", "/vendor"};
if (system_verified || vendor_verified) {
// Disable verity automatically (reboot will be required).
set_verity_enabled_state_service(unique_fd(dup(fd.get())), false);
// If overlayfs is not supported, we try and remount or set up
// un-deduplication. If it is supported, we can go ahead and wait for
// a reboot.
if (fs_mgr_overlayfs_valid() != OverlayfsValidResult::kNotSupported) {
if (user_requested_reboot) {
if (android::base::SetProperty(ANDROID_RB_PROPERTY, "reboot")) {
WriteFdExactly(fd.get(), "rebooting device\n");
} else {
WriteFdExactly(fd.get(), "reboot failed\n");
}
}
return;
}
} else if (fs_mgr_overlayfs_setup()) {
// If we can use overlayfs, lets get it in place first before we
// struggle with determining deduplication operations.
Fstab fstab;
if (ReadDefaultFstab(&fstab) && fs_mgr_overlayfs_mount_all(&fstab)) {
WriteFdExactly(fd.get(), "overlayfs mounted\n");
}
}
// If overlayfs is supported, we don't bother trying to un-deduplicate
// partitions.
std::set<std::string> dedup;
if (fs_mgr_overlayfs_valid() == OverlayfsValidResult::kNotSupported) {
// Find partitions that are deduplicated, and can be un-deduplicated.
for (const auto& part : partitions) {
auto partition = part;
if ((part == "/") && !find_mount("/system", false).empty()) partition = "/system";
std::string dev = find_mount(partition.c_str(), partition == "/");
if (dev.empty() || !fs_mgr_has_shared_blocks(partition, dev)) {
continue;
}
if (can_unshare_blocks(fd.get(), dev.c_str())) {
dedup.emplace(partition);
}
}
// Reboot now if the user requested it (and an operation needs a reboot).
if (user_requested_reboot) {
if (!dedup.empty()) {
reboot_for_remount(fd.get(), !dedup.empty());
return;
}
WriteFdExactly(fd.get(), "No reboot needed, skipping -R.\n");
}
}
bool success = true;
for (const auto& partition : partitions) {
// Don't try to remount partitions that need an fsck in recovery.
if (dedup.count(partition)) {
continue;
}
success &= remount_partition(fd.get(), partition.c_str());
}
if (!dedup.empty()) {
WriteFdExactly(fd.get(),
"The following partitions are deduplicated and cannot "
"yet be remounted:\n");
for (const std::string& name : dedup) {
WriteFdFmt(fd.get(), " %s\n", name.c_str());
}
WriteFdExactly(fd.get(),
"To reboot and un-deduplicate the listed partitions, "
"please retry with adb remount -R.\n");
if (system_verified || vendor_verified) {
WriteFdExactly(fd.get(), "Note: verity will be automatically disabled after reboot.\n");
}
auto pid = vfork();
if (pid < 0) {
WriteFdFmt(fd.get(), "Failed to fork to %s: %s\n", remount_cmd, strerror(errno));
WriteFdExactly(fd.get(), remount_failed);
return;
}
try_unmount_bionic(fd.get());
if (pid == 0) {
// child side of the fork
fcntl(fd.get(), F_SETFD, 0);
dup2(fd.get(), STDIN_FILENO);
dup2(fd.get(), STDOUT_FILENO);
dup2(fd.get(), STDERR_FILENO);
if (!success) {
WriteFdExactly(fd.get(), "remount failed\n");
} else {
WriteFdExactly(fd.get(), "remount succeeded\n");
execl(remount_cmd, remount_cmd, cmd.empty() ? nullptr : cmd.c_str(), nullptr);
_exit(-errno ?: 42);
}
int wstatus = 0;
auto ret = waitpid(pid, &wstatus, 0);
if (ret == -1) {
WriteFdFmt(fd.get(), "Failed to wait for %s: %s\n", remount_cmd, strerror(errno));
goto err;
}
if (ret != pid) {
WriteFdFmt(fd.get(), "pid %d and waitpid return %d do not match for %s\n",
static_cast<int>(pid), static_cast<int>(ret), remount_cmd);
goto err;
}
if (WIFSIGNALED(wstatus)) {
WriteFdFmt(fd.get(), "%s terminated with signal %s\n", remount_cmd,
strsignal(WTERMSIG(wstatus)));
goto err;
}
if (!WIFEXITED(wstatus)) {
WriteFdFmt(fd.get(), "%s stopped with status 0x%x\n", remount_cmd, wstatus);
goto err;
}
if (WEXITSTATUS(wstatus)) {
WriteFdFmt(fd.get(), "%s exited with status %d\n", remount_cmd,
static_cast<signed char>(WEXITSTATUS(wstatus)));
goto err;
}
WriteFdExactly(fd.get(), "remount succeeded\n");
return;
err:
WriteFdExactly(fd.get(), remount_failed);
}

1
adb/daemon/remount_service.h
View file

@ -21,6 +21,5 @@
#include "adb_unique_fd.h"
#if defined(__ANDROID__)
bool make_block_device_writable(const std::string&);
void remount_service(unique_fd, const std::string&);
#endif

14
adb/daemon/set_verity_enable_state_service.cpp
View file

@ -25,6 +25,7 @@
#include <libavb_user/libavb_user.h>
#include <stdarg.h>
#include <stdio.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <android-base/properties.h>
@ -37,7 +38,6 @@
#include "adb.h"
#include "adb_io.h"
#include "adb_unique_fd.h"
#include "remount_service.h"
#include "fec/io.h"
@ -51,6 +51,18 @@ void suggest_run_adb_root(int fd) {
if (getuid() != 0) WriteFdExactly(fd, "Maybe run adb root?\n");
}
static bool make_block_device_writable(const std::string& dev) {
int fd = unix_open(dev, O_RDONLY | O_CLOEXEC);
if (fd == -1) {
return false;
}
int OFF = 0;
bool result = (ioctl(fd, BLKROSET, &OFF) != -1);
unix_close(fd);
return result;
}
/* Turn verity on/off */
static bool set_verity_enabled_state(int fd, const char* block_device, const char* mount_point,
bool enable) {