init: chroot from recovery to /first_stage_ramdisk
When using the recovery image as a trampoline to boot the system,
first chroot from the recovery image to /first_stage_ramdisk, to
minimize differences between these two boot paths.
Primary motivation is due to the fact that the basename of each mount
point is used by device-manager to name its nodes, and the previous
code that created used /system_recovery_mount as the mount point for
system.img broke AVB. Instead of hacking around that issue, this
change unified mounting for the recovery trampoline and true first
stage ramdisk paths.
Bug: 114062208
Test: AVB works with blueline_mainline
Change-Id: Iffb154962b6e160150917e068f1e7d0bf7cb84e7
diff --git a/init/first_stage_mount.cpp b/init/first_stage_mount.cpp
index eb86eb0..a4ded92 100644
--- a/init/first_stage_mount.cpp
+++ b/init/first_stage_mount.cpp
@@ -17,6 +17,7 @@
#include "first_stage_mount.h"
#include <stdlib.h>
+#include <sys/mount.h>
#include <unistd.h>
#include <chrono>
@@ -122,18 +123,8 @@
return is_android_dt_value_expected("vbmeta/compatible", "android,vbmeta");
}
-static bool ForceNormalBoot() {
- static bool force_normal_boot = []() {
- std::string cmdline;
- android::base::ReadFileToString("/proc/cmdline", &cmdline);
- return cmdline.find("androidboot.force_normal_boot=1") != std::string::npos;
- }();
-
- return force_normal_boot;
-}
-
static bool IsRecoveryMode() {
- return !ForceNormalBoot() && access("/system/bin/recovery", F_OK) == 0;
+ return access("/system/bin/recovery", F_OK) == 0;
}
// Class Definitions
@@ -371,16 +362,11 @@
[](const auto& rec) { return rec->mount_point == "/system"s; });
if (system_partition != mount_fstab_recs_.end()) {
- if (ForceNormalBoot()) {
- free((*system_partition)->mount_point);
- (*system_partition)->mount_point = strdup("/system_recovery_mount");
- }
-
if (!MountPartition(*system_partition)) {
return false;
}
- SwitchRoot((*system_partition)->mount_point);
+ SwitchRoot((*system_partition)->mount_point, true);
mount_fstab_recs_.erase(system_partition);
}
diff --git a/init/init_first_stage.cpp b/init/init_first_stage.cpp
index d81ca5c..4ab1802 100644
--- a/init/init_first_stage.cpp
+++ b/init/init_first_stage.cpp
@@ -14,6 +14,8 @@
* limitations under the License.
*/
+#include <dirent.h>
+#include <fcntl.h>
#include <paths.h>
#include <stdlib.h>
#include <sys/mount.h>
@@ -26,19 +28,72 @@
#include <vector>
#include <android-base/chrono_utils.h>
+#include <android-base/file.h>
#include <android-base/logging.h>
#include <cutils/android_reboot.h>
#include <private/android_filesystem_config.h>
#include "first_stage_mount.h"
#include "reboot_utils.h"
+#include "switch_root.h"
#include "util.h"
using android::base::boot_clock;
+using namespace std::literals;
+
namespace android {
namespace init {
+namespace {
+
+void FreeRamdisk(DIR* dir, dev_t dev) {
+ int dfd = dirfd(dir);
+
+ dirent* de;
+ while ((de = readdir(dir)) != nullptr) {
+ if (de->d_name == "."s || de->d_name == ".."s) {
+ continue;
+ }
+
+ bool is_dir = false;
+
+ if (de->d_type == DT_DIR || de->d_type == DT_UNKNOWN) {
+ struct stat info;
+ if (fstatat(dfd, de->d_name, &info, AT_SYMLINK_NOFOLLOW) != 0) {
+ continue;
+ }
+
+ if (info.st_dev != dev) {
+ continue;
+ }
+
+ if (S_ISDIR(info.st_mode)) {
+ is_dir = true;
+ auto fd = openat(dfd, de->d_name, O_RDONLY | O_DIRECTORY);
+ if (fd >= 0) {
+ auto subdir =
+ std::unique_ptr<DIR, decltype(&closedir)>{fdopendir(fd), closedir};
+ if (subdir) {
+ FreeRamdisk(subdir.get(), dev);
+ } else {
+ close(fd);
+ }
+ }
+ }
+ }
+ unlinkat(dfd, de->d_name, is_dir ? AT_REMOVEDIR : 0);
+ }
+}
+
+bool ForceNormalBoot() {
+ std::string cmdline;
+ android::base::ReadFileToString("/proc/cmdline", &cmdline);
+ return cmdline.find("androidboot.force_normal_boot=1") != std::string::npos;
+}
+
+} // namespace
+
int main(int argc, char** argv) {
if (REBOOT_BOOTLOADER_ON_PANIC) {
InstallRebootSignalHandlers();
@@ -117,10 +172,36 @@
LOG(INFO) << "init first stage started!";
+ auto old_root_dir = std::unique_ptr<DIR, decltype(&closedir)>{opendir("/"), closedir};
+ if (!old_root_dir) {
+ PLOG(ERROR) << "Could not opendir(\"/\"), not freeing ramdisk";
+ }
+
+ struct stat old_root_info;
+ if (stat("/", &old_root_info) != 0) {
+ PLOG(ERROR) << "Could not stat(\"/\"), not freeing ramdisk";
+ old_root_dir.reset();
+ }
+
+ if (ForceNormalBoot()) {
+ mkdir("/first_stage_ramdisk", 0755);
+ SwitchRoot("/first_stage_ramdisk", false);
+ }
+
if (!DoFirstStageMount()) {
LOG(FATAL) << "Failed to mount required partitions early ...";
}
+ struct stat new_root_info;
+ if (stat("/", &new_root_info) != 0) {
+ PLOG(ERROR) << "Could not stat(\"/\"), not freeing ramdisk";
+ old_root_dir.reset();
+ }
+
+ if (old_root_dir && old_root_info.st_dev != new_root_info.st_dev) {
+ FreeRamdisk(old_root_dir.get(), old_root_info.st_dev);
+ }
+
SetInitAvbVersionInRecovery();
static constexpr uint32_t kNanosecondsPerMillisecond = 1e6;
diff --git a/init/switch_root.cpp b/init/switch_root.cpp
index 0e59b57..cc75f31 100644
--- a/init/switch_root.cpp
+++ b/init/switch_root.cpp
@@ -16,7 +16,6 @@
#include "switch_root.h"
-#include <dirent.h>
#include <fcntl.h>
#include <mntent.h>
#include <sys/mount.h>
@@ -35,45 +34,6 @@
namespace {
-void FreeRamdisk(DIR* dir, dev_t dev) {
- int dfd = dirfd(dir);
-
- dirent* de;
- while ((de = readdir(dir)) != nullptr) {
- if (de->d_name == "."s || de->d_name == ".."s) {
- continue;
- }
-
- bool is_dir = false;
-
- if (de->d_type == DT_DIR || de->d_type == DT_UNKNOWN) {
- struct stat info;
- if (fstatat(dfd, de->d_name, &info, AT_SYMLINK_NOFOLLOW) != 0) {
- continue;
- }
-
- if (info.st_dev != dev) {
- continue;
- }
-
- if (S_ISDIR(info.st_mode)) {
- is_dir = true;
- auto fd = openat(dfd, de->d_name, O_RDONLY | O_DIRECTORY);
- if (fd >= 0) {
- auto subdir =
- std::unique_ptr<DIR, decltype(&closedir)>{fdopendir(fd), closedir};
- if (subdir) {
- FreeRamdisk(subdir.get(), dev);
- } else {
- close(fd);
- }
- }
- }
- }
- unlinkat(dfd, de->d_name, is_dir ? AT_REMOVEDIR : 0);
- }
-}
-
std::vector<std::string> GetMounts(const std::string& new_root) {
auto fp = std::unique_ptr<std::FILE, decltype(&endmntent)>{setmntent("/proc/mounts", "re"),
endmntent};
@@ -109,42 +69,32 @@
} // namespace
-void SwitchRoot(const std::string& new_root) {
+void SwitchRoot(const std::string& new_root, bool move_root_mount) {
auto mounts = GetMounts(new_root);
+ LOG(INFO) << "Switching root to '" << new_root << "'";
+
for (const auto& mount_path : mounts) {
auto new_mount_path = new_root + mount_path;
+ mkdir(new_mount_path.c_str(), 0755);
if (mount(mount_path.c_str(), new_mount_path.c_str(), nullptr, MS_MOVE, nullptr) != 0) {
PLOG(FATAL) << "Unable to move mount at '" << mount_path << "'";
}
}
- auto old_root_dir = std::unique_ptr<DIR, decltype(&closedir)>{opendir("/"), closedir};
- if (!old_root_dir) {
- PLOG(ERROR) << "Could not opendir(\"/\"), not freeing ramdisk";
- }
-
- struct stat old_root_info;
- if (stat("/", &old_root_info) != 0) {
- PLOG(ERROR) << "Could not stat(\"/\"), not freeing ramdisk";
- old_root_dir.reset();
- }
-
if (chdir(new_root.c_str()) != 0) {
PLOG(FATAL) << "Could not chdir to new_root, '" << new_root << "'";
}
- if (mount(new_root.c_str(), "/", nullptr, MS_MOVE, nullptr) != 0) {
- PLOG(FATAL) << "Unable to move root mount to new_root, '" << new_root << "'";
+ if (move_root_mount) {
+ if (mount(new_root.c_str(), "/", nullptr, MS_MOVE, nullptr) != 0) {
+ PLOG(FATAL) << "Unable to move root mount to new_root, '" << new_root << "'";
+ }
}
if (chroot(".") != 0) {
PLOG(FATAL) << "Unable to chroot to new root";
}
-
- if (old_root_dir) {
- FreeRamdisk(old_root_dir.get(), old_root_info.st_dev);
- }
}
} // namespace init
diff --git a/init/switch_root.h b/init/switch_root.h
index d515e5d..e12ccee 100644
--- a/init/switch_root.h
+++ b/init/switch_root.h
@@ -21,7 +21,7 @@
namespace android {
namespace init {
-void SwitchRoot(const std::string& new_root);
+void SwitchRoot(const std::string& new_root, bool move_root_mount);
} // namespace init
} // namespace android