Merge "Revert "Use /bootstrap-apex for bootstrap APEXes"" into main am:... (25020cba) · Commits · e / os / android_system_core

init/builtins.cpp

+0 −50

Original line number	Original line	Diff line number	Diff line
	@@ -1262,51 +1262,6 @@ static Result<void> MountLinkerConfigForDefaultNamespace() {

	return {};		return {};
	}		}

	static Result<void> MountApexRootForDefaultNamespace() {
	auto mount_namespace_id = GetCurrentMountNamespace();
	if (!mount_namespace_id.ok()) {
	return mount_namespace_id.error();
	}
	// There's nothing to do if it's still in the bootstrap mount namespace.
	// This happens when we don't need to update APEXes (e.g. Microdroid)
	// where bootstrap mount namespace == default mount namespace.
	if (mount_namespace_id.value() == NS_BOOTSTRAP) {
	return {};
	}

	// Now, we're in the "default" mount namespace and need a fresh /apex for
	// the default mount namespace.
	//
	// At this point, there are two mounts at the same mount point: /apex
	// - to tmpfs (private)
	// - to /bootstrap-apex (shared)
	//
	// We need unmount the second mount so that /apex in the default mount
	// namespace becomes RW/empty and "private" (we don't want mount events to
	// propagate to the bootstrap mount namespace).
	//
	// Likewise, we don't want the unmount event itself to propagate to the
	// bootstrap mount namespace. Otherwise, /apex in the bootstrap mount
	// namespace would become empty due to the unmount.
	//
	// Hence, before unmounting, we make /apex (the second one) "private" first.
	// so that the unmouting below doesn't affect to the bootstrap mount namespace.
	if (mount(nullptr, "/apex", nullptr, MS_PRIVATE \| MS_REC, nullptr) == -1) {
	return ErrnoError() << "Failed to remount /apex as private";
	}

	// Now we can unmount /apex (bind-mount to /bootstrap-apex). This only affects
	// in the default mount namespace and /apex is now seen as tmpfs mount.
	// Note that /apex in the bootstrap mount namespace is still a bind-mount to
	// /bootstrap-apex and holds the APEX mounts.
	if (umount2("/apex", MNT_DETACH) == -1) {
	return ErrnoError() << "Failed to umount /apex";
	}

	return {};
	}

	static Result<void> do_update_linker_config(const BuiltinArguments&) {		static Result<void> do_update_linker_config(const BuiltinArguments&) {
	return GenerateLinkerConfiguration();		return GenerateLinkerConfiguration();
	}		}
	@@ -1360,11 +1315,6 @@ static Result<void> do_enter_default_mount_ns(const BuiltinArguments& args) {
	if (auto result = SwitchToMountNamespaceIfNeeded(NS_DEFAULT); !result.ok()) {		if (auto result = SwitchToMountNamespaceIfNeeded(NS_DEFAULT); !result.ok()) {
	return result.error();		return result.error();
	}		}

	if (auto result = MountApexRootForDefaultNamespace(); !result.ok()) {
	return result.error();
	}

	if (auto result = MountLinkerConfigForDefaultNamespace(); !result.ok()) {		if (auto result = MountLinkerConfigForDefaultNamespace(); !result.ok()) {
	return result.error();		return result.error();
	}		}

init/init.cpp

+0 −6

Original line number	Original line	Diff line number	Diff line
	@@ -832,12 +832,6 @@ static void MountExtraFilesystems() {
	CHECKCALL(mount("tmpfs", "/apex", "tmpfs", MS_NOEXEC \| MS_NOSUID \| MS_NODEV,		CHECKCALL(mount("tmpfs", "/apex", "tmpfs", MS_NOEXEC \| MS_NOSUID \| MS_NODEV,
	"mode=0755,uid=0,gid=0"));		"mode=0755,uid=0,gid=0"));

	if (NeedsTwoMountNamespaces()) {
	// /bootstrap-apex is used to mount "bootstrap" APEXes.
	CHECKCALL(mount("tmpfs", "/bootstrap-apex", "tmpfs", MS_NOEXEC \| MS_NOSUID \| MS_NODEV,
	"mode=0755,uid=0,gid=0"));
	}

	// /linkerconfig is used to keep generated linker configuration		// /linkerconfig is used to keep generated linker configuration
	CHECKCALL(mount("tmpfs", "/linkerconfig", "tmpfs", MS_NOEXEC \| MS_NOSUID \| MS_NODEV,		CHECKCALL(mount("tmpfs", "/linkerconfig", "tmpfs", MS_NOEXEC \| MS_NOSUID \| MS_NODEV,
	"mode=0755,uid=0,gid=0"));		"mode=0755,uid=0,gid=0"));

init/mount_namespace.cpp

+9 −30

Original line number	Original line	Diff line number	Diff line
	@@ -66,23 +66,23 @@ static std::string GetMountNamespaceId() {
	return ret;		return ret;
	}		}

	static android::base::unique_fd bootstrap_ns_fd;
	static android::base::unique_fd default_ns_fd;

	static std::string bootstrap_ns_id;
	static std::string default_ns_id;

	} // namespace

	// In case we have two sets of APEXes (non-updatable, updatable), we need two separate mount		// In case we have two sets of APEXes (non-updatable, updatable), we need two separate mount
	// namespaces.		// namespaces.
	bool NeedsTwoMountNamespaces() {		static bool NeedsTwoMountNamespaces() {
	if (IsRecoveryMode()) return false;		if (IsRecoveryMode()) return false;
	// In microdroid, there's only one set of APEXes in built-in directories include block devices.		// In microdroid, there's only one set of APEXes in built-in directories include block devices.
	if (IsMicrodroid()) return false;		if (IsMicrodroid()) return false;
	return true;		return true;
	}		}

			static android::base::unique_fd bootstrap_ns_fd;
			static android::base::unique_fd default_ns_fd;

			static std::string bootstrap_ns_id;
			static std::string default_ns_id;

			} // namespace

	bool SetupMountNamespaces() {		bool SetupMountNamespaces() {
	// Set the propagation type of / as shared so that any mounting event (e.g.		// Set the propagation type of / as shared so that any mounting event (e.g.
	// /data) is by default visible to all processes. When private mounting is		// /data) is by default visible to all processes. When private mounting is
	@@ -96,27 +96,6 @@ bool SetupMountNamespaces() {
	// the bootstrap namespace get APEXes from the read-only partition.		// the bootstrap namespace get APEXes from the read-only partition.
	if (!(ChangeMount("/apex", MS_PRIVATE))) return false;		if (!(ChangeMount("/apex", MS_PRIVATE))) return false;

	// However, some components (e.g. servicemanager) need to access bootstrap
	// APEXes from the default mount namespace. To achieve that, we bind-mount
	// /apex with /bootstrap-apex (not private) in the bootstrap mount namespace.
	// Bootstrap APEXes are mounted in /apex and also visible in /bootstrap-apex.
	// In the default mount namespace, we detach /bootstrap-apex from /apex and
	// bootstrap APEXes are still be visible in /bootstrap-apex.
	//
	// The end result will look like:
	// in the bootstrap mount namespace:
	// /apex (== /bootstrap-apex)
	// {bootstrap APEXes from the read-only partition}
	//
	// in the default mount namespace:
	// /bootstrap-apex
	// {bootstrap APEXes from the read-only partition}
	// /apex
	// {APEXes, can be from /data partition}
	if (NeedsTwoMountNamespaces()) {
	if (!(BindMount("/bootstrap-apex", "/apex"))) return false;
	}

	// /linkerconfig is a private mountpoint to give a different linker configuration		// /linkerconfig is a private mountpoint to give a different linker configuration
	// based on the mount namespace. Subdirectory will be bind-mounted based on current mount		// based on the mount namespace. Subdirectory will be bind-mounted based on current mount
	// namespace		// namespace

init/mount_namespace.h

+0 −3

Original line number	Original line	Diff line number	Diff line
	@@ -24,12 +24,9 @@ namespace init {
	enum MountNamespace { NS_BOOTSTRAP, NS_DEFAULT };		enum MountNamespace { NS_BOOTSTRAP, NS_DEFAULT };

	bool SetupMountNamespaces();		bool SetupMountNamespaces();

	base::Result<void> SwitchToMountNamespaceIfNeeded(MountNamespace target_mount_namespace);		base::Result<void> SwitchToMountNamespaceIfNeeded(MountNamespace target_mount_namespace);

	base::Result<MountNamespace> GetCurrentMountNamespace();		base::Result<MountNamespace> GetCurrentMountNamespace();

	bool NeedsTwoMountNamespaces();

	} // namespace init		} // namespace init
	} // namespace android		} // namespace android

init/selinux.cpp

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -766,7 +766,7 @@ void SelinuxRestoreContext() {
	selinux_android_restorecon("/dev/device-mapper", 0);		selinux_android_restorecon("/dev/device-mapper", 0);

	selinux_android_restorecon("/apex", 0);		selinux_android_restorecon("/apex", 0);
	selinux_android_restorecon("/bootstrap-apex", 0);
	selinux_android_restorecon("/linkerconfig", 0);		selinux_android_restorecon("/linkerconfig", 0);

	// adb remount, snapshot-based updates, and DSUs all create files during		// adb remount, snapshot-based updates, and DSUs all create files during