Merge "Cleanup for #inclusivefixit." am: b0a9d0e703 (7563eaff) · Commits · e / os / android_system_core

init/mount_namespace.cpp

+13 −46

Original line number	Diff line number	Diff line
		@@ -44,50 +44,17 @@ namespace android {
		namespace init {
		namespace {

		static bool BindMount(const std::string& source, const std::string& mount_point,
		bool recursive = false) {
		unsigned long mountflags = MS_BIND;
		if (recursive) {
		mountflags \|= MS_REC;
		}
		if (mount(source.c_str(), mount_point.c_str(), nullptr, mountflags, nullptr) == -1) {
		static bool BindMount(const std::string& source, const std::string& mount_point) {
		if (mount(source.c_str(), mount_point.c_str(), nullptr, MS_BIND \| MS_REC, nullptr) == -1) {
		PLOG(ERROR) << "Failed to bind mount " << source;
		return false;
		}
		return true;
		}

		static bool MakeShared(const std::string& mount_point, bool recursive = false) {
		unsigned long mountflags = MS_SHARED;
		if (recursive) {
		mountflags \|= MS_REC;
		}
		if (mount(nullptr, mount_point.c_str(), nullptr, mountflags, nullptr) == -1) {
		PLOG(ERROR) << "Failed to change propagation type to shared";
		return false;
		}
		return true;
		}

		static bool MakeSlave(const std::string& mount_point, bool recursive = false) {
		unsigned long mountflags = MS_SLAVE;
		if (recursive) {
		mountflags \|= MS_REC;
		}
		if (mount(nullptr, mount_point.c_str(), nullptr, mountflags, nullptr) == -1) {
		PLOG(ERROR) << "Failed to change propagation type to slave";
		return false;
		}
		return true;
		}

		static bool MakePrivate(const std::string& mount_point, bool recursive = false) {
		unsigned long mountflags = MS_PRIVATE;
		if (recursive) {
		mountflags \|= MS_REC;
		}
		static bool ChangeMount(const std::string& mount_point, unsigned long mountflags) {
		if (mount(nullptr, mount_point.c_str(), nullptr, mountflags, nullptr) == -1) {
		PLOG(ERROR) << "Failed to change propagation type to private";
		PLOG(ERROR) << "Failed to remount " << mount_point << " as " << std::hex << mountflags;
		return false;
		}
		return true;
		@@ -225,17 +192,17 @@ bool SetupMountNamespaces() {
		// needed for /foo/bar, then we will make /foo/bar as a mount point (by
		// bind-mounting by to itself) and set the propagation type of the mount
		// point to private.
		if (!MakeShared("/", true /recursive/)) return false;
		if (!ChangeMount("/", MS_SHARED \| MS_REC)) return false;

		// /apex is a private mountpoint to give different sets of APEXes for
		// the bootstrap and default mount namespaces. The processes running with
		// the bootstrap namespace get APEXes from the read-only partition.
		if (!(MakePrivate("/apex"))) return false;
		if (!(ChangeMount("/apex", MS_PRIVATE))) return false;

		// /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
		// namespace
		if (!(MakePrivate("/linkerconfig"))) return false;
		if (!(ChangeMount("/linkerconfig", MS_PRIVATE))) return false;

		// The two mount namespaces present challenges for scoped storage, because
		// vold, which is responsible for most of the mounting, lives in the
		@@ -266,15 +233,15 @@ bool SetupMountNamespaces() {
		if (!mkdir_recursive("/mnt/user", 0755)) return false;
		if (!mkdir_recursive("/mnt/installer", 0755)) return false;
		if (!mkdir_recursive("/mnt/androidwritable", 0755)) return false;
		if (!(BindMount("/mnt/user", "/mnt/installer", true))) return false;
		if (!(BindMount("/mnt/user", "/mnt/androidwritable", true))) return false;
		if (!(BindMount("/mnt/user", "/mnt/installer"))) return false;
		if (!(BindMount("/mnt/user", "/mnt/androidwritable"))) return false;
		// First, make /mnt/installer and /mnt/androidwritable a slave bind mount
		if (!(MakeSlave("/mnt/installer"))) return false;
		if (!(MakeSlave("/mnt/androidwritable"))) return false;
		if (!(ChangeMount("/mnt/installer", MS_SLAVE))) return false;
		if (!(ChangeMount("/mnt/androidwritable", MS_SLAVE))) return false;
		// Then, make it shared again - effectively creating a new peer group, that
		// will be inherited by new mount namespaces.
		if (!(MakeShared("/mnt/installer"))) return false;
		if (!(MakeShared("/mnt/androidwritable"))) return false;
		if (!(ChangeMount("/mnt/installer", MS_SHARED))) return false;
		if (!(ChangeMount("/mnt/androidwritable", MS_SHARED))) return false;

		bootstrap_ns_fd.reset(OpenMountNamespace());
		bootstrap_ns_id = GetMountNamespaceId();

init/service_utils.cpp

+6 −5

Original line number	Diff line number	Diff line
		@@ -60,13 +60,14 @@ Result<void> EnterNamespace(int nstype, const char* path) {
		Result<void> SetUpMountNamespace(bool remount_proc, bool remount_sys) {
		constexpr unsigned int kSafeFlags = MS_NODEV \| MS_NOEXEC \| MS_NOSUID;

		// Recursively remount / as slave like zygote does so unmounting and mounting /proc
		// doesn't interfere with the parent namespace's /proc mount. This will also
		// prevent any other mounts/unmounts initiated by the service from interfering
		// with the parent namespace but will still allow mount events from the parent
		// Recursively remount / as MS_SLAVE like zygote does so that
		// unmounting and mounting /proc doesn't interfere with the parent
		// namespace's /proc mount. This will also prevent any other
		// mounts/unmounts initiated by the service from interfering with the
		// parent namespace but will still allow mount events from the parent
		// namespace to propagate to the child.
		if (mount("rootfs", "/", nullptr, (MS_SLAVE \| MS_REC), nullptr) == -1) {
		return ErrnoError() << "Could not remount(/) recursively as slave";
		return ErrnoError() << "Could not remount(/) recursively as MS_SLAVE";
		}

		// umount() then mount() /proc and/or /sys