Merge "Generate linkerconfig per mount namespaces" (80416f7a) · Commits · e / os / android_system_core

init/builtins.cpp

+44 −0

Original line number	Diff line number	Diff line
		@@ -59,6 +59,7 @@
		#include <fs_mgr.h>
		#include <fscrypt/fscrypt.h>
		#include <libgsi/libgsi.h>
		#include <logwrap/logwrap.h>
		#include <selinux/android.h>
		#include <selinux/label.h>
		#include <selinux/selinux.h>
		@@ -1176,6 +1177,42 @@ static Result<void> do_mark_post_data(const BuiltinArguments& args) {
		return {};
		}

		static Result<void> GenerateLinkerConfiguration() {
		const char* linkerconfig_binary = "/system/bin/linkerconfig";
		const char* linkerconfig_target = "/linkerconfig/ld.config.txt";
		const char* arguments[] = {linkerconfig_binary, "--target", linkerconfig_target};

		if (logwrap_fork_execvp(arraysize(arguments), arguments, nullptr, false, LOG_KLOG, false,
		nullptr) != 0) {
		return ErrnoError() << "failed to execute linkerconfig";
		}

		mode_t mode = get_mode("0444");
		if (fchmodat(AT_FDCWD, linkerconfig_target, mode, AT_SYMLINK_NOFOLLOW) < 0) {
		return ErrnoErrorIgnoreEnoent() << "fchmodat() failed";
		}

		LOG(INFO) << "linkerconfig generated " << linkerconfig_target
		<< " with mounted APEX modules info";

		return {};
		}

		static bool IsApexUpdatable() {
		static bool updatable = android::sysprop::ApexProperties::updatable().value_or(false);
		return updatable;
		}

		static Result<void> do_update_linker_config(const BuiltinArguments&) {
		// If APEX is not updatable, then all APEX information are already included in the first
		// linker config generation, so there is no need to update linker configuration again.
		if (IsApexUpdatable()) {
		return GenerateLinkerConfiguration();
		}

		return {};
		}

		static Result<void> parse_apex_configs() {
		glob_t glob_result;
		static constexpr char glob_pattern[] = "/apex//etc/.rc";
		@@ -1251,6 +1288,12 @@ static Result<void> do_perform_apex_config(const BuiltinArguments& args) {
		if (!parse_configs) {
		return parse_configs.error();
		}

		auto update_linker_config = do_update_linker_config(args);
		if (!update_linker_config) {
		return update_linker_config.error();
		}

		return {};
		}

		@@ -1317,6 +1360,7 @@ const BuiltinFunctionMap& GetBuiltinFunctionMap() {
		{"perform_apex_config", {0, 0, {false, do_perform_apex_config}}},
		{"umount", {1, 1, {false, do_umount}}},
		{"umount_all", {1, 1, {false, do_umount_all}}},
		{"update_linker_config", {0, 0, {false, do_update_linker_config}}},
		{"readahead", {1, 2, {true, do_readahead}}},
		{"remount_userdata", {0, 0, {false, do_remount_userdata}}},
		{"restart", {1, 1, {false, do_restart}}},

init/mount_namespace.cpp

+19 −0

Original line number	Diff line number	Diff line
		@@ -151,6 +151,20 @@ static bool ActivateFlattenedApexesIfPossible() {
		return true;
		}

		static Result<void> MountLinkerConfigForDefaultNamespace() {
		// No need to mount linkerconfig for default mount namespace if the path does not exist (which
		// would mean it is already mounted)
		if (access("/linkerconfig/default", 0) != 0) {
		return {};
		}

		if (mount("/linkerconfig/default", "/linkerconfig", nullptr, MS_BIND \| MS_REC, nullptr) != 0) {
		return ErrnoError() << "Failed to mount linker configuration for default mount namespace.";
		}

		return {};
		}

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

		@@ -222,6 +236,11 @@ bool SwitchToDefaultMountNamespace() {
		PLOG(ERROR) << "Failed to switch back to the default mount namespace.";
		return false;
		}

		if (auto result = MountLinkerConfigForDefaultNamespace(); !result) {
		LOG(ERROR) << result.error();
		return false;
		}
		}

		LOG(INFO) << "Switched to default mount namespace";

rootdir/init.rc

+14 −2

Original line number	Diff line number	Diff line
		@@ -38,9 +38,18 @@ on early-init
		# Allow up to 32K FDs per process
		setrlimit nofile 32768 32768

		# Set up linker config subdirectories based on mount namespaces
		mkdir /linkerconfig/bootstrap 0755
		mkdir /linkerconfig/default 0755

		# Generate ld.config.txt for early executed processes
		exec -- /system/bin/linkerconfig --target /linkerconfig/ld.config.txt
		chmod 444 /linkerconfig/ld.config.txt
		exec -- /system/bin/linkerconfig --target /linkerconfig/bootstrap/ld.config.txt
		chmod 644 /linkerconfig/bootstrap/ld.config.txt
		copy /linkerconfig/bootstrap/ld.config.txt /linkerconfig/default/ld.config.txt
		chmod 644 /linkerconfig/default/ld.config.txt

		# Mount bootstrap linker configuration as current
		mount none /linkerconfig/bootstrap /linkerconfig bind rec

		start ueventd

		@@ -49,6 +58,9 @@ on early-init
		# the libraries are available to the processes started after this statement.
		exec_start apexd-bootstrap

		# Generate linker config based on apex mounted in bootstrap namespace
		update_linker_config

		# These must already exist by the time boringssl_self_test32 / boringssl_self_test64 run.
		mkdir /dev/boringssl 0755 root root
		mkdir /dev/boringssl/selftest 0755 root root