Don't bind-mount bionic files

am: 7b4801a921

Change-Id: I80ded3b5efbee209eb705556bc92e2708497da20

init/builtins.cpp

@@ -1118,14 +1118,6 @@ static Result<Success> do_parse_apex_configs(const BuiltinArguments& args) {
     }
 }
 
-static Result<Success> do_setup_runtime_bionic(const BuiltinArguments& args) {
-    if (SetupRuntimeBionic()) {
-        return Success();
-    } else {
-        return Error() << "Failed to setup runtime bionic";
-    }
-}
-
 static Result<Success> do_enter_default_mount_ns(const BuiltinArguments& args) {
     if (SwitchToDefaultMountNamespace()) {
         return Success();
@@ -1181,7 +1173,6 @@ const BuiltinFunctionMap::Map& BuiltinFunctionMap::map() const {
         {"rmdir",                   {1,     1,    {true,   do_rmdir}}},
         {"setprop",                 {2,     2,    {true,   do_setprop}}},
         {"setrlimit",               {3,     3,    {false,  do_setrlimit}}},
-        {"setup_runtime_bionic",    {0,     0,    {false,  do_setup_runtime_bionic}}},
         {"start",                   {1,     1,    {false,  do_start}}},
         {"stop",                    {1,     1,    {false,  do_stop}}},
         {"swapon_all",              {1,     1,    {false,  do_swapon_all}}},

init/mount_namespace.cpp

@@ -33,37 +33,6 @@ namespace android {
 namespace init {
 namespace {
 
-static constexpr const char* kLinkerMountPoint = "/bionic/bin/linker";
-static constexpr const char* kBootstrapLinkerPath = "/system/bin/bootstrap/linker";
-static constexpr const char* kRuntimeLinkerPath = "/apex/com.android.runtime/bin/linker";
-
-static constexpr const char* kBionicLibsMountPointDir = "/bionic/lib/";
-static constexpr const char* kBootstrapBionicLibsDir = "/system/lib/bootstrap/";
-static constexpr const char* kRuntimeBionicLibsDir = "/apex/com.android.runtime/lib/bionic/";
-
-static constexpr const char* kLinkerMountPoint64 = "/bionic/bin/linker64";
-static constexpr const char* kBootstrapLinkerPath64 = "/system/bin/bootstrap/linker64";
-static constexpr const char* kRuntimeLinkerPath64 = "/apex/com.android.runtime/bin/linker64";
-
-static constexpr const char* kBionicLibsMountPointDir64 = "/bionic/lib64/";
-static constexpr const char* kBootstrapBionicLibsDir64 = "/system/lib64/bootstrap/";
-static constexpr const char* kRuntimeBionicLibsDir64 = "/apex/com.android.runtime/lib64/bionic/";
-
-static const std::vector<std::string> kBionicLibFileNames = {"libc.so", "libm.so", "libdl.so"};
-
-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) {
-        PLOG(ERROR) << "Could not bind-mount " << source << " to " << mount_point;
-        return false;
-    }
-    return true;
-}
-
 static bool MakeShared(const std::string& mount_point, bool recursive = false) {
     unsigned long mountflags = MS_SHARED;
     if (recursive) {
@@ -105,34 +74,6 @@ static std::string GetMountNamespaceId() {
     return ret;
 }
 
-static bool BindMountBionic(const std::string& linker_source, const std::string& lib_dir_source,
-                            const std::string& linker_mount_point,
-                            const std::string& lib_mount_dir) {
-    if (access(linker_source.c_str(), F_OK) != 0) {
-        PLOG(INFO) << linker_source << " does not exist. skipping mounting bionic there.";
-        // This can happen for 64-bit bionic in 32-bit only device.
-        // It is okay to skip mounting the 64-bit bionic.
-        return true;
-    }
-    if (!BindMount(linker_source, linker_mount_point)) {
-        return false;
-    }
-    if (!MakePrivate(linker_mount_point)) {
-        return false;
-    }
-    for (const auto& libname : kBionicLibFileNames) {
-        std::string mount_point = lib_mount_dir + libname;
-        std::string source = lib_dir_source + libname;
-        if (!BindMount(source, mount_point)) {
-            return false;
-        }
-        if (!MakePrivate(mount_point)) {
-            return false;
-        }
-    }
-    return true;
-}
-
 static bool IsApexUpdatable() {
     static bool updatable = android::sysprop::ApexProperties::updatable().value_or(false);
     return updatable;
@@ -154,26 +95,7 @@ bool SetupMountNamespaces() {
     // point to private.
     if (!MakeShared("/", true /*recursive*/)) return false;
 
-    // Since different files (bootstrap or runtime APEX) should be mounted to
+    // /apex is a private mountpoint to give different sets of APEXes for
-    // the same mount point paths (e.g. /bionic/bin/linker, /bionic/lib/libc.so,
-    // etc.) across the two mount namespaces, we create a private mount point at
-    // /bionic so that a mount event for the bootstrap bionic in the mount
-    // namespace for pre-apexd processes is not propagated to the other mount
-    // namespace for post-apexd process, and vice versa.
-    //
-    // Other mount points other than /bionic, however, are all still shared.
-    if (!BindMount("/bionic", "/bionic", true /*recursive*/)) return false;
-    if (!MakePrivate("/bionic")) return false;
-
-    // Bind-mount bootstrap bionic.
-    if (!BindMountBionic(kBootstrapLinkerPath, kBootstrapBionicLibsDir, kLinkerMountPoint,
-                         kBionicLibsMountPointDir))
-        return false;
-    if (!BindMountBionic(kBootstrapLinkerPath64, kBootstrapBionicLibsDir64, kLinkerMountPoint64,
-                         kBionicLibsMountPointDir64))
-        return false;
-
-    // /apex is also 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;
@@ -181,12 +103,11 @@ bool SetupMountNamespaces() {
     bootstrap_ns_fd.reset(OpenMountNamespace());
     bootstrap_ns_id = GetMountNamespaceId();
 
-    // When bionic is updatable via the runtime APEX, we create separate mount
+    // When APEXes are updatable (e.g. not-flattened), we create separate mount
     // namespaces for processes that are started before and after the APEX is
-    // activated by apexd. In the namespace for pre-apexd processes, the bionic
+    // activated by apexd. In the namespace for pre-apexd processes, small
-    // from the /system partition (that we call bootstrap bionic) is
+    // number of essential APEXes (e.g. com.android.runtime) are activated.
-    // bind-mounted. In the namespace for post-apexd processes, the bionic from
+    // In the namespace for post-apexd processes, all APEXes are activated.
-    // the runtime APEX is bind-mounted.
     bool success = true;
     if (IsApexUpdatable() && !IsRecoveryMode()) {
         // Creating a new namespace by cloning, saving, and switching back to
@@ -198,15 +119,6 @@ bool SetupMountNamespaces() {
         default_ns_fd.reset(OpenMountNamespace());
         default_ns_id = GetMountNamespaceId();
 
-        // By this unmount, the bootstrap bionic are not mounted in the default
-        // mount namespace.
-        if (umount2("/bionic", MNT_DETACH) == -1) {
-            PLOG(ERROR) << "Cannot unmount /bionic";
-            // Don't return here. We have to switch back to the bootstrap
-            // namespace.
-            success = false;
-        }
-
         if (setns(bootstrap_ns_fd.get(), CLONE_NEWNS) == -1) {
             PLOG(ERROR) << "Cannot switch back to bootstrap mount namespace";
             return false;
@@ -237,28 +149,6 @@ bool SwitchToDefaultMountNamespace() {
     return true;
 }
 
-// TODO(jiyong): remove this when /system/lib/libc.so becomes
-// a symlink to /apex/com.android.runtime/lib/bionic/libc.so
-bool SetupRuntimeBionic() {
-    if (IsRecoveryMode()) {
-        // We don't have multiple namespaces in recovery mode
-        return true;
-    }
-    // Bind-mount bionic from the runtime APEX since it is now available. Note
-    // that in case of IsApexUpdatable() == false, these mounts are over the
-    // existing existing bind mounts for the bootstrap bionic, which effectively
-    // becomes hidden.
-    if (!BindMountBionic(kRuntimeLinkerPath, kRuntimeBionicLibsDir, kLinkerMountPoint,
-                         kBionicLibsMountPointDir))
-        return false;
-    if (!BindMountBionic(kRuntimeLinkerPath64, kRuntimeBionicLibsDir64, kLinkerMountPoint64,
-                         kBionicLibsMountPointDir64))
-        return false;
-
-    LOG(INFO) << "Runtime bionic is set up";
-    return true;
-}
-
 bool SwitchToBootstrapMountNamespaceIfNeeded() {
     if (IsRecoveryMode()) {
         // we don't have multiple namespaces in recovery mode

init/mount_namespace.h

@@ -20,7 +20,6 @@ namespace android {
 namespace init {
 
 bool SetupMountNamespaces();
-bool SetupRuntimeBionic();
 bool SwitchToDefaultMountNamespace();
 bool SwitchToBootstrapMountNamespaceIfNeeded();
 

rootdir/etc/ld.config.txt

@@ -83,7 +83,7 @@ namespace.default.permitted.paths += /%PRODUCT_SERVICES%/app
 namespace.default.permitted.paths += /%PRODUCT_SERVICES%/priv-app
 namespace.default.permitted.paths += /data
 namespace.default.permitted.paths += /mnt/expand
-namespace.default.permitted.paths += /bionic/${LIB}
+namespace.default.permitted.paths += /apex/com.android.runtime/${LIB}/bionic
 namespace.default.permitted.paths += /system/${LIB}/bootstrap
 
 namespace.default.asan.search.paths  = /data/asan/system/${LIB}
@@ -119,7 +119,7 @@ namespace.default.asan.permitted.paths += /%PRODUCT_SERVICES%/framework
 namespace.default.asan.permitted.paths += /%PRODUCT_SERVICES%/app
 namespace.default.asan.permitted.paths += /%PRODUCT_SERVICES%/priv-app
 namespace.default.asan.permitted.paths += /mnt/expand
-namespace.default.asan.permitted.paths += /bionic/${LIB}
+namespace.default.asan.permitted.paths += /apex/com.android.runtime/${LIB}/bionic
 namespace.default.asan.permitted.paths += /system/${LIB}/bootstrap
 
 # Keep in sync with ld.config.txt in the com.android.runtime APEX.

rootdir/init.rc

@@ -578,8 +578,6 @@ on post-fs-data
 
     # Wait for apexd to finish activating APEXes before starting more processes.
     wait_for_prop apexd.status ready
-    # TODO(jiyong): remove setup_runtime_bionic
-    setup_runtime_bionic
     parse_apex_configs
 
     init_user0