Merge changes from topic "apex_earlymount_base"

* changes:
  Activate system APEXes early
  mount /apex during first_stage init

init/builtins.cpp

@@ -1119,13 +1119,21 @@ static Result<Success> do_parse_apex_configs(const BuiltinArguments& args) {
 }
 
 static Result<Success> do_setup_runtime_bionic(const BuiltinArguments& args) {
-    if (SwitchToDefaultMountNamespace()) {
+    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();
+    } else {
+        return Error() << "Failed to enter into default mount namespace";
+    }
+}
+
 // Builtin-function-map start
 const BuiltinFunctionMap::Map& BuiltinFunctionMap::map() const {
     constexpr std::size_t kMax = std::numeric_limits<std::size_t>::max();
@@ -1177,6 +1185,7 @@ const BuiltinFunctionMap::Map& BuiltinFunctionMap::map() const {
         {"start",                   {1,     1,    {false,  do_start}}},
         {"stop",                    {1,     1,    {false,  do_stop}}},
         {"swapon_all",              {1,     1,    {false,  do_swapon_all}}},
+        {"enter_default_mount_ns",  {0,     0,    {false,  do_enter_default_mount_ns}}},
         {"symlink",                 {2,     2,    {true,   do_symlink}}},
         {"sysclktz",                {1,     1,    {false,  do_sysclktz}}},
         {"trigger",                 {1,     1,    {false,  do_trigger}}},

init/first_stage_init.cpp

@@ -155,6 +155,10 @@ int FirstStageMain(int argc, char** argv) {
     // part of the product partition, e.g. because they are mounted read-write.
     CHECKCALL(mkdir("/mnt/product", 0755));
 
+    // /apex is used to mount APEXes
+    CHECKCALL(mount("tmpfs", "/apex", "tmpfs", MS_NOEXEC | MS_NOSUID | MS_NODEV,
+                    "mode=0755,uid=0,gid=0"));
+
 #undef CHECKCALL
 
     // Now that tmpfs is mounted on /dev and we have /dev/kmsg, we can actually

init/mount_namespace.cpp

@@ -172,6 +172,11 @@ bool SetupMountNamespaces() {
                          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;
+
     bootstrap_ns_fd.reset(OpenMountNamespace());
     bootstrap_ns_id = GetMountNamespaceId();
 
@@ -227,6 +232,17 @@ bool SwitchToDefaultMountNamespace() {
         }
     }
 
+    LOG(INFO) << "Switched to default mount namespace";
+    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 IsBionicUpdatable() == false, these mounts are over the
     // existing existing bind mounts for the bootstrap bionic, which effectively
@@ -238,7 +254,7 @@ bool SwitchToDefaultMountNamespace() {
                          kBionicLibsMountPointDir64))
         return false;
 
-    LOG(INFO) << "Switched to default mount namespace";
+    LOG(INFO) << "Runtime bionic is set up";
     return true;
 }
 

init/mount_namespace.h

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

init/selinux.cpp

@@ -459,6 +459,8 @@ void SelinuxRestoreContext() {
 
     selinux_android_restorecon("/dev/block", SELINUX_ANDROID_RESTORECON_RECURSE);
     selinux_android_restorecon("/dev/device-mapper", 0);
+
+    selinux_android_restorecon("/apex", 0);
 }
 
 int SelinuxKlogCallback(int type, const char* fmt, ...) {

rootdir/init.rc

@@ -13,12 +13,6 @@ import /init.${ro.zygote}.rc
 
 # Cgroups are mounted right before early-init using list from /etc/cgroups.json
 on early-init
-    # Mount shared so changes propagate into child namespaces
-    # Do this before other processes are started from init. Otherwise,
-    # processes launched while the propagation type of / is 'private'
-    # won't get mount events from others.
-    mount rootfs rootfs / shared rec
-
     # Set init and its forked children's oom_adj.
     write /proc/1/oom_score_adj -1000
 
@@ -43,6 +37,11 @@ on early-init
 
     start ueventd
 
+    # Run apexd-bootstrap so that APEXes that provide critical libraries
+    # become available. Note that this is executed as exec_start to ensure that
+    # the libraries are available to the processes started after this statement.
+    exec_start apexd-bootstrap
+
 on init
     sysclktz 0
 
@@ -278,18 +277,9 @@ on init
     write /dev/cpu_variant:${ro.bionic.2nd_arch} ${ro.bionic.2nd_cpu_variant}
     chmod 0444 /dev/cpu_variant:${ro.bionic.2nd_arch}
 
-    # Setup APEX mount point and its security context
-    mount tmpfs tmpfs /apex nodev noexec nosuid
-    chmod 0755 /apex
-    chown root root /apex
-    restorecon /apex
-
     # Start logd before any other services run to ensure we capture all of their logs.
     start logd
 
-    # Start apexd as soon as we can
-    start apexd
-
     # Start essential services.
     start servicemanager
     start hwservicemanager
@@ -425,8 +415,16 @@ on post-fs-data
     mkdir /data/bootchart 0755 shell shell
     bootchart start
 
-    # /data/apex is now available. Let apexd to scan and activate APEXes.
-    setprop apexd.data.status ready
+    # Make sure that apexd is started in the default namespace
+    enter_default_mount_ns
+
+    # /data/apex is now available. Start apexd to scan and activate APEXes.
+    mkdir /data/apex 0750 root system
+    mkdir /data/apex/active 0750 root system
+    mkdir /data/apex/backup 0700 root system
+    mkdir /data/apex/sessions 0700 root system
+    mkdir /data/pkg_staging 0750 system system
+    start apexd
 
     # Avoid predictable entropy pool. Carry over entropy from previous boot.
     copy /data/system/entropy.dat /dev/urandom
@@ -543,12 +541,6 @@ on post-fs-data
 
     mkdir /data/anr 0775 system system
 
-    mkdir /data/apex 0750 root system
-    mkdir /data/apex/active 0750 root system
-    mkdir /data/apex/backup 0700 root system
-    mkdir /data/apex/sessions 0700 root system
-    mkdir /data/pkg_staging 0750 system system
-
     # NFC: create data/nfc for nv storage
     mkdir /data/nfc 0770 nfc nfc
     mkdir /data/nfc/param 0770 nfc nfc
@@ -581,6 +573,12 @@ on post-fs-data
     mkdir /data/cache/backup_stage 0700 system system
     mkdir /data/cache/backup 0700 system system
 
+    # 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
 
     # Set SELinux security contexts on upgrade or policy update.
@@ -589,14 +587,6 @@ on post-fs-data
     # load fsverity keys
     exec -- /system/bin/mini-keyctl -c /product/etc/security/cacerts_fsverity,/vendor/etc/security/cacerts_fsverity -k .fs-verity
 
-    # Wait for apexd to finish activating APEXes before starting more processes.
-    # This certainly reduces the parallelism but is required to make as many processes
-    # as possible to use the bionic libs from the runtime APEX. This takes less than 50ms
-    # so the impact on the booting time is not significant.
-    wait_for_prop apexd.status ready
-    setup_runtime_bionic
-    parse_apex_configs
-
     # Check any timezone data in /data is newer than the copy in the runtime module, delete if not.
     exec - system system -- /system/bin/tzdatacheck /apex/com.android.runtime/etc/tz /data/misc/zoneinfo