commit e3f9db11135b2ee4a742a2e43ea9da960f1130c9
author Jiyong Park <jiyong@google.com> Sun Dec 08 00:25:15 2019 +0900
committer Jiyong Park <jiyong@google.com> Mon Dec 16 11:31:50 2019 +0900
tree 0a3c4a775eb543319bd50e5dd05066436a811308
parent 88222489021d48cc6a6e211ecd6264beb3e9fa50

Use apex name in apex_manifest.pb as the mount point

When bind-mounting flattened APEX, use the apex name found in
apex_manifest.pb as the mount point, instead of the directory name which
might be different from apex name in case when the apex is overridden.

This allowed us to remove the special casing for the ART apex since we
/system/apex/com.android.art.release will be mounted to
/apex/com.android.art instead of /apex/com.android.art.release.

Bug: N/A
Test: m
Test: OVERRIDE_TARGET_FLATTEN_APEX=true m, device is bootable
Change-Id: Ibdde7002b9078db390e6672b0eb82c474925451d

init/Android.bp

diff --git a/init/Android.bp b/init/Android.bp
index 9529617..42d0b33 100644
--- a/init/Android.bp
+++ b/init/Android.bp
@@ -71,6 +71,7 @@
         "libpropertyinfoserializer",
         "libpropertyinfoparser",
         "libsnapshot_init",
+        "lib_apex_manifest_proto_lite",
     ],
     shared_libs: [
         "libbacktrace",

init/Android.mk

diff --git a/init/Android.mk b/init/Android.mk
index ee2d89a..07b0f95 100644
--- a/init/Android.mk
+++ b/init/Android.mk
@@ -52,7 +52,6 @@
     first_stage_init.cpp \
     first_stage_main.cpp \
     first_stage_mount.cpp \
-    mount_namespace.cpp \
     reboot_utils.cpp \
     selabel.cpp \
     selinux.cpp \

init/mount_namespace.cpp

diff --git a/init/mount_namespace.cpp b/init/mount_namespace.cpp
index c33e0de..648b3bb 100644
--- a/init/mount_namespace.cpp
+++ b/init/mount_namespace.cpp
@@ -27,6 +27,7 @@
 #include <android-base/properties.h>
 #include <android-base/result.h>
 #include <android-base/unique_fd.h>
+#include <apex_manifest.pb.h>
 
 #include "util.h"
 
@@ -90,6 +91,19 @@
     return {};
 }
 
+static Result<std::string> GetApexName(const std::string& apex_dir) {
+    const std::string manifest_path = apex_dir + "/apex_manifest.pb";
+    std::string content;
+    if (!android::base::ReadFileToString(manifest_path, &content)) {
+        return Error() << "Failed to read manifest file: " << manifest_path;
+    }
+    apex::proto::ApexManifest manifest;
+    if (!manifest.ParseFromString(content)) {
+        return Error() << "Can't parse manifest file: " << manifest_path;
+    }
+    return manifest.name();
+}
+
 static Result<void> ActivateFlattenedApexesFrom(const std::string& from_dir,
                                                 const std::string& to_dir) {
     std::unique_ptr<DIR, decltype(&closedir)> dir(opendir(from_dir.c_str()), closedir);
@@ -101,7 +115,12 @@
         if (entry->d_name[0] == '.') continue;
         if (entry->d_type == DT_DIR) {
             const std::string apex_path = from_dir + "/" + entry->d_name;
-            const std::string mount_path = to_dir + "/" + entry->d_name;
+            const auto apex_name = GetApexName(apex_path);
+            if (!apex_name) {
+                LOG(ERROR) << apex_path << " is not an APEX directory: " << apex_name.error();
+                continue;
+            }
+            const std::string mount_path = to_dir + "/" + (*apex_name);
             if (auto result = MountDir(apex_path, mount_path); !result) {
                 return result;
             }
@@ -129,26 +148,7 @@
             return false;
         }
     }
-    // Special casing for the ART APEX
-    constexpr const char kArtApexMountPath[] = "/apex/com.android.art";
-    static const std::vector<std::string> kArtApexDirNames = {"com.android.art.release",
-                                                              "com.android.art.debug"};
-    bool success = false;
-    for (const auto& name : kArtApexDirNames) {
-        std::string path = kApexTop + "/" + name;
-        if (access(path.c_str(), F_OK) == 0) {
-            if (auto result = MountDir(path, kArtApexMountPath); !result) {
-                LOG(ERROR) << result.error();
-                return false;
-            }
-            success = true;
-            break;
-        }
-    }
-    if (!success) {
-        PLOG(ERROR) << "Failed to bind mount the ART APEX to " << kArtApexMountPath;
-    }
-    return success;
+    return true;
 }
 
 static android::base::unique_fd bootstrap_ns_fd;