From 6d0792551024693ae2779a4d9e6380f9b969d4fe Mon Sep 17 00:00:00 2001
From: Jooyung Han <jooyung@google.com>
Date: Fri, 11 Aug 2023 15:34:35 +0000
Subject: [PATCH 1/2] Revert "Use apexservice to get the list of apexes"

Revert submission 2685449-apexdata-dirs

Reason for revert: b/295345486 performance regression.

Reverted changes: /q/submissionid:2685449-apexdata-dirs

Bug: b/295345486
Test: n/a
Change-Id: I710a416398148b544635e32e6b8066fb0560171f
---
 Android.bp               |  5 +----
 vold_prepare_subdirs.cpp | 41 +++++++++++++---------------------------
 2 files changed, 14 insertions(+), 32 deletions(-)

diff --git a/Android.bp b/Android.bp
index 1240efc..7e41f22 100644
--- a/Android.bp
+++ b/Android.bp
@@ -239,10 +239,7 @@ cc_binary {
 
 cc_binary {
     name: "vold_prepare_subdirs",
-    defaults: [
-        "vold_default_flags",
-        "libapexservice-deps",
-    ],
+    defaults: ["vold_default_flags"],
 
     srcs: [
         "vold_prepare_subdirs.cpp",
diff --git a/vold_prepare_subdirs.cpp b/vold_prepare_subdirs.cpp
index e41e994..60e82f5 100644
--- a/vold_prepare_subdirs.cpp
+++ b/vold_prepare_subdirs.cpp
@@ -30,11 +30,7 @@
 #include <sys/types.h>
 
 #include <android-base/logging.h>
-#include <android-base/result.h>
 #include <android-base/scopeguard.h>
-#include <android/apex/ApexInfo.h>
-#include <android/apex/IApexService.h>
-#include <binder/IServiceManager.h>
 
 #include <cutils/fs.h>
 #include <selinux/android.h>
@@ -145,35 +141,24 @@ static bool rmrf_contents(const std::string& path) {
     }
 }
 
-static android::base::Result<std::vector<std::string>> get_apex_list() {
-    auto sm = android::defaultServiceManager();
-    auto binder = sm->waitForService(android::String16("apexservice"));
-    if (binder == nullptr) {
-        return android::base::Error() << "Failed to get apexservice";
-    }
-    auto service = android::interface_cast<android::apex::IApexService>(binder);
-    std::vector<android::apex::ApexInfo> list;
-    auto status = service->getActivePackages(&list);
-    if (!status.isOk()) {
-        return android::base::Error() << status.exceptionMessage().c_str();
-    }
-    std::vector<std::string> names;
-    names.reserve(list.size());
-    for (const auto& apex_info : list) {
-        names.push_back(apex_info.moduleName);
-    }
-    return names;
-}
-
 static bool prepare_apex_subdirs(struct selabel_handle* sehandle, const std::string& path) {
     if (!prepare_dir(sehandle, 0711, 0, 0, path + "/apexdata")) return false;
 
-    auto apex_list = get_apex_list();
-    if (!apex_list.ok()) {
-        LOG(ERROR) << apex_list.error();
+    auto dirp = std::unique_ptr<DIR, int (*)(DIR*)>(opendir("/apex"), closedir);
+    if (!dirp) {
+        PLOG(ERROR) << "Unable to open apex directory";
         return false;
     }
-    for (const auto& name : *apex_list) {
+    struct dirent* entry;
+    while ((entry = readdir(dirp.get())) != nullptr) {
+        if (entry->d_type != DT_DIR) continue;
+
+        const char* name = entry->d_name;
+        // skip any starting with "."
+        if (name[0] == '.') continue;
+
+        if (strchr(name, '@') != NULL) continue;
+
         if (!prepare_dir(sehandle, 0771, AID_ROOT, AID_SYSTEM, path + "/apexdata/" + name)) {
             return false;
         }

From 64d727c5031cceb875b4d11000bcfc0c2efa2bea Mon Sep 17 00:00:00 2001
From: Jooyung Han <jooyung@google.com>
Date: Sat, 12 Aug 2023 00:40:21 +0900
Subject: [PATCH 2/2] Use /data/misc/apexdata for the list of APEXes

vold_prepare_subdirs should create apexdata directories for each APEX.
Previously, it gets the list by scanning /apex directory. However,
vold/vold_prepare_subdirs run in the bootstrap mount namespace, they can
see only bootstrap apexes in /apex. The reason why it worked was that
unintended side effects of how we managed /apex directory for both mount
namespace.

Instead, since apexdata directories are already populated by init in
/data/misc/apexdata, we can use that directory for the same purpose.

Bug: 295345486
Test: CtsPackageSettingHostTestCases
Change-Id: I453cd59f54ccbb140f73b5e8576b36fa49f9bc59
---
 vold_prepare_subdirs.cpp | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/vold_prepare_subdirs.cpp b/vold_prepare_subdirs.cpp
index 60e82f5..e82a7c2 100644
--- a/vold_prepare_subdirs.cpp
+++ b/vold_prepare_subdirs.cpp
@@ -144,7 +144,12 @@ static bool rmrf_contents(const std::string& path) {
 static bool prepare_apex_subdirs(struct selabel_handle* sehandle, const std::string& path) {
     if (!prepare_dir(sehandle, 0711, 0, 0, path + "/apexdata")) return false;
 
-    auto dirp = std::unique_ptr<DIR, int (*)(DIR*)>(opendir("/apex"), closedir);
+    // Since vold/vold_prepare_subdirs run in the bootstrap mount namespace
+    // we can't get the full list of APEXes by scanning /apex directory.
+    // Instead, we can look up /data/misc/apexdata for the list of APEXes,
+    // which is populated during `perform_apex_config` in init.
+    // Note: `init_user0` should be invoked after `perform_apex_config`.
+    auto dirp = std::unique_ptr<DIR, int (*)(DIR*)>(opendir("/data/misc/apexdata"), closedir);
     if (!dirp) {
         PLOG(ERROR) << "Unable to open apex directory";
         return false;
@@ -157,8 +162,6 @@ static bool prepare_apex_subdirs(struct selabel_handle* sehandle, const std::str
         // skip any starting with "."
         if (name[0] == '.') continue;
 
-        if (strchr(name, '@') != NULL) continue;
-
         if (!prepare_dir(sehandle, 0771, AID_ROOT, AID_SYSTEM, path + "/apexdata/" + name)) {
             return false;
         }