From bee9f5718bd2dfedb615767bbd25147b4f3eed15 Mon Sep 17 00:00:00 2001
From: Suren Baghdasaryan <surenb@google.com>
Date: Tue, 5 Feb 2019 16:44:22 -0800
Subject: [PATCH] libprocessgroup: Disable file descriptor caching temporarily

File descriptor caching breaks boot on Android Go and Svelte targets.
Disable it temporarily to fix the builds and investigate the root cause
further.

Bug: 123868658
Test: Android Go device boots after this change

Change-Id: Idd0209029cde8454ea99b9de030f7a317c2988d7
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
---
 libprocessgroup/task_profiles.cpp | 32 +++++++++++++++++++++++++++++++
 libprocessgroup/task_profiles.h   |  2 ++
 2 files changed, 34 insertions(+)

diff --git a/libprocessgroup/task_profiles.cpp b/libprocessgroup/task_profiles.cpp
index ec6cbbc45..447852d7f 100644
--- a/libprocessgroup/task_profiles.cpp
+++ b/libprocessgroup/task_profiles.cpp
@@ -132,6 +132,7 @@ bool SetCgroupAction::IsAppDependentPath(const std::string& path) {
 
 SetCgroupAction::SetCgroupAction(const CgroupController* c, const std::string& p)
     : controller_(c), path_(p) {
+#ifdef CACHE_FILE_DESCRIPTORS
     // cache file descriptor only if path is app independent
     if (IsAppDependentPath(path_)) {
         // file descriptor is not cached
@@ -155,6 +156,7 @@ SetCgroupAction::SetCgroupAction(const CgroupController* c, const std::string& p
     }
 
     fd_ = std::move(fd);
+#endif
 }
 
 bool SetCgroupAction::AddTidToCgroup(int tid, int fd) {
@@ -176,6 +178,7 @@ bool SetCgroupAction::AddTidToCgroup(int tid, int fd) {
 }
 
 bool SetCgroupAction::ExecuteForProcess(uid_t uid, pid_t pid) const {
+#ifdef CACHE_FILE_DESCRIPTORS
     if (fd_ >= 0) {
         // fd is cached, reuse it
         if (!AddTidToCgroup(pid, fd_)) {
@@ -203,9 +206,24 @@ bool SetCgroupAction::ExecuteForProcess(uid_t uid, pid_t pid) const {
     }
 
     return true;
+#else
+    std::string procs_path = controller_->GetProcsFilePath(path_.c_str(), uid, pid);
+    unique_fd tmp_fd(TEMP_FAILURE_RETRY(open(procs_path.c_str(), O_WRONLY | O_CLOEXEC)));
+    if (tmp_fd < 0) {
+        // no permissions to access the file, ignore
+        return true;
+    }
+    if (!AddTidToCgroup(pid, tmp_fd)) {
+        PLOG(ERROR) << "Failed to add task into cgroup";
+        return false;
+    }
+
+    return true;
+#endif
 }
 
 bool SetCgroupAction::ExecuteForTask(int tid) const {
+#ifdef CACHE_FILE_DESCRIPTORS
     if (fd_ >= 0) {
         // fd is cached, reuse it
         if (!AddTidToCgroup(tid, fd_)) {
@@ -223,6 +241,20 @@ bool SetCgroupAction::ExecuteForTask(int tid) const {
     // application-dependent path can't be used with tid
     PLOG(ERROR) << "Application profile can't be applied to a thread";
     return false;
+#else
+    std::string tasks_path = controller_->GetTasksFilePath(path_.c_str());
+    unique_fd tmp_fd(TEMP_FAILURE_RETRY(open(tasks_path.c_str(), O_WRONLY | O_CLOEXEC)));
+    if (tmp_fd < 0) {
+        // no permissions to access the file, ignore
+        return true;
+    }
+    if (!AddTidToCgroup(tid, tmp_fd)) {
+        PLOG(ERROR) << "Failed to add task into cgroup";
+        return false;
+    }
+
+    return true;
+#endif
 }
 
 bool TaskProfile::ExecuteForProcess(uid_t uid, pid_t pid) const {
diff --git a/libprocessgroup/task_profiles.h b/libprocessgroup/task_profiles.h
index 83e74b20b..b2e39f944 100644
--- a/libprocessgroup/task_profiles.h
+++ b/libprocessgroup/task_profiles.h
@@ -117,7 +117,9 @@ class SetCgroupAction : public ProfileAction {
   private:
     const CgroupController* controller_;
     std::string path_;
+#ifdef CACHE_FILE_DESCRIPTORS
     android::base::unique_fd fd_;
+#endif
 
     static bool IsAppDependentPath(const std::string& path);
     static bool AddTidToCgroup(int tid, int fd);