commit 9581394d6886923dca3f450a7fcd803c8d985eef
author Tom Cherry <tomcherry@google.com> Tue Apr 28 13:55:19 2020 -0700
committer Tom Cherry <tomcherry@google.com> Wed Apr 29 08:41:21 2020 -0700
tree 56a9857cd43ad5fe831cbdd52080149518bbb574
parent 9477d1246e5013259b53f7abcd0f4de4f779431b

init: fix restarting of subcontext

When the subcontext code was redone to allow only one subcontext
(vendor_init), the code for restarting it and for terminating it
during shutdown was not updated, resulting in it not working.

Bug: 155203339
Test: kill subcontext init and notice it restart
Test: subcontext init stops during shutdown
Merged-In: Ib77f59d1e7be0ffcfd3f31c8450dc022c20bb322
Change-Id: Ib77f59d1e7be0ffcfd3f31c8450dc022c20bb322
(cherry picked from commit e3e77d382fd1e1dbb2acb777658064e78be94237)

init/init.cpp

diff --git a/init/init.cpp b/init/init.cpp
index cadd5c5..6465df1 100644
--- a/init/init.cpp
+++ b/init/init.cpp
@@ -75,6 +75,7 @@
 #include "service.h"
 #include "service_parser.h"
 #include "sigchld_handler.h"
+#include "subcontext.h"
 #include "system/core/init/property_service.pb.h"
 #include "util.h"
 
@@ -99,8 +100,6 @@
 static int signal_fd = -1;
 static int property_fd = -1;
 
-static std::unique_ptr<Subcontext> subcontext;
-
 struct PendingControlMessage {
     std::string message;
     std::string name;
@@ -253,9 +252,8 @@
     Parser parser;
 
     parser.AddSectionParser("service", std::make_unique<ServiceParser>(
-                                               &service_list, subcontext.get(), std::nullopt));
-    parser.AddSectionParser("on",
-                            std::make_unique<ActionParser>(&action_manager, subcontext.get()));
+                                               &service_list, GetSubcontext(), std::nullopt));
+    parser.AddSectionParser("on", std::make_unique<ActionParser>(&action_manager, GetSubcontext()));
     parser.AddSectionParser("import", std::make_unique<ImportParser>(&parser));
 
     return parser;
@@ -265,9 +263,9 @@
 Parser CreateServiceOnlyParser(ServiceList& service_list, bool from_apex) {
     Parser parser;
 
-    parser.AddSectionParser("service",
-                            std::make_unique<ServiceParser>(&service_list, subcontext.get(),
-                                                            std::nullopt, from_apex));
+    parser.AddSectionParser(
+            "service", std::make_unique<ServiceParser>(&service_list, GetSubcontext(), std::nullopt,
+                                                       from_apex));
     return parser;
 }
 
@@ -783,7 +781,7 @@
         PLOG(FATAL) << "SetupMountNamespaces failed";
     }
 
-    subcontext = InitializeSubcontext();
+    InitializeSubcontext();
 
     ActionManager& am = ActionManager::GetInstance();
     ServiceList& sm = ServiceList::GetInstance();

init/subcontext.cpp

diff --git a/init/subcontext.cpp b/init/subcontext.cpp
index 5263c14..f3dd538 100644
--- a/init/subcontext.cpp
+++ b/init/subcontext.cpp
@@ -52,6 +52,8 @@
 namespace {
 
 std::string shutdown_command;
+static bool subcontext_terminated_by_shutdown;
+static std::unique_ptr<Subcontext> subcontext;
 
 class SubcontextProcess {
   public:
@@ -323,34 +325,30 @@
     return expanded_args;
 }
 
-static std::vector<Subcontext> subcontexts;
-static bool shutting_down;
-
-std::unique_ptr<Subcontext> InitializeSubcontext() {
+void InitializeSubcontext() {
     if (SelinuxGetVendorAndroidVersion() >= __ANDROID_API_P__) {
-        return std::make_unique<Subcontext>(std::vector<std::string>{"/vendor", "/odm"},
-                                            kVendorContext);
+        subcontext.reset(
+                new Subcontext(std::vector<std::string>{"/vendor", "/odm"}, kVendorContext));
     }
-    return nullptr;
+}
+
+Subcontext* GetSubcontext() {
+    return subcontext.get();
 }
 
 bool SubcontextChildReap(pid_t pid) {
-    for (auto& subcontext : subcontexts) {
-        if (subcontext.pid() == pid) {
-            if (!shutting_down) {
-                subcontext.Restart();
-            }
-            return true;
+    if (subcontext->pid() == pid) {
+        if (!subcontext_terminated_by_shutdown) {
+            subcontext->Restart();
         }
+        return true;
     }
     return false;
 }
 
 void SubcontextTerminate() {
-    shutting_down = true;
-    for (auto& subcontext : subcontexts) {
-        kill(subcontext.pid(), SIGTERM);
-    }
+    subcontext_terminated_by_shutdown = true;
+    kill(subcontext->pid(), SIGTERM);
 }
 
 }  // namespace init

init/subcontext.h

diff --git a/init/subcontext.h b/init/subcontext.h
index 5e1d8a8..788d3be 100644
--- a/init/subcontext.h
+++ b/init/subcontext.h
@@ -60,7 +60,8 @@
 };
 
 int SubcontextMain(int argc, char** argv, const BuiltinFunctionMap* function_map);
-std::unique_ptr<Subcontext> InitializeSubcontext();
+void InitializeSubcontext();
+Subcontext* GetSubcontext();
 bool SubcontextChildReap(pid_t pid);
 void SubcontextTerminate();