init: Cleanly exit subcontext processes upon init's death
This change makes the subcontext processes cleanly exit in the event of
the init's socket being closed. If that was an accident, init will
respawn the process immediately. Otherwise, it will just quietly go
away.
Bug: 80425914
Test: kill -9 $INIT_PID # Outside of an Android container
Change-Id: I664f11d1b3700ea46857abf24857335fe28e92fa
diff --git a/init/subcontext.cpp b/init/subcontext.cpp
index c2a21d4..092c51c 100644
--- a/init/subcontext.cpp
+++ b/init/subcontext.cpp
@@ -62,7 +62,9 @@
Result<std::string> ReadMessage(int socket) {
char buffer[kBufferSize] = {};
auto result = TEMP_FAILURE_RETRY(recv(socket, buffer, sizeof(buffer), 0));
- if (result <= 0) {
+ if (result == 0) {
+ return Error();
+ } else if (result < 0) {
return ErrnoError();
}
return std::string(buffer, result);
@@ -175,6 +177,12 @@
auto init_message = ReadMessage(init_fd_);
if (!init_message) {
+ if (init_message.error_errno() == 0) {
+ // If the init file descriptor was closed, let's exit quietly. If
+ // this was accidental, init will restart us. If init died, this
+ // avoids calling abort(3) unnecessarily.
+ return;
+ }
LOG(FATAL) << "Could not read message from init: " << init_message.error();
}