init: move reaping from ServiceManager to signal_handler.cpp

signal_handler.cpp itself needs to be cleaned up, but this is a step
to clean up ServiceManager.

Test: boot bullhead
Change-Id: I81f1e8ac4d09692cfb364bc702cbd3deb61aa55a

1 files changed, 72 insertions, 2 deletions

diff --git a/init/signal_handler.cpp b/init/signal_handler.cpp
index db1bfcf8c..d77a2123b 100644
--- a/init/signal_handler.cpp
+++ b/init/signal_handler.cpp
@@ -14,29 +14,94 @@
  * limitations under the License.
  */
 
+#include "signal_handler.h"
+
 #include <signal.h>
 #include <string.h>
 #include <sys/socket.h>
 #include <sys/types.h>
+#include <sys/wait.h>
 #include <unistd.h>
 
+#include <android-base/chrono_utils.h>
 #include <android-base/logging.h>
+#include <android-base/scopeguard.h>
+#include <android-base/stringprintf.h>
 
 #include "init.h"
+#include "property_service.h"
 #include "service.h"
 
+using android::base::StringPrintf;
+using android::base::boot_clock;
+using android::base::make_scope_guard;
+
 namespace android {
 namespace init {
 
 static int signal_write_fd = -1;
 static int signal_read_fd = -1;
 
+static bool ReapOneProcess() {
+    siginfo_t siginfo = {};
+    // This returns a zombie pid or informs us that there are no zombies left to be reaped.
+    // It does NOT reap the pid; that is done below.
+    if (TEMP_FAILURE_RETRY(waitid(P_ALL, 0, &siginfo, WEXITED | WNOHANG | WNOWAIT)) != 0) {
+        PLOG(ERROR) << "waitid failed";
+        return false;
+    }
+
+    auto pid = siginfo.si_pid;
+    if (pid == 0) return false;
+
+    // At this point we know we have a zombie pid, so we use this scopeguard to reap the pid
+    // whenever the function returns from this point forward.
+    // We do NOT want to reap the zombie earlier as in Service::Reap(), we kill(-pid, ...) and we
+    // want the pid to remain valid throughout that (and potentially future) usages.
+    auto reaper = make_scope_guard([pid] { TEMP_FAILURE_RETRY(waitpid(pid, nullptr, WNOHANG)); });
+
+    if (PropertyChildReap(pid)) return true;
+
+    Service* service = ServiceManager::GetInstance().FindServiceByPid(pid);
+
+    std::string name;
+    std::string wait_string;
+    if (service) {
+        name = StringPrintf("Service '%s' (pid %d)", service->name().c_str(), pid);
+        if (service->flags() & SVC_EXEC) {
+            auto exec_duration = boot_clock::now() - service->time_started();
+            auto exec_duration_ms =
+                std::chrono::duration_cast<std::chrono::milliseconds>(exec_duration).count();
+            wait_string = StringPrintf(" waiting took %f seconds", exec_duration_ms / 1000.0f);
+        }
+    } else {
+        name = StringPrintf("Untracked pid %d", pid);
+    }
+
+    auto status = siginfo.si_status;
+    if (WIFEXITED(status)) {
+        LOG(INFO) << name << " exited with status " << WEXITSTATUS(status) << wait_string;
+    } else if (WIFSIGNALED(status)) {
+        LOG(INFO) << name << " killed by signal " << WTERMSIG(status) << wait_string;
+    }
+
+    if (!service) return true;
+
+    service->Reap();
+
+    if (service->flags() & SVC_TEMPORARY) {
+        ServiceManager::GetInstance().RemoveService(*service);
+    }
+
+    return true;
+}
+
 static void handle_signal() {
     // Clear outstanding requests.
     char buf[32];
     read(signal_read_fd, buf, sizeof(buf));
 
-    ServiceManager::GetInstance().ReapAnyOutstandingChildren();
+    ReapAnyOutstandingChildren();
 }
 
 static void SIGCHLD_handler(int) {
@@ -45,6 +110,11 @@ static void SIGCHLD_handler(int) {
     }
 }
 
+void ReapAnyOutstandingChildren() {
+    while (ReapOneProcess()) {
+    }
+}
+
 void signal_handler_init() {
     // Create a signalling mechanism for SIGCHLD.
     int s[2];
@@ -63,7 +133,7 @@ void signal_handler_init() {
     act.sa_flags = SA_NOCLDSTOP;
     sigaction(SIGCHLD, &act, 0);
 
-    ServiceManager::GetInstance().ReapAnyOutstandingChildren();
+    ReapAnyOutstandingChildren();
 
     register_epoll_handler(signal_read_fd, handle_signal);
 }