MC: Reap all zombie childs to avoid them to accumulate

[simgrid.git] / src / mc / remote / AppSide.cpp

diff --git a/src/mc/remote/AppSide.cpp b/src/mc/remote/AppSide.cpp
index 18315d3efbe359644a4afb2656efeeef23acf961..b66d7a10ce5275c43c8192aaa6b8dacd2d13a327 100644 (file)
--- a/src/mc/remote/AppSide.cpp
+++ b/src/mc/remote/AppSide.cpp
@@ -152,7 +152,13 @@ void AppSide::handle_finalize(const s_mc_message_int_t* msg) const
 }
 void AppSide::handle_fork(const s_mc_message_int_t* msg)
 {
-  int pid = fork();
+  int status;
+  int pid;
+  /* Reap any zombie child, saving its status for later use in AppSide::handle_wait_child() */
+  while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
+    child_statuses_[pid] = status;
+
+  pid = fork();
   xbt_assert(pid >= 0, "Could not fork application sub-process: %s.", strerror(errno));
 
   if (pid == 0) { // Child
@@ -179,14 +185,19 @@ void AppSide::handle_fork(const s_mc_message_int_t* msg)
     answer.value              = getpid();
     xbt_assert(channel_.send(answer) == 0, "Could not send response to WAIT_CHILD_REPLY: %s", strerror(errno));
   } else {
-    XBT_DEBUG("App %d forks subprocess %d.", getpid(), pid);
+    XBT_VERB("App %d forks subprocess %d.", getpid(), pid);
   }
 }
 void AppSide::handle_wait_child(const s_mc_message_int_t* msg)
 {
   int status;
   errno = 0;
-  waitpid(msg->value, &status, 0);
+  if (auto search = child_statuses_.find(msg->value); search != child_statuses_.end()) {
+    status = search->second;
+    child_statuses_.erase(search); // We only need this info once
+  } else {
+    waitpid(msg->value, &status, 0);
+  }
   xbt_assert(errno == 0, "Cannot wait on behalf of the checker: %s.", strerror(errno));
 
   s_mc_message_int_t answer = {};