vcl: cleanup children that use _exit()

Change-Id: Ia56c2698adb0ea7811203844dc4db10e121fbc42
Signed-off-by: Florin Coras <fcoras@cisco.com>

1 files changed, 95 insertions, 11 deletions

diff --git a/src/vcl/vppcom.c b/src/vcl/vppcom.c
index bf21f5204b4..07136e9c6c8 100644
--- a/src/vcl/vppcom.c
+++ b/src/vcl/vppcom.c
@@ -697,14 +697,96 @@ vcl_cleanup_bapi (void)
   vl_client_api_unmap ();
 }
 
-void
+static void
+vcl_cleanup_forked_child (vcl_worker_t * wrk, vcl_worker_t * child_wrk)
+{
+  vcl_worker_t *sub_child;
+  int tries = 0;
+
+  if (child_wrk->forked_child != ~0)
+    {
+      sub_child = vcl_worker_get_if_valid (child_wrk->forked_child);
+      if (sub_child)
+	{
+	  /* Wait a bit, maybe the process is going away */
+	  while (kill (sub_child->current_pid, 0) >= 0 && tries++ < 50)
+	    usleep (1e3);
+	  if (kill (sub_child->current_pid, 0) < 0)
+	    vcl_cleanup_forked_child (child_wrk, sub_child);
+	}
+    }
+  vcl_worker_cleanup (child_wrk, 1 /* notify vpp */ );
+  VDBG (0, "Cleaned up wrk %u", child_wrk->wrk_index);
+  wrk->forked_child = ~0;
+}
+
+static struct sigaction old_sa;
+
+static void
+vcl_intercept_sigchld_handler (int signum, siginfo_t * si, void *uc)
+{
+  vcl_worker_t *wrk, *child_wrk;
+
+  if (vcl_get_worker_index () == ~0)
+    return;
+
+  sigaction (SIGCHLD, &old_sa, 0);
+
+  wrk = vcl_worker_get_current ();
+  if (wrk->forked_child == ~0)
+    return;
+
+  child_wrk = vcl_worker_get_if_valid (wrk->forked_child);
+  if (si->si_pid != child_wrk->current_pid)
+    {
+      VDBG (0, "unexpected child pid %u", si->si_pid);
+      return;
+    }
+  if (child_wrk)
+    vcl_cleanup_forked_child (wrk, child_wrk);
+
+  if (old_sa.sa_flags & SA_SIGINFO)
+    {
+      void (*fn) (int, siginfo_t *, void *) = old_sa.sa_sigaction;
+      fn (signum, si, uc);
+    }
+  else
+    {
+      void (*fn) (int) = old_sa.sa_handler;
+      if (fn)
+	fn (signum);
+    }
+}
+
+static void
+vcl_incercept_sigchld ()
+{
+  struct sigaction sa;
+  clib_memset (&sa, 0, sizeof (sa));
+  sa.sa_sigaction = vcl_intercept_sigchld_handler;
+  sa.sa_flags = SA_SIGINFO;
+  if (sigaction (SIGCHLD, &sa, &old_sa))
+    {
+      VERR ("couldn't intercept sigchld");
+      exit (-1);
+    }
+}
+
+static void
+vcl_app_pre_fork (void)
+{
+  vcl_incercept_sigchld ();
+}
+
+static void
 vcl_app_fork_child_handler (void)
 {
+  int rv, parent_wrk_index;
+  vcl_worker_t *parent_wrk;
   u8 *child_name;
-  int rv, parent_wrk;
 
-  parent_wrk = vcl_get_worker_index ();
-  VDBG (0, "initializing forked child with parent wrk %u", parent_wrk);
+  parent_wrk_index = vcl_get_worker_index ();
+  VDBG (0, "initializing forked child with parent wrk %u", parent_wrk_index);
 
   /*
    * Allocate worker
@@ -732,17 +814,18 @@ vcl_app_fork_child_handler (void)
    * Register worker with vpp and share sessions
    */
   vcl_worker_register_with_vpp ();
+  parent_wrk = vcl_worker_get (parent_wrk_index);
   vcl_worker_share_sessions (parent_wrk);
+  parent_wrk->forked_child = vcl_get_worker_index ();
 
   VDBG (0, "forked child main worker initialized");
   vcm->forking = 0;
 }
 
-void
+static void
 vcl_app_fork_parent_handler (void)
 {
   vcm->forking = 1;
-
   while (vcm->forking)
     ;
 }
@@ -759,8 +842,8 @@ vppcom_app_exit (void)
 {
   if (!pool_elts (vcm->workers))
     return;
-
-  vcl_worker_cleanup (1 /* notify vpp */ );
+  vcl_worker_cleanup (vcl_worker_get_current (), 1 /* notify vpp */ );
+  vcl_set_worker_index (~0);
   vcl_elog_stop (vcm);
   if (vec_len (vcm->workers) == 1)
     vl_client_disconnect_from_vlib ();
@@ -796,7 +879,7 @@ vppcom_app_create (char *app_name)
   pool_alloc (vcm->workers, vcl_cfg->max_workers);
   clib_spinlock_init (&vcm->workers_lock);
   clib_rwlock_init (&vcm->segment_table_lock);
-  pthread_atfork (NULL, vcl_app_fork_parent_handler,
+  pthread_atfork (vcl_app_pre_fork, vcl_app_fork_parent_handler,
 		  vcl_app_fork_child_handler);
   atexit (vppcom_app_exit);
 
@@ -857,13 +940,14 @@ vppcom_app_destroy (void)
 	VDBG (0, "application detach timed out! returning %d (%s)", rv,
 	      vppcom_retval_str (rv));
       vec_free (vcm->app_name);
-      vcl_worker_cleanup (0 /* notify vpp */ );
+      vcl_worker_cleanup (vcl_worker_get_current (), 0 /* notify vpp */ );
     }
   else
     {
-      vcl_worker_cleanup (1 /* notify vpp */ );
+      vcl_worker_cleanup (vcl_worker_get_current (), 1 /* notify vpp */ );
     }
 
+  vcl_set_worker_index (~0);
   vcl_elog_stop (vcm);
   vl_client_disconnect_from_vlib ();
 }