# HG changeset patch
# User jbe
# Date 1497732224 -7200
# Node ID dd0ec48592e70930fe550a683ea9584060686500
# Parent  ce109800ae2dd5ae7ff32ae0f32dd083e7d0246b
Bugfix regarding waiting for child processes in moonbridge_io.poll(...)

diff -r ce109800ae2d -r dd0ec48592e7 moonbridge_io.c
--- a/moonbridge_io.c	Sat Jun 17 22:35:44 2017 +0200
+++ b/moonbridge_io.c	Sat Jun 17 22:43:44 2017 +0200
@@ -117,6 +117,7 @@
 } moonbr_io_child_t;
 
 volatile sig_atomic_t moonbr_io_sigterm_flag = 0;
+volatile sig_atomic_t moonbr_io_sigchld_flag = 0;
 
 static int moonbr_io_yield(lua_State *L) {
   return lua_yield(L, lua_gettop(L));
@@ -1615,6 +1616,10 @@
   moonbr_io_sigterm_flag = 1;
 }
 
+static void moonbr_io_sigchld_handler(int sig) {
+  moonbr_io_sigchld_flag = 1;
+}
+
 int moonbr_io_catch_sigterm(lua_State *L) {
   signal(SIGTERM, moonbr_io_sigterm_handler);
   return 0;
@@ -1665,7 +1670,7 @@
   int force_wakeup = 0;
   int use_timeout = 0;  // negative for negative timeout
   int check_sigterm = 0;
-  int check_child = 0;
+  int check_sigchld = 0;
   int childstatus;
   sigset_t mask, orig_mask;
   int status;
@@ -1698,7 +1703,11 @@
           } else {
             child = luaL_testudata(L, -2, MOONBR_IO_CHILD_MT_REGKEY);
             if (child) {
-              check_child = 1;
+              if (!check_sigchld) {
+                check_sigchld = 1;
+                moonbr_io_sigchld_flag = 0;
+                signal(SIGCHLD, moonbr_io_sigchld_handler);
+              }
               if (waitpid(child->pid, &childstatus, WNOHANG|WNOWAIT) != -1) {
                 force_wakeup = 1;
               } else if (errno != ECHILD && errno != EINTR) {
@@ -1758,10 +1767,10 @@
   if (use_timeout < 0) force_wakeup = 1;
   if (!lua_isnoneornil(L, 4)) luaL_checktype(L, 4, LUA_TBOOLEAN);
   check_sigterm = lua_toboolean(L, 4);
-  if ((check_sigterm || check_child) && !force_wakeup) {
+  if ((check_sigterm || check_sigchld) && !force_wakeup) {
     sigemptyset(&mask);
     if (check_sigterm) sigaddset(&mask, SIGTERM);
-    if (check_child) sigaddset(&mask, SIGCHLD);
+    if (check_sigchld) sigaddset(&mask, SIGCHLD);
     if (sigprocmask(SIG_BLOCK, &mask, &orig_mask)) abort();
   }
   if (check_sigterm && moonbr_io_sigterm_flag) {
@@ -1773,15 +1782,9 @@
     lua_pushboolean(L, 1);
     return 3;
   }
-  if (check_child && !force_wakeup) {
-    if (wait3(&childstatus, WNOHANG|WNOWAIT, NULL) != -1) {
-      if (sigprocmask(SIG_SETMASK, &orig_mask, NULL)) abort();
-      force_wakeup = 1;
-    } else if (errno != ECHILD && errno != EINTR) {
-      moonbr_io_prepare_errmsg();
-      if (sigprocmask(SIG_SETMASK, &orig_mask, NULL)) abort();
-      luaL_error(L, "Error in waitpid call: %s", errmsg);
-    }
+  if (check_sigchld && !force_wakeup && moonbr_io_sigchld_flag) {
+    if (sigprocmask(SIG_SETMASK, &orig_mask, NULL)) abort();
+    force_wakeup = 1;
   }
   if (use_timeout < 0) {
     lua_pushboolean(L, 0);