From: Juergen Perlinger <perlinger@ntp.org>
Date: Sun, 4 Sep 2016 15:37:34 +0000 (+0200)
Subject: [Bug 3050] Fix for bug #2960 causes sntp to print a spurious error message
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=586eee721ee5c90467c7729e12cc276dc2b0eaef;p=thirdparty%2Fntp.git

[Bug 3050] Fix for bug #2960 causes sntp to print a spurious error message

bk: 57cc3fbe0gjFzc9fMfCLk_f5YZgEkA
---

diff --git a/ChangeLog b/ChangeLog
index 0805467dc..a220c0c94 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+---
+* [Bug 3050]  Fix for bug #2960 causes [...] spurious error message.
+  <perlinger@ntp.org>
+  - patches by Reinhard Max <max@suse.com> and Havard Eidnes <he@uninett.no>
+
 ---
 (4.2.8p8) 2016/06/02 Released by Harlan Stenn <stenn@ntp.org>
 
diff --git a/libntp/work_fork.c b/libntp/work_fork.c
index 6c9545aa9..8223fdd2f 100644
--- a/libntp/work_fork.c
+++ b/libntp/work_fork.c
@@ -114,18 +114,24 @@ interrupt_worker_sleep(void)
 
 /*
  * harvest_child_status() runs in the parent.
+ *
+ * Note the error handling -- this is an interaction with SIGCHLD.
+ * SIG_IGN on SIGCHLD on some OSes means do not wait but reap
+ * automatically. Since we're not really interested in the result code,
+ * we simply ignore the error.
  */
 static void
 harvest_child_status(
 	blocking_child *	c
 	)
 {
-	if (c->pid)
-	{
+	if (c->pid) {
 		/* Wait on the child so it can finish terminating */
 		if (waitpid(c->pid, NULL, 0) == c->pid)
 			TRACE(4, ("harvested child %d\n", c->pid));
-		else msyslog(LOG_ERR, "error waiting on child %d: %m", c->pid);
+		else if (errno != ECHILD)
+			msyslog(LOG_ERR, "error waiting on child %d: %m", c->pid);
+		c->pid = 0;
 	}
 }
 
@@ -162,7 +168,6 @@ cleanup_after_child(
 		close(c->resp_read_pipe);
 		c->resp_read_pipe = -1;
 	}
-	c->pid = 0;
 	c->resp_read_ctx = NULL;
 	DEBUG_INSIST(-1 == c->req_read_pipe);
 	DEBUG_INSIST(-1 == c->resp_write_pipe);
@@ -461,7 +466,10 @@ fork_blocking_child(
 	fflush(stdout);
 	fflush(stderr);
 
-	signal_no_reset(SIGCHLD, SIG_IGN);
+	/* [BUG 3050] setting SIGCHLD to SIG_IGN likely causes unwanted
+	 * or undefined effects. We don't do it and leave SIGCHLD alone.
+	 */
+	/* signal_no_reset(SIGCHLD, SIG_IGN); */
 
 	childpid = fork();
 	if (-1 == childpid) {