svn commit: r252606 - stable/9/bin/sleep

[Jilles Tjoelker]

Author: jilles
Date: Wed Jul  3 21:11:56 2013
New Revision: 252606
URL: http://svnweb.freebsd.org/changeset/base/252606

Log:
  MFC r251078,r251433: sleep: Improve nanosleep() error handling:
  
   * Work around kernel bugs that cause a spurious [EINTR] return if a
     debugger (such as truss(1)) is attached.
  
   * Write an error message if an error other than [EINTR] occurs.
  
  PR:		bin/178664

Modified:
  stable/9/bin/sleep/sleep.c
Directory Properties:
  stable/9/bin/sleep/   (props changed)

Modified: stable/9/bin/sleep/sleep.c
==============================================================================
--- stable/9/bin/sleep/sleep.c	Wed Jul  3 21:07:02 2013	(r252605)
+++ stable/9/bin/sleep/sleep.c	Wed Jul  3 21:11:56 2013	(r252606)
@@ -43,6 +43,7 @@ __FBSDID("$FreeBSD$");
 
 #include <ctype.h>
 #include <err.h>
+#include <errno.h>
 #include <limits.h>
 #include <signal.h>
 #include <stdint.h>
@@ -81,14 +82,20 @@ main(int argc, char *argv[])
 	time_to_sleep.tv_nsec = 1e9 * (d - time_to_sleep.tv_sec);
 
 	signal(SIGINFO, report_request);
+
+	/*
+	 * Note: [EINTR] is supposed to happen only when a signal was handled
+	 * but the kernel also returns it when a ptrace-based debugger
+	 * attaches. This is a bug but it is hard to fix.
+	 */
 	while (nanosleep(&time_to_sleep, &time_to_sleep) != 0) {
 		if (report_requested) {
 			/* Reporting does not bother with nanoseconds. */
 			warnx("about %d second(s) left out of the original %d",
 			    (int)time_to_sleep.tv_sec, (int)original);
 			report_requested = 0;
-		} else
-			break;
+		} else if (errno != EINTR)
+			err(1, "nanosleep");
 	}
 	return (0);
 }