Update.

	* sysdeps/unix/sysv/linux/sleep.c (__sleep): Make Unix98 compliant
	by working removing SIG_IGN handler for SIGCHLD if necessary.
	Patch by H.J. Lu <hjl@lucon.org>.

2 files changed, 55 insertions, 3 deletions

diff --git a/ChangeLog b/ChangeLog
index 18914ea140..be1a379dec 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 1998-11-17  Ulrich Drepper  <drepper@cygnus.com>
 
+	* sysdeps/unix/sysv/linux/sleep.c (__sleep): Make Unix98 compliant
+	by working removing SIG_IGN handler for SIGCHLD if necessary.
+	Patch by H.J. Lu <hjl@lucon.org>.
+
 	* stdio-common/printf_fphex.c (__printf_fphex): Correct printing
 	of denormalized numbers.
 
diff --git a/sysdeps/unix/sysv/linux/sleep.c b/sysdeps/unix/sysv/linux/sleep.c
index f67403f694..5fb11603cf 100644
--- a/sysdeps/unix/sysv/linux/sleep.c
+++ b/sysdeps/unix/sysv/linux/sleep.c
@@ -1,5 +1,5 @@
 /* Implementation of the POSIX sleep function using nanosleep.
-   Copyright (C) 1996, 1997 Free Software Foundation, Inc.
+   Copyright (C) 1996, 1997, 1998 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
 
@@ -18,18 +18,66 @@
    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
    Boston, MA 02111-1307, USA.  */
 
+#include <errno.h>
 #include <time.h>
+#include <signal.h>
 #include <unistd.h>
 
+/* We are going to use the `nanosleep' syscall of the kernel.  But the
+   kernel does not implement the sstupid SysV SIGCHLD vs. SIG_IGN
+   behaviour for this syscall.  Therefore we have to emulate it here.  */
 unsigned int
 __sleep (unsigned int seconds)
 {
   struct timespec ts = { tv_sec: (long int) seconds, tv_nsec: 0 };
+  sigset_t set, oset;
+  struct sigaction oact;
   unsigned int result;
 
-  if (__nanosleep (&ts, &ts) == 0)
-    result = 0;
+  /* Linux will wake up the system call, nanosleep, when SIGCHLD
+     arrives even if SIGCHLD is ignored.  We have to deal with it
+     in libc.  We block SIGCHLD first.  */
+  if (__sigemptyset (&set) < 0
+      || __sigaddset (&set, SIGCHLD) < 0
+      || __sigprocmask (SIG_BLOCK, &set, &oset))
+    return -1;
+
+  /* If SIGCHLD is already blocked, we don't have to do anything.  */
+  if (!__sigismember (&oset, SIGCHLD))
+    {
+      int saved_errno;
+
+      /* We get the signal handler for SIGCHLD.  */
+      if (__sigaction (SIGCHLD, (struct sigaction *) NULL, &oact) < 0)
+	{
+	  saved_errno = errno;
+	  /* Restore the original signal mask.  */
+	  (void) __sigprocmask (SIG_SETMASK, &oset, (sigset_t *) NULL);
+	  __set_errno (saved_errno);
+	  return -1;
+	}
+
+      if (oact.sa_handler == SIG_IGN)
+	{
+	  /* We should leave SIGCHLD blocked.  */
+	  result = __nanosleep (&ts, &ts);
+
+	  saved_errno = errno;
+	  /* Restore the original signal mask.  */
+	  (void) __sigprocmask (SIG_SETMASK, &oset, (sigset_t *) NULL);
+	  __set_errno (saved_errno);
+	}
+      else
+	{
+	  /* We should unblock SIGCHLD.  Restore the original signal mask.  */
+	  (void) __sigprocmask (SIG_SETMASK, &oset, (sigset_t *) NULL);
+	  result = __nanosleep (&ts, &ts);
+	}
+    }
   else
+    result = __nanosleep (&ts, &ts);
+
+  if (result != 0)
     /* Round remaining time.  */
     result = (unsigned int) ts.tv_sec + (ts.tv_nsec >= 500000000L);