Implement the WCONTINUED flag to the wait(2) family of syscalls and the

associated WIFCONTINUED macro as per 1003.1-2001.  Adapted from FreeBSD.
A minor amount of trickiness is involved here.  The value for WCONTINUED
is chosen in such a way that _WSTATUS(_WCONTINUED) == _WSTOPPED and the
WIFSTOPPED macro has been modified such that WIFSTOPPED(_WCONTINUED) !=
_WSTOPPED.  This means we don't need to add an extra check to the
WIFSIGNALED and WIFSTOPPED macros.  deraadt@ OK.

lib/libc/sys/wait.2

@@ -1,4 +1,4 @@
-.\"	$OpenBSD: wait.2,v 1.15 2003/06/02 20:18:39 millert Exp $
+.\"	$OpenBSD: wait.2,v 1.16 2003/08/03 19:25:49 millert Exp $
 .\"	$NetBSD: wait.2,v 1.6 1995/02/27 12:39:37 cgd Exp $
 .\"
 .\" Copyright (c) 1980, 1991, 1993, 1994
@@ -102,18 +102,23 @@ The
 .Fa options
 parameter contains the bitwise
 .Tn OR
-of any of the following options.
-The
-.Dv WNOHANG
-option is used to indicate that the call should not block if
-there are no processes that wish to report status.
-If the
-.Dv WUNTRACED
-option is set, children of the current process that are stopped due to a
+of any of the following options:
+.Bl -tag -width Ds
+.It Dv WCONTINUED
+Causes status to be reported for stopped child processes that have been
+continued by receipt of a
+.Dv SIGCONT
+signal.
+.It Dv WNOHANG
+Indicates that the call should not block if there are no processes that wish
+to report status.
+.It Dv WUNTRACED
+If set, children of the current process that are stopped due to a
 .Dv SIGTTIN , SIGTTOU , SIGTSTP ,
 or
 .Dv SIGSTOP
 signal also have their status reported.
+.El
 .Pp
 If
 .Fa rusage
@@ -146,6 +151,12 @@ value of \-1.
 The following macros may be used to test the manner of exit of the process.
 One of the first three macros will evaluate to a non-zero (true) value:
 .Bl -tag -width Ds
+.It Fn WIFCONTINUED status
+True if the process has not terminated, and has continued after a job
+control stop.
+This macro can be true only if the wait call specified the
+.Dv WCONTINUED
+option).
 .It Fn WIFEXITED status
 True if the process terminated normally by a call to
 .Xr _exit 2

sys/kern/kern_exit.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_exit.c,v 1.46 2003/07/21 22:44:50 tedu Exp $	*/
+/*	$OpenBSD: kern_exit.c,v 1.47 2003/08/03 19:25:49 millert Exp $	*/
 /*	$NetBSD: kern_exit.c,v 1.39 1996/04/22 01:38:25 christos Exp $	*/
 
 /*
@@ -397,7 +397,7 @@ sys_wait4(q, v, retval)
 
 	if (SCARG(uap, pid) == 0)
 		SCARG(uap, pid) = -q->p_pgid;
-	if (SCARG(uap, options) &~ (WUNTRACED|WNOHANG|WALTSIG))
+	if (SCARG(uap, options) &~ (WUNTRACED|WNOHANG|WALTSIG|WCONTINUED))
 		return (EINVAL);
 
 loop:
@@ -468,6 +468,18 @@ sys_wait4(q, v, retval)
 				error = 0;
 			return (error);
 		}
+		if ((SCARG(uap, options) & WCONTINUED) && (p->p_flag & P_CONTINUED)) {
+			p->p_flag &= ~P_CONTINUED;
+			retval[0] = p->p_pid;
+
+			if (SCARG(uap, status)) {
+				status = _WCONTINUED;
+				error = copyout(&status, SCARG(uap, status),
+				    sizeof(status));
+			} else
+				error = 0;
+			return (error);
+		}
 	}
 	if (nfound == 0)
 		return (ECHILD);

sys/kern/kern_sig.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_sig.c,v 1.64 2003/07/21 22:44:50 tedu Exp $	*/
+/*	$OpenBSD: kern_sig.c,v 1.65 2003/08/03 19:25:49 millert Exp $	*/
 /*	$NetBSD: kern_sig.c,v 1.54 1996/04/22 01:38:32 christos Exp $	*/
 
 /*
@@ -818,8 +818,10 @@ psignal(p, signum)
 	if (prop & SA_CONT)
 		p->p_siglist &= ~stopsigmask;
 
-	if (prop & SA_STOP)
+	if (prop & SA_STOP) {
 		p->p_siglist &= ~contsigmask;
+		p->p_flag &= ~P_CONTINUED;
+	}
 
 	p->p_siglist |= mask;
 
@@ -907,6 +909,8 @@ psignal(p, signum)
 			 * an event, then it goes back to run state.
 			 * Otherwise, process goes back to sleep state.
 			 */
+			p->p_flag |= P_CONTINUED;
+			wakeup(p->p_pptr);
 			if (action == SIG_DFL)
 				p->p_siglist &= ~mask;
 			if (action == SIG_CATCH)

sys/sys/proc.h

@@ -1,4 +1,4 @@
-/*	$OpenBSD: proc.h,v 1.65 2003/06/21 00:42:58 tedu Exp $	*/
+/*	$OpenBSD: proc.h,v 1.66 2003/08/03 19:25:49 millert Exp $	*/
 /*	$NetBSD: proc.h,v 1.44 1996/04/22 01:23:21 christos Exp $	*/
 
 /*-
@@ -255,12 +255,13 @@ struct	proc {
 #define	P_NOZOMBIE	0x100000	/* Pid 1 waits for me instead of dad */
 #define P_INEXEC	0x200000	/* Process is doing an exec right now */
 #define P_SYSTRACE	0x400000	/* Process system call tracing active*/
+#define P_CONTINUED	0x800000	/* Proc has continued from a stopped state. */
 
 #define	P_BITS \
     ("\20\01ADVLOCK\02CTTY\03INMEM\04NOCLDSTOP\05PPWAIT\06PROFIL\07SELECT" \
      "\010SINTR\011SUGID\012SYSTEM\013TIMEOUT\014TRACED\015WAITED\016WEXIT" \
      "\017EXEC\020PWEUPC\021FSTRACE\022SSTEP\023SUGIDEXEC\024NOCLDWAIT" \
-     "\025NOZOMBIE\026INEXEC\027SYSTRACE")
+     "\025NOZOMBIE\026INEXEC\027SYSTRACE\030CONTINUED")
 
 /* Macro to compute the exit signal to be delivered. */
 #define P_EXITSIG(p) \

sys/sys/wait.h

@@ -1,4 +1,4 @@
-/*	$OpenBSD: wait.h,v 1.10 2003/06/02 23:28:22 millert Exp $	*/
+/*	$OpenBSD: wait.h,v 1.11 2003/08/03 19:25:49 millert Exp $	*/
 /*	$NetBSD: wait.h,v 1.11 1996/04/09 20:55:51 cgd Exp $	*/
 
 /*
@@ -53,12 +53,14 @@
 
 #define	_WSTATUS(x)	(_W_INT(x) & 0177)
 #define	_WSTOPPED	0177		/* _WSTATUS if process is stopped */
-#define WIFSTOPPED(x)	(_WSTATUS(x) == _WSTOPPED)
+#define	_WCONTINUED	0177777		/* process has continued */
+#define WIFSTOPPED(x)	((_W_INT(x) & 0xff) == _WSTOPPED)
 #define WSTOPSIG(x)	((_W_INT(x) >> 8) & 0xff)
 #define WIFSIGNALED(x)	(_WSTATUS(x) != _WSTOPPED && _WSTATUS(x) != 0)
 #define WTERMSIG(x)	(_WSTATUS(x))
 #define WIFEXITED(x)	(_WSTATUS(x) == 0)
 #define WEXITSTATUS(x)	((_W_INT(x) >> 8) & 0xff)
+#define WIFCONTINUED(x)	((_W_INT(x) & _WCONTINUED) == _WCONTINUED)
 #ifndef _POSIX_SOURCE
 #define WCOREDUMP(x)	(_W_INT(x) & WCOREFLAG)
 
@@ -80,6 +82,7 @@
 #ifndef _POSIX_SOURCE
 #define	WALTSIG		4	/* wait for child with alternate exit signal */
 #endif
+#define	WCONTINUED	8	/* report a job control continued process */
 
 #ifndef _POSIX_SOURCE
 /* POSIX extensions and 4.2/4.3 compatibility: */