Add proc_waitid

proc_wait assumes that the caller always wants WEXITED, but waitid()
does not. The new proc_waitid RPC requires the caller to specify at
least one of WEXITED, WSTOPPED, or WCONTINUED.

* hurd/process.defs (proc_waitid): New RPC.
* hurd/process_reply.defs (proc_waitid): New RPC.
* hurd/process_request.defs (proc_waitid): New RPC.
* proc/proc.h (struct proc): Add p_continued field.
* proc/wait.c (WCONTINUED, WEXITED): Define if not already defined.
(S_proc_wait): Rename implementation to S_proc_waitid, and modify to
stop assuming WEXITED. Add support for WCONTINUED.
(S_proc_wait): Reimplement by just calling S_proc_waitid with an
additional WEXITED.
(proc_mark_stop): Clear p_continued.
(proc_mark_cont): Set p_continued, clear p_waited, wake any waiting
parent.

5 files changed, 67 insertions, 11 deletions

diff --git a/hurd/process.defs b/hurd/process.defs
index d515a46d..3b091290 100644
--- a/hurd/process.defs
+++ b/hurd/process.defs
@@ -434,3 +434,20 @@ routine proc_set_entry (
 routine proc_get_entry (
 	process: process_t;
 	out entry: vm_address_t);
+
+/* Wait for a child process to exit.  If pid is zero, it waits for any
+   child in the same pgrp as the parent.  If pid is -1, it waits for
+   any child.  Otherwise, if pid is negative, it waits for any process
+   in the specified process group.  If pid is positive, it waits for
+   the specified process.  The exit status and resource usage of the
+   process are returned in status and rusage respectively.
+   options must specify at least one of WEXITED, WSTOPPED, or WCONTINUED.  */
+routine proc_waitid (
+	process: process_t;
+	sreplyport reply_port: sreply_port_t;
+	pid: pid_t;
+	options: int;
+	out status: int;
+	out sigcode: int;
+	out rusage: rusage_t;
+	out pid_status: pid_t);
diff --git a/hurd/process_reply.defs b/hurd/process_reply.defs
index 2eefcc37..4a79024c 100644
--- a/hurd/process_reply.defs
+++ b/hurd/process_reply.defs
@@ -200,3 +200,5 @@ skip; /* proc_get_exe */
 
 skip; /* proc_set_entry */
 skip; /* proc_get_entry */
+
+skip; /* proc_waitid */
diff --git a/hurd/process_request.defs b/hurd/process_request.defs
index fc9127ab..f200bf15 100644
--- a/hurd/process_request.defs
+++ b/hurd/process_request.defs
@@ -423,3 +423,5 @@ skip; /* proc_get_exe */
 
 skip; /* proc_set_entry */
 skip; /* proc_get_entry */
+
+skip; /* proc_waitid */
diff --git a/proc/proc.h b/proc/proc.h
index 64f276d3..cafcfaff 100644
--- a/proc/proc.h
+++ b/proc/proc.h
@@ -94,6 +94,7 @@ struct proc
   unsigned int p_loginleader:1;	/* leader of login collection */
   unsigned int p_dead:1;	/* process is dead */
   unsigned int p_important:1;	/* has called proc_mark_important */
+  unsigned int p_continued:1;	/* has called proc_mark_cont */
 };
 
 typedef struct proc *pstruct_t;
diff --git a/proc/wait.c b/proc/wait.c
index 3c6c8d06..0f82240a 100644
--- a/proc/wait.c
+++ b/proc/wait.c
@@ -35,6 +35,14 @@
 #include "process_S.h"
 #include <mach/mig_errors.h>
 
+#ifndef WCONTINUED
+#define WCONTINUED 4
+#endif
+
+#ifndef WEXITED
+#define WEXITED 16
+#endif
+
 static inline void
 rusage_add (struct rusage *acc, const struct rusage *b)
 {
@@ -161,24 +169,25 @@ alert_parent (struct proc *p)
 }
 
 kern_return_t
-S_proc_wait (struct proc *p,
-	     mach_port_t reply_port,
-	     mach_msg_type_name_t reply_port_type,
-	     pid_t pid,
-	     int options,
-	     int *status,
-	     int *sigcode,
-	     struct rusage *ru,
-	     pid_t *pid_status)
+S_proc_waitid (struct proc *p,
+	       mach_port_t reply_port,
+	       mach_msg_type_name_t reply_port_type,
+	       pid_t pid,
+	       int options,
+	       int *status,
+	       int *sigcode,
+	       struct rusage *ru,
+	       pid_t *pid_status)
 {
   int cancel;
 
   int reap (struct proc *child)
     {
       if (child->p_waited
-	  || (!child->p_dead
+	  || ((!child->p_dead || !(options & WEXITED))
 	      && (!child->p_stopped
-		  || !(child->p_traced || (options & WUNTRACED)))))
+		  || !(child->p_traced || (options & WUNTRACED)))
+	      && (!child->p_continued || !(options & WCONTINUED))))
 	return 0;
       child->p_waited = 1;
       *status = child->p_status;
@@ -237,6 +246,22 @@ S_proc_wait (struct proc *p,
   goto start_over;
 }
 
+kern_return_t
+S_proc_wait (struct proc *p,
+	     mach_port_t reply_port,
+	     mach_msg_type_name_t reply_port_type,
+	     pid_t pid,
+	     int options,
+	     int *status,
+	     int *sigcode,
+	     struct rusage *ru,
+	     pid_t *pid_status)
+{
+  return S_proc_waitid(p, reply_port, reply_port_type, pid,
+      options | WEXITED,
+      status, sigcode, ru, pid_status);
+}
+
 /* Implement proc_mark_stop as described in <hurd/process.defs>. */
 kern_return_t
 S_proc_mark_stop (struct proc *p,
@@ -247,6 +272,7 @@ S_proc_mark_stop (struct proc *p,
     return EOPNOTSUPP;
 
   p->p_stopped = 1;
+  p->p_continued = 0;
   p->p_status = W_STOPCODE (signo);
   p->p_sigcode = sigcode;
   p->p_waited = 0;
@@ -294,6 +320,14 @@ S_proc_mark_cont (struct proc *p)
     return EOPNOTSUPP;
 
   p->p_stopped = 0;
+  p->p_continued = 1;
+  p->p_waited = 0;
+
+  if (p->p_parent->p_waiting)
+    {
+      pthread_cond_broadcast (&p->p_parent->p_wakeup);
+      p->p_parent->p_waiting = 0;
+    }
 
   if (!p->p_parent->p_nostopcld)
     send_signal (p->p_parent->p_msgport, SIGCHLD, CLD_CONTINUED, p->p_parent->p_task);