Allow waiting for all children at once

From: Pavel Machek (pavel@suse.cz)
Date: Sun Feb 20 2000 - 05:39:46 EST

Hi!

It is currently impossible to wait for all children at same time. This
is esential for strace tracing mix of threads and processes.

[patch is against 42, but I checked it applies to 46]
                                                                Pavel

--- linux-2.3.42/kernel/exit.c.orig Sat Feb 5 02:08:19 2000
+++ linux-2.3.42/kernel/exit.c Sat Feb 5 02:09:32 2000
@@ -445,7 +445,7 @@
         DECLARE_WAITQUEUE(wait, current);
         struct task_struct *p;
 
- if (options & ~(WNOHANG|WUNTRACED|__WCLONE))
+ if (options & ~(WNOHANG|WUNTRACED|__WCLONE|__WALL))
                 return -EINVAL;
 
         add_wait_queue(&current->wait_chldexit,&wait);
@@ -464,8 +464,13 @@
                         if (p->pgrp != -pid)
                                 continue;
                 }
- /* wait for cloned processes iff the __WCLONE flag is set */
- if ((p->exit_signal != SIGCHLD) ^ ((options & __WCLONE) != 0))
+ /* Wait for all children (clone and not) if __WALL is set;
+ * otherwise, wait for clone children *only* if __WCLONE is
+ * set; otherwise, wait for non-clone children *only*. (Note:
+ * A "clone" child here is one that reports to its parent
+ * using a signal other than SIGCHLD.) */
+ if (((p->exit_signal != SIGCHLD) ^ ((options & __WCLONE) != 0))
+ && !(options & __WALL))
                         continue;
                 flag = 1;
                 switch (p->state) {
--- linux-2.3.42/include/linux/wait.h.orig Mon Jan 10 20:29:12 2000
+++ linux-2.3.42/include/linux/wait.h Sat Feb 5 02:09:32 2000
@@ -4,6 +4,7 @@
 #define WNOHANG 0x00000001
 #define WUNTRACED 0x00000002
 
+#define __WALL 0x40000000
 #define __WCLONE 0x80000000
 
 #ifdef __KERNEL__ 

-- 
I'm pavel@ucw.cz. "In my country we have almost anarchy and I don't care."
Panos Katsaloulis describing me w.r.t. patents me at discuss@linmodems.org

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