From 7c709434eccd461a3f3c522df6224adf4e50a8da Mon Sep 17 00:00:00 2001
From: rsc <devnull@localhost>
Date: Fri, 18 Mar 2005 19:30:22 +0000
Subject: new files

---
 src/cmd/netfiles/wait.c | 120 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 120 insertions(+)
 create mode 100644 src/cmd/netfiles/wait.c

(limited to 'src/cmd/netfiles/wait.c')

diff --git a/src/cmd/netfiles/wait.c b/src/cmd/netfiles/wait.c
new file mode 100644
index 00000000..6f31a29b
--- /dev/null
+++ b/src/cmd/netfiles/wait.c
@@ -0,0 +1,120 @@
+#include <u.h>
+#include <libc.h>
+#include <thread.h>
+#include <9pclient.h>
+#include "acme.h"
+
+extern int debug;
+
+#define dprint if(debug)print
+
+typedef struct Waitreq Waitreq;
+struct Waitreq
+{
+	int pid;
+	Channel *c;
+};
+
+/*
+ * watch the exiting children
+ */
+Channel *twaitchan;	/* chan(Waitreq) */
+void
+waitthread(void *v)
+{
+	Alt a[3];
+	Waitmsg *w, **wq;
+	Waitreq *rq, r;
+	int i, nrq, nwq;
+
+	threadsetname("waitthread");
+	a[0].c = threadwaitchan();
+	a[0].v = &w;
+	a[0].op = CHANRCV;
+	a[1].c = twaitchan;
+	a[1].v = &r;
+	a[1].op = CHANRCV;
+	a[2].op = CHANEND;
+
+	nrq = 0;
+	nwq = 0;
+	rq = nil;
+	wq = nil;
+	dprint("wait: start\n");
+	for(;;){
+	cont2:;
+		dprint("wait: alt\n");
+		switch(alt(a)){
+		case 0:
+			dprint("wait: pid %d exited\n", w->pid);
+			for(i=0; i<nrq; i++){
+				if(rq[i].pid == w->pid){
+					dprint("wait: match with rq chan %p\n", rq[i].c);
+					sendp(rq[i].c, w);
+					rq[i] = rq[--nrq];
+					goto cont2;
+				}
+			}
+			if(i == nrq){
+				dprint("wait: queueing waitmsg\n");
+				wq = erealloc(wq, (nwq+1)*sizeof(wq[0]));
+				wq[nwq++] = w;
+			}
+			break;
+		
+		case 1:
+			dprint("wait: req for pid %d chan %p\n", r.pid, r.c);
+			for(i=0; i<nwq; i++){
+				if(w->pid == r.pid){
+					dprint("wait: match with waitmsg\n");
+					sendp(r.c, w);
+					wq[i] = wq[--nwq];
+					goto cont2;
+				}
+			}
+			if(i == nwq){
+				dprint("wait: queueing req\n");
+				rq = erealloc(rq, (nrq+1)*sizeof(rq[0]));
+				rq[nrq] = r;
+				dprint("wait: queueing req pid %d chan %p\n", rq[nrq].pid, rq[nrq].c);
+				nrq++;
+			}
+			break;
+		}
+	}
+}
+
+Waitmsg*
+twaitfor(int pid)
+{
+	Waitreq r;
+	Waitmsg *w;
+	
+	r.pid = pid;
+	r.c = chancreate(sizeof(Waitmsg*), 1);
+	send(twaitchan, &r);
+	w = recvp(r.c);
+	chanfree(r.c);
+	return w;
+}
+
+int
+twait(int pid)
+{
+	int x;
+	Waitmsg *w;
+	
+	w = twaitfor(pid);
+	x = w->msg[0] != 0 ? -1 : 0;
+	free(w);
+	return x;
+}
+
+void
+twaitinit(void)
+{
+	threadwaitchan();	/* allocate it before returning */
+	twaitchan = chancreate(sizeof(Waitreq), 10);
+	threadcreate(waitthread, nil, 128*1024);
+}
+
-- 
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