Various additions and fixes.

src/lib9/_p9proc.c

@@ -0,0 +1,73 @@
+#include <u.h>
+#include <libc.h>
+#include "9proc.h"
+
+static Lock uproclock;
+static Uproc *phash[PIDHASH];
+
+Uproc*
+_p9uproc(void)
+{
+	/* for now, assume getpid is fast or cached */
+	int pid;
+	Uproc *up;
+
+	pid = getpid();
+again:
+if(0)print("find %d\n", pid);
+	lock(&uproclock);
+	for(up=phash[pid%PIDHASH]; up; up=up->next){
+		if(up->pid == pid){
+if(0)print("found %d\n", pid);
+			unlock(&uproclock);
+			return up;
+		}
+	}
+
+	up = mallocz(sizeof(Uproc), 1);
+	if(up == nil){
+if(0)print("again %d\n", pid);
+		unlock(&uproclock);
+		sleep(1000);
+		goto again;
+	}
+
+againpipe:
+	if(pipe(up->pipe) < 0){
+if(0)print("againpipe %d\n", pid);
+		sleep(1000);
+		goto againpipe;
+	}
+
+	up->pid = pid;
+	up->next = phash[pid%PIDHASH];
+	phash[pid%PIDHASH] = up;
+if(0)print("link %d\n", pid);
+	unlock(&uproclock);
+	return up;
+}
+
+void
+_p9uprocdie(void)
+{
+	Uproc **l, *up;
+	int pid;
+
+	pid = getpid();
+if(0)print("die %d\n", pid);
+	lock(&uproclock);
+	for(l=&phash[pid%33]; *l; l=&(*l)->next){
+		if((*l)->pid == pid){
+			up = *l;
+			*l = up->next;
+if(0)print("died %d\n", pid);
+			unlock(&uproclock);
+			close(up->pipe[0]);
+			close(up->pipe[1]);
+			free(up);
+			return;
+		}
+	}
+if(0)print("not started %d\n", pid);
+	unlock(&uproclock);
+}