From 90fbbe3585c13da7eb2984a317959279d753af59 Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Mon, 13 May 1991 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1991-05-13

---
 gnot/trap.c    |  4 +--
 port/alarm.c   | 67 ++++++++++++++++++++++++++++++++++++++++++++++++++
 port/portdat.h | 10 ++++++++
 port/portfns.h |  1 +
 port/proc.c    |  1 +
 port/sysproc.c |  5 ++++
 power/trap.c   |  4 +--
 ss/trap.c      |  4 +--
 8 files changed, 90 insertions(+), 6 deletions(-)

diff --git a/gnot/trap.c b/gnot/trap.c
index d6074f40aec15f0767feb4bf9eeeae1801cacc5a..2ecf45c287ad7e5788a98a303f65a2f8320fe69b 100644
--- a/gnot/trap.c
+++ b/gnot/trap.c
@@ -211,7 +211,7 @@ typedef long Syscall(ulong*);
 Syscall	sysr1, sysfork, sysexec, sysgetpid, syssleep, sysexits, sysdeath, syswait;
 Syscall	sysopen, sysclose, sysread, syswrite, sysseek, syserrstr, sysaccess, sysstat, sysfstat;
 Syscall sysdup, syschdir, sysforkpgrp, sysbind, sysmount, syspipe, syscreate;
-Syscall	sysbrk_, sysremove, syswstat, sysfwstat, sysnotify, sysnoted;
+Syscall	sysbrk_, sysremove, syswstat, sysfwstat, sysnotify, sysnoted, sysalarm;
 
 Syscall *systab[]={
 	sysr1,
@@ -220,7 +220,7 @@ Syscall *systab[]={
 	syschdir,
 	sysclose,
 	sysdup,
-	sysdeath,
+	sysalarm,
 	sysexec,
 	sysexits,
 	sysfork,
diff --git a/port/alarm.c b/port/alarm.c
index bc3880af9c2f119142f9a022b5ea9173d8ec2413..6bc66da1b70126bf4c531412ad42236676a58f74 100644
--- a/port/alarm.c
+++ b/port/alarm.c
@@ -6,6 +6,7 @@
 #include	"io.h"
 
 Alarm	*alarmtab;
+Alarms	alarms;
 
 Alarm*
 alarm(int ms, void (*f)(Alarm*), void *arg)
@@ -82,6 +83,8 @@ checkalarms(void)
 	Alarm *a;
 	void (*f)(void*);
 	Alarm *alist[NA];
+	ulong now;
+	Proc *rp;
 
 	if(canlock(&m->alarmlock)){
 		a = m->alarm;
@@ -105,4 +108,68 @@ checkalarms(void)
 		} else
 			unlock(&m->alarmlock);
 	}
+
+	if(m == MACHP(0) && canqlock(&alarms)) {
+		now = MACHP(0)->ticks;
+		while((rp = alarms.head) && rp->alarm <= now) {
+			if(rp->alarm != 0L) {
+				if(canlock(&rp->debug)) {
+					postnote(rp, 0, "alarm", NUser);
+					unlock(&rp->debug);
+					rp->alarm = 0L;
+				}
+				else
+					break;
+			}
+			alarms.head = rp->palarm;
+		}
+	}
+	qunlock(&alarms);
+}
+
+ulong
+procalarm(ulong time)
+{
+	Proc **l, *f;
+	ulong when, old;
+
+	when = MS2TK(time);
+	old = u->p->alarm - MACHP(0)->ticks;
+	if(when == 0) {
+		u->p->alarm = 0;
+		return TK2MS(old);
+	}
+	else
+		when += MACHP(0)->ticks;
+
+	qlock(&alarms);
+	l = &alarms.head;
+	for(f = *l; f; f = f->palarm) {
+		if(u->p == f) {
+			*l = f->palarm;
+			break;
+		}
+		l = &f->palarm;
+	}
+
+	u->p->palarm = 0;
+	if(alarms.head) {
+		l = &alarms.head;
+		for(f = *l; f; f = f->palarm) {
+			if(f->alarm > when) {
+				u->p->palarm = f;
+				*l = u->p;
+				goto done;
+			}
+			l = &f->palarm;
+		}
+		*l = u->p;
+	}
+	else
+		alarms.head = u->p;
+done:
+	u->p->alarm = when;
+	qunlock(&alarms);
+
+	return TK2MS(old);			
 }
diff --git a/port/portdat.h b/port/portdat.h
index 5778c33970f783d9eb909c1baf6dacef310e0d04..17fd686c5b8f6b17402c1d469691ab9c7779a79f 100644
--- a/port/portdat.h
+++ b/port/portdat.h
@@ -1,4 +1,5 @@
 typedef struct Alarm	Alarm;
+typedef struct Alarms	Alarms;
 typedef struct Block	Block;
 typedef struct Blist	Blist;
 typedef struct Chan	Chan;
@@ -62,6 +63,12 @@ struct Alarm
 	void	*arg;
 };
 
+struct Alarms
+{
+	QLock;
+	Proc	*head;
+};
+
 /* Block.flags */
 #define S_DELIM 0x80
 #define S_CLASS 0x07
@@ -347,6 +354,9 @@ struct Proc
 	int	wokeup;			/* whether sleep was interrupted */
 	ulong	pc;			/* DEBUG only */
 	int	kp;			/* true if a kernel process */
+	Proc	*palarm;		/* Next alarm time */
+	ulong	alarm;			/* Time of call */
+
 	/*
 	 *  machine specific MMU goo
 	 */
diff --git a/port/portfns.h b/port/portfns.h
index 4fad3fba9b5391f3a2d2962fbfbcc584053a5b99..bda32d2845db61942f03fe0884d60a26929dc7fa 100644
--- a/port/portfns.h
+++ b/port/portfns.h
@@ -107,6 +107,7 @@ Pgrp*	pgrptab(int);
 int	postnote(Proc*, int, char*, int);
 int	pprint(char*, ...);
 void	printslave(void);
+ulong 	procalarm(ulong);
 void	procinit0(void);
 Proc*	proctab(int);
 Block*	pullup(Block *, int);
diff --git a/port/proc.c b/port/proc.c
index d2f26336c38f21b9f1d482aafe94589fb27eb7f2..104f40b8cba128b8a4651094899c6e9170d999a1 100644
--- a/port/proc.c
+++ b/port/proc.c
@@ -441,6 +441,7 @@ pexit(char *s, int freemem)
 	else
 		msg[0] = 0;
 	c = u->p;
+	c->alarm = 0;
 	mypid = c->pid;
 	if(freemem){
 		freesegs(-1);
diff --git a/port/sysproc.c b/port/sysproc.c
index 56cea0a72dd68599dc2a1b232102bab51bea451e..d9bf1f5c479231df4cb79afe71771918c0f70442 100644
--- a/port/sysproc.c
+++ b/port/sysproc.c
@@ -407,6 +407,11 @@ syssleep(ulong *arg)
 	return 0;
 }
 
+long
+sysalarm(ulong *arg)
+{
+	return procalarm(arg[0]);		
+}
 
 long
 sysexits(ulong *arg)
diff --git a/power/trap.c b/power/trap.c
index 15a6b5e6ac10c434175cfcda24baefdacde2a432..009b5a4db4951daacd856769eab9f432a015631d 100644
--- a/power/trap.c
+++ b/power/trap.c
@@ -437,7 +437,7 @@ Syscall sysbind, sysbrk_, syschdir, sysclose, syscreate, sysdeath;
 Syscall	sysdup, syserrstr, sysexec, sysexits, sysfork, sysforkpgrp;
 Syscall	sysfstat, sysfwstat, sysgetpid, sysmount, sysnoted;
 Syscall	sysnotify, sysopen, syspipe, sysr1, sysread, sysremove, sysseek;
-Syscall syssleep, sysstat, syswait, syswrite, syswstat;
+Syscall syssleep, sysstat, syswait, syswrite, syswstat, sysalarm;
 
 Syscall *systab[]={
 	[SYSR1]		sysr1,
@@ -446,7 +446,7 @@ Syscall *systab[]={
 	[CHDIR]		syschdir,
 	[CLOSE]		sysclose,
 	[DUP]		sysdup,
-	[___ERRSTR___]	sysdeath,
+	[ALARM]		sysalarm,
 	[EXEC]		sysexec,
 	[EXITS]		sysexits,
 	[FORK]		sysfork,
diff --git a/ss/trap.c b/ss/trap.c
index 525b5e76398780b7ea347016a67671d7e7405cc1..7f8fb2a4a186c95f6af5e17e2706421e9f8f2517 100644
--- a/ss/trap.c
+++ b/ss/trap.c
@@ -270,7 +270,7 @@ typedef long Syscall(ulong*);
 Syscall	sysr1, sysfork, sysexec, sysgetpid, syssleep, sysexits, sysdeath, syswait;
 Syscall	sysopen, sysclose, sysread, syswrite, sysseek, syserrstr, sysaccess, sysstat, sysfstat;
 Syscall sysdup, syschdir, sysforkpgrp, sysbind, sysmount, syspipe, syscreate;
-Syscall	sysbrk_, sysremove, syswstat, sysfwstat, sysnotify, sysnoted;
+Syscall	sysbrk_, sysremove, syswstat, sysfwstat, sysnotify, sysnoted, sysalarm;
 
 Syscall *systab[]={
 	sysr1,
@@ -279,7 +279,7 @@ Syscall *systab[]={
 	syschdir,
 	sysclose,
 	sysdup,
-	sysdeath,
+	sysalarm,
 	sysexec,
 	sysexits,
 	sysfork,