From 3451543e87c70c9de6eb445a2c08e5b62df8e698 Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Fri, 20 Jul 1990 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1990-07-20

---
 gnot/dat.h     |  2 +-
 port/devcons.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++
 port/page.c    |  1 +
 power/dat.h    |  6 ++---
 power/fns.h    |  1 +
 5 files changed, 76 insertions(+), 4 deletions(-)

diff --git a/gnot/dat.h b/gnot/dat.h
index 6d3d915d8a8772e0ddad34304b2dd95bde1e198f..487ef5c6350cfce7618d7879e4509cfc31c6ae2b 100644
--- a/gnot/dat.h
+++ b/gnot/dat.h
@@ -454,7 +454,7 @@ enum {
 	Sctlqid = Sdataqid-1,
 	Slowqid = Sctlqid,
 	Streamhi= (9*1024),	/* byte count high water mark */
-	Streambhi= 16,		/* block count high water mark */
+	Streambhi= 32,		/* block count high water mark */
 };
 
 #define	PRINTSIZE	256
diff --git a/port/devcons.c b/port/devcons.c
index 606b9ea33fd695b6217652c4b09c60d53e0b7a6b..694b3c9d7f9bad81a008affa49db3352bca38e93 100644
--- a/port/devcons.c
+++ b/port/devcons.c
@@ -290,6 +290,7 @@ enum{
 	Qdir,
 	Qcons,
 	Qcputime,
+	Qlog,
 	Qnull,
 	Qpgrpid,
 	Qpid,
@@ -301,6 +302,7 @@ enum{
 Dirtab consdir[]={
 	"cons",		Qcons,		0,	0600,
 	"cputime",	Qcputime,	72,	0600,
+	"log",		Qlog,		sizeof(SYSLOG->buf),	0600,
 	"null",		Qnull,		0,	0600,
 	"pgrpid",	Qpgrpid,	12,	0600,
 	"pid",		Qpid,		12,	0600,
@@ -496,6 +498,9 @@ consread(Chan *c, void *buf, long n)
 	case Quser:
 		return readstr(c->offset, buf, n, u->p->pgrp->user);
 
+	case Qlog:
+		return readlog(c->offset, buf, n);
+
 	case Qnull:
 		return 0;
 
@@ -588,3 +593,68 @@ consuserstr(Error *e, char *buf)
 {
 	strcpy(buf, u->p->pgrp->user);
 }
+
+/*
+ *  crash info
+ */
+void
+sysloginit(void)
+{
+	Syslog *s;
+	char *p;
+
+	s = SYSLOG;
+	if(s->magic!=SYSLOGMAGIC || s->next>=&s->buf[sizeof(s->buf)]
+	|| s->next<s->buf){
+		s->next = s->buf;
+		s->magic = SYSLOGMAGIC;
+	}
+}
+
+void
+syslog(char *p, int n)
+{
+	int i;
+	Syslog *s;
+	char *end;
+
+	s = SYSLOG;
+	end = &s->buf[sizeof(s->buf)];
+	while(n-- > 0){
+		*s->next++ = *p++;
+		if(s->next >= end)
+			s->next = s->buf;
+	}
+}
+
+long
+readlog(ulong off, char *buf, ulong n)
+{
+	Syslog *s;
+	int i;
+	char *p;
+	char *end;
+
+	s = SYSLOG;
+
+	/* past end */
+	if(off >= sizeof(s->buf))
+		return 0;
+
+	/* trim length */
+	if(off + n >= sizeof(s->buf))
+		n = sizeof(s->buf) - off;
+
+	/* point to start of area to be read */
+	end = &s->buf[sizeof(s->buf)];
+	p = s->next + off;
+	if(p > end)
+		p -= sizeof(s->buf);
+
+	for(i = 0; i < n; i++){
+		*buf++ = *p++;
+		if(p >= end)
+			p = s->buf;
+	}
+	return n;
+}
diff --git a/port/page.c b/port/page.c
index f7bf7bb6ffc7846a73dc12266b18429e92103bfb..d284ee0592394791b3f993dac68716e5c6ac318b 100644
--- a/port/page.c
+++ b/port/page.c
@@ -493,6 +493,7 @@ segaddr(Seg *s, ulong min, ulong max)
 
 	if(max < min)
 		return 0;
+if(max > 20*1024*1024) pprint("segaddr %lux\n", max);
 	if(min != s->minva)	/* can't grow down yet (stacks: fault.c) */
 		return 0;
 	max = (max+(BY2PG-1)) & ~(BY2PG-1);
diff --git a/power/dat.h b/power/dat.h
index c693ccecdcc3555346db63e4fb3312b4d3ce791e..4ded1c5c557da090fb7015fa2c24bb1416940220 100644
--- a/power/dat.h
+++ b/power/dat.h
@@ -694,11 +694,11 @@ extern	FPsave	initfp;
 /*
  *  kernel based system log, passed between crashes
  */
-#define SYSLOG		((Syslog *)(0x80001B00))
-#define SYSLOGMAGIC	0x12345678
+#define SYSLOG		((Syslog *)(0xa0001B00))
+#define SYSLOGMAGIC	0x87654321
 struct Syslog
 {
 	ulong	magic;
 	char	*next;
-	char	buf[16*1024];
+	char	buf[8*1024];
 };
diff --git a/power/fns.h b/power/fns.h
index 9f30cc64beee1670374cc406bda092be0bb5c070..4a9554429ce39ebf96d3cc6bebdbc9a18320edde 100644
--- a/power/fns.h
+++ b/power/fns.h
@@ -139,6 +139,7 @@ void	putbq(Blist*, Block*);
 int	putq(Queue*, Block*);
 void	putstrn(char*, long);
 ulong	pwait(Waitmsg*);
+int	readlog(ulong, char*, ulong);
 int	readnum(ulong, char*, ulong, ulong, int);
 void	ready(Proc*);
 void	rooterrstr(Error*, char*);