From 3e57fb8c8d043c7880e36dae76e5919d3bd85b74 Mon Sep 17 00:00:00 2001
From: Avery Pennarun <apenwarr@gmail.com>
Date: Wed, 11 Apr 2012 20:53:25 -0400
Subject: [PATCH] Change syslogd headers to match what /dev/kmsg needs.

In other words, drop the extra timestamp and hostname and whitespace, and
insert <7> to tell the kernel it's a KERN_DEBUG-level message.
---
 syslogd.c |   51 +++++++++++++++++++++++++++++++++++++--------------
 1 files changed, 37 insertions(+), 14 deletions(-)

diff --git a/syslogd.c b/syslogd.c
index 4b1ad2e..402f8e6 100644
--- a/syslogd.c
+++ b/syslogd.c
@@ -714,10 +714,11 @@ int	repeatinterval[] = { 30, 60 };	/* # of secs before flush */
 #define F_FORW_SUSP	7		/* suspended host forwarding */
 #define F_FORW_UNKN	8		/* unknown host forwarding */
 #define F_PIPE		9		/* named pipe */
+#define F_KMSG		10		/* /dev/kmsg device */
 char	*TypeNames[] = {
 	"UNUSED",	"FILE",		"TTY",		"CONSOLE",
 	"FORW",		"USERS",	"WALL",		"FORW(SUSPENDED)",
-	"FORW(UNKNOWN)", "PIPE"
+	"FORW(UNKNOWN)", "PIPE", "KMSG"
 };
 
 struct	filed *Files = (struct filed *) 0;
@@ -1758,18 +1759,34 @@ void fprintlog(f, from, flags, msg)
 
 	dprintf("Called fprintlog, ");
 
-	v->iov_base = f->f_lasttime;
-	v->iov_len = 15;
-	v++;
-	v->iov_base = " ";
-	v->iov_len = 1;
-	v++;
-	v->iov_base = f->f_prevhost;
-	v->iov_len = strlen(v->iov_base);
-	v++;
-	v->iov_base = " ";
-	v->iov_len = 1;
-	v++;
+	if (f->f_type == F_KMSG) {
+		v->iov_base = "<7>";
+		v->iov_len = 3;
+		v++;
+		v->iov_base = "";
+		v->iov_len = 0;
+		v++;
+		v->iov_base = "";
+		v->iov_len = 0;
+		v++;
+		v->iov_base = "";
+		v->iov_len = 0;
+		v++;
+	} else {
+		v->iov_base = f->f_lasttime;
+		v->iov_len = 15;
+		v++;
+		v->iov_base = " ";
+		v->iov_len = 1;
+		v++;
+		v->iov_base = f->f_prevhost;
+		v->iov_len = strlen(v->iov_base);
+		v++;
+		v->iov_base = " ";
+		v->iov_len = 1;
+		v++;
+	}
+
 	if (msg) {
 		v->iov_base = msg;
 		v->iov_len = strlen(msg);
@@ -1891,6 +1908,7 @@ void fprintlog(f, from, flags, msg)
 	case F_TTY:
 	case F_FILE:
 	case F_PIPE:
+	case F_KMSG:
 		f->f_time = now;
 		dprintf(" %s\n", f->f_un.f_fname);
 		if (f->f_type == F_TTY || f->f_type == F_CONSOLE) {
@@ -2332,6 +2350,7 @@ void init()
 				case F_PIPE:
 				case F_TTY:
 				case F_CONSOLE:
+				case F_KMSG:
 					(void) close(f->f_file);
 				break;
 			}
@@ -2483,6 +2502,7 @@ void init()
 				case F_PIPE:
 				case F_TTY:
 				case F_CONSOLE:
+				case F_KMSG:
 					printf("%s", f->f_un.f_fname);
 					if (f->f_file == -1)
 						printf(" (unused)");
@@ -2745,7 +2765,10 @@ void cfline(line, f)
 		} else {
 			f->f_file = open(p, O_WRONLY|O_APPEND|O_CREAT|O_NONBLOCK|O_NOCTTY,
 					 0644);
-			f->f_type = F_FILE;
+			if (strcmp(p, "/dev/kmsg") == 0)
+				f->f_type = F_KMSG;
+			else
+				f->f_type = F_FILE;
 		}
 		        
 	  	if ( f->f_file < 0 ){
-- 
1.7.9