Add dmesg -s support, to view the output of rc(8) system startup messages.

Help and feedback by Theo and Miod.
OK deraadt@, manpage-ok jmc@

6 files changed, 55 insertions, 21 deletions

diff --git a/sys/kern/kern_sysctl.c b/sys/kern/kern_sysctl.c
index a3f807dc5be..04e08d21fbe 100644
--- a/sys/kern/kern_sysctl.c
+++ b/sys/kern/kern_sysctl.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_sysctl.c,v 1.277 2014/12/12 07:45:46 tedu Exp $	*/
+/*	$OpenBSD: kern_sysctl.c,v 1.278 2015/01/13 10:07:58 mpf Exp $	*/
 /*	$NetBSD: kern_sysctl.c,v 1.17 1996/05/20 17:49:05 mrg Exp $	*/
 
 /*-
@@ -444,19 +444,30 @@ kern_sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp,
 		return (sysctl_rdint(oldp, oldlenp, newp, 0));
 #endif
 	case KERN_MSGBUFSIZE:
+	case KERN_CONSBUFSIZE: {
+		struct msgbuf *mp;
+		mp = (name[0] == KERN_MSGBUFSIZE) ? msgbufp : consbufp;
 		/*
 		 * deal with cases where the message buffer has
 		 * become corrupted.
 		 */
-		if (!msgbufp || msgbufp->msg_magic != MSG_MAGIC)
+		if (!mp || mp->msg_magic != MSG_MAGIC)
 			return (ENXIO);
-		return (sysctl_rdint(oldp, oldlenp, newp, msgbufp->msg_bufs));
-	case KERN_MSGBUF:
+		return (sysctl_rdint(oldp, oldlenp, newp, mp->msg_bufs));
+	}
+	case KERN_CONSBUF:
+		if ((error = suser(p, 0)))
+			return (error);
+		/* FALLTHROUGH */
+	case KERN_MSGBUF: {
+		struct msgbuf *mp;
+		mp = (name[0] == KERN_MSGBUF) ? msgbufp : consbufp;
 		/* see note above */
-		if (!msgbufp || msgbufp->msg_magic != MSG_MAGIC)
+		if (!mp || mp->msg_magic != MSG_MAGIC)
 			return (ENXIO);
-		return (sysctl_rdstruct(oldp, oldlenp, newp, msgbufp,
-		    msgbufp->msg_bufs + offsetof(struct msgbuf, msg_bufc)));
+		return (sysctl_rdstruct(oldp, oldlenp, newp, mp,
+		    mp->msg_bufs + offsetof(struct msgbuf, msg_bufc)));
+	}
 	case KERN_MALLOCSTATS:
 		return (sysctl_malloc(name + 1, namelen - 1, oldp, oldlenp,
 		    newp, newlen, p));
diff --git a/sys/kern/subr_log.c b/sys/kern/subr_log.c
index ec1e2ebb850..6720d5ede34 100644
--- a/sys/kern/subr_log.c
+++ b/sys/kern/subr_log.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: subr_log.c,v 1.25 2014/12/13 21:05:33 doug Exp $	*/
+/*	$OpenBSD: subr_log.c,v 1.26 2015/01/13 10:07:58 mpf Exp $	*/
 /*	$NetBSD: subr_log.c,v 1.11 1996/03/30 22:24:44 christos Exp $	*/
 
 /*
@@ -74,8 +74,8 @@ struct logsoftc {
 
 int	log_open;			/* also used in log() */
 int	msgbufmapped;			/* is the message buffer mapped */
-int	msgbufenabled;			/* is logging to the buffer enabled */
 struct	msgbuf *msgbufp;		/* the mapped buffer, itself. */
+struct	msgbuf *consbufp;		/* console message buffer. */
 struct file *syslogf;
 
 void filt_logrdetach(struct knote *kn);
@@ -113,17 +113,23 @@ initmsgbuf(caddr_t buf, size_t bufsize)
 	
 	/* Always start new buffer data on a new line. */
 	if (mbp->msg_bufx > 0 && mbp->msg_bufc[mbp->msg_bufx - 1] != '\n')
-		msgbuf_putchar('\n');
+		msgbuf_putchar(msgbufp, '\n');
 
 	/* mark it as ready for use. */
-	msgbufmapped = msgbufenabled = 1;
+	msgbufmapped = 1;
+
+	/* Set up a buffer to collect /dev/console output */
+	consbufp = malloc(CONSBUFSIZE, M_TEMP, M_NOWAIT|M_ZERO);
+	if (consbufp) {
+		new_bufs = CONSBUFSIZE - offsetof(struct msgbuf, msg_bufc);
+		consbufp->msg_magic = MSG_MAGIC;
+		consbufp->msg_bufs = new_bufs;
+	}
 }
 
 void
-msgbuf_putchar(const char c) 
+msgbuf_putchar(struct msgbuf *mbp, const char c) 
 {
-	struct msgbuf *mbp = msgbufp;
-
 	if (mbp->msg_magic != MSG_MAGIC)
 		/* Nothing we can do */
 		return;
diff --git a/sys/kern/subr_prf.c b/sys/kern/subr_prf.c
index 899fcb529d5..06f2cc60161 100644
--- a/sys/kern/subr_prf.c
+++ b/sys/kern/subr_prf.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: subr_prf.c,v 1.83 2014/07/13 23:49:40 uebayasi Exp $	*/
+/*	$OpenBSD: subr_prf.c,v 1.84 2015/01/13 10:07:58 mpf Exp $	*/
 /*	$NetBSD: subr_prf.c,v 1.45 1997/10/24 18:14:25 chuck Exp $	*/
 
 /*-
@@ -349,7 +349,7 @@ kputchar(int c, int flags, struct tty *tp)
 		constty = NULL;
 	if ((flags & TOLOG) &&
 	    c != '\0' && c != '\r' && c != 0177 && msgbufmapped)
-		msgbuf_putchar(c);
+		msgbuf_putchar(msgbufp, c);
 	if ((flags & TOCONS) && (constty == NULL || ddb_active) && c != '\0')
 		(*v_putc)(c);
 #ifdef DDB
diff --git a/sys/kern/tty.c b/sys/kern/tty.c
index c9b8cc6adbe..419f6e65d90 100644
--- a/sys/kern/tty.c
+++ b/sys/kern/tty.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: tty.c,v 1.119 2014/12/17 19:42:15 tedu Exp $	*/
+/*	$OpenBSD: tty.c,v 1.120 2015/01/13 10:07:58 mpf Exp $	*/
 /*	$NetBSD: tty.c,v 1.68.4.2 1996/06/06 16:04:52 thorpej Exp $	*/
 
 /*-
@@ -52,6 +52,7 @@
 #include <sys/lock.h>
 #include <sys/syslog.h>
 #include <sys/malloc.h>
+#include <sys/msgbuf.h>
 #include <sys/signalvar.h>
 #include <sys/resourcevar.h>
 #include <sys/sysctl.h>
@@ -63,6 +64,7 @@
 
 #include <uvm/uvm_extern.h>
 
+#include <dev/cons.h>
 #include <dev/rndvar.h>
 
 #include "pty.h"
@@ -1786,6 +1788,17 @@ loop:
 			}
 			if (cc > obufcc)
 				obufcc = cc;
+
+			/* duplicate /dev/console output into console buffer */
+			if (consbufp && cn_tab &&
+			    cn_tab->cn_dev == tp->t_dev && tp->t_gen == 0) {
+				int i;
+				for (i = 0; i < cc; i++) {
+					char c = cp[i];
+					if (c != '\0' && c != '\r' && c != 0177)
+						msgbuf_putchar(consbufp, c);
+				}
+			}
 		}
 		/*
 		 * If nothing fancy need be done, grab those characters we
diff --git a/sys/sys/msgbuf.h b/sys/sys/msgbuf.h
index bce761e3036..8ca1511b061 100644
--- a/sys/sys/msgbuf.h
+++ b/sys/sys/msgbuf.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: msgbuf.h,v 1.8 2005/04/14 21:58:50 krw Exp $	*/
+/*	$OpenBSD: msgbuf.h,v 1.9 2015/01/13 10:07:58 mpf Exp $	*/
 /*	$NetBSD: msgbuf.h,v 1.8 1995/03/26 20:24:27 jtc Exp $	*/
 
 /*
@@ -42,8 +42,10 @@ struct	msgbuf {
 	char	msg_bufc[1];		/* buffer */
 };
 #ifdef _KERNEL
+#define CONSBUFSIZE	(16 * 1024)	/* console message buffer size */
 extern struct msgbuf *msgbufp;
+extern struct msgbuf *consbufp;
 
 void	initmsgbuf(caddr_t buf, size_t bufsize);
-void	msgbuf_putchar(const char c);
+void	msgbuf_putchar(struct msgbuf *, const char c);
 #endif
diff --git a/sys/sys/sysctl.h b/sys/sys/sysctl.h
index 58d53eb1f8c..a8004cdedea 100644
--- a/sys/sys/sysctl.h
+++ b/sys/sys/sysctl.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: sysctl.h,v 1.153 2014/12/12 07:45:46 tedu Exp $	*/
+/*	$OpenBSD: sysctl.h,v 1.154 2015/01/13 10:07:58 mpf Exp $	*/
 /*	$NetBSD: sysctl.h,v 1.16 1996/04/09 20:55:36 cgd Exp $	*/
 
 /*
@@ -182,7 +182,9 @@ struct ctlname {
 #define	KERN_PROC_NOBROADCASTKILL 79	/* node: proc no broadcast kill */
 #define	KERN_PROC_VMMAP		80      /* node: proc vmmap */
 #define	KERN_GLOBAL_PTRACE	81	/* allow ptrace globally */
-#define	KERN_MAXID		82	/* number of valid kern ids */
+#define	KERN_CONSBUFSIZE	82	/* int: console message buffer size */
+#define	KERN_CONSBUF		83	/* console message buffer */
+#define	KERN_MAXID		84	/* number of valid kern ids */
 
 #define	CTL_KERN_NAMES { \
 	{ 0, 0 }, \