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@

diff --git a/sbin/dmesg/dmesg.8 b/sbin/dmesg/dmesg.8
index a85c8b3..2ece4d3 100644 (file)
--- a/sbin/dmesg/dmesg.8
+++ b/sbin/dmesg/dmesg.8
@@ -1,4 +1,4 @@
-.\"    $OpenBSD: dmesg.8,v 1.14 2013/08/14 06:32:35 jmc Exp $
+.\"    $OpenBSD: dmesg.8,v 1.15 2015/01/13 10:07:58 mpf Exp $
 .\"    $NetBSD: dmesg.8,v 1.9 1995/03/18 14:54:47 cgd Exp $
 .\"
 .\" Copyright (c) 1980, 1991, 1993
@@ -30,7 +30,7 @@
 .\"
 .\"     @(#)dmesg.8    8.1 (Berkeley) 6/5/93
 .\"
-.Dd $Mdocdate: August 14 2013 $
+.Dd $Mdocdate: January 13 2015 $
 .Dt DMESG 8
 .Os
 .Sh NAME
@@ -38,6 +38,7 @@
 .Nd display the system message buffer
 .Sh SYNOPSIS
 .Nm dmesg
+.Op Fl s
 .Op Fl M Ar core
 .Op Fl N Ar system
 .Sh DESCRIPTION
@@ -57,6 +58,12 @@ Extract the name list from the specified
 .Ar system
 instead of the default
 .Pa /bsd .
+.It Fl s
+Display the contents of the console message buffer instead.
+This can be used to review
+.Xr rc 8
+system startup messages.
+This option is limited to the superuser.
 .El
 .Sh FILES
 .Bl -tag -width /var/run/dmesg.boot -compact

diff --git a/sbin/dmesg/dmesg.c b/sbin/dmesg/dmesg.c
index 35fe2d8..a83c9fe 100644 (file)
--- a/sbin/dmesg/dmesg.c
+++ b/sbin/dmesg/dmesg.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: dmesg.c,v 1.23 2014/04/22 20:43:12 tedu Exp $ */
+/*     $OpenBSD: dmesg.c,v 1.24 2015/01/13 10:07:58 mpf Exp $  */
 /*     $NetBSD: dmesg.c,v 1.8 1995/03/18 14:54:49 cgd Exp $    */
 
 /*-
@@ -66,11 +66,15 @@ main(int argc, char *argv[])
        char *p;
        struct msgbuf cur;
        char *memf, *nlistf, *bufdata = NULL;
+       int startupmsgs = 0;
        char buf[5];
 
        memf = nlistf = NULL;
-       while ((ch = getopt(argc, argv, "M:N:")) != -1)
+       while ((ch = getopt(argc, argv, "sM:N:")) != -1)
                switch(ch) {
+               case 's':
+                       startupmsgs = 1;
+                       break;
                case 'M':
                        memf = optarg;
                        break;
@@ -89,7 +93,7 @@ main(int argc, char *argv[])
                size_t len;
 
                mib[0] = CTL_KERN;
-               mib[1] = KERN_MSGBUFSIZE;
+               mib[1] = startupmsgs ? KERN_CONSBUFSIZE : KERN_MSGBUFSIZE;
                len = sizeof(msgbufsize);
                if (sysctl(mib, 2, &msgbufsize, &len, NULL, 0))
                        err(1, "sysctl: KERN_MSGBUFSIZE");
@@ -99,7 +103,7 @@ main(int argc, char *argv[])
                if (bufdata == NULL)
                        errx(1, "couldn't allocate space for buffer data");
 
-               mib[1] = KERN_MSGBUF;
+               mib[1] = startupmsgs ? KERN_CONSBUF : KERN_MSGBUF;
                len = msgbufsize;
                if (sysctl(mib, 2, bufdata, &len, NULL, 0))
                        err(1, "sysctl: KERN_MSGBUF");
@@ -179,6 +183,6 @@ usage(void)
 {
        extern char *__progname;
 
-       fprintf(stderr, "usage: %s [-M core] [-N system]\n", __progname);
+       fprintf(stderr, "usage: %s [-s] [-M core] [-N system]\n", __progname);
        exit(1);
 }

diff --git a/sys/kern/kern_sysctl.c b/sys/kern/kern_sysctl.c
index a3f807d..04e08d2 100644 (file)
--- 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 ec1e2eb..6720d5e 100644 (file)
--- 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 899fcb5..06f2cc6 100644 (file)
--- 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 c9b8cc6..419f6e6 100644 (file)
--- 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 bce761e..8ca1511 100644 (file)
--- 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 58d53eb..a8004cd 100644 (file)
--- 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 }, \