Backout the previous fix for the sendsyslog(2) with LOG_CONS solution.

Permanently holding /dev/console open in the kernel works only until
init(8) calls revoke(2).  After that the console device vnode cannot
be used anymore.  It still resulted in a hanging init(8) if it tried
to syslog(3) something.  With the backout also dmesg -s works again.

3 files changed, 11 insertions, 23 deletions

diff --git a/sys/kern/init_main.c b/sys/kern/init_main.c
index 87f76c07bd6..9a2afd89a8c 100644
--- a/sys/kern/init_main.c
+++ b/sys/kern/init_main.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: init_main.c,v 1.252 2016/05/10 23:54:00 bluhm Exp $	*/
+/*	$OpenBSD: init_main.c,v 1.253 2016/05/17 23:28:03 bluhm Exp $	*/
 /*	$NetBSD: init_main.c,v 1.84.4.1 1996/06/02 09:08:06 mrg Exp $	*/
 
 /*
@@ -120,7 +120,7 @@ struct	proc *reaperproc;
 
 extern	struct user *proc0paddr;
 
-struct	vnode *rootvp, *swapdev_vp, *consolevp;
+struct	vnode *rootvp, *swapdev_vp;
 int	boothowto;
 struct	timespec boottime;
 int	ncpus =  1;
@@ -133,7 +133,7 @@ long	__guard_local __attribute__((section(".openbsd.randomdata")));
 
 /* XXX return int so gcc -Werror won't complain */
 int	main(void *);
-void	open_console(struct proc *);
+void	check_console(struct proc *);
 void	start_init(void *);
 void	start_cleaner(void *);
 void	start_update(void *);
@@ -570,30 +570,20 @@ static char *initpaths[] = {
 };
 
 void
-open_console(struct proc *p)
+check_console(struct proc *p)
 {
 	struct nameidata nd;
-	struct vnode *vp;
 	int error;
 
 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, "/dev/console", p);
-	error = vn_open(&nd, FWRITE, 0);
+	error = namei(&nd);
 	if (error) {
 		if (error == ENOENT)
 			printf("warning: /dev/console does not exist\n");
 		else
 			printf("warning: /dev/console error %d\n", error);
-		return;
-	}
-	vp = nd.ni_vp;
-	VOP_UNLOCK(vp, p);
-	if (!ISSET(vp->v_flag, VISTTY)) {
-		printf("warning: /dev/console is not a tty device\n");
-		vn_close(vp, FWRITE, p->p_ucred, p);
-		return;
-	}
-
-	consolevp = vp;
+	} else
+		vrele(nd.ni_vp);
 }
 
 /*
@@ -626,7 +616,7 @@ start_init(void *arg)
 	while (start_init_exec == 0)
 		(void) tsleep((void *)&start_init_exec, PWAIT, "initexec", 0);
 
-	open_console(p);
+	check_console(p);
 
 	/* process 0 ignores SIGCHLD, but we can't */
 	p->p_p->ps_sigacts->ps_flags = 0;
diff --git a/sys/kern/subr_log.c b/sys/kern/subr_log.c
index 1d11ef02232..15ef3812152 100644
--- a/sys/kern/subr_log.c
+++ b/sys/kern/subr_log.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: subr_log.c,v 1.39 2016/05/10 23:54:00 bluhm Exp $	*/
+/*	$OpenBSD: subr_log.c,v 1.40 2016/05/17 23:28:03 bluhm Exp $	*/
 /*	$NetBSD: subr_log.c,v 1.11 1996/03/30 22:24:44 christos Exp $	*/
 
 /*
@@ -415,7 +415,7 @@ dosendsyslog(struct proc *p, const char *buf, size_t nbyte, int flags,
 
 	if (syslogf)
 		FREF(syslogf);
-	else if (!ISSET(flags, LOG_CONS) || consolevp == NULL)
+	else if (!ISSET(flags, LOG_CONS))
 		return (ENOTCONN);
 	else {
 		/*
diff --git a/sys/sys/systm.h b/sys/sys/systm.h
index 83e16052820..1c65c0387f0 100644
--- a/sys/sys/systm.h
+++ b/sys/sys/systm.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: systm.h,v 1.112 2016/05/10 23:54:01 bluhm Exp $	*/
+/*	$OpenBSD: systm.h,v 1.113 2016/05/17 23:28:03 bluhm Exp $	*/
 /*	$NetBSD: systm.h,v 1.50 1996/06/09 04:55:09 briggs Exp $	*/
 
 /*-
@@ -99,8 +99,6 @@ extern struct vnode *rootvp;	/* vnode equivalent to above */
 extern dev_t swapdev;		/* swapping device */
 extern struct vnode *swapdev_vp;/* vnode equivalent to above */
 
-extern struct vnode *consolevp; /* vnode of console tty device */
-
 struct proc;
 struct process;
 #define curproc curcpu()->ci_curproc