From c75556a12f51d0e4ecdc37fa278d1f28704dd413 Mon Sep 17 00:00:00 2001
From: fair <fair@NetBSD.org>
Date: Sun, 6 Feb 2000 07:29:56 +0000
Subject: [PATCH] Add kernel logging of processes which exit on signals which
 can cause a core to drop, and whether the core dropped, or, if it did not,
 why not (i.e. error number). Logs process ID, name, signal that hit it, and
 whether the core dump was successful.

logging only happens if kern_logsigexit is non-zero, and it can be
changed by the new sysctl(3) value KERN_LOGSIGEXIT. The name of this
sysctl and its function are taken from FreeBSD, at the suggestion
of Greg Woods in PR 6224. Default behavior is zero for a normal
kernel, and one for a kernel compiled with DIAGNOSTIC.
---
 sys/kern/kern_sig.c    | 29 +++++++++++++++++++++++++++--
 sys/kern/kern_sysctl.c |  5 ++++-
 sys/sys/sysctl.h       |  6 ++++--
 3 files changed, 35 insertions(+), 5 deletions(-)

diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c
index c36a877cac68..c0835b84dbd3 100644
--- a/sys/kern/kern_sig.c
+++ b/sys/kern/kern_sig.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: kern_sig.c,v 1.95 1999/12/30 16:00:23 eeh Exp $	*/
+/*	$NetBSD: kern_sig.c,v 1.96 2000/02/06 07:29:56 fair Exp $	*/
 
 /*
  * Copyright (c) 1982, 1986, 1989, 1991, 1993
@@ -1238,17 +1238,42 @@ killproc(p, why)
  * If dumping core, save the signal number for the debugger.  Calls exit and
  * does not return.
  */
+
+#if defined(DIAGNOSTIC) || defined(DEBUG)
+int	kern_logsigexit = 1;	/* not static to make public for sysctl */
+#else
+int	kern_logsigexit = 0;	/* not static to make public for sysctl */
+#endif
+
+static	char	*logcoredump =
+	"pid %d (%s), uid %d: exited on signal %d (core dumped)\n";
+static	char	*lognocoredump =
+	"pid %d (%s), uid %d: exited on signal %d (core not dumped, err = %d)\n";
+
 void
 sigexit(p, signum)
 	register struct proc *p;
 	int signum;
 {
+	int	error;
+	char	*errmsg;
+
 	p->p_acflag |= AXSIG;
 	if (sigprop[signum] & SA_CORE) {
 		p->p_sigacts->ps_sig = signum;
-		if (coredump(p) == 0)
+		if ((error = coredump(p)) == 0) {
 			signum |= WCOREFLAG;
+			errmsg = logcoredump;
+		} else {
+			errmsg = lognocoredump;
+		}
+
+		if (kern_logsigexit)
+			log(LOG_INFO, errmsg, p->p_pid, p->p_comm,
+			    p->p_cred && p->p_ucred ? p->p_ucred->cr_uid : -1,
+			    signum &~ WCOREFLAG, error);
 	}
+
 	exit1(p, W_EXITCODE(0, signum));
 	/* NOTREACHED */
 }
diff --git a/sys/kern/kern_sysctl.c b/sys/kern/kern_sysctl.c
index 5d43f543f74c..aea624754d87 100644
--- a/sys/kern/kern_sysctl.c
+++ b/sys/kern/kern_sysctl.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: kern_sysctl.c,v 1.56 2000/01/16 15:07:48 assar Exp $	*/
+/*	$NetBSD: kern_sysctl.c,v 1.57 2000/02/06 07:29:58 fair Exp $	*/
 
 /*-
  * Copyright (c) 1982, 1986, 1989, 1993
@@ -233,6 +233,7 @@ int defcorenamelen = sizeof(DEFCORENAME);
 char defcorename[MAXPATHLEN] = "%n.core";
 int defcorenamelen = sizeof("%n.core");
 #endif
+extern	int	kern_logsigexit;
 
 /*
  * kernel related system variables.
@@ -422,6 +423,8 @@ kern_sysctl(name, namelen, oldp, oldlenp, newp, newlen, p)
 		return (sysctl_rdint(oldp, oldlenp, newp, 1));
 	case KERN_LOGIN_NAME_MAX:
 		return (sysctl_rdint(oldp, oldlenp, newp, LOGIN_NAME_MAX));
+	case KERN_LOGSIGEXIT:
+		return (sysctl_int(oldp, oldlenp, newp, newlen, &kern_logsigexit));
 	default:
 		return (EOPNOTSUPP);
 	}
diff --git a/sys/sys/sysctl.h b/sys/sys/sysctl.h
index b85a7bb5205b..2d63651cdd27 100644
--- a/sys/sys/sysctl.h
+++ b/sys/sys/sysctl.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: sysctl.h,v 1.39 1999/11/19 10:41:41 bouyer Exp $	*/
+/*	$NetBSD: sysctl.h,v 1.40 2000/02/06 07:29:59 fair Exp $	*/
 
 /*
  * Copyright (c) 1989, 1993
@@ -157,7 +157,8 @@ struct ctlname {
 #define	KERN_MEMORY_PROTECTION	43	/* int: POSIX memory protections */
 #define	KERN_LOGIN_NAME_MAX	44	/* int: max length login name + NUL */
 #define	KERN_DEFCORENAME	45	/* old: sort core name format */
-#define	KERN_MAXID		46	/* number of valid kern ids */
+#define	KERN_LOGSIGEXIT		46	/* int: log signalled processes */
+#define	KERN_MAXID		47	/* number of valid kern ids */
 
 #define CTL_KERN_NAMES { \
 	{ 0, 0 }, \
@@ -206,6 +207,7 @@ struct ctlname {
 	{ "memory_protection", CTLTYPE_INT }, \
 	{ "login_name_max", CTLTYPE_INT }, \
 	{ "defcorename", CTLTYPE_STRING }, \
+	{ "logsigexit", CTLTYPE_INT }, \
 }
 
 /*