add a new check method which allows to run external scripts/programs

for custom evaluations.

pyr agrees to put it in now but to do some improvements of the timeout
handling later.

16 files changed, 532 insertions, 58 deletions

diff --git a/usr.sbin/hoststated/Makefile b/usr.sbin/hoststated/Makefile
index f59567497ac..83c2467d45f 100644
--- a/usr.sbin/hoststated/Makefile
+++ b/usr.sbin/hoststated/Makefile
@@ -1,9 +1,9 @@
-#	$OpenBSD: Makefile,v 1.11 2007/02/26 19:35:43 reyk Exp $
+#	$OpenBSD: Makefile,v 1.12 2007/05/29 17:12:04 reyk Exp $
 
 PROG=		hoststated
 SRCS=		parse.y log.c control.c buffer.c imsg.c hoststated.c	\
-		ssl.c pfe.c pfe_filter.c hce.c				\
-		check_icmp.c check_tcp.c relay.c carp.c
+		ssl.c pfe.c pfe_filter.c hce.c relay.c carp.c 		\
+		check_icmp.c check_tcp.c check_script.c
 MAN=		hoststated.8 hoststated.conf.5
 
 LDADD=		-levent -lssl -lcrypto
diff --git a/usr.sbin/hoststated/check_script.c b/usr.sbin/hoststated/check_script.c
new file mode 100644
index 00000000000..d347d882846
--- /dev/null
+++ b/usr.sbin/hoststated/check_script.c
@@ -0,0 +1,166 @@
+/*	$OpenBSD: check_script.c,v 1.1 2007/05/29 17:12:04 reyk Exp $	*/
+
+/*
+ * Copyright (c) 2007 Reyk Floeter <reyk@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/types.h>
+#include <sys/queue.h>
+#include <sys/socket.h>
+#include <sys/param.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+#include <net/if.h>
+
+#include <limits.h>
+#include <event.h>
+#include <errno.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <pwd.h>
+#include <err.h>
+
+#include <openssl/ssl.h>
+
+#include "hoststated.h"
+
+void	 script_sig_alarm(int);
+
+extern struct imsgbuf		*ibuf_main;
+pid_t				 child = -1;
+
+void
+check_script(struct host *host)
+{
+	struct ctl_script	 scr;
+
+	host->last_up = host->up;
+	host->flags &= ~(F_CHECK_SENT|F_CHECK_DONE);
+
+	scr.host = host->conf.id;
+	imsg_compose(ibuf_main, IMSG_SCRIPT, 0, 0, &scr, sizeof(scr));
+}
+
+void
+script_done(struct hoststated *env, struct ctl_script *scr)
+{
+	struct host		*host;
+
+	if ((host = host_find(env, scr->host)) == NULL)
+		fatalx("hce_dispatch_parent: invalid host id");
+
+	if (scr->retval < 0)
+		host->up = HOST_UNKNOWN;
+	else if (scr->retval == 0)
+		host->up = HOST_DOWN;
+	else
+		host->up = HOST_UP;
+	host->flags |= F_CHECK_DONE;
+
+	hce_notify_done(host, host->up == HOST_UP ?
+	    "script: done" : "script: failed");
+}
+
+void
+script_sig_alarm(int sig)
+{
+	if (child != -1)
+		kill(child, SIGKILL);
+}
+
+int
+script_exec(struct hoststated *env, struct ctl_script *scr)
+{
+	int			 status = 0, ret = 0;
+	sig_t			 save_quit, save_int, save_chld;
+	struct itimerval	 it;
+	struct timeval		*tv;
+	const char		*file, *arg;
+	struct host		*host;
+	struct table		*table;
+	struct passwd		*pw;
+
+	if ((host = host_find(env, scr->host)) == NULL)
+		fatalx("script_exec: invalid host id");
+	if ((table = table_find(env, host->conf.tableid)) == NULL)
+		fatalx("script_exec: invalid table id");
+
+	arg = host->conf.name;
+	file = table->conf.path;
+	tv = &table->conf.timeout;
+
+	save_quit = signal(SIGQUIT, SIG_IGN);
+	save_int = signal(SIGINT, SIG_IGN);
+	save_chld = signal(SIGCHLD, SIG_DFL);
+
+	switch (child = fork()) {
+	case -1:
+		ret = -1;
+		goto done;
+	case 0:
+		signal(SIGQUIT, SIG_DFL);
+		signal(SIGINT, SIG_DFL);
+		signal(SIGCHLD, SIG_DFL);
+
+		if ((pw = getpwnam(HOSTSTATED_USER)) == NULL)
+			fatal("script_exec: getpwnam");
+		if (chdir("/") == -1)
+			fatal("script_exec: chdir(\"/\")");
+		if (setgroups(1, &pw->pw_gid) ||
+		    setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) ||
+		    setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid))
+			fatal("script_exec: can't drop privileges");
+
+		execlp(file, file, arg, (char *)NULL);
+		_exit(0);
+		break;
+	default:
+		/* Kill the process after a timeout */
+		signal(SIGALRM, script_sig_alarm);
+		bzero(&it, sizeof(it));
+		bcopy(tv, &it.it_value, sizeof(it.it_value));
+		setitimer(ITIMER_REAL, &it, NULL);
+
+		waitpid(child, &status, 0);
+		break;
+	}
+
+	switch (ret) {
+	case -1:
+		ret = -1;
+		break;
+	default:
+		if (WIFEXITED(status))
+			ret = WEXITSTATUS(status);
+		else
+			ret = -1;
+	}
+
+ done:
+	/* Disable the process timeout timer */
+	bzero(&it, sizeof(it));
+	setitimer(ITIMER_REAL, &it, NULL);
+	child = -1;
+
+	signal(SIGQUIT, save_quit);
+	signal(SIGINT, save_int);
+	signal(SIGCHLD, save_chld);
+	signal(SIGALRM, SIG_DFL);
+
+	return (ret);
+}
diff --git a/usr.sbin/hoststated/hce.c b/usr.sbin/hoststated/hce.c
index 0110dfe7d22..139ef678b05 100644
--- a/usr.sbin/hoststated/hce.c
+++ b/usr.sbin/hoststated/hce.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: hce.c,v 1.21 2007/05/28 22:11:33 pyr Exp $	*/
+/*	$OpenBSD: hce.c,v 1.22 2007/05/29 17:12:04 reyk Exp $	*/
 
 /*
  * Copyright (c) 2006 Pierre-Yves Ritschard <pyr@spootnik.org>
@@ -46,7 +46,7 @@ void	hce_dispatch_imsg(int, short, void *);
 void	hce_dispatch_parent(int, short, void *);
 void	hce_launch_checks(int, short, void *);
 
-static struct hoststated	*env = NULL;
+static struct hoststated *env = NULL;
 struct imsgbuf		*ibuf_pfe;
 struct imsgbuf		*ibuf_main;
 
@@ -194,19 +194,24 @@ hce_launch_checks(int fd, short event, void *arg)
 		TAILQ_FOREACH(host, &table->hosts, entry) {
 			if (host->flags & F_DISABLE)
 				continue;
-			if (table->conf.check == CHECK_ICMP) {
+			switch (table->conf.check) {
+			case CHECK_ICMP:
 				schedule_icmp(env, host);
-				continue;
+				break;
+			case CHECK_SCRIPT:
+				check_script(host);
+				break;
+			default:
+				/* Any other TCP-style checks */
+				bzero(&host->cte, sizeof(host->cte));
+				host->last_up = host->up;
+				host->cte.host = host;
+				host->cte.table = table;
+				bcopy(&tv, &host->cte.tv_start,
+				    sizeof(host->cte.tv_start));
+				check_tcp(&host->cte);
+				break;
 			}
-
-			/* Any other TCP-style checks */
-			bzero(&host->cte, sizeof(host->cte));
-			host->last_up = host->up;
-			host->cte.host = host;
-			host->cte.table = table;
-			bcopy(&tv, &host->cte.tv_start,
-			    sizeof(host->cte.tv_start));
-			check_tcp(&host->cte);
 		}
 	}
 	check_icmp(env, &tv);
@@ -359,9 +364,10 @@ hce_dispatch_imsg(int fd, short event, void *ptr)
 void
 hce_dispatch_parent(int fd, short event, void * ptr)
 {
-	struct imsgbuf	*ibuf;
-	struct imsg	 imsg;
-	ssize_t		 n;
+	struct imsgbuf		*ibuf;
+	struct imsg		 imsg;
+	struct ctl_script	 scr;
+	ssize_t		 	 n;
 
 	ibuf = ptr;
 	switch (event) {
@@ -387,6 +393,14 @@ hce_dispatch_parent(int fd, short event, void * ptr)
 			break;
 
 		switch (imsg.hdr.type) {
+		case IMSG_SCRIPT:
+			if (imsg.hdr.len - IMSG_HEADER_SIZE !=
+			    sizeof(scr))
+				fatalx("hce_dispatch_parent: "
+				    "invalid size of script request");
+			bcopy(imsg.data, &scr, sizeof(scr));
+			script_done(env, &scr);
+			break;
 		default:
 			log_debug("hce_dispatch_parent: unexpected imsg %d",
 			    imsg.hdr.type);
@@ -394,4 +408,5 @@ hce_dispatch_parent(int fd, short event, void * ptr)
 		}
 		imsg_free(&imsg);
 	}
+	imsg_event_add(ibuf);
 }
diff --git a/usr.sbin/hoststated/hoststated.c b/usr.sbin/hoststated/hoststated.c
index f48ba94e18c..ad04abc7f59 100644
--- a/usr.sbin/hoststated/hoststated.c
+++ b/usr.sbin/hoststated/hoststated.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: hoststated.c,v 1.26 2007/05/29 00:58:06 pyr Exp $	*/
+/*	$OpenBSD: hoststated.c,v 1.27 2007/05/29 17:12:04 reyk Exp $	*/
 
 /*
  * Copyright (c) 2006 Pierre-Yves Ritschard <pyr@spootnik.org>
@@ -54,6 +54,8 @@ int		 pipe_pfe2hce[2];
 int		 pipe_parent2relay[RELAY_MAXPROC][2];
 int		 pipe_pfe2relay[RELAY_MAXPROC][2];
 
+struct hoststated	*hoststated_env;
+
 struct imsgbuf	*ibuf_pfe;
 struct imsgbuf	*ibuf_hce;
 struct imsgbuf	*ibuf_relay;
@@ -68,8 +70,6 @@ main_sig_handler(int sig, short event, void *arg)
 	struct hoststated	*env = arg;
 	int			 die = 0;
 
-	log_debug("signal %d", sig);
-
 	switch (sig) {
 	case SIGTERM:
 	case SIGINT:
@@ -154,6 +154,7 @@ main(int argc, char *argv[])
 
 	if ((env = parse_config(conffile, opts)) == NULL)
 		exit(1);
+	hoststated_env = env;
 
 	if (env->opts & HOSTSTATED_OPT_NOACTION) {
 		fprintf(stderr, "configuration OK\n");
@@ -485,7 +486,10 @@ main_dispatch_hce(int fd, short event, void * ptr)
 	struct imsgbuf		*ibuf;
 	struct imsg		 imsg;
 	ssize_t			 n;
+	struct ctl_script	 scr;
+	struct hoststated	*env;
 
+	env = hoststated_env;
 	ibuf = ptr;
 	switch (event) {
 	case EV_READ:
@@ -510,6 +514,16 @@ main_dispatch_hce(int fd, short event, void * ptr)
 			break;
 
 		switch (imsg.hdr.type) {
+		case IMSG_SCRIPT:
+			if (imsg.hdr.len - IMSG_HEADER_SIZE !=
+			    sizeof(scr))
+				fatalx("main_dispatch_hce: "
+				    "invalid size of script request");
+			bcopy(imsg.data, &scr, sizeof(scr));
+			scr.retval = script_exec(env, &scr);
+			imsg_compose(ibuf_hce, IMSG_SCRIPT,
+			    0, 0, &scr, sizeof(scr));
+			break;
 		default:
 			log_debug("main_dispatch_hce: unexpected imsg %d",
 			    imsg.hdr.type);
@@ -517,6 +531,7 @@ main_dispatch_hce(int fd, short event, void * ptr)
 		}
 		imsg_free(&imsg);
 	}
+	imsg_event_add(ibuf);
 }
 
 void
diff --git a/usr.sbin/hoststated/hoststated.conf.5 b/usr.sbin/hoststated/hoststated.conf.5
index 99330d9546a..d197c824984 100644
--- a/usr.sbin/hoststated/hoststated.conf.5
+++ b/usr.sbin/hoststated/hoststated.conf.5
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: hoststated.conf.5,v 1.43 2007/05/27 19:21:15 reyk Exp $
+.\"	$OpenBSD: hoststated.conf.5,v 1.44 2007/05/29 17:12:04 reyk Exp $
 .\"
 .\" Copyright (c) 2006 Pierre-Yves Ritschard <pyr@spootnik.org>
 .\"
@@ -204,6 +204,21 @@ If the
 .Ic ssl
 keyword is present,
 the transaction will occur in an SSL tunnel.
+.It Ic check script Ar path
+Execute an external program to check the host state.
+The program will be executed for each host by specifing the host name
+on the command line:
+.Bd -literal -offset indent
+/usr/local/bin/checkload.pl front-www1.private.example.com
+.Ed
+.Pp
+.Xr hoststated 8
+expects a positive return value on success and zero on failure.
+Note that the script will be executed with the privileges of the
+.Qq _hoststated
+user and terminated after
+.Ar timeout
+milliseconds.
 .It Ic check ssl
 Perform a complete SSL handshake with each host to check their availability.
 .It Ic check tcp
diff --git a/usr.sbin/hoststated/hoststated.h b/usr.sbin/hoststated/hoststated.h
index 036ce7aec4f..ed8cde04204 100644
--- a/usr.sbin/hoststated/hoststated.h
+++ b/usr.sbin/hoststated/hoststated.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: hoststated.h,v 1.47 2007/05/29 00:48:04 pyr Exp $	*/
+/*	$OpenBSD: hoststated.h,v 1.48 2007/05/29 17:12:04 reyk Exp $	*/
 
 /*
  * Copyright (c) 2006, 2007 Pierre-Yves Ritschard <pyr@spootnik.org>
@@ -125,7 +125,8 @@ enum imsg_type {
 	IMSG_DEMOTE,
 	IMSG_STATISTICS,
 	IMSG_RECONF,		/* reconfiguration notifies */
-	IMSG_RECONF_END
+	IMSG_RECONF_END,
+	IMSG_SCRIPT
 };
 
 struct imsg_hdr {
@@ -154,6 +155,11 @@ struct ctl_id {
 	char		 name[MAX_NAME_SIZE];
 };
 
+struct ctl_script {
+	objid_t		 host;
+	int		 retval;
+};
+
 struct ctl_demote {
 	char		 group[IFNAMSIZ];
 	int		 level;
@@ -342,7 +348,8 @@ enum table_check {
 	CHECK_TCP		= 2,
 	CHECK_HTTP_CODE		= 3,
 	CHECK_HTTP_DIGEST	= 4,
-	CHECK_SEND_EXPECT	= 5
+	CHECK_SEND_EXPECT	= 5,
+	CHECK_SCRIPT		= 6
 };
 
 struct service_config {
@@ -675,6 +682,11 @@ void	 check_icmp(struct hoststated *, struct timeval *);
 /* check_tcp.c */
 void	 check_tcp(struct ctl_tcp_event *);
 
+/* check_script.c */
+void	 check_script(struct host *);
+void	 script_done(struct hoststated *, struct ctl_script *);
+int	 script_exec(struct hoststated *, struct ctl_script *);
+
 /* ssl.c */
 void	 ssl_init(struct hoststated *);
 void	 ssl_transaction(struct ctl_tcp_event *);
diff --git a/usr.sbin/hoststated/log.c b/usr.sbin/hoststated/log.c
index 0da3432ca88..e3ef97f502a 100644
--- a/usr.sbin/hoststated/log.c
+++ b/usr.sbin/hoststated/log.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: log.c,v 1.4 2007/02/22 03:32:39 reyk Exp $	*/
+/*	$OpenBSD: log.c,v 1.5 2007/05/29 17:12:04 reyk Exp $	*/
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -196,6 +196,8 @@ table_check(enum table_check check)
 		return ("http digest");
 	case CHECK_SEND_EXPECT:
 		return ("send expect");
+	case CHECK_SCRIPT:
+		return ("script");
 	};
 	/* NOTREACHED */
 	return ("invalid");
diff --git a/usr.sbin/hoststated/parse.y b/usr.sbin/hoststated/parse.y
index 88c1c1c93a1..49f89707f0d 100644
--- a/usr.sbin/hoststated/parse.y
+++ b/usr.sbin/hoststated/parse.y
@@ -1,4 +1,4 @@
-/*	$OpenBSD: parse.y,v 1.44 2007/05/29 00:48:04 pyr Exp $	*/
+/*	$OpenBSD: parse.y,v 1.45 2007/05/29 17:12:04 reyk Exp $	*/
 
 /*
  * Copyright (c) 2006 Pierre-Yves Ritschard <pyr@spootnik.org>
@@ -108,7 +108,7 @@ typedef struct {
 %token	SERVICE TABLE BACKUP HOST REAL
 %token  CHECK TCP ICMP EXTERNAL REQUEST RESPONSE
 %token  TIMEOUT CODE DIGEST PORT TAG INTERFACE
-%token	VIRTUAL INTERVAL DISABLE STICKYADDR BACKLOG PATH
+%token	VIRTUAL INTERVAL DISABLE STICKYADDR BACKLOG PATH SCRIPT
 %token	SEND EXPECT NOTHING SSL LOADBALANCE ROUNDROBIN CIPHERS COOKIE
 %token	RELAY LISTEN ON FORWARD TO NAT LOOKUP PREFORK NO MARK MARKED
 %token	PROTO SESSION CACHE APPEND CHANGE REMOVE FROM FILTER HASH HEADER
@@ -508,6 +508,17 @@ tableoptsl	: host			{
 			}
 			free($5);
 		}
+		| CHECK SCRIPT STRING {
+			table->conf.check = CHECK_SCRIPT;
+			if (strlcpy(table->conf.path, $3,
+			    sizeof(table->conf.path)) >=
+			    sizeof(table->conf.path)) {
+				yyerror("script path truncated");
+				free($3);
+				YYERROR;
+			}
+			free($3);
+		}
 		| REAL port {
 			table->conf.port = $2;
 		}
@@ -1167,6 +1178,7 @@ lookup(char *s)
 		{ "retry",		RETRY },
 		{ "roundrobin",		ROUNDROBIN },
 		{ "sack",		SACK },
+		{ "script",		SCRIPT },
 		{ "send",		SEND },
 		{ "service",		SERVICE },
 		{ "session",		SESSION },
diff --git a/usr.sbin/relayd/Makefile b/usr.sbin/relayd/Makefile
index f59567497ac..83c2467d45f 100644
--- a/usr.sbin/relayd/Makefile
+++ b/usr.sbin/relayd/Makefile
@@ -1,9 +1,9 @@
-#	$OpenBSD: Makefile,v 1.11 2007/02/26 19:35:43 reyk Exp $
+#	$OpenBSD: Makefile,v 1.12 2007/05/29 17:12:04 reyk Exp $
 
 PROG=		hoststated
 SRCS=		parse.y log.c control.c buffer.c imsg.c hoststated.c	\
-		ssl.c pfe.c pfe_filter.c hce.c				\
-		check_icmp.c check_tcp.c relay.c carp.c
+		ssl.c pfe.c pfe_filter.c hce.c relay.c carp.c 		\
+		check_icmp.c check_tcp.c check_script.c
 MAN=		hoststated.8 hoststated.conf.5
 
 LDADD=		-levent -lssl -lcrypto
diff --git a/usr.sbin/relayd/check_script.c b/usr.sbin/relayd/check_script.c
new file mode 100644
index 00000000000..d347d882846
--- /dev/null
+++ b/usr.sbin/relayd/check_script.c
@@ -0,0 +1,166 @@
+/*	$OpenBSD: check_script.c,v 1.1 2007/05/29 17:12:04 reyk Exp $	*/
+
+/*
+ * Copyright (c) 2007 Reyk Floeter <reyk@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/types.h>
+#include <sys/queue.h>
+#include <sys/socket.h>
+#include <sys/param.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+#include <net/if.h>
+
+#include <limits.h>
+#include <event.h>
+#include <errno.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <pwd.h>
+#include <err.h>
+
+#include <openssl/ssl.h>
+
+#include "hoststated.h"
+
+void	 script_sig_alarm(int);
+
+extern struct imsgbuf		*ibuf_main;
+pid_t				 child = -1;
+
+void
+check_script(struct host *host)
+{
+	struct ctl_script	 scr;
+
+	host->last_up = host->up;
+	host->flags &= ~(F_CHECK_SENT|F_CHECK_DONE);
+
+	scr.host = host->conf.id;
+	imsg_compose(ibuf_main, IMSG_SCRIPT, 0, 0, &scr, sizeof(scr));
+}
+
+void
+script_done(struct hoststated *env, struct ctl_script *scr)
+{
+	struct host		*host;
+
+	if ((host = host_find(env, scr->host)) == NULL)
+		fatalx("hce_dispatch_parent: invalid host id");
+
+	if (scr->retval < 0)
+		host->up = HOST_UNKNOWN;
+	else if (scr->retval == 0)
+		host->up = HOST_DOWN;
+	else
+		host->up = HOST_UP;
+	host->flags |= F_CHECK_DONE;
+
+	hce_notify_done(host, host->up == HOST_UP ?
+	    "script: done" : "script: failed");
+}
+
+void
+script_sig_alarm(int sig)
+{
+	if (child != -1)
+		kill(child, SIGKILL);
+}
+
+int
+script_exec(struct hoststated *env, struct ctl_script *scr)
+{
+	int			 status = 0, ret = 0;
+	sig_t			 save_quit, save_int, save_chld;
+	struct itimerval	 it;
+	struct timeval		*tv;
+	const char		*file, *arg;
+	struct host		*host;
+	struct table		*table;
+	struct passwd		*pw;
+
+	if ((host = host_find(env, scr->host)) == NULL)
+		fatalx("script_exec: invalid host id");
+	if ((table = table_find(env, host->conf.tableid)) == NULL)
+		fatalx("script_exec: invalid table id");
+
+	arg = host->conf.name;
+	file = table->conf.path;
+	tv = &table->conf.timeout;
+
+	save_quit = signal(SIGQUIT, SIG_IGN);
+	save_int = signal(SIGINT, SIG_IGN);
+	save_chld = signal(SIGCHLD, SIG_DFL);
+
+	switch (child = fork()) {
+	case -1:
+		ret = -1;
+		goto done;
+	case 0:
+		signal(SIGQUIT, SIG_DFL);
+		signal(SIGINT, SIG_DFL);
+		signal(SIGCHLD, SIG_DFL);
+
+		if ((pw = getpwnam(HOSTSTATED_USER)) == NULL)
+			fatal("script_exec: getpwnam");
+		if (chdir("/") == -1)
+			fatal("script_exec: chdir(\"/\")");
+		if (setgroups(1, &pw->pw_gid) ||
+		    setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) ||
+		    setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid))
+			fatal("script_exec: can't drop privileges");
+
+		execlp(file, file, arg, (char *)NULL);
+		_exit(0);
+		break;
+	default:
+		/* Kill the process after a timeout */
+		signal(SIGALRM, script_sig_alarm);
+		bzero(&it, sizeof(it));
+		bcopy(tv, &it.it_value, sizeof(it.it_value));
+		setitimer(ITIMER_REAL, &it, NULL);
+
+		waitpid(child, &status, 0);
+		break;
+	}
+
+	switch (ret) {
+	case -1:
+		ret = -1;
+		break;
+	default:
+		if (WIFEXITED(status))
+			ret = WEXITSTATUS(status);
+		else
+			ret = -1;
+	}
+
+ done:
+	/* Disable the process timeout timer */
+	bzero(&it, sizeof(it));
+	setitimer(ITIMER_REAL, &it, NULL);
+	child = -1;
+
+	signal(SIGQUIT, save_quit);
+	signal(SIGINT, save_int);
+	signal(SIGCHLD, save_chld);
+	signal(SIGALRM, SIG_DFL);
+
+	return (ret);
+}
diff --git a/usr.sbin/relayd/hce.c b/usr.sbin/relayd/hce.c
index 0110dfe7d22..139ef678b05 100644
--- a/usr.sbin/relayd/hce.c
+++ b/usr.sbin/relayd/hce.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: hce.c,v 1.21 2007/05/28 22:11:33 pyr Exp $	*/
+/*	$OpenBSD: hce.c,v 1.22 2007/05/29 17:12:04 reyk Exp $	*/
 
 /*
  * Copyright (c) 2006 Pierre-Yves Ritschard <pyr@spootnik.org>
@@ -46,7 +46,7 @@ void	hce_dispatch_imsg(int, short, void *);
 void	hce_dispatch_parent(int, short, void *);
 void	hce_launch_checks(int, short, void *);
 
-static struct hoststated	*env = NULL;
+static struct hoststated *env = NULL;
 struct imsgbuf		*ibuf_pfe;
 struct imsgbuf		*ibuf_main;
 
@@ -194,19 +194,24 @@ hce_launch_checks(int fd, short event, void *arg)
 		TAILQ_FOREACH(host, &table->hosts, entry) {
 			if (host->flags & F_DISABLE)
 				continue;
-			if (table->conf.check == CHECK_ICMP) {
+			switch (table->conf.check) {
+			case CHECK_ICMP:
 				schedule_icmp(env, host);
-				continue;
+				break;
+			case CHECK_SCRIPT:
+				check_script(host);
+				break;
+			default:
+				/* Any other TCP-style checks */
+				bzero(&host->cte, sizeof(host->cte));
+				host->last_up = host->up;
+				host->cte.host = host;
+				host->cte.table = table;
+				bcopy(&tv, &host->cte.tv_start,
+				    sizeof(host->cte.tv_start));
+				check_tcp(&host->cte);
+				break;
 			}
-
-			/* Any other TCP-style checks */
-			bzero(&host->cte, sizeof(host->cte));
-			host->last_up = host->up;
-			host->cte.host = host;
-			host->cte.table = table;
-			bcopy(&tv, &host->cte.tv_start,
-			    sizeof(host->cte.tv_start));
-			check_tcp(&host->cte);
 		}
 	}
 	check_icmp(env, &tv);
@@ -359,9 +364,10 @@ hce_dispatch_imsg(int fd, short event, void *ptr)
 void
 hce_dispatch_parent(int fd, short event, void * ptr)
 {
-	struct imsgbuf	*ibuf;
-	struct imsg	 imsg;
-	ssize_t		 n;
+	struct imsgbuf		*ibuf;
+	struct imsg		 imsg;
+	struct ctl_script	 scr;
+	ssize_t		 	 n;
 
 	ibuf = ptr;
 	switch (event) {
@@ -387,6 +393,14 @@ hce_dispatch_parent(int fd, short event, void * ptr)
 			break;
 
 		switch (imsg.hdr.type) {
+		case IMSG_SCRIPT:
+			if (imsg.hdr.len - IMSG_HEADER_SIZE !=
+			    sizeof(scr))
+				fatalx("hce_dispatch_parent: "
+				    "invalid size of script request");
+			bcopy(imsg.data, &scr, sizeof(scr));
+			script_done(env, &scr);
+			break;
 		default:
 			log_debug("hce_dispatch_parent: unexpected imsg %d",
 			    imsg.hdr.type);
@@ -394,4 +408,5 @@ hce_dispatch_parent(int fd, short event, void * ptr)
 		}
 		imsg_free(&imsg);
 	}
+	imsg_event_add(ibuf);
 }
diff --git a/usr.sbin/relayd/log.c b/usr.sbin/relayd/log.c
index 0da3432ca88..e3ef97f502a 100644
--- a/usr.sbin/relayd/log.c
+++ b/usr.sbin/relayd/log.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: log.c,v 1.4 2007/02/22 03:32:39 reyk Exp $	*/
+/*	$OpenBSD: log.c,v 1.5 2007/05/29 17:12:04 reyk Exp $	*/
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -196,6 +196,8 @@ table_check(enum table_check check)
 		return ("http digest");
 	case CHECK_SEND_EXPECT:
 		return ("send expect");
+	case CHECK_SCRIPT:
+		return ("script");
 	};
 	/* NOTREACHED */
 	return ("invalid");
diff --git a/usr.sbin/relayd/parse.y b/usr.sbin/relayd/parse.y
index 88c1c1c93a1..49f89707f0d 100644
--- a/usr.sbin/relayd/parse.y
+++ b/usr.sbin/relayd/parse.y
@@ -1,4 +1,4 @@
-/*	$OpenBSD: parse.y,v 1.44 2007/05/29 00:48:04 pyr Exp $	*/
+/*	$OpenBSD: parse.y,v 1.45 2007/05/29 17:12:04 reyk Exp $	*/
 
 /*
  * Copyright (c) 2006 Pierre-Yves Ritschard <pyr@spootnik.org>
@@ -108,7 +108,7 @@ typedef struct {
 %token	SERVICE TABLE BACKUP HOST REAL
 %token  CHECK TCP ICMP EXTERNAL REQUEST RESPONSE
 %token  TIMEOUT CODE DIGEST PORT TAG INTERFACE
-%token	VIRTUAL INTERVAL DISABLE STICKYADDR BACKLOG PATH
+%token	VIRTUAL INTERVAL DISABLE STICKYADDR BACKLOG PATH SCRIPT
 %token	SEND EXPECT NOTHING SSL LOADBALANCE ROUNDROBIN CIPHERS COOKIE
 %token	RELAY LISTEN ON FORWARD TO NAT LOOKUP PREFORK NO MARK MARKED
 %token	PROTO SESSION CACHE APPEND CHANGE REMOVE FROM FILTER HASH HEADER
@@ -508,6 +508,17 @@ tableoptsl	: host			{
 			}
 			free($5);
 		}
+		| CHECK SCRIPT STRING {
+			table->conf.check = CHECK_SCRIPT;
+			if (strlcpy(table->conf.path, $3,
+			    sizeof(table->conf.path)) >=
+			    sizeof(table->conf.path)) {
+				yyerror("script path truncated");
+				free($3);
+				YYERROR;
+			}
+			free($3);
+		}
 		| REAL port {
 			table->conf.port = $2;
 		}
@@ -1167,6 +1178,7 @@ lookup(char *s)
 		{ "retry",		RETRY },
 		{ "roundrobin",		ROUNDROBIN },
 		{ "sack",		SACK },
+		{ "script",		SCRIPT },
 		{ "send",		SEND },
 		{ "service",		SERVICE },
 		{ "session",		SESSION },
diff --git a/usr.sbin/relayd/relayd.c b/usr.sbin/relayd/relayd.c
index 9f20b1a90b1..83fc992c732 100644
--- a/usr.sbin/relayd/relayd.c
+++ b/usr.sbin/relayd/relayd.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: relayd.c,v 1.26 2007/05/29 00:58:06 pyr Exp $	*/
+/*	$OpenBSD: relayd.c,v 1.27 2007/05/29 17:12:04 reyk Exp $	*/
 
 /*
  * Copyright (c) 2006 Pierre-Yves Ritschard <pyr@spootnik.org>
@@ -54,6 +54,8 @@ int		 pipe_pfe2hce[2];
 int		 pipe_parent2relay[RELAY_MAXPROC][2];
 int		 pipe_pfe2relay[RELAY_MAXPROC][2];
 
+struct hoststated	*hoststated_env;
+
 struct imsgbuf	*ibuf_pfe;
 struct imsgbuf	*ibuf_hce;
 struct imsgbuf	*ibuf_relay;
@@ -68,8 +70,6 @@ main_sig_handler(int sig, short event, void *arg)
 	struct hoststated	*env = arg;
 	int			 die = 0;
 
-	log_debug("signal %d", sig);
-
 	switch (sig) {
 	case SIGTERM:
 	case SIGINT:
@@ -154,6 +154,7 @@ main(int argc, char *argv[])
 
 	if ((env = parse_config(conffile, opts)) == NULL)
 		exit(1);
+	hoststated_env = env;
 
 	if (env->opts & HOSTSTATED_OPT_NOACTION) {
 		fprintf(stderr, "configuration OK\n");
@@ -485,7 +486,10 @@ main_dispatch_hce(int fd, short event, void * ptr)
 	struct imsgbuf		*ibuf;
 	struct imsg		 imsg;
 	ssize_t			 n;
+	struct ctl_script	 scr;
+	struct hoststated	*env;
 
+	env = hoststated_env;
 	ibuf = ptr;
 	switch (event) {
 	case EV_READ:
@@ -510,6 +514,16 @@ main_dispatch_hce(int fd, short event, void * ptr)
 			break;
 
 		switch (imsg.hdr.type) {
+		case IMSG_SCRIPT:
+			if (imsg.hdr.len - IMSG_HEADER_SIZE !=
+			    sizeof(scr))
+				fatalx("main_dispatch_hce: "
+				    "invalid size of script request");
+			bcopy(imsg.data, &scr, sizeof(scr));
+			scr.retval = script_exec(env, &scr);
+			imsg_compose(ibuf_hce, IMSG_SCRIPT,
+			    0, 0, &scr, sizeof(scr));
+			break;
 		default:
 			log_debug("main_dispatch_hce: unexpected imsg %d",
 			    imsg.hdr.type);
@@ -517,6 +531,7 @@ main_dispatch_hce(int fd, short event, void * ptr)
 		}
 		imsg_free(&imsg);
 	}
+	imsg_event_add(ibuf);
 }
 
 void
diff --git a/usr.sbin/relayd/relayd.conf.5 b/usr.sbin/relayd/relayd.conf.5
index 62056584def..5bf06abb520 100644
--- a/usr.sbin/relayd/relayd.conf.5
+++ b/usr.sbin/relayd/relayd.conf.5
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: relayd.conf.5,v 1.43 2007/05/27 19:21:15 reyk Exp $
+.\"	$OpenBSD: relayd.conf.5,v 1.44 2007/05/29 17:12:04 reyk Exp $
 .\"
 .\" Copyright (c) 2006 Pierre-Yves Ritschard <pyr@spootnik.org>
 .\"
@@ -204,6 +204,21 @@ If the
 .Ic ssl
 keyword is present,
 the transaction will occur in an SSL tunnel.
+.It Ic check script Ar path
+Execute an external program to check the host state.
+The program will be executed for each host by specifing the host name
+on the command line:
+.Bd -literal -offset indent
+/usr/local/bin/checkload.pl front-www1.private.example.com
+.Ed
+.Pp
+.Xr hoststated 8
+expects a positive return value on success and zero on failure.
+Note that the script will be executed with the privileges of the
+.Qq _hoststated
+user and terminated after
+.Ar timeout
+milliseconds.
 .It Ic check ssl
 Perform a complete SSL handshake with each host to check their availability.
 .It Ic check tcp
diff --git a/usr.sbin/relayd/relayd.h b/usr.sbin/relayd/relayd.h
index c92d9391560..8c66b958485 100644
--- a/usr.sbin/relayd/relayd.h
+++ b/usr.sbin/relayd/relayd.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: relayd.h,v 1.47 2007/05/29 00:48:04 pyr Exp $	*/
+/*	$OpenBSD: relayd.h,v 1.48 2007/05/29 17:12:04 reyk Exp $	*/
 
 /*
  * Copyright (c) 2006, 2007 Pierre-Yves Ritschard <pyr@spootnik.org>
@@ -125,7 +125,8 @@ enum imsg_type {
 	IMSG_DEMOTE,
 	IMSG_STATISTICS,
 	IMSG_RECONF,		/* reconfiguration notifies */
-	IMSG_RECONF_END
+	IMSG_RECONF_END,
+	IMSG_SCRIPT
 };
 
 struct imsg_hdr {
@@ -154,6 +155,11 @@ struct ctl_id {
 	char		 name[MAX_NAME_SIZE];
 };
 
+struct ctl_script {
+	objid_t		 host;
+	int		 retval;
+};
+
 struct ctl_demote {
 	char		 group[IFNAMSIZ];
 	int		 level;
@@ -342,7 +348,8 @@ enum table_check {
 	CHECK_TCP		= 2,
 	CHECK_HTTP_CODE		= 3,
 	CHECK_HTTP_DIGEST	= 4,
-	CHECK_SEND_EXPECT	= 5
+	CHECK_SEND_EXPECT	= 5,
+	CHECK_SCRIPT		= 6
 };
 
 struct service_config {
@@ -675,6 +682,11 @@ void	 check_icmp(struct hoststated *, struct timeval *);
 /* check_tcp.c */
 void	 check_tcp(struct ctl_tcp_event *);
 
+/* check_script.c */
+void	 check_script(struct host *);
+void	 script_done(struct hoststated *, struct ctl_script *);
+int	 script_exec(struct hoststated *, struct ctl_script *);
+
 /* ssl.c */
 void	 ssl_init(struct hoststated *);
 void	 ssl_transaction(struct ctl_tcp_event *);