When becoming a daemon, dup stdin, stdout, and stderr to /dev/null

Change an unsafe vfork() to fork()
Fix dup2() usage--must check for oldd == newd case and no need to close oldd
Fixes annoying messages from sendmail about stdout being closed.

5 files changed, 40 insertions, 25 deletions

diff --git a/usr.sbin/cron/cron.c b/usr.sbin/cron/cron.c
index a2ce0eba63a..5cc8a5458f5 100644
--- a/usr.sbin/cron/cron.c
+++ b/usr.sbin/cron/cron.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cron.c,v 1.15 2001/08/11 20:47:14 millert Exp $	*/
+/*	$OpenBSD: cron.c,v 1.16 2001/10/24 17:28:16 millert Exp $	*/
 /* Copyright 1988,1990,1993,1994 by Paul Vixie
  * All rights reserved
  */
@@ -21,7 +21,7 @@
  */
 
 #if !defined(lint) && !defined(LINT)
-static char rcsid[] = "$OpenBSD: cron.c,v 1.15 2001/08/11 20:47:14 millert Exp $";
+static char rcsid[] = "$OpenBSD: cron.c,v 1.16 2001/10/24 17:28:16 millert Exp $";
 #endif
 
 #define	MAIN_PROGRAM
@@ -57,6 +57,7 @@ int
 main(int argc, char *argv[]) {
 	cron_db	database;
 	struct sigaction sact;
+	int fd;
 
 	ProgramName = argv[0];
 
@@ -105,6 +106,13 @@ main(int argc, char *argv[]) {
 			/* child process */
 			log_it("CRON",getpid(),"STARTUP","fork ok");
 			(void) setsid();
+			if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
+				(void) dup2(fd, STDIN);
+				(void) dup2(fd, STDOUT);
+				(void) dup2(fd, STDERR);
+				if (fd > STDERR)
+					(void) close(fd);
+			}
 			break;
 		default:
 			/* parent process should just die */
diff --git a/usr.sbin/cron/crontab.c b/usr.sbin/cron/crontab.c
index fee68e0670a..e3cc15b630a 100644
--- a/usr.sbin/cron/crontab.c
+++ b/usr.sbin/cron/crontab.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: crontab.c,v 1.22 2001/08/19 18:30:38 millert Exp $	*/
+/*	$OpenBSD: crontab.c,v 1.23 2001/10/24 17:28:16 millert Exp $	*/
 /* Copyright 1988,1990,1993,1994 by Paul Vixie
  * All rights reserved
  */
@@ -21,7 +21,7 @@
  */
 
 #if !defined(lint) && !defined(LINT)
-static char rcsid[] = "$OpenBSD: crontab.c,v 1.22 2001/08/19 18:30:38 millert Exp $";
+static char rcsid[] = "$OpenBSD: crontab.c,v 1.23 2001/10/24 17:28:16 millert Exp $";
 #endif
 
 /* crontab - install and manage per-user crontab files
@@ -303,8 +303,8 @@ edit_cmd(void) {
 		}
 		fprintf(stderr, "no crontab for %s - using an empty one\n",
 			User);
-		if (!(f = fopen("/dev/null", "r"))) {
-			perror("/dev/null");
+		if (!(f = fopen(_PATH_DEVNULL, "r"))) {
+			perror(_PATH_DEVNULL);
 			exit(ERROR_EXIT);
 		}
 	}
diff --git a/usr.sbin/cron/do_command.c b/usr.sbin/cron/do_command.c
index 120aaacd905..c3c70bcf4a4 100644
--- a/usr.sbin/cron/do_command.c
+++ b/usr.sbin/cron/do_command.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: do_command.c,v 1.10 2001/02/18 19:48:33 millert Exp $	*/
+/*	$OpenBSD: do_command.c,v 1.11 2001/10/24 17:28:16 millert Exp $	*/
 /* Copyright 1988,1990,1993,1994 by Paul Vixie
  * All rights reserved
  */
@@ -21,7 +21,7 @@
  */
 
 #if !defined(lint) && !defined(LINT)
-static char rcsid[] = "$OpenBSD: do_command.c,v 1.10 2001/02/18 19:48:33 millert Exp $";
+static char rcsid[] = "$OpenBSD: do_command.c,v 1.11 2001/10/24 17:28:16 millert Exp $";
 #endif
 
 #include "cron.h"
@@ -139,7 +139,7 @@ child_process(entry *e, user *u) {
 
 	/* fork again, this time so we can exec the user's command.
 	 */
-	switch (vfork()) {
+	switch (fork()) {
 	case -1:
 		log_it("CRON", getpid(), "error", "can't vfork");
 		exit(ERROR_EXIT);
@@ -182,14 +182,15 @@ child_process(entry *e, user *u) {
 		/* grandchild process.  make std{in,out} be the ends of
 		 * pipes opened by our daddy; make stderr go to stdout.
 		 */
-		close(STDIN);	dup2(stdin_pipe[READ_PIPE], STDIN);
-		close(STDOUT);	dup2(stdout_pipe[WRITE_PIPE], STDOUT);
-		close(STDERR);	dup2(STDOUT, STDERR);
-
-		/* close the pipes we just dup'ed.  The resources will remain.
-		 */
-		close(stdin_pipe[READ_PIPE]);
-		close(stdout_pipe[WRITE_PIPE]);
+		if (stdin_pipe[READ_PIPE] != STDIN) {
+			dup2(stdin_pipe[READ_PIPE], STDIN);
+			close(stdin_pipe[READ_PIPE]);
+		}
+		if (stdout_pipe[WRITE_PIPE] != STDOUT) {
+			close(STDOUT);
+			dup2(stdout_pipe[WRITE_PIPE], STDOUT);
+		}
+		dup2(STDOUT, STDERR);
 
 		/* set our directory, uid and gid.  Set gid first, since once
 		 * we set uid, we've lost root privledges.
@@ -483,6 +484,8 @@ child_process(entry *e, user *u) {
 			      (long)getpid(), children))
 		pid = wait(&waiter);
 		if (pid < OK) {
+			if (errno == EINTR)
+				continue;
 			Debug(DPROC,
 			      ("[%ld] no more grandchildren--mail written?\n",
 			       (long)getpid()))
diff --git a/usr.sbin/cron/pathnames.h b/usr.sbin/cron/pathnames.h
index e01e0321843..ed727d6cf5d 100644
--- a/usr.sbin/cron/pathnames.h
+++ b/usr.sbin/cron/pathnames.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pathnames.h,v 1.3 2001/02/18 19:48:36 millert Exp $	*/
+/*	$OpenBSD: pathnames.h,v 1.4 2001/10/24 17:28:16 millert Exp $	*/
 
 /* Copyright 1993,1994 by Paul Vixie
  * All rights reserved
@@ -82,3 +82,7 @@
 #ifndef _PATH_TMP
 # define _PATH_TMP "/tmp"
 #endif
+
+#ifndef _PATH_DEVNULL
+# define _PATH_DEVNULL "/dev/null"
+#endif
diff --git a/usr.sbin/cron/popen.c b/usr.sbin/cron/popen.c
index bac4b39c765..2e922a11067 100644
--- a/usr.sbin/cron/popen.c
+++ b/usr.sbin/cron/popen.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: popen.c,v 1.11 2001/10/01 19:19:09 millert Exp $	*/
+/*	$OpenBSD: popen.c,v 1.12 2001/10/24 17:28:16 millert Exp $	*/
 
 /*
  * Copyright (c) 1988, 1993, 1994
@@ -38,7 +38,7 @@
 #if 0
 static char sccsid[] = "@(#)popen.c	8.3 (Berkeley) 4/6/94";
 #else
-static char rcsid[] = "$OpenBSD: popen.c,v 1.11 2001/10/01 19:19:09 millert Exp $";
+static char rcsid[] = "$OpenBSD: popen.c,v 1.12 2001/10/24 17:28:16 millert Exp $";
 #endif
 #endif /* not lint */
 
@@ -153,15 +153,15 @@ cron_popen(program, type, e)
 		}
 		closelog();
 		if (*type == 'r') {
-			if (pdes[1] != STDOUT_FILENO) {
-				dup2(pdes[1], STDOUT_FILENO);
+			if (pdes[1] != STDOUT) {
+				dup2(pdes[1], STDOUT);
 				(void)close(pdes[1]);
 			}
-			dup2(STDOUT_FILENO, STDERR_FILENO); /* stderr too! */
+			dup2(STDOUT, STDERR);	/* stderr too! */
 			(void)close(pdes[0]);
 		} else {
-			if (pdes[0] != STDIN_FILENO) {
-				dup2(pdes[0], STDIN_FILENO);
+			if (pdes[0] != STDIN) {
+				dup2(pdes[0], STDIN);
 				(void)close(pdes[0]);
 			}
 			(void)close(pdes[1]);