Add a 'force' option for non-interactive crontab removal

Add a '-f' option to force crontab '-r' to be non-interactive.

Submitted by:	Sam Gwydir <sam at samgwydir.com>
Reviewed by:	me, wblock (previous version)
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D8815

2 files changed, 15 insertions, 5 deletions

diff --git a/usr.sbin/cron/crontab/crontab.1 b/usr.sbin/cron/crontab/crontab.1
index 0183c39bdfa3..f4792bf78cc4 100644
--- a/usr.sbin/cron/crontab/crontab.1
+++ b/usr.sbin/cron/crontab/crontab.1
@@ -17,7 +17,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd May 13, 2010
+.Dd December 20, 2016
 .Dt CRONTAB 1
 .Os
 .Sh NAME
@@ -31,7 +31,8 @@
 .Op Fl u Ar user
 {
 .Fl l |
-.Fl r |
+.Fl r Op Fl f
+|
 .Fl e
 }
 .Sh DESCRIPTION
@@ -97,6 +98,11 @@ option for safety's sake.
 Display the current crontab on standard output.
 .It Fl r
 Remove the current crontab.
+By default the
+.Fl r
+option prompts for confirmation, adding the
+.Fl f
+option will attempt to remove the current crontab without confirmation.
 .It Fl e
 Edit the current crontab using the editor specified by
 the
diff --git a/usr.sbin/cron/crontab/crontab.c b/usr.sbin/cron/crontab/crontab.c
index 933450b9b4d5..53c58403406a 100644
--- a/usr.sbin/cron/crontab/crontab.c
+++ b/usr.sbin/cron/crontab/crontab.c
@@ -63,6 +63,7 @@ static	char		Filename[MAX_FNAME];
 static	FILE		*NewCrontab;
 static	int		CheckErrorCount;
 static	enum opt_t	Option;
+static	int		fflag;
 static	struct passwd	*pw;
 static	void		list_cmd(void),
 			delete_cmd(void),
@@ -79,7 +80,7 @@ usage(char *msg)
 	fprintf(stderr, "crontab: usage error: %s\n", msg);
 	fprintf(stderr, "%s\n%s\n",
 		"usage: crontab [-u user] file",
-		"       crontab [-u user] { -e | -l | -r }");
+		"       crontab [-u user] { -l | -r [-f] | -e }");
 	exit(ERROR_EXIT);
 }
 
@@ -142,7 +143,7 @@ parse_args(argc, argv)
 	strcpy(RealUser, User);
 	Filename[0] = '\0';
 	Option = opt_unknown;
-	while ((argch = getopt(argc, argv, "u:lerx:")) != -1) {
+	while ((argch = getopt(argc, argv, "u:lerx:f")) != -1) {
 		switch (argch) {
 		case 'x':
 			if (!set_debug_flags(optarg))
@@ -172,6 +173,9 @@ parse_args(argc, argv)
 				usage("only one operation permitted");
 			Option = opt_edit;
 			break;
+		case 'f':
+			fflag = 1;
+			break;
 		default:
 			usage("unrecognized option");
 		}
@@ -282,7 +286,7 @@ delete_cmd() {
 	char	n[MAX_FNAME];
 	int ch, first;
 
-	if (isatty(STDIN_FILENO)) {
+	if (!fflag && isatty(STDIN_FILENO)) {
 		(void)fprintf(stderr, "remove crontab for %s? ", User);
 		first = ch = getchar();
 		while (ch != '\n' && ch != EOF)