From: Christian Kastner <ckk@kvr.at>
Date: Fri, 15 Jan 2016 21:47:32 +0100
Subject: Prompt on crontab deletion
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Add an option -i that modifies the -r option to prompt the user for a y/n
response before actually deleting the crontab.

Contributed by Javier Fernández-Sanguino Peña <jfs@debian.org>.

Bug-Debian: https://bugs.debian.org/513379
Forwarded: no
Last-Update: 2016-01-15
---
 crontab.1 |  6 +++++-
 crontab.c | 40 ++++++++++++++++++++++++++++++++++++++--
 2 files changed, 43 insertions(+), 3 deletions(-)

diff --git a/crontab.1 b/crontab.1
index f432097..199bae8 100644
--- a/crontab.1
+++ b/crontab.1
@@ -24,7 +24,7 @@ crontab \- maintain crontab files for individual users (Vixie Cron)
 .SH SYNOPSIS
 crontab [ \-u user ] file
 .br
-crontab [ \-u user ] [ \-e ] { \-l | \-r }
+crontab [ \-u user ] [ \-i ] { \-e | \-l | \-r }
 .SH DESCRIPTION
 .I crontab
 is the program used to install, deinstall or list the tables
@@ -100,6 +100,10 @@ from the editor, the modified crontab will be installed automatically.  If
 neither of the environment variables is defined, then the
 default editor /usr/bin/editor is used.
 .PP
+The
+.I \-i
+option modifies the \-r option to prompt the user for a 'y/Y' response
+before actually removing the crontab.
 .SH DEBIAN SPECIFIC
 The "out-of-the-box" behaviour for
 .I crontab \-l
diff --git a/crontab.c b/crontab.c
index 033d536..c48900c 100644
--- a/crontab.c
+++ b/crontab.c
@@ -59,6 +59,7 @@ static	char		Filename[MAX_FNAME];
 static	char		Directory[MAX_FNAME];
 static	FILE		*NewCrontab = NULL;
 static	int		CheckErrorCount;
+static	int		PromptOnDelete;
 static	enum opt_t	Option;
 static	struct passwd	*pw;
 static	void		list_cmd __P((void)),
@@ -80,11 +81,12 @@ usage(msg)
 {
 	fprintf(stderr, "%s: usage error: %s\n", ProgramName, msg);
 	fprintf(stderr, "usage:\t%s [-u user] file\n", ProgramName);
-	fprintf(stderr, "\t%s [-u user] { -e | -l | -r }\n", ProgramName);
+	fprintf(stderr, "\t%s [ -u user ] [ -i ] { -e | -l | -r }\n", ProgramName);
 	fprintf(stderr, "\t\t(default operation is replace, per 1003.2)\n");
 	fprintf(stderr, "\t-e\t(edit user's crontab)\n");
 	fprintf(stderr, "\t-l\t(list user's crontab)\n");
 	fprintf(stderr, "\t-r\t(delete user's crontab)\n");
+	fprintf(stderr, "\t-i\t(prompt before deleting user's crontab)\n");
 	exit(ERROR_EXIT);
 }
 
@@ -176,6 +178,7 @@ parse_args(argc, argv)
 	}
 	Filename[0] = '\0';
 	Option = opt_unknown;
+	PromptOnDelete = 0;
 
 	while (EOF != (argch = getopt(argc, argv, getoptarg))) {
 		switch (argch) {
@@ -220,6 +223,9 @@ parse_args(argc, argv)
 				usage("only one operation permitted");
 			Option = opt_edit;
 			break;
+		case 'i':
+			PromptOnDelete = 1;
+			break;
 		default:
 			usage("unrecognized option");
 		}
@@ -345,9 +351,39 @@ list_cmd() {
 static void
 delete_cmd() {
 	char	n[MAX_FNAME];
+	char	q[MAX_TEMPSTR];
+	int	ans;
+	struct stat fsbuf;
 
-	log_it(RealUser, Pid, "DELETE", User);
+	/* Check if the user has a crontab file first */
 	(void) snprintf(n, MAX_FNAME, CRON_TAB(User));
+	if (stat(n, &fsbuf) < 0) {
+		fprintf(stderr, "no crontab for %s\n", User);
+		exit(ERROR_EXIT);
+	}
+
+	if (PromptOnDelete == 1) {
+		printf("crontab: really delete %s's crontab? (y/n) ", User);
+		fflush(stdout);
+		ans = 0;
+		q[0] = '\0';
+		while ( ans == 0 ) {
+			(void) fgets(q, sizeof q, stdin);
+			switch (islower(q[0]) ? q[0] : tolower(q[0])) {
+			case 'y':
+			case 'n':
+				ans = 1;
+				break;
+			default:
+				fprintf(stderr, "Please enter Y or N: ");
+			}
+		}
+		if ((q[0] == 'N') || (q[0] == 'n')) {
+			exit(OK_EXIT);
+		}
+	}
+
+	log_it(RealUser, Pid, "DELETE", User);
 	if (unlink(n)) {
 		if (errno == ENOENT)
 			fprintf(stderr, "no crontab for %s\n", User);