cron: log when a crontab path is too long

Log via syslog when snprintf truncates the crontab path, instead of
silently skipping the entry.

Signed-off-by:	Christos Longros <chris.longros@gmail.com>
Reviewed by:	bcr, kevans
Differential Revision:	https://reviews.freebsd.org/D56235

usr.sbin/cron/cron/cron.8

@@ -19,7 +19,7 @@
 .\"
 .\" $Id: cron.8,v 1.2 1998/08/14 00:32:36 vixie Exp $
 .\"
-.Dd January 20, 2026
+.Dd April 29, 2026
 .Dt CRON 8
 .Os
 .Sh NAME
@@ -227,7 +227,14 @@ configuration file for
 .It Pa /usr/local/etc/cron.d
 Directory for third-party package provided crontab files.
 .It Pa /var/cron/tabs
-Directory for personal crontab files
+Directory for personal crontab files.
+Internally the daemon constructs the relative path
+.Pa tabs/ Ns Ar filename ,
+which must fit within
+.Dv MAXNAMLEN
+bytes; in practice this allows filenames up to 250 bytes.
+Longer entries are skipped and a diagnostic is logged via
+.Xr syslog 3 .
 .El
 .Sh SEE ALSO
 .Xr crontab 1 ,

usr.sbin/cron/cron/database.c

@@ -166,8 +166,10 @@ load_database(cron_db *old_db)
 		fname[sizeof(fname)-1] = '\0';
 
 		if (snprintf(tabname, sizeof tabname, CRON_TAB(fname))
-		    >= sizeof(tabname))
-			continue;	/* XXX log? */
+		    >= (int)sizeof(tabname)) {
+			log_it("CRON", getpid(), "TABNAME TOO LONG", fname);
+			continue;
+		}
 
 		process_crontab(fname, fname, tabname,
 				&statbuf, &new_db, old_db);