4 files changed, 129 insertions, 3 deletions

diff --git a/lib/libc/stdio/Makefile.inc b/lib/libc/stdio/Makefile.inc
index 332e7764bc0e..c029a67f17d4 100644
--- a/lib/libc/stdio/Makefile.inc
+++ b/lib/libc/stdio/Makefile.inc
@@ -14,7 +14,7 @@ SRCS+=	_flock_stub.c asprintf.c clrerr.c dprintf.c \
 	fputwc.c fputws.c fread.c freopen.c fscanf.c fseek.c fsetpos.c \
 	ftell.c funopen.c fvwrite.c fwalk.c fwide.c fwprintf.c fwscanf.c \
 	fwrite.c getc.c getchar.c getdelim.c getline.c \
-	gets.c getw.c getwc.c getwchar.c makebuf.c mktemp.c \
+	gets.c gets_s.c getw.c getwc.c getwchar.c makebuf.c mktemp.c \
 	open_memstream.c open_wmemstream.c \
 	perror.c printf.c printf-pos.c putc.c putchar.c \
 	puts.c putw.c putwc.c putwchar.c \
@@ -50,6 +50,7 @@ MLINKS+=ferror.3 ferror_unlocked.3 \
 	ferror.3 fileno.3 ferror.3 fileno_unlocked.3
 MLINKS+=fflush.3 fpurge.3
 MLINKS+=fgets.3 gets.3
+MLINKS+=fgets.3 gets_s.3
 MLINKS+=flockfile.3 ftrylockfile.3 flockfile.3 funlockfile.3
 MLINKS+=fopen.3 fdopen.3 fopen.3 freopen.3 fopen.3 fmemopen.3
 MLINKS+=fputs.3 puts.3
diff --git a/lib/libc/stdio/Symbol.map b/lib/libc/stdio/Symbol.map
index 92aefa0f09b9..25cbb49af316 100644
--- a/lib/libc/stdio/Symbol.map
+++ b/lib/libc/stdio/Symbol.map
@@ -165,6 +165,7 @@ FBSD_1.3 {
 FBSD_1.4 {
 	fdclose;
 	fopencookie;
+	gets_s;
 };
 
 FBSDprivate_1.0 {
diff --git a/lib/libc/stdio/fgets.3 b/lib/libc/stdio/fgets.3
index f64dd9164eb3..755e531b0884 100644
--- a/lib/libc/stdio/fgets.3
+++ b/lib/libc/stdio/fgets.3
@@ -46,6 +46,8 @@
 .Ft char *
 .Fn fgets "char * restrict str" "int size" "FILE * restrict stream"
 .Ft char *
+.Fn gets_s "char *str" "rsize_t size"
+.Ft char *
 .Fn gets "char *str"
 .Sh DESCRIPTION
 The
@@ -65,6 +67,17 @@ If any characters are read and there is no error, a
 character is appended to end the string.
 .Pp
 The
+.Fn gets_s
+function
+is equivalent to
+.Fn fgets
+with a
+.Fa stream
+of
+.Dv stdin ,
+except that the newline character (if any) is not stored in the string.
+.Pp
+The
 .Fn gets
 function
 is equivalent to
@@ -80,7 +93,8 @@ It is the caller's responsibility to ensure that the input line,
 if any, is sufficiently short to fit in the string.
 .Sh RETURN VALUES
 Upon successful completion,
-.Fn fgets
+.Fn fgets ,
+.Fn gets_s ,
 and
 .Fn gets
 return
@@ -94,7 +108,8 @@ they return
 .Dv NULL
 and the buffer contents are indeterminate.
 The
-.Fn fgets
+.Fn fgets ,
+.Fn gets_s ,
 and
 .Fn gets
 functions
@@ -141,6 +156,13 @@ and
 .Fn gets
 conform to
 .St -isoC-99 .
+.Fn gets_s
+conforms to
+.St -isoC-2011
+K.3.7.4.1.
+.Fn gets
+has been removed from
+.St -isoC-2011 .
 .Sh SECURITY CONSIDERATIONS
 The
 .Fn gets
diff --git a/lib/libc/stdio/gets_s.c b/lib/libc/stdio/gets_s.c
new file mode 100644
index 000000000000..ad8134958734
--- /dev/null
+++ b/lib/libc/stdio/gets_s.c
@@ -0,0 +1,102 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1990, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ * Copyright (c) 2017, 2018
+ *	Cyril S. E. Schubert.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Chris Torek.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include "namespace.h"
+#include <errno.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <stdio.h>
+#include "un-namespace.h"
+#include "libc_private.h"
+#include "local.h"
+
+static inline char *
+_gets_s(char *buf, rsize_t n)
+{
+	int c;
+	char *s;
+
+	ORIENT(stdin, -1);
+	for (s = buf, n--; (c = __sgetc(stdin)) != '\n' && n > 0 ; n--) {
+		if (c == EOF) {
+			if (s == buf) {
+				return (NULL);
+			} else
+				break;
+		} else
+			*s++ = c;
+	}
+
+	/*
+ 	 * If end of buffer reached, discard until \n or eof.
+	 * Then throw an error.
+	 */
+	if (n == 0) {
+		/* discard */
+		while ((c = __sgetc(stdin)) != '\n' && c != EOF);
+		/* throw the error after lock released prior to exit */
+		__throw_constraint_handler_s("gets_s : end of buffer", E2BIG);
+		return (NULL);
+	}
+	*s = 0;
+	return (buf);
+}
+
+/* ISO/IEC 9899:2011 K.3.7.4.1 */
+char *
+gets_s(char *buf, rsize_t n)
+{
+	char *ret;
+	if (buf == NULL) {
+		__throw_constraint_handler_s("gets_s : str is NULL", EINVAL);
+		return(NULL);
+	} else if (n > RSIZE_MAX) {
+		__throw_constraint_handler_s("gets_s : n > RSIZE_MAX",
+			EINVAL);
+		return(NULL);
+	} else if (n == 0) {
+		__throw_constraint_handler_s("gets_s : n == 0", EINVAL);
+		return(NULL);
+	}
+
+	FLOCKFILE_CANCELSAFE(stdin);
+	ret = _gets_s(buf, n);
+	FUNLOCKFILE_CANCELSAFE();
+	return (ret);
+}