From af268aa7bb1b97002fc523f0f0e0ca355c50a380 Mon Sep 17 00:00:00 2001
From: Alan Cox <alan@linux.intel.com>
Date: Mon, 8 Jun 2015 20:32:56 +0100
Subject: [PATCH] gets: correct behaviour of gets_s

---
 Library/libs/gets.c | 102 ++++++++++++++++++++++++++------------------
 1 file changed, 60 insertions(+), 42 deletions(-)

diff --git a/Library/libs/gets.c b/Library/libs/gets.c
index 52308e60..b261fb20 100644
--- a/Library/libs/gets.c
+++ b/Library/libs/gets.c
@@ -1,42 +1,60 @@
-/* stdio.c
- * Copyright (C) 1996 Robert de Bath <rdebath@cix.compulink.co.uk>
- * This file is part of the Linux-8086 C library and is distributed
- * under the GNU Library General Public License.
- */  
-    
-/* This is an implementation of the C standard IO package. */ 
-    
-#include "stdio-l.h"
-
-char *gets(char *str) /* BAD function; DON'T use it! */ 
-{
-	/* Auwlright it will work but of course _your_ program will crash */ 
-	/* if it's given a too long line */ 
-	register int c;
-	register char *p = str;
-
-	while (((c = getc(stdin)) != EOF) && (c != '\n'))
-		*p++ = c;
-	*p = '\0';
-	return (((c == EOF) && (p == str)) ? NULL : str);/* NULL == EOF */
-}
-
-char *gets_s(char *str,size_t maxlen)
-{
-	register int c;
-	register char *p=str;
-
-	while ( (((c = getc(stdin)) != EOF) && (c != '\n')) && ( p - str < maxlen) )
-		*p++=c;
-	*p='\0';
-	return (((c == EOF) && (p == str)) ? NULL : str);/* NULL == EOF */
-}
-
-int puts(const void *str) 
-{
-	register int n;
-	if (((n = fputs(str, stdout)) == EOF) 
-	       ||(putc('\n', stdout) == EOF))
-		return (EOF);
-	return (++n);
-}
+/* stdio.c
+ * Copyright (C) 1996 Robert de Bath <rdebath@cix.compulink.co.uk>
+ * This file is part of the Linux-8086 C library and is distributed
+ * under the GNU Library General Public License.
+ */
+
+/* This is an implementation of the C standard IO package. */
+
+#include "stdio-l.h"
+#include <errno.h>
+
+char *gets(char *str)
+{				/* BAD function; DON'T use it! */
+	/* Auwlright it will work but of course _your_ program will crash */
+	/* if it's given a too long line */
+	register int c;
+	register char *p = str;
+
+	while (((c = getc(stdin)) != EOF) && (c != '\n'))
+		*p++ = c;
+	*p = '\0';
+	return (((c == EOF) && (p == str)) ? NULL : str);	/* NULL == EOF */
+}
+
+char *gets_s(char *str, size_t maxlen)
+{
+	register int c;
+	register char *p = str;
+	char *end = p + maxlen - 1;
+	uint8_t over = 0;
+
+	/* NULL is defined as an error so we don't need to consume data */
+	if (str == NULL || maxlen == 0)
+		goto fail;
+
+	while (((c = getc(stdin)) != EOF) && (c != '\n')) {
+		/* < because we need space for the \0 */
+		if (p < end)
+			*p++ = c;
+		else
+			over = 1;
+	}
+	*p = '\0';
+
+	/* NULL == EOF */
+	if (!over)
+		return (((c == EOF) && (p == str)) ? NULL : str);
+fail:
+	errno = ERANGE;
+	return NULL;
+}
+
+int puts(const void *str)
+{
+	register int n;
+	if (((n = fputs(str, stdout)) == EOF)
+	    || (putc('\n', stdout) == EOF))
+		return (EOF);
+	return (++n);
+}
-- 
2.34.1