- Move gets() function to libkern (I want to use it outside vfs_mount.c).

- Add buffer size limitations (overflow will not be possible anymore).
- Add 'visible' option, which will allow for passphrase reading in the
  future.
- Remove special treatment of '@' and '#', those two are only confusing.

Discussed with:	rwatson
MFC after:	2 weeks

sys/conf/files

@@ -1221,6 +1221,7 @@ libkern/bcd.c			standard
 libkern/bsearch.c		standard
 libkern/crc32.c			standard
 libkern/fnmatch.c		standard
+libkern/gets.c			standard
 libkern/iconv.c			optional libiconv
 libkern/iconv_converter_if.m	optional libiconv
 libkern/iconv_xlat.c		optional libiconv

sys/kern/vfs_mount.c

@@ -39,9 +39,9 @@ __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
 #include <sys/conf.h>
-#include <sys/cons.h>
 #include <sys/jail.h>
 #include <sys/kernel.h>
+#include <sys/libkern.h>
 #include <sys/mac.h>
 #include <sys/malloc.h>
 #include <sys/mount.h>
@@ -73,7 +73,6 @@ __FBSDID("$FreeBSD$");
 #define	ROOTNAME		"root_device"
 #define	VFS_MOUNTARG_SIZE_MAX	(1024 * 64)
 
-static void	gets(char *cp);
 static int	vfs_domount(struct thread *td, const char *fstype,
 		    char *fspath, int fsflags, void *fsdata);
 static int	vfs_mount_alloc(struct vnode *dvp, struct vfsconf *vfsp,
@@ -1290,7 +1289,7 @@ vfs_mountroot_ask(void)
 		printf("  ?                  List valid disk boot devices\n");
 		printf("  <empty line>       Abort manual input\n");
 		printf("\nmountroot> ");
-		gets(name);
+		gets(name, sizeof(name), 1);
 		if (name[0] == '\0')
 			return (1);
 		if (name[0] == '?') {
@@ -1303,47 +1302,6 @@ vfs_mountroot_ask(void)
 	}
 }
 
-/*
- * Local helper function for vfs_mountroot_ask.
- */
-static void
-gets(char *cp)
-{
-	char *lp;
-	int c;
-
-	lp = cp;
-	for (;;) {
-		printf("%c", c = cngetc() & 0177);
-		switch (c) {
-		case -1:
-		case '\n':
-		case '\r':
-			*lp++ = '\0';
-			return;
-		case '\b':
-		case '\177':
-			if (lp > cp) {
-				printf(" \b");
-				lp--;
-			}
-			continue;
-		case '#':
-			lp--;
-			if (lp < cp)
-				lp = cp;
-			continue;
-		case '@':
-		case 'u' & 037:
-			lp = cp;
-			printf("%c", '\n');
-			continue;
-		default:
-			*lp++ = c;
-		}
-	}
-}
-
 /*
  * ---------------------------------------------------------------------
  * Functions for querying mount options/arguments from filesystems.

sys/libkern/gets.c

@@ -0,0 +1,67 @@
+/*-
+ * Copyright (c) 1999 Michael Smith
+ * Copyright (c) 2005 Pawel Jakub Dawidek <pjd@FreeBSD.org>
+ * All rights reserved.
+ *
+ * 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.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHORS 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 AUTHORS 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 <sys/param.h>
+#include <sys/cons.h>
+#include <sys/libkern.h>
+
+void
+gets(char *cp, size_t size, int visible)
+{
+	char *lp, *end;
+	int c;
+
+	lp = cp;
+	end = cp + size - 1;
+	for (;;) {
+		c = cngetc() & 0177;
+		switch (c) {
+		case -1:
+		case '\n':
+		case '\r':
+			*lp = '\0';
+			return;
+		case '\b':
+		case '\177':
+			if (lp > cp) {
+				if (visible)
+					printf("%c \b", c);
+				lp--;
+			}
+			continue;
+		default:
+			if (lp < end) {
+				if (visible)
+					printf("%c", c);
+				*lp++ = c;
+			}
+		}
+	}
+}

sys/sys/libkern.h

@@ -83,6 +83,7 @@ int	 fls(int);
 int	 flsl(long);
 #endif
 int	 fnmatch(const char *, const char *, int);
+void	 gets(char *, size_t, int);
 int	 locc(int, char *, u_int);
 void	 qsort(void *base, size_t nmemb, size_t size,
 	    int (*compar)(const void *, const void *));