MFC r275680:

Add fstyp(8).  This utility, named after its SVR4 counterpart, detects
filesystems.  It differs from file(1) in that it gives machine-parseable
output, it outputs filesystem labels, doesn't get confused by other
formats metadata, and runs in Capsicum sandbox.

Differential Revision:	https://reviews.freebsd.org/D1255
Relnotes:	yes
Sponsored by:	The FreeBSD Foundation

1 files changed, 90 insertions, 0 deletions

diff --git a/usr.sbin/fstyp/ext2fs.c b/usr.sbin/fstyp/ext2fs.c
new file mode 100644
index 0000000..df9e66e
--- /dev/null
+++ b/usr.sbin/fstyp/ext2fs.c
@@ -0,0 +1,90 @@
+/*-
+ * Copyright (c) 2005 Stanislav Sedov
+ * Copyright (c) 2014 The FreeBSD Foundation
+ * All rights reserved.
+ *
+ * This software was developed by Edward Tomasz Napierala under sponsorship
+ * from the FreeBSD Foundation.
+ *
+ * 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 AUTHOR 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 AUTHOR 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 <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "fstyp.h"
+
+#define EXT2FS_SB_OFFSET	1024
+#define EXT2_SUPER_MAGIC	0xef53
+#define EXT2_DYNAMIC_REV	1
+
+typedef struct e2sb {
+	uint8_t		fake1[56];
+	uint16_t	s_magic;
+	uint8_t		fake2[18];
+	uint32_t	s_rev_level;
+	uint8_t		fake3[40];
+	char		s_volume_name[16];
+} e2sb_t;
+
+int
+fstyp_ext2fs(FILE *fp, char *label, size_t size)
+{
+	e2sb_t *fs;
+	char *s_volume_name;
+
+	fs = (e2sb_t *)read_buf(fp, EXT2FS_SB_OFFSET, 512);
+	if (fs == NULL)
+		return (1);
+
+	/* Check for magic and versio n*/
+	if (fs->s_magic == EXT2_SUPER_MAGIC &&
+	    fs->s_rev_level == EXT2_DYNAMIC_REV) {
+		//G_LABEL_DEBUG(1, "ext2fs file system detected on %s.",
+		//    pp->name);
+	} else {
+		free(fs);
+		return (1);
+	}
+
+	s_volume_name = fs->s_volume_name;
+	/* Terminate label */
+	s_volume_name[sizeof(fs->s_volume_name) - 1] = '\0';
+
+	if (s_volume_name[0] == '/')
+		s_volume_name += 1;
+
+	/* Check for volume label */
+	if (s_volume_name[0] == '\0') {
+		free(fs);
+		return (1);
+	}
+
+	strlcpy(label, s_volume_name, size);
+
+	return (0);
+}