From 3de5bf61060634c5c8c3a0d231e8a7246094a2c2 Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso@mit.edu>
Date: Tue, 22 Jul 2003 01:06:36 -0400
Subject: [PATCH] probe.c (probe_udf): Add specific UDF probing code, and probe
 	UDF before checking for ISO9660 filesystems.

---
 lib/blkid/ChangeLog |  5 +++++
 lib/blkid/probe.c   | 58 ++++++++++++++++++++++++++++++++++++++++++++++-------
 lib/blkid/probe.h   |  8 ++++++++
 3 files changed, 64 insertions(+), 7 deletions(-)

diff --git a/lib/blkid/ChangeLog b/lib/blkid/ChangeLog
index 2d01b91..0a4e790 100644
--- a/lib/blkid/ChangeLog
+++ b/lib/blkid/ChangeLog
@@ -1,3 +1,8 @@
+2003-07-22  Theodore Ts'o  <tytso@mit.edu>
+
+	* probe.c (probe_udf): Add specific UDF probing code, and probe
+		UDF before checking for ISO9660 filesystems.
+
 2003-07-21  Theodore Ts'o  <tytso@mit.edu>
 
 	* probe.c (blkid_known_fstype): New function which returns true if
diff --git a/lib/blkid/probe.c b/lib/blkid/probe.c
index 2421fff..505400c 100644
--- a/lib/blkid/probe.c
+++ b/lib/blkid/probe.c
@@ -244,6 +244,50 @@ static int probe_romfs(int fd, blkid_cache cache, blkid_dev dev,
 	return 0;
 }
 
+static char
+*udf_magic[] = { "BEA01", "BOOT2", "CD001", "CDW02", "NSR02",
+		 "NSR03", "TEA01", 0 };
+
+static int probe_udf(int fd, blkid_cache cache, blkid_dev dev,
+		       struct blkid_magic *id, unsigned char *buf)
+{
+	int j, bs;
+	struct iso_volume_descriptor isosb;
+	char **m;
+
+	/* determine the block size by scanning in 2K increments
+	   (block sizes larger than 2K will be null padded) */
+	for (bs = 1; bs < 16; bs++) {
+		lseek(fd, bs*2048+32768, SEEK_SET);
+		if (read(fd, (char *)&isosb, sizeof(isosb)) != sizeof(isosb))
+			return 1;
+		if (isosb.id[0])
+			break;
+	}
+
+	/* Scan up to another 64 blocks looking for additional VSD's */
+	for (j = 1; j < 64; j++) {
+		if (j > 1) {
+			lseek(fd, j*bs*2048+32768, SEEK_SET);
+			if (read(fd, (char *)&isosb, sizeof(isosb))
+			    != sizeof(isosb))
+				return 1;
+		}
+		/* If we find NSR0x then call it udf:
+		   NSR01 for UDF 1.00
+		   NSR02 for UDF 1.50
+		   NSR03 for UDF 2.00 */
+		if (!strncmp(isosb.id, "NSR0", 4))
+			return 0;
+		for (m = udf_magic; *m; m++)
+			if (!strncmp(*m, isosb.id, 5))
+				break;
+		if (*m == 0)
+			return 1;
+	}
+	return 1;
+}
+
 /*
  * BLKID_BLK_OFFS is at least as large as the highest bim_kboff defined
  * in the type_array table below + bim_kbalign.
@@ -283,15 +327,15 @@ static struct blkid_magic type_array[] = {
   { "bfs",	 0,	 0,  4, "\316\372\173\033",	0 },
   { "cramfs",	 0,	 0,  4, "E=\315\034",		0 },
   { "qnx4",	 0,	 4,  6, "QNX4FS",		0 },
+  { "udf",	32,	 1,  5, "BEA01",		probe_udf },
+  { "udf",	32,	 1,  5, "BOOT2",		probe_udf },
+  { "udf",	32,	 1,  5, "CD001",		probe_udf },
+  { "udf",	32,	 1,  5, "CDW02",		probe_udf },
+  { "udf",	32,	 1,  5, "NSR02",		probe_udf },
+  { "udf",	32,	 1,  5, "NSR03",		probe_udf },
+  { "udf",	32,	 1,  5, "TEA01",		probe_udf },
   { "iso9660",	32,	 1,  5, "CD001",		0 },
   { "iso9660",	32,	 9,  5, "CDROM",		0 },
-  { "udf",	32,	 1,  5, "BEA01",		0 },
-  { "udf",	32,	 1,  5, "BOOT2",		0 },
-  { "udf",	32,	 1,  5, "CD001",		0 },
-  { "udf",	32,	 1,  5, "CDW02",		0 },
-  { "udf",	32,	 1,  5, "NSR02",		0 },
-  { "udf",	32,	 1,  5, "NSR03",		0 },
-  { "udf",	32,	 1,  5, "TEA01",		0 },
   { "jfs",	32,	 0,  4, "JFS1",			probe_jfs },
   { "hfs",	 1,	 0,  2, "BD",			0 },
   { "ufs",	 8,  0x55c,  4, "T\031\001\000",	0 },
diff --git a/lib/blkid/probe.h b/lib/blkid/probe.h
index 8ab8d72..d418aef 100644
--- a/lib/blkid/probe.h
+++ b/lib/blkid/probe.h
@@ -209,6 +209,14 @@ struct hfs_super_block {
 	__u32	h_blksize;
 };
 
+#define ISODCL(from, to) (to - from + 1)
+struct iso_volume_descriptor {
+	char type[ISODCL(1,1)]; /* 711 */
+	char id[ISODCL(2,6)];
+	char version[ISODCL(7,7)];
+	char data[ISODCL(8,2048)];
+};
+
 /*
  * Byte swap functions
  */
-- 
1.8.3.1