Initial revision

shared_src/fat.h

@@ -0,0 +1,114 @@
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 1996   Erich Boleyn  <erich@uruk.org>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+
+/*
+ *  Defines for the FAT BIOS Parameter Block (embedded in the first block
+ *  of the partition.
+ */
+
+#define FAT_BPB_SIGNATURE             0x29
+
+/* is checking for this signature thing even valid? */
+#define FAT_BPB_CHECK_SIG(bpb) \
+  (*((unsigned char *) (((int)bpb) + 38)) == FAT_BPB_SIGNATURE)
+
+#define FAT_BPB_NUM_SECTORS(bpb) \
+  ( *((unsigned short *) (((int)bpb) + 19)) ? \
+    *((unsigned short *) (((int)bpb) + 19)) : \
+    *((unsigned long *) (((int)bpb) + 32)) )
+
+#define FAT_BPB_BYTES_PER_SECTOR(bpb) \
+  (*((unsigned short *) (((int)bpb) + 11)))
+#define FAT_BPB_SECT_PER_CLUST(bpb) \
+  (*((unsigned char *) (((int)bpb) + 13)))
+#define FAT_BPB_NUM_FAT(bpb) \
+  (*((unsigned char *) (((int)bpb) + 16)))
+
+#define FAT_BPB_RESERVED_SECTORS(bpb) \
+  (*((unsigned short *) (((int)bpb) + 14)))
+#define FAT_BPB_FAT_SECTORS(bpb) \
+  (*((unsigned short *) (((int)bpb) + 22)))
+#define FAT_BPB_FAT_START(bpb) FAT_BPB_RESERVED_SECTORS(bpb)
+
+/*
+ *  This appears to be a MAJOR kludge!!  Don't use it if possible...
+ */
+#define FAT_BPB_HIDDEN_SECTORS(bpb) \
+  (*((unsigned long *) (((int)bpb) + 28)))
+
+#define FAT_BPB_ROOT_DIR_START(bpb) \
+  ( FAT_BPB_NUM_FAT(bpb) * FAT_BPB_FAT_SECTORS(bpb) \
+    + FAT_BPB_FAT_START(bpb) )
+
+#define FAT_BPB_ROOT_DIR_LENGTH(bpb) \
+  ( (*((unsigned short *) (((int)bpb) + 17)) + 0xF) >> 4 )
+
+#define FAT_BPB_DATA_OFFSET(bpb) \
+  ( FAT_BPB_ROOT_DIR_START(bpb) + FAT_BPB_ROOT_DIR_LENGTH(bpb) )
+
+#define FAT_BPB_NUM_CLUST(bpb) \
+  ( ( FAT_BPB_NUM_SECTORS(bpb) - FAT_BPB_DATA_OFFSET(bpb) ) \
+    / FAT_BPB_SECT_PER_CLUST(bpb) )
+
+/*
+ *  Defines minimum disk size to be considered a FAT partition
+ */
+
+#define FAT_MIN_NUM_SECTORS       720  /* 360 K disk */
+
+/*
+ *  Defines how to differentiate a 12-bit and 16-bit FAT.
+ */
+
+#define FAT_MAX_12BIT_CLUST       4087   /* 4085 + 2 */
+
+#define FAT_BPB_FLOPPY_NUM_SECTORS(bpb) \
+  ( *((unsigned short *) (((int)bpb) + 19)) \
+    && !*((unsigned long *) (((int)bpb) + 32)) \
+    && *((unsigned short *) (((int)bpb) + 19)) >= FAT_MIN_NUM_SECTORS \
+    && ((*((unsigned short *) (((int)bpb) + 19)) - FAT_BPB_DATA_OFFSET(bpb)) \
+	/ FAT_BPB_SECT_PER_CLUST(bpb)) < (FAT_BPB_FAT_SECTORS(bpb) * 342) )
+
+/*
+ *  Defines for the file "attribute" byte
+ */
+
+#define FAT_ATTRIB_OK_MASK        0x37
+#define FAT_ATTRIB_NOT_OK_MASK    0xC8
+#define FAT_ATTRIB_DIR            0x10
+
+
+/*
+ *  Defines for FAT directory entries
+ */
+
+#define FAT_DIRENTRY_LENGTH       32
+
+#define FAT_DIRENTRY_ATTRIB(entry) \
+  (*((unsigned char *) (entry+11)))
+#define FAT_DIRENTRY_VALID(entry) \
+  ( ((*((unsigned char *) entry)) != 0) \
+    & ((*((unsigned char *) entry)) != 0xE5) \
+    & !(FAT_DIRENTRY_ATTRIB(entry) & FAT_ATTRIB_NOT_OK_MASK) )
+#define FAT_DIRENTRY_FIRST_CLUSTER(entry) \
+  (*((unsigned short *) (entry+26)))
+#define FAT_DIRENTRY_FILELENGTH(entry) \
+  (*((unsigned long *) (entry+28)))
+