WebSVN – HelenOS – Diff – /trunk/tools/mkfat.py

 #!/usr/bin/env python
+#
 # Copyright (c) 2008 Martin Decky
 # All rights reserved.
+#
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions
 # are met:
+#
 # - Redistributions of source code must retain the above copyright
 #   notice, this list of conditions and the following disclaimer.
 # - 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.
 # - The name of the author may not be used to endorse or promote products
 #   derived from this software without specific prior written permission.
+#
 # THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.
+#
 """
 FAT creator
 """
 import sys
 import os
 import random
 import xstruct
+def align_up(size, alignment):
+    "Return size aligned up to alignment"
+    if (size % alignment == 0):
+        return size
+    return (((size / alignment) + 1) * alignment)
+def subtree_size(root, cluster_size):
+    "Recursive directory walk and calculate size"
+    size = 0
+    files = 0
+    for name in os.listdir(root):
+        canon = os.path.join(root, name)
+        if (os.path.isfile(canon)):
+            size += align_up(os.path.getsize(canon), cluster_size)
+            files += 1
+        if (os.path.isdir(canon)):
+            size += subtree_size(canon, cluster_size)
+            files += 1
+    return size + align_up(files * 32, cluster_size)
+def root_entries(root):
+    "Return number of root directory entries"
+    return len(os.listdir(root))
 BOOT_SECTOR = """little:
     uint8_t jmp[3]             /* jump instruction */
     char oem[8]                /* OEM string */
     uint16_t sector            /* bytes per sector */
     uint8_t cluster            /* sectors per cluster */
     uint16_t reserved          /* reserved sectors */
     uint8_t fats               /* number of FATs */
     uint16_t rootdir           /* root directory entries */
     uint16_t sectors           /* total number of sectors */
     uint8_t descriptor         /* media descriptor */
     uint16_t fat_sectors       /* sectors per single FAT */
     uint16_t track_sectors     /* sectors per track */
     uint16_t heads             /* number of heads */
     uint32_t hidden            /* hidden sectors */
     uint32_t sectors_big       /* total number of sectors (if sectors == 0) */
     /* Extended BIOS Parameter Block */
     uint8_t drive              /* physical drive number */
     padding[1]                 /* reserved (current head) */
     uint8_t extboot_signature  /* extended boot signature */
     uint32_t serial            /* serial number */
     char label[11]             /* volume label */
     char fstype[8]             /* filesystem type */
     padding[448]               /* boot code */
     uint8_t boot_signature[2]  /* boot signature */
 """
 def usage(prname):
     "Print usage syntax"
     print prname + " <PATH> <IMAGE>"
 def main():
     if (len(sys.argv) < 3):
         usage(sys.argv[0])
         return
     path = os.path.abspath(sys.argv[1])
     if (not os.path.isdir(path)):
         print "<PATH> must be a directory"
         return
+    sector_size = 512
+    cluster_size = 4096
+    root_size = align_up(root_entries(sys.argv[1]) * 32, sector_size)
+    size = subtree_size(sys.argv[1], cluster_size)
+    fat_size = align_up(size / cluster_size * 2, sector_size)
+    sectors = (cluster_size + 2 * fat_size + root_size + size) / sector_size
     outf = file(sys.argv[2], "w")
     boot_sector = xstruct.create(BOOT_SECTOR)
     boot_sector.jmp = [0xEB, 0x3C, 0x90]
     boot_sector.oem = "MSDOS5.0"
-    boot_sector.sector = 512
+    boot_sector.sector = sector_size
-    boot_sector.cluster = 8 # 4096 bytes per cluster
+    boot_sector.cluster = cluster_size / sector_size
-    boot_sector.reserved = 1
+    boot_sector.reserved = cluster_size / sector_size
     boot_sector.fats = 2
-    boot_sector.rootdir = 224 # FIXME: root directory should be sector aligned
+    boot_sector.rootdir = root_size / 32
-    boot_sector.sectors = 0 # FIXME
+    boot_sector.sectors = (sectors if (sectors <= 65535) else 0)
     boot_sector.descriptor = 0xF8
-    boot_sector.fat_sectors = 0 # FIXME
+    boot_sector.fat_sectors = fat_size / sector_size
-    boot_sector.track_sectors = 0 # FIXME
+    boot_sector.track_sectors = 63
-    boot_sector.heads = 0 # FIXME
+    boot_sector.heads = 6
     boot_sector.hidden = 0
-    boot_sector.sectors_big = 0 # FIXME
+    boot_sector.sectors_big = (sectors if (sectors > 65535) else 0)
-    boot_sector.drive = 0
+    boot_sector.drive = 0x80
     boot_sector.extboot_signature = 0x29
     boot_sector.serial = random.randint(0, 0xFFFFFFFF)
     boot_sector.label = "HELENOS"
     boot_sector.fstype = "FAT16   "
     boot_sector.boot_signature = [0x55, 0xAA]
     outf.write(boot_sector.pack())
     outf.close()
 if __name__ == '__main__':
     main()

Subversion Repositories HelenOS

(root)/trunk/tools/mkfat.py – Rev 3264 → 3509