source: mainline/tools/mkfat.py@ 4e9aaf5

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 4e9aaf5 was 3c80f2b, checked in by Martin Decky <martin@…>, 15 years ago

Python coding style cleanup (no change in functionality)
  • Property mode set to 100755
File size: 13.0 KB
Line 
1#!/usr/bin/env python
2#
3# Copyright (c) 2008 Martin Decky
4# All rights reserved.
5#
6# Redistribution and use in source and binary forms, with or without
7# modification, are permitted provided that the following conditions
8# are met:
9#
10# - Redistributions of source code must retain the above copyright
11# notice, this list of conditions and the following disclaimer.
12# - Redistributions in binary form must reproduce the above copyright
13# notice, this list of conditions and the following disclaimer in the
14# documentation and/or other materials provided with the distribution.
15# - The name of the author may not be used to endorse or promote products
16# derived from this software without specific prior written permission.
17#
18# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28#
29
30"""
31FAT creator
32"""
33
34import sys
35import os
36import random
37import xstruct
38import array
39
40exclude_names = set(['.svn', '.bzr'])
41
42def align_up(size, alignment):
43 "Return size aligned up to alignment"
44
45 if (size % alignment == 0):
46 return size
47
48 return (((size / alignment) + 1) * alignment)
49
50def subtree_size(root, cluster_size, dirent_size):
51 "Recursive directory walk and calculate size"
52
53 size = 0
54 files = 2
55
56 for name in os.listdir(root):
57 canon = os.path.join(root, name)
58
59 if (os.path.isfile(canon) and (not name in exclude_names)):
60 size += align_up(os.path.getsize(canon), cluster_size)
61 files += 1
62
63 if (os.path.isdir(canon) and (not name in exclude_names)):
64 size += subtree_size(canon, cluster_size, dirent_size)
65 files += 1
66
67 return size + align_up(files * dirent_size, cluster_size)
68
69def root_entries(root):
70 "Return number of root directory entries"
71
72 return len(os.listdir(root))
73
74def write_file(path, outf, cluster_size, data_start, fat, reserved_clusters):
75 "Store the contents of a file"
76
77 size = os.path.getsize(path)
78 prev = -1
79 first = 0
80
81 inf = file(path, "r")
82 rd = 0;
83 while (rd < size):
84 empty_cluster = fat.index(0)
85 fat[empty_cluster] = 0xffff
86
87 if (prev != -1):
88 fat[prev] = empty_cluster
89 else:
90 first = empty_cluster
91
92 prev = empty_cluster
93
94 data = inf.read(cluster_size);
95 outf.seek(data_start + (empty_cluster - reserved_clusters) * cluster_size)
96 outf.write(data)
97 rd += len(data)
98 inf.close()
99
100 return first, size
101
102def write_directory(directory, outf, cluster_size, data_start, fat, reserved_clusters, dirent_size, empty_cluster):
103 "Store the contents of a directory"
104
105 length = len(directory)
106 size = length * dirent_size
107 prev = -1
108 first = 0
109
110 i = 0
111 rd = 0;
112 while (rd < size):
113 if (prev != -1):
114 empty_cluster = fat.index(0)
115 fat[empty_cluster] = 0xffff
116 fat[prev] = empty_cluster
117 else:
118 first = empty_cluster
119
120 prev = empty_cluster
121
122 data = ''
123 data_len = 0
124 while ((i < length) and (data_len < cluster_size)):
125 if (i == 0):
126 directory[i].cluster = empty_cluster
127
128 data += directory[i].pack()
129 data_len += dirent_size
130 i += 1
131
132 outf.seek(data_start + (empty_cluster - reserved_clusters) * cluster_size)
133 outf.write(data)
134 rd += len(data)
135
136 return first, size
137
138DIR_ENTRY = """little:
139 char name[8] /* file name */
140 char ext[3] /* file extension */
141 uint8_t attr /* file attributes */
142 uint8_t lcase /* file name case (NT extension) */
143 uint8_t ctime_fine /* create time (fine resolution) */
144 uint16_t ctime /* create time */
145 uint16_t cdate /* create date */
146 uint16_t adate /* access date */
147 padding[2] /* EA-index */
148 uint16_t mtime /* modification time */
149 uint16_t mdate /* modification date */
150 uint16_t cluster /* first cluster */
151 uint32_t size /* file size */
152"""
153
154DOT_DIR_ENTRY = """little:
155 uint8_t signature /* 0x2e signature */
156 char name[7] /* empty */
157 char ext[3] /* empty */
158 uint8_t attr /* file attributes */
159 padding[1] /* reserved for NT */
160 uint8_t ctime_fine /* create time (fine resolution) */
161 uint16_t ctime /* create time */
162 uint16_t cdate /* create date */
163 uint16_t adate /* access date */
164 padding[2] /* EA-index */
165 uint16_t mtime /* modification time */
166 uint16_t mdate /* modification date */
167 uint16_t cluster /* first cluster */
168 uint32_t size /* file size */
169"""
170
171DOTDOT_DIR_ENTRY = """little:
172 uint8_t signature[2] /* 0x2e signature */
173 char name[6] /* empty */
174 char ext[3] /* empty */
175 uint8_t attr /* file attributes */
176 padding[1] /* reserved for NT */
177 uint8_t ctime_fine /* create time (fine resolution) */
178 uint16_t ctime /* create time */
179 uint16_t cdate /* create date */
180 uint16_t adate /* access date */
181 padding[2] /* EA-index */
182 uint16_t mtime /* modification time */
183 uint16_t mdate /* modification date */
184 uint16_t cluster /* first cluster */
185 uint32_t size /* file size */
186"""
187
188def mangle_fname(name):
189 # FIXME: filter illegal characters
190 parts = name.split('.')
191
192 if (len(parts) > 0):
193 fname = parts[0]
194 else:
195 fname = ''
196
197 return (fname + ' ').upper()[0:8]
198
199def mangle_ext(name):
200 # FIXME: filter illegal characters
201 parts = name.split('.')
202
203 if (len(parts) > 1):
204 ext = parts[1]
205 else:
206 ext = ''
207
208 return (ext + ' ').upper()[0:3]
209
210def create_dirent(name, directory, cluster, size):
211 dir_entry = xstruct.create(DIR_ENTRY)
212
213 dir_entry.name = mangle_fname(name)
214 dir_entry.ext = mangle_ext(name)
215
216 if (directory):
217 dir_entry.attr = 0x30
218 else:
219 dir_entry.attr = 0x20
220
221 dir_entry.lcase = 0x18
222 dir_entry.ctime_fine = 0 # FIXME
223 dir_entry.ctime = 0 # FIXME
224 dir_entry.cdate = 0 # FIXME
225 dir_entry.adate = 0 # FIXME
226 dir_entry.mtime = 0 # FIXME
227 dir_entry.mdate = 0 # FIXME
228 dir_entry.cluster = cluster
229
230 if (directory):
231 dir_entry.size = 0
232 else:
233 dir_entry.size = size
234
235 return dir_entry
236
237def create_dot_dirent(empty_cluster):
238 dir_entry = xstruct.create(DOT_DIR_ENTRY)
239
240 dir_entry.signature = 0x2e
241 dir_entry.name = ' '
242 dir_entry.ext = ' '
243 dir_entry.attr = 0x10
244
245 dir_entry.ctime_fine = 0 # FIXME
246 dir_entry.ctime = 0 # FIXME
247 dir_entry.cdate = 0 # FIXME
248 dir_entry.adate = 0 # FIXME
249 dir_entry.mtime = 0 # FIXME
250 dir_entry.mdate = 0 # FIXME
251 dir_entry.cluster = empty_cluster
252 dir_entry.size = 0
253
254 return dir_entry
255
256def create_dotdot_dirent(parent_cluster):
257 dir_entry = xstruct.create(DOTDOT_DIR_ENTRY)
258
259 dir_entry.signature = [0x2e, 0x2e]
260 dir_entry.name = ' '
261 dir_entry.ext = ' '
262 dir_entry.attr = 0x10
263
264 dir_entry.ctime_fine = 0 # FIXME
265 dir_entry.ctime = 0 # FIXME
266 dir_entry.cdate = 0 # FIXME
267 dir_entry.adate = 0 # FIXME
268 dir_entry.mtime = 0 # FIXME
269 dir_entry.mdate = 0 # FIXME
270 dir_entry.cluster = parent_cluster
271 dir_entry.size = 0
272
273 return dir_entry
274
275def recursion(head, root, outf, cluster_size, root_start, data_start, fat, reserved_clusters, dirent_size, parent_cluster):
276 "Recursive directory walk"
277
278 directory = []
279
280 if (not head):
281 # Directory cluster preallocation
282 empty_cluster = fat.index(0)
283 fat[empty_cluster] = 0xffff
284
285 directory.append(create_dot_dirent(empty_cluster))
286 directory.append(create_dotdot_dirent(parent_cluster))
287 else:
288 empty_cluster = 0
289
290 for name in os.listdir(root):
291 canon = os.path.join(root, name)
292
293 if (os.path.isfile(canon) and (not name in exclude_names)):
294 rv = write_file(canon, outf, cluster_size, data_start, fat, reserved_clusters)
295 directory.append(create_dirent(name, False, rv[0], rv[1]))
296
297 if (os.path.isdir(canon) and (not name in exclude_names)):
298 rv = recursion(False, canon, outf, cluster_size, root_start, data_start, fat, reserved_clusters, dirent_size, empty_cluster)
299 directory.append(create_dirent(name, True, rv[0], rv[1]))
300
301 if (head):
302 outf.seek(root_start)
303 for dir_entry in directory:
304 outf.write(dir_entry.pack())
305 else:
306 return write_directory(directory, outf, cluster_size, data_start, fat, reserved_clusters, dirent_size, empty_cluster)
307
308BOOT_SECTOR = """little:
309 uint8_t jmp[3] /* jump instruction */
310 char oem[8] /* OEM string */
311 uint16_t sector /* bytes per sector */
312 uint8_t cluster /* sectors per cluster */
313 uint16_t reserved /* reserved sectors */
314 uint8_t fats /* number of FATs */
315 uint16_t rootdir /* root directory entries */
316 uint16_t sectors /* total number of sectors */
317 uint8_t descriptor /* media descriptor */
318 uint16_t fat_sectors /* sectors per single FAT */
319 uint16_t track_sectors /* sectors per track */
320 uint16_t heads /* number of heads */
321 uint32_t hidden /* hidden sectors */
322 uint32_t sectors_big /* total number of sectors (if sectors == 0) */
323
324 /* Extended BIOS Parameter Block */
325 uint8_t drive /* physical drive number */
326 padding[1] /* reserved (current head) */
327 uint8_t extboot_signature /* extended boot signature */
328 uint32_t serial /* serial number */
329 char label[11] /* volume label */
330 char fstype[8] /* filesystem type */
331 padding[448] /* boot code */
332 uint8_t boot_signature[2] /* boot signature */
333"""
334
335EMPTY_SECTOR = """little:
336 padding[512] /* empty sector data */
337"""
338
339FAT_ENTRY = """little:
340 uint16_t next /* FAT16 entry */
341"""
342
343def usage(prname):
344 "Print usage syntax"
345 print prname + " <PATH> <IMAGE>"
346
347def main():
348 if (len(sys.argv) < 3):
349 usage(sys.argv[0])
350 return
351
352 path = os.path.abspath(sys.argv[1])
353 if (not os.path.isdir(path)):
354 print "<PATH> must be a directory"
355 return
356
357 fat16_clusters = 4096
358
359 sector_size = 512
360 cluster_size = 4096
361 dirent_size = 32
362 fatent_size = 2
363 fat_count = 2
364 reserved_clusters = 2
365
366 # Make sure the filesystem is large enought for FAT16
367 size = subtree_size(path, cluster_size, dirent_size) + reserved_clusters * cluster_size
368 while (size / cluster_size < fat16_clusters):
369 if (cluster_size > sector_size):
370 cluster_size /= 2
371 size = subtree_size(path, cluster_size, dirent_size) + reserved_clusters * cluster_size
372 else:
373 size = fat16_clusters * cluster_size + reserved_clusters * cluster_size
374
375 root_size = align_up(root_entries(path) * dirent_size, cluster_size)
376
377 fat_size = align_up(align_up(size, cluster_size) / cluster_size * fatent_size, sector_size)
378
379 sectors = (cluster_size + fat_count * fat_size + root_size + size) / sector_size
380 root_start = cluster_size + fat_count * fat_size
381 data_start = root_start + root_size
382
383 outf = file(sys.argv[2], "w")
384
385 boot_sector = xstruct.create(BOOT_SECTOR)
386 boot_sector.jmp = [0xEB, 0x3C, 0x90]
387 boot_sector.oem = "MSDOS5.0"
388 boot_sector.sector = sector_size
389 boot_sector.cluster = cluster_size / sector_size
390 boot_sector.reserved = cluster_size / sector_size
391 boot_sector.fats = fat_count
392 boot_sector.rootdir = root_size / dirent_size
393 if (sectors <= 65535):
394 boot_sector.sectors = sectors
395 else:
396 boot_sector.sectors = 0
397 boot_sector.descriptor = 0xF8
398 boot_sector.fat_sectors = fat_size / sector_size
399 boot_sector.track_sectors = 63
400 boot_sector.heads = 6
401 boot_sector.hidden = 0
402 if (sectors > 65535):
403 boot_sector.sectors_big = sectors
404 else:
405 boot_sector.sectors_big = 0
406
407 boot_sector.drive = 0x80
408 boot_sector.extboot_signature = 0x29
409 boot_sector.serial = random.randint(0, 0x7fffffff)
410 boot_sector.label = "HELENOS"
411 boot_sector.fstype = "FAT16 "
412 boot_sector.boot_signature = [0x55, 0xAA]
413
414 outf.write(boot_sector.pack())
415
416 empty_sector = xstruct.create(EMPTY_SECTOR)
417
418 # Reserved sectors
419 for i in range(1, cluster_size / sector_size):
420 outf.write(empty_sector.pack())
421
422 # FAT tables
423 for i in range(0, fat_count):
424 for j in range(0, fat_size / sector_size):
425 outf.write(empty_sector.pack())
426
427 # Root directory
428 for i in range(0, root_size / sector_size):
429 outf.write(empty_sector.pack())
430
431 # Data
432 for i in range(0, size / sector_size):
433 outf.write(empty_sector.pack())
434
435 fat = array.array('L', [0] * (fat_size / fatent_size))
436 fat[0] = 0xfff8
437 fat[1] = 0xffff
438
439 recursion(True, path, outf, cluster_size, root_start, data_start, fat, reserved_clusters, dirent_size, 0)
440
441 # Store FAT
442 fat_entry = xstruct.create(FAT_ENTRY)
443 for i in range(0, fat_count):
444 outf.seek(cluster_size + i * fat_size)
445 for j in range(0, fat_size / fatent_size):
446 fat_entry.next = fat[j]
447 outf.write(fat_entry.pack())
448
449 outf.close()
450
451if __name__ == '__main__':
452 main()
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