Hi All,I'm Balaji Rao, looking to contribute to HelenOS through Google Summer of Code 2012.
I got started by building the ia32 toolchain on linux and could build the mainline and boot it on KVM.
Next, I started looking at the open tickets. The one "mkfat.py does not support LFN" sounded fun and quickly doable. After hacking on it for a few hours, I managed to complete it. I've included the patch as an attachment and inline (doesn't this make commenting easier ?) I've tested it on Helenos and both msdos and vfat filesystems of Linux.
Of the projects listed, I am interested in the following, (in increasing order of priority).
1. Support PAE on ia32 2. Implement stack guard pages 3. Support for DWARF Debugging Information Format.If anyone can tell me which among these has higher priority for HelenOS, it will help me decide before I apply.
Please suggest me how I can take it forward from here.
Thank You,
Balaji
---
=== modified file 'tools/mkfat.py'
--- tools/mkfat.py 2011-07-24 21:18:16 +0000
+++ tools/mkfat.py 2012-03-26 18:44:46 +0000
@@ -167,49 +167,109 @@
uint32_t size /* file size */
"""
-def mangle_fname(name):
+LFN_ENTRY = """little:
+ uint8_t pos
+ uint16_t name1[5]
+ uint8_t attr
+ uint8_t type
+ uint8_t csum
+ uint16_t name2[6]
+ uint16_t fc
+ uint16_t name3[2]
+"""
+
+# Global variable to hold the file names in 8.3 format. Needed to
+# keep track of "number" when creating a short fname from a LFN.
+name83_list = []
+
+def name83(fname):
+ "Create a 8.3 name for the given fname"
+
# FIXME: filter illegal characters
- parts = name.split('.')
+ parts = fname.split('.')
+ name = ''
+ ext = ''
+ lfn = False
+
+ if len(fname) > 11 :
+ lfn = True
+
if len(parts) > 0:
- fname = parts[0]
- else:
- fname = ''
-
- if len(fname) > 8:
- sys.stdout.write("mkfat.py: error: Directory entry " + name +
- " base name is longer than 8 characters\n")
- sys.exit(1);
-
- return (fname + ' ').upper()[0:8]
-
-def mangle_ext(name):
- # FIXME: filter illegal characters
- parts = name.split('.')
-
- if len(parts) > 1:
- ext = parts[1]
- else:
- ext = ''
-
- if len(parts) > 2:
- sys.stdout.write("mkfat.py: error: Directory entry " + name +
- " has more than one extension\n")
- sys.exit(1);
-
- if len(ext) > 3:
- sys.stdout.write("mkfat.py: error: Directory entry " + name +
- " extension is longer than 3 characters\n")
- sys.exit(1);
-
- return (ext + ' ').upper()[0:3]
+ name = parts[0]
+ if len(name) > 8 :
+ lfn = True
+
+ if len(parts) > 1 :
+ ext = parts[-1]
+ if len(ext) > 3 :
+ lfn = True
+
+ if len(parts) > 2 :
+ lfn = True
+
+ if (lfn == False) :
+ return (name.ljust(8)[0:8], ext.ljust(3)[0:3], False)
+
+ # For filenames with multiple extensions, we treat the last one
+ # as the actual extension. The rest of the filename is stripped
+ # of dots and concatenated to form the short name
+ for _name in parts[1:-1]:
+ name = name + _name
+
+ global name83_list
+ for number in range(1, 10000) :
+ number_str = '~' + str(number)
+
+ if len(name) + len(number_str) > 8 :
+ name = name[0:8 - len(number_str)]
+
+ name = name + number_str;
+
+ if (name + ext) not in name83_list :
+ break
+
+ name83_list.append(name + ext)
+
+ return (name.ljust(8)[0:8], ext.ljust(3)[0:3], True)
+
+def get_utf16(name, l) :
+ "Create a int array out of a string which we can
+ store in uint16_t arrays"
+
+ bs = [0xFFFF for i in range(l)]
+
+ for i in range(len(name)) :
+ bs[i] = ord(name[i])
+
+ if (len(name) < l) :
+ bs[len(name)] = 0;
+
+ return bs
+
+def create_lfn_entry((name, index)) :
+ entry = xstruct.create(LFN_ENTRY)
+
+ entry.name1 = get_utf16(name[0:5], 5)
+ entry.name2 = get_utf16(name[5:11], 6)
+ entry.name3 = get_utf16(name[11:13], 2)
+ entry.pos = index
+
+ entry.attr = 0xF
+ entry.fc = 0
+ entry.type = 0
+
+ return entry
def create_dirent(name, directory, cluster, size):
+
dir_entry = xstruct.create(DIR_ENTRY)
- dir_entry.name = mangle_fname(name).encode('ascii')
- dir_entry.ext = mangle_ext(name).encode('ascii')
-
+ dir_entry.name, dir_entry.ext, lfn = name83(name)
+
+ dir_entry.name = dir_entry.name.upper().encode('ascii')
+ dir_entry.ext = dir_entry.ext.upper().encode('ascii')
+
if (directory):
dir_entry.attr = 0x30
else:
@@ -229,7 +289,29 @@
else:
dir_entry.size = size
- return dir_entry
+
+ if not lfn:
+ return [dir_entry]
+
+ n = len(name) / 13 + 1
+ names = [(name[i * 13: (i + 1) * 13 + 1], i + 1) for i in range(n)]
+
+ entries = sorted(map (create_lfn_entry, names), reverse = True, key
= lambda e : e.pos)
+ entries[0].pos |= 0x40
+
+ fname11 = dir_entry.name + dir_entry.ext
+
+ csum = 0
+ for i in range(0, 11) :
+ csum = ((sum & 1) << 7) + (sum >> 1) + ord(fname11[i])
+ csum = sum & 0xFF
+
+ for e in entries :
+ e.csum = sum;
+
+ entries.append(dir_entry)
+
+ return entries
def create_dot_dirent(empty_cluster):
dir_entry = xstruct.create(DOT_DIR_ENTRY)
@@ -287,10 +369,10 @@
for item in listdir_items(root):
if item.is_file:
rv = write_file(item, outf, cluster_size, data_start, fat,
reserved_clusters)
- directory.append(create_dirent(item.name, False, rv[0], rv[1]))
+ directory.extend(create_dirent(item.name, False, rv[0], rv[1]))
elif item.is_dir:
rv = recursion(False, item.path, outf, cluster_size,
root_start, data_start, fat, reserved_clusters, dirent_size, empty_cluster)
- directory.append(create_dirent(item.name, True, rv[0], rv[1]))
+ directory.extend(create_dirent(item.name, True, rv[0], rv[1]))
if (head):
outf.seek(root_start)
patch.bz2
Description: application/bzip
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