Christopher Haster
4d8bfeae71
It would be nice to have a full 8-bit range for both user attrs and system attrs, for both backwards compatibility and maximizing the available attr space, but I think it just doesn't make sense from an API perspective. Sure we could finagle the user/sys bit into a flags argument, or provide separate lfsr_getuattr/getsattr functions, but asking users to use a 9-bit int for higher-level operations (dynamic attrs, iteration, etc) is a bit much... So this reduces the two attr ranges down to 7-bits, requiring 8-bits total to store all possible attr types in the current system: TAG_ATTR 0x0400 v--- -1-a -aaa aaaa TAG_UATTR 0x04aa v--- -1-- -aaa aaaa TAG_SATTR 0x05aa v--- -1-1 -aaa aaaa This really just affects scripts, since we haven't actually implemented attributes yet. Worst case we still have the 9-bit encoding space carved out, so we can always add an additional set of attrs in the future if we start running into attr pressure. Or, you know, just turn on the subtype leb128 encoding the 8th subtype bit is reserved for. Then you'd only be limited by internal driver details, probably 24-bits per attr range if we make tags 32-bits internally. Though this would probably come with quite a code cost...
359 lines
12 KiB
Python
Executable File
359 lines
12 KiB
Python
Executable File
#!/usr/bin/env python3
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import io
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import os
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import struct
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import sys
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TAG_NULL = 0x0000 ## 0x0000 v--- ---- ---- ----
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TAG_CONFIG = 0x0000 ## 0x00tt v--- ---- -ttt tttt
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TAG_MAGIC = 0x0003 # 0x0003 v--- ---- ---- --11
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TAG_VERSION = 0x0004 # 0x0004 v--- ---- ---- -1--
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TAG_RCOMPAT = 0x0005 # 0x0005 v--- ---- ---- -1-1
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TAG_WCOMPAT = 0x0006 # 0x0006 v--- ---- ---- -11-
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TAG_OCOMPAT = 0x0007 # 0x0007 v--- ---- ---- -111
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TAG_GEOMETRY = 0x0009 # 0x0008 v--- ---- ---- 1-rr
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TAG_NAMELIMIT = 0x000c # 0x000c v--- ---- ---- 11--
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TAG_FILELIMIT = 0x000d # 0x000d v--- ---- ---- 11-1
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TAG_GDELTA = 0x0100 ## 0x01tt v--- ---1 -ttt tttt
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TAG_GRMDELTA = 0x0100 # 0x0100 v--- ---1 ---- ----
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TAG_NAME = 0x0200 ## 0x02tt v--- --1- -ttt tttt
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TAG_REG = 0x0201 # 0x0201 v--- --1- ---- ---1
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TAG_DIR = 0x0202 # 0x0202 v--- --1- ---- --1-
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TAG_BOOKMARK = 0x0204 # 0x0204 v--- --1- ---- -1--
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TAG_ORPHAN = 0x0205 # 0x0205 v--- --1- ---- -1-1
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TAG_STRUCT = 0x0300 ## 0x03tt v--- --11 -ttt tttt
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TAG_DATA = 0x0300 # 0x0300 v--- --11 ---- ----
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TAG_BLOCK = 0x0304 # 0x0304 v--- --11 ---- -1rr
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TAG_BSHRUB = 0x0308 # 0x0308 v--- --11 ---- 1---
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TAG_BTREE = 0x030c # 0x030c v--- --11 ---- 11rr
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TAG_MROOT = 0x0311 # 0x0310 v--- --11 ---1 --rr
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TAG_MDIR = 0x0315 # 0x0314 v--- --11 ---1 -1rr
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TAG_MTREE = 0x031c # 0x031c v--- --11 ---1 11rr
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TAG_DID = 0x0320 # 0x0320 v--- --11 --1- ----
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TAG_BRANCH = 0x032c # 0x032c v--- --11 --1- 11rr
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TAG_ATTR = 0x0400 ## 0x04aa v--- -1-a -aaa aaaa
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TAG_UATTR = 0x0400 # 0x04aa v--- -1-- -aaa aaaa
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TAG_SATTR = 0x0500 # 0x05aa v--- -1-1 -aaa aaaa
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TAG_SHRUB = 0x1000 ## 0x1kkk v--1 kkkk -kkk kkkk
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TAG_ALT = 0x4000 ## 0x4kkk v1cd kkkk -kkk kkkk
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TAG_B = 0x0000
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TAG_R = 0x2000
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TAG_LE = 0x0000
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TAG_GT = 0x1000
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TAG_CKSUM = 0x3000 ## 0x3c0p v-11 cccc ---- --qp
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TAG_P = 0x0001
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TAG_Q = 0x0002
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TAG_NOTE = 0x3100 # 0x3100 v-11 ---1 ---- ----
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TAG_ECKSUM = 0x3200 # 0x3200 v-11 --1- ---- ----
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# some ways of block geometry representations
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# 512 -> 512
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# 512x16 -> (512, 16)
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# 0x200x10 -> (512, 16)
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def bdgeom(s):
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s = s.strip()
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b = 10
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if s.startswith('0x') or s.startswith('0X'):
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s = s[2:]
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b = 16
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elif s.startswith('0o') or s.startswith('0O'):
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s = s[2:]
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b = 8
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elif s.startswith('0b') or s.startswith('0B'):
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s = s[2:]
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b = 2
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if 'x' in s:
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s, s_ = s.split('x', 1)
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return (int(s, b), int(s_, b))
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else:
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return int(s, b)
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# parse some rbyd addr encodings
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# 0xa -> [0xa]
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# 0xa.c -> [(0xa, 0xc)]
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# 0x{a,b} -> [0xa, 0xb]
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# 0x{a,b}.c -> [(0xa, 0xc), (0xb, 0xc)]
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def rbydaddr(s):
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s = s.strip()
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b = 10
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if s.startswith('0x') or s.startswith('0X'):
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s = s[2:]
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b = 16
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elif s.startswith('0o') or s.startswith('0O'):
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s = s[2:]
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b = 8
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elif s.startswith('0b') or s.startswith('0B'):
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s = s[2:]
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b = 2
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trunk = None
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if '.' in s:
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s, s_ = s.split('.', 1)
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trunk = int(s_, b)
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if s.startswith('{') and '}' in s:
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ss = s[1:s.find('}')].split(',')
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else:
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ss = [s]
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addr = []
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for s in ss:
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if trunk is not None:
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addr.append((int(s, b), trunk))
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else:
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addr.append(int(s, b))
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return addr
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def fromleb128(data):
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word = 0
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for i, b in enumerate(data):
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word |= ((b & 0x7f) << 7*i)
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word &= 0xffffffff
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if not b & 0x80:
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return word, i+1
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return word, len(data)
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def tagrepr(tag, w=None, size=None, off=None):
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if (tag & 0x6fff) == TAG_NULL:
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return '%snull%s%s' % (
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'shrub' if tag & TAG_SHRUB else '',
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' w%d' % w if w else '',
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' %d' % size if size else '')
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elif (tag & 0x6f00) == TAG_CONFIG:
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return '%s%s%s%s' % (
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'shrub' if tag & TAG_SHRUB else '',
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'magic' if (tag & 0xfff) == TAG_MAGIC
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else 'version' if (tag & 0xfff) == TAG_VERSION
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else 'rcompat' if (tag & 0xfff) == TAG_RCOMPAT
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else 'wcompat' if (tag & 0xfff) == TAG_WCOMPAT
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else 'ocompat' if (tag & 0xfff) == TAG_OCOMPAT
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else 'geometry' if (tag & 0xfff) == TAG_GEOMETRY
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else 'namelimit' if (tag & 0xfff) == TAG_NAMELIMIT
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else 'filelimit' if (tag & 0xfff) == TAG_FILELIMIT
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else 'config 0x%02x' % (tag & 0xff),
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' w%d' % w if w else '',
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' %s' % size if size is not None else '')
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elif (tag & 0x6f00) == TAG_GDELTA:
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return '%s%s%s%s' % (
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'shrub' if tag & TAG_SHRUB else '',
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'grmdelta' if (tag & 0xfff) == TAG_GRMDELTA
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else 'gdelta 0x%02x' % (tag & 0xff),
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' w%d' % w if w else '',
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' %s' % size if size is not None else '')
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elif (tag & 0x6f00) == TAG_NAME:
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return '%s%s%s%s' % (
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'shrub' if tag & TAG_SHRUB else '',
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'name' if (tag & 0xfff) == TAG_NAME
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else 'reg' if (tag & 0xfff) == TAG_REG
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else 'dir' if (tag & 0xfff) == TAG_DIR
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else 'orphan' if (tag & 0xfff) == TAG_ORPHAN
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else 'bookmark' if (tag & 0xfff) == TAG_BOOKMARK
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else 'name 0x%02x' % (tag & 0xff),
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' w%d' % w if w else '',
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' %s' % size if size is not None else '')
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elif (tag & 0x6f00) == TAG_STRUCT:
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return '%s%s%s%s' % (
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'shrub' if tag & TAG_SHRUB else '',
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'data' if (tag & 0xfff) == TAG_DATA
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else 'block' if (tag & 0xfff) == TAG_BLOCK
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else 'bshrub' if (tag & 0xfff) == TAG_BSHRUB
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else 'btree' if (tag & 0xfff) == TAG_BTREE
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else 'mroot' if (tag & 0xfff) == TAG_MROOT
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else 'mdir' if (tag & 0xfff) == TAG_MDIR
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else 'mtree' if (tag & 0xfff) == TAG_MTREE
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else 'did' if (tag & 0xfff) == TAG_DID
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else 'branch' if (tag & 0xfff) == TAG_BRANCH
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else 'struct 0x%02x' % (tag & 0xff),
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' w%d' % w if w else '',
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' %s' % size if size is not None else '')
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elif (tag & 0x6e00) == TAG_ATTR:
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return '%s%sattr 0x%02x%s%s' % (
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'shrub' if tag & TAG_SHRUB else '',
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's' if tag & 0x100 else 'u',
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((tag & 0x100) >> 1) ^ (tag & 0xff),
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' w%d' % w if w else '',
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' %s' % size if size is not None else '')
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elif tag & TAG_ALT:
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return 'alt%s%s%s%s%s' % (
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'r' if tag & TAG_R else 'b',
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'a' if tag & 0x0fff == 0 and tag & TAG_GT
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else 'n' if tag & 0x0fff == 0
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else 'gt' if tag & TAG_GT
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else 'le',
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' 0x%x' % (tag & 0x0fff) if tag & 0x0fff != 0 else '',
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' w%d' % w if w is not None else '',
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' 0x%x' % (0xffffffff & (off-size))
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if size and off is not None
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else ' -%d' % size if size
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else '')
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elif (tag & 0x7f00) == TAG_CKSUM:
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return 'cksum%s%s%s%s%s' % (
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'q' if not tag & 0xfc and tag & TAG_Q else '',
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'p' if not tag & 0xfc and tag & TAG_P else '',
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' 0x%02x' % (tag & 0xff) if tag & 0xfc else '',
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' w%d' % w if w else '',
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' %s' % size if size is not None else '')
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elif (tag & 0x7f00) == TAG_NOTE:
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return 'note%s%s%s' % (
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' 0x%02x' % (tag & 0xff) if tag & 0xff else '',
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' w%d' % w if w else '',
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' %s' % size if size is not None else '')
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elif (tag & 0x7f00) == TAG_ECKSUM:
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return 'ecksum%s%s%s' % (
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' 0x%02x' % (tag & 0xff) if tag & 0xff else '',
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' w%d' % w if w else '',
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' %s' % size if size is not None else '')
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else:
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return '0x%04x%s%s' % (
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tag,
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' w%d' % w if w is not None else '',
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' %d' % size if size is not None else '')
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def list_tags():
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# here be magic, parse our script's source to get to the tag comments
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import inspect
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import re
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tags = []
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tag_pattern = re.compile(
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'^(?P<name>TAG_[^ ]*) *= *(?P<tag>[^ #]+) *#+ *(?P<comment>.*)$')
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for line in inspect.getsourcelines(
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inspect.getmodule(inspect.currentframe()))[0]:
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m = tag_pattern.match(line)
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if m:
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tags.append(m.groups())
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# find widths for alignment
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w = [0]
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for n, t, c in tags:
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w[0] = max(w[0], len('LFSR_'+n))
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# print
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for n, t, c in tags:
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print('%-*s %s' % (
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w[0], 'LFSR_'+n,
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c))
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def dbg_tag(data):
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if isinstance(data, int):
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tag = data
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weight = None
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size = None
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else:
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data = data.ljust(2, b'\0')
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tag = (data[0] << 8) | data[1]
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weight, d = fromleb128(data[2:]) if 2 < len(data) else (None, 2)
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size, d_ = fromleb128(data[2+d:]) if d < len(data) else (None, d)
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print(tagrepr(tag, weight, size))
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def main(tags, *,
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list=False,
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block_size=None,
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block_count=None,
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off=None,
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**args):
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list_, list = list, __builtins__.list
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# list all known tags
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if list_:
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list_tags()
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# try to decode these tags
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else:
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# interpret as a sequence of hex bytes
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if args.get('hex'):
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dbg_tag(bytes(int(tag, 16) for tag in tags))
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# interpret as strings
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elif args.get('string'):
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for tag in tags:
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dbg_tag(tag.encode('utf8'))
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# default to interpreting as ints
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elif block_size is None and off is None:
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for tag in tags:
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dbg_tag(int(tag, 0))
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# if either block_size or off provided interpret as a block device
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else:
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disk, *blocks = tags
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blocks = [rbydaddr(block) for block in blocks]
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# is bd geometry specified?
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if isinstance(block_size, tuple):
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block_size, block_count_ = block_size
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if block_count is None:
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block_count = block_count_
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# flatten block, default to block 0
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if not blocks:
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blocks = [[0]]
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blocks = [block for blocks_ in blocks for block in blocks_]
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with open(disk, 'rb') as f:
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# if block_size is omitted, assume the block device is one
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# big block
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if block_size is None:
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f.seek(0, os.SEEK_END)
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block_size = f.tell()
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# blocks may also encode offsets
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blocks, offs = (
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[block[0] if isinstance(block, tuple) else block
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for block in blocks],
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[off if off is not None
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else block[1] if isinstance(block, tuple)
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else None
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for block in blocks])
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# read each tag
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for block, off in zip(blocks, offs):
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f.seek((block * block_size) + (off or 0))
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# read maximum tag size
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data = f.read(2+5+5)
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dbg_tag(data)
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if __name__ == "__main__":
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import argparse
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import sys
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parser = argparse.ArgumentParser(
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description="Decode littlefs tags.",
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allow_abbrev=False)
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parser.add_argument(
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'tags',
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nargs='*',
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help="Tags to decode.")
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parser.add_argument(
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'-l', '--list',
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action='store_true',
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help="List all known tags.")
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parser.add_argument(
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'-x', '--hex',
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action='store_true',
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help="Interpret as a sequence of hex bytes.")
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parser.add_argument(
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'-s', '--string',
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action='store_true',
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help="Interpret as strings.")
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parser.add_argument(
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'-b', '--block-size',
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type=bdgeom,
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help="Block size/geometry in bytes.")
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parser.add_argument(
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'--block-count',
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type=lambda x: int(x, 0),
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help="Block count in blocks.")
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parser.add_argument(
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'--off',
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type=lambda x: int(x, 0),
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help="Use this offset.")
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sys.exit(main(**{k: v
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for k, v in vars(parser.parse_intermixed_args()).items()
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if v is not None}))
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