kernel_versions.py revision 753362d363fb183f32b4403d13ccc051438641e1 
1#
2# kernel_versions.py -- linux kernel version comparisons
3#
4__author__ = """Copyright Andy Whitcroft 2007"""
5
6import sys,re
7
8#
9# Sort key for ordering versions chronologically.  The key ordering
10# problem is between that introduced by -rcN.  These come _before_
11# their accompanying version.
12#
13#   2.6.0 -> 2.6.1-rc1 -> 2.6.1
14#
15# In order to sort them we convert all non-rc releases to a pseudo
16# -rc99 release.  We also convert all numbers to two digits.  The
17# result is then sortable textually.
18#
19#   02.06.00-rc99 -> 02.06.01-rc01 -> 02.06.01-rc99
20#
21encode_sep = re.compile(r'(\D+)')
22
23def version_encode(version):
24    bits = encode_sep.split(version)
25    n = 9
26    if len(bits[0]) == 0:
27        n += 2
28    if len(bits) == n or (len(bits) > n and bits[n] != '_rc'):
29        # Insert missing _rc99 after 2 . 6 . 18 -smp- 220 . 0
30        bits.insert(n, '_rc')
31        bits.insert(n+1, '99')
32    n = 5
33    if len(bits[0]) == 0:
34        n += 2
35    if len(bits) <= n or bits[n] != '-rc':
36        bits.insert(n, '-rc')
37        bits.insert(n+1, '99')
38    for n in range(0, len(bits), 2):
39        if len(bits[n]) == 1:
40            bits[n] = '0' + bits[n]
41
42    return ''.join(bits)
43
44
45def version_limit(version, n):
46    bits = encode_sep.split(version)
47    return ''.join(bits[0:n])
48
49
50def version_len(version):
51    return len(encode_sep.split(version))
52
53#
54# Given a list of versions find the nearest version which is deemed
55# less than or equal to the target.  Versions are in linux order
56# as follows:
57#
58#   2.6.0 -> 2.6.1 -> 2.6.2-rc1 -> 2.6.2-rc2 -> 2.6.2 -> 2.6.3-rc1
59#              |        |\
60#              |        | 2.6.2-rc1-mm1 -> 2.6.2-rc1-mm2
61#              |        \
62#              |         2.6.2-rc1-ac1 -> 2.6.2-rc1-ac2
63#              \
64#               2.6.1-mm1 -> 2.6.1-mm2
65#
66# Note that a 2.6.1-mm1 is not a predecessor of 2.6.2-rc1-mm1.
67#
68def version_choose_config(version, candidates):
69    # Check if we have an exact match ... if so magic
70    if version in candidates:
71        return version
72
73    # Sort the search key into the list ordered by 'age'
74    deco = [ (version_encode(v), i, v) for i, v in
75                                    enumerate(candidates + [ version ]) ]
76    deco.sort()
77    versions = [ v for _, _, v in deco ]
78
79    # Everything sorted below us is of interst.
80    for n in range(len(versions) - 1, -1, -1):
81        if versions[n] == version:
82            break
83    n -= 1
84
85    # Try ever shorter 'prefixes' 2.6.20-rc3-mm, 2.6.20-rc, 2.6. etc
86    # to match against the ordered list newest to oldest.
87    length = version_len(version) - 1
88    version = version_limit(version, length)
89    while length > 1:
90        for o in range(n, -1, -1):
91            if version_len(versions[o]) == (length + 1) and \
92                                version_limit(versions[o], length) == version:
93                return versions[o]
94        length -= 2
95        version = version_limit(version, length)
96
97    return None
98
99
100def is_released_kernel(version):
101    # True if version name suggests a released kernel,
102    #   not some release candidate or experimental kernel name
103    #   e.g.  2.6.18-smp-200.0  includes no other text, underscores, etc
104    version = version.strip('01234567890.-')
105    return version in ['', 'smp', 'smpx', 'pae']
106
107
108def is_release_candidate(version):
109    # True if version names a released kernel or release candidate,
110    #   not some experimental name containing arbitrary text
111    #   e.g.  2.6.18-smp-220.0_rc3  but not  2.6.18_patched
112    version = re.sub(r'[_-]rc\d+', '', version)
113    return is_released_kernel(version)
114