initdutils.py

   1 # Support for scanning init scripts for LSB info
   2
   3 import re, sys, os, cStringIO
   4 import cPickle
   5
   6 try:
   7     assert True
   8 except:
   9     True = 1
  10     False = 0
  11
  12 class RFC822Parser(dict):
  13     "A dictionary-like object."
  14     __linere = re.compile(r'([^:]+):\s*(.*)$')
  15
  16     def __init__(self, fileob=None, strob=None, startcol=0, basedict=None):
  17         if not fileob and not strob:
  18             raise ValueError, 'need a file or string'
  19         if not basedict:
  20             basedict = {}
  21
  22         super(RFC822Parser, self).__init__(basedict)
  23
  24         if not fileob:
  25             fileob = cStringIO.StringIO(strob)
  26
  27         key = None
  28         for line in fileob:
  29             if startcol:
  30                 line = line[startcol:]
  31
  32             if not line.strip():
  33                 continue
  34
  35             # Continuation line
  36             if line[0].isspace():
  37                 if not key:
  38                     continue
  39                 self[key] += '\n' + line.strip()
  40                 continue
  41
  42             m = self.__linere.match(line)
  43             if not m:
  44                 # Not a valid RFC822 header
  45                 continue
  46             key, value = m.groups()
  47             self[key] = value.strip()
  48
  49 # End of RFC882Parser
  50
  51 LSBLIB = '/var/lib/lsb'
  52 FACILITIES = os.path.join(LSBLIB, 'facilities')
  53 DEPENDS = os.path.join(LSBLIB, 'depends')
  54 LSBINSTALL = os.path.join(LSBLIB, 'lsbinstall')
  55
  56 beginre = re.compile(re.escape('### BEGIN INIT INFO'))
  57 endre = re.compile(re.escape('### END INIT INFO'))
  58 #linere = re.compile(r'\#\s+([^:]+):\s*(.*)')
  59
  60 def scan_initfile(initfile):
  61     headerlines = ''
  62     scanning = False
  63
  64     for line in file(initfile):
  65         line = line.rstrip()
  66         if beginre.match(line):
  67             scanning = True
  68             continue
  69         elif scanning and endre.match(line):
  70             scanning = False
  71             continue
  72         elif not scanning:
  73             continue
  74
  75         if line.startswith('# '):
  76             headerlines += line[2:] + '\n'
  77         elif line.startswith('#\t'):
  78             headerlines += line[1:] + '\n'
  79
  80     inheaders = RFC822Parser(strob=headerlines)
  81     headers = {}
  82     for header, body in inheaders.iteritems():
  83         # Ignore empty headers
  84         if not body.strip():
  85             continue
  86
  87         if header in ('Default-Start', 'Default-Stop'):
  88             headers[header] = map(int, body.split())
  89         elif header in ('Required-Start', 'Required-Stop', 'Provides',
  90                         'Should-Start', 'Should-Stop'):
  91             headers[header] = body.split()
  92         else:
  93             headers[header] = body
  94
  95     return headers
  96
  97 def save_facilities(facilities):
  98     if not facilities:
  99         try:
 100             os.unlink(FACILITIES)
 101         except OSError:
 102             pass
 103         return
 104
 105     fh = file(FACILITIES, 'w')
 106     for facility, entries in facilities.items():
 107         # Ignore system facilities
 108         if facility.startswith('$'): continue
 109         for (scriptname, pri) in entries.items():
 110             start, stop = pri
 111             print >> fh, "%(scriptname)s %(facility)s %(start)d %(stop)d" % locals()
 112     fh.close()
 113
 114 def load_facilities():
 115     facilities = {}
 116     if os.path.exists(FACILITIES):
 117         for line in open(FACILITIES).xreadlines():
 118             try:
 119                 scriptname, name, start, stop = line.strip().split()
 120                 facilities.setdefault(name, {})[scriptname] = (int(start),
 121                                                                int(stop))
 122             except ValueError, x:
 123                 print >> sys.stderr, 'Invalid facility line', line
 124
 125     return facilities
 126
 127 def load_depends():
 128     depends = {}
 129
 130     if os.path.exists(DEPENDS):
 131         independs = RFC822Parser(fileob=file(DEPENDS))
 132         for initfile, facilities in independs.iteritems():
 133             depends[initfile] = facilities.split()
 134     return depends
 135
 136 def save_depends(depends):
 137     if not depends:
 138         try:
 139             os.unlink(DEPENDS)
 140         except OSError:
 141             pass
 142         return
 143
 144     fh = file(DEPENDS, 'w')
 145     for initfile, facilities in depends.iteritems():
 146         print >> fh, '%s: %s' % (initfile, ' '.join(facilities))
 147     fh.close()
 148
 149 # filemap entries are mappings, { (package, filename) : instloc }
 150 def load_lsbinstall_info():
 151     if not os.path.exists(LSBINSTALL):
 152         return {}
 153
 154     fh = open(LSBINSTALL, 'rb')
 155     filemap = cPickle.load(fh)
 156     fh.close()
 157
 158     # Just in case it's corrupted somehow
 159     if not isinstance(filemap, dict):
 160         return {}
 161
 162     return filemap
 163
 164 def save_lsbinstall_info(filemap):
 165     if not filemap:
 166         try:
 167             os.unlink(LSBINSTALL)
 168         except OSError:
 169             pass
 170         return
 171
 172     fh = open(LSBINSTALL, 'wb')
 173     cPickle.dump(fh, filemap)
 174     fh.close()
 175
 176 if __name__ == '__main__':
 177     print scan_initfile('init-fragment')