yang/embedmodel.py

   1 #!/usr/bin/python3
   2 #
   3 # YANG module to C wrapper
   4 # written 2018 by David Lamparter, placed in Public Domain.
   5
   6 import sys, string, re
   7
   8 inname = sys.argv[1]
   9 outname = sys.argv[2]
  10
  11 # these are regexes to avoid a compile-time/host dependency on yang-tools
  12 # or python-yang.  Cross-compiling FRR is already somewhat involved, no need
  13 # to make it even harder.
  14
  15 re_name = re.compile(r'\bmodule\s+([^\s]+)\s+\{')
  16 re_rev = re.compile(r'\brevision\s+([\d-]+)\s+\{')
  17
  18
  19 template = '''/* autogenerated by embedmodel.py.  DO NOT EDIT */
  20
  21 #include <zebra.h>
  22 #include "yang.h"
  23
  24 static const char model[] =
  25 \t"%s";
  26
  27 static struct yang_module_embed embed = {
  28 \t.mod_name = "%s",
  29 \t.mod_rev = "%s",
  30 \t.data = model,
  31 \t.format = %s,
  32 };
  33
  34 static void embed_register(void) __attribute__((_CONSTRUCTOR(2000)));
  35 static void embed_register(void)
  36 {
  37 \tyang_module_embed(&embed);
  38 }
  39 '''
  40
  41 passchars = set(string.printable) - set('\\\'"%\r\n\t\x0b\x0c')
  42 def escapech(char):
  43     if char in passchars:
  44         return char
  45     if char == '\n':
  46         return '\\n'
  47     if char == '\t':
  48         return '\\t'
  49     if char in '"\\\'':
  50         return '\\' + char
  51     return '\\x%02x' % (ord(char))
  52 def escape(line):
  53     return ''.join([escapech(i) for i in line])
  54
  55 with open(inname, 'r') as fd:
  56     data = fd.read()
  57
  58 # XML support isn't actively used currently, but it's here in case the need
  59 # arises.  It does avoid the regex'ing.
  60 if '<?xml' in data:
  61     from xml.etree import ElementTree
  62     xml = ElementTree.fromstring(data)
  63     name = xml.get('name')
  64     rev = xml.find('{urn:ietf:params:xml:ns:yang:yin:1}revision').get('date')
  65     fmt = 'LYS_YIN'
  66 else:
  67     name = re_name.search(data).group(1)
  68     rev = re_rev.search(data).group(1)
  69     fmt = 'LYS_YANG'
  70
  71 if name is None or rev is None:
  72     raise ValueError('cannot determine YANG module name and revision')
  73
  74 lines = [escape(row) for row in data.split('\n')]
  75 text = '\\n"\n\t"'.join(lines)
  76
  77 with open(outname, 'w') as fd:
  78     fd.write(template % (text, escape(name), escape(rev), fmt))