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
   7 import os
   8 import string
   9 import re
  10
  11 inname = sys.argv[1]
  12 outname = sys.argv[2]
  13
  14 outdir = os.path.dirname(os.path.abspath(outname))
  15 if not os.path.isdir(outdir):
  16     os.makedirs(outdir)
  17
  18 # these are regexes to avoid a compile-time/host dependency on yang-tools
  19 # or python-yang.  Cross-compiling FRR is already somewhat involved, no need
  20 # to make it even harder.
  21
  22 re_name = re.compile(r'\bmodule\s+([^\s]+)\s+\{')
  23 re_rev = re.compile(r'\brevision\s+([\d-]+)\s+\{')
  24
  25
  26 template = '''/* autogenerated by embedmodel.py.  DO NOT EDIT */
  27
  28 #include <zebra.h>
  29 #include "yang.h"
  30
  31 static const char model[] =
  32 \t"%s";
  33
  34 static struct yang_module_embed embed = {
  35 \t.mod_name = "%s",
  36 \t.mod_rev = "%s",
  37 \t.data = model,
  38 \t.format = %s,
  39 };
  40
  41 static void embed_register(void) __attribute__((_CONSTRUCTOR(2000)));
  42 static void embed_register(void)
  43 {
  44 \tyang_module_embed(&embed);
  45 }
  46 '''
  47
  48 passchars = set(string.printable) - set('\\\'"%\r\n\t\x0b\x0c')
  49 def escapech(char):
  50     if char in passchars:
  51         return char
  52     if char == '\n':
  53         return '\\n'
  54     if char == '\t':
  55         return '\\t'
  56     if char in '"\\\'':
  57         return '\\' + char
  58     return '\\x%02x' % (ord(char))
  59 def escape(line):
  60     return ''.join([escapech(i) for i in line])
  61
  62 with open(inname, 'r') as fd:
  63     data = fd.read()
  64
  65 # XML support isn't actively used currently, but it's here in case the need
  66 # arises.  It does avoid the regex'ing.
  67 if '<?xml' in data:
  68     from xml.etree import ElementTree
  69     xml = ElementTree.fromstring(data)
  70     name = xml.get('name')
  71     rev = xml.find('{urn:ietf:params:xml:ns:yang:yin:1}revision').get('date')
  72     fmt = 'LYS_YIN'
  73 else:
  74     name = re_name.search(data).group(1)
  75     rev = re_rev.search(data).group(1)
  76     fmt = 'LYS_YANG'
  77
  78 if name is None or rev is None:
  79     raise ValueError('cannot determine YANG module name and revision')
  80
  81 lines = [escape(row) for row in data.split('\n')]
  82 text = '\\n"\n\t"'.join(lines)
  83
  84 with open(outname, 'w') as fd:
  85     fd.write(template % (text, escape(name), escape(rev), fmt))