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_subname = re.compile(r'\bsubmodule\s+([^\s]+)\s+\{')
  24 re_mainname = re.compile(r'\bbelongs-to\s+([^\s]+)\s+\{')
  25 re_rev = re.compile(r'\brevision\s+([\d-]+)\s+\{')
  26
  27
  28 template = '''/* autogenerated by embedmodel.py.  DO NOT EDIT */
  29
  30 #include <zebra.h>
  31 #include "yang.h"
  32
  33 static const char model[] =
  34 \t"%s";
  35
  36 static struct yang_module_embed embed = {
  37 \t.mod_name = "%s",
  38 \t.mod_rev = "%s",
  39 \t.sub_mod_name = "%s",
  40 \t.sub_mod_rev = "%s",
  41 \t.data = model,
  42 \t.format = %s,
  43 };
  44
  45 static void embed_register(void) __attribute__((_CONSTRUCTOR(2000)));
  46 static void embed_register(void)
  47 {
  48 \tyang_module_embed(&embed);
  49 }
  50 '''
  51
  52 passchars = set(string.printable) - set('\\\'"%\r\n\t\x0b\x0c')
  53 def escapech(char):
  54     if char in passchars:
  55         return char
  56     if char == '\n':
  57         return '\\n'
  58     if char == '\t':
  59         return '\\t'
  60     if char in '"\\\'':
  61         return '\\' + char
  62     return '\\x%02x' % (ord(char))
  63 def escape(line):
  64     return ''.join([escapech(i) for i in line])
  65
  66 with open(inname, 'r') as fd:
  67     data = fd.read()
  68
  69 sub_name = ""
  70 rev = ""
  71 sub_rev = ""
  72
  73 # XML support isn't actively used currently, but it's here in case the need
  74 # arises.  It does avoid the regex'ing.
  75 if '<?xml' in data:
  76     from xml.etree import ElementTree
  77     xml = ElementTree.fromstring(data)
  78     name = xml.get('name')
  79     rev = xml.find('{urn:ietf:params:xml:ns:yang:yin:1}revision').get('date')
  80     fmt = 'LYS_YIN'
  81 else:
  82     search_name = re_name.search(data)
  83     if search_name :
  84        name = search_name.group(1)
  85        rev = re_rev.search(data).group(1)
  86     else :
  87        search_name = re_subname.search(data)
  88        sub_name = search_name.group(1)
  89        name = re_mainname.search(data).group(1)
  90        sub_rev = re_rev.search(data).group(1)
  91     fmt = 'LYS_YANG'
  92
  93 if name is None or rev is None:
  94     raise ValueError('cannot determine YANG module name and revision')
  95
  96 lines = [escape(row) for row in data.split('\n')]
  97 text = '\\n"\n\t"'.join(lines)
  98
  99 with open(outname, 'w') as fd:
 100     fd.write(template % (text, escape(name), escape(rev), escape(sub_name), escape(sub_rev), fmt))