yang/embedmodel.py

   1 #!/usr/bin/python3
   2 # SPDX-License-Identifier: NONE
   3 #
   4 # YANG module to C wrapper
   5 # written 2018 by David Lamparter, placed in Public Domain.
   6
   7 import sys
   8 import os
   9 import string
  10 import re
  11
  12 inname = sys.argv[1]
  13 outname = sys.argv[2]
  14
  15 outdir = os.path.dirname(os.path.abspath(outname))
  16 try:
  17     os.makedirs(outdir)
  18 except FileExistsError:
  19     pass
  20
  21 # these are regexes to avoid a compile-time/host dependency on yang-tools
  22 # or python-yang.  Cross-compiling FRR is already somewhat involved, no need
  23 # to make it even harder.
  24
  25 re_name = re.compile(r"\bmodule\s+([^\s]+)\s+\{")
  26 re_subname = re.compile(r"\bsubmodule\s+([^\s]+)\s+\{")
  27 re_mainname = re.compile(r"\bbelongs-to\s+([^\s]+)\s+\{")
  28 re_rev = re.compile(r"\brevision\s+([\d-]+)\s+\{")
  29
  30
  31 template = """/* autogenerated by embedmodel.py.  DO NOT EDIT */
  32
  33 #include <zebra.h>
  34 #include "yang.h"
  35
  36 static const char model[] =
  37 \t"%s";
  38
  39 static struct yang_module_embed embed = {
  40 \t.mod_name = "%s",
  41 \t.mod_rev = "%s",
  42 \t.sub_mod_name = "%s",
  43 \t.sub_mod_rev = "%s",
  44 \t.data = model,
  45 \t.format = %s,
  46 };
  47
  48 static void embed_register(void) __attribute__((_CONSTRUCTOR(2000)));
  49 static void embed_register(void)
  50 {
  51 \tyang_module_embed(&embed);
  52 }
  53 """
  54
  55 passchars = set(string.printable) - set("\\'\"%\r\n\t\x0b\x0c")
  56
  57
  58 def escapech(char):
  59     if char in passchars:
  60         return char
  61     if char == "\n":
  62         return "\\n"
  63     if char == "\t":
  64         return "\\t"
  65     if char in "\"\\'":
  66         return "\\" + char
  67     return "\\x%02x" % (ord(char))
  68
  69
  70 def escape(line):
  71     return "".join([escapech(i) for i in line])
  72
  73
  74 with open(inname, "r") as fd:
  75     data = fd.read()
  76
  77 sub_name = ""
  78 rev = ""
  79 sub_rev = ""
  80
  81 # XML support isn't actively used currently, but it's here in case the need
  82 # arises.  It does avoid the regex'ing.
  83 if "<?xml" in data:
  84     from xml.etree import ElementTree
  85
  86     xml = ElementTree.fromstring(data)
  87     name = xml.get("name")
  88     rev = xml.find("{urn:ietf:params:xml:ns:yang:yin:1}revision").get("date")
  89     fmt = "LYS_YIN"
  90 else:
  91     search_name = re_name.search(data)
  92     if search_name:
  93         name = search_name.group(1)
  94         rev = re_rev.search(data).group(1)
  95     else:
  96         search_name = re_subname.search(data)
  97         sub_name = search_name.group(1)
  98         name = re_mainname.search(data).group(1)
  99         sub_rev = re_rev.search(data).group(1)
 100     fmt = "LYS_IN_YANG"
 101
 102 if name is None or rev is None:
 103     raise ValueError("cannot determine YANG module name and revision")
 104
 105 lines = [escape(row) for row in data.split("\n")]
 106 text = '\\n"\n\t"'.join(lines)
 107
 108 with open(outname, "w") as fd:
 109     fd.write(
 110         template
 111         % (text, escape(name), escape(rev), escape(sub_name), escape(sub_rev), fmt)
 112     )