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
  54
  55 def escapech(char):
  56     if char in passchars:
  57         return char
  58     if char == "\n":
  59         return "\\n"
  60     if char == "\t":
  61         return "\\t"
  62     if char in "\"\\'":
  63         return "\\" + char
  64     return "\\x%02x" % (ord(char))
  65
  66
  67 def escape(line):
  68     return "".join([escapech(i) for i in line])
  69
  70
  71 with open(inname, "r") as fd:
  72     data = fd.read()
  73
  74 sub_name = ""
  75 rev = ""
  76 sub_rev = ""
  77
  78 # XML support isn't actively used currently, but it's here in case the need
  79 # arises.  It does avoid the regex'ing.
  80 if "<?xml" in data:
  81     from xml.etree import ElementTree
  82
  83     xml = ElementTree.fromstring(data)
  84     name = xml.get("name")
  85     rev = xml.find("{urn:ietf:params:xml:ns:yang:yin:1}revision").get("date")
  86     fmt = "LYS_YIN"
  87 else:
  88     search_name = re_name.search(data)
  89     if search_name:
  90         name = search_name.group(1)
  91         rev = re_rev.search(data).group(1)
  92     else:
  93         search_name = re_subname.search(data)
  94         sub_name = search_name.group(1)
  95         name = re_mainname.search(data).group(1)
  96         sub_rev = re_rev.search(data).group(1)
  97     fmt = "LYS_IN_YANG"
  98
  99 if name is None or rev is None:
 100     raise ValueError("cannot determine YANG module name and revision")
 101
 102 lines = [escape(row) for row in data.split("\n")]
 103 text = '\\n"\n\t"'.join(lines)
 104
 105 with open(outname, "w") as fd:
 106     fd.write(
 107         template
 108         % (text, escape(name), escape(rev), escape(sub_name), escape(sub_rev), fmt)
 109     )