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