scripts/tracetool/format/log_stap.py

   1 #!/usr/bin/env python
   2 # -*- coding: utf-8 -*-
   3
   4 """
   5 Generate .stp file that printfs log messages (DTrace with SystemTAP only).
   6 """
   7
   8 __author__     = "Daniel P. Berrange <berrange@redhat.com>"
   9 __copyright__  = "Copyright (C) 2014-2019, Red Hat, Inc."
  10 __license__    = "GPL version 2 or (at your option) any later version"
  11
  12 __maintainer__ = "Daniel Berrange"
  13 __email__      = "berrange@redhat.com"
  14
  15 import re
  16
  17 from tracetool import out
  18 from tracetool.backend.dtrace import binary, probeprefix
  19 from tracetool.backend.simple import is_string
  20 from tracetool.format.stap import stap_escape
  21
  22 def global_var_name(name):
  23     return probeprefix().replace(".", "_") + "_" + name
  24
  25 STATE_SKIP = 0
  26 STATE_LITERAL = 1
  27 STATE_MACRO = 2
  28
  29 def c_macro_to_format(macro):
  30     if macro.startswith("PRI"):
  31         return macro[3]
  32
  33     if macro == "TARGET_FMT_plx":
  34         return "%016x"
  35
  36     raise Exception("Unhandled macro '%s'" % macro)
  37
  38 def c_fmt_to_stap(fmt):
  39     state = 0
  40     bits = []
  41     literal = ""
  42     macro = ""
  43     escape = 0;
  44     for i in range(len(fmt)):
  45         if fmt[i] == '\\':
  46             if escape:
  47                 escape = 0
  48             else:
  49                 escape = 1
  50             if state != STATE_LITERAL:
  51                 raise Exception("Unexpected escape outside string literal")
  52             literal = literal + fmt[i]
  53         elif fmt[i] == '"' and not escape:
  54             if state == STATE_LITERAL:
  55                 state = STATE_SKIP
  56                 bits.append(literal)
  57                 literal = ""
  58             else:
  59                 if state == STATE_MACRO:
  60                     bits.append(c_macro_to_format(macro))
  61                 state = STATE_LITERAL
  62         elif fmt[i] == ' ' or fmt[i] == '\t':
  63             if state == STATE_MACRO:
  64                 bits.append(c_macro_to_format(macro))
  65                 macro = ""
  66                 state = STATE_SKIP
  67             elif state == STATE_LITERAL:
  68                 literal = literal + fmt[i]
  69         else:
  70             escape = 0
  71             if state == STATE_SKIP:
  72                 state = STATE_MACRO
  73
  74             if state == STATE_LITERAL:
  75                 literal = literal + fmt[i]
  76             else:
  77                 macro = macro + fmt[i]
  78
  79     if state == STATE_MACRO:
  80         bits.append(c_macro_to_format(macro))
  81     elif state == STATE_LITERAL:
  82         bits.append(literal)
  83
  84     fmt = re.sub("%(\d*)z(x|u|d)", "%\\1\\2", "".join(bits))
  85     return fmt
  86
  87 def generate(events, backend, group):
  88     out('/* This file is autogenerated by tracetool, do not edit. */',
  89         '')
  90
  91     for event_id, e in enumerate(events):
  92         if 'disable' in e.properties:
  93             continue
  94
  95         out('probe %(probeprefix)s.log.%(name)s = %(probeprefix)s.%(name)s ?',
  96             '{',
  97             probeprefix=probeprefix(),
  98             name=e.name)
  99
 100         # Get references to userspace strings
 101         for type_, name in e.args:
 102             name = stap_escape(name)
 103             if is_string(type_):
 104                 out('    try {',
 105                     '        arg%(name)s_str = %(name)s ? ' +
 106                     'user_string_n(%(name)s, 512) : "<null>"',
 107                     '    } catch {}',
 108                     name=name)
 109
 110         # Determine systemtap's view of variable names
 111         fields = ["pid()", "gettimeofday_ns()"]
 112         for type_, name in e.args:
 113             name = stap_escape(name)
 114             if is_string(type_):
 115                 fields.append("arg" + name + "_str")
 116             else:
 117                 fields.append(name)
 118
 119         # Emit the entire record in a single SystemTap printf()
 120         arg_str = ', '.join(arg for arg in fields)
 121         fmt_str = "%d@%d " + e.name + " " + c_fmt_to_stap(e.fmt) + "\\n"
 122         out('    printf("%(fmt_str)s", %(arg_str)s)',
 123             fmt_str=fmt_str, arg_str=arg_str)
 124
 125         out('}')
 126
 127     out()