1#!/usr/bin/env python
2# -*- coding: utf-8 -*-
3
4"""
5Generate .stp file that outputs simpletrace binary traces (DTrace with SystemTAP only).
6"""
7
8__author__     = "Stefan Hajnoczi <redhat.com>"
9__copyright__  = "Copyright (C) 2014, Red Hat, Inc."
10__license__    = "GPL version 2 or (at your option) any later version"
11
12__maintainer__ = "Stefan Hajnoczi"
13__email__      = "stefanha@redhat.com"
14
15
16from tracetool import out
17from tracetool.backend.dtrace import binary, probeprefix
18from tracetool.backend.simple import is_string
19from tracetool.format.stap import stap_escape
20
21def global_var_name(name):
22    return probeprefix().replace(".", "_") + "_" + name
23
24def generate(events, backend, group):
25    id_map = global_var_name("event_name_to_id_map")
26    next_id = global_var_name("event_next_id")
27    map_func = global_var_name("simple_trace_map_event")
28    out('/* This file is autogenerated by tracetool, do not edit. */',
29        '',
30        'global %(id_map)s',
31        'global %(next_id)s',
32        'function %(map_func)s(name)',
33        '',
34        '{',
35        '    if (!([name] in %(id_map)s)) {',
36        '        %(id_map)s[name] = %(next_id)s',
37        '        name_len = strlen(name)',
38        '        printf("%%8b%%8b%%4b%%.*s", 0, ',
39        '               %(next_id)s, name_len, name_len, name)',
40        '        %(next_id)s = %(next_id)s + 1',
41        '    }',
42        '    return %(id_map)s[name]',
43        '}',
44        'probe begin',
45        '{',
46        '    printf("%%8b%%8b%%8b", 0xffffffffffffffff, 0xf2b177cb0aa429b4, 4)',
47        '}',
48        '',
49        id_map=id_map,
50        next_id=next_id,
51        map_func=map_func)
52
53    for event_id, e in enumerate(events):
54        if 'disable' in e.properties:
55            continue
56
57        out('probe %(probeprefix)s.simpletrace.%(name)s = %(probeprefix)s.%(name)s ?',
58            '{',
59            '    id = %(map_func)s("%(name)s")',
60            probeprefix=probeprefix(),
61            map_func=map_func,
62            name=e.name)
63
64        # Calculate record size
65        sizes = ['24'] # sizeof(TraceRecord)
66        for type_, name in e.args:
67            name = stap_escape(name)
68            if is_string(type_):
69                out('    try {',
70                    '        arg%(name)s_str = %(name)s ? user_string_n(%(name)s, 512) : "<null>"',
71                    '    } catch {}',
72                    '    arg%(name)s_len = strlen(arg%(name)s_str)',
73                    name=name)
74                sizes.append('4 + arg%s_len' % name)
75            else:
76                sizes.append('8')
77        sizestr = ' + '.join(sizes)
78
79        # Generate format string and value pairs for record header and arguments
80        fields = [('8b', 'id'),
81                  ('8b', 'gettimeofday_ns()'),
82                  ('4b', sizestr),
83                  ('4b', 'pid()')]
84        for type_, name in e.args:
85            name = stap_escape(name)
86            if is_string(type_):
87                fields.extend([('4b', 'arg%s_len' % name),
88                               ('.*s', 'arg%s_len, arg%s_str' % (name, name))])
89            else:
90                fields.append(('8b', name))
91
92        # Emit the entire record in a single SystemTap printf()
93        fmt_str = '%'.join(fmt for fmt, _ in fields)
94        arg_str = ', '.join(arg for _, arg in fields)
95        out('    printf("%%8b%%%(fmt_str)s", 1, %(arg_str)s)',
96            fmt_str=fmt_str, arg_str=arg_str)
97
98        out('}')
99
100    out()
101