xref: /openbmc/qemu/scripts/tracetool/__init__.py (revision 6e2e2e8a) 
1# -*- coding: utf-8 -*-
2
3"""
4Machinery for generating tracing-related intermediate files.
5"""
6
7__author__     = "Lluís Vilanova <vilanova@ac.upc.edu>"
8__copyright__  = "Copyright 2012-2017, Lluís Vilanova <vilanova@ac.upc.edu>"
9__license__    = "GPL version 2 or (at your option) any later version"
10
11__maintainer__ = "Stefan Hajnoczi"
12__email__      = "stefanha@redhat.com"
13
14
15import re
16import sys
17import weakref
18
19import tracetool.format
20import tracetool.backend
21import tracetool.transform
22
23
24def error_write(*lines):
25    """Write a set of error lines."""
26    sys.stderr.writelines("\n".join(lines) + "\n")
27
28def error(*lines):
29    """Write a set of error lines and exit."""
30    error_write(*lines)
31    sys.exit(1)
32
33
34def out(*lines, **kwargs):
35    """Write a set of output lines.
36
37    You can use kwargs as a shorthand for mapping variables when formatting all
38    the strings in lines.
39    """
40    lines = [ l % kwargs for l in lines ]
41    sys.stdout.writelines("\n".join(lines) + "\n")
42
43# We only want to allow standard C types or fixed sized
44# integer types. We don't want QEMU specific types
45# as we can't assume trace backends can resolve all the
46# typedefs
47ALLOWED_TYPES = [
48    "int",
49    "long",
50    "short",
51    "char",
52    "bool",
53    "unsigned",
54    "signed",
55    "int8_t",
56    "uint8_t",
57    "int16_t",
58    "uint16_t",
59    "int32_t",
60    "uint32_t",
61    "int64_t",
62    "uint64_t",
63    "void",
64    "size_t",
65    "ssize_t",
66    "uintptr_t",
67    "ptrdiff_t",
68    # Magic substitution is done by tracetool
69    "TCGv",
70]
71
72def validate_type(name):
73    bits = name.split(" ")
74    for bit in bits:
75        bit = re.sub("\*", "", bit)
76        if bit == "":
77            continue
78        if bit == "const":
79            continue
80        if bit not in ALLOWED_TYPES:
81            raise ValueError("Argument type '%s' is not in whitelist. "
82                             "Only standard C types and fixed size integer "
83                             "types should be used. struct, union, and "
84                             "other complex pointer types should be "
85                             "declared as 'void *'" % name)
86
87class Arguments:
88    """Event arguments description."""
89
90    def __init__(self, args):
91        """
92        Parameters
93        ----------
94        args :
95            List of (type, name) tuples or Arguments objects.
96        """
97        self._args = []
98        for arg in args:
99            if isinstance(arg, Arguments):
100                self._args.extend(arg._args)
101            else:
102                self._args.append(arg)
103
104    def copy(self):
105        """Create a new copy."""
106        return Arguments(list(self._args))
107
108    @staticmethod
109    def build(arg_str):
110        """Build and Arguments instance from an argument string.
111
112        Parameters
113        ----------
114        arg_str : str
115            String describing the event arguments.
116        """
117        res = []
118        for arg in arg_str.split(","):
119            arg = arg.strip()
120            if not arg:
121                raise ValueError("Empty argument (did you forget to use 'void'?)")
122            if arg == 'void':
123                continue
124
125            if '*' in arg:
126                arg_type, identifier = arg.rsplit('*', 1)
127                arg_type += '*'
128                identifier = identifier.strip()
129            else:
130                arg_type, identifier = arg.rsplit(None, 1)
131
132            validate_type(arg_type)
133            res.append((arg_type, identifier))
134        return Arguments(res)
135
136    def __getitem__(self, index):
137        if isinstance(index, slice):
138            return Arguments(self._args[index])
139        else:
140            return self._args[index]
141
142    def __iter__(self):
143        """Iterate over the (type, name) pairs."""
144        return iter(self._args)
145
146    def __len__(self):
147        """Number of arguments."""
148        return len(self._args)
149
150    def __str__(self):
151        """String suitable for declaring function arguments."""
152        if len(self._args) == 0:
153            return "void"
154        else:
155            return ", ".join([ " ".join([t, n]) for t,n in self._args ])
156
157    def __repr__(self):
158        """Evaluable string representation for this object."""
159        return "Arguments(\"%s\")" % str(self)
160
161    def names(self):
162        """List of argument names."""
163        return [ name for _, name in self._args ]
164
165    def types(self):
166        """List of argument types."""
167        return [ type_ for type_, _ in self._args ]
168
169    def casted(self):
170        """List of argument names casted to their type."""
171        return ["(%s)%s" % (type_, name) for type_, name in self._args]
172
173    def transform(self, *trans):
174        """Return a new Arguments instance with transformed types.
175
176        The types in the resulting Arguments instance are transformed according
177        to tracetool.transform.transform_type.
178        """
179        res = []
180        for type_, name in self._args:
181            res.append((tracetool.transform.transform_type(type_, *trans),
182                        name))
183        return Arguments(res)
184
185
186class Event(object):
187    """Event description.
188
189    Attributes
190    ----------
191    name : str
192        The event name.
193    fmt : str
194        The event format string.
195    properties : set(str)
196        Properties of the event.
197    args : Arguments
198        The event arguments.
199
200    """
201
202    _CRE = re.compile("((?P<props>[\w\s]+)\s+)?"
203                      "(?P<name>\w+)"
204                      "\((?P<args>[^)]*)\)"
205                      "\s*"
206                      "(?:(?:(?P<fmt_trans>\".+),)?\s*(?P<fmt>\".+))?"
207                      "\s*")
208
209    _VALID_PROPS = set(["disable", "tcg", "tcg-trans", "tcg-exec", "vcpu"])
210
211    def __init__(self, name, props, fmt, args, orig=None,
212                 event_trans=None, event_exec=None):
213        """
214        Parameters
215        ----------
216        name : string
217            Event name.
218        props : list of str
219            Property names.
220        fmt : str, list of str
221            Event printing format string(s).
222        args : Arguments
223            Event arguments.
224        orig : Event or None
225            Original Event before transformation/generation.
226        event_trans : Event or None
227            Generated translation-time event ("tcg" property).
228        event_exec : Event or None
229            Generated execution-time event ("tcg" property).
230
231        """
232        self.name = name
233        self.properties = props
234        self.fmt = fmt
235        self.args = args
236        self.event_trans = event_trans
237        self.event_exec = event_exec
238
239        if len(args) > 10:
240            raise ValueError("Event '%s' has more than maximum permitted "
241                             "argument count" % name)
242
243        if orig is None:
244            self.original = weakref.ref(self)
245        else:
246            self.original = orig
247
248        unknown_props = set(self.properties) - self._VALID_PROPS
249        if len(unknown_props) > 0:
250            raise ValueError("Unknown properties: %s"
251                             % ", ".join(unknown_props))
252        assert isinstance(self.fmt, str) or len(self.fmt) == 2
253
254    def copy(self):
255        """Create a new copy."""
256        return Event(self.name, list(self.properties), self.fmt,
257                     self.args.copy(), self, self.event_trans, self.event_exec)
258
259    @staticmethod
260    def build(line_str):
261        """Build an Event instance from a string.
262
263        Parameters
264        ----------
265        line_str : str
266            Line describing the event.
267        """
268        m = Event._CRE.match(line_str)
269        assert m is not None
270        groups = m.groupdict('')
271
272        name = groups["name"]
273        props = groups["props"].split()
274        fmt = groups["fmt"]
275        fmt_trans = groups["fmt_trans"]
276        if fmt.find("%m") != -1 or fmt_trans.find("%m") != -1:
277            raise ValueError("Event format '%m' is forbidden, pass the error "
278                             "as an explicit trace argument")
279        if fmt.endswith(r'\n"'):
280            raise ValueError("Event format must not end with a newline "
281                             "character")
282
283        if len(fmt_trans) > 0:
284            fmt = [fmt_trans, fmt]
285        args = Arguments.build(groups["args"])
286
287        if "tcg-trans" in props:
288            raise ValueError("Invalid property 'tcg-trans'")
289        if "tcg-exec" in props:
290            raise ValueError("Invalid property 'tcg-exec'")
291        if "tcg" not in props and not isinstance(fmt, str):
292            raise ValueError("Only events with 'tcg' property can have two format strings")
293        if "tcg" in props and isinstance(fmt, str):
294            raise ValueError("Events with 'tcg' property must have two format strings")
295
296        event = Event(name, props, fmt, args)
297
298        # add implicit arguments when using the 'vcpu' property
299        import tracetool.vcpu
300        event = tracetool.vcpu.transform_event(event)
301
302        return event
303
304    def __repr__(self):
305        """Evaluable string representation for this object."""
306        if isinstance(self.fmt, str):
307            fmt = self.fmt
308        else:
309            fmt = "%s, %s" % (self.fmt[0], self.fmt[1])
310        return "Event('%s %s(%s) %s')" % (" ".join(self.properties),
311                                          self.name,
312                                          self.args,
313                                          fmt)
314    # Star matching on PRI is dangerous as one might have multiple
315    # arguments with that format, hence the non-greedy version of it.
316    _FMT = re.compile("(%[\d\.]*\w+|%.*?PRI\S+)")
317
318    def formats(self):
319        """List conversion specifiers in the argument print format string."""
320        assert not isinstance(self.fmt, list)
321        return self._FMT.findall(self.fmt)
322
323    QEMU_TRACE               = "trace_%(name)s"
324    QEMU_TRACE_NOCHECK       = "_nocheck__" + QEMU_TRACE
325    QEMU_TRACE_TCG           = QEMU_TRACE + "_tcg"
326    QEMU_DSTATE              = "_TRACE_%(NAME)s_DSTATE"
327    QEMU_BACKEND_DSTATE      = "TRACE_%(NAME)s_BACKEND_DSTATE"
328    QEMU_EVENT               = "_TRACE_%(NAME)s_EVENT"
329
330    def api(self, fmt=None):
331        if fmt is None:
332            fmt = Event.QEMU_TRACE
333        return fmt % {"name": self.name, "NAME": self.name.upper()}
334
335    def transform(self, *trans):
336        """Return a new Event with transformed Arguments."""
337        return Event(self.name,
338                     list(self.properties),
339                     self.fmt,
340                     self.args.transform(*trans),
341                     self)
342
343
344def read_events(fobj, fname):
345    """Generate the output for the given (format, backends) pair.
346
347    Parameters
348    ----------
349    fobj : file
350        Event description file.
351    fname : str
352        Name of event file
353
354    Returns a list of Event objects
355    """
356
357    events = []
358    for lineno, line in enumerate(fobj, 1):
359        if line[-1] != '\n':
360            raise ValueError("%s does not end with a new line" % fname)
361        if not line.strip():
362            continue
363        if line.lstrip().startswith('#'):
364            continue
365
366        try:
367            event = Event.build(line)
368        except ValueError as e:
369            arg0 = 'Error at %s:%d: %s' % (fname, lineno, e.args[0])
370            e.args = (arg0,) + e.args[1:]
371            raise
372
373        # transform TCG-enabled events
374        if "tcg" not in event.properties:
375            events.append(event)
376        else:
377            event_trans = event.copy()
378            event_trans.name += "_trans"
379            event_trans.properties += ["tcg-trans"]
380            event_trans.fmt = event.fmt[0]
381            # ignore TCG arguments
382            args_trans = []
383            for atrans, aorig in zip(
384                    event_trans.transform(tracetool.transform.TCG_2_HOST).args,
385                    event.args):
386                if atrans == aorig:
387                    args_trans.append(atrans)
388            event_trans.args = Arguments(args_trans)
389
390            event_exec = event.copy()
391            event_exec.name += "_exec"
392            event_exec.properties += ["tcg-exec"]
393            event_exec.fmt = event.fmt[1]
394            event_exec.args = event_exec.args.transform(tracetool.transform.TCG_2_HOST)
395
396            new_event = [event_trans, event_exec]
397            event.event_trans, event.event_exec = new_event
398
399            events.extend(new_event)
400
401    return events
402
403
404class TracetoolError (Exception):
405    """Exception for calls to generate."""
406    pass
407
408
409def try_import(mod_name, attr_name=None, attr_default=None):
410    """Try to import a module and get an attribute from it.
411
412    Parameters
413    ----------
414    mod_name : str
415        Module name.
416    attr_name : str, optional
417        Name of an attribute in the module.
418    attr_default : optional
419        Default value if the attribute does not exist in the module.
420
421    Returns
422    -------
423    A pair indicating whether the module could be imported and the module or
424    object or attribute value.
425    """
426    try:
427        module = __import__(mod_name, globals(), locals(), ["__package__"])
428        if attr_name is None:
429            return True, module
430        return True, getattr(module, str(attr_name), attr_default)
431    except ImportError:
432        return False, None
433
434
435def generate(events, group, format, backends,
436             binary=None, probe_prefix=None):
437    """Generate the output for the given (format, backends) pair.
438
439    Parameters
440    ----------
441    events : list
442        list of Event objects to generate for
443    group: str
444        Name of the tracing group
445    format : str
446        Output format name.
447    backends : list
448        Output backend names.
449    binary : str or None
450        See tracetool.backend.dtrace.BINARY.
451    probe_prefix : str or None
452        See tracetool.backend.dtrace.PROBEPREFIX.
453    """
454    # fix strange python error (UnboundLocalError tracetool)
455    import tracetool
456
457    format = str(format)
458    if len(format) == 0:
459        raise TracetoolError("format not set")
460    if not tracetool.format.exists(format):
461        raise TracetoolError("unknown format: %s" % format)
462
463    if len(backends) == 0:
464        raise TracetoolError("no backends specified")
465    for backend in backends:
466        if not tracetool.backend.exists(backend):
467            raise TracetoolError("unknown backend: %s" % backend)
468    backend = tracetool.backend.Wrapper(backends, format)
469
470    import tracetool.backend.dtrace
471    tracetool.backend.dtrace.BINARY = binary
472    tracetool.backend.dtrace.PROBEPREFIX = probe_prefix
473
474    tracetool.format.generate(events, format, backend, group)
475