Re: [Qemu-devel] [PATCH] trace: tighten up trace-events regex to fix bad parse

[Stefan Hajnoczi <stefanha@redhat.com>]

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On Mon, Sep 22, 2014 at 12:35:22PM -0500, Lluís Vilanova wrote:
> Stefan Hajnoczi writes:
> 
> > Use \w for properties and trace event names since they are both drawn
> > from [a-zA-Z0-9_] character sets.
> 
> > The .* for matching properties was too aggressive and caused the
> > following failure with foo(int rc) "(this is a test)":
> 
> >   Traceback (most recent call last):
> >     File "scripts/tracetool.py", line 139, in <module>
> >       main(sys.argv)
> >     File "scripts/tracetool.py", line 134, in main
> >       binary=binary, probe_prefix=probe_prefix)
> >     File "scripts/tracetool/__init__.py", line 334, in generate
> >       events = _read_events(fevents)
> >     File "scripts/tracetool/__init__.py", line 262, in _read_events
> >       res.append(Event.build(line))
> >     File "scripts/tracetool/__init__.py", line 225, in build
> >       return Event(name, props, fmt, args, arg_fmts)
> >     File "scripts/tracetool/__init__.py", line 185, in __init__
> >       % ", ".join(unknown_props))
> >   ValueError: Unknown properties: foo(int, rc)
> 
> > Cc: Lluís Vilanova <vilanova@ac.upc.edu>
> > Reported-by: Eric Auger <eric.auger@linaro.org>
> > Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> > ---
> >  scripts/tracetool/__init__.py | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> > diff --git a/scripts/tracetool/__init__.py b/scripts/tracetool/__init__.py
> > index 36c789d..474f11b 100644
> > --- a/scripts/tracetool/__init__.py
> > +++ b/scripts/tracetool/__init__.py
> > @@ -140,8 +140,8 @@ class Event(object):
> >          The format strings for each argument.
> >      """
>  
> > -    _CRE = re.compile("((?P<props>.*)\s+)?"
> > -                      "(?P<name>[^(\s]+)"
> > +    _CRE = re.compile("((?P<props>\w*)\s+)?"
> > +                      "(?P<name>\w+)"
> >                        "\((?P<args>[^)]*)\)"
> >                        "\s*"
> >                        "(?:(?:(?P<fmt_trans>\".+),)?\s*(?P<fmt>\".+))?"
> 
> The previous implementation allowed multiple properties. Maybe this should be
> instead (which still allows multiple properties):
> 
>     "((?P<props>[\w\s]+)\s+)?"
>     "(?P<name>\w+)\s*"
>     ...

Ooops, good point!

I will send v2.

Stefan

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