On Oct 23, 2009, at 8:55 AM, Max wrote:
Hi Folks,
I'm trying to get to grips with dapptrace, running it on my Mac.
Everything seems pretty straightforward, except for - of course -
what I'm trying to do.
I want to focus in on my code but I can't seem to be able to output
just the functions I want, i.e. user functions.
The -U option gives everything. Too much of course.
Leaving that blank means the default which seems to be "a.out",
e.g. sudo -s dapptrace ~/myexecutable
: probe description pid31688:a.out::entry does not match any probes
That hits nothing.
If I take a lib from all the output using the -U option, e.g.
libSystem.B.dylib,
-> libSystem.B.dylib:free(0x300D70, 0x1A, 0xBFFFF258)
-> libSystem.B.dylib:szone_size(0x22E000, 0x300D70, 0x50)
<- libSystem.B.dylib:szone_size = 585
-> libSystem.B.dylib:szone_free_definite_size(0x22E000, 0x300D70,
0x10)
-> libSystem.B.dylib:tiny_free_list_remove_ptr(0x1, 0x231500,
0x22E000)
<- libSystem.B.dylib:tiny_free_list_remove_ptr = 239
<- libSystem.B.dylib:szone_free_de
and try that specifying the -u option as in:
sudo -s dapptrace -u libSystem.B.dylib ~/myexecutable
that gives...
: probe description pid31696:libSystem.B.dylib::entry does not
match any probes
which to me is weird as that is a library it is showing when I run
with the -U option.
I think I'm missing something obvious here and any advice would be
much appreciated.
Max,
The problem is that the dapptrace script is doing this:
### Run DTrace
if [ $opt_command -eq 1 ]; then
/usr/sbin/dtrace -x dynvarsize=$buf -x evaltime=exec -n "$dtrace" \
-c "$command" >&2
else
/usr/sbin/dtrace -x dynvarsize=$buf -n "$dtrace" -p "$pid" >&2
fi
The -x evaltime=exec option means "start tracing immediately when the
app is launched",
but at that time, the only libraries loaded are dyld and the target
executable. There really
aren't any libSystem.B.dylib functions to probe.
If you add a "-Z" after the -x evaltime=exec above, your command
should work.
I'm not sure what is going on with a.out not working, I believe it
should work,
and it is a bug that it isn't.
James M
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