Re: Elfutils module reporting

[Nurdin Premji <npremji at redhat dot com>]

Roland McGrath wrote:
> The expected pattern is that you do:
>
> 	dwfl_report_begin
> 	dwfl_report_foo all modules that are in the address space now
> 	dwfl_report_end
>
> i.e., just like with a fresh Dwfl, but dwfl_report_begin instead of dwfl_begin.
> This preserves the existing data structures for modules that haven't
> changed since before dwfl_report_begin, and removes any old modules that
> you didn't report again.  
>
> dwfl_report_begin_add is intended for something like gdb's add-symbol-file,
> where you are always just adding one new thing as opposed to re-synch'ing
> to the new set of mappings after they've changed.  It's just a shorthand
> and mild optimization for re-reporting all the existing modules after
> dwfl_report_begin.
>
> I could add something like a dwfl_report_remove to de-report a reported
> module in a reporting loop (which after dwfl_report_begin_add would be
> equivalent to removing the preexisting module).  But I'd rather exercise
> the interface as it stands a bit more before deciding to add a
> microoptimization.
>
>   
> > I got an assertion failure at the dwfl_report_end stage
> >  /home/yyz/npremji/mainworkspace/frysk/frysk-imports/elfutils/libdwfl/dwfl_module.c:249: 
> > dwfl_report_end: Assertion `i == dwfl->nmodules' failed.
> >     
>
> Please send me a small C test program to reproduce this bug.
>
>
> Thanks,
> Roland
>   
Try this. It was tested against elfutils 0.128 in fedora 7.
#include <libdwfl.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>

int main()
{
static char *flags = "-:.debug:/usr/lib/debug";
Dwfl_Callbacks *cbs = (Dwfl_Callbacks *) malloc(sizeof (Dwfl_Callbacks));
cbs->find_elf = dwfl_linux_proc_find_elf;
cbs->find_debuginfo = dwfl_standard_find_debuginfo;
cbs->debuginfo_path = &flags; 

Dwfl* dwfl = dwfl_begin(cbs);
dwfl_report_begin(dwfl);
dwfl_report_module(dwfl, "module1", 0, 10);
dwfl_report_end(dwfl, NULL, NULL);
dwfl_report_begin(dwfl);
dwfl_report_module(dwfl, "module1", 0, 10);
dwfl_report_end(dwfl, NULL, NULL);
}