Re: Remote debugging and dynamic libraries

[Frank Meerkoetter <frank at betaversion dot net>]

Daniel Jacobowitz wrote:

> > i'm trying to remote debug a program running on an arm system running
> > linux but i ran into various problems. If i interrupt the
> > debugged program i can't get symbolic information where it stopped.
> > Also backtraces don't seem to work.
> >
> > frank@linux:~/> /usr/local/bin/arm-linux-gdb
> > GNU gdb 6.3
> > This GDB was configured as "--host=i686-pc-linux-gnu --target=arm-linux".
> > (gdb) target remote 192.168.1.133:5555
> > Remote debugging using 192.168.1.133:5555
> > 0x400028b0 in ?? ()
> > (gdb) symbol-file test
> >    
>
> Don't do this.  Use "file", not "symbol-file".
>
> Can you tell me where you found anything which suggested that you
> should use symbol-file?  This bug is reported several times a year, and
> I still don't know where the incorrect documentation is - I don't think
> it's part of GDB.
>  
You're right. I picked it up in some mailinglist archive while searching for
a solution to my problem.

> Without an "exec file" loaded, which symbol-file does not do, GDB won't
> find the dynamic loader or be able to load shared libraries.
>  
>
> > 1)
> >   set solib-absolute-prefix /usr/local/arm/arm-linux/
> >    
>
> This is the correct way - IFF the directory under that path looks like
> a root filesystem.  If it's laid out like an old-style cross toolchain,
> this may not work.  Paths should match the paths on the target.
>  
I gave it a try using "file test" and
"set solib-absolute-prefix /usr/local/arm/arm-linux/" but had no success 
so far.

frank@linux:~/uclibc_kram/apdf> arm-linux-gdb
GNU gdb 6.3
Copyright 2004 Free Software Foundation, Inc.
This GDB was configured as "--host=i686-pc-linux-gnu --target=arm-linux".
(gdb) file test
Reading symbols from /home/frank/test...done.
(gdb) set solib-absolute-prefix /usr/local/arm/arm-linux/
(gdb) target remote 192.168.1.133:5555
Remote debugging using 192.168.1.133:5555
0x000080e0 in ?? ()
(gdb) l
1       int main() {
2               while(1)
3               {
4                       printf("bla");
5
6               }
7
8       }
(gdb) b 1
Breakpoint 1 at 0x8428: file main.c, line 1.
(gdb) c
Continuing.

Breakpoint 1, main () at main.c:1
1       int main() {
(gdb) n
2               while(1)
(gdb) n
0x0001a12c in ?? ()
(gdb) n
Cannot find bounds of current function
(gdb) n
Cannot find bounds of current function
(gdb) n
Cannot find bounds of current function

(gdb) The program is running.  Exit anyway? (y or n) y
frank@linux:~/uclibc_kram/apdf> arm-linux-gdb
GNU gdb 6.3
Copyright 2004 Free Software Foundation, Inc.
This GDB was configured as "--host=i686-pc-linux-gnu --target=arm-linux".
(gdb)  file test
Reading symbols from /home/frank/test...done.
(gdb) set solib-absolute-prefix /usr/local/arm/arm-linux/
(gdb) target remote 192.168.1.133:5555
Remote debugging using 192.168.1.133:5555
0x000080e0 in ?? ()
(gdb) c
Continuing.

Program received signal SIGINT, Interrupt.
0x000080e0 in ?? ()
(gdb) c
Continuing.

Program received signal SIGINT, Interrupt.
0x000282b4 in ?? ()
(gdb) bt
#0  0x000282b4 in ?? ()

test depends only on the libc and the dynamic linker.
On the target these files are installed in /lib. The GDB
should be able to found them in
/usr/local/arm/arm-linux/lib.

Any ideas how i can solve this problem?

Regards,
 Frank