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RE: rebase addon - Bas and Size listing of dll's without rebasing


> > On Fri, Dec 28, 2001 at 12:50:07PM +0100, Ralf Habacker wrote:
> > >> -----Original Message-----
> > >> From: Jason Tishler [mailto:jason@tishler.net]
> > >> On Wed, Dec 26, 2001 at 09:08:49PM +0100, Ralf Habacker wrote:
> > >> > On analysing this problem I added an option "-l" to the rebase tool to
> > >> > list dll's imagebase and -size without rebasing. It's very interesting
> > >> > to see how MS chooses there Imagebase.
> > >>
> > >> What about the following alternative solution:
> > >>
> > >>     $ objdump -p foo.dll | egrep '(ImageBase|SizeOfImage)'
> > >>     ImageBase               68000000
> > >>     SizeOfImage             0003f000
> > >
> > >Try it with a recent objdump and a dll with auto-import variables and you will see that
> > >objdump crashes. :-(
> >
> > Seems to work fine with the distributed version of binutils.  I tried
> > this with cygncurses6.dll.

Yes this work, because this lib provides an auto-importable var. But try a lib which depends
on this lib, than objdump will fail with a segment violation.
This is an example from cygkdecore-3.dll (the kdecore dll of kde 2.2.1) which uses
qt-2.3.dll, which exports such auto-importable vars
....
 001530b4       0017dfd4 00000000 00000000 0018814c 00002b13

        DLL Name: qt-2-3.dll
        vma:  Hint/Ord Member-Name
        180554    842  _7QString$null

Program received signal SIGSEGV, Segmentation fault.
bfd_getl32 (addr=0xa011928 "\"") at libbfd.c:1059
1059    libbfd.c: No such file or directory.
        in libbfd.c
(gdb) bt
#0  bfd_getl32 (addr=0xa011928 "\"") at libbfd.c:1059
#1  0x0045bccf in _bfd_pe_print_private_bfd_data_common (abfd=0xa011928,
    vfile=0x6109f25c) at peigen.c:1846
#2  0x0043cc94 in pe_print_private_bfd_data (abfd=0xa011928, vfile=0x6109f25c)
    at peicode.h:365
#3  0x0040557d in dump_bfd_private_header (abfd=0xa011928) at ./objdump.c:2029
#4  0x00405693 in dump_bfd (abfd=0xa011928) at ./objdump.c:2059
#5  0x0040591c in display_bfd (abfd=0xa011928) at ./objdump.c:2140
#6  0x00405a75 in display_file (
    filename=0x22feae "/opt/kde2/bin/cygkdecore-3.dll", target=0x0)
    at ./objdump.c:2195
#7  0x004074a6 in main (argc=3, argv=0xa0118c8) at ./objdump.c:2942
#8  0x61003f6e in dll_crt0_1 () at ../../../src/winsup/cygwin/dcrt0.cc:769
#9  0x61004262 in _dll_crt0 () at ../../../src/winsup/cygwin/dcrt0.cc:863
#10 0x610042a1 in dll_crt0 (uptr=0x0)
    at ../../../src/winsup/cygwin/dcrt0.cc:876
#11 0x00487bcf in cygwin_crt0 ()
#12 0x0040103d in mainCRTStartup ()
#13 0x77e892a6 in _system_dlls__ ()

0xa011928:      0x0022feae
0xa01192c:      0x00440fd4
0xa011930:      0x0a011764
0xa011934:      0x00000001
0xa011938:      0x00000001
0xa01193c:      0x0a011928
0xa011940:      0x0a011928
0xa011944:      0x00184600
0xa011948:      0x00000000
0xa01194c:      0x00000000
0xa011950:      0x00000000
0xa011954:      0x00000000
0xa011958:      0x00000001
0xa01195c:      0x00000001
0xa011960:      0x00000133
0xa011964:      0x00000000

The following is an extract of a debugging session.

(gdb) c
Continuing.
        The Import Address Table is identical

 001530b4       0017dfd4 00000000 00000000 0018814c 00002b13

        DLL Name: qt-2-3.dll
        vma:  Hint/Ord Member-Name
        180554    842  _7QString$null
Breakpoint 6, pe_print_idata (abfd=0xa011928, vfile=0x6109f25c)
    at peigen.c:1222
1222          if (hint_addr != first_thunk && time_stamp == 0)
(gdb) n
1227              idx2 = first_thunk - adj;
(gdb)
1224              int differ = 0;
(gdb)
1227              idx2 = first_thunk - adj;
(gdb)
1229              for (j = 0; j < datasize; j += 4)
(gdb)
1233                  bfd_vma hint_member = 0;
(gdb)
1236                  if (hint_addr != 0)
(gdb)
1237                    hint_member = bfd_get_32 (abfd, data + idx + j);
(gdb)
1238                  iat_member = bfd_get_32 (abfd, data + idx2 + j);
(gdb)
Program received signal SIGSEGV, Segmentation fault.
bfd_getl32 (addr=0xa011928 "\"") at libbfd.c:1059
1059      v |= (unsigned long) addr[1] << 8;

Appended is a little testapp, that shows the bug with ncurses6.

May be that helps identifing the bug.

Regards Ralf

Attachment: objdumptest.tar.bz2
Description: Binary data

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