Re: [PATCH] Ignore the first entry returned by svr4_current_sos_via_xfer_libraries for dynamically linked programs

Jan Kratochvil
2013-06-04T20:23:10Z

On Tue, 04 Jun 2013 20:18:10 +0200, Ben Cheng wrote:
> Hmm this problem only shows up after I refresh gdbserver from the
> unmodified gdb 7.6 tree. As you mentioned, gdb 7.1 did not support
> library-list-svr4, so when I paired gdbserver 7.1 with gdb 7.6 they
> also work fine.

In such case there is a bug in FSF gdbserver as it ignores only entries with
name "". Normal glibc uses name "" for the first entry for the executable but
Android Bionic apparently uses "<test_program>" as the first entry instead.

The bug is in gdbserver/linux-low.c linux_qxfer_libraries_svr4() which should
always ignore the first entry, even if it is not "".

The test IGNORE_FIRST does not need to be done there. The check
/* Assume that everything is a library if the dynamic loader was loaded
late by a static executable. */
if (exec_bfd && bfd_get_section_by_name (exec_bfd, ".dynamic") == NULL)

is in fact already done by gdbserver/linux-low.c get_dynamic(): If PT_DYNAMIC
(".dynamic") is not found gdbserver will never send <library-list-svr4/> and
solib-svr4.c falls back to the memory reads where it copes with static
executables fine.

Thanks,
Jan