Re: [PATCH] hurd: Add enough auxv support for AT_ENTRY for PIE binaries

[Simon Marchi <simark@simark.ca>]

On 2017-12-28 16:27, Samuel Thibault wrote:
> Hello,
> 
> Simon Marchi, on mer. 27 déc. 2017 21:19:12 -0500, wrote:
>> If nobody has commented by the time we are
>> ready to create the 8.1 branch (supposed to be in January), we'll
>> merge it.  I'll add a note to the GDB 8.1 release wiki page [1] so
>> we don't forget.  Does that sound good to you?
> 
> Sure.
> 
>> In the mean time, I'd like to add some details to the commit message
>> about how this is expected to work.  The AT_ENTRY value set here
>> will be read by the svr4_exec_displacement function, is that right?
> 
> Yes, here is the backtrace:
> 
> #0  gnu_xfer_partial (ops=0x867cb78, object=TARGET_OBJECT_AUXV,
> annex=0x0, readbuf=0x8787250 "", writebuf=0x0, offset=0, len=4096,
> xfered_len=0x28043e0) at ./gdb/gnu-nat.c:2615
> #1  0x081f09a7 in target_xfer_partial (ops=0x863d440 <current_target>,
> object=TARGET_OBJECT_AUXV, annex=0x0, readbuf=0x8787250 "",
> writebuf=0x0, offset=0, len=<optimized out>, xfered_len=0x28043e0) at
> ./gdb/target.c:1374
> #2  0x081f0e32 in target_read_partial (xfered_len=0x28043e0, len=4096,
> offset=0, buf=0x8787250 "", annex=0x0, object=TARGET_OBJECT_AUXV,
> ops=0x863d440 <current_target>) at ./gdb/target.c:1619
> #3  target_read_alloc_1 (ops=0x863d440 <current_target>,
> object=TARGET_OBJECT_AUXV, annex=annex@entry=0x0, buf_p=0x87721e8,
> padding=0) at ./gdb/target.c:1988
> #4  0x081f1f21 in target_read_alloc (ops=<optimized out>,
> object=<optimized out>, annex=0x0, buf_p=0x87721e8) at
> ./gdb/target.c:2029
> #5  0x0812022f in get_auxv_inferior_data (ops=ops@entry=0x863d440
> <current_target>) at ./gdb/auxv.c:362
> #6  0x081206a1 in target_auxv_search (ops=0x863d440 <current_target>,
> match=9, valp=0x28044d0) at ./gdb/auxv.c:382
> #7  0x08068c7f in svr4_exec_displacement (displacementp=<synthetic
> pointer>) at ./gdb/solib-svr4.c:2649
> #8  svr4_relocate_main_executable () at ./gdb/solib-svr4.c:3031
> #9  0x0806a828 in svr4_solib_create_inferior_hook (from_tty=0) at
> ./gdb/solib-svr4.c:3092
> #10 0x0819490b in post_create_inferior (target=<optimized out>,
> from_tty=<optimized out>) at ./gdb/infcmd.c:445
> #11 0x08194c5f in run_command_1 (args=<optimized out>, from_tty=1,
> tbreak_at_main=<optimized out>) at ./gdb/infcmd.c:631
> ...
> 
> Samuel

Hi Samuel,

I pushed this patch to master and gdb-8.1-branch.

Thanks,

Simon