Re: [rfc] Fix PR 18208: update /proc/pid/coredump_filter by c code

[Luis Machado <lgustavo@codesourcery.com>]

On 05/06/2015 01:12 PM, Pedro Alves wrote:
> On 04/24/2015 04:28 PM, Yao Qi wrote:
>
>> We see some fails in gdb.base/coredump-filter.exp when we do remote
>> gdbserver testing, like what I did for arm/aarch64 linux testing or
>> run it with board file remote-gdbserver-on-localhost
>>
>>   $ make check RUNTESTFLAGS='--target_board=remote-gdbserver-on-localhost coredump-filter.exp'
>>
>> we find that this line in the test doesn't work as expected,
>>
>>   remote_exec target "sh -c \"echo $filter_flag > /proc/$ipid/coredump_filter\""
>>
>> although such pattern has been used in gdb testsuite somewhere else,
>> but the special thing here is that we redirect the output to
>> /proc/$ipid/coredump_filter on the remote target.  DejaGNU will
>> redirect the output from the remote target to local, and looks tcl
>> gets confused by these two redirection.
>
> Not sure what exactly gets confused either.
>
>>
>> After trying pass different parameters to remote_exec and hacking
>> remote_exec/rsh_exec/local_exec, I got no success, I decide
>> to give up, and try to update /proc/$ipid/coredump_filter by the c
>> code directly.
>
> Probably the right fix would be for dejagnu to put ''s around
> the whole sh -c command in rsh_exec:
>
>      set ret [local_exec "$RSH $rsh_useropts $hostname sh -c '$program $pargs \\; echo XYZ\\\${?}ZYX'" $inp $outp $timeout]
>
> dunno if that would work with real rsh.  Alternatively, teach
> dejagnu about a real ssh mode...
>
>>
>> This patch adds a c function set_coredump_filter to update
>> coredump_filter, and GDB calls it.
>>
>
> This is fine with me.
>
>> Now this test passes on boardfile unix, native-gdbserver and
>> remote-gdbserver-on-localhost.  It also passes my board files for arm
>> and aarch64 testing.
>
>
>>       # Generate a corefile.
>>       gdb_gcore_cmd "$core" "save corefile"
>> @@ -146,11 +146,8 @@ if { !$core_supported } {
>>       return -1
>>   }
>>
>> -# Get the inferior's PID.
>> -set infpid ""
>>   gdb_test_multiple "info inferiors" "getting inferior pid" {
>> -    -re "process \($decimal\).*\r\n$gdb_prompt $" {
>> -	set infpid $expect_out(1,string)
>> +    -re "process $decimal.*\r\n$gdb_prompt $" {
>>       }
>>       -re "Remote target.*$gdb_prompt $" {
>>   	# If the target does not provide PID information (like usermode QEMU),
>
> This "If the target does not provide PID information" check sounds
> odd now.  Do we still need it?

If we're not dealing with PID's, i don't think so.