Re: [PATCH v2 3/4] gdb: testsuite: use gdb_attach to fix attach-pie-noexec.exp

[Simon Marchi <simon.marchi@polymtl.ca>]

On 2022-03-17 00:43, Tiezhu Yang wrote:
> If /proc/sys/kernel/yama/ptrace_scope is 1, when execute the following
> command without superuser:
> 
>   make check-gdb TESTS="gdb.base/attach-pie-noexec.exp"
> 
> we can see the following messages in gdb/testsuite/gdb.log:
> 
>   (gdb) attach 6500
>   Attaching to process 6500
>   ptrace: Operation not permitted.
>   (gdb) PASS: gdb.base/attach-pie-noexec.exp: attach
> 
> It is obviously wrong, the expected result should be UNSUPPORTED in such
> a case.
> 
> With this patch, we can see "Operation not permitted" in the log info,
> and then we can do the following processes to test:
> (1) set ptrace_scope as 0
>     $ echo 0 | sudo tee /proc/sys/kernel/yama/ptrace_scope
>     $ make check-gdb TESTS="gdb.base/attach-pie-noexec.exp"
> (2) use sudo
>     $ sudo make check-gdb TESTS="gdb.base/attach-pie-noexec.exp"
> 
> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
> ---
>  gdb/testsuite/gdb.base/attach-pie-noexec.exp | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/gdb/testsuite/gdb.base/attach-pie-noexec.exp b/gdb/testsuite/gdb.base/attach-pie-noexec.exp
> index 4712824..9a1bafe 100644
> --- a/gdb/testsuite/gdb.base/attach-pie-noexec.exp
> +++ b/gdb/testsuite/gdb.base/attach-pie-noexec.exp
> @@ -59,7 +59,9 @@ set testpid [spawn_id_get_pid $test_spawn_id]
>  
>  gdb_start
>  file delete -- $binfile
> -gdb_test "attach $testpid" "Attaching to process $testpid\r\n.*" "attach"
> +if {![gdb_attach $testpid]} {
> +    return 0
> +}

You can do just "return", I don't think that return value is used
anywhere.

LGTM with that.

Simon