Re: [PATCH 3/3] gdb: testsuite: enhance gdb_attach to fix jit-elf.exp

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

On 2022-03-16 05:58, 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/jit-elf.exp"
> 
> we can see the following messages in gdb/testsuite/gdb.log:
> 
>   (gdb) attach 1650108
>   Attaching to program: /home/yangtiezhu/build/gdb/testsuite/outputs/gdb.base/jit-elf/jit-elf-main, process 1650108
>   ptrace: Operation not permitted.
>   (gdb) FAIL: gdb.base/jit-elf.exp: attach: one_jit_test-2: break here 1: attach
> 
> handle the above case in gdb_attach, and then use gdb_attach to fix
> the above issue.
> 
> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
> ---
>  gdb/testsuite/gdb.base/jit-elf.exp | 9 ++-------
>  gdb/testsuite/lib/gdb.exp          | 8 ++++++++
>  2 files changed, 10 insertions(+), 7 deletions(-)
> 
> diff --git a/gdb/testsuite/gdb.base/jit-elf.exp b/gdb/testsuite/gdb.base/jit-elf.exp
> index 8a4c5b7..61a51a2 100644
> --- a/gdb/testsuite/gdb.base/jit-elf.exp
> +++ b/gdb/testsuite/gdb.base/jit-elf.exp
> @@ -40,7 +40,7 @@ set jit_solib_srcfile ${srcdir}/${subdir}/${jit_solib_basename}.c
>  # Detach, restart GDB, and re-attach to the program.
>  proc clean_reattach {} {
>      global decimal gdb_prompt
> -    global main_binfile main_srcfile
> +    global main_binfile
>  
>      # Get PID of test program.
>      set testpid -1
> @@ -57,12 +57,7 @@ proc clean_reattach {} {
>  
>      clean_restart ${main_binfile}
>  
> -    set test "attach"
> -    gdb_test_multiple "attach $testpid" "$test" {
> -	-re "Attaching to program.*.*main.*at .*$main_srcfile:.*$gdb_prompt $" {
> -	    pass "$test"
> -	}
> -    }
> +    gdb_attach $testpid


Ok, to expand on my previous message: in order to allow matching for
some specific output, like this test does (to avoid losing some test
coverage), I propose to let the caller pass an extra pattern that will
be used in the catch-all success clause:

gdb_attach can be:

proc gdb_attach { testpid {options {}} } {
    parse_options {
	{pattern ""}
    }

    gdb_test_multiple "attach $testpid" "attach" {
	-re -wrap "Attaching to.*ptrace: Operation not permitted\\." {
		unsupported "$gdb_test_name (Operation not permitted)"
		return 0
	}

	-re -wrap "$pattern" {
		pass $gdb_test_name
	 	return 1
	}
    }
}

And the caller can do:

gdb_attach $testpid {
    "pattern" "main.*at .*$::main_srcfile:.*"
}

A simpler caller that doesn't care about the output can still do just:

gdb_attach $testpid

Note that you probably want to make the test return if gdb_attach
returns 0 (as you did in the previous test), so that we don't continue
and generate some FAILs.

>  
>      gdb_test_no_output "set var wait_for_gdb = 0"
>  }
> diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
> index 599e8cc..5751bde 100644
> --- a/gdb/testsuite/lib/gdb.exp
> +++ b/gdb/testsuite/lib/gdb.exp
> @@ -5114,6 +5114,14 @@ proc gdb_attach { testpid } {
>  	  unsupported "$gdb_test_name (Operation not permitted)"
>  	  return 0
>  	}
> +	-re -wrap "Attaching to program.*.*main.*at .*:.*" {
> +	  pass $gdb_test_name
> +	  return 1
> +	}
> +	-re -wrap "Attaching to program: .*, process $testpid\r\n.*ptrace: Operation not permitted\\." {
> +	  unsupported "$gdb_test_name (Operation not permitted)"
> +	  return 0
> +	}
>      }
>  }

This way we don't need to add many specific patterns like this.

Simon