[PATCH 2 wayland] tests: detect if debugger is attached

[Pekka Paalanen]

On Wed, 19 Nov 2014 12:20:31 +0100
Marek Chalupa <mchqwerty at gmail.com> wrote:

> Copy function from libinput/test/litest.c is_debugger_detached()
> and use it in our test-runner. If debugger is attached, turn off
> leak checks and timeouts automatically.
> 
> Revision of libinput: 028513a0a723e97941c39c4aeb17433198723913
> 
> Signed-off-by: Marek Chalupa <mchqwerty at gmail.com>
> ---
>  tests/test-runner.c | 43 +++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 41 insertions(+), 2 deletions(-)
> 
> diff --git a/tests/test-runner.c b/tests/test-runner.c
> index 1373225..63b25ed 100644
> --- a/tests/test-runner.c
> +++ b/tests/test-runner.c
> @@ -33,6 +33,7 @@
>  #include <dlfcn.h>
>  #include <errno.h>
>  #include <limits.h>
> +#include <sys/ptrace.h>
>  
>  #include "test-runner.h"
>  
> @@ -224,6 +225,39 @@ rmdir_xdg_runtime_dir(void)
>  		perror("Cleaning XDG_RUNTIME_DIR");
>  }
>  
> +
> +/* this function is taken from libinput/test/litest.c
> + * (rev 028513a0a723e97941c39)
> + */
> +static int
> +is_debugger_attached(void)
> +{
> +	int status;
> +	int rc;
> +	int pid = fork();
> +
> +	if (pid == -1)
> +		return 0;
> +
> +	if (pid == 0) {
> +		int ppid = getppid();
> +		if (ptrace(PTRACE_ATTACH, ppid, NULL, NULL) == 0) {
> +			waitpid(ppid, NULL, 0);
> +			ptrace(PTRACE_CONT, NULL, NULL);
> +			ptrace(PTRACE_DETACH, ppid, NULL, NULL);
> +			rc = 0;
> +		} else {
> +			rc = 1;
> +		}
> +		_exit(rc);
> +	} else {
> +		waitpid(pid, &status, 0);
> +		rc = WEXITSTATUS(status);
> +	}
> +
> +	return rc;
> +}
> +
>  int main(int argc, char *argv[])
>  {
>  	const struct test *t;
> @@ -237,8 +271,13 @@ int main(int argc, char *argv[])
>  	sys_malloc = dlsym(RTLD_NEXT, "malloc");
>  	sys_free = dlsym(RTLD_NEXT, "free");
>  
> -	leak_check_enabled = !getenv("WAYLAND_TESTS_NO_LEAK_CHECK");
> -	timeouts_enabled = !getenv("WAYLAND_TESTS_NO_TIMEOUTS");
> +	if (is_debugger_attached()) {
> +		leak_check_enabled = 0;
> +		timeouts_enabled = 0;
> +	} else {
> +		leak_check_enabled = !getenv("WAYLAND_TESTS_NO_LEAK_CHECK");
> +		timeouts_enabled = !getenv("WAYLAND_TESTS_NO_TIMEOUTS");
> +	}
>  
>  	if (argc == 2 && strcmp(argv[1], "--help") == 0)
>  		usage(argv[0], EXIT_SUCCESS);

Hi,

I'm a little wary of this kind of magic. You can't force-enable these
settings under a debugger now, but I'm not sure anyone would want to.

Would need a trivial rebase.

Libinput seems use the debugger detection for preventing test forking,
and we have our own way for that by running a single sub-test.

Do we care enough to have this patch?


Thanks,
pq