Re: [PATCH] selftests: prctl: Add prctl test for PR_GET_NAME

[Shuah Khan <skhan@linuxfoundation.org>]

On 8/6/23 09:18, Osama Muhammad wrote:
> This patch covers the testing of PR_GET_NAME by
> reading it's value from proc/self/task/pid/comm
> and matching it by the value returned by  PR_GET_NAME.
> 

So the values should match? Can you elaborate that in the
change log.

> Signed-off-by: Osama Muhammad <osmtendev@gmail.com>
> ---
>   .../selftests/prctl/set-process-name.c        | 25 +++++++++++++++++++
>   1 file changed, 25 insertions(+)
> 
> diff --git a/tools/testing/selftests/prctl/set-process-name.c b/tools/testing/selftests/prctl/set-process-name.c
> index 3bc5e0e09..41f4b105d 100644
> --- a/tools/testing/selftests/prctl/set-process-name.c
> +++ b/tools/testing/selftests/prctl/set-process-name.c
> @@ -47,6 +47,28 @@ int check_null_pointer(char *check_name)
>   	return res;
>   }
>   
> +int check_name(void)
> +{
> +
> +	int pid;
> +
> +	pid = getpid();
> +	FILE *fptr;
> +	char path[50] = {};

Define this and use it. Don't hard-code the size.
MAX_PATH_LEN - look for other such defines.

> +	int j;
> +
> +	j = snprintf(path, 50, "/proc/self/task/%d/comm", pid);

Here - it makes it easier to maintain.

> +	fptr = fopen(path, "r");
> +	char name[TASK_COMM_LEN] = {};
> +	int res = prctl(PR_GET_NAME, name, NULL, NULL, NULL);
> +	char output[TASK_COMM_LEN] = {};

Code after declarations please. It is easier to read and follow.

> +
> +	fscanf(fptr, "%s", output);

Don't you want to check error return here?

> +
> +	return !strcmp(output, name);
> +
> +}
> +
>   TEST(rename_process) {
>   
>   	EXPECT_GE(set_name(CHANGE_NAME), 0);
> @@ -57,6 +79,9 @@ TEST(rename_process) {
>   
>   	EXPECT_GE(set_name(CHANGE_NAME), 0);
>   	EXPECT_LT(check_null_pointer(CHANGE_NAME), 0);
> +

No need to for this extra line

> +	EXPECT_TRUE(check_name());
> +
>   }
>   
>   TEST_HARNESS_MAIN

thanks,
-- Shuah