Re: [PATCH v2] selftest: acct: Add selftest for the acct() syscall

[Shuah Khan <skhan@linuxfoundation.org>]

On 6/30/24 13:22, Abdulrasaq Lawani wrote:
> Noticed that there was no selftest for the acct() syscall
> which enables the kernel to record terminated processes
> into a specified file.
> 
> The acct() system call enables or disables process accounting.
> If accounting is turned on, records for each terminating process
> are appended to a specified filename as it terminates. An argument of NULL
> causes accounting to be turned off.
> 
> This patch provides a test for the acct() syscall.
> 
> References:
> https://man7.org/linux/man-pages/man2/acct.2.html
> 
> Signed-off-by: Abdulrasaq Lawani <abdulrasaqolawani@gmail.com>

What does the test output look like?

> ---
> Changes in v2:
> Add testcases to test error conditions.
> Add kselftest function for reporting results.
> 
> - Link to v1: https://lore.kernel.org/r/20240622-kselftest-acct-syscall-v1-1-d270b5be8d37@gmail.com
> ---
>   tools/testing/selftests/Makefile            |  1 +
>   tools/testing/selftests/acct/.gitignore     |  2 +
>   tools/testing/selftests/acct/Makefile       |  4 ++
>   tools/testing/selftests/acct/acct_syscall.c | 89 +++++++++++++++++++++++++++++
>   4 files changed, 96 insertions(+)
> 
> diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
> index 9039f3709aff..45a58ef5ad92 100644
> --- a/tools/testing/selftests/Makefile
> +++ b/tools/testing/selftests/Makefile
> @@ -1,4 +1,5 @@
>   # SPDX-License-Identifier: GPL-2.0
> +TARGETS += acct
>   TARGETS += alsa
>   TARGETS += amd-pstate
>   TARGETS += arm64
> diff --git a/tools/testing/selftests/acct/.gitignore b/tools/testing/selftests/acct/.gitignore
> new file mode 100644
> index 000000000000..8ab358d81bd2
> --- /dev/null
> +++ b/tools/testing/selftests/acct/.gitignore
> @@ -0,0 +1,2 @@
> +acct_syscall
> +config
> \ No newline at end of file

What is this?

> diff --git a/tools/testing/selftests/acct/Makefile b/tools/testing/selftests/acct/Makefile
> new file mode 100644
> index 000000000000..ff3e238c5634
> --- /dev/null
> +++ b/tools/testing/selftests/acct/Makefile
> @@ -0,0 +1,4 @@
> +TEST_GEN_PROGS := acct_syscall
> +CFLAGS += -Wall
> +
> +include ../lib.mk
> \ No newline at end of file
> diff --git a/tools/testing/selftests/acct/acct_syscall.c b/tools/testing/selftests/acct/acct_syscall.c
> new file mode 100644
> index 000000000000..4fa00a88a1bd
> --- /dev/null
> +++ b/tools/testing/selftests/acct/acct_syscall.c
> @@ -0,0 +1,89 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +/* kselftest for acct() system call
> + *  The acct() system call enables or disables process accounting.
> + */
> +
> +#include <stdio.h>
> +#include <errno.h>
> +#include <string.h>
> +#include <sys/wait.h>
> +
> +#include "../kselftest.h"
> +
> +int main(void)
> +{
> +	// Setting up kselftest framework
> +	ksft_print_header();
> +	ksft_set_plan(1);
> +
> +	// Create file to log closed processes
> +	char filename[] = "process_log";

Where does this file created?

> +	FILE *fp;
> +
> +	fp = fopen(filename, "w");

What happens if file creation fails?

> +
> +	int i = acct(filename);

Chose a descriptive name for the variable e.g: ret

> +
> +	// Handle error conditions
> +	if (i) {

Is this the failure case - ret < 0 case - complete conditional.

> +		switch (errno) {
> +		case EPERM:
> +			ksft_test_result_error("%s. Please run the test as root.\n",
> +				strerror(errno));
> +			break;
> +
> +		case EACCES:
> +			ksft_test_result_error("Insufficient privilege.\n");
> +			break;
> +
> +		case EIO:
> +			ksft_test_result_error("Error writing to the file: %s.\n", filename);
> +			break;
> +
> +		default:
> +			ksft_test_result_error("%s.\n", strerror(errno));
> +			break;
> +		}
> +
> +		remove(filename);
> +		fclose(fp);
> +		ksft_finished();
> +		return 1;
> +	}
> +
> +	// Create child process and wait for it to terminate.
> +	pid_t child_pid;
> +
> +	child_pid = fork();
> +
> +	if (child_pid < 0) {
> +		ksft_test_result_error("Process failed\n");
> +		ksft_finished();
> +		return 1;
> +	} else if (child_pid == 0) {
> +		ksft_print_msg("Child process successfully created!\n");

You don't need braces here since it it a single statement after the
conditional.

> +	} else {
> +		wait(NULL);
> +		fseek(fp, 0L, SEEK_END);
> +		int sz = ftell(fp);
> +
> +		ksft_print_msg("Parent process successfully created!\n");
> +
> +		i = acct(NULL);
> +
> +		if (sz <= 0) {
> +			ksft_test_result_fail("Terminated child process not logged");
> +			ksft_exit_fail();
> +			return 1;
> +		}
> +
> +		ksft_test_result_pass("Successfully logged terminated process.\n");
> +		remove(filename);
> +		fclose(fp);
> +		ksft_exit_pass();
> +		return 0;
> +	}
> +
> +	return 1;
> +}
> 
> ---
> base-commit: 50736169ecc8387247fe6a00932852ce7b057083
> change-id: 20240622-kselftest-acct-syscall-2d90f7666b1e
> 
> Best regards,

Please check coding guidelines and ruun checkpatch on this.