[LTP] [PATCH] mem: Convert shmt02 to new API

[Andrea Cervesato]

Hi!

On 6/18/25 13:46, Ricardo B. Marlière via ltp wrote:
> From: Ricardo B. Marlière <rbm@suse.com>
>
> Signed-off-by: Ricardo B. Marlière <rbm@suse.com>
> ---
>   testcases/kernel/mem/shmt/shmt02.c | 118 +++++++------------------------------
>   1 file changed, 21 insertions(+), 97 deletions(-)
>
> diff --git a/testcases/kernel/mem/shmt/shmt02.c b/testcases/kernel/mem/shmt/shmt02.c
> index b33a042f93625cf44af1c3de6354248919f21522..f1dfec5028afb116f5393ff4b4869a7ea3099071 100644
> --- a/testcases/kernel/mem/shmt/shmt02.c
> +++ b/testcases/kernel/mem/shmt/shmt02.c
> @@ -1,120 +1,44 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
>   /*
> - *
> - *   Copyright (c) International Business Machines  Corp., 2002
> - *
> - *   This program is free software;  you can redistribute it and/or modify
> - *   it under the terms of the GNU General Public License as published by
> - *   the Free Software Foundation; either version 2 of the License, or
> - *   (at your option) any later version.
> - *
> - *   This program is distributed in the hope that it will be useful,
> - *   but WITHOUT ANY WARRANTY;  without even the implied warranty of
> - *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
> - *   the GNU General Public License for more details.
> - *
> - *   You should have received a copy of the GNU General Public License
> - *   along with this program;  if not, write to the Free Software
> - *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
> + * Copyright (c) International Business Machines  Corp., 2002
> + *	12/20/2002	Port to LTP	robbiew@us.ibm.com
> + *	06/30/2001	Port to Linux	nsharoff@us.ibm.com
> + * Copyright (c) 2025 SUSE LLC Ricardo B. Marlière <rbm@suse.com>
>    */
>   
> -/* 12/20/2002		 Port to LTP		 robbiew@us.ibm.com */
> -/* 06/30/2001		 Port to Linux		 nsharoff@us.ibm.com */
> -
> -/*
> - * NAME
> - *		 shmt02
> - *
> - * CALLS
> - *		 shmctl(2) shmget(2)
> - *
> - * ALGORITHM
> +/*\
>    * Create and attach a shared memory segment, write to it
> - * and then remove it.		  Verify that the shared memory segment
> + * and then remove it. Verify that the shared memory segment
>    * is accessible as long as the process is still alive.
> - *
>    */
>   
> -#include <stdio.h>
> -#include <sys/types.h>
> -#include <sys/ipc.h>
> -#include <sys/shm.h>
> -#include <sys/utsname.h>
> -#include <errno.h>
> -
> -/** LTP Port **/
> -#include "test.h"
> -
> -char *TCID = "shmt02";		/* Test program identifier.    */
> -int TST_TOTAL = 3;		/* Total number of test cases. */
> -
> -/**************/
> +#include "tst_safe_sysv_ipc.h"
tst_test.h usually go first, because other headers often needs it.
> +#include "tst_test.h"
>   
> -#define K_1 1024
> -
> -static int rm_shm(int);
> -
> -int main(void)
> +static void run(void)
>   {
>   	register int shmid;
>   	char *cp;
>   	key_t key;
>   
>   	errno = 0;
> -	key = (key_t) getpid();
> -
> -/*----------------------------------------------------------------*/
> -
> -	if ((shmid = shmget(key, 16 * K_1, IPC_CREAT | 0666)) < 0) {
> -		perror("shmget");
> -		tst_brkm(TFAIL, NULL,
> -			 "shmget Failed: shmid = %d, errno = %d",
> -			 shmid, errno);
> -	}
> +	key = (key_t)getpid();
>   
> -	tst_resm(TPASS, "shmget");
> -
> -/*----------------------------------------------------------------*/
> -
> -	cp = shmat(shmid, NULL, 0);
> -
> -	if (cp == (char *)-1) {
> -		perror("shmat");
> -		tst_resm(TFAIL, "shmat Failed: shmid = %d, errno = %d",
> -			 shmid, errno);
> -		rm_shm(shmid);
> -		tst_exit();
> -	}
> +	shmid = SAFE_SHMGET(key, 16 * 1024, IPC_CREAT | 0666);

#define SHMSIZE (16 * TST_KB)

SAFE_SHMGET(key, SHMSIZE, IPC_CREAT | 0666);

But I guess we can use a small buffer (read below). Everything will be 
rounded to the next PAGE_SIZE anyway.

>   
> +	cp = SAFE_SHMAT(shmid, NULL, 0);
>   	*cp = '1';
>   	*(cp + 1) = '2';

I'm wondering if it makes sense to use 2 bytes. Either we use one byte 
or we write a random string and read it back. In the second case, we can 
copy the first bytes of tst_rand_data bytes and compare them later on, 
once  IPC_RMID is called.

>   
> -	tst_resm(TPASS, "shmat");
> -
> -/*----------------------------------------------------------------*/
> -
> -	rm_shm(shmid);
> +	SAFE_SHMCTL(shmid, IPC_RMID, NULL);
>   
> -	if (*cp != '1' || *(cp + 1) != '2') {
> -		tst_resm(TFAIL,
> -			 "Error in shared memory contents: shmid = %d",
> -			 shmid);
> -	}
> +	if (*cp != '1' || *(cp + 1) != '2')
> +		tst_res(TFAIL, "Error in shared memory contents: shmid = %d",
> +			shmid);
Here we can just use TST_EXP_EQ_STRN if we copy random data or a simple 
if statement for single byte.
>   
> -	tst_resm(TPASS, "Correct shared memory contents");
> -
> -/*------------------------------------------------------------------*/
> -
> -	tst_exit();
> +	tst_res(TPASS, "Correct shared memory contents");
This one should be inside the "else" statement.
>   }
>   
> -static int rm_shm(int shmid)
> -{
> -	if (shmctl(shmid, IPC_RMID, NULL) == -1) {
> -		perror("shmctl");
> -		tst_brkm(TFAIL,
> -			 NULL,
> -			 "shmctl Failed to remove: shmid = %d, errno = %d",
> -			 shmid, errno);
> -	}
> -	return (0);
> -}
> +static struct tst_test test = {
> +	.test_all = run,
> +};
>
> ---
> base-commit: df591113afeb31107bc45bd5ba28a99b556d1028
> change-id: 20250618-conversions-shmt-5ea5a5ebe55e
>
> Best regards,

We are only testing that the memory is accessible from the current 
process, but we are not testing if the memory is no longer accessible 
after the process which has created memory is still alive. This would 
require to spawn a new process, allocate memory, check memory is 
available after IPC_RMID, but not available after process exited.

- Andrea