[LTP] [PATCH v2 2/2] Add shmat04 SysV IPC bug reproducer

[Cyril Hrubis]

Hi!
> +static void change_access(void *addr, int size, int prot)
> +{
> +	switch (prot) {
> +	case PROT_NONE:
> +		tst_res(TINFO, "Disable memory access. addr: %p - size: %d",
> +			addr, size);
> +		break;
> +	case PROT_WRITE:
> +		tst_res(TINFO, "Enable write memory access. addr: %p - size: %d",
> +			addr, size);
> +		break;
> +	default:
> +		tst_res(TINFO, "Change memory access. addr: %p - size: %d",
> +			addr, size);
> +		break;
> +	}
> +
> +	SAFE_MPROTECT(addr, size, prot);
> +}

Hmm, it's kind of ugly how we wrap the macro here like that...

What about we instead add debugging messages to all the SAFE_MACROS()?

Given that we added TDEBUG flag recently we can do soemthing as:

	tst_res_(TDEBUG, file, lineno, "mprotect(%p, %d, %s)",
	         addr, size, prot_to_str(prot));

To the SAFE_MPROTECT() and get the verbose output for free with verbose
flag passed to the test.

We can do that with all SAFE_MACROS() then we do not have to print most
of the messages in this test...

> +
> +static void run(void)
> +{
> +	struct shmid_ds shmid_ds;
> +	void *sh_mem;
> +
> +	segment_id = SAFE_SHMGET(
> +		key_id,
> +		segment_size,
> +		IPC_CREAT | IPC_EXCL | 0600);
> +
> +	sh_mem = SAFE_SHMAT(segment_id, NULL, 0);
> +
> +	tst_res(TINFO, "Attached at %p. key: %d - size: %lu",
> +		sh_mem, segment_id, segment_size);
> +
> +	SAFE_SHMCTL(segment_id, IPC_STAT, &shmid_ds);
> +
> +	tst_res(TINFO, "Number of attaches: %lu", shmid_ds.shm_nattch);
> +
> +	change_access(sh_mem + page_size, page_size, PROT_NONE);
> +	change_access(sh_mem, 2 * page_size, PROT_WRITE);
> +
> +	SAFE_SHMCTL(segment_id, IPC_STAT, &shmid_ds);
> +
> +	tst_res(TINFO, "Number of attaches: %lu", shmid_ds.shm_nattch);
> +	tst_res(TINFO, "Delete attached memory");
> +
> +	SAFE_SHMDT(sh_mem);
> +	SAFE_SHMCTL(segment_id, IPC_STAT, &shmid_ds);
> +
> +	tst_res(TINFO, "Number of attaches: %lu", shmid_ds.shm_nattch);
> +
> +	SAFE_SHMCTL(segment_id, IPC_RMID, NULL);
> +	segment_id = -1;
> +
> +	if (shmid_ds.shm_nattch)
> +		tst_res(TFAIL, "The system is affected by the SysV IPC bug");
> +	else
> +		tst_res(TPASS, "Test passed");

These messages are not really that useful, we can as well do:

TST_EXP_EQ_LU(shmid_ds.shm_nattach, 0);

That will provide better message than "PASS: Test passed"

> +}
> +
> +static void setup(void)
> +{
> +	key_id = GETIPCKEY();
> +	page_size = getpagesize();
> +
> +	tst_res(TINFO, "Key id: %d", key_id);
> +	tst_res(TINFO, "Page size: %d", page_size);
> +
> +	segment_size = 3 * page_size;
> +}
> +
> +static void cleanup(void)
> +{
> +	if (segment_id != -1)
> +		SAFE_SHMCTL(segment_id, IPC_RMID, NULL);
> +}
> +
> +static struct tst_test test = {
> +	.test_all = run,
> +	.setup = setup,
> +	.cleanup = cleanup,
> +};
> -- 
> 2.35.3
> 
> 
> -- 
> Mailing list info: https://lists.linux.it/listinfo/ltp

-- 
Cyril Hrubis
chrubis@suse.cz