[LTP] [PATCH v1 4/4] syscalls/shmget06: Add test when the id of shm_next_id has existed

[xuyang2018.jy@fujitsu.com]

Hi Cyril
> Hi!
>> diff --git a/testcases/kernel/syscalls/ipc/shmget/shmget06.c b/testcases/kernel/syscalls/ipc/shmget/shmget06.c
>> new file mode 100644
>> index 000000000..3138d4482
>> --- /dev/null
>> +++ b/testcases/kernel/syscalls/ipc/shmget/shmget06.c
>> @@ -0,0 +1,77 @@
>> +// SPDX-License-Identifier: GPL-2.0-or-later
>> +/*
>> + * Copyright (c) 2021 FUJITSU LIMITED. All rights reserved.
>> + * Author: Yang Xu<xuyang2018.jy@fujitsu.com>
>> + */
>> +
>> +/*\
>> + * [Description]
>> + *
>> + * It is a basic test about shm_next_id.
>                            ^
> 			  for
>> + *
>> + * When the shared memory segment identifier that shm_next_id stored has
>> + * existed, call shmget with different key just use another unused value in range
>        ^                                      ^
>        'does exist' instead of 'has existed'  |
>        or even better 'is allready in use'    |
>                                              will
>> + * [0,INT_MAX]. kernel doesn't guarantee the desired id.
>                     ^
> 		   Capital letter at the start of the sentence.
>> + */\
Will do.
>> +
>> +#include<errno.h>
>> +#include<string.h>
>> +#include<sys/types.h>
>> +#include<sys/ipc.h>
>> +#include<sys/shm.h>
>> +#include "tst_test.h"
>> +#include "tst_safe_sysv_ipc.h"
>> +#include "libnewipc.h"
>> +
>> +#define NEXT_ID_PATH "/proc/sys/kernel/shm_next_id"
>> +
>> +static int shm_id[2], pid;
>> +static key_t shmkey[2];
>> +
>> +static void verify_shmget(void)
>> +{
>> +	SAFE_FILE_PRINTF(NEXT_ID_PATH, "%d", shm_id[0]);
>> +
>> +	shm_id[1] = SAFE_SHMGET(shmkey[1], SHM_SIZE, IPC_CREAT | SHM_RW);
>> +	if (shm_id[1] == shm_id[0])
>> +		tst_res(TFAIL, "shm id %d has existed, shmget() returns the"
>> +			" same shm id unexpectedly", shm_id[0]);
>> +	else
>> +		tst_res(TPASS, "shm id %d has existed, shmget() returns the"
>> +			" new shm id %d", shm_id[0], shm_id[1]);
>> +
>> +	SAFE_SHMCTL(shm_id[1], IPC_RMID, NULL);
>> +}
>> +
>> +static void setup(void)
>> +{
>> +	shmkey[0] = GETIPCKEY();
>> +	shmkey[1] = GETIPCKEY();
>> +	pid = getpid();
>> +	SAFE_FILE_PRINTF(NEXT_ID_PATH, "%d", pid);
>
> So we are using this to "randomize" the id here right?
Yes.
>
>> +	shm_id[0] = SAFE_SHMGET(shmkey[0], SHM_SIZE, IPC_CREAT | SHM_RW);
>> +	tst_res(TINFO, "Test shm_next_id effects on shmget(different key) "
>> +		"when this identifier of shared memory segment has existed");
>
> I do not think that printing test description is useful, especially
> since we have nicely formatted test description in the test source which
> gets exported into the metadata.
Will remove it on v2.
>
>> +}
>> +
>> +static void cleanup(void)
>> +{
>> +	int i;
>> +
>> +	for (i = 0; i<  2; i++) {
>> +		if (shm_id[i] != -1)
>> +			SAFE_SHMCTL(shm_id[i], IPC_RMID, NULL);
>> +	}
>> +}
>> +
>> +static struct tst_test test = {
>> +	.needs_tmpdir = 1,
>> +	.setup = setup,
>> +	.cleanup = cleanup,
>> +	.test_all = verify_shmget,
>> +	.needs_kconfigs = (const char *[]) {
>> +		"CONFIG_CHECKPOINT_RESTORE=y",
>> +		NULL
>> +	},
>> +	.needs_root = 1,
>> +};
>
> With the minor adjustements in description:
>
> Reivewed-by: Cyril Hrubis<chrubis@suse.cz>
>