[LTP] [PATCH] unlink: Add error tests for EPERM and EROFS

[Yang Xu (Fujitsu)]

Hi Avinesh.

Thanks for your comments.

> Hi Yang Xu,
> some comments below
> 
> On Monday, April 1, 2024 4:49:48 AM CEST Yang Xu via ltp wrote:
>> Add negative cases for unlink(), when errno is EPERM or EROFS.
>>
>> Signed-off-by: Yang Xu <xuyang2018.jy@fujitsu.com>
>> ---
>>   runtest/syscalls                            |  1 +
>>   testcases/kernel/syscalls/unlink/.gitignore |  1 +
>>   testcases/kernel/syscalls/unlink/unlink09.c | 86 +++++++++++++++++++++
>>   3 files changed, 88 insertions(+)
>>   create mode 100644 testcases/kernel/syscalls/unlink/unlink09.c
>>
>> diff --git a/runtest/syscalls b/runtest/syscalls
>> index 4ed2b5602..b99ce7170 100644
>> --- a/runtest/syscalls
>> +++ b/runtest/syscalls
>> @@ -1651,6 +1651,7 @@ unlink01 symlink01 -T unlink01
>>   unlink05 unlink05
>>   unlink07 unlink07
>>   unlink08 unlink08
>> +unlink09 unlink09
>>
>>   #unlinkat test cases
>>   unlinkat01 unlinkat01
>> diff --git a/testcases/kernel/syscalls/unlink/.gitignore
>> b/testcases/kernel/syscalls/unlink/.gitignore index 2e783580d..6038cc29d
>> 100644
>> --- a/testcases/kernel/syscalls/unlink/.gitignore
>> +++ b/testcases/kernel/syscalls/unlink/.gitignore
>> @@ -1,3 +1,4 @@
>>   /unlink05
>>   /unlink07
>>   /unlink08
>> +/unlink09
>> diff --git a/testcases/kernel/syscalls/unlink/unlink09.c
>> b/testcases/kernel/syscalls/unlink/unlink09.c new file mode 100644
>> index 000000000..b7ff94ee6
>> --- /dev/null
>> +++ b/testcases/kernel/syscalls/unlink/unlink09.c
>> @@ -0,0 +1,86 @@
>> +// SPDX-License-Identifier: GPL-2.0-or-later
>> +/*
>> + * Copyright (c) 2024 FUJITSU LIMITED. All Rights Reserved.
>> + * Author: Yang Xu <xuyang2018.jy@fujitsu.com>
>> + */
>> +
>> +/*\
>> + * [Description]
>> + *
>> + * Verify that unlink(2) fails with
>> + *
>> + * - EPERM when target file is marked as immutable or append-only
>> + * - EROFS when target file is on a read-only filesystem.
>> + */
>> +
>> +#include <errno.h>
>> +#include <unistd.h>
>> +#include <sys/ioctl.h>
>> +#include "tst_test.h"
>> +#include "tst_safe_macros.h"
>> +#include "lapi/fs.h"
> errno.h, unistd.h, ioctl.h and tst_safe_macros.h headers are already included
> via tst_test.h
>   
>> +
>> +#define TEST_EPERM_IMMUTABLE "test_eperm_immutable"
>> +#define TEST_EPERM_APPEND_ONLY "test_eperm_append_only"
>> +#define DIR_EROFS "erofs"
>> +#define TEST_EROFS "erofs/test_erofs"
>> +
>> +static int fd_immutable;
>> +static int fd_append_only;
>> +
>> +static struct test_case_t {
>> +	char *filename;
>> +	int expected_errno;
>> +	char *desc;
>> +} tcases[] = {
>> +	{TEST_EPERM_IMMUTABLE, EPERM, "target file is immutable"},
>> +	{TEST_EPERM_APPEND_ONLY, EPERM, "target file is append-only"},
>> +	{TEST_EROFS, EROFS, "target file in read-only filesystem"},
>> +};
>> +
>> +static void setup(void)
>> +{
>> +	int attr;
>> +
>> +	fd_immutable = SAFE_OPEN(TEST_EPERM_IMMUTABLE, O_CREAT, 0600);
>> +	ioctl(fd_immutable, FS_IOC_GETFLAGS, &attr);
>> +	attr |= FS_IMMUTABLE_FL;
>> +	ioctl(fd_immutable, FS_IOC_SETFLAGS, &attr);
>> +
>> +	fd_append_only = SAFE_OPEN(TEST_EPERM_APPEND_ONLY, O_CREAT, 0600);
>> +	ioctl(fd_append_only, FS_IOC_GETFLAGS, &attr);
>> +	attr |= FS_APPEND_FL;
>> +	ioctl(fd_append_only, FS_IOC_SETFLAGS, &attr);
> We can use SAFE_IOCTL() in all places.
>> +}
>> +
>> +static void cleanup(void)
>> +{
>> +	int attr;
>> +
>> +	ioctl(fd_immutable, FS_IOC_GETFLAGS, &attr);
>> +	attr &= ~FS_IMMUTABLE_FL;
>> +	ioctl(fd_immutable, FS_IOC_SETFLAGS, &attr);
>> +	SAFE_CLOSE(fd_immutable);
>> +
>> +	ioctl(fd_append_only, FS_IOC_GETFLAGS, &attr);
>> +	attr &= ~FS_APPEND_FL;
>> +	ioctl(fd_append_only, FS_IOC_SETFLAGS, &attr);
>> +	SAFE_CLOSE(fd_append_only);
>> +}
>> +
>> +static void verify_unlink(unsigned int i)
>> +{
>> +	struct test_case_t *tc = &tcases[i];
>> +
>> +	TST_EXP_FAIL(unlink(tc->filename), tc->expected_errno, "%s", tc->desc);
> If for whatever reason, unlink() call passes here, further test iterations
> will not work correctly as test file no longer exist. I guess we need to handle
> the restoring in this main test function. And cleanup() does not need to reset
> any flags as it is called only once after all the iterations.
> 
In this case, every iteration uses a separate file. Even if unlink() 
passes unexpectedly, other iteration will not be affected.
So I think there is no need to restore the file.

The reset of flag is for the test file cleanup.

If flag is not reset, the test framework will throw a warning as following:
tst_tmpdir.c:343: TWARN: tst_rmdir: rmobj(/tmp/LTP_unlYn0Rtu) failed: 
unlink(/tmp/LTP_unlYn0Rtu/test_eperm_append_only) failed; errno=1: EPERM

In tst_tmpdir.c, unlink is called to remove the temp file and dir. So if 
flag is not reset, the temp file and dir will not be removed.

Soon I will send out V2 patch.

Best regards
Yang Xu

>> +}
>> +
>> +static struct tst_test test = {
>> +	.setup = setup,
>> +	.tcnt = ARRAY_SIZE(tcases),
>> +	.cleanup = cleanup,
>> +	.test = verify_unlink,
>> +	.needs_rofs = 1,
>> +	.mntpoint = DIR_EROFS,
>> +	.needs_root = 1,
>> +};
> 
> 
> Regards,
> Avinesh
> 
> 
>