Re: [LTP] [PATCH 1/3] syscalls: munmap01: Convert to new API

["Ricardo B. Marlière via ltp" <ltp@lists.linux.it>]

On Fri Jul 4, 2025 at 9:03 AM -03, Andrea Cervesato wrote:
> Hi!
>
> The conversion of the old API test is still bringing things which we 
> want to get rid in the new test.
> Read below.
>
> On 7/3/25 8:39 PM, Ricardo B. Marlière via ltp wrote:
>> From: Ricardo B. Marlière <rbm@suse.com>
>>
>> Signed-off-by: Ricardo B. Marlière <rbm@suse.com>
>> ---
>>   testcases/kernel/syscalls/munmap/munmap01.c | 244 ++++++----------------------
>>   1 file changed, 52 insertions(+), 192 deletions(-)
>>
>> diff --git a/testcases/kernel/syscalls/munmap/munmap01.c b/testcases/kernel/syscalls/munmap/munmap01.c
>> index dfd81fa2b32de2354a8053c4b7ebf1d518b8bb67..b602c3094d7b351a69afe84b0c9c03d72078e64d 100644
>> --- a/testcases/kernel/syscalls/munmap/munmap01.c
>> +++ b/testcases/kernel/syscalls/munmap/munmap01.c
>> @@ -1,157 +1,55 @@
>> +// SPDX-License-Identifier: GPL-2.0-or-later
>>   /*
>> - *
>> - *   Copyright (c) International Business Machines  Corp., 2001
>> - *
>> - *   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., 2001
>> + *	07/2001 Ported by Wayne Boyer
>> + * Copyright (c) 2025 SUSE LLC Ricardo B. Marlière <rbm@suse.com>
>>    */
>>   
>> -/*
>> - * Test Name: munmap01
>> +/*\
>> + * Verify that, munmap call will succeed to unmap a mapped file or
>> + * anonymous shared memory region from the calling process's address space
>> + * and after successful completion of munmap, the unmapped region is no
>> + * longer accessible.
>>    *
>> - * Test Description:
>> - *  Verify that, munmap call will succeed to unmap a mapped file or
>> - *  anonymous shared memory region from the calling process's address space
>> - *  and after successful completion of munmap, the unmapped region is no
>> - *  longer accessible.
>> - *
>> - * Expected Result:
>> - *  munmap call should succeed to unmap a mapped file or anonymous shared
>> - *  memory region from the process's address space and it returns with a
>> - *  value 0, further reference to the unmapped region should result in a
>> - *  segmentation fault (SIGSEGV).
>> - *
>> - * Algorithm:
>> - *  Setup:
>> - *   Setup signal handling.
>> - *   Create temporary directory.
>> - *   Pause for SIGUSR1 if option specified.
>> - *
>> - *  Test:
>> - *   Loop if the proper options are given.
>> - *   Execute system call
>> - *   Check return code, if system call failed (return=-1)
>> - *   	Log the errno and Issue a FAIL message.
>> - *   Otherwise,
>> - *   	Verify the Functionality of system call
>> - *      if successful,
>> - *      	Issue Functionality-Pass message.
>> - *      Otherwise,
>> - *		Issue Functionality-Fail message.
>> - *  Cleanup:
>> - *   Print errno log and/or timing stats if options given
>> - *   Delete the temporary directory created.
>> - *
>> - * Usage:  <for command-line>
>> - *  munmap01 [-c n] [-f] [-i n] [-I x] [-P x] [-t]
>> - *     where,  -c n : Run n copies concurrently.
>> - *             -f   : Turn off functionality Testing.
>> - *	       -i n : Execute test n times.
>> - *	       -I x : Execute test for x seconds.
>> - *	       -P x : Pause for x seconds between iterations.
>> - *	       -t   : Turn on syscall timing.
>> - *
>> - * HISTORY
>> - *	07/2001 Ported by Wayne Boyer
>> - *
>> - * RESTRICTIONS:
>> - *  None.$
>> + * munmap call should succeed to unmap a mapped file or anonymous shared
>> + * memory region from the process's address space and it returns with a
>> + * value 0, further reference to the unmapped region should result in a
>> + * segmentation fault (SIGSEGV).
>>    */
>> -#include <errno.h>
>> -#include <unistd.h>
>> -#include <fcntl.h>
>> -#include <sys/stat.h>
>> -#include <sys/mman.h>
>> -
>> -#include "test.h"
>> -#include "safe_macros.h"
>> -
>> -#define TEMPFILE	"mmapfile"
>>   
>> -char *TCID = "munmap01";
>> -int TST_TOTAL = 1;
>> +#include "tst_test.h"
>>   
>> -char *addr;			/* addr of memory mapped region */
>> -int fildes;			/* file descriptor for tempfile */
>> -unsigned int map_len;		/* length of the region to be mapped */
>> +static int fd;
>> +static char *map_addr;
>> +static unsigned int map_len;
>>   
>> -void setup();			/* Main setup function of test */
>> -void cleanup();			/* cleanup function for the test */
>> -void sig_handler();		/* signal catching function */
>> -
>> -int main(int ac, char **av)
>> +static void run(void)
>>   {
>> -	int lc;
>> -
>> -	tst_parse_opts(ac, av, NULL, NULL);
>> -
>> -	for (lc = 0; TEST_LOOPING(lc); lc++) {
>> -
>> -		tst_count = 0;
>> -
>> -		setup();
>> -
>> -		/*
>> -		 * Call munmap to unmap the mapped region of the
>> -		 * temporary file from the calling process's address space.
>> -		 */
>> -		TEST(munmap(addr, map_len));
>> -
>> -		/* Check for the return value of munmap() */
>> -		if (TEST_RETURN == -1) {
>> -			tst_resm(TFAIL, "munmap() fails, errno=%d : %s",
>> -				 TEST_ERRNO, strerror(TEST_ERRNO));
>> -			continue;
>> -		}
>> -
>> -		/*
>> -		 * Check whether further reference is possible
>> -		 * to the unmapped memory region by writing
>> -		 * to the first byte of region with
>> -		 * some arbitrary number.
>> -		 */
>> -		*addr = 50;
>> +	SAFE_MUNMAP(map_addr, map_len);
>>   
>> -		/* This message is printed if no SIGSEGV */
>> -		tst_resm(TFAIL, "process succeeds to refer unmapped memory region");
>> +	/*
>> +	 * Check whether further reference is possible to the unmapped memory
>> +	 * region by writing to the first byte of region with some arbitrary
>> +	 * number.
>> +	 */
>> +	*map_addr = 50;
>>   
>> -		cleanup();
>> +	/* This message is printed if no SIGSEGV */
>> +	tst_res(TFAIL, "process succeeds to refer unmapped memory region");
>> +}
>>   
>> -	}
>> -	tst_exit();
>> +static void sig_handler(LTP_ATTRIBUTE_UNUSED int i)
>> +{
>> +	tst_res(TPASS, "Functionality of munmap() successful");
>> +	_exit(0);
>>   }
> Signals must be used carefully and in specific situations due to their 
> asynchronous nature. In this case, we can just SAFE_FORK() a child and 
> to verify that child has been signaled after accessing a un-mapped memory.

Ah, indeed.. Sorry about that, I keep forgetting some things even if I
did them before.

>>   
>> -/*
>> - * setup() - performs all ONE TIME setup for this test.
>> - *
>> - * Set up signal handler to catch SIGSEGV.
>> - * Get system page size, create a temporary file for reading/writing,
>> - * write one byte data into it, map the open file for the specified
>> - * map length.
>> - */
>> -void setup(void)
>> +static void setup(void)
>>   {
>>   	size_t page_sz;
>>   
>> -	tst_sig(NOFORK, DEF_HANDLER, cleanup);
>> -
>> -	/* call signal function to trap the signal generated */
>> -	if (signal(SIGSEGV, sig_handler) == SIG_ERR) {
>> -		tst_brkm(TBROK, cleanup, "signal fails to catch signal");
>> -	}
>> -
>> -	TEST_PAUSE;
>> +	/* Call signal function to trap the signal generated */
>> +	SAFE_SIGNAL(SIGSEGV, sig_handler);
>>   
>>   	/* Get the system page size */
>>   	page_sz = getpagesize();
>> @@ -162,74 +60,36 @@ void setup(void)
>>   	 */
>>   	map_len = 3 * page_sz;
>>   
>> -	tst_tmpdir();
>> -
>> -	/* Creat a temporary file used for mapping */
>> -	if ((fildes = open(TEMPFILE, O_RDWR | O_CREAT, 0666)) < 0) {
>> -		tst_brkm(TBROK, cleanup, "open() on %s Failed, errno=%d : %s",
>> -			 TEMPFILE, errno, strerror(errno));
>> -	}
>> +	/* Create a temporary file used for mapping */
>> +	fd = SAFE_OPEN("mmapfile", O_RDWR | O_CREAT, 0666);
>>   
>>   	/*
>> -	 * move the file pointer to maplength position from the beginning
>> +	 * Move the file pointer to maplength position from the beginning
>>   	 * of the file.
>>   	 */
>> -	SAFE_LSEEK(cleanup, fildes, map_len, SEEK_SET);
>> +	SAFE_LSEEK(fd, map_len, SEEK_SET);
>>   
>>   	/* Write one byte into temporary file */
>> -	if (write(fildes, "a", 1) != 1) {
>> -		tst_brkm(TBROK, cleanup, "write() on %s Failed, errno=%d : %s",
>> -			 TEMPFILE, errno, strerror(errno));
>> -	}
>> +	SAFE_WRITE(SAFE_WRITE_ALL, fd, "a", 1);
>>   
>>   	/*
>> -	 * map the open file 'TEMPFILE' from its beginning up to the maplength
>> +	 * Map the open file 'mmapfile' from its beginning up to the maplength
>>   	 * into the calling process's address space at the system choosen
>>   	 * with read/write permissions to the mapped region.
>>   	 */
>> -	addr = mmap(0, map_len, PROT_READ | PROT_WRITE,
>> -		    MAP_FILE | MAP_SHARED, fildes, 0);
>> -
>> -	/* check for the return value of mmap system call */
>> -	if (addr == (char *)MAP_FAILED) {
>> -		tst_brkm(TBROK, cleanup, "mmap() Failed on %s, errno=%d : %s",
>> -			 TEMPFILE, errno, strerror(errno));
>> -	}
>> -
>> +	map_addr = SAFE_MMAP(0, map_len, PROT_READ | PROT_WRITE,
>> +			     MAP_FILE | MAP_SHARED, fd, 0);
>>   }
>>   
>> -/*
>> - * sig_handler() - signal catching function.
>> - *   This function is used to trap the signal generated when tried to read or
>> - *   write to the memory mapped region which is already detached from the
>> - *   calling process address space.
>> - *   this function is invoked when SIGSEGV generated and it calls test
>> - *   cleanup function and exit the program.
>> - */
>> -void sig_handler(void)
>> +static void cleanup(void)
>>   {
>> -	tst_resm(TPASS, "Functionality of munmap() successful");
>> -
>> -	/* Invoke test cleanup function and exit */
>> -	cleanup();
>> -
>> -	tst_exit();
>> +	if (fd)
>> +		SAFE_CLOSE(fd);
>>   }
>>   
>> -/*
>> - * cleanup() - performs all ONE TIME cleanup for this test at
>> - *             completion or premature exit.
>> - *  	       Close the temporary file.
>> - *  	       Remove the temporary directory.
>> - */
>> -void cleanup(void)
>> -{
>> -
>> -	/* Close the temporary file */
>> -	if (close(fildes) < 0) {
>> -		tst_brkm(TFAIL, NULL, "close() on %s Failed, errno=%d : %s",
>> -			 TEMPFILE, errno, strerror(errno));
>> -	}
>> -
>> -	tst_rmdir();
>> -}
>> +static struct tst_test test = {
>> +	.test_all = run,
>> +	.setup = setup,
>> +	.cleanup = cleanup,
>> +	.needs_tmpdir = 1,
>> +};
>
> Also, please remove comments if not strictly needed, because they are 
> kind of obvious when we read the test code.

Sure!

Thanks for reviewing,
-	Ricardo.


>
> - Andrea


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