[CRIU] [PATCH 1/2] zdtm: Make file_locks04 test based on /proc/{pid}/fdinfo/{fd}

[Kirill Tkhai]

On 28.06.2016 21:02, Andrew Vagin wrote:
> On Tue, Jun 28, 2016 at 08:49:04PM +0300, Kirill Tkhai wrote:
>> /proc/locks is racy with adding/removing locks,
>> so we may lose test lock on a check.
>>
>> Use fdinfo list of locks instead.
> 
> fdinfo contains locks starting with the 4.1 kernel, how this test will
> work on older kernels?
> 
> What is about other file_locks* tests?

See the second patch
 
>>
>> Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
>> ---
>>  test/zdtm/static/file_locks04.c |   32 ++++++++++++++++++--------------
>>  1 file changed, 18 insertions(+), 14 deletions(-)
>>
>> diff --git a/test/zdtm/static/file_locks04.c b/test/zdtm/static/file_locks04.c
>> index 995dd09..dfb7c53 100644
>> --- a/test/zdtm/static/file_locks04.c
>> +++ b/test/zdtm/static/file_locks04.c
>> @@ -6,6 +6,7 @@
>>  #include <unistd.h>
>>  #include <sys/file.h>
>>  #include <string.h>
>> +#include <limits.h>
>>  #include <sys/wait.h>
>>  
>>  #include "zdtmtst.h"
>> @@ -16,27 +17,27 @@ const char *test_author	= "Pavel Emelyanov <xemul at parallels.com>";
>>  char *filename;
>>  TEST_OPTION(filename, string, "file name", 1);
>>  
>> -static int check_file_locks(int alt_pid, int fd)
>> +static int check_file_locks(pid_t child_pid, int fd, int child_fd)
>>  {
>> +	char		path[PATH_MAX];
>>  	FILE		*fp_locks = NULL;
>>  	char		buf[100], fl_flag[16], fl_type[16], fl_option[16];
>> -	pid_t		pid = getpid();
>>  	int		found = 0, num, fl_owner;
>>  
>> -	fp_locks = fopen("/proc/locks", "r");
>> -	if (!fp_locks)
>> +	sprintf(path, "/proc/%d/fdinfo/%d", child_pid, child_fd);
>> +	fp_locks = fopen(path, "r");
>> +	if (!fp_locks) {
>> +		pr_err("Can't open %s\n", path);
>>  		return -1;
>> -
>> -	test_msg("C: %d/%d\n", pid, alt_pid);
>> +	}
>>  
>>  	while (fgets(buf, sizeof(buf), fp_locks)) {
>> -		test_msg("c: %s", buf);
>> -
>> -		if (strstr(buf, "->"))
>> +		if (strncmp(buf, "lock:\t", 6) != 0)
>>  			continue;
>> +		test_msg("c: %s", buf);
>>  
>>  		num = sscanf(buf,
>> -			"%*d:%s %s %s %d %*02x:%*02x:%*d %*d %*s",
>> +			"%*s %*d:%s %s %s %d %*02x:%*02x:%*d %*d %*s",
>>  			fl_flag, fl_type, fl_option, &fl_owner);
>>  
>>  		if (num < 4) {
>> @@ -44,8 +45,10 @@ static int check_file_locks(int alt_pid, int fd)
>>  			break;
>>  		}
>>  
>> -		if (fl_owner != pid && fl_owner != alt_pid)
>> +		if (fl_owner != child_pid && fl_owner != getpid()) {
>> +			pr_err("Wrong owner\n");
>>  			continue;
>> +		}
>>  
>>  		if (!strcmp(fl_flag, "FLOCK") &&
>>  				!strcmp(fl_type, "ADVISORY") &&
>> @@ -67,11 +70,11 @@ static int check_file_locks(int alt_pid, int fd)
>>  
>>  int main(int argc, char **argv)
>>  {
>> -	int fd, pid;
>> +	int fd, child_fd, pid, ret;
>>  
>>  	test_init(argc, argv);
>>  
>> -	fd = open(filename, O_CREAT | O_RDWR, 0600);
>> +	fd = child_fd = open(filename, O_CREAT | O_RDWR, 0600);
>>  	if (fd < 0) {
>>  		pr_perror("No file");
>>  		return -1;
>> @@ -105,11 +108,12 @@ int main(int argc, char **argv)
>>  	test_daemon();
>>  	test_waitsig();
>>  
>> -	if (check_file_locks(pid, fd))
>> +	if (check_file_locks(pid, fd, child_fd) > 0)
>>  		pass();
>>  	else
>>  		fail("Flock file locks check failed");
>>  
>> +out_kill:
>>  	kill(pid, SIGTERM);
>>  	waitpid(pid, NULL, 0);
>>  	close(fd);
>>