[CRIU] [PATCH v2] zdtm: Make file_locks04 test based on /proc/{pid}/fdinfo/{fd}

[Pavel Emelyanov]

Andrey, would you ack/nack this patch?

On 06/28/2016 10:08 PM, Kirill Tkhai wrote:
> /proc/locks is racy with adding/removing locks,
> so we may lose lock on check.
> 
> Use fdinfo's list of locks instead.
> 
> v2: Feature 'fdinfo_lock'
> 
> Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
> ---
>  test/zdtm/static/file_locks04.c    |   31 +++++++++++++++++--------------
>  test/zdtm/static/file_locks04.desc |    2 +-
>  2 files changed, 18 insertions(+), 15 deletions(-)
> 
> diff --git a/test/zdtm/static/file_locks04.c b/test/zdtm/static/file_locks04.c
> index 995dd09..28ed497 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;
>  
>  	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;
> @@ -105,7 +108,7 @@ 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");
> diff --git a/test/zdtm/static/file_locks04.desc b/test/zdtm/static/file_locks04.desc
> index 80cd04e..41aad3f 100644
> --- a/test/zdtm/static/file_locks04.desc
> +++ b/test/zdtm/static/file_locks04.desc
> @@ -1 +1 @@
> -{'flags': 'excl', 'opts': '--file-locks'}
> +{'flags': 'excl', 'opts': '--file-locks', 'feature': 'fdinfo_lock'}
> 
> _______________________________________________
> CRIU mailing list
> CRIU at openvz.org
> https://lists.openvz.org/mailman/listinfo/criu
> .
>