restore: Use vpid in log_init_by_pid() instead of getpid()

When task is in pid namespace, getpid() can't be used
to identify it. So, use vpid instead of that.

Also, move log_init_by_pid() above pid check.
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

criu/cr-restore.c

@@ -1550,6 +1550,10 @@ static int restore_task_with_children(void *_arg)
 	if (ret)
 		goto err;
 
+	ret = log_init_by_pid(vpid(current));
+	if (ret < 0)
+		goto err;
+
 	pid = getpid();
 	if (vpid(current) != pid) {
 		pr_err("Pid %d do not match expected %d\n", pid, vpid(current));
@@ -1557,10 +1561,6 @@ static int restore_task_with_children(void *_arg)
 		goto err;
 	}
 
-	ret = log_init_by_pid();
-	if (ret < 0)
-		goto err;
-
 	if (!(ca->clone_flags & CLONE_FILES)) {
 		ret = close_old_fds();
 		if (ret)

criu/include/criu-log.h

@@ -24,7 +24,7 @@
 
 extern int log_init(const char *output);
 extern void log_fini(void);
-extern int log_init_by_pid(void);
+extern int log_init_by_pid(pid_t pid);
 extern void log_closedir(void);
 extern int log_keep_err(void);
 extern char *log_first_err(void);

criu/log.c

@@ -171,7 +171,7 @@ err:
 	return -1;
 }
 
-int log_init_by_pid(void)
+int log_init_by_pid(pid_t pid)
 {
 	char path[PATH_MAX];
 
@@ -182,14 +182,14 @@ int log_init_by_pid(void)
 	reset_buf_off();
 
 	if (!opts.log_file_per_pid) {
-		buf_off += snprintf(buffer + buf_off, sizeof buffer - buf_off, "%6d: ", getpid());
+		buf_off += snprintf(buffer + buf_off, sizeof buffer - buf_off, "%6d: ", pid);
 		return 0;
 	}
 
 	if (!opts.output)
 		return 0;
 
-	snprintf(path, PATH_MAX, "%s.%d", opts.output, getpid());
+	snprintf(path, PATH_MAX, "%s.%d", opts.output, pid);
 
 	return log_init(path);
 }