Skip a standard destriptor only if it's tty (v2)

ZDTM tests redirect standart descriptors to /dev/null

v2: * Skip tty only if it's a standard descriptor.
    * No strcmps on names.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>

cr-dump.c

@@ -219,34 +219,6 @@ err:
 	return ret;
 }
 
-static bool should_ignore_fd(char *pid_fd_dir, int dir, char *fd_name)
-{
-	if (!strcmp(fd_name, "0")) {
-		pr_info("... Skipping stdin ...\n");
-		return true;
-	} else if (!strcmp(fd_name, "1")) {
-		pr_info("... Skipping stdout ...\n");
-		return true;
-	} else if (!strcmp(fd_name, "2")) {
-		pr_info("... Skipping stderr ...\n");
-		return true;
-	} else {
-		char ttybuf[32];
-
-		if (readlinkat(dir, fd_name, ttybuf, sizeof(ttybuf)) > 0) {
-			if (!strncmp(ttybuf, "/dev/tty", 8)) {
-				pr_info("... Skipping tty ...\n");
-				return true;
-			}
-		} else {
-			pr_perror("Failed to readlink %s/%d %s\n", pid_fd_dir, dir, fd_name);
-			return false;
-		}
-	}
-
-	return false;
-}
-
 static int dump_one_fd(char *pid_fd_dir, int dir, char *fd_name, unsigned long pos,
 		       unsigned int flags, struct cr_fdset *cr_fdset)
 {
@@ -254,9 +226,6 @@ static int dump_one_fd(char *pid_fd_dir, int dir, char *fd_name, unsigned long p
 	struct stat st_buf;
 	int fd;
 
-	if (should_ignore_fd(pid_fd_dir, dir, fd_name))
-		return 0;
-
 	fd = openat(dir, fd_name, O_RDONLY);
 	if (fd < 0) {
 		pr_perror("Failed to openat %s/%d %s\n", pid_fd_dir, dir, fd_name);
@@ -268,6 +237,17 @@ static int dump_one_fd(char *pid_fd_dir, int dir, char *fd_name, unsigned long p
 		return -1;
 	}
 
+	if (S_ISCHR(st_buf.st_mode) &&
+		( major(st_buf.st_rdev) == TTY_MAJOR ||
+		  major(st_buf.st_rdev) == UNIX98_PTY_SLAVE_MAJOR)) {
+		/* skip only standard destriptors */
+		if (atoi(fd_name) < 3) {
+			pr_info("... Skipping tty ... %s/%s\n", pid_fd_dir, fd_name);
+			return 0;
+		}
+		goto err;
+	}
+
 	if (S_ISREG(st_buf.st_mode))
 		return dump_one_reg_file(FDINFO_FD, atol(fd_name),
 					 fd, 1, pos, flags, cr_fdset);
@@ -283,6 +263,7 @@ static int dump_one_fd(char *pid_fd_dir, int dir, char *fd_name, unsigned long p
 					     st_buf.st_ino, flags, cr_fdset);
 	}
 
+err:
 	pr_err("Can't dump file %s of that type [%x]\n", fd_name, st_buf.st_mode);
 	return 1;
 }