/* move_mount test.
*
* Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
* Written by David Howells ([email protected])
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#define _GNU_SOURCE
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/prctl.h>
#include <sys/wait.h>
#define O_CLONE_MOUNT 040000000 /* Used with O_PATH to clone the mount
subtree at path */
#define O_NON_RECURSIVE 0100000000 /* Used with O_CLONE_MOUNT to only
clone one mount */
#define MOVE_MOUNT_F_SYMLINKS 0x00000001 /* Follow symlinks on from
path */
#define MOVE_MOUNT_F_AUTOMOUNTS 0x00000002 /* Follow automounts on from
path */
#define MOVE_MOUNT_F_EMPTY_PATH 0x00000004 /* Empty from path permitted
*/
#define MOVE_MOUNT_T_SYMLINKS 0x00000010 /* Follow symlinks on to
path */
#define MOVE_MOUNT_T_AUTOMOUNTS 0x00000020 /* Follow automounts on to
path */
#define MOVE_MOUNT_T_EMPTY_PATH 0x00000040 /* Empty to path permitted */
#define MOVE_MOUNT__MASK 0x00000077
static inline int move_mount(int from_dfd, const char *from_pathname,
int to_dfd, const char *to_pathname,
unsigned int flags)
{
return syscall(337, from_dfd, from_pathname, to_dfd, to_pathname,
flags);
}
void format(void)
{
printf("Format: move_mount [-a] [-c] [-r]\n");
exit(2);
}
int main(int argc, char *argv[])
{
bool preopen = false;
int ret, fd;
int o_flags = O_PATH;
if (argc < 3)
format();
for (; argc > 3; argc--, argv++) {
if (strcmp(argv[1], "-a") == 0)
preopen = true;
else if (strcmp(argv[1], "-c") == 0)
o_flags |= O_CLONE_MOUNT;
else if (strcmp(argv[1], "-r") == 0)
o_flags |= O_NON_RECURSIVE;
else
format();
}
if (preopen) {
fd = open(argv[1], o_flags);
if (fd < 0) {
fprintf(stderr, "open(%s, O_PATH|...): %m\n", argv[1]);
exit(1);
}
ret = move_mount(fd, "", AT_FDCWD, argv[2],
MOVE_MOUNT_F_EMPTY_PATH);
if (ret != 0) {
fprintf(stderr, "move_mount([%s],%s) = %d: %m\n",
argv[1], argv[2], ret);
exit(1);
}
} else {
ret = move_mount(AT_FDCWD, argv[1], AT_FDCWD, argv[2],
MOVE_MOUNT_F_EMPTY_PATH);
if (ret != 0) {
fprintf(stderr, "move_mount(%s,%s) = %d: %m\n",
argv[1], argv[2], ret);
exit(1);
}
}
exit(0);
}
