1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * Author: Aleksa Sarai <cyphar@cyphar.com>
  4 * Copyright (C) 2018-2019 SUSE LLC.
  5 */
  6
  7#ifndef __RESOLVEAT_H__
  8#define __RESOLVEAT_H__
  9
 10#define _GNU_SOURCE
 11#include <stdint.h>
 12#include <stdbool.h>
 13#include <errno.h>
 14#include <linux/types.h>
 15#include "../kselftest.h"
 16
 17#define ARRAY_LEN(X) (sizeof (X) / sizeof (*(X)))
 18#define BUILD_BUG_ON(e) ((void)(sizeof(struct { int:(-!!(e)); })))
 19
 20#ifndef SYS_openat2
 21#ifndef __NR_openat2
 22#define __NR_openat2 437
 23#endif /* __NR_openat2 */
 24#define SYS_openat2 __NR_openat2
 25#endif /* SYS_openat2 */
 26
 27/*
 28 * Arguments for how openat2(2) should open the target path. If @resolve is
 29 * zero, then openat2(2) operates very similarly to openat(2).
 30 *
 31 * However, unlike openat(2), unknown bits in @flags result in -EINVAL rather
 32 * than being silently ignored. @mode must be zero unless one of {O_CREAT,
 33 * O_TMPFILE} are set.
 34 *
 35 * @flags: O_* flags.
 36 * @mode: O_CREAT/O_TMPFILE file mode.
 37 * @resolve: RESOLVE_* flags.
 38 */
 39struct open_how {
 40	__u64 flags;
 41	__u64 mode;
 42	__u64 resolve;
 43};
 44
 45#define OPEN_HOW_SIZE_VER0	24 /* sizeof first published struct */
 46#define OPEN_HOW_SIZE_LATEST	OPEN_HOW_SIZE_VER0
 47
 48bool needs_openat2(const struct open_how *how);
 49
 50#ifndef RESOLVE_IN_ROOT
 51/* how->resolve flags for openat2(2). */
 52#define RESOLVE_NO_XDEV		0x01 /* Block mount-point crossings
 53					(includes bind-mounts). */
 54#define RESOLVE_NO_MAGICLINKS	0x02 /* Block traversal through procfs-style
 55					"magic-links". */
 56#define RESOLVE_NO_SYMLINKS	0x04 /* Block traversal through all symlinks
 57					(implies OEXT_NO_MAGICLINKS) */
 58#define RESOLVE_BENEATH		0x08 /* Block "lexical" trickery like
 59					"..", symlinks, and absolute
 60					paths which escape the dirfd. */
 61#define RESOLVE_IN_ROOT		0x10 /* Make all jumps to "/" and ".."
 62					be scoped inside the dirfd
 63					(similar to chroot(2)). */
 64#endif /* RESOLVE_IN_ROOT */
 65
 66#define E_func(func, ...)						      \
 67	do {								      \
 68		errno = 0;						      \
 69		if (func(__VA_ARGS__) < 0)				      \
 70			ksft_exit_fail_msg("%s:%d %s failed - errno:%d\n",    \
 71					   __FILE__, __LINE__, #func, errno); \
 72	} while (0)
 73
 74#define E_asprintf(...)		E_func(asprintf,	__VA_ARGS__)
 75#define E_chmod(...)		E_func(chmod,		__VA_ARGS__)
 76#define E_dup2(...)		E_func(dup2,		__VA_ARGS__)
 77#define E_fchdir(...)		E_func(fchdir,		__VA_ARGS__)
 78#define E_fstatat(...)		E_func(fstatat,		__VA_ARGS__)
 79#define E_kill(...)		E_func(kill,		__VA_ARGS__)
 80#define E_mkdirat(...)		E_func(mkdirat,		__VA_ARGS__)
 81#define E_mount(...)		E_func(mount,		__VA_ARGS__)
 82#define E_prctl(...)		E_func(prctl,		__VA_ARGS__)
 83#define E_readlink(...)		E_func(readlink,	__VA_ARGS__)
 84#define E_setresuid(...)	E_func(setresuid,	__VA_ARGS__)
 85#define E_symlinkat(...)	E_func(symlinkat,	__VA_ARGS__)
 86#define E_touchat(...)		E_func(touchat,		__VA_ARGS__)
 87#define E_unshare(...)		E_func(unshare,		__VA_ARGS__)
 88
 89#define E_assert(expr, msg, ...)					\
 90	do {								\
 91		if (!(expr))						\
 92			ksft_exit_fail_msg("ASSERT(%s:%d) failed (%s): " msg "\n", \
 93					   __FILE__, __LINE__, #expr, ##__VA_ARGS__); \
 94	} while (0)
 95
 96int raw_openat2(int dfd, const char *path, void *how, size_t size);
 97int sys_openat2(int dfd, const char *path, struct open_how *how);
 98int sys_openat(int dfd, const char *path, struct open_how *how);
 99int sys_renameat2(int olddirfd, const char *oldpath,
100		  int newdirfd, const char *newpath, unsigned int flags);
101
102int touchat(int dfd, const char *path);
103char *fdreadlink(int fd);
104bool fdequal(int fd, int dfd, const char *path);
105
106extern bool openat2_supported;
107
108#endif /* __RESOLVEAT_H__ */