[thirdparty/util-linux.git] / include / mount-api-utils.h

/*
 * No copyright is claimed.  This code is in the public domain; do with
 * it what you wish.
 */
#ifndef UTIL_LINUX_MOUNT_API_UTILS
#define UTIL_LINUX_MOUNT_API_UTILS

#ifdef HAVE_LINUX_MOUNT_H
#include <sys/mount.h>
#include <linux/mount.h>
#include <linux/unistd.h>
#include <sys/syscall.h>
#include <inttypes.h>

/*
 * File descritors based mount API
 */
#ifdef HAVE_MOUNTFD_API

/* Accepted by both open_tree() and mount_setattr(). */
#ifndef AT_RECURSIVE
# define AT_RECURSIVE 0x8000
#endif

#ifndef OPEN_TREE_CLONE
# define OPEN_TREE_CLONE 1
#endif

#ifndef OPEN_TREE_CLOEXEC
# define OPEN_TREE_CLOEXEC O_CLOEXEC
#endif

#if !defined(HAVE_OPEN_TREE) && defined(SYS_open_tree)
static inline int open_tree(int dfd, const char *filename, unsigned int flags)
{
	return syscall(SYS_open_tree, dfd, filename, flags);
}
#endif

#ifndef MOVE_MOUNT_F_SYMLINKS
# define MOVE_MOUNT_F_SYMLINKS   0x00000001 /* Follow symlinks on from path */
#endif

#ifndef MOVE_MOUNT_F_AUTOMOUNTS
# define MOVE_MOUNT_F_AUTOMOUNTS 0x00000002 /* Follow automounts on from path */
#endif

#ifndef MOVE_MOUNT_F_EMPTY_PATH
# define MOVE_MOUNT_F_EMPTY_PATH 0x00000004 /* Empty from path permitted */
#endif

#ifndef MOVE_MOUNT_T_SYMLINKS
# define MOVE_MOUNT_T_SYMLINKS   0x00000010 /* Follow symlinks on to path */
#endif

#ifndef MOVE_MOUNT_T_AUTOMOUNTS
# define MOVE_MOUNT_T_AUTOMOUNTS 0x00000020 /* Follow automounts on to path */
#endif

#ifndef MOVE_MOUNT_T_EMPTY_PATH
# define MOVE_MOUNT_T_EMPTY_PATH 0x00000040 /* Empty to path permitted */
#endif

#ifndef MOVE_MOUNT_SET_GROUP
# define MOVE_MOUNT_SET_GROUP    0x00000100 /* Set sharing group instead */
#endif

#ifndef MOVE_MOUNT__MASK
# define MOVE_MOUNT__MASK 0x00000077
#endif

#if !defined(HAVE_MOVE_MOUNT) && defined(SYS_move_mount)
static inline int move_mount(int from_dfd, const char *from_pathname, int to_dfd,
			     const char *to_pathname, unsigned int flags)
{
	return syscall(SYS_move_mount, from_dfd, from_pathname, to_dfd,
		       to_pathname, flags);
}
#endif

#ifndef MOUNT_ATTR_RDONLY
# define MOUNT_ATTR_RDONLY 0x00000001
#endif

#ifndef MOUNT_ATTR_NOSUID
# define MOUNT_ATTR_NOSUID 0x00000002
#endif

#ifndef MOUNT_ATTR_NODEV
# define MOUNT_ATTR_NODEV 0x00000004
#endif

#ifndef MOUNT_ATTR_NOEXEC
# define MOUNT_ATTR_NOEXEC 0x00000008
#endif

#ifndef MOUNT_ATTR__ATIME
# define MOUNT_ATTR__ATIME 0x00000070
#endif

#ifndef MOUNT_ATTR_RELATIME
# define MOUNT_ATTR_RELATIME 0x00000000
#endif

#ifndef MOUNT_ATTR_NOATIME
# define MOUNT_ATTR_NOATIME 0x00000010
#endif

#ifndef MOUNT_ATTR_STRICTATIME
# define MOUNT_ATTR_STRICTATIME 0x00000020
#endif

#ifndef MOUNT_ATTR_NODIRATIME
# define MOUNT_ATTR_NODIRATIME 0x00000080
#endif

#ifndef MOUNT_ATTR_IDMAP
# define MOUNT_ATTR_IDMAP 0x00100000
#endif

#ifndef MOUNT_ATTR_NOSYMFOLLOW
# define MOUNT_ATTR_NOSYMFOLLOW 0x00200000
#endif

#ifndef HAVE_STRUCT_MOUNT_ATTR
# ifndef MOUNT_ATTR_SIZE_VER0 /* For case mount.h comes from a place invisible for autotools/meson */
# include <inttypes.h>
struct mount_attr {
	uint64_t attr_set;
	uint64_t attr_clr;
	uint64_t propagation;
	uint64_t userns_fd;
};
# endif
#endif

#if !defined(HAVE_MOUNT_SETATTR) && defined(SYS_mount_setattr)
static inline int mount_setattr(int dfd, const char *path, unsigned int flags,
				struct mount_attr *attr, size_t size)
{
	return syscall(SYS_mount_setattr, dfd, path, flags, attr, size);
}
#endif

#ifndef HAVE_ENUM_FSCONFIG_COMMAND
# ifndef FSOPEN_CLOEXEC /* For case mount.h comes from a place invisible for autotools/meson */
enum fsconfig_command {
	FSCONFIG_SET_FLAG	= 0,	/* Set parameter, supplying no value */
	FSCONFIG_SET_STRING	= 1,	/* Set parameter, supplying a string value */
	FSCONFIG_SET_BINARY	= 2,	/* Set parameter, supplying a binary blob value */
	FSCONFIG_SET_PATH	= 3,	/* Set parameter, supplying an object by path */
	FSCONFIG_SET_PATH_EMPTY	= 4,	/* Set parameter, supplying an object by (empty) path */
	FSCONFIG_SET_FD		= 5,	/* Set parameter, supplying an object by fd */
	FSCONFIG_CMD_CREATE	= 6,	/* Invoke superblock creation */
	FSCONFIG_CMD_RECONFIGURE = 7,	/* Invoke superblock reconfiguration */
};
# endif
#endif

#if !defined(HAVE_FSCONFIG) && defined(SYS_fsconfig)
static inline int fsconfig(int fd, unsigned int cmd, const char *key,
                    const void *value, int aux)
{
        return syscall(SYS_fsconfig, fd, cmd, key, value, aux);
}
#endif

#ifndef FSOPEN_CLOEXEC
# define FSOPEN_CLOEXEC          0x00000001
#endif

#if !defined(HAVE_FSOPEN) && defined(SYS_fsopen)
static inline int fsopen(const char *fsname, unsigned int flags)
{
        return syscall(SYS_fsopen, fsname, flags);
}
#endif

#ifndef FSMOUNT_CLOEXEC
# define FSMOUNT_CLOEXEC         0x00000001
#endif

#if !defined(HAVE_FSMOUNT) && defined(SYS_fsmount)
static inline int fsmount(int fd, unsigned int flags, unsigned int mount_attrs)
{
        return syscall(SYS_fsmount, fd, flags, mount_attrs);
}
#endif

#ifndef FSPICK_CLOEXEC
# define FSPICK_CLOEXEC          0x00000001
#endif

#ifndef FSPICK_SYMLINK_NOFOLLOW
# define FSPICK_SYMLINK_NOFOLLOW 0x00000002
#endif

#ifndef FSPICK_NO_AUTOMOUNT
# define FSPICK_NO_AUTOMOUNT     0x00000004
#endif

#ifdef FSPICK_EMPTY_PATH
# define FSPICK_EMPTY_PATH       0x00000008
#endif

#if !defined(HAVE_FSPICK) && defined(SYS_fspick)
static inline int fspick(int dfd, const char *pathname, unsigned int flags)
{
        return syscall(SYS_fspick, dfd, pathname, flags);
}
#endif

#endif /* HAVE_MOUNTFD_API */

/*
 * statmount() and listmount()
 */
#ifdef HAVE_STATMOUNT_API

#ifndef MNT_ID_REQ_SIZE_VER0
# define MNT_ID_REQ_SIZE_VER0    24 /* sizeof first published struct */
#endif
#ifndef MNT_ID_REQ_SIZE_VER1
# define MNT_ID_REQ_SIZE_VER1    32 /* sizeof second published struct */
#endif

/*
 * The structs mnt_id_req and statmount may differ between kernel versions, so
 * we must ensure that the structs contain everything we need. For now (during
 * development), it seems best to define local copies of the structs to avoid
 * relying on installed kernel headers and to avoid a storm of #ifdefs.
 */

/*
 * listmount() and statmount() request
 */
struct ul_mnt_id_req {
	uint32_t size;
	uint32_t spare;
	uint64_t mnt_id;
	uint64_t param;
	uint64_t mnt_ns_id;
};

/*
 * Please note that due to the variable length of the statmount buffer, the
 * struct cannot be versioned by size (like struct mnt_id_req).
 */
struct ul_statmount {
	uint32_t size;            /* Total size, including strings */
	uint32_t mnt_opts;        /* [str] Mount options of the mount */
	uint64_t mask;            /* What results were written */
	uint32_t sb_dev_major;    /* Device ID */
	uint32_t sb_dev_minor;
	uint64_t sb_magic;        /* ..._SUPER_MAGIC */
	uint32_t sb_flags;        /* SB_{RDONLY,SYNCHRONOUS,DIRSYNC,LAZYTIME} */
	uint32_t fs_type;         /* [str] Filesystem type */
	uint64_t mnt_id;          /* Unique ID of mount */
	uint64_t mnt_parent_id;   /* Unique ID of parent (for root == mnt_id) */
	uint32_t mnt_id_old;      /* Reused IDs used in proc/.../mountinfo */
	uint32_t mnt_parent_id_old;
	uint64_t mnt_attr;        /* MOUNT_ATTR_... */
	uint64_t mnt_propagation; /* MS_{SHARED,SLAVE,PRIVATE,UNBINDABLE} */
	uint64_t mnt_peer_group;  /* ID of shared peer group */
	uint64_t mnt_master;      /* Mount receives propagation from this ID */
	uint64_t propagate_from;  /* Propagation from in current namespace */
	uint32_t mnt_root;        /* [str] Root of mount relative to root of fs */
	uint32_t mnt_point;       /* [str] Mountpoint relative to current root */
	uint64_t mnt_ns_id;       /* ID of the mount namespace */
	uint32_t fs_subtype;      /* [str] Subtype of fs_type (if any) */
	uint32_t sb_source;       /* [str] Source string of the mount */
	uint32_t opt_num;         /* Number of fs options */
	uint32_t opt_array;       /* [str] Array of nul terminated fs options */
	uint32_t opt_sec_num;     /* Number of security options */
	uint32_t opt_sec_array;   /* [str] Array of nul terminated security options */
	uint64_t __spare2[46];
	char str[];               /* Variable size part containing strings */
};

/* sb_flags (defined in kernel include/linux/fs.h) */
#ifndef SB_RDONLY
# define SB_RDONLY       BIT(0)   /* Mount read-only */
# define SB_NOSUID       BIT(1)   /* Ignore suid and sgid bits */
# define SB_NODEV        BIT(2)   /* Disallow access to device special files */
# define SB_NOEXEC       BIT(3)   /* Disallow program execution */
# define SB_SYNCHRONOUS  BIT(4)   /* Writes are synced at once */
# define SB_MANDLOCK     BIT(6)   /* Allow mandatory locks on an FS */
# define SB_DIRSYNC      BIT(7)   /* Directory modifications are synchronous */
# define SB_NOATIME      BIT(10)  /* Do not update access times. */
# define SB_NODIRATIME   BIT(11)  /* Do not update directory access times */
# define SB_SILENT       BIT(15)
# define SB_POSIXACL     BIT(16)  /* Supports POSIX ACLs */
# define SB_INLINECRYPT  BIT(17)  /* Use blk-crypto for encrypted files */
# define SB_KERNMOUNT    BIT(22)  /* this is a kern_mount call */
# define SB_I_VERSION    BIT(23)  /* Update inode I_version field */
# define SB_LAZYTIME     BIT(25)  /* Update the on-disk [acm]times lazily */
#endif

/*
 * @mask bits for statmount(2)
 */
#ifndef STATMOUNT_SB_BASIC
# define STATMOUNT_SB_BASIC            0x00000001U   /* Want/got sb_... */
#endif
#ifndef STATMOUNT_MNT_BASIC
# define STATMOUNT_MNT_BASIC           0x00000002U   /* Want/got mnt_... */
#endif
#ifndef STATMOUNT_PROPAGATE_FROM
# define STATMOUNT_PROPAGATE_FROM      0x00000004U   /* Want/got propagate_from */
#endif
#ifndef STATMOUNT_MNT_ROOT
# define STATMOUNT_MNT_ROOT            0x00000008U   /* Want/got mnt_root  */
#endif
#ifndef STATMOUNT_MNT_POINT
# define STATMOUNT_MNT_POINT           0x00000010U   /* Want/got mnt_point */
#endif
#ifndef STATMOUNT_FS_TYPE
# define STATMOUNT_FS_TYPE             0x00000020U   /* Want/got fs_type */
#endif
#ifndef STATMOUNT_MNT_NS_ID
# define STATMOUNT_MNT_NS_ID           0x00000040U   /* Want/got mnt_ns_id */
#endif
#ifndef STATMOUNT_MNT_OPTS
# define STATMOUNT_MNT_OPTS            0x00000080U   /* Want/got mnt_opts */
#endif
#ifndef STATMOUNT_FS_SUBTYPE
# define STATMOUNT_FS_SUBTYPE          0x00000100U   /* Want/got fs_subtype */
#endif
#ifndef STATMOUNT_SB_SOURCE
# define STATMOUNT_SB_SOURCE           0x00000200U   /* Want/got sb_source */
#endif
#ifndef STATMOUNT_OPT_ARRAY
# define STATMOUNT_OPT_ARRAY           0x00000400U   /* Want/got opt_... */
#endif
#ifndef STATMOUNT_OPT_SEC_ARRAY
# define STATMOUNT_OPT_SEC_ARRAY       0x00000800U   /* Want/got opt_sec... */
#endif


/*
 * Special @mnt_id values that can be passed to listmount
 */
#ifdef LSMT_ROOT
# define LSMT_ROOT              0xffffffffffffffff    /* root mount */
#endif

#ifndef LISTMOUNT_REVERSE
# define LISTMOUNT_REVERSE      BIT(0)               /* List later mounts first */
#endif

/* Don't use this "raw" version. See ul_statmount() below. */
#if defined(SYS_statmount)
static inline int ul_statmount_syscall(uint64_t mnt_id,
			uint64_t ns_id,
			uint64_t mask,
			struct ul_statmount *buf,
			size_t bufsize, unsigned int flags)
{
       struct ul_mnt_id_req req = {
		.size = MNT_ID_REQ_SIZE_VER1,
		.mnt_id = mnt_id,
		.param = mask,
		.mnt_ns_id = ns_id
       };

       return syscall(SYS_statmount, &req, buf, bufsize, flags);
}

static inline int has_statmount(void)
{
	errno = 0;

	if (ul_statmount_syscall(0, 0, 0, NULL, 0, 0) < 0 && errno == ENOSYS)
		return 0;
	return 1;
}

/* This is a version of statmount() that reallocates @buf to be large enough to
 * store data for the requested @id. This function never deallocates; it is the
 * caller's responsibility.
 */
static inline int ul_statmount(uint64_t id,
			uint64_t ns_id,
			uint64_t mask,
			struct ul_statmount **buf,
			size_t *bufsiz,
			unsigned int flags)
{
	size_t sz;
	int rc = 0;

	if (!buf || !bufsiz)
		return -EINVAL;

	sz = *bufsiz;
	if (!sz)
		sz = 32 * 1024;

	do {
		if (sz > *bufsiz) {
			struct ul_statmount *tmp = realloc(*buf, sz);
			if (!tmp)
				return -ENOMEM;
			*buf = tmp;
			*bufsiz = sz;
		}

		errno = 0;
		rc = ul_statmount_syscall(id, ns_id, mask, *buf, *bufsiz, flags);
		if (!rc)
			break;
		if (errno != EOVERFLOW)
			break;
		if (sz >= SIZE_MAX / 2)
			break;
		sz <<= 1;
	} while (rc);

	return rc;
}
#endif /* SYS_statmount */


#if defined(SYS_listmount)
static inline ssize_t ul_listmount(uint64_t mnt_id,
			uint64_t ns_id,
			uint64_t last_mnt_id,
			uint64_t list[], size_t num,
			unsigned int flags)
{
       struct ul_mnt_id_req req = {
		.size = MNT_ID_REQ_SIZE_VER1,
		.mnt_id = mnt_id,
		.param = last_mnt_id,
		.mnt_ns_id = ns_id
       };

       return syscall(SYS_listmount, &req, list, num, flags);
}

static inline int has_listmount(void)
{
	uint64_t dummy;

	errno = 0;

	if (ul_listmount(LSMT_ROOT, 0, 0, &dummy, 1, LISTMOUNT_REVERSE) != 1)
		return 0;
	return 1;
}
#endif

#endif /* HAVE_STATMOUNT_API */

#endif /* HAVE_LINUX_MOUNT_H */

#endif /* UTIL_LINUX_MOUNT_API_UTILS */
Commit	Line	Data
	1	/*
	2	* No copyright is claimed. This code is in the public domain; do with
	3	* it what you wish.
	4	*/
	5	#ifndef UTIL_LINUX_MOUNT_API_UTILS
	6	#define UTIL_LINUX_MOUNT_API_UTILS
	7
	8	#ifdef HAVE_LINUX_MOUNT_H
	9	#include <sys/mount.h>
	10	#include <linux/mount.h>
	11	#include <linux/unistd.h>
	12	#include <sys/syscall.h>
	13	#include <inttypes.h>
	14
	15	/*
	16	* File descritors based mount API
	17	*/
	18	#ifdef HAVE_MOUNTFD_API
	19
	20	/* Accepted by both open_tree() and mount_setattr(). */
	21	#ifndef AT_RECURSIVE
	22	# define AT_RECURSIVE 0x8000
	23	#endif
	24
	25	#ifndef OPEN_TREE_CLONE
	26	# define OPEN_TREE_CLONE 1
	27	#endif
	28
	29	#ifndef OPEN_TREE_CLOEXEC
	30	# define OPEN_TREE_CLOEXEC O_CLOEXEC
	31	#endif
	32
	33	#if !defined(HAVE_OPEN_TREE) && defined(SYS_open_tree)
	34	static inline int open_tree(int dfd, const char *filename, unsigned int flags)
	35	{
	36	return syscall(SYS_open_tree, dfd, filename, flags);
	37	}
	38	#endif
	39
	40	#ifndef MOVE_MOUNT_F_SYMLINKS
	41	# define MOVE_MOUNT_F_SYMLINKS 0x00000001 /* Follow symlinks on from path */
	42	#endif
	43
	44	#ifndef MOVE_MOUNT_F_AUTOMOUNTS
	45	# define MOVE_MOUNT_F_AUTOMOUNTS 0x00000002 /* Follow automounts on from path */
	46	#endif
	47
	48	#ifndef MOVE_MOUNT_F_EMPTY_PATH
	49	# define MOVE_MOUNT_F_EMPTY_PATH 0x00000004 /* Empty from path permitted */
	50	#endif
	51
	52	#ifndef MOVE_MOUNT_T_SYMLINKS
	53	# define MOVE_MOUNT_T_SYMLINKS 0x00000010 /* Follow symlinks on to path */
	54	#endif
	55
	56	#ifndef MOVE_MOUNT_T_AUTOMOUNTS
	57	# define MOVE_MOUNT_T_AUTOMOUNTS 0x00000020 /* Follow automounts on to path */
	58	#endif
	59
	60	#ifndef MOVE_MOUNT_T_EMPTY_PATH
	61	# define MOVE_MOUNT_T_EMPTY_PATH 0x00000040 /* Empty to path permitted */
	62	#endif
	63
	64	#ifndef MOVE_MOUNT_SET_GROUP
	65	# define MOVE_MOUNT_SET_GROUP 0x00000100 /* Set sharing group instead */
	66	#endif
	67
	68	#ifndef MOVE_MOUNT__MASK
	69	# define MOVE_MOUNT__MASK 0x00000077
	70	#endif
	71
	72	#if !defined(HAVE_MOVE_MOUNT) && defined(SYS_move_mount)
	73	static inline int move_mount(int from_dfd, const char *from_pathname, int to_dfd,
	74	const char *to_pathname, unsigned int flags)
	75	{
	76	return syscall(SYS_move_mount, from_dfd, from_pathname, to_dfd,
	77	to_pathname, flags);
	78	}
	79	#endif
	80
	81	#ifndef MOUNT_ATTR_RDONLY
	82	# define MOUNT_ATTR_RDONLY 0x00000001
	83	#endif
	84
	85	#ifndef MOUNT_ATTR_NOSUID
	86	# define MOUNT_ATTR_NOSUID 0x00000002
	87	#endif
	88
	89	#ifndef MOUNT_ATTR_NODEV
	90	# define MOUNT_ATTR_NODEV 0x00000004
	91	#endif
	92
	93	#ifndef MOUNT_ATTR_NOEXEC
	94	# define MOUNT_ATTR_NOEXEC 0x00000008
	95	#endif
	96
	97	#ifndef MOUNT_ATTR__ATIME
	98	# define MOUNT_ATTR__ATIME 0x00000070
	99	#endif
	100
	101	#ifndef MOUNT_ATTR_RELATIME
	102	# define MOUNT_ATTR_RELATIME 0x00000000
	103	#endif
	104
	105	#ifndef MOUNT_ATTR_NOATIME
	106	# define MOUNT_ATTR_NOATIME 0x00000010
	107	#endif
	108
	109	#ifndef MOUNT_ATTR_STRICTATIME
	110	# define MOUNT_ATTR_STRICTATIME 0x00000020
	111	#endif
	112
	113	#ifndef MOUNT_ATTR_NODIRATIME
	114	# define MOUNT_ATTR_NODIRATIME 0x00000080
	115	#endif
	116
	117	#ifndef MOUNT_ATTR_IDMAP
	118	# define MOUNT_ATTR_IDMAP 0x00100000
	119	#endif
	120
	121	#ifndef MOUNT_ATTR_NOSYMFOLLOW
	122	# define MOUNT_ATTR_NOSYMFOLLOW 0x00200000
	123	#endif
	124
	125	#ifndef HAVE_STRUCT_MOUNT_ATTR
	126	# ifndef MOUNT_ATTR_SIZE_VER0 /* For case mount.h comes from a place invisible for autotools/meson */
	127	# include <inttypes.h>
	128	struct mount_attr {
	129	uint64_t attr_set;
	130	uint64_t attr_clr;
	131	uint64_t propagation;
	132	uint64_t userns_fd;
	133	};
	134	# endif
	135	#endif
	136
	137	#if !defined(HAVE_MOUNT_SETATTR) && defined(SYS_mount_setattr)
	138	static inline int mount_setattr(int dfd, const char *path, unsigned int flags,
	139	struct mount_attr *attr, size_t size)
	140	{
	141	return syscall(SYS_mount_setattr, dfd, path, flags, attr, size);
	142	}
	143	#endif
	144
	145	#ifndef HAVE_ENUM_FSCONFIG_COMMAND
	146	# ifndef FSOPEN_CLOEXEC /* For case mount.h comes from a place invisible for autotools/meson */
	147	enum fsconfig_command {
	148	FSCONFIG_SET_FLAG = 0, /* Set parameter, supplying no value */
	149	FSCONFIG_SET_STRING = 1, /* Set parameter, supplying a string value */
	150	FSCONFIG_SET_BINARY = 2, /* Set parameter, supplying a binary blob value */
	151	FSCONFIG_SET_PATH = 3, /* Set parameter, supplying an object by path */
	152	FSCONFIG_SET_PATH_EMPTY = 4, /* Set parameter, supplying an object by (empty) path */
	153	FSCONFIG_SET_FD = 5, /* Set parameter, supplying an object by fd */
	154	FSCONFIG_CMD_CREATE = 6, /* Invoke superblock creation */
	155	FSCONFIG_CMD_RECONFIGURE = 7, /* Invoke superblock reconfiguration */
	156	};
	157	# endif
	158	#endif
	159
	160	#if !defined(HAVE_FSCONFIG) && defined(SYS_fsconfig)
	161	static inline int fsconfig(int fd, unsigned int cmd, const char *key,
	162	const void *value, int aux)
	163	{
	164	return syscall(SYS_fsconfig, fd, cmd, key, value, aux);
	165	}
	166	#endif
	167
	168	#ifndef FSOPEN_CLOEXEC
	169	# define FSOPEN_CLOEXEC 0x00000001
	170	#endif
	171
	172	#if !defined(HAVE_FSOPEN) && defined(SYS_fsopen)
	173	static inline int fsopen(const char *fsname, unsigned int flags)
	174	{
	175	return syscall(SYS_fsopen, fsname, flags);
	176	}
	177	#endif
	178
	179	#ifndef FSMOUNT_CLOEXEC
	180	# define FSMOUNT_CLOEXEC 0x00000001
	181	#endif
	182
	183	#if !defined(HAVE_FSMOUNT) && defined(SYS_fsmount)
	184	static inline int fsmount(int fd, unsigned int flags, unsigned int mount_attrs)
	185	{
	186	return syscall(SYS_fsmount, fd, flags, mount_attrs);
	187	}
	188	#endif
	189
	190	#ifndef FSPICK_CLOEXEC
	191	# define FSPICK_CLOEXEC 0x00000001
	192	#endif
	193
	194	#ifndef FSPICK_SYMLINK_NOFOLLOW
	195	# define FSPICK_SYMLINK_NOFOLLOW 0x00000002
	196	#endif
	197
	198	#ifndef FSPICK_NO_AUTOMOUNT
	199	# define FSPICK_NO_AUTOMOUNT 0x00000004
	200	#endif
	201
	202	#ifdef FSPICK_EMPTY_PATH
	203	# define FSPICK_EMPTY_PATH 0x00000008
	204	#endif
	205
	206	#if !defined(HAVE_FSPICK) && defined(SYS_fspick)
	207	static inline int fspick(int dfd, const char *pathname, unsigned int flags)
	208	{
	209	return syscall(SYS_fspick, dfd, pathname, flags);
	210	}
	211	#endif
	212
	213	#endif /* HAVE_MOUNTFD_API */
	214
	215	/*
	216	* statmount() and listmount()
	217	*/
	218	#ifdef HAVE_STATMOUNT_API
	219
	220	#ifndef MNT_ID_REQ_SIZE_VER0
	221	# define MNT_ID_REQ_SIZE_VER0 24 /* sizeof first published struct */
	222	#endif
	223	#ifndef MNT_ID_REQ_SIZE_VER1
	224	# define MNT_ID_REQ_SIZE_VER1 32 /* sizeof second published struct */
	225	#endif
	226
	227	/*
	228	* The structs mnt_id_req and statmount may differ between kernel versions, so
	229	* we must ensure that the structs contain everything we need. For now (during
	230	* development), it seems best to define local copies of the structs to avoid
	231	* relying on installed kernel headers and to avoid a storm of #ifdefs.
	232	*/
	233
	234	/*
	235	* listmount() and statmount() request
	236	*/
	237	struct ul_mnt_id_req {
	238	uint32_t size;
	239	uint32_t spare;
	240	uint64_t mnt_id;
	241	uint64_t param;
	242	uint64_t mnt_ns_id;
	243	};
	244
	245	/*
	246	* Please note that due to the variable length of the statmount buffer, the
	247	* struct cannot be versioned by size (like struct mnt_id_req).
	248	*/
	249	struct ul_statmount {
	250	uint32_t size; /* Total size, including strings */
	251	uint32_t mnt_opts; /* [str] Mount options of the mount */
	252	uint64_t mask; /* What results were written */
	253	uint32_t sb_dev_major; /* Device ID */
	254	uint32_t sb_dev_minor;
	255	uint64_t sb_magic; /* ..._SUPER_MAGIC */
	256	uint32_t sb_flags; /* SB_{RDONLY,SYNCHRONOUS,DIRSYNC,LAZYTIME} */
	257	uint32_t fs_type; /* [str] Filesystem type */
	258	uint64_t mnt_id; /* Unique ID of mount */
	259	uint64_t mnt_parent_id; /* Unique ID of parent (for root == mnt_id) */
	260	uint32_t mnt_id_old; /* Reused IDs used in proc/.../mountinfo */
	261	uint32_t mnt_parent_id_old;
	262	uint64_t mnt_attr; /* MOUNT_ATTR_... */
	263	uint64_t mnt_propagation; /* MS_{SHARED,SLAVE,PRIVATE,UNBINDABLE} */
	264	uint64_t mnt_peer_group; /* ID of shared peer group */
	265	uint64_t mnt_master; /* Mount receives propagation from this ID */
	266	uint64_t propagate_from; /* Propagation from in current namespace */
	267	uint32_t mnt_root; /* [str] Root of mount relative to root of fs */
	268	uint32_t mnt_point; /* [str] Mountpoint relative to current root */
	269	uint64_t mnt_ns_id; /* ID of the mount namespace */
	270	uint32_t fs_subtype; /* [str] Subtype of fs_type (if any) */
	271	uint32_t sb_source; /* [str] Source string of the mount */
	272	uint32_t opt_num; /* Number of fs options */
	273	uint32_t opt_array; /* [str] Array of nul terminated fs options */
	274	uint32_t opt_sec_num; /* Number of security options */
	275	uint32_t opt_sec_array; /* [str] Array of nul terminated security options */
	276	uint64_t __spare2[46];
	277	char str[]; /* Variable size part containing strings */
	278	};
	279
	280	/* sb_flags (defined in kernel include/linux/fs.h) */
	281	#ifndef SB_RDONLY
	282	# define SB_RDONLY BIT(0) /* Mount read-only */
	283	# define SB_NOSUID BIT(1) /* Ignore suid and sgid bits */
	284	# define SB_NODEV BIT(2) /* Disallow access to device special files */
	285	# define SB_NOEXEC BIT(3) /* Disallow program execution */
	286	# define SB_SYNCHRONOUS BIT(4) /* Writes are synced at once */
	287	# define SB_MANDLOCK BIT(6) /* Allow mandatory locks on an FS */
	288	# define SB_DIRSYNC BIT(7) /* Directory modifications are synchronous */
	289	# define SB_NOATIME BIT(10) /* Do not update access times. */
	290	# define SB_NODIRATIME BIT(11) /* Do not update directory access times */
	291	# define SB_SILENT BIT(15)
	292	# define SB_POSIXACL BIT(16) /* Supports POSIX ACLs */
	293	# define SB_INLINECRYPT BIT(17) /* Use blk-crypto for encrypted files */
	294	# define SB_KERNMOUNT BIT(22) /* this is a kern_mount call */
	295	# define SB_I_VERSION BIT(23) /* Update inode I_version field */
	296	# define SB_LAZYTIME BIT(25) /* Update the on-disk [acm]times lazily */
	297	#endif
	298
	299	/*
	300	* @mask bits for statmount(2)
	301	*/
	302	#ifndef STATMOUNT_SB_BASIC
	303	# define STATMOUNT_SB_BASIC 0x00000001U /* Want/got sb_... */
	304	#endif
	305	#ifndef STATMOUNT_MNT_BASIC
	306	# define STATMOUNT_MNT_BASIC 0x00000002U /* Want/got mnt_... */
	307	#endif
	308	#ifndef STATMOUNT_PROPAGATE_FROM
	309	# define STATMOUNT_PROPAGATE_FROM 0x00000004U /* Want/got propagate_from */
	310	#endif
	311	#ifndef STATMOUNT_MNT_ROOT
	312	# define STATMOUNT_MNT_ROOT 0x00000008U /* Want/got mnt_root */
	313	#endif
	314	#ifndef STATMOUNT_MNT_POINT
	315	# define STATMOUNT_MNT_POINT 0x00000010U /* Want/got mnt_point */
	316	#endif
	317	#ifndef STATMOUNT_FS_TYPE
	318	# define STATMOUNT_FS_TYPE 0x00000020U /* Want/got fs_type */
	319	#endif
	320	#ifndef STATMOUNT_MNT_NS_ID
	321	# define STATMOUNT_MNT_NS_ID 0x00000040U /* Want/got mnt_ns_id */
	322	#endif
	323	#ifndef STATMOUNT_MNT_OPTS
	324	# define STATMOUNT_MNT_OPTS 0x00000080U /* Want/got mnt_opts */
	325	#endif
	326	#ifndef STATMOUNT_FS_SUBTYPE
	327	# define STATMOUNT_FS_SUBTYPE 0x00000100U /* Want/got fs_subtype */
	328	#endif
	329	#ifndef STATMOUNT_SB_SOURCE
	330	# define STATMOUNT_SB_SOURCE 0x00000200U /* Want/got sb_source */
	331	#endif
	332	#ifndef STATMOUNT_OPT_ARRAY
	333	# define STATMOUNT_OPT_ARRAY 0x00000400U /* Want/got opt_... */
	334	#endif
	335	#ifndef STATMOUNT_OPT_SEC_ARRAY
	336	# define STATMOUNT_OPT_SEC_ARRAY 0x00000800U /* Want/got opt_sec... */
	337	#endif
	338
	339
	340	/*
	341	* Special @mnt_id values that can be passed to listmount
	342	*/
	343	#ifdef LSMT_ROOT
	344	# define LSMT_ROOT 0xffffffffffffffff /* root mount */
	345	#endif
	346
	347	#ifndef LISTMOUNT_REVERSE
	348	# define LISTMOUNT_REVERSE BIT(0) /* List later mounts first */
	349	#endif
	350
	351	/* Don't use this "raw" version. See ul_statmount() below. */
	352	#if defined(SYS_statmount)
	353	static inline int ul_statmount_syscall(uint64_t mnt_id,
	354	uint64_t ns_id,
	355	uint64_t mask,
	356	struct ul_statmount *buf,
	357	size_t bufsize, unsigned int flags)
	358	{
	359	struct ul_mnt_id_req req = {
	360	.size = MNT_ID_REQ_SIZE_VER1,
	361	.mnt_id = mnt_id,
	362	.param = mask,
	363	.mnt_ns_id = ns_id
	364	};
	365
	366	return syscall(SYS_statmount, &req, buf, bufsize, flags);
	367	}
	368
	369	static inline int has_statmount(void)
	370	{
	371	errno = 0;
	372
	373	if (ul_statmount_syscall(0, 0, 0, NULL, 0, 0) < 0 && errno == ENOSYS)
	374	return 0;
	375	return 1;
	376	}
	377
	378	/* This is a version of statmount() that reallocates @buf to be large enough to
	379	* store data for the requested @id. This function never deallocates; it is the
	380	* caller's responsibility.
	381	*/
	382	static inline int ul_statmount(uint64_t id,
	383	uint64_t ns_id,
	384	uint64_t mask,
	385	struct ul_statmount **buf,
	386	size_t *bufsiz,
	387	unsigned int flags)
	388	{
	389	size_t sz;
	390	int rc = 0;
	391
	392	if (!buf \|\| !bufsiz)
	393	return -EINVAL;
	394
	395	sz = *bufsiz;
	396	if (!sz)
	397	sz = 32 * 1024;
	398
	399	do {
	400	if (sz > *bufsiz) {
	401	struct ul_statmount tmp = realloc(buf, sz);
	402	if (!tmp)
	403	return -ENOMEM;
	404	*buf = tmp;
	405	*bufsiz = sz;
	406	}
	407
	408	errno = 0;
	409	rc = ul_statmount_syscall(id, ns_id, mask, buf, bufsiz, flags);
	410	if (!rc)
	411	break;
	412	if (errno != EOVERFLOW)
	413	break;
	414	if (sz >= SIZE_MAX / 2)
	415	break;
	416	sz <<= 1;
	417	} while (rc);
	418
	419	return rc;
	420	}
	421	#endif /* SYS_statmount */
	422
	423
	424	#if defined(SYS_listmount)
	425	static inline ssize_t ul_listmount(uint64_t mnt_id,
	426	uint64_t ns_id,
	427	uint64_t last_mnt_id,
	428	uint64_t list[], size_t num,
	429	unsigned int flags)
	430	{
	431	struct ul_mnt_id_req req = {
	432	.size = MNT_ID_REQ_SIZE_VER1,
	433	.mnt_id = mnt_id,
	434	.param = last_mnt_id,
	435	.mnt_ns_id = ns_id
	436	};
	437
	438	return syscall(SYS_listmount, &req, list, num, flags);
	439	}
	440
	441	static inline int has_listmount(void)
	442	{
	443	uint64_t dummy;
	444
	445	errno = 0;
	446
	447	if (ul_listmount(LSMT_ROOT, 0, 0, &dummy, 1, LISTMOUNT_REVERSE) != 1)
	448	return 0;
	449	return 1;
	450	}
	451	#endif
	452
	453	#endif /* HAVE_STATMOUNT_API */
	454
	455	#endif /* HAVE_LINUX_MOUNT_H */
	456
	457	#endif /* UTIL_LINUX_MOUNT_API_UTILS */