root/tools/include/uapi/linux/mount.h
#ifndef _UAPI_LINUX_MOUNT_H
#define _UAPI_LINUX_MOUNT_H

#include <linux/types.h>

/*
 * These are the fs-independent mount-flags: up to 32 flags are supported
 *
 * Usage of these is restricted within the kernel to core mount(2) code and
 * callers of sys_mount() only.  Filesystems should be using the SB_*
 * equivalent instead.
 */
#define MS_RDONLY        1      /* Mount read-only */
#define MS_NOSUID        2      /* Ignore suid and sgid bits */
#define MS_NODEV         4      /* Disallow access to device special files */
#define MS_NOEXEC        8      /* Disallow program execution */
#define MS_SYNCHRONOUS  16      /* Writes are synced at once */
#define MS_REMOUNT      32      /* Alter flags of a mounted FS */
#define MS_MANDLOCK     64      /* Allow mandatory locks on an FS */
#define MS_DIRSYNC      128     /* Directory modifications are synchronous */
#define MS_NOSYMFOLLOW  256     /* Do not follow symlinks */
#define MS_NOATIME      1024    /* Do not update access times. */
#define MS_NODIRATIME   2048    /* Do not update directory access times */
#define MS_BIND         4096
#define MS_MOVE         8192
#define MS_REC          16384
#define MS_VERBOSE      32768   /* War is peace. Verbosity is silence.
                                   MS_VERBOSE is deprecated. */
#define MS_SILENT       32768
#define MS_POSIXACL     (1<<16) /* VFS does not apply the umask */
#define MS_UNBINDABLE   (1<<17) /* change to unbindable */
#define MS_PRIVATE      (1<<18) /* change to private */
#define MS_SLAVE        (1<<19) /* change to slave */
#define MS_SHARED       (1<<20) /* change to shared */
#define MS_RELATIME     (1<<21) /* Update atime relative to mtime/ctime. */
#define MS_KERNMOUNT    (1<<22) /* this is a kern_mount call */
#define MS_I_VERSION    (1<<23) /* Update inode I_version field */
#define MS_STRICTATIME  (1<<24) /* Always perform atime updates */
#define MS_LAZYTIME     (1<<25) /* Update the on-disk [acm]times lazily */

/* These sb flags are internal to the kernel */
#define MS_SUBMOUNT     (1<<26)
#define MS_NOREMOTELOCK (1<<27)
#define MS_NOSEC        (1<<28)
#define MS_BORN         (1<<29)
#define MS_ACTIVE       (1<<30)
#define MS_NOUSER       (1<<31)

/*
 * Superblock flags that can be altered by MS_REMOUNT
 */
#define MS_RMT_MASK     (MS_RDONLY|MS_SYNCHRONOUS|MS_MANDLOCK|MS_I_VERSION|\
                         MS_LAZYTIME)

/*
 * Old magic mount flag and mask
 */
#define MS_MGC_VAL 0xC0ED0000
#define MS_MGC_MSK 0xffff0000

/*
 * open_tree() flags.
 */
#define OPEN_TREE_CLONE         1               /* Clone the target tree and attach the clone */
#define OPEN_TREE_CLOEXEC       O_CLOEXEC       /* Close the file on execve() */

/*
 * move_mount() flags.
 */
#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_SET_GROUP            0x00000100 /* Set sharing group instead */
#define MOVE_MOUNT_BENEATH              0x00000200 /* Mount beneath top mount */
#define MOVE_MOUNT__MASK                0x00000377

/*
 * fsopen() flags.
 */
#define FSOPEN_CLOEXEC          0x00000001

/*
 * fspick() flags.
 */
#define FSPICK_CLOEXEC          0x00000001
#define FSPICK_SYMLINK_NOFOLLOW 0x00000002
#define FSPICK_NO_AUTOMOUNT     0x00000004
#define FSPICK_EMPTY_PATH       0x00000008

/*
 * The type of fsconfig() call made.
 */
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,    /* Create new or reuse existing superblock */
        FSCONFIG_CMD_RECONFIGURE = 7,   /* Invoke superblock reconfiguration */
        FSCONFIG_CMD_CREATE_EXCL = 8,   /* Create new superblock, fail if reusing existing superblock */
};

/*
 * fsmount() flags.
 */
#define FSMOUNT_CLOEXEC         0x00000001

/*
 * Mount attributes.
 */
#define MOUNT_ATTR_RDONLY       0x00000001 /* Mount read-only */
#define MOUNT_ATTR_NOSUID       0x00000002 /* Ignore suid and sgid bits */
#define MOUNT_ATTR_NODEV        0x00000004 /* Disallow access to device special files */
#define MOUNT_ATTR_NOEXEC       0x00000008 /* Disallow program execution */
#define MOUNT_ATTR__ATIME       0x00000070 /* Setting on how atime should be updated */
#define MOUNT_ATTR_RELATIME     0x00000000 /* - Update atime relative to mtime/ctime. */
#define MOUNT_ATTR_NOATIME      0x00000010 /* - Do not update access times. */
#define MOUNT_ATTR_STRICTATIME  0x00000020 /* - Always perform atime updates */
#define MOUNT_ATTR_NODIRATIME   0x00000080 /* Do not update directory access times */
#define MOUNT_ATTR_IDMAP        0x00100000 /* Idmap mount to @userns_fd in struct mount_attr. */
#define MOUNT_ATTR_NOSYMFOLLOW  0x00200000 /* Do not follow symlinks */

/*
 * mount_setattr()
 */
struct mount_attr {
        __u64 attr_set;
        __u64 attr_clr;
        __u64 propagation;
        __u64 userns_fd;
};

/* List of all mount_attr versions. */
#define MOUNT_ATTR_SIZE_VER0    32 /* sizeof first published struct */


/*
 * Structure for getting mount/superblock/filesystem info with statmount(2).
 *
 * The interface is similar to statx(2): individual fields or groups can be
 * selected with the @mask argument of statmount().  Kernel will set the @mask
 * field according to the supported fields.
 *
 * If string fields are selected, then the caller needs to pass a buffer that
 * has space after the fixed part of the structure.  Nul terminated strings are
 * copied there and offsets relative to @str are stored in the relevant fields.
 * If the buffer is too small, then EOVERFLOW is returned.  The actually used
 * size is returned in @size.
 */
struct statmount {
        __u32 size;             /* Total size, including strings */
        __u32 mnt_opts;         /* [str] Options (comma separated, escaped) */
        __u64 mask;             /* What results were written */
        __u32 sb_dev_major;     /* Device ID */
        __u32 sb_dev_minor;
        __u64 sb_magic;         /* ..._SUPER_MAGIC */
        __u32 sb_flags;         /* SB_{RDONLY,SYNCHRONOUS,DIRSYNC,LAZYTIME} */
        __u32 fs_type;          /* [str] Filesystem type */
        __u64 mnt_id;           /* Unique ID of mount */
        __u64 mnt_parent_id;    /* Unique ID of parent (for root == mnt_id) */
        __u32 mnt_id_old;       /* Reused IDs used in proc/.../mountinfo */
        __u32 mnt_parent_id_old;
        __u64 mnt_attr;         /* MOUNT_ATTR_... */
        __u64 mnt_propagation;  /* MS_{SHARED,SLAVE,PRIVATE,UNBINDABLE} */
        __u64 mnt_peer_group;   /* ID of shared peer group */
        __u64 mnt_master;       /* Mount receives propagation from this ID */
        __u64 propagate_from;   /* Propagation from in current namespace */
        __u32 mnt_root;         /* [str] Root of mount relative to root of fs */
        __u32 mnt_point;        /* [str] Mountpoint relative to current root */
        __u64 mnt_ns_id;        /* ID of the mount namespace */
        __u32 fs_subtype;       /* [str] Subtype of fs_type (if any) */
        __u32 sb_source;        /* [str] Source string of the mount */
        __u32 opt_num;          /* Number of fs options */
        __u32 opt_array;        /* [str] Array of nul terminated fs options */
        __u32 opt_sec_num;      /* Number of security options */
        __u32 opt_sec_array;    /* [str] Array of nul terminated security options */
        __u64 supported_mask;   /* Mask flags that this kernel supports */
        __u32 mnt_uidmap_num;   /* Number of uid mappings */
        __u32 mnt_uidmap;       /* [str] Array of uid mappings (as seen from callers namespace) */
        __u32 mnt_gidmap_num;   /* Number of gid mappings */
        __u32 mnt_gidmap;       /* [str] Array of gid mappings (as seen from callers namespace) */
        __u64 __spare2[43];
        char str[];             /* Variable size part containing strings */
};

/*
 * Structure for passing mount ID and miscellaneous parameters to statmount(2)
 * and listmount(2).
 *
 * For statmount(2) @param represents the request mask.
 * For listmount(2) @param represents the last listed mount id (or zero).
 */
struct mnt_id_req {
        __u32 size;
        __u32 spare;
        __u64 mnt_id;
        __u64 param;
        __u64 mnt_ns_id;
};

/* List of all mnt_id_req versions. */
#define MNT_ID_REQ_SIZE_VER0    24 /* sizeof first published struct */
#define MNT_ID_REQ_SIZE_VER1    32 /* sizeof second published struct */

/*
 * @mask bits for statmount(2)
 */
#define STATMOUNT_SB_BASIC              0x00000001U     /* Want/got sb_... */
#define STATMOUNT_MNT_BASIC             0x00000002U     /* Want/got mnt_... */
#define STATMOUNT_PROPAGATE_FROM        0x00000004U     /* Want/got propagate_from */
#define STATMOUNT_MNT_ROOT              0x00000008U     /* Want/got mnt_root  */
#define STATMOUNT_MNT_POINT             0x00000010U     /* Want/got mnt_point */
#define STATMOUNT_FS_TYPE               0x00000020U     /* Want/got fs_type */
#define STATMOUNT_MNT_NS_ID             0x00000040U     /* Want/got mnt_ns_id */
#define STATMOUNT_MNT_OPTS              0x00000080U     /* Want/got mnt_opts */
#define STATMOUNT_FS_SUBTYPE            0x00000100U     /* Want/got fs_subtype */
#define STATMOUNT_SB_SOURCE             0x00000200U     /* Want/got sb_source */
#define STATMOUNT_OPT_ARRAY             0x00000400U     /* Want/got opt_... */
#define STATMOUNT_OPT_SEC_ARRAY         0x00000800U     /* Want/got opt_sec... */
#define STATMOUNT_SUPPORTED_MASK        0x00001000U     /* Want/got supported mask flags */
#define STATMOUNT_MNT_UIDMAP            0x00002000U     /* Want/got uidmap... */
#define STATMOUNT_MNT_GIDMAP            0x00004000U     /* Want/got gidmap... */

/*
 * Special @mnt_id values that can be passed to listmount
 */
#define LSMT_ROOT               0xffffffffffffffff      /* root mount */
#define LISTMOUNT_REVERSE       (1 << 0) /* List later mounts first */

#endif /* _UAPI_LINUX_MOUNT_H */