root/tools/include/uapi/linux/fanotify.h
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
#ifndef _UAPI_LINUX_FANOTIFY_H
#define _UAPI_LINUX_FANOTIFY_H

#include <linux/types.h>

/* the following events that user-space can register for */
#define FAN_ACCESS              0x00000001      /* File was accessed */
#define FAN_MODIFY              0x00000002      /* File was modified */
#define FAN_ATTRIB              0x00000004      /* Metadata changed */
#define FAN_CLOSE_WRITE         0x00000008      /* Writable file closed */
#define FAN_CLOSE_NOWRITE       0x00000010      /* Unwritable file closed */
#define FAN_OPEN                0x00000020      /* File was opened */
#define FAN_MOVED_FROM          0x00000040      /* File was moved from X */
#define FAN_MOVED_TO            0x00000080      /* File was moved to Y */
#define FAN_CREATE              0x00000100      /* Subfile was created */
#define FAN_DELETE              0x00000200      /* Subfile was deleted */
#define FAN_DELETE_SELF         0x00000400      /* Self was deleted */
#define FAN_MOVE_SELF           0x00000800      /* Self was moved */
#define FAN_OPEN_EXEC           0x00001000      /* File was opened for exec */

#define FAN_Q_OVERFLOW          0x00004000      /* Event queued overflowed */
#define FAN_FS_ERROR            0x00008000      /* Filesystem error */

#define FAN_OPEN_PERM           0x00010000      /* File open in perm check */
#define FAN_ACCESS_PERM         0x00020000      /* File accessed in perm check */
#define FAN_OPEN_EXEC_PERM      0x00040000      /* File open/exec in perm check */
/* #define FAN_DIR_MODIFY       0x00080000 */   /* Deprecated (reserved) */

#define FAN_PRE_ACCESS          0x00100000      /* Pre-content access hook */
#define FAN_MNT_ATTACH          0x01000000      /* Mount was attached */
#define FAN_MNT_DETACH          0x02000000      /* Mount was detached */

#define FAN_EVENT_ON_CHILD      0x08000000      /* Interested in child events */

#define FAN_RENAME              0x10000000      /* File was renamed */

#define FAN_ONDIR               0x40000000      /* Event occurred against dir */

/* helper events */
#define FAN_CLOSE               (FAN_CLOSE_WRITE | FAN_CLOSE_NOWRITE) /* close */
#define FAN_MOVE                (FAN_MOVED_FROM | FAN_MOVED_TO) /* moves */

/* flags used for fanotify_init() */
#define FAN_CLOEXEC             0x00000001
#define FAN_NONBLOCK            0x00000002

/* These are NOT bitwise flags.  Both bits are used together.  */
#define FAN_CLASS_NOTIF         0x00000000
#define FAN_CLASS_CONTENT       0x00000004
#define FAN_CLASS_PRE_CONTENT   0x00000008

/* Deprecated - do not use this in programs and do not add new flags here! */
#define FAN_ALL_CLASS_BITS      (FAN_CLASS_NOTIF | FAN_CLASS_CONTENT | \
                                 FAN_CLASS_PRE_CONTENT)

#define FAN_UNLIMITED_QUEUE     0x00000010
#define FAN_UNLIMITED_MARKS     0x00000020
#define FAN_ENABLE_AUDIT        0x00000040

/* Flags to determine fanotify event format */
#define FAN_REPORT_PIDFD        0x00000080      /* Report pidfd for event->pid */
#define FAN_REPORT_TID          0x00000100      /* event->pid is thread id */
#define FAN_REPORT_FID          0x00000200      /* Report unique file id */
#define FAN_REPORT_DIR_FID      0x00000400      /* Report unique directory id */
#define FAN_REPORT_NAME         0x00000800      /* Report events with name */
#define FAN_REPORT_TARGET_FID   0x00001000      /* Report dirent target id  */
#define FAN_REPORT_FD_ERROR     0x00002000      /* event->fd can report error */
#define FAN_REPORT_MNT          0x00004000      /* Report mount events */

/* Convenience macro - FAN_REPORT_NAME requires FAN_REPORT_DIR_FID */
#define FAN_REPORT_DFID_NAME    (FAN_REPORT_DIR_FID | FAN_REPORT_NAME)
/* Convenience macro - FAN_REPORT_TARGET_FID requires all other FID flags */
#define FAN_REPORT_DFID_NAME_TARGET (FAN_REPORT_DFID_NAME | \
                                     FAN_REPORT_FID | FAN_REPORT_TARGET_FID)

/* Deprecated - do not use this in programs and do not add new flags here! */
#define FAN_ALL_INIT_FLAGS      (FAN_CLOEXEC | FAN_NONBLOCK | \
                                 FAN_ALL_CLASS_BITS | FAN_UNLIMITED_QUEUE |\
                                 FAN_UNLIMITED_MARKS)

/* flags used for fanotify_modify_mark() */
#define FAN_MARK_ADD            0x00000001
#define FAN_MARK_REMOVE         0x00000002
#define FAN_MARK_DONT_FOLLOW    0x00000004
#define FAN_MARK_ONLYDIR        0x00000008
/* FAN_MARK_MOUNT is            0x00000010 */
#define FAN_MARK_IGNORED_MASK   0x00000020
#define FAN_MARK_IGNORED_SURV_MODIFY    0x00000040
#define FAN_MARK_FLUSH          0x00000080
/* FAN_MARK_FILESYSTEM is       0x00000100 */
#define FAN_MARK_EVICTABLE      0x00000200
/* This bit is mutually exclusive with FAN_MARK_IGNORED_MASK bit */
#define FAN_MARK_IGNORE         0x00000400

/* These are NOT bitwise flags.  Both bits can be used togther.  */
#define FAN_MARK_INODE          0x00000000
#define FAN_MARK_MOUNT          0x00000010
#define FAN_MARK_FILESYSTEM     0x00000100
#define FAN_MARK_MNTNS          0x00000110

/*
 * Convenience macro - FAN_MARK_IGNORE requires FAN_MARK_IGNORED_SURV_MODIFY
 * for non-inode mark types.
 */
#define FAN_MARK_IGNORE_SURV    (FAN_MARK_IGNORE | FAN_MARK_IGNORED_SURV_MODIFY)

/* Deprecated - do not use this in programs and do not add new flags here! */
#define FAN_ALL_MARK_FLAGS      (FAN_MARK_ADD |\
                                 FAN_MARK_REMOVE |\
                                 FAN_MARK_DONT_FOLLOW |\
                                 FAN_MARK_ONLYDIR |\
                                 FAN_MARK_MOUNT |\
                                 FAN_MARK_IGNORED_MASK |\
                                 FAN_MARK_IGNORED_SURV_MODIFY |\
                                 FAN_MARK_FLUSH)

/* Deprecated - do not use this in programs and do not add new flags here! */
#define FAN_ALL_EVENTS (FAN_ACCESS |\
                        FAN_MODIFY |\
                        FAN_CLOSE |\
                        FAN_OPEN)

/*
 * All events which require a permission response from userspace
 */
/* Deprecated - do not use this in programs and do not add new flags here! */
#define FAN_ALL_PERM_EVENTS (FAN_OPEN_PERM |\
                             FAN_ACCESS_PERM)

/* Deprecated - do not use this in programs and do not add new flags here! */
#define FAN_ALL_OUTGOING_EVENTS (FAN_ALL_EVENTS |\
                                 FAN_ALL_PERM_EVENTS |\
                                 FAN_Q_OVERFLOW)

#define FANOTIFY_METADATA_VERSION       3

struct fanotify_event_metadata {
        __u32 event_len;
        __u8 vers;
        __u8 reserved;
        __u16 metadata_len;
        __aligned_u64 mask;
        __s32 fd;
        __s32 pid;
};

#define FAN_EVENT_INFO_TYPE_FID         1
#define FAN_EVENT_INFO_TYPE_DFID_NAME   2
#define FAN_EVENT_INFO_TYPE_DFID        3
#define FAN_EVENT_INFO_TYPE_PIDFD       4
#define FAN_EVENT_INFO_TYPE_ERROR       5
#define FAN_EVENT_INFO_TYPE_RANGE       6
#define FAN_EVENT_INFO_TYPE_MNT         7

/* Special info types for FAN_RENAME */
#define FAN_EVENT_INFO_TYPE_OLD_DFID_NAME       10
/* Reserved for FAN_EVENT_INFO_TYPE_OLD_DFID    11 */
#define FAN_EVENT_INFO_TYPE_NEW_DFID_NAME       12
/* Reserved for FAN_EVENT_INFO_TYPE_NEW_DFID    13 */

/* Variable length info record following event metadata */
struct fanotify_event_info_header {
        __u8 info_type;
        __u8 pad;
        __u16 len;
};

/*
 * Unique file identifier info record.
 * This structure is used for records of types FAN_EVENT_INFO_TYPE_FID,
 * FAN_EVENT_INFO_TYPE_DFID and FAN_EVENT_INFO_TYPE_DFID_NAME.
 * For FAN_EVENT_INFO_TYPE_DFID_NAME there is additionally a null terminated
 * name immediately after the file handle.
 */
struct fanotify_event_info_fid {
        struct fanotify_event_info_header hdr;
        __kernel_fsid_t fsid;
        /*
         * Following is an opaque struct file_handle that can be passed as
         * an argument to open_by_handle_at(2).
         */
        unsigned char handle[];
};

/*
 * This structure is used for info records of type FAN_EVENT_INFO_TYPE_PIDFD.
 * It holds a pidfd for the pid that was responsible for generating an event.
 */
struct fanotify_event_info_pidfd {
        struct fanotify_event_info_header hdr;
        __s32 pidfd;
};

struct fanotify_event_info_error {
        struct fanotify_event_info_header hdr;
        __s32 error;
        __u32 error_count;
};

struct fanotify_event_info_range {
        struct fanotify_event_info_header hdr;
        __u32 pad;
        __u64 offset;
        __u64 count;
};

struct fanotify_event_info_mnt {
        struct fanotify_event_info_header hdr;
        __u64 mnt_id;
};

/*
 * User space may need to record additional information about its decision.
 * The extra information type records what kind of information is included.
 * The default is none. We also define an extra information buffer whose
 * size is determined by the extra information type.
 *
 * If the information type is Audit Rule, then the information following
 * is the rule number that triggered the user space decision that
 * requires auditing.
 */

#define FAN_RESPONSE_INFO_NONE          0
#define FAN_RESPONSE_INFO_AUDIT_RULE    1

struct fanotify_response {
        __s32 fd;
        __u32 response;
};

struct fanotify_response_info_header {
        __u8 type;
        __u8 pad;
        __u16 len;
};

struct fanotify_response_info_audit_rule {
        struct fanotify_response_info_header hdr;
        __u32 rule_number;
        __u32 subj_trust;
        __u32 obj_trust;
};

/* Legit userspace responses to a _PERM event */
#define FAN_ALLOW       0x01
#define FAN_DENY        0x02
/* errno other than EPERM can specified in upper byte of deny response */
#define FAN_ERRNO_BITS  8
#define FAN_ERRNO_SHIFT (32 - FAN_ERRNO_BITS)
#define FAN_ERRNO_MASK  ((1 << FAN_ERRNO_BITS) - 1)
#define FAN_DENY_ERRNO(err) \
        (FAN_DENY | ((((__u32)(err)) & FAN_ERRNO_MASK) << FAN_ERRNO_SHIFT))

#define FAN_AUDIT       0x10    /* Bitmask to create audit record for result */
#define FAN_INFO        0x20    /* Bitmask to indicate additional information */

/* No fd set in event */
#define FAN_NOFD        -1
#define FAN_NOPIDFD     FAN_NOFD
#define FAN_EPIDFD      -2

/* Helper functions to deal with fanotify_event_metadata buffers */
#define FAN_EVENT_METADATA_LEN (sizeof(struct fanotify_event_metadata))

#define FAN_EVENT_NEXT(meta, len) ((len) -= (meta)->event_len, \
                                   (struct fanotify_event_metadata*)(((char *)(meta)) + \
                                   (meta)->event_len))

#define FAN_EVENT_OK(meta, len) ((long)(len) >= (long)FAN_EVENT_METADATA_LEN && \
                                (long)(meta)->event_len >= (long)FAN_EVENT_METADATA_LEN && \
                                (long)(meta)->event_len <= (long)(len))

#endif /* _UAPI_LINUX_FANOTIFY_H */