fanotify.h

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#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_CLOSE_WRITE     0x00000008  /* Writtable file closed */
#define FAN_CLOSE_NOWRITE   0x00000010  /* Unwrittable file closed */
#define FAN_OPEN        0x00000020  /* File was opened */

#define FAN_Q_OVERFLOW      0x00004000  /* Event queued overflowed */

#define FAN_OPEN_PERM       0x00010000  /* File open in perm check */
#define FAN_ACCESS_PERM     0x00020000  /* File accessed in perm check */

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

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

/* helper events */
#define FAN_CLOSE       (FAN_CLOSE_WRITE | FAN_CLOSE_NOWRITE) /* close */

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

/* These are NOT bitwise flags.  Both bits are used togther.  */
#define FAN_CLASS_NOTIF     0x00000000
#define FAN_CLASS_CONTENT   0x00000004
#define FAN_CLASS_PRE_CONTENT   0x00000008
#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_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
#define FAN_MARK_MOUNT      0x00000010
#define FAN_MARK_IGNORED_MASK   0x00000020
#define FAN_MARK_IGNORED_SURV_MODIFY    0x00000040
#define FAN_MARK_FLUSH      0x00000080

#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)

/*
 * All of the events - we build the list by hand so that we can add flags in
 * the future and not break backward compatibility.  Apps will get only the
 * events that they originally wanted.  Be sure to add new events here!
 */
#define FAN_ALL_EVENTS (FAN_ACCESS |\
            FAN_MODIFY |\
            FAN_CLOSE |\
            FAN_OPEN)

/*
 * All events which require a permission response from userspace
 */
#define FAN_ALL_PERM_EVENTS (FAN_OPEN_PERM |\
                 FAN_ACCESS_PERM)

#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;
};

struct fanotify_response {
    __s32 fd;
    __u32 response;
};

/* Legit userspace responses to a _PERM event */
#define FAN_ALLOW   0x01
#define FAN_DENY    0x02
/* No fd set in event */
#define FAN_NOFD    -1

/* 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 */