include/uapi/linux/watch_queue.h

   1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
   2 #ifndef _UAPI_LINUX_WATCH_QUEUE_H
   3 #define _UAPI_LINUX_WATCH_QUEUE_H
   4
   5 #include <linux/types.h>
   6 #include <linux/fcntl.h>
   7 #include <linux/ioctl.h>
   8
   9 #define O_NOTIFICATION_PIPE     O_EXCL  /* Parameter to pipe2() selecting notification pipe */
  10
  11 #define IOC_WATCH_QUEUE_SET_SIZE        _IO('W', 0x60)  /* Set the size in pages */
  12 #define IOC_WATCH_QUEUE_SET_FILTER      _IO('W', 0x61)  /* Set the filter */
  13
  14 enum watch_notification_type {
  15         WATCH_TYPE_META         = 0,    /* Special record */
  16         WATCH_TYPE_KEY_NOTIFY   = 1,    /* Key change event notification */
  17         WATCH_TYPE__NR          = 2
  18 };
  19
  20 enum watch_meta_notification_subtype {
  21         WATCH_META_REMOVAL_NOTIFICATION = 0,    /* Watched object was removed */
  22         WATCH_META_LOSS_NOTIFICATION    = 1,    /* Data loss occurred */
  23 };
  24
  25 /*
  26  * Notification record header.  This is aligned to 64-bits so that subclasses
  27  * can contain __u64 fields.
  28  */
  29 struct watch_notification {
  30         __u32                   type:24;        /* enum watch_notification_type */
  31         __u32                   subtype:8;      /* Type-specific subtype (filterable) */
  32         __u32                   info;
  33 #define WATCH_INFO_LENGTH       0x0000007f      /* Length of record */
  34 #define WATCH_INFO_LENGTH__SHIFT 0
  35 #define WATCH_INFO_ID           0x0000ff00      /* ID of watchpoint */
  36 #define WATCH_INFO_ID__SHIFT    8
  37 #define WATCH_INFO_TYPE_INFO    0xffff0000      /* Type-specific info */
  38 #define WATCH_INFO_TYPE_INFO__SHIFT 16
  39 #define WATCH_INFO_FLAG_0       0x00010000      /* Type-specific info, flag bit 0 */
  40 #define WATCH_INFO_FLAG_1       0x00020000      /* ... */
  41 #define WATCH_INFO_FLAG_2       0x00040000
  42 #define WATCH_INFO_FLAG_3       0x00080000
  43 #define WATCH_INFO_FLAG_4       0x00100000
  44 #define WATCH_INFO_FLAG_5       0x00200000
  45 #define WATCH_INFO_FLAG_6       0x00400000
  46 #define WATCH_INFO_FLAG_7       0x00800000
  47 };
  48
  49 /*
  50  * Notification filtering rules (IOC_WATCH_QUEUE_SET_FILTER).
  51  */
  52 struct watch_notification_type_filter {
  53         __u32   type;                   /* Type to apply filter to */
  54         __u32   info_filter;            /* Filter on watch_notification::info */
  55         __u32   info_mask;              /* Mask of relevant bits in info_filter */
  56         __u32   subtype_filter[8];      /* Bitmask of subtypes to filter on */
  57 };
  58
  59 struct watch_notification_filter {
  60         __u32   nr_filters;             /* Number of filters */
  61         __u32   __reserved;             /* Must be 0 */
  62         struct watch_notification_type_filter filters[];
  63 };
  64
  65
  66 /*
  67  * Extended watch removal notification.  This is used optionally if the type
  68  * wants to indicate an identifier for the object being watched, if there is
  69  * such.  This can be distinguished by the length.
  70  *
  71  * type -> WATCH_TYPE_META
  72  * subtype -> WATCH_META_REMOVAL_NOTIFICATION
  73  */
  74 struct watch_notification_removal {
  75         struct watch_notification watch;
  76         __u64   id;             /* Type-dependent identifier */
  77 };
  78
  79 /*
  80  * Type of key/keyring change notification.
  81  */
  82 enum key_notification_subtype {
  83         NOTIFY_KEY_INSTANTIATED = 0, /* Key was instantiated (aux is error code) */
  84         NOTIFY_KEY_UPDATED      = 1, /* Key was updated */
  85         NOTIFY_KEY_LINKED       = 2, /* Key (aux) was added to watched keyring */
  86         NOTIFY_KEY_UNLINKED     = 3, /* Key (aux) was removed from watched keyring */
  87         NOTIFY_KEY_CLEARED      = 4, /* Keyring was cleared */
  88         NOTIFY_KEY_REVOKED      = 5, /* Key was revoked */
  89         NOTIFY_KEY_INVALIDATED  = 6, /* Key was invalidated */
  90         NOTIFY_KEY_SETATTR      = 7, /* Key's attributes got changed */
  91 };
  92
  93 /*
  94  * Key/keyring notification record.
  95  * - watch.type = WATCH_TYPE_KEY_NOTIFY
  96  * - watch.subtype = enum key_notification_type
  97  */
  98 struct key_notification {
  99         struct watch_notification watch;
 100         __u32   key_id;         /* The key/keyring affected */
 101         __u32   aux;            /* Per-type auxiliary data */
 102 };
 103
 104 #endif /* _UAPI_LINUX_WATCH_QUEUE_H */