Add UAPI definitions for the general notification queue, including the following pieces: (*) struct watch_notification. This is the metadata header for notification messages. It includes a type and subtype that indicate the source of the message (eg. WATCH_TYPE_MOUNT_NOTIFY) and the kind of the message (eg. NOTIFY_MOUNT_NEW_MOUNT). The header also contains an information field that conveys the following information: - WATCH_INFO_LENGTH. The size of the entry (entries are variable length). - WATCH_INFO_ID. The watch ID specified when the watchpoint was set. - WATCH_INFO_TYPE_INFO. (Sub)type-specific information. - WATCH_INFO_FLAG_*. Flag bits overlain on the type-specific information. For use by the type. All the information in the header can be used in filtering messages at the point of writing into the buffer. (*) struct watch_notification_removal This is an extended watch-removal notification record that includes an 'id' field that can indicate the identifier of the object being removed if available (for instance, a keyring serial number).
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| 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 | |||
| 7 | enum watch_notification_type { | ||
| 8 | WATCH_TYPE_META = 0, /* Special record */ | ||
| 9 | WATCH_TYPE__NR = 1 | ||
| 10 | }; | ||
| 11 | |||
| 12 | enum watch_meta_notification_subtype { | ||
| 13 | WATCH_META_REMOVAL_NOTIFICATION = 0, /* Watched object was removed */ | ||
| 14 | WATCH_META_LOSS_NOTIFICATION = 1, /* Data loss occurred */ | ||
| 15 | }; | ||
| 16 | |||
| 17 | /* | ||
| 18 | * Notification record header. This is aligned to 64-bits so that subclasses | ||
| 19 | * can contain __u64 fields. | ||
| 20 | */ | ||
| 21 | struct watch_notification { | ||
| 22 | __u32 type:24; /* enum watch_notification_type */ | ||
| 23 | __u32 subtype:8; /* Type-specific subtype (filterable) */ | ||
| 24 | __u32 info; | ||
| 25 | #define WATCH_INFO_LENGTH 0x0000007f /* Length of record */ | ||
| 26 | #define WATCH_INFO_LENGTH__SHIFT 0 | ||
| 27 | #define WATCH_INFO_ID 0x0000ff00 /* ID of watchpoint */ | ||
| 28 | #define WATCH_INFO_ID__SHIFT 8 | ||
| 29 | #define WATCH_INFO_TYPE_INFO 0xffff0000 /* Type-specific info */ | ||
| 30 | #define WATCH_INFO_TYPE_INFO__SHIFT 16 | ||
| 31 | #define WATCH_INFO_FLAG_0 0x00010000 /* Type-specific info, flag bit 0 */ | ||
| 32 | #define WATCH_INFO_FLAG_1 0x00020000 /* ... */ | ||
| 33 | #define WATCH_INFO_FLAG_2 0x00040000 | ||
| 34 | #define WATCH_INFO_FLAG_3 0x00080000 | ||
| 35 | #define WATCH_INFO_FLAG_4 0x00100000 | ||
| 36 | #define WATCH_INFO_FLAG_5 0x00200000 | ||
| 37 | #define WATCH_INFO_FLAG_6 0x00400000 | ||
| 38 | #define WATCH_INFO_FLAG_7 0x00800000 | ||
| 39 | }; | ||
| 40 | |||
| 41 | |||
| 42 | /* | ||
| 43 | * Extended watch removal notification. This is used optionally if the type | ||
| 44 | * wants to indicate an identifier for the object being watched, if there is | ||
| 45 | * such. This can be distinguished by the length. | ||
| 46 | * | ||
| 47 | * type -> WATCH_TYPE_META | ||
| 48 | * subtype -> WATCH_META_REMOVAL_NOTIFICATION | ||
| 49 | */ | ||
| 50 | struct watch_notification_removal { | ||
| 51 | struct watch_notification watch; | ||
| 52 | __u64 id; /* Type-dependent identifier */ | ||
| 53 | }; | ||
| 54 | |||
| 55 | #endif /* _UAPI_LINUX_WATCH_QUEUE_H */ | ||