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).
Showing the changes to include/uapi/linux (1 of 1 file). Show all
Unified · Split
| @@ -0,0 +1,55 @@ | ||
| 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 */ | |