summaryrefslogtreecommitdiff
path: root/samples/watch_queue/watch_test.c
blob: 8c6cb57d5cfc5b3b79e803a51a860a80af4b4a51 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
// SPDX-License-Identifier: GPL-2.0
/* Use watch_queue API to watch for notifications.
 *
 * Copyright (C) 2020 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */

#define _GNU_SOURCE
#include <stdbool.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <unistd.h>
#include <errno.h>
#include <sys/ioctl.h>
#include <limits.h>
#include <linux/watch_queue.h>
#include <linux/unistd.h>
#include <linux/keyctl.h>

#ifndef KEYCTL_WATCH_KEY
#define KEYCTL_WATCH_KEY -1
#endif
#ifndef __NR_keyctl
#define __NR_keyctl -1
#endif

#define BUF_SIZE 256

static long keyctl_watch_key(int key, int watch_fd, int watch_id)
{
	return syscall(__NR_keyctl, KEYCTL_WATCH_KEY, key, watch_fd, watch_id);
}

static const char *key_subtypes[256] = {
	[NOTIFY_KEY_INSTANTIATED]	= "instantiated",
	[NOTIFY_KEY_UPDATED]		= "updated",
	[NOTIFY_KEY_LINKED]		= "linked",
	[NOTIFY_KEY_UNLINKED]		= "unlinked",
	[NOTIFY_KEY_CLEARED]		= "cleared",
	[NOTIFY_KEY_REVOKED]		= "revoked",
	[NOTIFY_KEY_INVALIDATED]	= "invalidated",
	[NOTIFY_KEY_SETATTR]		= "setattr",
};

static void saw_key_change(struct watch_notification *n, size_t len)
{
	struct key_notification *k = (struct key_notification *)n;

	if (len != sizeof(struct key_notification)) {
		fprintf(stderr, "Incorrect key message length\n");
		return;
	}

	printf("KEY %08x change=%u[%s] aux=%u\n",
	       k->key_id, n->subtype, key_subtypes[n->subtype], k->aux);
}

/*
 * Consume and display events.
 */
static void consumer(int fd)
{
	unsigned char buffer[433], *p, *end;
	union {
		struct watch_notification n;
		unsigned char buf1[128];
	} n;
	ssize_t buf_len;

	for (;;) {
		buf_len = read(fd, buffer, sizeof(buffer));
		if (buf_len == -1) {
			perror("read");
			exit(1);
		}

		if (buf_len == 0) {
			printf("-- END --\n");
			return;
		}

		if (buf_len > sizeof(buffer)) {
			fprintf(stderr, "Read buffer overrun: %zd\n", buf_len);
			return;
		}

		printf("read() = %zd\n", buf_len);

		p = buffer;
		end = buffer + buf_len;
		while (p < end) {
			size_t largest, len;

			largest = end - p;
			if (largest > 128)
				largest = 128;
			if (largest < sizeof(struct watch_notification)) {
				fprintf(stderr, "Short message header: %zu\n", largest);
				return;
			}
			memcpy(&n, p, largest);

			printf("NOTIFY[%03zx]: ty=%06x sy=%02x i=%08x\n",
			       p - buffer, n.n.type, n.n.subtype, n.n.info);

			len = n.n.info & WATCH_INFO_LENGTH;
			if (len < sizeof(n.n) || len > largest) {
				fprintf(stderr, "Bad message length: %zu/%zu\n", len, largest);
				exit(1);
			}

			switch (n.n.type) {
			case WATCH_TYPE_META:
				switch (n.n.subtype) {
				case WATCH_META_REMOVAL_NOTIFICATION:
					printf("REMOVAL of watchpoint %08x\n",
					       (n.n.info & WATCH_INFO_ID) >>
					       WATCH_INFO_ID__SHIFT);
					break;
				case WATCH_META_LOSS_NOTIFICATION:
					printf("-- LOSS --\n");
					break;
				default:
					printf("other meta record\n");
					break;
				}
				break;
			case WATCH_TYPE_KEY_NOTIFY:
				saw_key_change(&n.n, len);
				break;
			default:
				printf("other type\n");
				break;
			}

			p += len;
		}
	}
}

static struct watch_notification_filter filter = {
	.nr_filters	= 1,
	.filters = {
		[0]	= {
			.type			= WATCH_TYPE_KEY_NOTIFY,
			.subtype_filter[0]	= UINT_MAX,
		},
	},
};

int main(int argc, char **argv)
{
	int pipefd[2], fd;

	if (pipe2(pipefd, O_NOTIFICATION_PIPE) == -1) {
		perror("pipe2");
		exit(1);
	}
	fd = pipefd[0];

	if (ioctl(fd, IOC_WATCH_QUEUE_SET_SIZE, BUF_SIZE) == -1) {
		perror("watch_queue(size)");
		exit(1);
	}

	if (ioctl(fd, IOC_WATCH_QUEUE_SET_FILTER, &filter) == -1) {
		perror("watch_queue(filter)");
		exit(1);
	}

	if (keyctl_watch_key(KEY_SPEC_SESSION_KEYRING, fd, 0x01) == -1) {
		perror("keyctl");
		exit(1);
	}

	if (keyctl_watch_key(KEY_SPEC_USER_KEYRING, fd, 0x02) == -1) {
		perror("keyctl");
		exit(1);
	}

	consumer(fd);
	exit(0);
}