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-rw-r--r--samples/watch_queue/.gitignore1
-rw-r--r--samples/watch_queue/Makefile4
-rw-r--r--samples/watch_queue/watch_test.c186
3 files changed, 191 insertions, 0 deletions
diff --git a/samples/watch_queue/.gitignore b/samples/watch_queue/.gitignore
new file mode 100644
index 000000000..2aa3c7e56
--- /dev/null
+++ b/samples/watch_queue/.gitignore
@@ -0,0 +1 @@
+watch_test
diff --git a/samples/watch_queue/Makefile b/samples/watch_queue/Makefile
new file mode 100644
index 000000000..c0db3a6bc
--- /dev/null
+++ b/samples/watch_queue/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
+userprogs-always-y += watch_test
+
+userccflags += -I usr/include
diff --git a/samples/watch_queue/watch_test.c b/samples/watch_queue/watch_test.c
new file mode 100644
index 000000000..8c6cb57d5
--- /dev/null
+++ b/samples/watch_queue/watch_test.c
@@ -0,0 +1,186 @@
+// 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);
+}