diff options
Diffstat (limited to 'samples')
| -rw-r--r-- | samples/Kconfig | 7 | ||||
| -rw-r--r-- | samples/Makefile | 1 | ||||
| -rw-r--r-- | samples/watch_queue/Makefile | 7 | ||||
| -rw-r--r-- | samples/watch_queue/watch_test.c | 186 |
4 files changed, 201 insertions, 0 deletions
diff --git a/samples/Kconfig b/samples/Kconfig index 0cbb6146f3cf..add431173bcc 100644 --- a/samples/Kconfig +++ b/samples/Kconfig @@ -209,4 +209,11 @@ config SAMPLE_WATCHDOG bool "watchdog sample" depends on CC_CAN_LINK +config SAMPLE_WATCH_QUEUE + bool "Build example /dev/watch_queue notification consumer" + depends on HEADERS_INSTALL + help + Build example userspace program to use the new mount_notify(), + sb_notify() syscalls and the KEYCTL_WATCH_KEY keyctl() function. + endif # SAMPLES diff --git a/samples/Makefile b/samples/Makefile index 29c66aadd954..5b2629778754 100644 --- a/samples/Makefile +++ b/samples/Makefile @@ -27,3 +27,4 @@ obj-y += vfio-mdev/ subdir-$(CONFIG_SAMPLE_VFS) += vfs obj-$(CONFIG_SAMPLE_INTEL_MEI) += mei/ subdir-$(CONFIG_SAMPLE_WATCHDOG) += watchdog +subdir-$(CONFIG_SAMPLE_WATCH_QUEUE) += watch_queue diff --git a/samples/watch_queue/Makefile b/samples/watch_queue/Makefile new file mode 100644 index 000000000000..8511fb6c53d2 --- /dev/null +++ b/samples/watch_queue/Makefile @@ -0,0 +1,7 @@ +# List of programs to build +hostprogs := watch_test + +# Tell kbuild to always build the programs +always-y := $(hostprogs) + +HOSTCFLAGS_watch_test.o += -I$(objtree)/usr/include diff --git a/samples/watch_queue/watch_test.c b/samples/watch_queue/watch_test.c new file mode 100644 index 000000000000..46e618a897fe --- /dev/null +++ b/samples/watch_queue/watch_test.c @@ -0,0 +1,186 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Use /dev/watch_queue 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); +} |