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Diffstat (limited to 'src/libudev/libudev-queue.c')
| -rw-r--r-- | src/libudev/libudev-queue.c | 236 |
1 files changed, 236 insertions, 0 deletions
diff --git a/src/libudev/libudev-queue.c b/src/libudev/libudev-queue.c new file mode 100644 index 0000000..4e055bb --- /dev/null +++ b/src/libudev/libudev-queue.c @@ -0,0 +1,236 @@ +/* SPDX-License-Identifier: LGPL-2.1+ */ +/*** + Copyright © 2009 Alan Jenkins <alan-jenkins@tuffmail.co.uk> +***/ + +#include <errno.h> +#include <stddef.h> +#include <stdlib.h> +#include <sys/inotify.h> +#include <unistd.h> + +#include "libudev.h" + +#include "alloc-util.h" +#include "fd-util.h" +#include "io-util.h" + +/** + * SECTION:libudev-queue + * @short_description: access to currently active events + * + * This exports the current state of the udev processing queue. + */ + +/** + * udev_queue: + * + * Opaque object representing the current event queue in the udev daemon. + */ +struct udev_queue { + struct udev *udev; + unsigned n_ref; + int fd; +}; + +/** + * udev_queue_new: + * @udev: udev library context + * + * The initial refcount is 1, and needs to be decremented to + * release the resources of the udev queue context. + * + * Returns: the udev queue context, or #NULL on error. + **/ +_public_ struct udev_queue *udev_queue_new(struct udev *udev) { + struct udev_queue *udev_queue; + + udev_queue = new(struct udev_queue, 1); + if (!udev_queue) + return_with_errno(NULL, ENOMEM); + + *udev_queue = (struct udev_queue) { + .udev = udev, + .n_ref = 1, + .fd = -1, + }; + + return udev_queue; +} + +static struct udev_queue *udev_queue_free(struct udev_queue *udev_queue) { + assert(udev_queue); + + safe_close(udev_queue->fd); + return mfree(udev_queue); +} + +/** + * udev_queue_ref: + * @udev_queue: udev queue context + * + * Take a reference of a udev queue context. + * + * Returns: the same udev queue context. + **/ + +/** + * udev_queue_unref: + * @udev_queue: udev queue context + * + * Drop a reference of a udev queue context. If the refcount reaches zero, + * the resources of the queue context will be released. + * + * Returns: #NULL + **/ +DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(struct udev_queue, udev_queue, udev_queue_free); + +/** + * udev_queue_get_udev: + * @udev_queue: udev queue context + * + * Retrieve the udev library context the queue context was created with. + * + * Returns: the udev library context. + **/ +_public_ struct udev *udev_queue_get_udev(struct udev_queue *udev_queue) { + assert_return_errno(udev_queue, NULL, EINVAL); + + return udev_queue->udev; +} + +/** + * udev_queue_get_kernel_seqnum: + * @udev_queue: udev queue context + * + * This function is deprecated. + * + * Returns: 0. + **/ +_public_ unsigned long long int udev_queue_get_kernel_seqnum(struct udev_queue *udev_queue) { + return 0; +} + +/** + * udev_queue_get_udev_seqnum: + * @udev_queue: udev queue context + * + * This function is deprecated. + * + * Returns: 0. + **/ +_public_ unsigned long long int udev_queue_get_udev_seqnum(struct udev_queue *udev_queue) { + return 0; +} + +/** + * udev_queue_get_udev_is_active: + * @udev_queue: udev queue context + * + * Check if udev is active on the system. + * + * Returns: a flag indicating if udev is active. + **/ +_public_ int udev_queue_get_udev_is_active(struct udev_queue *udev_queue) { + return access("/run/udev/control", F_OK) >= 0; +} + +/** + * udev_queue_get_queue_is_empty: + * @udev_queue: udev queue context + * + * Check if udev is currently processing any events. + * + * Returns: a flag indicating if udev is currently handling events. + **/ +_public_ int udev_queue_get_queue_is_empty(struct udev_queue *udev_queue) { + return access("/run/udev/queue", F_OK) < 0; +} + +/** + * udev_queue_get_seqnum_sequence_is_finished: + * @udev_queue: udev queue context + * @start: first event sequence number + * @end: last event sequence number + * + * This function is deprecated, it just returns the result of + * udev_queue_get_queue_is_empty(). + * + * Returns: a flag indicating if udev is currently handling events. + **/ +_public_ int udev_queue_get_seqnum_sequence_is_finished(struct udev_queue *udev_queue, + unsigned long long int start, unsigned long long int end) { + return udev_queue_get_queue_is_empty(udev_queue); +} + +/** + * udev_queue_get_seqnum_is_finished: + * @udev_queue: udev queue context + * @seqnum: sequence number + * + * This function is deprecated, it just returns the result of + * udev_queue_get_queue_is_empty(). + * + * Returns: a flag indicating if udev is currently handling events. + **/ +_public_ int udev_queue_get_seqnum_is_finished(struct udev_queue *udev_queue, unsigned long long int seqnum) { + return udev_queue_get_queue_is_empty(udev_queue); +} + +/** + * udev_queue_get_queued_list_entry: + * @udev_queue: udev queue context + * + * This function is deprecated. + * + * Returns: NULL. + **/ +_public_ struct udev_list_entry *udev_queue_get_queued_list_entry(struct udev_queue *udev_queue) { + return_with_errno(NULL, ENODATA); +} + +/** + * udev_queue_get_fd: + * @udev_queue: udev queue context + * + * Returns: a file descriptor to watch for a queue to become empty. + */ +_public_ int udev_queue_get_fd(struct udev_queue *udev_queue) { + _cleanup_close_ int fd = -1; + + assert_return(udev_queue, -EINVAL); + + if (udev_queue->fd >= 0) + return udev_queue->fd; + + fd = inotify_init1(IN_CLOEXEC); + if (fd < 0) + return -errno; + + if (inotify_add_watch(fd, "/run/udev" , IN_DELETE) < 0) + return -errno; + + udev_queue->fd = TAKE_FD(fd); + return udev_queue->fd; +} + +/** + * udev_queue_flush: + * @udev_queue: udev queue context + * + * Returns: the result of clearing the watch for queue changes. + */ +_public_ int udev_queue_flush(struct udev_queue *udev_queue) { + int r; + + assert_return(udev_queue, -EINVAL); + + if (udev_queue->fd < 0) + return -EINVAL; + + r = flush_fd(udev_queue->fd); + if (r < 0) + return r; + + return 0; +} |