summaryrefslogtreecommitdiffstats
path: root/src/libsystemd/sd-event/event-source.h
diff options
context:
space:
mode:
Diffstat (limited to 'src/libsystemd/sd-event/event-source.h')
-rw-r--r--src/libsystemd/sd-event/event-source.h206
1 files changed, 206 insertions, 0 deletions
diff --git a/src/libsystemd/sd-event/event-source.h b/src/libsystemd/sd-event/event-source.h
new file mode 100644
index 0000000..99ab8fc
--- /dev/null
+++ b/src/libsystemd/sd-event/event-source.h
@@ -0,0 +1,206 @@
+#pragma once
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include <sys/epoll.h>
+#include <sys/timerfd.h>
+#include <sys/wait.h>
+
+#include "sd-event.h"
+
+#include "fs-util.h"
+#include "hashmap.h"
+#include "list.h"
+#include "prioq.h"
+
+typedef enum EventSourceType {
+ SOURCE_IO,
+ SOURCE_TIME_REALTIME,
+ SOURCE_TIME_BOOTTIME,
+ SOURCE_TIME_MONOTONIC,
+ SOURCE_TIME_REALTIME_ALARM,
+ SOURCE_TIME_BOOTTIME_ALARM,
+ SOURCE_SIGNAL,
+ SOURCE_CHILD,
+ SOURCE_DEFER,
+ SOURCE_POST,
+ SOURCE_EXIT,
+ SOURCE_WATCHDOG,
+ SOURCE_INOTIFY,
+ _SOURCE_EVENT_SOURCE_TYPE_MAX,
+ _SOURCE_EVENT_SOURCE_TYPE_INVALID = -1
+} EventSourceType;
+
+/* All objects we use in epoll events start with this value, so that
+ * we know how to dispatch it */
+typedef enum WakeupType {
+ WAKEUP_NONE,
+ WAKEUP_EVENT_SOURCE,
+ WAKEUP_CLOCK_DATA,
+ WAKEUP_SIGNAL_DATA,
+ WAKEUP_INOTIFY_DATA,
+ _WAKEUP_TYPE_MAX,
+ _WAKEUP_TYPE_INVALID = -1,
+} WakeupType;
+
+struct inode_data;
+
+struct sd_event_source {
+ WakeupType wakeup;
+
+ unsigned n_ref;
+
+ sd_event *event;
+ void *userdata;
+ sd_event_handler_t prepare;
+
+ char *description;
+
+ EventSourceType type:5;
+ signed int enabled:3;
+ bool pending:1;
+ bool dispatching:1;
+ bool floating:1;
+
+ int64_t priority;
+ unsigned pending_index;
+ unsigned prepare_index;
+ uint64_t pending_iteration;
+ uint64_t prepare_iteration;
+
+ sd_event_destroy_t destroy_callback;
+
+ LIST_FIELDS(sd_event_source, sources);
+
+ union {
+ struct {
+ sd_event_io_handler_t callback;
+ int fd;
+ uint32_t events;
+ uint32_t revents;
+ bool registered:1;
+ bool owned:1;
+ } io;
+ struct {
+ sd_event_time_handler_t callback;
+ usec_t next, accuracy;
+ unsigned earliest_index;
+ unsigned latest_index;
+ } time;
+ struct {
+ sd_event_signal_handler_t callback;
+ struct signalfd_siginfo siginfo;
+ int sig;
+ } signal;
+ struct {
+ sd_event_child_handler_t callback;
+ siginfo_t siginfo;
+ pid_t pid;
+ int options;
+ } child;
+ struct {
+ sd_event_handler_t callback;
+ } defer;
+ struct {
+ sd_event_handler_t callback;
+ } post;
+ struct {
+ sd_event_handler_t callback;
+ unsigned prioq_index;
+ } exit;
+ struct {
+ sd_event_inotify_handler_t callback;
+ uint32_t mask;
+ struct inode_data *inode_data;
+ LIST_FIELDS(sd_event_source, by_inode_data);
+ } inotify;
+ };
+};
+
+struct clock_data {
+ WakeupType wakeup;
+ int fd;
+
+ /* For all clocks we maintain two priority queues each, one
+ * ordered for the earliest times the events may be
+ * dispatched, and one ordered by the latest times they must
+ * have been dispatched. The range between the top entries in
+ * the two prioqs is the time window we can freely schedule
+ * wakeups in */
+
+ Prioq *earliest;
+ Prioq *latest;
+ usec_t next;
+
+ bool needs_rearm:1;
+};
+
+struct signal_data {
+ WakeupType wakeup;
+
+ /* For each priority we maintain one signal fd, so that we
+ * only have to dequeue a single event per priority at a
+ * time. */
+
+ int fd;
+ int64_t priority;
+ sigset_t sigset;
+ sd_event_source *current;
+};
+
+/* A structure listing all event sources currently watching a specific inode */
+struct inode_data {
+ /* The identifier for the inode, the combination of the .st_dev + .st_ino fields of the file */
+ ino_t ino;
+ dev_t dev;
+
+ /* An fd of the inode to watch. The fd is kept open until the next iteration of the loop, so that we can
+ * rearrange the priority still until then, as we need the original inode to change the priority as we need to
+ * add a watch descriptor to the right inotify for the priority which we can only do if we have a handle to the
+ * original inode. We keep a list of all inode_data objects with an open fd in the to_close list (see below) of
+ * the sd-event object, so that it is efficient to close everything, before entering the next event loop
+ * iteration. */
+ int fd;
+
+ /* The inotify "watch descriptor" */
+ int wd;
+
+ /* The combination of the mask of all inotify watches on this inode we manage. This is also the mask that has
+ * most recently been set on the watch descriptor. */
+ uint32_t combined_mask;
+
+ /* All event sources subscribed to this inode */
+ LIST_HEAD(sd_event_source, event_sources);
+
+ /* The inotify object we watch this inode with */
+ struct inotify_data *inotify_data;
+
+ /* A linked list of all inode data objects with fds to close (see above) */
+ LIST_FIELDS(struct inode_data, to_close);
+};
+
+/* A structure encapsulating an inotify fd */
+struct inotify_data {
+ WakeupType wakeup;
+
+ /* For each priority we maintain one inotify fd, so that we only have to dequeue a single event per priority at
+ * a time */
+
+ int fd;
+ int64_t priority;
+
+ Hashmap *inodes; /* The inode_data structures keyed by dev+ino */
+ Hashmap *wd; /* The inode_data structures keyed by the watch descriptor for each */
+
+ /* The buffer we read inotify events into */
+ union inotify_event_buffer buffer;
+ size_t buffer_filled; /* fill level of the buffer */
+
+ /* How many event sources are currently marked pending for this inotify. We won't read new events off the
+ * inotify fd as long as there are still pending events on the inotify (because we have no strategy of queuing
+ * the events locally if they can't be coalesced). */
+ unsigned n_pending;
+
+ /* A linked list of all inotify objects with data already read, that still need processing. We keep this list
+ * to make it efficient to figure out what inotify objects to process data on next. */
+ LIST_FIELDS(struct inotify_data, buffered);
+};