diff options
Diffstat (limited to 'src/libsystemd/sd-event/event-source.h')
| -rw-r--r-- | src/libsystemd/sd-event/event-source.h | 206 |
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); +}; |