/* Definitions used by the GDB event loop.
- Copyright (C) 1999, 2000, 2007, 2008 Free Software Foundation, Inc.
+ Copyright (C) 1999-2020 Free Software Foundation, Inc.
Written by Elena Zannoni <ezannoni@cygnus.com> of Cygnus Solutions.
This file is part of GDB.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
-/* An event loop listens for events from multiple event sources. When
+#ifndef EVENT_LOOP_H
+#define EVENT_LOOP_H
+
+/* An event loop listens for events from multiple event sources. When
an event arrives, it is queued and processed by calling the
- appropriate event handler. The event loop then continues to listen
- for more events. An event loop completes when there are no event
+ appropriate event handler. The event loop then continues to listen
+ for more events. An event loop completes when there are no event
sources to listen on. External event sources can be plugged into
the loop.
- There are 3 main components:
- - a list of file descriptors to be monitored, GDB_NOTIFIER.
- - a list of events that have occurred, EVENT_QUEUE.
+ There are 4 main components:
+ - a list of file descriptors to be monitored, GDB_NOTIFIER.
+ - a list of asynchronous event sources to be monitored,
+ ASYNC_EVENT_HANDLER_LIST.
+ - a list of events that have occurred, EVENT_QUEUE.
- a list of signal handling functions, SIGHANDLER_LIST.
- GDB_NOTIFIER keeps track of the event sources. Event sources for
- gdb are currently the UI and the target. Gdb communicates with the
- command line user interface via the readline library and usually
- communicates with remote targets via a serial port. Serial ports
- are represented in GDB as file descriptors and select/poll calls.
- For native targets instead, the communication consists of calls to
- ptrace and waits (via signals) or calls to poll/select (via file
- descriptors). In the current gdb, the code handling events related
- to the target resides in the wait_for_inferior function and in
- various target specific files (*-tdep.c).
+ GDB_NOTIFIER keeps track of the file descriptor based event
+ sources. ASYNC_EVENT_HANDLER_LIST keeps track of asynchronous
+ event sources that are signalled by some component of gdb, usually
+ a target_ops instance. Event sources for gdb are currently the UI
+ and the target. Gdb communicates with the command line user
+ interface via the readline library and usually communicates with
+ remote targets via a serial port. Serial ports are represented in
+ GDB as file descriptors and select/poll calls. For native targets
+ instead, the communication varies across operating system debug
+ APIs, but usually consists of calls to ptrace and waits (via
+ signals) or calls to poll/select (via file descriptors). In the
+ current gdb, the code handling events related to the target resides
+ in wait_for_inferior for synchronous targets; or, for asynchronous
+ capable targets, by having the target register either a target
+ controlled file descriptor and/or an asynchronous event source in
+ the event loop, with the fetch_inferior_event function as the event
+ callback. In both the synchronous and asynchronous cases, usually
+ the target event is collected through the target_wait interface.
+ The target is free to install other event sources in the event loop
+ if it so requires.
EVENT_QUEUE keeps track of the events that have happened during the
last iteration of the event loop, and need to be processed. An
functions that are invoked through traditional signal handlers.
The actions to be taken is response to such events will be executed
when the SIGHANDLER_LIST is scanned, the next time through the
- infinite loop.
+ infinite loop.
- Corollary tasks are the creation and deletion of event sources. */
+ Corollary tasks are the creation and deletion of event sources. */
typedef void *gdb_client_data;
struct async_signal_handler;
+struct async_event_handler;
typedef void (handler_func) (int, gdb_client_data);
typedef void (sig_handler_func) (gdb_client_data);
+typedef void (async_event_handler_func) (gdb_client_data);
typedef void (timer_handler_func) (gdb_client_data);
-/* Where to add an event onto the event queue, by queue_event. */
-typedef enum
- {
- /* Add at tail of queue. It will be processed in first in first
- out order. */
- TAIL,
- /* Add at head of queue. It will be processed in last in first out
- order. */
- HEAD
- }
-queue_position;
-
-/* Tell create_file_handler what events we are interested in.
- This is used by the select version of the event loop. */
-
-#define GDB_READABLE (1<<1)
-#define GDB_WRITABLE (1<<2)
-#define GDB_EXCEPTION (1<<3)
-
/* Exported functions from event-loop.c */
extern void start_event_loop (void);
-extern int gdb_do_one_event (void *data);
+extern int gdb_do_one_event (void);
extern void delete_file_handler (int fd);
-extern void add_file_handler (int fd, handler_func * proc, gdb_client_data client_data);
+extern void add_file_handler (int fd, handler_func *proc,
+ gdb_client_data client_data);
extern struct async_signal_handler *
- create_async_signal_handler (sig_handler_func * proc, gdb_client_data client_data);
-extern void delete_async_signal_handler (struct async_signal_handler **async_handler_ptr);
-extern int create_timer (int milliseconds, timer_handler_func * proc, gdb_client_data client_data);
+ create_async_signal_handler (sig_handler_func *proc,
+ gdb_client_data client_data);
+extern void delete_async_signal_handler (struct async_signal_handler **);
+extern int create_timer (int milliseconds,
+ timer_handler_func *proc,
+ gdb_client_data client_data);
extern void delete_timer (int id);
-/* Call the handler from HANDLER immediately. This function
- runs signal handlers when returning to the event loop would be too
- slow. Do not call this directly; use gdb_call_async_signal_handler,
- below, with IMMEDIATE_P == 1. */
-void call_async_signal_handler (struct async_signal_handler *handler);
-
-/* Call the handler from HANDLER the next time through the event loop.
- Do not call this directly; use gdb_call_async_signal_handler,
- below, with IMMEDIATE_P == 0. */
-void mark_async_signal_handler (struct async_signal_handler *handler);
-
-/* Wrapper for the body of signal handlers. Call this function from
- any SIGINT handler which needs to access GDB data structures or
- escape via longjmp. If IMMEDIATE_P is set, this triggers either
- immediately (for POSIX platforms), or from gdb_select (for
- MinGW). If IMMEDIATE_P is clear, the handler will run the next
- time we return to the event loop and any current select calls
- will be interrupted. */
-
-void gdb_call_async_signal_handler (struct async_signal_handler *handler,
- int immediate_p);
+/* Call the handler from HANDLER the next time through the event
+ loop. */
+extern void mark_async_signal_handler (struct async_signal_handler *handler);
+
+/* Returns true if HANDLER is marked ready. */
+
+extern int
+ async_signal_handler_is_marked (struct async_signal_handler *handler);
+
+/* Mark HANDLER as NOT ready. */
+
+extern void clear_async_signal_handler (struct async_signal_handler *handler);
+
+/* Create and register an asynchronous event source in the event loop,
+ and set PROC as its callback. CLIENT_DATA is passed as argument to
+ PROC upon its invocation. Returns a pointer to an opaque structure
+ used to mark as ready and to later delete this event source from
+ the event loop. */
+extern struct async_event_handler *
+ create_async_event_handler (async_event_handler_func *proc,
+ gdb_client_data client_data);
+
+/* Remove the event source pointed by HANDLER_PTR created by
+ CREATE_ASYNC_EVENT_HANDLER from the event loop, and release it. */
+extern void
+ delete_async_event_handler (struct async_event_handler **handler_ptr);
+
+/* Call the handler from HANDLER the next time through the event
+ loop. */
+extern void mark_async_event_handler (struct async_event_handler *handler);
+
+/* Mark the handler (ASYNC_HANDLER_PTR) as NOT ready. */
+
+extern void clear_async_event_handler (struct async_event_handler *handler);
+
+extern void initialize_async_signal_handlers (void);
+
+#endif /* EVENT_LOOP_H */
projects / deliverable / binutils-gdb.git / blobdiff