This moves event-loop.[ch] to gdbsupport/ and updates the uses in gdb.
gdb/ChangeLog
2020-04-13 Tom Tromey <tom@tromey.com>
* run-on-main-thread.c: Update include.
* unittests/main-thread-selftests.c: Update include.
* tui/tui-win.c: Update include.
* tui/tui-io.c: Update include.
* tui/tui-interp.c: Update include.
* tui/tui-hooks.c: Update include.
* top.h: Update include.
* top.c: Update include.
* ser-base.c: Update include.
* remote.c: Update include.
* remote-notif.c: Update include.
* remote-fileio.c: Update include.
* record-full.c: Update include.
* record-btrace.c: Update include.
* python/python.c: Update include.
* posix-hdep.c: Update include.
* mingw-hdep.c: Update include.
* mi/mi-main.c: Update include.
* mi/mi-interp.c: Update include.
* main.c: Update include.
* linux-nat.c: Update include.
* interps.c: Update include.
* infrun.c: Update include.
* inf-loop.c: Update include.
* event-top.c: Update include.
* event-loop.c: Move to ../gdbsupport/.
* event-loop.h: Move to ../gdbsupport/.
* async-event.h: Update include.
* Makefile.in (COMMON_SFILES, HFILES_NO_SRCDIR): Update.
gdbsupport/ChangeLog
2020-04-13 Tom Tromey <tom@tromey.com>
* event-loop.h: Move from ../gdb/.
* event-loop.cc: Move from ../gdb/.
+2020-04-13 Tom Tromey <tom@tromey.com>
+
+ * run-on-main-thread.c: Update include.
+ * unittests/main-thread-selftests.c: Update include.
+ * tui/tui-win.c: Update include.
+ * tui/tui-io.c: Update include.
+ * tui/tui-interp.c: Update include.
+ * tui/tui-hooks.c: Update include.
+ * top.h: Update include.
+ * top.c: Update include.
+ * ser-base.c: Update include.
+ * remote.c: Update include.
+ * remote-notif.c: Update include.
+ * remote-fileio.c: Update include.
+ * record-full.c: Update include.
+ * record-btrace.c: Update include.
+ * python/python.c: Update include.
+ * posix-hdep.c: Update include.
+ * mingw-hdep.c: Update include.
+ * mi/mi-main.c: Update include.
+ * mi/mi-interp.c: Update include.
+ * main.c: Update include.
+ * linux-nat.c: Update include.
+ * interps.c: Update include.
+ * infrun.c: Update include.
+ * inf-loop.c: Update include.
+ * event-top.c: Update include.
+ * event-loop.c: Move to ../gdbsupport/.
+ * event-loop.h: Move to ../gdbsupport/.
+ * async-event.h: Update include.
+ * Makefile.in (COMMON_SFILES, HFILES_NO_SRCDIR): Update.
+
2020-04-13 Tom Tromey <tom@tromey.com>
* tui/tui-win.c: Include async-event.h.
dwarf2/section.c \
dwarf2/stringify.c \
eval.c \
- event-loop.c \
event-top.c \
exceptions.c \
exec.c \
dwarf2/index-common.h \
dwarf2/loc.h \
dwarf2/read.h \
- event-loop.h \
event-top.h \
exceptions.h \
exec.h \
#ifndef ASYNC_EVENT_H
#define ASYNC_EVENT_H
-#include "event-loop.h"
+#include "gdbsupport/event-loop.h"
struct async_signal_handler;
struct async_event_handler;
+++ /dev/null
-/* Event loop machinery for GDB, the GNU debugger.
- Copyright (C) 1999-2020 Free Software Foundation, Inc.
- Written by Elena Zannoni <ezannoni@cygnus.com> of Cygnus Solutions.
-
- This file is part of GDB.
-
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 3 of the License, or
- (at your option) any later version.
-
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
-
- You should have received a copy of the GNU General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>. */
-
-#include "defs.h"
-#include "event-loop.h"
-
-#include <chrono>
-
-#ifdef HAVE_POLL
-#if defined (HAVE_POLL_H)
-#include <poll.h>
-#elif defined (HAVE_SYS_POLL_H)
-#include <sys/poll.h>
-#endif
-#endif
-
-#include <sys/types.h>
-#include "gdbsupport/gdb_sys_time.h"
-#include "gdbsupport/gdb_select.h"
-
-/* 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)
-
-/* Information about each file descriptor we register with the event
- loop. */
-
-typedef struct file_handler
- {
- int fd; /* File descriptor. */
- int mask; /* Events we want to monitor: POLLIN, etc. */
- int ready_mask; /* Events that have been seen since
- the last time. */
- handler_func *proc; /* Procedure to call when fd is ready. */
- gdb_client_data client_data; /* Argument to pass to proc. */
- int error; /* Was an error detected on this fd? */
- struct file_handler *next_file; /* Next registered file descriptor. */
- }
-file_handler;
-
-/* Gdb_notifier is just a list of file descriptors gdb is interested in.
- These are the input file descriptor, and the target file
- descriptor. We have two flavors of the notifier, one for platforms
- that have the POLL function, the other for those that don't, and
- only support SELECT. Each of the elements in the gdb_notifier list is
- basically a description of what kind of events gdb is interested
- in, for each fd. */
-
-/* As of 1999-04-30 only the input file descriptor is registered with the
- event loop. */
-
-/* Do we use poll or select ? */
-#ifdef HAVE_POLL
-#define USE_POLL 1
-#else
-#define USE_POLL 0
-#endif /* HAVE_POLL */
-
-static unsigned char use_poll = USE_POLL;
-
-#ifdef USE_WIN32API
-#include <windows.h>
-#include <io.h>
-#endif
-
-static struct
- {
- /* Ptr to head of file handler list. */
- file_handler *first_file_handler;
-
- /* Next file handler to handle, for the select variant. To level
- the fairness across event sources, we serve file handlers in a
- round-robin-like fashion. The number and order of the polled
- file handlers may change between invocations, but this is good
- enough. */
- file_handler *next_file_handler;
-
-#ifdef HAVE_POLL
- /* Ptr to array of pollfd structures. */
- struct pollfd *poll_fds;
-
- /* Next file descriptor to handle, for the poll variant. To level
- the fairness across event sources, we poll the file descriptors
- in a round-robin-like fashion. The number and order of the
- polled file descriptors may change between invocations, but
- this is good enough. */
- int next_poll_fds_index;
-
- /* Timeout in milliseconds for calls to poll(). */
- int poll_timeout;
-#endif
-
- /* Masks to be used in the next call to select.
- Bits are set in response to calls to create_file_handler. */
- fd_set check_masks[3];
-
- /* What file descriptors were found ready by select. */
- fd_set ready_masks[3];
-
- /* Number of file descriptors to monitor (for poll). */
- /* Number of valid bits (highest fd value + 1) (for select). */
- int num_fds;
-
- /* Time structure for calls to select(). */
- struct timeval select_timeout;
-
- /* Flag to tell whether the timeout should be used. */
- int timeout_valid;
- }
-gdb_notifier;
-
-/* Structure associated with a timer. PROC will be executed at the
- first occasion after WHEN. */
-struct gdb_timer
- {
- std::chrono::steady_clock::time_point when;
- int timer_id;
- struct gdb_timer *next;
- timer_handler_func *proc; /* Function to call to do the work. */
- gdb_client_data client_data; /* Argument to async_handler_func. */
- };
-
-/* List of currently active timers. It is sorted in order of
- increasing timers. */
-static struct
- {
- /* Pointer to first in timer list. */
- struct gdb_timer *first_timer;
-
- /* Id of the last timer created. */
- int num_timers;
- }
-timer_list;
-
-static void create_file_handler (int fd, int mask, handler_func *proc,
- gdb_client_data client_data);
-static int gdb_wait_for_event (int);
-static int update_wait_timeout (void);
-static int poll_timers (void);
-\f
-/* Process one high level event. If nothing is ready at this time,
- wait for something to happen (via gdb_wait_for_event), then process
- it. Returns >0 if something was done otherwise returns <0 (this
- can happen if there are no event sources to wait for). */
-
-int
-gdb_do_one_event (void)
-{
- static int event_source_head = 0;
- const int number_of_sources = 3;
- int current = 0;
-
- /* First let's see if there are any asynchronous signal handlers
- that are ready. These would be the result of invoking any of the
- signal handlers. */
- if (invoke_async_signal_handlers ())
- return 1;
-
- /* To level the fairness across event sources, we poll them in a
- round-robin fashion. */
- for (current = 0; current < number_of_sources; current++)
- {
- int res;
-
- switch (event_source_head)
- {
- case 0:
- /* Are any timers that are ready? */
- res = poll_timers ();
- break;
- case 1:
- /* Are there events already waiting to be collected on the
- monitored file descriptors? */
- res = gdb_wait_for_event (0);
- break;
- case 2:
- /* Are there any asynchronous event handlers ready? */
- res = check_async_event_handlers ();
- break;
- default:
- internal_error (__FILE__, __LINE__,
- "unexpected event_source_head %d",
- event_source_head);
- }
-
- event_source_head++;
- if (event_source_head == number_of_sources)
- event_source_head = 0;
-
- if (res > 0)
- return 1;
- }
-
- /* Block waiting for a new event. If gdb_wait_for_event returns -1,
- we should get out because this means that there are no event
- sources left. This will make the event loop stop, and the
- application exit. */
-
- if (gdb_wait_for_event (1) < 0)
- return -1;
-
- /* If gdb_wait_for_event has returned 1, it means that one event has
- been handled. We break out of the loop. */
- return 1;
-}
-
-\f
-
-/* Wrapper function for create_file_handler, so that the caller
- doesn't have to know implementation details about the use of poll
- vs. select. */
-void
-add_file_handler (int fd, handler_func * proc, gdb_client_data client_data)
-{
-#ifdef HAVE_POLL
- struct pollfd fds;
-#endif
-
- if (use_poll)
- {
-#ifdef HAVE_POLL
- /* Check to see if poll () is usable. If not, we'll switch to
- use select. This can happen on systems like
- m68k-motorola-sys, `poll' cannot be used to wait for `stdin'.
- On m68k-motorola-sysv, tty's are not stream-based and not
- `poll'able. */
- fds.fd = fd;
- fds.events = POLLIN;
- if (poll (&fds, 1, 0) == 1 && (fds.revents & POLLNVAL))
- use_poll = 0;
-#else
- internal_error (__FILE__, __LINE__,
- _("use_poll without HAVE_POLL"));
-#endif /* HAVE_POLL */
- }
- if (use_poll)
- {
-#ifdef HAVE_POLL
- create_file_handler (fd, POLLIN, proc, client_data);
-#else
- internal_error (__FILE__, __LINE__,
- _("use_poll without HAVE_POLL"));
-#endif
- }
- else
- create_file_handler (fd, GDB_READABLE | GDB_EXCEPTION,
- proc, client_data);
-}
-
-/* Add a file handler/descriptor to the list of descriptors we are
- interested in.
-
- FD is the file descriptor for the file/stream to be listened to.
-
- For the poll case, MASK is a combination (OR) of POLLIN,
- POLLRDNORM, POLLRDBAND, POLLPRI, POLLOUT, POLLWRNORM, POLLWRBAND:
- these are the events we are interested in. If any of them occurs,
- proc should be called.
-
- For the select case, MASK is a combination of READABLE, WRITABLE,
- EXCEPTION. PROC is the procedure that will be called when an event
- occurs for FD. CLIENT_DATA is the argument to pass to PROC. */
-
-static void
-create_file_handler (int fd, int mask, handler_func * proc,
- gdb_client_data client_data)
-{
- file_handler *file_ptr;
-
- /* Do we already have a file handler for this file? (We may be
- changing its associated procedure). */
- for (file_ptr = gdb_notifier.first_file_handler; file_ptr != NULL;
- file_ptr = file_ptr->next_file)
- {
- if (file_ptr->fd == fd)
- break;
- }
-
- /* It is a new file descriptor. Add it to the list. Otherwise, just
- change the data associated with it. */
- if (file_ptr == NULL)
- {
- file_ptr = XNEW (file_handler);
- file_ptr->fd = fd;
- file_ptr->ready_mask = 0;
- file_ptr->next_file = gdb_notifier.first_file_handler;
- gdb_notifier.first_file_handler = file_ptr;
-
- if (use_poll)
- {
-#ifdef HAVE_POLL
- gdb_notifier.num_fds++;
- if (gdb_notifier.poll_fds)
- gdb_notifier.poll_fds =
- (struct pollfd *) xrealloc (gdb_notifier.poll_fds,
- (gdb_notifier.num_fds
- * sizeof (struct pollfd)));
- else
- gdb_notifier.poll_fds =
- XNEW (struct pollfd);
- (gdb_notifier.poll_fds + gdb_notifier.num_fds - 1)->fd = fd;
- (gdb_notifier.poll_fds + gdb_notifier.num_fds - 1)->events = mask;
- (gdb_notifier.poll_fds + gdb_notifier.num_fds - 1)->revents = 0;
-#else
- internal_error (__FILE__, __LINE__,
- _("use_poll without HAVE_POLL"));
-#endif /* HAVE_POLL */
- }
- else
- {
- if (mask & GDB_READABLE)
- FD_SET (fd, &gdb_notifier.check_masks[0]);
- else
- FD_CLR (fd, &gdb_notifier.check_masks[0]);
-
- if (mask & GDB_WRITABLE)
- FD_SET (fd, &gdb_notifier.check_masks[1]);
- else
- FD_CLR (fd, &gdb_notifier.check_masks[1]);
-
- if (mask & GDB_EXCEPTION)
- FD_SET (fd, &gdb_notifier.check_masks[2]);
- else
- FD_CLR (fd, &gdb_notifier.check_masks[2]);
-
- if (gdb_notifier.num_fds <= fd)
- gdb_notifier.num_fds = fd + 1;
- }
- }
-
- file_ptr->proc = proc;
- file_ptr->client_data = client_data;
- file_ptr->mask = mask;
-}
-
-/* Return the next file handler to handle, and advance to the next
- file handler, wrapping around if the end of the list is
- reached. */
-
-static file_handler *
-get_next_file_handler_to_handle_and_advance (void)
-{
- file_handler *curr_next;
-
- /* The first time around, this is still NULL. */
- if (gdb_notifier.next_file_handler == NULL)
- gdb_notifier.next_file_handler = gdb_notifier.first_file_handler;
-
- curr_next = gdb_notifier.next_file_handler;
- gdb_assert (curr_next != NULL);
-
- /* Advance. */
- gdb_notifier.next_file_handler = curr_next->next_file;
- /* Wrap around, if necessary. */
- if (gdb_notifier.next_file_handler == NULL)
- gdb_notifier.next_file_handler = gdb_notifier.first_file_handler;
-
- return curr_next;
-}
-
-/* Remove the file descriptor FD from the list of monitored fd's:
- i.e. we don't care anymore about events on the FD. */
-void
-delete_file_handler (int fd)
-{
- file_handler *file_ptr, *prev_ptr = NULL;
- int i;
-#ifdef HAVE_POLL
- int j;
- struct pollfd *new_poll_fds;
-#endif
-
- /* Find the entry for the given file. */
-
- for (file_ptr = gdb_notifier.first_file_handler; file_ptr != NULL;
- file_ptr = file_ptr->next_file)
- {
- if (file_ptr->fd == fd)
- break;
- }
-
- if (file_ptr == NULL)
- return;
-
- if (use_poll)
- {
-#ifdef HAVE_POLL
- /* Create a new poll_fds array by copying every fd's information
- but the one we want to get rid of. */
-
- new_poll_fds = (struct pollfd *)
- xmalloc ((gdb_notifier.num_fds - 1) * sizeof (struct pollfd));
-
- for (i = 0, j = 0; i < gdb_notifier.num_fds; i++)
- {
- if ((gdb_notifier.poll_fds + i)->fd != fd)
- {
- (new_poll_fds + j)->fd = (gdb_notifier.poll_fds + i)->fd;
- (new_poll_fds + j)->events = (gdb_notifier.poll_fds + i)->events;
- (new_poll_fds + j)->revents
- = (gdb_notifier.poll_fds + i)->revents;
- j++;
- }
- }
- xfree (gdb_notifier.poll_fds);
- gdb_notifier.poll_fds = new_poll_fds;
- gdb_notifier.num_fds--;
-#else
- internal_error (__FILE__, __LINE__,
- _("use_poll without HAVE_POLL"));
-#endif /* HAVE_POLL */
- }
- else
- {
- if (file_ptr->mask & GDB_READABLE)
- FD_CLR (fd, &gdb_notifier.check_masks[0]);
- if (file_ptr->mask & GDB_WRITABLE)
- FD_CLR (fd, &gdb_notifier.check_masks[1]);
- if (file_ptr->mask & GDB_EXCEPTION)
- FD_CLR (fd, &gdb_notifier.check_masks[2]);
-
- /* Find current max fd. */
-
- if ((fd + 1) == gdb_notifier.num_fds)
- {
- gdb_notifier.num_fds--;
- for (i = gdb_notifier.num_fds; i; i--)
- {
- if (FD_ISSET (i - 1, &gdb_notifier.check_masks[0])
- || FD_ISSET (i - 1, &gdb_notifier.check_masks[1])
- || FD_ISSET (i - 1, &gdb_notifier.check_masks[2]))
- break;
- }
- gdb_notifier.num_fds = i;
- }
- }
-
- /* Deactivate the file descriptor, by clearing its mask,
- so that it will not fire again. */
-
- file_ptr->mask = 0;
-
- /* If this file handler was going to be the next one to be handled,
- advance to the next's next, if any. */
- if (gdb_notifier.next_file_handler == file_ptr)
- {
- if (file_ptr->next_file == NULL
- && file_ptr == gdb_notifier.first_file_handler)
- gdb_notifier.next_file_handler = NULL;
- else
- get_next_file_handler_to_handle_and_advance ();
- }
-
- /* Get rid of the file handler in the file handler list. */
- if (file_ptr == gdb_notifier.first_file_handler)
- gdb_notifier.first_file_handler = file_ptr->next_file;
- else
- {
- for (prev_ptr = gdb_notifier.first_file_handler;
- prev_ptr->next_file != file_ptr;
- prev_ptr = prev_ptr->next_file)
- ;
- prev_ptr->next_file = file_ptr->next_file;
- }
- xfree (file_ptr);
-}
-
-/* Handle the given event by calling the procedure associated to the
- corresponding file handler. */
-
-static void
-handle_file_event (file_handler *file_ptr, int ready_mask)
-{
- int mask;
-#ifdef HAVE_POLL
- int error_mask;
-#endif
-
- {
- {
- /* With poll, the ready_mask could have any of three events
- set to 1: POLLHUP, POLLERR, POLLNVAL. These events
- cannot be used in the requested event mask (events), but
- they can be returned in the return mask (revents). We
- need to check for those event too, and add them to the
- mask which will be passed to the handler. */
-
- /* See if the desired events (mask) match the received
- events (ready_mask). */
-
- if (use_poll)
- {
-#ifdef HAVE_POLL
- /* POLLHUP means EOF, but can be combined with POLLIN to
- signal more data to read. */
- error_mask = POLLHUP | POLLERR | POLLNVAL;
- mask = ready_mask & (file_ptr->mask | error_mask);
-
- if ((mask & (POLLERR | POLLNVAL)) != 0)
- {
- /* Work in progress. We may need to tell somebody
- what kind of error we had. */
- if (mask & POLLERR)
- warning (_("Error detected on fd %d"), file_ptr->fd);
- if (mask & POLLNVAL)
- warning (_("Invalid or non-`poll'able fd %d"),
- file_ptr->fd);
- file_ptr->error = 1;
- }
- else
- file_ptr->error = 0;
-#else
- internal_error (__FILE__, __LINE__,
- _("use_poll without HAVE_POLL"));
-#endif /* HAVE_POLL */
- }
- else
- {
- if (ready_mask & GDB_EXCEPTION)
- {
- warning (_("Exception condition detected on fd %d"),
- file_ptr->fd);
- file_ptr->error = 1;
- }
- else
- file_ptr->error = 0;
- mask = ready_mask & file_ptr->mask;
- }
-
- /* If there was a match, then call the handler. */
- if (mask != 0)
- (*file_ptr->proc) (file_ptr->error, file_ptr->client_data);
- }
- }
-}
-
-/* Wait for new events on the monitored file descriptors. Run the
- event handler if the first descriptor that is detected by the poll.
- If BLOCK and if there are no events, this function will block in
- the call to poll. Return 1 if an event was handled. Return -1 if
- there are no file descriptors to monitor. Return 1 if an event was
- handled, otherwise returns 0. */
-
-static int
-gdb_wait_for_event (int block)
-{
- file_handler *file_ptr;
- int num_found = 0;
-
- /* Make sure all output is done before getting another event. */
- flush_streams ();
-
- if (gdb_notifier.num_fds == 0)
- return -1;
-
- if (block)
- update_wait_timeout ();
-
- if (use_poll)
- {
-#ifdef HAVE_POLL
- int timeout;
-
- if (block)
- timeout = gdb_notifier.timeout_valid ? gdb_notifier.poll_timeout : -1;
- else
- timeout = 0;
-
- num_found = poll (gdb_notifier.poll_fds,
- (unsigned long) gdb_notifier.num_fds, timeout);
-
- /* Don't print anything if we get out of poll because of a
- signal. */
- if (num_found == -1 && errno != EINTR)
- perror_with_name (("poll"));
-#else
- internal_error (__FILE__, __LINE__,
- _("use_poll without HAVE_POLL"));
-#endif /* HAVE_POLL */
- }
- else
- {
- struct timeval select_timeout;
- struct timeval *timeout_p;
-
- if (block)
- timeout_p = gdb_notifier.timeout_valid
- ? &gdb_notifier.select_timeout : NULL;
- else
- {
- memset (&select_timeout, 0, sizeof (select_timeout));
- timeout_p = &select_timeout;
- }
-
- gdb_notifier.ready_masks[0] = gdb_notifier.check_masks[0];
- gdb_notifier.ready_masks[1] = gdb_notifier.check_masks[1];
- gdb_notifier.ready_masks[2] = gdb_notifier.check_masks[2];
- num_found = gdb_select (gdb_notifier.num_fds,
- &gdb_notifier.ready_masks[0],
- &gdb_notifier.ready_masks[1],
- &gdb_notifier.ready_masks[2],
- timeout_p);
-
- /* Clear the masks after an error from select. */
- if (num_found == -1)
- {
- FD_ZERO (&gdb_notifier.ready_masks[0]);
- FD_ZERO (&gdb_notifier.ready_masks[1]);
- FD_ZERO (&gdb_notifier.ready_masks[2]);
-
- /* Dont print anything if we got a signal, let gdb handle
- it. */
- if (errno != EINTR)
- perror_with_name (("select"));
- }
- }
-
- /* Avoid looking at poll_fds[i]->revents if no event fired. */
- if (num_found <= 0)
- return 0;
-
- /* Run event handlers. We always run just one handler and go back
- to polling, in case a handler changes the notifier list. Since
- events for sources we haven't consumed yet wake poll/select
- immediately, no event is lost. */
-
- /* To level the fairness across event descriptors, we handle them in
- a round-robin-like fashion. The number and order of descriptors
- may change between invocations, but this is good enough. */
- if (use_poll)
- {
-#ifdef HAVE_POLL
- int i;
- int mask;
-
- while (1)
- {
- if (gdb_notifier.next_poll_fds_index >= gdb_notifier.num_fds)
- gdb_notifier.next_poll_fds_index = 0;
- i = gdb_notifier.next_poll_fds_index++;
-
- gdb_assert (i < gdb_notifier.num_fds);
- if ((gdb_notifier.poll_fds + i)->revents)
- break;
- }
-
- for (file_ptr = gdb_notifier.first_file_handler;
- file_ptr != NULL;
- file_ptr = file_ptr->next_file)
- {
- if (file_ptr->fd == (gdb_notifier.poll_fds + i)->fd)
- break;
- }
- gdb_assert (file_ptr != NULL);
-
- mask = (gdb_notifier.poll_fds + i)->revents;
- handle_file_event (file_ptr, mask);
- return 1;
-#else
- internal_error (__FILE__, __LINE__,
- _("use_poll without HAVE_POLL"));
-#endif /* HAVE_POLL */
- }
- else
- {
- /* See comment about even source fairness above. */
- int mask = 0;
-
- do
- {
- file_ptr = get_next_file_handler_to_handle_and_advance ();
-
- if (FD_ISSET (file_ptr->fd, &gdb_notifier.ready_masks[0]))
- mask |= GDB_READABLE;
- if (FD_ISSET (file_ptr->fd, &gdb_notifier.ready_masks[1]))
- mask |= GDB_WRITABLE;
- if (FD_ISSET (file_ptr->fd, &gdb_notifier.ready_masks[2]))
- mask |= GDB_EXCEPTION;
- }
- while (mask == 0);
-
- handle_file_event (file_ptr, mask);
- return 1;
- }
- return 0;
-}
-\f
-/* Create a timer that will expire in MS milliseconds from now. When
- the timer is ready, PROC will be executed. At creation, the timer
- is added to the timers queue. This queue is kept sorted in order
- of increasing timers. Return a handle to the timer struct. */
-
-int
-create_timer (int ms, timer_handler_func *proc,
- gdb_client_data client_data)
-{
- using namespace std::chrono;
- struct gdb_timer *timer_ptr, *timer_index, *prev_timer;
-
- steady_clock::time_point time_now = steady_clock::now ();
-
- timer_ptr = new gdb_timer ();
- timer_ptr->when = time_now + milliseconds (ms);
- timer_ptr->proc = proc;
- timer_ptr->client_data = client_data;
- timer_list.num_timers++;
- timer_ptr->timer_id = timer_list.num_timers;
-
- /* Now add the timer to the timer queue, making sure it is sorted in
- increasing order of expiration. */
-
- for (timer_index = timer_list.first_timer;
- timer_index != NULL;
- timer_index = timer_index->next)
- {
- if (timer_index->when > timer_ptr->when)
- break;
- }
-
- if (timer_index == timer_list.first_timer)
- {
- timer_ptr->next = timer_list.first_timer;
- timer_list.first_timer = timer_ptr;
-
- }
- else
- {
- for (prev_timer = timer_list.first_timer;
- prev_timer->next != timer_index;
- prev_timer = prev_timer->next)
- ;
-
- prev_timer->next = timer_ptr;
- timer_ptr->next = timer_index;
- }
-
- gdb_notifier.timeout_valid = 0;
- return timer_ptr->timer_id;
-}
-
-/* There is a chance that the creator of the timer wants to get rid of
- it before it expires. */
-void
-delete_timer (int id)
-{
- struct gdb_timer *timer_ptr, *prev_timer = NULL;
-
- /* Find the entry for the given timer. */
-
- for (timer_ptr = timer_list.first_timer; timer_ptr != NULL;
- timer_ptr = timer_ptr->next)
- {
- if (timer_ptr->timer_id == id)
- break;
- }
-
- if (timer_ptr == NULL)
- return;
- /* Get rid of the timer in the timer list. */
- if (timer_ptr == timer_list.first_timer)
- timer_list.first_timer = timer_ptr->next;
- else
- {
- for (prev_timer = timer_list.first_timer;
- prev_timer->next != timer_ptr;
- prev_timer = prev_timer->next)
- ;
- prev_timer->next = timer_ptr->next;
- }
- delete timer_ptr;
-
- gdb_notifier.timeout_valid = 0;
-}
-
-/* Convert a std::chrono duration to a struct timeval. */
-
-template<typename Duration>
-static struct timeval
-duration_cast_timeval (const Duration &d)
-{
- using namespace std::chrono;
- seconds sec = duration_cast<seconds> (d);
- microseconds msec = duration_cast<microseconds> (d - sec);
-
- struct timeval tv;
- tv.tv_sec = sec.count ();
- tv.tv_usec = msec.count ();
- return tv;
-}
-
-/* Update the timeout for the select() or poll(). Returns true if the
- timer has already expired, false otherwise. */
-
-static int
-update_wait_timeout (void)
-{
- if (timer_list.first_timer != NULL)
- {
- using namespace std::chrono;
- steady_clock::time_point time_now = steady_clock::now ();
- struct timeval timeout;
-
- if (timer_list.first_timer->when < time_now)
- {
- /* It expired already. */
- timeout.tv_sec = 0;
- timeout.tv_usec = 0;
- }
- else
- {
- steady_clock::duration d = timer_list.first_timer->when - time_now;
- timeout = duration_cast_timeval (d);
- }
-
- /* Update the timeout for select/ poll. */
- if (use_poll)
- {
-#ifdef HAVE_POLL
- gdb_notifier.poll_timeout = timeout.tv_sec * 1000;
-#else
- internal_error (__FILE__, __LINE__,
- _("use_poll without HAVE_POLL"));
-#endif /* HAVE_POLL */
- }
- else
- {
- gdb_notifier.select_timeout.tv_sec = timeout.tv_sec;
- gdb_notifier.select_timeout.tv_usec = timeout.tv_usec;
- }
- gdb_notifier.timeout_valid = 1;
-
- if (timer_list.first_timer->when < time_now)
- return 1;
- }
- else
- gdb_notifier.timeout_valid = 0;
-
- return 0;
-}
-
-/* Check whether a timer in the timers queue is ready. If a timer is
- ready, call its handler and return. Update the timeout for the
- select() or poll() as well. Return 1 if an event was handled,
- otherwise returns 0.*/
-
-static int
-poll_timers (void)
-{
- if (update_wait_timeout ())
- {
- struct gdb_timer *timer_ptr = timer_list.first_timer;
- timer_handler_func *proc = timer_ptr->proc;
- gdb_client_data client_data = timer_ptr->client_data;
-
- /* Get rid of the timer from the beginning of the list. */
- timer_list.first_timer = timer_ptr->next;
-
- /* Delete the timer before calling the callback, not after, in
- case the callback itself decides to try deleting the timer
- too. */
- delete timer_ptr;
-
- /* Call the procedure associated with that timer. */
- (proc) (client_data);
-
- return 1;
- }
-
- return 0;
-}
+++ /dev/null
-/* Definitions used by the GDB event loop.
- Copyright (C) 1999-2020 Free Software Foundation, Inc.
- Written by Elena Zannoni <ezannoni@cygnus.com> of Cygnus Solutions.
-
- This file is part of GDB.
-
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 3 of the License, or
- (at your option) any later version.
-
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
-
- You should have received a copy of the GNU General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>. */
-
-#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
- sources to listen on. External event sources can be plugged into
- the loop.
-
- 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 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
- event is represented by a procedure to be invoked in order to
- process the event. The queue is scanned head to tail. If the
- event of interest is a change of state in a file descriptor, then a
- call to poll or select will be made to detect it.
-
- If the events generate signals, they are also queued by special
- 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.
-
- Corollary tasks are the creation and deletion of event sources. */
-
-typedef void *gdb_client_data;
-typedef void (handler_func) (int, gdb_client_data);
-typedef void (timer_handler_func) (gdb_client_data);
-
-/* Exported functions from event-loop.c */
-
-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 int create_timer (int milliseconds,
- timer_handler_func *proc,
- gdb_client_data client_data);
-extern void delete_timer (int id);
-
-/* Must be defined by client. */
-
-extern void handle_event_loop_exception (const gdb_exception &);
-
-/* Must be defined by client. Returns true if any signal handler was
- ready. */
-
-extern int invoke_async_signal_handlers ();
-
-/* Must be defined by client. Returns true if any event handler was
- ready. */
-
-extern int check_async_event_handlers ();
-
-#endif /* EVENT_LOOP_H */
#include "infrun.h"
#include "target.h"
#include "terminal.h"
-#include "event-loop.h"
+#include "gdbsupport/event-loop.h"
#include "event-top.h"
#include "interps.h"
#include <signal.h>
#include "defs.h"
#include "inferior.h"
#include "infrun.h"
-#include "event-loop.h"
+#include "gdbsupport/event-loop.h"
#include "event-top.h"
#include "inf-loop.h"
#include "remote.h"
#include "target-dcache.h"
#include "terminal.h"
#include "solist.h"
-#include "event-loop.h"
+#include "gdbsupport/event-loop.h"
#include "thread-fsm.h"
#include "gdbsupport/enum-flags.h"
#include "progspace-and-thread.h"
#include "defs.h"
#include "gdbcmd.h"
#include "ui-out.h"
-#include "event-loop.h"
+#include "gdbsupport/event-loop.h"
#include "event-top.h"
#include "interps.h"
#include "completer.h"
#include <sys/stat.h> /* for struct stat */
#include <fcntl.h> /* for O_RDONLY */
#include "inf-loop.h"
-#include "event-loop.h"
+#include "gdbsupport/event-loop.h"
#include "event-top.h"
#include <pwd.h>
#include <sys/types.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <ctype.h>
-#include "event-loop.h"
+#include "gdbsupport/event-loop.h"
#include "ui-out.h"
#include "interps.h"
#include "interps.h"
#include "event-top.h"
-#include "event-loop.h"
+#include "gdbsupport/event-loop.h"
#include "inferior.h"
#include "infrun.h"
#include "ui-out.h"
#include "ui-out.h"
#include "mi-out.h"
#include "interps.h"
-#include "event-loop.h"
+#include "gdbsupport/event-loop.h"
#include "event-top.h"
#include "gdbcore.h" /* For write_memory(). */
#include "value.h"
#include "defs.h"
#include "main.h"
#include "serial.h"
-#include "event-loop.h"
+#include "gdbsupport/event-loop.h"
#include "gdbsupport/gdb_select.h"
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
-#include "event-loop.h"
+#include "gdbsupport/event-loop.h"
#include "gdbsupport/gdb_select.h"
#include "objfiles.h"
#include "value.h"
#include "language.h"
-#include "event-loop.h"
+#include "gdbsupport/event-loop.h"
#include "readline/tilde.h"
#include "python.h"
#include "extension-priv.h"
#include "frame-unwind.h"
#include "hashtab.h"
#include "infrun.h"
-#include "event-loop.h"
+#include "gdbsupport/event-loop.h"
#include "inf-loop.h"
#include "inferior.h"
#include <algorithm>
#include "record-full.h"
#include "elf-bfd.h"
#include "gcore.h"
-#include "event-loop.h"
+#include "gdbsupport/event-loop.h"
#include "inf-loop.h"
#include "gdb_bfd.h"
#include "observable.h"
#include "gdbsupport/gdb_wait.h"
#include <sys/stat.h>
#include "remote-fileio.h"
-#include "event-loop.h"
+#include "gdbsupport/event-loop.h"
#include "target.h"
#include "filenames.h"
#include "gdbsupport/filestuff.h"
#include "remote.h"
#include "remote-notif.h"
#include "observable.h"
-#include "event-loop.h"
+#include "gdbsupport/event-loop.h"
#include "target.h"
#include "inferior.h"
#include "infrun.h"
#include "gdbsupport/gdb_sys_time.h"
-#include "event-loop.h"
+#include "gdbsupport/event-loop.h"
#include "event-top.h"
#include "inf-loop.h"
#if CXX_STD_THREAD
#include <mutex>
#endif
-#include "event-loop.h"
+#include "gdbsupport/event-loop.h"
/* The serial event used when posting runnables. */
#include "defs.h"
#include "serial.h"
#include "ser-base.h"
-#include "event-loop.h"
+#include "gdbsupport/event-loop.h"
#include "gdbsupport/gdb_select.h"
#include "gdbsupport/gdb_sys_time.h"
#include "gdbsupport/version.h"
#include "serial.h"
#include "main.h"
-#include "event-loop.h"
+#include "gdbsupport/event-loop.h"
#include "gdbthread.h"
#include "extension.h"
#include "interps.h"
#define TOP_H
#include "gdbsupport/buffer.h"
-#include "event-loop.h"
+#include "gdbsupport/event-loop.h"
#include "value.h"
struct tl_interp_info;
#include "objfiles.h"
#include "target.h"
#include "gdbcore.h"
-#include "event-loop.h"
+#include "gdbsupport/event-loop.h"
#include "event-top.h"
#include "frame.h"
#include "breakpoint.h"
#include "interps.h"
#include "top.h"
#include "event-top.h"
-#include "event-loop.h"
+#include "gdbsupport/event-loop.h"
#include "ui-out.h"
#include "cli-out.h"
#include "tui/tui-data.h"
#include "defs.h"
#include "target.h"
-#include "event-loop.h"
+#include "gdbsupport/event-loop.h"
#include "event-top.h"
#include "command.h"
#include "top.h"
#include "cli/cli-style.h"
#include "top.h"
#include "source.h"
-#include "event-loop.h"
+#include "gdbsupport/event-loop.h"
#include "gdbcmd.h"
#include "async-event.h"
#include "gdbsupport/selftest.h"
#include "gdbsupport/block-signals.h"
#include "run-on-main-thread.h"
-#include "event-loop.h"
+#include "gdbsupport/event-loop.h"
#if CXX_STD_THREAD
#include <thread>
#endif
+2020-04-13 Tom Tromey <tom@tromey.com>
+
+ * event-loop.h: Move from ../gdb/.
+ * event-loop.cc: Move from ../gdb/.
+
2020-04-13 Tom Tromey <tom@tromey.com>
* errors.h (flush_streams): Declare.
common-utils.cc \
environ.cc \
errors.cc \
+ event-loop.cc \
fileio.cc \
filestuff.cc \
format.cc \
buffer.$(OBJEXT) cleanups.$(OBJEXT) common-debug.$(OBJEXT) \
common-exceptions.$(OBJEXT) common-inferior.$(OBJEXT) \
common-regcache.$(OBJEXT) common-utils.$(OBJEXT) \
- environ.$(OBJEXT) errors.$(OBJEXT) fileio.$(OBJEXT) \
- filestuff.$(OBJEXT) format.$(OBJEXT) gdb-dlfcn.$(OBJEXT) \
- gdb_tilde_expand.$(OBJEXT) gdb_wait.$(OBJEXT) \
- gdb_vecs.$(OBJEXT) job-control.$(OBJEXT) netstuff.$(OBJEXT) \
- new-op.$(OBJEXT) pathstuff.$(OBJEXT) print-utils.$(OBJEXT) \
- ptid.$(OBJEXT) rsp-low.$(OBJEXT) run-time-clock.$(OBJEXT) \
- safe-strerror.$(OBJEXT) scoped_mmap.$(OBJEXT) \
- signals.$(OBJEXT) signals-state-save-restore.$(OBJEXT) \
- tdesc.$(OBJEXT) thread-pool.$(OBJEXT) xml-utils.$(OBJEXT) \
- $(am__objects_1)
+ environ.$(OBJEXT) errors.$(OBJEXT) event-loop.$(OBJEXT) \
+ fileio.$(OBJEXT) filestuff.$(OBJEXT) format.$(OBJEXT) \
+ gdb-dlfcn.$(OBJEXT) gdb_tilde_expand.$(OBJEXT) \
+ gdb_wait.$(OBJEXT) gdb_vecs.$(OBJEXT) job-control.$(OBJEXT) \
+ netstuff.$(OBJEXT) new-op.$(OBJEXT) pathstuff.$(OBJEXT) \
+ print-utils.$(OBJEXT) ptid.$(OBJEXT) rsp-low.$(OBJEXT) \
+ run-time-clock.$(OBJEXT) safe-strerror.$(OBJEXT) \
+ scoped_mmap.$(OBJEXT) signals.$(OBJEXT) \
+ signals-state-save-restore.$(OBJEXT) tdesc.$(OBJEXT) \
+ thread-pool.$(OBJEXT) xml-utils.$(OBJEXT) $(am__objects_1)
libgdbsupport_a_OBJECTS = $(am_libgdbsupport_a_OBJECTS)
AM_V_P = $(am__v_P_@AM_V@)
am__v_P_ = $(am__v_P_@AM_DEFAULT_V@)
common-utils.cc \
environ.cc \
errors.cc \
+ event-loop.cc \
fileio.cc \
filestuff.cc \
format.cc \
@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/common-utils.Po@am__quote@
@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/environ.Po@am__quote@
@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/errors.Po@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/event-loop.Po@am__quote@
@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/fileio.Po@am__quote@
@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/filestuff.Po@am__quote@
@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/format.Po@am__quote@
--- /dev/null
+/* Event loop machinery for GDB, the GNU debugger.
+ Copyright (C) 1999-2020 Free Software Foundation, Inc.
+ Written by Elena Zannoni <ezannoni@cygnus.com> of Cygnus Solutions.
+
+ This file is part of GDB.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+#include "gdbsupport/common-defs.h"
+#include "gdbsupport/event-loop.h"
+
+#include <chrono>
+
+#ifdef HAVE_POLL
+#if defined (HAVE_POLL_H)
+#include <poll.h>
+#elif defined (HAVE_SYS_POLL_H)
+#include <sys/poll.h>
+#endif
+#endif
+
+#include <sys/types.h>
+#include "gdbsupport/gdb_sys_time.h"
+#include "gdbsupport/gdb_select.h"
+
+/* 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)
+
+/* Information about each file descriptor we register with the event
+ loop. */
+
+typedef struct file_handler
+ {
+ int fd; /* File descriptor. */
+ int mask; /* Events we want to monitor: POLLIN, etc. */
+ int ready_mask; /* Events that have been seen since
+ the last time. */
+ handler_func *proc; /* Procedure to call when fd is ready. */
+ gdb_client_data client_data; /* Argument to pass to proc. */
+ int error; /* Was an error detected on this fd? */
+ struct file_handler *next_file; /* Next registered file descriptor. */
+ }
+file_handler;
+
+/* Gdb_notifier is just a list of file descriptors gdb is interested in.
+ These are the input file descriptor, and the target file
+ descriptor. We have two flavors of the notifier, one for platforms
+ that have the POLL function, the other for those that don't, and
+ only support SELECT. Each of the elements in the gdb_notifier list is
+ basically a description of what kind of events gdb is interested
+ in, for each fd. */
+
+/* As of 1999-04-30 only the input file descriptor is registered with the
+ event loop. */
+
+/* Do we use poll or select ? */
+#ifdef HAVE_POLL
+#define USE_POLL 1
+#else
+#define USE_POLL 0
+#endif /* HAVE_POLL */
+
+static unsigned char use_poll = USE_POLL;
+
+#ifdef USE_WIN32API
+#include <windows.h>
+#include <io.h>
+#endif
+
+static struct
+ {
+ /* Ptr to head of file handler list. */
+ file_handler *first_file_handler;
+
+ /* Next file handler to handle, for the select variant. To level
+ the fairness across event sources, we serve file handlers in a
+ round-robin-like fashion. The number and order of the polled
+ file handlers may change between invocations, but this is good
+ enough. */
+ file_handler *next_file_handler;
+
+#ifdef HAVE_POLL
+ /* Ptr to array of pollfd structures. */
+ struct pollfd *poll_fds;
+
+ /* Next file descriptor to handle, for the poll variant. To level
+ the fairness across event sources, we poll the file descriptors
+ in a round-robin-like fashion. The number and order of the
+ polled file descriptors may change between invocations, but
+ this is good enough. */
+ int next_poll_fds_index;
+
+ /* Timeout in milliseconds for calls to poll(). */
+ int poll_timeout;
+#endif
+
+ /* Masks to be used in the next call to select.
+ Bits are set in response to calls to create_file_handler. */
+ fd_set check_masks[3];
+
+ /* What file descriptors were found ready by select. */
+ fd_set ready_masks[3];
+
+ /* Number of file descriptors to monitor (for poll). */
+ /* Number of valid bits (highest fd value + 1) (for select). */
+ int num_fds;
+
+ /* Time structure for calls to select(). */
+ struct timeval select_timeout;
+
+ /* Flag to tell whether the timeout should be used. */
+ int timeout_valid;
+ }
+gdb_notifier;
+
+/* Structure associated with a timer. PROC will be executed at the
+ first occasion after WHEN. */
+struct gdb_timer
+ {
+ std::chrono::steady_clock::time_point when;
+ int timer_id;
+ struct gdb_timer *next;
+ timer_handler_func *proc; /* Function to call to do the work. */
+ gdb_client_data client_data; /* Argument to async_handler_func. */
+ };
+
+/* List of currently active timers. It is sorted in order of
+ increasing timers. */
+static struct
+ {
+ /* Pointer to first in timer list. */
+ struct gdb_timer *first_timer;
+
+ /* Id of the last timer created. */
+ int num_timers;
+ }
+timer_list;
+
+static void create_file_handler (int fd, int mask, handler_func *proc,
+ gdb_client_data client_data);
+static int gdb_wait_for_event (int);
+static int update_wait_timeout (void);
+static int poll_timers (void);
+\f
+/* Process one high level event. If nothing is ready at this time,
+ wait for something to happen (via gdb_wait_for_event), then process
+ it. Returns >0 if something was done otherwise returns <0 (this
+ can happen if there are no event sources to wait for). */
+
+int
+gdb_do_one_event (void)
+{
+ static int event_source_head = 0;
+ const int number_of_sources = 3;
+ int current = 0;
+
+ /* First let's see if there are any asynchronous signal handlers
+ that are ready. These would be the result of invoking any of the
+ signal handlers. */
+ if (invoke_async_signal_handlers ())
+ return 1;
+
+ /* To level the fairness across event sources, we poll them in a
+ round-robin fashion. */
+ for (current = 0; current < number_of_sources; current++)
+ {
+ int res;
+
+ switch (event_source_head)
+ {
+ case 0:
+ /* Are any timers that are ready? */
+ res = poll_timers ();
+ break;
+ case 1:
+ /* Are there events already waiting to be collected on the
+ monitored file descriptors? */
+ res = gdb_wait_for_event (0);
+ break;
+ case 2:
+ /* Are there any asynchronous event handlers ready? */
+ res = check_async_event_handlers ();
+ break;
+ default:
+ internal_error (__FILE__, __LINE__,
+ "unexpected event_source_head %d",
+ event_source_head);
+ }
+
+ event_source_head++;
+ if (event_source_head == number_of_sources)
+ event_source_head = 0;
+
+ if (res > 0)
+ return 1;
+ }
+
+ /* Block waiting for a new event. If gdb_wait_for_event returns -1,
+ we should get out because this means that there are no event
+ sources left. This will make the event loop stop, and the
+ application exit. */
+
+ if (gdb_wait_for_event (1) < 0)
+ return -1;
+
+ /* If gdb_wait_for_event has returned 1, it means that one event has
+ been handled. We break out of the loop. */
+ return 1;
+}
+
+\f
+
+/* Wrapper function for create_file_handler, so that the caller
+ doesn't have to know implementation details about the use of poll
+ vs. select. */
+void
+add_file_handler (int fd, handler_func * proc, gdb_client_data client_data)
+{
+#ifdef HAVE_POLL
+ struct pollfd fds;
+#endif
+
+ if (use_poll)
+ {
+#ifdef HAVE_POLL
+ /* Check to see if poll () is usable. If not, we'll switch to
+ use select. This can happen on systems like
+ m68k-motorola-sys, `poll' cannot be used to wait for `stdin'.
+ On m68k-motorola-sysv, tty's are not stream-based and not
+ `poll'able. */
+ fds.fd = fd;
+ fds.events = POLLIN;
+ if (poll (&fds, 1, 0) == 1 && (fds.revents & POLLNVAL))
+ use_poll = 0;
+#else
+ internal_error (__FILE__, __LINE__,
+ _("use_poll without HAVE_POLL"));
+#endif /* HAVE_POLL */
+ }
+ if (use_poll)
+ {
+#ifdef HAVE_POLL
+ create_file_handler (fd, POLLIN, proc, client_data);
+#else
+ internal_error (__FILE__, __LINE__,
+ _("use_poll without HAVE_POLL"));
+#endif
+ }
+ else
+ create_file_handler (fd, GDB_READABLE | GDB_EXCEPTION,
+ proc, client_data);
+}
+
+/* Add a file handler/descriptor to the list of descriptors we are
+ interested in.
+
+ FD is the file descriptor for the file/stream to be listened to.
+
+ For the poll case, MASK is a combination (OR) of POLLIN,
+ POLLRDNORM, POLLRDBAND, POLLPRI, POLLOUT, POLLWRNORM, POLLWRBAND:
+ these are the events we are interested in. If any of them occurs,
+ proc should be called.
+
+ For the select case, MASK is a combination of READABLE, WRITABLE,
+ EXCEPTION. PROC is the procedure that will be called when an event
+ occurs for FD. CLIENT_DATA is the argument to pass to PROC. */
+
+static void
+create_file_handler (int fd, int mask, handler_func * proc,
+ gdb_client_data client_data)
+{
+ file_handler *file_ptr;
+
+ /* Do we already have a file handler for this file? (We may be
+ changing its associated procedure). */
+ for (file_ptr = gdb_notifier.first_file_handler; file_ptr != NULL;
+ file_ptr = file_ptr->next_file)
+ {
+ if (file_ptr->fd == fd)
+ break;
+ }
+
+ /* It is a new file descriptor. Add it to the list. Otherwise, just
+ change the data associated with it. */
+ if (file_ptr == NULL)
+ {
+ file_ptr = XNEW (file_handler);
+ file_ptr->fd = fd;
+ file_ptr->ready_mask = 0;
+ file_ptr->next_file = gdb_notifier.first_file_handler;
+ gdb_notifier.first_file_handler = file_ptr;
+
+ if (use_poll)
+ {
+#ifdef HAVE_POLL
+ gdb_notifier.num_fds++;
+ if (gdb_notifier.poll_fds)
+ gdb_notifier.poll_fds =
+ (struct pollfd *) xrealloc (gdb_notifier.poll_fds,
+ (gdb_notifier.num_fds
+ * sizeof (struct pollfd)));
+ else
+ gdb_notifier.poll_fds =
+ XNEW (struct pollfd);
+ (gdb_notifier.poll_fds + gdb_notifier.num_fds - 1)->fd = fd;
+ (gdb_notifier.poll_fds + gdb_notifier.num_fds - 1)->events = mask;
+ (gdb_notifier.poll_fds + gdb_notifier.num_fds - 1)->revents = 0;
+#else
+ internal_error (__FILE__, __LINE__,
+ _("use_poll without HAVE_POLL"));
+#endif /* HAVE_POLL */
+ }
+ else
+ {
+ if (mask & GDB_READABLE)
+ FD_SET (fd, &gdb_notifier.check_masks[0]);
+ else
+ FD_CLR (fd, &gdb_notifier.check_masks[0]);
+
+ if (mask & GDB_WRITABLE)
+ FD_SET (fd, &gdb_notifier.check_masks[1]);
+ else
+ FD_CLR (fd, &gdb_notifier.check_masks[1]);
+
+ if (mask & GDB_EXCEPTION)
+ FD_SET (fd, &gdb_notifier.check_masks[2]);
+ else
+ FD_CLR (fd, &gdb_notifier.check_masks[2]);
+
+ if (gdb_notifier.num_fds <= fd)
+ gdb_notifier.num_fds = fd + 1;
+ }
+ }
+
+ file_ptr->proc = proc;
+ file_ptr->client_data = client_data;
+ file_ptr->mask = mask;
+}
+
+/* Return the next file handler to handle, and advance to the next
+ file handler, wrapping around if the end of the list is
+ reached. */
+
+static file_handler *
+get_next_file_handler_to_handle_and_advance (void)
+{
+ file_handler *curr_next;
+
+ /* The first time around, this is still NULL. */
+ if (gdb_notifier.next_file_handler == NULL)
+ gdb_notifier.next_file_handler = gdb_notifier.first_file_handler;
+
+ curr_next = gdb_notifier.next_file_handler;
+ gdb_assert (curr_next != NULL);
+
+ /* Advance. */
+ gdb_notifier.next_file_handler = curr_next->next_file;
+ /* Wrap around, if necessary. */
+ if (gdb_notifier.next_file_handler == NULL)
+ gdb_notifier.next_file_handler = gdb_notifier.first_file_handler;
+
+ return curr_next;
+}
+
+/* Remove the file descriptor FD from the list of monitored fd's:
+ i.e. we don't care anymore about events on the FD. */
+void
+delete_file_handler (int fd)
+{
+ file_handler *file_ptr, *prev_ptr = NULL;
+ int i;
+#ifdef HAVE_POLL
+ int j;
+ struct pollfd *new_poll_fds;
+#endif
+
+ /* Find the entry for the given file. */
+
+ for (file_ptr = gdb_notifier.first_file_handler; file_ptr != NULL;
+ file_ptr = file_ptr->next_file)
+ {
+ if (file_ptr->fd == fd)
+ break;
+ }
+
+ if (file_ptr == NULL)
+ return;
+
+ if (use_poll)
+ {
+#ifdef HAVE_POLL
+ /* Create a new poll_fds array by copying every fd's information
+ but the one we want to get rid of. */
+
+ new_poll_fds = (struct pollfd *)
+ xmalloc ((gdb_notifier.num_fds - 1) * sizeof (struct pollfd));
+
+ for (i = 0, j = 0; i < gdb_notifier.num_fds; i++)
+ {
+ if ((gdb_notifier.poll_fds + i)->fd != fd)
+ {
+ (new_poll_fds + j)->fd = (gdb_notifier.poll_fds + i)->fd;
+ (new_poll_fds + j)->events = (gdb_notifier.poll_fds + i)->events;
+ (new_poll_fds + j)->revents
+ = (gdb_notifier.poll_fds + i)->revents;
+ j++;
+ }
+ }
+ xfree (gdb_notifier.poll_fds);
+ gdb_notifier.poll_fds = new_poll_fds;
+ gdb_notifier.num_fds--;
+#else
+ internal_error (__FILE__, __LINE__,
+ _("use_poll without HAVE_POLL"));
+#endif /* HAVE_POLL */
+ }
+ else
+ {
+ if (file_ptr->mask & GDB_READABLE)
+ FD_CLR (fd, &gdb_notifier.check_masks[0]);
+ if (file_ptr->mask & GDB_WRITABLE)
+ FD_CLR (fd, &gdb_notifier.check_masks[1]);
+ if (file_ptr->mask & GDB_EXCEPTION)
+ FD_CLR (fd, &gdb_notifier.check_masks[2]);
+
+ /* Find current max fd. */
+
+ if ((fd + 1) == gdb_notifier.num_fds)
+ {
+ gdb_notifier.num_fds--;
+ for (i = gdb_notifier.num_fds; i; i--)
+ {
+ if (FD_ISSET (i - 1, &gdb_notifier.check_masks[0])
+ || FD_ISSET (i - 1, &gdb_notifier.check_masks[1])
+ || FD_ISSET (i - 1, &gdb_notifier.check_masks[2]))
+ break;
+ }
+ gdb_notifier.num_fds = i;
+ }
+ }
+
+ /* Deactivate the file descriptor, by clearing its mask,
+ so that it will not fire again. */
+
+ file_ptr->mask = 0;
+
+ /* If this file handler was going to be the next one to be handled,
+ advance to the next's next, if any. */
+ if (gdb_notifier.next_file_handler == file_ptr)
+ {
+ if (file_ptr->next_file == NULL
+ && file_ptr == gdb_notifier.first_file_handler)
+ gdb_notifier.next_file_handler = NULL;
+ else
+ get_next_file_handler_to_handle_and_advance ();
+ }
+
+ /* Get rid of the file handler in the file handler list. */
+ if (file_ptr == gdb_notifier.first_file_handler)
+ gdb_notifier.first_file_handler = file_ptr->next_file;
+ else
+ {
+ for (prev_ptr = gdb_notifier.first_file_handler;
+ prev_ptr->next_file != file_ptr;
+ prev_ptr = prev_ptr->next_file)
+ ;
+ prev_ptr->next_file = file_ptr->next_file;
+ }
+ xfree (file_ptr);
+}
+
+/* Handle the given event by calling the procedure associated to the
+ corresponding file handler. */
+
+static void
+handle_file_event (file_handler *file_ptr, int ready_mask)
+{
+ int mask;
+#ifdef HAVE_POLL
+ int error_mask;
+#endif
+
+ {
+ {
+ /* With poll, the ready_mask could have any of three events
+ set to 1: POLLHUP, POLLERR, POLLNVAL. These events
+ cannot be used in the requested event mask (events), but
+ they can be returned in the return mask (revents). We
+ need to check for those event too, and add them to the
+ mask which will be passed to the handler. */
+
+ /* See if the desired events (mask) match the received
+ events (ready_mask). */
+
+ if (use_poll)
+ {
+#ifdef HAVE_POLL
+ /* POLLHUP means EOF, but can be combined with POLLIN to
+ signal more data to read. */
+ error_mask = POLLHUP | POLLERR | POLLNVAL;
+ mask = ready_mask & (file_ptr->mask | error_mask);
+
+ if ((mask & (POLLERR | POLLNVAL)) != 0)
+ {
+ /* Work in progress. We may need to tell somebody
+ what kind of error we had. */
+ if (mask & POLLERR)
+ warning (_("Error detected on fd %d"), file_ptr->fd);
+ if (mask & POLLNVAL)
+ warning (_("Invalid or non-`poll'able fd %d"),
+ file_ptr->fd);
+ file_ptr->error = 1;
+ }
+ else
+ file_ptr->error = 0;
+#else
+ internal_error (__FILE__, __LINE__,
+ _("use_poll without HAVE_POLL"));
+#endif /* HAVE_POLL */
+ }
+ else
+ {
+ if (ready_mask & GDB_EXCEPTION)
+ {
+ warning (_("Exception condition detected on fd %d"),
+ file_ptr->fd);
+ file_ptr->error = 1;
+ }
+ else
+ file_ptr->error = 0;
+ mask = ready_mask & file_ptr->mask;
+ }
+
+ /* If there was a match, then call the handler. */
+ if (mask != 0)
+ (*file_ptr->proc) (file_ptr->error, file_ptr->client_data);
+ }
+ }
+}
+
+/* Wait for new events on the monitored file descriptors. Run the
+ event handler if the first descriptor that is detected by the poll.
+ If BLOCK and if there are no events, this function will block in
+ the call to poll. Return 1 if an event was handled. Return -1 if
+ there are no file descriptors to monitor. Return 1 if an event was
+ handled, otherwise returns 0. */
+
+static int
+gdb_wait_for_event (int block)
+{
+ file_handler *file_ptr;
+ int num_found = 0;
+
+ /* Make sure all output is done before getting another event. */
+ flush_streams ();
+
+ if (gdb_notifier.num_fds == 0)
+ return -1;
+
+ if (block)
+ update_wait_timeout ();
+
+ if (use_poll)
+ {
+#ifdef HAVE_POLL
+ int timeout;
+
+ if (block)
+ timeout = gdb_notifier.timeout_valid ? gdb_notifier.poll_timeout : -1;
+ else
+ timeout = 0;
+
+ num_found = poll (gdb_notifier.poll_fds,
+ (unsigned long) gdb_notifier.num_fds, timeout);
+
+ /* Don't print anything if we get out of poll because of a
+ signal. */
+ if (num_found == -1 && errno != EINTR)
+ perror_with_name (("poll"));
+#else
+ internal_error (__FILE__, __LINE__,
+ _("use_poll without HAVE_POLL"));
+#endif /* HAVE_POLL */
+ }
+ else
+ {
+ struct timeval select_timeout;
+ struct timeval *timeout_p;
+
+ if (block)
+ timeout_p = gdb_notifier.timeout_valid
+ ? &gdb_notifier.select_timeout : NULL;
+ else
+ {
+ memset (&select_timeout, 0, sizeof (select_timeout));
+ timeout_p = &select_timeout;
+ }
+
+ gdb_notifier.ready_masks[0] = gdb_notifier.check_masks[0];
+ gdb_notifier.ready_masks[1] = gdb_notifier.check_masks[1];
+ gdb_notifier.ready_masks[2] = gdb_notifier.check_masks[2];
+ num_found = gdb_select (gdb_notifier.num_fds,
+ &gdb_notifier.ready_masks[0],
+ &gdb_notifier.ready_masks[1],
+ &gdb_notifier.ready_masks[2],
+ timeout_p);
+
+ /* Clear the masks after an error from select. */
+ if (num_found == -1)
+ {
+ FD_ZERO (&gdb_notifier.ready_masks[0]);
+ FD_ZERO (&gdb_notifier.ready_masks[1]);
+ FD_ZERO (&gdb_notifier.ready_masks[2]);
+
+ /* Dont print anything if we got a signal, let gdb handle
+ it. */
+ if (errno != EINTR)
+ perror_with_name (("select"));
+ }
+ }
+
+ /* Avoid looking at poll_fds[i]->revents if no event fired. */
+ if (num_found <= 0)
+ return 0;
+
+ /* Run event handlers. We always run just one handler and go back
+ to polling, in case a handler changes the notifier list. Since
+ events for sources we haven't consumed yet wake poll/select
+ immediately, no event is lost. */
+
+ /* To level the fairness across event descriptors, we handle them in
+ a round-robin-like fashion. The number and order of descriptors
+ may change between invocations, but this is good enough. */
+ if (use_poll)
+ {
+#ifdef HAVE_POLL
+ int i;
+ int mask;
+
+ while (1)
+ {
+ if (gdb_notifier.next_poll_fds_index >= gdb_notifier.num_fds)
+ gdb_notifier.next_poll_fds_index = 0;
+ i = gdb_notifier.next_poll_fds_index++;
+
+ gdb_assert (i < gdb_notifier.num_fds);
+ if ((gdb_notifier.poll_fds + i)->revents)
+ break;
+ }
+
+ for (file_ptr = gdb_notifier.first_file_handler;
+ file_ptr != NULL;
+ file_ptr = file_ptr->next_file)
+ {
+ if (file_ptr->fd == (gdb_notifier.poll_fds + i)->fd)
+ break;
+ }
+ gdb_assert (file_ptr != NULL);
+
+ mask = (gdb_notifier.poll_fds + i)->revents;
+ handle_file_event (file_ptr, mask);
+ return 1;
+#else
+ internal_error (__FILE__, __LINE__,
+ _("use_poll without HAVE_POLL"));
+#endif /* HAVE_POLL */
+ }
+ else
+ {
+ /* See comment about even source fairness above. */
+ int mask = 0;
+
+ do
+ {
+ file_ptr = get_next_file_handler_to_handle_and_advance ();
+
+ if (FD_ISSET (file_ptr->fd, &gdb_notifier.ready_masks[0]))
+ mask |= GDB_READABLE;
+ if (FD_ISSET (file_ptr->fd, &gdb_notifier.ready_masks[1]))
+ mask |= GDB_WRITABLE;
+ if (FD_ISSET (file_ptr->fd, &gdb_notifier.ready_masks[2]))
+ mask |= GDB_EXCEPTION;
+ }
+ while (mask == 0);
+
+ handle_file_event (file_ptr, mask);
+ return 1;
+ }
+ return 0;
+}
+\f
+/* Create a timer that will expire in MS milliseconds from now. When
+ the timer is ready, PROC will be executed. At creation, the timer
+ is added to the timers queue. This queue is kept sorted in order
+ of increasing timers. Return a handle to the timer struct. */
+
+int
+create_timer (int ms, timer_handler_func *proc,
+ gdb_client_data client_data)
+{
+ using namespace std::chrono;
+ struct gdb_timer *timer_ptr, *timer_index, *prev_timer;
+
+ steady_clock::time_point time_now = steady_clock::now ();
+
+ timer_ptr = new gdb_timer ();
+ timer_ptr->when = time_now + milliseconds (ms);
+ timer_ptr->proc = proc;
+ timer_ptr->client_data = client_data;
+ timer_list.num_timers++;
+ timer_ptr->timer_id = timer_list.num_timers;
+
+ /* Now add the timer to the timer queue, making sure it is sorted in
+ increasing order of expiration. */
+
+ for (timer_index = timer_list.first_timer;
+ timer_index != NULL;
+ timer_index = timer_index->next)
+ {
+ if (timer_index->when > timer_ptr->when)
+ break;
+ }
+
+ if (timer_index == timer_list.first_timer)
+ {
+ timer_ptr->next = timer_list.first_timer;
+ timer_list.first_timer = timer_ptr;
+
+ }
+ else
+ {
+ for (prev_timer = timer_list.first_timer;
+ prev_timer->next != timer_index;
+ prev_timer = prev_timer->next)
+ ;
+
+ prev_timer->next = timer_ptr;
+ timer_ptr->next = timer_index;
+ }
+
+ gdb_notifier.timeout_valid = 0;
+ return timer_ptr->timer_id;
+}
+
+/* There is a chance that the creator of the timer wants to get rid of
+ it before it expires. */
+void
+delete_timer (int id)
+{
+ struct gdb_timer *timer_ptr, *prev_timer = NULL;
+
+ /* Find the entry for the given timer. */
+
+ for (timer_ptr = timer_list.first_timer; timer_ptr != NULL;
+ timer_ptr = timer_ptr->next)
+ {
+ if (timer_ptr->timer_id == id)
+ break;
+ }
+
+ if (timer_ptr == NULL)
+ return;
+ /* Get rid of the timer in the timer list. */
+ if (timer_ptr == timer_list.first_timer)
+ timer_list.first_timer = timer_ptr->next;
+ else
+ {
+ for (prev_timer = timer_list.first_timer;
+ prev_timer->next != timer_ptr;
+ prev_timer = prev_timer->next)
+ ;
+ prev_timer->next = timer_ptr->next;
+ }
+ delete timer_ptr;
+
+ gdb_notifier.timeout_valid = 0;
+}
+
+/* Convert a std::chrono duration to a struct timeval. */
+
+template<typename Duration>
+static struct timeval
+duration_cast_timeval (const Duration &d)
+{
+ using namespace std::chrono;
+ seconds sec = duration_cast<seconds> (d);
+ microseconds msec = duration_cast<microseconds> (d - sec);
+
+ struct timeval tv;
+ tv.tv_sec = sec.count ();
+ tv.tv_usec = msec.count ();
+ return tv;
+}
+
+/* Update the timeout for the select() or poll(). Returns true if the
+ timer has already expired, false otherwise. */
+
+static int
+update_wait_timeout (void)
+{
+ if (timer_list.first_timer != NULL)
+ {
+ using namespace std::chrono;
+ steady_clock::time_point time_now = steady_clock::now ();
+ struct timeval timeout;
+
+ if (timer_list.first_timer->when < time_now)
+ {
+ /* It expired already. */
+ timeout.tv_sec = 0;
+ timeout.tv_usec = 0;
+ }
+ else
+ {
+ steady_clock::duration d = timer_list.first_timer->when - time_now;
+ timeout = duration_cast_timeval (d);
+ }
+
+ /* Update the timeout for select/ poll. */
+ if (use_poll)
+ {
+#ifdef HAVE_POLL
+ gdb_notifier.poll_timeout = timeout.tv_sec * 1000;
+#else
+ internal_error (__FILE__, __LINE__,
+ _("use_poll without HAVE_POLL"));
+#endif /* HAVE_POLL */
+ }
+ else
+ {
+ gdb_notifier.select_timeout.tv_sec = timeout.tv_sec;
+ gdb_notifier.select_timeout.tv_usec = timeout.tv_usec;
+ }
+ gdb_notifier.timeout_valid = 1;
+
+ if (timer_list.first_timer->when < time_now)
+ return 1;
+ }
+ else
+ gdb_notifier.timeout_valid = 0;
+
+ return 0;
+}
+
+/* Check whether a timer in the timers queue is ready. If a timer is
+ ready, call its handler and return. Update the timeout for the
+ select() or poll() as well. Return 1 if an event was handled,
+ otherwise returns 0.*/
+
+static int
+poll_timers (void)
+{
+ if (update_wait_timeout ())
+ {
+ struct gdb_timer *timer_ptr = timer_list.first_timer;
+ timer_handler_func *proc = timer_ptr->proc;
+ gdb_client_data client_data = timer_ptr->client_data;
+
+ /* Get rid of the timer from the beginning of the list. */
+ timer_list.first_timer = timer_ptr->next;
+
+ /* Delete the timer before calling the callback, not after, in
+ case the callback itself decides to try deleting the timer
+ too. */
+ delete timer_ptr;
+
+ /* Call the procedure associated with that timer. */
+ (proc) (client_data);
+
+ return 1;
+ }
+
+ return 0;
+}
--- /dev/null
+/* Definitions used by the GDB event loop.
+ Copyright (C) 1999-2020 Free Software Foundation, Inc.
+ Written by Elena Zannoni <ezannoni@cygnus.com> of Cygnus Solutions.
+
+ This file is part of GDB.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+#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
+ sources to listen on. External event sources can be plugged into
+ the loop.
+
+ 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 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
+ event is represented by a procedure to be invoked in order to
+ process the event. The queue is scanned head to tail. If the
+ event of interest is a change of state in a file descriptor, then a
+ call to poll or select will be made to detect it.
+
+ If the events generate signals, they are also queued by special
+ 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.
+
+ Corollary tasks are the creation and deletion of event sources. */
+
+typedef void *gdb_client_data;
+typedef void (handler_func) (int, gdb_client_data);
+typedef void (timer_handler_func) (gdb_client_data);
+
+/* Exported functions from event-loop.c */
+
+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 int create_timer (int milliseconds,
+ timer_handler_func *proc,
+ gdb_client_data client_data);
+extern void delete_timer (int id);
+
+/* Must be defined by client. */
+
+extern void handle_event_loop_exception (const gdb_exception &);
+
+/* Must be defined by client. Returns true if any signal handler was
+ ready. */
+
+extern int invoke_async_signal_handlers ();
+
+/* Must be defined by client. Returns true if any event handler was
+ ready. */
+
+extern int check_async_event_handlers ();
+
+#endif /* EVENT_LOOP_H */
projects / deliverable / binutils-gdb.git / commitdiff
