/* Event loop machinery for GDB, the GNU debugger. Copyright (C) 1999-2019 Free Software Foundation, Inc. Written by Elena Zannoni 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 . */ #include "defs.h" #include "event-loop.h" #include "event-top.h" #include "ser-event.h" #ifdef HAVE_POLL #if defined (HAVE_POLL_H) #include #elif defined (HAVE_SYS_POLL_H) #include #endif #endif #include #include "common/gdb_sys_time.h" #include "gdb_select.h" #include "observable.h" #include "top.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) /* Data point to pass to the event handler. */ typedef union event_data { void *ptr; int integer; } event_data; typedef struct gdb_event gdb_event; typedef void (event_handler_func) (event_data); /* Event for the GDB event system. Events are queued by calling async_queue_event and serviced later on by gdb_do_one_event. An event can be, for instance, a file descriptor becoming ready to be read. Servicing an event simply means that the procedure PROC will be called. We have 2 queues, one for file handlers that we listen to in the event loop, and one for the file handlers+events that are ready. The procedure PROC associated with each event is dependant of the event source. In the case of monitored file descriptors, it is always the same (handle_file_event). Its duty is to invoke the handler associated with the file descriptor whose state change generated the event, plus doing other cleanups and such. In the case of async signal handlers, it is invoke_async_signal_handler. */ typedef struct gdb_event { /* Procedure to call to service this event. */ event_handler_func *proc; /* Data to pass to the event handler. */ event_data data; } *gdb_event_p; /* 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; /* PROC is a function to be invoked when the READY flag is set. This happens when there has been a signal and the corresponding signal handler has 'triggered' this async_signal_handler for execution. The actual work to be done in response to a signal will be carried out by PROC at a later time, within process_event. This provides a deferred execution of signal handlers. Async_init_signals takes care of setting up such an async_signal_handler for each interesting signal. */ typedef struct async_signal_handler { int ready; /* If ready, call this handler from the main event loop, using invoke_async_handler. */ struct async_signal_handler *next_handler; /* Ptr to next handler. */ sig_handler_func *proc; /* Function to call to do the work. */ gdb_client_data client_data; /* Argument to async_handler_func. */ } async_signal_handler; /* PROC is a function to be invoked when the READY flag is set. This happens when the event has been marked with MARK_ASYNC_EVENT_HANDLER. The actual work to be done in response to an event will be carried out by PROC at a later time, within process_event. This provides a deferred execution of event handlers. */ typedef struct async_event_handler { /* If ready, call this handler from the main event loop, using invoke_event_handler. */ int ready; /* Point to next handler. */ struct async_event_handler *next_handler; /* Function to call to do the work. */ async_event_handler_func *proc; /* Argument to PROC. */ gdb_client_data client_data; } async_event_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 #include #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; /* All the async_signal_handlers gdb is interested in are kept onto this list. */ static struct { /* Pointer to first in handler list. */ async_signal_handler *first_handler; /* Pointer to last in handler list. */ async_signal_handler *last_handler; } sighandler_list; /* All the async_event_handlers gdb is interested in are kept onto this list. */ static struct { /* Pointer to first in handler list. */ async_event_handler *first_handler; /* Pointer to last in handler list. */ async_event_handler *last_handler; } async_event_handler_list; static int invoke_async_signal_handlers (void); static void create_file_handler (int fd, int mask, handler_func *proc, gdb_client_data client_data); static int check_async_event_handlers (void); static int gdb_wait_for_event (int); static int update_wait_timeout (void); static int poll_timers (void); /* This event is signalled whenever an asynchronous handler needs to defer an action to the event loop. */ static struct serial_event *async_signal_handlers_serial_event; /* Callback registered with ASYNC_SIGNAL_HANDLERS_SERIAL_EVENT. */ static void async_signals_handler (int error, gdb_client_data client_data) { /* Do nothing. Handlers are run by invoke_async_signal_handlers from instead. */ } void initialize_async_signal_handlers (void) { async_signal_handlers_serial_event = make_serial_event (); add_file_handler (serial_event_fd (async_signal_handlers_serial_event), async_signals_handler, NULL); } /* 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; } /* Start up the event loop. This is the entry point to the event loop from the command loop. */ void start_event_loop (void) { /* Loop until there is nothing to do. This is the entry point to the event loop engine. gdb_do_one_event will process one event for each invocation. It blocks waiting for an event and then processes it. */ while (1) { int result = 0; try { result = gdb_do_one_event (); } catch (const gdb_exception &ex) { exception_print (gdb_stderr, ex); /* If any exception escaped to here, we better enable stdin. Otherwise, any command that calls async_disable_stdin, and then throws, will leave stdin inoperable. */ async_enable_stdin (); /* If we long-jumped out of do_one_event, we probably didn't get around to resetting the prompt, which leaves readline in a messed-up state. Reset it here. */ current_ui->prompt_state = PROMPT_NEEDED; gdb::observers::command_error.notify (); /* This call looks bizarre, but it is required. If the user entered a command that caused an error, after_char_processing_hook won't be called from rl_callback_read_char_wrapper. Using a cleanup there won't work, since we want this function to be called after a new prompt is printed. */ if (after_char_processing_hook) (*after_char_processing_hook) (); /* Maybe better to set a flag to be checked somewhere as to whether display the prompt or not. */ } if (result < 0) break; } /* We are done with the event loop. There are no more event sources to listen to. So we exit GDB. */ return; } /* 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) printf_unfiltered (_("Error detected on fd %d\n"), file_ptr->fd); if (mask & POLLNVAL) printf_unfiltered (_("Invalid or non-`poll'able fd %d\n"), 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) { printf_unfiltered (_("Exception condition detected " "on fd %d\n"), 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. */ gdb_flush (gdb_stdout); gdb_flush (gdb_stderr); 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; } /* Create an asynchronous handler, allocating memory for it. Return a pointer to the newly created handler. This pointer will be used to invoke the handler by invoke_async_signal_handler. PROC is the function to call with CLIENT_DATA argument whenever the handler is invoked. */ async_signal_handler * create_async_signal_handler (sig_handler_func * proc, gdb_client_data client_data) { async_signal_handler *async_handler_ptr; async_handler_ptr = XNEW (async_signal_handler); async_handler_ptr->ready = 0; async_handler_ptr->next_handler = NULL; async_handler_ptr->proc = proc; async_handler_ptr->client_data = client_data; if (sighandler_list.first_handler == NULL) sighandler_list.first_handler = async_handler_ptr; else sighandler_list.last_handler->next_handler = async_handler_ptr; sighandler_list.last_handler = async_handler_ptr; return async_handler_ptr; } /* Mark the handler (ASYNC_HANDLER_PTR) as ready. This information will be used when the handlers are invoked, after we have waited for some event. The caller of this function is the interrupt handler associated with a signal. */ void mark_async_signal_handler (async_signal_handler * async_handler_ptr) { async_handler_ptr->ready = 1; serial_event_set (async_signal_handlers_serial_event); } /* See event-loop.h. */ void clear_async_signal_handler (async_signal_handler *async_handler_ptr) { async_handler_ptr->ready = 0; } /* See event-loop.h. */ int async_signal_handler_is_marked (async_signal_handler *async_handler_ptr) { return async_handler_ptr->ready; } /* Call all the handlers that are ready. Returns true if any was indeed ready. */ static int invoke_async_signal_handlers (void) { async_signal_handler *async_handler_ptr; int any_ready = 0; /* We're going to handle all pending signals, so no need to wake up the event loop again the next time around. Note this must be cleared _before_ calling the callbacks, to avoid races. */ serial_event_clear (async_signal_handlers_serial_event); /* Invoke all ready handlers. */ while (1) { for (async_handler_ptr = sighandler_list.first_handler; async_handler_ptr != NULL; async_handler_ptr = async_handler_ptr->next_handler) { if (async_handler_ptr->ready) break; } if (async_handler_ptr == NULL) break; any_ready = 1; async_handler_ptr->ready = 0; /* Async signal handlers have no connection to whichever was the current UI, and thus always run on the main one. */ current_ui = main_ui; (*async_handler_ptr->proc) (async_handler_ptr->client_data); } return any_ready; } /* Delete an asynchronous handler (ASYNC_HANDLER_PTR). Free the space allocated for it. */ void delete_async_signal_handler (async_signal_handler ** async_handler_ptr) { async_signal_handler *prev_ptr; if (sighandler_list.first_handler == (*async_handler_ptr)) { sighandler_list.first_handler = (*async_handler_ptr)->next_handler; if (sighandler_list.first_handler == NULL) sighandler_list.last_handler = NULL; } else { prev_ptr = sighandler_list.first_handler; while (prev_ptr && prev_ptr->next_handler != (*async_handler_ptr)) prev_ptr = prev_ptr->next_handler; gdb_assert (prev_ptr); prev_ptr->next_handler = (*async_handler_ptr)->next_handler; if (sighandler_list.last_handler == (*async_handler_ptr)) sighandler_list.last_handler = prev_ptr; } xfree ((*async_handler_ptr)); (*async_handler_ptr) = NULL; } /* Create an asynchronous event handler, allocating memory for it. Return a pointer to the newly created handler. PROC is the function to call with CLIENT_DATA argument whenever the handler is invoked. */ async_event_handler * create_async_event_handler (async_event_handler_func *proc, gdb_client_data client_data) { async_event_handler *h; h = XNEW (struct async_event_handler); h->ready = 0; h->next_handler = NULL; h->proc = proc; h->client_data = client_data; if (async_event_handler_list.first_handler == NULL) async_event_handler_list.first_handler = h; else async_event_handler_list.last_handler->next_handler = h; async_event_handler_list.last_handler = h; return h; } /* Mark the handler (ASYNC_HANDLER_PTR) as ready. This information will be used by gdb_do_one_event. The caller will be whoever created the event source, and wants to signal that the event is ready to be handled. */ void mark_async_event_handler (async_event_handler *async_handler_ptr) { async_handler_ptr->ready = 1; } /* See event-loop.h. */ void clear_async_event_handler (async_event_handler *async_handler_ptr) { async_handler_ptr->ready = 0; } /* Check if asynchronous event handlers are ready, and call the handler function for one that is. */ static int check_async_event_handlers (void) { async_event_handler *async_handler_ptr; for (async_handler_ptr = async_event_handler_list.first_handler; async_handler_ptr != NULL; async_handler_ptr = async_handler_ptr->next_handler) { if (async_handler_ptr->ready) { async_handler_ptr->ready = 0; (*async_handler_ptr->proc) (async_handler_ptr->client_data); return 1; } } return 0; } /* Delete an asynchronous handler (ASYNC_HANDLER_PTR). Free the space allocated for it. */ void delete_async_event_handler (async_event_handler **async_handler_ptr) { async_event_handler *prev_ptr; if (async_event_handler_list.first_handler == *async_handler_ptr) { async_event_handler_list.first_handler = (*async_handler_ptr)->next_handler; if (async_event_handler_list.first_handler == NULL) async_event_handler_list.last_handler = NULL; } else { prev_ptr = async_event_handler_list.first_handler; while (prev_ptr && prev_ptr->next_handler != *async_handler_ptr) prev_ptr = prev_ptr->next_handler; gdb_assert (prev_ptr); prev_ptr->next_handler = (*async_handler_ptr)->next_handler; if (async_event_handler_list.last_handler == (*async_handler_ptr)) async_event_handler_list.last_handler = prev_ptr; } xfree (*async_handler_ptr); *async_handler_ptr = NULL; } /* 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 static struct timeval duration_cast_timeval (const Duration &d) { using namespace std::chrono; seconds sec = duration_cast (d); microseconds msec = duration_cast (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; }