/* Event loop machinery for GDB, the GNU debugger. Copyright (C) 1999, 2000, 2001, 2002, 2005, 2006, 2007, 2008, 2009, 2010 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 "event-top.h" #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 "gdb_string.h" #include <errno.h> #include <sys/time.h> #include "exceptions.h" #include "gdb_assert.h" #include "gdb_select.h" /* 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. */ struct gdb_event { /* Procedure to call to service this event. */ event_handler_func *proc; /* Data to pass to the event handler. */ event_data data; /* Next in list of events or NULL. */ struct gdb_event *next_event; }; /* 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; /* Event queue: - the first event in the queue is the head of the queue. It will be the next to be serviced. - the last event in the queue Events can be inserted at the front of the queue or at the end of the queue. Events will be extracted from the queue for processing starting from the head. Therefore, events inserted at the head of the queue will be processed in a last in first out fashion, while those inserted at the tail of the queue will be processed in a first in first out manner. All the fields are NULL if the queue is empty. */ static struct { gdb_event *first_event; /* First pending event */ gdb_event *last_event; /* Last pending event */ } event_queue; /* 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; #ifdef HAVE_POLL /* Ptr to array of pollfd structures. */ struct pollfd *poll_fds; /* 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 { struct timeval 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 */ } gdb_timer; /* 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 void handle_file_event (event_data data); static void check_async_event_handlers (void); static int gdb_wait_for_event (int); static void poll_timers (void); /* Insert an event object into the gdb event queue at the specified position. POSITION can be head or tail, with values TAIL, HEAD. EVENT_PTR points to the event to be inserted into the queue. The caller must allocate memory for the event. It is freed after the event has ben handled. Events in the queue will be processed head to tail, therefore, events inserted at the head of the queue will be processed as last in first out. Event appended at the tail of the queue will be processed first in first out. */ static void async_queue_event (gdb_event * event_ptr, queue_position position) { if (position == TAIL) { /* The event will become the new last_event. */ event_ptr->next_event = NULL; if (event_queue.first_event == NULL) event_queue.first_event = event_ptr; else event_queue.last_event->next_event = event_ptr; event_queue.last_event = event_ptr; } else if (position == HEAD) { /* The event becomes the new first_event. */ event_ptr->next_event = event_queue.first_event; if (event_queue.first_event == NULL) event_queue.last_event = event_ptr; event_queue.first_event = event_ptr; } } /* Create a generic event, to be enqueued in the event queue for processing. PROC is the procedure associated to the event. DATA is passed to PROC upon PROC invocation. */ static gdb_event * create_event (event_handler_func proc, event_data data) { gdb_event *event; event = xmalloc (sizeof (*event)); event->proc = proc; event->data = data; return event; } /* Create a file event, to be enqueued in the event queue for processing. The procedure associated to this event is always handle_file_event, which will in turn invoke the one that was associated to FD when it was registered with the event loop. */ static gdb_event * create_file_event (int fd) { event_data data; data.integer = fd; return create_event (handle_file_event, data); } /* Process one event. The event can be the next one to be serviced in the event queue, or an asynchronous event handler can be invoked in response to the reception of a signal. If an event was processed (either way), 1 is returned otherwise 0 is returned. Scan the queue from head to tail, processing therefore the high priority events first, by invoking the associated event handler procedure. */ static int process_event (void) { gdb_event *event_ptr, *prev_ptr; event_handler_func *proc; event_data data; /* First let's see if there are any asynchronous event handlers that are ready. These would be the result of invoking any of the signal handlers. */ if (invoke_async_signal_handlers ()) return 1; /* Look in the event queue to find an event that is ready to be processed. */ for (event_ptr = event_queue.first_event; event_ptr != NULL; event_ptr = event_ptr->next_event) { /* Call the handler for the event. */ proc = event_ptr->proc; data = event_ptr->data; /* Let's get rid of the event from the event queue. We need to do this now because while processing the event, the proc function could end up calling 'error' and therefore jump out to the caller of this function, gdb_do_one_event. In that case, we would have on the event queue an event wich has been processed, but not deleted. */ if (event_queue.first_event == event_ptr) { event_queue.first_event = event_ptr->next_event; if (event_ptr->next_event == NULL) event_queue.last_event = NULL; } else { prev_ptr = event_queue.first_event; while (prev_ptr->next_event != event_ptr) prev_ptr = prev_ptr->next_event; prev_ptr->next_event = event_ptr->next_event; if (event_ptr->next_event == NULL) event_queue.last_event = prev_ptr; } xfree (event_ptr); /* Now call the procedure associated with the event. */ (*proc) (data); return 1; } /* this is the case if there are no event on the event queue. */ return 0; } /* 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). If an error occurs catch_errors() which calls this function returns zero. */ int gdb_do_one_event (void *data) { static int event_source_head = 0; const int number_of_sources = 3; int current = 0; /* Any events already waiting in the queue? */ if (process_event ()) 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++) { switch (event_source_head) { case 0: /* Are any timers that are ready? If so, put an event on the queue. */ poll_timers (); break; case 1: /* Are there events already waiting to be collected on the monitored file descriptors? */ gdb_wait_for_event (0); break; case 2: /* Are there any asynchronous event handlers ready? */ check_async_event_handlers (); break; } event_source_head++; if (event_source_head == number_of_sources) event_source_head = 0; } /* Handle any new events collected. */ if (process_event ()) 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; /* Handle any new events occurred while waiting. */ if (process_event ()) 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, called via catch_errors() will process one event for each invocation. It blocks waits for an event and then processes it. >0 when an event is processed, 0 when catch_errors() caught an error and <0 when there are no longer any event sources registered. */ while (1) { int gdb_result; gdb_result = catch_errors (gdb_do_one_event, 0, "", RETURN_MASK_ALL); if (gdb_result < 0) break; /* 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. */ if (gdb_result == 0) { /* 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 (); /* FIXME: this should really be a call to a hook that is interface specific, because interfaces can display the prompt in their own way. */ display_gdb_prompt (0); /* 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. */ } } /* 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 = (file_handler *) xmalloc (sizeof (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 = (struct pollfd *) xmalloc (sizeof (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; } /* 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; /* 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. Called by process_event indirectly, through event_ptr->proc. EVENT_FILE_DESC is file descriptor of the event in the front of the event queue. */ static void handle_file_event (event_data data) { file_handler *file_ptr; int mask; #ifdef HAVE_POLL int error_mask; int error_mask_returned; #endif int event_file_desc = data.integer; /* Search the file handler list to find one that matches the fd in the event. */ for (file_ptr = gdb_notifier.first_file_handler; file_ptr != NULL; file_ptr = file_ptr->next_file) { if (file_ptr->fd == event_file_desc) { /* 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 error_mask = POLLHUP | POLLERR | POLLNVAL; mask = (file_ptr->ready_mask & file_ptr->mask) | (file_ptr->ready_mask & error_mask); error_mask_returned = mask & error_mask; if (error_mask_returned != 0) { /* Work in progress. We may need to tell somebody what kind of error we had. */ if (error_mask_returned & POLLHUP) printf_unfiltered (_("Hangup detected on fd %d\n"), file_ptr->fd); if (error_mask_returned & POLLERR) printf_unfiltered (_("Error detected on fd %d\n"), file_ptr->fd); if (error_mask_returned & 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 (file_ptr->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 = file_ptr->ready_mask & file_ptr->mask; } /* Clear the received events for next time around. */ file_ptr->ready_mask = 0; /* If there was a match, then call the handler. */ if (mask != 0) (*file_ptr->proc) (file_ptr->error, file_ptr->client_data); break; } } } /* Called by gdb_do_one_event to wait for new events on the monitored file descriptors. Queue file events as they are detected by the poll. If BLOCK and if there are no events, this function will block in the call to poll. Return -1 if there are no files descriptors to monitor, otherwise return 0. */ static int gdb_wait_for_event (int block) { file_handler *file_ptr; gdb_event *file_event_ptr; int num_found = 0; int i; /* 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 (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")); } } /* Enqueue all detected file events. */ if (use_poll) { #ifdef HAVE_POLL for (i = 0; (i < gdb_notifier.num_fds) && (num_found > 0); i++) { if ((gdb_notifier.poll_fds + i)->revents) num_found--; else continue; 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; } if (file_ptr) { /* Enqueue an event only if this is still a new event for this fd. */ if (file_ptr->ready_mask == 0) { file_event_ptr = create_file_event (file_ptr->fd); async_queue_event (file_event_ptr, TAIL); } file_ptr->ready_mask = (gdb_notifier.poll_fds + i)->revents; } } #else internal_error (__FILE__, __LINE__, _("use_poll without HAVE_POLL")); #endif /* HAVE_POLL */ } else { for (file_ptr = gdb_notifier.first_file_handler; (file_ptr != NULL) && (num_found > 0); file_ptr = file_ptr->next_file) { int mask = 0; 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; if (!mask) continue; else num_found--; /* Enqueue an event only if this is still a new event for this fd. */ if (file_ptr->ready_mask == 0) { file_event_ptr = create_file_event (file_ptr->fd); async_queue_event (file_event_ptr, TAIL); } file_ptr->ready_mask = mask; } } 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 = (async_signal_handler *) xmalloc (sizeof (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; } /* Call the handler from HANDLER immediately. This function runs signal handlers when returning to the event loop would be too slow. */ void call_async_signal_handler (struct async_signal_handler *handler) { (*handler->proc) (handler->client_data); } /* 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; } /* 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; /* Invoke 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_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; 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 = xmalloc (sizeof (*h)); 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; } struct async_event_handler_data { async_event_handler_func* proc; gdb_client_data client_data; }; static void invoke_async_event_handler (event_data data) { struct async_event_handler_data *hdata = data.ptr; async_event_handler_func* proc = hdata->proc; gdb_client_data client_data = hdata->client_data; xfree (hdata); (*proc) (client_data); } /* Check if any asynchronous event handlers are ready, and queue events in the ready queue for any that are. */ static void check_async_event_handlers (void) { async_event_handler *async_handler_ptr; struct async_event_handler_data *hdata; struct gdb_event *event_ptr; event_data data; 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; hdata = xmalloc (sizeof (*hdata)); hdata->proc = async_handler_ptr->proc; hdata->client_data = async_handler_ptr->client_data; data.ptr = hdata; event_ptr = create_event (invoke_async_event_handler, data); async_queue_event (event_ptr, TAIL); } } } /* 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; 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 MILLISECONDS from now. When the timer is ready, PROC will be executed. At creation, the timer is aded 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 milliseconds, timer_handler_func * proc, gdb_client_data client_data) { struct gdb_timer *timer_ptr, *timer_index, *prev_timer; struct timeval time_now, delta; /* compute seconds */ delta.tv_sec = milliseconds / 1000; /* compute microseconds */ delta.tv_usec = (milliseconds % 1000) * 1000; gettimeofday (&time_now, NULL); timer_ptr = (struct gdb_timer *) xmalloc (sizeof (gdb_timer)); timer_ptr->when.tv_sec = time_now.tv_sec + delta.tv_sec; timer_ptr->when.tv_usec = time_now.tv_usec + delta.tv_usec; /* carry? */ if (timer_ptr->when.tv_usec >= 1000000) { timer_ptr->when.tv_sec += 1; timer_ptr->when.tv_usec -= 1000000; } 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 the seconds field is greater or if it is the same, but the microsecond field is greater. */ if ((timer_index->when.tv_sec > timer_ptr->when.tv_sec) || ((timer_index->when.tv_sec == timer_ptr->when.tv_sec) && (timer_index->when.tv_usec > timer_ptr->when.tv_usec))) 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; } xfree (timer_ptr); gdb_notifier.timeout_valid = 0; } /* When a timer event is put on the event queue, it will be handled by this function. Just call the associated procedure and delete the timer event from the event queue. Repeat this for each timer that has expired. */ static void handle_timer_event (event_data dummy) { struct timeval time_now; struct gdb_timer *timer_ptr, *saved_timer; gettimeofday (&time_now, NULL); timer_ptr = timer_list.first_timer; while (timer_ptr != NULL) { if ((timer_ptr->when.tv_sec > time_now.tv_sec) || ((timer_ptr->when.tv_sec == time_now.tv_sec) && (timer_ptr->when.tv_usec > time_now.tv_usec))) break; /* Get rid of the timer from the beginning of the list. */ timer_list.first_timer = timer_ptr->next; saved_timer = timer_ptr; timer_ptr = timer_ptr->next; /* Call the procedure associated with that timer. */ (*saved_timer->proc) (saved_timer->client_data); xfree (saved_timer); } gdb_notifier.timeout_valid = 0; } /* Check whether any timers in the timers queue are ready. If at least one timer is ready, stick an event onto the event queue. Even in case more than one timer is ready, one event is enough, because the handle_timer_event() will go through the timers list and call the procedures associated with all that have expired. Update the timeout for the select() or poll() as well. */ static void poll_timers (void) { struct timeval time_now, delta; gdb_event *event_ptr; if (timer_list.first_timer != NULL) { gettimeofday (&time_now, NULL); delta.tv_sec = timer_list.first_timer->when.tv_sec - time_now.tv_sec; delta.tv_usec = timer_list.first_timer->when.tv_usec - time_now.tv_usec; /* borrow? */ if (delta.tv_usec < 0) { delta.tv_sec -= 1; delta.tv_usec += 1000000; } /* Oops it expired already. Tell select / poll to return immediately. (Cannot simply test if delta.tv_sec is negative because time_t might be unsigned.) */ if (timer_list.first_timer->when.tv_sec < time_now.tv_sec || (timer_list.first_timer->when.tv_sec == time_now.tv_sec && timer_list.first_timer->when.tv_usec < time_now.tv_usec)) { delta.tv_sec = 0; delta.tv_usec = 0; } if (delta.tv_sec == 0 && delta.tv_usec == 0) { event_ptr = (gdb_event *) xmalloc (sizeof (gdb_event)); event_ptr->proc = handle_timer_event; event_ptr->data.integer = timer_list.first_timer->timer_id; async_queue_event (event_ptr, TAIL); } /* Now we need to update the timeout for select/ poll, because we don't want to sit there while this timer is expiring. */ if (use_poll) { #ifdef HAVE_POLL gdb_notifier.poll_timeout = delta.tv_sec * 1000; #else internal_error (__FILE__, __LINE__, _("use_poll without HAVE_POLL")); #endif /* HAVE_POLL */ } else { gdb_notifier.select_timeout.tv_sec = delta.tv_sec; gdb_notifier.select_timeout.tv_usec = delta.tv_usec; } gdb_notifier.timeout_valid = 1; } else gdb_notifier.timeout_valid = 0; }