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Diffstat (limited to 'contrib/gdb/gdb/event-loop.c')
| -rw-r--r-- | contrib/gdb/gdb/event-loop.c | 1151 |
1 files changed, 1151 insertions, 0 deletions
diff --git a/contrib/gdb/gdb/event-loop.c b/contrib/gdb/gdb/event-loop.c new file mode 100644 index 0000000..ea74419 --- /dev/null +++ b/contrib/gdb/gdb/event-loop.c @@ -0,0 +1,1151 @@ +/* Event loop machinery for GDB, the GNU debugger. + Copyright 1999, 2000, 2001 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 2 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, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +#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> + +typedef struct gdb_event gdb_event; +typedef void (event_handler_func) (int); + +/* 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 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. */ + +struct gdb_event + { + event_handler_func *proc; /* Procedure to call to service this event. */ + int fd; /* File descriptor that is ready. */ + struct gdb_event *next_event; /* Next in list of events or NULL. */ + }; + +/* 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 + asyn_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; + + +/* 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; + +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; + +/* Are any of the handlers ready? Check this variable using + check_async_ready. This is used by process_event, to determine + whether or not to invoke the invoke_async_signal_handler + function. */ +static int async_handler_ready = 0; + +static void create_file_handler (int fd, int mask, handler_func * proc, gdb_client_data client_data); +static void invoke_async_signal_handler (void); +static void handle_file_event (int event_file_desc); +static int gdb_wait_for_event (void); +static int gdb_do_one_event (void *data); +static int check_async_ready (void); +static void async_queue_event (gdb_event * event_ptr, queue_position position); +static gdb_event *create_file_event (int fd); +static int process_event (void); +static void handle_timer_event (int dummy); +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 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) +{ + gdb_event *file_event_ptr; + + file_event_ptr = (gdb_event *) xmalloc (sizeof (gdb_event)); + file_event_ptr->proc = handle_file_event; + file_event_ptr->fd = fd; + return (file_event_ptr); +} + +/* 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; + int fd; + + /* 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 (check_async_ready ()) + { + invoke_async_signal_handler (); + 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; + fd = event_ptr->fd; + + /* 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) (fd); + 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. */ + +static int +gdb_do_one_event (void *data) +{ + /* Any events already waiting in the queue? */ + if (process_event ()) + { + return 1; + } + + /* Are any timers that are ready? If so, put an event on the queue. */ + poll_timers (); + + /* Wait 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 () < 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 result = catch_errors (gdb_do_one_event, 0, "", RETURN_MASK_ALL); + if (result < 0) + break; + if (result == 0) + { + /* 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; + } + file_ptr->proc = proc; + file_ptr->client_data = client_data; + file_ptr->mask = mask; + + 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; + } +} + +/* 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 (int event_file_desc) +{ + file_handler *file_ptr; + int mask; +#ifdef HAVE_POLL + int error_mask; + int error_mask_returned; +#endif + + /* 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 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 (void) +{ + 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 + num_found = + poll (gdb_notifier.poll_fds, + (unsigned long) gdb_notifier.num_fds, + gdb_notifier.timeout_valid ? gdb_notifier.poll_timeout : -1); + + /* 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 + { + 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 = select (gdb_notifier.num_fds, + &gdb_notifier.ready_masks[0], + &gdb_notifier.ready_masks[1], + &gdb_notifier.ready_masks[2], + gdb_notifier.timeout_valid + ? &gdb_notifier.select_timeout : NULL); + + /* 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 is 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; +} + +/* 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_signal_handler *) async_handler_ptr)->ready = 1; + async_handler_ready = 1; +} + +/* Call all the handlers that are ready. */ +static void +invoke_async_signal_handler (void) +{ + async_signal_handler *async_handler_ptr; + + if (async_handler_ready == 0) + return; + async_handler_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; + async_handler_ptr->ready = 0; + (*async_handler_ptr->proc) (async_handler_ptr->client_data); + } + + return; +} + +/* 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->next_handler != (*async_handler_ptr) && prev_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; +} + +/* Is it necessary to call invoke_async_signal_handler? */ +static int +check_async_ready (void) +{ + return async_handler_ready; +} + +/* 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 assiciated procedure and delete the + timer event from the event queue. Repeat this for each timer that + has expired. */ +static void +handle_timer_event (int 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->fd = 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; +} |
