X-Git-Url: http://drtracing.org/?a=blobdiff_plain;f=gdb%2Fevent-loop.c;h=7934ab4c82f8276058576bdf7c71d616fa817f8f;hb=e2882c85786571175a0b0bfc3bcd2f14620b1ea3;hp=afbc2d70ea66a2640a63b41564f0f68bc4c3348e;hpb=905e0470f48bf087826c6779f0140f148e03c13a;p=deliverable%2Fbinutils-gdb.git diff --git a/gdb/event-loop.c b/gdb/event-loop.c index afbc2d70ea..7934ab4c82 100644 --- a/gdb/event-loop.c +++ b/gdb/event-loop.c @@ -1,6 +1,5 @@ /* Event loop machinery for GDB, the GNU debugger. - Copyright (C) 1999, 2000, 2001, 2002, 2005, 2006, 2007, 2008, 2009 - Free Software Foundation, Inc. + Copyright (C) 1999-2018 Free Software Foundation, Inc. Written by Elena Zannoni of Cygnus Solutions. This file is part of GDB. @@ -16,11 +15,13 @@ 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 . */ + along with this program. If not, see . */ #include "defs.h" #include "event-loop.h" #include "event-top.h" +#include "queue.h" +#include "ser-event.h" #ifdef HAVE_POLL #if defined (HAVE_POLL_H) @@ -31,12 +32,17 @@ #endif #include -#include "gdb_string.h" -#include -#include -#include "exceptions.h" -#include "gdb_assert.h" +#include "gdb_sys_time.h" #include "gdb_select.h" +#include "observer.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 @@ -49,12 +55,12 @@ 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 + 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 + 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 @@ -62,49 +68,49 @@ typedef void (event_handler_func) (event_data); case of async signal handlers, it is invoke_async_signal_handler. */ -struct gdb_event +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; - - /* Next in list of events or NULL. */ - struct gdb_event *next_event; - }; + } *gdb_event_p; /* Information about each file descriptor we register with the event - loop. */ + loop. */ typedef struct file_handler { - int fd; /* File descriptor. */ - int mask; /* Events we want to monitor: POLLIN, etc. */ + 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. */ + 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 +/* 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. + 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. */ + 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 */ + 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; @@ -131,37 +137,16 @@ typedef struct async_event_handler } 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 + 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 + 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. */ + in, for each fd. */ /* As of 1999-04-30 only the input file descriptor is registered with the - event loop. */ + event loop. */ /* Do we use poll or select ? */ #ifdef HAVE_POLL @@ -179,80 +164,93 @@ static unsigned char use_poll = USE_POLL; static struct { - /* Ptr to head of file handler list. */ + /* 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. */ + /* Ptr to array of pollfd structures. */ struct pollfd *poll_fds; - /* Timeout in milliseconds for calls to poll(). */ + /* 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. */ + Bits are set in response to calls to create_file_handler. */ fd_set check_masks[3]; - /* What file descriptors were found ready by select. */ + /* 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) */ + /* 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(). */ + /* Time structure for calls to select(). */ struct timeval select_timeout; - /* Flag to tell whether the timeout should be used. */ + /* 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. */ +/* Structure associated with a timer. PROC will be executed at the + first occasion after WHEN. */ struct gdb_timer { - struct timeval when; + 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 */ - } -gdb_timer; + 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. */ +/* List of currently active timers. It is sorted in order of + increasing timers. */ static struct { - /* Pointer to first in timer list. */ + /* Pointer to first in timer list. */ struct gdb_timer *first_timer; - /* Id of the last timer created. */ + /* 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. */ + this list. */ static struct { - /* Pointer to first in handler list. */ + /* Pointer to first in handler list. */ async_signal_handler *first_handler; - /* Pointer to last in handler list. */ + /* 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. */ + this list. */ static struct { - /* Pointer to first in handler list. */ + /* Pointer to first in handler list. */ async_event_handler *first_handler; - /* Pointer to last in handler list. */ + /* Pointer to last in handler list. */ async_event_handler *last_handler; } async_event_handler_list; @@ -260,192 +258,86 @@ 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 void check_async_signal_handlers (void); +static int check_async_event_handlers (void); static int gdb_wait_for_event (int); -static void poll_timers (void); +static int update_wait_timeout (void); +static int 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. */ +/* 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; - 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. */ +/* Callback registered with ASYNC_SIGNAL_HANDLERS_SERIAL_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) +static void +async_signals_handler (int error, gdb_client_data client_data) { - event_data data; - - data.integer = fd; - return create_event (handle_file_event, data); + /* Do nothing. Handlers are run by invoke_async_signal_handlers + from instead. */ } -/* 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) +void +initialize_async_signal_handlers (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; + async_signal_handlers_serial_event = make_serial_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; + 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). If an error - occurs catch_errors() which calls this function returns zero. */ + can happen if there are no event sources to wait for). */ int -gdb_do_one_event (void *data) +gdb_do_one_event (void) { 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 ()) + /* 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? If so, put an event on the - queue. */ - poll_timers (); + /* 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? */ - gdb_wait_for_event (0); + res = gdb_wait_for_event (0); break; case 2: /* Are there any asynchronous event handlers ready? */ - check_async_event_handlers (); + 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; - } - /* Handle any new events collected. */ - if (process_event ()) - return 1; + 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 @@ -455,49 +347,42 @@ gdb_do_one_event (void *data) 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. */ +/* 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. */ + /* 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 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. */ + int result = 0; - if (gdb_result == 0) + TRY { + result = gdb_do_one_event (); + } + CATCH (ex, RETURN_MASK_ALL) + { + 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 (); - /* 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); + /* 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; + observer_notify_command_error (); /* 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 @@ -507,19 +392,23 @@ start_event_loop (void) 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. */ + whether display the prompt or not. */ } + END_CATCH + + if (result < 0) + break; } - /* We are done with the event loop. There are no more event sources - to listen to. So we exit GDB. */ + /* 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. */ + vs. select. */ void add_file_handler (int fd, handler_func * proc, gdb_client_data client_data) { @@ -530,11 +419,11 @@ add_file_handler (int fd, handler_func * proc, gdb_client_data client_data) 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 + /* 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. */ + `poll'able. */ fds.fd = fd; fds.events = POLLIN; if (poll (&fds, 1, 0) == 1 && (fds.revents & POLLNVAL)) @@ -554,26 +443,32 @@ add_file_handler (int fd, handler_func * proc, gdb_client_data client_data) #endif } else - create_file_handler (fd, GDB_READABLE | GDB_EXCEPTION, proc, client_data); + 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. */ + 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) +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). */ + /* 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) { @@ -581,11 +476,11 @@ create_file_handler (int fd, int mask, handler_func * proc, gdb_client_data clie break; } - /* It is a new file descriptor. Add it to the list. Otherwise, just - change the data associated with it. */ + /* 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 = XNEW (file_handler); file_ptr->fd = fd; file_ptr->ready_mask = 0; file_ptr->next_file = gdb_notifier.first_file_handler; @@ -602,7 +497,7 @@ create_file_handler (int fd, int mask, handler_func * proc, gdb_client_data clie * sizeof (struct pollfd))); else gdb_notifier.poll_fds = - (struct pollfd *) xmalloc (sizeof (struct pollfd)); + 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; @@ -638,8 +533,33 @@ create_file_handler (int fd, int mask, handler_func * proc, gdb_client_data clie 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. */ + i.e. we don't care anymore about events on the FD. */ void delete_file_handler (int fd) { @@ -650,7 +570,7 @@ delete_file_handler (int fd) struct pollfd *new_poll_fds; #endif - /* Find the entry for the given file. */ + /* Find the entry for the given file. */ for (file_ptr = gdb_notifier.first_file_handler; file_ptr != NULL; file_ptr = file_ptr->next_file) @@ -665,11 +585,11 @@ delete_file_handler (int fd) 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. */ + /* 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)); + 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++) { @@ -677,7 +597,8 @@ delete_file_handler (int 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; + (new_poll_fds + j)->revents + = (gdb_notifier.poll_fds + i)->revents; j++; } } @@ -698,7 +619,7 @@ delete_file_handler (int fd) if (file_ptr->mask & GDB_EXCEPTION) FD_CLR (fd, &gdb_notifier.check_masks[2]); - /* Find current max fd. */ + /* Find current max fd. */ if ((fd + 1) == gdb_notifier.num_fds) { @@ -715,11 +636,22 @@ delete_file_handler (int fd) } /* Deactivate the file descriptor, by clearing its mask, - so that it will not fire again. */ + so that it will not fire again. */ file_ptr->mask = 0; - /* Get rid of the file handler in the file handler list. */ + /* 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 @@ -734,55 +666,46 @@ delete_file_handler (int fd) } /* 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. */ + corresponding file handler. */ + static void -handle_file_event (event_data data) +handle_file_event (file_handler *file_ptr, int ready_mask) { - 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. */ + 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). */ + 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 = (file_ptr->ready_mask & file_ptr->mask) | - (file_ptr->ready_mask & error_mask); - error_mask_returned = mask & error_mask; + mask = ready_mask & (file_ptr->mask | error_mask); - if (error_mask_returned != 0) + if ((mask & (POLLERR | POLLNVAL)) != 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); + /* 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 @@ -794,47 +717,47 @@ handle_file_event (event_data data) } else { - if (file_ptr->ready_mask & GDB_EXCEPTION) + if (ready_mask & GDB_EXCEPTION) { - printf_unfiltered (_("Exception condition detected on fd %d\n"), file_ptr->fd); + 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; + mask = 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 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. */ +/* 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; - gdb_event *file_event_ptr; int num_found = 0; - int i; - /* Make sure all output is done before getting another event. */ + /* 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 @@ -860,8 +783,8 @@ gdb_wait_for_event (int block) else { struct timeval select_timeout; - struct timeval *timeout_p; + if (block) timeout_p = gdb_notifier.timeout_valid ? &gdb_notifier.select_timeout : NULL; @@ -880,7 +803,7 @@ gdb_wait_for_event (int block) &gdb_notifier.ready_masks[2], timeout_p); - /* Clear the masks after an error from select. */ + /* Clear the masks after an error from select. */ if (num_found == -1) { FD_ZERO (&gdb_notifier.ready_masks[0]); @@ -894,38 +817,47 @@ gdb_wait_for_event (int block) } } - /* Enqueue all detected file events. */ + /* 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 - for (i = 0; (i < gdb_notifier.num_fds) && (num_found > 0); i++) + int i; + int mask; + + while (1) { - if ((gdb_notifier.poll_fds + i)->revents) - num_found--; - else - continue; + 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++; - 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 (i < gdb_notifier.num_fds); + if ((gdb_notifier.poll_fds + i)->revents) + 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; - } + 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")); @@ -933,11 +865,12 @@ gdb_wait_for_event (int block) } else { - for (file_ptr = gdb_notifier.first_file_handler; - (file_ptr != NULL) && (num_found > 0); - file_ptr = file_ptr->next_file) + /* See comment about even source fairness above. */ + int mask = 0; + + do { - int mask = 0; + file_ptr = get_next_file_handler_to_handle_and_advance (); if (FD_ISSET (file_ptr->fd, &gdb_notifier.ready_masks[0])) mask |= GDB_READABLE; @@ -945,40 +878,29 @@ gdb_wait_for_event (int block) 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; } + while (mask == 0); + + handle_file_event (file_ptr, mask); + return 1; } return 0; } -/* Create an asynchronous handler, allocating memory for it. +/* 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. */ + whenever the handler is invoked. */ async_signal_handler * -create_async_signal_handler (sig_handler_func * proc, gdb_client_data client_data) +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 = XNEW (async_signal_handler); async_handler_ptr->ready = 0; async_handler_ptr->next_handler = NULL; async_handler_ptr->proc = proc; @@ -991,34 +913,48 @@ create_async_signal_handler (sig_handler_func * proc, gdb_client_data client_dat 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. */ +/* 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 -call_async_signal_handler (struct async_signal_handler *handler) +mark_async_signal_handler (async_signal_handler * async_handler_ptr) { - (*handler->proc) (handler->client_data); + async_handler_ptr->ready = 1; + serial_event_set (async_signal_handlers_serial_event); } -/* 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. */ +/* See event-loop.h. */ + void -mark_async_signal_handler (async_signal_handler * async_handler_ptr) +clear_async_signal_handler (async_signal_handler *async_handler_ptr) { - async_handler_ptr->ready = 1; + 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; - /* Invoke ready handlers. */ + /* 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) { @@ -1033,13 +969,16 @@ invoke_async_signal_handlers (void) 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). +/* Delete an asynchronous handler (ASYNC_HANDLER_PTR). Free the space allocated for it. */ void delete_async_signal_handler (async_signal_handler ** async_handler_ptr) @@ -1057,6 +996,7 @@ delete_async_signal_handler (async_signal_handler ** async_handler_ptr) 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; @@ -1075,7 +1015,7 @@ create_async_event_handler (async_event_handler_func *proc, { async_event_handler *h; - h = xmalloc (sizeof (*h)); + h = XNEW (struct async_event_handler); h->ready = 0; h->next_handler = NULL; h->proc = proc; @@ -1098,32 +1038,21 @@ 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; -}; +/* See event-loop.h. */ -static void -invoke_async_event_handler (event_data data) +void +clear_async_event_handler (async_event_handler *async_handler_ptr) { - 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); + async_handler_ptr->ready = 0; } -/* Check if any asynchronous event handlers are ready, and queue - events in the ready queue for any that are. */ -static void +/* 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; - 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; @@ -1132,18 +1061,12 @@ check_async_event_handlers (void) 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); + (*async_handler_ptr->proc) (async_handler_ptr->client_data); + return 1; } } + + return 0; } /* Delete an asynchronous handler (ASYNC_HANDLER_PTR). @@ -1155,7 +1078,8 @@ delete_async_event_handler (async_event_handler **async_handler_ptr) if (async_event_handler_list.first_handler == *async_handler_ptr) { - async_event_handler_list.first_handler = (*async_handler_ptr)->next_handler; + 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; } @@ -1164,6 +1088,7 @@ delete_async_event_handler (async_event_handler **async_handler_ptr) 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; @@ -1172,49 +1097,35 @@ delete_async_event_handler (async_event_handler **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. */ +/* 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 milliseconds, timer_handler_func * proc, gdb_client_data client_data) +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; - struct timeval time_now, delta; - - /* compute seconds */ - delta.tv_sec = milliseconds / 1000; - /* compute microseconds */ - delta.tv_usec = (milliseconds % 1000) * 1000; - gettimeofday (&time_now, NULL); + steady_clock::time_point time_now = steady_clock::now (); - 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 = 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. */ + 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))) + if (timer_index->when > timer_ptr->when) break; } @@ -1240,13 +1151,13 @@ create_timer (int milliseconds, timer_handler_func * proc, gdb_client_data clien } /* There is a chance that the creator of the timer wants to get rid of - it before it expires. */ + it before it expires. */ void delete_timer (int id) { struct gdb_timer *timer_ptr, *prev_timer = NULL; - /* Find the entry for the given timer. */ + /* Find the entry for the given timer. */ for (timer_ptr = timer_list.first_timer; timer_ptr != NULL; timer_ptr = timer_ptr->next) @@ -1257,7 +1168,7 @@ delete_timer (int id) if (timer_ptr == NULL) return; - /* Get rid of the timer in the timer list. */ + /* Get rid of the timer in the timer list. */ if (timer_ptr == timer_list.first_timer) timer_list.first_timer = timer_ptr->next; else @@ -1268,92 +1179,56 @@ delete_timer (int id) ; prev_timer->next = timer_ptr->next; } - xfree (timer_ptr); + delete 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; +/* Convert a std::chrono duration to a struct timeval. */ - 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; +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; } -/* 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; +/* 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) { - 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; - } + using namespace std::chrono; + steady_clock::time_point time_now = steady_clock::now (); + struct timeval timeout; - /* 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)) + if (timer_list.first_timer->when < time_now) { - delta.tv_sec = 0; - delta.tv_usec = 0; + /* It expired already. */ + timeout.tv_sec = 0; + timeout.tv_usec = 0; } - - if (delta.tv_sec == 0 && delta.tv_usec == 0) + else { - 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); + steady_clock::duration d = timer_list.first_timer->when - time_now; + timeout = duration_cast_timeval (d); } - /* Now we need to update the timeout for select/ poll, because we - don't want to sit there while this timer is expiring. */ + /* Update the timeout for select/ poll. */ if (use_poll) { #ifdef HAVE_POLL - gdb_notifier.poll_timeout = delta.tv_sec * 1000; + gdb_notifier.poll_timeout = timeout.tv_sec * 1000; #else internal_error (__FILE__, __LINE__, _("use_poll without HAVE_POLL")); @@ -1361,11 +1236,47 @@ poll_timers (void) } else { - gdb_notifier.select_timeout.tv_sec = delta.tv_sec; - gdb_notifier.select_timeout.tv_usec = delta.tv_usec; + 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; }