binutils-gdb/gdb/gdbserver/event-loop.c
Pedro Alves bd99dc8583 Non-stop mode support.
* server.h (non_stop): Declare.
	(gdb_client_data, handler_func): Declare.
	(delete_file_handler, add_file_handler, start_event_loop):
	Declare.
	(handle_serial_event, handle_target_event, push_event)
	(putpkt_notif): Declare.
	* target.h (enum resume_kind): New.
	(struct thread_resume): Replace `step' field by `kind' field.
	(TARGET_WNOHANG): Define.
	(struct target_ops) <wait>: Add `options' argument.
	<supports_non_stop, async, start_non_stop>: New fields.
	(target_supports_non_stop, target_async): New.
	(start_non_stop): Declare.
	(mywait): Add `options' argument.
	* target.c (mywait): Add `options' argument.  Print child exit
	notifications here.
	(start_non_stop): New.
	* server.c (non_stop, own_buf, mem_buf): New globals.
	(struct vstop_notif): New.
	(notif_queue): New global.
	(queue_stop_reply, push_event, discard_queued_stop_replies)
	(send_next_stop_reply): New.
	(start_inferior): Adjust to use resume_kind.  Adjust to mywait
	interface changes.
	(attach_inferior): In non-stop mode, don't wait for the target
	here.
	(handle_general_set): Handle QNonStop.
	(handle_query): When handling qC, return the current general
	thread, instead of the first thread of the list.
	(handle_query): If the backend supports non-stop mode, include
	QNonStop+ in the qSupported query response.
	(handle_v_cont): Adjust to use resume_kind.  Handle resume_stop
	and non-stop mode.
	(handle_v_attach, handle_v_run): Handle non-stop mode.
	(handle_v_stopped): New.
	(handle_v_requests): Report support for vCont;t.  Handle vStopped.
	(myresume): Adjust to use resume_kind.  Handle non-stop.
	(queue_stop_reply_callback): New.
	(handle_status): Handle non-stop mode.
	(main): Clear non_stop flag on reconnection.  Use the event-loop.
	Refactor serial protocol handling from here ...
	(process_serial_event): ... to this new function.  When GDB
	selects any thread, select one here.  In non-stop mode, wait until
	GDB acks all pending events before exiting.
	(handle_serial_event, handle_target_event): New.
	* remote-utils.c (remote_open): Install remote_desc in the event
	loop.
	(remote_close): Remove remote_desc from the event loop.
	(putpkt_binary): Rename to...
	(putpkt_binary_1): ... this.  Add `is_notic' argument.  Handle it.
	(putpkt_binary): New as wrapper around putpkt_binary_1.
	(putpkt_notif): New.
	(prepare_resume_reply): In non-stop mode, don't change the
	general_thread.
	* event-loop.c: New.
	* Makefile.in (OBJ): Add event-loop.o.
	(event-loop.o): New rule.

	* linux-low.h (pid_of): Moved here.
	(lwpid_of): New.
	(get_lwp_thread): Use lwpid_of.
	(struct lwp_info): Delete `lwpid' field.  Add `suspended' field.
	* linux-low.c (pid_of): Delete.
	(inferior_pid): Use lwpid_of.
	(linux_event_pipe): New.
	(target_is_async_p): New.
	(delete_lwp): New.
	(handle_extended_wait): Use lwpid_of.
	(add_lwp): Don't set lwpid field.
	(linux_attach_lwp): Adjust debug output.  Use lwpid_of.
	(linux_kill_one_lwp): If killing a running lwp, stop it first.
	Use lwpid_of.  Adjust to linux_wait_for_event interface changes.
	(linux_detach_one_lwp): If detaching from a running lwp, stop it
	first.  Adjust to linux_wait_for_event interface changes.  Use
	lwpid_of.
	(linux_detach): Don't delete the main lwp here.
	(linux_join): Use my_waitpid.  Avoid signal_pid.  Use lwpid_of.
	(status_pending_p): Don't consider explicitly suspended lwps.
	(linux_wait_for_lwp): Take an integer pid instead of a lwp_info
	pointer.  Add OPTIONS argument.  Change return type to int.  Use
	my_waitpid instead of sleeping.  Handle WNOHANG.  Use lwpid_of.
	(linux_wait_for_event): Take an integer pid instead of a lwp_info
	pointer.  Add status pointer argument.  Return a pid instead of a
	status.  Use lwpid_of.  Adjust to linux_wait_for_lwp interface
	changes.  In non-stop mode, don't switch to a random thread.
	(linux_wait): Rename to...
	(linux_wait_1): ... this.  Add target_options argument, and handle
	it.  Adjust to use resume_kind.  Use lwpid_of.  In non-stop mode,
	don't handle the continue thread.  Handle TARGET_WNOHANG.  Merge
	clean exit and signal exit code.  Don't stop all threads in
	non-stop mode.  In all-stop mode, only stop all threads when
	reporting a stop to GDB.  Handle explicit thread stop requests.
	(async_file_flush, async_file_mark): New.
	(linux_wait): New.
	(send_sigstop): Use lwpid_of.
	(wait_for_sigstop): Use lwpid_of.  Adjust to linux_wait_for_event
	interface changes.  In non-stop mode, don't switch to a random
	thread.
	(linux_resume_one_lwp): Use lwpid_of.
	(linux_continue_one_thread, linux_queue_one_thread): Merge into ...
	(linux_resume_one_thread): ... this.  Handle resume_stop.  In
	non-stop mode, don't look for pending flag in all threads.
	(resume_status_pending_p): Don't consider explicitly suspended
	threads.
	(my_waitpid): Reimplement.  Emulate __WALL.
	(linux_request_interrupt, linux_read_offsets, linux_xfer_siginfo):
	Use lwpid_of.
	(sigchld_handler, linux_supports_non_stop, linux_async)
	(linux_start_non_stop): New.
	(linux_target_ops): Register linux_supports_non_stop, linux_async
	and linux_start_non_stop.
	(initialize_low): Install SIGCHLD handler.
	* thread-db.c (thread_db_create_event, find_one_thread)
	(thread_db_get_tls_address): Use lwpid_of.
	* win32-low.c (win32_detach): Adjust to use resume_kind.
	(win32_wait): Add `options' argument.
	* spu-low.c (spu_resume): Adjust to use resume_kind.
	(spu_wait): Add `options' argument.
2009-04-01 22:48:05 +00:00

505 lines
14 KiB
C

/* Event loop machinery for the remote server for GDB.
Copyright (C) 1999, 2000, 2001, 2002, 2005, 2006, 2007, 2008
Free Software Foundation, Inc.
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/>. */
/* Based on src/gdb/event-loop.c. */
#include "server.h"
#include <sys/types.h>
#include <string.h>
#include <sys/time.h>
#ifdef USE_WIN32API
#include <windows.h>
#include <io.h>
#endif
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
typedef struct gdb_event gdb_event;
typedef void (event_handler_func) (int);
/* Tell create_file_handler what events we are interested in. */
#define GDB_READABLE (1<<1)
#define GDB_WRITABLE (1<<2)
#define GDB_EXCEPTION (1<<3)
/* Events are queued by calling async_queue_event and serviced later
on by 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
{
/* Procedure to call to service this event. */
event_handler_func *proc;
/* File descriptor that is ready. */
int fd;
/* 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
{
/* File descriptor. */
int fd;
/* Events we want to monitor. */
int mask;
/* Events that have been seen since the last time. */
int ready_mask;
/* Procedure to call when fd is ready. */
handler_func *proc;
/* Argument to pass to proc. */
gdb_client_data client_data;
/* Was an error detected on this fd? */
int error;
/* Next registered file descriptor. */
struct file_handler *next_file;
}
file_handler;
/* Event 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
{
/* The first pending event. */
gdb_event *first_event;
/* The last pending event. */
gdb_event *last_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. 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. */
static struct
{
/* Ptr to head of file handler list. */
file_handler *first_file_handler;
/* 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 valid bits (highest fd value + 1). (for select) */
int num_fds;
}
gdb_notifier;
/* Insert an event object into the gdb event queue.
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 will be processed first in first
out. */
static void
async_queue_event (gdb_event *event_ptr)
{
/* 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;
}
/* Process one event. If an event was processed, 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;
/* 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, since the
proc function could end up jumping out to the caller of this
function. In that case, we would have on the event queue an
event which 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;
}
free (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;
}
/* 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. 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 = xmalloc (sizeof (*file_ptr));
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 (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;
}
/* Wrapper function for create_file_handler. */
void
add_file_handler (int fd, handler_func *proc, gdb_client_data client_data)
{
create_file_handler (fd, GDB_READABLE | GDB_EXCEPTION, proc, client_data);
}
/* 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;
/* 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 (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;
}
free (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;
/* 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)
{
/* See if the desired events (mask) match the received
events (ready_mask). */
if (file_ptr->ready_mask & GDB_EXCEPTION)
{
fprintf (stderr, "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;
}
}
}
/* 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 = xmalloc (sizeof (gdb_event));
file_event_ptr->proc = handle_file_event;
file_event_ptr->fd = fd;
return file_event_ptr;
}
/* Called by 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
select. Return -1 if there are no files descriptors to monitor,
otherwise return 0. */
static int
wait_for_event (void)
{
file_handler *file_ptr;
gdb_event *file_event_ptr;
int num_found = 0;
/* Make sure all output is done before getting another event. */
fflush (stdout);
fflush (stderr);
if (gdb_notifier.num_fds == 0)
return -1;
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],
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]);
#ifdef EINTR
/* Dont print anything if we got a signal, let gdb handle
it. */
if (errno != EINTR)
perror_with_name ("select");
#endif
}
/* Enqueue all detected file events. */
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);
}
file_ptr->ready_mask = mask;
}
return 0;
}
/* Start up the event loop. This is the entry point to the event
loop. */
void
start_event_loop (void)
{
/* Loop until there is nothing to do. This is the entry point to
the event loop engine. If nothing is ready at this time, wait
for something to happen (via wait_for_event), then process it.
Return when there are no longer event sources to wait for. */
while (1)
{
/* Any events already waiting in the queue? */
if (process_event ())
continue;
/* Wait for a new event. If 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 (wait_for_event () < 0)
return;
}
/* We are done with the event loop. There are no more event sources
to listen to. So we exit gdbserver. */
}