913 lines
25 KiB
C++
913 lines
25 KiB
C++
/* Event loop machinery for GDB, the GNU debugger.
|
||
Copyright (C) 1999-2022 Free Software Foundation, Inc.
|
||
Written by Elena Zannoni <ezannoni@cygnus.com> of Cygnus Solutions.
|
||
|
||
This file is part of GDB.
|
||
|
||
This program is free software; you can redistribute it and/or modify
|
||
it under the terms of the GNU General Public License as published by
|
||
the Free Software Foundation; either version 3 of the License, or
|
||
(at your option) any later version.
|
||
|
||
This program is distributed in the hope that it will be useful,
|
||
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||
GNU General Public License for more details.
|
||
|
||
You should have received a copy of the GNU General Public License
|
||
along with this program. If not, see <http://www.gnu.org/licenses/>. */
|
||
|
||
#include "gdbsupport/common-defs.h"
|
||
#include "gdbsupport/event-loop.h"
|
||
|
||
#include <chrono>
|
||
|
||
#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 "gdbsupport/gdb_sys_time.h"
|
||
#include "gdbsupport/gdb_select.h"
|
||
|
||
/* See event-loop.h. */
|
||
|
||
debug_event_loop_kind debug_event_loop;
|
||
|
||
/* 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)
|
||
|
||
/* Information about each file descriptor we register with the event
|
||
loop. */
|
||
|
||
struct file_handler
|
||
{
|
||
/* File descriptor. */
|
||
int fd;
|
||
|
||
/* Events we want to monitor: POLLIN, etc. */
|
||
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;
|
||
|
||
/* User-friendly name of this handler. */
|
||
std::string name;
|
||
|
||
/* If set, this file descriptor is used for a user interface. */
|
||
bool is_ui;
|
||
|
||
/* Was an error detected on this fd? */
|
||
int error;
|
||
|
||
/* Next registered file descriptor. */
|
||
struct file_handler *next_file;
|
||
};
|
||
|
||
/* Do we use poll or select ? */
|
||
#ifdef HAVE_POLL
|
||
#define USE_POLL 1
|
||
#else
|
||
#define USE_POLL 0
|
||
#endif /* HAVE_POLL */
|
||
|
||
static unsigned char use_poll = USE_POLL;
|
||
|
||
#ifdef USE_WIN32API
|
||
#include <windows.h>
|
||
#include <io.h>
|
||
#endif
|
||
|
||
/* 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. */
|
||
|
||
static struct
|
||
{
|
||
/* Ptr to head of file handler list. */
|
||
file_handler *first_file_handler;
|
||
|
||
/* Next file handler to handle, for the select variant. To level
|
||
the fairness across event sources, we serve file handlers in a
|
||
round-robin-like fashion. The number and order of the polled
|
||
file handlers may change between invocations, but this is good
|
||
enough. */
|
||
file_handler *next_file_handler;
|
||
|
||
#ifdef HAVE_POLL
|
||
/* Ptr to array of pollfd structures. */
|
||
struct pollfd *poll_fds;
|
||
|
||
/* Next file descriptor to handle, for the poll variant. To level
|
||
the fairness across event sources, we poll the file descriptors
|
||
in a round-robin-like fashion. The number and order of the
|
||
polled file descriptors may change between invocations, but
|
||
this is good enough. */
|
||
int next_poll_fds_index;
|
||
|
||
/* Timeout in milliseconds for calls to poll(). */
|
||
int poll_timeout;
|
||
#endif
|
||
|
||
/* Masks to be used in the next call to select.
|
||
Bits are set in response to calls to create_file_handler. */
|
||
fd_set check_masks[3];
|
||
|
||
/* What file descriptors were found ready by select. */
|
||
fd_set ready_masks[3];
|
||
|
||
/* Number of file descriptors to monitor (for poll). */
|
||
/* Number of valid bits (highest fd value + 1) (for select). */
|
||
int num_fds;
|
||
|
||
/* Time structure for calls to select(). */
|
||
struct timeval select_timeout;
|
||
|
||
/* Flag to tell whether the timeout should be used. */
|
||
int timeout_valid;
|
||
}
|
||
gdb_notifier;
|
||
|
||
/* Structure associated with a timer. PROC will be executed at the
|
||
first occasion after WHEN. */
|
||
struct gdb_timer
|
||
{
|
||
std::chrono::steady_clock::time_point when;
|
||
int timer_id;
|
||
struct gdb_timer *next;
|
||
timer_handler_func *proc; /* Function to call to do the work. */
|
||
gdb_client_data client_data; /* Argument to async_handler_func. */
|
||
};
|
||
|
||
/* List of currently active timers. It is sorted in order of
|
||
increasing timers. */
|
||
static struct
|
||
{
|
||
/* Pointer to first in timer list. */
|
||
struct gdb_timer *first_timer;
|
||
|
||
/* Id of the last timer created. */
|
||
int num_timers;
|
||
}
|
||
timer_list;
|
||
|
||
static void create_file_handler (int fd, int mask, handler_func *proc,
|
||
gdb_client_data client_data,
|
||
std::string &&name, bool is_ui);
|
||
static int gdb_wait_for_event (int);
|
||
static int update_wait_timeout (void);
|
||
static int poll_timers (void);
|
||
|
||
/* Process one high level event. If nothing is ready at this time,
|
||
wait for something to happen (via gdb_wait_for_event), then process
|
||
it. Returns >0 if something was done otherwise returns <0 (this
|
||
can happen if there are no event sources to wait for). */
|
||
|
||
int
|
||
gdb_do_one_event (void)
|
||
{
|
||
static int event_source_head = 0;
|
||
const int number_of_sources = 3;
|
||
int current = 0;
|
||
|
||
/* First let's see if there are any asynchronous signal handlers
|
||
that are ready. These would be the result of invoking any of the
|
||
signal handlers. */
|
||
if (invoke_async_signal_handlers ())
|
||
return 1;
|
||
|
||
/* To level the fairness across event sources, we poll them in a
|
||
round-robin fashion. */
|
||
for (current = 0; current < number_of_sources; current++)
|
||
{
|
||
int res;
|
||
|
||
switch (event_source_head)
|
||
{
|
||
case 0:
|
||
/* Are any timers that are ready? */
|
||
res = poll_timers ();
|
||
break;
|
||
case 1:
|
||
/* Are there events already waiting to be collected on the
|
||
monitored file descriptors? */
|
||
res = gdb_wait_for_event (0);
|
||
break;
|
||
case 2:
|
||
/* Are there any asynchronous event handlers ready? */
|
||
res = check_async_event_handlers ();
|
||
break;
|
||
default:
|
||
internal_error (__FILE__, __LINE__,
|
||
"unexpected event_source_head %d",
|
||
event_source_head);
|
||
}
|
||
|
||
event_source_head++;
|
||
if (event_source_head == number_of_sources)
|
||
event_source_head = 0;
|
||
|
||
if (res > 0)
|
||
return 1;
|
||
}
|
||
|
||
/* Block waiting for a new event. If gdb_wait_for_event returns -1,
|
||
we should get out because this means that there are no event
|
||
sources left. This will make the event loop stop, and the
|
||
application exit. */
|
||
|
||
if (gdb_wait_for_event (1) < 0)
|
||
return -1;
|
||
|
||
/* If gdb_wait_for_event has returned 1, it means that one event has
|
||
been handled. We break out of the loop. */
|
||
return 1;
|
||
}
|
||
|
||
/* See event-loop.h */
|
||
|
||
void
|
||
add_file_handler (int fd, handler_func *proc, gdb_client_data client_data,
|
||
std::string &&name, bool is_ui)
|
||
{
|
||
#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, std::move (name),
|
||
is_ui);
|
||
#else
|
||
internal_error (__FILE__, __LINE__,
|
||
_("use_poll without HAVE_POLL"));
|
||
#endif
|
||
}
|
||
else
|
||
create_file_handler (fd, GDB_READABLE | GDB_EXCEPTION,
|
||
proc, client_data, std::move (name), is_ui);
|
||
}
|
||
|
||
/* Helper for add_file_handler.
|
||
|
||
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, std::string &&name,
|
||
bool is_ui)
|
||
{
|
||
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 = new file_handler;
|
||
file_ptr->fd = fd;
|
||
file_ptr->ready_mask = 0;
|
||
file_ptr->next_file = gdb_notifier.first_file_handler;
|
||
gdb_notifier.first_file_handler = file_ptr;
|
||
|
||
if (use_poll)
|
||
{
|
||
#ifdef HAVE_POLL
|
||
gdb_notifier.num_fds++;
|
||
if (gdb_notifier.poll_fds)
|
||
gdb_notifier.poll_fds =
|
||
(struct pollfd *) xrealloc (gdb_notifier.poll_fds,
|
||
(gdb_notifier.num_fds
|
||
* sizeof (struct pollfd)));
|
||
else
|
||
gdb_notifier.poll_fds =
|
||
XNEW (struct pollfd);
|
||
(gdb_notifier.poll_fds + gdb_notifier.num_fds - 1)->fd = fd;
|
||
(gdb_notifier.poll_fds + gdb_notifier.num_fds - 1)->events = mask;
|
||
(gdb_notifier.poll_fds + gdb_notifier.num_fds - 1)->revents = 0;
|
||
#else
|
||
internal_error (__FILE__, __LINE__,
|
||
_("use_poll without HAVE_POLL"));
|
||
#endif /* HAVE_POLL */
|
||
}
|
||
else
|
||
{
|
||
if (mask & GDB_READABLE)
|
||
FD_SET (fd, &gdb_notifier.check_masks[0]);
|
||
else
|
||
FD_CLR (fd, &gdb_notifier.check_masks[0]);
|
||
|
||
if (mask & GDB_WRITABLE)
|
||
FD_SET (fd, &gdb_notifier.check_masks[1]);
|
||
else
|
||
FD_CLR (fd, &gdb_notifier.check_masks[1]);
|
||
|
||
if (mask & GDB_EXCEPTION)
|
||
FD_SET (fd, &gdb_notifier.check_masks[2]);
|
||
else
|
||
FD_CLR (fd, &gdb_notifier.check_masks[2]);
|
||
|
||
if (gdb_notifier.num_fds <= fd)
|
||
gdb_notifier.num_fds = fd + 1;
|
||
}
|
||
}
|
||
|
||
file_ptr->proc = proc;
|
||
file_ptr->client_data = client_data;
|
||
file_ptr->mask = mask;
|
||
file_ptr->name = std::move (name);
|
||
file_ptr->is_ui = is_ui;
|
||
}
|
||
|
||
/* Return the next file handler to handle, and advance to the next
|
||
file handler, wrapping around if the end of the list is
|
||
reached. */
|
||
|
||
static file_handler *
|
||
get_next_file_handler_to_handle_and_advance (void)
|
||
{
|
||
file_handler *curr_next;
|
||
|
||
/* The first time around, this is still NULL. */
|
||
if (gdb_notifier.next_file_handler == NULL)
|
||
gdb_notifier.next_file_handler = gdb_notifier.first_file_handler;
|
||
|
||
curr_next = gdb_notifier.next_file_handler;
|
||
gdb_assert (curr_next != NULL);
|
||
|
||
/* Advance. */
|
||
gdb_notifier.next_file_handler = curr_next->next_file;
|
||
/* Wrap around, if necessary. */
|
||
if (gdb_notifier.next_file_handler == NULL)
|
||
gdb_notifier.next_file_handler = gdb_notifier.first_file_handler;
|
||
|
||
return curr_next;
|
||
}
|
||
|
||
/* Remove the file descriptor FD from the list of monitored fd's:
|
||
i.e. we don't care anymore about events on the FD. */
|
||
void
|
||
delete_file_handler (int fd)
|
||
{
|
||
file_handler *file_ptr, *prev_ptr = NULL;
|
||
int i;
|
||
#ifdef HAVE_POLL
|
||
int j;
|
||
struct pollfd *new_poll_fds;
|
||
#endif
|
||
|
||
/* Find the entry for the given file. */
|
||
|
||
for (file_ptr = gdb_notifier.first_file_handler; file_ptr != NULL;
|
||
file_ptr = file_ptr->next_file)
|
||
{
|
||
if (file_ptr->fd == fd)
|
||
break;
|
||
}
|
||
|
||
if (file_ptr == NULL)
|
||
return;
|
||
|
||
if (use_poll)
|
||
{
|
||
#ifdef HAVE_POLL
|
||
/* Create a new poll_fds array by copying every fd's information
|
||
but the one we want to get rid of. */
|
||
|
||
new_poll_fds = (struct pollfd *)
|
||
xmalloc ((gdb_notifier.num_fds - 1) * sizeof (struct pollfd));
|
||
|
||
for (i = 0, j = 0; i < gdb_notifier.num_fds; i++)
|
||
{
|
||
if ((gdb_notifier.poll_fds + i)->fd != fd)
|
||
{
|
||
(new_poll_fds + j)->fd = (gdb_notifier.poll_fds + i)->fd;
|
||
(new_poll_fds + j)->events = (gdb_notifier.poll_fds + i)->events;
|
||
(new_poll_fds + j)->revents
|
||
= (gdb_notifier.poll_fds + i)->revents;
|
||
j++;
|
||
}
|
||
}
|
||
xfree (gdb_notifier.poll_fds);
|
||
gdb_notifier.poll_fds = new_poll_fds;
|
||
gdb_notifier.num_fds--;
|
||
#else
|
||
internal_error (__FILE__, __LINE__,
|
||
_("use_poll without HAVE_POLL"));
|
||
#endif /* HAVE_POLL */
|
||
}
|
||
else
|
||
{
|
||
if (file_ptr->mask & GDB_READABLE)
|
||
FD_CLR (fd, &gdb_notifier.check_masks[0]);
|
||
if (file_ptr->mask & GDB_WRITABLE)
|
||
FD_CLR (fd, &gdb_notifier.check_masks[1]);
|
||
if (file_ptr->mask & GDB_EXCEPTION)
|
||
FD_CLR (fd, &gdb_notifier.check_masks[2]);
|
||
|
||
/* Find current max fd. */
|
||
|
||
if ((fd + 1) == gdb_notifier.num_fds)
|
||
{
|
||
gdb_notifier.num_fds--;
|
||
for (i = gdb_notifier.num_fds; i; i--)
|
||
{
|
||
if (FD_ISSET (i - 1, &gdb_notifier.check_masks[0])
|
||
|| FD_ISSET (i - 1, &gdb_notifier.check_masks[1])
|
||
|| FD_ISSET (i - 1, &gdb_notifier.check_masks[2]))
|
||
break;
|
||
}
|
||
gdb_notifier.num_fds = i;
|
||
}
|
||
}
|
||
|
||
/* Deactivate the file descriptor, by clearing its mask,
|
||
so that it will not fire again. */
|
||
|
||
file_ptr->mask = 0;
|
||
|
||
/* If this file handler was going to be the next one to be handled,
|
||
advance to the next's next, if any. */
|
||
if (gdb_notifier.next_file_handler == file_ptr)
|
||
{
|
||
if (file_ptr->next_file == NULL
|
||
&& file_ptr == gdb_notifier.first_file_handler)
|
||
gdb_notifier.next_file_handler = NULL;
|
||
else
|
||
get_next_file_handler_to_handle_and_advance ();
|
||
}
|
||
|
||
/* Get rid of the file handler in the file handler list. */
|
||
if (file_ptr == gdb_notifier.first_file_handler)
|
||
gdb_notifier.first_file_handler = file_ptr->next_file;
|
||
else
|
||
{
|
||
for (prev_ptr = gdb_notifier.first_file_handler;
|
||
prev_ptr->next_file != file_ptr;
|
||
prev_ptr = prev_ptr->next_file)
|
||
;
|
||
prev_ptr->next_file = file_ptr->next_file;
|
||
}
|
||
|
||
delete file_ptr;
|
||
}
|
||
|
||
/* Handle the given event by calling the procedure associated to the
|
||
corresponding file handler. */
|
||
|
||
static void
|
||
handle_file_event (file_handler *file_ptr, int ready_mask)
|
||
{
|
||
int mask;
|
||
#ifdef HAVE_POLL
|
||
int error_mask;
|
||
#endif
|
||
|
||
{
|
||
{
|
||
/* With poll, the ready_mask could have any of three events
|
||
set to 1: POLLHUP, POLLERR, POLLNVAL. These events
|
||
cannot be used in the requested event mask (events), but
|
||
they can be returned in the return mask (revents). We
|
||
need to check for those event too, and add them to the
|
||
mask which will be passed to the handler. */
|
||
|
||
/* See if the desired events (mask) match the received
|
||
events (ready_mask). */
|
||
|
||
if (use_poll)
|
||
{
|
||
#ifdef HAVE_POLL
|
||
/* POLLHUP means EOF, but can be combined with POLLIN to
|
||
signal more data to read. */
|
||
error_mask = POLLHUP | POLLERR | POLLNVAL;
|
||
mask = ready_mask & (file_ptr->mask | error_mask);
|
||
|
||
if ((mask & (POLLERR | POLLNVAL)) != 0)
|
||
{
|
||
/* Work in progress. We may need to tell somebody
|
||
what kind of error we had. */
|
||
if (mask & POLLERR)
|
||
warning (_("Error detected on fd %d"), file_ptr->fd);
|
||
if (mask & POLLNVAL)
|
||
warning (_("Invalid or non-`poll'able fd %d"),
|
||
file_ptr->fd);
|
||
file_ptr->error = 1;
|
||
}
|
||
else
|
||
file_ptr->error = 0;
|
||
#else
|
||
internal_error (__FILE__, __LINE__,
|
||
_("use_poll without HAVE_POLL"));
|
||
#endif /* HAVE_POLL */
|
||
}
|
||
else
|
||
{
|
||
if (ready_mask & GDB_EXCEPTION)
|
||
{
|
||
warning (_("Exception condition detected on fd %d"),
|
||
file_ptr->fd);
|
||
file_ptr->error = 1;
|
||
}
|
||
else
|
||
file_ptr->error = 0;
|
||
mask = ready_mask & file_ptr->mask;
|
||
}
|
||
|
||
/* If there was a match, then call the handler. */
|
||
if (mask != 0)
|
||
{
|
||
event_loop_ui_debug_printf (file_ptr->is_ui,
|
||
"invoking fd file handler `%s`",
|
||
file_ptr->name.c_str ());
|
||
file_ptr->proc (file_ptr->error, file_ptr->client_data);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Wait for new events on the monitored file descriptors. Run the
|
||
event handler if the first descriptor that is detected by the poll.
|
||
If BLOCK and if there are no events, this function will block in
|
||
the call to poll. Return 1 if an event was handled. Return -1 if
|
||
there are no file descriptors to monitor. Return 1 if an event was
|
||
handled, otherwise returns 0. */
|
||
|
||
static int
|
||
gdb_wait_for_event (int block)
|
||
{
|
||
file_handler *file_ptr;
|
||
int num_found = 0;
|
||
|
||
/* Make sure all output is done before getting another event. */
|
||
flush_streams ();
|
||
|
||
if (gdb_notifier.num_fds == 0)
|
||
return -1;
|
||
|
||
if (block)
|
||
update_wait_timeout ();
|
||
|
||
if (use_poll)
|
||
{
|
||
#ifdef HAVE_POLL
|
||
int timeout;
|
||
|
||
if (block)
|
||
timeout = gdb_notifier.timeout_valid ? gdb_notifier.poll_timeout : -1;
|
||
else
|
||
timeout = 0;
|
||
|
||
num_found = poll (gdb_notifier.poll_fds,
|
||
(unsigned long) gdb_notifier.num_fds, timeout);
|
||
|
||
/* Don't print anything if we get out of poll because of a
|
||
signal. */
|
||
if (num_found == -1 && errno != EINTR)
|
||
perror_with_name (("poll"));
|
||
#else
|
||
internal_error (__FILE__, __LINE__,
|
||
_("use_poll without HAVE_POLL"));
|
||
#endif /* HAVE_POLL */
|
||
}
|
||
else
|
||
{
|
||
struct timeval select_timeout;
|
||
struct timeval *timeout_p;
|
||
|
||
if (block)
|
||
timeout_p = gdb_notifier.timeout_valid
|
||
? &gdb_notifier.select_timeout : NULL;
|
||
else
|
||
{
|
||
memset (&select_timeout, 0, sizeof (select_timeout));
|
||
timeout_p = &select_timeout;
|
||
}
|
||
|
||
gdb_notifier.ready_masks[0] = gdb_notifier.check_masks[0];
|
||
gdb_notifier.ready_masks[1] = gdb_notifier.check_masks[1];
|
||
gdb_notifier.ready_masks[2] = gdb_notifier.check_masks[2];
|
||
num_found = gdb_select (gdb_notifier.num_fds,
|
||
&gdb_notifier.ready_masks[0],
|
||
&gdb_notifier.ready_masks[1],
|
||
&gdb_notifier.ready_masks[2],
|
||
timeout_p);
|
||
|
||
/* Clear the masks after an error from select. */
|
||
if (num_found == -1)
|
||
{
|
||
FD_ZERO (&gdb_notifier.ready_masks[0]);
|
||
FD_ZERO (&gdb_notifier.ready_masks[1]);
|
||
FD_ZERO (&gdb_notifier.ready_masks[2]);
|
||
|
||
/* Dont print anything if we got a signal, let gdb handle
|
||
it. */
|
||
if (errno != EINTR)
|
||
perror_with_name (("select"));
|
||
}
|
||
}
|
||
|
||
/* Avoid looking at poll_fds[i]->revents if no event fired. */
|
||
if (num_found <= 0)
|
||
return 0;
|
||
|
||
/* Run event handlers. We always run just one handler and go back
|
||
to polling, in case a handler changes the notifier list. Since
|
||
events for sources we haven't consumed yet wake poll/select
|
||
immediately, no event is lost. */
|
||
|
||
/* To level the fairness across event descriptors, we handle them in
|
||
a round-robin-like fashion. The number and order of descriptors
|
||
may change between invocations, but this is good enough. */
|
||
if (use_poll)
|
||
{
|
||
#ifdef HAVE_POLL
|
||
int i;
|
||
int mask;
|
||
|
||
while (1)
|
||
{
|
||
if (gdb_notifier.next_poll_fds_index >= gdb_notifier.num_fds)
|
||
gdb_notifier.next_poll_fds_index = 0;
|
||
i = gdb_notifier.next_poll_fds_index++;
|
||
|
||
gdb_assert (i < gdb_notifier.num_fds);
|
||
if ((gdb_notifier.poll_fds + i)->revents)
|
||
break;
|
||
}
|
||
|
||
for (file_ptr = gdb_notifier.first_file_handler;
|
||
file_ptr != NULL;
|
||
file_ptr = file_ptr->next_file)
|
||
{
|
||
if (file_ptr->fd == (gdb_notifier.poll_fds + i)->fd)
|
||
break;
|
||
}
|
||
gdb_assert (file_ptr != NULL);
|
||
|
||
mask = (gdb_notifier.poll_fds + i)->revents;
|
||
handle_file_event (file_ptr, mask);
|
||
return 1;
|
||
#else
|
||
internal_error (__FILE__, __LINE__,
|
||
_("use_poll without HAVE_POLL"));
|
||
#endif /* HAVE_POLL */
|
||
}
|
||
else
|
||
{
|
||
/* See comment about even source fairness above. */
|
||
int mask = 0;
|
||
|
||
do
|
||
{
|
||
file_ptr = get_next_file_handler_to_handle_and_advance ();
|
||
|
||
if (FD_ISSET (file_ptr->fd, &gdb_notifier.ready_masks[0]))
|
||
mask |= GDB_READABLE;
|
||
if (FD_ISSET (file_ptr->fd, &gdb_notifier.ready_masks[1]))
|
||
mask |= GDB_WRITABLE;
|
||
if (FD_ISSET (file_ptr->fd, &gdb_notifier.ready_masks[2]))
|
||
mask |= GDB_EXCEPTION;
|
||
}
|
||
while (mask == 0);
|
||
|
||
handle_file_event (file_ptr, mask);
|
||
return 1;
|
||
}
|
||
return 0;
|
||
}
|
||
|
||
/* Create a timer that will expire in MS milliseconds from now. When
|
||
the timer is ready, PROC will be executed. At creation, the timer
|
||
is added to the timers queue. This queue is kept sorted in order
|
||
of increasing timers. Return a handle to the timer struct. */
|
||
|
||
int
|
||
create_timer (int ms, timer_handler_func *proc,
|
||
gdb_client_data client_data)
|
||
{
|
||
using namespace std::chrono;
|
||
struct gdb_timer *timer_ptr, *timer_index, *prev_timer;
|
||
|
||
steady_clock::time_point time_now = steady_clock::now ();
|
||
|
||
timer_ptr = new gdb_timer ();
|
||
timer_ptr->when = time_now + milliseconds (ms);
|
||
timer_ptr->proc = proc;
|
||
timer_ptr->client_data = client_data;
|
||
timer_list.num_timers++;
|
||
timer_ptr->timer_id = timer_list.num_timers;
|
||
|
||
/* Now add the timer to the timer queue, making sure it is sorted in
|
||
increasing order of expiration. */
|
||
|
||
for (timer_index = timer_list.first_timer;
|
||
timer_index != NULL;
|
||
timer_index = timer_index->next)
|
||
{
|
||
if (timer_index->when > timer_ptr->when)
|
||
break;
|
||
}
|
||
|
||
if (timer_index == timer_list.first_timer)
|
||
{
|
||
timer_ptr->next = timer_list.first_timer;
|
||
timer_list.first_timer = timer_ptr;
|
||
|
||
}
|
||
else
|
||
{
|
||
for (prev_timer = timer_list.first_timer;
|
||
prev_timer->next != timer_index;
|
||
prev_timer = prev_timer->next)
|
||
;
|
||
|
||
prev_timer->next = timer_ptr;
|
||
timer_ptr->next = timer_index;
|
||
}
|
||
|
||
gdb_notifier.timeout_valid = 0;
|
||
return timer_ptr->timer_id;
|
||
}
|
||
|
||
/* There is a chance that the creator of the timer wants to get rid of
|
||
it before it expires. */
|
||
void
|
||
delete_timer (int id)
|
||
{
|
||
struct gdb_timer *timer_ptr, *prev_timer = NULL;
|
||
|
||
/* Find the entry for the given timer. */
|
||
|
||
for (timer_ptr = timer_list.first_timer; timer_ptr != NULL;
|
||
timer_ptr = timer_ptr->next)
|
||
{
|
||
if (timer_ptr->timer_id == id)
|
||
break;
|
||
}
|
||
|
||
if (timer_ptr == NULL)
|
||
return;
|
||
/* Get rid of the timer in the timer list. */
|
||
if (timer_ptr == timer_list.first_timer)
|
||
timer_list.first_timer = timer_ptr->next;
|
||
else
|
||
{
|
||
for (prev_timer = timer_list.first_timer;
|
||
prev_timer->next != timer_ptr;
|
||
prev_timer = prev_timer->next)
|
||
;
|
||
prev_timer->next = timer_ptr->next;
|
||
}
|
||
delete timer_ptr;
|
||
|
||
gdb_notifier.timeout_valid = 0;
|
||
}
|
||
|
||
/* Convert a std::chrono duration to a struct timeval. */
|
||
|
||
template<typename Duration>
|
||
static struct timeval
|
||
duration_cast_timeval (const Duration &d)
|
||
{
|
||
using namespace std::chrono;
|
||
seconds sec = duration_cast<seconds> (d);
|
||
microseconds msec = duration_cast<microseconds> (d - sec);
|
||
|
||
struct timeval tv;
|
||
tv.tv_sec = sec.count ();
|
||
tv.tv_usec = msec.count ();
|
||
return tv;
|
||
}
|
||
|
||
/* Update the timeout for the select() or poll(). Returns true if the
|
||
timer has already expired, false otherwise. */
|
||
|
||
static int
|
||
update_wait_timeout (void)
|
||
{
|
||
if (timer_list.first_timer != NULL)
|
||
{
|
||
using namespace std::chrono;
|
||
steady_clock::time_point time_now = steady_clock::now ();
|
||
struct timeval timeout;
|
||
|
||
if (timer_list.first_timer->when < time_now)
|
||
{
|
||
/* It expired already. */
|
||
timeout.tv_sec = 0;
|
||
timeout.tv_usec = 0;
|
||
}
|
||
else
|
||
{
|
||
steady_clock::duration d = timer_list.first_timer->when - time_now;
|
||
timeout = duration_cast_timeval (d);
|
||
}
|
||
|
||
/* Update the timeout for select/ poll. */
|
||
if (use_poll)
|
||
{
|
||
#ifdef HAVE_POLL
|
||
gdb_notifier.poll_timeout = timeout.tv_sec * 1000;
|
||
#else
|
||
internal_error (__FILE__, __LINE__,
|
||
_("use_poll without HAVE_POLL"));
|
||
#endif /* HAVE_POLL */
|
||
}
|
||
else
|
||
{
|
||
gdb_notifier.select_timeout.tv_sec = timeout.tv_sec;
|
||
gdb_notifier.select_timeout.tv_usec = timeout.tv_usec;
|
||
}
|
||
gdb_notifier.timeout_valid = 1;
|
||
|
||
if (timer_list.first_timer->when < time_now)
|
||
return 1;
|
||
}
|
||
else
|
||
gdb_notifier.timeout_valid = 0;
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Check whether a timer in the timers queue is ready. If a timer is
|
||
ready, call its handler and return. Update the timeout for the
|
||
select() or poll() as well. Return 1 if an event was handled,
|
||
otherwise returns 0.*/
|
||
|
||
static int
|
||
poll_timers (void)
|
||
{
|
||
if (update_wait_timeout ())
|
||
{
|
||
struct gdb_timer *timer_ptr = timer_list.first_timer;
|
||
timer_handler_func *proc = timer_ptr->proc;
|
||
gdb_client_data client_data = timer_ptr->client_data;
|
||
|
||
/* Get rid of the timer from the beginning of the list. */
|
||
timer_list.first_timer = timer_ptr->next;
|
||
|
||
/* Delete the timer before calling the callback, not after, in
|
||
case the callback itself decides to try deleting the timer
|
||
too. */
|
||
delete timer_ptr;
|
||
|
||
/* Call the procedure associated with that timer. */
|
||
(proc) (client_data);
|
||
|
||
return 1;
|
||
}
|
||
|
||
return 0;
|
||
}
|