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Re: HAVE_POLL is not enough - RFA
- To: ac131313 at cygnus dot com (Andrew Cagney)
- Subject: Re: HAVE_POLL is not enough - RFA
- From: "Philippe De Muyter" <phdm at macqel dot be>
- Date: Tue, 21 Mar 100 16:59:54 +0100 (CET)
- Cc: ezannoni at cygnus dot com, gdb-patches at sourceware dot cygnus dot com
Andrew Cagney wrote :
> if (use_poll)
> {
> #if HAVE_POLL
> ...
> #else
> internal_error (...);
> #endif
> }
> else
> {
> }
I have done that. OK to commit ?
Tue Mar 21 16:49:38 2000 Philippe De Muyter <phdm@macqel.be>
* event-loop.c (sys/types.h): File now included unconditionally.
(use_poll): New variable, initialized to HAVE_POLL.
(gdb_notifier): poll- and select-versions merged.
(add_file_handler): If HAVE_POLL, check whether poll is usable,
and reset `use_poll' if not.
(create_file_handler): Select poll- or select-version according to
`use_poll'.
(delete_file_handler, handle_file_event): Likewise.
(gdb_wait_for_event, poll_timers): Likewise.
Index: gdb/event-loop.c
===================================================================
RCS file: /cvs/src/src/gdb/event-loop.c,v
retrieving revision 1.4
diff -u -p -r1.4 event-loop.c
--- event-loop.c 2000/03/20 19:59:38 1.4
+++ event-loop.c 2000/03/21 15:39:29
@@ -25,10 +25,9 @@
#include "event-top.h"
#ifdef HAVE_POLL
#include <poll.h>
-#else
+#endif
#include <sys/types.h>
#include <string.h>
-#endif
#include <errno.h>
#include <setjmp.h>
#include <sys/time.h>
@@ -166,36 +165,21 @@ event_queue;
/* As of 1999-04-30 only the input file descriptor is registered with the
event loop. */
-#ifdef HAVE_POLL
-/* Poll based implementation of the notifier. */
+/* Do we use poll or select ? */
+static unsigned char use_poll = HAVE_POLL;
static struct
{
/* Ptr to head of file handler list. */
file_handler *first_file_handler;
+#ifdef HAVE_POLL
/* Ptr to array of pollfd structures. */
struct pollfd *poll_fds;
- /* Number of file descriptors to monitor. */
- int num_fds;
-
/* Timeout in milliseconds for calls to poll(). */
- int timeout;
-
- /* Flag to tell whether the timeout value shuld be used. */
- int timeout_valid;
- }
-gdb_notifier;
-
-#else /* ! HAVE_POLL */
-
-/* Select based implementation of the notifier. */
-
-static struct
- {
- /* Ptr to head of file handler list. */
- file_handler *first_file_handler;
+ 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. */
@@ -204,19 +188,18 @@ static struct
/* What file descriptors were found ready by select. */
fd_set ready_masks[3];
- /* Number of valid bits (highest fd value + 1). */
+ /* 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 timeout;
+ struct timeval select_timeout;
- /* Flag to tell whether the timeout struct should be used. */
+ /* Flag to tell whether the timeout should be used. */
int timeout_valid;
}
gdb_notifier;
-#endif /* HAVE_POLL */
-
/* Structure associated with a timer. PROC will be executed at the
first occasion after WHEN. */
struct gdb_timer
@@ -384,7 +367,7 @@ process_event (void)
}
free ((char *) event_ptr);
- /* Now call the procedure associted with the event. */
+ /* Now call the procedure associated with the event. */
(*proc) (fd);
return 1;
}
@@ -473,10 +456,30 @@ void
add_file_handler (int fd, handler_func * proc, gdb_client_data client_data)
{
#ifdef HAVE_POLL
- create_file_handler (fd, POLLIN, proc, client_data);
+ struct pollfd fds;
+#endif
+
+ if (use_poll)
+ {
+#ifdef HAVE_POLL
+ fds.fd = fd;
+ fds.events = POLLIN;
+ if (poll (&fds, 1, 0) == 1 && (fds.revents & POLLNVAL))
+ use_poll = 0;
#else
- create_file_handler (fd, GDB_READABLE | GDB_EXCEPTION, proc, client_data);
+ internal_error ("event-loop.c : use_poll without HAVE_POLL");
+#endif /* HAVE_POLL */
+ }
+ if (use_poll)
+ {
+#ifdef HAVE_POLL
+ create_file_handler (fd, POLLIN, proc, client_data);
+#else
+ internal_error ("event-loop.c : use_poll without HAVE_POLL");
#endif
+ }
+ else
+ create_file_handler (fd, GDB_READABLE | GDB_EXCEPTION, proc, client_data);
}
/* Add a file handler/descriptor to the list of descriptors we are
@@ -512,48 +515,49 @@ create_file_handler (int fd, int mask, h
file_ptr->ready_mask = 0;
file_ptr->next_file = gdb_notifier.first_file_handler;
gdb_notifier.first_file_handler = file_ptr;
-#ifdef HAVE_POLL
- gdb_notifier.num_fds++;
-#endif
}
file_ptr->proc = proc;
file_ptr->client_data = client_data;
file_ptr->mask = mask;
+ if (use_poll)
+ {
#ifdef HAVE_POLL
-
- if (gdb_notifier.poll_fds)
- gdb_notifier.poll_fds =
- (struct pollfd *) realloc (gdb_notifier.poll_fds,
- (gdb_notifier.num_fds) * sizeof (struct pollfd));
- else
- gdb_notifier.poll_fds =
- (struct pollfd *) xmalloc (sizeof (struct pollfd));
- (gdb_notifier.poll_fds + gdb_notifier.num_fds - 1)->fd = fd;
- (gdb_notifier.poll_fds + gdb_notifier.num_fds - 1)->events = mask;
- (gdb_notifier.poll_fds + gdb_notifier.num_fds - 1)->revents = 0;
-
-#else /* ! HAVE_POLL */
-
- 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]);
+ gdb_notifier.num_fds++;
+ if (gdb_notifier.poll_fds)
+ gdb_notifier.poll_fds =
+ (struct pollfd *) realloc (gdb_notifier.poll_fds,
+ (gdb_notifier.num_fds) * sizeof (struct pollfd));
+ else
+ gdb_notifier.poll_fds =
+ (struct pollfd *) xmalloc (sizeof (struct pollfd));
+ (gdb_notifier.poll_fds + gdb_notifier.num_fds - 1)->fd = fd;
+ (gdb_notifier.poll_fds + gdb_notifier.num_fds - 1)->events = mask;
+ (gdb_notifier.poll_fds + gdb_notifier.num_fds - 1)->revents = 0;
+#else
+ internal_error ("event-loop.c : use_poll without HAVE_POLL");
+#endif /* HAVE_POLL */
+ }
else
- FD_CLR (fd, &gdb_notifier.check_masks[1]);
+ {
+ if (mask & GDB_READABLE)
+ FD_SET (fd, &gdb_notifier.check_masks[0]);
+ else
+ FD_CLR (fd, &gdb_notifier.check_masks[0]);
- if (mask & GDB_EXCEPTION)
- FD_SET (fd, &gdb_notifier.check_masks[2]);
- else
- FD_CLR (fd, &gdb_notifier.check_masks[2]);
+ if (mask & GDB_WRITABLE)
+ FD_SET (fd, &gdb_notifier.check_masks[1]);
+ else
+ FD_CLR (fd, &gdb_notifier.check_masks[1]);
- if (gdb_notifier.num_fds <= fd)
- gdb_notifier.num_fds = fd + 1;
+ if (mask & GDB_EXCEPTION)
+ FD_SET (fd, &gdb_notifier.check_masks[2]);
+ else
+ FD_CLR (fd, &gdb_notifier.check_masks[2]);
-#endif /* HAVE_POLL */
+ if (gdb_notifier.num_fds <= fd)
+ gdb_notifier.num_fds = fd + 1;
+ }
}
/* Remove the file descriptor FD from the list of monitored fd's:
@@ -580,51 +584,56 @@ delete_file_handler (int fd)
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. */
+ /* 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++)
- {
- if ((gdb_notifier.poll_fds + i)->fd != fd)
+ for (i = 0, j = 0; i < gdb_notifier.num_fds; i++)
{
- (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++;
+ 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++;
+ }
}
+ free (gdb_notifier.poll_fds);
+ gdb_notifier.poll_fds = new_poll_fds;
+ gdb_notifier.num_fds--;
+#else
+ internal_error ("event-loop.c : use_poll without HAVE_POLL");
+#endif /* HAVE_POLL */
}
- free (gdb_notifier.poll_fds);
- gdb_notifier.poll_fds = new_poll_fds;
- gdb_notifier.num_fds--;
-
-#else /* ! HAVE_POLL */
-
- 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]);
+ 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. */
+ /* 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 + 1) == gdb_notifier.num_fds)
{
- 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--;
+ 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;
}
- gdb_notifier.num_fds = i;
}
-#endif /* HAVE_POLL */
/* Deactivate the file descriptor, by clearing its mask,
so that it will not fire again. */
@@ -676,36 +685,43 @@ handle_file_event (int event_file_desc)
/* See if the desired events (mask) match the received
events (ready_mask). */
-#ifdef HAVE_POLL
- error_mask = POLLHUP | POLLERR | POLLNVAL;
- mask = (file_ptr->ready_mask & file_ptr->mask) |
- (file_ptr->ready_mask & error_mask);
- error_mask_returned = mask & error_mask;
-
- if (error_mask_returned != 0)
+ if (use_poll)
{
- /* Work in progress. We may need to tell somebody what
- kind of error we had. */
- if (error_mask_returned & POLLHUP)
- printf_unfiltered ("Hangup detected on fd %d\n", file_ptr->fd);
- if (error_mask_returned & POLLERR)
- printf_unfiltered ("Error detected on fd %d\n", file_ptr->fd);
- if (error_mask_returned & POLLNVAL)
- printf_unfiltered ("Invalid or non-`poll'able fd %d\n", file_ptr->fd);
- file_ptr->error = 1;
+#ifdef HAVE_POLL
+ error_mask = POLLHUP | POLLERR | POLLNVAL;
+ mask = (file_ptr->ready_mask & file_ptr->mask) |
+ (file_ptr->ready_mask & error_mask);
+ error_mask_returned = mask & error_mask;
+
+ if (error_mask_returned != 0)
+ {
+ /* Work in progress. We may need to tell somebody what
+ kind of error we had. */
+ if (error_mask_returned & POLLHUP)
+ printf_unfiltered ("Hangup detected on fd %d\n", file_ptr->fd);
+ if (error_mask_returned & POLLERR)
+ printf_unfiltered ("Error detected on fd %d\n", file_ptr->fd);
+ if (error_mask_returned & POLLNVAL)
+ printf_unfiltered ("Invalid or non-`poll'able fd %d\n", file_ptr->fd);
+ file_ptr->error = 1;
+ }
+ else
+ file_ptr->error = 0;
+#else
+ internal_error ("event-loop.c : use_poll without HAVE_POLL");
+#endif /* HAVE_POLL */
}
else
- file_ptr->error = 0;
-#else /* ! HAVE_POLL */
- if (file_ptr->ready_mask & GDB_EXCEPTION)
{
- printf_unfiltered ("Exception condition detected on fd %d\n", file_ptr->fd);
- file_ptr->error = 1;
+ if (file_ptr->ready_mask & GDB_EXCEPTION)
+ {
+ printf_unfiltered ("Exception condition detected on fd %d\n", file_ptr->fd);
+ file_ptr->error = 1;
+ }
+ else
+ file_ptr->error = 0;
+ mask = file_ptr->ready_mask & file_ptr->mask;
}
- else
- file_ptr->error = 0;
- mask = file_ptr->ready_mask & file_ptr->mask;
-#endif /* HAVE_POLL */
/* Clear the received events for next time around. */
file_ptr->ready_mask = 0;
@@ -731,9 +747,7 @@ gdb_wait_for_event (void)
file_handler *file_ptr;
gdb_event *file_event_ptr;
int num_found = 0;
-#ifdef HAVE_POLL
int i;
-#endif
/* Make sure all output is done before getting another event. */
gdb_flush (gdb_stdout);
@@ -742,108 +756,114 @@ gdb_wait_for_event (void)
if (gdb_notifier.num_fds == 0)
return -1;
+ if (use_poll)
+ {
#ifdef HAVE_POLL
- num_found =
- poll (gdb_notifier.poll_fds,
- (unsigned long) gdb_notifier.num_fds,
- gdb_notifier.timeout_valid ? gdb_notifier.timeout : -1);
-
- /* Don't print anything if we get out of poll because of a
- signal. */
- if (num_found == -1 && errno != EINTR)
- perror_with_name ("Poll");
-
-#else /* ! HAVE_POLL */
-
- gdb_notifier.ready_masks[0] = gdb_notifier.check_masks[0];
- gdb_notifier.ready_masks[1] = gdb_notifier.check_masks[1];
- gdb_notifier.ready_masks[2] = gdb_notifier.check_masks[2];
-
- num_found = select (gdb_notifier.num_fds,
- & gdb_notifier.ready_masks[0],
- & gdb_notifier.ready_masks[1],
- & gdb_notifier.ready_masks[2],
- gdb_notifier.timeout_valid
- ? &gdb_notifier.timeout : NULL);
-
- /* Clear the masks after an error from select. */
- if (num_found == -1)
- {
- FD_ZERO (&gdb_notifier.ready_masks[0]);
- FD_ZERO (&gdb_notifier.ready_masks[1]);
- FD_ZERO (&gdb_notifier.ready_masks[2]);
- /* Dont print anything is we got a signal, let gdb handle it. */
- if (errno != EINTR)
- perror_with_name ("Select");
- }
+ num_found =
+ poll (gdb_notifier.poll_fds,
+ (unsigned long) gdb_notifier.num_fds,
+ gdb_notifier.timeout_valid ? gdb_notifier.poll_timeout : -1);
+
+ /* Don't print anything if we get out of poll because of a
+ signal. */
+ if (num_found == -1 && errno != EINTR)
+ perror_with_name ("Poll");
+#else
+ internal_error ("event-loop.c : use_poll without HAVE_POLL");
#endif /* HAVE_POLL */
+ }
+ else
+ {
+ gdb_notifier.ready_masks[0] = gdb_notifier.check_masks[0];
+ gdb_notifier.ready_masks[1] = gdb_notifier.check_masks[1];
+ gdb_notifier.ready_masks[2] = gdb_notifier.check_masks[2];
+ num_found = select (gdb_notifier.num_fds,
+ & gdb_notifier.ready_masks[0],
+ & gdb_notifier.ready_masks[1],
+ & gdb_notifier.ready_masks[2],
+ gdb_notifier.timeout_valid
+ ? &gdb_notifier.select_timeout : NULL);
+ /* Clear the masks after an error from select. */
+ if (num_found == -1)
+ {
+ FD_ZERO (&gdb_notifier.ready_masks[0]);
+ FD_ZERO (&gdb_notifier.ready_masks[1]);
+ FD_ZERO (&gdb_notifier.ready_masks[2]);
+ /* Dont print anything is we got a signal, let gdb handle it. */
+ if (errno != EINTR)
+ perror_with_name ("Select");
+ }
+ }
+
/* Enqueue all detected file events. */
+ if (use_poll)
+ {
#ifdef HAVE_POLL
+ for (i = 0; (i < gdb_notifier.num_fds) && (num_found > 0); i++)
+ {
+ if ((gdb_notifier.poll_fds + i)->revents)
+ num_found--;
+ else
+ continue;
- for (i = 0; (i < gdb_notifier.num_fds) && (num_found > 0); i++)
- {
- if ((gdb_notifier.poll_fds + i)->revents)
- num_found--;
- else
- continue;
+ for (file_ptr = gdb_notifier.first_file_handler;
+ file_ptr != NULL;
+ file_ptr = file_ptr->next_file)
+ {
+ if (file_ptr->fd == (gdb_notifier.poll_fds + i)->fd)
+ break;
+ }
+
+ if (file_ptr)
+ {
+ /* Enqueue an event only if this is still a new event for
+ this fd. */
+ if (file_ptr->ready_mask == 0)
+ {
+ file_event_ptr = create_file_event (file_ptr->fd);
+ async_queue_event (file_event_ptr, TAIL);
+ }
+ }
+ file_ptr->ready_mask = (gdb_notifier.poll_fds + i)->revents;
+ }
+#else
+ internal_error ("event-loop.c : use_poll without HAVE_POLL");
+#endif /* HAVE_POLL */
+ }
+ else
+ {
for (file_ptr = gdb_notifier.first_file_handler;
- file_ptr != NULL;
+ (file_ptr != NULL) && (num_found > 0);
file_ptr = file_ptr->next_file)
{
- if (file_ptr->fd == (gdb_notifier.poll_fds + i)->fd)
- break;
- }
+ int mask = 0;
- if (file_ptr)
- {
+ if (FD_ISSET (file_ptr->fd, &gdb_notifier.ready_masks[0]))
+ mask |= GDB_READABLE;
+ if (FD_ISSET (file_ptr->fd, &gdb_notifier.ready_masks[1]))
+ mask |= GDB_WRITABLE;
+ if (FD_ISSET (file_ptr->fd, &gdb_notifier.ready_masks[2]))
+ mask |= GDB_EXCEPTION;
+
+ if (!mask)
+ continue;
+ else
+ num_found--;
+
/* Enqueue an event only if this is still a new event for
this fd. */
+
if (file_ptr->ready_mask == 0)
{
file_event_ptr = create_file_event (file_ptr->fd);
async_queue_event (file_event_ptr, TAIL);
}
+ file_ptr->ready_mask = mask;
}
-
- file_ptr->ready_mask = (gdb_notifier.poll_fds + i)->revents;
}
-
-#else /* ! HAVE_POLL */
-
- for (file_ptr = gdb_notifier.first_file_handler;
- (file_ptr != NULL) && (num_found > 0);
- file_ptr = file_ptr->next_file)
- {
- int mask = 0;
-
- if (FD_ISSET (file_ptr->fd, &gdb_notifier.ready_masks[0]))
- mask |= GDB_READABLE;
- if (FD_ISSET (file_ptr->fd, &gdb_notifier.ready_masks[1]))
- mask |= GDB_WRITABLE;
- if (FD_ISSET (file_ptr->fd, &gdb_notifier.ready_masks[2]))
- mask |= GDB_EXCEPTION;
-
- if (!mask)
- continue;
- else
- num_found--;
-
- /* Enqueue an event only if this is still a new event for
- this fd. */
-
- if (file_ptr->ready_mask == 0)
- {
- file_event_ptr = create_file_event (file_ptr->fd);
- async_queue_event (file_event_ptr, TAIL);
- }
- file_ptr->ready_mask = mask;
- }
-
-#endif /* HAVE_POLL */
-
return 0;
}
@@ -1125,12 +1145,19 @@ poll_timers (void)
/* Now we need to update the timeout for select/ poll, because we
don't want to sit there while this timer is expiring. */
+ if (use_poll)
+ {
#ifdef HAVE_POLL
- gdb_notifier.timeout = delta.tv_sec * 1000;
+ gdb_notifier.poll_timeout = delta.tv_sec * 1000;
#else
- gdb_notifier.timeout.tv_sec = delta.tv_sec;
- gdb_notifier.timeout.tv_usec = delta.tv_usec;
-#endif
+ internal_error ("event-loop.c : use_poll without HAVE_POLL");
+#endif /* HAVE_POLL */
+ }
+ else
+ {
+ gdb_notifier.select_timeout.tv_sec = delta.tv_sec;
+ gdb_notifier.select_timeout.tv_usec = delta.tv_usec;
+ }
gdb_notifier.timeout_valid = 1;
}
else