580 lines
14 KiB
C
580 lines
14 KiB
C
/* Generic serial interface functions.
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Copyright (C) 1992-1996, 1998-2001, 2003-2012 Free Software
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Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include "defs.h"
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#include "serial.h"
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#include "ser-base.h"
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#include "event-loop.h"
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#include "gdb_select.h"
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#include "gdb_string.h"
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#include "gdb_assert.h"
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#include <sys/time.h>
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#ifdef USE_WIN32API
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#include <winsock2.h>
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#endif
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static timer_handler_func push_event;
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static handler_func fd_event;
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/* Event handling for ASYNC serial code.
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At any time the SERIAL device either: has an empty FIFO and is
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waiting on a FD event; or has a non-empty FIFO/error condition and
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is constantly scheduling timer events.
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ASYNC only stops pestering its client when it is de-async'ed or it
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is told to go away. */
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/* Value of scb->async_state: */
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enum {
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/* >= 0 (TIMER_SCHEDULED) */
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/* The ID of the currently scheduled timer event. This state is
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rarely encountered. Timer events are one-off so as soon as the
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event is delivered the state is shanged to NOTHING_SCHEDULED. */
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FD_SCHEDULED = -1,
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/* The fd_event() handler is scheduled. It is called when ever the
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file descriptor becomes ready. */
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NOTHING_SCHEDULED = -2
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/* Either no task is scheduled (just going into ASYNC mode) or a
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timer event has just gone off and the current state has been
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forced into nothing scheduled. */
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};
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/* Identify and schedule the next ASYNC task based on scb->async_state
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and scb->buf* (the input FIFO). A state machine is used to avoid
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the need to make redundant calls into the event-loop - the next
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scheduled task is only changed when needed. */
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static void
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reschedule (struct serial *scb)
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{
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if (serial_is_async_p (scb))
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{
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int next_state;
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switch (scb->async_state)
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{
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case FD_SCHEDULED:
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if (scb->bufcnt == 0)
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next_state = FD_SCHEDULED;
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else
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{
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delete_file_handler (scb->fd);
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next_state = create_timer (0, push_event, scb);
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}
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break;
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case NOTHING_SCHEDULED:
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if (scb->bufcnt == 0)
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{
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add_file_handler (scb->fd, fd_event, scb);
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next_state = FD_SCHEDULED;
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}
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else
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{
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next_state = create_timer (0, push_event, scb);
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}
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break;
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default: /* TIMER SCHEDULED */
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if (scb->bufcnt == 0)
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{
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delete_timer (scb->async_state);
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add_file_handler (scb->fd, fd_event, scb);
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next_state = FD_SCHEDULED;
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}
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else
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next_state = scb->async_state;
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break;
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}
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if (serial_debug_p (scb))
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{
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switch (next_state)
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{
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case FD_SCHEDULED:
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if (scb->async_state != FD_SCHEDULED)
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fprintf_unfiltered (gdb_stdlog, "[fd%d->fd-scheduled]\n",
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scb->fd);
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break;
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default: /* TIMER SCHEDULED */
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if (scb->async_state == FD_SCHEDULED)
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fprintf_unfiltered (gdb_stdlog, "[fd%d->timer-scheduled]\n",
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scb->fd);
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break;
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}
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}
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scb->async_state = next_state;
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}
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}
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/* Run the SCB's async handle, and reschedule, if the handler doesn't
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close SCB. */
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static void
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run_async_handler_and_reschedule (struct serial *scb)
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{
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int is_open;
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/* Take a reference, so a serial_close call within the handler
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doesn't make SCB a dangling pointer. */
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serial_ref (scb);
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/* Run the handler. */
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scb->async_handler (scb, scb->async_context);
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is_open = serial_is_open (scb);
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serial_unref (scb);
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/* Get ready for more, if not already closed. */
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if (is_open)
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reschedule (scb);
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}
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/* FD_EVENT: This is scheduled when the input FIFO is empty (and there
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is no pending error). As soon as data arrives, it is read into the
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input FIFO and the client notified. The client should then drain
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the FIFO using readchar(). If the FIFO isn't immediatly emptied,
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push_event() is used to nag the client until it is. */
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static void
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fd_event (int error, void *context)
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{
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struct serial *scb = context;
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if (error != 0)
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{
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scb->bufcnt = SERIAL_ERROR;
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}
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else if (scb->bufcnt == 0)
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{
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/* Prime the input FIFO. The readchar() function is used to
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pull characters out of the buffer. See also
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generic_readchar(). */
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int nr;
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nr = scb->ops->read_prim (scb, BUFSIZ);
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if (nr == 0)
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{
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scb->bufcnt = SERIAL_EOF;
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}
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else if (nr > 0)
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{
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scb->bufcnt = nr;
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scb->bufp = scb->buf;
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}
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else
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{
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scb->bufcnt = SERIAL_ERROR;
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}
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}
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run_async_handler_and_reschedule (scb);
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}
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/* PUSH_EVENT: The input FIFO is non-empty (or there is a pending
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error). Nag the client until all the data has been read. In the
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case of errors, the client will need to close or de-async the
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device before naging stops. */
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static void
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push_event (void *context)
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{
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struct serial *scb = context;
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scb->async_state = NOTHING_SCHEDULED; /* Timers are one-off */
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run_async_handler_and_reschedule (scb);
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}
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/* Wait for input on scb, with timeout seconds. Returns 0 on success,
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otherwise SERIAL_TIMEOUT or SERIAL_ERROR. */
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static int
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ser_base_wait_for (struct serial *scb, int timeout)
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{
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while (1)
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{
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int numfds;
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struct timeval tv;
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fd_set readfds, exceptfds;
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/* NOTE: Some OS's can scramble the READFDS when the select()
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call fails (ex the kernel with Red Hat 5.2). Initialize all
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arguments before each call. */
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tv.tv_sec = timeout;
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tv.tv_usec = 0;
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FD_ZERO (&readfds);
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FD_ZERO (&exceptfds);
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FD_SET (scb->fd, &readfds);
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FD_SET (scb->fd, &exceptfds);
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if (timeout >= 0)
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numfds = gdb_select (scb->fd + 1, &readfds, 0, &exceptfds, &tv);
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else
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numfds = gdb_select (scb->fd + 1, &readfds, 0, &exceptfds, 0);
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if (numfds <= 0)
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{
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if (numfds == 0)
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return SERIAL_TIMEOUT;
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else if (errno == EINTR)
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continue;
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else
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return SERIAL_ERROR; /* Got an error from select or
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poll. */
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}
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return 0;
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}
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}
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/* Read any error output we might have. */
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static void
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ser_base_read_error_fd (struct serial *scb, int close_fd)
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{
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if (scb->error_fd != -1)
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{
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ssize_t s;
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char buf[GDB_MI_MSG_WIDTH + 1];
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for (;;)
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{
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char *current;
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char *newline;
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int to_read = GDB_MI_MSG_WIDTH;
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int num_bytes = -1;
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if (scb->ops->avail)
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num_bytes = (scb->ops->avail)(scb, scb->error_fd);
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if (num_bytes != -1)
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to_read = (num_bytes < to_read) ? num_bytes : to_read;
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if (to_read == 0)
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break;
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s = read (scb->error_fd, &buf, to_read);
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if ((s == -1) || (s == 0 && !close_fd))
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break;
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if (s == 0 && close_fd)
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{
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/* End of file. */
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close (scb->error_fd);
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scb->error_fd = -1;
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break;
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}
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/* In theory, embedded newlines are not a problem.
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But for MI, we want each output line to have just
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one newline for legibility. So output things
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in newline chunks. */
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gdb_assert (s > 0 && s <= GDB_MI_MSG_WIDTH);
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buf[s] = '\0';
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current = buf;
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while ((newline = strstr (current, "\n")) != NULL)
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{
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*newline = '\0';
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fputs_unfiltered (current, gdb_stderr);
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fputs_unfiltered ("\n", gdb_stderr);
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current = newline + 1;
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}
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fputs_unfiltered (current, gdb_stderr);
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}
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}
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}
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/* Read a character with user-specified timeout. TIMEOUT is number of seconds
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to wait, or -1 to wait forever. Use timeout of 0 to effect a poll. Returns
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char if successful. Returns -2 if timeout expired, EOF if line dropped
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dead, or -3 for any other error (see errno in that case). */
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static int
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do_ser_base_readchar (struct serial *scb, int timeout)
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{
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int status;
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int delta;
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/* We have to be able to keep the GUI alive here, so we break the
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original timeout into steps of 1 second, running the "keep the
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GUI alive" hook each time through the loop.
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Also, timeout = 0 means to poll, so we just set the delta to 0,
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so we will only go through the loop once. */
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delta = (timeout == 0 ? 0 : 1);
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while (1)
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{
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/* N.B. The UI may destroy our world (for instance by calling
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remote_stop,) in which case we want to get out of here as
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quickly as possible. It is not safe to touch scb, since
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someone else might have freed it. The
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deprecated_ui_loop_hook signals that we should exit by
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returning 1. */
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if (deprecated_ui_loop_hook)
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{
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if (deprecated_ui_loop_hook (0))
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return SERIAL_TIMEOUT;
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}
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status = ser_base_wait_for (scb, delta);
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if (timeout > 0)
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timeout -= delta;
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/* If we got a character or an error back from wait_for, then we can
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break from the loop before the timeout is completed. */
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if (status != SERIAL_TIMEOUT)
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break;
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/* If we have exhausted the original timeout, then generate
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a SERIAL_TIMEOUT, and pass it out of the loop. */
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else if (timeout == 0)
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{
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status = SERIAL_TIMEOUT;
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break;
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}
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/* We also need to check and consume the stderr because it could
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come before the stdout for some stubs. If we just sit and wait
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for stdout, we would hit a deadlock for that case. */
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ser_base_read_error_fd (scb, 0);
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}
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if (status < 0)
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return status;
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status = scb->ops->read_prim (scb, BUFSIZ);
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if (status <= 0)
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{
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if (status == 0)
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return SERIAL_EOF;
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else
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/* Got an error from read. */
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return SERIAL_ERROR;
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}
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scb->bufcnt = status;
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scb->bufcnt--;
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scb->bufp = scb->buf;
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return *scb->bufp++;
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}
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/* Perform operations common to both old and new readchar. */
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/* Return the next character from the input FIFO. If the FIFO is
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empty, call the SERIAL specific routine to try and read in more
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characters.
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Initially data from the input FIFO is returned (fd_event()
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pre-reads the input into that FIFO. Once that has been emptied,
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further data is obtained by polling the input FD using the device
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specific readchar() function. Note: reschedule() is called after
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every read. This is because there is no guarentee that the lower
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level fd_event() poll_event() code (which also calls reschedule())
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will be called. */
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int
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generic_readchar (struct serial *scb, int timeout,
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int (do_readchar) (struct serial *scb, int timeout))
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{
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int ch;
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if (scb->bufcnt > 0)
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{
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ch = *scb->bufp;
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scb->bufcnt--;
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scb->bufp++;
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}
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else if (scb->bufcnt < 0)
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{
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/* Some errors/eof are are sticky. */
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ch = scb->bufcnt;
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}
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else
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{
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ch = do_readchar (scb, timeout);
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if (ch < 0)
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{
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switch ((enum serial_rc) ch)
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{
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case SERIAL_EOF:
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case SERIAL_ERROR:
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/* Make the error/eof stick. */
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scb->bufcnt = ch;
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break;
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case SERIAL_TIMEOUT:
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scb->bufcnt = 0;
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break;
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}
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}
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}
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/* Read any error output we might have. */
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ser_base_read_error_fd (scb, 1);
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reschedule (scb);
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return ch;
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}
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int
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ser_base_readchar (struct serial *scb, int timeout)
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{
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return generic_readchar (scb, timeout, do_ser_base_readchar);
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}
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int
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ser_base_write (struct serial *scb, const char *str, int len)
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{
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int cc;
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while (len > 0)
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{
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cc = scb->ops->write_prim (scb, str, len);
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if (cc < 0)
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return 1;
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len -= cc;
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str += cc;
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}
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return 0;
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}
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int
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ser_base_flush_output (struct serial *scb)
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{
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return 0;
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}
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int
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ser_base_flush_input (struct serial *scb)
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{
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if (scb->bufcnt >= 0)
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{
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scb->bufcnt = 0;
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scb->bufp = scb->buf;
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return 0;
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}
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else
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return SERIAL_ERROR;
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}
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int
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ser_base_send_break (struct serial *scb)
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{
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return 0;
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}
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int
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ser_base_drain_output (struct serial *scb)
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{
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return 0;
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}
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void
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ser_base_raw (struct serial *scb)
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{
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return; /* Always in raw mode. */
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}
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serial_ttystate
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ser_base_get_tty_state (struct serial *scb)
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{
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/* Allocate a dummy. */
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return (serial_ttystate) XMALLOC (int);
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}
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serial_ttystate
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ser_base_copy_tty_state (struct serial *scb, serial_ttystate ttystate)
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{
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/* Allocate another dummy. */
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return (serial_ttystate) XMALLOC (int);
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}
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int
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ser_base_set_tty_state (struct serial *scb, serial_ttystate ttystate)
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{
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return 0;
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}
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int
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ser_base_noflush_set_tty_state (struct serial *scb,
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serial_ttystate new_ttystate,
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serial_ttystate old_ttystate)
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{
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return 0;
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}
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void
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ser_base_print_tty_state (struct serial *scb,
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serial_ttystate ttystate,
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struct ui_file *stream)
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{
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/* Nothing to print. */
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return;
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}
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int
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ser_base_setbaudrate (struct serial *scb, int rate)
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{
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return 0; /* Never fails! */
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}
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int
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ser_base_setstopbits (struct serial *scb, int num)
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{
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return 0; /* Never fails! */
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}
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/* Put the SERIAL device into/out-of ASYNC mode. */
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void
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ser_base_async (struct serial *scb,
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int async_p)
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{
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if (async_p)
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{
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/* Force a re-schedule. */
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scb->async_state = NOTHING_SCHEDULED;
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if (serial_debug_p (scb))
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fprintf_unfiltered (gdb_stdlog, "[fd%d->asynchronous]\n",
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scb->fd);
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reschedule (scb);
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}
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else
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{
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if (serial_debug_p (scb))
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fprintf_unfiltered (gdb_stdlog, "[fd%d->synchronous]\n",
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scb->fd);
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/* De-schedule whatever tasks are currently scheduled. */
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|
switch (scb->async_state)
|
|
{
|
|
case FD_SCHEDULED:
|
|
delete_file_handler (scb->fd);
|
|
break;
|
|
case NOTHING_SCHEDULED:
|
|
break;
|
|
default: /* TIMER SCHEDULED */
|
|
delete_timer (scb->async_state);
|
|
break;
|
|
}
|
|
}
|
|
}
|