| /* Generic serial interface functions. |
| |
| Copyright 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001, |
| 2003, 2004, 2005 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 2 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, write to the Free Software |
| Foundation, Inc., 59 Temple Place - Suite 330, |
| Boston, MA 02111-1307, USA. */ |
| |
| #include "defs.h" |
| #include "serial.h" |
| #include "ser-unix.h" |
| #include "event-loop.h" |
| |
| static timer_handler_func push_event; |
| static handler_func fd_event; |
| |
| /* Event handling for ASYNC serial code. |
| |
| At any time the SERIAL device either: has an empty FIFO and is |
| waiting on a FD event; or has a non-empty FIFO/error condition and |
| is constantly scheduling timer events. |
| |
| ASYNC only stops pestering its client when it is de-async'ed or it |
| is told to go away. */ |
| |
| /* Value of scb->async_state: */ |
| enum { |
| /* >= 0 (TIMER_SCHEDULED) */ |
| /* The ID of the currently scheduled timer event. This state is |
| rarely encountered. Timer events are one-off so as soon as the |
| event is delivered the state is shanged to NOTHING_SCHEDULED. */ |
| FD_SCHEDULED = -1, |
| /* The fd_event() handler is scheduled. It is called when ever the |
| file descriptor becomes ready. */ |
| NOTHING_SCHEDULED = -2 |
| /* Either no task is scheduled (just going into ASYNC mode) or a |
| timer event has just gone off and the current state has been |
| forced into nothing scheduled. */ |
| }; |
| |
| /* Identify and schedule the next ASYNC task based on scb->async_state |
| and scb->buf* (the input FIFO). A state machine is used to avoid |
| the need to make redundant calls into the event-loop - the next |
| scheduled task is only changed when needed. */ |
| |
| void |
| reschedule (struct serial *scb) |
| { |
| if (serial_is_async_p (scb)) |
| { |
| int next_state; |
| switch (scb->async_state) |
| { |
| case FD_SCHEDULED: |
| if (scb->bufcnt == 0) |
| next_state = FD_SCHEDULED; |
| else |
| { |
| delete_file_handler (scb->fd); |
| next_state = create_timer (0, push_event, scb); |
| } |
| break; |
| case NOTHING_SCHEDULED: |
| if (scb->bufcnt == 0) |
| { |
| add_file_handler (scb->fd, fd_event, scb); |
| next_state = FD_SCHEDULED; |
| } |
| else |
| { |
| next_state = create_timer (0, push_event, scb); |
| } |
| break; |
| default: /* TIMER SCHEDULED */ |
| if (scb->bufcnt == 0) |
| { |
| delete_timer (scb->async_state); |
| add_file_handler (scb->fd, fd_event, scb); |
| next_state = FD_SCHEDULED; |
| } |
| else |
| next_state = scb->async_state; |
| break; |
| } |
| if (serial_debug_p (scb)) |
| { |
| switch (next_state) |
| { |
| case FD_SCHEDULED: |
| if (scb->async_state != FD_SCHEDULED) |
| fprintf_unfiltered (gdb_stdlog, "[fd%d->fd-scheduled]\n", |
| scb->fd); |
| break; |
| default: /* TIMER SCHEDULED */ |
| if (scb->async_state == FD_SCHEDULED) |
| fprintf_unfiltered (gdb_stdlog, "[fd%d->timer-scheduled]\n", |
| scb->fd); |
| break; |
| } |
| } |
| scb->async_state = next_state; |
| } |
| } |
| |
| /* FD_EVENT: This is scheduled when the input FIFO is empty (and there |
| is no pending error). As soon as data arrives, it is read into the |
| input FIFO and the client notified. The client should then drain |
| the FIFO using readchar(). If the FIFO isn't immediatly emptied, |
| push_event() is used to nag the client until it is. */ |
| |
| static void |
| fd_event (int error, void *context) |
| { |
| struct serial *scb = context; |
| if (error != 0) |
| { |
| scb->bufcnt = SERIAL_ERROR; |
| } |
| else if (scb->bufcnt == 0) |
| { |
| /* Prime the input FIFO. The readchar() function is used to |
| pull characters out of the buffer. See also |
| generic_readchar(). */ |
| int nr; |
| do |
| { |
| nr = read (scb->fd, scb->buf, BUFSIZ); |
| } |
| while (nr == -1 && errno == EINTR); |
| if (nr == 0) |
| { |
| scb->bufcnt = SERIAL_EOF; |
| } |
| else if (nr > 0) |
| { |
| scb->bufcnt = nr; |
| scb->bufp = scb->buf; |
| } |
| else |
| { |
| scb->bufcnt = SERIAL_ERROR; |
| } |
| } |
| scb->async_handler (scb, scb->async_context); |
| reschedule (scb); |
| } |
| |
| /* PUSH_EVENT: The input FIFO is non-empty (or there is a pending |
| error). Nag the client until all the data has been read. In the |
| case of errors, the client will need to close or de-async the |
| device before naging stops. */ |
| |
| static void |
| push_event (void *context) |
| { |
| struct serial *scb = context; |
| scb->async_state = NOTHING_SCHEDULED; /* Timers are one-off */ |
| scb->async_handler (scb, scb->async_context); |
| /* re-schedule */ |
| reschedule (scb); |
| } |
| |
| int |
| ser_base_write (struct serial *scb, const char *str, int len) |
| { |
| int cc; |
| |
| while (len > 0) |
| { |
| cc = write (scb->fd, str, len); |
| |
| if (cc < 0) |
| return 1; |
| len -= cc; |
| str += cc; |
| } |
| return 0; |
| } |
| |
| int |
| ser_base_flush_output (struct serial *scb) |
| { |
| return 0; |
| } |
| |
| int |
| ser_base_flush_input (struct serial *scb) |
| { |
| if (scb->bufcnt >= 0) |
| { |
| scb->bufcnt = 0; |
| scb->bufp = scb->buf; |
| return 0; |
| } |
| else |
| return SERIAL_ERROR; |
| } |
| |
| int |
| ser_base_send_break (struct serial *scb) |
| { |
| return 0; |
| } |
| |
| int |
| ser_base_drain_output (struct serial *scb) |
| { |
| return 0; |
| } |
| |
| void |
| ser_base_raw (struct serial *scb) |
| { |
| return; /* Always in raw mode */ |
| } |
| |
| serial_ttystate |
| ser_base_get_tty_state (struct serial *scb) |
| { |
| /* allocate a dummy */ |
| return (serial_ttystate) XMALLOC (int); |
| } |
| |
| int |
| ser_base_set_tty_state (struct serial *scb, serial_ttystate ttystate) |
| { |
| return 0; |
| } |
| |
| int |
| ser_base_noflush_set_tty_state (struct serial *scb, |
| serial_ttystate new_ttystate, |
| serial_ttystate old_ttystate) |
| { |
| return 0; |
| } |
| |
| void |
| ser_base_print_tty_state (struct serial *scb, |
| serial_ttystate ttystate, |
| struct ui_file *stream) |
| { |
| /* Nothing to print. */ |
| return; |
| } |
| |
| int |
| ser_base_setbaudrate (struct serial *scb, int rate) |
| { |
| return 0; /* Never fails! */ |
| } |
| |
| int |
| ser_base_setstopbits (struct serial *scb, int num) |
| { |
| return 0; /* Never fails! */ |
| } |
| |
| /* Put the SERIAL device into/out-of ASYNC mode. */ |
| |
| void |
| ser_base_async (struct serial *scb, |
| int async_p) |
| { |
| if (async_p) |
| { |
| /* Force a re-schedule. */ |
| scb->async_state = NOTHING_SCHEDULED; |
| if (serial_debug_p (scb)) |
| fprintf_unfiltered (gdb_stdlog, "[fd%d->asynchronous]\n", |
| scb->fd); |
| reschedule (scb); |
| } |
| else |
| { |
| if (serial_debug_p (scb)) |
| fprintf_unfiltered (gdb_stdlog, "[fd%d->synchronous]\n", |
| scb->fd); |
| /* De-schedule whatever tasks are currently scheduled. */ |
| 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; |
| } |
| } |
| } |