2 * Empire - A multi-player, client/server Internet based war game.
3 * Copyright (C) 1986-2009, Dave Pare, Jeff Bailey, Thomas Ruschak,
4 * Ken Stevens, Steve McClure
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 * See files README, COPYING and CREDITS in the root of the source
23 * tree for related information and legal notices. It is expected
24 * that future projects/authors will amend these files as needed.
28 * io.c: Arrange for input and output on a file descriptor to be queued.
30 * Known contributors to this file:
33 * Ron Koenderink, 2009
37 * Arrange for input and output on a file descriptor
38 * to be queued. Provide main loop -- a mechanism for
39 * blocking across all registered file descriptors, and
40 * reading or writing when appropriate.
48 #include <sys/socket.h>
49 #include <sys/types.h>
53 #include "empthread.h"
62 struct ioqueue *input;
63 struct ioqueue *output;
66 struct timeval input_timeout;
75 io_open(int fd, int flags, int bufsize, struct timeval timeout)
79 flags = flags & (IO_READ | IO_WRITE | IO_NBLOCK | IO_NEWSOCK);
80 if ((flags & (IO_READ | IO_WRITE)) == 0)
82 iop = malloc(sizeof(struct iop));
89 iop->input_timeout = timeout;
90 iop->bufsize = bufsize;
91 if ((flags & IO_READ) && (flags & IO_NEWSOCK) == 0)
92 iop->input = ioq_create(bufsize);
93 if ((flags & IO_WRITE) && (flags & IO_NEWSOCK) == 0)
94 iop->output = ioq_create(bufsize);
95 if (flags & IO_NBLOCK)
96 io_noblocking(iop, 1); /* FIXME check success */
102 io_close(struct iop *iop)
106 ioq_destroy(iop->input);
107 if (iop->output != 0)
108 ioq_destroy(iop->output);
109 (void)close(iop->fd);
114 * Return number of bytes read on success, zero on timeout, early
115 * wakeup or EOF, -1 on error, with errno set appropriately. In
116 * particular, return -1 with errno set to EAGAIN or EWOULDBLOCK when
117 * no data is available for non-blocking input (WAITFORINPUT false).
118 * Use io_eof() to distinguish timeout and early wakeup from EOF.
121 io_input(struct iop *iop, int waitforinput)
123 char buf[IO_BUFSIZE];
131 if ((iop->flags & IO_READ) == 0) {
135 /* IOP is markes as in error. */
136 if (iop->flags & IO_ERROR) {
140 /* Wait for the file to have input. */
142 res = empth_select(iop->fd, EMPTH_FD_READ, &iop->input_timeout);
144 iop->flags |= IO_ERROR;
150 /* Do the actual read. */
151 cc = read(iop->fd, buf, sizeof(buf));
153 if (errno != EAGAIN && errno != EWOULDBLOCK)
154 /* Some form of file error occurred... */
155 iop->flags |= IO_ERROR;
161 iop->flags |= IO_EOF;
165 /* Append the input to the IOQ. */
166 ioq_append(iop->input, buf, cc);
171 io_inputwaiting(struct iop *iop)
173 return ioq_qsize(iop->input);
177 io_outputwaiting(struct iop *iop)
179 return ioq_qsize(iop->output);
183 io_output(struct iop *iop, int waitforoutput)
185 struct iovec iov[16];
193 /* If there is no output waiting. */
194 if (!io_outputwaiting(iop))
197 /* If the iop is not write enabled. */
198 if ((iop->flags & IO_WRITE) == 0)
201 /* If the io is marked as in error... */
202 if (iop->flags & IO_ERROR)
205 /* make the iov point to the data in the queue. */
206 /* I.E., each of the elements in the queue. */
207 /* returns the number of elements in the iov. */
208 n = ioq_makeiov(iop->output, iov, IO_BUFSIZE);
214 /* wait for the file to be output ready. */
215 if (waitforoutput != IO_NOWAIT) {
216 /* This waits for the file to be ready for writing, */
217 /* and lets other threads run. */
218 empth_select(iop->fd, EMPTH_FD_WRITE, NULL);
221 /* Do the actual write. */
222 cc = writev(iop->fd, iov, n);
224 /* if it failed.... */
226 /* Hmm, it would block. file is opened noblock, soooooo.. */
227 if (errno == EAGAIN || errno == EWOULDBLOCK) {
228 /* If there are remaining bytes, set the IO as remaining.. */
229 remain = ioq_qsize(iop->output);
232 iop->flags |= IO_ERROR;
236 /* If no bytes were written, something happened.. Like an EOF. */
238 iop->flags |= IO_EOF;
242 /* Remove the number of written bytes from the queue. */
243 ioq_dequeue(iop->output, cc);
249 io_peek(struct iop *iop, char *buf, int nbytes)
251 if ((iop->flags & IO_READ) == 0)
253 return ioq_peek(iop->input, buf, nbytes);
257 io_read(struct iop *iop, char *buf, int nbytes)
261 if ((iop->flags & IO_READ) == 0)
263 cc = ioq_peek(iop->input, buf, nbytes);
265 ioq_dequeue(iop->input, cc);
270 io_write(struct iop *iop, char *buf, int nbytes, int doWait)
277 if ((iop->flags & IO_WRITE) == 0)
279 ioq_append(iop->output, buf, nbytes);
280 len = ioq_qsize(iop->output);
281 if (len > iop->bufsize) {
285 /* only try a write every BUFSIZE characters */
286 if (((len - nbytes) % iop->bufsize) < (len % iop->bufsize))
287 io_output(iop, IO_NOWAIT);
294 io_output_all(struct iop *iop)
301 * Mustn't block a player thread while update is pending, or else
302 * a malicous player could delay the update indefinitely
304 while ((n = io_output(iop, IO_NOWAIT)) > 0 && !play_wrlock_wanted)
305 empth_select(iop->fd, EMPTH_FD_WRITE, NULL);
311 io_gets(struct iop *iop, char *buf, int nbytes)
313 if ((iop->flags & IO_READ) == 0)
315 return ioq_gets(iop->input, buf, nbytes);
319 io_puts(struct iop *iop, char *buf)
321 if ((iop->flags & IO_WRITE) == 0)
323 return ioq_puts(iop->output, buf);
327 io_shutdown(struct iop *iop, int flags)
329 flags &= (IO_READ | IO_WRITE);
330 if ((iop->flags & flags) != flags)
332 if (flags & IO_READ) {
333 shutdown(iop->fd, 0);
334 ioq_drain(iop->input);
336 if (flags & IO_WRITE) {
337 shutdown(iop->fd, 1);
338 ioq_drain(iop->output);
344 io_noblocking(struct iop *iop, int value)
348 flags = fcntl(iop->fd, F_GETFL, 0);
352 flags &= ~O_NONBLOCK;
355 if (fcntl(iop->fd, F_SETFL, flags) < 0)
358 iop->flags &= ~IO_NBLOCK;
360 iop->flags |= IO_NBLOCK;
365 io_error(struct iop *iop)
367 return iop->flags & IO_ERROR;
371 io_eof(struct iop *iop)
373 return iop->flags & IO_EOF;
377 io_fileno(struct iop *iop)