aboutsummaryrefslogtreecommitdiff
path: root/sim/common/dv-sockser.c
blob: 34d17fd2b41bfb9c23fc4bc100a5cd676512ec87 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
/* Serial port emulation using sockets.
   Copyright (C) 1998, 2007, 2008 Free Software Foundation, Inc.
   Contributed by Cygnus Solutions.

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/>.  */

/* FIXME: will obviously need to evolve.
   - connectionless sockets might be more appropriate.  */

#include "sim-main.h"

#ifdef HAVE_STRING_H
#include <string.h>
#else
#ifdef HAVE_STRINGS_H
#include <strings.h>
#endif
#endif
#include <signal.h>
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#include <errno.h>
#include <sys/types.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <sys/socket.h>

#ifndef __CYGWIN32__
#include <netinet/tcp.h>
#endif

#include "sim-assert.h"
#include "sim-options.h"

#include "dv-sockser.h"

/* Get definitions for both O_NONBLOCK and O_NDELAY.  */

#ifndef O_NDELAY
#ifdef FNDELAY
#define O_NDELAY FNDELAY
#else /* ! defined (FNDELAY) */
#define O_NDELAY 0
#endif /* ! defined (FNDELAY) */
#endif /* ! defined (O_NDELAY) */

#ifndef O_NONBLOCK
#ifdef FNBLOCK
#define O_NONBLOCK FNBLOCK
#else /* ! defined (FNBLOCK) */
#define O_NONBLOCK 0
#endif /* ! defined (FNBLOCK) */
#endif /* ! defined (O_NONBLOCK) */


/* Compromise between eating cpu and properly busy-waiting.
   One could have an option to set this but for now that seems
   like featuritis.  */
#define DEFAULT_TIMEOUT 1000 /* microseconds */

/* FIXME: These should allocated at run time and kept with other simulator
   state (duh...).  Later.  */
const char * sockser_addr = NULL;
/* Timeout in microseconds during status flag computation.
   Setting this to zero achieves proper busy wait semantics but eats cpu.  */
static unsigned int sockser_timeout = DEFAULT_TIMEOUT;
static int sockser_listen_fd = -1;
static int sockser_fd = -1;

/* FIXME: use tree properties when they're ready.  */

typedef enum {
  OPTION_ADDR = OPTION_START
} SOCKSER_OPTIONS;

static DECLARE_OPTION_HANDLER (sockser_option_handler);

static const OPTION sockser_options[] =
{
  { { "sockser-addr", required_argument, NULL, OPTION_ADDR },
      '\0', "SOCKET ADDRESS", "Set serial emulation socket address",
      sockser_option_handler },
  { { NULL, no_argument, NULL, 0 }, '\0', NULL, NULL, NULL }
};

static SIM_RC
sockser_option_handler (SIM_DESC sd, sim_cpu *cpu, int opt,
			char *arg, int is_command)
{
  switch (opt)
    {
    case OPTION_ADDR :
      sockser_addr = arg;
      break;
    }

  return SIM_RC_OK;
}

static SIM_RC
dv_sockser_init (SIM_DESC sd)
{
  struct hostent *hostent;
  struct sockaddr_in sockaddr;
  char hostname[100];
  const char *port_str;
  int tmp,port;

  if (STATE_ENVIRONMENT (sd) != OPERATING_ENVIRONMENT
      || sockser_addr == NULL)
    return SIM_RC_OK;

  if (*sockser_addr == '/')
    {
      /* support for these can come later */
      sim_io_eprintf (sd, "sockser init: unix domain sockets not supported: `%s'\n",
		      sockser_addr);
      return SIM_RC_FAIL;
    }

  port_str = strchr (sockser_addr, ':');
  if (!port_str)
    {
      sim_io_eprintf (sd, "sockser init: missing port number: `%s'\n",
		      sockser_addr);
      return SIM_RC_FAIL;
    }
  tmp = port_str - sockser_addr;
  if (tmp >= sizeof hostname)
    tmp = sizeof (hostname) - 1;
  strncpy (hostname, sockser_addr, tmp);
  hostname[tmp] = '\000';
  port = atoi (port_str + 1);

  hostent = gethostbyname (hostname);
  if (! hostent)
    {
      sim_io_eprintf (sd, "sockser init: unknown host: %s\n",
		      hostname);
      return SIM_RC_FAIL;
    }

  sockser_listen_fd = socket (PF_INET, SOCK_STREAM, 0);
  if (sockser_listen_fd < 0)
    {
      sim_io_eprintf (sd, "sockser init: unable to get socket: %s\n",
		      strerror (errno));
      return SIM_RC_FAIL;
    }

  sockaddr.sin_family = PF_INET;
  sockaddr.sin_port = htons(port);
  memcpy (&sockaddr.sin_addr.s_addr, hostent->h_addr,
	  sizeof (struct in_addr));

  tmp = 1;
  if (setsockopt (sockser_listen_fd, SOL_SOCKET, SO_REUSEADDR, (void*)& tmp, sizeof(tmp)) < 0)
    {
      sim_io_eprintf (sd, "sockser init: unable to set SO_REUSEADDR: %s\n",
		      strerror (errno));
    }
  if (bind (sockser_listen_fd, (struct sockaddr *) &sockaddr, sizeof (sockaddr)) < 0)
    {
      sim_io_eprintf (sd, "sockser init: unable to bind socket address: %s\n",
		      strerror (errno));
      close (sockser_listen_fd);
      sockser_listen_fd = -1;
      return SIM_RC_FAIL;
    }
  if (listen (sockser_listen_fd, 1) < 0)
    {
      sim_io_eprintf (sd, "sockser init: unable to set up listener: %s\n",
		      strerror (errno));
      close (sockser_listen_fd);
      sockser_listen_fd = -1;
      return SIM_RC_OK;
    }

  /* Handle writes to missing client -> SIGPIPE.
     ??? Need a central signal management module.  */
  {
    RETSIGTYPE (*orig) ();
    orig = signal (SIGPIPE, SIG_IGN);
    /* If a handler is already set up, don't mess with it.  */
    if (orig != SIG_DFL && orig != SIG_IGN)
      signal (SIGPIPE, orig);
  }

  return SIM_RC_OK;
}

static void
dv_sockser_uninstall (SIM_DESC sd)
{
  if (sockser_listen_fd != -1)
    {
      close (sockser_listen_fd);
      sockser_listen_fd = -1;
    }
  if (sockser_fd != -1)
    {
      close (sockser_fd);
      sockser_fd = -1;
    }
}

SIM_RC
dv_sockser_install (SIM_DESC sd)
{
  SIM_ASSERT (STATE_MAGIC (sd) == SIM_MAGIC_NUMBER);
  if (sim_add_option_table (sd, NULL, sockser_options) != SIM_RC_OK)
    return SIM_RC_FAIL;
  sim_module_add_init_fn (sd, dv_sockser_init);
  sim_module_add_uninstall_fn (sd, dv_sockser_uninstall);
  return SIM_RC_OK;
}

static int
connected_p (SIM_DESC sd)
{
  int numfds,flags;
  struct timeval tv;
  fd_set readfds;
  struct sockaddr sockaddr;
  int addrlen;

  if (sockser_listen_fd == -1)
    return 0;

  if (sockser_fd >= 0)
    {
      /* FIXME: has client gone away? */
      return 1;
    }

  /* Not connected.  Connect with a client if there is one.  */

  FD_ZERO (&readfds);
  FD_SET (sockser_listen_fd, &readfds);

  /* ??? One can certainly argue this should be done differently,
     but for now this is sufficient.  */
  tv.tv_sec = 0;
  tv.tv_usec = sockser_timeout;

  numfds = select (sockser_listen_fd + 1, &readfds, 0, 0, &tv);
  if (numfds <= 0)
    return 0;

  addrlen = sizeof (sockaddr);
  sockser_fd = accept (sockser_listen_fd, &sockaddr, &addrlen);
  if (sockser_fd < 0)
    return 0;

  /* Set non-blocking i/o.  */
  flags = fcntl (sockser_fd, F_GETFL);
  flags |= O_NONBLOCK | O_NDELAY;
  if (fcntl (sockser_fd, F_SETFL, flags) == -1)
    {
      sim_io_eprintf (sd, "unable to set nonblocking i/o");
      close (sockser_fd);
      sockser_fd = -1;
      return 0;
    }
  return 1;
}

int
dv_sockser_status (SIM_DESC sd)
{
  int numrfds,numwfds,status;
  struct timeval tv;
  fd_set readfds,writefds;

  /* status to return if the socket isn't set up, or select fails */
  status = DV_SOCKSER_INPUT_EMPTY | DV_SOCKSER_OUTPUT_EMPTY;

  if (! connected_p (sd))
    return status;

  FD_ZERO (&readfds);
  FD_ZERO (&writefds);
  FD_SET (sockser_fd, &readfds);
  FD_SET (sockser_fd, &writefds);

  /* ??? One can certainly argue this should be done differently,
     but for now this is sufficient.  The read is done separately
     from the write to enforce the delay which we heuristically set to
     once every SOCKSER_TIMEOUT_FREQ tries.
     No, this isn't great for SMP situations, blah blah blah.  */

  {
    static int n;
#define SOCKSER_TIMEOUT_FREQ 42
    if (++n == SOCKSER_TIMEOUT_FREQ)
      n = 0;
    if (n == 0)
      {
	tv.tv_sec = 0;
	tv.tv_usec = sockser_timeout;
	numrfds = select (sockser_fd + 1, &readfds, 0, 0, &tv);
	tv.tv_sec = 0;
	tv.tv_usec = 0;
	numwfds = select (sockser_fd + 1, 0, &writefds, 0, &tv);
      }
    else /* do both selects at once */
      {
	tv.tv_sec = 0;
	tv.tv_usec = 0;
	numrfds = numwfds = select (sockser_fd + 1, &readfds, &writefds, 0, &tv);
      }
  }

  status = 0;
  if (numrfds <= 0 || ! FD_ISSET (sockser_fd, &readfds))
    status |= DV_SOCKSER_INPUT_EMPTY;
  if (numwfds <= 0 || FD_ISSET (sockser_fd, &writefds))
    status |= DV_SOCKSER_OUTPUT_EMPTY;
  return status;
}

int
dv_sockser_write (SIM_DESC sd, unsigned char c)
{
  int n;

  if (! connected_p (sd))
    return -1;
  n = write (sockser_fd, &c, 1);
  if (n == -1)
    {
      if (errno == EPIPE)
	{
	  close (sockser_fd);
	  sockser_fd = -1;
	}
      return -1;
    }
  if (n != 1)
    return -1;
  return 1;
}

int
dv_sockser_read (SIM_DESC sd)
{
  unsigned char c;
  int n;

  if (! connected_p (sd))
    return -1;
  n = read (sockser_fd, &c, 1);
  /* ??? We're assuming semantics that may not be correct for all hosts.
     In particular (from cvssrc/src/server.c), this assumes that we are using
     BSD or POSIX nonblocking I/O.  System V nonblocking I/O returns zero if
     there is nothing to read.  */
  if (n == 0)
    {
      close (sockser_fd);
      sockser_fd = -1;
      return -1;
    }
  if (n != 1)
    return -1;
  return c;
}