aboutsummaryrefslogtreecommitdiff
path: root/gdb/ser-pipe.c
blob: 0c36a31e07ae27c41d9fa45c6c8fb54d41c3d9dd (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
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
/* Serial interface for a pipe to a separate program
   Copyright 1999 Free Software Foundation, Inc.

   Contributed by Cygnus Solutions.

   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 <sys/types.h>
#ifdef HAVE_SYS_WAIT_H
#include <sys/wait.h>
#endif
#include <sys/socket.h>
#include <sys/time.h>
#include <fcntl.h>

#include "signals.h"
#include "gdb_string.h"

extern int (*ui_loop_hook) PARAMS ((int));

static int pipe_open PARAMS ((serial_t scb, const char *name));
static void pipe_raw PARAMS ((serial_t scb));
static int wait_for PARAMS ((serial_t scb, int timeout));
static int pipe_readchar PARAMS ((serial_t scb, int timeout));
static int pipe_setbaudrate PARAMS ((serial_t scb, int rate));
static int pipe_setstopbits PARAMS ((serial_t scb, int num));
static int pipe_write PARAMS ((serial_t scb, const char *str, int len));
/* FIXME: static void pipe_restore PARAMS ((serial_t scb)); */
static void pipe_close PARAMS ((serial_t scb));
static serial_ttystate pipe_get_tty_state PARAMS ((serial_t scb));
static int pipe_set_tty_state PARAMS ((serial_t scb, serial_ttystate state));
static int pipe_return_0 PARAMS ((serial_t));
static int pipe_noflush_set_tty_state PARAMS ((serial_t, serial_ttystate,
					       serial_ttystate));
static void pipe_print_tty_state PARAMS ((serial_t, serial_ttystate));

extern void _initialize_ser_pipe PARAMS ((void));

#undef XMALLOC
#define XMALLOC(T) ((T*) xmalloc (sizeof (T)))


struct pipe_state
  {
    int pid;
  };

/* Open up a raw pipe */

static int
pipe_open (scb, name)
     serial_t scb;
     const char *name;
{
#if !defined(O_NONBLOCK) || !defined(F_GETFL) || !defined(F_SETFL) || !HAVE_SOCKETPAIR
  return -1;
#else
  struct pipe_state *state;
  /* This chunk: */
  /* Copyright (c) 1988, 1993
   *      The Regents of the University of California.  All rights reserved.
   *
   * This code is derived from software written by Ken Arnold and
   * published in UNIX Review, Vol. 6, No. 8.
   */
  int pdes[2];
  int pid;
  if (socketpair (AF_UNIX, SOCK_STREAM, 0, pdes) < 0)
    return -1;

  pid = vfork ();
  
  /* Error. */
  if (pid == -1)
    {
      close (pdes[0]);
      close (pdes[1]);
      return -1;
    }

  /* Child. */
  if (pid == 0)
    {
      /* re-wire pdes[1] to stdin/stdout */
      close (pdes[0]);
      if (pdes[1] != STDOUT_FILENO)
	{
	  dup2 (pdes[1], STDOUT_FILENO);
	  close (pdes[1]);
	}
      dup2 (STDOUT_FILENO, STDIN_FILENO);
#if 0
      /* close any stray FD's - FIXME - how? */
      /* POSIX.2 B.3.2.2 "popen() shall ensure that any streams
         from previous popen() calls that remain open in the 
         parent process are closed in the new child process. */
      for (old = pidlist; old; old = old->next)
	close (fileno (old->fp));	/* don't allow a flush */
#endif
      execl ("/bin/sh", "sh", "-c", name + 1, NULL);
      _exit (127);
    }

  /* Parent. */
  close (pdes[1]);
  /* :end chunk */
  state = XMALLOC (struct pipe_state);
  state->pid = pid;
  scb->fd = pdes[0];
  scb->state = state;

  /* Make it non-blocking */
  {
    int flags = fcntl (scb->fd, F_GETFL, 0);
    if (fcntl (scb->fd, F_SETFL, flags | O_NONBLOCK) < 0)
      {
	perror ("ser-pipe");
	pipe_close (scb);
	return -1;
      }
  }

  /* If we don't do this, GDB simply exits when the remote side dies.  */
  signal (SIGPIPE, SIG_IGN);
  return 0;
#endif
}

static serial_ttystate
pipe_get_tty_state (scb)
     serial_t scb;
{
  /* return garbage */
  return xmalloc (sizeof (int));
}

static int
pipe_set_tty_state (scb, ttystate)
     serial_t scb;
     serial_ttystate ttystate;
{
  return 0;
}

static int
pipe_return_0 (scb)
     serial_t scb;
{
  return 0;
}

static void
pipe_raw (scb)
     serial_t scb;
{
  return;			/* Always in raw mode */
}

/* Wait for input on scb, with timeout seconds.  Returns 0 on success,
   otherwise SERIAL_TIMEOUT or SERIAL_ERROR.

   For termio{s}, we actually just setup VTIME if necessary, and let the
   timeout occur in the read() in pipe_read().
 */

static int
wait_for (scb, timeout)
     serial_t scb;
     int timeout;
{
  int numfds;
  struct timeval tv;
  fd_set readfds, exceptfds;

  FD_ZERO (&readfds);
  FD_ZERO (&exceptfds);

  tv.tv_sec = timeout;
  tv.tv_usec = 0;

  FD_SET (scb->fd, &readfds);
  FD_SET (scb->fd, &exceptfds);

  while (1)
    {
      if (timeout >= 0)
	numfds = select (scb->fd + 1, &readfds, 0, &exceptfds, &tv);
      else
	numfds = select (scb->fd + 1, &readfds, 0, &exceptfds, 0);

      if (numfds <= 0)
	{
	  if (numfds == 0)
	    return SERIAL_TIMEOUT;
	  else if (errno == EINTR)
	    continue;
	  else
	    return SERIAL_ERROR;	/* Got an error from select or poll */
	}

      return 0;
    }
}

/* Read a character with user-specified timeout.  TIMEOUT is number of seconds
   to wait, or -1 to wait forever.  Use timeout of 0 to effect a poll.  Returns
   char if successful.  Returns -2 if timeout expired, EOF if line dropped
   dead, or -3 for any other error (see errno in that case). */

static int
pipe_readchar (scb, timeout)
     serial_t scb;
     int timeout;
{
  int status;
  int delta;

  if (scb->bufcnt-- > 0)
    return *scb->bufp++;

  /* We have to be able to keep the GUI alive here, so we break the original
     timeout into steps of 1 second, running the "keep the GUI alive" hook 
     each time through the loop.

     Also, timeout = 0 means to poll, so we just set the delta to 0, so we
     will only go through the loop once. */

  delta = (timeout == 0 ? 0 : 1);
  while (1)
    {

      /* N.B. The UI may destroy our world (for instance by calling
         remote_stop,) in which case we want to get out of here as
         quickly as possible.  It is not safe to touch scb, since
         someone else might have freed it.  The ui_loop_hook signals that 
         we should exit by returning 1. */

      if (ui_loop_hook)
	{
	  if (ui_loop_hook (0))
	    return SERIAL_TIMEOUT;
	}

      status = wait_for (scb, delta);
      timeout -= delta;

      /* If we got a character or an error back from wait_for, then we can 
         break from the loop before the timeout is completed. */

      if (status != SERIAL_TIMEOUT)
	{
	  break;
	}

      /* If we have exhausted the original timeout, then generate
         a SERIAL_TIMEOUT, and pass it out of the loop. */

      else if (timeout == 0)
	{
	  status = SERIAL_TIMEOUT;
	  break;
	}
    }

  if (status < 0)
    return status;

  while (1)
    {
      scb->bufcnt = read (scb->fd, scb->buf, BUFSIZ);
      if (scb->bufcnt != -1 || errno != EINTR)
	break;
    }

  if (scb->bufcnt <= 0)
    {
      if (scb->bufcnt == 0)
	return SERIAL_TIMEOUT;	/* 0 chars means timeout [may need to
				   distinguish between EOF & timeouts
				   someday] */
      else
	return SERIAL_ERROR;	/* Got an error from read */
    }

  scb->bufcnt--;
  scb->bufp = scb->buf;
  return *scb->bufp++;
}

static int
pipe_noflush_set_tty_state (scb, new_ttystate, old_ttystate)
     serial_t scb;
     serial_ttystate new_ttystate;
     serial_ttystate old_ttystate;
{
  return 0;
}

static void
pipe_print_tty_state (scb, ttystate)
     serial_t scb;
     serial_ttystate ttystate;
{
  /* Nothing to print.  */
  return;
}

static int
pipe_setbaudrate (scb, rate)
     serial_t scb;
     int rate;
{
  return 0;			/* Never fails! */
}

static int
pipe_setstopbits (scb, num)
     serial_t scb;
     int num;
{
  return 0;			/* Never fails! */
}

static int
pipe_write (scb, str, len)
     serial_t 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;
}

static void
pipe_close (scb)
     serial_t scb;
{
  struct pipe_state *state = scb->state;
  if (state != NULL)
    {
      int pid = state->pid;
      close (scb->fd);
      scb->fd = -1;
      free (state);
      scb->state = NULL;
      kill (pid, SIGTERM);
      /* Might be useful to check that the child does die. */
    }
}

static struct serial_ops pipe_ops =
{
  "pipe",
  0,
  pipe_open,
  pipe_close,
  pipe_readchar,
  pipe_write,
  pipe_return_0,		/* flush output */
  pipe_return_0,		/* flush input */
  pipe_return_0,		/* send break */
  pipe_raw,
  pipe_get_tty_state,
  pipe_set_tty_state,
  pipe_print_tty_state,
  pipe_noflush_set_tty_state,
  pipe_setbaudrate,
  pipe_setstopbits,
  pipe_return_0,		/* wait for output to drain */
};

void
_initialize_ser_pipe ()
{
  serial_add_interface (&pipe_ops);
}