aboutsummaryrefslogtreecommitdiff
path: root/gdbserver/hostio.cc
blob: 8af4fbf4087aa8866c21990529492ea3bbac002a (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
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
/* Host file transfer support for gdbserver.
   Copyright (C) 2007-2020 Free Software Foundation, Inc.

   Contributed by CodeSourcery.

   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 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/>.  */

#include "server.h"
#include "gdb/fileio.h"
#include "hostio.h"

#include <fcntl.h>
#include <limits.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include "gdbsupport/fileio.h"

struct fd_list
{
  int fd;
  struct fd_list *next;
};

static struct fd_list *open_fds;

static int
safe_fromhex (char a, int *nibble)
{
  if (a >= '0' && a <= '9')
    *nibble = a - '0';
  else if (a >= 'a' && a <= 'f')
    *nibble = a - 'a' + 10;
  else if (a >= 'A' && a <= 'F')
    *nibble = a - 'A' + 10;
  else
    return -1;

  return 0;
}

/* Filenames are hex encoded, so the maximum we can handle is half the
   packet buffer size.  Cap to PATH_MAX, if it is shorter.  */
#if !defined (PATH_MAX) || (PATH_MAX > (PBUFSIZ / 2 + 1))
#  define HOSTIO_PATH_MAX (PBUFSIZ / 2 + 1)
#else
#  define HOSTIO_PATH_MAX PATH_MAX
#endif

static int
require_filename (char **pp, char *filename)
{
  int count;
  char *p;

  p = *pp;
  count = 0;

  while (*p && *p != ',')
    {
      int nib1, nib2;

      /* Don't allow overflow.  */
      if (count >= HOSTIO_PATH_MAX - 1)
	return -1;

      if (safe_fromhex (p[0], &nib1)
	  || safe_fromhex (p[1], &nib2))
	return -1;

      filename[count++] = nib1 * 16 + nib2;
      p += 2;
    }

  filename[count] = '\0';
  *pp = p;
  return 0;
}

static int
require_int (char **pp, int *value)
{
  char *p;
  int count, firstdigit;

  p = *pp;
  *value = 0;
  count = 0;
  firstdigit = -1;

  while (*p && *p != ',')
    {
      int nib;

      if (safe_fromhex (p[0], &nib))
	return -1;

      if (firstdigit == -1)
	firstdigit = nib;

      /* Don't allow overflow.  */
      if (count >= 8 || (count == 7 && firstdigit >= 0x8))
	return -1;

      *value = *value * 16 + nib;
      p++;
      count++;
    }

  *pp = p;
  return 0;
}

static int
require_data (char *p, int p_len, char **data, int *data_len)
{
  int input_index, output_index, escaped;

  *data = (char *) xmalloc (p_len);

  output_index = 0;
  escaped = 0;
  for (input_index = 0; input_index < p_len; input_index++)
    {
      char b = p[input_index];

      if (escaped)
	{
	  (*data)[output_index++] = b ^ 0x20;
	  escaped = 0;
	}
      else if (b == '}')
	escaped = 1;
      else
	(*data)[output_index++] = b;
    }

  if (escaped)
    {
      free (*data);
      return -1;
    }

  *data_len = output_index;
  return 0;
}

static int
require_comma (char **pp)
{
  if (**pp == ',')
    {
      (*pp)++;
      return 0;
    }
  else
    return -1;
}

static int
require_end (char *p)
{
  if (*p == '\0')
    return 0;
  else
    return -1;
}

static int
require_valid_fd (int fd)
{
  struct fd_list *fd_ptr;

  for (fd_ptr = open_fds; fd_ptr != NULL; fd_ptr = fd_ptr->next)
    if (fd_ptr->fd == fd)
      return 0;

  return -1;
}

/* Fill in own_buf with the last hostio error packet, however it
   suitable for the target.  */
static void
hostio_error (char *own_buf)
{
  the_target->hostio_last_error (own_buf);
}

static void
hostio_packet_error (char *own_buf)
{
  sprintf (own_buf, "F-1,%x", FILEIO_EINVAL);
}

static void
hostio_reply (char *own_buf, int result)
{
  sprintf (own_buf, "F%x", result);
}

static int
hostio_reply_with_data (char *own_buf, char *buffer, int len,
			int *new_packet_len)
{
  int input_index, output_index, out_maxlen;

  sprintf (own_buf, "F%x;", len);
  output_index = strlen (own_buf);

  out_maxlen = PBUFSIZ;

  for (input_index = 0; input_index < len; input_index++)
    {
      char b = buffer[input_index];

      if (b == '$' || b == '#' || b == '}' || b == '*')
	{
	  /* These must be escaped.  */
	  if (output_index + 2 > out_maxlen)
	    break;
	  own_buf[output_index++] = '}';
	  own_buf[output_index++] = b ^ 0x20;
	}
      else
	{
	  if (output_index + 1 > out_maxlen)
	    break;
	  own_buf[output_index++] = b;
	}
    }

  *new_packet_len = output_index;
  return input_index;
}

/* Process ID of inferior whose filesystem hostio functions
   that take FILENAME arguments will use.  Zero means to use
   our own filesystem.  */

static int hostio_fs_pid;

/* See hostio.h.  */

void
hostio_handle_new_gdb_connection (void)
{
  hostio_fs_pid = 0;
}

/* Handle a "vFile:setfs:" packet.  */

static void
handle_setfs (char *own_buf)
{
  char *p;
  int pid;

  /* If the target doesn't have any of the in-filesystem-of methods
     then there's no point in GDB sending "vFile:setfs:" packets.  We
     reply with an empty packet (i.e. we pretend we don't understand
     "vFile:setfs:") and that should stop GDB sending any more.  */
  if (the_target->multifs_open == NULL
      && the_target->multifs_unlink == NULL
      && the_target->multifs_readlink == NULL)
    {
      own_buf[0] = '\0';
      return;
    }

  p = own_buf + strlen ("vFile:setfs:");

  if (require_int (&p, &pid)
      || pid < 0
      || require_end (p))
    {
      hostio_packet_error (own_buf);
      return;
    }

  hostio_fs_pid = pid;

  hostio_reply (own_buf, 0);
}

static void
handle_open (char *own_buf)
{
  char filename[HOSTIO_PATH_MAX];
  char *p;
  int fileio_flags, fileio_mode, flags, fd;
  mode_t mode;
  struct fd_list *new_fd;

  p = own_buf + strlen ("vFile:open:");

  if (require_filename (&p, filename)
      || require_comma (&p)
      || require_int (&p, &fileio_flags)
      || require_comma (&p)
      || require_int (&p, &fileio_mode)
      || require_end (p)
      || fileio_to_host_openflags (fileio_flags, &flags)
      || fileio_to_host_mode (fileio_mode, &mode))
    {
      hostio_packet_error (own_buf);
      return;
    }

  /* We do not need to convert MODE, since the fileio protocol
     uses the standard values.  */
  if (hostio_fs_pid != 0 && the_target->multifs_open != NULL)
    fd = the_target->multifs_open (hostio_fs_pid, filename,
				   flags, mode);
  else
    fd = open (filename, flags, mode);

  if (fd == -1)
    {
      hostio_error (own_buf);
      return;
    }

  /* Record the new file descriptor.  */
  new_fd = XNEW (struct fd_list);
  new_fd->fd = fd;
  new_fd->next = open_fds;
  open_fds = new_fd;

  hostio_reply (own_buf, fd);
}

static void
handle_pread (char *own_buf, int *new_packet_len)
{
  int fd, ret, len, offset, bytes_sent;
  char *p, *data;
  static int max_reply_size = -1;

  p = own_buf + strlen ("vFile:pread:");

  if (require_int (&p, &fd)
      || require_comma (&p)
      || require_valid_fd (fd)
      || require_int (&p, &len)
      || require_comma (&p)
      || require_int (&p, &offset)
      || require_end (p))
    {
      hostio_packet_error (own_buf);
      return;
    }

  /* Do not attempt to read more than the maximum number of bytes
     hostio_reply_with_data can fit in a packet.  We may still read
     too much because of escaping, but this is handled below.  */
  if (max_reply_size == -1)
    {
      sprintf (own_buf, "F%x;", PBUFSIZ);
      max_reply_size = PBUFSIZ - strlen (own_buf);
    }
  if (len > max_reply_size)
    len = max_reply_size;

  data = (char *) xmalloc (len);
#ifdef HAVE_PREAD
  ret = pread (fd, data, len, offset);
#else
  ret = -1;
#endif
  /* If we have no pread or it failed for this file, use lseek/read.  */
  if (ret == -1)
    {
      ret = lseek (fd, offset, SEEK_SET);
      if (ret != -1)
	ret = read (fd, data, len);
    }

  if (ret == -1)
    {
      hostio_error (own_buf);
      free (data);
      return;
    }

  bytes_sent = hostio_reply_with_data (own_buf, data, ret, new_packet_len);

  /* If we were using read, and the data did not all fit in the reply,
     we would have to back up using lseek here.  With pread it does
     not matter.  But we still have a problem; the return value in the
     packet might be wrong, so we must fix it.  This time it will
     definitely fit.  */
  if (bytes_sent < ret)
    bytes_sent = hostio_reply_with_data (own_buf, data, bytes_sent,
					 new_packet_len);

  free (data);
}

static void
handle_pwrite (char *own_buf, int packet_len)
{
  int fd, ret, len, offset;
  char *p, *data;

  p = own_buf + strlen ("vFile:pwrite:");

  if (require_int (&p, &fd)
      || require_comma (&p)
      || require_valid_fd (fd)
      || require_int (&p, &offset)
      || require_comma (&p)
      || require_data (p, packet_len - (p - own_buf), &data, &len))
    {
      hostio_packet_error (own_buf);
      return;
    }

#ifdef HAVE_PWRITE
  ret = pwrite (fd, data, len, offset);
#else
  ret = -1;
#endif
  /* If we have no pwrite or it failed for this file, use lseek/write.  */
  if (ret == -1)
    {
      ret = lseek (fd, offset, SEEK_SET);
      if (ret != -1)
	ret = write (fd, data, len);
    }

  if (ret == -1)
    {
      hostio_error (own_buf);
      free (data);
      return;
    }

  hostio_reply (own_buf, ret);
  free (data);
}

static void
handle_fstat (char *own_buf, int *new_packet_len)
{
  int fd, bytes_sent;
  char *p;
  struct stat st;
  struct fio_stat fst;

  p = own_buf + strlen ("vFile:fstat:");

  if (require_int (&p, &fd)
      || require_valid_fd (fd)
      || require_end (p))
    {
      hostio_packet_error (own_buf);
      return;
    }

  if (fstat (fd, &st) == -1)
    {
      hostio_error (own_buf);
      return;
    }

  host_to_fileio_stat (&st, &fst);

  bytes_sent = hostio_reply_with_data (own_buf,
				       (char *) &fst, sizeof (fst),
				       new_packet_len);

  /* If the response does not fit into a single packet, do not attempt
     to return a partial response, but simply fail.  */
  if (bytes_sent < sizeof (fst))
    write_enn (own_buf);
}

static void
handle_close (char *own_buf)
{
  int fd, ret;
  char *p;
  struct fd_list **open_fd_p, *old_fd;

  p = own_buf + strlen ("vFile:close:");

  if (require_int (&p, &fd)
      || require_valid_fd (fd)
      || require_end (p))
    {
      hostio_packet_error (own_buf);
      return;
    }

  ret = close (fd);

  if (ret == -1)
    {
      hostio_error (own_buf);
      return;
    }

  open_fd_p = &open_fds;
  /* We know that fd is in the list, thanks to require_valid_fd.  */
  while ((*open_fd_p)->fd != fd)
    open_fd_p = &(*open_fd_p)->next;

  old_fd = *open_fd_p;
  *open_fd_p = (*open_fd_p)->next;
  free (old_fd);

  hostio_reply (own_buf, ret);
}

static void
handle_unlink (char *own_buf)
{
  char filename[HOSTIO_PATH_MAX];
  char *p;
  int ret;

  p = own_buf + strlen ("vFile:unlink:");

  if (require_filename (&p, filename)
      || require_end (p))
    {
      hostio_packet_error (own_buf);
      return;
    }

  if (hostio_fs_pid != 0 && the_target->multifs_unlink != NULL)
    ret = the_target->multifs_unlink (hostio_fs_pid, filename);
  else
    ret = unlink (filename);

  if (ret == -1)
    {
      hostio_error (own_buf);
      return;
    }

  hostio_reply (own_buf, ret);
}

static void
handle_readlink (char *own_buf, int *new_packet_len)
{
  char filename[HOSTIO_PATH_MAX], linkname[HOSTIO_PATH_MAX];
  char *p;
  int ret, bytes_sent;

  p = own_buf + strlen ("vFile:readlink:");

  if (require_filename (&p, filename)
      || require_end (p))
    {
      hostio_packet_error (own_buf);
      return;
    }

  if (hostio_fs_pid != 0 && the_target->multifs_readlink != NULL)
    ret = the_target->multifs_readlink (hostio_fs_pid, filename,
					linkname,
					sizeof (linkname) - 1);
  else
    ret = readlink (filename, linkname, sizeof (linkname) - 1);

  if (ret == -1)
    {
      hostio_error (own_buf);
      return;
    }

  bytes_sent = hostio_reply_with_data (own_buf, linkname, ret, new_packet_len);

  /* If the response does not fit into a single packet, do not attempt
     to return a partial response, but simply fail.  */
  if (bytes_sent < ret)
    sprintf (own_buf, "F-1,%x", FILEIO_ENAMETOOLONG);
}

/* Handle all the 'F' file transfer packets.  */

int
handle_vFile (char *own_buf, int packet_len, int *new_packet_len)
{
  if (startswith (own_buf, "vFile:open:"))
    handle_open (own_buf);
  else if (startswith (own_buf, "vFile:pread:"))
    handle_pread (own_buf, new_packet_len);
  else if (startswith (own_buf, "vFile:pwrite:"))
    handle_pwrite (own_buf, packet_len);
  else if (startswith (own_buf, "vFile:fstat:"))
    handle_fstat (own_buf, new_packet_len);
  else if (startswith (own_buf, "vFile:close:"))
    handle_close (own_buf);
  else if (startswith (own_buf, "vFile:unlink:"))
    handle_unlink (own_buf);
  else if (startswith (own_buf, "vFile:readlink:"))
    handle_readlink (own_buf, new_packet_len);
  else if (startswith (own_buf, "vFile:setfs:"))
    handle_setfs (own_buf);
  else
    return 0;

  return 1;
}