aboutsummaryrefslogtreecommitdiff
path: root/sysdeps/mach/hurd/ptrace.c
blob: f8ea7375b3eed8a70e3f9d9157264a850a7be971 (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
/* Process tracing interface `ptrace' for GNU Hurd.
   Copyright (C) 1991-2017 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#include <errno.h>
#include <sys/ptrace.h>
#include <sys/types.h>
#include <stdarg.h>
#include <hurd.h>
#include <hurd/signal.h>
#include <hurd/msg.h>
#include <thread_state.h>

/* Perform process tracing functions.  REQUEST is one of the values
   in <sys/ptrace.h>, and determines the action to be taken.
   For all requests except PTRACE_TRACEME, PID specifies the process to be
   traced.

   PID and the other arguments described above for the various requests should
   appear (those that are used for the particular request) as:
     pid_t PID, void *ADDR, int DATA, void *ADDR2
   after PID.  */
int
ptrace (enum __ptrace_request request, ... )
{
  pid_t pid;
  void *addr, *addr2;
  natural_t data;
  va_list ap;

  /* Read data from PID's address space, from ADDR for DATA bytes.  */
  error_t read_data (task_t task, vm_address_t *ourpage, vm_size_t *size)
    {
      /* Read the pages containing the addressed range.  */
      error_t err;
      *size = round_page (addr + data) - trunc_page (addr);
      err = __vm_read (task, trunc_page (addr), *size, ourpage, size);
      return err;
    }

  /* Fetch the thread port for PID's user thread.  */
  error_t fetch_user_thread (task_t task, thread_t *thread)
    {
      thread_t threadbuf[3], *threads = threadbuf;
      mach_msg_type_number_t nthreads = 3, i;
      error_t err = __task_threads (task, &threads, &nthreads);
      if (err)
	return err;
      if (nthreads == 0)
	return EINVAL;
      *thread = threads[0];	/* Assume user thread is first.  */
      for (i = 1; i < nthreads; ++i)
	__mach_port_deallocate (__mach_task_self (), threads[i]);
      if (threads != threadbuf)
	__vm_deallocate (__mach_task_self (),
			 (vm_address_t) threads, nthreads * sizeof threads[0]);
      return 0;
    }

  /* Fetch a thread state structure from PID and store it at ADDR.  */
  int get_regs (int flavor, mach_msg_type_number_t count)
    {
      error_t err;
      task_t task = __pid2task (pid);
      thread_t thread;
      if (task == MACH_PORT_NULL)
	return -1;
      err = fetch_user_thread (task, &thread);
      __mach_port_deallocate (__mach_task_self (), task);
      if (!err)
	err = __thread_get_state (thread, flavor, addr, &count);
      __mach_port_deallocate (__mach_task_self (), thread);
      return err ? __hurd_fail (err) : 0;
    }


  switch (request)
    {
    case PTRACE_TRACEME:
      /* Make this process be traced.  */
      __sigfillset (&_hurdsig_traced);
      __USEPORT (PROC, __proc_mark_traced (port));
      break;

    case PTRACE_CONT:
      va_start (ap, request);
      pid = va_arg (ap, pid_t);
      addr = va_arg (ap, void *);
      data = va_arg (ap, int);
      va_end (ap);
      {
	/* Send a DATA signal to PID, telling it to take the signal
	   normally even if it's traced.  */
	error_t err;
	task_t task = __pid2task (pid);
	if (task == MACH_PORT_NULL)
	  return -1;
	if (data == SIGKILL)
	  err = __task_terminate (task);
	else
	  {
	    if (addr != (void *) 1)
	      {
		/* Move the user thread's PC to ADDR.  */
		thread_t thread;
		err = fetch_user_thread (task, &thread);
		if (!err)
		  {
		    struct machine_thread_state state;
		    mach_msg_type_number_t count = MACHINE_THREAD_STATE_COUNT;
		    err = __thread_get_state (thread,
					      MACHINE_THREAD_STATE_FLAVOR,
					      (natural_t *) &state, &count);
		    if (!err)
		      {
			MACHINE_THREAD_STATE_SET_PC (&state, addr);
			err = __thread_set_state (thread,
						  MACHINE_THREAD_STATE_FLAVOR,
						  (natural_t *) &state, count);
		      }

		  }
		__mach_port_deallocate (__mach_task_self (), thread);
	      }
	    else
	      err = 0;

	    if (! err)
	      /* Tell the process to take the signal (or just resume if 0).  */
	      err = HURD_MSGPORT_RPC
		(__USEPORT (PROC, __proc_getmsgport (port, pid, &msgport)),
		 0, 0, __msg_sig_post_untraced (msgport, data, 0, task));
	  }
	__mach_port_deallocate (__mach_task_self (), task);
	return err ? __hurd_fail (err) : 0;
      }

    case PTRACE_KILL:
      va_start (ap, request);
      pid = va_arg (ap, pid_t);
      va_end (ap);
      /* SIGKILL always just terminates the task,
	 so normal kill is just the same when traced.  */
      return kill (pid, SIGKILL);

    case PTRACE_SINGLESTEP:
      /* This is a machine-dependent kernel RPC on
	 machines that support it.  Punt.  */
      return __hurd_fail (EOPNOTSUPP);

    case PTRACE_ATTACH:
    case PTRACE_DETACH:
      va_start (ap, request);
      pid = va_arg (ap, pid_t);
      va_end (ap);
      {
	/* Tell PID to set or clear its trace bit.  */
	error_t err;
	mach_port_t msgport;
	task_t task = __pid2task (pid);
	if (task == MACH_PORT_NULL)
	  return -1;
	err = __USEPORT (PROC, __proc_getmsgport (port, pid, &msgport));
	if (! err)
	  {
	    err = __msg_set_init_int (msgport, task, INIT_TRACEMASK,
				      request == PTRACE_DETACH ? 0 :
				      ~(sigset_t) 0);
	    if (! err)
	      {
		if (request == PTRACE_ATTACH)
		  /* Now stop the process.  */
		  err = __msg_sig_post (msgport, SIGSTOP, 0, task);
		else
		  /* Resume the process from tracing stop.  */
		  err = __msg_sig_post_untraced (msgport, 0, 0, task);
	      }
	    __mach_port_deallocate (__mach_task_self (), msgport);
	  }
	__mach_port_deallocate (__mach_task_self (), task);
	return err ? __hurd_fail (err) : 0;
      }

    case PTRACE_PEEKTEXT:
    case PTRACE_PEEKDATA:
      va_start (ap, request);
      pid = va_arg (ap, pid_t);
      addr = va_arg (ap, void *);
      va_end (ap);
      {
	/* Read the page (or two pages, if the word lies on a boundary)
	   containing the addressed word.  */
	error_t err;
	vm_address_t ourpage;
	vm_size_t size;
	natural_t word;
	task_t task = __pid2task (pid);
	if (task == MACH_PORT_NULL)
	  return -1;
	data = sizeof word;
	ourpage = 0;
	size = 0;
	err = read_data (task, &ourpage, &size);
	__mach_port_deallocate (__mach_task_self (), task);
	if (err)
	  return __hurd_fail (err);
	word = *(natural_t *) ((vm_address_t) addr - trunc_page (addr)
			       + ourpage);
	__vm_deallocate (__mach_task_self (), ourpage, size);
	return word;
      }

    case PTRACE_PEEKUSER:
    case PTRACE_POKEUSER:
      /* U area, what's that?  */
      return __hurd_fail (EOPNOTSUPP);

    case PTRACE_GETREGS:
    case PTRACE_SETREGS:
      va_start (ap, request);
      pid = va_arg (ap, pid_t);
      addr = va_arg (ap, void *);
      va_end (ap);
      return get_regs (MACHINE_THREAD_STATE_FLAVOR,
		       MACHINE_THREAD_STATE_COUNT);

    case PTRACE_GETFPREGS:
    case PTRACE_SETFPREGS:
      va_start (ap, request);
      pid = va_arg (ap, pid_t);
      addr = va_arg (ap, void *);
      va_end (ap);
#ifdef MACHINE_THREAD_FLOAT_STATE_FLAVOR
      return get_regs (MACHINE_THREAD_FLOAT_STATE_FLAVOR,
		       MACHINE_THREAD_FLOAT_STATE_COUNT);
#else
      return __hurd_fail (EOPNOTSUPP);
#endif

    case PTRACE_GETFPAREGS:
    case PTRACE_SETFPAREGS:
      va_start (ap, request);
      pid = va_arg (ap, pid_t);
      addr = va_arg (ap, void *);
      va_end (ap);
#ifdef MACHINE_THREAD_FPA_STATE_FLAVOR
      return get_regs (MACHINE_THREAD_FPA_STATE_FLAVOR,
		       MACHINE_THREAD_FPA_STATE_COUNT);
#else
      return __hurd_fail (EOPNOTSUPP);
#endif

    case PTRACE_POKETEXT:
    case PTRACE_POKEDATA:
      va_start (ap, request);
      pid = va_arg (ap, pid_t);
      addr = va_arg (ap, void *);
      data = va_arg (ap, int);
      va_end (ap);
      {
	/* Read the page (or two pages, if the word lies on a boundary)
	   containing the addressed word.  */
	error_t err;
	vm_address_t ourpage;
	vm_size_t size;
	task_t task = __pid2task (pid);
	if (task == MACH_PORT_NULL)
	  return -1;
	data = sizeof (natural_t);
	ourpage = 0;
	size = 0;
	err = read_data (task, &ourpage, &size);

	if (!err)
	  {
	    /* Now modify the specified word and write the page back.  */
	    *(natural_t *) ((vm_address_t) addr - trunc_page (addr)
			    + ourpage) = data;
	    err = __vm_write (task, trunc_page (addr), ourpage, size);
	    __vm_deallocate (__mach_task_self (), ourpage, size);
	  }

	__mach_port_deallocate (__mach_task_self (), task);
	return err ? __hurd_fail (err) : 0;
      }

    case PTRACE_READDATA:
    case PTRACE_READTEXT:
      va_start (ap, request);
      pid = va_arg (ap, pid_t);
      addr = va_arg (ap, void *);
      data = va_arg (ap, int);
      addr2 = va_arg (ap, void *);
      va_end (ap);
      {
	error_t err;
	vm_address_t ourpage;
	vm_size_t size;
	task_t task = __pid2task (pid);
	if (task == MACH_PORT_NULL)
	  return -1;
	if (((vm_address_t) addr2 + data) % __vm_page_size == 0)
	  {
	    /* Perhaps we can write directly to the user's buffer.  */
	    ourpage = (vm_address_t) addr2;
	    size = data;
	  }
	else
	  {
	    ourpage = 0;
	    size = 0;
	  }
	err = read_data (task, &ourpage, &size);
	__mach_port_deallocate (__mach_task_self (), task);
	if (!err && ourpage != (vm_address_t) addr2)
	  {
	    memcpy (addr2, (void *) ourpage, data);
	    __vm_deallocate (__mach_task_self (), ourpage, size);
	  }
	return err ? __hurd_fail (err) : 0;
      }

    case PTRACE_WRITEDATA:
    case PTRACE_WRITETEXT:
      va_start (ap, request);
      pid = va_arg (ap, pid_t);
      addr = va_arg (ap, void *);
      data = va_arg (ap, int);
      addr2 = va_arg (ap, void *);
      va_end (ap);
      {
	error_t err;
	vm_address_t ourpage;
	vm_size_t size;
	task_t task = __pid2task (pid);
	if (task == MACH_PORT_NULL)
	  return -1;
	if ((vm_address_t) addr % __vm_page_size == 0 &&
	    (vm_address_t) data % __vm_page_size == 0)
	  {
	    /* Writing whole pages; can go directly from the user's buffer.  */
	    ourpage = (vm_address_t) addr2;
	    size = data;
	    err = 0;
	  }
	else
	  {
	    /* Read the task's pages and modify our own copy.  */
	    ourpage = 0;
	    size = 0;
	    err = read_data (task, &ourpage, &size);
	    if (!err)
	      memcpy ((void *) ((vm_address_t) addr - trunc_page (addr)
				+ ourpage),
		      addr2,
		      data);
	  }
	if (!err)
	  /* Write back the modified pages.  */
	  err = __vm_write (task, trunc_page (addr), ourpage, size);
	__mach_port_deallocate (__mach_task_self (), task);
	return err ? __hurd_fail (err) : 0;
      }

    default:
      errno = EINVAL;
      return -1;
    }

  return 0;
}