aboutsummaryrefslogtreecommitdiff
path: root/gdb/infptrace.c
blob: e4637ee28f11a39f4700f93930259fc4854911fa (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
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
/* Low level Unix child interface to ptrace, for GDB when running under Unix.
   Copyright 1988, 89, 90, 91, 92, 93, 94, 95, 96, 1998, 2001 
   Free Software Foundation, Inc.

   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 "frame.h"
#include "inferior.h"
#include "target.h"
#include "gdb_string.h"

#include "gdb_wait.h"

#include "command.h"

#ifdef USG
#include <sys/types.h>
#endif

#include <sys/param.h>
#include "gdb_dirent.h"
#include <signal.h>
#include <sys/ioctl.h>

#ifdef HAVE_PTRACE_H
#include <ptrace.h>
#else
#ifdef HAVE_SYS_PTRACE_H
#include <sys/ptrace.h>
#endif
#endif

#if !defined (PT_READ_I)
#define PT_READ_I	1	/* Read word from text space */
#endif
#if !defined (PT_READ_D)
#define	PT_READ_D	2	/* Read word from data space */
#endif
#if !defined (PT_READ_U)
#define PT_READ_U	3	/* Read word from kernel user struct */
#endif
#if !defined (PT_WRITE_I)
#define PT_WRITE_I	4	/* Write word to text space */
#endif
#if !defined (PT_WRITE_D)
#define PT_WRITE_D	5	/* Write word to data space */
#endif
#if !defined (PT_WRITE_U)
#define PT_WRITE_U	6	/* Write word to kernel user struct */
#endif
#if !defined (PT_CONTINUE)
#define PT_CONTINUE	7	/* Continue after signal */
#endif
#if !defined (PT_STEP)
#define PT_STEP		9	/* Set flag for single stepping */
#endif
#if !defined (PT_KILL)
#define PT_KILL		8	/* Send child a SIGKILL signal */
#endif

#ifndef PT_ATTACH
#define PT_ATTACH PTRACE_ATTACH
#endif
#ifndef PT_DETACH
#define PT_DETACH PTRACE_DETACH
#endif

#include "gdbcore.h"
#ifndef	NO_SYS_FILE
#include <sys/file.h>
#endif
#if 0
/* Don't think this is used anymore.  On the sequent (not sure whether it's
   dynix or ptx or both), it is included unconditionally by sys/user.h and
   not protected against multiple inclusion.  */
#include "gdb_stat.h"
#endif

#if !defined (FETCH_INFERIOR_REGISTERS)
#include <sys/user.h>		/* Probably need to poke the user structure */
#if defined (KERNEL_U_ADDR_BSD)
#include <a.out.h>		/* For struct nlist */
#endif /* KERNEL_U_ADDR_BSD.  */
#endif /* !FETCH_INFERIOR_REGISTERS */

#if !defined (CHILD_XFER_MEMORY)
static void udot_info (char *, int);
#endif

#if !defined (FETCH_INFERIOR_REGISTERS)
static void fetch_register (int);
static void store_register (int);
#endif

/*
 * Some systems (Linux) may have threads implemented as pseudo-processes, 
 * in which case we may be tracing more than one process at a time.
 * In that case, inferior_pid will contain the main process ID and the 
 * individual thread (process) id mashed together.  These macros are 
 * used to separate them out.  The definitions may be overridden in tm.h
 *
 * NOTE: default definitions here are for systems with no threads.
 * Useful definitions MUST be provided in tm.h
 */

#if !defined (PIDGET)	/* Default definition for PIDGET/TIDGET.  */
#define PIDGET(PID)	PID
#define TIDGET(PID)	0
#endif

void _initialize_kernel_u_addr (void);
void _initialize_infptrace (void);


/* This function simply calls ptrace with the given arguments.  
   It exists so that all calls to ptrace are isolated in this 
   machine-dependent file. */
int
call_ptrace (int request, int pid, PTRACE_ARG3_TYPE addr, int data)
{
  int pt_status = 0;

#if 0
  int saved_errno;

  printf ("call_ptrace(request=%d, pid=%d, addr=0x%x, data=0x%x)",
	  request, pid, addr, data);
#endif
#if defined(PT_SETTRC)
  /* If the parent can be told to attach to us, try to do it.  */
  if (request == PT_SETTRC)
    {
      errno = 0;
#if !defined (FIVE_ARG_PTRACE)
      pt_status = ptrace (PT_SETTRC, pid, addr, data);
#else
      /* Deal with HPUX 8.0 braindamage.  We never use the
         calls which require the fifth argument.  */
      pt_status = ptrace (PT_SETTRC, pid, addr, data, 0);
#endif
      if (errno)
	perror_with_name ("ptrace");
#if 0
      printf (" = %d\n", pt_status);
#endif
      if (pt_status < 0)
	return pt_status;
      else
	return parent_attach_all (pid, addr, data);
    }
#endif

#if defined(PT_CONTIN1)
  /* On HPUX, PT_CONTIN1 is a form of continue that preserves pending
     signals.  If it's available, use it.  */
  if (request == PT_CONTINUE)
    request = PT_CONTIN1;
#endif

#if defined(PT_SINGLE1)
  /* On HPUX, PT_SINGLE1 is a form of step that preserves pending
     signals.  If it's available, use it.  */
  if (request == PT_STEP)
    request = PT_SINGLE1;
#endif

#if 0
  saved_errno = errno;
  errno = 0;
#endif
#if !defined (FIVE_ARG_PTRACE)
  pt_status = ptrace (request, pid, addr, data);
#else
  /* Deal with HPUX 8.0 braindamage.  We never use the
     calls which require the fifth argument.  */
  pt_status = ptrace (request, pid, addr, data, 0);
#endif

#if 0
  if (errno)
    printf (" [errno = %d]", errno);

  errno = saved_errno;
  printf (" = 0x%x\n", pt_status);
#endif
  return pt_status;
}


#if defined (DEBUG_PTRACE) || defined (FIVE_ARG_PTRACE)
/* For the rest of the file, use an extra level of indirection */
/* This lets us breakpoint usefully on call_ptrace. */
#define ptrace call_ptrace
#endif

/* Wait for a process to finish, possibly running a target-specific
   hook before returning.  */

int
ptrace_wait (int pid, int *status)
{
  int wstate;

  wstate = wait (status);
  target_post_wait (wstate, *status);
  return wstate;
}

void
kill_inferior (void)
{
  int status;

  if (inferior_pid == 0)
    return;

  /* This once used to call "kill" to kill the inferior just in case
     the inferior was still running.  As others have noted in the past
     (kingdon) there shouldn't be any way to get here if the inferior
     is still running -- else there's a major problem elsewere in gdb
     and it needs to be fixed.

     The kill call causes problems under hpux10, so it's been removed;
     if this causes problems we'll deal with them as they arise.  */
  ptrace (PT_KILL, inferior_pid, (PTRACE_ARG3_TYPE) 0, 0);
  ptrace_wait (0, &status);
  target_mourn_inferior ();
}

#ifndef CHILD_RESUME

/* Resume execution of the inferior process.
   If STEP is nonzero, single-step it.
   If SIGNAL is nonzero, give it that signal.  */

void
child_resume (int pid, int step, enum target_signal signal)
{
  errno = 0;

  if (pid == -1)
    /* Resume all threads.  */
    /* I think this only gets used in the non-threaded case, where "resume
       all threads" and "resume inferior_pid" are the same.  */
    pid = inferior_pid;

  /* An address of (PTRACE_ARG3_TYPE)1 tells ptrace to continue from where
     it was.  (If GDB wanted it to start some other way, we have already
     written a new PC value to the child.)

     If this system does not support PT_STEP, a higher level function will
     have called single_step() to transmute the step request into a
     continue request (by setting breakpoints on all possible successor
     instructions), so we don't have to worry about that here.  */

  if (step)
    {
      if (SOFTWARE_SINGLE_STEP_P)
	internal_error (__FILE__, __LINE__, "failed internal consistency check");		/* Make sure this doesn't happen. */
      else
	ptrace (PT_STEP, pid, (PTRACE_ARG3_TYPE) 1,
		target_signal_to_host (signal));
    }
  else
    ptrace (PT_CONTINUE, pid, (PTRACE_ARG3_TYPE) 1,
	    target_signal_to_host (signal));

  if (errno)
    {
      perror_with_name ("ptrace");
    }
}
#endif /* CHILD_RESUME */


#ifdef ATTACH_DETACH
/* Start debugging the process whose number is PID.  */
int
attach (int pid)
{
  errno = 0;
  ptrace (PT_ATTACH, pid, (PTRACE_ARG3_TYPE) 0, 0);
  if (errno)
    perror_with_name ("ptrace");
  attach_flag = 1;
  return pid;
}

/* Stop debugging the process whose number is PID
   and continue it with signal number SIGNAL.
   SIGNAL = 0 means just continue it.  */

void
detach (int signal)
{
  errno = 0;
  ptrace (PT_DETACH, inferior_pid, (PTRACE_ARG3_TYPE) 1, signal);
  if (errno)
    perror_with_name ("ptrace");
  attach_flag = 0;
}
#endif /* ATTACH_DETACH */

/* Default the type of the ptrace transfer to int.  */
#ifndef PTRACE_XFER_TYPE
#define PTRACE_XFER_TYPE int
#endif

/* KERNEL_U_ADDR is the amount to subtract from u.u_ar0
   to get the offset in the core file of the register values.  */
#if defined (KERNEL_U_ADDR_BSD) && !defined (FETCH_INFERIOR_REGISTERS)
/* Get kernel_u_addr using BSD-style nlist().  */
CORE_ADDR kernel_u_addr;
#endif /* KERNEL_U_ADDR_BSD.  */

void
_initialize_kernel_u_addr (void)
{
#if defined (KERNEL_U_ADDR_BSD) && !defined (FETCH_INFERIOR_REGISTERS)
  struct nlist names[2];

  names[0].n_un.n_name = "_u";
  names[1].n_un.n_name = NULL;
  if (nlist ("/vmunix", names) == 0)
    kernel_u_addr = names[0].n_value;
  else
    internal_error (__FILE__, __LINE__,
		    "Unable to get kernel u area address.");
#endif /* KERNEL_U_ADDR_BSD.  */
}

#if !defined (FETCH_INFERIOR_REGISTERS)

#if !defined (offsetof)
#define offsetof(TYPE, MEMBER) ((unsigned long) &((TYPE *)0)->MEMBER)
#endif

/* U_REGS_OFFSET is the offset of the registers within the u area.  */
#if !defined (U_REGS_OFFSET)
#define U_REGS_OFFSET \
  ptrace (PT_READ_U, inferior_pid, \
	  (PTRACE_ARG3_TYPE) (offsetof (struct user, u_ar0)), 0) \
    - KERNEL_U_ADDR
#endif

/* Registers we shouldn't try to fetch.  */
#if !defined (CANNOT_FETCH_REGISTER)
#define CANNOT_FETCH_REGISTER(regno) 0
#endif

/* Fetch one register.  */

static void
fetch_register (int regno)
{
  /* This isn't really an address.  But ptrace thinks of it as one.  */
  CORE_ADDR regaddr;
  char mess[128];		/* For messages */
  register int i;
  unsigned int offset;		/* Offset of registers within the u area.  */
  char buf[MAX_REGISTER_RAW_SIZE];
  int tid;

  if (CANNOT_FETCH_REGISTER (regno))
    {
      memset (buf, '\0', REGISTER_RAW_SIZE (regno));	/* Supply zeroes */
      supply_register (regno, buf);
      return;
    }

  /* Overload thread id onto process id */
  if ((tid = TIDGET (inferior_pid)) == 0)
    tid = inferior_pid;		/* no thread id, just use process id */

  offset = U_REGS_OFFSET;

  regaddr = register_addr (regno, offset);
  for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (PTRACE_XFER_TYPE))
    {
      errno = 0;
      *(PTRACE_XFER_TYPE *) & buf[i] = ptrace (PT_READ_U, tid,
					       (PTRACE_ARG3_TYPE) regaddr, 0);
      regaddr += sizeof (PTRACE_XFER_TYPE);
      if (errno != 0)
	{
	  sprintf (mess, "reading register %s (#%d)", 
		   REGISTER_NAME (regno), regno);
	  perror_with_name (mess);
	}
    }
  supply_register (regno, buf);
}


/* Fetch register values from the inferior.
   If REGNO is negative, do this for all registers.
   Otherwise, REGNO specifies which register (so we can save time). */

void
fetch_inferior_registers (int regno)
{
  if (regno >= 0)
    {
      fetch_register (regno);
    }
  else
    {
      for (regno = 0; regno < ARCH_NUM_REGS; regno++)
	{
	  fetch_register (regno);
	}
    }
}

/* Registers we shouldn't try to store.  */
#if !defined (CANNOT_STORE_REGISTER)
#define CANNOT_STORE_REGISTER(regno) 0
#endif

/* Store one register. */

static void
store_register (int regno)
{
  /* This isn't really an address.  But ptrace thinks of it as one.  */
  CORE_ADDR regaddr;
  char mess[128];		/* For messages */
  register int i;
  unsigned int offset;		/* Offset of registers within the u area.  */
  int tid;

  if (CANNOT_STORE_REGISTER (regno))
    {
      return;
    }

  /* Overload thread id onto process id */
  if ((tid = TIDGET (inferior_pid)) == 0)
    tid = inferior_pid;		/* no thread id, just use process id */

  offset = U_REGS_OFFSET;

  regaddr = register_addr (regno, offset);
  for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (PTRACE_XFER_TYPE))
    {
      errno = 0;
      ptrace (PT_WRITE_U, tid, (PTRACE_ARG3_TYPE) regaddr,
	      *(PTRACE_XFER_TYPE *) & registers[REGISTER_BYTE (regno) + i]);
      regaddr += sizeof (PTRACE_XFER_TYPE);
      if (errno != 0)
	{
	  sprintf (mess, "writing register %s (#%d)", 
		   REGISTER_NAME (regno), regno);
	  perror_with_name (mess);
	}
    }
}

/* Store our register values back into the inferior.
   If REGNO is negative, do this for all registers.
   Otherwise, REGNO specifies which register (so we can save time).  */

void
store_inferior_registers (int regno)
{
  if (regno >= 0)
    {
      store_register (regno);
    }
  else
    {
      for (regno = 0; regno < ARCH_NUM_REGS; regno++)
	{
	  store_register (regno);
	}
    }
}
#endif /* !defined (FETCH_INFERIOR_REGISTERS).  */


#if !defined (CHILD_XFER_MEMORY)
/* NOTE! I tried using PTRACE_READDATA, etc., to read and write memory
   in the NEW_SUN_PTRACE case.
   It ought to be straightforward.  But it appears that writing did
   not write the data that I specified.  I cannot understand where
   it got the data that it actually did write.  */

/* Copy LEN bytes to or from inferior's memory starting at MEMADDR
   to debugger memory starting at MYADDR.   Copy to inferior if
   WRITE is nonzero.  TARGET is ignored.

   Returns the length copied, which is either the LEN argument or zero.
   This xfer function does not do partial moves, since child_ops
   doesn't allow memory operations to cross below us in the target stack
   anyway.  */

int
child_xfer_memory (CORE_ADDR memaddr, char *myaddr, int len, int write,
		   struct mem_attrib *attrib ATTRIBUTE_UNUSED,
		   struct target_ops *target)
{
  register int i;
  /* Round starting address down to longword boundary.  */
  register CORE_ADDR addr = memaddr & -sizeof (PTRACE_XFER_TYPE);
  /* Round ending address up; get number of longwords that makes.  */
  register int count
  = (((memaddr + len) - addr) + sizeof (PTRACE_XFER_TYPE) - 1)
  / sizeof (PTRACE_XFER_TYPE);
  /* Allocate buffer of that many longwords.  */
  register PTRACE_XFER_TYPE *buffer
  = (PTRACE_XFER_TYPE *) alloca (count * sizeof (PTRACE_XFER_TYPE));

  if (write)
    {
      /* Fill start and end extra bytes of buffer with existing memory data.  */

      if (addr != memaddr || len < (int) sizeof (PTRACE_XFER_TYPE))
	{
	  /* Need part of initial word -- fetch it.  */
	  buffer[0] = ptrace (PT_READ_I, PIDGET (inferior_pid), 
			      (PTRACE_ARG3_TYPE) addr, 0);
	}

      if (count > 1)		/* FIXME, avoid if even boundary */
	{
	  buffer[count - 1] 
	    = ptrace (PT_READ_I, PIDGET (inferior_pid),
		      ((PTRACE_ARG3_TYPE)
		       (addr + (count - 1) * sizeof (PTRACE_XFER_TYPE))),
		      0);
	}

      /* Copy data to be written over corresponding part of buffer */

      memcpy ((char *) buffer + (memaddr & (sizeof (PTRACE_XFER_TYPE) - 1)),
	      myaddr,
	      len);

      /* Write the entire buffer.  */

      for (i = 0; i < count; i++, addr += sizeof (PTRACE_XFER_TYPE))
	{
	  errno = 0;
	  ptrace (PT_WRITE_D, PIDGET (inferior_pid), 
		  (PTRACE_ARG3_TYPE) addr, buffer[i]);
	  if (errno)
	    {
	      /* Using the appropriate one (I or D) is necessary for
	         Gould NP1, at least.  */
	      errno = 0;
	      ptrace (PT_WRITE_I, PIDGET (inferior_pid), 
		      (PTRACE_ARG3_TYPE) addr, buffer[i]);
	    }
	  if (errno)
	    return 0;
	}
#ifdef CLEAR_INSN_CACHE
      CLEAR_INSN_CACHE ();
#endif
    }
  else
    {
      /* Read all the longwords */
      for (i = 0; i < count; i++, addr += sizeof (PTRACE_XFER_TYPE))
	{
	  errno = 0;
	  buffer[i] = ptrace (PT_READ_I, PIDGET (inferior_pid),
			      (PTRACE_ARG3_TYPE) addr, 0);
	  if (errno)
	    return 0;
	  QUIT;
	}

      /* Copy appropriate bytes out of the buffer.  */
      memcpy (myaddr,
	      (char *) buffer + (memaddr & (sizeof (PTRACE_XFER_TYPE) - 1)),
	      len);
    }
  return len;
}


static void
udot_info (char *dummy1, int dummy2)
{
#if defined (KERNEL_U_SIZE)
  int udot_off;			/* Offset into user struct */
  int udot_val;			/* Value from user struct at udot_off */
  char mess[128];		/* For messages */
#endif

  if (!target_has_execution)
    {
      error ("The program is not being run.");
    }

#if !defined (KERNEL_U_SIZE)

  /* Adding support for this command is easy.  Typically you just add a
     routine, called "kernel_u_size" that returns the size of the user
     struct, to the appropriate *-nat.c file and then add to the native
     config file "#define KERNEL_U_SIZE kernel_u_size()" */
  error ("Don't know how large ``struct user'' is in this version of gdb.");

#else

  for (udot_off = 0; udot_off < KERNEL_U_SIZE; udot_off += sizeof (udot_val))
    {
      if ((udot_off % 24) == 0)
	{
	  if (udot_off > 0)
	    {
	      printf_filtered ("\n");
	    }
	  printf_filtered ("%04x:", udot_off);
	}
      udot_val = ptrace (PT_READ_U, inferior_pid, (PTRACE_ARG3_TYPE) udot_off, 0);
      if (errno != 0)
	{
	  sprintf (mess, "\nreading user struct at offset 0x%x", udot_off);
	  perror_with_name (mess);
	}
      /* Avoid using nonportable (?) "*" in print specs */
      printf_filtered (sizeof (int) == 4 ? " 0x%08x" : " 0x%16x", udot_val);
    }
  printf_filtered ("\n");

#endif
}
#endif /* !defined (CHILD_XFER_MEMORY).  */


void
_initialize_infptrace (void)
{
#if !defined (CHILD_XFER_MEMORY)
  add_info ("udot", udot_info,
	    "Print contents of kernel ``struct user'' for current child.");
#endif
}