aboutsummaryrefslogtreecommitdiff
path: root/gdb/gdbserver/low-linux.c
blob: a260575222ad2c7e190439578ba9b9848fe794e7 (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
/* Low level interface to ptrace, for the remote server for GDB.
   Copyright (C) 1995, 1996 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 <sys/wait.h>
#include "frame.h"
#include "inferior.h"

#include <stdio.h>
#include <sys/param.h>
#include <sys/dir.h>
#include <sys/user.h>
#include <signal.h>
#include <sys/ioctl.h>
#if 0
#include <sgtty.h>
#endif
#include <fcntl.h>

/***************Begin MY defs*********************/
int quit_flag = 0;
char registers[REGISTER_BYTES];

/* Index within `registers' of the first byte of the space for
   register N.  */


char buf2[MAX_REGISTER_RAW_SIZE];
/***************End MY defs*********************/

#include <sys/ptrace.h>
#if 0
#include <machine/reg.h>
#endif

extern char **environ;
extern int errno;
extern int inferior_pid;
void quit (), perror_with_name ();
int query ();

/* Start an inferior process and returns its pid.
   ALLARGS is a vector of program-name and args.
   ENV is the environment vector to pass.  */

int
create_inferior (program, allargs)
     char *program;
     char **allargs;
{
  int pid;

  pid = fork ();
  if (pid < 0)
    perror_with_name ("fork");

  if (pid == 0)
    {
      ptrace (PTRACE_TRACEME, 0, 0, 0);

      execv (program, allargs);

      fprintf (stderr, "Cannot exec %s: %s.\n", program,
	       errno < sys_nerr ? sys_errlist[errno] : "unknown error");
      fflush (stderr);
      _exit (0177);
    }

  return pid;
}

/* Kill the inferior process.  Make us have no inferior.  */

void
kill_inferior ()
{
  if (inferior_pid == 0)
    return;
  ptrace (PTRACE_KILL, inferior_pid, 0, 0);
  wait (0);
  /*************inferior_died ();****VK**************/
}

/* Return nonzero if the given thread is still alive.  */
int
mythread_alive (pid)
     int pid;
{
  return 1;
}

/* Wait for process, returns status */

unsigned char
mywait (status)
     char *status;
{
  int pid;
  union wait w;

  pid = wait (&w);
  if (pid != inferior_pid)
    perror_with_name ("wait");

  if (WIFEXITED (w))
    {
      fprintf (stderr, "\nChild exited with retcode = %x \n", WEXITSTATUS (w));
      *status = 'W';
      return ((unsigned char) WEXITSTATUS (w));
    }
  else if (!WIFSTOPPED (w))
    {
      fprintf (stderr, "\nChild terminated with signal = %x \n", WTERMSIG (w));
      *status = 'X';
      return ((unsigned char) WTERMSIG (w));
    }

  fetch_inferior_registers (0);

  *status = 'T';
  return ((unsigned char) WSTOPSIG (w));
}

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

void
myresume (step, signal)
     int step;
     int signal;
{
  errno = 0;
  ptrace (step ? PTRACE_SINGLESTEP : PTRACE_CONT, inferior_pid, 1, signal);
  if (errno)
    perror_with_name ("ptrace");
}


#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

/* this table must line up with REGISTER_NAMES in tm-i386v.h */
/* symbols like 'EAX' come from <sys/reg.h> */
static int regmap[] = 
{
  EAX, ECX, EDX, EBX,
  UESP, EBP, ESI, EDI,
  EIP, EFL, CS, SS,
  DS, ES, FS, GS,
};

int
i386_register_u_addr (blockend, regnum)
     int blockend;
     int regnum;
{
#if 0
  /* this will be needed if fp registers are reinstated */
  /* for now, you can look at them with 'info float'
   * sys5 wont let you change them with ptrace anyway
   */
  if (regnum >= FP0_REGNUM && regnum <= FP7_REGNUM) 
    {
      int ubase, fpstate;
      struct user u;
      ubase = blockend + 4 * (SS + 1) - KSTKSZ;
      fpstate = ubase + ((char *)&u.u_fpstate - (char *)&u);
      return (fpstate + 0x1c + 10 * (regnum - FP0_REGNUM));
    } 
  else
#endif
    return (blockend + 4 * regmap[regnum]);
  
}

CORE_ADDR
register_addr (regno, blockend)
     int regno;
     CORE_ADDR blockend;
{
  CORE_ADDR addr;

  if (regno < 0 || regno >= ARCH_NUM_REGS)
    error ("Invalid register number %d.", regno);

  REGISTER_U_ADDR (addr, blockend, regno);

  return addr;
}

/* Fetch one register.  */

static void
fetch_register (regno)
     int regno;
{
  register unsigned int regaddr;
  register int i;

  /* Offset of registers within the u area.  */
  unsigned int offset;

  offset = U_REGS_OFFSET;

  regaddr = register_addr (regno, offset);
  for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (int))
    {
      errno = 0;
      *(int *) &registers[ regno * 4 + i] = ptrace (PTRACE_PEEKUSR, inferior_pid,
				 (PTRACE_ARG3_TYPE) regaddr, 0);
      regaddr += sizeof (int);
      if (errno != 0)
	{
	  /* Warning, not error, in case we are attached; sometimes the
	     kernel doesn't let us at the registers.  */
	  char *err = strerror (errno);
	  char *msg = alloca (strlen (err) + 128);
	  sprintf (msg, "reading register %d: %s", regno, err);
	  error (msg);
	  goto error_exit;
	}
    }
 error_exit:;
}

/* Fetch all registers, or just one, from the child process.  */

void
fetch_inferior_registers (regno)
     int regno;
{
  if (regno == -1 || regno == 0)
    for (regno = 0; regno < NUM_REGS-NUM_FREGS; regno++)
      fetch_register (regno);
  else
    fetch_register (regno);
}

/* Store our register values back into the inferior.
   If REGNO is -1, do this for all registers.
   Otherwise, REGNO specifies which register (so we can save time).  */

void
store_inferior_registers (regno)
     int regno;
{
  register unsigned int regaddr;
  register int i;
  unsigned int offset = U_REGS_OFFSET;

  if (regno >= 0)
    {
#if 0
      if (CANNOT_STORE_REGISTER (regno))
	return;
#endif
      regaddr = register_addr (regno, offset);
      errno = 0;
#if 0
      if (regno == PCOQ_HEAD_REGNUM || regno == PCOQ_TAIL_REGNUM)
        {
          scratch = *(int *) &registers[REGISTER_BYTE (regno)] | 0x3;
          ptrace (PT_WUREGS, inferior_pid, (PTRACE_ARG3_TYPE) regaddr,
                  scratch, 0);
          if (errno != 0)
            {
	      /* Error, even if attached.  Failing to write these two
		 registers is pretty serious.  */
              sprintf (buf, "writing register number %d", regno);
              perror_with_name (buf);
            }
        }
      else
#endif
	for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof(int))
	  {
	    errno = 0;
	    ptrace (PTRACE_POKEUSR, inferior_pid, (PTRACE_ARG3_TYPE) regaddr,
		    *(int *) &registers[REGISTER_BYTE (regno) + i]);
	    if (errno != 0)
	      {
		/* Warning, not error, in case we are attached; sometimes the
		   kernel doesn't let us at the registers.  */
		char *err = strerror (errno);
		char *msg = alloca (strlen (err) + 128);
		sprintf (msg, "writing register %d: %s",
			 regno, err);
		error (msg);
		return;
	      }
	    regaddr += sizeof(int);
	  }
    }
  else
    for (regno = 0; regno < NUM_REGS-NUM_FREGS; regno++)
      store_inferior_registers (regno);
}

/* 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 from inferior's memory starting at MEMADDR
   to debugger memory starting at MYADDR.  */

void
read_inferior_memory (memaddr, myaddr, len)
     CORE_ADDR memaddr;
     char *myaddr;
     int len;
{
  register int i;
  /* Round starting address down to longword boundary.  */
  register CORE_ADDR addr = memaddr & -sizeof (int);
  /* Round ending address up; get number of longwords that makes.  */
  register int count
  = (((memaddr + len) - addr) + sizeof (int) - 1) / sizeof (int);
  /* Allocate buffer of that many longwords.  */
  register int *buffer = (int *) alloca (count * sizeof (int));

  /* Read all the longwords */
  for (i = 0; i < count; i++, addr += sizeof (int))
    {
      buffer[i] = ptrace (PTRACE_PEEKTEXT, inferior_pid, addr, 0);
    }

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

/* Copy LEN bytes of data from debugger memory at MYADDR
   to inferior's memory at MEMADDR.
   On failure (cannot write the inferior)
   returns the value of errno.  */

int
write_inferior_memory (memaddr, myaddr, len)
     CORE_ADDR memaddr;
     char *myaddr;
     int len;
{
  register int i;
  /* Round starting address down to longword boundary.  */
  register CORE_ADDR addr = memaddr & -sizeof (int);
  /* Round ending address up; get number of longwords that makes.  */
  register int count
  = (((memaddr + len) - addr) + sizeof (int) - 1) / sizeof (int);
  /* Allocate buffer of that many longwords.  */
  register int *buffer = (int *) alloca (count * sizeof (int));
  extern int errno;

  /* Fill start and end extra bytes of buffer with existing memory data.  */

  buffer[0] = ptrace (PTRACE_PEEKTEXT, inferior_pid, addr, 0);

  if (count > 1)
    {
      buffer[count - 1]
	= ptrace (PTRACE_PEEKTEXT, inferior_pid,
		  addr + (count - 1) * sizeof (int), 0);
    }

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

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

  /* Write the entire buffer.  */

  for (i = 0; i < count; i++, addr += sizeof (int))
    {
      errno = 0;
      ptrace (PTRACE_POKETEXT, inferior_pid, addr, buffer[i]);
      if (errno)
	return errno;
    }

  return 0;
}

void
initialize ()
{
  inferior_pid = 0;
}

int
have_inferior_p ()
{
  return inferior_pid != 0;
}