/* Low level interface to ptrace, for the remote server for GDB.
   Copyright (C) 1995 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 <dirent.h>
#include <sys/user.h>
#include <signal.h>
#include <sys/ioctl.h>
#include <sgtty.h>
#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>
#include <machine/reg.h>

extern char **environ;
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 (PT_TRACE_ME, 0, 0, 0);

      execv (program, allargs);

      fprintf (stderr, "Cannot exec %s: %s.\n", program, strerror(errno));
      fflush (stderr);
      _exit (0177);
    }

  return pid;
}

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

void
kill_inferior ()
{
  if (inferior_pid == 0)
    return;
  ptrace (PT_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;
  int 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 ? PT_STEP : PT_CONTINUE, inferior_pid,
	  (PTRACE_ARG3_TYPE) 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

unsigned int
register_addr (regno, blockend)
     int regno;
     int blockend;
{
  int 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;
  char buf[MAX_REGISTER_RAW_SIZE];
  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 * sizeof(int) + i] = 
	  ptrace (PT_READ_U, 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; 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;
  char buf[80];
  extern char registers[];
  register int i;
  unsigned int offset = U_REGS_OFFSET;
  int scratch;

  if (regno >= 0)
    {
      regaddr = register_addr (regno, offset);
      errno = 0;
      for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof(int))
	{
	  errno = 0;
	  ptrace (PT_WRITE_U, 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; 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.  */

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 (PT_READ_I, inferior_pid, (PTRACE_ARG3_TYPE) 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 (PT_READ_I, inferior_pid,
		      (PTRACE_ARG3_TYPE) addr, 0);

  if (count > 1)
    {
      buffer[count - 1]
	= ptrace (PT_READ_I, inferior_pid,
	      	  (PTRACE_ARG3_TYPE) 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 (PT_WRITE_I, inferior_pid, (PTRACE_ARG3_TYPE) addr, buffer[i]);
      if (errno)
	return errno;
    }

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

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

/* Some systems don't provide all the registers on a trap.  Use SS as a
   default if so.  */

#ifndef tDS
#define tDS tSS
#endif
#ifndef tES
#define tES tSS
#endif
#ifndef tFS
#define tFS tSS
#endif
#ifndef tGS
#define tGS tSS
#endif

/* These tables map between the registers on a trap frame, and the register
   order used by the rest of GDB.  */
/* this table must line up with REGISTER_NAMES in tm-i386.h */
/* symbols like 'tEAX' come from <machine/reg.h> */
static int tregmap[] = 
{
  tEAX, tECX, tEDX, tEBX,
  tESP, tEBP, tESI, tEDI,
  tEIP, tEFLAGS, tCS, tSS,
  tDS, tES, tFS, tGS
};

#ifdef sEAX
static int sregmap[] = 
{
  sEAX, sECX, sEDX, sEBX,
  sESP, sEBP, sESI, sEDI,
  sEIP, sEFLAGS, sCS, sSS
};
#else /* No sEAX */

/* FreeBSD has decided to collapse the s* and t* symbols.  So if the s*
   ones aren't around, use the t* ones for sregmap too.  */

static int sregmap[] = 
{
  tEAX, tECX, tEDX, tEBX,
  tESP, tEBP, tESI, tEDI,
  tEIP, tEFLAGS, tCS, tSS,
  tDS, tES, tFS, tGS
};
#endif /* No sEAX */

/* blockend is the value of u.u_ar0, and points to the
   place where ES is stored.  */

int
i386_register_u_addr (blockend, regnum)
     int blockend;
     int regnum;
{
  /* The following condition is a kludge to get at the proper register map
     depending upon the state of pcb_flag.
     The proper condition would be
     if (u.u_pcb.pcb_flag & FM_TRAP)
     but that would require a ptrace call here and wouldn't work
     for corefiles.  */

  if (blockend < 0x1fcc)
    return (blockend + 4 * tregmap[regnum]);
  else
    return (blockend + 4 * sregmap[regnum]);
}