procfs.c

早期freebsd实现

      unconditionally_kill_inferior ();
      target_mourn_inferior ();
    }
}

/*

LOCAL FUNCTION

	unconditionally_kill_inferior - terminate the inferior

SYNOPSIS

	static void unconditionally_kill_inferior (void)

DESCRIPTION

	Kill the current inferior.  Should not be called until it
	is at least tested that there is an inferior.

NOTE

	A possibly useful enhancement would be to first try sending
	the inferior a terminate signal, politely asking it to commit
	suicide, before we murder it.

*/

static void
unconditionally_kill_inferior ()
{
  int signo;
  
  signo = SIGKILL;
  ioctl (pi.fd, PIOCKILL, &signo);
  close_proc_file (&pi);
  wait ((int *) 0);
}

/*

LOCAL FUNCTION

	procfs_xfer_memory -- copy data to or from inferior memory space

SYNOPSIS

	int procfs_xfer_memory (CORE_ADDR memaddr, char *myaddr, int len,
		int dowrite, struct target_ops target)

DESCRIPTION

	Copy LEN bytes to/from inferior's memory starting at MEMADDR
	from/to debugger memory starting at MYADDR.  Copy from inferior
	if DOWRITE is zero or to inferior if DOWRITE is nonzero.
  
	Returns the length copied, which is either the LEN argument or
	zero.  This xfer function does not do partial moves, since procfs_ops
	doesn't allow memory operations to cross below us in the target stack
	anyway.

NOTES

	The /proc interface makes this an almost trivial task.
 */

static int
procfs_xfer_memory (memaddr, myaddr, len, dowrite, target)
     CORE_ADDR memaddr;
     char *myaddr;
     int len;
     int dowrite;
     struct target_ops *target; /* ignored */
{
  int nbytes = 0;

  if (lseek (pi.fd, (off_t) memaddr, 0) == (off_t) memaddr)
    {
      if (dowrite)
	{
	  nbytes = write (pi.fd, myaddr, len);
	}
      else
	{
	  nbytes = read (pi.fd, myaddr, len);
	}
      if (nbytes < 0)
	{
	  nbytes = 0;
	}
    }
  return (nbytes);
}

/*

LOCAL FUNCTION

	procfs_store_registers -- copy register values back to inferior

SYNOPSIS

	void procfs_store_registers (int regno)

DESCRIPTION

	Store our current register values back into the inferior.  If
	REGNO is -1 then store all the register, otherwise store just
	the value specified by REGNO.

NOTES

	If we are storing only a single register, we first have to get all
	the current values from the process, overwrite the desired register
	in the gregset with the one we want from gdb's registers, and then
	send the whole set back to the process.  For writing all the
	registers, all we have to do is generate the gregset and send it to
	the process.

	Also note that the process has to be stopped on an event of interest
	for this to work, which basically means that it has to have been
	run under the control of one of the other /proc ioctl calls and not
	ptrace.  Since we don't use ptrace anyway, we don't worry about this
	fine point, but it is worth noting for future reference.

	Gdb is confused about what this function is supposed to return.
	Some versions return a value, others return nothing.  Some are
	declared to return a value and actually return nothing.  Gdb ignores
	anything returned.  (FIXME)

 */

static void
procfs_store_registers (regno)
     int regno;
{
  if (regno != -1)
    {
      ioctl (pi.fd, PIOCGREG, &pi.gregset);
    }
  fill_gregset (&pi.gregset, regno);
  ioctl (pi.fd, PIOCSREG, &pi.gregset);

#if defined (FP0_REGNUM)

  /* Now repeat everything using the floating point register set, if the
     target has floating point hardware. Since we ignore the returned value,
     we'll never know whether it worked or not anyway. */

  if (regno != -1)
    {
      ioctl (pi.fd, PIOCGFPREG, &pi.fpregset);
    }
  fill_fpregset (&pi.fpregset, regno);
  ioctl (pi.fd, PIOCSFPREG, &pi.fpregset);

#endif	/* FP0_REGNUM */

}

/*

LOCAL FUNCTION

	procfs_init_inferior - initialize access to a /proc entry

SYNOPSIS

	void procfs_init_inferior (int pid)

DESCRIPTION

	When gdb starts an inferior, this function is called in the parent
	process immediately after the fork.  It waits for the child to stop
	on the return from the exec system call (the child itself takes care
	of ensuring that this is set up), then sets up the set of signals
	and faults that are to be traced.

NOTES

	If proc_init_failed ever gets called, control returns to the command
	processing loop via the standard error handling code.

 */

static void
procfs_init_inferior (pid)
     int pid;
{

  push_target (&procfs_ops);

  if (!open_proc_file (pid, &pi, O_RDWR))
    {
      proc_init_failed ("can't open process file");
    }
  else
    {
      memset ((char *) &pi.prrun, 0, sizeof (pi.prrun));
      prfillset (&pi.prrun.pr_trace);
      procfs_notice_signals ();
      prfillset (&pi.prrun.pr_fault);
      prdelset (&pi.prrun.pr_fault, FLTPAGE);
      if (ioctl (pi.fd, PIOCWSTOP, &pi.prstatus) < 0)
	{
	  proc_init_failed ("PIOCWSTOP failed");
	}
      else if (ioctl (pi.fd, PIOCSFAULT, &pi.prrun.pr_fault) < 0)
	{
	  proc_init_failed ("PIOCSFAULT failed");
	}
    }
}

/*

GLOBAL FUNCTION

	procfs_notice_signals

SYNOPSIS

	static void procfs_notice_signals (void);

DESCRIPTION

	When the user changes the state of gdb's signal handling via the
	"handle" command, this function gets called to see if any change
	in the /proc interface is required.  It is also called internally
	by other /proc interface functions to initialize the state of
	the traced signal set.

	One thing it does is that signals for which the state is "nostop",
	"noprint", and "pass", have their trace bits reset in the pr_trace
	field, so that they are no longer traced.  This allows them to be
	delivered directly to the inferior without the debugger ever being
	involved.
 */

static void
procfs_notice_signals ()
{
  int signo;

  if (pi.valid)
    {
      for (signo = 0; signo < NSIG; signo++)
	{
	  if (signal_stop_state (signo) == 0 &&
	      signal_print_state (signo) == 0 &&
	      signal_pass_state (signo) == 1)
	    {
	      prdelset (&pi.prrun.pr_trace, signo);
	    }
	  else
	    {
	      praddset (&pi.prrun.pr_trace, signo);
	    }
	}
      if (ioctl (pi.fd, PIOCSTRACE, &pi.prrun.pr_trace))
	{
	  print_sys_errmsg ("PIOCSTRACE failed", errno);
	}
    }
}

/*

LOCAL FUNCTION

	proc_set_exec_trap -- arrange for exec'd child to halt at startup

SYNOPSIS

	void proc_set_exec_trap (void)

DESCRIPTION

	This function is called in the child process when starting up
	an inferior, prior to doing the exec of the actual inferior.
	It sets the child process's exitset to make exit from the exec
	system call an event of interest to stop on, and then simply
	returns.  The child does the exec, the system call returns, and
	the child stops at the first instruction, ready for the gdb
	parent process to take control of it.

NOTE

	We need to use all local variables since the child may be sharing
	it's data space with the parent, if vfork was used rather than
	fork.

	Also note that we want to turn off the inherit-on-fork flag in
	the child process so that any grand-children start with all
	tracing flags cleared.
 */

static void
proc_set_exec_trap ()
{
  sysset_t exitset;
  auto char procname[32];
  int fd;
  
  sprintf (procname, PROC_NAME_FMT, getpid ());
  if ((fd = open (procname, O_RDWR)) < 0)
    {
      perror (procname);
      fflush (stderr);
      _exit (127);
    }
  premptyset (&exitset);

  /* GW: Rationale...
     Not all systems with /proc have all the exec* syscalls with the same
     names.  On the SGI, for example, there is no SYS_exec, but there
     *is* a SYS_execv.  So, we try to account for that. */

#ifdef SYS_exec
  praddset (&exitset, SYS_exec);
#endif
#ifdef SYS_execve
  praddset (&exitset, SYS_execve);
#endif
#ifdef SYS_execv
  praddset(&exitset, SYS_execv);
#endif

  if (ioctl (fd, PIOCSEXIT, &exitset) < 0)
    {
      perror (procname);
      fflush (stderr);
      _exit (127);
    }

  /* Turn off inherit-on-fork flag so that all grand-children of gdb
     start with tracing flags cleared. */

#if defined (PIOCRESET)	/* New method */
  {
      long pr_flags;
      pr_flags = PR_FORK;
      ioctl (fd, PIOCRESET, &pr_flags);
  }
#else
#if defined (PIOCRFORK)	/* Original method */
  ioctl (fd, PIOCRFORK, NULL);
#endif
#endif

  /* Turn on run-on-last-close flag so that this process will not hang
     if GDB goes away for some reason.  */

#if defined (PIOCSET)	/* New method */
  {
      long pr_flags;
      pr_flags = PR_RLC;
      (void) ioctl (fd, PIOCSET, &pr_flags);
  }
#else
#if defined (PIOCSRLC)	/* Original method */
  (void) ioctl (fd, PIOCSRLC, 0);
#endif
#endif
}

/*

GLOBAL FUNCTION

	proc_iterate_over_mappings -- call function for every mapped space

SYNOPSIS

	int proc_iterate_over_mappings (int (*func)())

DESCRIPTION

	Given a pointer to a function, call that function for every
	mapped address space, passing it an open file descriptor for
	the file corresponding to that mapped address space (if any)
	and the base address of the mapped space.  Quit when we hit
	the end of the mappings or the function returns nonzero.
 */

int
proc_iterate_over_mappings (func)
     int (*func) PARAMS ((int, CORE_ADDR));
{
  int nmap;
  int fd;
  int funcstat = 0;
  struct prmap *prmaps;
  struct prmap *prmap;

  if (pi.valid && (ioctl (pi.fd, PIOCNMAP, &nmap) == 0))
    {
      prmaps = (struct prmap *) alloca ((nmap + 1) * sizeof (*prmaps));
      if (ioctl (pi.fd, PIOCMAP, prmaps) == 0)
	{
	  for (prmap = prmaps; prmap -> pr_size && funcstat == 0; ++prmap)
	    {
	      fd = proc_address_to_fd ((CORE_ADDR) prmap -> pr_vaddr, 0);
	      funcstat = (*func) (fd, (CORE_ADDR) prmap -> pr_vaddr);
	      close (fd);
	    }
	}
    }
  return (funcstat);
}

#if 0	/* Currently unused */
/*

GLOBAL FUNCTION

	proc_base_address -- find base address for segment containing address

SYNOPSIS

	CORE_ADDR proc_base_address (CORE_ADDR addr)

DESCRIPTION

	Given an address of a location in the inferior, find and return
	the base address of the mapped segment containing that address.

	This is used for example, by the shared library support code,
	where we have the pc value for some location in the shared library
	where we are stopped, and need to know the base address of the
	segment containing that address.
*/

CORE_ADDR
proc_base_address (addr)
     CORE_ADDR addr;
{
  int nmap;
  struct prmap *prmaps;
  struct prmap *prmap;
  CORE_ADDR baseaddr = 0;

  if (pi.valid && (ioctl (pi.fd, PIOCNMAP, &nmap) == 0))
    {
      prmaps = (struct prmap *) alloca ((nmap + 1) * sizeof (*prmaps));
      if (ioctl (pi.fd, PIOCMAP, prmaps) == 0)
	{
	  for (prmap = prmaps; prmap -> pr_size; ++prmap)
	    {
	      if ((prmap -> pr_vaddr <= (caddr_t) addr) &&
		  (prmap -> pr_vaddr + prmap -> pr_size > (caddr_t) addr))
		{
		  baseaddr = (CORE_ADDR) prmap -> pr_vaddr;
		  break;
		}
	    }
	}
    }
  return (baseaddr);
}

#endif	/* 0 */

/*

LOCAL FUNCTION

	proc_address_to_fd -- return open fd for file mapped to address

SYNOPSIS

	int proc_address_to_fd (CORE_ADDR addr, complain)

DESCRIPTION

	Given an address in the current inferior's address space, use the
	/proc interface to find an open file descriptor for the file that
	this address was mapped in from.  Return -1 if there is no current
	inferior.  Print a warning message if there is an inferior but
	the address corresponds to no file (IE a bogus address).

*/

static int
proc_address_to_fd (addr, complain)
     CORE_ADDR addr;
     int complain;
{
  int fd = -1;

  if (pi.valid)
    {
      if ((fd = ioctl (pi.fd, PIOCOPENM, (caddr_t *) &addr)) < 0)
	{
	  if (complain)
	    {
	      print_sys_errmsg (pi.pathname, errno);
	      warning ("can't find mapped file for address 0x%x", addr);
	    }
	}
    }
  return (fd);
}


/* Attach to process PID, then initialize for debugging it
   and wait for the trace-trap that results from attaching.  */

static void
procfs_attach (args, from_tty)
     char *args;
     int from_tty;
{
  char *exec_file;
  int pid;

  if (!args)
    error_no_arg ("process-id to attach");

  pid = atoi (args);

  if (pid == getpid())		/* Trying to masturbate? */
    error ("I refuse to debug myself!");

  if (from_tty)
    {
      exec_file = (char *) get_exec_file (0);

      if (exec_file)
	printf ("Attaching program `%s', pid %d\n", exec_file, pid);
      else
	printf ("Attaching pid %d\n", pid);

      fflush (stdout);
    }

  do_attach (pid);