glibc/sysdeps/mach/hurd/i386/intr-msg.h

/* Machine-dependent details of interruptible RPC messaging.  i386 version.
   Copyright (C) 1995, 1996, 1997, 1999 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 Library General Public License as
   published by the Free Software Foundation; either version 2 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */


/* Note that we must mark OPTION and TIMEOUT as outputs of this operation,
   to indicate that the signal thread might mutate them as part
   of sending us to a signal handler.  */
#define INTR_MSG_TRAP(msg, option, send_size, rcv_size, rcv_name, timeout, notify) \
({									      \
  error_t err;								      \
  asm (".globl _hurd_intr_rpc_msg_do_trap\n" 				      \
       ".globl _hurd_intr_rpc_msg_in_trap\n"				      \
       ".globl _hurd_intr_rpc_msg_cx_sp\n"				      \
       ".globl _hurd_intr_rpc_msg_sp_restored\n"			      \
       "				movl %%esp, %%ecx\n"		      \
       "				leal %3, %%esp\n"		      \
       "_hurd_intr_rpc_msg_cx_sp:	movl $-25, %%eax\n"		      \
       "_hurd_intr_rpc_msg_do_trap:	lcall $7, $0 # status in %0\n"	      \
       "_hurd_intr_rpc_msg_in_trap:	movl %%ecx, %%esp\n"		      \
       "_hurd_intr_rpc_msg_sp_restored:"				      \
       : "=a" (err), "=m" (option), "=m" (timeout)			      \
       : "m" ((&msg)[-1]), "1" (option), "2" (timeout)			      \
       : "%ecx");							      \
  err;									      \
})


static void inline
INTR_MSG_BACK_OUT (struct i386_thread_state *state)
{
  extern const void _hurd_intr_rpc_msg_cx_sp;
  if (state->eip >= (natural_t) &_hurd_intr_rpc_msg_cx_sp)
    state->uesp = state->ecx;
  else
    state->ecx = state->uesp;
}

#include "hurdfault.h"

static inline int
SYSCALL_EXAMINE (struct i386_thread_state *state, int *callno)
{
  struct { unsigned int c[2]; } *p = (void *) (state->eip - 7);
  int result;
  if (_hurdsig_catch_memory_fault (p))
    return 0;
  if (result = p->c[0] == 0x0000009a && (p->c[1] & 0x00ffffff) == 0x00000700)
    /* The PC is just after an `lcall $7,$0' instruction.
       This is a system call in progress; %eax holds the call number.  */
    *callno = state->eax;
  _hurdsig_end_catch_fault ();
  return result;
}


struct mach_msg_trap_args
  {
    void *retaddr;		/* Address mach_msg_trap will return to.  */
    /* This is the order of arguments to mach_msg_trap.  */
    mach_msg_header_t *msg;
    mach_msg_option_t option;
    mach_msg_size_t send_size;
    mach_msg_size_t rcv_size;
    mach_port_t rcv_name;
    mach_msg_timeout_t timeout;
    mach_port_t notify;
  };


static inline int
MSG_EXAMINE (struct i386_thread_state *state, int *msgid,
	     mach_port_t *rcv_name, mach_port_t *send_name,
	     mach_msg_option_t *option, mach_msg_timeout_t *timeout)
{
  const struct mach_msg_trap_args *args = (const void *) state->uesp;
  mach_msg_header_t *msg;

  if (_hurdsig_catch_memory_fault (args))
    return -1;
  msg = args->msg;
  *option = args->option;
  *timeout = args->timeout;
  *rcv_name = args->rcv_name;
  _hurdsig_end_catch_fault ();

  if (msg == 0)
    {
      *send_name = MACH_PORT_NULL;
      *msgid = 0;
    }
  else
    {
      if (_hurdsig_catch_memory_fault (msg))
	return -1;
      *send_name = msg->msgh_remote_port;
      *msgid = msg->msgh_id;
      _hurdsig_end_catch_fault ();
    }

  return 0;
}