syscall.c

Simple Operating Systems （简称SOS）是一个可以运行在X86平台上（包括QEMU

/* Copyright (C) 2005  David Decotigny

   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 <sos/thread.h>
#include <sos/kmalloc.h>
#include <sos/klibc.h>
#include <drivers/bochs.h>

#include <hwcore/cpu_context.h>
#include <sos/uaccess.h>
#include "syscall.h"


/**
 * THE syscall entry point
 */
sos_ret_t sos_do_syscall(int syscall_id,
			 const struct sos_cpu_state *user_ctxt)
{
  sos_ret_t retval;

  switch(syscall_id)
    {
    case SOS_SYSCALL_ID_EXIT:
      {
	unsigned int status;
	retval = sos_syscall_get1arg(user_ctxt, & status);
	if (SOS_OK != retval)
	  break;
	sos_thread_exit();
	retval = -SOS_EFATAL; /* Not reached */
      }
      break;
    case SOS_SYSCALL_ID_BOCHS_WRITE:
      {
	sos_uaddr_t user_str;
	sos_size_t len;
	char * str;
	retval = sos_syscall_get2args(user_ctxt, & user_str, & len);
	if (SOS_OK != retval)
	  break;

	str = (char*)sos_kmalloc(len + 1, 0);
	if (str)
	  {
	    retval = sos_strzcpy_from_user(str, user_str, len+1);
	    str[len] = '\0';
	    if (SOS_OK == retval)
	      {
		sos_bochs_printf("THR 0x%x: ",
				 (unsigned)sos_thread_get_current());
		retval = sos_bochs_putstring(str);
		retval = len;
	      }
	    sos_kfree((sos_vaddr_t)str);
	  }
	else
	  retval = -SOS_ENOMEM;
      }
      break;


      /* ***********************************************
       * Debug syscalls (will be removed in the future)
       */


      /**
       * Syscall 4012: hexdump of a user-space memory region
       * args: addr_start size, retval=ignored
       */
    case 4012:
      {
	sos_uaddr_t user_str;
	unsigned int len;
	unsigned char * str;

	retval = sos_syscall_get2args(user_ctxt, & user_str, & len);
	if (SOS_OK != retval)
	  break;

	str = (char*)sos_kmalloc(len + 1, 0);
	if (str)
	  {
	    int i;
	    sos_bochs_printf("Hexdump(0x%x, %d):\n", user_str, len);
	    retval = sos_memcpy_from_user((sos_vaddr_t) str, user_str, len);
	    sos_bochs_printf("  (Successfully copied %d out of %d)\n",
			     retval, len);

	    for (i = 0 ; i < retval ; i++)
	      {
		if ((i % 32) == 0)
		  sos_bochs_printf("%x:", i);
		sos_bochs_printf(" %x", str[i]);
		if (((i+1) % 32) == 0)
		  sos_bochs_printf("\n");
	      }
	    if (i % 32)
	      sos_bochs_printf("\n");

	    sos_kfree((sos_vaddr_t)str);
	  }
	else
	  retval = -SOS_ENOMEM;
      }
      break;


      /**
       * Syscall 4008: dump the list of processes in the system
       * args: none, retval=ignored
       */
    case 4008:
      {
	extern void sos_process_dumplist(void);
	sos_process_dumplist();
	retval = SOS_OK;
      }
      break;

    default:
      sos_bochs_printf("Syscall: UNKNOWN[%d]\n", syscall_id);
      retval = -SOS_ENOSUP;
    }
  
  return retval;
}