kernel/system/do_copy.c
/* The kernel call implemented in this file:
 *   m_type:	SYS_VIRCOPY, SYS_PHYSCOPY
 *
 * The parameters for this kernel call are:
 *    m5_l1:	CP_SRC_ADDR		source offset within segment
 *    m5_i1:	CP_SRC_ENDPT		source process number
 *    m5_l2:	CP_DST_ADDR		destination offset within segment
 *    m5_i2:	CP_DST_ENDPT		destination process number
 *    m5_l3:	CP_NR_BYTES		number of bytes to copy
 */

#include "kernel/system.h"
#include <minix/type.h>

#if (USE_VIRCOPY || USE_PHYSCOPY)

/*===========================================================================*
 *				do_copy					     *
 *===========================================================================*/
int do_copy(struct proc * caller, message * m_ptr)
{
/* Handle sys_vircopy() and sys_physcopy().  Copy data using virtual or
 * physical addressing. Although a single handler function is used, there 
 * are two different kernel calls so that permissions can be checked. 
 */
  struct vir_addr vir_addr[2];	/* virtual source and destination address */
  phys_bytes bytes;		/* number of bytes to copy */
  int i;

#if 0
  if (caller->p_endpoint != PM_PROC_NR && caller->p_endpoint != VFS_PROC_NR &&
	caller->p_endpoint != RS_PROC_NR && caller->p_endpoint != MEM_PROC_NR &&
	caller->p_endpoint != VM_PROC_NR)
  {
	static int first=1;
	if (first)
	{
		first= 0;
		printf(
"do_copy: got request from %d (source %d, destination %d)\n",
			caller->p_endpoint,
			m_ptr->CP_SRC_ENDPT,
			m_ptr->CP_DST_ENDPT);
	}
  }
#endif

  /* Dismember the command message. */
  vir_addr[_SRC_].proc_nr_e = m_ptr->CP_SRC_ENDPT;
  vir_addr[_DST_].proc_nr_e = m_ptr->CP_DST_ENDPT;

  vir_addr[_SRC_].offset = (vir_bytes) m_ptr->CP_SRC_ADDR;
  vir_addr[_DST_].offset = (vir_bytes) m_ptr->CP_DST_ADDR;
  bytes = (phys_bytes) m_ptr->CP_NR_BYTES;

  /* Now do some checks for both the source and destination virtual address.
   * This is done once for _SRC_, then once for _DST_. 
   */
  for (i=_SRC_; i<=_DST_; i++) {
	int p;
      /* Check if process number was given implictly with SELF and is valid. */
      if (vir_addr[i].proc_nr_e == SELF)
	vir_addr[i].proc_nr_e = caller->p_endpoint;
      if (vir_addr[i].proc_nr_e != NONE) {
	if(! isokendpt(vir_addr[i].proc_nr_e, &p)) {
	  printf("do_copy: %d: %d not ok endpoint\n", i, vir_addr[i].proc_nr_e);
          return(EINVAL); 
        }
      }
  }

  /* Check for overflow. This would happen for 64K segments and 16-bit 
   * vir_bytes. Especially copying by the PM on do_fork() is affected. 
   */
  if (bytes != (phys_bytes) (vir_bytes) bytes) return(E2BIG);

  /* Now try to make the actual virtual copy. */
  return( virtual_copy_vmcheck(caller, &vir_addr[_SRC_],
			  	&vir_addr[_DST_], bytes) );
}
#endif /* (USE_VIRCOPY || USE_PHYSCOPY) */

