kernel/system/do_umap_remote.c
/* The kernel call implemented in this file:
 *   m_type:	SYS_UMAP_REMOTE
 *
 * The parameters for this kernel call are:
 *    m5_i1:	CP_SRC_PROC_NR	(process number)
 *    m5_s1:	UMAP_SEG	(segment where address is: T, D, or S)
 *    m5_l1:	CP_SRC_ADDR	(virtual address)
 *    m5_i2:	CP_DST_ENDPT	(process number of grantee to check access for)
 *    m5_l2:	CP_DST_ADDR	(returns physical address)
 *    m5_l3:	CP_NR_BYTES	(size of datastructure)
 */

#include "kernel/system.h"

#include <minix/endpoint.h>

#if USE_UMAP || USE_UMAP_REMOTE

#if ! USE_UMAP_REMOTE
#undef do_umap_remote
#endif

/*==========================================================================*
 *				do_umap_remote				    *
 *==========================================================================*/
int do_umap_remote(struct proc * caller, message * m_ptr)
{
/* Map virtual address to physical, for non-kernel processes. */
  int seg_type = m_ptr->UMAP_SEG & SEGMENT_TYPE;
  int seg_index = m_ptr->UMAP_SEG & SEGMENT_INDEX;
  vir_bytes offset = m_ptr->CP_SRC_ADDR;
  int count = m_ptr->CP_NR_BYTES;
  int endpt = (int) m_ptr->CP_SRC_ENDPT;
  endpoint_t grantee = (endpoint_t) m_ptr->CP_DST_ENDPT;
  int proc_nr, proc_nr_grantee;
  phys_bytes phys_addr = 0, lin_addr = 0;
  struct proc *targetpr;

  /* Verify process number. */
  if (endpt == SELF)
	okendpt(caller->p_endpoint, &proc_nr);
  else
	if (! isokendpt(endpt, &proc_nr))
		return(EINVAL);
  targetpr = proc_addr(proc_nr);

  /* Verify grantee endpoint */
  if (grantee == SELF) {
	grantee = caller->p_endpoint;
  } else if (grantee == NONE ||
	grantee == ANY ||
	seg_index != MEM_GRANT ||
	!isokendpt(grantee, &proc_nr_grantee)) {
	return EINVAL;
  }

  /* See which mapping should be made. */
  switch(seg_type) {
  case LOCAL_VM_SEG:
    if(seg_index == MEM_GRANT) {
	vir_bytes newoffset;
	endpoint_t newep;
	int new_proc_nr;
	cp_grant_id_t grant = (cp_grant_id_t) offset;

        if(verify_grant(targetpr->p_endpoint, grantee, grant, count,
                0, 0, &newoffset, &newep) != OK) {
                printf("SYSTEM: do_umap: verify_grant in %s, grant %d, bytes 0x%lx, failed, caller %s\n", targetpr->p_name, offset, count, caller->p_name);
		proc_stacktrace(caller);
                return EFAULT;
        }

        if(!isokendpt(newep, &new_proc_nr)) {
                printf("SYSTEM: do_umap: isokendpt failed\n");
                return EFAULT;
        }

	/* New lookup. */
	offset = newoffset;
	targetpr = proc_addr(new_proc_nr);
	seg_index = VIR_ADDR;
      }

      if(seg_index == VIR_ADDR) {
        phys_addr = lin_addr = offset;
      } else {
	printf("SYSTEM: bogus seg type 0x%lx\n", seg_index);
	return EFAULT;
      }
      if(!lin_addr) {
	printf("SYSTEM:do_umap: umap_local failed\n");
	return EFAULT;
      }
      if(vm_lookup(targetpr, lin_addr, &phys_addr, NULL) != OK) {
	printf("SYSTEM:do_umap: vm_lookup failed\n");
	return EFAULT;
      }
      if(phys_addr == 0)
	panic("vm_lookup returned zero physical address");
      break;
  default:
  	printf("umap: peculiar type\n");
  	return EINVAL;
  }

  if(vm_running && vm_lookup_range(targetpr, lin_addr, NULL, count) != count) {
	printf("SYSTEM:do_umap: not contiguous\n");
	return EFAULT;
  }

  m_ptr->CP_DST_ADDR = phys_addr;
  if(phys_addr == 0) {
	  printf("kernel: umap 0x%x done by %d / %s, pc 0x%lx, 0x%lx -> 0x%lx\n",
		seg_type, caller->p_endpoint, caller->p_name,
		caller->p_reg.pc, offset, phys_addr);
	printf("caller stack: ");
	proc_stacktrace(caller);
  }
  return (phys_addr == 0) ? EFAULT: OK;
}

#endif /* USE_UMAP || USE_UMAP_REMOTE */
