kernel/system/do_copy.c

   1 /* The kernel call implemented in this file:
   2  *   m_type:    SYS_VIRCOPY, SYS_PHYSCOPY
   3  *
   4  * The parameters for this kernel call are:
   5  *    m5_l1:    CP_SRC_ADDR             source offset within segment
   6  *    m5_i1:    CP_SRC_ENDPT            source process number
   7  *    m5_l2:    CP_DST_ADDR             destination offset within segment
   8  *    m5_i2:    CP_DST_ENDPT            destination process number
   9  *    m5_l3:    CP_NR_BYTES             number of bytes to copy
  10  */
  11
  12 #include "kernel/system.h"
  13 #include <minix/type.h>
  14
  15 #if (USE_VIRCOPY || USE_PHYSCOPY)
  16
  17 /*===========================================================================*
  18  *                              do_copy                                      *
  19  *===========================================================================*/
  20 int do_copy(struct proc * caller, message * m_ptr)
  21 {
  22 /* Handle sys_vircopy() and sys_physcopy().  Copy data using virtual or
  23  * physical addressing. Although a single handler function is used, there
  24  * are two different kernel calls so that permissions can be checked.
  25  */
  26   struct vir_addr vir_addr[2];  /* virtual source and destination address */
  27   phys_bytes bytes;             /* number of bytes to copy */
  28   int i;
  29
  30 #if 0
  31   if (caller->p_endpoint != PM_PROC_NR && caller->p_endpoint != VFS_PROC_NR &&
  32         caller->p_endpoint != RS_PROC_NR && caller->p_endpoint != MEM_PROC_NR &&
  33         caller->p_endpoint != VM_PROC_NR)
  34   {
  35         static int first=1;
  36         if (first)
  37         {
  38                 first= 0;
  39                 printf(
  40 "do_copy: got request from %d (source %d, destination %d)\n",
  41                         caller->p_endpoint,
  42                         m_ptr->CP_SRC_ENDPT,
  43                         m_ptr->CP_DST_ENDPT);
  44         }
  45   }
  46 #endif
  47
  48   /* Dismember the command message. */
  49   vir_addr[_SRC_].proc_nr_e = m_ptr->CP_SRC_ENDPT;
  50   vir_addr[_DST_].proc_nr_e = m_ptr->CP_DST_ENDPT;
  51
  52   vir_addr[_SRC_].offset = (vir_bytes) m_ptr->CP_SRC_ADDR;
  53   vir_addr[_DST_].offset = (vir_bytes) m_ptr->CP_DST_ADDR;
  54   bytes = (phys_bytes) m_ptr->CP_NR_BYTES;
  55
  56   /* Now do some checks for both the source and destination virtual address.
  57    * This is done once for _SRC_, then once for _DST_.
  58    */
  59   for (i=_SRC_; i<=_DST_; i++) {
  60         int p;
  61       /* Check if process number was given implictly with SELF and is valid. */
  62       if (vir_addr[i].proc_nr_e == SELF)
  63         vir_addr[i].proc_nr_e = caller->p_endpoint;
  64       if (vir_addr[i].proc_nr_e != NONE) {
  65         if(! isokendpt(vir_addr[i].proc_nr_e, &p)) {
  66           printf("do_copy: %d: %d not ok endpoint\n", i, vir_addr[i].proc_nr_e);
  67           return(EINVAL);
  68         }
  69       }
  70   }
  71
  72   /* Check for overflow. This would happen for 64K segments and 16-bit
  73    * vir_bytes. Especially copying by the PM on do_fork() is affected.
  74    */
  75   if (bytes != (phys_bytes) (vir_bytes) bytes) return(E2BIG);
  76
  77   /* Now try to make the actual virtual copy. */
  78   return( virtual_copy_vmcheck(caller, &vir_addr[_SRC_],
  79                                 &vir_addr[_DST_], bytes) );
  80 }
  81 #endif /* (USE_VIRCOPY || USE_PHYSCOPY) */
  82