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_s1:    CP_SRC_SPACE            source virtual segment
   6  *    m5_l1:    CP_SRC_ADDR             source offset within segment
   7  *    m5_i1:    CP_SRC_ENDPT            source process number
   8  *    m5_s2:    CP_DST_SPACE            destination virtual segment
   9  *    m5_l2:    CP_DST_ADDR             destination offset within segment
  10  *    m5_i2:    CP_DST_ENDPT            destination process number
  11  *    m5_l3:    CP_NR_BYTES             number of bytes to copy
  12  */
  13
  14 #include "../system.h"
  15 #include <minix/type.h>
  16
  17 #if (USE_VIRCOPY || USE_PHYSCOPY)
  18
  19 /*===========================================================================*
  20  *                              do_copy                                      *
  21  *===========================================================================*/
  22 PUBLIC int do_copy(struct proc * caller, message * m_ptr)
  23 {
  24 /* Handle sys_vircopy() and sys_physcopy().  Copy data using virtual or
  25  * physical addressing. Although a single handler function is used, there
  26  * are two different kernel calls so that permissions can be checked.
  27  */
  28   struct vir_addr vir_addr[2];  /* virtual source and destination address */
  29   phys_bytes bytes;             /* number of bytes to copy */
  30   int i;
  31
  32 #if 0
  33   if (m_ptr->m_source != PM_PROC_NR && m_ptr->m_source != VFS_PROC_NR &&
  34         m_ptr->m_source != RS_PROC_NR && m_ptr->m_source != MEM_PROC_NR &&
  35         m_ptr->m_source != VM_PROC_NR)
  36   {
  37         static int first=1;
  38         if (first)
  39         {
  40                 first= 0;
  41                 printf(
  42 "do_copy: got request from %d (source %d, seg %d, destination %d, seg %d)\n",
  43                         m_ptr->m_source,
  44                         m_ptr->CP_SRC_ENDPT,
  45                         m_ptr->CP_SRC_SPACE,
  46                         m_ptr->CP_DST_ENDPT,
  47                         m_ptr->CP_DST_SPACE);
  48         }
  49   }
  50 #endif
  51
  52   /* Dismember the command message. */
  53   vir_addr[_SRC_].proc_nr_e = m_ptr->CP_SRC_ENDPT;
  54   vir_addr[_SRC_].segment = m_ptr->CP_SRC_SPACE;
  55   vir_addr[_SRC_].offset = (vir_bytes) m_ptr->CP_SRC_ADDR;
  56   vir_addr[_DST_].proc_nr_e = m_ptr->CP_DST_ENDPT;
  57   vir_addr[_DST_].segment = m_ptr->CP_DST_SPACE;
  58   vir_addr[_DST_].offset = (vir_bytes) m_ptr->CP_DST_ADDR;
  59   bytes = (phys_bytes) m_ptr->CP_NR_BYTES;
  60
  61   /* Now do some checks for both the source and destination virtual address.
  62    * This is done once for _SRC_, then once for _DST_.
  63    */
  64   for (i=_SRC_; i<=_DST_; i++) {
  65         int p;
  66       /* Check if process number was given implictly with SELF and is valid. */
  67       if (vir_addr[i].proc_nr_e == SELF)
  68         vir_addr[i].proc_nr_e = m_ptr->m_source;
  69       if (vir_addr[i].segment != PHYS_SEG) {
  70         if(! isokendpt(vir_addr[i].proc_nr_e, &p)) {
  71           printf("do_copy: %d: seg 0x%x, %d not ok endpoint\n",
  72                 i, vir_addr[i].segment, vir_addr[i].proc_nr_e);
  73           return(EINVAL);
  74         }
  75       }
  76
  77       /* Check if physical addressing is used without SYS_PHYSCOPY. */
  78       if ((vir_addr[i].segment & PHYS_SEG) &&
  79           m_ptr->m_type != SYS_PHYSCOPY) return(EPERM);
  80   }
  81
  82   /* Check for overflow. This would happen for 64K segments and 16-bit
  83    * vir_bytes. Especially copying by the PM on do_fork() is affected.
  84    */
  85   if (bytes != (phys_bytes) (vir_bytes) bytes) return(E2BIG);
  86
  87   /* Now try to make the actual virtual copy. */
  88   return( virtual_copy_vmcheck(caller, &vir_addr[_SRC_],
  89                                 &vir_addr[_DST_], bytes) );
  90 }
  91 #endif /* (USE_VIRCOPY || USE_PHYSCOPY) */
  92