minix/kernel/arch/i386/do_readbios.c

   1 /* The kernel call implemented in this file:
   2  *   m_type:    SYS_READBIOS
   3  *
   4  * The parameters for this kernel call are:
   5  *      m_lsys_krn_readbios.size        number of bytes to copy
   6  *      m_lsys_krn_readbios.addr        absolute address in BIOS area
   7  *      m_lsys_krn_readbios.buf         buffer address in requesting process
   8  */
   9
  10 #include "kernel/system.h"
  11
  12 /*===========================================================================*
  13  *                              do_readbios                                  *
  14  *===========================================================================*/
  15 int do_readbios(struct proc * caller, message * m_ptr)
  16 {
  17   struct vir_addr src, dst;
  18   size_t len = m_ptr->m_lsys_krn_readbios.size;
  19   vir_bytes limit;
  20
  21   src.offset = m_ptr->m_lsys_krn_readbios.addr;
  22   dst.offset = m_ptr->m_lsys_krn_readbios.buf;
  23   src.proc_nr_e = NONE;
  24   dst.proc_nr_e = m_ptr->m_source;
  25
  26   limit = src.offset + len - 1;
  27
  28 #define VINRANGE(v, a, b) ((a) <= (v) && (v) <= (b))
  29 #define SUBRANGE(a,b,c,d) (VINRANGE((a), (c), (d)) && VINRANGE((b),(c),(d)))
  30 #define USERRANGE(a, b) SUBRANGE(src.offset, limit, (a), (b))
  31
  32   if(!USERRANGE(BIOS_MEM_BEGIN, BIOS_MEM_END) &&
  33      !USERRANGE(BASE_MEM_TOP, UPPER_MEM_END))
  34         return EPERM;
  35
  36   return virtual_copy_vmcheck(caller, &src, &dst, m_ptr->m_lsys_krn_readbios.size);
  37 }