minix/kernel/system/old/do_vircopy.c

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2005-04-21 16:53:53 +02:00
/* The system call implemented in this file:
* m_type: SYS_VIRCOPY
*
* The parameters for this system call are:
* m5_c1: CP_SRC_SPACE
* m5_l1: CP_SRC_ADDR
* m5_i1: CP_SRC_PROC_NR
* m5_c2: CP_DST_SPACE
* m5_l2: CP_DST_ADDR
* m5_i2: CP_DST_PROC_NR
* m5_l3: CP_NR_BYTES
*/
#include "../kernel.h"
#include "../system.h"
/*===========================================================================*
* do_vircopy *
*===========================================================================*/
PUBLIC int do_vircopy(m_ptr)
register message *m_ptr; /* pointer to request message */
{
/* Handle sys_vircopy(). Copy data by using virtual addressing. */
struct vir_addr vir_addr[2]; /* virtual source and destination address */
vir_bytes bytes; /* number of bytes to copy */
int i;
/* Dismember the command message. */
vir_addr[_SRC_].proc_nr = m_ptr->CP_SRC_PROC_NR;
vir_addr[_SRC_].segment = m_ptr->CP_SRC_SPACE;
vir_addr[_SRC_].offset = (vir_bytes) m_ptr->CP_SRC_ADDR;
vir_addr[_DST_].proc_nr = m_ptr->CP_DST_PROC_NR;
vir_addr[_DST_].segment = m_ptr->CP_DST_SPACE;
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++) {
/* Check if process number was given implictly with SELF and is valid. */
if (vir_addr[i].proc_nr == SELF) vir_addr[i].proc_nr = m_ptr->m_source;
if (! isokprocn(vir_addr[i].proc_nr)) {
kprintf("do_vircopy: illegal proc nr\n",NO_ARG);
return(EINVAL);
}
/* Copying from or to special segments can only done by the owner. */
if ((vir_addr[i].segment & SEGMENT_TYPE) != LOCAL_SEG &&
vir_addr[i].proc_nr != m_ptr->m_source) {
kprintf("do_vircopy: special seg permission denied\n", NO_ARG);
return(EPERM);
}
}
/* Check for overflow. This would happen for 64K segments and 16-bit
* vir_bytes. Especially copying by the MM on do_fork() is affected.
*/
if (bytes != (vir_bytes) bytes) {
kprintf("do_vircopy: overflow\n", NO_ARG);
return(E2BIG);
}
/* Now try to make the actual virtual copy. */
return( virtual_copy(&vir_addr[_SRC_], &vir_addr[_DST_], bytes) );
}