minix/kernel/system/do_copy.c
2010-01-19 21:19:59 +00:00

93 lines
3.2 KiB
C

/* The kernel call implemented in this file:
* m_type: SYS_VIRCOPY, SYS_PHYSCOPY
*
* The parameters for this kernel call are:
* m5_s1: CP_SRC_SPACE source virtual segment
* m5_l1: CP_SRC_ADDR source offset within segment
* m5_i1: CP_SRC_ENDPT source process number
* m5_s2: CP_DST_SPACE destination virtual segment
* m5_l2: CP_DST_ADDR destination offset within segment
* m5_i2: CP_DST_ENDPT destination process number
* m5_l3: CP_NR_BYTES number of bytes to copy
*/
#include "../system.h"
#include "../vm.h"
#include <minix/type.h>
#if (USE_VIRCOPY || USE_PHYSCOPY)
/*===========================================================================*
* do_copy *
*===========================================================================*/
PUBLIC int do_copy(m_ptr)
register message *m_ptr; /* pointer to request message */
{
/* Handle sys_vircopy() and sys_physcopy(). Copy data using virtual or
* physical addressing. Although a single handler function is used, there
* are two different kernel calls so that permissions can be checked.
*/
struct vir_addr vir_addr[2]; /* virtual source and destination address */
phys_bytes bytes; /* number of bytes to copy */
int i;
#if 0
if (m_ptr->m_source != PM_PROC_NR && m_ptr->m_source != VFS_PROC_NR &&
m_ptr->m_source != RS_PROC_NR && m_ptr->m_source != MEM_PROC_NR &&
m_ptr->m_source != VM_PROC_NR)
{
static int first=1;
if (first)
{
first= 0;
kprintf(
"do_copy: got request from %d (source %d, seg %d, destination %d, seg %d)\n",
m_ptr->m_source,
m_ptr->CP_SRC_ENDPT,
m_ptr->CP_SRC_SPACE,
m_ptr->CP_DST_ENDPT,
m_ptr->CP_DST_SPACE);
}
}
#endif
/* Dismember the command message. */
vir_addr[_SRC_].proc_nr_e = m_ptr->CP_SRC_ENDPT;
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_e = m_ptr->CP_DST_ENDPT;
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++) {
int p;
/* Check if process number was given implictly with SELF and is valid. */
if (vir_addr[i].proc_nr_e == SELF)
vir_addr[i].proc_nr_e = m_ptr->m_source;
if (vir_addr[i].segment != PHYS_SEG) {
if(! isokendpt(vir_addr[i].proc_nr_e, &p)) {
kprintf("do_copy: %d: seg 0x%x, %d not ok endpoint\n",
i, vir_addr[i].segment, vir_addr[i].proc_nr_e);
return(EINVAL);
}
}
/* Check if physical addressing is used without SYS_PHYSCOPY. */
if ((vir_addr[i].segment & PHYS_SEG) &&
m_ptr->m_type != SYS_PHYSCOPY) return(EPERM);
}
/* Check for overflow. This would happen for 64K segments and 16-bit
* vir_bytes. Especially copying by the PM on do_fork() is affected.
*/
if (bytes != (vir_bytes) bytes) return(E2BIG);
/* Now try to make the actual virtual copy. */
return( virtual_copy_vmcheck(&vir_addr[_SRC_], &vir_addr[_DST_], bytes) );
}
#endif /* (USE_VIRCOPY || USE_PHYSCOPY) */