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