59 lines
1.7 KiB
C
59 lines
1.7 KiB
C
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/* The kernel call implemented in this file:
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* m_type: SYS_SAFEMEMSET
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*
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* The parameters for this kernel call are:
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* SMS_DST dst endpoint
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* SMS_GID grant id
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* SMS_OFFSET offset within grant
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* SMS_PATTERN memset pattern byte
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* SMS_BYTES bytes from offset
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*/
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#include <assert.h>
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#include <minix/safecopies.h>
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#include "kernel/system.h"
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#include "kernel/kernel.h"
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/*===========================================================================*
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* do_safememset *
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*===========================================================================*/
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int do_safememset(struct proc *caller, message *m_ptr) {
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/* Implementation of the do_safememset() kernel call */
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/* Extract parameters */
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endpoint_t dst_endpt = m_ptr->SMS_DST;
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endpoint_t caller_endpt = caller->p_endpoint;
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cp_grant_id_t grantid = m_ptr->SMS_GID;
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vir_bytes g_offset = m_ptr->SMS_OFFSET;
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int pattern = m_ptr->SMS_PATTERN;
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size_t len = (size_t)m_ptr->SMS_BYTES;
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struct proc *dst_p;
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endpoint_t new_granter;
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static vir_bytes v_offset;
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int r;
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if (dst_endpt == NONE || caller_endpt == NONE)
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return EFAULT;
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if (!(dst_p = endpoint_lookup(dst_endpt)))
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return EINVAL;
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if (!(priv(dst_p) && priv(dst_p)->s_grant_table)) {
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printf("safememset: dst %d has no grant table\n", dst_endpt);
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return EINVAL;
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}
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/* Verify permission exists, memset always requires CPF_WRITE */
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r = verify_grant(dst_endpt, caller_endpt, grantid, len, CPF_WRITE,
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g_offset, &v_offset, &new_granter, NULL);
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if (r != OK) {
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printf("safememset: grant %d verify failed %d", grantid, r);
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return r;
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}
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return vm_memset(caller, new_granter, v_offset, pattern, len);
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}
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