44 lines
1.1 KiB
C
44 lines
1.1 KiB
C
#include "kernel/system.h"
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#include <minix/endpoint.h>
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/*===========================================================================*
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* do_schedctl *
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*===========================================================================*/
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PUBLIC int do_schedctl(struct proc * caller, message * m_ptr)
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{
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struct proc *p;
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unsigned flags;
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int proc_nr;
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/* Only system processes can change process schedulers */
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if (! (priv(caller)->s_flags & SYS_PROC))
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return(EPERM);
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/* check parameter validity */
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flags = (unsigned) m_ptr->SCHEDCTL_FLAGS;
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if (flags & ~SCHEDCTL_FLAG_KERNEL) {
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printf("do_schedctl: flags 0x%x invalid, caller=%d\n",
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flags, caller - proc);
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return EINVAL;
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}
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if (!isokendpt(m_ptr->SCHEDCTL_ENDPOINT, &proc_nr))
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return EINVAL;
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p = proc_addr(proc_nr);
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if ((flags & SCHEDCTL_FLAG_KERNEL) == SCHEDCTL_FLAG_KERNEL) {
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/* the kernel becomes the scheduler and starts
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* scheduling the process; RTS_NO_QUANTUM which was
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* previously set by sys_fork is removed
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*/
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p->p_scheduler = NULL;
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RTS_UNSET(p, RTS_NO_QUANTUM);
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} else {
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/* the caller becomes the scheduler */
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p->p_scheduler = caller;
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}
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return(OK);
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}
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