57 lines
1.3 KiB
C
57 lines
1.3 KiB
C
/* The system call implemented in this file:
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* m_type: SYS_SETPRIORITY
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*
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* The parameters for this system call are:
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* m1_i1: which
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* m1_i2: who
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* m1_i3: prio
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*/
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#include "../kernel.h"
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#include "../system.h"
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#include <minix/type.h>
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#include <sys/resource.h>
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/*===========================================================================*
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* do_setpriority *
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*===========================================================================*/
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PUBLIC int do_setpriority(message *m_ptr)
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{
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int which_proc, pri, q, niceperq;
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struct proc *which_procp;
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which_proc = m_ptr->m1_i1;
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pri = m_ptr->m1_i2;
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/* pri is currently between PRIO_MIN and PRIO_MAX. We have to
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* scale this between MIN_USER_Q and MAX_USER_Q.
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*/
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if(pri < PRIO_MIN || pri > PRIO_MAX)
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return EINVAL;
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if(which_proc < 0 || which_proc >= NR_TASKS+NR_PROCS)
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return EINVAL;
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which_procp = proc_addr(which_proc);
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q = MAX_USER_Q + (pri - PRIO_MIN) * (MIN_USER_Q-MAX_USER_Q+1) / (PRIO_MAX-PRIO_MIN+1);
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/* The below shouldn't happen. */
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if(q < MAX_USER_Q) q = MAX_USER_Q;
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if(q > MIN_USER_Q) q = MIN_USER_Q;
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/* max_priority is the base priority. */
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which_procp->p_max_priority = q;
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lock_unready(which_procp);
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which_procp->p_priority = q;
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/* Runnable? Put it (back) on its new run queue. */
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if(!which_procp->p_rts_flags)
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lock_ready(which_procp);
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return OK;
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}
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