kill.c

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#include <xinu.h>

syscall kill(pid32 pid)
{
    intmask mask;          /* Saved interrupt mask      */
    struct procent *prptr; /* Ptr to process's table entry  */
    int32 i;               /* Index into descriptors    */

    mask = disable();
    if (isbadpid(pid) || (pid == NULLPROC) || ((prptr = &proctab[pid])->prstate) == PR_FREE)
    {
        restore(mask);
        return SYSERR;
    }

    if (--prcount <= 1)
    { /* Last user process completes    */
        xdone();
    }

    send(prptr->prparent, pid);
    for (i = 0; i < 3; i++)
    {
        close(prptr->prdesc[i]);
    }
    freestk(prptr->prstkbase, prptr->prstklen);

    switch (prptr->prstate)
    {
    case PR_CURR:
        prptr->prstate = PR_FREE; /* Suicide */
        resched();

    case PR_SLEEP:
    case PR_RECTIM:
        unsleep(pid);
        prptr->prstate = PR_FREE;
        break;

    case PR_WAIT:
        semtab[prptr->prsem].scount++;
        /* Fall through */

    case PR_READY:
        getitem(pid); /* Remove from queue */
                      /* Fall through */

    default:
        prptr->prstate = PR_FREE;
    }

    restore(mask);
    return OK;
}