signaln.c

Go to the documentation of this file.

#include <xinu.h>

syscall signaln(sid32 sem, int32 count)
{
    intmask mask;          /* Saved interrupt mask      */
    struct sentry *semptr; /* Ptr to sempahore table entry */

    mask = disable();
    if (isbadsem(sem) || (count < 0))
    {
        restore(mask);
        return SYSERR;
    }
    semptr = &semtab[sem];
    if (semptr->sstate == S_FREE)
    {
        restore(mask);
        return SYSERR;
    }

    resched_cntl(DEFER_START);
    for (; count > 0; count--)
    {
        if ((semptr->scount++) < 0)
        {
            ready(dequeue(semptr->squeue));
        }
    }
    resched_cntl(DEFER_STOP);
    restore(mask);
    return OK;
}