wait.c File Reference

#include <xinu.h>

Include dependency graph for wait.c:

Go to the source code of this file.

Functions
syscall	wait (sid32 sem)

Function Documentation

wait()

syscall wait

(

sid32

sem

)

Definition at line 9 of file wait.c.

References currpid, disable(), enqueue(), isbadsem, OK, PR_WAIT, proctab, procent::prsem, procent::prstate, resched(), restore(), S_FREE, sentry::scount, semtab, sentry::squeue, sentry::sstate, and SYSERR.

Referenced by ethread(), ethwrite(), getbuf(), ipout(), lflclose(), lflcontrol(), lflgetc(), lflputc(), lflseek(), lfsetup(), lfsopen(), mark(), ptrecv(), ptsend(), rdsbufalloc(), rdsprocess(), rflclose(), rflread(), rflseek(), rflwrite(), rfscontrol(), rfsopen(), ttycontrol(), ttygetc(), ttyputc(), and xsh_ls().

{
    intmask mask;           /* Saved interrupt mask     */
    struct  procent *prptr;     /* Ptr to process's table entry */
    struct  sentry *semptr;     /* Ptr to sempahore table entry */

    mask = disable();
    if (isbadsem(sem)) {
        restore(mask);
        return SYSERR;
    }

    semptr = &semtab[sem];
    if (semptr->sstate == S_FREE) {
        restore(mask);
        return SYSERR;
    }

    if (--(semptr->scount) < 0) {       /* If caller must block */
        prptr = &proctab[currpid];
        prptr->prstate = PR_WAIT;   /* Set state to waiting */
        prptr->prsem = sem;     /* Record semaphore ID  */
        enqueue(currpid,semptr->squeue);/* Enqueue on semaphore */
        resched();          /*   and reschedule */
    }

    restore(mask);
    return OK;
}

Here is the call graph for this function:

Here is the caller graph for this function: