lflcontrol.c File Reference

#include <xinu.h>

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Functions
devcall	lflcontrol (struct dentry *devptr, int32 func, int32 arg1, int32 arg2)

Function Documentation

lflcontrol()

devcall lflcontrol	(	struct dentry *	devptr,
		int32	func,
		int32	arg1,
		int32	arg2
	)

Definition at line 9 of file lflcontrol.c.

References dentry::dvminor, kprintf(), LF_CTL_TRUNC, Lf_data, lfdata::lf_mutex, LF_USED, lfltab, lflcblk::lfmutex, lflcblk::lfstate, lftruncate(), signal(), SYSERR, and wait().

{
    struct  lflcblk *lfptr;     /* Ptr to open file table entry */
    int32   retval;         /* Return value from func. call */

    /* Obtain exclusive use of the file */

    lfptr = &lfltab[devptr->dvminor];
    wait(lfptr->lfmutex);

    /* If file is not open, return an error */

    if (lfptr->lfstate != LF_USED) {
        signal(lfptr->lfmutex);
        return SYSERR;
    }

    switch (func) {

    /* Truncate a file */

    case LF_CTL_TRUNC:
        wait(Lf_data.lf_mutex);
        retval = lftruncate(lfptr);
        signal(Lf_data.lf_mutex);
        signal(lfptr->lfmutex);
        return retval;  

    default:
        kprintf("lfcontrol: function %d not valid\n\r", func);
        signal(lfptr->lfmutex);
        return SYSERR;
    }
}

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