Function fdclose

freebsd/kern/kern_descrip.c:2757–2769

* If a specific file object occupies a specific file descriptor, close the * file descriptor entry and drop a reference on the file object. This is a * convenience function to handle a subsequent error in a function that calls * falloc() that handles the race that another thread might have closed the * file descriptor out from under the thread creating the file object. */

 * file descriptor out from under the thread creating the file object.
 */
void
fdclose(struct thread *td, struct file *fp, int idx)
{
	struct filedesc *fdp = td->td_proc->p_fd;

	FILEDESC_XLOCK(fdp);
	if (fdp->fd_ofiles[idx].fde_file == fp) {
		fdfree(fdp, idx);
		FILEDESC_XUNLOCK(fdp);
		fdrop(fp, td);
	} else
		FILEDESC_XUNLOCK(fdp);
}

/*
 * Close any files on exec?