Exemplos de max_select_fd em C++ (Cpp)

Exemplo n.º 1

Arquivo: select.c Projeto: Antonio-Zhou/Linux-2.6.11

int do_select(int n, fd_set_bits *fds, long *timeout)
{
	struct poll_wqueues table;
	poll_table *wait;
	int retval, i;
	long __timeout = *timeout;

 	spin_lock(&current->files->file_lock);
	retval = max_select_fd(n, fds);
	spin_unlock(&current->files->file_lock);

	if (retval < 0)
		return retval;
	n = retval;

	poll_initwait(&table);
	wait = &table.pt;
	if (!__timeout)
		wait = NULL;
	retval = 0;
	for (;;) {
		unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp;

		set_current_state(TASK_INTERRUPTIBLE);

		inp = fds->in; outp = fds->out; exp = fds->ex;
		rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex;

		for (i = 0; i < n; ++rinp, ++routp, ++rexp) {
			unsigned long in, out, ex, all_bits, bit = 1, mask, j;
			unsigned long res_in = 0, res_out = 0, res_ex = 0;
			struct file_operations *f_op = NULL;
			struct file *file = NULL;

			in = *inp++; out = *outp++; ex = *exp++;
			all_bits = in | out | ex;
			if (all_bits == 0) {
				i += __NFDBITS;
				continue;
			}

			for (j = 0; j < __NFDBITS; ++j, ++i, bit <<= 1) {
				if (i >= n)
					break;
				if (!(bit & all_bits))
					continue;
				file = fget(i);
				if (file) {
					f_op = file->f_op;
					mask = DEFAULT_POLLMASK;
					if (f_op && f_op->poll)
						mask = (*f_op->poll)(file, retval ? NULL : wait);
					fput(file);
					if ((mask & POLLIN_SET) && (in & bit)) {
						res_in |= bit;
						retval++;
					}
					if ((mask & POLLOUT_SET) && (out & bit)) {
						res_out |= bit;
						retval++;
					}
					if ((mask & POLLEX_SET) && (ex & bit)) {
						res_ex |= bit;
						retval++;
					}
				}
				cond_resched();
			}
			if (res_in)
				*rinp = res_in;
			if (res_out)
				*routp = res_out;
			if (res_ex)
				*rexp = res_ex;
		}
		wait = NULL;
		if (retval || !__timeout || signal_pending(current))
			break;
		if(table.error) {
			retval = table.error;
			break;
		}
		__timeout = schedule_timeout(__timeout);
	}
	__set_current_state(TASK_RUNNING);

	poll_freewait(&table);

	/*
	 * Up-to-date the caller timeout.
	 */
	*timeout = __timeout;
	return retval;
}

Exemplo n.º 2

int do_select(int n, fd_set_bits *fds, long *timeout)
{
	poll_table table, *wait;
	int retval, i, off;
	long __timeout = *timeout;

 	read_lock(&current->files->file_lock);
	retval = max_select_fd(n, fds);
	read_unlock(&current->files->file_lock);

	if (retval < 0)
		return retval;
	n = retval;

	poll_initwait(&table);
	wait = &table;
	if (!__timeout)
		wait = NULL;
	retval = 0;
	for (;;) {
		set_current_state(TASK_INTERRUPTIBLE);
		for (i = 0 ; i < n; i++) {
			unsigned long bit = BIT(i);
			unsigned long mask;
			struct file *file;

			off = i / __NFDBITS;
			if (!(bit & BITS(fds, off)))
				continue;
			file = fget(i);
			mask = POLLNVAL;
			if (file) {
				mask = DEFAULT_POLLMASK;
				if (file->f_op && file->f_op->poll)
					mask = file->f_op->poll(file, wait);
				fput(file);
			}
			if ((mask & POLLIN_SET) && ISSET(bit, __IN(fds,off))) {
				SET(bit, __RES_IN(fds,off));
				retval++;
				wait = NULL;
			}
			if ((mask & POLLOUT_SET) && ISSET(bit, __OUT(fds,off))) {
				SET(bit, __RES_OUT(fds,off));
				retval++;
				wait = NULL;
			}
			if ((mask & POLLEX_SET) && ISSET(bit, __EX(fds,off))) {
				SET(bit, __RES_EX(fds,off));
				retval++;
				wait = NULL;
			}
		}
		wait = NULL;
		if (retval || !__timeout || signal_pending(current))
			break;
		if(table.error) {
			retval = table.error;
			break;
		}
		__timeout = schedule_timeout(__timeout);
	}
	current->state = TASK_RUNNING;

	poll_freewait(&table);

	/*
	 * Up-to-date the caller timeout.
	 */
	*timeout = __timeout;
	return retval;
}