| /* |
| * |
| * Copyright 1999 Digi International (www.digi.com) |
| * James Puzzo <jamesp at digi dot com> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2, or (at your option) |
| * any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED; without even the |
| * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR |
| * PURPOSE. See the GNU General Public License for more details. |
| * |
| */ |
| |
| /* |
| * |
| * Filename: |
| * |
| * dgrp_common.c |
| * |
| * Description: |
| * |
| * Definitions of global variables and functions which are either |
| * shared by the tty, mon, and net drivers; or which cross them |
| * functionally (like the poller). |
| * |
| * Author: |
| * |
| * James A. Puzzo |
| * |
| */ |
| |
| #include <linux/errno.h> |
| #include <linux/tty.h> |
| #include <linux/sched.h> |
| #include <linux/cred.h> |
| |
| #include "dgrp_common.h" |
| |
| /** |
| * dgrp_carrier -- check for carrier change state and act |
| * @ch: struct ch_struct * |
| */ |
| void dgrp_carrier(struct ch_struct *ch) |
| { |
| struct nd_struct *nd; |
| |
| int virt_carrier = 0; |
| int phys_carrier = 0; |
| |
| /* fix case when the tty has already closed. */ |
| |
| if (!ch) |
| return; |
| nd = ch->ch_nd; |
| if (!nd) |
| return; |
| |
| /* |
| * If we are currently waiting to determine the status of the port, |
| * we don't yet know the state of the modem lines. As a result, |
| * we ignore state changes when we are waiting for the modem lines |
| * to be established. We know, as a result of code in dgrp_net_ops, |
| * that we will be called again immediately following the reception |
| * of the status message with the true modem status flags in it. |
| */ |
| if (ch->ch_expect & RR_STATUS) |
| return; |
| |
| /* |
| * If CH_HANGUP is set, we gotta keep trying to get all the processes |
| * that have the port open to close the port. |
| * So lets just keep sending a hangup every time we get here. |
| */ |
| if ((ch->ch_flag & CH_HANGUP) && |
| (ch->ch_tun.un_open_count > 0)) |
| tty_hangup(ch->ch_tun.un_tty); |
| |
| /* |
| * Compute the effective state of both the physical and virtual |
| * senses of carrier. |
| */ |
| |
| if (ch->ch_s_mlast & DM_CD) |
| phys_carrier = 1; |
| |
| if ((ch->ch_s_mlast & DM_CD) || |
| (ch->ch_digi.digi_flags & DIGI_FORCEDCD) || |
| (ch->ch_flag & CH_CLOCAL)) |
| virt_carrier = 1; |
| |
| /* |
| * Test for a VIRTUAL carrier transition to HIGH. |
| * |
| * The CH_HANGUP condition is intended to prevent any action |
| * except for close. As a result, we ignore positive carrier |
| * transitions during CH_HANGUP. |
| */ |
| if (((ch->ch_flag & CH_HANGUP) == 0) && |
| ((ch->ch_flag & CH_VIRT_CD) == 0) && |
| (virt_carrier == 1)) { |
| /* |
| * When carrier rises, wake any threads waiting |
| * for carrier in the open routine. |
| */ |
| nd->nd_tx_work = 1; |
| |
| if (waitqueue_active(&ch->ch_flag_wait)) |
| wake_up_interruptible(&ch->ch_flag_wait); |
| } |
| |
| /* |
| * Test for a PHYSICAL transition to low, so long as we aren't |
| * currently ignoring physical transitions (which is what "virtual |
| * carrier" indicates). |
| * |
| * The transition of the virtual carrier to low really doesn't |
| * matter... it really only means "ignore carrier state", not |
| * "make pretend that carrier is there". |
| */ |
| if ((virt_carrier == 0) && |
| ((ch->ch_flag & CH_PHYS_CD) != 0) && |
| (phys_carrier == 0)) { |
| /* |
| * When carrier drops: |
| * |
| * Do a Hard Hangup if that is called for. |
| * |
| * Drop carrier on all open units. |
| * |
| * Flush queues, waking up any task waiting in the |
| * line discipline. |
| * |
| * Send a hangup to the control terminal. |
| * |
| * Enable all select calls. |
| */ |
| |
| nd->nd_tx_work = 1; |
| |
| ch->ch_flag &= ~(CH_LOW | CH_EMPTY | CH_DRAIN | CH_INPUT); |
| |
| if (waitqueue_active(&ch->ch_flag_wait)) |
| wake_up_interruptible(&ch->ch_flag_wait); |
| |
| if (ch->ch_tun.un_open_count > 0) |
| tty_hangup(ch->ch_tun.un_tty); |
| |
| if (ch->ch_pun.un_open_count > 0) |
| tty_hangup(ch->ch_pun.un_tty); |
| } |
| |
| /* |
| * Make sure that our cached values reflect the current reality. |
| */ |
| if (virt_carrier == 1) |
| ch->ch_flag |= CH_VIRT_CD; |
| else |
| ch->ch_flag &= ~CH_VIRT_CD; |
| |
| if (phys_carrier == 1) |
| ch->ch_flag |= CH_PHYS_CD; |
| else |
| ch->ch_flag &= ~CH_PHYS_CD; |
| |
| } |