Bill Pemberton | 0b52b74 | 2012-09-20 16:55:27 -0400 | [diff] [blame] | 1 | /* |
| 2 | * |
| 3 | * Copyright 1999 Digi International (www.digi.com) |
| 4 | * James Puzzo <jamesp at digi dot com> |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License as published by |
| 8 | * the Free Software Foundation; either version 2, or (at your option) |
| 9 | * any later version. |
| 10 | * |
| 11 | * This program is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED; without even the |
| 13 | * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR |
| 14 | * PURPOSE. See the GNU General Public License for more details. |
| 15 | * |
| 16 | */ |
| 17 | |
| 18 | /* |
| 19 | * |
| 20 | * Filename: |
| 21 | * |
| 22 | * dgrp_common.c |
| 23 | * |
| 24 | * Description: |
| 25 | * |
| 26 | * Definitions of global variables and functions which are either |
| 27 | * shared by the tty, mon, and net drivers; or which cross them |
| 28 | * functionally (like the poller). |
| 29 | * |
| 30 | * Author: |
| 31 | * |
| 32 | * James A. Puzzo |
| 33 | * |
| 34 | */ |
| 35 | |
| 36 | #include <linux/errno.h> |
| 37 | #include <linux/tty.h> |
| 38 | #include <linux/sched.h> |
| 39 | #include <linux/cred.h> |
| 40 | |
| 41 | #include "dgrp_common.h" |
| 42 | |
| 43 | /** |
| 44 | * dgrp_carrier -- check for carrier change state and act |
| 45 | * @ch: struct ch_struct * |
| 46 | */ |
| 47 | void dgrp_carrier(struct ch_struct *ch) |
| 48 | { |
| 49 | struct nd_struct *nd; |
| 50 | |
| 51 | int virt_carrier = 0; |
| 52 | int phys_carrier = 0; |
| 53 | |
| 54 | /* fix case when the tty has already closed. */ |
| 55 | |
| 56 | if (!ch) |
| 57 | return; |
| 58 | nd = ch->ch_nd; |
| 59 | if (!nd) |
| 60 | return; |
| 61 | |
| 62 | /* |
| 63 | * If we are currently waiting to determine the status of the port, |
| 64 | * we don't yet know the state of the modem lines. As a result, |
| 65 | * we ignore state changes when we are waiting for the modem lines |
| 66 | * to be established. We know, as a result of code in dgrp_net_ops, |
| 67 | * that we will be called again immediately following the reception |
| 68 | * of the status message with the true modem status flags in it. |
| 69 | */ |
| 70 | if (ch->ch_expect & RR_STATUS) |
| 71 | return; |
| 72 | |
| 73 | /* |
| 74 | * If CH_HANGUP is set, we gotta keep trying to get all the processes |
| 75 | * that have the port open to close the port. |
| 76 | * So lets just keep sending a hangup every time we get here. |
| 77 | */ |
| 78 | if ((ch->ch_flag & CH_HANGUP) && |
| 79 | (ch->ch_tun.un_open_count > 0)) |
| 80 | tty_hangup(ch->ch_tun.un_tty); |
| 81 | |
| 82 | /* |
| 83 | * Compute the effective state of both the physical and virtual |
| 84 | * senses of carrier. |
| 85 | */ |
| 86 | |
| 87 | if (ch->ch_s_mlast & DM_CD) |
| 88 | phys_carrier = 1; |
| 89 | |
| 90 | if ((ch->ch_s_mlast & DM_CD) || |
| 91 | (ch->ch_digi.digi_flags & DIGI_FORCEDCD) || |
| 92 | (ch->ch_flag & CH_CLOCAL)) |
| 93 | virt_carrier = 1; |
| 94 | |
| 95 | /* |
| 96 | * Test for a VIRTUAL carrier transition to HIGH. |
| 97 | * |
| 98 | * The CH_HANGUP condition is intended to prevent any action |
| 99 | * except for close. As a result, we ignore positive carrier |
| 100 | * transitions during CH_HANGUP. |
| 101 | */ |
| 102 | if (((ch->ch_flag & CH_HANGUP) == 0) && |
| 103 | ((ch->ch_flag & CH_VIRT_CD) == 0) && |
| 104 | (virt_carrier == 1)) { |
| 105 | /* |
| 106 | * When carrier rises, wake any threads waiting |
| 107 | * for carrier in the open routine. |
| 108 | */ |
| 109 | nd->nd_tx_work = 1; |
| 110 | |
| 111 | if (waitqueue_active(&ch->ch_flag_wait)) |
| 112 | wake_up_interruptible(&ch->ch_flag_wait); |
| 113 | } |
| 114 | |
| 115 | /* |
| 116 | * Test for a PHYSICAL transition to low, so long as we aren't |
| 117 | * currently ignoring physical transitions (which is what "virtual |
| 118 | * carrier" indicates). |
| 119 | * |
| 120 | * The transition of the virtual carrier to low really doesn't |
| 121 | * matter... it really only means "ignore carrier state", not |
| 122 | * "make pretend that carrier is there". |
| 123 | */ |
| 124 | if ((virt_carrier == 0) && |
| 125 | ((ch->ch_flag & CH_PHYS_CD) != 0) && |
| 126 | (phys_carrier == 0)) { |
| 127 | /* |
| 128 | * When carrier drops: |
| 129 | * |
| 130 | * Do a Hard Hangup if that is called for. |
| 131 | * |
| 132 | * Drop carrier on all open units. |
| 133 | * |
| 134 | * Flush queues, waking up any task waiting in the |
| 135 | * line discipline. |
| 136 | * |
| 137 | * Send a hangup to the control terminal. |
| 138 | * |
| 139 | * Enable all select calls. |
| 140 | */ |
| 141 | |
| 142 | nd->nd_tx_work = 1; |
| 143 | |
| 144 | ch->ch_flag &= ~(CH_LOW | CH_EMPTY | CH_DRAIN | CH_INPUT); |
| 145 | |
| 146 | if (waitqueue_active(&ch->ch_flag_wait)) |
| 147 | wake_up_interruptible(&ch->ch_flag_wait); |
| 148 | |
| 149 | if (ch->ch_tun.un_open_count > 0) |
| 150 | tty_hangup(ch->ch_tun.un_tty); |
| 151 | |
| 152 | if (ch->ch_pun.un_open_count > 0) |
| 153 | tty_hangup(ch->ch_pun.un_tty); |
| 154 | } |
| 155 | |
| 156 | /* |
| 157 | * Make sure that our cached values reflect the current reality. |
| 158 | */ |
| 159 | if (virt_carrier == 1) |
| 160 | ch->ch_flag |= CH_VIRT_CD; |
| 161 | else |
| 162 | ch->ch_flag &= ~CH_VIRT_CD; |
| 163 | |
| 164 | if (phys_carrier == 1) |
| 165 | ch->ch_flag |= CH_PHYS_CD; |
| 166 | else |
| 167 | ch->ch_flag &= ~CH_PHYS_CD; |
| 168 | |
| 169 | } |