Add visual or audible alert support on connect/disconnect

The feature is detailed via the following option:

 --alert none|bell|blink

     Set alert action on connect/disconnect.

     It will sound the bell once or blink once on successful connect.
     Likewise it will sound the bell twice or blink twice on disconnect.

     Default value is "none" for no alert.

example/tiorc

@@ -30,6 +30,7 @@ color = 9
 baudrate = 115200
 tty = /dev/serial/by-id/usb-Silicon_Labs_CP2105_Dual_USB_to_UART_Bridge_Controller_01093176-if01-port0
 line-pulse-duration = DTR=200,RTS=300,RI=50
+alert = bell
 color = 10
 
 [tincan]

man/tio.1.in

@@ -256,6 +256,16 @@ Receive data even while sending data
 If defining more than one key or key value pair, they must be comma separated.
 .RE
 
+.TP
+.BR "\-\-alert none|bell|blink"
+
+Set alert action on connect/disconnect.
+
+It will sound the bell once or blink once on successful connect. Likewise it
+will sound the bell twice or blink twice on disconnect.
+
+Default value is "none".
+
 .TP
 .BR \-v ", " \-\-version
 
@@ -389,6 +399,8 @@ Set line response timeout
 Enable RS-485 mode
 .IP "\fBrs-485-config"
 Set RS-485 configuration
+.IP "\fBalert"
+Set alert action on connect/disconnect
 
 .SH "CONFIGURATION FILE EXAMPLES"
 

src/alert.c

@@ -0,0 +1,110 @@
+/*
+ * tio - a simple serial terminal I/O tool
+ *
+ * Copyright (c) 2014-2022  Martin Lund
+ *
+ * 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
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#include "config.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include "error.h"
+#include "print.h"
+#include "options.h"
+
+enum alert_t alert_option_parse(const char *arg)
+{
+    enum alert_t alert = option.alert; // Default
+
+    if (arg != NULL)
+    {
+        if (strcmp(arg, "none") == 0)
+        {
+            return ALERT_NONE;
+        }
+        else if (strcmp(arg, "bell") == 0)
+        {
+            return ALERT_BELL;
+        }
+        else if (strcmp(arg, "blink") == 0)
+        {
+            return ALERT_BLINK;
+        }
+    }
+
+    return alert;
+}
+
+void blink_background(void)
+{
+    // Turn on reverse video
+    printf("\e[?5h");
+    fflush(stdout);
+
+    usleep(200*1000);
+
+    // Turn on normal video
+    printf("\e[?5l");
+    fflush(stdout);
+}
+
+void sound_bell(void)
+{
+    // Audio bell
+    printf("\a");
+    fflush(stdout);
+}
+
+void alert_connect(void)
+{
+    switch (option.alert)
+    {
+        case ALERT_NONE:
+            break;
+        case ALERT_BELL:
+            sound_bell();
+            break;
+        case ALERT_BLINK:
+            blink_background();
+            break;
+        default:
+            break;
+    }
+}
+
+void alert_disconnect(void)
+{
+    switch (option.alert)
+    {
+        case ALERT_NONE:
+            break;
+        case ALERT_BELL:
+            sound_bell();
+            usleep(200*1000);
+            sound_bell();
+            break;
+        case ALERT_BLINK:
+            blink_background();
+            usleep(200*1000);
+            blink_background();
+            break;
+        default:
+            break;
+    }
+}

src/alert.h

@@ -0,0 +1,33 @@
+/*
+ * tio - a simple serial terminal I/O tool
+ *
+ * Copyright (c) 2014-2022  Martin Lund
+ *
+ * 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
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#pragma once
+
+enum alert_t
+{
+    ALERT_NONE,
+    ALERT_BELL,
+    ALERT_BLINK,
+    ALERT_END,
+};
+
+void alert_connect(void);
+void alert_disconnect(void);

src/bash-completion/tio.in

@@ -29,11 +29,12 @@ _tio()
           -L --list-devices \
           -c --color \
           -S --socket \
+          -x --hexadecimal \
           -r --response-wait \
              --response-timeout \
              --rs-485 \
              --rs-485-config \
-          -x --hexadecimal \
+             --alert \
           -v --version \
           -h --help"
 
@@ -116,6 +117,10 @@ _tio()
             COMPREPLY=( $(compgen -W "unix: inet: inet6:" -- ${cur}) )
             return 0
             ;;
+        -x | --hexadecimal)
+            COMPREPLY=( $(compgen -W "${opts}" -- ${cur}) )
+            return 0
+            ;;
         -r | --response-wait)
             COMPREPLY=( $(compgen -W "${opts}" -- ${cur}) )
             return 0
@@ -132,8 +137,8 @@ _tio()
             COMPREPLY=( $(compgen -W "RTS_ON_SEND RTS_AFTER_SEND RTS_DELAY_BEFORE_SEND RTS_DELAY_AFTER_SEND RX_DURING_TX"  -- ${cur}) )
             return 0
             ;;
-        -x | --hexadecimal)
-            COMPREPLY=( $(compgen -W "${opts}" -- ${cur}) )
+        --alert)
+            COMPREPLY=( $(compgen -W "none bell blink"  -- ${cur}) )
             return 0
             ;;
         -v | --version)

src/configfile.c

@@ -280,8 +280,12 @@ static int data_handler(void *user, const char *section, const char *name,
         {
             rs485_parse_config(value);
         }
-
+        else if (!strcmp(name, "alert"))
+        {
+            option.alert = alert_option_parse(value);
+        }
     }
+
     return 0;
 }
 

src/meson.build

@@ -15,7 +15,8 @@ tio_sources = [
   'signals.c',
   'socket.c',
   'setspeed.c',
-  'rs485.c'
+  'rs485.c',
+  'alert.c'
 ]
 
 tio_dep = dependency('inih', required: true,

src/misc.c

@@ -22,6 +22,7 @@
 #include "config.h"
 #include <stdio.h>
 #include <stdlib.h>
+#include <unistd.h>
 #include <string.h>
 #include <time.h>
 #include <sys/time.h>

src/misc.h

@@ -27,3 +27,5 @@ char * current_time(void);
 void delay(long ms);
 long string_to_long(char *string);
 int ctrl_key_code(unsigned char key);
+void alert_connect(void);
+void alert_disconnect(void);

src/options.c

@@ -36,6 +36,7 @@
 #include "print.h"
 #include "tty.h"
 #include "rs485.h"
+#include "alert.h"
 
 enum opt_t
 {
@@ -47,6 +48,7 @@ enum opt_t
     OPT_RESPONSE_TIMEOUT,
     OPT_RS485,
     OPT_RS485_CONFIG,
+    OPT_ALERT,
 };
 
 /* Default options */
@@ -85,6 +87,7 @@ struct option_t option =
     .rs485_config_flags = 0,
     .rs485_delay_rts_before_send = -1,
     .rs485_delay_rts_after_send = -1,
+    .alert = ALERT_NONE,
 };
 
 void print_help(char *argv[])
@@ -118,6 +121,7 @@ void print_help(char *argv[])
     printf("      --response-timeout <ms>            Response timeout (default: 100)\n");
     printf("      --rs-485                           Enable RS-485 mode\n");
     printf("      --rs-485-config <config>           Set RS-485 configuration\n");
+    printf("      --alert none|bell|blink            Alert on connect/disconnect (default: none)\n");
     printf("  -v, --version                          Display version\n");
     printf("  -h, --help                             Display help\n");
     printf("\n");
@@ -159,7 +163,7 @@ const char* timestamp_state_to_string(enum timestamp_t timestamp)
 enum timestamp_t timestamp_option_parse(const char *arg)
 {
     enum timestamp_t timestamp = TIMESTAMP_24HOUR; // Default
-    
+
     if (arg != NULL)
     {
         if (strcmp(arg, "24hour") == 0)
@@ -237,7 +241,6 @@ void line_pulse_duration_option_parse(const char *arg)
         }
     }
     free(buffer);
-
 }
 
 void options_print()
@@ -306,6 +309,7 @@ void options_parse(int argc, char *argv[])
             {"response-timeout",    required_argument, 0, OPT_RESPONSE_TIMEOUT   },
             {"rs-485",              no_argument,       0, OPT_RS485              },
             {"rs-485-config",       required_argument, 0, OPT_RS485_CONFIG       },
+            {"alert",               required_argument, 0, OPT_ALERT              },
             {"version",             no_argument,       0, 'v'                    },
             {"help",                no_argument,       0, 'h'                    },
             {0,                     0,                 0,  0                     }
@@ -456,6 +460,10 @@ void options_parse(int argc, char *argv[])
                 rs485_parse_config(optarg);
                 break;
 
+            case OPT_ALERT:
+                option.alert = alert_option_parse(optarg);
+                break;
+
             case 'v':
                 printf("tio v%s\n", VERSION);
                 exit(EXIT_SUCCESS);

src/options.h

@@ -26,6 +26,7 @@
 #include <limits.h>
 #include <termios.h>
 #include <sys/param.h>
+#include "alert.h"
 
 enum timestamp_t
 {
@@ -75,6 +76,7 @@ struct option_t
     uint32_t rs485_config_flags;
     int32_t rs485_delay_rts_before_send;
     int32_t rs485_delay_rts_after_send;
+    enum alert_t alert;
 };
 
 extern struct option_t option;
@@ -84,3 +86,4 @@ void options_parse(int argc, char *argv[]);
 void options_parse_final(int argc, char *argv[]);
 
 void line_pulse_duration_option_parse(const char *arg);
+enum alert_t alert_option_parse(const char *arg);

src/tty.c

@@ -51,6 +51,8 @@
 #include "socket.h"
 #include "setspeed.h"
 #include "rs485.h"
+#include "alert.h"
+#include "misc.h"
 
 #ifdef __APPLE__
 #define PATH_SERIAL_DEVICES "/dev/"
@@ -950,6 +952,9 @@ void tty_disconnect(void)
         flock(fd, LOCK_UN);
         close(fd);
         connected = false;
+
+        /* Fire alert action */
+        alert_disconnect();
     }
 }
 
@@ -1066,6 +1071,9 @@ int tty_connect(void)
     connected = true;
     print_tainted = false;
 
+    /* Fire alert action */
+    alert_connect();
+
     if (option.timestamp)
     {
         next_timestamp = true;