jackspa-cli.c

   1 /* jackspa-cli.c - simple CLI LADSPA host for the Jack Audio Connection Kit
   2  * Copyright © 2013 Géraud Meyer <graud@gmx.com>
   3  *
   4  * This file is part of ng-jackspa.
   5  *
   6  * ng-jackspa is free software; you can redistribute it and/or modify it under
   7  * the terms of the GNU General Public License version 2 as published by the
   8  * Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with ng-jackspa.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include <stdlib.h>
  20 #include <stdio.h>
  21 #include <unistd.h>
  22 #include <signal.h>
  23 #include <fcntl.h>
  24 #include "jackspa.h"
  25 #include "control.h"
  26
  27 #define PROGRAM_NAME "jackspa-cli"
  28 #include "interface.c"
  29
  30 #define NOTIF_BACKGROUND "continuing to run in the background"
  31
  32 volatile sig_atomic_t stop_signaled = 0;
  33
  34 static void stop_handler(int s)
  35 {
  36         stop_signaled = 1;
  37 }
  38
  39 static int tty = -1; /* controlling terminal or -1 */
  40
  41 static void background_handler(int s)
  42 {
  43         int i;
  44
  45         /* setup a child that will stop us then wake us up */
  46         i = fork();
  47         if (i < 0) {
  48                 /* error, use the default handler */
  49                 signal(SIGTSTP, SIG_DFL);
  50                 kill(0, SIGTSTP);
  51         }
  52         else if (i == 0) {
  53                 if (tty >= 0 && verbose)
  54                         write( STDOUT_FILENO, PROGRAM_NAME ": " NOTIF_BACKGROUND "\n",
  55                           sizeof(PROGRAM_NAME)-1 + 2 + sizeof(NOTIF_BACKGROUND)-1 + 1 );
  56                 /* make sure the parent is not in the foreground (or has no ctty) */
  57                 for (i = 1; tcgetpgrp(tty) == getpgid(getppid()); i <<= 1) {
  58                         kill(getppid(), SIGSTOP); /* let the shell regain control of the tty */
  59                         usleep(i), kill(getppid(), SIGCONT);
  60                 }
  61                 _exit(0);
  62     }
  63 }
  64
  65 int main(int argc, char *argv[])
  66 {
  67         int rc = 0;
  68
  69         tty = open("/dev/tty", O_NOCTTY);
  70
  71         /* Signals */
  72         struct sigaction act;
  73         act.sa_flags = 0;
  74         rc = !sigemptyset(&act.sa_mask);
  75         if (rc) {
  76                 /* SIGINT handler to exit gracefully */
  77                 act.sa_handler = stop_handler;
  78                 rc = !sigaction(SIGINT, &act, NULL) && rc;
  79                 /* SIGTTIN handler to avoid being stopped */
  80                 act.sa_handler = SIG_IGN;
  81                 rc = !sigaction(SIGTTIN, &act, NULL) && rc;
  82                 /* SIGTSTP handler to go into the background */
  83                 act.sa_handler = background_handler;
  84                 rc = !sigaction(SIGTSTP, &act, NULL) && rc;
  85                 /* SIGCHLD handler to avoid a child to become defunct */
  86                 act.sa_handler = SIG_IGN;
  87                 rc = !sigaction(SIGCHLD, &act, NULL) && rc;
  88         }
  89         if (!rc)
  90                 fputs(PROGRAM_NAME ": error while setting up the signal handlers\n", stderr);
  91
  92         /* Command line options */
  93         GOptionContext *context = interface_context();
  94         GError *error = NULL;
  95         if (!g_option_context_parse(context, &argc, &argv, &error))
  96                 return (fprintf(stderr, "option parsing failed: %s\n", error->message), -1);
  97
  98         /* Initialize jackspa */
  99         state_t state;
 100         if (!jackspa_init(&state, argc, argv))
 101                 return 1;
 102
 103         /* Set the default values */
 104         unsigned long c;
 105         controls_t controls;
 106         if (control_buildall(&c, &controls, &state))
 107                 return 2;
 108
 109         /* Wait */
 110         if (!isatty(fileno(stdin)))
 111                 while (!stop_signaled) sleep(-1);
 112         else
 113                 while (!stop_signaled && !feof(stdin))
 114                         if (getpgrp() == tcgetpgrp(STDIN_FILENO))
 115                                 /* we are in the foreground process group */
 116                                 getchar();
 117                         else usleep(100000);
 118
 119         control_cleanupall(c, &controls);
 120
 121         return 0;
 122 }