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 volatile sig_atomic_t print_signaled = 0;
  66
  67 static void printcontrols_handler(int s)
  68 {
  69         print_signaled = 1;
  70 }
  71
  72 void printcontrols_async(unsigned long c, controls_t controls)
  73 {
  74         if (!print_signaled) return;
  75
  76         for (; c; c--, controls++)
  77                 printf("%e\t# %s\n", *(*controls)->val, (*controls)->name);
  78         print_signaled = 0;
  79 }
  80
  81 int main(int argc, char *argv[])
  82 {
  83         int rc = 0;
  84
  85         tty = open("/dev/tty", O_NOCTTY);
  86
  87         /* Signals */
  88         struct sigaction act;
  89         act.sa_flags = 0;
  90         rc = !sigemptyset(&act.sa_mask);
  91         if (rc) {
  92                 /* SIGINT handler to exit gracefully */
  93                 act.sa_handler = stop_handler;
  94                 rc = !sigaction(SIGINT, &act, NULL) && rc;
  95                 /* SIGTTIN handler to avoid being stopped */
  96                 act.sa_handler = SIG_IGN;
  97                 rc = !sigaction(SIGTTIN, &act, NULL) && rc;
  98                 /* SIGTSTP handler to go into the background */
  99                 act.sa_handler = background_handler;
 100                 rc = !sigaction(SIGTSTP, &act, NULL) && rc;
 101                 /* SIGCHLD handler to avoid a child to become defunct */
 102                 act.sa_handler = SIG_IGN;
 103                 rc = !sigaction(SIGCHLD, &act, NULL) && rc;
 104                 /* SIGUSR1 to print the active values */
 105                 act.sa_handler = printcontrols_handler;
 106                 rc = !sigaction(SIGUSR1, &act, NULL) && rc;
 107         }
 108         if (!rc)
 109                 fputs(PROGRAM_NAME ": error while setting up the signal handlers\n", stderr);
 110
 111         /* Command line options */
 112         GOptionContext *context = interface_context();
 113         GError *error = NULL;
 114         if (!g_option_context_parse(context, &argc, &argv, &error))
 115                 return (fprintf(stderr, "option parsing failed: %s\n", error->message), -1);
 116
 117         /* Initialize jackspa */
 118         state_t state;
 119         if (!jackspa_init(&state, argc, argv))
 120                 return 1;
 121
 122         /* Initialize the controls with the requested values */
 123         unsigned long c;
 124         controls_t controls;
 125         if (control_buildall(&c, &controls, &state))
 126                 return 2;
 127
 128         /* Wait */
 129         if (!isatty(fileno(stdin)))
 130                 while (!stop_signaled) {
 131                         printcontrols_async(c, controls);
 132                         sleep(-1);
 133                 }
 134         else
 135                 while (!stop_signaled && !feof(stdin)) {
 136                         printcontrols_async(c, controls);
 137                         if (getpgrp() == tcgetpgrp(STDIN_FILENO))
 138                                 /* we are in the foreground process group */
 139                                 getchar();
 140                         else usleep(100000);
 141                 }
 142
 143         control_cleanupall(c, &controls);
 144         jackspa_fini(&state);
 145
 146         return 0;
 147 }