+/*
+ * This file is part of DisOrder.
+ * Copyright (C) 2005, 2006, 2007, 2009 Richard Kettlewell
+ * Portions (C) 2007 Mark Wooding
+ *
+ * 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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+/** @file lib/uaudio-command.c
+ * @brief Support for commmand backend */
+#include "common.h"
+
+#include <errno.h>
+#include <unistd.h>
+
+#include "syscalls.h"
+#include "log.h"
+#include "mem.h"
+#include "wstat.h"
+#include "uaudio.h"
+
+/** @brief Pipe to subprocess */
+static int command_fd;
+
+/** @brief Child process ID */
+static pid_t command_pid;
+
+static const char *const command_options[] = {
+ "command",
+ NULL
+};
+
+/** @brief Close pipe and wait for subprocess to terminate */
+static void command_wait(void) {
+ int w;
+ pid_t rc;
+ char *ws;
+
+ close(command_fd);
+ while((rc = waitpid(command_pid, &w, 0) < 0 && errno == EINTR))
+ ;
+ if(rc < 0)
+ fatal(errno, "waitpid");
+ if(w) {
+ ws = wstat(w);
+ error(0, "command subprocess %s", ws);
+ xfree(ws);
+ }
+}
+
+/** @brief Create subprocess */
+static void command_open(void) {
+ int pfd[2];
+ const char *command;
+
+ if(!(command = uaudio_get("command")))
+ fatal(0, "'command' not set");
+ xpipe(pfd);
+ command_pid = xfork();
+ if(!command_pid) {
+ exitfn = _exit;
+ signal(SIGPIPE, SIG_DFL);
+ xdup2(pfd[0], 0);
+ close(pfd[0]);
+ close(pfd[1]);
+ /* TODO it would be nice to set some environment variables given the sample
+ * format. The original intended model is that you adapt DisOrder to the
+ * command you run but it'd be nice to support the opposite. */
+ execl("/bin/sh", "sh", "-c", command, (char *)0);
+ fatal(errno, "error executing /bin/sh");
+ }
+ close(pfd[0]);
+ command_pid = pfd[1];
+}
+
+/** @brief Send audio data to subprocess */
+static size_t command_play(void *buffer, size_t nsamples) {
+ const size_t bytes = nsamples * uaudio_sample_size;
+ int written = write(command_fd, buffer, bytes);
+ if(written < 0) {
+ switch(errno) {
+ case EINTR:
+ return 0; /* will retry */
+ case EPIPE:
+ error(0, "audio command subprocess terminated");
+ command_wait();
+ command_open();
+ return 0; /* will retry */
+ default:
+ fatal(errno, "error writing to audio command subprocess");
+ }
+ }
+ return written / uaudio_sample_size;
+}
+
+static void command_start(uaudio_callback *callback,
+ void *userdata) {
+ command_open();
+ uaudio_thread_start(callback,
+ userdata,
+ command_play,
+ uaudio_channels,
+ 4096 / uaudio_sample_size);
+}
+
+static void command_stop(void) {
+ uaudio_thread_stop();
+ command_wait();
+}
+
+static void command_activate(void) {
+ uaudio_thread_activate();
+}
+
+static void command_deactivate(void) {
+ uaudio_thread_deactivate();
+}
+
+const struct uaudio uaudio_command = {
+ .name = "command",
+ .options = command_options,
+ .start = command_start,
+ .stop = command_stop,
+ .activate = command_activate,
+ .deactivate = command_deactivate
+};
+
+/*
+Local Variables:
+c-basic-offset:2
+comment-column:40
+fill-column:79
+indent-tabs-mode:nil
+End:
+*/
~mdw / disorder / commitdiff