450 lines
12 KiB
C++
450 lines
12 KiB
C++
// ------------------------------------------------------------------------
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// audioio-forked-streams.cpp: Helper class providing routines for
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// forking for piped input/output.
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// Copyright (C) 2000-2004,2006,2008 Kai Vehmanen
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//
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// Attributes:
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// eca-style-version: 3 (see Ecasound Programmer's Guide)
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//
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// This program is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation; either version 2 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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// ------------------------------------------------------------------------
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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#include <cstdlib>
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#include <vector>
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#include <string>
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#include <cstring>
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#include <iostream>
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#include <cstring>
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#include <cstdio>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <fcntl.h>
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#include <signal.h>
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#include <unistd.h>
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#include <errno.h>
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#include <kvu_dbc.h>
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#include <kvu_numtostr.h>
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#include <kvu_utils.h>
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#include "eca-logger.h"
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#include "audioio-forked-stream.h"
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using namespace std;
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/**
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* Maximum number of arguments passed to exec()
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*/
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const static int afs_max_exec_args = 1024;
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/**
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* Runs exec() with the given parameters.
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* @return exec() return value
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*/
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static int afs_run_exec(const string& command, const string& filename)
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{
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vector<string> temp = kvu_string_to_tokens_quoted(command);
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if (static_cast<int>(temp.size()) > afs_max_exec_args) {
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temp.resize(afs_max_exec_args);
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ECA_LOG_MSG(ECA_LOGGER::info, "WARNING: too many arguments for external application, truncating.");
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}
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const char* args[afs_max_exec_args];
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vector<string>::size_type p = 0;
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while(p < temp.size()) {
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if (temp[p].find("%f") != string::npos) {
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temp[p].replace(temp[p].find("%f"), 2, filename);
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args[p] = temp[p].c_str();
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}
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else
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args[p] = temp[p].c_str();
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++p;
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}
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args[p] = 0;
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return execvp(temp[0].c_str(), const_cast<char**>(args));
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}
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AUDIO_IO_FORKED_STREAM::~AUDIO_IO_FORKED_STREAM(void)
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{
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if (pid_of_child_rep > 0)
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clean_child(true);
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}
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void AUDIO_IO_FORKED_STREAM::stop_io(void)
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{
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ECA_LOG_MSG(ECA_LOGGER::user_objects, "stop_io()");
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clean_child(false);
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}
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/**
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* If found, replaces the string '%f' with 'filename'. This is
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* the file used by the forked child for input/output.
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*/
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void AUDIO_IO_FORKED_STREAM::set_fork_file_name(const string& filename)
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{
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object_rep = filename;
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/* do not yet replace %f yet as it would make it more
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difficult to tokenize the exec string */
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}
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/**
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* If found, replaces the string '%F' with a path name to a
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* temporary named pipe. This pipe will be used for communicating
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* with the forked child instead of standard input and output pipes.
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*/
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void AUDIO_IO_FORKED_STREAM::set_fork_pipe_name(void)
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{
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if (command_rep.find("%F") != string::npos) {
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use_named_pipe_rep = true;
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init_temp_directory();
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if (tempfile_dir_rep.is_valid() == true) {
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tmpfile_repp = tempfile_dir_rep.create_filename("fork-pipe", ".raw");
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::mkfifo(tmpfile_repp.c_str(), 0755);
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command_rep.replace(command_rep.find("%F"), 2, tmpfile_repp);
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tmp_file_created_rep = true;
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}
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else
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tmp_file_created_rep = false;
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}
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else
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use_named_pipe_rep = false;
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}
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void AUDIO_IO_FORKED_STREAM::init_temp_directory(void)
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{
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string tmpdir ("ecasound-");
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char* tmp_p = getenv("USER");
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if (tmp_p != NULL) {
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tmpdir += string(tmp_p);
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tempfile_dir_rep.reserve_directory(tmpdir);
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}
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if (tempfile_dir_rep.is_valid() != true) {
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ECA_LOG_MSG(ECA_LOGGER::info, "WARNING: Unable to create temporary directory \"" + tmpdir + "\".");
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}
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}
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/**
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* If found, replaces the string '%c' with value of parameter
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* 'channels'.
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*/
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void AUDIO_IO_FORKED_STREAM::set_fork_channels(int channels)
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{
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if (command_rep.find("%c") != string::npos) {
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command_rep.replace(command_rep.find("%c"), 2, kvu_numtostr(channels));
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}
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}
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/**
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* If found, replaces the string '%s' with value of parameter
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* 'sample_rate', and '%S' with 'sample_rate/1000' (kHz).
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*/
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void AUDIO_IO_FORKED_STREAM::set_fork_sample_rate(long int sample_rate)
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{
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if (command_rep.find("%s") != string::npos) {
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command_rep.replace(command_rep.find("%s"), 2, kvu_numtostr(sample_rate));
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}
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if (command_rep.find("%S") != string::npos) {
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command_rep.replace(command_rep.find("%S"), 2, kvu_numtostr(sample_rate/1000.0f));
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}
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}
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/**
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* If found, replaces the string '%b' with value of parameter
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* 'bits'.
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*/
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void AUDIO_IO_FORKED_STREAM::set_fork_bits(int bits)
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{
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if (command_rep.find("%b") != string::npos) {
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command_rep.replace(command_rep.find("%b"), 2, kvu_numtostr(bits));
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}
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}
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void AUDIO_IO_FORKED_STREAM::fork_child_for_read(void)
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{
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ECA_LOG_MSG(ECA_LOGGER::user_objects, "Fork child-for-read: '" + fork_command() + "'");
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init_state_before_fork();
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if (use_named_pipe_rep == true) {
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if (tmp_file_created_rep == true) {
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fork_child_for_fifo_read();
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}
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else {
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last_fork_rep = false;
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}
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}
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else {
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int fpipes[2];
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if (pipe(fpipes) == 0) {
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sigkill_sent_rep = false;
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pid_of_child_rep = fork();
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if (pid_of_child_rep == 0) {
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// ---
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// child
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// ---
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sigset_t newset;
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sigemptyset(&newset);
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sigaddset(&newset, SIGTERM);
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sigaddset(&newset, SIGPIPE);
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#if defined(HAVE_PTHREAD_SIGMASK)
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pthread_sigmask(SIG_UNBLOCK, &newset, NULL);
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#elif defined(HAVE_SIGPROCMASK)
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sigprocmask(SIG_UNBLOCK, &newset, NULL);
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#endif
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::close(1);
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dup2(fpipes[1], 1);
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::close(fpipes[0]);
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::close(fpipes[1]);
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freopen("/dev/null", "w", stderr);
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int res = afs_run_exec(command_rep, object_rep);
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::close(1);
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exit(res);
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cerr << "You shouldn't see this!\n";
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}
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else if (pid_of_child_rep > 0) {
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// ---
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// parent
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// ---
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pid_of_parent_rep = ::getpid();
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::close(fpipes[1]);
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fd_rep = fpipes[0];
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if (wait_for_child() == true)
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last_fork_rep = true;
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else
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last_fork_rep = false;
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}
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}
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}
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}
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/**
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* Initializes state that needs to be reset/refresh
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* between every new fork of a child object.
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*/
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void AUDIO_IO_FORKED_STREAM::init_state_before_fork(void)
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{
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last_fork_rep = false;
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fd_rep = 0;
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if (do_supports_seeking() != true)
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do_set_position_in_samples(0);
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}
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void AUDIO_IO_FORKED_STREAM::fork_child_for_fifo_read(void)
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{
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ECA_LOG_MSG(ECA_LOGGER::user_objects, "Fork child-for-fifo-read: '" + fork_command() + "'");
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init_state_before_fork();
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sigkill_sent_rep = false;
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pid_of_child_rep = fork();
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if (pid_of_child_rep == 0) {
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// ---
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// child
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// ---
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sigset_t newset;
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sigemptyset(&newset);
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sigaddset(&newset, SIGTERM);
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sigaddset(&newset, SIGPIPE);
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#if defined(HAVE_PTHREAD_SIGMASK)
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pthread_sigmask(SIG_UNBLOCK, &newset, NULL);
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#elif defined(HAVE_SIGPROCMASK)
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sigprocmask(SIG_UNBLOCK, &newset, NULL);
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#endif
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freopen("/dev/null", "w", stderr);
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int res = afs_run_exec(command_rep, object_rep);
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if (res < 0) {
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/**
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* If execvp failed, make sure that the other end of
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* the pipe doesn't block forever.
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*/
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cerr << "execvp() failed!\n";
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int fd = open(tmpfile_repp.c_str(), O_WRONLY);
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close(fd);
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}
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exit(res);
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cerr << "You shouldn't see this!\n";
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}
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else if (pid_of_child_rep > 0) {
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// ---
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// parent
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// ---
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pid_of_parent_rep = ::getpid();
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fd_rep = 0;
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if (wait_for_child() == true)
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fd_rep = ::open(tmpfile_repp.c_str(), O_RDONLY);
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if (fd_rep > 0)
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last_fork_rep = true;
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}
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}
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void AUDIO_IO_FORKED_STREAM::fork_child_for_write(void)
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{
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ECA_LOG_MSG(ECA_LOGGER::user_objects, "Fork child-for-write: '" + fork_command() + "'");
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init_state_before_fork();
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int fpipes[2];
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if (pipe(fpipes) == 0) {
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sigkill_sent_rep = false;
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pid_of_child_rep = fork();
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if (pid_of_child_rep == 0) {
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// ---
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// child
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// ---
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sigset_t newset;
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sigaddset(&newset, SIGTERM);
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sigaddset(&newset, SIGPIPE);
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#if defined(HAVE_PTHREAD_SIGMASK)
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pthread_sigmask(SIG_UNBLOCK, &newset, NULL);
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#elif defined(HAVE_SIGPROCMASK)
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sigprocmask(SIG_UNBLOCK, &newset, NULL);
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#endif
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::close(0);
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::dup2(fpipes[0],0);
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::close(fpipes[0]);
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::close(fpipes[1]);
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freopen("/dev/null", "w", stderr);
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exit(afs_run_exec(command_rep, object_rep));
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cerr << "You shouln't see this!\n";
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}
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else if (pid_of_child_rep > 0) {
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// ---
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// parent
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// ---
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pid_of_parent_rep = ::getpid();
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::close(fpipes[0]);
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fd_rep = fpipes[1];
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if (wait_for_child() == true)
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last_fork_rep = true;
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else
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last_fork_rep = false;
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}
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}
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}
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/**
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* Cleans (waits for) the forked child process. Note! This
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* function should be called from the same thread as
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* fork_child_for_read/write() was called.
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*
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* In case the function is called from a different thread,
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* it attemts to terminate the child anyways, but the child's
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* state is not known exactly when function returns.
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*
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* @param force if true, client is terminated with SIGKILL,
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* which guarantees that it terminates (but
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* possibly without going through normal
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* exit procedure); should be avoided especially
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* for output objects as this may result in
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* data loss
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*/
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void AUDIO_IO_FORKED_STREAM::clean_child(bool force)
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{
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if (fd_rep > 0) {
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/* close the pipe between this process and the forked child
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* process, should terminate the forked application -> see
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* waitpid() below */
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::close(fd_rep);
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fd_rep = -1;
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}
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if (pid_of_child_rep > 0 &&
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force == true) {
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if (sigkill_sent_rep != true) {
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ECA_LOG_MSG(ECA_LOGGER::system_objects,
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"Sending SIGKILL to child process related to: "
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+ object_rep);
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kill(pid_of_child_rep, SIGKILL);
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sigkill_sent_rep = true;
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}
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else {
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/* SIGKILL already sent once for this process, don't send it again */
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pid_of_child_rep = -1;
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}
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}
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if (pid_of_child_rep > 0 &&
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pid_of_parent_rep == getpid()) {
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/* wait until child process has exited
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* note: this only works reliable when our pid is
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* the same as used for starting the child */
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int flags = 0;
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int status = 0;
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int res = waitpid(pid_of_child_rep, &status, flags);
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if (res == pid_of_child_rep) {
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ECA_LOG_MSG(ECA_LOGGER::system_objects, "Child process exit ok: "
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+ object_rep);
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pid_of_child_rep = 0;
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}
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else {
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ECA_LOG_MSG(ECA_LOGGER::system_objects, "Problems in terminating child process:" + std::string(strerror(errno)));
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}
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}
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if (pid_of_child_rep > 0) {
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/* wait didn't work, terminate with SIGTERM to be sure */
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ECA_LOG_MSG(ECA_LOGGER::system_objects, "Sending SIGTERM to child process: "
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+ object_rep);
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kill(pid_of_child_rep, SIGTERM);
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pid_of_child_rep = 0;
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}
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if (tmp_file_created_rep == true) {
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::remove(tmpfile_repp.c_str());
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tmp_file_created_rep = false;
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}
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}
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/**
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* Checks whether child is still active. Returns false
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* if child has exited, otherwise true.
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*/
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bool AUDIO_IO_FORKED_STREAM::wait_for_child(void) const
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{
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if (pid_of_child_rep <= 0)
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return false;
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else if (pid_of_parent_rep == getpid() &&
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pid_of_child_rep > 0) {
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int pid = waitpid(pid_of_child_rep, 0, WNOHANG);
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if (pid == pid_of_child_rep) {
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return false;
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}
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/* no change in state, so still active */
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return true;
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}
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else
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/* note: we don't really know so assume that yes */
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return true;
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}
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