From a7c3a5c479812f1f69acac276402fdffc60371aa Mon Sep 17 00:00:00 2001
From: Christian Pointner <equinox@spreadspace.org>
Date: Wed, 3 Sep 2014 23:09:49 +0200
Subject: added initial code - based on rharchive

---
 src/Makefile      | 110 +++++++++++++++++
 src/configure     | 167 +++++++++++++++++++++++++
 src/daemon.h      | 168 +++++++++++++++++++++++++
 src/datatypes.h   |  41 +++++++
 src/file_list.c   | 222 +++++++++++++++++++++++++++++++++
 src/file_list.h   |  67 ++++++++++
 src/log.c         | 265 ++++++++++++++++++++++++++++++++++++++++
 src/log.h         |  87 +++++++++++++
 src/log_targets.h | 357 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/options.c     | 337 +++++++++++++++++++++++++++++++++++++++++++++++++++
 src/options.h     |  67 ++++++++++
 src/sig_handler.c | 113 +++++++++++++++++
 src/sig_handler.h |  39 ++++++
 src/slist.c       | 132 ++++++++++++++++++++
 src/slist.h       |  53 ++++++++
 src/string_list.c |  71 +++++++++++
 src/string_list.h |  43 +++++++
 src/sydra.c       | 255 ++++++++++++++++++++++++++++++++++++++
 src/sysexec.c     | 226 ++++++++++++++++++++++++++++++++++
 src/sysexec.h     |  51 ++++++++
 src/writer.c      | 243 +++++++++++++++++++++++++++++++++++++
 src/writer.h      |  64 ++++++++++
 22 files changed, 3178 insertions(+)
 create mode 100644 src/Makefile
 create mode 100755 src/configure
 create mode 100644 src/daemon.h
 create mode 100644 src/datatypes.h
 create mode 100644 src/file_list.c
 create mode 100644 src/file_list.h
 create mode 100644 src/log.c
 create mode 100644 src/log.h
 create mode 100644 src/log_targets.h
 create mode 100644 src/options.c
 create mode 100644 src/options.h
 create mode 100644 src/sig_handler.c
 create mode 100644 src/sig_handler.h
 create mode 100644 src/slist.c
 create mode 100644 src/slist.h
 create mode 100644 src/string_list.c
 create mode 100644 src/string_list.h
 create mode 100644 src/sydra.c
 create mode 100644 src/sysexec.c
 create mode 100644 src/sysexec.h
 create mode 100644 src/writer.c
 create mode 100644 src/writer.h

(limited to 'src')

diff --git a/src/Makefile b/src/Makefile
new file mode 100644
index 0000000..456b20a
--- /dev/null
+++ b/src/Makefile
@@ -0,0 +1,110 @@
+##
+##  sydra
+##
+##  sydra is a toolbox which allows you to set up multiple bidirectional
+##  Video/Audio streams from external locations.
+##  sydra has been written to be used for the Elevate Festival in Graz
+##  Austria in order to involve external locations to present themselves
+##  at the festival.
+##  Sydra is based on GStreamer and is written in C.
+##
+##
+##  Copyright (C) 2014 Christian Pointner <equinox@helsinki.at>
+##
+##  This file is part of sydra.
+##
+##  sydra 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
+##  any later version.
+##
+##  sydra 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 sydra. If not, see <http://www.gnu.org/licenses/>.
+##
+
+ifneq ($(MAKECMDGOALS),distclean)
+include include.mk
+endif
+
+EXECUTABLE := sydra
+
+C_OBJS := log.o \
+          sig_handler.o \
+          options.o \
+          slist.o \
+          string_list.o \
+          sysexec.o \
+          file_list.o \
+          writer.o \
+          sydra.o
+
+C_SRCS := $(C_OBJS:%.o=%.c)
+
+.PHONY: clean cleanall distclean manpage install install-bin uninstall remove
+
+all: $(EXECUTABLE)
+
+%.d: %.c
+	@set -e; rm -f $@; \
+  $(CC) -MM $(CFLAGS) $< > $@.$$$$; \
+  sed 's,\($*\)\.o[ :]*,\1.o $@ : ,g' < $@.$$$$ > $@; \
+  rm -f $@.$$$$; echo '(re)building $@'
+
+ifneq ($(MAKECMDGOALS),distclean)
+-include $(C_SRCS:%.c=%.d)
+endif
+
+$(EXECUTABLE): $(C_OBJS)
+	$(CC) $(C_OBJS) -o $@ $(LDFLAGS)
+
+%.o: %.c
+	$(CC) $(CFLAGS) -c $<
+
+strip: $(EXECUTABLE)
+	$(STRIP) -s $(EXECUTABLE)
+
+
+distclean: clean
+	find . -name *.o -exec rm -f {} \;
+	find . -name "*.\~*" -exec rm -rf {} \;
+	rm -f include.mk
+	rm -f config.h
+
+clean:
+	rm -f *.o
+	rm -f *.d
+	rm -f *.d.*
+	rm -f $(EXECUTABLE)
+
+INSTALL_TARGETS := install-bin
+REMOVE_TARGETS := remove-bin
+
+ifdef MANDIR
+INSTALL_TARGETS += install-man
+REMOVE_TARGETS += remove-man
+endif
+
+install: all $(INSTALL_TARGETS)
+
+install-bin: $(EXECUTABLE)
+	$(INSTALL) -d $(DESTDIR)$(BINDIR)
+	$(INSTALL) -m 755 $(EXECUTABLE) $(DESTDIR)$(BINDIR)
+
+install-man: manpage
+	$(INSTALL) -d $(DESTDIR)$(MANDIR)/man8/
+	$(INSTALL) -m 644 ../doc/$(EXECUTABLE).8 $(DESTDIR)$(MANDIR)/man8/$(EXECUTABLE).8
+
+uninstall: remove
+
+remove: $(REMOVE_TARGETS)
+
+remove-bin:
+	rm -f $(DESTDIR)$(BINDIR)/$(EXECUTABLE)
+
+remove-man:
+	rm -f $(DESTDIR)$(MANDIR)/man8/$(EXECUTABLE).8
diff --git a/src/configure b/src/configure
new file mode 100755
index 0000000..f7ddc99
--- /dev/null
+++ b/src/configure
@@ -0,0 +1,167 @@
+#!/bin/sh
+#
+#   sydra
+#
+#   sydra is a toolbox which allows you to set up multiple bidirectional
+#   Video/Audio streams from external locations.
+#   sydra has been written to be used for the Elevate Festival in Graz
+#   Austria in order to involve external locations to present themselves
+#   at the festival.
+#   Sydra is based on GStreamer and is written in C.
+#
+#
+#   Copyright (C) 2014 Christian Pointner <equinox@helsinki.at>
+#
+#   This file is part of sydra.
+#
+#   sydra 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
+#   any later version.
+#
+#   sydra 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 sydra. If not, see <http://www.gnu.org/licenses/>.
+#
+
+set -e
+
+TARGET=`uname -s`
+EBUILD_COMPAT=0
+USE_CLANG=0
+
+PREFIX='/usr/local'
+BINDIR=''
+
+print_usage() {
+  echo "configure --help                    print this"
+  echo "          --target=<TARGET>         build target i.e. Linux (default: autodetect)"
+  echo "          --prefix=<PREFIX>         the installation prefix (default: /usr/local)"
+  echo "          --bindir=<DIR>            the path to the bin directory (default: $PREFIX/bin)"
+  echo "          --use-clang               use clang/llvm as compiler/linker"
+}
+
+for arg
+do
+  case $arg in
+  --target=*)
+    TARGET=${arg#--target=}
+  ;;
+  --prefix=*)
+    PREFIX=${arg#--prefix=}
+  ;;
+  --bindir=*)
+    BINDIR=${arg#--bindir=}
+  ;;
+  --use-clang)
+    USE_CLANG=1
+  ;;
+  --ebuild-compat)
+    EBUILD_COMPAT=1
+  ;;
+  --help)
+    print_usage
+    exit 0
+  ;;
+  *)
+    ERRORS="$ERRORS $arg"
+  ;;
+  esac
+done
+
+if [ -n "$ERRORS" ] && [ $EBUILD_COMPAT -ne 1 ]; then
+  for error in $ERRORS; do
+    echo "Unknown argument: $error"
+  done
+
+  print_usage
+  exit 1
+fi
+
+if [ $USE_CLANG -eq 0 ]; then
+  CFLAGS='-g -Wall -O2'
+  LDFLAGS='-g -Wall -O2'
+  COMPILER='gcc'
+else
+  CFLAGS='-g -O2'
+  LDFLAGS='-g -O2'
+  COMPILER='clang'
+fi
+
+CFLAGS="$CFLAGS $(pkg-config --cflags gstreamer-0.10) -DGST_DISABLE_DEPRECATED"
+LDFLAGS="$LDFLAGS $(pkg-config --libs gstreamer-0.10)"
+
+rm -f include.mk
+rm -f config.h
+case $TARGET in
+  Linux)
+  ;;
+  OpenBSD|FreeBSD|NetBSD|GNU/kFreeBSD)
+    CFLAGS=$CFLAGS' -I/usr/local/include'
+    LDFLAGS=$LDFLAGS' -L/usr/local/lib'
+  ;;
+  *)
+    echo "platform not supported"
+    exit 1;
+  ;;
+esac
+
+if [ -z "$BINDIR" ]; then
+  BINDIR=$PREFIX/bin
+fi
+
+cat > include.mk <<EOF
+# this file was created automatically
+# do not edit this file directly
+# use ./configure instead
+
+TARGET := '$TARGET'
+CC := $COMPILER
+CFLAGS := $CFLAGS
+LDFLAGS := $LDFLAGS
+STRIP := strip
+INSTALL := install
+RAGEL := ragel
+
+PREFIX := '$PREFIX'
+BINDIR := '$BINDIR'
+EOF
+
+VERSION=`cat ../version`
+if which git >/dev/null; then
+    GIT_HASH=`git rev-parse HEAD 2> /dev/null`
+    if [ -n "$GIT_HASH" ]; then
+        VERSION="$VERSION (git $GIT_HASH)"
+    fi
+fi
+
+HOSTNAME=`hostname`
+DATE=`date +"%d.%m.%Y %H:%M:%S %Z"`
+
+cat > config.h <<EOF
+/*
+ * sydra config header
+ *
+ * this file was created automatically
+ * do not edit this file directly
+ * use ./configure instead
+ */
+
+#ifndef SYDRA_config_h_INCLUDED
+#define SYDRA_config_h_INCLUDED
+
+#define VERSION_STRING_0 "sydra version $VERSION"
+#define VERSION_STRING_1 "built on $HOSTNAME, $DATE"
+
+#define TARGET "$TARGET"
+#define PREFIX "$PREFIX"
+#define BINDIR "$BINDIR"
+
+#endif
+EOF
+
+exit 0
diff --git a/src/daemon.h b/src/daemon.h
new file mode 100644
index 0000000..b7c2880
--- /dev/null
+++ b/src/daemon.h
@@ -0,0 +1,168 @@
+/*
+ *  sydra
+ *
+ *  sydra is a toolbox which allows you to set up multiple bidirectional
+ *  Video/Audio streams from external locations.
+ *  sydra has been written to be used for the Elevate Festival in Graz
+ *  Austria in order to involve external locations to present themselves
+ *  at the festival.
+ *  Sydra is based on GStreamer and is written in C.
+ *
+ *
+ *  Copyright (C) 2014 Christian Pointner <equinox@helsinki.at>
+ *
+ *  This file is part of sydra.
+ *
+ *  sydra 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
+ *  any later version.
+ *
+ *  sydra 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 sydra. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef SYDRA_daemon_h_INCLUDED
+#define SYDRA_daemon_h_INCLUDED
+
+#include <poll.h>
+#include <fcntl.h>
+#include <pwd.h>
+#include <grp.h>
+#include <sys/wait.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+struct priv_info_struct {
+  struct passwd* pw_;
+  struct group* gr_;
+};
+typedef struct priv_info_struct priv_info_t;
+
+int priv_init(priv_info_t* priv, const char* username, const char* groupname)
+{
+  if(!priv)
+    return -1;
+
+  priv->pw_ = NULL;
+  priv->gr_ = NULL;
+
+  priv->pw_ = getpwnam(username);
+  if(!priv->pw_) {
+    log_printf(ERROR, "unknown user %s", username);
+    return -1;
+  }
+
+  if(groupname)
+    priv->gr_ = getgrnam(groupname);
+  else
+    priv->gr_ = getgrgid(priv->pw_->pw_gid);
+
+  if(!priv->gr_) {
+    log_printf(ERROR, "unknown group %s", groupname);
+    return -1;
+  }
+
+  return 0;
+}
+
+int priv_drop(priv_info_t* priv)
+{
+  if(!priv || !priv->pw_ || !priv->gr_) {
+    log_printf(ERROR, "privileges not initialized properly");
+    return -1;
+  }
+
+  if(setgid(priv->gr_->gr_gid))  {
+    log_printf(ERROR, "setgid('%s') failed: %s", priv->gr_->gr_name, strerror(errno));
+    return -1;
+  }
+
+  gid_t gr_list[1];
+  gr_list[0] = priv->gr_->gr_gid;
+  if(setgroups (1, gr_list)) {
+    log_printf(ERROR, "setgroups(['%s']) failed: %s", priv->gr_->gr_name, strerror(errno));
+    return -1;
+  }
+
+  if(setuid(priv->pw_->pw_uid)) {
+    log_printf(ERROR, "setuid('%s') failed: %s", priv->pw_->pw_name, strerror(errno));
+    return -1;
+  }
+
+  log_printf(NOTICE, "dropped privileges to %s:%s", priv->pw_->pw_name, priv->gr_->gr_name);
+  return 0;
+}
+
+
+int do_chroot(const char* chrootdir)
+{
+  if(getuid() != 0) {
+    log_printf(ERROR, "this program has to be run as root in order to run in a chroot");
+    return -1;
+  }
+
+  if(chroot(chrootdir)) {
+    log_printf(ERROR, "can't chroot to %s: %s", chrootdir, strerror(errno));
+    return -1;
+  }
+  log_printf(NOTICE, "we are in chroot jail (%s) now", chrootdir);
+  if(chdir("/")) {
+    log_printf(ERROR, "can't change to /: %s", strerror(errno));
+    return -1;
+  }
+
+  return 0;
+}
+
+void daemonize()
+{
+  pid_t pid;
+
+  pid = fork();
+  if(pid < 0) {
+    log_printf(ERROR, "daemonizing failed at fork(): %s, exitting", strerror(errno));
+    exit(-1);
+  }
+  if(pid) exit(0);
+
+  umask(0);
+
+  if(setsid() < 0) {
+    log_printf(ERROR, "daemonizing failed at setsid(): %s, exitting", strerror(errno));
+    exit(-1);
+  }
+
+  pid = fork();
+  if(pid < 0) {
+    log_printf(ERROR, "daemonizing failed at fork(): %s, exitting", strerror(errno));
+    exit(-1);
+  }
+  if(pid) exit(0);
+
+  if ((chdir("/")) < 0) {
+    log_printf(ERROR, "daemonizing failed at chdir(): %s, exitting", strerror(errno));
+    exit(-1);
+  }
+
+  int fd;
+  for (fd=0;fd<=2;fd++) // close all file descriptors
+    close(fd);
+  fd = open("/dev/null",O_RDWR);        // stdin
+  if(fd == -1)
+    log_printf(WARNING, "can't open stdin (chroot and no link to /dev/null?)");
+  else {
+    if(dup(fd) == -1)   // stdout
+      log_printf(WARNING, "can't open stdout");
+    if(dup(fd) == -1)   // stderr
+      log_printf(WARNING, "can't open stderr");
+  }
+  umask(027);
+}
+
+#endif
diff --git a/src/datatypes.h b/src/datatypes.h
new file mode 100644
index 0000000..365ed99
--- /dev/null
+++ b/src/datatypes.h
@@ -0,0 +1,41 @@
+/*
+ *  sydra
+ *
+ *  sydra is a toolbox which allows you to set up multiple bidirectional
+ *  Video/Audio streams from external locations.
+ *  sydra has been written to be used for the Elevate Festival in Graz
+ *  Austria in order to involve external locations to present themselves
+ *  at the festival.
+ *  Sydra is based on GStreamer and is written in C.
+ *
+ *
+ *  Copyright (C) 2014 Christian Pointner <equinox@helsinki.at>
+ *
+ *  This file is part of sydra.
+ *
+ *  sydra 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
+ *  any later version.
+ *
+ *  sydra 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 sydra. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef SYDRA_datatypes_h_INCLUDED
+#define SYDRA_datatypes_h_INCLUDED
+
+#include <stdint.h>
+
+struct buffer_struct {
+  uint32_t length_;
+  uint8_t* buf_;
+};
+typedef struct buffer_struct buffer_t;
+
+#endif
diff --git a/src/file_list.c b/src/file_list.c
new file mode 100644
index 0000000..92296f0
--- /dev/null
+++ b/src/file_list.c
@@ -0,0 +1,222 @@
+/*
+ *  sydra
+ *
+ *  sydra is a toolbox which allows you to set up multiple bidirectional
+ *  Video/Audio streams from external locations.
+ *  sydra has been written to be used for the Elevate Festival in Graz
+ *  Austria in order to involve external locations to present themselves
+ *  at the festival.
+ *  Sydra is based on GStreamer and is written in C.
+ *
+ *
+ *  Copyright (C) 2014 Christian Pointner <equinox@helsinki.at>
+ *
+ *  This file is part of sydra.
+ *
+ *  sydra 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
+ *  any later version.
+ *
+ *  sydra 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 sydra. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#define _GNU_SOURCE
+#include <unistd.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <time.h>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
+
+#include <glib.h>
+
+#include "datatypes.h"
+#include "file_list.h"
+#include "slist.h"
+#include "log.h"
+
+static void delete_file(void* element)
+{
+  file_t* deletee = (file_t*)element;
+  log_printf(INFO, "removing/closing file '%s' -> %d", deletee->path_, deletee->fd_);
+  if(deletee->path_) free(deletee->path_);
+  if(deletee->fd_ >= 0) close(deletee->fd_);
+  if(deletee->pp_child_) free_child(deletee->pp_child_);
+}
+
+int file_list_init(file_list_t* list)
+{
+  g_mutex_init(&(list->mutex_));
+  return slist_init(&(list->list_), &delete_file);
+}
+
+void file_list_clear(file_list_t* list)
+{
+  g_mutex_lock(&(list->mutex_));
+  slist_clear(&(list->list_));
+  g_mutex_unlock(&(list->mutex_));
+}
+
+file_t* file_list_add(file_list_t* list, struct tm* time, const char* type, const char* format, const char* dir, mode_t mode, int nocache)
+{
+  if(!list || !(&(list->mutex_)))
+    return NULL;
+
+  file_t* tmp = malloc(sizeof(file_t));
+  if(!tmp)
+    return NULL;
+
+  log_printf(INFO, "%s time: %02d:%02d:%02d on %d.%d.%d%s", type, time->tm_hour, time->tm_min, time->tm_sec, time->tm_mday, time->tm_mon+1, time->tm_year+1900, time->tm_isdst > 0 ? " (DST)": "");
+
+  char name[256];
+  strftime(name, sizeof(name), format, time);
+  int len = asprintf(&(tmp->path_), "%s/%s", dir, name);
+  if(len == -1) {
+    free(tmp);
+    return NULL;
+  }
+
+  log_printf(INFO, "%s filename is: %s(.?)", type, tmp->path_);
+  tmp->fd_ = FILE_CLOSED;
+  tmp->mode_ = mode;
+  tmp->nocache_ = nocache;
+  tmp->pp_child_ = NULL;
+
+  g_mutex_lock(&(list->mutex_));
+  if(slist_add(&(list->list_), tmp) == NULL) {
+    g_mutex_unlock(&(list->mutex_));
+    free(tmp->path_);
+    free(tmp);
+    return NULL;
+  }
+  g_mutex_unlock(&(list->mutex_));
+
+  return tmp;
+}
+
+int file_list_remove(file_list_t* list, int fd)
+{
+  if(!list || !(&(list->mutex_)))
+    return -1;
+
+  g_mutex_lock(&(list->mutex_));
+  slist_element_t* tmp = list->list_.first_;
+  while(tmp) {
+    if(((file_t*)tmp->data_)->fd_ == fd) {
+      slist_remove(&(list->list_), tmp->data_);
+      break;
+    }
+    tmp = tmp->next_;
+  }
+  g_mutex_unlock(&(list->mutex_));
+
+  return 0;
+}
+
+int file_list_call_post_process(file_list_t* list, int fd, char* script)
+{
+  if(!list || !(&(list->mutex_)))
+    return -1;
+
+  g_mutex_lock(&(list->mutex_));
+  slist_element_t* tmp = list->list_.first_;
+  while(tmp) {
+    if(((file_t*)tmp->data_)->fd_ == fd) {
+      log_printf(INFO, "calling post processing for '%s'", ((file_t*)tmp->data_)->path_);
+      close(((file_t*)tmp->data_)->fd_);
+      ((file_t*)tmp->data_)->fd_ = FILE_POST_PROCESS;
+
+      char* const argv[] = { script, ((file_t*)tmp->data_)->path_, NULL };
+      char* const evp[] = { NULL };
+      ((file_t*)tmp->data_)->pp_child_ = sydra_exec(script, argv, evp);
+      if(!((file_t*)tmp->data_)->pp_child_)
+        slist_remove(&(list->list_), tmp->data_);
+
+      break;
+    }
+    tmp = tmp->next_;
+  }
+  g_mutex_unlock(&(list->mutex_));
+
+  return 0;
+}
+
+int file_list_waitpid(file_list_t* list)
+{
+  if(!list || !(&(list->mutex_)))
+    return -1;
+
+  g_mutex_lock(&(list->mutex_));
+  slist_element_t* tmp = list->list_.first_;
+  while(tmp) {
+    if(((file_t*)tmp->data_)->fd_ == FILE_POST_PROCESS) {
+      int ret = sydra_waitpid(((file_t*)tmp->data_)->pp_child_, NULL);
+      file_t* deletee = tmp->data_;
+      tmp = tmp->next_;
+      if(ret)
+        slist_remove(&(list->list_), deletee);
+    }
+    else
+      tmp = tmp->next_;
+  }
+  g_mutex_unlock(&(list->mutex_));
+
+  return 0;
+}
+
+int open_file(file_t* file)
+{
+  if(!file || file->fd_ != FILE_CLOSED) // file already open!
+    return -1;
+
+  char* orig_path = file->path_;
+  int cnt = 0;
+  do {
+    int flags = O_WRONLY | O_CREAT | O_EXCL;
+    if(file->nocache_)
+      flags |= O_DIRECT;
+    file->fd_ = open(file->path_, flags, file->mode_);
+    if(file->fd_ < 0) {
+      if(errno != EEXIST) {
+            // TODO: thread safe strerror
+        log_printf(ERROR, "can't open file '%s': %s", file->path_, strerror(errno));
+        if(orig_path != file->path_)
+          free(orig_path);
+        file->fd_ = FILE_CLOSED;
+        return -1;
+      }
+      cnt++;
+      char* tmp;
+      int len = asprintf(&tmp, "%s.%d", orig_path, cnt);
+      if(len == -1) {
+        if(orig_path != file->path_)
+          free(orig_path);
+        return -2;
+      }
+
+      if(file->path_ != orig_path)
+        free(file->path_);
+      file->path_ = tmp;
+    }
+    fchmod(file->fd_, file->mode_);
+  }
+  while(file->fd_ < 0);
+
+  if(orig_path != file->path_)
+    free(orig_path);
+
+  log_printf(INFO, "opened file '%s' -> %d", file->path_, file->fd_);
+
+  return 0;
+}
diff --git a/src/file_list.h b/src/file_list.h
new file mode 100644
index 0000000..6d8344c
--- /dev/null
+++ b/src/file_list.h
@@ -0,0 +1,67 @@
+/*
+ *  sydra
+ *
+ *  sydra is a toolbox which allows you to set up multiple bidirectional
+ *  Video/Audio streams from external locations.
+ *  sydra has been written to be used for the Elevate Festival in Graz
+ *  Austria in order to involve external locations to present themselves
+ *  at the festival.
+ *  Sydra is based on GStreamer and is written in C.
+ *
+ *
+ *  Copyright (C) 2014 Christian Pointner <equinox@helsinki.at>
+ *
+ *  This file is part of sydra.
+ *
+ *  sydra 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
+ *  any later version.
+ *
+ *  sydra 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 sydra. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef SYDRA_file_list_h_INCLUDED
+#define SYDRA_file_list_h_INCLUDED
+
+#include <sys/types.h>
+#include <time.h>
+
+#include <glib.h>
+
+#include "slist.h"
+#include "sysexec.h"
+
+#define FILE_CLOSED -1
+#define FILE_POST_PROCESS -2
+
+struct file_struct {
+  int fd_;
+  char* path_;
+  mode_t mode_;
+  int nocache_;
+  child_t* pp_child_;
+};
+typedef struct file_struct file_t;
+
+struct file_list_struct {
+  slist_t list_;
+  GMutex mutex_;
+};
+typedef struct file_list_struct file_list_t;
+
+int file_list_init(file_list_t* list);
+void file_list_clear(file_list_t* list);
+file_t* file_list_add(file_list_t* list, struct tm* time, const char* type, const char* format, const char* dir, mode_t mode, int nocache);
+int file_list_remove(file_list_t* list, int fd);
+int file_list_call_post_process(file_list_t* list, int fd, char* script);
+int file_list_waitpid(file_list_t* list);
+int open_file(file_t* file);
+
+#endif
diff --git a/src/log.c b/src/log.c
new file mode 100644
index 0000000..7b66553
--- /dev/null
+++ b/src/log.c
@@ -0,0 +1,265 @@
+/*
+ *  sydra
+ *
+ *  sydra is a toolbox which allows you to set up multiple bidirectional
+ *  Video/Audio streams from external locations.
+ *  sydra has been written to be used for the Elevate Festival in Graz
+ *  Austria in order to involve external locations to present themselves
+ *  at the festival.
+ *  Sydra is based on GStreamer and is written in C.
+ *
+ *
+ *  Copyright (C) 2014 Christian Pointner <equinox@helsinki.at>
+ *
+ *  This file is part of sydra.
+ *
+ *  sydra 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
+ *  any later version.
+ *
+ *  sydra 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 sydra. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "datatypes.h"
+
+#include <ctype.h>
+#include <string.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include <glib.h>
+
+#define SYSLOG_NAMES
+#include <syslog.h>
+
+#include "log.h"
+
+log_t stdlog;
+
+#include "log_targets.h"
+
+const char* log_prio_to_string(log_prio_t prio)
+{
+  switch(prio) {
+  case ERROR: return "ERROR";
+  case WARNING: return "WARNING";
+  case NOTICE: return "NOTICE";
+  case INFO: return "INFO";
+  case DEBUG: return "DEBUG";
+  }
+  return "UNKNOWN";
+}
+
+log_target_type_t log_target_parse_type(const char* conf)
+{
+  if(!conf)
+    return TARGET_UNKNOWN;
+
+  if(!strncmp(conf, "syslog", 6)) return TARGET_SYSLOG;
+  if(!strncmp(conf, "file", 4)) return TARGET_FILE;
+  if(!strncmp(conf, "stdout", 6)) return TARGET_STDOUT;
+  if(!strncmp(conf, "stderr", 6)) return TARGET_STDERR;
+
+  return TARGET_UNKNOWN;
+}
+
+int log_targets_target_exists(log_targets_t* targets, log_target_type_t type)
+{
+  if(!targets && !targets->first_)
+    return 0;
+
+  log_target_t* tmp = targets->first_;
+  while(tmp) {
+    if(tmp->type_ == type)
+      return 1;
+    tmp = tmp->next_;
+  }
+  return 0;
+}
+
+int log_targets_add(log_targets_t* targets, const char* conf)
+{
+  if(!targets)
+    return -1;
+
+  log_target_t* new_target = NULL;
+  int duplicates_allowed = 0;
+  switch(log_target_parse_type(conf)) {
+  case TARGET_SYSLOG: new_target = log_target_syslog_new(); break;
+  case TARGET_FILE: new_target = log_target_file_new(); duplicates_allowed = 1; break;
+  case TARGET_STDOUT: new_target = log_target_stdout_new(); break;
+  case TARGET_STDERR: new_target = log_target_stderr_new(); break;
+  default: return -3;
+  }
+  if(!new_target)
+    return -2;
+
+  if(!duplicates_allowed && log_targets_target_exists(targets, new_target->type_)) {
+    free(new_target);
+    return -4;
+  }
+
+  const char* prioptr = strchr(conf, ':');
+  if(!prioptr || prioptr[1] == 0) {
+    free(new_target);
+    return -1;
+  }
+  prioptr++;
+  if(!isdigit(prioptr[0]) || (prioptr[1] != 0 && prioptr[1] != ',')) {
+    free(new_target);
+    return -1;
+  }
+  new_target->max_prio_ = prioptr[0] - '0';
+  if(new_target->max_prio_ > 0)
+    new_target->enabled_ = 1;
+
+  if(new_target->init != NULL) {
+    const char* confptr = NULL;
+    if(prioptr[1] != 0)
+      confptr = prioptr+2;
+
+    int ret = (*new_target->init)(new_target, confptr);
+    if(ret) {
+      free(new_target);
+      return ret;
+    }
+  }
+
+  if(new_target->open != NULL)
+    (*new_target->open)(new_target);
+
+
+  if(!targets->first_) {
+    targets->first_ = new_target;
+  }
+  else {
+    log_target_t* tmp = targets->first_;
+    while(tmp->next_)
+      tmp = tmp->next_;
+
+    tmp->next_ = new_target;
+  }
+  return 0;
+}
+
+void log_targets_log(log_targets_t* targets, log_prio_t prio, const char* msg)
+{
+  if(!targets)
+    return;
+
+  log_target_t* tmp = targets->first_;
+  while(tmp) {
+    if(tmp->log != NULL && tmp->enabled_ && tmp->max_prio_ >= prio)
+      (*tmp->log)(tmp, prio, msg);
+
+    tmp = tmp->next_;
+  }
+}
+
+void log_targets_clear(log_targets_t* targets)
+{
+  if(!targets)
+    return;
+
+  while(targets->first_) {
+    log_target_t* tmp = targets->first_;
+    targets->first_ = tmp->next_;
+    if(tmp->close != NULL)
+      (*tmp->close)(tmp);
+    if(tmp->clear != NULL)
+      (*tmp->clear)(tmp);
+    free(tmp);
+  }
+}
+
+
+void log_init()
+{
+  stdlog.max_prio_ = 0;
+  stdlog.targets_.first_ = NULL;
+  g_mutex_init(&(stdlog.log_mutex_));
+}
+
+void log_close()
+{
+  g_mutex_lock(&(stdlog.log_mutex_));
+  log_targets_clear(&stdlog.targets_);
+  g_mutex_unlock(&(stdlog.log_mutex_));
+}
+
+void update_max_prio()
+{
+  log_target_t* tmp = stdlog.targets_.first_;
+  while(tmp) {
+    if(tmp->enabled_ && tmp->max_prio_ > stdlog.max_prio_)
+      stdlog.max_prio_ = tmp->max_prio_;
+
+    tmp = tmp->next_;
+  }
+}
+
+int log_add_target(const char* conf)
+{
+  if(!conf)
+    return -1;
+
+  g_mutex_lock(&(stdlog.log_mutex_));
+  int ret = log_targets_add(&stdlog.targets_, conf);
+  if(!ret) update_max_prio();
+  g_mutex_unlock(&(stdlog.log_mutex_));
+  return ret;
+}
+
+void log_printf(log_prio_t prio, const char* fmt, ...)
+{
+  if(stdlog.max_prio_ < prio)
+    return;
+
+  static char msg[MSG_LENGTH_MAX];
+  va_list args;
+
+  va_start(args, fmt);
+  vsnprintf(msg, MSG_LENGTH_MAX, fmt, args);
+  va_end(args);
+
+  g_mutex_lock(&(stdlog.log_mutex_));
+  log_targets_log(&stdlog.targets_, prio, msg);
+  g_mutex_unlock(&(stdlog.log_mutex_));
+}
+
+void log_print_hex_dump(log_prio_t prio, const u_int8_t* buf, u_int32_t len)
+{
+  if(stdlog.max_prio_ < prio)
+    return;
+
+  static char msg[MSG_LENGTH_MAX];
+
+  if(!buf) {
+    snprintf(msg, MSG_LENGTH_MAX, "(NULL)");
+  }
+  else {
+    u_int32_t i;
+    int offset = snprintf(msg, MSG_LENGTH_MAX, "dump(%d): ", len);
+    if(offset < 0)
+      return;
+    char* ptr = &msg[offset];
+
+    for(i=0; i < len; i++) {
+      if(((i+1)*3) >= (MSG_LENGTH_MAX - offset))
+        break;
+      snprintf(ptr, 3, "%02X ", buf[i]);
+      ptr+=3;
+    }
+  }
+  g_mutex_lock(&(stdlog.log_mutex_));
+  log_targets_log(&stdlog.targets_, prio, msg);
+  g_mutex_unlock(&(stdlog.log_mutex_));
+}
diff --git a/src/log.h b/src/log.h
new file mode 100644
index 0000000..3a9c3e2
--- /dev/null
+++ b/src/log.h
@@ -0,0 +1,87 @@
+/*
+ *  sydra
+ *
+ *  sydra is a toolbox which allows you to set up multiple bidirectional
+ *  Video/Audio streams from external locations.
+ *  sydra has been written to be used for the Elevate Festival in Graz
+ *  Austria in order to involve external locations to present themselves
+ *  at the festival.
+ *  Sydra is based on GStreamer and is written in C.
+ *
+ *
+ *  Copyright (C) 2014 Christian Pointner <equinox@helsinki.at>
+ *
+ *  This file is part of sydra.
+ *
+ *  sydra 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
+ *  any later version.
+ *
+ *  sydra 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 sydra. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef SYDRA_log_h_INCLUDED
+#define SYDRA_log_h_INCLUDED
+
+#include <glib.h>
+
+#define MSG_LENGTH_MAX 1024
+
+enum log_prio_enum { ERROR = 1, WARNING = 2, NOTICE = 3,
+                     INFO = 4, DEBUG = 5 };
+typedef enum log_prio_enum log_prio_t;
+
+const char* log_prio_to_string(log_prio_t prio);
+
+enum log_target_type_enum { TARGET_SYSLOG , TARGET_STDOUT, TARGET_STDERR, TARGET_FILE , TARGET_UNKNOWN };
+typedef enum log_target_type_enum log_target_type_t;
+
+struct log_target_struct {
+  log_target_type_t type_;
+  int (*init)(struct log_target_struct* self, const char* conf);
+  void (*open)(struct log_target_struct* self);
+  void (*log)(struct log_target_struct* self, log_prio_t prio, const char* msg);
+  void (*close)(struct log_target_struct* self);
+  void (*clear)(struct log_target_struct* self);
+  int opened_;
+  int enabled_;
+  log_prio_t max_prio_;
+  void* param_;
+  struct log_target_struct* next_;
+};
+typedef struct log_target_struct log_target_t;
+
+
+struct log_targets_struct {
+  log_target_t* first_;
+};
+typedef struct log_targets_struct log_targets_t;
+
+int log_targets_target_exists(log_targets_t* targets, log_target_type_t type);
+int log_targets_add(log_targets_t* targets, const char* conf);
+void log_targets_log(log_targets_t* targets, log_prio_t prio, const char* msg);
+void log_targets_clear(log_targets_t* targets);
+
+
+struct log_struct {
+  log_prio_t max_prio_;
+  log_targets_t targets_;
+  GMutex log_mutex_;
+};
+typedef struct log_struct log_t;
+
+void log_init();
+void log_close();
+void update_max_prio();
+int log_add_target(const char* conf);
+void log_printf(log_prio_t prio, const char* fmt, ...);
+void log_print_hex_dump(log_prio_t prio, const u_int8_t* buf, u_int32_t len);
+
+#endif
diff --git a/src/log_targets.h b/src/log_targets.h
new file mode 100644
index 0000000..de17f39
--- /dev/null
+++ b/src/log_targets.h
@@ -0,0 +1,357 @@
+/*
+ *  sydra
+ *
+ *  sydra is a toolbox which allows you to set up multiple bidirectional
+ *  Video/Audio streams from external locations.
+ *  sydra has been written to be used for the Elevate Festival in Graz
+ *  Austria in order to involve external locations to present themselves
+ *  at the festival.
+ *  Sydra is based on GStreamer and is written in C.
+ *
+ *
+ *  Copyright (C) 2014 Christian Pointner <equinox@helsinki.at>
+ *
+ *  This file is part of sydra.
+ *
+ *  sydra 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
+ *  any later version.
+ *
+ *  sydra 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 sydra. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef SYDRA_log_targets_h_INCLUDED
+#define SYDRA_log_targets_h_INCLUDED
+
+#include <time.h>
+
+static char* get_time_formatted()
+{
+  char* time_string;
+  time_t t = time(NULL);
+  if(t < 0)
+    time_string = "<time read error>";
+  else {
+    time_string = ctime(&t);
+    if(!time_string)
+      time_string = "<time format error>";
+    else {
+      char* newline = strchr(time_string, '\n');
+      if(newline)
+        newline[0] = 0;
+    }
+  }
+  return time_string;
+}
+
+enum syslog_facility_enum { USER = LOG_USER, MAIL = LOG_MAIL,
+                            DAEMON = LOG_DAEMON, AUTH = LOG_AUTH,
+                            SYSLOG = LOG_SYSLOG, LPR = LOG_LPR,
+                            NEWS = LOG_NEWS, UUCP = LOG_UUCP,
+                            CRON = LOG_CRON, AUTHPRIV = LOG_AUTHPRIV,
+                            FTP = LOG_FTP, LOCAL0 = LOG_LOCAL0,
+                            LOCAL1 = LOG_LOCAL1, LOCAL2 = LOG_LOCAL2,
+                            LOCAL3 = LOG_LOCAL3, LOCAL4 = LOG_LOCAL4,
+                            LOCAL5 = LOG_LOCAL5, LOCAL6 = LOG_LOCAL6,
+                            LOCAL7 = LOG_LOCAL7 };
+typedef enum syslog_facility_enum syslog_facility_t;
+
+struct log_target_syslog_param_struct {
+  char* logname_;
+  syslog_facility_t facility_;
+};
+typedef struct log_target_syslog_param_struct log_target_syslog_param_t;
+
+int log_target_syslog_init(log_target_t* self, const char* conf)
+{
+  if(!self || (conf && conf[0] == 0))
+    return -1;
+
+  self->param_ = malloc(sizeof(log_target_syslog_param_t));
+  if(!self->param_)
+    return -2;
+
+  char* logname;
+  const char* end = NULL;
+  if(!conf)
+    logname = strdup("sydra");
+  else {
+    end = strchr(conf, ',');
+    if(end) {
+      size_t len = (size_t)(end - conf);
+      if(!len) {
+        free(self->param_);
+        return -1;
+      }
+      logname = malloc(len+1);
+      if(logname) {
+        strncpy(logname, conf, len);
+        logname[len] = 0;
+      }
+    }
+    else
+      logname = strdup(conf);
+  }
+
+  if(!logname) {
+    free(self->param_);
+    return -2;
+  }
+  ((log_target_syslog_param_t*)(self->param_))->logname_ = logname;
+
+  if(!end) {
+    ((log_target_syslog_param_t*)(self->param_))->facility_ = DAEMON;
+    return 0;
+  }
+
+  if(end[1] == 0 || end[1] == ',') {
+    free(logname);
+    free(self->param_);
+    return -1;
+  }
+
+  const char* start = end + 1;
+  end = strchr(start, ',');
+  int i;
+  for(i=0;;++i) {
+    if(facilitynames[i].c_name == NULL) {
+      free(logname);
+      free(self->param_);
+      return -1;
+    }
+
+    if(( end && !strncmp(start, facilitynames[i].c_name, (size_t)(end - start)) && facilitynames[i].c_name[(size_t)(end-start)] == 0) ||
+       (!end && !strcmp(start, facilitynames[i].c_name))) {
+        ((log_target_syslog_param_t*)(self->param_))->facility_ = facilitynames[i].c_val;
+        break;
+    }
+  }
+
+  return 0;
+}
+
+void log_target_syslog_open(log_target_t* self)
+{
+  if(!self || !self->param_)
+    return;
+
+  openlog(((log_target_syslog_param_t*)(self->param_))->logname_, LOG_PID, ((log_target_syslog_param_t*)(self->param_))->facility_);
+  self->opened_ = 1;
+}
+
+void log_target_syslog_log(log_target_t* self, log_prio_t prio, const char* msg)
+{
+  if(!self || !self->param_ || !self->opened_)
+    return;
+
+  syslog((prio + 2) | ((log_target_syslog_param_t*)(self->param_))->facility_, "%s", msg);
+}
+
+void log_target_syslog_close(log_target_t* self)
+{
+  closelog();
+  self->opened_ = 0;
+}
+
+void log_target_syslog_clear(log_target_t* self)
+{
+  if(!self || !self->param_)
+    return;
+
+  if(((log_target_syslog_param_t*)(self->param_))->logname_)
+    free(((log_target_syslog_param_t*)(self->param_))->logname_);
+
+  free(self->param_);
+}
+
+log_target_t* log_target_syslog_new()
+{
+  log_target_t* tmp = malloc(sizeof(log_target_t));
+  if(!tmp)
+    return NULL;
+
+  tmp->type_ = TARGET_SYSLOG;
+  tmp->init = &log_target_syslog_init;
+  tmp->open = &log_target_syslog_open;
+  tmp->log = &log_target_syslog_log;
+  tmp->close = &log_target_syslog_close;
+  tmp->clear = &log_target_syslog_clear;
+  tmp->opened_ = 0;
+  tmp->enabled_ = 0;
+  tmp->max_prio_ = NOTICE;
+  tmp->param_ = NULL;
+  tmp->next_ = NULL;
+
+  return tmp;
+}
+
+
+struct log_target_file_param_struct {
+  char* logfilename_;
+  FILE* file_;
+};
+typedef struct log_target_file_param_struct log_target_file_param_t;
+
+int log_target_file_init(log_target_t* self, const char* conf)
+{
+  if(!self || (conf && conf[0] == 0))
+    return -1;
+
+  self->param_ = malloc(sizeof(log_target_file_param_t));
+  if(!self->param_)
+    return -2;
+
+  char* logfilename;
+  if(!conf)
+    logfilename = strdup("sydra.log");
+  else {
+    const char* end = strchr(conf, ',');
+    if(end) {
+      size_t len = (size_t)(end - conf);
+      if(!len) {
+        free(self->param_);
+        return -1;
+      }
+      logfilename = malloc(len+1);
+      if(logfilename) {
+        strncpy(logfilename, conf, len);
+        logfilename[len] = 0;
+      }
+    }
+    else
+      logfilename = strdup(conf);
+  }
+
+  if(!logfilename) {
+    free(self->param_);
+    return -2;
+  }
+  ((log_target_file_param_t*)(self->param_))->logfilename_ = logfilename;
+  ((log_target_file_param_t*)(self->param_))->file_ = NULL;
+
+  return 0;
+}
+
+void log_target_file_open(log_target_t* self)
+{
+  if(!self || !self->param_)
+    return;
+
+  ((log_target_file_param_t*)(self->param_))->file_ = fopen(((log_target_file_param_t*)(self->param_))->logfilename_, "w");
+  if(((log_target_file_param_t*)(self->param_))->file_)
+    self->opened_ = 1;
+}
+
+void log_target_file_log(log_target_t* self, log_prio_t prio, const char* msg)
+{
+  if(!self || !self->param_ || !self->opened_)
+    return;
+
+  fprintf(((log_target_file_param_t*)(self->param_))->file_, "%s %s: %s\n", get_time_formatted(), log_prio_to_string(prio), msg);
+  fflush(((log_target_file_param_t*)(self->param_))->file_);
+}
+
+void log_target_file_close(log_target_t* self)
+{
+  if(!self || !self->param_)
+    return;
+
+  fclose(((log_target_file_param_t*)(self->param_))->file_);
+  self->opened_ = 0;
+}
+
+void log_target_file_clear(log_target_t* self)
+{
+  if(!self || !self->param_)
+    return;
+
+  if(((log_target_file_param_t*)(self->param_))->logfilename_)
+    free(((log_target_file_param_t*)(self->param_))->logfilename_);
+
+  free(self->param_);
+}
+
+
+log_target_t* log_target_file_new()
+{
+  log_target_t* tmp = malloc(sizeof(log_target_t));
+  if(!tmp)
+    return NULL;
+
+  tmp->type_ = TARGET_FILE;
+  tmp->init = &log_target_file_init;
+  tmp->open = &log_target_file_open;
+  tmp->log = &log_target_file_log;
+  tmp->close = &log_target_file_close;
+  tmp->clear = &log_target_file_clear;
+  tmp->opened_ = 0;
+  tmp->enabled_ = 0;
+  tmp->max_prio_ = NOTICE;
+  tmp->param_ = NULL;
+  tmp->next_ = NULL;
+
+  return tmp;
+}
+
+
+void log_target_stdout_log(log_target_t* self, log_prio_t prio, const char* msg)
+{
+  printf("%s %s: %s\n", get_time_formatted(), log_prio_to_string(prio), msg);
+}
+
+log_target_t* log_target_stdout_new()
+{
+  log_target_t* tmp = malloc(sizeof(log_target_t));
+  if(!tmp)
+    return NULL;
+
+  tmp->type_ = TARGET_STDOUT;
+  tmp->init = NULL;
+  tmp->open = NULL;
+  tmp->log = &log_target_stdout_log;
+  tmp->close = NULL;
+  tmp->clear = NULL;
+  tmp->opened_ = 0;
+  tmp->enabled_ = 0;
+  tmp->max_prio_ = NOTICE;
+  tmp->param_ = NULL;
+  tmp->next_ = NULL;
+
+  return tmp;
+}
+
+
+void log_target_stderr_log(log_target_t* self, log_prio_t prio, const char* msg)
+{
+  fprintf(stderr, "%s %s: %s\n", get_time_formatted(), log_prio_to_string(prio), msg);
+}
+
+log_target_t* log_target_stderr_new()
+{
+  log_target_t* tmp = malloc(sizeof(log_target_t));
+  if(!tmp)
+    return NULL;
+
+  tmp->type_ = TARGET_STDERR;
+  tmp->init = NULL;
+  tmp->open = NULL;
+  tmp->log = &log_target_stderr_log;
+  tmp->close = NULL;
+  tmp->clear = NULL;
+  tmp->opened_ = 0;
+  tmp->enabled_ = 0;
+  tmp->max_prio_ = NOTICE;
+  tmp->param_ = NULL;
+  tmp->next_ = NULL;
+
+  return tmp;
+}
+
+#endif
diff --git a/src/options.c b/src/options.c
new file mode 100644
index 0000000..1273542
--- /dev/null
+++ b/src/options.c
@@ -0,0 +1,337 @@
+/*
+ *  sydra
+ *
+ *  sydra is a toolbox which allows you to set up multiple bidirectional
+ *  Video/Audio streams from external locations.
+ *  sydra has been written to be used for the Elevate Festival in Graz
+ *  Austria in order to involve external locations to present themselves
+ *  at the festival.
+ *  Sydra is based on GStreamer and is written in C.
+ *
+ *
+ *  Copyright (C) 2014 Christian Pointner <equinox@helsinki.at>
+ *
+ *  This file is part of sydra.
+ *
+ *  sydra 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
+ *  any later version.
+ *
+ *  sydra 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 sydra. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "datatypes.h"
+#include "config.h"
+
+#include "options.h"
+#include "log.h"
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <ctype.h>
+
+#define PARSE_BOOL_PARAM(SHORT, LONG, VALUE)             \
+    else if(!strcmp(str,SHORT) || !strcmp(str,LONG))     \
+      VALUE = 1;
+
+#define PARSE_INVERSE_BOOL_PARAM(SHORT, LONG, VALUE)     \
+    else if(!strcmp(str,SHORT) || !strcmp(str,LONG))     \
+      VALUE = 0;
+
+#define PARSE_INT_PARAM(SHORT, LONG, VALUE, BASE)        \
+    else if(!strcmp(str,SHORT) || !strcmp(str,LONG))     \
+    {                                                    \
+      if(argc < 1)                                       \
+        return i;                                        \
+      VALUE = strtol(argv[i+1], (char **)NULL, BASE);    \
+      argc--;                                            \
+      i++;                                               \
+    }
+
+#define PARSE_STRING_PARAM(SHORT, LONG, VALUE)           \
+    else if(!strcmp(str,SHORT) || !strcmp(str,LONG))     \
+    {                                                    \
+      if(argc < 1 || argv[i+1][0] == '-')                \
+        return i;                                        \
+      if(VALUE) free(VALUE);                             \
+      VALUE = strdup(argv[i+1]);                         \
+      if(!VALUE)                                         \
+        return -2;                                       \
+      argc--;                                            \
+      i++;                                               \
+    }
+
+#define PARSE_STRING_PARAM_SEC(SHORT, LONG, VALUE)       \
+    else if(!strcmp(str,SHORT) || !strcmp(str,LONG))     \
+    {                                                    \
+      if(argc < 1 || argv[i+1][0] == '-')                \
+        return i;                                        \
+      if(VALUE) free(VALUE);                             \
+      VALUE = strdup(argv[i+1]);                         \
+      if(!VALUE)                                         \
+        return -2;                                       \
+      size_t j;                                          \
+      for(j=0; j < strlen(argv[i+1]); ++j)               \
+        argv[i+1][j] = '#';                              \
+      argc--;                                            \
+      i++;                                               \
+    }
+
+#define PARSE_HEXSTRING_PARAM_SEC(SHORT, LONG, VALUE)    \
+    else if(!strcmp(str,SHORT) || !strcmp(str,LONG))     \
+    {                                                    \
+      if(argc < 1 || argv[i+1][0] == '-')                \
+        return i;                                        \
+      int ret;                                           \
+      ret = options_parse_hex_string(argv[i+1], &VALUE); \
+      if(ret > 0)                                        \
+        return i+1;                                      \
+      else if(ret < 0)                                   \
+        return ret;                                      \
+      size_t j;                                          \
+      for(j=0; j < strlen(argv[i+1]); ++j)               \
+        argv[i+1][j] = '#';                              \
+      argc--;                                            \
+      i++;                                               \
+    }
+
+#define PARSE_STRING_LIST(SHORT, LONG, LIST)             \
+    else if(!strcmp(str,SHORT) || !strcmp(str,LONG))     \
+    {                                                    \
+      if(argc < 1 || argv[i+1][0] == '-')                \
+        return i;                                        \
+      int ret = string_list_add(&LIST, argv[i+1]);       \
+      if(ret == -2)                                      \
+        return ret;                                      \
+      else if(ret)                                       \
+        return i+1;                                      \
+      argc--;                                            \
+      i++;                                               \
+    }
+
+#define PARSE_RESOLV_TYPE(SHORT, LONG, VALUE)            \
+    else if(!strcmp(str,SHORT) || !strcmp(str,LONG))     \
+    {                                                    \
+      if(argc < 1 || argv[i+1][0] == '-')                \
+        return i;                                        \
+      if(!strcmp(argv[i+1], "4") ||                      \
+         !strcmp(argv[i+1], "ipv4"))                     \
+        VALUE = IPV4_ONLY;                               \
+      else if(!strcmp(argv[i+1], "6") ||                 \
+              !strcmp(argv[i+1], "ipv6"))                \
+        VALUE = IPV6_ONLY;                               \
+      else                                               \
+        return i+1;                                      \
+      argc--;                                            \
+      i++;                                               \
+    }
+
+int options_parse_hex_string(const char* hex, buffer_t* buffer)
+{
+  if(!hex || !buffer)
+    return -1;
+
+  u_int32_t hex_len = strlen(hex);
+  if(hex_len%2)
+    return 1;
+
+  if(buffer->buf_)
+    free(buffer->buf_);
+
+  buffer->length_ = hex_len/2;
+  buffer->buf_ = malloc(buffer->length_);
+  if(!buffer->buf_) {
+    buffer->length_ = 0;
+    return -2;
+  }
+
+  const char* ptr = hex;
+  int i;
+  for(i=0;i<buffer->length_;++i) {
+    u_int32_t tmp;
+    sscanf(ptr, "%2X", &tmp);
+    buffer->buf_[i] = (u_int8_t)tmp;
+    ptr += 2;
+  }
+
+  return 0;
+}
+
+
+int options_parse(options_t* opt, int argc, char* argv[])
+{
+  if(!opt)
+    return -1;
+
+  options_default(opt);
+
+  if(opt->progname_)
+    free(opt->progname_);
+  opt->progname_ = strdup(argv[0]);
+  if(!opt->progname_)
+    return -2;
+
+  argc--;
+
+  int i;
+  for(i=1; argc > 0; ++i)
+  {
+    char* str = argv[i];
+    argc--;
+
+    if(!strcmp(str,"-h") || !strcmp(str,"--help"))
+      return -1;
+    else if(!strcmp(str,"-v") || !strcmp(str,"--version"))
+      return -3;
+    PARSE_INVERSE_BOOL_PARAM("-D","--nodaemonize", opt->daemonize_)
+    PARSE_STRING_PARAM("-u","--username", opt->username_)
+    PARSE_STRING_PARAM("-g","--groupname", opt->groupname_)
+    PARSE_STRING_PARAM("-C","--chroot", opt->chroot_dir_)
+    PARSE_STRING_PARAM("-P","--write-pid", opt->pid_file_)
+    PARSE_STRING_LIST("-L","--log", opt->log_targets_)
+    PARSE_BOOL_PARAM("-U", "--debug", opt->debug_)
+    PARSE_STRING_PARAM("-s","--source", opt->src_bin_desc_)
+    PARSE_STRING_PARAM("-d","--output-dir", opt->output_dir_)
+    PARSE_STRING_PARAM("-f","--name-format", opt->name_format_)
+    PARSE_INT_PARAM("-m","--mode", opt->mode_, 8)
+    PARSE_BOOL_PARAM("-n", "--nocache", opt->nocache_)
+    PARSE_INT_PARAM("-i","--interval", opt->interval_, 10)
+    PARSE_INT_PARAM("-o","--offset", opt->offset_, 10)
+    PARSE_STRING_PARAM("-x","--post-process", opt->post_process_)
+    else
+      return i;
+  }
+
+  if(opt->interval_ <= 0)
+    return -4;
+
+  if(opt->debug_) {
+    string_list_add(&opt->log_targets_, "stdout:5");
+    opt->daemonize_ = 0;
+  }
+
+  if(!opt->log_targets_.first_) {
+    string_list_add(&opt->log_targets_, "syslog:3,sydra,daemon");
+  }
+
+  return 0;
+}
+
+void options_parse_post(options_t* opt)
+{
+  if(!opt)
+    return;
+
+// nothing yet
+}
+
+void options_default(options_t* opt)
+{
+  if(!opt)
+    return;
+
+  opt->progname_ = strdup("sydra");
+  opt->daemonize_ = 1;
+  opt->username_ = NULL;
+  opt->groupname_ = NULL;
+  opt->chroot_dir_ = NULL;
+  opt->pid_file_ = NULL;
+  string_list_init(&opt->log_targets_);
+  opt->debug_ = 0;
+  opt->src_bin_desc_ = NULL;
+  opt->output_dir_ = strdup("/srv/archiv");
+  opt->name_format_ = strdup("%Y-%m-%d-%H00.ogg");
+  opt->mode_ = 0644;
+  opt->nocache_ = 0;
+  opt->interval_ = 50;
+  opt->offset_ = 0;
+  opt->post_process_ = NULL;
+}
+
+void options_clear(options_t* opt)
+{
+  if(!opt)
+    return;
+
+  if(opt->progname_)
+    free(opt->progname_);
+  if(opt->username_)
+    free(opt->username_);
+  if(opt->groupname_)
+    free(opt->groupname_);
+  if(opt->chroot_dir_)
+    free(opt->chroot_dir_);
+  if(opt->pid_file_)
+    free(opt->pid_file_);
+  string_list_clear(&opt->log_targets_);
+  if(opt->src_bin_desc_)
+    free(opt->src_bin_desc_);
+  if(opt->output_dir_)
+    free(opt->output_dir_);
+  if(opt->name_format_)
+    free(opt->name_format_);
+  if(opt->post_process_)
+    free(opt->post_process_);
+}
+
+void options_print_usage()
+{
+  printf("USAGE:\n");
+  printf("sydra     [-h|--help]                          prints this...\n");
+  printf("          [-v|--version]                       print version info and exit\n");
+  printf("          [-D|--nodaemonize]                   don't run in background\n");
+  printf("          [-u|--username] <username>           change to this user\n");
+  printf("          [-g|--groupname] <groupname>         change to this group\n");
+  printf("          [-C|--chroot] <path>                 chroot to this directory\n");
+  printf("          [-P|--write-pid] <path>              write pid to this file\n");
+  printf("          [-L|--log] <target>:<level>[,<param1>[,<param2>..]]\n");
+  printf("                                               add a log target, can be invoked several times\n");
+  printf("          [-U|--debug]                         don't daemonize and log to stdout with maximum log level\n");
+  printf("          [-s|--source] <description>          a gstreamer pipeline-style description which will be used\n");
+  printf("                                               as data source, see gst-launch man-page for syntax\n");
+  printf("          [-d|--output-dir] <path>             path to the output directory\n");
+  printf("          [-f|--name-format] <format>          the file name format, see manpage of strftime for the syntax\n");
+  printf("          [-m|--mode] <value>                  octal representation of the file permission mode\n");
+  printf("          [-n|--nocache]                       Use O_DIRECT for recorded files\n");
+  printf("          [-i|--interval] <value>              interval for time checks in ms\n");
+  printf("          [-o|--offset] <value>                time offset for recordings in ms\n");
+  printf("          [-x|--post-process] <script>         call script when file is finished\n");
+}
+
+void options_print_version()
+{
+  printf("%s\n", VERSION_STRING_0);
+  printf("%s\n", VERSION_STRING_1);
+}
+
+void options_print(options_t* opt)
+{
+  if(!opt)
+    return;
+
+  printf("progname: '%s'\n", opt->progname_);
+  printf("daemonize: %d\n", opt->daemonize_);
+  printf("username: '%s'\n", opt->username_);
+  printf("groupname: '%s'\n", opt->groupname_);
+  printf("chroot_dir: '%s'\n", opt->chroot_dir_);
+  printf("pid_file: '%s'\n", opt->pid_file_);
+  printf("log_targets: \n");
+  string_list_print(&opt->log_targets_, "  '", "'\n");
+  printf("debug: %s\n", !opt->debug_ ? "false" : "true");
+  printf("src_bin_desc: >>%s<<\n", opt->src_bin_desc_);
+  printf("output_dir: '%s'\n", opt->output_dir_);
+  printf("name_format: '%s'\n", opt->name_format_);
+  printf("mode: %04o\n", (int)opt->mode_);
+  printf("nocache: %s\n", !opt->nocache_ ? "false" : "true");
+  printf("interval: %d\n", opt->interval_);
+  printf("offset: %d\n", opt->offset_);
+  printf("post_process: '%s'\n", opt->post_process_);
+}
diff --git a/src/options.h b/src/options.h
new file mode 100644
index 0000000..465291c
--- /dev/null
+++ b/src/options.h
@@ -0,0 +1,67 @@
+/*
+ *  sydra
+ *
+ *  sydra is a toolbox which allows you to set up multiple bidirectional
+ *  Video/Audio streams from external locations.
+ *  sydra has been written to be used for the Elevate Festival in Graz
+ *  Austria in order to involve external locations to present themselves
+ *  at the festival.
+ *  Sydra is based on GStreamer and is written in C.
+ *
+ *
+ *  Copyright (C) 2014 Christian Pointner <equinox@helsinki.at>
+ *
+ *  This file is part of sydra.
+ *
+ *  sydra 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
+ *  any later version.
+ *
+ *  sydra 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 sydra. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef SYDRA_options_h_INCLUDED
+#define SYDRA_options_h_INCLUDED
+
+#include <sys/types.h>
+#include "string_list.h"
+#include "datatypes.h"
+
+struct options_struct {
+  char* progname_;
+  int daemonize_;
+  char* username_;
+  char* groupname_;
+  char* chroot_dir_;
+  char* pid_file_;
+  string_list_t log_targets_;
+  int debug_;
+  char* src_bin_desc_;
+  char* output_dir_;
+  char* name_format_;
+  mode_t mode_;
+  int nocache_;
+  int interval_;
+  int offset_;
+  char* post_process_;
+};
+typedef struct options_struct options_t;
+
+int options_parse_hex_string(const char* hex, buffer_t* buffer);
+
+int options_parse(options_t* opt, int argc, char* argv[]);
+void options_parse_post(options_t* opt);
+void options_default(options_t* opt);
+void options_clear(options_t* opt);
+void options_print_usage();
+void options_print_version();
+void options_print(options_t* opt);
+
+#endif
diff --git a/src/sig_handler.c b/src/sig_handler.c
new file mode 100644
index 0000000..9a77d39
--- /dev/null
+++ b/src/sig_handler.c
@@ -0,0 +1,113 @@
+/*
+ *  sydra
+ *
+ *  sydra is a toolbox which allows you to set up multiple bidirectional
+ *  Video/Audio streams from external locations.
+ *  sydra has been written to be used for the Elevate Festival in Graz
+ *  Austria in order to involve external locations to present themselves
+ *  at the festival.
+ *  Sydra is based on GStreamer and is written in C.
+ *
+ *
+ *  Copyright (C) 2014 Christian Pointner <equinox@helsinki.at>
+ *
+ *  This file is part of sydra.
+ *
+ *  sydra 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
+ *  any later version.
+ *
+ *  sydra 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 sydra. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "datatypes.h"
+
+#include "log.h"
+
+#include "sig_handler.h"
+
+#include <glib.h>
+#include <errno.h>
+
+static GThread *signal_thread;
+
+void signal_init()
+{
+  sigset_t signal_set;
+
+  sigemptyset(&signal_set);
+  sigaddset(&signal_set, SIGINT);
+  sigaddset(&signal_set, SIGQUIT);
+  sigaddset(&signal_set, SIGHUP);
+  sigaddset(&signal_set, SIGTERM);
+  sigaddset(&signal_set, SIGUSR1);
+  sigaddset(&signal_set, SIGUSR2);
+
+  pthread_sigmask(SIG_BLOCK, &signal_set, NULL);
+}
+
+static gpointer signal_thread_func(gpointer data)
+{
+  GMainLoop *loop = (GMainLoop *)data;
+
+  struct timespec timeout;
+  sigset_t signal_set;
+  int sig_num;
+  for(;;) {
+    sigemptyset(&signal_set);
+    sigaddset(&signal_set, SIGINT);
+    sigaddset(&signal_set, SIGQUIT);
+    sigaddset(&signal_set, SIGHUP);
+    sigaddset(&signal_set, SIGTERM);
+    sigaddset(&signal_set, SIGUSR1);
+    sigaddset(&signal_set, SIGUSR2);
+    timeout.tv_sec = 1;
+    timeout.tv_nsec = 0;
+    sig_num = sigtimedwait(&signal_set, NULL, &timeout);
+    if(sig_num == -1) {
+      if(errno != EINTR && errno != EAGAIN) {
+        log_printf(ERROR, "sigwait failed with error: %d, signal handling will be disabled", errno);
+        break;
+      }
+    } else {
+        switch(sig_num) {
+        case SIGTERM:
+        case SIGINT:
+        case SIGQUIT: {
+          log_printf(NOTICE, "signal %d received, exiting", sig_num);
+          g_main_loop_quit(loop);
+          break;
+        }
+        default: {
+          log_printf(NOTICE, "signal %d received, ignoring", sig_num);
+          break;
+        }
+      }
+    }
+  }
+
+  return NULL;
+}
+
+int signal_start(GMainLoop *loop)
+{
+  g_assert(!signal_thread);
+
+  signal_thread = g_thread_new("sig_handler", signal_thread_func, loop);
+  if(!signal_thread)
+    return -1;
+
+  return 0;
+}
+
+void signal_stop()
+{
+      // nothing yet..
+}
diff --git a/src/sig_handler.h b/src/sig_handler.h
new file mode 100644
index 0000000..739cdc2
--- /dev/null
+++ b/src/sig_handler.h
@@ -0,0 +1,39 @@
+/*
+ *  sydra
+ *
+ *  sydra is a toolbox which allows you to set up multiple bidirectional
+ *  Video/Audio streams from external locations.
+ *  sydra has been written to be used for the Elevate Festival in Graz
+ *  Austria in order to involve external locations to present themselves
+ *  at the festival.
+ *  Sydra is based on GStreamer and is written in C.
+ *
+ *
+ *  Copyright (C) 2014 Christian Pointner <equinox@helsinki.at>
+ *
+ *  This file is part of sydra.
+ *
+ *  sydra 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
+ *  any later version.
+ *
+ *  sydra 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 sydra. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef SYDRA_sig_handler_h_INCLUDED
+#define SYDRA_sig_handler_h_INCLUDED
+
+#include <glib.h>
+
+void signal_init();
+int signal_start(GMainLoop *loop);
+void signal_stop();
+
+#endif
diff --git a/src/slist.c b/src/slist.c
new file mode 100644
index 0000000..884339f
--- /dev/null
+++ b/src/slist.c
@@ -0,0 +1,132 @@
+/*
+ *  sydra
+ *
+ *  sydra is a toolbox which allows you to set up multiple bidirectional
+ *  Video/Audio streams from external locations.
+ *  sydra has been written to be used for the Elevate Festival in Graz
+ *  Austria in order to involve external locations to present themselves
+ *  at the festival.
+ *  Sydra is based on GStreamer and is written in C.
+ *
+ *
+ *  Copyright (C) 2014 Christian Pointner <equinox@helsinki.at>
+ *
+ *  This file is part of sydra.
+ *
+ *  sydra 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
+ *  any later version.
+ *
+ *  sydra 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 sydra. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <unistd.h>
+#include <stdlib.h>
+
+#include "datatypes.h"
+
+#include "slist.h"
+
+slist_element_t* slist_get_last(slist_element_t* first)
+{
+  if(!first)
+    return NULL;
+
+  while(first->next_)
+    first = first->next_;
+
+  return first;
+}
+
+int slist_init(slist_t* lst, void (*delete_element)(void*))
+{
+  if(!lst || !delete_element)
+    return -1;
+
+  lst->delete_element = delete_element;
+  lst->first_ = NULL;
+
+  return 0;
+}
+
+slist_element_t* slist_add(slist_t* lst, void* data)
+{
+  if(!lst || !data)
+    return NULL;
+
+  slist_element_t* new_element = malloc(sizeof(slist_element_t));
+  if(!new_element)
+    return NULL;
+
+  new_element->data_ = data;
+  new_element->next_ = NULL;
+
+  if(!lst->first_)
+    lst->first_ = new_element;
+  else
+    slist_get_last(lst->first_)->next_ = new_element;
+
+  return new_element;
+}
+
+void slist_remove(slist_t* lst, void* data)
+{
+  if(!lst || !lst->first_ || !data)
+    return;
+
+  slist_element_t* tmp = lst->first_->next_;
+  slist_element_t* prev = lst->first_;
+  if(lst->first_->data_ == data) {
+    lst->first_ = tmp;
+    lst->delete_element(prev->data_);
+    free(prev);
+  }
+  else {
+    while(tmp) {
+      if(tmp->data_ == data) {
+        prev->next_ = tmp->next_;
+        lst->delete_element(tmp->data_);
+        free(tmp);
+        return;
+      }
+      prev = tmp;
+      tmp = tmp->next_;
+    }
+  }
+}
+
+void slist_clear(slist_t* lst)
+{
+  if(!lst || !lst->first_)
+    return;
+
+  do {
+    slist_element_t* deletee = lst->first_;
+    lst->first_ = lst->first_->next_;
+    lst->delete_element(deletee->data_);
+    free(deletee);
+  }
+  while(lst->first_);
+
+  lst->first_ = NULL;
+}
+
+int slist_length(slist_t* lst)
+{
+  if(!lst || !lst->first_)
+    return 0;
+
+  int len = 0;
+  slist_element_t* tmp;
+  for(tmp = lst->first_; tmp; tmp = tmp->next_)
+    len++;
+
+  return len;
+}
diff --git a/src/slist.h b/src/slist.h
new file mode 100644
index 0000000..bc7f6ad
--- /dev/null
+++ b/src/slist.h
@@ -0,0 +1,53 @@
+/*
+ *  sydra
+ *
+ *  sydra is a toolbox which allows you to set up multiple bidirectional
+ *  Video/Audio streams from external locations.
+ *  sydra has been written to be used for the Elevate Festival in Graz
+ *  Austria in order to involve external locations to present themselves
+ *  at the festival.
+ *  Sydra is based on GStreamer and is written in C.
+ *
+ *
+ *  Copyright (C) 2014 Christian Pointner <equinox@helsinki.at>
+ *
+ *  This file is part of sydra.
+ *
+ *  sydra 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
+ *  any later version.
+ *
+ *  sydra 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 sydra. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef SYDRA_slist_h_INCLUDED
+#define SYDRA_slist_h_INCLUDED
+
+struct slist_element_struct {
+  void* data_;
+  struct slist_element_struct* next_;
+};
+typedef struct slist_element_struct slist_element_t;
+
+slist_element_t* slist_get_last(slist_element_t* first);
+
+struct slist_struct {
+  void (*delete_element)(void* element);
+  slist_element_t* first_;
+};
+typedef struct slist_struct slist_t;
+
+int slist_init(slist_t* lst, void (*delete_element)(void*));
+slist_element_t* slist_add(slist_t* lst, void* data);
+void slist_remove(slist_t* lst, void* data);
+void slist_clear(slist_t* lst);
+int slist_length(slist_t* lst);
+
+#endif
diff --git a/src/string_list.c b/src/string_list.c
new file mode 100644
index 0000000..1309745
--- /dev/null
+++ b/src/string_list.c
@@ -0,0 +1,71 @@
+/*
+ *  sydra
+ *
+ *  sydra is a toolbox which allows you to set up multiple bidirectional
+ *  Video/Audio streams from external locations.
+ *  sydra has been written to be used for the Elevate Festival in Graz
+ *  Austria in order to involve external locations to present themselves
+ *  at the festival.
+ *  Sydra is based on GStreamer and is written in C.
+ *
+ *
+ *  Copyright (C) 2014 Christian Pointner <equinox@helsinki.at>
+ *
+ *  This file is part of sydra.
+ *
+ *  sydra 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
+ *  any later version.
+ *
+ *  sydra 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 sydra. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "string_list.h"
+#include "slist.h"
+
+int string_list_init(string_list_t* list)
+{
+  return slist_init(list, &free);
+}
+
+void string_list_clear(string_list_t* list)
+{
+  slist_clear(list);
+}
+
+int string_list_add(string_list_t* list, const char* string)
+{
+  if(!list)
+    return -1;
+
+  char* tmp = strdup(string);
+  if(slist_add(list, tmp) == NULL) {
+    free(tmp);
+    return -2;
+  }
+
+  return 0;
+}
+
+void string_list_print(string_list_t* list, const char* head, const char* tail)
+{
+  if(!list)
+    return;
+
+  slist_element_t* tmp = list->first_;
+  while(tmp) {
+    printf("%s%s%s", head, (char*)(tmp->data_), tail);
+    tmp = tmp->next_;
+  }
+}
diff --git a/src/string_list.h b/src/string_list.h
new file mode 100644
index 0000000..aaa90fb
--- /dev/null
+++ b/src/string_list.h
@@ -0,0 +1,43 @@
+/*
+ *  sydra
+ *
+ *  sydra is a toolbox which allows you to set up multiple bidirectional
+ *  Video/Audio streams from external locations.
+ *  sydra has been written to be used for the Elevate Festival in Graz
+ *  Austria in order to involve external locations to present themselves
+ *  at the festival.
+ *  Sydra is based on GStreamer and is written in C.
+ *
+ *
+ *  Copyright (C) 2014 Christian Pointner <equinox@helsinki.at>
+ *
+ *  This file is part of sydra.
+ *
+ *  sydra 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
+ *  any later version.
+ *
+ *  sydra 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 sydra. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef SYDRA_string_list_h_INCLUDED
+#define SYDRA_string_list_h_INCLUDED
+
+#include "slist.h"
+
+typedef slist_t string_list_t;
+
+int string_list_init(string_list_t* list);
+void string_list_clear(string_list_t* list);
+int string_list_add(string_list_t* list, const char* string);
+
+void string_list_print(string_list_t* list, const char* head, const char* tail);
+
+#endif
diff --git a/src/sydra.c b/src/sydra.c
new file mode 100644
index 0000000..bded404
--- /dev/null
+++ b/src/sydra.c
@@ -0,0 +1,255 @@
+/*
+ *  sydra
+ *
+ *  sydra is a toolbox which allows you to set up multiple bidirectional
+ *  Video/Audio streams from external locations.
+ *  sydra has been written to be used for the Elevate Festival in Graz
+ *  Austria in order to involve external locations to present themselves
+ *  at the festival.
+ *  Sydra is based on GStreamer and is written in C.
+ *
+ *
+ *  Copyright (C) 2014 Christian Pointner <equinox@helsinki.at>
+ *
+ *  This file is part of sydra.
+ *
+ *  sydra 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
+ *  any later version.
+ *
+ *  sydra 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 sydra. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <sys/select.h>
+
+#include <gst/gst.h>
+
+#include "datatypes.h"
+#include "options.h"
+#include "string_list.h"
+#include "log.h"
+#include "sig_handler.h"
+#include "daemon.h"
+#include "writer.h"
+
+static gboolean bus_call(GstBus *bus, GstMessage *msg, gpointer data)
+{
+  GMainLoop *loop = (GMainLoop *)data;
+
+  switch (GST_MESSAGE_TYPE(msg)) {
+  case GST_MESSAGE_EOS: {
+    log_printf(NOTICE, "End of stream");
+    g_main_loop_quit(loop);
+    break;
+  }
+  case GST_MESSAGE_INFO: {
+    GError *info;
+    gst_message_parse_info(msg, &info, NULL);
+    log_printf(INFO, "%s", info->message);
+    g_error_free(info);
+    break;
+  }
+  case GST_MESSAGE_WARNING: {
+    GError *warning;
+    gst_message_parse_warning(msg, &warning, NULL);
+    log_printf(WARNING, "%s", warning->message);
+    g_error_free(warning);
+    break;
+  }
+  case GST_MESSAGE_ERROR: {
+    GError *error;
+    gst_message_parse_error(msg, &error, NULL);
+    log_printf(ERROR, "%s", error->message);
+    g_error_free(error);
+    g_main_loop_quit(loop);
+    break;
+  }
+  default:
+    break;
+  }
+  return TRUE;
+}
+
+int main_loop(options_t* opt)
+{
+  log_printf(INFO, "entering main loop");
+
+  GMainLoop *loop;
+  GstElement *pipeline, *source;
+  GstBus *bus;
+  writer_t writer;
+
+  loop = g_main_loop_new(NULL, FALSE);
+  pipeline = gst_pipeline_new("sydra");
+  if(!pipeline || !loop) {
+    log_printf(ERROR, "the pipeline/loop object could not be created. Exiting.");
+    return -1;
+  }
+
+  int ret = writer_init(&writer, loop, opt->name_format_, opt->mode_, opt->nocache_, opt->output_dir_, opt->interval_, opt->offset_, opt->post_process_);
+  if(ret) {
+    gst_object_unref(GST_OBJECT(pipeline));
+    gst_object_unref(GST_OBJECT(loop));
+    return ret;
+  }
+
+  GError *error = NULL;
+  source = gst_parse_bin_from_description(opt->src_bin_desc_, TRUE, &error);
+  if(!source || error) {
+    log_printf(ERROR, "Source Bin Description Parser Error: %s", error ? error->message : "unknown");
+    g_error_free(error);
+    gst_object_unref(GST_OBJECT(writer.sink_));
+    gst_object_unref(GST_OBJECT(pipeline));
+    gst_object_unref(GST_OBJECT(loop));
+    return -1;
+  }
+
+  gst_bin_add_many(GST_BIN(pipeline), source, writer.sink_, NULL);
+  gst_element_link_many(source, writer.sink_, NULL);
+  bus = gst_pipeline_get_bus(GST_PIPELINE(pipeline));
+  gst_bus_add_watch(bus, bus_call, loop);
+  gst_object_unref(bus);
+
+  log_printf(INFO, "Set State: Paused");
+  gst_element_set_state(pipeline, GST_STATE_PAUSED);
+  log_printf(INFO, "Set State: Playing");
+  gst_element_set_state(pipeline, GST_STATE_PLAYING);
+
+  signal_start(loop);
+  ret = writer_start(&writer);
+  if(!ret) {
+    g_main_loop_run(loop);
+    signal_stop();
+  }
+
+  log_printf(NOTICE, "Stopping pipeline");
+  gst_element_set_state (pipeline, GST_STATE_NULL);
+  writer_stop(&writer);
+  gst_object_unref(GST_OBJECT(pipeline));
+
+  return ret;
+}
+
+int main(int argc, char* argv[])
+{
+  log_init();
+
+  options_t opt;
+  int ret = options_parse(&opt, argc, argv);
+  if(ret) {
+    if(ret > 0)
+      fprintf(stderr, "syntax error near: %s\n\n", argv[ret]);
+    if(ret == -2)
+      fprintf(stderr, "memory error on options_parse, exitting\n");
+    if(ret == -3)
+      options_print_version();
+    if(ret == -4)
+      fprintf(stderr, "the interval must be bigger than 0\n");
+
+    if(ret != -2 && ret != -3 && ret != -4)
+      options_print_usage();
+
+    if(ret == -1 || ret == -3)
+      ret = 0;
+
+    options_clear(&opt);
+    log_close();
+    exit(ret);
+  }
+  slist_element_t* tmp = opt.log_targets_.first_;
+  while(tmp) {
+    ret = log_add_target(tmp->data_);
+    if(ret) {
+      switch(ret) {
+      case -2: fprintf(stderr, "memory error on log_add_target, exitting\n"); break;
+      case -3: fprintf(stderr, "unknown log target: '%s', exitting\n", (char*)(tmp->data_)); break;
+      case -4: fprintf(stderr, "this log target is only allowed once: '%s', exitting\n", (char*)(tmp->data_)); break;
+      default: fprintf(stderr, "syntax error near: '%s', exitting\n", (char*)(tmp->data_)); break;
+      }
+
+      options_clear(&opt);
+      log_close();
+      exit(ret);
+    }
+    tmp = tmp->next_;
+  }
+
+  log_printf(NOTICE, "just started...");
+  options_parse_post(&opt);
+
+  priv_info_t priv;
+  if(opt.username_)
+    if(priv_init(&priv, opt.username_, opt.groupname_)) {
+      options_clear(&opt);
+      log_close();
+      exit(-1);
+    }
+
+  FILE* pid_file = NULL;
+  if(opt.pid_file_) {
+    pid_file = fopen(opt.pid_file_, "w");
+    if(!pid_file) {
+      log_printf(WARNING, "unable to open pid file: %s", strerror(errno));
+    }
+  }
+
+  if(opt.chroot_dir_)
+    if(do_chroot(opt.chroot_dir_)) {
+      options_clear(&opt);
+      log_close();
+      exit(-1);
+    }
+  if(opt.username_)
+    if(priv_drop(&priv)) {
+      options_clear(&opt);
+      log_close();
+      exit(-1);
+    }
+
+  if(opt.daemonize_) {
+    pid_t oldpid = getpid();
+    daemonize();
+    log_printf(INFO, "running in background now (old pid: %d)", oldpid);
+  }
+
+  if(pid_file) {
+    pid_t pid = getpid();
+    fprintf(pid_file, "%d", pid);
+    fclose(pid_file);
+  }
+
+  signal_init();
+  gst_init(NULL, NULL);
+  const gchar *nano_str;
+  guint major, minor, micro, nano;
+  gst_version(&major, &minor, &micro, &nano);
+  if (nano == 1)
+    nano_str = " (CVS)";
+  else if (nano == 2)
+    nano_str = " (Prerelease)";
+  else
+    nano_str = "";
+  log_printf(NOTICE, "sydra linked against GStreamer %d.%d.%d%s", major, minor, micro, nano_str);
+
+  ret = main_loop(&opt);
+
+  options_clear(&opt);
+
+  log_printf(NOTICE, "sydra shutdown");
+
+  gst_deinit();
+  log_close();
+
+  return ret;
+}
diff --git a/src/sysexec.c b/src/sysexec.c
new file mode 100644
index 0000000..2d740ce
--- /dev/null
+++ b/src/sysexec.c
@@ -0,0 +1,226 @@
+/*
+ *  sydra
+ *
+ *  sydra is a toolbox which allows you to set up multiple bidirectional
+ *  Video/Audio streams from external locations.
+ *  sydra has been written to be used for the Elevate Festival in Graz
+ *  Austria in order to involve external locations to present themselves
+ *  at the festival.
+ *  Sydra is based on GStreamer and is written in C.
+ *
+ *
+ *  Copyright (C) 2014 Christian Pointner <equinox@helsinki.at>
+ *
+ *  This file is part of sydra.
+ *
+ *  sydra 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
+ *  any later version.
+ *
+ *  sydra 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 sydra. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "datatypes.h"
+
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <sys/wait.h>
+#include <sys/select.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "sysexec.h"
+#include "log.h"
+
+char** dup_ptrptr(char* const ptrptr[])
+{
+  if(!ptrptr)
+    return NULL;
+
+  int n = 0;
+  while(ptrptr[n])
+    n++;
+
+  char** my_ptrptr;
+  my_ptrptr = malloc((n+1)*sizeof(char*));
+  if(!my_ptrptr)
+    return NULL;
+
+  int i;
+  for(i = 0; i < n; ++i) {
+    my_ptrptr[i] = strdup(ptrptr[i]);
+    if(!my_ptrptr[i]) {
+      i--;
+      for(; i >= 0; --i)
+        free(my_ptrptr[i]);
+
+      free(my_ptrptr);
+      return NULL;
+    }
+  }
+
+  my_ptrptr[n] = NULL;
+
+  return my_ptrptr;
+}
+
+void free_ptrptr(char** ptrptr)
+{
+  if(!ptrptr)
+    return;
+
+  int i;
+  for(i = 0; ptrptr[i]; ++i)
+    free(ptrptr[i]);
+
+  free(ptrptr);
+}
+
+child_t* new_child(const char* script, char* const argv[], char* const evp[])
+{
+  child_t* new_child;
+
+  new_child = malloc(sizeof(child_t));
+  if(!new_child)
+    return NULL;
+
+  new_child->pid_ = -1;
+  new_child->err_fd_ = -1;
+  new_child->script_ = strdup(script);
+  if(!new_child->script_) {
+    free(new_child);
+    return NULL;
+  }
+
+  new_child->argv_ = dup_ptrptr(argv);
+  if(!new_child->argv_) {
+    free(new_child->script_);
+    free(new_child);
+    return NULL;
+
+  }
+
+  new_child->evp_ = dup_ptrptr(evp);
+  if(!new_child->evp_) {
+    free_ptrptr(new_child->argv_);
+    free(new_child->script_);
+    free(new_child);
+    return NULL;
+  }
+  return new_child;
+}
+
+void free_child(child_t* child)
+{
+  if(!child)
+    return;
+
+  free_ptrptr(child->argv_);
+  free_ptrptr(child->evp_);
+  if(child->script_)
+    free(child->script_);
+  if(child->err_fd_ >= 0) close(child->err_fd_);
+  free(child);
+}
+
+child_t* sydra_exec(const char* script, char* const argv[], char* const evp[])
+{
+  if(!script)
+    return NULL;
+
+  child_t* child = new_child(script, argv, evp);
+  if(!child)
+    return NULL;
+
+  int pipefd[2];
+  if(pipe(pipefd) == -1) {
+    log_printf(ERROR, "executing script '%s' failed: pipe() error: %s", child->script_, strerror(errno)); // TODO: thread safe strerror
+    free_child(child);
+    return NULL;
+  }
+
+  pid_t pid;
+  pid = fork();
+  if(pid == -1) {
+    log_printf(ERROR, "executing script '%s' failed: fork() error: %s", child->script_, strerror(errno)); // TODO: thread safe strerror
+    close(pipefd[0]);
+    close(pipefd[1]);
+    free_child(child);
+    return NULL;
+  }
+
+  if(!pid) {
+    int fd;
+    for (fd=getdtablesize();fd>=0;--fd) // close all file descriptors
+      if(fd != pipefd[1]) close(fd);
+
+    fd = open("/dev/null",O_RDWR);        // stdin
+    if(fd == -1)
+      log_printf(WARNING, "can't open stdin");
+    else {
+      if(dup(fd) == -1)   // stdout
+        log_printf(WARNING, "can't open stdout");
+      if(dup(fd) == -1)   // stderr
+        log_printf(WARNING, "can't open stderr");
+    }
+    execve(child->script_, child->argv_, child->evp_);
+        // if execve returns, an error occurred, but logging doesn't work
+        // because we closed all file descriptors, so just write errno to
+        // pipe and call exit
+    int len = write(pipefd[1], (void*)(&errno), sizeof(errno));
+    if(len) exit(-1);
+    exit(-1);
+  }
+  close(pipefd[1]);
+
+  child->pid_ = pid;
+  child->err_fd_ = pipefd[0];
+
+  log_printf(INFO, "called script '%s' with pid %d", child->script_, child->pid_);
+
+  return child;
+}
+
+int sydra_waitpid(child_t* child, int* status_return)
+{
+  int status = 0;
+  pid_t pid = waitpid(child->pid_, &status, WNOHANG);
+  if(!pid || (pid < 0 && errno == ECHILD))
+    return 0;
+  if(pid < 0) {
+    log_printf(ERROR, "waitpid returned with error: %s", strerror(errno)); // TODO: thread safe strerror
+    return pid;
+  }
+
+  fd_set rfds;
+  FD_ZERO(&rfds);
+  FD_SET(child->err_fd_, &rfds);
+  struct timeval tv = { 0 , 0 };
+  if(select(child->err_fd_+1, &rfds, NULL, NULL, &tv) == 1) {
+    int err = 0;
+    if(read(child->err_fd_, (void*)(&err), sizeof(err)) >= sizeof(err)) {
+      log_printf(INFO, "script '%s' exec() error: %s", child->script_, strerror(err)); // TODO: thread safe strerror
+      return -1;
+    }
+  }
+  if(WIFEXITED(status))
+    log_printf(INFO, "script '%s' (pid %d) returned %d", child->script_, child->pid_, WEXITSTATUS(status));
+  else if(WIFSIGNALED(status))
+    log_printf(INFO, "script '%s' (pid %d) terminated after signal %d", child->script_, child->pid_, WTERMSIG(status));
+  else
+    log_printf(INFO, "executing script '%s' (pid %d): unkown error", child->script_, child->pid_);
+
+  if(status_return) *status_return = status;
+
+  return 1;
+}
diff --git a/src/sysexec.h b/src/sysexec.h
new file mode 100644
index 0000000..dc00bb6
--- /dev/null
+++ b/src/sysexec.h
@@ -0,0 +1,51 @@
+/*
+ *  sydra
+ *
+ *  sydra is a toolbox which allows you to set up multiple bidirectional
+ *  Video/Audio streams from external locations.
+ *  sydra has been written to be used for the Elevate Festival in Graz
+ *  Austria in order to involve external locations to present themselves
+ *  at the festival.
+ *  Sydra is based on GStreamer and is written in C.
+ *
+ *
+ *  Copyright (C) 2014 Christian Pointner <equinox@helsinki.at>
+ *
+ *  This file is part of sydra.
+ *
+ *  sydra 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
+ *  any later version.
+ *
+ *  sydra 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 sydra. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef SYDRA_sysexec_h_INCLUDED
+#define SYDRA_sysexec_h_INCLUDED
+
+#include <sys/types.h>
+#include "options.h"
+
+struct child_struct {
+  pid_t pid_;
+  char* script_;
+  int err_fd_;
+  char** argv_;
+  char** evp_;
+};
+typedef struct child_struct child_t;
+
+child_t* new_child(const char* script, char* const argv[], char* const evp[]);
+void free_child(child_t* child);
+
+child_t* sydra_exec(const char* script, char* const argv[], char* const evp[]);
+int sydra_waitpid(child_t* child, int* status);
+
+#endif
diff --git a/src/writer.c b/src/writer.c
new file mode 100644
index 0000000..f282f8d
--- /dev/null
+++ b/src/writer.c
@@ -0,0 +1,243 @@
+/*
+ *  sydra
+ *
+ *  sydra is a toolbox which allows you to set up multiple bidirectional
+ *  Video/Audio streams from external locations.
+ *  sydra has been written to be used for the Elevate Festival in Graz
+ *  Austria in order to involve external locations to present themselves
+ *  at the festival.
+ *  Sydra is based on GStreamer and is written in C.
+ *
+ *
+ *  Copyright (C) 2014 Christian Pointner <equinox@helsinki.at>
+ *
+ *  This file is part of sydra.
+ *
+ *  sydra 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
+ *  any later version.
+ *
+ *  sydra 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 sydra. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <gst/gst.h>
+
+#include <sys/types.h>
+
+#include <errno.h>
+#include <string.h>
+#include <time.h>
+
+#include "writer.h"
+
+#include "datatypes.h"
+#include "log.h"
+#include "file_list.h"
+
+static int init_time_boundaries(writer_t* writer)
+{
+  if(!writer)
+    return -1;
+
+  struct timespec now;
+  clock_gettime(CLOCK_REALTIME, &now);
+
+  struct tm bd_time;
+  localtime_r(&(now.tv_sec), &bd_time);
+
+  writer->current_ = file_list_add(&(writer->files_), &bd_time, "current", writer->name_format_, writer->output_dir_, writer->mode_, writer->nocache_);
+  if(writer->current_ == NULL) return -2;
+
+  bd_time.tm_sec = 0;
+  bd_time.tm_min = 0;
+  time_t T = mktime(&bd_time);
+  T+=3600;
+  localtime_r(&T, &bd_time);
+
+  struct timespec b = { T, 0 };
+  writer->next_boundary_ = b;
+
+  writer->next_ = file_list_add(&(writer->files_), &bd_time, "next", writer->name_format_, writer->output_dir_, writer->mode_, writer->nocache_);
+  if(writer->next_ == NULL) return -2;
+
+  return 0;
+}
+
+static void added_cb(GstElement* sink, gint fd, gpointer data)
+{
+  gint num_fds;
+  g_object_get(G_OBJECT(sink), "num_fds", &num_fds, NULL);
+  log_printf(INFO, "fdsink: successfully added client %d (sink has now %d fds)", fd, num_fds);
+}
+
+static void removed_cb(GstElement* sink, gint fd, gpointer data)
+{
+  gint num_fds;
+  g_object_get(G_OBJECT(sink), "num_fds", &num_fds, NULL);
+  log_printf(INFO, "fdsink: successfully removed client %d (sink has now %d fds)", fd, num_fds);
+}
+
+static void fdremoved_cb(GstElement* sink, gint fd, gpointer data)
+{
+  gint num_fds;
+  g_object_get(G_OBJECT(sink), "num_fds", &num_fds, NULL);
+  log_printf(INFO, "fdsink: successfully removed fd %d (sink has now %d fds)", fd, num_fds);
+
+  writer_t *writer = (writer_t*)data;
+  if(writer->post_process_)
+    file_list_call_post_process(&(writer->files_), fd, writer->post_process_);
+  else
+    file_list_remove(&(writer->files_), fd);
+}
+
+int writer_init(writer_t* writer, GMainLoop *loop, const char* name_format, mode_t mode, int nocache, const char* output_dir, int interval, int offset, char* post_process)
+{
+  if(!writer)
+    return -1;
+
+  writer->loop_ = loop;
+  writer->sink_ = gst_element_factory_make("multifdsink", "writer");
+  if(!writer->sink_) {
+    log_printf(ERROR, "the writer object could not be created. Exiting.");
+    return -1;
+  }
+      // TODO: how the heck should we get the right value? 3 means keyframe...
+  g_object_set(G_OBJECT(writer->sink_), "recover-policy", 3, NULL);
+  g_signal_connect(G_OBJECT(writer->sink_), "client-added", G_CALLBACK(added_cb), writer);
+  g_signal_connect(G_OBJECT(writer->sink_), "client-removed", G_CALLBACK(removed_cb), writer);
+  g_signal_connect(G_OBJECT(writer->sink_), "client-fd-removed", G_CALLBACK(fdremoved_cb), writer);
+
+  writer->clock_ = gst_system_clock_obtain();
+  if(!writer->clock_) {
+    log_printf(ERROR, "unable to obtain the system clock");
+    return -1;
+  }
+  writer->name_format_ = name_format;
+  writer->mode_ = mode;
+  writer->nocache_ = nocache;
+  writer->output_dir_ = output_dir;
+  writer->interval_ = interval * GST_MSECOND;
+  writer->offset_ = offset * GST_MSECOND;
+  writer->post_process_ = post_process;
+  writer->clock_id_ = NULL;
+  writer->thread_ = NULL;
+  int ret = file_list_init(&(writer->files_));
+  if(ret) return ret;
+
+  return init_time_boundaries(writer);
+}
+
+static void add_fd(writer_t* writer, int fd)
+{
+  log_printf(INFO, "adding fd %d to fdsink", fd);
+  g_signal_emit_by_name(G_OBJECT(writer->sink_), "add", fd, NULL);
+}
+
+static void remove_fd(writer_t* writer, int fd)
+{
+  log_printf(INFO, "removing fd %d from fdsink", fd);
+  g_signal_emit_by_name(G_OBJECT(writer->sink_), "remove-flush", fd, NULL);
+}
+
+static int check_boundaries(writer_t* writer)
+{
+  struct timespec now;
+  clock_gettime(CLOCK_REALTIME, &now);
+
+  GstClockTime tmp = GST_TIMESPEC_TO_TIME(now);
+  GstClockTime boundary = GST_TIMESPEC_TO_TIME(writer->next_boundary_);
+  tmp -= writer->offset_;
+  if(tmp >= boundary) {
+    struct tm now_bd;
+    localtime_r(&(now.tv_sec), &now_bd);
+    log_printf(INFO, "boundary reached! it's now: %02d:%02d:%02d.%06d on %d.%d.%d%s (%d ms offset)", now_bd.tm_hour, now_bd.tm_min, now_bd.tm_sec, now.tv_nsec/1000, now_bd.tm_mday, now_bd.tm_mon+1, now_bd.tm_year+1900, now_bd.tm_isdst > 0 ? " (DST)": "", GST_TIME_AS_MSECONDS(writer->offset_));
+
+    int ret = open_file(writer->next_);
+    if(ret) return ret; // TODO: stop writer on open_file error ???
+
+    add_fd(writer, writer->next_->fd_);
+    remove_fd(writer, writer->current_->fd_);
+    writer->current_ = writer->next_;
+
+    writer->next_boundary_.tv_sec += 3600;
+    struct tm bd_time;
+    localtime_r(&(writer->next_boundary_.tv_sec), &bd_time);
+
+    writer->next_ = file_list_add(&(writer->files_), &bd_time, "next", writer->name_format_, writer->output_dir_, writer->mode_, writer->nocache_);
+    if(writer->next_ == NULL) return -2;
+  }
+
+  return 0;
+}
+
+static gpointer writer_thread_func(gpointer data)
+{
+  writer_t *writer = (writer_t*)data;
+  log_printf(NOTICE, "writer thread started");
+
+  for(;;) {
+    GstClockReturn wret =  gst_clock_id_wait(writer->clock_id_, NULL);
+    if(GST_CLOCK_UNSCHEDULED == wret)
+      break;
+    if(GST_CLOCK_EARLY == wret)
+      continue;
+
+    int ret = check_boundaries(writer);
+    if(ret) break;
+
+    ret = file_list_waitpid(&(writer->files_));
+    if(ret) break;
+  }
+
+  log_printf(NOTICE, "writer thread stopped");
+  g_main_loop_quit(writer->loop_);
+  return NULL;
+}
+
+int writer_start(writer_t* writer)
+{
+  if(!writer)
+    return -1;
+
+  int ret = open_file(writer->current_);
+  if(ret)
+    return ret;
+
+  add_fd(writer, writer->current_->fd_);
+
+  writer->clock_id_ = gst_clock_new_periodic_id(writer->clock_, 0, writer->interval_);
+  if(!writer->clock_id_) {
+    log_printf(ERROR, "clock id could not be created");
+    return -1;
+  }
+  writer->thread_ = g_thread_new("writer", writer_thread_func, writer);
+  if(!writer->thread_) {
+    log_printf(ERROR, "writer thread could not be started");
+    return -1;
+  }
+
+  return 0;
+}
+
+void writer_stop(writer_t* writer)
+{
+  if(!writer)
+    return;
+
+  file_list_clear(&(writer->files_));
+  if(writer->clock_id_) {
+    gst_clock_id_unschedule(writer->clock_id_);
+  }
+  if(writer->thread_) {
+    log_printf(NOTICE, "waiting for writer thread to stop");
+    g_thread_join(writer->thread_);
+  }
+  gst_object_unref(GST_OBJECT(writer->clock_));
+}
diff --git a/src/writer.h b/src/writer.h
new file mode 100644
index 0000000..99993db
--- /dev/null
+++ b/src/writer.h
@@ -0,0 +1,64 @@
+/*
+ *  sydra
+ *
+ *  sydra is a toolbox which allows you to set up multiple bidirectional
+ *  Video/Audio streams from external locations.
+ *  sydra has been written to be used for the Elevate Festival in Graz
+ *  Austria in order to involve external locations to present themselves
+ *  at the festival.
+ *  Sydra is based on GStreamer and is written in C.
+ *
+ *
+ *  Copyright (C) 2014 Christian Pointner <equinox@helsinki.at>
+ *
+ *  This file is part of sydra.
+ *
+ *  sydra 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
+ *  any later version.
+ *
+ *  sydra 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 sydra. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef SYDRA_writer_h_INCLUDED
+#define SYDRA_writer_h_INCLUDED
+
+#include <gst/gst.h>
+#include <glib.h>
+#include <time.h>
+#include <sys/types.h>
+
+#include "file_list.h"
+
+struct writer_struct {
+  GMainLoop *loop_;
+  GstElement* sink_;
+  GstClock* clock_;
+  GstClockID clock_id_;
+  GThread* thread_;
+  const char* name_format_;
+  const char* output_dir_;
+  mode_t mode_;
+  int nocache_;
+  GstClockTime interval_;
+  GstClockTime offset_;
+  char* post_process_;
+  file_list_t files_;
+  file_t* current_;
+  file_t* next_;
+  struct timespec next_boundary_;
+};
+typedef struct writer_struct writer_t;
+
+int writer_init(writer_t* writer, GMainLoop *loop, const char* name_format, mode_t mode, int nocache, const char* output_dir, int interval, int offset, char* post_process);
+int writer_start(writer_t* writer);
+void writer_stop(writer_t* writer);
+
+#endif
-- 
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