system: use signalfd for dlt-system

1: Move the call of pthread_sigmask in dlt-qnx-systems main before DLT_REGISTER_APP, because this already spawns a thread, what was done without applying pthread_sigmask before.
2: Replaced all threads in dlt-system, that are spawned for each feature, through one poll. This poll waits for a file descriptor event, that triggers the feature routine, that was executed before in the thread. Done this for following processes:

* reading syslog and journal
* frequently reading logfile and logprocess
* triggering filetransfer, if a file was added/changed in watched directory
* checking watchdog timer of systemd service file with defined intervall

Signed-off-by: dbiastoch <dbiastoch@de.adit-jv.com>

13 files changed, 512 insertions, 496 deletions

diff --git a/doc/dlt-system.conf.5.md b/doc/dlt-system.conf.5.md
index 7020281..9fc65b2 100644
--- a/doc/dlt-system.conf.5.md
+++ b/doc/dlt-system.conf.5.md
@@ -114,12 +114,6 @@ Time in seconds after startup of dlt-system when first file is transfered.
 
     Default: 0
 
-## FiletransferTimeDelay
-
-Time in seconds to wait between deletion of transferred file and start of next file transfer.
-
-    Default: 10
-
 ## FiletransferTimeoutBetweenLogs
 
 Time in seconds to wait between two file transfer logs of a single file to DLT.
diff --git a/src/dlt-qnx-system/dlt-qnx-system.c b/src/dlt-qnx-system/dlt-qnx-system.c
index afd34b4..03ad0fb 100644
--- a/src/dlt-qnx-system/dlt-qnx-system.c
+++ b/src/dlt-qnx-system/dlt-qnx-system.c
@@ -70,28 +70,27 @@ int main(int argc, char* argv[])
         daemonize();
     }
 
-    DLT_REGISTER_APP(config.applicationId, "DLT QNX System");
-    DLT_REGISTER_CONTEXT(dltQnxSystem, config.applicationContextId,
-            "Context of main dlt qnx system manager");
-
-    DLT_LOG(dltQnxSystem, DLT_LOG_DEBUG,
-            DLT_STRING("Setting signals wait for abnormal exit"));
-
-    g_threads.mainThread = pthread_self();
-
     sigemptyset(&mask);
     sigaddset(&mask, SIGTERM);
     sigaddset(&mask, SIGHUP);
     sigaddset(&mask, SIGQUIT);
     sigaddset(&mask, SIGINT);
     sigaddset(&mask, SIGALRM);
-    if (pthread_sigmask(SIG_BLOCK, &mask, NULL) == -1) {
-        DLT_LOG(dltQnxSystem, DLT_LOG_WARN,
-                DLT_STRING("Failed to block signals!"));
-        DLT_UNREGISTER_APP();
+    if (pthread_sigmask(SIG_BLOCK, &mask, NULL) != 0)
+    {
+        fprintf(stderr, "Couldn't set mask for potential future threads.\n");
         return -1;
     }
 
+    DLT_REGISTER_APP(config.applicationId, "DLT QNX System");
+    DLT_REGISTER_CONTEXT(dltQnxSystem, config.applicationContextId,
+            "Context of main dlt qnx system manager");
+
+    DLT_LOG(dltQnxSystem, DLT_LOG_DEBUG,
+            DLT_STRING("Setting signals wait for abnormal exit"));
+
+    g_threads.mainThread = pthread_self();
+
     DLT_LOG(dltQnxSystem, DLT_LOG_DEBUG, DLT_STRING("Launching threads."));
     start_threads(&config);
 
diff --git a/src/system/dlt-system-filetransfer.c b/src/system/dlt-system-filetransfer.c
index dbc5431..a06e512 100644
--- a/src/system/dlt-system-filetransfer.c
+++ b/src/system/dlt-system-filetransfer.c
@@ -49,7 +49,6 @@
 *******************************************************************************/
 
 
-#include <pthread.h>
 #include <unistd.h>
 #ifdef linux
 #   include <sys/inotify.h>
@@ -61,6 +60,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <inttypes.h>
+#include <poll.h>
 
 #include "dlt-system.h"
 #include "dlt.h"
@@ -76,8 +76,6 @@
 #define SUBDIR_TOSEND ".tosend"
 
 
-
-extern DltSystemThreads threads;
 /* From dlt_filetransfer */
 extern uint32_t getFileSerialNumber(const char *file, int *ok);
 
@@ -85,11 +83,6 @@ DLT_IMPORT_CONTEXT(dltsystem)
 DLT_DECLARE_CONTEXT(filetransferContext)
 
 #ifdef linux
-typedef struct {
-    int handle;
-    int fd[DLT_SYSTEM_LOG_DIRS_MAX];
-} s_ft_inotify;
-
 s_ft_inotify ino;
 #endif
 
@@ -260,7 +253,6 @@ int send_one(char *src, FiletransferOptions const *opts, int which)
 {
     DLT_LOG(dltsystem, DLT_LOG_DEBUG,
             DLT_STRING("dlt-system-filetransfer, sending a file."));
-    sleep(opts->TimeDelay);
 
     /* Prepare all needed file names */
     char *fn = basename(src);
@@ -374,7 +366,6 @@ int send_one(char *src, FiletransferOptions const *opts, int which)
 
 int flush_dir_send(FiletransferOptions const *opts, const char *compress_dir, const char *send_dir)
 {
-
     struct dirent *dp;
     DIR *dir;
     dir = opendir(send_dir);
@@ -568,8 +559,6 @@ int flush_dir_original(FiletransferOptions const *opts, int which)
  */
 int flush_dir(FiletransferOptions const *opts, int which)
 {
-
-
     DLT_LOG(dltsystem, DLT_LOG_DEBUG,
             DLT_STRING("dlt-system-filetransfer, flush directory of old files."));
 
@@ -611,11 +600,13 @@ int flush_dir(FiletransferOptions const *opts, int which)
 
 /*!Initializes the surveyed directories */
 /**On startup, the inotifiy handlers are created, and existing files shall be sent into DLT stream
- * @param opts FiletransferOptions
+ * @param config DltSystemConfiguration
  * @return Returns 0 if everything was okay. If there was a failure a value < 0 will be returned.
  */
-int init_filetransfer_dirs(FiletransferOptions const *opts)
+int init_filetransfer_dirs(DltSystemConfiguration *config)
 {
+    FiletransferOptions const *opts = &(config->Filetransfer);
+    DLT_REGISTER_CONTEXT(filetransferContext, config->Filetransfer.ContextId, "Filetransfer Adapter");
     DLT_LOG(dltsystem, DLT_LOG_DEBUG,
             DLT_STRING("dlt-system-filetransfer, initializing inotify on directories."));
     int i;
@@ -690,20 +681,19 @@ int init_filetransfer_dirs(FiletransferOptions const *opts)
         flush_dir(opts, i);
 
     }
-
     return 0;
 }
 
-int wait_for_files(FiletransferOptions const *opts)
+int process_files(FiletransferOptions const *opts)
 {
 #ifdef linux
-    DLT_LOG(dltsystem, DLT_LOG_DEBUG, DLT_STRING("dlt-system-filetransfer, waiting for files."));
+    DLT_LOG(dltsystem, DLT_LOG_DEBUG, DLT_STRING("dlt-system-filetransfer, processing files."));
     static char buf[INOTIFY_LEN];
     ssize_t len = read(ino.handle, buf, INOTIFY_LEN);
 
     if (len < 0) {
         DLT_LOG(filetransferContext, DLT_LOG_ERROR,
-                DLT_STRING("Error while waiting for files in dlt-system file transfer."));
+                DLT_STRING("Error while reading events for files in dlt-system file transfer."));
         return -1;
     }
 
@@ -748,24 +738,7 @@ int wait_for_files(FiletransferOptions const *opts)
     return 0;
 }
 
-void filetransfer_thread(void *v_conf)
+void filetransfer_fd_handler(DltSystemConfiguration *config)
 {
-    DLT_LOG(dltsystem, DLT_LOG_DEBUG, DLT_STRING("dlt-system-filetransfer, in thread."));
-    DltSystemConfiguration *conf = (DltSystemConfiguration *)v_conf;
-    DLT_REGISTER_CONTEXT(filetransferContext, conf->Filetransfer.ContextId,
-                         "File transfer manager.");
-
-    sleep(conf->Filetransfer.TimeStartup);
-
-    if (init_filetransfer_dirs(&(conf->Filetransfer)) < 0)
-        return;
-
-    while (!threads.shutdown) {
-        if (wait_for_files(&(conf->Filetransfer)) < 0) {
-            DLT_LOG(dltsystem, DLT_LOG_ERROR, DLT_STRING("Error while waiting files. File transfer shutdown."));
-            return;
-        }
-
-        sleep(conf->Filetransfer.TimeDelay);
-    }
-}
+    process_files(&(config->Filetransfer));
+}
\ No newline at end of file
diff --git a/src/system/dlt-system-journal.c b/src/system/dlt-system-journal.c
index aa9ba52..c56e58a 100644
--- a/src/system/dlt-system-journal.c
+++ b/src/system/dlt-system-journal.c
@@ -43,7 +43,7 @@
 *******************************************************************************/
 #if defined(DLT_SYSTEMD_JOURNAL_ENABLE)
 
-#include <pthread.h>
+#include <poll.h>
 #include <unistd.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
@@ -56,7 +56,6 @@
 #include <systemd/sd-id128.h>
 #include <inttypes.h> /* for PRI formatting macro */
 
-extern DltSystemThreads threads;
 
 #define DLT_SYSTEM_JOURNAL_BUFFER_SIZE 256
 #define DLT_SYSTEM_JOURNAL_BUFFER_SIZE_BIG 2048
@@ -199,13 +198,10 @@ void dlt_system_journal_get_timestamp(sd_journal *journal, MessageTimestamp *tim
              time_usecs % 1000000);
 }
 
-void journal_thread(void *v_conf)
-{
-    int r;
-    sd_journal *j;
-    char match[DLT_SYSTEM_JOURNAL_BOOT_ID_MAX_LENGTH] = "_BOOT_ID=";
-    sd_id128_t boot_id;
+void get_journal_msg(sd_journal *j, DltSystemConfiguration *config) 
+{   
     uint32_t ts;
+    int r;
 
     char buffer_process[DLT_SYSTEM_JOURNAL_BUFFER_SIZE] = { 0 },
          buffer_priority[DLT_SYSTEM_JOURNAL_BUFFER_SIZE] = { 0 },
@@ -220,183 +216,178 @@ void journal_thread(void *v_conf)
     char *systemd_log_levels[] =
     { "Emergency", "Alert", "Critical", "Error", "Warning", "Notice", "Informational", "Debug" };
 
-    DLT_LOG(dltsystem, DLT_LOG_DEBUG,
-            DLT_STRING("dlt-system-journal, in thread."));
+    for(;;)
+    {
+        r = sd_journal_next(j);
+        if (r < 0) {
+            DLT_LOG(dltsystem, DLT_LOG_ERROR,
+                    DLT_STRING("dlt-system-journal failed to get next entry:"), DLT_STRING(strerror(-r)));
+            sd_journal_close(j);
+            return;
+        }
+        else if (r == 0) {
+            return;
+        }
 
-    DltSystemConfiguration *conf = (DltSystemConfiguration *)v_conf;
-    DLT_REGISTER_CONTEXT(journalContext, conf->Journal.ContextId, "Journal Adapter");
+        /* get all data from current journal entry */
+        dlt_system_journal_get_timestamp(j, &timestamp);
+
+        /* get data from journal entry, empty string if invalid fields */
+        dlt_system_journal_get(j, buffer_comm, "_COMM", sizeof(buffer_comm));
+        dlt_system_journal_get(j, buffer_pid, "_PID", sizeof(buffer_pid));
+        dlt_system_journal_get(j, buffer_priority, "PRIORITY", sizeof(buffer_priority));
+        dlt_system_journal_get(j, buffer_message, "MESSAGE", sizeof(buffer_message));
+        dlt_system_journal_get(j, buffer_transport, "_TRANSPORT", sizeof(buffer_transport));
+
+        /* prepare process string */
+        if (strcmp(buffer_transport, "kernel") == 0)
+            snprintf(buffer_process, DLT_SYSTEM_JOURNAL_BUFFER_SIZE, "kernel:");
+        else
+            snprintf(buffer_process, DLT_SYSTEM_JOURNAL_BUFFER_SIZE, "%s[%s]:", buffer_comm, buffer_pid);
+
+        /* map log level on demand */
+        loglevel = DLT_LOG_INFO;
+        systemd_loglevel = atoi(buffer_priority);
+
+        if (config->Journal.MapLogLevels) {
+            /* Map log levels from journal to DLT */
+            switch (systemd_loglevel) {
+            case 0:     /* Emergency */
+            case 1:     /* Alert */
+            case 2:     /* Critical */
+                loglevel = DLT_LOG_FATAL;
+                break;
+            case 3:     /* Error */
+                loglevel = DLT_LOG_ERROR;
+                break;
+            case 4:     /* Warning */
+                loglevel = DLT_LOG_WARN;
+                break;
+            case 5:     /* Notice */
+            case 6:     /* Informational */
+                loglevel = DLT_LOG_INFO;
+                break;
+            case 7:     /* Debug */
+                loglevel = DLT_LOG_DEBUG;
+                break;
+            default:
+                loglevel = DLT_LOG_INFO;
+                break;
+            }
+        }
 
-    r = sd_journal_open(&j, SD_JOURNAL_LOCAL_ONLY /*SD_JOURNAL_LOCAL_ONLY|SD_JOURNAL_RUNTIME_ONLY*/);
-    printf("journal open return %d\n", r);
+        if ((systemd_loglevel >= 0) && (systemd_loglevel <= 7))
+            snprintf(buffer_priority, DLT_SYSTEM_JOURNAL_BUFFER_SIZE, "%s:", systemd_log_levels[systemd_loglevel]);
+        else
+            snprintf(buffer_priority, DLT_SYSTEM_JOURNAL_BUFFER_SIZE, "prio_unknown:");
+
+        /* write log entry */
+        if (config->Journal.UseOriginalTimestamp == 0) {
+            DLT_LOG(journalContext, loglevel,
+                    DLT_STRING(timestamp.real),
+                    DLT_STRING(timestamp.monotonic),
+                    DLT_STRING(buffer_process),
+                    DLT_STRING(buffer_priority),
+                    DLT_STRING(buffer_message)
+                    );
 
+        }
+        else {
+            /* since we are talking about points in time, I'd prefer truncating over arithmetic rounding */
+            ts = (uint32_t)(atof(timestamp.monotonic) * 10000);
+            DLT_LOG_TS(journalContext, loglevel, ts,
+                        DLT_STRING(timestamp.real),
+                        DLT_STRING(buffer_process),
+                        DLT_STRING(buffer_priority),
+                        DLT_STRING(buffer_message)
+                        );
+        }
+
+        if (journal_checkUserBufferForFreeSpace() == -1) {
+            /* buffer is nearly full */
+            /* wait 500ms for writing next entry */
+            struct timespec t;
+            t.tv_sec = 0;
+            t.tv_nsec = 1000000ul * 500;
+            nanosleep(&t, NULL);
+        }
+    }
+}
+
+void register_journal_fd(sd_journal **j, struct pollfd *pollfd, int i,  DltSystemConfiguration *config)
+{
+    DLT_REGISTER_CONTEXT(journalContext, config->Journal.ContextId, "Journal Adapter");
+    sd_journal *j_tmp;
+    char match[DLT_SYSTEM_JOURNAL_BOOT_ID_MAX_LENGTH] = "_BOOT_ID=";
+    sd_id128_t boot_id;
+    int r;
+
+    r = sd_journal_open(&j_tmp, SD_JOURNAL_LOCAL_ONLY /*SD_JOURNAL_LOCAL_ONLY|SD_JOURNAL_RUNTIME_ONLY*/);
+    printf("journal open return %d\n", r);
     if (r < 0) {
         DLT_LOG(dltsystem, DLT_LOG_ERROR,
                 DLT_STRING("dlt-system-journal, cannot open journal:"), DLT_STRING(strerror(-r)));
         printf("journal open failed: %s\n", strerror(-r));
-        return;
+        j_tmp = NULL;
     }
 
-    if (conf->Journal.CurrentBoot) {
+    if (config->Journal.CurrentBoot) {
         /* show only current boot entries */
         r = sd_id128_get_boot(&boot_id);
-
         if (r < 0) {
             DLT_LOG(dltsystem, DLT_LOG_ERROR,
                     DLT_STRING("dlt-system-journal failed to get boot id:"), DLT_STRING(strerror(-r)));
-            sd_journal_close(j);
-            return;
-
+            sd_journal_close(j_tmp);
+            j_tmp = NULL;
         }
 
         sd_id128_to_string(boot_id, match + 9);
-        r = sd_journal_add_match(j, match, strlen(match));
-
+        r = sd_journal_add_match(j_tmp, match, strlen(match));
         if (r < 0) {
             DLT_LOG(dltsystem, DLT_LOG_ERROR,
                     DLT_STRING("dlt-system-journal failed to get match:"), DLT_STRING(strerror(-r)));
-            sd_journal_close(j);
-            return;
-
+            sd_journal_close(j_tmp);
+            j_tmp = NULL;
         }
     }
 
-    if (conf->Journal.Follow) {
+    if (config->Journal.Follow) {
         /* show only last 10 entries and follow */
-        r = sd_journal_seek_tail(j);
-
+        r = sd_journal_seek_tail(j_tmp);
         if (r < 0) {
             DLT_LOG(dltsystem, DLT_LOG_ERROR,
                     DLT_STRING("dlt-system-journal failed to seek to tail:"), DLT_STRING(strerror(-r)));
-            sd_journal_close(j);
-            return;
-
+            sd_journal_close(j_tmp);
+            j_tmp = NULL;
         }
 
-        r = sd_journal_previous_skip(j, 10);
-
+        r = sd_journal_previous_skip(j_tmp, 10);
         if (r < 0) {
             DLT_LOG(dltsystem, DLT_LOG_ERROR,
                     DLT_STRING("dlt-system-journal failed to seek back 10 entries:"), DLT_STRING(strerror(-r)));
-            sd_journal_close(j);
-            return;
-
+            sd_journal_close(j_tmp);
+            j_tmp = NULL;
         }
     }
 
-    while (!threads.shutdown) {
-
-        r = sd_journal_next(j);
-
-        if (r < 0) {
-            DLT_LOG(dltsystem, DLT_LOG_ERROR,
-                    DLT_STRING("dlt-system-journal failed to get next entry:"), DLT_STRING(strerror(-r)));
-            sd_journal_close(j);
-            return;
-
-        }
-        else if (r > 0)
-        {
-            /* get all data from current journal entry */
-            dlt_system_journal_get_timestamp(j, &timestamp);
-
-            /* get data from journal entry, empty string if invalid fields */
-            dlt_system_journal_get(j, buffer_comm, "_COMM", sizeof(buffer_comm));
-            dlt_system_journal_get(j, buffer_pid, "_PID", sizeof(buffer_pid));
-            dlt_system_journal_get(j, buffer_priority, "PRIORITY", sizeof(buffer_priority));
-            dlt_system_journal_get(j, buffer_message, "MESSAGE", sizeof(buffer_message));
-            dlt_system_journal_get(j, buffer_transport, "_TRANSPORT", sizeof(buffer_transport));
-
-            /* prepare process string */
-            if (strcmp(buffer_transport, "kernel") == 0)
-                snprintf(buffer_process, DLT_SYSTEM_JOURNAL_BUFFER_SIZE, "kernel:");
-            else
-                snprintf(buffer_process, DLT_SYSTEM_JOURNAL_BUFFER_SIZE, "%s[%s]:", buffer_comm, buffer_pid);
-
-            /* map log level on demand */
-            loglevel = DLT_LOG_INFO;
-            systemd_loglevel = atoi(buffer_priority);
-
-            if (conf->Journal.MapLogLevels) {
-                /* Map log levels from journal to DLT */
-                switch (systemd_loglevel) {
-                case 0:     /* Emergency */
-                case 1:     /* Alert */
-                case 2:     /* Critical */
-                    loglevel = DLT_LOG_FATAL;
-                    break;
-                case 3:     /* Error */
-                    loglevel = DLT_LOG_ERROR;
-                    break;
-                case 4:     /* Warning */
-                    loglevel = DLT_LOG_WARN;
-                    break;
-                case 5:     /* Notice */
-                case 6:     /* Informational */
-                    loglevel = DLT_LOG_INFO;
-                    break;
-                case 7:     /* Debug */
-                    loglevel = DLT_LOG_DEBUG;
-                    break;
-                default:
-                    loglevel = DLT_LOG_INFO;
-                    break;
-                }
-            }
-
-            if ((systemd_loglevel >= 0) && (systemd_loglevel <= 7))
-                snprintf(buffer_priority, DLT_SYSTEM_JOURNAL_BUFFER_SIZE, "%s:", systemd_log_levels[systemd_loglevel]);
-            else
-                snprintf(buffer_priority, DLT_SYSTEM_JOURNAL_BUFFER_SIZE, "prio_unknown:");
-
-            /* write log entry */
-            if (conf->Journal.UseOriginalTimestamp == 0) {
-                DLT_LOG(journalContext, loglevel,
-                        DLT_STRING(timestamp.real),
-                        DLT_STRING(timestamp.monotonic),
-                        DLT_STRING(buffer_process),
-                        DLT_STRING(buffer_priority),
-                        DLT_STRING(buffer_message)
-                        );
-
-            }
-            else {
-                /* since we are talking about points in time, I'd prefer truncating over arithmetic rounding */
-                ts = (uint32_t)(atof(timestamp.monotonic) * 10000);
-                DLT_LOG_TS(journalContext, loglevel, ts,
-                           DLT_STRING(timestamp.real),
-                           DLT_STRING(buffer_process),
-                           DLT_STRING(buffer_priority),
-                           DLT_STRING(buffer_message)
-                           );
-            }
-        }
-        else {
-            r = sd_journal_wait(j, 1000000);
-
-            if (r < 0) {
-                DLT_LOG(dltsystem, DLT_LOG_ERROR,
-                        DLT_STRING("dlt-system-journal failed to call sd_journal_get_realtime_usec(): "),
-                        DLT_STRING(strerror(-r)));
-                sd_journal_close(j);
-                return;
-
-            }
-        }
-
-        if (journal_checkUserBufferForFreeSpace() == -1) {
-            /* buffer is nearly full */
-            /* wait 500ms for writing next entry */
-            struct timespec t;
-            t.tv_sec = 0;
-            t.tv_nsec = 1000000ul * 500;
-            nanosleep(&t, NULL);
-        }
+    pollfd[i].fd = sd_journal_get_fd(j_tmp);
+    if(pollfd[i].fd < 0) {
+        DLT_LOG(dltsystem, DLT_LOG_ERROR, DLT_STRING("Error while getting journal fd: "), 
+            DLT_STRING(strerror(pollfd[i].fd)));
+        j_tmp = NULL;
     }
+    pollfd[i].events = sd_journal_get_events(j_tmp);
+    if(pollfd[i].events < 0) {
+        DLT_LOG(dltsystem, DLT_LOG_ERROR, DLT_STRING("Error while getting journal events: "), 
+            DLT_STRING(strerror(pollfd[i].events)));
+        j_tmp = NULL;
+    }
+    *j = j_tmp;
+}
 
-    sd_journal_close(j);
-
-    DLT_UNREGISTER_CONTEXT(journalContext);
-
+void journal_fd_handler(sd_journal *j, DltSystemConfiguration *config)
+{
+    get_journal_msg(j, config);
 }
 
-#endif /* DLT_SYSTEMD_JOURNAL_ENABLE */
+#endif /* DLT_SYSTEMD_JOURNAL_ENABLE */
\ No newline at end of file
diff --git a/src/system/dlt-system-logfile.c b/src/system/dlt-system-logfile.c
index 6466172..5e916d4 100644
--- a/src/system/dlt-system-logfile.c
+++ b/src/system/dlt-system-logfile.c
@@ -44,7 +44,6 @@
 *******************************************************************************/
 
 
-#include <pthread.h>
 #include <unistd.h>
 #include "dlt-system.h"
 
@@ -55,8 +54,8 @@
 
 DLT_IMPORT_CONTEXT(dltsystem)
 
-extern DltSystemThreads threads;
 DltContext logfileContext[DLT_SYSTEM_LOG_FILE_MAX];
+int logfile_delays[DLT_SYSTEM_LOG_FILE_MAX];
 
 void send_file(LogFileOptions const *fileopt, int n)
 {
@@ -108,7 +107,7 @@ void register_contexts(LogFileOptions const *fileopts)
                              (*fileopts).Filename[i]);
 }
 
-void logfile_thread(void *v_conf)
+void logfile_init(void *v_conf)
 {
     DLT_LOG(dltsystem, DLT_LOG_DEBUG,
             DLT_STRING("dlt-system-logfile, in thread."));
@@ -116,29 +115,26 @@ void logfile_thread(void *v_conf)
 
     register_contexts(&(conf->LogFile));
 
-    int logfile_delays[DLT_SYSTEM_LOG_FILE_MAX];
-    int i;
-
-    for (i = 0; i < conf->LogFile.Count; i++)
+    for (int i = 0; i < conf->LogFile.Count; i++)
         logfile_delays[i] = conf->LogFile.TimeDelay[i];
+}
 
-    while (!threads.shutdown) {
-        sleep(1);
-
-        for (i = 0; i < conf->LogFile.Count; i++) {
-            if (conf->LogFile.Mode[i] == SEND_MODE_OFF)
-                continue;
+void logfile_fd_handler(void *v_conf)
+{
+    DltSystemConfiguration *conf = (DltSystemConfiguration *)v_conf;
+    for (int i = 0; i < conf->LogFile.Count; i++) {
+        if (conf->LogFile.Mode[i] == SEND_MODE_OFF)
+            continue;
 
-            if (logfile_delays[i] <= 0) {
-                send_file(&(conf->LogFile), i);
-                logfile_delays[i] = conf->LogFile.TimeDelay[i];
+        if (logfile_delays[i] <= 0) {
+            send_file(&(conf->LogFile), i);
+            logfile_delays[i] = conf->LogFile.TimeDelay[i];
 
-                if (conf->LogFile.Mode[i] == SEND_MODE_ONCE)
-                    conf->LogFile.Mode[i] = SEND_MODE_OFF;
-            }
-            else {
-                logfile_delays[i]--;
-            }
+            if (conf->LogFile.Mode[i] == SEND_MODE_ONCE)
+                conf->LogFile.Mode[i] = SEND_MODE_OFF;
+        }
+        else {
+            logfile_delays[i]--;
         }
     }
 }
diff --git a/src/system/dlt-system-options.c b/src/system/dlt-system-options.c
index 5fa31cb..89a9196 100644
--- a/src/system/dlt-system-options.c
+++ b/src/system/dlt-system-options.c
@@ -153,7 +153,6 @@ void init_configuration(DltSystemConfiguration *config)
     /* File transfer */
     config->Filetransfer.Enable = 0;
     config->Filetransfer.ContextId = "FILE";
-    config->Filetransfer.TimeDelay = 10;
     config->Filetransfer.TimeStartup = 30;
     config->Filetransfer.TimeoutBetweenLogs = 10;
     config->Filetransfer.Count = 0;
@@ -310,10 +309,6 @@ int read_configuration_file(DltSystemConfiguration *config, char *file_name)
             {
                 config->Filetransfer.TimeStartup = atoi(value);
             }
-            else if (strcmp(token, "FiletransferTimeDelay") == 0)
-            {
-                config->Filetransfer.TimeDelay = atoi(value);
-            }
             else if (strcmp(token, "FiletransferTimeoutBetweenLogs") == 0)
             {
                 config->Filetransfer.TimeoutBetweenLogs = atoi(value);
diff --git a/src/system/dlt-system-process-handling.c b/src/system/dlt-system-process-handling.c
index eb310b0..57bd774 100644
--- a/src/system/dlt-system-process-handling.c
+++ b/src/system/dlt-system-process-handling.c
@@ -50,12 +50,26 @@
 #include <fcntl.h>
 #include <signal.h>
 #include <sys/wait.h>
-#include <pthread.h>
 #include <limits.h>
 
-volatile DltSystemThreads threads;
+#include <systemd/sd-journal.h>
+#include <poll.h>
+#include <sys/timerfd.h>
+#include <time.h>
 
 DLT_IMPORT_CONTEXT(dltsystem)
+DLT_IMPORT_CONTEXT(syslogContext)
+DLT_IMPORT_CONTEXT(journalContext)
+DLT_IMPORT_CONTEXT(watchdogContext)
+DLT_IMPORT_CONTEXT(procContext)
+DLT_IMPORT_CONTEXT(filetransferContext)
+extern DltContext logfileContext[DLT_SYSTEM_LOG_FILE_MAX];
+
+volatile uint8_t quit = 0;
+
+#if defined(DLT_FILETRANSFER_ENABLE)
+extern s_ft_inotify ino;
+#endif
 
 int daemonize()
 {
@@ -106,105 +120,195 @@ int daemonize()
     return 0;
 }
 
-void start_threads(DltSystemConfiguration *config)
+/* Unregisters all DLT Contexts and closes all file descriptors */
+void cleanup_processes(struct pollfd *pollfd, sd_journal *j, DltSystemConfiguration *config)
 {
-    DLT_LOG(dltsystem, DLT_LOG_DEBUG,
-            DLT_STRING("dlt-system-process-handling, start threads"));
+    //Syslog cleanup
+    if (config->Syslog.Enable)
+        DLT_UNREGISTER_CONTEXT(syslogContext);
+    
+    //Journal cleanup
+#if defined(DLT_SYSTEMD_JOURNAL_ENABLE)
+    if (config->Journal.Enable)
+        DLT_UNREGISTER_CONTEXT(journalContext);
+    if(j != NULL)
+        sd_journal_close(j);
+#endif
 
-    int i;
-    threads.count = 0;
-    threads.shutdown = 0;
+    //Logfile cleanup 
+    if (config->LogFile.Enable) {
+        for (int i = 0; i < config->LogFile.Count; i++)
+            DLT_UNREGISTER_CONTEXT(logfileContext[i]);
+    }
 
-    for (i = 0; i < MAX_THREADS; i++)
-        threads.threads[i] = 0;
+    //LogProcess cleanup 
+    if (config->LogProcesses.Enable) {
+        DLT_UNREGISTER_CONTEXT(procContext);
+    }
 
+    //Watchdog cleanup
 #if defined(DLT_SYSTEMD_WATCHDOG_ENABLE)
-    start_thread(config, watchdog_thread, "systemd watchdog");
+    DLT_UNREGISTER_CONTEXT(watchdogContext);
 #endif
 
-    if (config->Shell.Enable)
-        init_shell();
-
-    if (config->LogFile.Enable)
-        start_thread(config, logfile_thread, "log file");
-
+    //FileTransfer cleanup
 #if defined(DLT_FILETRANSFER_ENABLE)
-    if (config->Filetransfer.Enable)
-        start_thread(config, filetransfer_thread, "file transfer");
+    if (config->Filetransfer.Enable) {
+        DLT_UNREGISTER_CONTEXT(filetransferContext);
+    }
 #endif
 
-    if (config->LogProcesses.Enable)
-        start_thread(config, logprocess_thread, "log process");
-
-    if (config->Syslog.Enable)
-        start_thread(config, syslog_thread, "syslog");
-
-#if defined(DLT_SYSTEMD_JOURNAL_ENABLE)
-
-    if (config->Journal.Enable)
-        start_thread(config, journal_thread, "systemd journal");
-
-#endif
+    for (int i = 0; i < MAX_FD_NUMBER; i++) {
+        if(pollfd[i].fd > 0)
+            close(pollfd[i].fd);
+    }
 }
 
-/**
- * Start a thread and add it to the thread pool.
- */
-
-void start_thread(DltSystemConfiguration *conf,
-                  void (thread)(void *), const char *name)
+/* Creates timer for LogFile and LogProcess, that need to be called every second. */
+int register_timer_fd(struct pollfd *pollfd, int fdcnt)
 {
-    if (threads.count == MAX_THREADS) {
-        DLT_LOG(dltsystem, DLT_LOG_ERROR,
-                DLT_STRING("Could not create thread for "),
-                DLT_STRING(name),
-                DLT_STRING("Out of thread slots.\n"));
-        return;
+    struct itimerspec timerValue;
+    memset(&timerValue, '\0', sizeof(timerValue));
+    timerValue.it_value.tv_sec = 1;
+    timerValue.it_value.tv_nsec = 0;
+    timerValue.it_interval.tv_sec = 1;
+    timerValue.it_interval.tv_nsec = 0;
+
+    int timerfd = timerfd_create(CLOCK_MONOTONIC, 0);
+    if (timerfd < 0) {
+        DLT_LOG(dltsystem, DLT_LOG_ERROR, DLT_STRING("Failed to create timer fd"));
+        return -1;
     }
+    pollfd[fdcnt].fd = timerfd;
+    pollfd[fdcnt].events = POLLIN;
 
-    DLT_LOG(dltsystem, DLT_LOG_DEBUG, DLT_STRING("Creating thread for "),
-            DLT_STRING(name),
-            DLT_STRING("\n"));
-
-    pthread_t pt;
+    if (timerfd_settime(timerfd, 0, &timerValue, NULL) < 0) {   // init timer with 1 second
+        DLT_LOG(dltsystem, DLT_LOG_ERROR, DLT_STRING("Could not start timer"));
+        return -1;
+    }
+    return 0;
+}
 
-    if (pthread_create(&pt, NULL, (void *)thread, conf) == 0)
-        threads.threads[threads.count++] = pt;
-    else
-        DLT_LOG(dltsystem, DLT_LOG_ERROR,
-                DLT_STRING("Could not create thread for "),
-                DLT_STRING(name),
-                DLT_STRING("\n"));
+/* Routine for executing LogProcess and LogFile, when timer expires */
+void timer_fd_handler(int fd, DltSystemConfiguration *config)
+{
+    long int timersElapsed = 0;
+    int r = read(fd, &timersElapsed, 8);    // only needed to reset fd event
+    if (r < 0) 
+        DLT_LOG(dltsystem, DLT_LOG_ERROR, DLT_STRING("Error while reading timer fd: "), 
+            DLT_STRING(strerror(r)));
+
+    if(config->LogProcesses.Enable)
+        logprocess_fd_handler(config);
+    if(config->LogFile.Enable)
+        logfile_fd_handler(config);
 }
 
-/**
- * Wait for threads to exit.
- * There's not actually a condition currently
- * to bail out of file transfer without a signal.
- */
-void join_threads()
+void start_dlt_system_processes(DltSystemConfiguration *config)
 {
-    int i;
     DLT_LOG(dltsystem, DLT_LOG_DEBUG,
-            DLT_STRING("dlt-system-process-handling, waiting for threads to exit."));
+            DLT_STRING("dlt-system-process-handling, start threads"));
 
-    if (threads.count < 1) {
-        DLT_LOG(dltsystem, DLT_LOG_DEBUG,
-                DLT_STRING("dlt-system-process-handling, no threads, waiting for signal."));
-        sleep(UINT_MAX);
+    if (config->Shell.Enable)
+        init_shell();
+
+    int fdcnt = 0;
+
+    /* Init FDs for all activated processes*/
+    struct pollfd pollfd[MAX_FD_NUMBER];    // Holds all FDs and events
+    uint8_t fdType[MAX_FD_NUMBER];          // Holds corresponding enum for process identification
+
+    for(int cnt = 0 ; cnt < MAX_FD_NUMBER ; cnt++) {
+        pollfd[cnt].fd = 0;
+        pollfd[cnt].events = 0;
     }
-    else {
-        DLT_LOG(dltsystem, DLT_LOG_DEBUG,
-                DLT_STRING("dlt-system-process-handling, thread count: "),
-                DLT_INT(threads.count));
-
-        for (i = 0; i < threads.count; i++) {
-            pthread_join(threads.threads[i], NULL);
-            DLT_LOG(dltsystem, DLT_LOG_DEBUG,
-                    DLT_STRING("dlt-system-process-handling, thread exit: "),
-                    DLT_INT(threads.threads[i]));
+
+    //init FD for LogFile and LogProcesses
+    if (config->LogProcesses.Enable || config->LogFile.Enable) {
+        fdType[fdcnt] = fdType_timer;
+        if (register_timer_fd(pollfd, fdcnt) == 0) {
+            if(config->LogProcesses.Enable)
+                logprocess_init(config);
+            if(config->LogFile.Enable)
+                logfile_init(config);
+            fdcnt++;
         }
     }
+
+    //init FD for Syslog
+    int syslogSock = 0;
+    if (config->Syslog.Enable) {
+        fdType[fdcnt] = fdType_syslog;
+        syslogSock = register_syslog_fd(pollfd, fdcnt, config);
+        fdcnt++;
+    }
+
+    //init FD for Journal
+    sd_journal *j = NULL;
+#if defined(DLT_SYSTEMD_JOURNAL_ENABLE)
+    if (config->Journal.Enable) {
+        register_journal_fd(&j, pollfd, fdcnt, config);
+        fdType[fdcnt] = fdType_journal;
+        fdcnt++;
+    }
+#endif
+
+    //init FD for FileTransfer
+#if defined(DLT_FILETRANSFER_ENABLE)
+    if (config->Filetransfer.Enable) {
+        init_filetransfer_dirs(config);
+        pollfd[fdcnt].fd = ino.handle;
+        pollfd[fdcnt].events = POLLIN;
+        fdType[fdcnt] = fdType_filetransfer;
+        fdcnt++;
+    }
+#endif
+
+    //init FD for Watchdog
+#if defined(DLT_SYSTEMD_WATCHDOG_ENABLE)
+    fdType[fdcnt] = fdType_watchdog;
+    register_watchdog_fd(pollfd, fdcnt);
+#endif
+
+    while (quit == 0)
+    {
+        int ready;
+        ready = poll(pollfd, MAX_FD_NUMBER, -1);
+        if (ready == -1 && quit == 0)
+            DLT_LOG(dltsystem, DLT_LOG_ERROR, DLT_STRING("Error while poll. Exit with: "), 
+                DLT_STRING(strerror(ready)));
+
+        for (int i = 0; i < MAX_FD_NUMBER; i++) {
+            if(pollfd[i].revents & POLLIN){
+                if (fdType[i] == fdType_syslog && syslogSock > 0) {
+                    syslog_fd_handler(syslogSock);
+                }
+                else if (fdType[i] == fdType_timer) {
+                    timer_fd_handler(pollfd[i].fd, config);
+                }
+                #if defined(DLT_SYSTEMD_JOURNAL_ENABLE)
+                else if((fdType[i] == fdType_journal) && (j != NULL)) {
+                    if(sd_journal_process(j) == SD_JOURNAL_APPEND) {
+                        journal_fd_handler(j, config);
+                    }
+                }
+                #endif
+                #if defined(DLT_FILETRANSFER_ENABLE)
+                else if (fdType[i] == fdType_filetransfer) {
+                    filetransfer_fd_handler(config);
+                }
+                #endif
+                #if defined(DLT_SYSTEMD_WATCHDOG_ENABLE)
+                else if (fdType[i] == fdType_watchdog) {
+                    watchdog_fd_handler(pollfd[i].fd);
+                }
+                #endif
+            }
+        }
+    }
+
+    cleanup_processes(pollfd, j, config);
+    exit(0);
 }
 
 void dlt_system_signal_handler(int sig)
@@ -220,12 +324,11 @@ void dlt_system_signal_handler(int sig)
         DLT_LOG(dltsystem, DLT_LOG_DEBUG,
                 DLT_STRING("dlt-system-process-handling, exit, signal: "),
                 DLT_INT(sig));
-        exit(0);
+        quit = 1;
         break;
     default:
         DLT_LOG(dltsystem, DLT_LOG_WARN,
                 DLT_STRING("dlt-system-process-handling, unknown signal!"));
         break;
     }
-}
-
+}
\ No newline at end of file
diff --git a/src/system/dlt-system-processes.c b/src/system/dlt-system-processes.c
index 71f5a1d..a6e4918 100644
--- a/src/system/dlt-system-processes.c
+++ b/src/system/dlt-system-processes.c
@@ -44,7 +44,6 @@
 *******************************************************************************/
 
 
-#include <pthread.h>
 #include <unistd.h>
 #include <ctype.h>
 #include <sys/types.h>
@@ -60,7 +59,7 @@
 #define SEND_MODE_ONCE 1
 #define SEND_MODE_ON   2
 
-extern DltSystemThreads threads;
+int process_delays[DLT_SYSTEM_LOG_PROCESSES_MAX];
 
 DLT_IMPORT_CONTEXT(dltsystem)
 DLT_DECLARE_CONTEXT(procContext)
@@ -125,7 +124,7 @@ void send_process(LogProcessOptions const *popts, int n)
                 DLT_STRING("not running!"));
 }
 
-void logprocess_thread(void *v_conf)
+void logprocess_init(void *v_conf)
 {
     DLT_LOG(dltsystem, DLT_LOG_DEBUG,
             DLT_STRING("dlt-system-processes, in thread."));
@@ -133,29 +132,26 @@ void logprocess_thread(void *v_conf)
     DltSystemConfiguration *conf = (DltSystemConfiguration *)v_conf;
     DLT_REGISTER_CONTEXT(procContext, conf->LogProcesses.ContextId, "Log Processes");
 
-    int process_delays[DLT_SYSTEM_LOG_PROCESSES_MAX];
-    int i;
-
-    for (i = 0; i < conf->LogProcesses.Count; i++)
+    for (int i = 0; i < conf->LogProcesses.Count; i++)
         process_delays[i] = conf->LogProcesses.TimeDelay[i];
+}
 
-    while (!threads.shutdown) {
-        sleep(1);
-
-        for (i = 0; i < conf->LogProcesses.Count; i++) {
-            if (conf->LogProcesses.Mode[i] == SEND_MODE_OFF)
-                continue;
+void logprocess_fd_handler(void *v_conf)
+{
+    DltSystemConfiguration *conf = (DltSystemConfiguration *)v_conf;
+    for (int i = 0; i < conf->LogProcesses.Count; i++) {
+        if (conf->LogProcesses.Mode[i] == SEND_MODE_OFF)
+            continue;
 
-            if (process_delays[i] <= 0) {
-                send_process(&(conf->LogProcesses), i);
-                process_delays[i] = conf->LogProcesses.TimeDelay[i];
+        if (process_delays[i] <= 0) {
+            send_process(&(conf->LogProcesses), i);
+            process_delays[i] = conf->LogProcesses.TimeDelay[i];
 
-                if (conf->LogProcesses.Mode[i] == SEND_MODE_ONCE)
-                    conf->LogProcesses.Mode[i] = SEND_MODE_OFF;
-            }
-            else {
-                process_delays[i]--;
-            }
+            if (conf->LogProcesses.Mode[i] == SEND_MODE_ONCE)
+                conf->LogProcesses.Mode[i] = SEND_MODE_OFF;
+        }
+        else {
+            process_delays[i]--;
         }
     }
 }
diff --git a/src/system/dlt-system-syslog.c b/src/system/dlt-system-syslog.c
index 7808613..2995441 100644
--- a/src/system/dlt-system-syslog.c
+++ b/src/system/dlt-system-syslog.c
@@ -44,16 +44,16 @@
 *******************************************************************************/
 
 
-#include <pthread.h>
 #include <unistd.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <string.h>
 #include <errno.h>
 
-#include "dlt-system.h"
+#include <systemd/sd-journal.h>
+#include <poll.h>
 
-extern DltSystemThreads threads;
+#include "dlt-system.h"
 
 DLT_IMPORT_CONTEXT(dltsystem)
 DLT_DECLARE_CONTEXT(syslogContext)
@@ -134,29 +134,27 @@ int read_socket(int sock)
     recv_data[bytes_read] = '\0';
 
     if (bytes_read != 0)
+    {
         DLT_LOG(syslogContext, DLT_LOG_INFO, DLT_STRING(recv_data));
+    }
 
     return bytes_read;
 }
 
-void syslog_thread(void *v_conf)
+int register_syslog_fd(struct pollfd *pollfd, int i, DltSystemConfiguration *config)
 {
-    DLT_LOG(dltsystem, DLT_LOG_DEBUG,
-            DLT_STRING("dlt-system-syslog, in thread."));
-
-    DltSystemConfiguration *conf = (DltSystemConfiguration *)v_conf;
-    DLT_REGISTER_CONTEXT(syslogContext, conf->Syslog.ContextId, "SYSLOG Adapter");
-
-    int sock = init_socket(conf->Syslog);
-
-    if (sock < 0)
-        return;
-
-    while (!threads.shutdown)
-        if (read_socket(sock) < 0) {
-            close(sock);
-            return;
-        }
-
-    close (sock);
+    DLT_REGISTER_CONTEXT(syslogContext, config->Syslog.ContextId, "SYSLOG Adapter");
+    int syslogSock = init_socket(config->Syslog);
+    if (syslogSock < 0) {
+        DLT_LOG(dltsystem, DLT_LOG_ERROR, DLT_STRING("Could not init syslog socket\n"));
+        return -1;
+    }
+    pollfd[i].fd = syslogSock;
+    pollfd[i].events = POLLIN;
+    return syslogSock;
 }
+
+void syslog_fd_handler(int syslogSock)
+{
+    read_socket(syslogSock);
+}
\ No newline at end of file
diff --git a/src/system/dlt-system-watchdog.c b/src/system/dlt-system-watchdog.c
index fd6bcac..a2b01de 100644
--- a/src/system/dlt-system-watchdog.c
+++ b/src/system/dlt-system-watchdog.c
@@ -29,135 +29,95 @@
 #if defined(DLT_SYSTEMD_WATCHDOG_ENABLE)
 #include <stdio.h>
 #include <stdlib.h>
-#include <pthread.h>
+#include <string.h>
 #include <sys/timerfd.h>
 #include "dlt.h"
 #include "dlt-system.h"
-
-#include "sd-daemon.h"
-
+#include <poll.h>
+#include <systemd/sd-daemon.h>
 
 DLT_DECLARE_CONTEXT(watchdogContext)
 DLT_IMPORT_CONTEXT(dltsystem)
 
-extern DltSystemThreads threads;
-
-typedef struct
-{
-    int timer_fd;
-    unsigned long long wakeups_missed;
-} PeriodicData;
-
-void wait_period (PeriodicData *info)
-{
-    unsigned long long missed;
-
-    if (read (info->timer_fd, &missed, sizeof (missed)) < 0)
-        DLT_LOG(watchdogContext, DLT_LOG_ERROR,
-                DLT_STRING("Could not read from timer file descriptor in watchdog.\n"));
-
-    if (missed > 0)
-        info->wakeups_missed += (missed - 1);
-}
-
-int make_periodic(unsigned int period, PeriodicData *info)
+int calculate_period(struct itimerspec *itval)
 {
     unsigned int ns;
     unsigned int sec;
-    int fd;
-    struct itimerspec itval;
+    char str[512];
+    char *watchdogUSec;
+    unsigned int watchdogTimeoutSeconds;
+    unsigned int notifiyPeriodNSec;
+
+    watchdogUSec = getenv("WATCHDOG_USEC");
 
-    if (info == 0) {
-        DLT_LOG(watchdogContext, DLT_LOG_ERROR,
-                DLT_STRING("Invalid function parameters used for function make_periodic.\n"));
+    if (watchdogUSec == NULL) {
+        DLT_LOG(watchdogContext, DLT_LOG_ERROR, DLT_STRING("systemd watchdog timeout (WATCHDOG_USEC) is null\n"));
         return -1;
     }
+    
+    DLT_LOG(watchdogContext, DLT_LOG_DEBUG, DLT_STRING("watchdogusec: "), DLT_STRING(watchdogUSec));
+    watchdogTimeoutSeconds = atoi(watchdogUSec);
 
-    /* Create the timer */
-    fd = timerfd_create (CLOCK_MONOTONIC, 0);
-
-    info->wakeups_missed = 0;
-    info->timer_fd = fd;
-
-    if (fd == -1) {
-        DLT_LOG(watchdogContext, DLT_LOG_ERROR,
-                DLT_STRING("Can't create timer filedescriptor.\n"));
+    if (watchdogTimeoutSeconds <= 0) {
+        snprintf(str, 512, "systemd watchdog timeout incorrect: %u\n", watchdogTimeoutSeconds);
+        DLT_LOG(watchdogContext, DLT_LOG_ERROR, DLT_STRING(str));
         return -1;
     }
 
+    /* Calculate half of WATCHDOG_USEC in ns for timer tick */
+    notifiyPeriodNSec = watchdogTimeoutSeconds / 2;
+
+    snprintf(str,
+            512,
+            "systemd watchdog timeout: %u nsec - timer will be initialized: %u nsec\n",
+            watchdogTimeoutSeconds,
+            notifiyPeriodNSec);
+    DLT_LOG(watchdogContext, DLT_LOG_DEBUG, DLT_STRING(str));
+
     /* Make the timer periodic */
-    sec = period / 1000000;
-    ns = (period - (sec * 1000000)) * 1000;
-    itval.it_interval.tv_sec = sec;
-    itval.it_interval.tv_nsec = ns;
-    itval.it_value.tv_sec = sec;
-    itval.it_value.tv_nsec = ns;
-
-    return timerfd_settime (fd, 0, &itval, NULL);
+    sec = notifiyPeriodNSec / 1000000;
+    ns = (notifiyPeriodNSec - (sec * 1000000)) * 1000;
+    itval->it_interval.tv_sec = sec;
+    itval->it_interval.tv_nsec = ns;
+    itval->it_value.tv_sec = sec;
+    itval->it_value.tv_nsec = ns;
+
+    return 0;
 }
 
-
-void watchdog_thread(void *v_conf)
+int register_watchdog_fd(struct pollfd *pollfd, int fdcnt)
 {
-    char str[512];
-    char *watchdogUSec;
-    unsigned int watchdogTimeoutSeconds;
-    unsigned int notifiyPeriodNSec;
-    PeriodicData info;
-
     DLT_REGISTER_CONTEXT(watchdogContext, "DOG", "dlt system watchdog context.");
+    struct itimerspec timerValue;
+    if (calculate_period(&timerValue) != 0)
+        return -1;
 
-    sleep(1);
-
-    DLT_LOG(watchdogContext, DLT_LOG_INFO, DLT_STRING("Watchdog thread started.\n"));
-
-    if (v_conf == 0) {
-        DLT_LOG(watchdogContext, DLT_LOG_ERROR,
-                DLT_STRING("Invalid function parameters used for function watchdog_thread.\n"));
-        return;
+    int timerfd = timerfd_create(CLOCK_MONOTONIC, 0);
+    if (timerfd < 0) {
+        DLT_LOG(dltsystem, DLT_LOG_ERROR, DLT_STRING("Failed to create timer fd\n"));
+        return -1;
     }
+    pollfd[fdcnt].fd = timerfd;
+    pollfd[fdcnt].events = POLLIN;
 
-    watchdogUSec = getenv("WATCHDOG_USEC");
-
-    if (watchdogUSec) {
-        DLT_LOG(watchdogContext, DLT_LOG_DEBUG, DLT_STRING("watchdogusec: "), DLT_STRING(watchdogUSec));
-
-        watchdogTimeoutSeconds = atoi(watchdogUSec);
-
-        if (watchdogTimeoutSeconds > 0) {
-
-            /* Calculate half of WATCHDOG_USEC in ns for timer tick */
-            notifiyPeriodNSec = watchdogTimeoutSeconds / 2;
-
-            snprintf(str,
-                     512,
-                     "systemd watchdog timeout: %u nsec - timer will be initialized: %u nsec\n",
-                     watchdogTimeoutSeconds,
-                     notifiyPeriodNSec);
-            DLT_LOG(watchdogContext, DLT_LOG_DEBUG, DLT_STRING(str));
-
-            if (make_periodic (notifiyPeriodNSec, &info) < 0) {
-                DLT_LOG(watchdogContext, DLT_LOG_ERROR, DLT_STRING("Could not initialize systemd watchdog timer\n"));
-                return;
-            }
+    if (timerfd_settime(timerfd, 0, &timerValue, NULL) < 0) {
+        DLT_LOG(dltsystem, DLT_LOG_ERROR, DLT_STRING("Could not start timer\n"));
+        return -1;
+    }
+    return 0;
+}
 
-            while (1) {
-                if (sd_notify(0, "WATCHDOG=1") < 0)
-                    DLT_LOG(watchdogContext, DLT_LOG_ERROR, DLT_STRING("Could not reset systemd watchdog\n"));
+void watchdog_fd_handler(int fd)
+{
+    long int timersElapsed = 0;
+    int r = read(fd, &timersElapsed, 8);    // only needed to reset fd event
+    if(r < 0)
+        DLT_LOG(watchdogContext, DLT_LOG_ERROR, DLT_STRING("Could not reset systemd watchdog. Exit with: "), 
+            DLT_STRING(strerror(r)));
 
-                DLT_LOG(watchdogContext, DLT_LOG_DEBUG, DLT_STRING("systemd watchdog waited periodic\n"));
+    if (sd_notify(0, "WATCHDOG=1") < 0)
+        DLT_LOG(watchdogContext, DLT_LOG_ERROR, DLT_STRING("Could not reset systemd watchdog\n"));
 
-                /* Wait for next period */
-                wait_period(&info);
-            }
-        }
-        else {
-            snprintf(str, 512, "systemd watchdog timeout incorrect: %u\n", watchdogTimeoutSeconds);
-            DLT_LOG(watchdogContext, DLT_LOG_DEBUG, DLT_STRING(str));
-        }
-    }
-    else {
-        DLT_LOG(watchdogContext, DLT_LOG_ERROR, DLT_STRING("systemd watchdog timeout (WATCHDOG_USEC) is null\n"));
-    }
+    DLT_LOG(watchdogContext, DLT_LOG_DEBUG, DLT_STRING("systemd watchdog waited periodic\n"));
 }
-#endif
+#endif
\ No newline at end of file
diff --git a/src/system/dlt-system.c b/src/system/dlt-system.c
index 0b3cd0d..92ea466 100644
--- a/src/system/dlt-system.c
+++ b/src/system/dlt-system.c
@@ -112,11 +112,10 @@ int main(int argc, char *argv[])
     signal(SIGQUIT, dlt_system_signal_handler);
     signal(SIGINT, dlt_system_signal_handler);
 
-    DLT_LOG(dltsystem, DLT_LOG_DEBUG, DLT_STRING("Launching threads."));
+    DLT_LOG(dltsystem, DLT_LOG_DEBUG, DLT_STRING("Initializing all processes and starting poll for events."));
 
 
-    start_threads(&config);
-    join_threads();
+    start_dlt_system_processes(&config);
     return 0;
 }
 
diff --git a/src/system/dlt-system.conf b/src/system/dlt-system.conf
index 4010b70..58f56fa 100644
--- a/src/system/dlt-system.conf
+++ b/src/system/dlt-system.conf
@@ -90,10 +90,6 @@ FiletransferContextId = FILE
 # Time in seconds after startup of dlt-system when first file is transfered (Default: 0)
 FiletransferTimeStartup = 0
 
-# Time to wait when transfered file is deleted and next file transfer starts (Default: 10)
-# Time in seconds
-FiletransferTimeDelay = 10
-
 # Time in ms seconds to wait between two file transfer logs of a single file to DLT.  (Default: 10)
 FiletransferTimeoutBetweenLogs = 5
 
@@ -202,4 +198,3 @@ LogProcessTimeDelay = 5
 # LogProcessFilename = stat
 # LogProcessMode = 2
 # LogProcessTimeDelay = 1
-
diff --git a/src/system/dlt-system.h b/src/system/dlt-system.h
index e60cb9b..9be1cf4 100644
--- a/src/system/dlt-system.h
+++ b/src/system/dlt-system.h
@@ -54,6 +54,9 @@
 #ifndef DLT_SYSTEM_H_
 #define DLT_SYSTEM_H_
 
+#include <systemd/sd-journal.h>
+#include <poll.h>
+
 /* DLT related includes. */
 #include "dlt.h"
 #include "dlt_common.h"
@@ -70,13 +73,29 @@
 
 #define MAX_LINE 1024
 
-#define MAX_THREADS 8
+/** Total number of file descriptors needed for processing all features:
+*   - Journal file descriptor
+*   - Syslog file descriptor
+*   - Timer file descriptor for processing LogFile and LogProcesses every second
+*   - Inotify file descriptor for FileTransfer
+*   - Timer file descriptor for Watchdog 
+*/
+#define MAX_FD_NUMBER   5
 
 /* Macros */
 #define MALLOC_ASSERT(x) if (x == NULL) { \
         fprintf(stderr, "Out of memory\n"); \
         abort(); }
 
+/* enum for classification of FD */
+enum fdType {
+    fdType_journal = 0,
+    fdType_syslog,
+    fdType_filetransfer,
+    fdType_timer,
+    fdType_watchdog,
+};
+
 /**
  * Configuration structures.
  * Please see dlt-system.conf for explanation of all the options.
@@ -114,7 +133,6 @@ typedef struct {
     int Enable;
     char *ContextId;
     int TimeStartup;
-    int TimeDelay;
     int TimeoutBetweenLogs;
     char *TempDir;
 
@@ -126,6 +144,11 @@ typedef struct {
 } FiletransferOptions;
 
 typedef struct {
+    int handle;
+    int fd[DLT_SYSTEM_LOG_DIRS_MAX];
+} s_ft_inotify;
+
+typedef struct {
     int Enable;
 
     /* Variable number of files to transfer */
@@ -158,12 +181,6 @@ typedef struct {
     LogProcessOptions LogProcesses;
 } DltSystemConfiguration;
 
-typedef struct {
-    pthread_t threads[MAX_THREADS];
-    int count;
-    int shutdown;
-} DltSystemThreads;
-
 /**
  * Forward declarations for the whole application
  */
@@ -172,28 +189,28 @@ typedef struct {
 int read_command_line(DltSystemCliOptions *options, int argc, char *argv[]);
 int read_configuration_file(DltSystemConfiguration *config, char *file_name);
 
-/* In dlt-process-handling.c */
+/* For dlt-process-handling.c */
 int daemonize();
-void start_threads(DltSystemConfiguration *config);
-void start_thread(DltSystemConfiguration *conf,
-                  void (thread)(void *), const char *nam);
-void join_threads();
+void init_shell();
 void dlt_system_signal_handler(int sig);
-void register_with_dlt(DltSystemConfiguration *config);
 
-/* Threads */
-void init_shell();
-void syslog_thread(void *v_conf);
-void filetransfer_thread(void *v_conf);
-void logfile_thread(void *v_conf);
-void logprocess_thread(void *v_conf);
-
-#if defined(DLT_SYSTEMD_WATCHDOG_ENABLE)
-void watchdog_thread(void *v_conf);
-#endif
-
-#if defined(DLT_SYSTEMD_JOURNAL_ENABLE)
-void journal_thread(void *v_conf);
-#endif
+/* Main function for creating/registering all needed file descriptors and starting the poll for all of them. */
+void start_dlt_system_processes(DltSystemConfiguration *config);
+
+/* Init process, create file descriptors and register them into main pollfd. */
+int register_watchdog_fd(struct pollfd *pollfd, int fdcnt);
+int init_filetransfer_dirs(DltSystemConfiguration *config);
+void logfile_init(void *v_conf);
+void logprocess_init(void *v_conf);
+void register_journal_fd(sd_journal **j, struct pollfd *pollfd, int i,  DltSystemConfiguration *config);
+int register_syslog_fd(struct pollfd *pollfd, int i, DltSystemConfiguration *config);
+
+/* Routines that are called, when a fd event was raised. */
+void logfile_fd_handler(void *v_conf);
+void logprocess_fd_handler(void *v_conf);
+void filetransfer_fd_handler(DltSystemConfiguration *config);
+void watchdog_fd_handler(int fd);
+void journal_fd_handler(sd_journal *j, DltSystemConfiguration *config);
+void syslog_fd_handler(int syslogSock);
 
 #endif /* DLT_SYSTEM_H_ */