Still working on the daemonization (and rewrite).

I am not sure that what I am doing is going to provide what was
requested in https://github.com/nsensfel/relabsd/issues/3 but it will at
the very least turn relabsd into a proper daemon, and the additions will
help create some kind of relabsd device manager if someone needs such a
thing.

5 files changed, 356 insertions, 12 deletions

diff --git a/src/server/communication_node.c b/src/server/communication_node.c
new file mode 100644
index 0000000..70c7323
--- /dev/null
+++ b/src/server/communication_node.c
@@ -0,0 +1,177 @@
+/**** POSIX *******************************************************************/
+#include <sys/socket.h>
+#include <sys/un.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <string.h>
+#include <unistd.h>
+
+/**** RELABSD *****************************************************************/
+#include <relabsd/debug.h>
+
+/******************************************************************************/
+/**** LOCAL FUNCTIONS *********************************************************/
+/******************************************************************************/
+
+static int create_socket (int result [const restrict static 1])
+{
+   errno = 0;
+
+   *result = socket(AF_UNIX, SOCK_STREAM, 0);
+
+   if (*result == -1)
+   {
+      RELABSD_FATAL
+      (
+         "Unable to create server socket: %s.",
+         strerror(errno)
+      );
+
+      return -1;
+   }
+
+   return 0;
+}
+
+static int bind_socket
+(
+   const char socket_name [const restrict static 1],
+   const int socket
+)
+{
+   struct sockaddr_un addr;
+
+
+   memset(&addr, 0, sizeof(struct sockaddr_un));
+
+   addr.sun_family = AF_UNIX;
+
+   strncpy
+   (
+      (void *) addr.sun_path,
+      (const void *) socket_name,
+      (sizeof(addr.sun_path) - 1)
+   );
+
+   errno = 0;
+
+   if
+   (
+      bind
+      (
+         socket,
+         (const struct sockaddr *) &addr,
+         (socklen_t) sizeof(struct sockaddr_un)
+      )
+      == -1
+   )
+   {
+      RELABSD_FATAL
+      (
+         "Unable to bind communication socket to %s: %s.",
+         socket_name,
+         strerror(errno)
+      );
+
+      return -1;
+   }
+
+   return 0;
+}
+
+static int set_socket_to_unblocking (const int socket)
+{
+   int current_flags;
+
+   errno = 0;
+   current_flags = fcntl(socket, F_GETFD);
+
+   if (current_flags == -1)
+   {
+      RELABSD_FATAL
+      (
+         "Unable to get communication socket properties: %s.",
+         strerror(errno)
+      );
+
+      return -1;
+   }
+
+   errno = 0;
+   current_flags = fcntl(socket, F_SETFD, (current_flags | O_NONBLOCK));
+
+   if (current_flags == -1)
+   {
+      RELABSD_FATAL
+      (
+         "Unable to set communication socket properties: %s.",
+         strerror(errno)
+      );
+
+      return -2;
+   }
+
+   return 0;
+}
+
+static int set_socket_as_listener (const int socket)
+{
+   errno = 0;
+
+   if (listen(socket, 0) == -1)
+   {
+      RELABSD_FATAL
+      (
+         "Unable to set server socket properties: %s.",
+         strerror(errno)
+      );
+
+      return -1;
+   }
+
+   return 0;
+}
+
+/******************************************************************************/
+/**** EXPORTED FUNCTIONS ******************************************************/
+/******************************************************************************/
+int relabsd_server_create_communication_node
+(
+   const char socket_name [const restrict static 1],
+   int socket [const restrict static 1]
+)
+{
+   if (create_socket(socket) < 0)
+   {
+      return -1;
+   }
+
+   if (bind_socket(socket_name, *socket) < 0)
+   {
+      /* TODO: err message. */
+      (void) close(*socket);
+
+      return -1;
+   }
+
+   /*
+   if (set_socket_to_unblocking(*socket) < 0)
+   {
+      /* TODO: err message. *//*
+      (void) close(*socket);
+
+      return -1;
+   }
+   */
+
+   if (set_socket_as_listener(*socket) < 0)
+   {
+      /* TODO: err message. */
+      (void) close(*socket);
+
+      return -1;
+   }
+
+   return 0;
+}
diff --git a/src/server/communication_thread.c b/src/server/communication_thread.c
new file mode 100644
index 0000000..2ed1aae
--- /dev/null
+++ b/src/server/communication_thread.c
@@ -0,0 +1,55 @@
+/**** POSIX *******************************************************************/
+#include <pthread.h>
+#include <string.h>
+
+/**** RELABSD *****************************************************************/
+#include <relabsd/debug.h>
+
+/******************************************************************************/
+/**** LOCAL FUNCTIONS *********************************************************/
+/******************************************************************************/
+void main_loop (struct relabsd_server server [const static 1])
+{
+
+}
+
+void * posix_main_loop (void * params)
+{
+   main_loop((struct relabsd_server *) params);
+
+   return NULL;
+}
+
+/******************************************************************************/
+/**** EXPORTED FUNCTIONS ******************************************************/
+/******************************************************************************/
+
+int relabsd_server_create_communication_thread
+(
+   struct relabsd_server server [const static 1]
+)
+{
+   int err;
+
+   err =
+      pthread_create
+      (
+         &(server->communication_thread),
+         (const pthread_attr_t *) NULL,
+         posix_main_loop,
+         (void *) server
+      );
+
+   if (err != 0)
+   {
+      RELABSD_FATAL
+      (
+         "Unable to create the communication thread: %s",
+         strerror(err)
+      );
+
+      return -1;
+   }
+
+   return 0;
+}
diff --git a/src/server/main_loop.c b/src/server/conversion_main_loop.c
index 7db1423..0180e80 100644
--- a/src/server/main_loop.c
+++ b/src/server/conversion_main_loop.c
@@ -163,3 +163,11 @@ int main (int argc, char ** argv)
    return 0;
 }
 */
+
+int relabsd_server_conversion_loop
+(
+   struct relabsd_server server [const static 1]
+)
+{
+   return 0;
+}
diff --git a/src/server/daemon.c b/src/server/daemon.c
index 7b8e736..c8561f3 100644
--- a/src/server/daemon.c
+++ b/src/server/daemon.c
@@ -1,14 +1,13 @@
 /**** POSIX *******************************************************************/
-#include <sys/types.h>
+#include <sys/stat.h>
 
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
 #include <unistd.h>
 
 /**** RELABSD *****************************************************************/
-#include <relabsd/config.h>
 #include <relabsd/debug.h>
-#include <relabsd/server.h>
-
-#include <relabsd/config/parameters.h>
 
 /******************************************************************************/
 /**** LOCAL FUNCTIONS *********************************************************/
@@ -26,10 +25,24 @@
  */
 int relabsd_server_create_daemon (void)
 {
+   int unnamed_pipe[2];
    pid_t proc_id;
 
+   errno = 0;
+
+   if (pipe(unnamed_pipe) == -1)
+   {
+      RELABSD_FATAL
+      (
+         "Unable to create an unnamed pipe for the daemon creation process: %s",
+         strerror(errno)
+      );
+
+      return -1;
+   }
+
    /* 1/ Close all open file descriptors ... **********************************/
-   /* None were opened at this point. */
+   /* None were opened at this point, except the pipe, which is still needed. */
 
    /* 2/ Reset all signal handlers ... ****************************************/
    /* Those were not modified at this point. */
@@ -57,10 +70,52 @@ int relabsd_server_create_daemon (void)
 
    if (proc_id != ((pid_t) 0))
    {
+      char buffer;
+
+      /* Close the writing end of the pipe, as this process does not use it */
+      errno = 0;
+
+      if (close(unnamed_pipe[1]) == -1)
+      {
+         RELABSD_ERROR
+         (
+            "Unable to close writing end of an unnamed pipe during the daemon"
+            " creation process: %s.",
+            strerror(errno)
+         );
+      }
+
       /* Awaiting step 14...*/
-      /* TODO: insert unnamed pipe */
+      errno = 0;
+
+      if (read(unnamed_pipe[0], &buffer, (size_t) 1) == -1)
+      {
+         RELABSD_ERROR
+         (
+            "Unable to read from reading end of an unnamed pipe during the "
+            " daemon creation process: %s.",
+            strerror(errno)
+         );
+      }
+
+      if (close(unnamed_pipe[0]) == -1)
+      {
+         RELABSD_ERROR
+         (
+            "Unable to close reading end of an unnamed pipe during the daemon"
+            " creation process: %s.",
+            strerror(errno)
+         );
+      }
+
       /* 15/ Original process exits *******************************************/
-      exit();
+      exit(0);
+   }
+
+   /* Close reading on the pipe, as this process does not use it */
+   if (close(unnamed_pipe[0]))
+   {
+
    }
 
    /* 6/ setsid() *************************************************************/
@@ -96,13 +151,26 @@ int relabsd_server_create_daemon (void)
 
    if (proc_id != ((pid_t) 0))
    {
+      if (close(unnamed_pipe[1]) == -1)
+      {
+         RELABSD_ERROR
+         (
+            "Unable to close writing end of an unnamed pipe during the daemon"
+            " creation process: %s.",
+            strerror(errno)
+         );
+      }
+
       /* 8/ First child process exits *****************************************/
-      exit();
+      exit(0);
    }
 
    /* 9/ /dev/null for standard input/outputs *********************************/
+   /* TODO. */
 
    /* 10/ reset umask to 0 ****************************************************/
+   /* Can't fail, returns previous mask. */
+   (void) umask(0);
 
    /* 11/ Set current directory to / ******************************************/
    errno = 0;
@@ -110,6 +178,13 @@ int relabsd_server_create_daemon (void)
    if (chdir("/") == -1)
    {
       // Can't print an error message at that point though...
+      RELABSD_FATAL
+      (
+         "Step 11 of the daemon creation process, fork(), failed: %s.",
+         strerror(errno)
+      );
+
+      /* TODO: boop main process. */
       return -1;
    }
 
@@ -117,10 +192,30 @@ int relabsd_server_create_daemon (void)
    /* Don't want to limit to a single instance. */
 
    /* 13/ Drop privileges *****************************************************/
+   /* We need those. */
 
    /* 14/ Signal completion ***************************************************/
+   if (write(unnamed_pipe[0], (void *) "!", (size_t) 1) == -1)
+   {
+      RELABSD_ERROR
+      (
+         "Unable to write to writing end of an unnamed pipe during the daemon"
+         " creation process: %s.",
+         strerror(errno)
+      );
+   }
 
    /* Step 15 is done on the very first process. */
 
+   if (close(unnamed_pipe[1]) == -1)
+   {
+      RELABSD_ERROR
+      (
+         "Unable to close writing end of an unnamed pipe during the daemon"
+         " creation process: %s.",
+         strerror(errno)
+      );
+   }
+
    return 0;
 }
diff --git a/src/server/server.c b/src/server/server.c
index debeb91..ddd9bdf 100644
--- a/src/server/server.c
+++ b/src/server/server.c
@@ -33,7 +33,7 @@ int initialize
    (
       relabsd_virtual_device_create
       (
-
+         relabsd_parameters_get_virtual_device_name(params),
          &(server->virtual_device)
       )
       < 0
@@ -56,14 +56,23 @@ int initialize
       return -3;
    }
 
+   if (relabsd_parameters_get_communication_node(params) != ((char *) NULL))
+   {
+      relabsd_server_create_communication_thread(&server);
+   }
+
    return 0;
 }
 
 void finalize (struct relabsd_server server [const static 1])
 {
-   if (relabsd_parameters_get_communication_node(params) != ((...) NULL))
+   if
+   (
+      relabsd_parameters_get_communication_node(server->parameters)
+      != ((char *) NULL)
+   )
    {
-      relabsd_server_join_communication_node(&server);
+      relabsd_server_join_communication_thread(&server);
    }
 
    relabsd_virtual_device_destroy(&(server->virtual_device));