user_dl.c

This a framework to test new ideas in transmission technology. Actual development is a LDPC-coder in

/***************************************************************************
             user.c  -  Implements all the necessary functions for user-space
                            -------------------
    begin                :  2002
    authors              :  Linus Gasser
    emails               :  [e-mail]
 ***************************************************************************/

/***************************************************************************
                                 Changes
                                 -------
 date - name - description
 02-10-09 - ineiti- begin
 02-12-09 - ineiti - added userprocfs
 
 **************************************************************************/

/***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/


/**
 * This is the library a user-space-test program has to link against.
 * It offers all kinds of different functions that are available in
 * RTLinux kernel-space and that need to be emulated in user-space.
 * Have fun...
 */


#include <stdlib.h>
#include <dlfcn.h>
#include "debugging.h"

#define DBG_LVL 0


typedef struct modlist_t {
  char name[256];
  void *handle;
  struct modlist_t *next, *prev;
}
modlist;

modlist *first;


modlist *addList( char *name ) {
  modlist *n;

  n = malloc( sizeof( modlist ) );
  strncpy( n->name, name, 256 );
  n->next = first;
  n->prev = first->prev;
  n->prev->next = n;
  first->prev = n;

  return n;
}


void *rmList( char *name ) {
  modlist *n;
  void *handle = NULL;

  for ( n = first->next; n != first; n = n->next ) {
    if ( strcmp( n->name, name ) == 0 ) {
      handle = n->handle;
      n->prev->next = n->next;
      n->next->prev = n->prev;
      free( n );
    }
  }
  return handle;
}


/**
 * Gets the module 'name' and returns 0 on success. This also
 * initialises the module.
 */
int loadModule( char *name ) {
  void *handle;
  char path[256];
  int (*daq_start)(int);

  // Our name convention, so as to distinct from other things
  if ( sprintf( path, "libswr_%s.so", name ) >= 256 ) {
    PR_DBG( 0, "OOPS, the name %s is toooo long\n", name );
    return -1;
  }

  // All symbols should be checked for NOW and should be available
  // also later
  handle = dlopen( path, RTLD_NOW | RTLD_GLOBAL );

  if ( !handle ) {
    PR_DBG( 0, "Error on loading: %s\n", dlerror() );
    return -1;
  }

  if ( strcmp( name, "emul" ) == 0 ) {
    daq_start = dlsym( handle, "swr_daq_dma_start" );
  }

  addList( name )->handle = handle;
  return 0;
}


/**
 * Frees a loaded module, calling the 'exit'-function
 */
int freeModule( char *n ) {
  void *handle;
  char name[256];

  strncpy( name, n, 256 );
  handle = rmList( name );
  if ( handle ) {
    PR_DBG( 4, "removing %s\n", name );
    dlclose( handle );
    return 0;
  } else {
    PR_DBG( 0, "couldn't find %s for freeing\n", name );
    return -1;
  }
}

/**
 * Delete all resting modules
 */
void freeAll() {
  // Getting rid of all modules
  while ( first->next != first->prev ) {
    PR_DBG( 4, "Freeing %s\n", first->prev->name );
    freeModule( first->prev->name );
    //    sleep( 1 );
  }
}


int user_dl_init( void ) {
  PR_DBG( 4, "Initialising user\n" );
  // Initialise the modules-list
  first = malloc( sizeof( modlist ) );
  first->prev = first->next = first;
  return 0;
}


void user_dl_fini( void ) {
  PR_DBG( 4, "Stopping user, cleaning up modules\n" );

  freeAll();
  free( first );
}