int fstatus = stat(destinationPath, &buffer);

  if(fstatus == -1)

    {

      // Download the Tar

      int ret = curlget(url, destinationPath);

      if(ret == 0){

        fprintf(stderr, "Job data retrieved successfully\n");

        // free(url); @FIXME: causes doublefree! Curl must free the url?

        return 0;

      }

      else if(ret == 1){

        fprintf(stderr, "Downloading job data from %s failed. Check your network connection.\n",url);

        free(url);

        return 1; // Eventually make a retry loop

      }

    }

  fprintf(stderr, "Tar already exists! Download cancelled.\n");

  return 2;

}

int uploadOutput(char *pathtoOutput, char *urltoOutput, int jobnum, int framenum, int slavekey){

  //fprintf(stderr,"Uploading output %s to url %s for job %d and frame %d for slavekey %d", pathtoOutput, urltoOutput, jobnum, framenum, slavekey);

  if( !curlpost(pathtoOutput, urltoOutput, jobnum, framenum, slavekey)) // Uploads output

    {

      if(DEBUG)

        fprintf(stderr,"Upload successful, removing old output...\n");

      else

        fprintf(stderr,"Upload completed\n");

      remove(pathtoOutput); // Delete the file after its uploaded

      return 0;

    }

  else

    {

      fprintf(stderr,"Upload failed. Check your network connection. Retrying upload...\n");

      int tries=1;

      while(tries<=10 && curlpost(pathtoOutput, urltoOutput, jobnum, framenum, slavekey))

        {

          fprintf(stderr, "Upload failed. Trying again in 10 seconds... (attempt %d of 10)\n", tries);

          tries++;

          sleep(10);

        }

      return 1; // Upload failed after multiple tries

      // @FUTURE: Keep track of files that we were unable to upload, and upload them later

    }

}

/**

   Extracts archive to the specified directory, creating this directory

   if necessary (but this directory will not be recursively created).

   @param outdir output directory

   @param pathtoTar filename of the archive to extract

 */

int unpackJob(char *outdir, char *pathtoTar)

{

  int ret;

  struct archive *a;

  struct archive_entry *ae;

  int astatus;

  /* ignore return because directory may exist already */

  mkdir(outdir, 0700);

  ret = chdir(outdir);

  if(ret == -1)

    {

      perror("chdir");

      return 1;

    }

  a = archive_read_new();

  ae = archive_entry_new();

  archive_read_support_compression_all(a);

  archive_read_support_format_raw(a);

  astatus = archive_read_open_filename(a, pathtoTar, 8192);

  if (astatus != ARCHIVE_OK)

    {

      fprintf(stderr, "error opening archive\n");

      return 1;

    }

  for(astatus = ARCHIVE_OK;

      astatus == ARCHIVE_OK

	|| astatus == ARCHIVE_WARN;

      )

    {

      astatus = archive_read_next_header2(a, ae);

      if(astatus == ARCHIVE_WARN)

	fprintf(stderr, "Encountered nonfatal read error somehow\n");

      if(astatus == ARCHIVE_OK

	 || astatus == ARCHIVE_WARN)

	astatus = archive_read_extract(a, ae,

				       ARCHIVE_EXTRACT_NO_OVERWRITE

				       | ARCHIVE_EXTRACT_SECURE_SYMLINKS

				       | ARCHIVE_EXTRACT_SECURE_NODOTDOT);

    }

  archive_entry_free(ae);

  archive_read_finish(a);

  if(astatus != ARCHIVE_EOF)

    {

      fprintf(stderr, "Error reading archive\n");

      return 1;

    }

  return 0;

}

void prepareJobPaths(int jobnum, int framenum, char *outputExt, char *datadir, char **urltoTar,char **pathtoTar,char **pathtoTardir,char **pathtoJob, char **pathtoJobfile, char **urltoJobfile, char **urltoOutput,char **pathtoOutput, char **pathtoRenderOutput, char **pathtoOutdir)

{

  // Variable Preparation

  char *jobdatapath;

   _distren_asprintf(&jobdatapath, "job%d", jobnum);

   _distren_asprintf(urltoTar, "http://data.distren.org/job%d/job%d.tar.gz", jobnum, jobnum); // Prepares URL to download from

   _distren_asprintf(urltoJobfile, "http://data.distren.org/job%d/job.blend", jobnum); // Prepares URL to download from

   _distren_asprintf(pathtoTar, "%s/%s/job%d.tar.gz", datadir, jobdatapath, jobnum); // Prepares destination to save to

   _distren_asprintf(pathtoTardir, "%s/%s/", datadir, jobdatapath); // Prepares destination to save to

   _distren_asprintf(pathtoJob, "%s/%s/", datadir, jobdatapath);

   _distren_asprintf(pathtoJobfile, "%s/%s/job.blend", datadir, jobdatapath ); // Prepares the path to the jobfile

   _distren_asprintf(urltoOutput, "http://dev.distren.org/slaveUpload.php?jobkey=%d&framekey=%d",jobnum,framenum); // Prepares the URL where output is posted

   _distren_asprintf(pathtoRenderOutput, "%s/%s/output/job%d-frame#.%s", datadir, jobdatapath, jobnum, outputExt ); // Note: the # is for blender to put in framenum in output file

   _distren_asprintf(pathtoOutput, "%s/%s/output/job%d-frame%d.%s", datadir, jobdatapath, jobnum, framenum, outputExt ); // Note: the # is for blender to put in framenum in output file

   _distren_asprintf(pathtoOutdir, "%s/%s/output", datadir, jobdatapath);

   free(jobdatapath);

}

int checkUsername(char *username)

{

  if(username == NULL || strcmp(username, "!username") == 0 )

    {

     fprintf(stderr, "\nPlease ensure that your username is present in distrenslave.conf\n");

     return 1;

   }

   else

     if( username != NULL || strcmp(username, "!username") != 0 )

       {

         // Log in the user

         if(login_user(username) == 1){

           // Logged in OK

           return 0;

         }

         else

           {

             fprintf(stderr, "Login failed, please check your username. If you have not registered, please do so on the DistRen website.\n");

             return 1;

           }

       }

     else

       {

         fprintf(stderr, "Please check your distrenslave.conf, it appears to be incorrectly formatted.\n");

         return 1;

       }

}

void slaveTest(char *datadir)

{

  int command;

  int test = 1;

  int jobnum = 0;

  int framenum = 0;

  int slavekey = 0;

  fprintf(stderr,"Hello!\n");

  char tmpString1[100] = "";

  char tmpString2[100] = "";

  char *uploadURL = "http://distren.org/slaveUpload.php";

  while(test == 1)

   {

     fprintf(stderr, "Welcome to DistRenSlave Alpha Interactive Test Mode\n\n");

     fprintf(stderr, "\t1 \tTest posting (uploading) data\n");

     fprintf(stderr, "\t2 \tTest getting frame from server\n");

     fprintf(stderr, "\t3 \tTest data downloading\n");

     fprintf(stderr, "\t4 \tTest archive decompression\n");

     fprintf(stderr, "\t5 \tQuit\n");

     scanf("%d", &command);

     switch(command)

     {

     case 1:

       fprintf(stderr,"Path to output file to upload: ");

       scanf("%99s", tmpString1);

       fprintf(stderr,"Framenum that is being uploaded: ");

       scanf("%d", &framenum);

       fprintf(stderr,"Jobnum that frame belongs to: ");

       scanf("%d", &jobnum);

       fprintf(stderr,"Slavekey that rendered this output: ");

       scanf("%d", &slavekey);

       uploadOutput(tmpString1, uploadURL, jobnum, framenum, slavekey);

       break;

     case 2:

       fprintf(stderr,"Remotio not implemented yet!\n");

       break;

     case 3:

       fprintf(stderr,"URL to file: ");

       scanf("%s", tmpString1);

       fprintf(stderr,"Local save path (including filename): ");

       scanf("%s", tmpString2);

       if(downloadTar(tmpString1, tmpString2))

         fprintf(stderr,"Error downloading!\n");

       else

         fprintf(stderr,"Success!\n");

       break;

     case 4:

       fprintf(stderr,"Jobnum to decompress: ");

       scanf("%d", &jobnum);

       fprintf(stderr,"Path to compressed data: ");

       scanf("%s", tmpString2);

       unpackJob(datadir, tmpString1);

       break;

     case 5:

       test = 0;

       break;

     default:

       fprintf(stderr, "Invalid input, please try again.\n");

       break;

     }

   }

}

/*

int runBenchmark(int slavekey, char *datadir){

  // Execute blender

  if(exec_blender(pathtoJobfile, pathtoOutput, framenum))

    {

      fprintf(stderr,"Error running Blender. Check your installation and/or your PATH.\n");

      _web_resetframe(slavekey, password, jobnum, framenum);  // Unassign the frame on the server so other slaves can render it

      return 1;

    }

  free(pathtoJobfile);

  struct stat buffer;

  int fstatus = stat(pathtoOutput, &buffer);

  if(fstatus == -1){

    fprintf(stderr,"*** Frame was not rendered correctly! Scene may not have camera, or your blender installation is not working.\n");

    _web_resetframe(slavekey, password, jobnum, framenum);  // Unassign the frame on the server so other slaves can render it

    return 1;

  }

}

*/

/* simpleSlave functions */

/** Memory struct for curl */

struct _web_memorystruct {

  char *memory;

  size_t size;

};

void *_web_myrealloc(void *ptr, size_t size);

void *_web_myrealloc(void *ptr, size_t size)

{

  /* There might be a realloc() out there that doesn't like reallocing

     NULL pointers, so we take care of it here */

  if(ptr)

    return realloc(ptr, size);

  else

    return malloc(size);

}

size_t _web_writememorycallback(void *ptr, size_t size, size_t nmemb, void *data)

{

  size_t realsize = size * nmemb;

  struct _web_memorystruct *mem = (struct _web_memorystruct *)data;

  mem->memory = _web_myrealloc(mem->memory, mem->size + realsize + 1);

  if (mem->memory) {

    memcpy(&(mem->memory[mem->size]), ptr, realsize);

    mem->size += realsize;

    mem->memory[mem->size] = 0;

  }

  return realsize;

}

struct _web_memorystruct _web_getrequest(char *url){

  // fprintf(stderr,"Preparing to get request at %s",url);

  CURL *curl;

  CURLcode res;

  struct _web_memorystruct chunk;

  chunk.memory=NULL; /* we expect realloc(NULL, size) to work */

  chunk.size = 0;    /* no data at this point */

  curl = curl_easy_init();

  if(curl) {

    curl_easy_setopt(curl, CURLOPT_URL, url);

    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, _web_writememorycallback);

    curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&chunk);

    curl_easy_setopt(curl, CURLOPT_USERAGENT, "libcurl-agent/1.0");

    res = curl_easy_perform(curl);

    curl_easy_cleanup(curl);

  }

  /* we're done with libcurl, so clean it up */

  curl_global_cleanup();

  return chunk; // 0 is OK, 1 is 404 or other error

}

void _web_finishframe(int slavekey, char *slavepass, int jobnum, int framenum){

  char *url;

  _distren_asprintf(&url,"http://dev.distren.org/slave/act.php?mode=finishframe&slavekey=%d&slavepass=%s&jobnum=%d&framenum=%d", slavekey, slavepass, jobnum, framenum);

  struct _web_memorystruct data = _web_getrequest(url);

  free(url);

  fprintf(stderr,"%s\n", data.memory);

  if(data.memory)

    free(data.memory);

}

void _web_resetframe(int slavekey, char *slavepass, int jobnum, int framenum){

  fprintf(stderr,"Resetting frame %d in job %d on server... ",framenum,jobnum);

  char *url;

  _distren_asprintf(&url,"http://dev.distren.org/slave/act.php?mode=resetframe&slavekey=%d&slavepass=%s&jobnum=%d&framenum=%d", slavekey, slavepass, jobnum, framenum);

  struct _web_memorystruct data = _web_getrequest(url);

  free(url);

  fprintf(stderr,"%s\n", data.memory);

  if(data.memory)

    free(data.memory);

}

void _web_startframe(int slavekey, char *slavepass, int jobnum, int framenum){

  if(DEBUG)

    fprintf(stderr,"Marking frame %d started on server... ",framenum);

  char *url;

  _distren_asprintf(&url,"http://dev.distren.org/slave/act.php?mode=startframe&slavekey=%d&slavepass=%s&jobnum=%d&framenum=%d", slavekey, slavepass, jobnum, framenum);

  struct _web_memorystruct data = _web_getrequest(url);

  free(url);

  fprintf(stderr,"%s\n", data.memory);

  if(data.memory)

    free(data.memory);

}

int _web_getwork(int slavekey, char *slavepass, int *jobnum, int *framenum){

  char *url;

  _distren_asprintf(&url,"http://dev.distren.org/slave/act.php?mode=getwork&slavekey=%d&slavepass=%s", slavekey, slavepass);

  struct _web_memorystruct data = _web_getrequest(url);

  free(url);

  if(!data.memory || !strcmp(data.memory,",")){

    fprintf(stderr,"No work available on server!\n");

    return 0;

  }

  else if(!strcmp(data.memory, "ERROR_BADKEY")){

    fprintf(stderr,"*** Slave %d does not exist!\n",slavekey);

    free(data.memory);

    return 0;

  }

  // Compare to PACKAGE_VERSION

  else{

    char *tmp;

    char *serverversion;

    tmp = strtok (data.memory,",,");

    if(tmp != NULL){ // make sure work is available

      *jobnum = atoi(tmp);

      tmp = strtok (NULL, ",");

      if(tmp == NULL)

        return 0; // no work

      *framenum = atoi(tmp);

      tmp = strtok (NULL, ",");

      if(tmp == NULL)

        return 0; // no work

      serverversion = tmp;

      if(strcmp(PACKAGE_VERSION,serverversion)){

        fprintf(stderr,"Your distren package is out of date! Please acquire a newer version. (%s local vs %s remote)\n", PACKAGE_VERSION, serverversion);

        return 0;

      }

      free(data.memory);

      return 1;

    }

    else

      return 0; // error

  }

}

void _web_setrenderpower(int slavekey, char *slavepass, int renderpower){

  fprintf(stderr,"Setting render power on server... ");

  char *url;

  _distren_asprintf(&url,"http://dev.distren.org/slave/act.php?mode=setrenderpower&slavekey=%d&slavepass=%s&renderpower=%d", slavekey, slavepass, renderpower);

  struct _web_memorystruct data = _web_getrequest(url);

  free(url);

  fprintf(stderr,"%s\n", data.memory);

  if(data.memory)

    free(data.memory);

}

int slaveBenchmark(char *datadir, int *benchmarkTime, int *renderPower){

  int ret;

  int frameToRender = 1;

  char *frame_str;

  _distren_asprintf(&frame_str, "%d", frameToRender); // Render frame 1

  char *output;

  _distren_asprintf(&output, "%s/benchmark#.jpg", datadir); // Where to save benchmark output

  char *realOutput;

  _distren_asprintf(&realOutput, "%s/benchmark%d.jpg", datadir, frameToRender); // Where to save benchmark output

  char *input;

  _distren_asprintf(&input, "%s/benchmark.blend", datadir); // Input file

  fprintf(stderr,"Downloading benchmark data...\n");

  curlget("http://data.distren.org/benchmark.blend", input); // Download to input file location

  char *command = "blender"; // @TODO: We currently expect this to be in PATH

  char *cmd[] = { command, "-b", input, "-o", output, "-f", frame_str, "-t", "0", (char *)NULL }; // arguments for blender

  // fprintf(stderr,"Preparing to execute command: %s -b %s -o %s -f %s\n", command, input, output, frame_str);

  fprintf(stderr,"Running benchmark...\n");

  long startTime;

  long endTime;

  time(&startTime);

  char buf[20];

  struct execio *testrem;

  size_t readlen;

  ret = execio_open(&testrem, command, cmd);

  if(ret)

    {

      fprintf(stderr, "Error executing blender\n");

      return 1;

    }

  buf[19] = '\0';

  while(!execio_read(testrem, buf, 19, &readlen))

    {

       buf[readlen] = '\0';

       fprintf(stderr, "read \"%s\"\n", buf);

    }

  execio_close(testrem);

  time(&endTime);

  struct stat buffer;

  int ostatus = stat(realOutput, &buffer);

  if(ostatus == -1){

    ret = 1; // Return error if output wasn't generated

  }

  else

    remove(output);

  *benchmarkTime = abs(difftime(startTime,endTime));

  float tmp = *benchmarkTime;

  tmp = (1/tmp) * 50000;

  *renderPower = (int)tmp;

  free(realOutput);

  free(frame_str);

  free(input);

  free(output);

  return ret;

}