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plugin_netdev.c

/* $Id: plugin_netdev.c,v 1.14 2005/05/08 04:32:44 reinelt Exp $
 *
 * plugin for /proc/net/dev parsing
 *
 * Copyright (C) 2003 Michael Reinelt <reinelt@eunet.at>
 * Copyright (C) 2004 The LCD4Linux Team <lcd4linux-devel@users.sourceforge.net>
 *
 * This file is part of LCD4Linux.
 *
 * LCD4Linux 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, or (at your option)
 * any later version.
 *
 * LCD4Linux 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 this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 *
 * $Log: plugin_netdev.c,v $
 * Revision 1.14  2005/05/08 04:32:44  reinelt
 * CodingStyle added and applied
 *
 * Revision 1.13  2005/01/18 06:30:23  reinelt
 * added (C) to all copyright statements
 *
 * Revision 1.12  2004/06/26 12:05:00  reinelt
 *
 * uh-oh... the last CVS log message messed up things a lot...
 *
 * Revision 1.11  2004/06/26 09:27:21  reinelt
 *
 * added '-W' to CFLAGS
 * changed all C++ comments to C ones
 * cleaned up a lot of signed/unsigned mistakes
 *
 * Revision 1.10  2004/06/17 10:58:58  reinelt
 *
 * changed plugin_netdev to use the new fast hash model
 *
 * Revision 1.9  2004/06/17 06:23:43  reinelt
 *
 * hash handling rewritten to solve performance issues
 *
 * Revision 1.8  2004/05/27 03:39:47  reinelt
 *
 * changed function naming scheme to plugin::function
 *
 * Revision 1.7  2004/03/11 06:39:59  reinelt
 * big patch from Martin:
 * - reuse filehandles
 * - memory leaks fixed
 * - earlier busy-flag checking with HD44780
 * - reuse memory for strings in RESULT and hash
 * - netdev_fast to wavid time-consuming regex
 *
 * Revision 1.6  2004/03/03 04:44:16  reinelt
 * changes (cosmetics?) to the big patch from Martin
 * hash patch un-applied
 *
 * Revision 1.5  2004/03/03 03:47:04  reinelt
 * big patch from Martin Hejl:
 * - use qprintf() where appropriate
 * - save CPU cycles on gettimeofday()
 * - add quit() functions to free allocated memory
 * - fixed lots of memory leaks
 *
 * Revision 1.4  2004/02/15 07:23:04  reinelt
 * bug in netdev parsing fixed
 *
 * Revision 1.3  2004/02/01 19:37:40  reinelt
 * got rid of every strtok() incarnation.
 *
 * Revision 1.2  2004/01/29 04:40:02  reinelt
 * every .c file includes "config.h" now
 *
 * Revision 1.1  2004/01/25 05:30:09  reinelt
 * plugin_netdev for parsing /proc/net/dev added
 *
 */

/* 
 * exported functions:
 *
 * int plugin_init_netdev (void)
 *  adds functions to access /proc/net/dev
 *
 */


#include "config.h"

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>

#include "debug.h"
#include "plugin.h"
#include "qprintf.h"
#include "hash.h"


static HASH NetDev;
static FILE *Stream = NULL;
static char *DELIMITER = " :|\t\n";

static int parse_netdev(void)
{
    int age;
    int row, col;
    static int first_time = 1;

    /* reread every 10 msec only */
    age = hash_age(&NetDev, NULL);
    if (age > 0 && age <= 10)
      return 0;

    if (Stream == NULL)
      Stream = fopen("/proc/net/dev", "r");
    if (Stream == NULL) {
      error("fopen(/proc/net/dev) failed: %s", strerror(errno));
      return -1;
    }

    rewind(Stream);
    row = 0;

    while (!feof(Stream)) {
      char buffer[256];
      char dev[16];
      char *beg, *end;
      unsigned int len;

      if (fgets(buffer, sizeof(buffer), Stream) == NULL)
          break;

      switch (++row) {

      case 1:
          /* skip row 1 */
          continue;

      case 2:
          /* row 2 used for headers */
          if (first_time) {
            char *RxTx = strrchr(buffer, '|');
            first_time = 0;
            col = 0;
            beg = buffer;
            while (beg) {
                char key[32];

                while (strchr(DELIMITER, *beg))
                  beg++;
                if ((end = strpbrk(beg, DELIMITER)) != NULL)
                  *end = '\0';
                qprintf(key, sizeof(key), "%s_%s", beg < RxTx ? "Rx" : "Tx", beg);
                hash_set_column(&NetDev, col++, key);
                beg = end ? end + 1 : NULL;
            }
          }
          continue;

      default:
          /* fetch interface name (1st column) as key */
          beg = buffer;
          while (*beg && *beg == ' ')
            beg++;
          end = beg + 1;
          while (*end && *end != ':')
            end++;
          len = end - beg;
          if (len >= sizeof(dev))
            len = sizeof(dev) - 1;
          strncpy(dev, beg, len);
          dev[len] = '\0';

          hash_put_delta(&NetDev, dev, buffer);
      }
    }

    return 0;
}

static void my_netdev(RESULT * result, RESULT * arg1, RESULT * arg2, RESULT * arg3)
{
    char *dev, *key;
    int delay;
    double value;

    if (parse_netdev() < 0) {
      SetResult(&result, R_STRING, "");
      return;
    }

    dev = R2S(arg1);
    key = R2S(arg2);
    delay = R2N(arg3);

    value = hash_get_regex(&NetDev, dev, key, delay);

    SetResult(&result, R_NUMBER, &value);
}

static void my_netdev_fast(RESULT * result, RESULT * arg1, RESULT * arg2, RESULT * arg3)
{
    char *dev, *key;
    int delay;
    double value;

    if (parse_netdev() < 0) {
      SetResult(&result, R_STRING, "");
      return;
    }

    dev = R2S(arg1);
    key = R2S(arg2);
    delay = R2N(arg3);

    value = hash_get_delta(&NetDev, dev, key, delay);

    SetResult(&result, R_NUMBER, &value);
}


int plugin_init_netdev(void)
{
    hash_create(&NetDev);
    hash_set_delimiter(&NetDev, " :|\t\n");

    AddFunction("netdev", 3, my_netdev);
    AddFunction("netdev::fast", 3, my_netdev_fast);
    return 0;
}

void plugin_exit_netdev(void)
{
    if (Stream != NULL) {
      fclose(Stream);
      Stream = NULL;
    }
    hash_destroy(&NetDev);
}

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