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/**
 * @file datatop_dev_poll.c
 * @brief Adds ability for data collection from /proc/net/dev
 *
 * File contains methods for searching and polling data from
 * "/proc/net/dev"
 */

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "datatop_interface.h"
#include "datatop_fileops.h"
#include "datatop_str.h"

#define DTOP_DEV_SIZE 8192
#define DTOP_DEV_LINE (DTOP_DEV_SIZE>>2)

/**
* @struct dtop_dev_vars
* @brief Struct used to hold necessary variables for /proc/net/dev dpg
*
* @var dtop_dev_vars::line
* Array of strings where necessary dp names and values are held.
* @var dtop_dev_vars::line_count
* Number of lines the file is that the dpg represents.
*/
struct dtop_dev_vars {
	char **line;
	int line_count;
};

/**
 * @brief Parses lines with data in "/proc/net/dev"
 *
 * @param line1 Line to parse to find datapoint names and values.
 * @param len1 Length of line1.
 * @param index Index in the dictionary the key (name) is added to.
 * @param dict Dictionary the keys and values are added to.
 */
static void dt_dev_parse(char *line1, int len1,
			 int index, struct dt_procdict *dict)
{
	int i, start = 0;
	int j, k, n;
	i = 0;
	while (line1[i] == '	' || line1[i] == ' ')
		i++;
	dict->key[index] = &line1[i];
	for (i = 0; i < len1; i++) {
		if (line1[i] == ':') {
			line1[i+1] = 0;
			start = i+2;
			break;
		}
	}

	k = 0;
	for (j = start; j < len1; j++) {
		if (line1[j] != '	' && line1[j] != ' ') {
			dict->val[k] = &line1[j];
			n = j;
			while (line1[n] != 0 && line1[n] != '	' && line1[n] != ' ')
				n++;
			if (n < len1)
				line1[n] = 0;
			j = n;
			k++;
		}
	}
}

/**
 * @brief Stores the data collected from "/proc/net/dev"
 *
 * @param dpg Struct that polled data is added to.
 * @return DTOP_POLL_IO_ERR - Poll of dpg unsuccessful.
 * @return DTOP_POLL_OK - Poll of dpg successful.
 */
int dtop_dev_poll(struct dtop_data_point_gatherer *dpg)
{
	char *data;
	int *line_len = malloc(sizeof(int) *
			((struct dtop_dev_vars *)
			(dpg->priv))->line_count);
	int read;
	struct dt_procdict *dict = malloc(sizeof(struct dt_procdict)
					*((struct dtop_dev_vars *)
					(dpg->priv))->line_count-2);
	int j, n, sum;
	int index = 0;
	int dp = 0;

	read = dt_read_file(dpg->file, &data, DTOP_DEV_SIZE);
	if (read == 0 || data == 0)
		return DTOP_POLL_IO_ERR;

	sum = 0;
	/* Assigns each line read from the file, a length */
	for (n = 0; n < ((struct dtop_dev_vars *)
				(dpg->priv))->line_count; n++) {
		line_len[n] = dt_read_line(((struct dtop_dev_vars *)
					(dpg->priv))->line[n],
					   DTOP_DEV_LINE, data,
					   DTOP_DEV_SIZE, sum);
		if (n <= (((struct dtop_dev_vars *)
			(dpg->priv))->line_count - 1)) {
			sum += (line_len[n] + 1);
		}

	}

	for (n = 2; n < ((struct dtop_dev_vars *)
			(dpg->priv))->line_count; n++) {
		dt_dev_parse(((struct dtop_dev_vars *)
				(dpg->priv))->line[n], line_len[n],
					index, &dict[index]);
		index++;
	}


	/* Assigns the dp value to the dp struct */
	for (n = 2; n < ((struct dtop_dev_vars *)
			(dpg->priv))->line_count; n++) {
		for (j = 0; j < 16; j++) {
			dtop_store_dp(&(dpg->data_points[dp]),
						dict[n-2].val[j]);
			dp++;
		}
	}

	dt_free(&data);
	free(line_len);
	free(dict);
	return DTOP_POLL_OK;
}

/**
 * @brief Frees dynamically allocated "/proc/net/dev" dpg.
 *
 * Frees the memory of the dpg along with it's data_points
 * and other malloc'd memory no longer needed.
 *
 * @param dpg Dpg to deconstruct and deallocate memory for.
 */
static void dtop_dev_dpg_deconstructor
			(struct dtop_data_point_gatherer *dpset)
{
	int i, j, dp;
	dp = 0;
	for (j = 0; j < ((((struct dtop_dev_vars *)
		(dpset->priv))->line_count)-2); j++) {
		for (i = 0; i < 16; i++) {
			free(dpset->data_points[dp].prefix);
			dp++;
		}
	}
	free(dpset->data_points);
	for (i = 0; i < ((struct dtop_dev_vars *)
				(dpset->priv))->line_count; i++)
		free(((struct dtop_dev_vars *)(dpset->priv))->line[i]);
	free(((struct dtop_dev_vars *)(dpset->priv))->line);
	free(((struct dtop_dev_vars *)(dpset->priv)));
	free(dpset);
}

/**
 * @brief Creates a dpg for "/proc/net/dev" file
 *
 * Dynamically allocates memory for dpg which is then added to a linked list
 * via the dtop_register(dpg) function call.
 *
 * @param data_points dtop_data_point struct that dpg points to.
 * @param storage dtop_dev_vars struct that holds relevant dpg variables.
 */
static void construct_dev_file_dpg(struct dtop_dev_vars *storage,
			int dp_count, struct dtop_data_point *data_points)
{
	struct dtop_data_point_gatherer *dpg = malloc
		(sizeof(struct dtop_data_point_gatherer));

	dpg->prefix = "/proc/net/dev";
	dpg->file = "/proc/net/dev";
	dpg->poll = dtop_dev_poll;
	dpg->data_points = data_points;
	dpg->priv = (struct dtop_dev_vars *)storage;
	dpg->data_points_len = dp_count;
	dpg->deconstruct = dtop_dev_dpg_deconstructor;

	dtop_register(dpg);
}

/**
 * @brief Scans "/proc/net/dev in order to autodetect dps.
 *
 * Searches through "/proc/net/dev" file for all available data
 * points to create as dp structs.
 *
 * @param name This is the file name "/proc/net/dev" passed in by dtop_dev_init
 * @param storage dtop_dev_vars struct where relevant variables are stored.
 */
int dtop_dev_search(char *name, struct dtop_dev_vars *storage)
{
	int i, n, sum;
	char *data;
	int *line_len = malloc(sizeof(int) * storage->line_count);
	int read;
	struct dt_procdict dict;
	struct dt_procdict dev_dict;
	struct dtop_data_point *data_points = malloc
		(sizeof(struct dtop_data_point) * 16 * (storage->line_count-2));
	int dp_count = (16 * (storage->line_count - 2));
	int index = 0;
	int dp = 0;

	storage->line = malloc(storage->line_count * sizeof(*storage->line));

	for (i = 0; i < storage->line_count; i++)
		storage->line[i] = malloc(sizeof(char) * DTOP_DEV_LINE);

	dev_dict.val[0] = "bytes";
	dev_dict.val[1] = "packets";
	dev_dict.val[2] = "errs";
	dev_dict.val[3] = "drop";
	dev_dict.val[4] = "fifo";
	dev_dict.val[5] = "frame";
	dev_dict.val[6] = "compressed";
	dev_dict.val[7] = "multicast";
	dev_dict.val[8] = "bytes";
	dev_dict.val[9] = "packets";
	dev_dict.val[10] = "errs";
	dev_dict.val[11] = "drop";
	dev_dict.val[12] = "fifo";
	dev_dict.val[13] = "colls";
	dev_dict.val[14] = "carrier";
	dev_dict.val[15] = "compressed";

	read = dt_read_file(name, &data, DTOP_DEV_SIZE);
	if (read == 0 || data == 0)
		return DTOP_POLL_IO_ERR;

	sum = 0;
	/* Assigns each line read from the file, a length */
	for (n = 0; n < storage->line_count; n++) {
		line_len[n] = dt_read_line(storage->line[n],
					   DTOP_DEV_LINE, data,
					   DTOP_DEV_SIZE, sum);
		if (n < (storage->line_count - 1))
			sum += (line_len[n] + 1);
	}

	construct_dev_file_dpg(storage, dp_count, data_points);

	for (n = 2; n < storage->line_count; n++) {
		dt_dev_parse(storage->line[n], line_len[n], index, &dict);
		index++;
	}

	for (n = 2; n < storage->line_count; n++) {
		for (i = 0; i < 16; i++) {
			char *pref = malloc(30 * sizeof(char));
			data_points[dp].skip = 0;
			data_points[dp].initial_data_populated = NOT_POPULATED;
			if (i < 8)
				strlcpy(pref, "Receive:", 30 * sizeof(char));
			else if (i >= 8)
				strlcpy(pref, "Transmit:", 30 * sizeof(char));
			strlcat(pref, dev_dict.val[i], 30 * sizeof(char));
			data_points[dp].prefix = pref;
			data_points[dp].name = dict.key[n-2];
			data_points[dp].type = DTOP_ULONG;
			dp++;
		}
		index++;
	}

	free(line_len);
	dt_free(&data);
	return DTOP_POLL_OK;
}

/**
 * @brief Calls dtop_search for "/proc/net/dev" file.
 */
void dtop_dev_init(void)
{
	struct dtop_dev_vars *storage = malloc
			(sizeof(struct dtop_dev_vars));
	storage->line_count = dtop_get_file_line_amount("/proc/net/dev");
	dtop_dev_search("/proc/net/dev", storage);
}