datatop/src/datatop_gen_poll.c

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/**
 * @file datatop_gen_poll.c
 * @brief Contains functions which add ability to scan directories for data points.
 *
 * Contains functions that search through a directory and create dpg's for any
 * important data values found which can then be polled for data collection.
 */

#include <unistd.h>
#include <stdio.h>
#include <dirent.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/stat.h>
#include <sys/types.h>

#include "datatop_interface.h"
#include "datatop_fileops.h"
#include "datatop_str.h"
#include "datatop_gen_poll.h"

#define DTOP_GEN_SIZE 8192
#define DTOP_GEN_LINE (DTOP_GEN_SIZE>>2)

/**
 * @brief Searches a file to find the number of data values it contains.
 *
 * @param dpg The struct which contains the file to search.
 * @return Number of datapoints found in the file.
 */
static int get_number_of_values(struct dtop_data_point_gatherer *dpg)
{
	char *data;
	int read;
	char line[DTOP_GEN_LINE];
	int line_len;
	int i, num;

	read = dt_read_file(dpg->file, &data, DTOP_GEN_SIZE);
	line_len = dt_read_line(line, DTOP_GEN_LINE, data, DTOP_GEN_SIZE, 0);

	if (read == 0) {
		return 0;
	}

	if (line_len < 1) {
		dt_free(&data);
		return 0;
	}

	num = 1;
	for (i = 0; i < line_len; i++) {
		if ((line[i] == ' ' || line[i] == ','
		    || line[i] == '	') &&line[i+1] != 0)
			num++;
	}

	dt_free(&data);
	return num;
}

/**
 * @brief Stores the data collected from a dpg that was constructed during dtop_search.
 *
 * @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_gen_poll(struct dtop_data_point_gatherer *dpg)
{
	char *data;
	int read;
	char line[DTOP_GEN_LINE];
	int line_len;
	struct dt_procdict dict;
	int i;

	read = dt_read_file(dpg->file, &data, DTOP_GEN_SIZE);
	line_len = dt_read_line(line, DTOP_GEN_LINE, data, DTOP_GEN_SIZE, 0);

	if (read == 0 || data == 0)
		return DTOP_POLL_IO_ERR;

	dt_single_line_parse(line, line_len, &dict);

	for (i = 0; i < dpg->data_points_len; i++) {
		if (dict.val[i][0] == '-')
			dpg->data_points[i].type = DTOP_LONG;
		dtop_store_dp(&(dpg->data_points[i]), dict.val[i]);
	}

	dt_free(&data);
	return DTOP_POLL_OK;
}

/**
 * @brief Frees dynamically allocated dpg's.
 *
 * Frees the memory of dpg variables and the dpg for all dynamically allocated
 * dpgs.
 *
 * @param dpg Dpg to deconstruct and deallocate memory for.
 */
static void dtop_gen_dpg_deconstructor(struct dtop_data_point_gatherer *dpset)
{
	int i;
	for (i = 0; i < dpset->data_points_len; i++)
		free(dpset->data_points[i].name);
	free(dpset->data_points);
	free(dpset->file);
	free(dpset->prefix);
	free(dpset);
}

/**
 * @brief Creates a dpg and all necessary dp's corresponding to it.
 *
 * Dynamically allocates memory for dpg and dp structs which are then
 * created and added to a linked_list of dpgs through the dtop_register
 * function.
 *
 * @param dir Directory which file is located in, assigned to the dpg prefix.
 * @param name Name of file that dpg represents, assigned to a dp name.
 */
static void dpg_construction(char *dir, char *name)
{
	int num, i;
	int both_len = strlen(dir) + strlen(name) + 1;
	char *both = malloc(both_len);
	char *maindir;
	struct dtop_data_point_gatherer *dpg = malloc
	       (sizeof(struct dtop_data_point_gatherer));
	strlcpy(both, dir, both_len);
	strlcat(both, name, both_len);
	maindir = malloc(strlen(dir) + 1);
	strlcpy(maindir, dir, strlen(dir) + 1);

	dpg->prefix = maindir;
	dpg->file = both;
	dpg->poll = dtop_gen_poll;
	dpg->deconstruct = dtop_gen_dpg_deconstructor;
	num = get_number_of_values(dpg);

	if (num != 0) {
		struct dtop_data_point *dp = malloc
		       (num * sizeof(struct dtop_data_point));
		for (i = 0; i < num; i++) {
			if (num == 1) {
				dp[i].name = malloc(strlen(name) + 1);
				strlcpy(dp[i].name, name, strlen(name) + 1);
			} else {
				char *add = malloc(7 * sizeof(char));
				char *newname;
				int nn_len, dpn_len;
				snprintf(add, 7 * sizeof(char), "[%d]:", i);
				nn_len = strlen(name) + strlen(add) + 1;
				newname = malloc(nn_len);
				strlcpy(newname, name, nn_len);
				strlcat(newname, add, nn_len);
				dpn_len = strlen(newname) + 1;
				dp[i].name = malloc(dpn_len);
				strlcpy(dp[i].name, newname, dpn_len);
				free(add);
				free(newname);
			}
			dp[i].prefix = NULL;
			dp[i].type = DTOP_ULONG;
			dp[i].skip = DO_NOT_SKIP;
			dp[i].initial_data_populated = NOT_POPULATED;
		}

		dpg->data_points = dp;
		dpg->data_points_len = num;

		dtop_register(dpg);
	} else {
		free(dpg->prefix);
		free(dpg->file);
		free(dpg);
	}
}

/**
 * @brief Scans a directory for all important datapoints to be collected.
 *
 * Recursively scans a directory and locates all files which data will be
 * collected from.
 *
 * @param dir Directory to search.
 */
static int dtop_search(char *dir)
{
	DIR *dp;
	struct dirent *entry;
	struct stat s;
	char cwd[1024];

	if (!getcwd(cwd, sizeof(cwd))) {
		fprintf(stderr, "Failed to get current working dir\n");
		return -1;
	}

	dp = opendir(dir);
	if (dp == NULL) {
		fprintf(stderr, "err=%d: %s\n", errno, strerror(errno));
		fprintf(stderr, "Cannot open directory: %s\n", dir);
		return DIR_FAILURE;
	}

	chdir(dir);

	while ((entry = readdir(dp))) {
		if (stat(entry->d_name, &s)) {
			printf("stat err=%d: %s\n", errno, strerror(errno));
			return DIR_FAILURE;
		}

		if (strcmp(".", entry->d_name) != 0 &&
		   strcmp("..", entry->d_name) != 0 &&
		   S_ISREG(s.st_mode)) {

			dpg_construction(dir, entry->d_name);

		} else if (strcmp(".", entry->d_name) != 0 &&
			strcmp("..", entry->d_name) != 0 &&
			S_ISDIR(s.st_mode)) {
			int nd_len = strlen(dir) + strlen(entry->d_name) + 2;
			char *newdir = malloc(nd_len);
			strlcpy(newdir, dir, nd_len);
			strlcat(newdir, entry->d_name, nd_len);
			strlcat(newdir, "/", nd_len);
			dtop_search(newdir);
			free(newdir);
		}
	}

	closedir(dp);
	chdir(cwd);
	return DIR_SUCCESS;
}

/**
 * @brief Calls dtop_search for any specified directory.
 *
 * @param dir Directory to search.
 */
void dtop_gen_init(char *dir)
{
	dtop_search(dir);
}