datatop/src/datatop.c - LeafOS-Project/android_vendor_qcom_opensource_dataservices - Gitiles

 /************************************************************************
 Copyright (c) 2015-2016, The Linux Foundation. All rights reserved.

 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are
 met:
     * Redistributions of source code must retain the above copyright
       notice, this list of conditions and the following disclaimer.
     * Redistributions in binary form must reproduce the above
       copyright notice, this list of conditions and the following
       disclaimer in the documentation and/or other materials provided
       with the distribution.
     * Neither the name of The Linux Foundation nor the names of its
       contributors may be used to endorse or promote products derived
       from this software without specific prior written permission.

 THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
 WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
 ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
 BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
 OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
 IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 ************************************************************************/

 /**
 * @file datatop.c
 * @brief Executes commands for application.
 *
 * Contains the main() function where program executes. Calls appropriate
 * methods based on user's CLI commands. Executes parsing function to
 * determine necessary output and handles errors which may arise during the
 * parse. Initiliazes files for data collection. Will call functions designed
 * to poll and print the data in understandable format.
 */

 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/time.h>
 #include <sys/resource.h>
 #include <unistd.h>
 #include <string.h>
 #include <errno.h>
 #include <time.h>
 #include <pthread.h>
 #include "datatop_interface.h"
 #include "datatop_linked_list.h"
 #include "datatop_opt.h"
 #include "datatop_fileops.h"
 #include "datatop_polling.h"
 #include "datatop_gen_poll.h"


 #define DTOP_SEC_TO_USEC(x) ((x)*1000000)
 #define DTOP_USEC_TO_SEC(x) ((x)/1000000)
 struct dtop_linked_list *first_dpg_list;
 struct cli_opts usr_cl_opts;

 /**
  * @brief Prints the datapoint names and values to the terminal.
  *
  * @param dpg_list A pointer to the first node of a linked list which
  *                 contains all data_point_gatherer structs to print.
  */
 void dtop_print_terminal(struct dtop_linked_list *dpg_list)
 {
 	struct dtop_linked_list *curr_ptr = dpg_list;
 	struct dtop_data_point_gatherer *dpset;

 	while (curr_ptr) {
 		dpset = (struct dtop_data_point_gatherer *) curr_ptr->data;
 		dtop_print_dpg(dpset);
 		curr_ptr = curr_ptr->next_ptr;
 	}
 }

 /**
  * @brief Polls the data periodically and prints to file specified by the user.
  *
  * Polls the data as often as specified by the user in their CLI arguments
  * and outputs the data to a file also specified in CLI arguments. Then prints
  * a snapshot of delta(dp_value) to the terminal.
  *
  * @param dpg_list A pointer to the first node of a linked list which contains
  *                 all data_point_gatherer structs to poll and print.
  * @param fw A pointer to the file which will be printed to.
  * @return FILE_ERROR - Writing to file was unsuccessful.
  * @return FILE_SUCCESS - Writing to file was successful.
  */
 int dtop_poll_periodically(struct dtop_linked_list *dpg_list, FILE *fw)
 {
 	struct timeval tv, timeout;
 	fd_set rfds;
 	time_t curtime, endtime;
 	int inp, quit = 0;
 	struct dtop_linked_list *curr_ptr = dpg_list;
 	struct dtop_data_point_gatherer *dpset;
 	struct timeval ftime, itime, polltime;

 	gettimeofday(&tv, NULL);
 	curtime = DTOP_SEC_TO_USEC(tv.tv_sec)+tv.tv_usec;
 	endtime = DTOP_SEC_TO_USEC(tv.tv_sec)+ DTOP_SEC_TO_USEC(usr_cl_opts.poll_time);

 	/* print all of our datapoint names as column headers in csv format */
 	if (fprintf(fw, "\"Time\",") < 0)
 		return FILE_ERROR;

 	while (curr_ptr) {
 		dpset = (struct dtop_data_point_gatherer *) curr_ptr->data;
 		if (dtop_print_dpg_names_csv(dpset, fw) == FILE_ERROR)
 			return FILE_ERROR;
 		curr_ptr = curr_ptr->next_ptr;
 	}
 	if (fprintf(fw, "\n") < 0)
 		return FILE_ERROR;

 	dtop_print_interactive_opts();
 	gettimeofday(&itime, NULL);
 	/* periodically poll the datapoints and print in csv format */
 	while (curtime < endtime
 		|| usr_cl_opts.poll_time == POLL_NOT_SPECIFIED) {
 		FD_ZERO(&rfds);
 		FD_SET(0, &rfds);
 		timeout.tv_sec = DTOP_USEC_TO_SEC(usr_cl_opts.poll_per);
 		timeout.tv_usec = (usr_cl_opts.poll_per%1000000);
 		//ftime is right before timeout calculations for most acurate calculations
 		gettimeofday(&ftime, NULL);
 		timersub(&ftime, &itime, &polltime);
 		timersub(&timeout,&polltime, &timeout);
 		inp = select(1, &rfds, NULL, NULL, &timeout);
 		gettimeofday(&itime, NULL);
 		if (inp) {
 			char s[4];
 			scanf("%s", s);
 			if (strcmp(s, "quit") == 0
 			    || strcmp(s, "q") == 0) {
 				quit = QUIT;
 				break;
 			}
 			if (strcmp(s, "i") == 0) {
 				dtop_print_snapshot_diff(first_dpg_list);
 				dtop_reset_dp_initial_values(first_dpg_list);
 			}
 			if (strcmp(s, "l") == 0)
 				dtop_print_snapshot_diff(first_dpg_list);
 		}
 		gettimeofday(&tv, NULL);
 		curtime = DTOP_SEC_TO_USEC(tv.tv_sec)+tv.tv_usec;
 		dtop_poll(dpg_list);
 		if (dtop_print_time_at_poll(fw) == FILE_ERROR)
 			return FILE_ERROR;
 		if (dtop_write_pollingdata_csv(dpg_list, fw) == FILE_ERROR)
 		        return FILE_ERROR;

 	}

 	if (quit != QUIT)
 		dtop_print_snapshot_diff(dpg_list);
 	return FILE_SUCCESS;
 }

 static void dtop_set_niceness(int niceness)
 {
 	int pid, rc;
 	pid = getpid();
 	printf("Requesting nice %d\n", niceness);
 	rc = setpriority(PRIO_PROCESS, pid, niceness);
 	if (rc != 0)
 		fprintf(stderr, "Error setting priority [%d]\n", errno);

 	rc = getpriority(PRIO_PROCESS, pid);
 	printf("Running with nice %d.\n", rc);
 }

 int main(int argc, char **argv)
 {
 	int parse_status;
 	pthread_t tid;
 	printf("DataTop - Version %s\n", VERSION);
 	printf("(c)2014-2015 Linux Foundation\n");

 	dtop_load_default_options(&usr_cl_opts);

 	parse_status = dtop_parse_cli_opts(&usr_cl_opts, argc, argv);
 	switch (parse_status) {
 	case PARSE_SUCCESS:
 		dtop_set_niceness(usr_cl_opts.priority);
 	break;

 	case PARSE_FORCE_EXIT:
 		exit(EXIT_SUCCESS);
 	break;

 	case PARSE_FAILURE:
 	default:
 		printf("Failed to parse command line arguments.\n");
 		exit(EXIT_FAILURE);
 	break;
 	}

 	if (usr_cl_opts.iptables_rules_routes == OPT_CHOSE) {
 		if (usr_cl_opts.out_dir[0] == '\0') {
 			printf("Please provide an out directory.\n");
 			exit(EXIT_FAILURE);
 		}
 	}

 	dtop_dual_line_init("/proc/net/netstat");
 	dtop_dual_line_init("/proc/net/snmp");
 	dtop_single_line_init("/proc/net/snmp6");
 	dtop_gen_init("/proc/sys/net/");
 	dtop_gen_init("/sys/module/rmnet/parameters/");
 	dtop_gen_init("/sys/module/rmnet_perf/parameters/");
 	dtop_gen_init("/sys/module/rmnet_shs/parameters/");
 	dtop_gen_init("/sys/module/rmnet_data/parameters/");
 	dtop_gen_init("/sys/class/net/rmnet_mhi0/statistics/");
 	dtop_gen_init("/sys/class/net/usb_rmnet0/statistics/");
 	dtop_gen_init("/sys/class/net/rmnet_ipa0/statistics/");
 	dtop_meminfo_init();
 	dtop_dev_init();
 	dtop_stat_init();
 	dtop_cpu_stats_init();
 	dtop_gen_init("/sys/kernel/debug/clk/bimc_clk/");
 	dtop_gen_init("/sys/kernel/debug/clk/snoc_clk/");
 	dtop_gen_init("/sys/kernel/debug/clk/pnoc_clk/");

 	if (usr_cl_opts.iptables_rules_routes == OPT_CHOSE) {
 		printf("Datatop IP Tables, rules, routes\n");
 		dtop_ip_table_init(usr_cl_opts.out_dir);
 		if(0 != pthread_create(&tid, NULL, &dtop_ip_table_start_poll, NULL)) {
 			printf("Unable to create capture_ip_tables_rules_routes thread\n");
 		}
 	}

 	if (usr_cl_opts.print_cl == OPT_CHOSE) {
 		dtop_poll(first_dpg_list);
 		dtop_print_terminal(first_dpg_list);
 	}

 	if (usr_cl_opts.print_csv == OPT_CHOSE) {
 		FILE *to_file = NULL;
 		if ((dtop_open_writing_file(usr_cl_opts.file_name,
 						&to_file)) == VALID) {
 			printf("\nData being polled for %ld seconds.\n",
 						usr_cl_opts.poll_time);
 			if (dtop_poll_periodically(first_dpg_list, to_file)
 			    == FILE_ERROR) {
 				fprintf(stderr, "err=%d: %s\n", errno,
 							strerror(errno));
 				dtop_close_file(to_file);
 				deconstruct_dpgs(first_dpg_list);
 				dtop_rem_linked_list(first_dpg_list);
 				exit(EXIT_FAILURE);
 			}
 			dtop_close_file(to_file);
 		} else {
 			printf("File Can Not Be Opened\n");
 			exit(EXIT_FAILURE);
 		}
 	}

 	if (usr_cl_opts.snapshot_file) {
 		if (dtop_print_system_snapshot(usr_cl_opts.snapshot_file)
 			    == FILE_ERROR) {
 			fprintf(stderr, "err=%d: %s\n", errno,
 						strerror(errno));
 			deconstruct_dpgs(first_dpg_list);
 			dtop_rem_linked_list(first_dpg_list);
 			exit(EXIT_FAILURE);
 		}
 	}

 	if (usr_cl_opts.print_cl == OPT_NOT_CHOSE &&
 	    usr_cl_opts.print_csv == OPT_NOT_CHOSE) {
 		if ((!usr_cl_opts.snapshot_file)
 		   || usr_cl_opts.poll_time_selected == POLL_TIME_SELECTED) {
 			printf("\nData will now be polled for %ld seconds.\n",
 							usr_cl_opts.poll_time);
 			dtop_poll(first_dpg_list);
 			sleep(usr_cl_opts.poll_time);
 			dtop_poll(first_dpg_list);
 			dtop_print_snapshot_diff(first_dpg_list);
 		}
 	}

 	deconstruct_dpgs(first_dpg_list);
 	dtop_rem_linked_list(first_dpg_list);
 	return 0;
 }

 /**
  * @brief Adds each dpg as a node to a linked list.
  *
  * Called when a dpg is initialized.
  *
  * @param dpg A pointer to a data_point_gatherer struct which is to be added to the linked list.
  */
 void dtop_register(struct dtop_data_point_gatherer *dpg)
 {
 	if (dpg)
 		first_dpg_list = dtop_add_linked_list(dpg, first_dpg_list);
 }
	/************************************************************************
	Copyright (c) 2015-2016, The Linux Foundation. All rights reserved.

	Redistribution and use in source and binary forms, with or without
	modification, are permitted provided that the following conditions are
	met:
	* Redistributions of source code must retain the above copyright
	notice, this list of conditions and the following disclaimer.
	* Redistributions in binary form must reproduce the above
	copyright notice, this list of conditions and the following
	disclaimer in the documentation and/or other materials provided
	with the distribution.
	* Neither the name of The Linux Foundation nor the names of its
	contributors may be used to endorse or promote products derived
	from this software without specific prior written permission.

	THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
	WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
	MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
	ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
	BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
	CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
	SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
	BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
	WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
	OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
	IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	************************************************************************/

	/**
	* @file datatop.c
	* @brief Executes commands for application.
	*
	* Contains the main() function where program executes. Calls appropriate
	* methods based on user's CLI commands. Executes parsing function to
	* determine necessary output and handles errors which may arise during the
	* parse. Initiliazes files for data collection. Will call functions designed
	* to poll and print the data in understandable format.
	*/

	#include <stdio.h>
	#include <stdlib.h>
	#include <sys/time.h>
	#include <sys/resource.h>
	#include <unistd.h>
	#include <string.h>
	#include <errno.h>
	#include <time.h>
	#include <pthread.h>
	#include "datatop_interface.h"
	#include "datatop_linked_list.h"
	#include "datatop_opt.h"
	#include "datatop_fileops.h"
	#include "datatop_polling.h"
	#include "datatop_gen_poll.h"


	#define DTOP_SEC_TO_USEC(x) ((x)*1000000)
	#define DTOP_USEC_TO_SEC(x) ((x)/1000000)
	struct dtop_linked_list *first_dpg_list;
	struct cli_opts usr_cl_opts;

	/**
	* @brief Prints the datapoint names and values to the terminal.
	*
	* @param dpg_list A pointer to the first node of a linked list which
	* contains all data_point_gatherer structs to print.
	*/
	void dtop_print_terminal(struct dtop_linked_list *dpg_list)
	{
	struct dtop_linked_list *curr_ptr = dpg_list;
	struct dtop_data_point_gatherer *dpset;

	while (curr_ptr) {
	dpset = (struct dtop_data_point_gatherer *) curr_ptr->data;
	dtop_print_dpg(dpset);
	curr_ptr = curr_ptr->next_ptr;
	}
	}

	/**
	* @brief Polls the data periodically and prints to file specified by the user.
	*
	* Polls the data as often as specified by the user in their CLI arguments
	* and outputs the data to a file also specified in CLI arguments. Then prints
	* a snapshot of delta(dp_value) to the terminal.
	*
	* @param dpg_list A pointer to the first node of a linked list which contains
	* all data_point_gatherer structs to poll and print.
	* @param fw A pointer to the file which will be printed to.
	* @return FILE_ERROR - Writing to file was unsuccessful.
	* @return FILE_SUCCESS - Writing to file was successful.
	*/
	int dtop_poll_periodically(struct dtop_linked_list dpg_list, FILE fw)
	{
	struct timeval tv, timeout;
	fd_set rfds;
	time_t curtime, endtime;
	int inp, quit = 0;
	struct dtop_linked_list *curr_ptr = dpg_list;
	struct dtop_data_point_gatherer *dpset;
	struct timeval ftime, itime, polltime;

	gettimeofday(&tv, NULL);
	curtime = DTOP_SEC_TO_USEC(tv.tv_sec)+tv.tv_usec;
	endtime = DTOP_SEC_TO_USEC(tv.tv_sec)+ DTOP_SEC_TO_USEC(usr_cl_opts.poll_time);

	/* print all of our datapoint names as column headers in csv format */
	if (fprintf(fw, "\"Time\",") < 0)
	return FILE_ERROR;

	while (curr_ptr) {
	dpset = (struct dtop_data_point_gatherer *) curr_ptr->data;
	if (dtop_print_dpg_names_csv(dpset, fw) == FILE_ERROR)
	return FILE_ERROR;
	curr_ptr = curr_ptr->next_ptr;
	}
	if (fprintf(fw, "\n") < 0)
	return FILE_ERROR;

	dtop_print_interactive_opts();
	gettimeofday(&itime, NULL);
	/* periodically poll the datapoints and print in csv format */
	while (curtime < endtime
	\|\| usr_cl_opts.poll_time == POLL_NOT_SPECIFIED) {
	FD_ZERO(&rfds);
	FD_SET(0, &rfds);
	timeout.tv_sec = DTOP_USEC_TO_SEC(usr_cl_opts.poll_per);
	timeout.tv_usec = (usr_cl_opts.poll_per%1000000);
	//ftime is right before timeout calculations for most acurate calculations
	gettimeofday(&ftime, NULL);
	timersub(&ftime, &itime, &polltime);
	timersub(&timeout,&polltime, &timeout);
	inp = select(1, &rfds, NULL, NULL, &timeout);
	gettimeofday(&itime, NULL);
	if (inp) {
	char s[4];
	scanf("%s", s);
	if (strcmp(s, "quit") == 0
	\|\| strcmp(s, "q") == 0) {
	quit = QUIT;
	break;
	}
	if (strcmp(s, "i") == 0) {
	dtop_print_snapshot_diff(first_dpg_list);
	dtop_reset_dp_initial_values(first_dpg_list);
	}
	if (strcmp(s, "l") == 0)
	dtop_print_snapshot_diff(first_dpg_list);
	}
	gettimeofday(&tv, NULL);
	curtime = DTOP_SEC_TO_USEC(tv.tv_sec)+tv.tv_usec;
	dtop_poll(dpg_list);
	if (dtop_print_time_at_poll(fw) == FILE_ERROR)
	return FILE_ERROR;
	if (dtop_write_pollingdata_csv(dpg_list, fw) == FILE_ERROR)
	return FILE_ERROR;

	}

	if (quit != QUIT)
	dtop_print_snapshot_diff(dpg_list);
	return FILE_SUCCESS;
	}

	static void dtop_set_niceness(int niceness)
	{
	int pid, rc;
	pid = getpid();
	printf("Requesting nice %d\n", niceness);
	rc = setpriority(PRIO_PROCESS, pid, niceness);
	if (rc != 0)
	fprintf(stderr, "Error setting priority [%d]\n", errno);

	rc = getpriority(PRIO_PROCESS, pid);
	printf("Running with nice %d.\n", rc);
	}

	int main(int argc, char **argv)
	{
	int parse_status;
	pthread_t tid;
	printf("DataTop - Version %s\n", VERSION);
	printf("(c)2014-2015 Linux Foundation\n");

	dtop_load_default_options(&usr_cl_opts);

	parse_status = dtop_parse_cli_opts(&usr_cl_opts, argc, argv);
	switch (parse_status) {
	case PARSE_SUCCESS:
	dtop_set_niceness(usr_cl_opts.priority);
	break;

	case PARSE_FORCE_EXIT:
	exit(EXIT_SUCCESS);
	break;

	case PARSE_FAILURE:
	default:
	printf("Failed to parse command line arguments.\n");
	exit(EXIT_FAILURE);
	break;
	}

	if (usr_cl_opts.iptables_rules_routes == OPT_CHOSE) {
	if (usr_cl_opts.out_dir[0] == '\0') {
	printf("Please provide an out directory.\n");
	exit(EXIT_FAILURE);
	}
	}

	dtop_dual_line_init("/proc/net/netstat");
	dtop_dual_line_init("/proc/net/snmp");
	dtop_single_line_init("/proc/net/snmp6");
	dtop_gen_init("/proc/sys/net/");
	dtop_gen_init("/sys/module/rmnet/parameters/");
	dtop_gen_init("/sys/module/rmnet_perf/parameters/");
	dtop_gen_init("/sys/module/rmnet_shs/parameters/");
	dtop_gen_init("/sys/module/rmnet_data/parameters/");
	dtop_gen_init("/sys/class/net/rmnet_mhi0/statistics/");
	dtop_gen_init("/sys/class/net/usb_rmnet0/statistics/");
	dtop_gen_init("/sys/class/net/rmnet_ipa0/statistics/");
	dtop_meminfo_init();
	dtop_dev_init();
	dtop_stat_init();
	dtop_cpu_stats_init();
	dtop_gen_init("/sys/kernel/debug/clk/bimc_clk/");
	dtop_gen_init("/sys/kernel/debug/clk/snoc_clk/");
	dtop_gen_init("/sys/kernel/debug/clk/pnoc_clk/");

	if (usr_cl_opts.iptables_rules_routes == OPT_CHOSE) {
	printf("Datatop IP Tables, rules, routes\n");
	dtop_ip_table_init(usr_cl_opts.out_dir);
	if(0 != pthread_create(&tid, NULL, &dtop_ip_table_start_poll, NULL)) {
	printf("Unable to create capture_ip_tables_rules_routes thread\n");
	}
	}

	if (usr_cl_opts.print_cl == OPT_CHOSE) {
	dtop_poll(first_dpg_list);
	dtop_print_terminal(first_dpg_list);
	}

	if (usr_cl_opts.print_csv == OPT_CHOSE) {
	FILE *to_file = NULL;
	if ((dtop_open_writing_file(usr_cl_opts.file_name,
	&to_file)) == VALID) {
	printf("\nData being polled for %ld seconds.\n",
	usr_cl_opts.poll_time);
	if (dtop_poll_periodically(first_dpg_list, to_file)
	== FILE_ERROR) {
	fprintf(stderr, "err=%d: %s\n", errno,
	strerror(errno));
	dtop_close_file(to_file);
	deconstruct_dpgs(first_dpg_list);
	dtop_rem_linked_list(first_dpg_list);
	exit(EXIT_FAILURE);
	}
	dtop_close_file(to_file);
	} else {
	printf("File Can Not Be Opened\n");
	exit(EXIT_FAILURE);
	}
	}

	if (usr_cl_opts.snapshot_file) {
	if (dtop_print_system_snapshot(usr_cl_opts.snapshot_file)
	== FILE_ERROR) {
	fprintf(stderr, "err=%d: %s\n", errno,
	strerror(errno));
	deconstruct_dpgs(first_dpg_list);
	dtop_rem_linked_list(first_dpg_list);
	exit(EXIT_FAILURE);
	}
	}

	if (usr_cl_opts.print_cl == OPT_NOT_CHOSE &&
	usr_cl_opts.print_csv == OPT_NOT_CHOSE) {
	if ((!usr_cl_opts.snapshot_file)
	\|\| usr_cl_opts.poll_time_selected == POLL_TIME_SELECTED) {
	printf("\nData will now be polled for %ld seconds.\n",
	usr_cl_opts.poll_time);
	dtop_poll(first_dpg_list);
	sleep(usr_cl_opts.poll_time);
	dtop_poll(first_dpg_list);
	dtop_print_snapshot_diff(first_dpg_list);
	}
	}

	deconstruct_dpgs(first_dpg_list);
	dtop_rem_linked_list(first_dpg_list);
	return 0;
	}

	/**
	* @brief Adds each dpg as a node to a linked list.
	*
	* Called when a dpg is initialized.
	*
	* @param dpg A pointer to a data_point_gatherer struct which is to be added to the linked list.
	*/
	void dtop_register(struct dtop_data_point_gatherer *dpg)
	{
	if (dpg)
	first_dpg_list = dtop_add_linked_list(dpg, first_dpg_list);
	}