[nethist] Add skeleton of nethist application.

nethist/Makefile

+BIN=nethist
+SRC=nethist.c
+CC=gcc
+FLAGS=-Wall -Wextra -pedantic -std=gnu99 -O0 -g
+LIBS=
+
+$(BIN): $(SRC)
+	$(CC) $(FLAGS) $(LIBS) -o $(BIN) $(SRC)
+
+clean:
+	rm $(BIN)
+

nethist/nethist.c

+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+
+#define BUFFSIZE 512
+#define SNAPSHOT_COUNT 100
+#define SLEEP_TIME_USEC 3000000
+#define SNIFF_FILE_NET "/proc/net/dev"
+
+#define MAX_LEN_INTERFACE_NAME 20
+#define MAX_LEN_INTERFACE_LIST 20
+
+struct network_configuration {
+	char interfaces[MAX_LEN_INTERFACE_LIST];
+	size_t interfaces_cnt;
+};
+
+typedef struct {
+	struct network_configuration network;
+} configuration;
+
+configuration g_config;
+
+struct network_snapshot {
+	unsigned long long interface[MAX_LEN_INTERFACE_LIST];
+};
+
+typedef struct {
+	struct network_snapshot network;
+	//struct cpu_snapshot cpu; //etc. etc.
+} snapshot;
+
+
+static void network_init_snapshot(struct network_snapshot *snapshot) {
+	for (size_t i = 0; i < MAX_LEN_INTERFACE_LIST; i++) {
+		snapshot->interface[i] = 0;
+	}
+}
+
+static bool network_init_global() {
+	char buffer[BUFFSIZE];
+	FILE *f = fopen(SNIFF_FILE_NET, "r");
+	if (f == NULL) return false;
+
+	for (size_t i = 0; i < 2; i++) { //skip first 2 lines
+		if (fgets(buffer, BUFFSIZE, f) == NULL) {
+			fclose(f);
+			return false;
+		}
+	}
+
+	g_config.network.interfaces_cnt = 0;
+
+	while (fgets(buffer, BUFFSIZE, f) != NULL) {
+		sscanf(buffer, "%20s", &g_config.network.interfaces[g_config.network.interfaces_cnt++]);
+	}
+
+	fclose(f);
+
+	return true;
+}
+
+static bool network_take_snapshot(struct network_snapshot *snap) {
+	char buffer[BUFFSIZE];
+	FILE *f = fopen(SNIFF_FILE_NET, "r");
+	if (f == NULL) return false;
+
+	for (size_t i = 0; i < 2; i++) { //skip first 2 lines
+		if (fgets(buffer, BUFFSIZE, f) == NULL) {
+			fclose(f);
+			return false;
+		}
+	}
+
+	while (fgets(buffer, BUFFSIZE, f) != NULL) {
+
+	}
+
+
+	fclose(f);
+
+	return true;
+}
+
+static void init(snapshot *snapshots) {
+	for (size_t i = 0; i < SNAPSHOT_COUNT; i++) {
+		network_init_snapshot(&(snapshots[i].network));
+	}
+
+	network_init_global();
+}
+
+static void take_snapshot(snapshot *snap) {
+	network_take_snapshot(&(snap->network));
+}
+
+int main(int argc, char **argv) {
+	(void) argc; (void) argv;
+
+	snapshot snapshots[SNAPSHOT_COUNT];
+	size_t write_to = 0;
+
+	init(snapshots);
+
+	while(true) {
+		/*
+		 * Using modulo is possibly not good idea - we expect very, very long runtime
+		 */
+		if (write_to == SNAPSHOT_COUNT) {
+			write_to = 0;
+		}
+
+		take_snapshot(&(snapshots[write_to]));
+
+
+		write_to++;
+	}
+
+
+	return 0;
+}