uni/inf1060/hw2/ruterdrift.c

#include "argparser.h"

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <ctype.h>
#include <unistd.h>
#include <signal.h>
#include <readline/readline.h>
#include <readline/history.h>

struct router
{
	unsigned char id;
	char model[256];

	struct flag
	{
		int active;
		int wireless;
		int ghz5;
		int changenum;
	} flag;
};

void router_print(struct router *r)
{
	printf("ID: %i | Modell: %s\n", r->id, r->model);
	printf("\tAktiv: %i | Trådløs: %i | 5GHz: %i | Endringsnummer: %u\n",
		r->flag.active,
		r->flag.wireless,
		r->flag.ghz5,
		r->flag.changenum);
}

void router_read(struct router *r, FILE *f)
{
	unsigned char modellen;
	unsigned char flag;

	fread(&r->id, sizeof(r->id), 1, f);
	fread(&flag, sizeof(flag), 1, f);
	fread(&modellen, sizeof(modellen), 1, f);

	fread(&r->model, sizeof(*r->model), modellen - 1, f);
	r->model[modellen - 1] = '\0';

	r->flag.active = !!(flag & 0b00000001);
	r->flag.wireless = !!(flag & 0b00000010);
	r->flag.ghz5 = !!(flag & 0b00000100);
	r->flag.changenum = (flag & 0b11110000) >> 4;

	while (fgetc(f) != '\n');
}

void router_write(struct router *r, FILE *f)
{
	unsigned char id = r->id;
	unsigned char modellen = strlen(r->model) + 1;
	char* model = r->model;
	unsigned char flag = 0;

	if (r->flag.active)
		flag |= 0b00000001;
	if (r->flag.wireless)
		flag |= 0b00000010;
	if (r->flag.ghz5)
		flag |= 0b00000100;

	flag |= ((r->flag.changenum << 4) & 0b11110000);

	fwrite(&id, sizeof(id),1, f);
	fwrite(&flag, sizeof(flag), 1, f);
	fwrite(&modellen, sizeof(modellen), 1, f);
	fwrite(model, sizeof(*model), modellen - 1, f);

	char nl = '\n';
	fwrite(&nl, sizeof(nl), 1, f);
}

// Our array of router pointers
static struct router *routers[256];

// The biggest ID in the routers array
static unsigned char maxid;

// The name of the file we read from and write to
static char *filename;

void read_routers()
{
	FILE *f;
	if ((f = fopen(filename, "r")) == NULL)
	{
		perror(filename);
		exit(1);
	}

	memset(routers, 0, sizeof(NULL));

	int nrouters;
	fread(&nrouters, sizeof(nrouters), 1, f);

	// Skip to after newline
	while (fgetc(f) != '\n');

	for (int i = 0; i < nrouters; ++i)
	{
		struct router *r = malloc(sizeof(*r));
		router_read(r, f);
		routers[r->id] = r;
		if (r->id > maxid)
			maxid = r->id;
	}

	fclose(f);
}

void write_routers()
{
	FILE *f;
	if ((f = fopen(filename, "w")) == NULL)
	{
		perror(filename);
		exit(1);
	}

	char nl = '\n';

	int nrouters = 0;
	for (int i = 0; i <= maxid; ++i)
	{
		if (routers[i] != NULL)
			nrouters += 1;
	}

	fwrite(&nrouters, sizeof(nrouters), 1, f);
	fwrite(&nl, sizeof(nl), 1, f);

	for (int i = 0; i <= maxid; ++i)
	{
		if (routers[i] == NULL) continue;
		router_write(routers[i], f);
	}

	fclose(f);
}

void cmd_help()
{
	printf("\thelp:\n\t\tShow this help text\n\n");

	printf("\tprint [router id]:\n");
	printf("\t\tPrint a router. If no router ID is provided, all will be printed.\n\n");

	printf("\tchange <router id> <key> <val>:\n\t\tChange a value\n");
	printf("\t\tkeys:\n");
	printf("\t\t\tactive (int)\n");
	printf("\t\t\twireless (int)\n");
	printf("\t\t\t5ghz (int)\n");
	printf("\t\t\tmodel (string)\n\n");

	printf("\tcreate <active> <wireless> <5ghz> <model> [id]:\n");
	printf("\t\tCreate a new router.\n\n");

	printf("\tdelete <router id>:\n");
	printf("\t\tDelete a router\n\n");

	printf("\tq:\n\t\tExit\n");
	printf("\n");
}

void cmd_print(char *router_id)
{
	if (router_id == NULL)
	{
		for (int i = 0; i <= maxid; ++i)
		{
			if (routers[i] == NULL) continue;
			struct router *r = routers[i];
			if (r == NULL)
				continue;

			router_print(r);
			printf("\n");
		}
	}
	else
	{
		int rid = atoi(router_id);
		struct router *r;
		if ((r = routers[rid]) == NULL)
		{
			fprintf(stderr, "Unknown router: %s\n", router_id);
			return;
		}

		router_print(r);
		printf("\n");
	}
}

void cmd_change(char *router_id, char* key, char* val)
{
	if (router_id == NULL || key == NULL || val == NULL)
	{
		printf("Not enough arguments.\n");
		return;
	}

	int rid = atoi(router_id);
	struct router *r;
	if ((r = routers[rid]) == NULL)
	{
		fprintf(stderr, "Unknown router: %s\n", router_id);
		return;
	}

	if (r->flag.changenum == 15)
	{
		fprintf(stderr, "Router %i has been changed 15 times already\n", rid);
		return;
	}

	if (strcmp(key, "active") == 0)
		r->flag.active = !!atoi(val);
	else if (strcmp(key, "wireless") == 0)
		r->flag.wireless = !!atoi(val);
	else if (strcmp(key, "5ghz") == 0)
		r->flag.ghz5 = !!atoi(val);
	else if (strcmp(key, "model") == 0)
		if (strlen(val) > 254)
		{
			fprintf(stderr, "Too long model name\n");
			return;
		}
		else
		{
			strncpy(r->model, val, 256);
		}
	else
	{
		fprintf(stderr, "Unknown key: %s\n", key);
		return;
	}

	r->flag.changenum += 1;
}

void cmd_create(char *active, char *wireless, char *ghz5, char *model, char *id)
{
	if (active == NULL || wireless == NULL || ghz5 == NULL || model == NULL)
	{
		printf("Not enough arguments.\n");
		return;
	}

	if (strlen(model) > 254)
	{
		fprintf(stderr, "Too long model name\n");
		return;
	}

	struct router *r = malloc(sizeof(*r));

	unsigned char rid;
   
	if (id == NULL)
	{
		if ((int)maxid + 1 > 255)
		{
			fprintf(stderr, "ID %i is too big.\n", (int)maxid + 1);
			return;
		}

		maxid += 1;
		rid = maxid;
	}
	else
	{
		int irid = atoi(id);
		if (irid > 255)
		{
			fprintf(stderr, "ID %i is too big.\n", irid);
			return;
		}
		rid = (unsigned char)irid;

		if (routers[rid] != 0)
		{
			fprintf(stderr, "Router with ID %i alreday exists.\n", rid);
			return;
		}

		if (rid > maxid)
			maxid = rid;
	}

	r->flag.active = !!atoi(active);
	r->flag.wireless = !!atoi(wireless);
	r->flag.ghz5 = !!atoi(ghz5);
	r->flag.changenum = 0;
	r->id = rid;
	strncpy(r->model, model, 256);

	routers[rid] = r;
}

void cmd_delete(char *router_id)
{
	if (router_id == NULL)
	{
		printf("Not enough arguments.\n");
		return;
	}

	int rid = atoi(router_id);
	struct router *r = routers[rid];
	if (r == NULL)
	{
		fprintf(stderr, "Unknown router: %s\n", router_id);
		return;
	}

	free(r);
	routers[rid] = NULL;

	while (routers[maxid] == NULL) maxid -= 1;
}

void cmd_exit()
{
	clear_history();

	// Write routers to disk
	printf("Writing changes to disk...\n");
	write_routers();

	// Free memory
	for (int i = 0; i < 256; ++i)
	{
		struct router *r = routers[i];
		if (r == NULL)
			continue;

		free(r);
	}

	exit(0);
}

int eval(char *str)
{
	char *argv[7];
	argparser_parse(argv, 6, str);

	char *cmd = argv[0];

	if (argv[0] == NULL)
		return 0;

	if (strcmp(cmd, "help") == 0)
	{
		cmd_help();
	}
	else if (strcmp(cmd, "print") == 0)
	{
		cmd_print(argv[1]);
	}
	else if (strcmp(cmd, "change") == 0)
	{
		cmd_change(argv[1], argv[2], argv[3]);
	}
	else if (strcmp(cmd, "create") == 0)
	{
		cmd_create(argv[1], argv[2], argv[3], argv[4], argv[5]);
	}
	else if (strcmp(cmd, "delete") == 0)
	{
		cmd_delete(argv[1]);
	}
	else if (strcmp(cmd, "q") == 0)
	{
		free(str);
		cmd_exit();
	}
	else
	{
		printf("Unknown command: '%s'. Type 'help' for help.\n", cmd);
	}

	free(str);
	return 1;
}

void term(int signum)
{
	printf("\n"); // We don't want to print a message on the same line as ^C
	cmd_exit();
}

int main(int argc, char **argv)
{
	// SIGTERM and SIGINT listener
	struct sigaction action;
	memset(&action, 0, sizeof(action));
	action.sa_handler = term;
	sigaction(SIGTERM, &action, NULL);
	sigaction(SIGINT, &action, NULL);

	if (argc != 2)
	{
		fprintf(stderr, "Usage: %s <file>\n", argv[0]);
		return 1;
	}

	filename = argv[1];
	read_routers();

	while (1)
	{
		char *str = readline("> ");
		if (!str) continue;
		add_history(str);
		eval(str);
	}

	return 0;
}