antivirus.c

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include "dirent.h"

#define ARGS_COUNT 2 // Not including the program name
#define BUFFER 1000

void writeLog();
void chooseAndScan(char** argv);
void printWelcome(char** argv);
void checkArgs(int argc);
void normalScan(char* folderToCheck, char* virusSign, char** filesList, int filesNum);
void quickScan(char* folderToCheck, char* virusSign, char** filesList, int filesNum);
int getFiles(char* folderDirectory, char** filesList);
bool isInfected(char* fileToCheck, char* virusSign, double scanFrom, double scanTo);

enum scanTypes
{
    normalScanType,
    quickScanType
} scanType;

char logBuilder[BUFFER] = { 0 };

int main(int argc, char** argv)
{
    checkArgs(argc);
    /*
    * argv[0] = Program Name
    * argv[1] = Folder to scan
    * argv[2] = Virus signature
    */

    printWelcome(argv);

    chooseAndScan(argv);

    writeLog();


    getchar();
    return 0;

}
/// <summary>
/// Checks if the arguments of the program correctly
/// </summary>
/// <param name="argc">Number of the given arguments</param>
void checkArgs(int argc)
{
    if (argc != ARGS_COUNT + 1)
    {
        printf("Invalid execution.\nUsage:\n"
            "> Antivirus <Folder_to_scan [directory]> <Virus_signature [directory]>\n");

        getchar();
        exit(1); // Stop program
    }
}
int getFiles(char* folderDirectory, char** filesList)
{
    DIR* d = 0;
    int i = 0;
    struct dirent* dir = 0;

    d = opendir(folderDirectory);

    if (d == NULL)
    {
        printf("Error opening directory: %s\n", folderDirectory);

        exit(1); // Stop program
    }

    while ((dir = readdir(d)) != NULL)
    {
        if (strcmp(dir->d_name, ".") &&
            strcmp(dir->d_name, "..") &&
            dir->d_type != DT_DIR)
        {
            filesList = (char**)realloc(filesList, sizeof(char*) * (i + 1));
            if (filesList == NULL)
            {
                printf("Unsuccessful realloc!\n");
                exit(1);
            }
            filesList[i] = (char*)malloc(sizeof(char) * (dir->d_namlen + 1));
            if (filesList[i] == NULL)
            {
                while (i)
                {
                    i--;
                    free(filesList[i]);
                }
                free(filesList);
                printf("Unsuccessful malloc!\n");
                exit(1);
            }

            strcpy(filesList[i], folderDirectory);
            strcat(filesList[i], "/");
            strcat(filesList[i], dir->d_name);

            i++;
        }
    }
    closedir(d);

    return i;
}
bool isInfected(char* fileToCheck, char* virusSign, double scanFrom, double scanTo)
{
    int checkData = 0, virusData = 0;
    double fileSize = 0;

    FILE* checkFile = fopen(fileToCheck, "rb");
    if (checkFile == NULL)
    {
        printf("Error opening file: %s\n", fileToCheck);

        exit(1); // Stop program
    }

    FILE* virusFile = fopen(virusSign, "rb");
    if (virusFile == NULL)
    {
        fclose(checkFile);
        printf("Error opening file: %s\n", virusSign);

        exit(1); // Stop program
    }

    fseek(checkFile, 0L, SEEK_END);
    fileSize = ftell(checkFile); // get file size
    fseek(checkFile, 0L, SEEK_SET);
    // 0.2 - 20% || 0.8 - 80% || 1 = 100%
    // from 0 to 0.2 -> first 20%
    // from 0.8 to 1 -> last 20% (1 - 8 = 0.2 ~ 20%)
    while ((checkData = fgetc(checkFile)) != EOF) {
        if ((fileSize * scanFrom <= ftell(checkFile)) && (fileSize * scanTo >= ftell(checkFile))) // scan only in the given range
        {
            virusData = fgetc(virusFile);
            if (virusData == EOF) // Check if the virus sign FULLY exists in the given file to check
            {
                fclose(checkFile);
                fclose(virusFile);

                return true;
            }
            else if (virusData != checkData) // If the virus data doesn't equals to the given file data, "reset" the data "counter"
            {
                fseek(virusFile, 0, SEEK_SET); // start over the virus data
            }
        }
    }

    fclose(checkFile);
    fclose(virusFile);

    return false;
}
void normalScan(char* folderToCheck, char* virusSign, char** filesList, int filesNum)
{
    int i = 0;

    strcat(logBuilder, "Reuslts:\n");

    printf("Scanning:\n");
    for (i = 0; i < filesNum; i++)
    {
        strcat(logBuilder, filesList[i]);
        if (isInfected(filesList[i], virusSign, 0, 1))
        {
            strcat(logBuilder, " Infected!\n");
            printf("%s - Infected!\n", filesList[i]);
        }
        else
        {
            strcat(logBuilder, " Clean\n");
            printf("%s - Clean\n", filesList[i]);
        }
    }

}
void quickScan(char* folderToCheck, char* virusSign, char** filesList, int filesNum)
{
    int i = 0;

    printf("Scanning:\n");
    for (i = 0; i < filesNum; i++)
    {
        printf("%s", filesList[i]);
        if (isInfected(filesList[i], virusSign, 0, 0.2))
        {
            printf("%s - Infected! (first 20%%)\n", filesList[i]);
        }
        else if (isInfected(filesList[i], virusSign, 0.8, 1))
        {
            printf("%s - Infected! (last 20%%)\n", filesList[i]);
        }
        else if (isInfected(filesList[i], virusSign, 0, 1))
        {
            printf("%s - Infected!\n", filesList[i]);
        }
        else
        {
            printf("%s - Clean\n", filesList[i]);
        }
    }
}
void printWelcome(char** argv)
{
    printf("Welcome to my Virus Scan!\n\n");

    printf("Folder to scan: %s\n"
           "Virus signature: %s\n\n", argv[1], argv[2]);

    strcat(logBuilder, "Anti-virus began! Welcome!\n\n");
    strcat(logBuilder, "Folder to scan:\n");
    strcat(logBuilder, argv[1]);
    strcat(logBuilder, "\nVirus signature:\n");
    strcat(logBuilder, argv[2]);
    strcat(logBuilder, "\n\n");
}
void chooseAndScan(char** argv)
{
    char** filesList = (char**)malloc(0);
    int filesNum = getFiles(argv[1], filesList);

    printf("Press 0 for a normal scan or any other key for quick scan: ");
    scanf("%d", &scanType);
    getchar();


    strcat(logBuilder, "Scanning option:\n");
    printf("Scanning began...\n"
        "This process may take several minutes...\n\n");

    switch (scanType)
    {
        case normalScanType:
        {
            strcat(logBuilder, "Normal Scan\n\n");
            normalScan(argv[1], argv[2], filesList, filesNum);
            break;
        }
        default: // quickScanType
        {
            strcat(logBuilder, "Quick Scan\n\n");
            quickScan(argv[1], argv[2], filesList, filesNum);
            break;
        }
    }
    printf("Scan Completed.\n");
}
void writeLog()
{
    FILE* fileLog = NULL;

    switch (scanType)
    {
        case normalScanType:
            fileLog = fopen("LogExample.txt", "w+");
            break;
        default:
            fileLog = fopen("LogExampleQuick.txt", "w+");
            break;
    }
    if (fileLog == NULL)
    {
        printf("Error to open the file\n");
        exit(1);
    }
    fputs(logBuilder, fileLog);

    fclose(fileLog);
}