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OSProject.c
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OSProject.c
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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <dirent.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>
#include <time.h>
#include <sys/wait.h>
#include <stdbool.h>
#include <ctype.h>
#include <libgen.h>
#define MAX_FILES 1024
#define BUFFER_SIZE 4096
struct FileStat {
char *path;
int fileType;
long deviceID;
long inodeNumber;
long numHardLinks;
long ownerUserID;
long ownerGroupID;
long deviceIDSpecialFile;
long totalSize;
char *lastStatusChange;
char *lastFileAccess;
char *lastFileModification;
};
enum DifferenceType {
NO_DIFFERENCE,
FILE_ADDED,
FILE_DELETED,
FILE_RENAMED,
FILE_EDITED,
FILE_MOVED
};
struct Difference {
enum DifferenceType type;
char *path;
};
void readSnapshotFile(FILE *snapshotFile, struct FileStat *fileStats, int *fileCount) {
char line[BUFFER_SIZE];
while (fgets(line, BUFFER_SIZE, snapshotFile) != NULL) {
fileStats[*fileCount].path = strdup(line);
fileStats[*fileCount].fileType = atoi(fgets(line, BUFFER_SIZE, snapshotFile));
fileStats[*fileCount].deviceID = atol(fgets(line, BUFFER_SIZE, snapshotFile));
fileStats[*fileCount].inodeNumber = atol(fgets(line, BUFFER_SIZE, snapshotFile));
fileStats[*fileCount].numHardLinks = atol(fgets(line, BUFFER_SIZE, snapshotFile));
fileStats[*fileCount].ownerUserID = atol(fgets(line, BUFFER_SIZE, snapshotFile));
fileStats[*fileCount].ownerGroupID = atol(fgets(line, BUFFER_SIZE, snapshotFile));
fileStats[*fileCount].deviceIDSpecialFile = atol(fgets(line, BUFFER_SIZE, snapshotFile));
fileStats[*fileCount].totalSize = atol(fgets(line, BUFFER_SIZE, snapshotFile));
fileStats[*fileCount].lastStatusChange = strdup(fgets(line, BUFFER_SIZE, snapshotFile));
fileStats[*fileCount].lastFileAccess = strdup(fgets(line, BUFFER_SIZE, snapshotFile));
fileStats[*fileCount].lastFileModification = strdup(fgets(line, BUFFER_SIZE, snapshotFile));
(*fileCount)++;
}
}
bool isSameFile(struct FileStat *file1, struct FileStat *file2) {
// Compare all attributes except the path
return (file1->fileType == file2->fileType &&
file1->deviceID == file2->deviceID &&
file1->inodeNumber == file2->inodeNumber &&
file1->numHardLinks == file2->numHardLinks &&
file1->ownerUserID == file2->ownerUserID &&
file1->ownerGroupID == file2->ownerGroupID &&
file1->deviceIDSpecialFile == file2->deviceIDSpecialFile &&
file1->totalSize == file2->totalSize &&
strcmp(file1->lastStatusChange, file2->lastStatusChange) == 0 &&
strcmp(file1->lastFileAccess, file2->lastFileAccess) == 0 &&
strcmp(file1->lastFileModification, file2->lastFileModification) == 0);
}
void findDifferences(struct FileStat *newFileStat, int newFileCount, struct FileStat *existingFileStat, int existingFileCount) {
struct Difference differences[MAX_FILES];
int differenceCount = 0;
//Flag to mark existing files as matched. If not matched, it is deleted
bool existingMatched[existingFileCount];
memset(existingMatched, false, sizeof(existingMatched));
//Compare each file in the new snapshot with the files in the existing snapshot
for (int i = 0; i < newFileCount; i++) {
int found = 0;
for (int j = 0; j < existingFileCount; j++) {
if (strcmp(newFileStat[i].path, existingFileStat[j].path) == 0) {
found = 1;
// Check if file attributes other than path have changed
if (!isSameFile(&newFileStat[i], &existingFileStat[j])) {
differences[differenceCount].type = FILE_EDITED;
differences[differenceCount].path = newFileStat[i].path;
differenceCount++;
}
// Mark the existing file as matched
existingMatched[j] = true;
break;
}
}
// If the file is not found in the existing snapshot, it's either added, moved, or renamed
if (!found) {
int MoveOrRename = 0;
for(int j = 0; j < existingFileCount; j++)
{
//Check if inode number exists
if(newFileStat[i].inodeNumber == existingFileStat[j].inodeNumber)
{
//Extract filename after last '/'
char *newFileName = strrchr(newFileStat[i].path, '/');
char *existingFileName = strrchr(existingFileStat[j].path, '/');
if(strcmp(newFileName, existingFileName) == 0)
{
differences[differenceCount].type = FILE_MOVED;
differences[differenceCount].path = newFileStat[i].path;
existingMatched[j] = true;
}
else
{
differences[differenceCount].type = FILE_RENAMED;
differences[differenceCount].path = newFileStat[i].path;
existingMatched[j] = true;
}
MoveOrRename = 1;
break;
}
}
if(MoveOrRename == 0)
{
differences[differenceCount].type = FILE_ADDED;
differences[differenceCount].path = newFileStat[i].path;
}
differenceCount++;
}
}
// Any files remaining in the existing snapshot list are deleted
for (int i = 0; i < existingFileCount; i++) {
if (!existingMatched[i]) {
differences[differenceCount].type = FILE_DELETED;
differences[differenceCount].path = existingFileStat[i].path;
differenceCount++;
}
}
// Print the differences
for (int i = 0; i < differenceCount; i++) {
switch (differences[i].type) {
case FILE_ADDED:
printf("File added: %s", differences[i].path);
break;
case FILE_DELETED:
printf("File deleted: %s", differences[i].path);
break;
case FILE_EDITED:
printf("File edited: %s", differences[i].path);
break;
case FILE_MOVED:
printf("File moved: %s", differences[i].path);
break;
case FILE_RENAMED:
printf("File renamed: %s", differences[i].path);
break;
default:
break;
}
}
if (differenceCount == 0)
printf("No differences found.\n");
}
void compareSnapshots(const char *basePath, const char *newSnapshotPath, const char *existingSnapshotPath) {
FILE *newSnapshotFile = fopen(newSnapshotPath, "r");
if (newSnapshotFile == NULL) {
perror("Error opening new snapshot file");
return;
}
FILE *existingSnapshotFile = fopen(existingSnapshotPath, "r");
if (existingSnapshotFile == NULL) {
perror("Error opening existing snapshot file");
fclose(newSnapshotFile);
return;
}
struct FileStat newFileStat[MAX_FILES];
struct FileStat existingFileStat[MAX_FILES];
int newFileCount = 0;
int existingFileCount = 0;
readSnapshotFile(newSnapshotFile, newFileStat, &newFileCount);
readSnapshotFile(existingSnapshotFile, existingFileStat, &existingFileCount);
fclose(newSnapshotFile);
fclose(existingSnapshotFile);
findDifferences(newFileStat, newFileCount, existingFileStat, existingFileCount);
}
void traverseDirectory(const char *basePath, int outputFile, int pipeWrite) {
DIR *dir = opendir(basePath);
if (dir == NULL) {
perror("Error opening directory");
return;
}
struct dirent *entry;
struct stat fileStat;
while ((entry = readdir(dir)) != NULL) {
char path[1024];
snprintf(path, sizeof(path), "%s/%s", basePath, entry->d_name);
// To skip . .. as well as the snapshot files
char basePathCopy[1024];
strcpy(basePathCopy, basePath);
char SnapshotName[1024];
snprintf(SnapshotName, sizeof(SnapshotName), "SNAPSHOT_%s.txt", strtok(basePathCopy, "/"));
char tempSnapshotName[1024];
snprintf(tempSnapshotName, sizeof(tempSnapshotName), "SNAPSHOT_TEMP_%s.txt", strtok(basePathCopy, "/"));
if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0 ||
strcmp(entry->d_name, SnapshotName) == 0 || strcmp(entry->d_name, tempSnapshotName) == 0) {
continue;
}
if (stat(path, &fileStat) < 0) {
perror("Error getting file stat");
closedir(dir);
return;
}
if (S_ISDIR(fileStat.st_mode)) {
traverseDirectory(path, outputFile, pipeWrite);
} else {
// Write file information to output file
char buffer[4096];
snprintf(buffer, sizeof(buffer),
"%s\n%d\n%ld\n%ld\n%ld\n%ld\n%ld\n%ld\n%ld\n%s%s%s",
path, fileStat.st_mode, (long)fileStat.st_dev, (long)fileStat.st_ino, (long)fileStat.st_nlink,
(long)fileStat.st_uid, (long)fileStat.st_gid, (long)fileStat.st_rdev, (long)fileStat.st_size,
ctime(&fileStat.st_ctime), ctime(&fileStat.st_atime), ctime(&fileStat.st_mtime));
write(outputFile, buffer, strlen(buffer));
if(pipeWrite == -1) // Do not check for malicious content when just traversing to update snapshot
{
continue;
}
// Fork a child process to check each file
pid_t pid = fork();
if (pid == -1) {
perror("Error forking child process");
return;
} else if (pid == 0) { // Child process
close(outputFile);
pid_t verify_pid = fork();
if (verify_pid == -1) {
perror("Error forking verify process");
return;
} else if (verify_pid == 0) { // Child process for verification
close(pipeWrite);
// Execute verify_for_malicious.sh script to check for malicious content
execl("./verify_for_malicious.sh", "verify_for_malicious.sh", path, NULL);
perror("Error executing verify_for_malicious.sh");
exit(1);
} else { // Parent process
int status;
waitpid(verify_pid, &status, 0);
if (WIFEXITED(status)) {
if (WEXITSTATUS(status) == 0) { // Script returned zero -> file is safe
write(pipeWrite, "SAFE", strlen("SAFE") + 1);
} else { // Script returned non-zero -> file is malicious
write(pipeWrite, path, strlen(path) + 1);
}
} else {
perror("Script execution failed");
}
close(pipeWrite);
}
exit(0); // Exit this process after forking the verification process
}
}
}
closedir(dir);
}
int fileExists(const char *filePath) {
return access(filePath, F_OK) != -1;
}
int deleteFile(const char *filePath) {
return remove(filePath);
}
// Function to create directory if it doesn't exist
void createDirectory(const char *path) {
struct stat st;
if (stat(path, &st) == -1) {
if (mkdir(path, 0700) == -1) {
perror("Error creating directory");
exit(EXIT_FAILURE);
}
printf("Directory created: %s\n", path);
}
}
int main(int argc, char *argv[]) {
if (argc < 6 || strcmp(argv[1], "-o") != 0 || strcmp(argv[3], "-s") != 0) {
printf("Usage: %s -o Output_Directory -s Isolated_Space Directory_Path1 Directory_Path2 ... Directory_PathN\n", argv[0]);
return 1;
}
// Get the output directory and isolated space directory
char outputDirectory[256];
char isolatedSpace[256];
strcpy(outputDirectory, argv[2]);
strcat(outputDirectory, "/");
strcpy(isolatedSpace, argv[4]);
strcat(isolatedSpace, "/");
// Create the output directory and isolated space directory if they don't exist
createDirectory(outputDirectory);
createDirectory(isolatedSpace);
for(int i = 5; i < argc; i++)
{
pid_t pid = fork(); //Fork a child process
if(pid == -1)
{
perror("Error forking child process");
return 1;
}
else if(pid == 0)
{
char SnapshotFileName[256];
char SnapshotPath[2048];
snprintf(SnapshotFileName, sizeof(SnapshotFileName), "SNAPSHOT_%s.txt", argv[i]);
snprintf(SnapshotPath, sizeof(SnapshotPath), "%s%s", outputDirectory, SnapshotFileName);
char tempSnapshotFileName[256];
char tempSnapshotPath[2048];
snprintf(tempSnapshotFileName, sizeof(tempSnapshotFileName), "SNAPSHOT_TEMP_%s.txt", argv[i]);
snprintf(tempSnapshotPath, sizeof(tempSnapshotPath), "%s%s", outputDirectory, tempSnapshotFileName);
if(fileExists(SnapshotPath))
{
printf("Existing snapshot found for directory %s. Comparing with the new snapshot...\n", argv[i]);
int tempOutputFile = open(tempSnapshotPath, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR);
if(tempOutputFile < 0)
{
perror("Error creating temporary output file");
return 1;
}
traverseDirectory(argv[i], tempOutputFile, -1);
close(tempOutputFile);
compareSnapshots(argv[i], tempSnapshotPath, SnapshotPath);
if(deleteFile(SnapshotPath) != 0)
{
perror("Error deleting existing snapshot file");
return 1;
}
if(rename(tempSnapshotPath, SnapshotPath) != 0)
{
perror("Error renaming temporary snapshot file");
return 1;
}
printf("Snapshot for directory %s updated successfully.\n", argv[i]);
}
else
{
printf("No existing snapshot found for directory %s. Creating a new snapshot...\n", argv[i]);
int outputFile = open(SnapshotPath, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR);
if(outputFile < 0)
{
perror("Error creating output file");
return 1;
}
traverseDirectory(argv[i], outputFile, -1);
close(outputFile);
printf("Snapshot for directory %s created successfully.\n", argv[i]);
}
// Check files for malicious content
int pipeFD[2];
if (pipe(pipeFD) == -1) {
perror("Pipe creation failed");
return 1;
}
pid_t checkPid = fork();
if (checkPid == -1) {
perror("Error forking child process");
return 1;
} else if (checkPid == 0) { // Child process
close(pipeFD[0]); // Close the read end of the pipe
traverseDirectory(argv[i], -1, pipeFD[1]); // Do not write to any output file
close(pipeFD[1]); // Close the write end of the pipe
exit(0);
} else { // Parent process
close(pipeFD[1]); // Close the write end of the pipe
char result[256];
ssize_t bytesRead;
int maliciousFileCount = 0;
while ((bytesRead = read(pipeFD[0], result, sizeof(result))) > 0) {
if(strcmp(result, "SAFE") != 0)
{
maliciousFileCount++;
//Move to isolated space
char newFilePath[256];
snprintf(newFilePath, sizeof(newFilePath), "%s%s", isolatedSpace, basename(result));
if(rename(result, newFilePath) != 0)
{
perror("Error moving file to isolated space");
return 1;
}
}
}
close(pipeFD[0]); // Close the read end of the pipe
if (maliciousFileCount > 0) {
printf("Child process with PID %d found %d file(s) with malicious content\n", getpid(), maliciousFileCount);
} else {
printf("Child process with PID %d found no files with malicious content\n", getpid());
}
}
exit(0);
}
}
// Parent process waits for all child processes to finish
int status;
pid_t wpid;
while ((wpid = waitpid(-1, &status, 0)) > 0) {
if (WIFEXITED(status)) {
printf("Child process with PID %d exited with status %d\n", wpid, WEXITSTATUS(status));
} else {
printf("Child process with PID %d terminated abnormally\n", wpid);
}
}
return 0;
}