/**
* Send a string message through a socket.
* \param sock Socket descriptor for the socket to send the message through.
* \param buffer Buffer for buffering the message we send.
*/
void sendMessage(int sock, char* buffer)
{
int len = read(0,buffer,BUFFER_SIZE);
exitIfError(len,"Error reading from console");
len = write(sock, buffer, len);
exitIfError(len, "Error writing to socket");
}
Hashmap *newHashmap(size_t capacity) {
Hashmap *map = malloc(sizeof(Hashmap));
exitIfError(map == NULL, "mallocing during hashmap creation");
map->capacity = capacity;
map->entries = calloc(capacity, sizeof(MapEntry));
exitIfError(map->entries == NULL, "callocing during hashmap creation");
map->load = 0;
return map;
}
/**
* Receive a string message through a socket.
* \param sock Socket descriptor for the socket to receive the message through.
* \param buffer Buffer for buffering the message we receive.
*/
int receiveMessage(int sock, char* buffer)
{
int len = read(sock,buffer,BUFFER_SIZE);
exitIfError(len,"Error reading from socket");
if (len == 0)
return -1;
len = write(1, buffer, len);
exitIfError(len, "Error writing to console");
return 0;
}
void growHashmap(Hashmap *map, size_t newCapacity) {
map->entries = realloc(map->entries, newCapacity * sizeof(MapEntry));
exitIfError(map->entries == NULL, "reallocing during hashmap resize");
memset(map->entries + map->capacity, 0, (newCapacity - map->capacity) * sizeof(MapEntry));
size_t currIndex;
for (currIndex = 0; currIndex < map->capacity; currIndex++) {
MapEntry *oldEntry = map->entries + currIndex;
if (oldEntry->key == NULL) {
continue;
}
size_t newIndex = *(size_t *)oldEntry->key % newCapacity;
if (newIndex == currIndex) {
continue;
}
MapEntry *newEntry = map->entries + newIndex;
while (newEntry->key != NULL) {
newEntry++;
if (newEntry >= map->entries + newCapacity) {
newEntry = map->entries;
}
}
newEntry->key = oldEntry->key;
newEntry->value = oldEntry->value;
oldEntry->key = NULL;
oldEntry->value = NULL;
}
map->capacity = newCapacity;
}
void createIndex(Hashmap *map, DIR *directory) {
if (directory == NULL) {
printf("ERROR");
}
struct dirent *ent;
while ((ent = readdir(directory)) != NULL) {
if (strcmp(ent->d_name, ".") == 0 || strcmp(ent->d_name, "..") == 0) {
continue;
}
FILE *file = fopen(ent->d_name, "r");
exitIfError(ferror(file), "opening file during indexing");
char *hash = hashFile(file);
exitIfError(fclose(file) == EOF, "closing file during indexing");
putInHashmap(map, hash, ent->d_name);
}
}
/**
* Starts normal communication through global socket \a sock.
*/
void communicate()
{
char buffer[BUFFER_SIZE];
struct pollfd fds[FDCOUNT];
memset(fds, 0, sizeof(fds));
fds[0].fd = 0;
fds[1].fd = sock;
fds[0].events=fds[1].events = POLLIN;
int result;
for (;;)
{
result = poll(fds,FDCOUNT,-1);
exitIfError(result, "Error on polling");
if (result>0)
{
if (fds[1].revents & POLLHUP)
break;
if (fds[0].revents & POLLIN)
sendMessage(sock, buffer);
if (fds[1].revents & POLLIN)
if (-1 == receiveMessage(sock, buffer))
break;
}
}
}
/**
* Create a client and connect to localhost on the specified port.
* \param host The host name or ip address to connect to.
* \param port The port to connect to.
*/
void client(char * host, char* port)
{
#ifdef DEBUG
puts("Client start requested.");
#endif
//resolve domain and port name and connect to target
struct addrinfo hints, *res, *rp;
memset(&hints, 0, sizeof(hints));
hints.ai_family = AF_INET;
hints.ai_socktype = SOCK_STREAM;
if (0 != getaddrinfo(host, port, &hints, &res))
{
fprintf(stderr, "Error resolving address \"%s\". Exiting.\n", host);
exit(1);
}
//evaluate results
for (rp = res; rp != NULL; rp = rp->ai_next)
{
sock = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
if (sock == -1)
continue;
if (connect(sock, rp->ai_addr, rp->ai_addrlen) == 0)
break; /* Success */
close(sock);
sock = -1;
}
freeaddrinfo(res);
exitIfError(sock,"Error connecting to socket");
//send messages
communicate();
}
char *hashFile(FILE *file) {
unsigned char *md_value = malloc(HASH_LENGTH);
exitIfError(md_value == NULL, "mallocing during file hashing");
EVP_MD_CTX mdctx;
EVP_MD_CTX_init(&mdctx);
const EVP_MD *md = EVP_sha256();
EVP_DigestInit_ex(&mdctx, md, NULL);
int bytes;
unsigned char data[4096];
while ((bytes = fread(data, 1, 4096, file)) != 0) {
exitIfError(ferror(file), "reading data from file during hashing");
EVP_DigestUpdate(&mdctx, data, bytes);
}
EVP_DigestFinal_ex(&mdctx, md_value, NULL);
EVP_MD_CTX_cleanup(&mdctx);
return md_value;
}
/**
* The main function of the program.
* \param argc The argument count
* \param argv The command line arguments
*/
int main (int argc, char * argv[])
{
//register signal handlers
signal( SIGTERM, signalHandler);
signal( SIGINT, signalHandler);
//register cleanUp function
int result = atexit(cleanUpOnExit);
exitIfError(result, "Error registering exit function:");
parseCmdLineArguments(argc, argv);
}
/**
* Starts a server listing on a specified port
* \param port_s The Port or service name to listen on
*/
void server(char * port_s)
{
int port = resolvePort(port_s);
if (port == -1)
exit(1);
//create socket
sock = socket(AF_INET,SOCK_STREAM, 0);
exitIfError(sock, "Error creating socket");
//stop socket from blocking the port after disconnecting
int sockopt = 1;
int result = setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &sockopt, sizeof(sockopt));
exitIfError(result, "Error setting socket options");
//bind to port
struct sockaddr_in localAddr, remoteAddr;
localAddr.sin_family = AF_INET;
localAddr.sin_port = port;
//on all interfaces
localAddr.sin_addr.s_addr = INADDR_ANY;
result = bind(sock, (struct sockaddr*)&localAddr, sizeof(localAddr));
exitIfError(result, "Error binding to port");
//start listening
result = listen(sock, 1); // only one client allowed
exitIfError(result, "Error listening");
//accept connections
socklen_t remoteAddrLength = sizeof(remoteAddr);
int communicationSocket = accept(sock, (struct sockaddr*) &remoteAddr, &remoteAddrLength);
exitIfError(communicationSocket, "Error accepting connection");
//replace listening socket with communicationSocket, so there is only one socket to close on catching signals etc.
close(sock);
sock = communicationSocket;
communicate();
}
