static char *
locate_next_exec(const char *path, const char *first_dir, const char *name, const char* ignore_prefix)
{
struct buffer buf[1];
size_t first_dir_len, ignore_prefix_len;
const char *dir_start;
bool more, found;
enum { BEFORE_FIRST_DIR, SEARCH_SECOND_DIR } state;
first_dir_len = strlen(first_dir);
if (ignore_prefix != NULL) {
ignore_prefix_len = strlen(ignore_prefix);
} else {
ignore_prefix_len = 0;
}
buffer_init(buf);
dir_start = path;
more = true;
found = false;
state = BEFORE_FIRST_DIR;
for (;;) {
const char *dir_end = strchr(dir_start, ':');
size_t dir_len;
if (dir_end == NULL) {
more = false;
dir_end = strchr(path, '\0');
}
dir_len = dir_end - dir_start;
if (dir_start[0] != '/'
&& !(dir_len == 1 && *dir_start == '.'))
{
build_location(dir_start, dir_len, NULL, buf);
warning("PATH component is not absolute path: %s",
buf->ptr);
} else if (state == BEFORE_FIRST_DIR) {
bool found = false;
if (first_dir_len == dir_len) {
if (0 == memcmp(dir_start, first_dir,
first_dir_len))
{
found = true;
}
}
if (found) {
build_location(dir_start, dir_len, name, buf);
if (!is_executable(buf->ptr)) {
fatal_error("Failed to locate executable regular file '%s' in %s", name, first_dir);
}
state = SEARCH_SECOND_DIR;
}
} else if (state == SEARCH_SECOND_DIR) {
bool skip = false;
if (ignore_prefix != NULL
&& dir_len >= ignore_prefix_len)
{
if (0 == memcmp(dir_start, ignore_prefix,
ignore_prefix_len))
{
skip = (dir_len == ignore_prefix_len)
|| (dir_start[ignore_prefix_len]
== '/');
}
}
if (!skip) {
build_location(dir_start, dir_len, name, buf);
if (is_executable(buf->ptr)) {
found = true;
break;
}
}
} else {
assert(false);
}
if (more) {
dir_start = dir_end + 1;
continue;
}
break;
}
if (!found) {
fatal_error("Failed to locate real executable '%s' in %s", name, path);
}
return buffer_forget(buf, strlen(buf->ptr) + 1);
}
int main(){
struct sockaddr_in serv;
memset(&serv, 0, sizeof(serv));
int option = 0, sokk = 0, ran_loc = 0, id = 0, indic = 0;
char location[101] = "", query[50] = "", answer[250] = "";
struct info arr[6];
FILE *idfile = NULL;
socklen_t temp_size;
// create array of different locations
if(create_list(arr, 6) != 0){
printf("An error happened while creating the locations\n");
return -1;
}
// pick a location randomly to use as current location
srand(time(NULL));
ran_loc = rand() % 6;
// open a socket, declare what kind it is and save IP and port into sockaddr_in structure
sokk = socket(AF_INET, SOCK_DGRAM, 0);
serv.sin_family = AF_INET;
serv.sin_port = htons(7000);
inet_pton(AF_INET, "127.0.0.1" /*"80.239.229.217"*/, &serv.sin_addr);
// check if this client has already an ID assigned
idfile = fopen("ID_file", "r");
// no ID assigned, fopens fails because the file doesn't exist
if(idfile == NULL){
perror("This client has not yet assigned an ID:");
// build a string containing the location information
if(build_location(location, arr[ran_loc], id, indic, 0, NULL) != 0){
printf("Error while building the string to be sent to the server, idfile = NULL\n");
return -1;
}
// send the string to the server containing zero as ID
if(strlen(location) != sendto(sokk, location, strlen(location), 0, (struct sockaddr *) &serv, sizeof(serv))){
perror("some error happened when sending zero as ID, the location information could not be sent properly (id is 0):");
return -1;
}
// read from the server what ID it assigns to this client and save it into a file
temp_size = sizeof(serv);
if(recvfrom(sokk, &id, sizeof(int), 0, (struct sockaddr*)&serv, &temp_size) == -1){ // modify this in order to decode properly the answer from server
perror("some error happened at reading the ID sent by the server:");
return -1;
}
idfile = fopen("ID_file", "w");
if(idfile == NULL){
perror("An error happened when creating the ID_file in order to write the newly assigned ID:");
return -1;
}
if(fwrite(&id, sizeof(id), 1, idfile) != 1){
printf("The newly assigned ID could not be written into the file\n");
return -1;
}
}
// this client has already an ID, read it from the file and store it in variable id
else{
if(fread(&id, sizeof(int), 1, idfile) != 1){
printf("some error happened at reading the ID stored in the file\n");
return -1;
}
printf("The id read from the file is: %d\n", id);
// indicator to specify that an ID has been assigned
indic++;
// build a string containing the location information
if(build_location(location, arr[ran_loc], id, indic, 0, NULL) != 0){
printf("Error while building the string to be sent to the server, ID_file exists\n");
return -1;
}
printf("The string to be sent to the server as initial location is (with exiting idfile): %s\n", location);
// send location information to the server
ssize_t first_sent = sendto(sokk, location, strlen(location), 0, (struct sockaddr *) &serv, sizeof(serv));
if(strlen(location) != first_sent){
perror("some error happened while sending location info to the server, the location information could not be sent properly:");
return -1;
}
printf("the bytes sent to the server, idfile exists is: %d\n", first_sent);
}
// greet the user and ask what operation s/he wants
printf("Please select the number from the following options that best suits your request\n");
printf("1) I have a name and want to get the rest of the information\n");
printf("2) I have an email address and want to get the rest of the information\n");
for( ; ; ){
scanf("%d", &option);
if(option == 1){
// ask the user to input the information s/he has
printf("Please write the name from which you want to get information and press enter\n");
scanf("%s", query);
// build the query string with name as parameter
if(build_location(location, arr[ran_loc], id, indic, option, query) != 0){
printf("Error while creating string for query by name\n");
return -1;
}
printf("The string just built is (for, option 1): %s", location);
break;
}
else if(option == 2){
// ask the user to input the information s/he has
printf("Please write the email address from which you want to get information and press enter\n");
scanf("%s", query);
// build the query string with email as parameter
if(build_location(location, arr[ran_loc], id, indic, option, query) != 0){
printf("Error while creating string for query by email\n");
return -1;
}
break;
}
else
printf("The option you provided is invalid, please indicate the desired option by its number (1 or 2)");
}
// send the information to the server
if(strlen(location) != sendto(sokk, location, strlen(location), 0, (struct sockaddr *) &serv, sizeof(serv))){
printf("some error happened, the query could not be sent to the server\n");
return -1;
}
printf("All good, waiting for the server query answer\n");
// read the answer from the server
temp_size = sizeof(serv);
if(recvfrom(sokk, answer, sizeof(answer), 0, (struct sockaddr *) &serv, &temp_size) == -1){
perror("some error happened at reading the answer of the query\n");
return -1;
}
// display the info of the query to the user
printf("%s\n", answer);
// close everything and exit
close(sokk);
return 0;
}
