void mcast_accept_msg(struct state_info info) {
char diag[200];
GQueue *waiting_req_q = (*info.my_lift_number == LIFT_1) ? info.waiting_req_q1 : info.waiting_req_q2;
int len = g_queue_get_length(waiting_req_q);
// diag_msg(info.mstrtid, info.mytid, "*** 0");
int *tids = malloc(len * sizeof(int));
int i = 0;
sprintf(diag, "*** %d processes awaiting accepts", g_queue_get_length(info.waiting_req_q));
diag_msg(info.mstrtid, info.mytid, diag);
while (!g_queue_is_empty(waiting_req_q)) {
int *tid = g_queue_pop_head(waiting_req_q);
int *sender_weight_ptr = g_hash_table_lookup(info.skiers_weights, tid);
int *lift_free = (*info.my_lift_number == LIFT_1) ? info.lift1_free : info.lift2_free;
*lift_free -= *sender_weight_ptr;
tids[i] = *tid;
i++;
sprintf(diag, "*** mcast MSG_ACCEPT to %d [weight=%d]", *tid, *sender_weight_ptr);
diag_msg(info.mstrtid, info.mytid, diag);
}
*info.local_clock += 1;
int tag = MSG_ACCEPT;
pvm_initsend(PvmDataDefault);
pvm_pkint(&tag, 1, 1);
pvm_pkint(&info.mytid, 1, 1);
pvm_pkint(info.local_clock, 1, 1);
pvm_mcast(tids, len, tag);
sprintf(diag, "mcast MSG_ACCEPT to %d waiting processes [timestamp=%d]", len, *info.local_clock);
diag_msg(info.mstrtid, info.mytid, diag);
}
void handle_request(struct msg incoming_msg, struct state_info info) {
// handle Lamport clocks
char diag[200];
update_lamport_recv(incoming_msg.timestamp, info.local_clock);
int *my_weight_ptr = g_hash_table_lookup(info.skiers_weights, &info.mytid);
int my_weight = *my_weight_ptr;
int *sender_weight_ptr = g_hash_table_lookup(info.skiers_weights, &incoming_msg.sender_tid);
int sender_weight = *sender_weight_ptr;
if (info.phase != PHASE_WAIT_ACCEPTS) {
// Always send ACCEPT, don't care about priorities in those phases
send_accept_msg(incoming_msg.sender_tid, info);
} else {
// Send ACCEPT only if:
// a) my priority is worse than the sender's priority,
// b) or my priority is better but we both can fit
// c) or I want the other lift
if (*info.my_lift_number != incoming_msg.lift_number) { // I want the other lift
send_accept_msg(incoming_msg.sender_tid, info); return;
}
// my priority is worse
else if (*info.my_request_timestamp > incoming_msg.timestamp) {
send_accept_msg(incoming_msg.sender_tid, info); return;
}
else if (*info.my_request_timestamp == incoming_msg.timestamp) {
if (incoming_msg.timestamp % 2 == 0) { // admit the heavier skier
if (my_weight > sender_weight) {
send_accept_msg(incoming_msg.sender_tid, info); return;
}
}
else { // admit the lighter skier
if (my_weight <= sender_weight) {
send_accept_msg(incoming_msg.sender_tid, info); return;
}
}
}
// my priority is better
// ELSE
if (my_weight + sender_weight <= *info.lift_free) {
send_accept_msg(incoming_msg.sender_tid, info);
}
else { // add the sender to the queue of waiting requests for the lift
int *tid = malloc(sizeof(int));
memcpy(tid, &incoming_msg.sender_tid, sizeof(int));
g_queue_push_tail(info.waiting_req_q, tid);
int *pushed = g_queue_peek_tail(info.waiting_req_q);
sprintf(diag, "*** pushed tid=%d", *pushed);
diag_msg(info.mstrtid, info.mytid, diag);
}
}
};
void handle_message(struct msg incoming_msg, struct state_info info) {
char diag[200];
sprintf(diag,"receive %s from %d [phase=%s, timestamp=%d, lift_number=%s]",
stringify(incoming_msg.tag), incoming_msg.sender_tid, stringify(info.phase),
incoming_msg.timestamp, stringify(incoming_msg.tag == MSG_ACCEPT ? -1 : incoming_msg.lift_number));
diag_msg(info.mstrtid, info.mytid, diag);
switch (incoming_msg.tag) {
case MSG_REQUEST: handle_request(incoming_msg, info); break;
case MSG_ACCEPT: handle_accept (incoming_msg, info); break;
case MSG_RELEASE: handle_release(incoming_msg, info); break;
}
}
void handle_accept (struct msg incoming_msg, struct state_info info) {
char diag[200];
update_lamport_recv(incoming_msg.timestamp, info.local_clock);
int *my_weight_ptr = g_hash_table_lookup(info.skiers_weights, &info.mytid);
int my_weight = *my_weight_ptr;
int *sender_weight_ptr = g_hash_table_lookup(info.skiers_weights, &incoming_msg.sender_tid);
int sender_weight = *sender_weight_ptr;
// decrement the pending_accepts_sum by sender weight
*info.pending_accepts_sum -= sender_weight;
*info.accepts_received += 1;
sprintf(diag, "*** my_lift_number=%s", stringify(*info.my_lift_number));
diag_msg(info.mstrtid, info.mytid, diag);
int *lift_free = (*info.my_lift_number == LIFT_1 ? info.lift1_free : info.lift2_free);
sprintf(diag, "free space on lift %d, pending accepts sum %d, accepts received %d, my weight %d",
*lift_free, *info.pending_accepts_sum, *info.accepts_received, my_weight);
diag_msg(info.mstrtid, info.mytid, diag);
if (*lift_free - *info.pending_accepts_sum >= my_weight) {
sprintf(diag, "can enter lift now");
*lift_free -= my_weight;
*info.can_enter_lift = 1;
} else if (g_hash_table_size(info.skiers_weights) - 1 == *info.accepts_received) {
sprintf(diag, "n-1 accepts - can enter lift now");
*lift_free -= my_weight;
*info.can_enter_lift = 1;
} else {
sprintf(diag, "not entering the lift yet");
*info.can_enter_lift = 0;
}
diag_msg(info.mstrtid, info.mytid, diag);
};
void bcast_request_msg(struct state_info info) {
int tag = MSG_REQUEST;
*info.local_clock += 1;
pvm_initsend(PvmDataDefault);
pvm_pkint(&tag, 1, 1);
pvm_pkint(&info.mytid, 1, 1);
pvm_pkint(info.local_clock, 1, 1);
pvm_pkint(info.my_lift_number, 1, 1);
pvm_bcast(GROUP, MSG_REQUEST);
*info.my_request_timestamp = *info.local_clock;
char diag[200];
sprintf(diag, "bcast MSG_REQUEST [timestamp=%d, lift_number=%s]", *info.local_clock, stringify(*info.my_lift_number));
diag_msg(info.mstrtid, info.mytid, diag);
}
void send_accept_msg(int dest_tid, struct state_info info) {
int *sender_weight_ptr = g_hash_table_lookup(info.skiers_weights, &dest_tid);
int old_free = *info.lift_free;
*info.lift_free -= *sender_weight_ptr;
*info.local_clock += 1;
int tag = MSG_ACCEPT;
pvm_initsend(PvmDataDefault);
pvm_pkint(&tag, 1, 1);
pvm_pkint(&info.mytid, 1, 1);
pvm_pkint(info.local_clock, 1, 1);
pvm_send(dest_tid, tag);
char diag[200];
sprintf(diag, "sent MSG_ACCEPT to %d [timestamp=%d], was %d now %d",
dest_tid, *info.local_clock, old_free, *info.lift_free);
diag_msg(info.mstrtid, info.mytid, diag);
}
void bcast_release_msg(struct state_info info) {
int tag = MSG_RELEASE;
*info.local_clock += 1;
pvm_initsend(PvmDataDefault);
pvm_pkint(&tag, 1, 1);
pvm_pkint(&info.mytid, 1, 1);
pvm_pkint(info.local_clock, 1, 1);
pvm_pkint(info.my_lift_number, 1, 1);
pvm_bcast(GROUP, MSG_RELEASE);
// Unallocate space on the lift
int *my_weight_ptr = g_hash_table_lookup(info.skiers_weights, &info.mytid);
int my_weight = *my_weight_ptr;
int *lift_free = (*info.my_lift_number == LIFT_1 ? info.lift1_free : info.lift2_free);
*lift_free += my_weight;
char diag[200];
sprintf(diag, "bcast MSG_RELEASE [timestamp=%d, lift_number=%s]", *info.local_clock, stringify(*info.my_lift_number));
diag_msg(info.mstrtid, info.mytid, diag);
}
static void
hash_table_resize(hash_table * hash_t)
{
hash_node **new_nodes;
hash_node *node;
hash_node *next;
long hash_val;
long new_size;
long i;
if ((hash_t->size >= 3 * hash_t->nnodes && hash_t->size > HASH_TABLE_MIN_SIZE)
|| (3 * hash_t->size <= hash_t->nnodes && hash_t->size < HASH_TABLE_MAX_SIZE))
{
new_size = get_closest(hash_t->nnodes);
new_nodes = (hash_node **) diag_malloc(sizeof(hash_node *) * new_size);
if (new_nodes == NULL)
{
diag_msg("Unable to allocate memory\n");
return;
}
memset(new_nodes, 0, sizeof(hash_node *) * new_size);
for (i = 0; i < hash_t->size; i++)
for (node = hash_t->nodes[i]; node; node = next)
{
next = node->next;
hash_val = (*hash_t->hash_func) (node->key, new_size);
node->next = new_nodes[hash_val];
new_nodes[hash_val] = node;
}
diag_free(hash_t->nodes);
hash_t->nodes = new_nodes;
hash_t->size = new_size;
}
}
main()
{
GHashTable* skiers_weights = g_hash_table_new(g_str_hash, g_str_equal);
GQueue *waiting_req_q1 = g_queue_new();
GQueue *waiting_req_q2 = g_queue_new();
int first_lift_free, second_lift_free;
int mytid, mstrtid, myind, number_of_skiers, *tids, first_lift_capacity,
second_lift_capacity, i, phase, local_clock;
time_t t;
char slave_name[NAMESIZE];
char diag[200];
struct state_info info;
mytid = pvm_mytid();
srand(time(NULL) + mytid);
gethostname(slave_name, NAMESIZE);
pvm_joingroup(GROUP);
get_initial_values(&mstrtid, &number_of_skiers, &tids, &skiers_weights, &first_lift_capacity, &second_lift_capacity);
info.mstrtid = mstrtid;
first_lift_free = first_lift_capacity;
second_lift_free = second_lift_capacity;
int *my_weight_ptr = g_hash_table_lookup(skiers_weights, &mytid);
int my_weight = *my_weight_ptr;
int all_skiers_weight = 0;
for(i=0; i<number_of_skiers; i++) {
int *lookup = g_hash_table_lookup(skiers_weights, &tids[i]);
all_skiers_weight += *lookup;
}
all_skiers_weight -= my_weight;
sprintf(diag, "sum of all other skiers' weights = %d", all_skiers_weight);
diag_msg(mstrtid, mytid, diag);
i=0;
while (tids[i] != mytid) {
i++;
}
pvm_initsend(PvmDataDefault);
pvm_pkint(&mytid, 1, 1);
pvm_pkstr(slave_name);
int *wat_to_send = g_hash_table_lookup(skiers_weights, &mytid);
pvm_pkint(wat_to_send, 1, 1);
pvm_send(mstrtid, MSG_SLV);
// bariera
local_clock = 0;
pvm_barrier(GROUP, number_of_skiers);
int time_to_wait;
// main loop
diag_msg(mstrtid, mytid, "entering main loop");
while (1) {
int can_enter_lift = 0;
int chosen_lift = -1;
int accepts_received = 0;
int my_request_timestamp = -1;
info.accepts_received = &accepts_received;
info.my_request_timestamp = &my_request_timestamp;
phase = PHASE_DOWNHILL;
struct timeval timeout;
random_timeout(&timeout, 3, 10);
struct timeval start_time;
gettimeofday(&start_time, NULL);
struct timeval elapsed;
elapsed.tv_sec = 0;
elapsed.tv_usec = 0;
sprintf(diag, "entered %s, time=%zu.%zu", stringify(phase), timeout.tv_sec, timeout.tv_usec);
diag_msg(mstrtid, mytid, diag);
while (1) {
int bufid = pvm_trecv(-1, -1, &timeout);
if (bufid) {
// diag_msg(mstrtid, mytid, "Got message in PHASE_DOWNHILL");
struct msg incoming_msg;
unpack(&incoming_msg);
int *sender_weight = g_hash_table_lookup(skiers_weights, &incoming_msg.sender_tid);
// handle the message accordingly
prepare_info(&info, mytid, &local_clock, phase, &chosen_lift, &can_enter_lift,
&first_lift_free, &second_lift_free, incoming_msg,
waiting_req_q1, waiting_req_q2);
info.skiers_weights = skiers_weights;
handle_message(incoming_msg, info);
}
// break the loop if time elapsed is more than the timeout, else wait for another message
struct timeval current_time;
gettimeofday(¤t_time, NULL);
timeval_subtract(&elapsed, ¤t_time, &start_time);
if (elapsed.tv_sec * 1000000 + elapsed.tv_usec >= timeout.tv_sec * 1000000 + timeout.tv_usec)
break;
else
timeval_subtract(&timeout, &timeout, &elapsed);
}
// want to go up
diag_msg(mstrtid, mytid, "");
phase = PHASE_WAIT_REQUEST;
// choose the lift (1 or 2)
// determine if we can fit on the lift (based on our knowledge from the accepts we had sent)
sprintf(diag, "entered PHASE_WAIT_REQUEST, weight=%d, LIFT_1=%d, LIFT_2=%d",my_weight,first_lift_free,second_lift_free);
diag_msg(mstrtid, mytid, diag);
if (my_weight > first_lift_free && my_weight > second_lift_free) {
// no lift for us
// wait for RELEASE messages until we can fit in the lift
// meanwhile: handle all incoming messages, responding accordingly (ALWAYS respond with accepts)
while (1) {
sprintf(diag, "no space in lifts, weight=%d, LIFT_1=%d, LIFT_2=%d",my_weight,first_lift_free,second_lift_free);
diag_msg(mstrtid, mytid, diag);
int bufid = pvm_recv(-1, -1);
struct msg incoming_msg;
unpack(&incoming_msg);
prepare_info(&info, mytid, &local_clock, phase, &chosen_lift, &can_enter_lift,
&first_lift_free, &second_lift_free, incoming_msg,
waiting_req_q1, waiting_req_q2);
info.skiers_weights = skiers_weights;
handle_message(incoming_msg, info);
// now check if we should break the loop and go to the next phase!
if (chosen_lift == LIFT_1 || chosen_lift == LIFT_2) {
sprintf(diag, "weight=%d, LIFT_1=%d, LIFT_2=%d, choosing %s",
my_weight, first_lift_free, second_lift_free, stringify(chosen_lift));
diag_msg(mstrtid, mytid, diag);
// broadcast a request with our chosen lift and go to (*)
bcast_request_msg(info);
break;
}
}
}
else { // if there is a fitting lift
if (my_weight <= first_lift_free && my_weight > second_lift_free) { // can only go to first lift
chosen_lift = LIFT_1;
}
else if (my_weight > first_lift_free && my_weight <= second_lift_free) { // can only go to second lift
chosen_lift = LIFT_2;
}
else { // can go to either lift - worst fit
if (first_lift_free > second_lift_free)
chosen_lift = LIFT_1;
else if (first_lift_free < second_lift_free)
chosen_lift = LIFT_2;
else // equal
chosen_lift = (rand() % 2 == 1) ? LIFT_1 : LIFT_2;
}
info.my_lift_number = &chosen_lift;
info.mytid = mytid;
info.local_clock = &local_clock;
info.skiers_weights = skiers_weights;
// broadcast a request with our chosen lift and go to (*)
bcast_request_msg(info);
// sprintf(diag,"So I am here just before broadcasting REQUEST and I choose lift %d and in info %d",chosen_lift, *info.my_lift_number);
sprintf(diag, "weight=%d, LIFT_1=%d, LIFT_2=%d, choosing %s",
my_weight, first_lift_free, second_lift_free, stringify(chosen_lift));
diag_msg(mstrtid, mytid, diag);
}
sprintf(diag, "*** chosen_lift=%s", stringify(chosen_lift));
// waiting for accepts (*)
// wait for enough accepts or just as much as required to be sure that we can get in
// meanwhile: handle all incoming messages, responding accordingly (not send back accept only to those with worse priority that can't fit together with us)
// diag_msg(mstrtid, mytid, "entering PHASE_WAIT_ACCEPTS");
phase = PHASE_WAIT_ACCEPTS;
int pending = all_skiers_weight;
info.pending_accepts_sum = &pending;
sprintf(diag, "entered PHASE_WAIT_ACCEPTS, lift=%s", stringify(chosen_lift));
diag_msg(mstrtid, mytid, diag);
while (1) {
int bufid = pvm_recv(-1, -1);
struct msg incoming_msg;
unpack(&incoming_msg);
prepare_info(&info, mytid, &local_clock, phase, &chosen_lift, &can_enter_lift,
&first_lift_free, &second_lift_free, incoming_msg,
waiting_req_q1, waiting_req_q2);
handle_message(incoming_msg, info);
// check if there are enough amount of acceptes - can break the loop and go to the critical section
if (can_enter_lift) {
break;
}
}
// random waiting up to the hill - critical section
phase = PHASE_CRITICAL;
random_timeout(&timeout, 3, 10);
gettimeofday(&start_time, NULL);
elapsed.tv_sec = 0;
elapsed.tv_usec = 0;
sprintf(diag, "entered PHASE_CRITICAL, lift=%s, time=%zu.%zu",
stringify(chosen_lift), timeout.tv_sec, timeout.tv_usec);
diag_msg(mstrtid, mytid, diag);
while (1) {
int bufid = pvm_trecv(-1, -1, &timeout);
if (bufid) {
// unpack the received message
struct msg incoming_msg;
// int msgtag = -1, sender_tid = -1, lift_number = -1, timestamp = -1;
unpack(&incoming_msg);
// handle the message accordingly
prepare_info(&info, mytid, &local_clock, phase, &chosen_lift, &can_enter_lift,
&first_lift_free, &second_lift_free, incoming_msg,
waiting_req_q1, waiting_req_q2);
handle_message(incoming_msg, info);
}
// break the loop if time elapsed is more than the timeout, else wait for another message
struct timeval current_time;
gettimeofday(¤t_time, NULL);
timeval_subtract(&elapsed, ¤t_time, &start_time);
if (elapsed.tv_sec * 1000000 + elapsed.tv_usec >= timeout.tv_sec * 1000000 + timeout.tv_usec)
break;
else
timeval_subtract(&timeout, &timeout, &elapsed);
}
// release - broadcast the RELEASE message to all others
info.mytid = mytid;
info.local_clock = &local_clock;
info.my_lift_number = &chosen_lift;
bcast_release_msg(info);
// send all the requests stored in the queue (mcast automatically clears it)
mcast_accept_msg(info);
}
pvm_exit();
}