diff --git a/client.c b/client.c index 3ec05cf..d2b6780 100644 --- a/client.c +++ b/client.c @@ -1,5 +1,6 @@ #include #include +#include #include #include #include @@ -9,8 +10,7 @@ #include "commands.h" // Make a macro for this cause I'm not typing sizeof twice every time -#define send(queue_id, msgbuf_ptr) \ - msgsnd(queue_id, msgbuf_ptr, sizeof(*(msgbuf_ptr)) - sizeof(long), 0) +#define send(queue_id, msgbuf_ptr) msgsnd(queue_id, msgbuf_ptr, sizeof(*(msgbuf_ptr)) - sizeof(long), 0) static void heartbeat_loop(int server_queue_id, const char *client_id) { msgbuf_t msg = {.mtype = Hearbeat, .sender = ""}; @@ -33,8 +33,7 @@ static void cleanup_queue(int qid) { static void input_loop(int server_queue_id, const char *client_id) { while (1) { // Minimum length plus extra space fore command name and seperators - // I'd prefer some more space than required to not have to worry about cut - // offs + // I'd prefer some more space than required to not have to worry about cutoffs char buffer[COMMAND_LENGTH + MESSAGE_LENGTH + 64]; if (fgets(buffer, sizeof(buffer), stdin) == NULL) { break; @@ -43,41 +42,32 @@ static void input_loop(int server_queue_id, const char *client_id) { buffer[strcspn(buffer, "\n")] = '\0'; if (strncmp(buffer, "/msg ", 5) == 0) { - // In a /msg command we expect {u|g}: char *space_ptr = strchr(buffer + 5, ' '); if (space_ptr == NULL) { - printf("Invalid /msg format. Use /msg u: \n"); + printf("Invalid /msg format. Use /msg or # \n"); continue; } + char target[COMMAND_LENGTH]; size_t target_len = space_ptr - (buffer + 5); - if (target_len >= COMMAND_LENGTH) { - printf("Target nickname too long\n"); + + if (target_len == 0 || target_len >= COMMAND_LENGTH) { + printf("Invalid target length\n"); continue; } - strncpy(target, buffer + 5, target_len); + + strncpy(target, buffer + 5, target_len); // Copy everything including '#' if present target[target_len] = '\0'; + char *message = space_ptr + 1; if (strlen(message) == 0) { printf("Message cannot be empty\n"); continue; } - // Check the format of the command string - if (target[1] != ':') { - printf("Invalid target format. Use u: or g:\n"); - continue; - } - - if (target[0] != 'u' && target[0] != 'g') { - printf("Invalid target type. Use 'u' for user or 'g' for group\n"); - continue; - } - msgbuf_t msg = {.mtype = Message, .sender = ""}; strncpy(msg.sender, client_id, COMMAND_LENGTH - 1); - snprintf(msg.command, COMMAND_LENGTH, "%s", target); + strncpy(msg.command, target, COMMAND_LENGTH - 1); // Send as-is (with '#' if group) strncpy(msg.message, message, MESSAGE_LENGTH - 1); if (send(server_queue_id, &msg) == -1) { perror("msgsnd(/msg) failed"); @@ -85,12 +75,12 @@ static void input_loop(int server_queue_id, const char *client_id) { } else if (strncmp(buffer, "/list ", 6) == 0) { char *offset = buffer + 6; - if (strcmp(offset, "active") != 0 && strcmp(offset, "all") != 0) { - printf("Invalid list type. Use /list active or /list all\n"); + if (strcmp(offset, "active") != 0 && strcmp(offset, "all") != 0 && strcmp(offset, "groups") != 0) { + printf("Invalid list type. Use /list active or /list all or /list groups\n"); continue; } - msgbuf_t msg = {.mtype = List_clients, .sender = ""}; + msgbuf_t msg = {.mtype = List, .sender = ""}; strncpy(msg.sender, client_id, COMMAND_LENGTH - 1); strncpy(msg.command, offset, COMMAND_LENGTH - 1); if (send(server_queue_id, &msg) == -1) { @@ -154,16 +144,19 @@ int main(int argc, char *argv[]) { /* Wait for login response (server replies with mtype = Login) */ msgbuf_t resp; - ssize_t r = - msgrcv(client_queue_id, &resp, sizeof(resp) - sizeof(long), Login, 0); + ssize_t r = msgrcv(client_queue_id, &resp, sizeof(resp) - sizeof(long), Login, 0); if (r == -1) { perror("msgrcv(login response) failed"); cleanup_queue(client_queue_id); return 1; } - if (resp.stype != ACK_ACCEPTED) { - fprintf(stderr, "Login rejected: code=%d\n", resp.stype); + if (resp.stype == ERR_ALREADY_LOGGED_IN) { + fprintf(stderr, "Login failed: User already logged in\n"); + cleanup_queue(client_queue_id); + return 1; + } else if (resp.stype == ERR_USER_NOT_FOUND) { + fprintf(stderr, "Login failed: User not found\n"); cleanup_queue(client_queue_id); return 1; } @@ -182,8 +175,7 @@ int main(int argc, char *argv[]) { while (1) { msgbuf_t incoming; - ssize_t got = msgrcv(client_queue_id, &incoming, - sizeof(incoming) - sizeof(long), 0, 0); + ssize_t got = msgrcv(client_queue_id, &incoming, sizeof(incoming) - sizeof(long), 0, 0); if (got == -1) { perror("msgrcv(incoming) failed"); @@ -198,10 +190,12 @@ int main(int argc, char *argv[]) { case Message: printf("%s: %s\n", incoming.sender, incoming.message); break; - case List_clients: { + case List: { // Check the command field for the list type if (strncmp(incoming.command, "active", COMMAND_LENGTH) == 0) { printf("Active clients:\n%s\n", incoming.message); + } else if (strncmp(incoming.command, "group", COMMAND_LENGTH) == 0) { + printf("All group members:\n%s\n", incoming.message); } else { printf("All clients:\n%s\n", incoming.message); } @@ -209,9 +203,15 @@ int main(int argc, char *argv[]) { } case Inbox: { // Upon recieving an inbox message, check the command field for the index + // Index of -1 means that there are no messages in the mailbox + if (strcmp(incoming.command, "-1") == 0) { + printf("Your inbox is empty.\n"); + break; + } + // Index of 0 means that there are messages in the mailbox if (strcmp(incoming.command, "0") == 0) { - printf("You have messages in your mailbox!\n"); + printf("You have messages in your box!\n"); continue; } @@ -219,8 +219,7 @@ int main(int argc, char *argv[]) { if (strcmp(incoming.command, "1") == 0) { printf("Your inbox messages:\n"); } - printf("[%s] %s: %s\n", incoming.command, incoming.sender, - incoming.message); + printf("[%s] %s: %s\n", incoming.command, incoming.sender, incoming.message); break; } case Signal: @@ -228,19 +227,16 @@ int main(int argc, char *argv[]) { if (incoming.stype == ACK_ACCEPTED) { printf("Message sent successfully.\n"); } else if (incoming.stype == ACK_DELIVERED) { - printf("Message delivered to the %s.\n", incoming.command); + printf("Message delivered to %s.\n", incoming.sender); } else if (incoming.stype == ERR_USER_NOT_FOUND) { printf("Your message could not be delivered: User not found.\n"); } else { // Display whatever if I forgot to handle something - printf("Your message could not be delivered: Error code %d.\n", - incoming.stype); + printf("Unhandled signal - code %d.\n", incoming.stype); } - break; default: - printf("Received unknown command of mtype=%ld stype=%d\n", - (long)incoming.mtype, incoming.stype); + printf("Received unknown command of mtype=%ld stype=%d\n", (long)incoming.mtype, incoming.stype); break; } } diff --git a/commands.h b/commands.h index 33e61b0..180faef 100644 --- a/commands.h +++ b/commands.h @@ -9,28 +9,30 @@ typedef enum { Login, Logout, Hearbeat, - List_clients, + List, + Group, Mute, Unmute, Signal, Inbox -} CommandType; +} Command_t; typedef enum { - ACK_ACCEPTED = 0, - ACK_DELIVERED, - ERR_UNKNOWN_COMMAND, - ERR_NOT_LOGGED_IN, - ERR_ALREADY_LOGGED_IN, - ERR_USER_NOT_FOUND, - ERR_USER_MUTED, - ERR_INVALID_FORMAT + ACK_ACCEPTED = 0, + ACK_DELIVERED, + ERR_UNKNOWN_COMMAND, + ERR_NOT_LOGGED_IN, + ERR_ALREADY_LOGGED_IN, + ERR_USER_NOT_FOUND, + ERR_USER_MUTED, + ERR_INVALID_FORMAT } Signal_t; typedef struct { - CommandType mtype; - Signal_t stype; // Used with mtype = signal. Responses from the server - to specify errors or acks - char sender[COMMAND_LENGTH]; // Who sent the message + Command_t mtype; + Signal_t stype; // Used with mtype = signal. Responses from the server - to + // specify errors or acks + char sender[COMMAND_LENGTH]; // Who sent the message char command[COMMAND_LENGTH]; // Functions as an attribute to mtype - // nicknames, id to send/mute to char message[MESSAGE_LENGTH]; // Actual message content diff --git a/server.c b/server.c index 6a2e630..cccbc67 100644 --- a/server.c +++ b/server.c @@ -15,36 +15,35 @@ #include "commands.h" #include "util/util.h" -#define send(queue_id, msgbuf_ptr) \ - msgsnd(queue_id, msgbuf_ptr, sizeof(*(msgbuf_ptr)) - sizeof(long), 0) +#define send(queue_id, msgbuf_ptr) msgsnd(queue_id, msgbuf_ptr, sizeof(*(msgbuf_ptr)) - sizeof(long), 0) typedef struct { char sender[COMMAND_LENGTH]; char command[COMMAND_LENGTH]; char message[MESSAGE_LENGTH]; - int message_id; + char message_id[COMMAND_LENGTH]; } saved_message_t; typedef struct { - char *id; + char id[COMMAND_LENGTH]; bool logged_in; char *muted_clients; - char nickname[16]; + char nickname[COMMAND_LENGTH]; // Nicknames cannot contain special characters + // like # (reserved for groups) int queue_id; long last_seen; // Things for keeping track of the saved messages saved_message_t saved_messages[20]; int saved_message_count; -} Client; +} Client_t; typedef struct { - Client **clients; - char name[16]; + Client_t **members; + char name[COMMAND_LENGTH - 1]; // In the command one char is used for # to indicate a group int client_count; -} Group; +} Group_t; -static void handle_hearbeat_timeouts(Client *clients, int client_count, - int semaphore_id) { +static void handle_hearbeat_timeouts(Client_t *clients, int client_count, int semaphore_id) { struct sembuf sem_op = { .sem_num = 0, .sem_op = -1, @@ -56,10 +55,8 @@ static void handle_hearbeat_timeouts(Client *clients, int client_count, struct timeval tv; gettimeofday(&tv, NULL); for (int i = 0; i < client_count; i++) { - if (clients[i].logged_in && - (tv.tv_sec - clients[i].last_seen) > HEARTBEAT_TIMEOUT) { - printf("Client %s has timed out due to missed heartbeats\n", - clients[i].id); + if (clients[i].logged_in && (tv.tv_sec - clients[i].last_seen) > HEARTBEAT_TIMEOUT) { + printf("Client %s has timed out due to missed heartbeats\n", clients[i].id); clients[i].logged_in = false; clients[i].queue_id = -1; } @@ -74,24 +71,29 @@ int main(int argc, char **argv) { // TODO: Load config file with clients and groups int client_count = 2; int group_count = 3; - int clients_memory_id = - shmget(IPC_PRIVATE, sizeof(Client) * client_count, IPC_CREAT | 0666); - Client *clients = shmat(clients_memory_id, NULL, 0); - Group *groups = malloc(sizeof(Group) * 3); + int clients_memory_id = shmget(IPC_PRIVATE, sizeof(Client_t) * client_count, IPC_CREAT | 0666); + Client_t *clients = shmat(clients_memory_id, NULL, 0); + Group_t *groups = malloc(sizeof(Group_t) * 3); int semaphore_id = semget(IPC_PRIVATE, 1, IPC_CREAT | 0666); semctl(semaphore_id, 0, SETVAL, 1); - clients[0] = (Client){.id = "test1", - .logged_in = false, - .muted_clients = NULL, - .nickname = "Kregielnia", - .last_seen = 0}; - clients[1] = (Client){.id = "test2", - .logged_in = false, - .muted_clients = NULL, - .nickname = "Bajzel", - .last_seen = 0}; + clients[0] = + (Client_t){.id = "test1", .logged_in = false, .muted_clients = NULL, .nickname = "Kregielnia", .last_seen = 0}; + clients[1] = + (Client_t){.id = "test2", .logged_in = false, .muted_clients = NULL, .nickname = "Bajzel", .last_seen = 0}; + + groups[0] = (Group_t){.name = "HelloChat", .client_count = 2, .members = NULL}; + groups[0].members = malloc(sizeof(Client_t *) * client_count); + groups[0].members[0] = &clients[0]; + groups[0].members[1] = &clients[1]; + + groups[1] = (Group_t){.name = "Macarena", .client_count = 0, .members = NULL}; + groups[1].members = malloc(sizeof(Client_t *) * client_count); + + groups[2] = (Group_t){.name = "Bananownia", .client_count = 1, .members = NULL}; + groups[2].members = malloc(sizeof(Client_t *) * client_count); + groups[2].members[0] = &clients[1]; int server_queue_id = msgget(IPC_PRIVATE, 0666 | IPC_CREAT); @@ -100,8 +102,7 @@ int main(int argc, char **argv) { return 1; } - int id_file_handle = - open("/home/piotr/server_queue_id", O_WRONLY | O_CREAT | O_TRUNC, 0666); + int id_file_handle = open("/home/piotr/server_queue_id", O_WRONLY | O_CREAT | O_TRUNC, 0666); if (!id_file_handle) { perror("Failed to open file"); return 1; @@ -121,13 +122,12 @@ int main(int argc, char **argv) { msgbuf_t msgbuf; while (1) { // Read from the ipc, then handle the command - int read_status = - msgrcv(server_queue_id, &msgbuf, sizeof(msgbuf) - sizeof(long), 0, 0); + int read_status = msgrcv(server_queue_id, &msgbuf, sizeof(msgbuf) - sizeof(long), 0, 0); switch (msgbuf.mtype) { case Login: { printf("Received login request for id: %s\n", msgbuf.sender); - Client *client = NULL; + Client_t *client = NULL; for (int i = 0; i < client_count; i++) { if (strncmp(clients[i].id, msgbuf.sender, COMMAND_LENGTH) == 0) { client = &clients[i]; @@ -185,7 +185,7 @@ int main(int argc, char **argv) { case Message: { // Find the client that sent the message then forward it to all the // specified recipients - Client *client = NULL; + Client_t *client = NULL; for (int i = 0; i < client_count; i++) { if (strncmp(clients[i].id, msgbuf.sender, COMMAND_LENGTH) == 0) { client = &clients[i]; @@ -193,8 +193,7 @@ int main(int argc, char **argv) { } } - printf("Received message from client id %s to %s\n", msgbuf.sender, - msgbuf.command); + printf("Received message from client id %s to %s\n", msgbuf.sender, msgbuf.command); if (client == NULL || !client->logged_in) { // Client not found or not logged in @@ -208,24 +207,30 @@ int main(int argc, char **argv) { } // Now we have to decode if we are to forward this message to a user or a - // group first character of command indicates that - u or g + // group. A group is indicated by a # at the start of the command char target_type = msgbuf.command[0]; - char target_id[COMMAND_LENGTH]; - // Skip the first char and a separtor (:) - strncpy(target_id, msgbuf.command + 2, COMMAND_LENGTH - 2); + Client_t **recipients = malloc(sizeof(Client_t *) * client_count - 1); // We won't send to ourselves so one less - if (target_type == 'u') { - Client *target_client = NULL; + if (target_type != '#') { for (int i = 0; i < client_count; i++) { - if (strncmp(clients[i].nickname, target_id, COMMAND_LENGTH) == 0) { - target_client = &clients[i]; + if (strncmp(clients[i].nickname, msgbuf.command, COMMAND_LENGTH) == 0) { + recipients[0] = &clients[i]; + break; + } + } + } else { + // Target is a group, find it first + Group_t *target_group = NULL; + for (int i = 0; i < group_count; i++) { + if (strncmp(groups[i].name, msgbuf.command + 1, COMMAND_LENGTH - 1) == 0) { + target_group = &groups[i]; break; } } - if (target_client == NULL) { - // Target client not found or not logged in - printf("Target client %s not found\n", target_id); + // Target group not found + if (target_group == NULL) { + printf("Target group %s not found\n", msgbuf.command + 1); msgbuf_t response = { .mtype = Message, .stype = ERR_USER_NOT_FOUND, @@ -234,50 +239,55 @@ int main(int argc, char **argv) { continue; } + // Forward the message to all group members except the sender + int recipient_idx = 0; + for (int i = 0; i < target_group->client_count; i++) { + if (strncmp(target_group->members[i]->id, client->id, COMMAND_LENGTH) == 0) { + continue; + } + recipients[recipient_idx++] = target_group->members[i]; + } + + if (recipient_idx < client_count - 1) { + recipients[recipient_idx] = NULL; + } + } + + // Now forward the message to all recipients + for (int i = 0; i < client_count - 1; i++) { + Client_t *target_client = recipients[i]; + // Just the empty pointer so no more recipients + if (target_client == NULL) + break; + // Check if the target is online or not, if they are not, store the // message if (!target_client->logged_in) { + saved_message_t *saved_msg = NULL; if (target_client->saved_message_count >= 20) { // Discard the oldest one and shift the rest to make room for (int i = 1; i < target_client->saved_message_count; i++) { - target_client->saved_messages[i - 1] = - target_client->saved_messages[i]; + target_client->saved_messages[i - 1] = target_client->saved_messages[i]; } - saved_message_t *saved_msg = - &target_client - ->saved_messages[target_client->saved_message_count - 1]; - strncpy(saved_msg->sender, client->nickname, COMMAND_LENGTH); - strncpy(saved_msg->message, msgbuf.message, MESSAGE_LENGTH); - saved_msg->message_id = rand(); // Random id for the message - printf("Message saved for offline client %s\n", target_id); - - // Send out an ack for the sender - msgbuf_t response = { - .mtype = Message, - .stype = ACK_ACCEPTED, - }; - send(client->queue_id, &response); - continue; + saved_msg = &target_client->saved_messages[target_client->saved_message_count - 1]; + } else { + // There is room for a new message + saved_msg = &target_client->saved_messages[target_client->saved_message_count++]; } - saved_message_t *saved_msg = - &target_client - ->saved_messages[target_client->saved_message_count++]; + get_id(saved_msg->message_id); strncpy(saved_msg->sender, client->nickname, COMMAND_LENGTH); strncpy(saved_msg->message, msgbuf.message, MESSAGE_LENGTH); - saved_msg->message_id = rand(); // Random id for the message - msgbuf_t response = { .mtype = Message, .stype = ACK_ACCEPTED, }; send(client->queue_id, &response); - printf("Message saved for offline client %s\n", target_id); + printf("Message saved for offline client %s\n", target_client->id); continue; } - printf("Forwarding message from user %s to %s\n", client->nickname, - target_client->nickname); + printf("Forwarding message from user %s to %s\n", client->nickname, target_client->nickname); msgbuf_t forward_msg = { .mtype = Message, .sender = "", @@ -291,27 +301,14 @@ int main(int argc, char **argv) { send(client->queue_id, &forward_msg); printf("Forwarding message: %s\n", msgbuf.message); - } else if (target_type == 'g') { - // Forward to a group - - } else { - printf("Invalid target type: %c\n", target_type); - msgbuf_t response = { - .mtype = Message, - .stype = ERR_INVALID_FORMAT, - }; - send(client->queue_id, &response); - continue; } - // TODO: Accepted and Delivered ack break; } case Logout: { } case Hearbeat: for (int i = 0; i < client_count; i++) { - if (strncmp(clients[i].id, msgbuf.sender, COMMAND_LENGTH) == 0 && - clients[i].logged_in) { + if (strncmp(clients[i].id, msgbuf.sender, COMMAND_LENGTH) == 0 && clients[i].logged_in) { // Take the semaphore to update last_seen struct sembuf sem_op = { .sem_num = 0, @@ -329,8 +326,8 @@ int main(int argc, char **argv) { } } break; - case List_clients: { - Client *client = NULL; + case List: { + Client_t *client = NULL; for (int i = 0; i < client_count; i++) { if (strncmp(clients[i].id, msgbuf.sender, COMMAND_LENGTH) == 0) { client = &clients[i]; @@ -342,6 +339,33 @@ int main(int argc, char **argv) { continue; } + char list_buffer[MESSAGE_LENGTH] = ""; + + if (strncmp(msgbuf.command, "groups", COMMAND_LENGTH) == 0) { + for (int i = 0; i < group_count; i++) { + bool isMember = false; + for (int j = 0; j < groups[i].client_count; j++) { + if (strncmp(groups[i].members[j]->id, client->id, COMMAND_LENGTH) == 0) { + isMember = true; + break; + } + } + + char line[COMMAND_LENGTH + 4 + 9]; + // Tell the user if they are in the group or not + snprintf(line, COMMAND_LENGTH + 4 + 9, "- %s%s\n", groups[i].name, isMember ? " (member)" : ""); + strncat(list_buffer, line, MESSAGE_LENGTH - strlen(list_buffer) - 1); + } + + msgbuf_t response = { + .mtype = List, + .command = "groups", + }; + strncpy(response.message, list_buffer, MESSAGE_LENGTH); + send(client->queue_id, &response); + continue; + } + // Parse the command parameter // Just check if the user wants the active clients // Not worth checking if the other option is valid @@ -349,7 +373,6 @@ int main(int argc, char **argv) { if (strncmp(msgbuf.command, "active", COMMAND_LENGTH) == 0) { active_only = true; } - char list_buffer[MESSAGE_LENGTH] = ""; for (int i = 0; i < client_count; i++) { if (active_only && !clients[i].logged_in) @@ -362,7 +385,7 @@ int main(int argc, char **argv) { } msgbuf_t response = { - .mtype = List_clients, + .mtype = List, .command = "", }; @@ -372,7 +395,7 @@ int main(int argc, char **argv) { break; } case Inbox: { - Client *client = NULL; + Client_t *client = NULL; for (int i = 0; i < client_count; i++) { if (strncmp(clients[i].id, msgbuf.sender, COMMAND_LENGTH) == 0) { client = &clients[i]; @@ -394,20 +417,17 @@ int main(int argc, char **argv) { // the counter in command for (int i = 0; i < client->saved_message_count; i++) { snprintf(response.command, COMMAND_LENGTH, "%d", i + 1); - strncpy(response.sender, client->saved_messages[i].sender, - COMMAND_LENGTH); - strncpy(response.message, client->saved_messages[i].message, - MESSAGE_LENGTH); + strncpy(response.sender, client->saved_messages[i].sender, COMMAND_LENGTH); + strncpy(response.message, client->saved_messages[i].message, MESSAGE_LENGTH); send(client->queue_id, &response); } // Now send ACK_DELIVERED to senders for (int i = 0; i < client->saved_message_count; i++) { saved_message_t *saved_msg = &client->saved_messages[i]; - Client *original_sender = NULL; + Client_t *original_sender = NULL; for (int j = 0; j < client_count; j++) { - if (strncmp(clients[j].nickname, saved_msg->sender, COMMAND_LENGTH) == - 0) { + if (strncmp(clients[j].nickname, saved_msg->sender, COMMAND_LENGTH) == 0) { original_sender = &clients[j]; break; } diff --git a/util/util.c b/util/util.c index ce71823..b21a93e 100644 --- a/util/util.c +++ b/util/util.c @@ -1,15 +1,13 @@ #include #include -static char alphs[] = {'-', '_', '0', '1', '2', '3', '4', '5', '6', '7', '8', - '9', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', - 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', - 'v', 'w', 'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', - 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', - 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', '\0'}; +static char alphs[] = {'-', '_', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', + 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', + 'w', 'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', + 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', '\0'}; -// Generate an id used for messages. Could be less than 16 chars, but thats what -// fits into the `command` field of `msgbuf_t`. +// Generate an id used for messages. +// Could be less than 16 chars, but thats what fits into the `command` field of `msgbuf_t`. void get_id(char *id_buf) { int alph_size = strlen(alphs) - 1;