void *k_receive_message_nonblocking(int* pid){
Node* res;
void* msg;
if (!is_pid_valid(*pid)|| isEmpty(get_message_queue(*pid))){
return NULL;
}
res = dequeue_message_queue(*pid);
msg = res->data;
k_release_node(res);
return msg;
}
Node* k_receive_message_node(int* sender_id) {
Node* res;
__disable_irq();
while (isEmpty(get_message_queue(gp_current_process->m_pid))){
__enable_irq();
block_current_process_on_receive();
__disable_irq();
}
res = dequeue_message_queue(gp_current_process->m_pid);
__enable_irq();
if (res != NULL) {
*sender_id = res->sender_id;
}
return res;
}
void *k_receive_message(int* p_pid){
Node* res;
void* msg;
__disable_irq();
while (isEmpty(get_message_queue(gp_current_process->m_pid))){
__enable_irq();
block_current_process_on_receive();
__disable_irq();
}
res = dequeue_message_queue(gp_current_process->m_pid);
__enable_irq();
if (res == NULL) {
return NULL;
}
*p_pid = res->sender_id;
msg = res->data;
k_release_node(res);
return msg;
}
/**
* obtains the resources needed by the session for it to function.
*
* @function initialize
*
* @date 2015-02-12
*
* @revision none
*
* @designer EricTsang
*
* @programmer EricTsang
*
* @note none
*
* @signature static void initialize(int clntPid, int priority, char* filePath)
*
* @param clntPid process id of the session's client process
*/
static void initialize(int clntPid, int priority, char* filePath)
{
Message pidMsg; /* used to send client the PID of this process */
char fatalstring[MAX_STR_LEN]; /* buffer used to print fatal messages */
pidMsg.dataType = MSG_DATA_PID;
/* initialize global client PID */
clientPid = clntPid;
/* set signal handler */
signal(SIGUSR1, sigusr1_handler);
/* get the message queue. */
get_message_queue(&msgQId);
/* verify priority input */
if(priority < MIN_PROC_PRIO || priority > MAX_PROC_PRIO)
{
sprintf(fatalstring, "invalid priority; %d <= priority <= %d\n",
MIN_PROC_PRIO, MAX_PROC_PRIO);
fatal(fatalstring);
}
/* open the file */
fd = open(filePath, 0);
if(fd == -1)
{
sprintf(fatalstring, "failed to open file: %d\n", errno);
fatal(fatalstring);
}
/* send the client the session's PID */
pidMsg.data.pidMsg.pid = getpid();
msg_send(msgQId, &pidMsg, clientPid);
}
