Using only one message queue.

[wsti_so.git] / src / process2.c

diff --git a/src/process2.c b/src/process2.c
index 2417fe88638fd27bdc543a5d764bca6847540b87..861919ce8b45b606fc11579ace0f6de0de3030e3 100644 (file)
--- a/src/process2.c
+++ b/src/process2.c
@@ -1,6 +1,8 @@
 #include <stdio.h>
 /* exit.. */
 #include <stdlib.h>
+/* strsignal... */
+#include <string.h>
 
 /* open/read/write/close */
 #include <fcntl.h>
@@ -49,6 +51,34 @@ struct message {
 
 struct message * processes = NULL;
 
+/**
+ * Message queue variables
+ */
+key_t qkey = 12356;
+int qid;
+
+struct queue_message {
+       long mtype;
+       int signo[1];
+};
+
+void notify_other_processes(int signo) {
+       int i = 0;
+       struct queue_message msg;
+       msg.signo[0] = signo;
+
+       for (; i < 3; i++) {
+               pid_t pid = processes->pids[i];
+               // Bleh
+               if (i != 1 && pid != 0) {
+                       msg.mtype = i+1;
+                       fprintf(stderr, "[%s] Sending message of type (%d) with value %d\n", "process1", msg.mtype, msg.signo[0]);
+                       msgsnd(qid, &msg, sizeof(msg), 0);
+                       fprintf(stderr, "[%s] Sending signal %s (%d) to PID: %d\n", "process2", strsignal(SIGUSR1), SIGUSR1, pid);
+                       kill(pid, SIGUSR1);
+               }
+       }
+}
 
 /**
  * Handler for signals.
@@ -57,28 +87,44 @@ void sig_handler(int signo)
 {
        fprintf(stderr, "[%s] Received %s!\n", "process2", strsignal(signo));
        if (signo == SIGUSR1) {
+               fprintf(stderr, "[%s] > Notified!\n", "process2");
+               struct queue_message msg;
+               /* Check queues from both other processes */
+               if (msgrcv(qid, &msg, sizeof(int), 2, 0) > 0) {
+                       fprintf(stderr, "[%s] > Notified with value: %s!\n", "process2", strsignal(msg.signo[0]));
+                       raise(msg.signo[0]);
+               }
+               else if (msgrcv(qid, &msg, sizeof(int), 2, 0) > 0) {
+                       fprintf(stderr, "[%s] > Notified with value: %s!\n", "process2", strsignal(msg.signo[0]));
+                       raise(msg.signo[0]);
+               }
        }
        else if (signo == SIGTERM) {
-               int i = 0;
+               fprintf(stderr, "[%s] > Signalling other processes..\n", "process2");
+               processes->pids[1] = 0;
+               notify_other_processes(signo);
+
                fprintf(stderr, "[%s] > Releasing resources\n", "process2");
                close(read_descriptor);
                close(write_descriptor);
                unlink(write_descriptor);
-               for (; i < 3; i++) {
-                       fprintf(stderr, "[%s] Process %d, PID: %d\n", "process3", i, processes->pids[i]);
-               }
                exit(0);
        }
        else if (signo == SIGTSTP) {
-               fprintf(stderr, "[%s] > Closing pipes\n", "process2");
+               fprintf(stderr, "[%s] > Close reading pipe\n", "process2");
                close(read_descriptor);
+               notify_other_processes(signo);
+               fprintf(stderr, "[%s] > Close writing pipe\n", "process2");
                close(write_descriptor);
                raise (SIGSTOP);
        }
        else if (signo == SIGCONT) {
+               fprintf(stderr, "[%s] > Signalling other processes..\n", "process2");
+               notify_other_processes(signo);
+
                fprintf(stderr, "[%s] > Opening pipes\n", "process2");
-               read_descriptor = open(read_pipe, O_RDONLY);
                write_descriptor = open(write_pipe, O_WRONLY);
+               read_descriptor = open(read_pipe, O_RDONLY);
        }
 }
 
@@ -125,11 +171,18 @@ int main(void) {
         * Register memory to share with other processes, and pass current
         * process id to the array.
         */
-       shmid = shmget(shmkey, sizeof(struct message), IPC_CREAT | 0666);
+       shmid = shmget(shmkey, sizeof(struct message), 0666);
 
        processes = (struct message *)shmat(shmid, NULL, 0);
        processes->pids[1] = getpid();
 
+       fprintf(stderr, "[%s] Shared pid: %d\n", "process2", getpid());
+
+       /**
+        * Register message queue to communicate with other processes
+        */
+       qid = msgget(qkey, 0666);
+
        /* Reading from process1 */
        read_descriptor = open(read_pipe, O_RDONLY);