X-Git-Url: https://git.dlugolecki.net.pl/?a=blobdiff_plain;f=src%2Fprocess2.c;h=861919ce8b45b606fc11579ace0f6de0de3030e3;hb=963f77561737c9098d160a4b1d308c71ab0fdef8;hp=87871e78675ecf56fa35ee9a4df9ab2712c667e7;hpb=621bd5704dfeeccf51097ba255010bd37054972c;p=wsti_so.git

diff --git a/src/process2.c b/src/process2.c
index 87871e7..861919c 100644
--- 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>
@@ -8,6 +10,8 @@
 /* Signals handling.. */
 #include <signal.h>
 
+#include <sys/shm.h>
+
 /** If buffer is too small to hold entire string, it is incremented by this value */
 #define BUFFER_STEP 16
 
@@ -23,6 +27,59 @@ int read_descriptor;
 /** Descriptor of output pipe */
 int write_descriptor;
 
+
+/**
+ * Shared memory variables
+ */
+
+/**
+ * Memory key for processes. Must be same between all processes to properly
+ * communicate.
+ */
+key_t shmkey = 18912;
+/**
+ * Id of the shared memory
+ */
+int shmid;
+
+/**
+ * Message shared by processes. Contains array of process IDs
+ */
+struct message {
+	pid_t pids[3];
+};
+
+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.
  */
@@ -30,8 +87,23 @@ 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) {
+		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);
@@ -39,14 +111,20 @@ void sig_handler(int signo)
 		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);
 	}
 }
 
@@ -89,6 +167,22 @@ int main(void) {
 		fprintf(stderr, "can't catch SIGCONT\n");
 	}
 
+	/*
+	 * Register memory to share with other processes, and pass current
+	 * process id to the array.
+	 */
+	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);