X-Git-Url: https://git.dlugolecki.net.pl/?a=blobdiff_plain;f=src%2Fprocess1.c;h=601c356643e08bc3d297ff0ec621dc75e700fe3f;hb=36fddb02ae4b75d5671cb859be2706e640311737;hp=f4a1392d84398e72d440e0d63cfb6b64690b46a7;hpb=05e20db49d95955f0f00f546a7d02e4df023b805;p=wsti_so.git

diff --git a/src/process1.c b/src/process1.c
index f4a1392..601c356 100644
--- a/src/process1.c
+++ b/src/process1.c
@@ -5,9 +5,118 @@
 /* open/read/write/close */
 #include <fcntl.h>
 
+/* Signals handling.. */
+#include <signal.h>
+
+#include <sys/shm.h>
+#include <sys/msg.h>
+
+
 /** If buffer is too small to hold entire string, it is incremented by this value */
 #define BUFFER_STEP 16
 
+/** Buffer used to store line of characters */
+char * buffer = NULL;
+
+/** Named pipe used to communnicate with process2 */
+char * write_pipe = "/tmp/process1pipe";
+
+/** File descriptor of pipe */
+int file_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 != 0 && 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(int), 0);
+			fprintf(stderr, "[%s] Sending signal %s (%d) to PID: %d\n", "process1", strsignal(SIGUSR1), SIGUSR1, pid);
+			kill(pid, SIGUSR1);
+		}
+	}
+}
+
+/**
+ * Handler for signals.
+ */
+void sig_handler(int signo)
+{
+	fprintf(stderr, "[%s] Received %s!\n", "process1", strsignal(signo));
+	if (signo == SIGUSR1) {
+		fprintf(stderr, "[%s] > Notified!\n", "process1");
+		struct queue_message msg;
+		/* Check queues from both other processes */
+		if (msgrcv(qid, &msg, sizeof(int), 1, 0) > 0) {
+			fprintf(stderr, "[%s] > Notified with value: %s!\n", "process1", strsignal(msg.signo[0]));
+			raise(msg.signo[0]);
+		}
+	}
+	else if (signo == SIGTERM) {
+		fprintf(stderr, "[%s] > Signalling other processes..\n", "process1");
+		processes->pids[1] = 0;
+		notify_other_processes(signo);
+
+		fprintf(stderr, "[%s] > Releasing resources\n", "process1");
+		close(write_pipe);
+		unlink(write_pipe);
+
+		if (buffer) {
+			free(buffer);
+			buffer = NULL;
+		}
+		exit(0);
+	}
+	else if (signo == SIGTSTP) {
+		fprintf(stderr, "[%s] > Closing pipe\n", "process1");
+		close(write_pipe);
+		raise (SIGSTOP);
+	}
+	else if (signo == SIGCONT) {
+		fprintf(stderr, "[%s] > Opening pipe\n", "process1");
+		file_descriptor = open(write_pipe, O_WRONLY);
+	}
+}
+
 /**
  * Program reads entire lines of text from the standard input and pass them
  * to the process2 using created pipe.
@@ -16,9 +125,6 @@ int main(void) {
 	/** Currently fetched from stdin character */
 	int c;
 
-	/** Buffer used to store line of characters */
-	char * buffer = NULL;
-
 	/** Current buffer length*/
 	int buffer_length = 0;
 
@@ -31,16 +137,44 @@ int main(void) {
 	 */
 	char * tmp = NULL;
 
-	/** Named pipe used to communnicate with process2 */
-	char * write_pipe = "/tmp/process1pipe";
+	fprintf(stderr, "[%s] Init!\n", "process1");
 
-	/** File descriptor of pipe */
-	int file_descriptor;
+	/**
+	 * Register signals handled by process
+	 */
+	if (signal(SIGUSR1, sig_handler) == SIG_ERR) {
+		fprintf(stderr, "can't catch SIGUSR1\n");
+	}
+	if (signal(SIGTERM, sig_handler) == SIG_ERR) {
+		fprintf(stderr, "can't catch SIGTERM\n");
+	}
+	if (signal(SIGTSTP, sig_handler) == SIG_ERR) {
+		fprintf(stderr, "can't catch SIGTSTP\n");
+	}
+	if (signal(SIGCONT, sig_handler) == SIG_ERR) {
+		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), IPC_CREAT | 0666);
+
+	processes = (struct message *)shmat(shmid, NULL, 0);
+	processes->pids[0] = getpid();
 
+	fprintf(stderr, "[%s] Shared pid: %d\n", "process1", getpid());
+
+	/**
+	 * Register message queue to communicate with other processes
+	 */
+	qid = msgget(qkey, IPC_CREAT | 0666);
+	
 	mkfifo(write_pipe, 0666);
 
 	file_descriptor = open(write_pipe, O_WRONLY);
-	
+
 	do {
 		c = fgetc(stdin);
 
@@ -88,7 +222,7 @@ int main(void) {
 				buffer = tmp;
 				buffer[i] = c;
 
-				/* Used for debug..*/
+				/* Used only for debugging..*/
 				/*
 				printf("c: %c/%d, i: %d, bl: %d\n", c, c, i, buffer_length);
 				*/
@@ -97,6 +231,7 @@ int main(void) {
 		}
 	} while(c != EOF);
 
+	/* Release resources in normal program flow exit. */
 	close(write_pipe);
 	unlink(write_pipe);