X-Git-Url: https://git.dlugolecki.net.pl/?a=blobdiff_plain;f=src%2Fprocess3.c;h=54bb6587370a53648f0aecbc63a6e2b299ec5176;hb=b1c3c5ca4ac63d8e7f92cc130a75d2322b8a28d8;hp=d5be26a12c2088dfe48748cb46ed1785757e5ae1;hpb=05e20db49d95955f0f00f546a7d02e4df023b805;p=wsti_so.git

diff --git a/src/process3.c b/src/process3.c
index d5be26a..54bb658 100644
--- a/src/process3.c
+++ b/src/process3.c
@@ -1,33 +1,149 @@
 #include <stdio.h>
+
+/* exit.. */
 #include <stdlib.h>
-#include <string.h>
 
 /* open/read/write/close */
 #include <fcntl.h>
 
-/** If buffer is too small to hold entire string, it is incremented by this value */
-#define BUFFER_STEP 16
+/* Signals handling.. */
+#include <signal.h>
+
+#include <sys/shm.h>
+
+/** Named pipe used to communicate with process2 */
+char * read_pipe = "/tmp/process2pipe";
+
+/** Descriptor of input pipe */
+int read_descriptor;
+
 
 /**
- * Program grabs data from process1, calculates number of characters in each line
- * and pass the value to process3.
+ * Shared memory variables
  */
-int main(void) {
-	/** Named pipe used to communicate with process1 */
-	char * read_pipe = "/tmp/process2pipe";
+/**
+ * Memory key for processes. Must be same between all processes to properly
+ * communicate.
+ */
+key_t shmkey = 18912;
+/**
+ * Id of the shared memory
+ */
+int shmid;
 
-	int read_descriptor;
-	
+/**
+ * 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;
+int qid_input;
+
+int qid_output1;
+int qid_output2;
+
+struct queue_message {
+	int signo;
+};
+
+/**
+ * Handler for signals.
+ */
+void sig_handler(int signo)
+{
+	fprintf(stderr, "[%s] Received %s!\n", "process3", strsignal(signo));
+	if (signo == SIGUSR1) {
+		fprintf(stderr, "[%s] > Notified!\n", "process3");
+	}
+	else if (signo == SIGTERM) {
+		int i = 0;
+		struct queue_message msg;
+		msg.signo = signo;
+
+		fprintf(stderr, "[%s] > Releasing resources\n", "process3");
+		close(read_descriptor);
+		for (; i < 3; i++) {
+			pid_t pid = processes->pids[i];
+			fprintf(stderr, "[%s] Process %d, PID: %d\n", "process3", i, pid);
+			// Bleh
+			if (i != 2) {
+				msgsnd(pid, &msg, sizeof(msg));
+				kill(pid, SIGUSR1);
+			}
+		}
+		exit(0);
+	}
+	else if (signo == SIGTSTP) {
+		fprintf(stderr, "[%s] > Closing pipe\n", "process3");
+		close(read_descriptor);
+		raise (SIGSTOP);
+	}
+	else if (signo == SIGCONT) {
+		fprintf(stderr, "[%s] > Opening pipe\n", "process3");
+		read_descriptor = open(read_pipe, O_RDONLY);
+	}
+}
+
+/**
+ * Program grabs data (calculated number of characters) from process2 and prints
+ * grabbed data to the standard output.
+ */
+int main(void) {
+	/** Buffer used for storing data from input pipe */
 	int buffer = 0;
 	
-	int i = 0;
+	/** Stores number of bytes read from input pipe in current iteration */
 	ssize_t count = 0;
 
+	fprintf(stderr, "[%s] Init!\n", "process3");
+
+	/**
+	 * 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[2] = getpid();
+
+	fprintf(stderr, "[%s] Shared pid: %d\n", "process3", getpid());
+
+	sleep(1);
+	/**
+	 * Register message queue to communicate with other processes
+	 */
+	qkey = getpid();
+	qid_input = msgget(qkey, IPC_CREAT | 0666);
+	
+	qid_output1 = msgget(processes->pids[1], IPC_CREAT | 0666);
+	qid_output2 = msgget(processes->pids[2], IPC_CREAT | 0666);
+
 	/* Reading from process2 */
 	read_descriptor = open(read_pipe, O_RDONLY);
 
-	int number_of_characters = 0;
-	
 	while(1) {
 		/* Read data from input pipe */
 		count = read(read_descriptor, &buffer, sizeof(int));
@@ -42,6 +158,7 @@ int main(void) {
 		}
 	}
 
+	/* Release resources in normal program flow exit. */
 	close(read_descriptor);
 
 	return 0;