X-Git-Url: https://git.dlugolecki.net.pl/?a=blobdiff_plain;f=src%2Fprocess3.c;h=b1b997212be53430306b69232a3c88bd7d2f3b14;hb=f0a7f7a71896b25cc524598e5472c821f987a71c;hp=8b4f8264f39a3621f6dc0f267b6f53e8339e0f63;hpb=c0975e5a6af7b478563193dac7c3484b4430d3a3;p=wsti_so.git

diff --git a/src/process3.c b/src/process3.c
index 8b4f826..b1b9972 100644
--- a/src/process3.c
+++ b/src/process3.c
@@ -1,27 +1,71 @@
 #include <stdio.h>
 
+/* exit.. */
+#include <stdlib.h>
+
 /* open/read/write/close */
 #include <fcntl.h>
 
 /* 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;
+
+
+/**
+ * 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;
+
+
 /**
  * Handler for signals.
  */
 void sig_handler(int signo)
 {
+	fprintf(stderr, "[%s] Received %s!\n", "process3", strsignal(signo));
 	if (signo == SIGUSR1) {
-		fprintf(stderr, "[%s] SIGUSR1!\n", "process1");
 	}
-	else if (signo == SIGUSR2) {
-		fprintf(stderr, "[%s] SIGUSR2!\n", "process1");
+	else if (signo == SIGTERM) {
+		int i = 0;
+		fprintf(stderr, "[%s] > Releasing resources\n", "process3");
+		close(read_descriptor);
+		for (; i < 3; i++) {
+			fprintf(stderr, "[%s] Process %d, PID: %d\n", "process3", i, processes->pids[i]);
+		}
+		exit(0);
 	}
-	else if (signo == SIGINT) {
-		fprintf(stderr, "[%s] SIGINT!\n", "process1");
+	else if (signo == SIGTSTP) {
+		fprintf(stderr, "[%s] > Closing pipe\n", "process3");
+		close(read_descriptor);
+		raise (SIGSTOP);
 	}
 	else if (signo == SIGCONT) {
-		fprintf(stderr, "[%s] SIGCONT!\n", "process1");
+		fprintf(stderr, "[%s] > Opening pipe\n", "process3");
+		read_descriptor = open(read_pipe, O_RDONLY);
 	}
 }
 
@@ -30,12 +74,6 @@ void sig_handler(int signo)
  * grabbed data to the standard output.
  */
 int main(void) {
-	/** Named pipe used to communicate with process2 */
-	char * read_pipe = "/tmp/process2pipe";
-
-	/** Descriptor of input pipe */
-	int read_descriptor;
-
 	/** Buffer used for storing data from input pipe */
 	int buffer = 0;
 	
@@ -50,16 +88,25 @@ int main(void) {
 	if (signal(SIGUSR1, sig_handler) == SIG_ERR) {
 		fprintf(stderr, "can't catch SIGUSR1\n");
 	}
-	if (signal(SIGUSR2, sig_handler) == SIG_ERR) {
-		fprintf(stderr, "can't catch SIGUSR2\n");
+	if (signal(SIGTERM, sig_handler) == SIG_ERR) {
+		fprintf(stderr, "can't catch SIGTERM\n");
 	}
-	if (signal(SIGINT, sig_handler) == SIG_ERR) {
-		fprintf(stderr, "can't catch SIGINT\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();
+
 	/* Reading from process2 */
 	read_descriptor = open(read_pipe, O_RDONLY);
 
@@ -77,6 +124,7 @@ int main(void) {
 		}
 	}
 
+	/* Release resources in normal program flow exit. */
 	close(read_descriptor);
 
 	return 0;