X-Git-Url: https://git.dlugolecki.net.pl/?a=blobdiff_plain;f=src%2Fprocess2.c;h=2417fe88638fd27bdc543a5d764bca6847540b87;hb=f0a7f7a71896b25cc524598e5472c821f987a71c;hp=7ae70ffc4a056bfd4dfaaa21278c3537f89438ba;hpb=c0975e5a6af7b478563193dac7c3484b4430d3a3;p=wsti_so.git

diff --git a/src/process2.c b/src/process2.c
index 7ae70ff..2417fe8 100644
--- a/src/process2.c
+++ b/src/process2.c
@@ -1,4 +1,6 @@
 #include <stdio.h>
+/* exit.. */
+#include <stdlib.h>
 
 /* open/read/write/close */
 #include <fcntl.h>
@@ -6,25 +8,77 @@
 /* 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
 
+/** Named pipe used to communicate with process1 */
+char * read_pipe = "/tmp/process1pipe";
+
+/** Named pipe used to communicate with process3 */
+char * write_pipe = "/tmp/process2pipe";
+
+/** Descriptor of input pipe */
+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;
+
+
 /**
  * Handler for signals.
  */
 void sig_handler(int signo)
 {
+	fprintf(stderr, "[%s] Received %s!\n", "process2", 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", "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 == SIGINT) {
-		fprintf(stderr, "[%s] SIGINT!\n", "process1");
+	else if (signo == SIGTSTP) {
+		fprintf(stderr, "[%s] > Closing pipes\n", "process2");
+		close(read_descriptor);
+		close(write_descriptor);
+		raise (SIGSTOP);
 	}
 	else if (signo == SIGCONT) {
-		fprintf(stderr, "[%s] SIGCONT!\n", "process1");
+		fprintf(stderr, "[%s] > Opening pipes\n", "process2");
+		read_descriptor = open(read_pipe, O_RDONLY);
+		write_descriptor = open(write_pipe, O_WRONLY);
 	}
 }
 
@@ -33,18 +87,6 @@ void sig_handler(int signo)
  * and pass the value to process3.
  */
 int main(void) {
-	/** Named pipe used to communicate with process1 */
-	char * read_pipe = "/tmp/process1pipe";
-
-	/** Named pipe used to communicate with process3 */
-	char * write_pipe = "/tmp/process2pipe";
-
-	/** Descriptor of input pipe */
-	int read_descriptor;
-
-	/** Descriptor of output pipe */
-	int write_descriptor;
-
 	/**
 	 * Buffer used for storing data from input pipe.
 	 * Data is stored in chunks of BUFFER_STEP size.
@@ -59,13 +101,6 @@ int main(void) {
 	/** Stores number of bytes read from input pipe in current iteration */
 	ssize_t count = 0;
 
-	/* Reading from process1 */
-	read_descriptor = open(read_pipe, O_RDONLY);
-
-	/* Writing to process2 */
-	mkfifo(write_pipe, 0666);
-	write_descriptor = open(write_pipe, O_WRONLY);
-
 	int number_of_characters = 0;
 
 	fprintf(stderr, "[%s] Init!\n", "process2");
@@ -76,16 +111,32 @@ 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[1] = getpid();
+
+	/* Reading from process1 */
+	read_descriptor = open(read_pipe, O_RDONLY);
+
+	/* Writing to process2 */
+	mkfifo(write_pipe, 0666);
+	write_descriptor = open(write_pipe, O_WRONLY);
+
 	while(1) {
 		/* Read data from input pipe */
 		count = read(read_descriptor, buffer, BUFFER_STEP);
@@ -107,6 +158,7 @@ int main(void) {
 		}
 	}
 
+	/* Release resources in normal program flow exit. */
 	close(read_descriptor);
 	close(write_descriptor);
 	unlink(write_descriptor);