X-Git-Url: https://git.dlugolecki.net.pl/?a=blobdiff_plain;f=src%2Fprocess2.c;h=49081737183fa6d1fc98faf725daed73a78d09bc;hb=717e5b533ec94ef8f9a703bd4f019a2f45e138df;hp=b6dff4b8d2fa0703405cf9ee49e97793ee01d5e3;hpb=51faabd1c82aa37c43f6521ae17c47ce62272754;p=wsti_so.git

diff --git a/src/process2.c b/src/process2.c
index b6dff4b..4908173 100644
--- a/src/process2.c
+++ b/src/process2.c
@@ -1,28 +1,61 @@
 #include <stdio.h>
+/* exit.. */
+#include <stdlib.h>
 
 /* open/read/write/close */
 #include <fcntl.h>
 
+/* Signals handling.. */
+#include <signal.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;
+
+/**
+ * Handler for signals.
+ */
+void sig_handler(int signo)
+{
+	fprintf(stderr, "[%s] Received %s!\n", "process2", strsignal(signo));
+	if (signo == SIGUSR1) {
+	}
+	else if (signo == SIGTERM) {
+		fprintf(stderr, "[%s] > Releasing resources\n", "process2");
+		close(read_descriptor);
+		close(write_descriptor);
+		unlink(write_descriptor);
+		exit(0);
+	}
+	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] > Opening pipes\n", "process2");
+		read_descriptor = open(read_pipe, O_RDONLY);
+		write_descriptor = open(write_pipe, O_WRONLY);
+	}
+}
+
 /**
  * Program grabs data from process1, calculates number of characters in each line
  * 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.
@@ -37,6 +70,26 @@ int main(void) {
 	/** Stores number of bytes read from input pipe in current iteration */
 	ssize_t count = 0;
 
+	int number_of_characters = 0;
+
+	fprintf(stderr, "[%s] Init!\n", "process2");
+
+	/**
+	 * 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");
+	}
+
 	/* Reading from process1 */
 	read_descriptor = open(read_pipe, O_RDONLY);
 
@@ -44,10 +97,6 @@ int main(void) {
 	mkfifo(write_pipe, 0666);
 	write_descriptor = open(write_pipe, O_WRONLY);
 
-	int number_of_characters = 0;
-
-	fprintf(stderr, "[%s] Init!\n", "process2");
-
 	while(1) {
 		/* Read data from input pipe */
 		count = read(read_descriptor, buffer, BUFFER_STEP);
@@ -69,6 +118,7 @@ int main(void) {
 		}
 	}
 
+	/* Release resources in normal program flow exit. */
 	close(read_descriptor);
 	close(write_descriptor);
 	unlink(write_descriptor);