X-Git-Url: https://git.dlugolecki.net.pl/?a=blobdiff_plain;f=src%2Fprocess2.c;h=87871e78675ecf56fa35ee9a4df9ab2712c667e7;hb=621bd5704dfeeccf51097ba255010bd37054972c;hp=4309e0c2a35fac44a62a4d0fd62bc0d58b6b0b14;hpb=eb58b0955c4340aafb4508e9c269b3216b2c1c1f;p=wsti_so.git

diff --git a/src/process2.c b/src/process2.c
index 4309e0c..87871e7 100644
--- a/src/process2.c
+++ b/src/process2.c
@@ -1,61 +1,123 @@
 #include <stdio.h>
+/* exit.. */
 #include <stdlib.h>
-#include <string.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);
+	}
+	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";
-
-	int read_descriptor;
-	int write_descriptor;
-	
+	/**
+	 * Buffer used for storing data from input pipe.
+	 * Data is stored in chunks of BUFFER_STEP size.
+	 * If data during reading is bigger than this value, then number of
+	 * characters is saved, and buffer is cleared for reading another chunk.
+	 */
 	char buffer[BUFFER_STEP];
-	
+
+	/** Index used when iterating buffer */
 	int i = 0;
+
+	/** 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);
 
 	/* Writing to process2 */
 	mkfifo(write_pipe, 0666);
 	write_descriptor = open(write_pipe, O_WRONLY);
-	
-	int number_of_characters = 0;
-	
-	do {
+
+	while(1) {
 		/* Read data from input pipe */
 		count = read(read_descriptor, buffer, BUFFER_STEP);
 
-		printf("fetched: %d bytes\n", count);
+		fprintf(stderr, "[%s] Fetched: %d bytes\n", "process2", count);
 
 		if (count > 0) {
-			int j = 0;
-			for (; j < count; j++, number_of_characters++) {
-				if (buffer[j] == '\n') {
-					fprintf(stderr, "Writting about: %d\n", number_of_characters);
-					write(write_descriptor, number_of_characters, sizeof(number_of_characters));
+			for (i = 0; i < count; i++, number_of_characters++) {
+				if (buffer[i] == '\n') {
+					fprintf(stderr, "[%s] Calculated: %d characters. Sending...\n", "process2", number_of_characters);
+					write(write_descriptor, &number_of_characters, sizeof(number_of_characters));
 					write(write_descriptor, '\n', 1);
 					number_of_characters = 0;
 				}
 			}
-
 		}
-	} while(count > 0);
+		else {
+			break;
+		}
+	}
 
+	/* Release resources in normal program flow exit. */
 	close(read_descriptor);
 	close(write_descriptor);
 	unlink(write_descriptor);