Replace SIGQUIT with SIGTERM.

[wsti_so.git] / src / process2.c

diff --git a/src/process2.c b/src/process2.c
index 4309e0c2a35fac44a62a4d0fd62bc0d58b6b0b14..75dacfde993ab2fa3f29357ac1fa335896dd827a 100644 (file)
--- a/src/process2.c
+++ b/src/process2.c
@@ -1,61 +1,126 @@
 #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)
+{
+       if (signo == SIGUSR1) {
+               fprintf(stderr, "[%s] Received SIGUSR1!\n", "process2");
+       }
+       else if (signo == SIGTERM) {
+               fprintf(stderr, "[%s] Received SIGTERM!\n", "process2");
+               fprintf(stderr, "[%s] > Releasing resources\n", "process2");
+               close(read_descriptor);
+               close(write_descriptor);
+               unlink(write_descriptor);
+               exit(0);
+       }
+       else if (signo == SIGINT) {
+               fprintf(stderr, "[%s] Received SIGINT!\n", "process2");
+               fprintf(stderr, "[%s] > Closing pipes\n", "process2");
+               close(read_descriptor);
+               close(write_descriptor);
+       }
+       else if (signo == SIGCONT) {
+               fprintf(stderr, "[%s] Received SIGCONT!\n", "process2");
+               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(SIGINT, sig_handler) == SIG_ERR) {
+               fprintf(stderr, "can't catch SIGINT\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);