Remove not used conditional.

[wsti_so.git] / src / process1.c

diff --git a/src/process1.c b/src/process1.c
index d514b03e38daa000c379cc21e9c43212576eb2c6..601c356643e08bc3d297ff0ec621dc75e700fe3f 100644 (file)
--- a/src/process1.c
+++ b/src/process1.c
@@ -5,9 +5,118 @@
 /* open/read/write/close */
 #include <fcntl.h>
 
+/* Signals handling.. */
+#include <signal.h>
+
+#include <sys/shm.h>
+#include <sys/msg.h>
+
+
 /** If buffer is too small to hold entire string, it is incremented by this value */
 #define BUFFER_STEP 16
 
+/** Buffer used to store line of characters */
+char * buffer = NULL;
+
+/** Named pipe used to communnicate with process2 */
+char * write_pipe = "/tmp/process1pipe";
+
+/** File descriptor of pipe */
+int file_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;
+
+/**
+ * Message queue variables
+ */
+key_t qkey = 12356;
+int qid;
+
+struct queue_message {
+       long mtype;
+       int signo[1];
+};
+
+void notify_other_processes(int signo) {
+       int i = 0;
+       struct queue_message msg;
+       msg.signo[0] = signo;
+
+       for (; i < 3; i++) {
+               pid_t pid = processes->pids[i];
+               // Bleh
+               if (i != 0 && pid != 0) {
+                       msg.mtype = i+1;
+                       fprintf(stderr, "[%s] Sending message of type (%d) with value %d\n", "process1", msg.mtype, msg.signo[0]);
+                       msgsnd(qid, &msg, sizeof(int), 0);
+                       fprintf(stderr, "[%s] Sending signal %s (%d) to PID: %d\n", "process1", strsignal(SIGUSR1), SIGUSR1, pid);
+                       kill(pid, SIGUSR1);
+               }
+       }
+}
+
+/**
+ * Handler for signals.
+ */
+void sig_handler(int signo)
+{
+       fprintf(stderr, "[%s] Received %s!\n", "process1", strsignal(signo));
+       if (signo == SIGUSR1) {
+               fprintf(stderr, "[%s] > Notified!\n", "process1");
+               struct queue_message msg;
+               /* Check queues from both other processes */
+               if (msgrcv(qid, &msg, sizeof(int), 1, 0) > 0) {
+                       fprintf(stderr, "[%s] > Notified with value: %s!\n", "process1", strsignal(msg.signo[0]));
+                       raise(msg.signo[0]);
+               }
+       }
+       else if (signo == SIGTERM) {
+               fprintf(stderr, "[%s] > Signalling other processes..\n", "process1");
+               processes->pids[1] = 0;
+               notify_other_processes(signo);
+
+               fprintf(stderr, "[%s] > Releasing resources\n", "process1");
+               close(write_pipe);
+               unlink(write_pipe);
+
+               if (buffer) {
+                       free(buffer);
+                       buffer = NULL;
+               }
+               exit(0);
+       }
+       else if (signo == SIGTSTP) {
+               fprintf(stderr, "[%s] > Closing pipe\n", "process1");
+               close(write_pipe);
+               raise (SIGSTOP);
+       }
+       else if (signo == SIGCONT) {
+               fprintf(stderr, "[%s] > Opening pipe\n", "process1");
+               file_descriptor = open(write_pipe, O_WRONLY);
+       }
+}
+
 /**
  * Program reads entire lines of text from the standard input and pass them
  * to the process2 using created pipe.
@@ -16,9 +125,6 @@ int main(void) {
        /** Currently fetched from stdin character */
        int c;
 
-       /** Buffer used to store line of characters */
-       char * buffer = NULL;
-
        /** Current buffer length*/
        int buffer_length = 0;
 
@@ -31,18 +137,44 @@ int main(void) {
         */
        char * tmp = NULL;
 
-       /** Named pipe used to communnicate with process2 */
-       char * write_pipe = "/tmp/process1pipe";
+       fprintf(stderr, "[%s] Init!\n", "process1");
 
-       /** File descriptor of pipe */
-       int file_descriptor;
+       /**
+        * 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");
+       }
+
+       /*
+        * 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[0] = getpid();
+
+       fprintf(stderr, "[%s] Shared pid: %d\n", "process1", getpid());
+
+       /**
+        * Register message queue to communicate with other processes
+        */
+       qid = msgget(qkey, IPC_CREAT | 0666);
+       
        mkfifo(write_pipe, 0666);
 
        file_descriptor = open(write_pipe, O_WRONLY);
 
-       fprintf(stderr, "[%s] Init!\n", "process1");
-
        do {
                c = fgetc(stdin);
 
@@ -99,6 +231,7 @@ int main(void) {
                }
        } while(c != EOF);
 
+       /* Release resources in normal program flow exit. */
        close(write_pipe);
        unlink(write_pipe);