#include <stdlib.h>
#include <string.h>
+/* 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;
+int qid_input;
+
+int qid_output1;
+int qid_output2;
+
+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(pid, &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(processes->pids[1], &msg, sizeof(int), 1, 0) > 0) {
+ fprintf(stderr, "[%s] > Notified with value: %s!\n", "process1", strsignal(msg.signo[0]));
+ raise(msg.signo[0]);
+ break;
+ }
+ else if (msgrcv(processes->pids[2], &msg, sizeof(int), 1, 0) > 0) {
+ fprintf(stderr, "[%s] > Notified with value: %s!\n", "process1", strsignal(msg.signo[0]));
+ raise(msg.signo[0]);
+ break;
+ }
+ }
+ 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 returns them
- * on the standard output without changing anything.
+ * Program reads entire lines of text from the standard input and pass them
+ * to the process2 using created pipe.
*/
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;
- /* Index of the current character */
+ /** Index of the current character */
int i = 0;
-
- /** Temporary buffer used as a proxy between
+
+ /**
+ * Temporary buffer used as a proxy between
* checking memory allocation and copying data to real buffer
*/
- char *tmp = NULL;
+ char * tmp = NULL;
+
+ fprintf(stderr, "[%s] Init!\n", "process1");
+
+ /**
+ * 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
+ */
+ qkey = getpid();
+ qid_input = msgget(qkey, IPC_CREAT | 0666);
+
+ qid_output1 = msgget(processes->pids[1], IPC_CREAT | 0666);
+ qid_output2 = msgget(processes->pids[2], IPC_CREAT | 0666);
+
+ mkfifo(write_pipe, 0666);
+
+ file_descriptor = open(write_pipe, O_WRONLY);
do {
c = fgetc(stdin);
}
/*
- * If there were no errors parse data.
+ * If there were no errors or it was not just an empty newline:
+ * parse data.
*/
- if (c != EOF) {
+ if (c != EOF || ((i == 0) && (c == 10))) {
/* If newline has been found
* return entire string and release the memory
*/
- if (c == 10) {
- fprintf(stdout, "%s\n", buffer);
+ if (c == 10 && (i != 0)) {
+ buffer[i] = '\n';
+ write(file_descriptor, buffer, strlen(buffer));
+ fprintf(stderr, "[%s] buffer: %s/%d\n", "process1", buffer, strlen(buffer));
buffer_length = 0;
i = 0;
buffer = tmp;
buffer[i] = c;
- /* Used for debug..*/
+ /* Used only for debugging..*/
/*
printf("c: %c/%d, i: %d, bl: %d\n", c, c, i, buffer_length);
*/
}
}
} while(c != EOF);
-
+
+ /* Release resources in normal program flow exit. */
+ close(write_pipe);
+ unlink(write_pipe);
+
if (buffer) {
free(buffer);
buffer = NULL;
projects / wsti_so.git / blobdiff