/* open/read/write/close */
#include <fcntl.h>
+/* Signals handling.. */
+#include <signal.h>
+
+#include <sys/shm.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;
+
+/**
+ * Handler for signals.
+ */
+void sig_handler(int signo)
+{
+ fprintf(stderr, "[%s] Received %s!\n", "process1", strsignal(signo));
+ if (signo == SIGUSR1) {
+ }
+ else if (signo == SIGTERM) {
+ int i = 0;
+ fprintf(stderr, "[%s] > Releasing resources\n", "process1");
+ close(write_pipe);
+ unlink(write_pipe);
+
+ if (buffer) {
+ free(buffer);
+ buffer = NULL;
+ }
+ for (; i < 3; i++) {
+ fprintf(stderr, "[%s] Process %d, PID: %d\n", "process3", i, processes->pids[i]);
+ }
+ 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.
/** Currently fetched from stdin character */
int c;
- /** Buffer used to store line of characters */
- char * buffer = NULL;
-
/** Current buffer length*/
int buffer_length = 0;
*/
char * tmp = NULL;
- /** Named pipe used to communnicate with process2 */
- char * write_pipe = "/tmp/process1pipe";
+ 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);
- /** File descriptor of pipe */
- int file_descriptor;
+ processes = (struct message *)shmat(shmid, NULL, 0);
+ processes->pids[0] = getpid();
mkfifo(write_pipe, 0666);
file_descriptor = open(write_pipe, O_WRONLY);
- fprintf(stderr, "[%s] Init!\n", "process1");
-
do {
c = fgetc(stdin);
}
} while(c != EOF);
+ /* Release resources in normal program flow exit. */
close(write_pipe);
unlink(write_pipe);