First thing, thanks for reading and trying to help!
In the following code it is meant to create 5 Worker Processes and be listening (read) some information from a unnamed pipes that is passed as an argument (that means the unnamed pipe is fixed to that Worker Process), the program also creates a single threat named Dispatcher, the thread is meant to send information (write) to all unnamed pipes so the Worker Process can read the information and print it out. The unnamed pipes are stored in a array dispatcher_pipes.
First I wrote information into the unnamed pipes in the main function and it worked, the Worker Process printed the information I wrote in the unnamed pipes, but when I tried to implement that function to the dispacher threat it didnt work.
Here is the current code that doesnt work
NOTE: I compile the code in the linux terminal with gcc
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <pthread.h>
typedef struct msgbuf {
long mtype; // if 0 it did not pass in no process, 1 - worker, 2 - alert watcher
char mtext[100];
}msgbuf;
int n_workers = 5;
pid_t *pid_workers;
void* dispatcher(void *args) {
int (*dispatcher_pipe)[2] = (int (*)[2])args;
pthread_t id=pthread_self();
printf("Dispatcher thread started.\n");
msgbuf send_msg;
send_msg.mtype = 0;
strcpy(send_msg.mtext, "Message from Dispatcher");
for (int i = 0; i < n_workers; i++) {
close(dispatcher_pipe[i][0]); // Close the read end of the pipe
write(dispatcher_pipe[i][1], &send_msg, sizeof(msgbuf));
close(dispatcher_pipe[i][1]); // Close the write end of the pipe
}
usleep(10); // simulates the processing of the order
printf("Thread %ld: Worker finishing\n",id);
pthread_exit(NULL);
}
void Worker(int *worker_pipe){
// Register the signal handler for SIGUSR1
//signal(SIGUSR1, sigint);
printf("Worker Process (PID=%d): starting!\n",getpid());
//printf("child getppid() :%ld\n", (long)getppid());
//sleep(5);
//Getting message from Dispatcher
close(worker_pipe[1]); // Close the write end of the pipe
msgbuf rec_msg;
read(worker_pipe[0], rec_msg.mtext, sizeof(msgbuf));
printf("Worker message received from Dispatcher: %s\n", rec_msg.mtext);
close(worker_pipe[0]); // Close the read end of the pipe
sleep(1);
//this exit is only here for debugging purpose as well on the other processes, change it to kill like
printf("\nWorker process %d has died.\n", getpid());
exit(0);
}
void main(){
//variables for the threads
//pthread_t system_threads[3];
pthread_t console_thread, sensor_thread, dispatcher_thread;
//variable for unnamed pipes
int dispatcher_pipe[n_workers][2];
pid_workers= malloc(n_workers * sizeof(pid_t));
//Creates the unnamed pipes for dispatcher
for(int i=0;i<n_workers;i++){
if(pipe(dispatcher_pipe[i]) == -1){
printf("Error creating dispatcher pipe n1\n");
exit(0);
}
}
//Creating Worker Processes
for(int i=0;i<n_workers;i++){
pid_workers[i] = fork();
if (pid_workers[i] == 0) {
//Child process
//printf("YO IM A CHILD\n");
Worker(dispatcher_pipe[i]);
//printf("Hey\n");
} else if (pid_workers[i] > 0) {
//Parent process
//printf("YO IM A FADER\n");
} else {
//Error forking
perror("fork");
exit(EXIT_FAILURE);
}
}
//Creating Threads
pthread_create(&dispatcher_thread, NULL, dispatcher, dispatcher_pipe); // ATENCAO arg fica NULL?
//Wait for the threads to finish
pthread_join(dispatcher_thread, NULL);
}
Here is the code that worked without the unnamed pipes beind written in the dispatcher thread
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <pthread.h>
typedef struct msgbuf {
long mtype;
char mtext[100];
}msgbuf;
int n_workers = 5;
pid_t *pid_workers;
void* dispatcher(void *args) {
int (*dispatcher_pipe)[2] = (int (*)[2])args;
pthread_t id=pthread_self();
printf("Dispatcher thread started.\n");
for(int i=0;i<n_workers;i++){
close(dispatcher_pipe[i][0]); // Close the read end of the pipe
msgbuf send_msg;
send_msg.mtype = 1;
snprintf(send_msg.mtext, sizeof(send_msg.mtext), "Message from SystemManager to Worker %d", i);
write(dispatcher_pipe[i][1], send_msg.mtext, sizeof(send_msg.mtext));
close(dispatcher_pipe[i][1]); // Close the write end of the pipe
}
usleep(10); // simulates the processing of the order
printf("Thread %ld: Worker finishing\n",id);
pthread_exit(NULL);
}
void Worker(int *worker_pipe){
// Register the signal handler for SIGUSR1
//signal(SIGUSR1, sigint);
printf("Worker Process (PID=%d): starting!\n",getpid());
//printf("child getppid() :%ld\n", (long)getppid());
//sleep(5);
//Getting message from Dispatcher
close(worker_pipe[1]); // Close the write end of the pipe
msgbuf rec_msg;
read(worker_pipe[0], rec_msg.mtext, sizeof(msgbuf));
printf("Worker message received from Dispatcher: %s\n", rec_msg.mtext);
close(worker_pipe[0]); // Close the read end of the pipe
sleep(1);
//this exit is only here for debugging purpose as well on the other processes, change it to kill like
printf("\nWorker process %d has died.\n", getpid());
exit(0);
}
void main(){
//variables for the threads
//pthread_t system_threads[3];
pthread_t console_thread, sensor_thread, dispatcher_thread;
//variable for unnamed pipes
int dispatcher_pipe[n_workers][2];
pid_workers= malloc(n_workers * sizeof(pid_t));
//Creates the unnamed pipes for dispatcher
for(int i=0;i<n_workers;i++){
if(pipe(dispatcher_pipe[i]) == -1){
printf("Error creating dispatcher pipe n1\n");
exit(0);
}
}
//Creating Worker Processes
for(int i=0;i<n_workers;i++){
pid_workers[i] = fork();
if (pid_workers[i] == 0) {
//Child process
//printf("YO IM A CHILD\n");
Worker(dispatcher_pipe[i]);
//printf("Hey\n");
} else if (pid_workers[i] > 0) {
//Parent process
//printf("YO IM A FADER\n");
} else {
//Error forking
perror("fork");
exit(EXIT_FAILURE);
}
}
}
