so lab 2-5

// lab2
// hello.c

#include <unistd.h>

int main() {
    write(1, "Hello world\n", 13);
}

// mycp.c

#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>

int main(int argc, char **argv) {
    // struct stat *buff;
    // stat(argv[1], buff);
    // long int size = buff->st_size;

    int sursa = open(argv[1], O_RDONLY);
    char continut;

    int dest = open(argv[2], O_WRONLY | O_CREAT, S_IRUSR | S_IWUSR);

    while (read(sursa, &continut, 1)) {
        write(dest, &continut, 1);
    }

    close(sursa);
    close(dest);
}

// lab3

// forkls.c

#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>
#include <sys/wait.h>

int main() {
    pid_t pid = fork();
    if (pid < 0)
        return errno;
    else if (pid == 0) {
        printf("My PID=%d, child PID=%d\n", getppid(), getpid());

        char *argv[] = {"ls", NULL};
        execve("/usr/bin/ls", argv, NULL);
        perror(NULL);
    }
    else {
        pid_t childPid = wait(NULL);
        printf("Child %d finished\n", childPid);
    }
}

// collatz.c

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>
#include <sys/wait.h>

int main(int argc, char *argv[]) {
    pid_t pid = fork();
    if (pid < 0)
        return errno;
    else if (pid == 0) {
        int n = atoi(argv[1]);
        printf("%d: %d ", n, n);

        while (n != 1) {
            if (n % 2 == 0)
                n = n / 2;
            else
                n = 3 * n + 1;

            printf("%d ", n);
        }

    }
    else {
        pid_t childPid = wait(NULL);
        printf("\nChild %d finished\n", childPid);
    }
}

// ncollatz.c

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>
#include <sys/wait.h>

int main(int argc, char *argv[]) {
    pid_t parent = getpid();
    printf("Starting parent %d\n", parent);

    for (int i = 1; i < argc; i++) {
        pid_t child = fork();

        if (child < 0)
            return errno;
        else if (child == 0) {
            int n = atoi(argv[i]);
            printf("%d: %d ", n, n);

            while (n != 1) {
                if (n % 2 == 0)
                    n = n / 2;
                else
                    n = 3 * n + 1;

                printf("%d ", n);
            }
            printf("\n");
            return 0;
        }
    }

    for (int i = 1; i < argc; i++) {
        pid_t childf = wait(0);
        printf("Done Parent %d, Me %d\n", getpid(), childf);
    }
    printf("Done Parent %d, Me %d\n", getppid(), getpid());
}


// lab5
// shmcollatz.c

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>
#include <sys/wait.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <fcntl.h>

int main(int argc, char *argv[]) {
    pid_t parent = getpid();
    printf("Starting parent %d\n", parent);

    char shm_name[] = "myshm";
    int shm_fd = shm_open(shm_name, O_CREAT|O_RDWR, S_IRUSR|S_IWUSR);
    if (shm_fd < 0) {
        perror(NULL);
        return errno;
    }

    int child_size = getpagesize();
    size_t shm_size = child_size * (argc - 1);

    if (ftruncate(shm_fd, shm_size) == -1) {
        perror(NULL);
        shm_unlink(shm_name);
        return errno;
    }

    for (int i = 1; i < argc; i++) {
        pid_t child = fork();

        int *shm_ptr = mmap(0, child_size, PROT_WRITE, MAP_SHARED, shm_fd, child_size * (i - 1));
        if (shm_ptr == MAP_FAILED) {
            perror(NULL);
            shm_unlink(shm_name);
            return errno;
        }

        if (child < 0)
            return errno;
        else if (child == 0) {
            int n = atoi(argv[i]);
            // printf("%d: %d ", n, n);

            int j = 0;
            while (n != 1) {
                if (n % 2 == 0)
                    n = n / 2;
                else
                    n = 3 * n + 1;

                // printf("%d ", n);
                *(shm_ptr + j) = n;
                j++;
                // i += sizeof(int);
            }
            // printf("\n");
            return 0;
        }
    }

    for (int i = 1; i < argc; i++) {
        pid_t childf = wait(0);
        printf("Done Parent %d, Me %d\n", getpid(), childf);
    }

    // int *shm_ptr = mmap(0, shm_size, PROT_WRITE, MAP_SHARED, shm_fd, 0);

    for (int i = 0; i < argc - 1; i++) {
        int *shm_ptr = mmap(0, child_size, PROT_WRITE, MAP_SHARED, shm_fd, child_size * i);

        int n = atoi(argv[i + 1]);
        printf("%d: ", n);
        int j = 0;
        while (shm_ptr[j] != 1) {
            printf("%d ", shm_ptr[j]);
            j++;
        }
        printf("\n");
    }


    printf("Done Parent %d, Me %d\n", getppid(), getpid());
}