báo cáo bài tập nhập môn hệ điều hành lab 7 2

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<b>TRƯỜNG ĐẠI HỌC TÔN ĐỨC THẮNG KHOA CÔNG NGHỆ THÔNG TIN </b>

<b>BÁO CÁO BÀI TẬP NMHĐH HK2, 2022-2023</b>

<b>Lab 7</b>

<b>Nhóm:</b> 10 <b>Tổ:</b> 01

1: Trần Ngọc Hải My ( MSSV: 52300128)

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<b>B. PHẦN BÀI TẬP</b>

<b>BÀI 1: </b>

The child process passes the first argument n from argv [1], which is an integer greater than 3,to its parent process through the Message Queue. The parent process receive, calculates thesum of factorial of numbers from 1 to n and writes it to the Message Queue. Child processesreceive and output data to the screen.

<b>A: Code Chương Trình:</b>

#include <stdio.h>#include <stdlib.h>#include <sys/types.h>#include <sys/ipc.h>#include <sys/msg.h>#include <unistd.h>

#define MAX_SIZE 256

struct message { long mtype; int data; };

int factorial(int num) { if (num == 0 || num == 1) return 1;

else

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return num * factorial(num - 1);}

int main(int argc, char *argv[]) { if (argc < 2) {

fprintf(stderr, "Usage: %s <n> (where n > 3)\n", argv[0]); return EXIT_FAILURE;

}

int n = atoi(argv[1]); if (n <= 3) {

fprintf(stderr, "n must be greater than 3\n"); return EXIT_FAILURE;

}

key_t key = ftok(".", 'm'); if (key == -1) { perror("ftok"); return EXIT_FAILURE; }

int msgid = msgget(key, 0666 | IPC_CREAT); if (msgid == -1) {

perror("msgget"); return EXIT_FAILURE;

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}

pid_t pid = fork(); if (pid == -1) { perror("fork"); return EXIT_FAILURE; }

if (pid == 0) {

struct message msg_to_send; msg_to_send.mtype = 1; msg_to_send.data = n;

if (msgsnd(msgid, &msg_to_send, sizeof(int), 0) == -1) { perror("msgsnd");

return EXIT_FAILURE; }

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int received_n = msg_received.data; int sum_of_factorials = 0;

for (int i = 1; i <= received_n; i++) { sum_of_factorials += factorial(i); }

struct message msg_to_send; msg_to_send.mtype = 1;

msg_to_send.data = sum_of_factorials;

if (msgsnd(msgid, &msg_to_send, sizeof(int), 0) == -1) { perror("msgsnd");

return EXIT_FAILURE; }

}

if (pid == 0) {

struct message msg_received;

if (msgrcv(msgid, &msg_received, sizeof(int), 1, 0) == -1) { perror("msgrcv");

return EXIT_FAILURE; }

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printf("Sum of factorials from 1 to %d is: %d\n", n, msg_received.data); }

if (pid != 0) {

if (msgctl(msgid, IPC_RMID, NULL) == -1) { perror("msgctl");

return EXIT_FAILURE; }

}

return EXIT_SUCCESS;}

<b>B: Kết Quả Demo:</b>

<b>BÀI 2: </b>

The child process reads data from a file consisting of two integers and an operation +, -, *, /and passes all to the parent process (by a Message Queue). The parent process calculates theresult and returns it to the child process. The child process writes the result to the file.

<b>A: Code Chương Trình:</b>

#include <stdio.h>#include <stdlib.h>#include <sys/types.h>

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#include <sys/ipc.h>#include <sys/msg.h>#include <unistd.h>#include <sys/wait.h>

struct message { long mtype; int num1; int num2; char op; };

void child_process(char *input_filename, char *output_filename) { FILE *input_file = fopen(input_filename, "r");

if (input_file == NULL) { perror("Error opening input file"); exit(EXIT_FAILURE); }

int num1, num2; char op;

if (fscanf(input_file, "%d %d %c", &num1, &num2, &op) != 3) { perror("Error reading input file");

fclose(input_file); exit(EXIT_FAILURE);

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if (msgsnd(msgqid, &msg, sizeof(struct message) - sizeof(long), 0) == -1) { perror("Error sending message to parent process");

exit(EXIT_FAILURE); }

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if (msgrcv(msgqid, &msg, sizeof(struct message) - sizeof(long), 2, 0) == -1) { perror("Error receiving message from parent process");

exit(EXIT_FAILURE); }

FILE *output_file = fopen(output_filename, "w"); if (output_file == NULL) {

perror("Error opening output file"); exit(EXIT_FAILURE);

}

fprintf(output_file, "%d\n", msg.num1); fclose(output_file);

if (msgctl(msgqid, IPC_RMID, NULL) == -1) { perror("Error removing message queue"); exit(EXIT_FAILURE);

}}

void parent_process() { key_t key = ftok(".", 'm'); if (key == -1) {

perror("Error generating key for message queue");

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exit(EXIT_FAILURE); }

int msgqid = msgget(key, 0666 | IPC_CREAT); if (msgqid == -1) {

perror("Error creating message queue"); exit(EXIT_FAILURE);

int result; switch (msg.op) { case '+':

result = msg.num1 + msg.num2; break;

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break; case '/':

if (msg.num2 == 0) {

perror("Error: Division by zero"); exit(EXIT_FAILURE); }

result = msg.num1 / msg.num2; break;

default:

perror("Error: Invalid operation"); exit(EXIT_FAILURE); }

msg.mtype = 2; msg.num1 = result;

if (msgsnd(msgqid, &msg, sizeof(struct message) - sizeof(long), 0) == -1) { perror("Error sending result message to child process");

exit(EXIT_FAILURE); }

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exit(EXIT_FAILURE); }

pid_t pid = fork();

if (pid < 0) {

perror("Fork failed"); exit(EXIT_FAILURE); } else if (pid == 0) {

child_process(argv[1], argv[2]); exit(EXIT_SUCCESS); } else {

parent_process();

int status; wait(&status);

exit(EXIT_SUCCESS); }

return 0;}

<b>B: Kết Quả Demo:</b>

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