diff --git a/Assignment2/CMakeLists.txt b/Assignment2/CMakeLists.txt index e9c561d..87782ed 100644 --- a/Assignment2/CMakeLists.txt +++ b/Assignment2/CMakeLists.txt @@ -1,4 +1,4 @@ -cmake_minimum_required(VERSION 3.22) +cmake_minimum_required(VERSION 3.20) project(Assignment2 C) set(CMAKE_C_STANDARD 99) diff --git a/Assignment2/main.c b/Assignment2/main.c index 0ef3917..6028713 100644 --- a/Assignment2/main.c +++ b/Assignment2/main.c @@ -1,21 +1,21 @@ #include #include -#include #include #include #include #include +#include -void print_prompt() { - printf("[%d]> ", getpid()); +#define MAX_ARGS 6 // 5 arguments and a null pointer + +void print_prompt(char *prompt) { + printf("(%d) %s", getpid(), prompt); } void one_child() { - print_prompt(); - printf("Hello, I am a parent process\n"); + print_prompt("Hello, I am a parent process\n"); if (fork() == 0) { // Child process - print_prompt(); - printf("Hello, I am a child process\n"); + print_prompt("Hello, I am a child process\n"); exit(0); } else { // Parent process wait(NULL); @@ -37,8 +37,8 @@ void add_numbers() { // Add the number to the subtotal subtotal += number; - print_prompt(); - printf("The subtotal is %d\n", subtotal); + print_prompt("The subtotal is "); + printf("%d\n", subtotal); // Write the sum to the receive_from_child pipe write(receive_from_child[1], &subtotal, sizeof(int)); @@ -47,16 +47,15 @@ void add_numbers() { } else { // Parent process int total = 0; while (number != 0) { - print_prompt(); - printf("Please input a number, 0 to terminate: "); + print_prompt("Please input a number, 0 to terminate:\n"); // Read the number from the user, and convert it to an int char buffer[100]; fgets(buffer, 100, stdin); number = atoi(buffer); // Display what was entered - print_prompt(); - printf("You entered %d\n", number); + print_prompt("You entered: "); + printf("%d\n", number); // Write to child process write(send_to_child[1], &number, sizeof(int)); @@ -65,8 +64,8 @@ void add_numbers() { read(receive_from_child[0], &total, sizeof(int)); } wait(NULL); - print_prompt(); - printf("The total is %d\n", total); + print_prompt("The total is "); + printf("%d\n", total); } close(send_to_child[0]); close(send_to_child[1]); @@ -74,17 +73,94 @@ void add_numbers() { close(receive_from_child[1]); } +void free_exec(char *buffer, char **subcommand) { + free(buffer); + for (int i = 0; i < MAX_ARGS; i++) { + free(subcommand[i]); + } + free(subcommand); +} + +void exec() { + print_prompt("Please input exec subcommand:\n"); + + char *buffer = calloc(100, sizeof(char)); // input buffer size 100 + char **subcommand = calloc(6, sizeof(char *)); //size 6 to allow for 5 arguments and a null pointer + for (int i = 0; i < MAX_ARGS; i++) { + subcommand[i] = NULL; //make sure each pointer is a null pointer + } + for (int i = 0; i < MAX_ARGS; i++) { + fgets(buffer, 100, stdin); + buffer[strcspn(buffer, "\n")] = 0; // Remove trailing newline + if (strcmp(buffer, ";") == 0) { // end of command, do not add to subcommand + break; + } + char *arg = calloc(strlen(buffer), sizeof(char) + 1); //allocate memory for argument of exact size + strncpy(arg, buffer, strlen(buffer)); //copy buffer into arg + subcommand[i] = arg; //add arg to subcommand + } + + if (fork() == 0) { // Child process + execvp(subcommand[0], subcommand); + exit(0); + } else { // Parent process + wait(NULL); + free_exec(buffer, subcommand); //needs to be after wait to not use after free + } +} + +int numPlaces(int n) { + if (n < 0) n = (n == INT_MIN) ? INT_MAX : -n; + if (n < 10) return 1; + if (n < 100) return 2; + if (n < 1000) return 3; + if (n < 10000) return 4; + if (n < 100000) return 5; + if (n < 1000000) return 6; + if (n < 10000000) return 7; + if (n < 100000000) return 8; + if (n < 1000000000) return 9; + return 10; +} + +int pow2(int num) { + int ret = 2; + for (int i = 0; i < num - 1; i++) { + ret *= 2; + } + return ret; +} + +void processtree() { + print_prompt("Please input a number:\n"); + char buffer[100]; + fgets(buffer, 100, stdin); + int number = atoi(buffer); + int power = pow2(number); + int string_length = numPlaces(power); + + print_prompt("The value is 0\n"); + for (int i = 1; i < power; i++) { + if (fork() == 0) { // Child process + char num[string_length]; + sprintf(num, "The value is %d\n", i); + print_prompt(num); + exit(0); + } else { + wait(NULL); + } + } +} + int main() { - bool is_looping = true; - // Listen loop - while (is_looping) { - print_prompt(); - + while (true) { + print_prompt("Please input a shell command:\n"); char input[100]; fgets(input, 100, stdin); // Input for commands + if (strcmp(input, "stop\n") == 0) { // Stop command - is_looping = false; + break; } if (strcmp(input, "onechild\n") == 0) { // One child command one_child(); @@ -92,23 +168,11 @@ int main() { if (strcmp(input, "addnumbers\n") == 0) { // Add numbers command add_numbers(); } - if (strcmp(input, "exec\n") == 0) { - char *args[2]; - args[0] = "/bin/ls"; - args[1] = NULL; - execv(args[0], args); + if (strcmp(input, "exec\n") == 0) { // Exec command + exec(); + } + if (strcmp(input, "processtree\n") == 0) { // Process tree command + processtree(); } } -} - -void temp() { - char input[5][100]; - char buffer[500]; - //Print prompt - print_prompt(); - if (fgets(buffer, 500, stdin) == NULL) { - exit(0); - } - //split buffer on spaces into input array - sscanf(buffer, "%s %s %s %s %s", input[0], input[1], input[2], input[3], input[4]); } \ No newline at end of file