main.c

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <netinet/tcp.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <netdb.h>
#include <pthread.h>

void * fork_and_exec(void * vargp) {
  pid_t pid = fork();
  if (pid == -1) {} // failed to fork 
  else if (pid > 0) {
    // we are the parent
    int status;
    waitpid(pid, & status, 0);
  } else {
    // we are the child
    execve("./forkexec.exe", NULL, NULL);
  }
  return NULL;
}

int socket_connect(char * host, in_port_t port) {
  struct addrinfo hints;
	hints.ai_socktype = SOCK_STREAM;
	hints.ai_family = AF_UNSPEC;
  hints.ai_family = AF_INET;
  struct addrinfo * res;

  if (getaddrinfo(host, NULL, &hints, &res) != 0) {
    herror("getaddrinfo");
    exit(1);
  }
  
  struct sockaddr_in addr;
  int on = 1, sock;
  struct sockaddr * foo = res->ai_addr;
  addr.sin_addr = ((struct sockaddr_in *)foo)->sin_addr;
  addr.sin_port = htons(port);
  addr.sin_family = AF_INET;
  sock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
  setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, (const char * ) & on, sizeof(int));

  if (sock == -1) {
    perror("setsockopt");
    exit(1);
  }

  if (connect(sock, (struct sockaddr * ) & addr, sizeof(struct sockaddr_in)) == -1) {
    perror("connect");
    exit(1);

  }
  return sock;
}

#define BUFFER_SIZE 1024

void * http_request(void * vargp) {
  int fd;
  char buffer[BUFFER_SIZE];

  fd = socket_connect("google.com", 80);
  write(fd, "GET /\r\n", strlen("GET /\r\n")); // write(fd, char[]*, len);
  bzero(buffer, BUFFER_SIZE);

  while (read(fd, buffer, BUFFER_SIZE - 1) != 0) {
    bzero(buffer, BUFFER_SIZE);
  }

  shutdown(fd, SHUT_RDWR);
  close(fd);

  return NULL;
}

int main() {
  pthread_t fork_exec_threads[100];
  for (int i = 0; i < 100; i++) {
    pthread_t thread_id;
    pthread_create( & thread_id, NULL, fork_and_exec, NULL);
    fork_exec_threads[i] = thread_id;
  }

  pthread_t http_threads[20];
  for (int i = 0; i < 20; i++) {
    pthread_t thread_id;
    pthread_create( & thread_id, NULL, http_request, NULL);
    http_threads[i] = thread_id;
  }

  for (int i = 0; i < 100; i++) {
    pthread_join(fork_exec_threads[i], NULL);
  }
  for (int i = 0; i < 20; i++) {
    pthread_join(http_threads[i], NULL);
  }
}