Servers

In this section, you will implement several different servers. With the conditional compilation preprocessor directives (i.e. the #ifdef directives), we only need to change how we call the request handler in each of these different servers.

Fork server

Implement forkserver. You won’t be writing much new code.

• The child process should call request_handler with the client socket fd. After serving a response, the child process will terminate.
• The parent process will continue listening and accepting incoming connections. It will not wait for the child.
• Remember to close sockets appropriately in both the parent and child process.

Thread server

Implement threadserver.

• Create a new pthread to send the proper response to the client.
• The original thread continues listening and accepting incoming connections. It will not join with the new thread.

Pool server

Implement poolserver.

• Your thread pool should be able to concurrently serve exactly --num-threads clients and no more. Note that we typically use --num-threads + 1 threads in our program. The original thread is responsible for accepting client connections in a while loop and dispatching the associated requests to be handled by the threads in the thread pool.
• Begin by looking at the functions in wq.h.
  • The original thread (i.e. the thread you started the httpserver program with) should wq_push the client socket file descriptors received from accept into the wq_t work_queue declared at the top of httpserver.c and defined in wq.h.
  • Then, threads in the thread pool should use wq_pop to get the next client socket file descriptor to handle.
• You’ll need to make your server spawn --num-threads new threads which will spin in a loop doing the following:
  • Make blocking calls to wq_pop for the next client socket file descriptor.
  • After successfully popping a to-be-served client socket fd, call the appropriate request handler to handle the client request.