TestOpen failing after creating 32770 sockets

[dormail]

Hi, when running kens-part1, I run into the problem of the program crashing after 32770 sockets. When changing the beginning of the test to something like this

    const static int test_size = 128;
    const static int test_repeat = 128;

It has no problem completing the test. I first though the problem might lay in my implementation of some file descriptor stuff but it is all deep inside the KENS source code which we are not supposed to change right (like functions we can not overwrite, files we are not supposed to hand in)
Or did I simply not understand the assignment correctly?

[Pusnow]

KENSv3/app/kens/testopen.cpp

Lines 36 to 55 in 0226d32

	for (int j = 0; j < test_repeat; j++) {
	int fd_array[test_size];
	for (int k = 0; k < test_size; k++) {
	fd_array[k] = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
	if (fd_array[k] < 0)
	failed++;
	else
	success++;
	}
	for (int k = 0; k < test_size; k++) {
	for (int i = k + 1; i < test_size; i++) {
	if (fd_array[k] == fd_array[i])
	duplicated++;
	}
	}
	for (int k = 0; k < test_size; k++) {
	close(fd_array[k]);
	}
	}

You might have to implement close() system call (line 53).
Also, you should use file descriptor helper functions: https://github.com/ANLAB-KAIST/KENSv3/wiki/Tip:-Managing-File-Descriptors .

[dormail]

Yes, I implemented a close() call which also utilized the File Descriptor methods from KENS, the problem still persists. What I found is, that evonthough the sockets get closed, the counter for the file desriptor keeps rizing (thats how I got the exact number) so I am not sure if the deletion is working as intended.

[Pusnow]

This is how to use the file descriptor method:

  int fd[6];
  fd[0] = createFileDescriptor(pid); // returns 3
  fd[1] = createFileDescriptor(pid); // returns 4
  fd[2] = createFileDescriptor(pid); // returns 5
  fd[3] = createFileDescriptor(pid); // returns 6
  fd[4] = createFileDescriptor(pid); // returns 7
  printf("fd: %d %d %d %d %d\n", fd[0], fd[1], fd[2], fd[3], fd[4]);

  removeFileDescriptor(pid, fd[2]); // remove fd(5)

  fd[5] = createFileDescriptor(pid); // returns 5
  printf("fd[5]: %d\n", fd[5]);


  removeFileDescriptor(pid, fd[0]); // remove fd(3)
  removeFileDescriptor(pid, fd[1]); // remove fd(4)
  removeFileDescriptor(pid, fd[3]); // remove fd(6)
  removeFileDescriptor(pid, fd[4]); // remove fd(7)
  removeFileDescriptor(pid, fd[5]); // remove fd(5)


  fd[0] = createFileDescriptor(pid); // returns 3
  fd[1] = createFileDescriptor(pid); // returns 4
  fd[2] = createFileDescriptor(pid); // returns 5
  fd[3] = createFileDescriptor(pid); // returns 6
  fd[4] = createFileDescriptor(pid); // returns 7
  printf("fd: %d %d %d %d %d\n", fd[0], fd[1], fd[2], fd[3], fd[4]);

Output:

fd: 3 4 5 6 7
fd[5]: 5
fd: 3 4 5 6 7

As you can see, if you use the methods properly, file descriptor would not keep rising.

[dormail]

Hi, thank you I now understood what I did wrong, thank you for your help!