p3-test.c

#ifdef CS333_P3
// A starting point for writing your own p3 test program(s).
// Notes
// 1. The parent never gets to the wait() call, so killing any child will cause that
//    child to move to zombie indefinitely.
// 2. When running as a background process, the parent of the main process
//    will be init. This is how background processes work. Read sh.c for details.
// 3. Useful test: run in background then kill a child. Child will be in zombie. Now
//    kill parent. Should get "zombie!" equal to the number of zombies.
//    ps or ^p should now show init as the parent of all child processes.
//    init will then reap the zombies.
// 4. Can also be used to show that the RUNNABLE list is still round robin.

#include "types.h"
#include "user.h"
#include "param.h"
#include "pdx.h"

int
main(int argc, char *argv[])
{
  int rc, i = 0, childCount = 20;

  if (argc > 1) {
    childCount = atoi(argv[1]);
  }
  if (!childCount) {
    printf(1, "No children to create, so %s is exiting.\n", argv[0]);
    exit();
  }

  printf(1, "Starting %d child processes that will run forever\n", childCount);

  do {
    rc = fork();
    if (rc < 0) {
      printf(2, "Fork failed!\n");
      exit();
    }
    if (rc == 0) { // child process
      while(1) i++;  // infinite
      exit();  // not reachable.
    }
    childCount--;
  } while(childCount);

  printf(1, "All child processes created\n");
  while(1) i++;  // loop forever and don't call wait. Good for zombie check
  exit();  // not reachable
}
#endif // CS333_P3