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  /*!
   * The purpose of this application, combined with the tool: "syscalls_and_locks_tool", is to check the correctness of the
   * lock acquisition algorithm enhancement, which designed to be clone-proof for probe mode
   *
   * This application verifies that a deadlock won't be encountered when the application calls to clone directly/indirectly,
   * while a different thread (in a different/same process) holds the lock (PIN_LOCK/PIN_RWMUTEX/client lock).
   */
  
  #include <stdio.h>
  #include <pthread.h>
  #include <stdlib.h>
  #include <unistd.h>
  #include <errno.h>
  #include <signal.h>
  
  #define TIMEOUT 120
  
  #define STACK_SIZE (1024 * 1024)    /* Stack size for cloned child */
  #include <sys/syscall.h>
  
  volatile bool thread1Init = false;
  
  int syscall_type;
  
  enum ExitType {
      RES_SUCCESS = 0,       // 1
      RES_ALARM_TIMEOUT,     // 2
      RES_MALLOC_FAILED,     // 3
      RES_RES_INVALID_ARGS   // 4
  };
  
  // Pin doesn't kill the process if the application encounters a deadlock, exit on SIGALRM.
  void ExitOnAlarm(int sig)
  {
      fprintf(stderr, "Timeout has passed, stuck in the system function library call, exit on SIGALRM\n");
      exit(RES_ALARM_TIMEOUT); 
  }
  
  // The tool puts an analysis routine on this function to notify t1
  // when the lock has been acquired.
  extern "C" void WaitThread2AcquireLock()
  {
      // do nothing
  }
   
  // The tool sets an analysis function here to notify t1 when t2
  // has acquired and released the lock.
  extern "C" void WaitUntilLockAcquiredAndReleased()
  {
      // Do nothing
  }
  
  // When the child process is created with clone(), it executes this function.
  int childFunc(void * arg)
  {
      // Do nothing
      return 0;
  }
  
  void * thread_func1(void *arg)
  {
      // Notify t2 that the lock should be acquired.
      thread1Init = true;
  
      // The tool puts an analysis routine on this function to notify t1
      // when the lock has been acquired.
      WaitThread2AcquireLock();
  
      // If syscall_type equals 1, the system function will be called
      // During this function call, the clone system call is called. We want to verify that
      // a deadlock won't be encountered while the lock is by t2.
      if(syscall_type == 1)
      {
          system("/bin/ls");
      }
  
      // If syscall_type equals 2 the popen function will be called. This function opens a process by creating a pipe,
      // forking and invoking a the shell. We want to verify that a deadlock won't be encounter when this function is being
      // called while the lock is held by t2.
      else if(syscall_type == 2)
      {
          FILE* pipe = popen("uname -r", "r");
          pclose(pipe);
      }
  
      // If syscall_type equals 3, the new thread will be created in a new thread group.
      // If syscall_type equals 4, the new thread will be in the same thread group as the caller and will share its
      // virtual memory.
      // We want to verify, in both of these scenarios, that a deadlock won't be encountered when the clone system call
      // is being called while the lock is held  by t2.
      else if (syscall_type == 3 || syscall_type == 4)
      {
          char *stack;
          char *stackTop;
          stack = (char *)malloc(STACK_SIZE);
          if (stack == NULL) exit(RES_MALLOC_FAILED);
          stackTop = stack + STACK_SIZE;
  
          if (3 == syscall_type)
          {
              clone(childFunc, stackTop, 0 , 0);
          }
          else if (4 == syscall_type)
          {
              clone(childFunc, stackTop, CLONE_VM | CLONE_SIGHAND | CLONE_THREAD, 0);
          }
  
          // Sleep for 30 seconds to increase the probability that the new process which has been created by clone
          // will finish its execution.
          sleep(30);
      }
  
      return 0;
  }
  
  void * thread_func2 (void *arg)
  {
      // Wait until t1 starts to run.
      while(!thread1Init) sched_yield();
  
      // Wait until the lock is acquired and released.
      WaitUntilLockAcquiredAndReleased();
  
      return 0;
  }
   
  //  Expected argv arguments:
  //  [1] syscall type
  //    1 - execute the system function.
  //    2 - execute the popen function.
  //    3 - execute the clone system call where the parent of the new child will be different
  //        from that of the calling process.
  //    4 - execute the clone system call where the parent of the new child will be the same as
  //        that of the calling process.
  int main (int argc, char *argv[])
  {
      if(argc!=2)
      {
           fflush(stderr); 
           exit(RES_RES_INVALID_ARGS);
      }
  
      syscall_type = atoi(argv[1]);
  
      pthread_t t1;
      pthread_t t2;
  
      pthread_create (&t1, 0, thread_func1, 0);
      pthread_create (&t2, 0, thread_func2, 0);
  	
      //Exit in 120 sec 
      signal(SIGALRM, ExitOnAlarm);
      alarm(TIMEOUT);
  	
      pthread_join (t1, 0);
      pthread_join (t2, 0);
  
      printf("All threads exited. The test PASSED\n");
      return RES_SUCCESS;
  }
   
  