You will write a program (the controller) [the C programming language] that will synchronize the actions of other compute-intensive processes (compute processes). Signals will be used to cause this synchronization. The synchronization will be used to obtain an estimate of the elapsed time required for the compute-intensive processes to perform their computations. This measurement is to be made by the controller. This measurement cannot be started until the compute processes have initialized and have reported that they are read. The controller then tells the compute processes to compute. As each compute process completes its processing it reports back to the controller that it is done. The controller then tells the compute processes to print out their results. The exchange of messages is shown in the diagram below (for simplicity, only one instance of each command is depicted). The link to the diagram is provided below.

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Additional requirements are detailed below:

1. Number of compute processes (MAXCP): The value of MAXCP must be specified via a #define statement.

2. header file: Write and use a header (.h) file. Include in this header file your #define statements and other appropriate items. The program should be tested with MAXCP set to 3.

3. Makefile: Write a makefile to control the compilation of your programs.

4. Use of Signals: the ready and done commands are to be indicated by SIGUSR2 signals sent by each compute process to the controller. The compute and print commands are indicated by SIGUSR1 signals sent by the controller to each compute process.

5. Controller: the controller is to produce MAXCP child processes; these will exec the compute program (described below). The controller must control the execution of the computation as described above and in the figure. It must measure the length of the time interval of the computation (T). Note that the interval starts right before the first compute command is issued and ends with the receipt of the last done command.

6. Compute Processes: The compute program must participate in the exchange of signals as described above and in the figure. The computation to be performed is as follows:

Each process will receive an id value such as 0, 1 or 2.

For integer c in the interval [id*INC, (id+1)*INC) it is to determine the maximum number of times that the following relation is true: (c² = a² + b²) where a and b are integers in the interval (0, c). INC should initially be set to 1000; however, it can be made larger in increments of 1000 if the computation time (T) is smaller than 60 seconds.

7. Messages: Output messages must clearly show the following items:

Sending and receiving of SIGUSR1 and SIGUSR2 signals; the messages must indicate which process is sending or receiving these signals.

Measured elapsed time of the computation interval.

Exit status of the compute processes.

Termination of the controller.

Values of the computed counts and related interval to which it is applicable. Other items should be added to this list in order to clearly demonstrate the processes are working correctly.

Partial sample output for MAXCP = 2 appears below; measured elapsed time not shown:

compute(152): Sending SIGUSR2 to parent process.

compute(153): Sending SIGUSR2 to parent process.

controller: SIGUSR2 received.

controller: SIGUSR2 received.

controller: Sending SIGUSR1 to child process (152).

controller: Sending SIGUSR1 to child process (153).

compute(152): SIGUSR1 received.

compute(153): SIGUSR1 received.

compute(152): For interval [0,100000): count = nnnn

compute(153): For interval [100000,200000): count = mmmm

compute(152): Terminating normally.

controller: child (152) terminated with exit status: 0

compute(153): Terminating normally.

controller: child (153) terminated with exit status: 0

controller: Complete.

Hints:

See the man pages for: sigaction and pause.

For the redirected output in order to get the messages from the controller and compute processes to appear in the order that the messages were issued, it may be necessary to precede each message with a timestamp and sort the messages based on the timestamp.