I have an assignment that require me to setting a shared memory for parent and child to communicate. When the child is fork(), I will have to report the create time and send to the parent. After the child finish exec(), i will send another time to the parent where parent will take the time differences and report it to a .txt. All of this will be done in C language.

Homework #1, Processes 1) (20 points) Write a C program (time_shm.c and time_pipe.c) that determines the amount of time necessary to run a command from the command line. This program will be run as ./time and will report the amount of elapsed time to run the specified command. This will involve using fork) and execvp ) functions, as well as the gettimeofday ) function to determine the elapsed time. It will also require the use of two different IPC mechanisms The general strategy is to fork a child process that will execute the specified command. However, before the child executes the command, it will record a timestamp of the current time (which we term "starting time"). The parent process will wait for the child process to terminate. Once the child terminates, the parent will record the current timestamp for the ending time. The difference between the starting and ending times represents the elapsed time to execute the command. The example output below reports the amount of time to run the command 1s: ./time ls -1 total 156 -rwxr-xr-x 1 thomas users 25616 Feb 4 15:59 a.out -rw-r--r--1 thomas users 252 Feb 4 16:00 output.txt -rwxr-xr-x 1 thomas users 86024 Feb 2 20:58 project.exe -rwxr-xr-x 1 thomas users 25616 Feb 2 21:00 time -rw-r--r-- 1 thomas users 5144 Feb 2 20:58 time.c Elapsed time: 0.001448 seconds As the parent and child are separate processes, they will need to arrange how the starting time will be shared between them. You will write two versions of this program, each representing a different method of IPC. 2a) (10 points) The first version, time shm.c, will have the child process write the starting time to a region of shared memory before it calls execvp (). After the child process terminates, the parent will read the process is forked, allowing both the parent and child processes access to the region of shared memory 2b) (10 points) The second, time_pipe.c, version will use a pipe. The child will write the starting time to the starting time from shared memory. The region of shared memory should be established before the child pipe, and the parent will read from it following the termination of the child process. You will use the gettimeofday () function to record the current timestamp. This function is passed a pointer to a struct timeval object, which contains two members: tv_sec and tv_usec. These represent the number of elapsed seconds and microseconds since January 1, 1970 (known as the UNIX EPOCH). The following code sample illustrates how this function can be used Homework #1, Processes 1) (20 points) Write a C program (time_shm.c and time_pipe.c) that determines the amount of time necessary to run a command from the command line. This program will be run as ./time and will report the amount of elapsed time to run the specified command. This will involve using fork) and execvp ) functions, as well as the gettimeofday ) function to determine the elapsed time. It will also require the use of two different IPC mechanisms The general strategy is to fork a child process that will execute the specified command. However, before the child executes the command, it will record a timestamp of the current time (which we term "starting time"). The parent process will wait for the child process to terminate. Once the child terminates, the parent will record the current timestamp for the ending time. The difference between the starting and ending times represents the elapsed time to execute the command. The example output below reports the amount of time to run the command 1s: ./time ls -1 total 156 -rwxr-xr-x 1 thomas users 25616 Feb 4 15:59 a.out -rw-r--r--1 thomas users 252 Feb 4 16:00 output.txt -rwxr-xr-x 1 thomas users 86024 Feb 2 20:58 project.exe -rwxr-xr-x 1 thomas users 25616 Feb 2 21:00 time -rw-r--r-- 1 thomas users 5144 Feb 2 20:58 time.c Elapsed time: 0.001448 seconds As the parent and child are separate processes, they will need to arrange how the starting time will be shared between them. You will write two versions of this program, each representing a different method of IPC. 2a) (10 points) The first version, time shm.c, will have the child process write the starting time to a region of shared memory before it calls execvp (). After the child process terminates, the parent will read the process is forked, allowing both the parent and child processes access to the region of shared memory 2b) (10 points) The second, time_pipe.c, version will use a pipe. The child will write the starting time to the starting time from shared memory. The region of shared memory should be established before the child pipe, and the parent will read from it following the termination of the child process. You will use the gettimeofday () function to record the current timestamp. This function is passed a pointer to a struct timeval object, which contains two members: tv_sec and tv_usec. These represent the number of elapsed seconds and microseconds since January 1, 1970 (known as the UNIX EPOCH). The following code sample illustrates how this function can be used