Description:

This is a repository for my system programming class project (2022).

mon_watch is a C program that mimics the behavior of the watch command in UNIX systems. It executes a specified command repeatedly until interrupted by the user. The interval between executions and the command itself are provided as command-line arguments.

Features:

• Utilizes POSIX signals for handling interruptions and timing.
• Forks a child process to execute the specified command.
• Monitors the child process and kills it if it exceeds the specified time interval or if interrupted by the user.
• Handles failures gracefully, providing meaningful error messages and appropriate exit codes.
• Prevents the program from hanging or entering into a busy wait loop.

Usage:

./mon_watch INTERVAL COMMAND [ARG]

• INTERVAL: The time interval in seconds between each execution of the command.
• COMMAND [ARG]: The command to be executed along with its arguments.

Exit Codes:

• 0: Success (terminated by SIGINT).
• 1: System call failure in the main program.
• 2: Incorrect arguments provided.
• 4: Unable to execute the specified command.
• 8: Child process failed repeatedly.

Compilation:

cc -Wall -Wextra -Werror mon_watch.c -o mon_watch

Run:

./mon_watch INTERVAL COMMAND [ARG]

Testing:

To run the provided tests:

make test