chiragragarwal / exec Goto Github PK

Author	: Chirag R. Agarwal
ID		: [email protected]
Problem	: Experiencing execv() commands in Linux
Site	: http://agarwalchirag.wordpress.com

FILES IN MY FOLDER :

1) q1_main.c :
	It is the main driver file. It further forks all other processes.
	
2) function.c :
	It is the implementation file. It is the heart of the code.
	
3) HEADER.h :
	It is the header file that contains all the variable and function declarations.

4) input.txt :
	The input file. The input format is as follows (words are '\t' separated) :
	
	7
	ls	-	/bin	-l -a -x
	ps	ls	/bin	-e ax 
	echo	-	-	hello
	pwd	echo	/bin	NULL
	who	pwd	-	-d
	cat	ls	-	floyd.txt
	ifconfig ls 	/sbin	NULL
	
	The first line contains the total number of commands to be executed followed by the commands and dependencies as mentioned in the question.
	
	
5) floyd.txt :
	Just an arbitrary text file that contains some text. It is used to demonstrate the 'CAT' operation.
	
6) Makefile :
	The Makefile.

7) Q1_README :
	What you are reading presently.
	
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HOW TO EXECUTE MY PROGRAM ?

Simply in the outer folder, type 'make'
This will compile the process and create and executable named 'exe'

Now type './exe input.txt' to execute the program.

If you do not enter the argument, an appropriate error message is displayed on the terminal before exiting.
All the commands are excuted and the output is displayed on the terminal. 
I've added an extra line before executing each command to help distinguish between them.

To clean all the extra files created by the program type "make clean" on the terminal.

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STRUCTURE :

I've read the input.txt file line by line and stored them in separate arrays arrA and arrB as expected in the question.
The main process forks two child processes A and B and excutes the commands in the arrays arrA and arrB respectively and concurrently.
The processes A and B fork a child everytime a new command is encountered. The next command in that array is executed when this current process successfully terminates.