Homework 2

Due Date: January 28, 2002	100 Points

1.	(15 points) Chapter 19, exercise 4

2.	(15 points) Chapter 19, exercise 6

3.	(70 points) Read the manual page for popen(3). However, your version will differ from the system version in the 
following ways:

a.	All environment variables should be deleted, except for PATH, IFS, TZ, and SHELL. These shold be set as 
follows: PATH to "/bin:/usr/bin:/usr/local/bin:/pkg/bin"; IFS to "\t\n "; TZ to "PST8PDT"; and SHELL to 
the user's login shell.

b.	All file descriptors except 0, 1, and 2 should be closed.

c.	The umask should be set to 077.

	Please turn in a tar file containing a source file popen.c with the source of popen and a README file. We will 
untar it, copy a Makefile, a test program, and a driver into the directory, and compile and test your routine. Your 
routine must be in the single file popen.c.