Homework #6 Due:Friday, December 5, 1997, at 11:59PM Points: 100 The C Programming Language Submitting: Put your program into files named as indicated and submit them as described in the All About Homework handout. Remember, wešll compile and run them on the DECs, so be sure they work there! (Note: if you use other file names, we will deduct 5 points.) Write a program that determines whether a user can access a file to perform the specified operation. The operation(s) are indicated by command-line options, and are: r read w write x execute For example, if your executable is named access, then access r bishop /etc/motd should print bishop can read /etc/motd Options may be combined; for example: access rwx bishop /etc/motd should print bishop can read /etc/motd bishop can write /etc/motd bishop cannot execute /etc/motd Only one user and one file may be named per command. If the user is given as an integer, assume that is a UID. For example: access -rw 917 /etc/passwd should print User 917 can read /etc/passwd User 917 cannot write /etc/passwd If the useršs UID is 0, print the message That user is the superuser! and exit. If the object named as a file is a symbolic link, give the results that correspond to the target of the symbolic link (in other words, follow them). Hints: Use stat(2). The program user.c discussed in class (see the lecture notes for Lecture #9) gives an example of translating from names to UIDs and how to handle groups. The program finfo.c in ~cs40/samples shows you how to access the directory modes. Also, use getopt(3) for handling the options; it makes that part quite simple. The program prs.c (see the notes for lecture #8) gives an example of that also. Homework #6 ECS 40 FALL 1997 Page 1