Exercise 1

Write opentrace.d and opentrace.stp scripts which are tracing open() system calls. They should print following information in one line:

• Call context: name of executable file, process ID, user and group IDs of user and group which are executing process.
• Path to file which should be opened.
• A string containing open() flags O_RDONLY, O_WRONLY, O_RDWR, O_APPEND, O_CREAT
• Return value of system call

For example:

tee[939(0:0)] open("/tmp/test", O_WRONLY|O_APPEND|O_CREAT) = 3

Bit flags values are presented in following table:

Flag	Solaris	Linux (x86)
O_RDONLY	bits 0-1 are not set
O_WRONLY	1	1
O_RDWR	2	2
O_APPEND	8	1024
O_CREAT	256	64

Test script that your created by experimenting with redirection to file or a pipe with tee tool:

# cat /etc/inittab > /tmp/test
# cat /etc/inittab >> /tmp/test
# cat /etc/inittab | tee /tmp/test
# cat /etc/inittab | tee -a /tmp/test

Warning

Optional: Modify your scripts so only files that have "/etc" in their path will be shown.