4003-440-02 Operating Systems I Module 6. Process Programming -- Lecture Notes Prof. Alan Kaminsky -- Winter Quarter 2012 Rochester Institute of Technology -- Department of Computer Science The Unix Process API The man command System calls and library routines (Linux) fork execve, execl wait errno, strerror Program forkdemo1 -- source code Demonstrates fork and wait Program forkdemo2 -- source code Demonstrates fork, execl, and wait Interprocess Communication/Synchronization With Pipes File descriptors File descriptor 0 = standard input File descriptor 1 = standard output File descriptor 2 = standard error System calls and library routines (Linux) pipe, fopen read, fscanf write, fprintf close, fclose dup Program pipedemo1 -- source code Demonstrates pipe and fork Program pipedemo2 -- source code Demonstrates pipe, fork, dup, and exec Interprocess Synchronization With Semaphores System calls and library routines (Linux) ipc -- Summary of IPC semget -- Get or create semaphores semop -- Acquire or release semaphores semctl -- Initialize, remove, and do other things to semaphores Other system calls and library routines (Linux) signal -- Catch a signal kill -- Send a signal to a process Helpful commands (Linux) ipcs -- Print status of IPC resources ipcrm -- Remove IPC resources kill -- Kill a process Program dp1 -- source code Program philosopher1 -- source code Demonstrates semaphores, signal, and kill Interprocess Communication With Shared Memory System calls and library routines (Linux) ipc -- Summary of IPC shmget -- Get or create shared memory segments shmat, shmdt -- Attach or detach shared memory segments shmctl -- Do various things to shared memory segments, such as remove them Program pc1 -- source code Program consumer1 -- source code Program producer1 -- source code struct circbuf -- header file -- source code Demonstrates shared memory, semaphores, signal, and kill If you're going to do stuff with shared memory, it's easier to have multiple threads in one process Interprocess Communication With Messages System calls and library routines (Linux) ipc -- Summary of IPC msgget -- Get or create message queues msgsnd, msgrcv -- Send or receive messages msgctl -- Do various things to message queues, such as remove them Demo programs TBD If you're going to do stuff with interprocess messages, it's more flexible to use networking (TCP sockets, UDP datagrams) Operating Systems I • 4003-440-02 • Winter Quarter 2012 Course Page Alan Kaminsky • Department of Computer Science • Rochester Institute of Technology • 4486 + 2220 = 6706 Home Page Copyright © 2013 Alan Kaminsky. All rights reserved. Last updated 12-Jan-2013. Please send comments to ark­@­cs.rit.edu.