Linux API

Dr. Michael L. Collardwww.sdml.info/collard

www.sdml.info/collard/linuxcollard@cs.kent.edu

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Linux Systems Programming

• Linux API – set of calls that applications, directly or indirectly, use to interact with the Linux kernel

• File, directory, and filesystem access• Communication• Concurrency• Control

Device Interface

• files, terminals, disks, tapes, audio, network, peripheral devices

• device driver – Kernel module, typically LKM (Loadable Kernel Module)

• devices represented as special files

Device Types

• Regular file• Block device (block special file)– similar to a disk, transfers information in blocks

• Character device (character special file)– terminal-like with a stream of bytes in order

• Network device– no device node, use name with socket to ioctl

• File-system device– Rarely directly access, through ioctl

Uniform Device Access

• File descriptor 0 – STDIN_FILENO, 1 – STDOUT_FILENO, 2 – STDERR_FILENO

• open• close• read• write• ioctl

Process Creation

• init – special process, parent of all processes

• fork• exec family: execle• wait

Interrupts & Signals

• Interrupt generated by hardware, typically by external device drivers, and typically asynchronous

• Signal How software is notified of an asynchronous event

• Signal Handler – How a process catches and handles a generated signal

Terminal Control

• Special Devices have special capabilities• termios.h• tcgetattr• tcsetattr