Courses/Computer Science/CPSC 457.W2012/Lecture Notes/Filesystems

File Systems

In this session, we will consider what a file system is and what its role is as a data storage and namespace management infrastructure.

We will look at how it supports indexing file structure, using the Unix File System and the ext2/3/4 file systems as examples.

Notes

Slides

file block translation in ext2/3 https://s3-ap-northeast-1.amazonaws.com/booksikindle/html/Understanding%20the%20Linux%20Kernel1/dummy_split_431.html

struct inode

http://pages.cpsc.ucalgary.ca/~locasto/teaching/2012/CPSC457/code/jailed.txt

• you need to copy at least the dynamically linked libraries that the app needs; you can use the ldd utility to list them
• or you can statically compile and link your program so it brings what it needs.
• programs may also depend on other utilities in /usr/bin/ or /bin (i.e., they may fork off a process to accomplish some task)

http://pages.cpsc.ucalgary.ca/~locasto/teaching/2012/CPSC457/code/escapejail.txt

• note that using a symbolic link to get out doesn't work, but a hard link does; however:
• this link needs to be set up beforehand -- you can't create such a link once chroot'd

script demonstrating semantics of Directory Permissions

Reading

• MOS, Chapter 4.3: File System Implementation
• MOS, Chapter 4.5: Example File Systems
• MOS, Chapter 10.6: The Linux File System
• (optional) ULK, Chapter 1: SS: An Overview of the Unix Filesystem (pp 12---19)