Linux Multi-user and multi-user boundaries

1. Requirements background

2. Multi-user boundaries: A separate working directory

3. Multi-user boundaries: actionable/accessible Resources

4. Multi-user boundaries: actionable actions

5. Multi-user Feature ID: UID and GID

--------------------------------------------------------

Http://www.jikexueyuan.com/course/25_2.html?ss=1

--------------------------------------------------------

1. Requirements background

Lack of resources: machines are too expensive, so only a single machine can be used by multiple users, but users cannot interact with each other

Central Unified Management: Have Super Administrator privileges or ordinary user rights, permissions control

2. Multi-user boundaries: A separate working directory

Each user has their own home directory, each user has their own desktop/document directory

3. Multi-user boundaries: actionable/accessible Resources

4. Multi-user boundaries: actionable actions

Different users can manipulate and access resources must be different

File resources, Hardware device resources

Resource classification: Restrict certain files to only some users

Rights Management: Read and Write, execute

5. Multi-user Feature ID: UID and GID

Name is just for reading.

Identifier is the identity of the system level, the value of an integral type

The behavior of the user (Uid/gid) is a sequence of processes, so the user identity is actually the identity of the uid/gid of the process.

Eg: the uid of a user is 0, and the UID of all processes that this user operates is 0

Linux Multi-user and multi-user boundaries