Woof.LinuxAdmin 6.2.0

Woof.LinuxAdmin

A part of the Woof Tookit by CodeDog.

Distributed under MIT License. (c)2021 by CodeDog, All rights reserved.

Some advanced application features require some system administration tasks to be performed before they can be used.

The common tasks are:

• Installing and controlling system services,
• System users and groups management,
• File system permission management.

When the code is executed with administrative privileges, it makes sense that it could configure the target system automatically without requiring much additional system administration.

As the .NET platform already contains most of the tools itself, they are currently available for Windows OS only. Woof.LinuxAdmin provides unified API for both Linux and Windows.

Linux user information, group information, file system entry information: they are all supported by .NET only partially, translated to their Windows equivalents.

Woof.LinuxAdmin provides native Linux types:

• UserInfo,
• GroupInfo,
• StatInfo.

The types are fully managed ones, not directly compatible with the corresponding Linux kernel structures.

Linux file system entry binary mode IS identical with the uint type used in the kernel.

Of course all file system manipulation tools can operate both on single entries and entire directory trees.

To register, unregister or control system services use Woof.ServiceInstaller module.

Design

The core of the library is Linux native Syscall class. It contains the signatures for libc system calls. There is a minimalistic set of features used, just to enable basic Linux file system operations.

Original naming convention is dropped for .NET naming and signatures style.

The managed functions sit in Linux static class.

The functions mostly return bool values indicating that the operation was successful.

AddSystemUserAsync(), AddSystemGroupAsync() methods

The only asynchronous methods in Linux static class. They are asynchronous since they use shell to call useradd and groupadd.

Chmod(), ChmodR(), Chown(), ChownR()

Chmod changes permissions on a file system entry. You can provide permissions as follows:

• octal string, like "664" (absolute read/write for user and group, read for others)
• relative string, like "ug+rw,o-w", "+x" and so on,
• binary - as uint Linux mode.

Conversions between string, uint and Permissions are made implicitly.

Special permission "X" also works, setting executable bit if the entry is a directory or has at least one executable bit set.

It is important, that the execute permissions cannot be set on unreadable entries. When the entry doesn't have a read permission for the specified target it's execute bit will not be set for that target.

Chown changes an owner of a file system entry.

To change permissions and / or owner for all entries in a directory including the directory itself use ChmodR() and ChownR() methods.

Other tools

For the administration it's useful to check if the program has administrative privileges. To do so use CurrentUser.IsAdmin property.

You can even check if the program was run on Linux with sudo command, and not from the root account, to do so get the CurrentUser.IsSudo property.

To get detailed information about the current Linux user use:

• Linux.CurrentProcessUser,
• CurrentUser.BehindSudo

It can be useful to access the user's Directory (Linux home).

Use StatInfo for detailed Linux file system entry properties, use UserInfo for detailed user information, user GroupInfo for detailed group information including its members.

Linux.HomeDirectory contains home directory of the current user, also in case if the user run the program with sudo.

You can also resolve paths containing ~ using the HomeDirectory property with Linux.ResolveUserPath().

Performance hint

To set absolute permissions use octal strings (or binary) to skip calling stat on each entry.

Release notes

This version is a part of the 6.2, new top quality branch. As the strict separation of concerns rule is applied, shell access and data protection features were moved to the separate packages.

Disclaimer

Woof Toolkit is a work in progress in constant development, however it's carefully maintained with production code quality.

PLEASE report all issues on GitHub!

Describe how to reproduce an issue. Also feel free to suggest new features or improvements.