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Many Microsoft employees have contributed to the Windows Subsystem for Linux, this commit is the result of their work since 2016. The entire history of the Windows Subsystem for Linux can't be shared here, but here's an overview of WSL's history after it moved to it own repository in 2021: Number of commits on the main branch: 2930 Number of contributors: 31 Head over https://github.com/microsoft/WSL/releases for a more detailed history of the features added to WSL since 2021.
36 lines
1.7 KiB
Markdown
36 lines
1.7 KiB
Markdown
# Init
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Init is top level process of a WSL distribution. For WSL1 distributions, it is launched by [wslservice](wslservice.exe.md) (see `src/windows/service/LxssInstance.cpp`) and for WSL2 distributions, it is launched by [mini_init](mini_init.md).
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## WSL2 specific distributions startup
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Each WSL2 distributions runs in a separate mount, pid and UTS namespace. This allows distributions to run in parallel, without "seeing" each other.
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When a WSL2 distribution starts, [mini_init](mini_init.md):
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- Mounts the distribution VHD
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- Clones into a child namespace
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- Chroots in the VHD mountpoint
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- Executes init (see the `LxMiniInitMessageLaunchInit` message).
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While each distribution runs in its own mount namespace, the `/mnt/wsl` mountpoint is shared between all distributions.
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## Distribution initialization
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Once started, the `init` process performs various initialization tasks such as:
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- Mounting `/proc`, `/sys` and `/dev`
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- Configuring cgroups
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- Registering the binfmt interpreter (see [interop](interop.md))
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- Parsing [/etc/wsl.conf](https://learn.microsoft.com/windows/wsl/wsl-config)
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- Starting systemd (see [systemd](systemd.md))
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- Mounting `drvfs` drives (See [drvfs](drvfs.md))
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- Configuring `wslg` (see [wslg](https://github.com/microsoft/wslg))
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## Running the distribution
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Once ready, `init` establishes either an `lxbus` (WSL1) or an `hvsocket` (WSL2) connection to [wslservice](wslservice.exe.md). This channel is used to transmit various commands to `init` (see `src/shared/inc/lxinitshared.h`), such as:
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- `LxInitMessageInitialize`: Configure the distribution
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- `LxInitMessageCreateSession`: Create a new session leader. See [session leader](session-leader.md)
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- `LxInitMessageTerminateInstance`: Terminate the distribution |