mirror of https://github.com/microsoft/WSL
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 |