58 lines
2.3 KiB
Markdown
58 lines
2.3 KiB
Markdown
Native Unikraft Microkernel Build for Zig libraries
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===================================================
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Building
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--------
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Everything assumes Linux on x86_64, though some trivial changes should allow
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aarch64. Install the following:
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* [Zig](https://ziglang.org). Versions 0.12.0 and 0.13.0 should work
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* [QEMU](https://www.qemu.org/download/#linux)
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* [Kraftkit](https://unikraft.org/docs/cli/install)
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Then run `zig build run` and everything will compile and run. The zig source
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code is all in the `ziggy` directory. This is all prototype level code at this
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point.
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Reproducibility
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---------------
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This build is not reproducible at the moment. The problem is that we need v0.17.0
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or higher (this may be an issue with QEMU installed version, so YMMV). Kraftfile
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is designed to pin to a specific version, but as of this writing, versions of
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unikraft core post 0.16.1 are not listed in https://manifests.kraftkit.sh/unikraft.yaml,
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and as a result cannot be used, so we are forced to use "stable" as the version.
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undefined.c
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-----------
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This file aims to fill in all the undefined symbols that are referenced when
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a zig project links libC (necessary for unikraft kernel development). However,
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this is very incomplete. The `.config.hellowworld_qemu-x86_64` file, usually
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managed by the invocation of the TUI started by `kraft menu`, will add/remove
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features that result in various libc symbols being implemented. A few
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`#ifdef` statements exist currently, but even the few that are in there aren't
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quite right...this file is mostly a "hack around until it works" effort.
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Knowing that this is an initial effort, care was put into making sure that
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when a symbol is actually **used** at runtime, the unikernel will crash after
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posting a message indicating the specific function call that was involved. This
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is designed to either a) correct the configuration using `kraft menu` or
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b) provide an implementation directly in `undefined.c`. In some cases, I prefer
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the implementation in `undefined.c`, most specifically the `write` function,
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which will output stderr messages in red.
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Notes
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-----
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The build script basically runs these commands:
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```sh
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(cd ziggy && zig build)
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LIBZIGGY=$(pwd)/ziggy/zig-out/lib/libziggy.a kraft build --plat qemu --arch x86_64 --log-level debug --log-type basic
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kraft run --plat qemu --arch x86_64
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```
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