feat: use a Rust tool to do the PATH manipulations

Overkill? Yes. Fuck bash? Also yes.

5 files changed, 656 insertions, 0 deletions

diff --git a/scripts/native-utils/Cargo.lock b/scripts/native-utils/Cargo.lock
new file mode 100644
index 0000000..34a28f6
--- /dev/null
+++ b/scripts/native-utils/Cargo.lock
@@ -0,0 +1,462 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "addr2line"
+version = "0.17.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b9ecd88a8c8378ca913a680cd98f0f13ac67383d35993f86c90a70e3f137816b"
+dependencies = [
+ "gimli",
+]
+
+[[package]]
+name = "adler"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f26201604c87b1e01bd3d98f8d5d9a8fcbb815e8cedb41ffccbeb4bf593a35fe"
+
+[[package]]
+name = "anyhow"
+version = "1.0.65"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "98161a4e3e2184da77bb14f02184cdd111e83bbbcc9979dfee3c44b9a85f5602"
+dependencies = [
+ "backtrace",
+]
+
+[[package]]
+name = "autocfg"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d468802bab17cbc0cc575e9b053f41e72aa36bfa6b7f55e3529ffa43161b97fa"
+
+[[package]]
+name = "backtrace"
+version = "0.3.66"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cab84319d616cfb654d03394f38ab7e6f0919e181b1b57e1fd15e7fb4077d9a7"
+dependencies = [
+ "addr2line",
+ "cc",
+ "cfg-if",
+ "libc",
+ "miniz_oxide",
+ "object",
+ "rustc-demangle",
+]
+
+[[package]]
+name = "bitflags"
+version = "1.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
+
+[[package]]
+name = "cc"
+version = "1.0.73"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2fff2a6927b3bb87f9595d67196a70493f627687a71d87a0d692242c33f58c11"
+
+[[package]]
+name = "cfg-if"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
+
+[[package]]
+name = "clap"
+version = "4.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f13b9c79b5d1dd500d20ef541215a6423c75829ef43117e1b4d17fd8af0b5d76"
+dependencies = [
+ "bitflags",
+ "clap_derive",
+ "clap_lex",
+ "is-terminal",
+ "once_cell",
+ "strsim",
+ "termcolor",
+]
+
+[[package]]
+name = "clap_derive"
+version = "4.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "684a277d672e91966334af371f1a7b5833f9aa00b07c84e92fbce95e00208ce8"
+dependencies = [
+ "heck",
+ "proc-macro-error",
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "clap_lex"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "783fe232adfca04f90f56201b26d79682d4cd2625e0bc7290b95123afe558ade"
+dependencies = [
+ "os_str_bytes",
+]
+
+[[package]]
+name = "errno"
+version = "0.2.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f639046355ee4f37944e44f60642c6f3a7efa3cf6b78c78a0d989a8ce6c396a1"
+dependencies = [
+ "errno-dragonfly",
+ "libc",
+ "winapi",
+]
+
+[[package]]
+name = "errno-dragonfly"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "aa68f1b12764fab894d2755d2518754e71b4fd80ecfb822714a1206c2aab39bf"
+dependencies = [
+ "cc",
+ "libc",
+]
+
+[[package]]
+name = "gimli"
+version = "0.26.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "22030e2c5a68ec659fde1e949a745124b48e6fa8b045b7ed5bd1fe4ccc5c4e5d"
+
+[[package]]
+name = "heck"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2540771e65fc8cb83cd6e8a237f70c319bd5c29f78ed1084ba5d50eeac86f7f9"
+
+[[package]]
+name = "hermit-abi"
+version = "0.2.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ee512640fe35acbfb4bb779db6f0d80704c2cacfa2e39b601ef3e3f47d1ae4c7"
+dependencies = [
+ "libc",
+]
+
+[[package]]
+name = "io-lifetimes"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e7d6c6f8c91b4b9ed43484ad1a938e393caf35960fce7f82a040497207bd8e9e"
+dependencies = [
+ "libc",
+ "windows-sys",
+]
+
+[[package]]
+name = "is-terminal"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "28dfb6c8100ccc63462345b67d1bbc3679177c75ee4bf59bf29c8b1d110b8189"
+dependencies = [
+ "hermit-abi",
+ "io-lifetimes",
+ "rustix",
+ "windows-sys",
+]
+
+[[package]]
+name = "kernlog"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f0dd79b6ea06a97c93bc5587fba4c2ed6d723b939d35d5e3fb3c6870d12e6d17"
+dependencies = [
+ "libc",
+ "log",
+]
+
+[[package]]
+name = "libc"
+version = "0.2.133"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c0f80d65747a3e43d1596c7c5492d95d5edddaabd45a7fcdb02b95f644164966"
+
+[[package]]
+name = "linux-raw-sys"
+version = "0.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f051f77a7c8e6957c0696eac88f26b0117e54f52d3fc682ab19397a8812846a4"
+
+[[package]]
+name = "log"
+version = "0.4.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "abb12e687cfb44aa40f41fc3978ef76448f9b6038cad6aef4259d3c095a2382e"
+dependencies = [
+ "cfg-if",
+]
+
+[[package]]
+name = "memchr"
+version = "2.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2dffe52ecf27772e601905b7522cb4ef790d2cc203488bbd0e2fe85fcb74566d"
+
+[[package]]
+name = "memoffset"
+version = "0.6.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5aa361d4faea93603064a027415f07bd8e1d5c88c9fbf68bf56a285428fd79ce"
+dependencies = [
+ "autocfg",
+]
+
+[[package]]
+name = "miniz_oxide"
+version = "0.5.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "96590ba8f175222643a85693f33d26e9c8a015f599c216509b1a6894af675d34"
+dependencies = [
+ "adler",
+]
+
+[[package]]
+name = "nix"
+version = "0.25.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e322c04a9e3440c327fca7b6c8a63e6890a32fa2ad689db972425f07e0d22abb"
+dependencies = [
+ "autocfg",
+ "bitflags",
+ "cfg-if",
+ "libc",
+ "memoffset",
+ "pin-utils",
+]
+
+[[package]]
+name = "nixos-wsl-utils"
+version = "0.1.0"
+dependencies = [
+ "anyhow",
+ "clap",
+ "kernlog",
+ "log",
+ "nix",
+]
+
+[[package]]
+name = "object"
+version = "0.29.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "21158b2c33aa6d4561f1c0a6ea283ca92bc54802a93b263e910746d679a7eb53"
+dependencies = [
+ "memchr",
+]
+
+[[package]]
+name = "once_cell"
+version = "1.17.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6f61fba1741ea2b3d6a1e3178721804bb716a68a6aeba1149b5d52e3d464ea66"
+
+[[package]]
+name = "os_str_bytes"
+version = "6.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9b7820b9daea5457c9f21c69448905d723fbd21136ccf521748f23fd49e723ee"
+
+[[package]]
+name = "pin-utils"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8b870d8c151b6f2fb93e84a13146138f05d02ed11c7e7c54f8826aaaf7c9f184"
+
+[[package]]
+name = "proc-macro-error"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "da25490ff9892aab3fcf7c36f08cfb902dd3e71ca0f9f9517bea02a73a5ce38c"
+dependencies = [
+ "proc-macro-error-attr",
+ "proc-macro2",
+ "quote",
+ "syn",
+ "version_check",
+]
+
+[[package]]
+name = "proc-macro-error-attr"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a1be40180e52ecc98ad80b184934baf3d0d29f979574e439af5a55274b35f869"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "version_check",
+]
+
+[[package]]
+name = "proc-macro2"
+version = "1.0.50"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6ef7d57beacfaf2d8aee5937dab7b7f28de3cb8b1828479bb5de2a7106f2bae2"
+dependencies = [
+ "unicode-ident",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.23"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8856d8364d252a14d474036ea1358d63c9e6965c8e5c1885c18f73d70bff9c7b"
+dependencies = [
+ "proc-macro2",
+]
+
+[[package]]
+name = "rustc-demangle"
+version = "0.1.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7ef03e0a2b150c7a90d01faf6254c9c48a41e95fb2a8c2ac1c6f0d2b9aefc342"
+
+[[package]]
+name = "rustix"
+version = "0.36.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d4fdebc4b395b7fbb9ab11e462e20ed9051e7b16e42d24042c776eca0ac81b03"
+dependencies = [
+ "bitflags",
+ "errno",
+ "io-lifetimes",
+ "libc",
+ "linux-raw-sys",
+ "windows-sys",
+]
+
+[[package]]
+name = "strsim"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "73473c0e59e6d5812c5dfe2a064a6444949f089e20eec9a2e5506596494e4623"
+
+[[package]]
+name = "syn"
+version = "1.0.107"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1f4064b5b16e03ae50984a5a8ed5d4f8803e6bc1fd170a3cda91a1be4b18e3f5"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
+[[package]]
+name = "termcolor"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "be55cf8942feac5c765c2c993422806843c9a9a45d4d5c407ad6dd2ea95eb9b6"
+dependencies = [
+ "winapi-util",
+]
+
+[[package]]
+name = "unicode-ident"
+version = "1.0.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "84a22b9f218b40614adcb3f4ff08b703773ad44fa9423e4e0d346d5db86e4ebc"
+
+[[package]]
+name = "version_check"
+version = "0.9.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "49874b5167b65d7193b8aba1567f5c7d93d001cafc34600cee003eda787e483f"
+
+[[package]]
+name = "winapi"
+version = "0.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c839a674fcd7a98952e593242ea400abe93992746761e38641405d28b00f419"
+dependencies = [
+ "winapi-i686-pc-windows-gnu",
+ "winapi-x86_64-pc-windows-gnu",
+]
+
+[[package]]
+name = "winapi-i686-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
+
+[[package]]
+name = "winapi-util"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "70ec6ce85bb158151cae5e5c87f95a8e97d2c0c4b001223f33a334e3ce5de178"
+dependencies = [
+ "winapi",
+]
+
+[[package]]
+name = "winapi-x86_64-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
+
+[[package]]
+name = "windows-sys"
+version = "0.42.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5a3e1820f08b8513f676f7ab6c1f99ff312fb97b553d30ff4dd86f9f15728aa7"
+dependencies = [
+ "windows_aarch64_gnullvm",
+ "windows_aarch64_msvc",
+ "windows_i686_gnu",
+ "windows_i686_msvc",
+ "windows_x86_64_gnu",
+ "windows_x86_64_gnullvm",
+ "windows_x86_64_msvc",
+]
+
+[[package]]
+name = "windows_aarch64_gnullvm"
+version = "0.42.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8c9864e83243fdec7fc9c5444389dcbbfd258f745e7853198f365e3c4968a608"
+
+[[package]]
+name = "windows_aarch64_msvc"
+version = "0.42.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4c8b1b673ffc16c47a9ff48570a9d85e25d265735c503681332589af6253c6c7"
+
+[[package]]
+name = "windows_i686_gnu"
+version = "0.42.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "de3887528ad530ba7bdbb1faa8275ec7a1155a45ffa57c37993960277145d640"
+
+[[package]]
+name = "windows_i686_msvc"
+version = "0.42.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bf4d1122317eddd6ff351aa852118a2418ad4214e6613a50e0191f7004372605"
+
+[[package]]
+name = "windows_x86_64_gnu"
+version = "0.42.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c1040f221285e17ebccbc2591ffdc2d44ee1f9186324dd3e84e99ac68d699c45"
+
+[[package]]
+name = "windows_x86_64_gnullvm"
+version = "0.42.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "628bfdf232daa22b0d64fdb62b09fcc36bb01f05a3939e20ab73aaf9470d0463"
+
+[[package]]
+name = "windows_x86_64_msvc"
+version = "0.42.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "447660ad36a13288b1db4d4248e857b510e8c3a225c822ba4fb748c0aafecffd"
diff --git a/scripts/native-utils/Cargo.toml b/scripts/native-utils/Cargo.toml
new file mode 100644
index 0000000..14482fc
--- /dev/null
+++ b/scripts/native-utils/Cargo.toml
@@ -0,0 +1,19 @@
+[package]
+name = "nixos-wsl-utils"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+anyhow = { version = "*", features = ["backtrace"] }
+nix = { version = "*", features = ["process"] }
+log = "*"
+kernlog = "*"
+clap = { version = "*", features = ["derive"] }
+
+[[bin]]
+name = "systemd-shim"
+path = "src/shim.rs"
+
+[[bin]]
+name = "split-path"
+path = "src/split_path.rs"
diff --git a/scripts/native-utils/default.nix b/scripts/native-utils/default.nix
new file mode 100644
index 0000000..838aa39
--- /dev/null
+++ b/scripts/native-utils/default.nix
@@ -0,0 +1,8 @@
+{ rustPlatform }:
+rustPlatform.buildRustPackage {
+  pname = "nixos-wsl-utils";
+  version = "1.0.0";
+
+  src = ./.;
+  cargoLock.lockFile = ./Cargo.lock;
+}
diff --git a/scripts/native-utils/src/shim.rs b/scripts/native-utils/src/shim.rs
new file mode 100644
index 0000000..504335c
--- /dev/null
+++ b/scripts/native-utils/src/shim.rs
@@ -0,0 +1,129 @@
+use anyhow::Context;
+use nix::errno::Errno;
+use nix::mount::{mount, MsFlags};
+use nix::sys::wait::{waitid, Id, WaitPidFlag};
+use nix::unistd::Pid;
+use std::env;
+use std::fs::{create_dir_all, metadata, remove_dir_all, remove_file, OpenOptions};
+use std::os::unix::io::{FromRawFd, IntoRawFd};
+use std::os::unix::process::CommandExt;
+use std::path::Path;
+use std::process::{Command, Stdio};
+
+fn unscrew_dev_shm() -> anyhow::Result<()> {
+    log::trace!("Unscrewing /dev/shm...");
+
+    let dev_shm = Path::new("/dev/shm");
+
+    if dev_shm.is_symlink() {
+        remove_file(dev_shm).context("When removing /dev/shm symlink")?;
+    } else if dev_shm.is_dir() {
+        remove_dir_all(dev_shm).context("When removing old /dev/shm")?;
+    }
+
+    create_dir_all("/dev/shm").context("When creating new /dev/shm")?;
+    mount(
+        Some("/run/shm"),
+        "/dev/shm",
+        None::<&str>,
+        MsFlags::MS_MOVE,
+        None::<&str>,
+    )
+    .context("When relocating /dev/shm")?;
+    mount(
+        Some("/dev/shm"),
+        "/run/shm",
+        None::<&str>,
+        MsFlags::MS_BIND,
+        None::<&str>,
+    )
+    .context("When bind mounting /run/shm to /dev/shm")?;
+
+    Ok(())
+}
+
+fn real_main() -> anyhow::Result<()> {
+    if metadata("/dev/shm")
+        .context("When checking /dev/shm")?
+        .is_symlink()
+    {
+        unscrew_dev_shm()?;
+    } else {
+        log::trace!("/dev/shm is not a symlink, leaving as-is...");
+    };
+
+    log::trace!("Remounting / shared...");
+
+    mount(
+        None::<&str>,
+        "/",
+        None::<&str>,
+        MsFlags::MS_REC | MsFlags::MS_SHARED,
+        None::<&str>,
+    )
+    .context("When remounting /")?;
+
+    log::trace!("Remounting /nix/store read-only...");
+
+    mount(
+        Some("/nix/store"),
+        "/nix/store",
+        None::<&str>,
+        MsFlags::MS_BIND,
+        None::<&str>,
+    )
+    .context("When bind mounting /nix/store")?;
+
+    mount(
+        Some("/nix/store"),
+        "/nix/store",
+        None::<&str>,
+        MsFlags::MS_BIND | MsFlags::MS_REMOUNT | MsFlags::MS_RDONLY,
+        None::<&str>,
+    )
+    .context("When remounting /nix/store read-only")?;
+
+    log::trace!("Running activation script...");
+
+    let kmsg_fd = OpenOptions::new()
+        .write(true)
+        .open("/dev/kmsg")
+        .context("When opening /dev/kmsg")?
+        .into_raw_fd();
+
+    let child = Command::new("/nix/var/nix/profiles/system/activate")
+        .env("LANG", "C.UTF-8")
+        // SAFETY: we just opened this
+        .stdout(unsafe { Stdio::from_raw_fd(kmsg_fd) })
+        .stderr(unsafe { Stdio::from_raw_fd(kmsg_fd) })
+        .spawn()
+        .context("When activating")?;
+
+    let pid = Pid::from_raw(child.id() as i32);
+
+    // If the child catches SIGCHLD, `waitid` will wait for it to exit, then return ECHILD.
+    // Why? Because POSIX is terrible.
+    let result = waitid(Id::Pid(pid), WaitPidFlag::WEXITED);
+    match result {
+        Ok(_) | Err(Errno::ECHILD) => {}
+        Err(e) => return Err(e).context("When waiting"),
+    };
+
+    log::trace!("Spawning real systemd...");
+
+    // if things go right, we will never return from here
+    Err(
+        Command::new("/nix/var/nix/profiles/system/systemd/lib/systemd/systemd")
+            .arg0(env::args_os().next().expect("arg0 missing"))
+            .args(env::args_os().skip(1))
+            .exec()
+            .into(),
+    )
+}
+
+fn main() {
+    env::set_var("RUST_BACKTRACE", "1");
+    kernlog::init().expect("Failed to set up logger...");
+    let result = real_main();
+    log::error!("Error: {:?}", result);
+}
diff --git a/scripts/native-utils/src/split_path.rs b/scripts/native-utils/src/split_path.rs
new file mode 100644
index 0000000..dd10745
--- /dev/null
+++ b/scripts/native-utils/src/split_path.rs
@@ -0,0 +1,38 @@
+use std::env;
+
+use clap::Parser;
+
+#[derive(Parser, Debug)]
+struct Args {
+  #[arg(long)]
+  automount_root: String,
+
+  #[arg(long)]
+  include_interop: bool,
+}
+
+fn main() -> anyhow::Result<()> {
+  let args = Args::parse();
+
+  let path = env::var("PATH")?;
+
+  let mut native = vec![];
+  let mut interop = vec![];
+
+  for part in path.split(':') {
+    if part.starts_with(&args.automount_root) {
+      interop.push(part);
+    } else {
+      native.push(part);
+    }
+  }
+
+  if args.include_interop {
+    native.extend(&interop);
+  };
+
+  println!("export PATH='{}'", native.join(":"));
+  println!("export WSLPATH='{}'", interop.join(":"));
+
+  Ok(())
+}