9565c19ef0
This is much better than bindgen because it's fully safe. It's much more ergonomic too: - Invoke Rust methods-on-structs just like C++ methods-on-structs - Rust `Result<>` is translated automatically to exceptions See https://cxx.rs/context.html for more.
68 lines
1.9 KiB
Rust
68 lines
1.9 KiB
Rust
use crate::ffiutil;
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use anyhow::Result;
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use ffiutil::ffi_view_openat_dir;
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use openat_ext::OpenatDirExt;
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/// Guard for running logic in a context with temporary /etc.
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///
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/// We have a messy dance in dealing with /usr/etc and /etc; the
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/// current model is basically to have it be /etc whenever we're running
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/// any code.
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#[derive(Debug)]
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pub struct TempEtcGuard {
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rootfs: openat::Dir,
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renamed_etc: bool,
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}
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pub fn prepare_tempetc_guard(rootfs: i32) -> Result<Box<TempEtcGuard>> {
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let rootfs = ffi_view_openat_dir(rootfs);
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let has_usretc = rootfs.exists("usr/etc")?;
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let mut renamed_etc = false;
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if has_usretc {
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// In general now, we place contents in /etc when running scripts
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rootfs.local_rename("usr/etc", "etc")?;
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// But leave a compat symlink, as we used to bind mount, so scripts
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// could still use that too.
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rootfs.symlink("usr/etc", "../etc")?;
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renamed_etc = true;
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}
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Ok(Box::new(TempEtcGuard {
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rootfs,
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renamed_etc,
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}))
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}
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impl TempEtcGuard {
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/// Remove the temporary /etc, and destroy the guard.
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pub fn undo(&self) -> anyhow::Result<()> {
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if self.renamed_etc {
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/* Remove the symlink and swap back */
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self.rootfs.remove_file("usr/etc")?;
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self.rootfs.local_rename("etc", "usr/etc")?;
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}
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Ok(())
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}
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}
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#[cfg(test)]
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mod test {
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use super::*;
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use std::os::unix::prelude::*;
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#[test]
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fn basic() -> Result<()> {
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let td = tempfile::tempdir()?;
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let d = openat::Dir::open(td.path())?;
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let g = super::prepare_tempetc_guard(d.as_raw_fd())?;
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g.undo()?;
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d.ensure_dir_all("usr/etc/foo", 0o755)?;
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assert!(!d.exists("etc/foo")?);
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let g = super::prepare_tempetc_guard(d.as_raw_fd())?;
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assert!(d.exists("etc/foo")?);
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g.undo()?;
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assert!(!d.exists("etc")?);
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assert!(d.exists("usr/etc/foo")?);
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Ok(())
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}
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}
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