fs: Work around rustix listxattr c_char wonkiness #50
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See bytecodealliance/rustix#1061 (comment) Basically current rustix 0.38 sometimes may expose the element type as a signed or unsigned variant, depending on the version of linux-raw-sys and rustix feature flags. Add a cast to work around this; if we cared to drop the unsafe we could use the zerocopy crate. Signed-off-by: Colin Walters <[email protected]>
cgwalters
commented
Dec 4, 2024
| // See https://github.com/bytecodealliance/rustix/pull/1061#issuecomment-2518467534 | ||
| // Basically current rustix 0.38 sometimes may expose the element type as a signed | ||
| // or unsigned variant, depending on the version of linux-raw-sys and rustix feature | ||
| // flags. | ||
| let mut names = vec![0; names_size]; |
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A confusing thing here is that type inference is kicking in for the 0 here and we had conflicting requirements before in the wrong case. It'd help to be able to explicitly specify this array as the target type but I don't think rustix exposes that type alias right now even though it probably should because it's part of the public API.
allisonkarlitskaya
approved these changes
Dec 5, 2024
| @@ -149,6 +153,8 @@ impl FilesystemReader<'_> { | |||
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| let mut buffer = [0; 65536]; | |||
| for name in names.split_inclusive(|c| *c == 0) { | |||
| // SAFETY: casting i8 to u8 is safe. | |||
| let name: &[u8] = unsafe { std::mem::transmute(name) }; | |||
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I really wanted to avoid unsafe but my old //fml solution was causing warnings in the case that c_char ended up already being u8. I guess this one won't.
I also expect this to be relatively short-lived until rustix figures out the solution here...
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See bytecodealliance/rustix#1061 (comment) Basically current rustix 0.38 sometimes may expose the element type as a signed or unsigned variant, depending on the version of linux-raw-sys and rustix feature flags.
Add a cast to work around this; if we cared to drop the unsafe we could use the zerocopy crate.