mmap non-zero length #1873
mmap non-zero length #1873
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JonathanWoollett-Light
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I think this is a good improvement. But don't forget a CHANGELOG. Also, what about
mremap, and munmap? The man pages have the same restriction for them. And for msync, a zero-value for the length argument has special meaning, so we should probably turn it into Option<usize>.
| @@ -515,8 +515,9 @@ pub unsafe fn madvise( | |||
| /// # use nix::sys::mman::{mmap, mprotect, MapFlags, ProtFlags}; | |||
| /// # use std::ptr; | |||
| /// const ONE_K: size_t = 1024; | |||
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Updated to fix this.
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| #[test] | ||
| fn test_mmap_anonymous() { | ||
| unsafe { | ||
| let ptr = mmap( | ||
| std::ptr::null_mut(), | ||
| 1, | ||
| NonZeroUsize::new(1).unwrap(), |
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Do you think it would be worthwhile to bring in the nonzero_ext crate just for these tests?
| NonZeroUsize::new(1).unwrap(), | |
| nonzero_ext::nonzero!(1) |
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At this point no, but if NonZeroUsize sees wider usage it may become worthwhile.
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BTW, I took a look through my other crates and found exactly zero places where nonzero_ext would help. It turns out that Option<NonZeroXXX> is a lot more common than NonZeroXXX.
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These changes make sense to me. I think they make sense as separate PRs to keep the changes incremental. |
test/sys/test_mman.rs
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| let one_k_non_zero = NonZeroUsize::new(ONE_K).unwrap(); | ||
| let ten_one_k = one_k_non_zero | ||
| .checked_mul(NonZeroUsize::new(10).unwrap()) | ||
| .unwrap(); |
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I'd hate to raise the MSRV just for this one line in a test. How about this instead?
| let one_k_non_zero = NonZeroUsize::new(ONE_K).unwrap(); | |
| let ten_one_k = one_k_non_zero | |
| .checked_mul(NonZeroUsize::new(10).unwrap()) | |
| .unwrap(); | |
| let ten_one_k = NonZeroUsize::new(10 * 1024).unwrap(); |
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Fixed
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Merge conflict. |
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bors retry |
When calling
mmapthe passed length needs to be greater than zero, else an error is returned:By specifying the argument as
std::num::NonZeroUsizewe eliminate this error case.