Basic fcntl-style locking. #555
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Add an `fcntl_lock` function implementing fcntl-style process-associated locking. Currently this only supports locking the entire file.
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cgwalters
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Mar 4, 2023
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Somewhat superficial LGTM
| #[cfg(target_pointer_width = "32")] | ||
| { | ||
| ret(syscall_readonly!( | ||
| __NR_fcntl64, |
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How about if cfg!(target_pointer_width = "32") { __NR_fcntl64 } else { __NR_fcntl } here and dedup the blocks?
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Unfortunately syscall_readonly! is a macro that does special things with the first parameter and needs it to be a __NR_* literal.
| l_whence: 0, | ||
| l_start: 0, | ||
| l_len: 0, | ||
| ..core::mem::zeroed() |
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Feels like we could rely on core::mem::zeroed() also handling the zero-init for the other members?
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Setting l_len to zero is a special case in the documented behavior of fcntl, so I like keeping it explicit. I've now added more comments about this though.
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Add an
fcntl_lockfunction implementing fcntl-style process-associated locking. Currently this only supports locking the entire file.