feat(guest): replace musl with picolibc #831
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| ) | ||
| .unwrap_or_default(); | ||
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| let n = bytes.len(); |
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Do we want to assert n <= count?
A wrongly implemented HostRead could cause a buffer overflow
| } | ||
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| let slice = unsafe { core::slice::from_raw_parts(buf as *const u8, count) }; | ||
| let s = core::str::from_utf8(slice).unwrap_or("<invalid utf8>"); |
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question: what do you think of using String::from_utf8_lossy instead? we are doing s.to_string() anyway.
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Sure! As long as from_utf8_lossy doesn't allocate if string is valid utf-8 which I believe is the case?
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It returns a Cow, so, that's correct, but you will need to allocate a string to send it to the host function anyway... so... ¯\_(ツ)_/¯
| [features] | ||
| default = ["libc", "printf"] | ||
| libc = [] # compile musl libc | ||
| printf = [ "libc" ] # compile printf |
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opinion: I would just put everything under the same libc feature
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Sure, I guess any code from libc if not referenced will be DCE anyway 🤷
| pub extern "C" fn write(fd: c_int, buf: *const c_void, count: usize) -> isize { | ||
| // Only stdout (fd=1) and stderr (fd=2) | ||
| if fd != 1 && fd != 2 { | ||
| return count as isize; |
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question: shuoldn't this return -1, or some other indication of error? and set errno?
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Right, I think that in order to support this properly we would need to generate the bindings to libc headers and use that to reference errno, EBADF etc. But then, it might be better to just have picolibc-sys crate. Anyway I agree we should report an error here somehow.
| pub extern "C" fn read(fd: c_int, buf: *mut c_void, count: usize) -> isize { | ||
| // Only stdin (fd=0) and only if HostRead is defined | ||
| if fd != 0 || !CAPS.host_read() { | ||
| return 0; |
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question: should the case of fd != 0 return -1 and set errno instead?
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will help with #282 |
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Signed-off-by: Tomasz Andrzejak <[email protected]>
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