Restrict the preview1 implementation of fd_read to one iovec #8415
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In the wasi-common implementation of
fd_read
for preview1, switch to only reading the first iovec given in a vectored read. This avoids issues with Wiggle's runtime borrow-checker implemented in #8277, which would cause the reads to unconditionally fail when two mutable borrows were taken out on the same memory.While it's not as efficient to perform a single read at a time, it is also valid, as read never promises to read all of the vectors provided.
Co-authored-by: Nick Fitzgerald fitzgen@gmail.com