fix(vfs) Opening in append-mode must ignore seek operations #2545
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When opening a file with the `append` option turned on, all `seek` operations must be ignored. As described by [`open(2)`](https://man7.org/linux/man-pages/man2/open.2.html), the `O_APPEND` option describes this behavior well: > Before each write(2), the file offset is positioned at > the end of the file, as if with lseek(2). The > modification of the file offset and the write operation > are performed as a single atomic step. > > O_APPEND may lead to corrupted files on NFS filesystems > if more than one process appends data to a file at once. > This is because NFS does not support appending to a file, > so the client kernel has to simulate it, which can't be > done without a race condition. This patch implements that behavior. Also, this patch rewind the file cursor if opened in read-mode.
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2546: test(wasi) Running all WASI tests with `wasmer_vfs::mem_fs` too r=Hywan a=Hywan # Description This WIP PR updates our WASI test framework to specifically test with `wasmer_vfs::host_fs` (the default, as of now) _and_ with `wasmer_vfs::mem_fs` (🆕!). Bug trophies: * #2545 * #2550 * #2551 # Review - [ ] Add a short description of the change to the CHANGELOG.md file Co-authored-by: Ivan Enderlin <ivan@mnt.io>
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Description
When opening a file with the
appendoption turned on, allseekoperations must be ignored. As described by
open(2), theO_APPENDoption describes this behavior well:This patch implements that behavior.
Also, this patch rewind the file cursor if opened in read-mode.