Date: Sun, 13 Mar 2022 23:17:07 UTC
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=262535 Bug ID: 262535 Summary: Linuxulator sendfile does not support all file descriptors Product: Base System Version: CURRENT Hardware: Any OS: Any Status: New Severity: Affects Some People Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: email@example.com Created attachment 232438 --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=232438&action=edit Patch to add a fallback to Linuxulator sendfile to support any FDs In Linux < 2.6.33, sendfile could only be used to send from a file to a socket. This is the behaviour implemented by the FreeBSD Linuxulator. However, since 2.6.33, sendfile can send from any FD to any other FD, which is not implemented by FreeBSD sendfile or by the Linuxulator. I ran into this problem trying to run the game "Factorio" using the Linuxulator, which relies on sendfile to copy files on disk. Here is another thread on freebsd-emulation describing the same problem: https://firstname.lastname@example.org/msg11340.html Attached is a patch which changes the Linuxulator sendfile such that it will use FreeBSD sendfile where possible, but otherwise fallback on a simple read/write loop for compatibility. I would very much appreciate some feedback on the patch, as I have never contributed to the FreeBSD kernel before. In particular, any suggestion for a better way to choose the buffer size than the arbitrary 8 KB I have hardcoded would be welcome. -- You are receiving this mail because: You are the assignee for the bug.