Add support for utimensat as an alternative to lutimes
#11751
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OpenBSD doesn't support `lutimes`, but does support `utimensat` which subsumes it. In fact, all the BSDs, Linux, and newer macOS all support it. So lets make this our first choice for the implementation. In addition, let's get rid of the `lutimes` `ENOSYS` special case. The Linux manpage says > ENOSYS > > The kernel does not support this call; Linux 2.6.22 or later is > required. which I think is the origin of this check, but that's a very old version of Linux at this point. The code can be simplified a lot of we drop support for it here (as we've done elsewhere, anyways). Co-Authored-By: John Ericson <John.Ericson@Obsidian.Systems>
edolstra
reviewed
Oct 27, 2024
| }; | ||
| if (utimensat(AT_FDCWD, path.c_str(), times, AT_SYMLINK_NOFOLLOW) == -1) | ||
| throw SysError("changing modification time of '%s' (using `utimensat`)", path); | ||
| #else |
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Do we even need to keep lutimes if all modern OSes support utimensat?
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I am fine either way. I guess I would lean towards removing it in a separate commit/PR so if we need it back it's an easier revert.
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Agree with separating. It may have some knock-on implications like increasing the minimum macOS version enforced in the installer (I think utimensat was added in 10.13).
Ericson2314
approved these changes
Oct 27, 2024
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OpenBSD doesn't support
lutimes, but does supportutimensatwhich subsumes it. In fact, all the BSDs, Linux, and newer macOS all support it. So lets make this our first choice for the implementation.In addition, let's get rid of the
lutimesENOSYSspecial case. The Linux manpage sayswhich I think is the origin of this check, but that's a very old version of Linux at this point. The code can be simplified a lot of we drop support for it here (as we've done elsewhere, anyways).
Motivation
We've been working towards a more functional nix on various *BSD systems. This fixes a nonessential feature, and is useful i combination with #11750 which fixes build on OpenBSD
Context
OpenBSD does not support the
lutimessyscall to mtime of a symlink. However, it supports the commonutimensatsyscall that allows setting mtimes with nanosecond precision for symlinks.As part of the change, @Ericson2314 noticed that
lutimeshas been in Linux for 17 years and the fallback is no longer required, making it easier to clean up the code.Priorities and Process
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