Bug 225324 - errno.h does not define ETIME
Summary: errno.h does not define ETIME
Status: New
Alias: None
Product: Base System
Classification: Unclassified
Component: kern (show other bugs)
Version: CURRENT
Hardware: Any Any
: --- Affects Only Me
Assignee: freebsd-bugs mailing list
Depends on:
Reported: 2018-01-19 18:52 UTC by Greg V
Modified: 2018-01-20 11:29 UTC (History)
1 user (show)

See Also:


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Description Greg V 2018-01-19 18:52:49 UTC
We do not define the XSI STREAMS errors that are defined in NetBSD, Linux and illumos:




Of course no one cares about XSI STREAMS, but e.g. drivers originating from Linux have (ab)used ETIME to mean whatever arbitrary timeout they wanted.

Currently, we have #define ETIME ETIMEDOUT in LinuxKPI (and cddl/contrib/opensolaris/uts/common/fs/zfs/zcp.c).

The most notable drivers that rely on this are DRM/KMS graphics drivers. So currently, Mesa has to do the #define ETIME ETIMEDOUT thing too, e.g.:


This is pretty bad, and Mesa upstream does not want to do that.

We need to either #define ETIME ETIMEDOUT in errno.h, or define it as a new error number and get rid of #define ETIME ETIMEDOUT everywhere. The latter is more "proper" (same distinction between the two as on other systems), but slightly more painful (-CURRENT users would have to upgrade both kernel/drm-next-kmod AND Mesa at the same time once).
Comment 1 Ed Maste freebsd_committer 2018-01-20 00:25:25 UTC
Other userland software doesn't compile for this reason, e.g. https://github.com/IAIK/meltdown/issues/14

The "solution" there was:

#ifndef ETIME
#define ETIME 62

which seems strictly worse than either of the two options you describe.

Debian Code Search returns 3470 (Debian) packages referencing ETIME, https://codesearch.debian.net/search?q=ETIME
Some of these are going to cause grief if we start defining ETIME, e.g.:

#ifdef FREEBSD
#   include <pthread.h>
#   include <sys/sem.h>

so it seems like the first thing we'll want to do is perform a ports exp-run with ETIME defined
Comment 2 Greg V 2018-01-20 11:29:54 UTC
(In reply to Ed Maste from comment #1)
Yeah, the ones that define it to ETIMEDOUT when __FreeBSD__ is defined, as opposed to when ETIME is undefined, are going to cause the most pain with the second option.