gcplogs: forcibly set HOME on static UNIX binary #29478

AkihiroSuda · 2016-12-16T10:00:20Z

- What I did
Fix #29344

The PR consists of 3 commits, but the first and the second one are dupe of #29475 for vendoring golang/oauth2@96382aa .
Please review the latest commit in this PR. (I will rebase this PR when #29475 is merged)
EDIT: rebased

- How I did it

If HOME is not set, the gcplogs logging driver will call os/user.Current() via oauth2/google.
However, in static binary, os/user.Current() leads to segfault due to a glibc issue that won't be fixed
in a short term. (golang/go#13470, https://sourceware.org/bugzilla/show_bug.cgi?id=19341)

So this PR forcibly sets HOME so as to avoid call to os/user/Current().

- How to verify it

Build the static daemon binary (make binary)
Start the daemon without HOME (typically, just starting the daemon via systemd is enough)
Make sure the daemon prints a warning log: level=warning msg="gcplogs requires HOME to be set for static daemon binary. Forcibly setting HOME to /root."
Do docker run --rm --log-driver=gcplogs busybox echo hello many times and make sure all of them succeeds without SEGV

- Description for the changelog

gcplogs: forcibly set HOME on static UNIX binary

- A picture of a cute animal (not mandatory but encouraged)

AkihiroSuda · 2016-12-16T10:13:58Z

windowsRS1 failing because go-autogen.ps1 does not add IAmStatic

00:08:18.526 # github.com/docker/docker/daemon/logger/gcplogs
00:08:18.527 daemon\logger\gcplogs\gcplogging.go:126: undefined: dockerversion.IAmStatic

I'll fix later

thaJeztah · 2016-12-16T10:19:14Z

Is this something to integrate into https://github.com/docker/docker/blob/master/pkg/homedir/homedir.go, or better kept separate?

AkihiroSuda · 2016-12-16T10:37:50Z

@thaJeztah
Ah, I didn't notice the homedir pkg.
I'm ok to move the function to the homedir pkg, but it will be a separate function.

Existing homedir.Get():

calls os/user.Current()
Should work with non-file database (e.g. LDAP)

The function I'll add to homedir (I could not come up with a good function name.. Maybe GetStatic?)

directly read /etc/passwd
Should not work with LDAP

justincormack · 2016-12-23T11:17:40Z

daemon/logger/gcplogs/gcplogging.go

+	// However, in static binary, os/user.Current() leads to segfault due to a glibc issue that won't be fixed
+	// in a short term. (golang/go#13470, https://sourceware.org/bugzilla/show_bug.cgi?id=19341)
+	// So we forcibly set HOME so as to avoid call to os/user/Current()
+	if dockerversion.IAmStatic == "true" && runtime.GOOS != "windows" && os.Getenv("HOME") == "" {


This only really needs to be runtime.GOOS == "linux" as it is a glibc bug...

justincormack · 2016-12-23T11:18:29Z

pkg/idtools/idtools_windows.go

+// LookupCurrentHome returns the home directory for the current user.
+// The current implementation for UNIX does not call os/user.Current(), because a call to os/user.Current()
+// in a static binary leads to segfault due to a glibc issue that won't be fixed in a short term.
+// (#29344, golang/go#13470, https://sourceware.org/bugzilla/show_bug.cgi?id=19341)


Do not need this comment on Windows

justincormack · 2016-12-23T11:34:22Z

Windows CI out of disk space.

justincormack · 2016-12-24T12:53:18Z

@AkihiroSuda ok windows running again but the test failure is real:

12:17:01 # github.com/docker/docker/daemon/logger/gcplogs
12:17:01 daemon\logger\gcplogs\gcplogging.go:126: undefined: dockerversion.IAmStatic

AkihiroSuda · 2016-12-26T06:52:35Z

@thaJeztah @justincormack
Updated PR and now CI green

thaJeztah · 2016-12-27T15:26:17Z

pkg/homedir/homedir_linux.go

+// system, because a call to os/user.Current() in a static binary leads to
+// segfault due to a glibc issue that won't be fixed in a short term.
+// (#29344, golang/go#13470, https://sourceware.org/bugzilla/show_bug.cgi?id=19341)
+func GetStatic() (string, error) {


Wondering; should we have a dummy GetStatic() in non-linux files? What's the general approach in this situation?

Since the issue is specific to glibc's TLS handling, I think we do not need dummies for non-linux files, but I can add them if needed.

(I'm not sure this is an issue for non-Linux glibc-based systems. e.g. Debian GNU/kFreeBSD(?) 😅 )

It was more that GetStatic() is an exported function, so I was wondering if it's common practice to have an exported function only available on some platforms/architectures.

Change itself looks good to me

cpuguy83 · 2016-12-28T16:55:45Z

Needs a rebase.

justincormack · 2016-12-28T18:22:06Z

It needs the first two commits removing as #29475 is merged

Fix moby#29344 If HOME is not set, the gcplogs logging driver will call os/user.Current() via oauth2/google. However, in static binary, os/user.Current() leads to segfault due to a glibc issue that won't be fixed in a short term. (golang/go#13470, https://sourceware.org/bugzilla/show_bug.cgi?id=19341) So we forcibly set HOME so as to avoid call to os/user/Current(). Signed-off-by: Akihiro Suda <suda.akihiro@lab.ntt.co.jp>

AkihiroSuda · 2016-12-29T03:19:19Z

@thaJeztah @cpuguy83 @justincormack Rebased and added dummy pkg/homedir/homedir_others.go

thaJeztah

LGTM, thanks!

stevvooe · 2017-12-01T02:36:44Z

At this point, the bug doesn't seem to exist anymore. What are the plans to back out this code?

AkihiroSuda · 2017-12-01T02:43:06Z

@stevvooe

How was this fixed?
The status of https://sourceware.org/bugzilla/show_bug.cgi?id=19341 is still SUSPENDED.

stevvooe · 2017-12-01T02:44:28Z

Impossible to tell. I guess not, as I was able to reproduce.

Why do we continue to use broken glibc? What a constant piece of junk...

This commit also eliminates call for `os/user.Current()`, which segfaults when glibc is statically linkedin. (moby/moby#29478) Signed-off-by: Akihiro Suda <suda.akihiro@lab.ntt.co.jp>

GordonTheTurtle added the status/0-triage label Dec 16, 2016

AkihiroSuda mentioned this pull request Dec 16, 2016

Vendor gcplogs deps #29475

Merged

thaJeztah added status/2-code-review and removed status/0-triage labels Dec 16, 2016

AkihiroSuda mentioned this pull request Dec 16, 2016

gcplogs logging driver segfaults (static binary only) #29344

Closed

ehazlett added the status/failing-ci Indicates that the PR in its current state fails the test suite label Dec 19, 2016

justincormack reviewed Dec 23, 2016

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AkihiroSuda force-pushed the fix-gcplogs-29344 branch from b9f3656 to 30c71d4 Compare December 26, 2016 03:14

AkihiroSuda removed the status/failing-ci Indicates that the PR in its current state fails the test suite label Dec 26, 2016

AkihiroSuda force-pushed the fix-gcplogs-29344 branch from 30c71d4 to 2bf2779 Compare December 26, 2016 03:17

justincormack approved these changes Dec 27, 2016

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thaJeztah reviewed Dec 27, 2016

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AkihiroSuda force-pushed the fix-gcplogs-29344 branch from 2bf2779 to b86e3be Compare December 29, 2016 03:17

thaJeztah added the impact/changelog label Dec 29, 2016

thaJeztah approved these changes Dec 29, 2016

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thaJeztah merged commit f635cf0 into moby:master Dec 29, 2016

GordonTheTurtle added this to the 1.14.0 milestone Dec 29, 2016

clnperez mentioned this pull request Jan 10, 2017

Add manifest command to docker cli #27455

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yongtang mentioned this pull request Aug 30, 2017

[RFC]/[WIP] Update go to 1.9 #34671

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yongtang mentioned this pull request Aug 30, 2017

Bump Go to 1.9.2 #33892

Merged

AkihiroSuda mentioned this pull request Dec 1, 2017

cmd/containerd-shim: require unix socket credentials containerd/containerd#1849

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AkihiroSuda mentioned this pull request Dec 1, 2017

unixcreds: use euid instead of uid containerd/ttrpc#14

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This was referenced Dec 31, 2022

daemon/logger/gcplogs: remove ensureHomeIfIAmStatic workaround #44722

Merged

[23.0 backport] daemon/logger/gcplogs: remove ensureHomeIfIAmStatic workaround #44724

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gcplogs: forcibly set HOME on static UNIX binary #29478

gcplogs: forcibly set HOME on static UNIX binary #29478

AkihiroSuda commented Dec 16, 2016 •

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gcplogs: forcibly set HOME on static UNIX binary #29478

gcplogs: forcibly set HOME on static UNIX binary #29478

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