snap-confine/nvidia: Support legacy biarch trees for GLVND systems #4559

ikeydoherty · 2018-01-29T10:03:56Z

GLVND systems are well catered for on biarch configurations, however the
older 304 + 340 series will rely on ld.so.conf tricks to mask the system
libGL.so with one in the private libdir/nvidia*/ files. This is seen
consistently across Arch, Fedora and Solus. As such we allow these fallback
paths to work so that users of snapd on glvnd enabled distros with the older
legacy drivers can still enjoy snapd + NVIDIA together.

Signed-off-by: Ikey Doherty [email protected]

GLVND systems are well catered for on biarch configurations, however the older 304 + 340 series will rely on ld.so.conf tricks to mask the system libGL.so with one in the private `libdir/nvidia*/` files. This is seen consistently across Arch, Fedora and Solus. As such we allow these fallback paths to work so that users of snapd on glvnd enabled distros with the older legacy drivers can still enjoy snapd + NVIDIA together. Signed-off-by: Ikey Doherty <[email protected]>

ikeydoherty · 2018-01-29T10:10:33Z

Sample /var/lib/snapd/lib/gl on a GLVND distro (Solus) with the NVIDIA 304 driver: https://hastebin.com/idasofebut - should point out that the primary links are what matter here. Also note NVIDIA 340 provides the libEGL links which in turn would replace the glvnd libEGL in the hostfs portion. And "pure" GLVND still works.

codecov-io · 2018-01-29T11:21:21Z

Codecov Report

Merging #4559 into master will increase coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #4559      +/-   ##
==========================================
+ Coverage   78.18%   78.19%   +<.01%     
==========================================
  Files         456      456              
  Lines       32529    32690     +161     
==========================================
+ Hits        25434    25563     +129     
- Misses       4979     5011      +32     
  Partials     2116     2116

Impacted Files	Coverage Δ
interfaces/builtin/opengl.go	`100% <ø> (ø)`	⬆️
cmd/snap-update-ns/change.go	`87.87% <0%> (-9.63%)`	⬇️
cmd/snap-update-ns/utils.go	`94.71% <0%> (-5.29%)`	⬇️
overlord/hookstate/hookmgr.go	`73.14% <0%> (+1.14%)`	⬆️

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mvo5

LGTM

Conan-Kudo · 2018-01-29T14:31:56Z

Oh goodie, this should fix some of the reported issues in Fedora with NVIDIA, too.

Conan-Kudo · 2018-01-29T14:33:45Z

@mvo5 Could you please cherry pick this into 2.31 for me? This will resolve RH#1442051 for me.

zyga

+1, CC @jdstrand

jdstrand

I'm approving the apparmor changes, but please consider checking if it is actually a symlink since all the comments and die() are reporting this is the case.

jdstrand · 2018-01-29T15:58:57Z

cmd/snap-confine/mount-support-nvidia.c

+
+		// Make sure we don't have some link already (merged GLVND systems)
+		if (lstat(symlink_name, &stat_buf) == 0) {
+			if (unlink(symlink_name) != 0) {


Shouldn't you also be testing if S_IFLNK? lstat() will happily return 0 if regular file or symlink.

The path is inside our hostfs symlink farm that we create, and we only create symlinks, the code doesn't copy files.

Note, the naming here is confusing, but symlink_name is not the source name, it is the target name for the symlink, i.e. the new inode. Confused the hell out of me going through it the first time.

I'll probably do a small update here to use consistent terminology (oldname vs whatever the other one was).

Conan-Kudo · 2018-01-30T06:12:12Z

@ikeydoherty I think I might be confusing myself again, but will the snap-confine mount-support code actually work with legacy nvidia driver stuff installed in /usr/lib64/nvidia*?

c.f.: http://koji.rpmfusion.org/koji/rpminfo?rpmID=171143
c.f.: http://koji.rpmfusion.org/koji/rpminfo?rpmID=213317

ikeydoherty · 2018-01-30T10:08:42Z

Uh it looks like you guys have even more stuff in that directory than I suspected. You have files in there that shouldn't and don't need to be.. Only the libGL needs to be there :/

In that case we'd have to effectively double the copy list to include all of those (frankly incredibly silly) paths.

ikeydoherty · 2018-01-30T10:20:25Z

And TBH @Conan-Kudo it looks like Fedora should be using bind mounts for those nvidia drivers, but my guess is the use of glvnd makes that unfeasible.

What we can do:

Remove 32 vs 64 logic in the "mount" farm. Make the function accept a common ancestor, i.e. /usr/lib /usr/lib/nvidia, /usr/lib32, etc. Then form full paths from that ancestor and do the blits, while preserving the above "nuke if exists" logic.

That should simplify the code and cover all of the uses, right? And keep the copy list simpler by implicitly allowing skipping over elements.

Instead of our two hard-coded path lists, we'll form relative paths for all optional elements in the list against common ancestors known for biarch distributions. This builds upon the previous work and allows us to replace or grab files from the subdirectories, and also allows the private NVIDIA libraries to exist either within the toplevel libdir or within a private directory, as seen on Fedora. The flow is changed slightly so that our first primary call for each libdir is the only mount, and then we follow up with a simple populate call for the libdir. Signed-off-by: Ikey Doherty <[email protected]>

ikeydoherty · 2018-01-30T11:51:27Z

OK I added a follow up commit which should just make stuff work for Everyone ™

ikeydoherty · 2018-01-30T11:52:21Z

The only pain point I see (because I don't know how it works on Fedora) is this reliance on /usr/lib and not, say, /usr/lib64. Now, if this is an issue on Fedora (i.e they're distinct directories maybe?) then we can make it a configure time option for the LIBDIR? Or patch just patch that one spot, maybe.

Conan-Kudo · 2018-01-30T12:18:22Z

@ikeydoherty They are distinct directories. /usr/lib is 32-bit, whereas /usr/lib64 is 64-bit.

We could make this a compile-time option if you want, then we can feed in the correct base libdir as a configure option (we already do, it just does nothing with it...).

This will allow each distro to provide the native arch and the alternative lib32 directory without us trying to guess where they go. With this change, we'll only try to mount the alternative 32-bit biarch space if we're a 64-bit build of snapd, otherwise we'd only have the native 32-bit arch to worry about in the first place. Signed-off-by: Ikey Doherty <[email protected]>

Signed-off-by: Neal Gompa <[email protected]>

ikeydoherty · 2018-01-31T08:57:00Z

Yay! Danke ^_^

mvo5 added this to the 2.31 milestone Jan 29, 2018

mvo5 approved these changes Jan 29, 2018

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zyga approved these changes Jan 29, 2018

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zyga requested a review from jdstrand January 29, 2018 15:58

jdstrand approved these changes Jan 29, 2018

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ikeydoherty and others added 2 commits January 30, 2018 17:28

packaging/fedora: Enable support for the NVIDIA proprietary drivers

7f8bc25

Signed-off-by: Neal Gompa <[email protected]>

ikeydoherty force-pushed the glvnd-340 branch from 3701eb7 to 7f8bc25 Compare January 30, 2018 18:12

zyga merged commit 14b7841 into canonical:master Jan 31, 2018

jwillikers mentioned this pull request Apr 30, 2024

Consider using libglvnd from Conan instead of the system's via opengl/system conan-io/conan-center-index#23649

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snap-confine/nvidia: Support legacy biarch trees for GLVND systems #4559

snap-confine/nvidia: Support legacy biarch trees for GLVND systems #4559

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snap-confine/nvidia: Support legacy biarch trees for GLVND systems #4559

snap-confine/nvidia: Support legacy biarch trees for GLVND systems #4559

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