Building snapd on clearlinux

snapd
1

Hi guys,

I’m tried to build snapd and snap on clearlinux. After building I had a problem with running snap apps. I can successfully install any app, but when I try to run something, I always get an error:

execv failed: No such file or directory

When I built snapd from sources I used next commands:

  1. ./mkversion.sh
  2. cd cmd
  3. autoreconf -i -f
  4. ./configure --enable-merged-usr --disable-apparmor --enable-nvidia-biarch --prefix=/usr --libexecdir=/usr/lib/snapd
  5. make hack

For building snap and snapd binaries I use next commands:

  1. go build -o /usr/lib/snap github.com/snapcore/snapd/cmd/snap
  2. go build -o /usr/lib/snapd github.com/snapcore/snapd/cmd/snapd

And finally I run make install command from snapd/data folder.

Could you please help me to determine why I can install any app but can’t run them. Where is my mistake?

P.s. Sorry for my bad English

2

Can you clarify, what command produces this? Did you try running snap run <name-of-snap>? If so, can you try:

SNAPD_DEBUG=1 SNAP_CONFINE_DEBUG=1 snap run <name-of-snap>
3

Yep, I used snap run <name-of-snap>.

For this command SNAPD_DEBUG=1 SNAP_CONFINE_DEBUG=1 snap run <name-of-snap> I got next output:

2020/10/26 19:03:55.110260 tool_linux.go:68: DEBUG: re-exec not supported on distro “clear-linux-os” yet error: cannot find current revision for snap run: readlink /snap/run/current: no such file or directory

4

This error message indicates that it thinks the name of the snap you are trying to run is verbatim “run”, did you use run as the name of the snap ? Try

snap install hello-world
SNAPD_DEBUG=1 SNAP_CONFINE_DEBUG=1 snap run hello-world
5

Yep, sorry in previous message I had a mistake.

It’s work for hello-world application. I see ‘Hello World!’ in terminal.

But don’t work for code(Visual Studio Code) app or for slack app.

For example:

snap install code --classic SNAPD_DEBUG=1 SNAP_CONFINE_DEBUG=1 snap run code

Output:

2020/10/26 19:14:41.650212 tool_linux.go:68: DEBUG: re-exec not supported on distro “clear-linux-os” yet 2020/10/26 19:14:41.655121 cmd_run.go:404: DEBUG: SELinux not enabled DEBUG: umask reset, old umask was 022 DEBUG: security tag: snap.code.code DEBUG: executable: /usr/lib/snapd/snap-exec DEBUG: confinement: classic DEBUG: base snap: core DEBUG: ruid: 1000, euid: 0, suid: 0 DEBUG: rgid: 1000, egid: 1000, sgid: 1000 DEBUG: preparing classic execution environment DEBUG: set_effective_identity uid:1000 (change: yes), gid:1000 (change: yes) DEBUG: creating user data directory: /home/pi/snap/code/48 DEBUG: ruid: 1000, euid: 1000, suid: 0 DEBUG: setting capabilities bounding set DEBUG: regaining SYS_ADMIN DEBUG: loading bpf program for security tag snap.code.code DEBUG: read 14 bytes from /var/lib/snapd/seccomp/bpf//snap.code.code.bin DEBUG: clearing SYS_ADMIN DEBUG: execv(/usr/lib/snapd/snap-exec, /usr/lib/snapd/snap-exec…) DEBUG: argv[1] = code DEBUG: umask restored to 022 DEBUG: working directory restored to /usr/lib/snapd execv failed: No such file or directory

6

I think you should not “make hack” but look at the installation process of snapd. This is clearly a missing executable.

1 Like
7

What is ldd /usr/lib/snapd/snap-exec ? It might be the case that strict snaps work because the step that is failing for classic snaps is executing snap-exec, which for a strict snap will transition to an environment where snap-exec has the necessary dependencies provided by the base snap, but on the host these do not exist. This may indicate a linking error when building snap-exec for example

8

Output for this command:

ldd: /usr/lib/snapd/snap-exec: No such file or directory.

I don’t have this binary at all.

Now I can run any app, after building snap-exec binary.

Thank you guys for the help.

9

Hi guys,

I need help with one more thing. Right now all --classic apps and hello app is perfectly worked for me, but some apps like chromium, brave, snap-store(and maybe something else) still can’t start.

This is one example of log when I try to load brave browser:

2020/10/30 08:05:20.633460 tool_linux.go:68: DEBUG: re-exec not supported on distro “clear-linux-os” yet 2020/10/30 08:05:20.636955 cmd_run.go:404: DEBUG: SELinux not enabled DEBUG: umask reset, old umask was 022 DEBUG: security tag: snap.brave.brave DEBUG: executable: /usr/lib/snapd/snap-exec DEBUG: confinement: non-classic DEBUG: base snap: core DEBUG: ruid: 1000, euid: 0, suid: 0 DEBUG: rgid: 1000, egid: 1000, sgid: 1000 DEBUG: creating lock directory /run/snapd/lock (if missing) DEBUG: set_effective_identity uid:0 (change: no), gid:0 (change: yes) DEBUG: opening lock directory /run/snapd/lock DEBUG: set_effective_identity uid:0 (change: no), gid:1000 (change: yes) DEBUG: opening lock file: /run/snapd/lock/.lock DEBUG: set_effective_identity uid:0 (change: no), gid:0 (change: yes) DEBUG: set_effective_identity uid:0 (change: no), gid:1000 (change: yes) DEBUG: sanity timeout initialized and set for 30 seconds DEBUG: acquiring exclusive lock (scope (global), uid 0) DEBUG: sanity timeout reset and disabled DEBUG: ensuring that snap mount directory is shared DEBUG: unsharing snap namespace directory DEBUG: set_effective_identity uid:0 (change: no), gid:0 (change: yes) DEBUG: set_effective_identity uid:0 (change: no), gid:1000 (change: yes) DEBUG: releasing lock 5 DEBUG: opened snap-update-ns executable as file descriptor 5 DEBUG: opened snap-discard-ns executable as file descriptor 6 DEBUG: creating lock directory /run/snapd/lock (if missing) DEBUG: set_effective_identity uid:0 (change: no), gid:0 (change: yes) DEBUG: opening lock directory /run/snapd/lock DEBUG: set_effective_identity uid:0 (change: no), gid:1000 (change: yes) DEBUG: opening lock file: /run/snapd/lock/brave.lock DEBUG: set_effective_identity uid:0 (change: no), gid:0 (change: yes) DEBUG: set_effective_identity uid:0 (change: no), gid:1000 (change: yes) DEBUG: sanity timeout initialized and set for 30 seconds DEBUG: acquiring exclusive lock (scope brave, uid 0) DEBUG: sanity timeout reset and disabled DEBUG: initializing mount namespace: brave DEBUG: snappy_udev_init DEBUG: setup_devices_cgroup DEBUG: set_effective_identity uid:0 (change: no), gid:0 (change: yes) DEBUG: set_effective_identity uid:0 (change: no), gid:1000 (change: yes) DEBUG: write_string_to_file /sys/fs/cgroup/devices/snap.brave.brave/cgroup.procs 7127 DEBUG: write_string_to_file /sys/fs/cgroup/devices/snap.brave.brave/devices.deny a DEBUG: running snap-device-helper add snap_brave_brave /sys/class/mem/null 1:3 execl failed: No such file or directory child exited with status 1: File exists

I appreciate any help to figure out this problem.

10

Fixed problem with coping snap-device-helper file from sources to /usr/lib/snapd folder.

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