restore gosu suid bit when container stops

[kaluzki]

#226

thanks to these guys:

• https://stackoverflow.com/questions/41451159/how-to-execute-a-script-when-i-terminate-a-docker-container
• https://hynek.me/articles/docker-signals/

cd docker
docker build -t webdevops/base base/alpine

# interactive -> strg+c

docker run --name bug226 -ti --user 1000 webdevops/base
-> Executing /opt/docker/provision/entrypoint.d/05-gosu.sh
-> Executing /opt/docker/provision/entrypoint.d/05-permissions.sh
-> Executing /opt/docker/bin/service.d/supervisor.d//10-init.sh
2019-12-01 17:10:00,860 INFO Included extra file "/opt/docker/etc/supervisor.d/cron.conf" during parsing
2019-12-01 17:10:00,860 INFO Included extra file "/opt/docker/etc/supervisor.d/dnsmasq.conf" during parsing
2019-12-01 17:10:00,860 INFO Included extra file "/opt/docker/etc/supervisor.d/postfix.conf" during parsing
2019-12-01 17:10:00,860 INFO Included extra file "/opt/docker/etc/supervisor.d/ssh.conf" during parsing
2019-12-01 17:10:00,860 INFO Included extra file "/opt/docker/etc/supervisor.d/syslog.conf" during parsing
2019-12-01 17:10:00,860 INFO Set uid to user 0 succeeded
2019-12-01 17:10:00,868 INFO RPC interface 'supervisor' initialized
2019-12-01 17:10:00,868 INFO supervisord started with pid 19
^C
2019-12-01 17:10:17,702 WARN received SIGINT indicating exit request
Container stopped, performing teardown...
-> Executing /opt/docker/provision/entrypoint.d/teardown/05-gosu.sh

docker start bug226
docker logs bug226
...
-> Executing /opt/docker/provision/entrypoint.d/05-gosu.sh
-> Executing /opt/docker/provision/entrypoint.d/05-permissions.sh
-> Executing /opt/docker/bin/service.d/supervisor.d//10-init.sh
2019-12-01 17:11:43,870 INFO Included extra file "/opt/docker/etc/supervisor.d/cron.conf" during parsing
2019-12-01 17:11:43,870 INFO Included extra file "/opt/docker/etc/supervisor.d/dnsmasq.conf" during parsing
2019-12-01 17:11:43,870 INFO Included extra file "/opt/docker/etc/supervisor.d/postfix.conf" during parsing
2019-12-01 17:11:43,870 INFO Included extra file "/opt/docker/etc/supervisor.d/ssh.conf" during parsing
2019-12-01 17:11:43,870 INFO Included extra file "/opt/docker/etc/supervisor.d/syslog.conf" during parsing
2019-12-01 17:11:43,870 INFO Set uid to user 0 succeeded
2019-12-01 17:11:43,878 INFO RPC interface 'supervisor' initialized
2019-12-01 17:11:43,878 INFO supervisord started with pid 17

docker exec -ti bug226 whoami
whoami: unknown uid 1000



docker stop bug226 
docker rm bug226



# daemon

docker run --name bug226 -d --user 1000 webdevops/base
...
docker logs bug226
-> Executing /opt/docker/provision/entrypoint.d/05-gosu.sh
-> Executing /opt/docker/provision/entrypoint.d/05-permissions.sh
-> Executing /opt/docker/bin/service.d/supervisor.d//10-init.sh
2019-12-01 17:15:40,460 INFO Included extra file "/opt/docker/etc/supervisor.d/cron.conf" during parsing
2019-12-01 17:15:40,460 INFO Included extra file "/opt/docker/etc/supervisor.d/dnsmasq.conf" during parsing
2019-12-01 17:15:40,460 INFO Included extra file "/opt/docker/etc/supervisor.d/postfix.conf" during parsing
2019-12-01 17:15:40,460 INFO Included extra file "/opt/docker/etc/supervisor.d/ssh.conf" during parsing
2019-12-01 17:15:40,460 INFO Included extra file "/opt/docker/etc/supervisor.d/syslog.conf" during parsing
2019-12-01 17:15:40,460 INFO Set uid to user 0 succeeded
2019-12-01 17:15:40,468 INFO RPC interface 'supervisor' initialized
2019-12-01 17:15:40,468 INFO supervisord started with pid 17

docker stop bug226
docker logs bug226
...
Container stopped, performing teardown...
-> Executing /opt/docker/provision/entrypoint.d/teardown/05-gosu.sh

docker start bug226
docker logs bug226
...
-> Executing /opt/docker/provision/entrypoint.d/05-gosu.sh
-> Executing /opt/docker/provision/entrypoint.d/05-permissions.sh
-> Executing /opt/docker/bin/service.d/supervisor.d//10-init.sh
2019-12-01 17:17:39,927 INFO Included extra file "/opt/docker/etc/supervisor.d/cron.conf" during parsing
2019-12-01 17:17:39,927 INFO Included extra file "/opt/docker/etc/supervisor.d/dnsmasq.conf" during parsing
2019-12-01 17:17:39,927 INFO Included extra file "/opt/docker/etc/supervisor.d/postfix.conf" during parsing
2019-12-01 17:17:39,927 INFO Included extra file "/opt/docker/etc/supervisor.d/ssh.conf" during parsing
2019-12-01 17:17:39,927 INFO Included extra file "/opt/docker/etc/supervisor.d/syslog.conf" during parsing
2019-12-01 17:17:39,927 INFO Set uid to user 0 succeeded
Unlinking stale socket /.supervisor.sock
2019-12-01 17:17:40,261 INFO RPC interface 'supervisor' initialized
2019-12-01 17:17:40,261 INFO supervisord started with pid 19

docker exec -ti bug226 whoami
whoami: unknown uid 1000

[htuscher]

You must hand over the first argument given by the general entrypoint.sh script.
The entrypoint system is constructed to have alternative services instead of supervisord to run.
By omitting that argument that becomes impossible and will break many setups.

[kaluzki]

im not very experienced in bash, and was a little bit confused by the fact that
the function runEntrypoints doesn't expect any argument and also doesn't provide it
explicitely to its task scripts. so i assumed the parameter handling in the task doesn't
work anyway. but now i just tried some scripts and was very suprised :)

[htuscher]

Yes, the "$@" is basically a ... in other programming languages

[htuscher]

@kaluzki Unfortunately I had to revert the merge, because a very widely usage to get an interactive shell doesn't work anymore with this solution:

docker run --rm -ti --user 1000 webdevops/php:7.3 bash
Container stopped, performing teardown...
-> Executing /opt/docker/provision/entrypoint.d/teardown/05-gosu.sh

Expected:

docker run --rm -ti --user 1000 webdevops/php:7.3 bash
root@ca4f47973adb:/#

I've backuped the merged result in the branch merge_trap. If you find a solution it would be great.

Thx for contributing