If `--tty` is not passed to `docker exec` because stdout is not available (`[ ! -t 1 ]`), like due to redirection to file (`&> build.log`) or if stdin is not available (`< /dev/null`), then docker does not forward kill signals to the process started and they remain running.
To fix the issue, the `DOCKER_EXEC_PID_FILE_PATH` env variable with the value `/tmp/docker-exec-pid-<timestamp>` is passed to the process called with `docke exec` and the process started stores its pid in the file path passed. Traps are set in `run-docker.sh` that runs the `docker exec` command to receive any kills signals, and if it does, it runs another `docker exec` command to read the pid of the process previously started from `DOCKER_EXEC_PID_FILE_PATH` and then kills it and all its children.
See Also:
https://github.com/docker/cli/issues/2607https://github.com/moby/moby/issues/9098https://github.com/moby/moby/pull/41548https://stackoverflow.com/questions/41097652/how-to-fix-ctrlc-inside-a-docker-container
Also passing `--init` to `docker run` to "Run an init inside the container that forwards signals and reaps processes", although it does not work for above cases, but may helpful in others. The `--init` flag changes will only engage on new container creation.
https://docs.docker.com/engine/reference/run/#specify-an-init-processhttps://docs.docker.com/engine/reference/commandline/run/
```
./scripts/run-docker.sh ./build-package.sh -f libjpeg-turbo &> build.log
^C
$ ./scripts/run-docker.sh ps -efww
Running container 'termux-package-builder' from image 'termux/package-builder'...
UID PID PPID C STIME TTY TIME CMD
builder 1 0 0 05:48 pts/0 00:00:00 bash
builder 9243 0 0 06:01 pts/1 00:00:00 bash
builder 28127 0 0 06:12 ? 00:00:00 /bin/bash ./build-package.sh -f libjpeg-turbo
builder 28141 28127 0 06:12 ? 00:00:00 /bin/bash ./build-package.sh -f libjpeg-turbo
builder 28449 28141 1 06:12 ? 00:00:00 ninja -w dupbuild=warn -j 8
builder 28656 28449 0 06:12 ? 00:00:00 /bin/sh -c /home/builder/.termux-build/_cache/android-r23c-api-24-v0/bin/clang
builder 28657 28656 79 06:12 ? 00:00:01 /home/builder/.termux-build/_cache/android-r23c-api-24-v0/bin/clang
builder 28694 28449 0 06:12 ? 00:00:00 /bin/sh -c /home/builder/.termux-build/_cache/android-r23c-api-24-v0/bin/clang
builder 28695 28694 89 06:12 ? 00:00:00 /home/builder/.termux-build/_cache/android-r23c-api-24-v0/bin/clang
builder 28728 28449 0 06:12 ? 00:00:00 /bin/sh -c /home/builder/.termux-build/_cache/android-r23c-api-24-v0/bin/clang
builder 28729 28728 0 06:12 ? 00:00:00 /home/builder/.termux-build/_cache/android-r23c-api-24-v0/bin/clang
builder 28731 28449 0 06:12 ? 00:00:00 /bin/sh -c /home/builder/.termux-build/_cache/android-r23c-api-24-v0/bin/clang
builder 28734 28731 0 06:12 ? 00:00:00 /home/builder/.termux-build/_cache/android-r23c-api-24-v0/bin/clang
builder 28740 28449 0 06:12 ? 00:00:00 /bin/sh -c /home/builder/.termux-build/_cache/android-r23c-api-24-v0/bin/clang
builder 28741 28740 0 06:12 ? 00:00:00 /home/builder/.termux-build/_cache/android-r23c-api-24-v0/bin/clang
builder 28744 0 0 06:12 pts/2 00:00:00 ps -efww
builder 28748 28449 0 06:12 ? 00:00:00 /bin/sh -c /home/builder/.termux-build/_cache/android-r23c-api-24-v0/bin/clang
builder 28752 28748 0 06:12 ? 00:00:00 /home/builder/.termux-build/_cache/android-r23c-api-24-v0/bin/clang
builder 28753 28449 0 06:12 ? 00:00:00 /bin/sh -c /home/builder/.termux-build/_cache/android-r23c-api-24-v0/bin/clang
builder 28754 28753 0 06:12 ? 00:00:00 /home/builder/.termux-build/_cache/android-r23c-api-24-v0/bin/clang
builder 28755 28449 0 06:12 ? 00:00:00 ninja -w dupbuild=warn -j 8
$ ./scripts/run-docker.sh ./build-package.sh -f libjpeg-turbo &> build.log
$ ./scripts/run-docker.sh ./build-package.sh -f libjpeg-turbo
Running container 'termux-package-builder' from image 'termux/package-builder'...
ERROR: Another build is already running within same environment.
```
Will run "sudo ethtool -K eth0 tx off rx off" in container before executing
build commands.
Since our build environment doesn't have ethtool installed, this will
imply rebuilding Docker image. Until that, CI builds will fail due to
missing utility.
By defining CONTAINER_NAME one can now build from multiple containers:
CONTAINER_NAME=builder1 ./scripts/run-docker.sh
CONTAINER_NAME=builder2 ./scripts/run-docker.sh
...
