🏁 Script executed:

find . -name "docker-compose-library.yaml" -o -name "*compose*.yaml" | head -20

Repository: lightspeed-core/lightspeed-stack

Length of output: 127

🏁 Script executed:

sed -n '60,80p' ./docker-compose-library.yaml

Repository: lightspeed-core/lightspeed-stack

Length of output: 1078

🌐 Web query:

bash PID1 signal handling Docker entrypoint

💡 Result:

When your Docker container’s PID 1 is bash (or /bin/sh -c), signal handling often surprises you:

• PID 1 is special in Linux namespaces: if PID 1 doesn’t install handlers, some signals (notably SIGTERM/SIGINT) won’t have their normal “default action” of terminating the process. So docker stop may hang until Docker sends SIGKILL. [1]
• If you use shell-form CMD/ENTRYPOINT (string form), Docker effectively runs your command under /bin/sh -c, and signals may not reach your real app (your app isn’t PID 1). Docker explicitly warns that shell-form ENTRYPOINT “does not pass signals”. [2]

Best practices for Docker entrypoints

1. Prefer exec-form ENTRYPOINT / CMD (JSON array)

ENTRYPOINT ["/usr/local/bin/my-app"]
# or
CMD ["/usr/local/bin/my-app"]

This avoids /bin/sh -c wrappers and lets your app receive signals directly. [2]

2. If you must use a shell script entrypoint, exec the long-running process

#!/bin/sh
set -e
# setup...
exec my-app "$@"

This replaces the shell with your app, so the app becomes PID 1 and receives SIGTERM. Docker’s own docs call out using exec for clean docker stop behavior. [2]

3. Use a minimal init as PID 1 (recommended): --init (tini) or bake it in

• Docker CLI: docker run --init … makes an init process run as PID 1 (backed by tini) and handle duties like signal forwarding and zombie reaping. [3]
• Or explicitly: ENTRYPOINT ["tini","--","/your/entrypoint.sh"] (tini docs). [4]

Most common fix: switch to exec-form + ensure your entrypoint script ends with exec …, or run with --init.

Sources:
[1] Docker run reference (PID 1 signal behavior) https://www.docs4dev.com/docs/docker/19.03/engine/reference/run/
[2] Dockerfile reference (shell vs exec form; shell form doesn’t pass signals; use exec) https://docs.docker.com/reference/builder
[3] docker container run docs (--init, docker-init backed by tini) https://docs.docker.com/reference/cli/docker/container/run
[4] tini README (--init and usage) https://github.com/krallin/tini

🌐 Web query:

umask 077 file permissions /tmp default permissions bash

💡 Result:

• umask 077 affects new files/directories your process creates anywhere, including under /tmp. It removes all group/other permissions from the requested mode. (sans.org)

  • Typical result:
    • New files: 0666 & ~0077 = 0600 (rw-------)
    • New directories: 0777 & ~0077 = 0700 (rwx------) (sans.org)

• /tmp itself is normally world-writable with the sticky bit: mode 1777 (drwxrwxrwt). Your umask does not change /tmp’s existing permissions; it only affects what you create inside it. (linuxconfig.org)

• Bash is not special here: if you set umask 077 in your shell (or in ~/.bashrc, etc.), then commands you run from that shell inherit it and will create /tmp files accordingly (unless the program explicitly chmods after creation or requests a more restrictive mode). (bs2manuals.ts.fujitsu.com)

• Many systems ensure /tmp has mode 1777 at boot via systemd-tmpfiles rules (example entries show 1777 directories under /tmp). (freedesktop.org)

Citations:

• 1: https://www.sans.org/blog/understanding-user-permissions-your-first-line-of-defense-part-3-of-5/?utm_source=openai
• 2: https://www.sans.org/blog/understanding-user-permissions-your-first-line-of-defense-part-3-of-5/?utm_source=openai
• 3: https://linuxconfig.org/explaining-the-sticky-bit-what-the-t-in-linux-directory-permissions-means?utm_source=openai
• 4: https://bs2manuals.ts.fujitsu.com/psPOSIXV210en/umask-get-or-set-the-file-mode-creation-mask-posix-commands-2025-09-215-13638739.html?utm_source=openai
• 5: https://www.freedesktop.org/software/systemd/man/tmpfiles.d.html?utm_source=openai

🌐 Web query:

docker-compose entrypoint exec umask syntax YAML multiline string

💡 Result:

Use exec-form (entrypoint: as a YAML list) and run a shell explicitly so you can set umask and then exec the real process (so it becomes PID 1 and receives signals). Compose allows entrypoint as either a string or a list; the list form is the “Dockerfile-like”/exec style. [1]

services:
  app:
    image: your-image
    entrypoint:
      - /bin/sh
      - -c
      - |
          umask 002
          exec "$@"
      - --
    command: ["your-binary", "arg1", "arg2"]

Notes:

• | is just YAML “multiline string”; it becomes the single script argument to sh -c (newlines included).
• The -- is used as the $0 placeholder for sh -c; then command: becomes $@, which exec "$@" runs.
• Using exec ... ensures the final process is PID 1 (important for signal handling), as recommended in Docker’s ENTRYPOINT docs. [2]

Sources: Docker Compose entrypoint reference [1]; Docker ENTRYPOINT shell vs exec form + exec for proper PID 1 behavior [2].

[1] (docs.docker.com)
[2] (docs.docker.com)

Citations:

• 1: https://docs.docker.com/reference/compose-file/services/?utm_source=openai
• 2: https://docs.docker.com/reference/dockerfile/?utm_source=openai

🏁 Script executed:

cat -n docker-compose.yaml | sed -n '85,95p'

Repository: lightspeed-core/lightspeed-stack

Length of output: 519

🌐 Web query:

bash PID1 signal handling swallow signals docker

💡 Result:

When you run a shell script as the container “main process”, bash becomes PID 1, and PID 1 has special signal semantics in Linux containers:

• PID 1 doesn’t get the normal “default action” for many fatal signals (like SIGTERM): if PID 1 hasn’t installed a handler, the signal may effectively do nothing, so docker stop (SIGTERM) appears “swallowed”. This is why containers can linger until Docker eventually sends SIGKILL. [1], [2]
• Even if bash traps/exits on SIGTERM, it typically won’t forward that signal to its child process(es) unless you explicitly do so—so your actual app keeps running. [3]

What to do instead (common fixes)

1. Prefer making your app PID 1 (avoid bash as PID 1)
   Use Docker “exec form” so your process replaces the shell (no extra PID 1 shell layer). (This avoids the “shell doesn’t forward signals” problem.) [3]

2. Add a minimal init as PID 1 (recommended for general robustness)
   Run with Docker’s built-in init (tini) so signals are forwarded and zombies are reaped: docker run --init … (or init: true in Compose). [4]

3. If you must use bash as PID 1: trap + forward signals
   At minimum, install a SIGTERM trap (so PID 1 actually exits) and explicitly propagate termination to the child process group (otherwise children may ignore it). The need to trap TERM as PID 1 is the key point. [3]

Sources:
[1] https://stackoverflow.com/questions/71448484/why-does-foreground-job-ignore-job-control-signals-when-bash-is-running-as-pid-1
[2] https://semisignal.com/sigterm-and-pid1/
[3] https://cloud.theodo.com/en/blog/docker-processes-container
[4] https://raby.sh/sigterm-and-pid-1-why-does-a-container-linger-after-receiving-a-sigterm.html

🌐 Web query:

/tmp file permissions default linux umask security

💡 Result:

• Default /tmp directory permissions on most Linux distros are drwxrwxrwt (octal 1777) owned by root:root: world-writable with the sticky bit so users can’t delete/rename other users’ files in /tmp even though everyone can create files there. This is commonly enforced at boot by systemd-tmpfiles rules (often D /tmp 1777 root root -). [1] [2]

• umask controls the default permissions of new files/dirs created inside /tmp (it does not change /tmp’s own 1777 mode). When a program creates a file, the kernel applies:
  final_mode = requested_mode & ~umask (and similarly for directories). Typical default umask is 022, so a file created with requested mode 0666 becomes 0644. [3]

• Security implications / best practice

  • /tmp is a shared namespace: predictable names like /tmp/foo can be pre-created by another user to cause failures or trick a program (DoS, symlink/hardlink-style attacks). Use unique, non-guessable names and safe creation patterns (e.g., “create-new” semantics), and prefer honoring $TMPDIR when set. [4]
  • The sticky bit does not prevent reads. If your program creates temp files with permissive modes (because it requests 0666 and relies on umask), other users may read them. Set sensitive temp files to owner-only permissions explicitly (and don’t rely on umask alone). [3]
  • For services, consider systemd PrivateTmp=yes to give the service its own private /tmp (and /var/tmp) namespace, reducing cross-process attacks via shared temp directories. [5]

• Persistence note (/tmp vs /var/tmp)

  • /tmp is often cleared at boot and may be on tmpfs (RAM/swap), while /var/tmp is generally more persistent and intended to survive reboots. [6] [4]

Sources:
[1] https://www.baeldung.com/linux/sticky-bit
[2] https://www.freedesktop.org/software/systemd/man/tmpfiles.d.html
[3] https://manpages.debian.org/testing/manpages-dev/umask.2.en.html
[4] https://systemd.io/TEMPORARY_DIRECTORIES/
[5] https://www.redhat.com/de/blog/new-red-hat-enterprise-linux-7-security-feature-privatetmp
[6] https://unix.stackexchange.com/questions/30489/what-is-the-difference-between-tmp-and-var-tmp

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