webui-desktop: redirect browser stdout/stderr to a log file

[rvykydal]

The browser process inherits the stdout pipe from webui-desktop back
to anaconda's proc.communicate(). When exitGui() kills webui-desktop,
the cleanup trap kills the browser, but Firefox may survive (it forks
into its own process group). While Firefox is alive it holds the pipe
open, so proc.communicate() never returns, anaconda never exits, and
the atexit handler that calls systemctl reboot is never reached.

Redirect the browser's stdout/stderr to webui-browser.log file so that
even if Firefox outlives webui-desktop, it cannot block anaconda's pipe.

[gemini-code-assist]

Code Review

This pull request modifies the webui-desktop script to redirect standard output and error to /dev/null when launching the browser, preventing potential pipe blocking issues. Review feedback highlights that the HOME environment variable is currently lost because pkexec clears the environment; suggestions were made to explicitly pass HOME within the command execution to ensure the browser correctly uses the isolated temporary directory.

[gemini-code-assist]

While the redirection to /dev/null correctly addresses the pipe blocking issue, there is a pre-existing bug in how the environment is passed to pkexec. pkexec clears the environment and sets HOME to the target user's default home directory, which means the isolation intended by the temporary directory created at line 214 is lost. To ensure the browser uses the correct home directory, HOME="$BROWSER_HOME" should be explicitly passed as an argument to the env command. Note that it should be placed after "${user_environment[@]}" to avoid being overwritten if that array contains a HOME entry.

Suggested change

	pkexec --user "$INSTALLER_USER" env XDG_CURRENT_DESKTOP=GNOME "${user_environment[@]}" "${BROWSER[@]}" "$WEBUI_URL" \
	>/dev/null 2>&1 &
	pkexec --user "$INSTALLER_USER" env XDG_CURRENT_DESKTOP=GNOME "${user_environment[@]}" HOME="$BROWSER_HOME" "${BROWSER[@]}" "$WEBUI_URL" \
	>/dev/null 2>&1 &

[gemini-code-assist]

Similar to the graphical session case, the HOME variable should be explicitly passed to the browser via the env command. Since pkexec clears the environment, the HOME="$BROWSER_HOME" assignment at line 238 does not reach the browser process, defeating the isolation provided by the temporary home directory.

Suggested change

	dbus-run-session -- "${BROWSER[@]}" "$WEBUI_URL" \
	>/dev/null 2>&1 &
	HOME="$BROWSER_HOME" \
	dbus-run-session -- "${BROWSER[@]}" "$WEBUI_URL" \
	>/dev/null 2>&1 &

[sourcery-ai]

Hey - I've reviewed your changes and they look great!

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[adamkankovsky]

I'm just wondering if it might be better to redirect these logs to some other log file rather than discarding them entirely, for example, for future debugging.

[KKoukiou]

If it's tested and it works it looks reasonable.

[rvykydal]

If it's tested and it works it looks reasonable.

Yes, tested to be working.

[rvykydal]

I'm just wondering if it might be better to redirect these logs to some other log file rather than discarding them entirely, for example, for future debugging.

Good point, updated.

[rvykydal]

I updated the PR actually limiting the redirection to the boot.iso case (the Live ISO is not using proc.communicate code path)

[adamkankovsky]

Now it looks great, and if it works, I have no objection to it

[rvykydal]

Yes, it works.

FYI The contents of the webui-browser.log from my test run:

[anaconda root@ibm-p8-kvm-03-guest-02 ~]# cat /tmp/webui-browser.log.
restorecon: SELinux: Could not get canonical path for /tmp/install-user/.config/mozilla/firefox/*/gmp-widevinecdm/* restorecon: No such file or directory.
/run/user/1001/anaconda/firefox-profile/user.js:22: prefs parse error: unexpected character
dbus-daemon[3271]: [session uid=1001 pid=3271 pidfd=5] Activating service name='org.a11y.Bus' requested by ':1.0' (uid=1001 pid=3272 comm="/usr/lib64/firefox/firefox --new-instance --profil" labe
l="system_u:system_r:kernel_t:s0")
dbus-daemon[3271]: [session uid=1001 pid=3271 pidfd=5] Successfully activated service 'org.a11y.Bus'
Safe Browsing server returned a 400 during update:request url = https://safebrowsing.googleapis.com/v5/hashLists:batchGet?key=AIzaSyBPGXa4AYD4FC3HJK7LnIKxm4fDusVuuco, payload =.
dbus-daemon[3271]: [session uid=1001 pid=3271 pidfd=5] Reloaded configuration
dbus-daemon[3271]: [session uid=1001 pid=3271 pidfd=5] Reloaded configuration
dbus-daemon[3271]: [session uid=1001 pid=3271 pidfd=5] Reloaded configuration
dbus-daemon[3271]: [session uid=1001 pid=3271 pidfd=5] Reloaded configuration
dbus-daemon[3271]: [session uid=1001 pid=3271 pidfd=5] Reloaded configuration