Why Not pkexec?

[johnywhy]

hi, why does root thunar launcher use
/opt/porteus-scripts/xorg/psu "dbus-launch --exit-with-session thunar %F"

instead of
pkexec thunar

?

THX

[ncmprhnsbl]

that command, which actually needs to be gksu -l dbus-launch --exit-with-session thunar %F (pending bugfix) (note: in xfce(and others) /opt/porteus-scripts/xorg/psu is a symlink to /usr/bin/gksu )
is mainly to remove unwanted (system)mount entries in thunars' sidebar (some gvfs issue i think)
my own experiments with pkexec seemed to suggest that it doesn't take extra arguments (ie dbus-launch --exit-with-session)

[johnywhy]

i just changed the built-in Thunar (root) launcher to your command
gksu -l dbus-launch --exit-with-session thunar %F

and now it fails.
it works with default command.

THX

[ncmprhnsbl]

yeah, sorry, that should have quotes: gksu -l "dbus-launch --exit-with-session thunar %F"
the -l option(login shell) fixes some issue affecting child processes if remember correctly...

[johnywhy]

why not pkexec?

ToZ says it's ok, if org.xfce.thunar.policy contains

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<annotate key="org.freedesktop.policykit.exec.allow_gui">true</annotate>

https://forum.xfce.org/viewtopic.php?pid=49488#p49488

Porteus does. So, pkexec should be ok, no?

THX

[Ed_P]

Why have two commands to do the same thing? Which one is smaller?

[johnywhy]

Why have two commands to do the same thing? Which one is smaller?

exactly. This:

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pkexec thunar

is smaller than

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gksu -l dbus-launch --exit-with-session thunar %F

Functionally, what's the difference?

[brokenman]

I believe ncmprhnsbl already answered this question in his first post.

[johnywhy]

I believe ncmprhnsbl already answered this question in his first post.

Whether i can understand is a separate issue

i think exit-with-session is the sole reason ncmprhnsbl uses dbus-launch. Correct?
-l is the sole reason ncmprhnsbl uses gksu, correct?

gksu man says

--login, -l
Make this a login shell. Beware this may cause problems with the Xauthority magic. Run xhost to allow the target user to open windows on your display!
https://linux.die.net/man/1/gksu

i'm not sure if they mean run xhost instead, or in addition. Could this cause problems with porteus Xauthority?

Why do we need a login shell? This post says

login shells typically read a file that does things like setting environment variables

I'm taking a wild guess, that this has something to do with the environment variables which we want set to the local user, not root, to avoid the issue of root taking ownership of Thunar config files. Correct?

if we're avoiding pkexec to avoid making a policy file, we can do pkexec without a policy file by putting the environment variables on the command line. https://askubuntu.com/a/332847

so, maybe i should really compare these two. Correct?

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pkexec env DISPLAY=$DISPLAY XAUTHORITY=$XAUTHORITY thunar
gksu -l dbus-launch --exit-with-session thunar %F

freedesktop.org doesn't recommend using ncmprhnsbl's exit-with-session switch

exit-with-session
If this option is provided, a persistent "babysitter" process will be created, as if for --exit-with-x11. If it cannot connect to the X server, it will monitor the terminal from which dbus-launch was started instead, and if it gets a HUP on stdin, the message bus daemon will be killed. This option is not recommended, since it will consume input from the terminal where it was started; it is mainly provided for backwards compatibility.
https://dbus.freedesktop.org/doc/dbus-launch.1.html

So what's their modern alternative to exit-with-session?

btw, is gksu on porteus an alias? On Mint forum, i got pkexec for a gksudo alias:

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echo '/usr/bin/pkexec env DISPLAY=$DISPLAY XAUTHORITY=$XAUTHORITY $@'|sudo tee /usr/local/bin/gksudo
chmod +x /usr/local/bin/gksudo

THX

[ncmprhnsbl]

think exit-with-session is the sole reason ncmprhnsbl uses dbus-launch. Correct?

no, dbus-launch is for dbus-launch "is mainly to remove unwanted (system)mount entries in root thunars' sidebar (some gvfs issue i think)"

So what's their modern alternative to exit-with-session?

if i reading correctly, probably the "--exit-with-x11" because it doesn't "consume input from the terminal where it was started", whatever that means... thanks for pointing that out , i'll look into it..

btw, is gksu on porteus an alias? On Mint forum, i got pkexec for a gksudo alias:

no. gksu is /usr/bin/gksu.

[johnywhy]

thx, can't say i fully understand, but slowly, slowly...