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bashshellunixadb

"How to run a single command as a background process using su -c

Running by hand,

adb shell
su
chmod 666 /dev/graphics/fb0
export CLASSPATH=/data/local/device.jar
export LD_LIBRARY_PATH=/data/local
exec app_process /system/bin com.device.client.Main /data/local/device.conf &

Performs as expected.

However, trying to run this from a bash script using the following command does not work as expected.

adb shell "su -c '
chmod 666 /dev/graphics/fb0
&& export CLASSPATH=/data/local/device.jar
&& export LD_LIBRARY_PATH=/data/local
&& exec app_process /system/bin com.device.client.Main /data/local/device.conf &'"

It works without &, but with & it just won't start the binary. exec app_process has to be a background process.

It's possible that the shell executes the binary but then just dies, because it does not wait on anything else, but I don't know how to fix it. Making su a background process should do it, '&" but it didn't work.

When running without &, we get:

D/su ( 1728): 0 /system/bin/sh executing 0 
D/su ( 1728): chmod 666 /dev/graphics/fb0
D/su ( 1728): && export CLASSPATH=/data/local/device.jar
D/su ( 1728): && export LD_LIBRARY_PATH=/data/local
D/su ( 1728): && exec app_process /system/bin com.device.client.Main /data/local/device.conf using shell /system/bin/sh : sh

When adding &, we get:

D/su ( 1746): 0 /system/bin/sh executing 0 
D/su ( 1746): chmod 666 /dev/graphics/fb0
D/su ( 1746): && export CLASSPATH=/data/local/device.jar
D/su ( 1746): && export LD_LIBRARY_PATH=/data/local
D/su ( 1746): && exec app_process /system/bin com.device.client.Main /data/local/device.conf & using shell /system/bin/sh : sh

but nothing gets loaded!

How can I run my set of commands, ensuring that app_process will run in the background?

Solution

  • I don't have adb (its an old debugger right) but a good syntax for passing a set of commands to the su command is:

    su -c bash <<END_BASH
chmod 666 /dev/graphics/fb0
export CLASSPATH=/data/local/device.jar
export LD_LIBRARY_PATH=/data/local
exec app_process /system/bin com.device.client.Main /data/local/device.conf &
END_BASH