Develop Reference

How to change permission of internal folder/file in android?

I wanted to get database file from the emulator. So, I tried to change the permission of package folder using adb shell. When I use the below command:
adb shell su -c chmod 777 /data/data/com.mypackage.test
It always returns:
Chmod: need 2 arguments
I have changed permission some days ago using above command. But recently I'm always getting the above warning. I have searched a lot and found large information regarding using above command but no one mentioned about this warning issue.

I have overcome this issue instead of running adb shell su -c "chmod 777 /data", I run the adb shell first and then the following command : su -c "chmod 777 /data".

I have overcome this issue ： adb shell su -c 'chmod 777 /data/data/com.mypackage.test'

nohangup using ADB shell

I am trying to do a logcat to a file using adb shell by following command -
adb shell "nohup logcat -f /storage/sdcard0/myLog.txt -v time &"
If I do a ps | grep logcat, I don't see the logcat command. Even I tried to see nohup command, but it is not there. So somehow above command does not work.
However if I perform the command in 2 steps it works fine -
adb shell
nohup logcat -f /storage/sdcard0/myLog.txt -v time &
I can see the process using ps and logcat continues to record to the file even if I disconnect adb shell. Now I would like the first command to work, since I am using python scripts to issue commands via ADB. It is possible to change the python scripts, however I would like to know if I am doing anything wrong in issuing the first command and if it is possible to make it work.

try
adb logcat
not
adb shell logcat

Copying files in ADB shell with run-as

Is there a way to write a script that will copy files from an ADB shell using run-as?
The only way I know of to copy in the adb shell is using cat source > dest (edit: modern android versions have the cp command, which makes this question unnecessary), but I am only able to quote the greater-than sign one level deep - so my script can pass it to adb shell, but not to adb shell run-as.
For example, this works:
adb shell "cat source > dest"
But this does not:
adb shell run-as "cat source > dest"
Nor this:
adb shell "run-as cat source \> dest"
I even tried created a small script and uploading it to the device, but I can't seem to run the script from the adb shell - it tells me "permission denied". I can't chmod the script, either.
The reason I want to do this is to copy a file into an app's private storage area - specifically, I am using a script to modify shared preferences and put the modified preferences back. Only the app itself or root can write to the file I want, however.
The use case in this scenario is coping a file to a protected location on the device, not retrieving it; for retrieving, there are already good answers in this question.

The OP tried to combine the following 3 commands (that he had no problem executing one after another in the interactive shell session) into a single non-interactive command:
adb shell
run-as com.example.app
cat /sdcard/temp_prefs.xml > shared_prefs/com.example.app_preferences.xml
For simplicity let's start from within an interactive adb shell session. If we just try to combine the last two commands into a single line:
run-as com.example.app cat /sdcard/temp_prefs.xml > shared_prefs/com.example.app_preferences.xml
This would not work because of how shell redirection works - only the cat /sdcard/temp_prefs.xml part of the command would be run with com.example.app UID
Many people "know" to put the part of the command around redirection into quotes:
run-as com.example.app "cat /sdcard/temp_prefs.xml > shared_prefs/com.example.app_preferences.xml"
This does not work because the run-as command is not smart enough to parse the whole command. It expects an executable as the next parameter. The proper way to do it would be to use sh instead:
run-as com.example.app sh -c "cat /sdcard/temp_prefs.xml > shared_prefs/com.example.app_preferences.xml"
So can we just prepend adb shell to the command and be done with it? Not necessarily. By running the command from your PC you also add another local shell and its parser. Specific escape requirements would depend on your OS. In Linux or OSX (if your command does not already contain any ') it is easy to single-quote the whole command like so:
adb shell 'run-as com.example.app sh -c "cat /sdcard/temp_prefs.xml > shared_prefs/com.example.app_preferences.xml"'
But sometimes it is just easier to use an alternative solutions with (-out or less) quotes:
adb shell run-as com.example.app cp /sdcard/temp_prefs.xml shared_prefs/com.example.app_preferences.xml
Or if your device does not have the cp command:
adb shell run-as com.example.app dd if=/sdcard/temp_prefs.xml of=shared_prefs/com.example.app_preferences.xml
Also notice how I used shared_prefs/com.example.app_preferences.xml instead of full /data/data/com.example.app/shared_prefs/com.example.app_preferences.xml - normally inside of run-as command your current directory is the HOME dir of your package.

Following Chris Stratton's advice, the way I eventually got this to work was as follows (for copying shared preferences back to the device):
adb push shared_prefs.xml /sdcard/temp_prefs.xml
cat <<EOF | adb shell
run-as com.example.app
cat /sdcard/temp_prefs.xml > /data/data/com.example.app/shared_prefs/com.example.app_preferences.xml
exit
exit
EOF
Piping directly to adb shell run-as did not work, and I do not know why, but piping to adb shell does. The trick is to then call run-as from the interactive shell, and it continues to accept input from the pipe.
The HERE doc lets me easily embed the newlines to separate commands and in general just makes it readable; I did not have much luck with semicolons, but that might have been because of the way I was doing things. I believe it might work with other methods of piping multiple commands/newlines; I stopped the experiment once I finally got it to work.
The two exits are necessary to prevent a hanging shell (killable with CTRL-C); one for run-as, and the other for adb shell itself. Adb's shell doesn't respond to end-of-file very nicely, it seems.

you could just change the permission of the directory and then pull all the files out. but for me i was looking for just one shared preference file and i was able to get the data like this:
PACKAGE='com.mypackage.cool'
SHAREDPREF_FILE="${PACKAGE}_preferences.xml"
adb shell "run-as $PACKAGE cat /data/data/$PACKAGE/shared_prefs/$SHAREDPREF_FILE">$SHAREDPREF_FILE
now we have the data of the sharedpreference file stored in a file of the same name.

Using the latest adb (ADB v1.0.41 / Version 33.0.3) and a Play Store emulator image I experienced adb root not being granted. I also could not copy from /data/local/ or /storage/emulated/0/ due to not having permissions when run-as com.myapp.app
new_prefs_path="my_machine.xml"
config="$(cat $new_prefs_path)"
my_app_uri="com.myapp.app"
adb shell "run-as $my_app_uri sh -c 'echo \"$config\" > shared_prefs/on_android.xml'"
This fixes it for me as a bash script. It's made slightly more complicated by needing to be configurable for different apps and complex payloads.
We take a file (could be generated earlier in this script) and read it to a variable.
We then start shell, do run-as my app and run echo expanding the read file to a file in shared_prefs.

How to start an android app with valgrind

I've been searching for the last week trying to find an answer to this question.
How do I start an Android app with valgrind? I know I can start an app with the 'am' command, but it starts the app and exits.
I'm writing an app that uses the NDK for native C code, and I need to check it for suspected memory errors.
Edit:
I've learned a little more. You can "wrap" an app with a shell script.
Here's the shell script I'm using:
#!/system/bin/sh
VGPARAMS='--error-limit=no'
export TMPDIR=/data/data/com.starlon.froyvisuals
exec /data/local/Inst/bin/valgrind $VGPARAMS $*
And here's setprop:
adb shell setprop wrap.com.starlon.froyvisuals "logwrapper valgrind"
And here's how I start the app:
adb shell am start -n com.starlon.froyvisuals/.FroyVisuals
I don't think this is right, because I'm not sure where the shell script fits in and I'm not seeing anything in logcat. Any hints?
Edit2:
Oh the shell script is indicated with "setprop" command above. So
adb shell setprop wrap.com.starlon.froyvisuals "logwrapper /data/local/val.sh"
I'm still not seeing anything in logcat.

You can try to clear the logcat first
prompt# adb logcat -c
prompt# adb logcat
You should be able to see the logs coming in once you triggered your application.
am start -a android.intent.action.MAIN -n com.example.hellojni/.HelloJni
I had problems with my shell script and i used this instead.
adb shell setprop wrap.com.example.hellojni "logwrapper /data/local/Inst/bin/valgrind"
You should be able to pass in the parameter right after valgrind

I encountered this problem too. In my situation, I edit the "val.sh" in windows & adb push it to the emulator, but the shell script could not be executed correctly. Then I use a echo "*" > val.sh style to make the "val.sh" and It works well.
So you should first make sure the "val.sh" could be interpreted correctly.

Launch a script as root through ADB

I have created a script to mount partitions and do some stuff in my Android system. I saved the script as install.sh in the /bin folder of Android.
I want to call the script from ADB, which is itself called from a batch file on Windows, but it needs to be executed as root.
The first solution I tried was to call the script using
adb shell "su -c sh /bin/script.sh"
but it does not work as it gives me a shell access (with root permissions), but nothing is executed.
I also tried to call
adb root "sh /bin/script.sh"
but I got the following error
adbd cannot run as root in production builds
I then tried to write
su -c "command"
for all the commands which need a root access in my script, but I have the same problem.
When I run the script I only obtain a root shell and nothing is executed.
If I use the first solution by hand (e.g. I call adb shell su, then my script), it works. However the whole point is to automate the process, so that adb shell can be called from another script.
Do you have any idea of how I could achieve this ?
Thanks !

This works for me:
Create myscript.bat and put into it (note the single quotes around the commands to be executed in superuser mode):
adb shell "su -c 'command1; command2; command3'"
then run myscript.bat from a DOS shell.
Note: it doesn't appear that the the DOS line continuation character (^) works in this situation. In other words, the following doesn't work for me:
adb shell "su -c '^
command1; ^
command2; ^
command3'"
This results in "Syntax error: Unterminated quoted string"

This works :
adb shell echo command which needs root privileges \| su
If you need redirection:
adb shell echo 'echo anytext > /data/data/aforbiddenfolder/file' \| su
For "copying" a local file to an android path needing root privileges (but alocalfile must not contain '):
cat alocalfile | adb shell echo "echo '`cat`' > /data/data/aforbiddenfolder/file" \| su
If you have a better way (even for su versions which don't have -c), I am interested.

This works for me:
adb shell "su -c ./data/local/tcpdump-arm -s 0 -v -w /data/local/appxpress_dump.pcap"

I am not sure if I provided a solution or asked for a better one.
I wanted to run some 200 command in batch mode to be sent to adb
I followed this approach
adb shell "su -c command ; "
adb shell "su -c command ; "
adb shell "su -c command ; "
adb shell "su -c command ; "
and I saved them in a batch file
This command
adb shell "su -c 'command1; command2; command3'"
will not work beyond a certain max size . It did not work
error: service name too long

but it does not work as it gives me a shell access (with root permissions), but nothing is executed.
How do you know that you are given root permissions? I assume you are attempting to execute the script on a device? Has your device been rooted?
You may need to give execute permissions via chmod to the file.
chmod ugo=rwx /bin/script.sh

It appears that I was using a very simple version of su which did not accept the -c argument.
I copied another su which did work. AndyD is totally right though, so I am accepting his answer instead of mine :)