How do I get permission to create this file in an android shell?

Question

I'm trying to root a Kindle and I'm stuck. Getting permission denied and don't know how or what permissions to change.

mike@Inspiron:~/Downloads/android-sdk-linux/platform-tools$ adb shell
shell@android:/ $ echo 'ro.kernel.qemu=1' > /data/local.prop
/system/bin/sh: cannot create /data/local.prop: Permission denied
1|shell@android:/ $ sudo echo 'ro.kernel.qemu=1' > /data/local.prop            
/system/bin/sh: cannot create /data/local.prop: Permission denied
1|shell@android:/ $ sudo
/system/bin/sh: sudo: not found
127|shell@android:/ $

I'm using Ubuntu 12.04 if it makes a difference.

Answer 1

Short answer: You will have to root your device for that.

Explanation: The shell user has no write permission there. The /data directory is not owned by shell, nor does their group match: on my Motorola Milestone 2, e.g., it is owned by system:system and has the permissions drwxrwxr-x, while shell belongs to the shell group only. Only on a rooted device you could either change the permissions, or be privileged enough to override them.

PS: On Android, the sudo command is simply called su -- which explains your last error (/system/bin/sh: sudo: not found) in case your device is already rooted.

Answer 2

Try this:

adb shell "cd /data/local && mkdir tmp"
adb shell mv /data/local/tmp /data/local/tmp.bak
adb shell ln -s /data /data/local/tmp
adb reboot

adb wait-for-device
adb shell rm /data/local.prop
adb shell "echo \"ro.kernel.qemu=1\" > /data/local.prop"
adb reboot

By creating a link to from /data to /data/local/tmp, Android will believe you are writing to /data/local/tmp even though you're actually writing to /data. This method is actually used to successfully root many devices, though some have it specifically in the build.prop that /data/tmp is off limits.

This method might not work with a Kindle Fire, though I haven't tried. I have rooted a Kindle Fire, but it involved a different method entirely. First, TWRP recovery had to be flashed. Then, a fake recovery image exploit. Then, you could gain access to copy over your su and busybox binaries.

You can try the local.prop method as I described above though. It is compatible with many devices.

Answer 3

You did not follow the rooting instruction properly.

http://rootzwiki.com/topic/34162-root-kindlefire-7hd-probably-the-other-2ndgen-kindlefire/

The instruction above would have you create symbolic links to the /data/ directory from /data/local/tmp/ which would make the /data/local.prop writable after a reboot.

Make sure you follow the instructions precisely, including the reboots and all, and make sure you check each step that they do not produce unexpected error message.