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Root Understanding Android file permissions

BH_MAN

Android Expert
Feb 17, 2010
1,381
1,667
Understanding Android file permissions

Overview Of Permissions via ADB SHELL
Example = drwxrwxrwx

To Check Permission at anytime in ADB just Type:
ls -l

The First character defines the Directory, Link, Binary.
Below are some examples

Example = d---------
d = Directory
l = Link
b = Binary



The next 9 characters define the file permissions. These permissions are
given in groups of 3 each.

The first 3 characters are the permissions for the owner of the file or directory.
Example = -rwx------

The next 3 are permissions for the group that the file is owned by.
Example = ----rwx---

The final 3 characters define the access permissions for everyone not part of the group.
Example = -------rwx

There are 3 possible attributes that make up file access permissions.

r - Read permission. Whether the file may be read. In the case of a
directory, this would mean the ability to list the contents of the
directory.

w - Write permission. Whether the file may be written to or modified. For
a directory, this defines whether you can make any changes to the contents
of the directory. If write permission is not set then you will not be able
to delete, rename or create a file.

x - Execute permission. Whether the file may be executed. In the case of a
directory, this attribute decides whether you have permission to enter,
run a search through that directory or execute some program from that
directory

In addition to the file permission, you can also modify the owner and
group of the file. The chown program is used here and its syntax is very
simple. You need to be the owner of a file or root to do this.

Understanding Owner Permissions:
The first command is for
owner ID, the Second Command is for Group ID.
exp.
root.root ( First Root is owner, Second Root is Group ).

Chmod 644 some file, Like
Build.prop For testing & then Veiw the Resulted Changes!
Refer to the table below as a quick reference.

Command Line for Both would look like this


chmod 644 build.prop = -rw-r--r--
\/
Chmod Guide
0 - ---
1 - --x
2 - -w-
3 - -wx
4 - r--
5 - r-x
6 - rw-
7 - rwx

Behold 2 SH Chown Guide
\/

chown root.root build.prop
root.root = Root
root.shell = Shell

Busybox SH Chown Guide
\/
chown 0.0 build.prop
0.0 = Root
0.2000 = Shell

I'll update the chmod with more with More Complex Commands Later

Side Note:Always set owner ( chown ) before Setting Permissions ( Chmod )!

Hope this Clears up things & is Helpful to everyone
~BH_MAN


 
chmod - Wikipedia, the free encyclopedia

Just be aware that the flash file system used on the BH2 cannot save permissions. If you make any changes they will have to be redone after a reboot.

I never had any of these issue when I worked from my Rom's..

Just use Busybox when changing permissions.. if they don't stick, but them again I never had issue.. As you as Root via sh which lets you change permission & have them stick after a reboot.
 
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