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Thread: Understanding Android file permissions

  1. #1
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    Default Understanding Android file permissions

    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

    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

    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.
    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 = 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

    Last edited by Eugene373; 05-12-2010 at 09:20 AM.
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  2. #2
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    Jun 2010
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    Default Re: Understanding Android file permissions

    That just is the same as the file system in linux. Because android are based on linux.

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