Set write permissions on ProgramData subfolder using JNA

2
votes

I have a program, written in Java, which originally used its directory in Program Files to write files accessible to all users of this program. This required our users to run as administrator all the time. In an effort to alleviate that, we decided to move files which needed to be written during regular usage to the ProgramData folder using the %ALLUSERSPROFILE% environment variable. Using a subfolder in this directory for our application works great if it is designated as writable during the installation process, which works fine using NSIS.

The problem comes with upgrading existing users. The Java File API provides setWritable but this does not appear to work after testing on development machines. It looks as though the new file API with Java 7 would solve this problem, but with no release date on the horizon I would rather not wait.

It seems the simplest solution would be to use JNA to call the appropriate Windows API call to set this directory writable. Since upgrading the software necessitates admin rights, similar to installing, it should let this change go through fine. However, I'm unsure where to start, having never used JNA before or the Windows API. Suggestions as to which Windows library to load and what functions to call would be appreciated, especially if someone has encountered a similar problem before.

2
javawindowsjna
IMHO too broad question. Try to read some more on JNA / WinAPI functions you may need and narrow the question. - pajton
I may be missing something, but why not just use cacls? - Dmitri
@Dmitri: As a primarily Java guy, I didn't know about it. - Thorn G

2 Answers

0
votes

Well, I'm glad you gave some background...You could use JNA, but the easier way would be to execute a call to the command-line utility cacls. It's included by default in Windows XP installations, I believe, so it should do the trick for you. Try Runtime.getRuntime().exec("C:\\Windows\\System32\\cacls.exe"+options)

Check out the documentation here -> http://technet.microsoft.com/en-us/library/bb490872.aspx

0
votes

I use the follow line:

Runtime.getRuntime().exec( "C:\\Windows\\System32\\icacls.exe \"%ProgramData%\my application" /grant *S-1-5-32-545:(OI)(CI)(W,M)" );

S-1-5-32-545 is the SID for BUILTIN\Users because the name work only on English systems. https://support.microsoft.com/de-de/kb/163846

This give the BUILTIN\Users write access to all files in the given directory independent which user has create it.