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Root Can't change file permissions with Root Explorer

P

pancake_old

Guest
Yes, the phone is rooted ;)

Specifically, when I go to /mnt/sdcard/download all the files are ---rwxr-x. When I long-click a file I can access a Permissions dialog, but any changes I make there are not actually reflected on the file system. Anyone know what might be going on?
 
Bumping.. Can anyone please try this? I want to know if this is the expected behavior.

Thanks!
 
pancake said:
Yes, the phone is rooted ;)

Specifically, when I go to /mnt/sdcard/download all the files are ---rwxr-x. When I long-click a file I can access a Permissions dialog, but any changes I make there are not actually reflected on the file system. Anyone know what might be going on?
Click to expand...

pancake,

I've wondered the same things myself. I believe the issue is that the files you are trying to manipulate are on the /sdcard and there's clearly some mechanism for preventing the changing of the file's permission bits (probably to help prevent rooting, I'm guessing).

I did a little manual test on my Droid Eris and my Droid X (got the same results on both; here's the results from my Droid X):

d:\android-sdk-windows\tools>adb shell
$ su
su
# cd /sdcard
cd /sdcard
# busybox touch testfile
busybox touch testfile
# ls -a -l testfile
ls -a -l testfile
----rwxr-x system sdcard_rw 0 2010-11-18 23:19 testfile
# chmod 777 testfile
chmod 777 testfile
# ls -a -l testfile
ls -a -l testfile
----rwxr-x system sdcard_rw 0 2010-11-18 23:19 testfile
# rm testfile
rm testfile
#

Okay, now doing similar things on filesystems located under the root directory yields much different results (i.e., permission settings are honored):

# cd /data/data
cd /data/data
# busybox touch testfile
busybox touch testfile
# ls -a -l testfile
ls -a -l testfile
-rw-rw-rw- root root 0 2010-11-18 23:19 testfile
# chmod 777 testfile
chmod 777 testfile
# ls -a -l testfile
ls -a -l testfile
-rwxrwxrwx root root 0 2010-11-18 23:19 testfile
# chmod 555 testfile
chmod 555 testfile
# ls -a -l testfile
ls -a -l testfile
-r-xr-xr-x root root 0 2010-11-18 23:19 testfile
# chmod 500 testfile
chmod 500 testfile
# ls -a -l testfile
ls -a -l testfile
-r-x------ root root 0 2010-11-18 23:19 testfile
# rm testfile
rm testfile
#

Not a total answer, I know, but something...

Cheers!
 
After Android Al posted the information about FAT32 being the relevant piece of information above (thanks again, btw), I just had to know a little more about what is going on.

I found a very good / interesting discussion about this here: Why no executables on FAT32 (SD card)? (Page 1) / General Discussion / EeeUser Forum (I know, its on an Asus EEE forum, but I think the concepts discussed are relevant to our Android phones).

At the very least, it discusses some of the issues / reasons for this (noexec/fmask mount settings, execution bits, etc.). Not sure I understood all of it, but suffice to say that there are several things in place to keep the permissions from being monkeyed with ;).

Cheers!
 
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