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User profile for user: bbos
bbos Author
User level: Level 1
4 points

chown will not work on external drives

*Is there a better guide to the wiki markup you can use than the Help page in the list on the RH side of this page? I had to guess at code in braces - it wasn't listed on that page. Is there a way to do tables, bullets??*

h1. Chown will not work on external drives
* MacOSX 10.5.7
** From memory this wasn't a problem on MacOSX 10.4
* These drives were tested:
** (internal) system drive
** (terra) 2 x 1TB Drives setup with Raid 1 to be 1TB mirrored drive
** (240g) 1 x 240GB Drive
** (usb stick) 1 x 256MB USB Drive

h2. Summary 

|| Drive ||chmod||chown
|| Internal |yes |yes
|| terra |yes |no
|| 240g |yes |no
|| usb stick|no |no


h2. Demonstration
* Start on an external drive
* Do some listings. These show:
** File flags (-O option)
** User / Group ID (-n) or User / Group name (no -n)
** Look at files as user (bsmith) and root 

bsmith@kanga ~ $ cd /Volumes/terra
bsmith@kanga terra $ ls -lO
total 32
 2 0 drwxrwxr-x 21 bsmith staff - 782 21 Jul 21:08 ./
 23026 0 drwxrwxrwt@ 11 root admin hidden 374 23 Jul 20:40 ../
 85 16 -rw-rw-r--@ 1 bsmith staff hidden 6148 17 Jul 14:31 .DS_Store
 24 0 drwx------ 3 bsmith staff - 102 17 Jul 07:26 .Spotlight-V100/
 91960 0 drwxrwxrwt@ 3 bsmith staff hidden 102 17 Jul 09:17 .TemporaryItems/
 20 0 d-wx-wx-wt 3 bsmith staff - 102 17 Jul 07:26 .Trashes/
 31 0 -rw-r--r-- 1 bsmith staff - 0 17 Jul 07:26 .com.apple.timemachine.supported
 21 0 drwx------ 59 bsmith staff - 2006 21 Jul 22:59 .fseventsd/
464482 0 drwx------ 4 bsmith staff - 136 19 Jul 17:27 Desktop/
463572 8 -rw-r--r--@ 1 bsmith staff hidden 1024 17 Jul 19:44 Desktop DB
463573 8 -rw-r--r--@ 1 bsmith staff hidden 2 17 Jul 19:44 Desktop DF
 87 0 drwxr-xr-x@ 694 bsmith staff - 23596 23 Jul 07:33 Music/
 88 0 drwxr-xr-x@ 50 bsmith staff - 1700 17 Jul 07:46 Pictures/
 93976 0 drwxr-xr-x 4 bsmith staff - 136 17 Jul 15:07 Users/
 98587 0 drwxr-xr-x 8 bsmith staff - 272 17 Jul 15:45 backup/
464604 0 drwxr-xr-x@ 3 bsmith staff - 102 21 Jul 19:10 downloads/
130207 0 drwxr-xr-x 13 bsmith staff - 442 21 Jan 2007 home/
464642 0 drwxrwx--- 3 bsmith staff - 102 21 Jul 20:43 manuals/
464644 0 drwxrwxrwx 3 bsmith staff - 102 21 Jul 21:08 opt/

* Show IDs instead of names 

bsmith@kanga terra $ ls -lOn
total 32
 2 0 drwxrwxr-x 21 501 20 - 782 21 Jul 21:08 ./
 23026 0 drwxrwxrwt@ 11 0 80 hidden 374 23 Jul 20:40 ../
 85 16 -rw-rw-r--@ 1 501 20 hidden 6148 17 Jul 14:31 .DS_Store
 24 0 drwx------ 3 501 20 - 102 17 Jul 07:26 .Spotlight-V100/
 91960 0 drwxrwxrwt@ 3 501 20 hidden 102 17 Jul 09:17 .TemporaryItems/
 20 0 d-wx-wx-wt 3 501 20 - 102 17 Jul 07:26 .Trashes/
 31 0 -rw-r--r-- 1 501 20 - 0 17 Jul 07:26 .com.apple.timemachine.supported
 21 0 drwx------ 59 501 20 - 2006 21 Jul 22:59 .fseventsd/
464482 0 drwx------ 4 501 20 - 136 19 Jul 17:27 Desktop/
463572 8 -rw-r--r--@ 1 501 20 hidden 1024 17 Jul 19:44 Desktop DB
463573 8 -rw-r--r--@ 1 501 20 hidden 2 17 Jul 19:44 Desktop DF
 87 0 drwxr-xr-x@ 694 501 20 - 23596 23 Jul 07:33 Music/
 88 0 drwxr-xr-x@ 50 501 20 - 1700 17 Jul 07:46 Pictures/
 93976 0 drwxr-xr-x 4 501 20 - 136 17 Jul 15:07 Users/
 98587 0 drwxr-xr-x 8 501 20 - 272 17 Jul 15:45 backup/
464604 0 drwxr-xr-x@ 3 501 20 - 102 21 Jul 19:10 downloads/
130207 0 drwxr-xr-x 13 501 20 - 442 21 Jan 2007 home/
464642 0 drwxrwx--- 3 501 20 - 102 21 Jul 20:43 manuals/
464644 0 drwxrwxrwx 3 501 20 - 102 21 Jul 21:08 opt/

* become root and show listings again 

bsmith@kanga terra $ su -
Password:
kanga:~ root# cd /Volumes/terra
kanga:terra root# ls -laO 
total 32
drwxrwxr-x 21 _unknown _unknown - 782 Jul 21 21:08 .
drwxrwxrwt@ 11 root admin hidden 374 Jul 23 20:40 ..
-rw-rw-r--@ 1 _unknown _unknown hidden 6148 Jul 17 14:31 .DS_Store
drwx------ 3 _unknown _unknown - 102 Jul 17 07:26 .Spotlight-V100
drwxrwxrwt@ 3 _unknown _unknown hidden 102 Jul 17 09:17 .TemporaryItems
d-wx-wx-wt@ 3 _unknown _unknown - 102 Jul 17 07:26 .Trashes
-rw-r--r-- 1 _unknown _unknown - 0 Jul 17 07:26 .com.apple.timemachine.supported
drwx------ 59 _unknown _unknown - 2006 Jul 21 22:59 .fseventsd
drwx------ 4 _unknown _unknown - 136 Jul 19 17:27 Desktop
-rw-r--r--@ 1 _unknown _unknown hidden 1024 Jul 17 19:44 Desktop DB
-rw-r--r--@ 1 _unknown _unknown hidden 2 Jul 17 19:44 Desktop DF
drwxr-xr-x@ 694 _unknown _unknown - 23596 Jul 23 07:33 Music
drwxr-xr-x@ 50 _unknown _unknown - 1700 Jul 17 07:46 Pictures
drwxr-xr-x 4 _unknown _unknown - 136 Jul 17 15:07 Users
drwxr-xr-x 8 _unknown _unknown - 272 Jul 17 15:45 backup
drwxr-xr-x@ 3 _unknown _unknown - 102 Jul 21 19:10 downloads
drwxr-xr-x 13 _unknown _unknown - 442 Jan 21 2007 home
drwxrwx--- 3 _unknown _unknown - 102 Jul 21 20:43 manuals
drwxrwxrwx 3 _unknown _unknown - 102 Jul 21 21:08 opt

* Notice that it is showing different userid.
* Without the 'show only user / group id' switch 

kanga:terra root# ls -laOn
total 32
drwxrwxr-x 21 99 99 - 782 Jul 21 21:08 .
drwxrwxrwt@ 11 0 80 hidden 374 Jul 23 20:40 ..
-rw-rw-r--@ 1 99 99 hidden 6148 Jul 17 14:31 .DS_Store
drwx------ 3 99 99 - 102 Jul 17 07:26 .Spotlight-V100
drwxrwxrwt@ 3 99 99 hidden 102 Jul 17 09:17 .TemporaryItems
d-wx-wx-wt@ 3 99 99 - 102 Jul 17 07:26 .Trashes
-rw-r--r-- 1 99 99 - 0 Jul 17 07:26 .com.apple.timemachine.supported
drwx------ 59 99 99 - 2006 Jul 21 22:59 .fseventsd
drwx------ 4 99 99 - 136 Jul 19 17:27 Desktop
-rw-r--r--@ 1 99 99 hidden 1024 Jul 17 19:44 Desktop DB
-rw-r--r--@ 1 99 99 hidden 2 Jul 17 19:44 Desktop DF
drwxr-xr-x@ 694 99 99 - 23596 Jul 23 07:33 Music
drwxr-xr-x@ 50 99 99 - 1700 Jul 17 07:46 Pictures
drwxr-xr-x 4 99 99 - 136 Jul 17 15:07 Users
drwxr-xr-x 8 99 99 - 272 Jul 17 15:45 backup
drwxr-xr-x@ 3 99 99 - 102 Jul 21 19:10 downloads
drwxr-xr-x 13 99 99 - 442 Jan 21 2007 home
drwxrwx--- 3 99 99 - 102 Jul 21 20:43 manuals
drwxrwxrwx 3 99 99 - 102 Jul 21 21:08 opt

* Now try this on then internal system drive 

kanga:terra root# cd /Users/bsmith/tmp/
kanga:tmp root# ls -laO
total 0
drwxr-xr-x@ 3 bsmith staff - 102 Jul 21 21:19 .
drwxr-xr-x+ 34 bsmith staff - 1156 Jul 23 09:56 ..
drwxr-xr-x@ 3 bsmith staff - 102 Jul 19 09:05 work

kanga:tmp root# ls -laOn
total 0
drwxr-xr-x@ 3 501 20 - 102 Jul 21 21:19 .
drwxr-xr-x+ 34 501 20 - 1156 Jul 23 09:56 ..
drwxr-xr-x@ 3 501 20 - 102 Jul 19 09:05 work

* Stop being root 

^D
bsmith@kanga tmp $ ls -laO
total 0
1343345 0 drwxr-xr-x@ 3 bsmith staff - 102 21 Jul 21:19 ./
 688986 0 drwxr-xr-x+ 34 bsmith staff - 1156 23 Jul 09:56 ../
1343346 0 drwxr-xr-x@ 3 bsmith staff - 102 19 Jul 09:05 work/

* Show user and group names 

bsmith@kanga tmp $ ls -laOn
total 0
1343345 0 drwxr-xr-x@ 3 501 20 - 102 21 Jul 21:19 ./
 688986 0 drwxr-xr-x+ 34 501 20 - 1156 23 Jul 09:56 ../
1343346 0 drwxr-xr-x@ 3 501 20 - 102 19 Jul 09:05 work/


So there is some odd displays in the listing 

||User listing||User name/id||Drive
|bsmith|bsmith/501| internal and external drives
|root|bsmith/501 | internal drives
|root|unknown/99 | external drives


h3. ACLs
* ACLs have not been applied (-e): 

bsmith@kanga terra $ ls -lae
total 32
 2 0 drwxrwxr-x 21 bsmith staff 782 21 Jul 21:08 ./
 23026 0 drwxrwxrwt@ 10 root admin 340 23 Jul 22:55 ../
 85 16 -rw-rw-r--@ 1 bsmith staff 6148 17 Jul 14:31 .DS_Store
 24 0 drwx------ 3 bsmith staff 102 17 Jul 07:26 .Spotlight-V100/
 91960 0 drwxrwxrwt@ 3 bsmith staff 102 17 Jul 09:17 .TemporaryItems/
 20 0 d-wx-wx-wt 3 bsmith staff 102 17 Jul 07:26 .Trashes/
 31 0 -rw-r--r-- 1 bsmith staff 0 17 Jul 07:26 .com.apple.timemachine.supported
 21 0 drwx------ 59 bsmith staff 2006 21 Jul 22:59 .fseventsd/
464482 0 drwx------ 4 bsmith staff 136 19 Jul 17:27 Desktop/
463572 8 -rw-r--r--@ 1 bsmith staff 1024 17 Jul 19:44 Desktop DB
463573 8 -rw-r--r--@ 1 bsmith staff 2 17 Jul 19:44 Desktop DF
 87 0 drwxr-xr-x@ 694 bsmith staff 23596 23 Jul 23:14 Music/
 88 0 drwxr-xr-x@ 50 bsmith staff 1700 17 Jul 07:46 Pictures/
 93976 0 drwxr-xr-x 4 bsmith staff 136 17 Jul 15:07 Users/
 98587 0 drwxr-xr-x 8 bsmith staff 272 17 Jul 15:45 backup/
464604 0 drwxr-xr-x@ 3 bsmith staff 102 21 Jul 19:10 downloads/
130207 0 drwxr-xr-x 13 bsmith staff 442 21 Jan 2007 home/
464642 0 drwxrwx--- 3 bsmith staff 102 21 Jul 20:43 manuals/
464644 0 drwxrwxrwx 3 bsmith staff 102 21 Jul 21:08 opt/


Thanks for reading this and thanks too for any answers.

Brooke

Mac Mini 2.0GHz Intel Core 2 Duo, 4GB; Samsung 2494HS 23.6"., Mac OS X (10.5.7), Macbook Pro 2.4 GHz Intel Core 2 Duo (2007), iMac 20" (2004)

Posted on Jul 23, 2009 7:20 AM

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User profile for user: biovizier
biovizier
User level: Level 5
7,925 points

Posted on Jul 23, 2009 8:25 AM

From the output, it is clear that the drives have "ownership" disabled, or owners aren't supported under OS X (eg. if the drive is FAT formatted).

When ownership on a volume is disabled, everything is treated as if it is owned by the user and group "unknown" (' uid' and ' gid' 99). Items owned by "unknown" have the property of appearing to be owned by the owner of the process attempting to access the item, and only "root" can see their true nature (in 10.4 and later). In this context, ' chown' isn't meaningful.

To see if ownership is enabled, use "Disk Utility.app", and possibly "Get Info" in the "Finder". Or else, on the command line, eg:<pre>
vsdbutil -c /Volumes/terra</pre>

Ownership can be enabled (assuming the volume format supports it) using the GUI, or with eg.:<pre>
/usr/bin/sudo /usr/sbin/vsdbutil -a /Volumes/terra</pre>
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2 replies
Question marked as Top-ranking reply
User profile for user: biovizier
biovizier
User level: Level 5
7,925 points

Jul 23, 2009 8:25 AM in response to bbos

From the output, it is clear that the drives have "ownership" disabled, or owners aren't supported under OS X (eg. if the drive is FAT formatted).

When ownership on a volume is disabled, everything is treated as if it is owned by the user and group "unknown" (' uid' and ' gid' 99). Items owned by "unknown" have the property of appearing to be owned by the owner of the process attempting to access the item, and only "root" can see their true nature (in 10.4 and later). In this context, ' chown' isn't meaningful.

To see if ownership is enabled, use "Disk Utility.app", and possibly "Get Info" in the "Finder". Or else, on the command line, eg:<pre>
vsdbutil -c /Volumes/terra</pre>

Ownership can be enabled (assuming the volume format supports it) using the GUI, or with eg.:<pre>
/usr/bin/sudo /usr/sbin/vsdbutil -a /Volumes/terra</pre>
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chown will not work on external drives

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