Umask didn't do it's job...

Mr. Alex · 12-14-2011, 09:48 AM

Hello!
I have umask set in /etc/profile to "000". But I get new files onto my HDD with permissions such as "-rw-r--r--". For example it's my recent file downloaded from torrents. How come it's not "-rw-rw-rw-"?

rknichols · 12-14-2011, 10:13 AM

The umask only subtracts from the permission bits that the application requests. If the application requests "rw-r--r--", that's the most you will ever see.

catkin · 12-14-2011, 10:23 AM

Bash creates rw-rw-rw on my system when the umask is 000

rknichols · 12-15-2011, 07:49 AM

Quote:

Originally Posted by Mr. Alex

For example it's my recent file downloaded from torrents.

The file was created by your bittorrent client, which probably set the permissions the file had on the original seed. Bash had nothing to do with it.

Mr. Alex · 12-15-2011, 08:33 AM

Tried several files from torrents - all with same permissions. I really don't think all those seeds have *nix operating systems. My guess is that any Linux program can have it's own default file permissions and doesn't take your system umask (it's up to program which umask to use).

catkin · 12-15-2011, 08:59 AM

Quote:

Originally Posted by Mr. Alex

Tried several files from torrents - all with same permissions. I really don't think all those seeds have *nix operating systems. My guess is that any Linux program can have it's own default file permissions and doesn't take your system umask (it's up to program which umask to use).

The way it works is that the torrent program creates the file using the creat (that's right - no final e) or open system call specifying the permissions in the mode argument. The system will subtract any requested bits "masked out" by the current umask setting (none if the umask is 000).

More information in the creat man page.