Name
os_chmod — changes the file access mode of a file
Synopsis
os_chmod
(
|
in path varchar , |
in
new_mod
integer
); |
Description
os_chmod
set the file mode bits
by calling the system function chmod() with the arguments supplied.
Not all the host OSes support all the file modes. That's why the function will not throw an SQL error if the function fails.
It will return DB NULL value when the function was called successfully and the error message as a string if it failed.
In most OSes the mode is a bitmask, so one would usually use the
file_stat
to get the current mode and
bit_or
/bit_xor
to make the new
mode.
Typical bit layout (from Linux 'man 2 chmod') is :
| bit 0 (mask 1) - execute/search by others |
| bit 1 (mask 2) - write by others |
| bit 2 (mask 4) - read by others |
| bit 3 (mask 8) - execute/search by group |
| bit 4 (mask 16) - write by group |
| bit 5 (mask 32) - read by group |
| bit 6 (mask 64) - execute/search by owner |
| bit 7 (mask 128) - write by owner |
| bit 8 (mask 256) - read by owner |
| bit 9 (mask 512) - sticky bit |
| bit 10 (mask 1024) - set group ID on execution |
| bit 12 (mask 2048) - set user ID on execution |
The DirsAllowed and DirsDenied lists in Parameters section of the virtuoso configuration file (virtuoso.ini by default) are used to control disk access.
Parameters
path
varchar relative path.
new_mod
integer new mode for the file.
Examples
Example 24.242. Simple example
Make the virtuoso INI file readable by the others
SQL>select os_chmod (virtuoso_ini_path(), bit_or (cast (file_stat (virtuoso_ini_path(), 2) as integer), 4)); callret VARCHAR _______________________________________________________________________________ NULL