tedd wrote:
At 11:18 AM -0400 5/17/06, John Nichel wrote:
tedd wrote:
Hi (please insert your preference):
This should be simple, but I'm having problems.
I have a program that uploads an image file and then tries to set the
permissions for the image (to be altered later). However, I get a
"Warning: chmod(): Operation not permitted" error when trying to set
the permission, what gives? If my program created the file, shouldn't
it have permission to set the files permissions?
What am I not understanding?
Without seeing code, permissions of the directories, what sticky bits
might or might not be set, etc., you could not be understanding many
things....or just one....who knows.
I read all of your Google links, but no help. Just another example of
how Google is not the answer.
Then you're asking the wrong question.
In any event, my code is pretty simple, just:
chmod($url, 0755); //where $url is the file I want to change.
The error I receive is noted above in the subject line.
The permissions of the directories vary, but the folder that has the
file I want to change permissions is currently set at 0777.
Nice security there. Regardless, even if the user your webserver is
running as has write permission to the directory (don't know who
owns/what group that directory belongs to, as you didn't tell us that),
you won't be able to change permissions of a file in that directory if
the file isn't owned by the same user apache is running as.
In doing a lstat() of both the parent program that created the file and
the child file shows that they both have the identical uid and gid
(i.e., the same user and group id's).
And what user does Apache run as?
Now, everything I've read, says:
chmod() changes the permission of the specified file with the following
caveat.
"chmod() can only change the permissions of files that are owned by the
user running the command. In most cases, this is the user that the web
server runs on."
That confuses me, because who's the user here? Is it just the system
administrator or the application?
And if it is just the system administrator, then can't the system admin
change anything he/she wants anyway? What's the point of having uid and
gid's if a program can't change the permissions of a sibling file?
This question should answer the previous question for you.
I have tons of references as to what php filesystem functions are
available, but I need a good reference as to what permissions are and
how they actually can be changed in php -- does anyone have one a good
reference OR care to explain?
As it is now, I know how ride the horse, but I can't get the gate open.
File permissions is beyond the scope of this mailing list. You need to
buy a book, research on the web, etc., on *nix system administration,
and concentrate on the filesystem/security/permissions sections, and the
section on how apps/daemons operate.
--
John C. Nichel IV
Programmer/System Admin (ÜberGeek)
Dot Com Holdings of Buffalo
716.856.9675
jnichel@xxxxxxxxxxxxxxxxxxxxxxxxxxx
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