Re: links vs real directories
On Mon, Mar 16, 2009 at 11:22:13AM -0400, John Almberg wrote: I always thought that links to real directories were pretty much the same as real directories, but I've just discovered a situation where they are not and I'm wondering if I'm doing something wrong... A *soft* link to a directory entry (be it a directory or a file or something else) is not quite equivalent to the original entry since they are easily distinguished and some programs do treat softlinks differently from other targets. A hardlink to a file is exactly equivalent to the original (since the original directory entry is itself a hardlink). The system does not however allow you to create hardlinks to directories since it is far too easy to make Very Bad Things happen that way. I have a Ruby on Rails application running on a FreeBSD server. All Rails apps use the same directory structure, that consists of an application directory, plus a number of subdirectories. One of these sub directories is called 'config'. I would like to move this config directory out of the main Rails app directory, and then add a link from the app directory to the moved config directory. so: app -- config will become app -- config(link) -- config Basically, what I'm doing is: cd ~/app # now in directory with real 'config' dir mv config ~/shared/config ln -s ~/shared/config config That moves the directory and creates a functional link to it (I tested it), but Rails doesn't like it and refuses to run the app. The permissions are correct, I believe: [mas...@on:current] ls -l total 34 ... snip ... drwxrwxr-x 3 master master 512 Mar 16 11:06 bin drwxrwxr-x 3 master master 512 Mar 16 11:06 components lrwxr-xr-x 1 master master26 Mar 16 11:07 config - /home/ master/shared/config drwxr-xr-x 4 master master 512 Mar 16 11:06 db etc... So, I guess a link is NOT exactly equivalent to a directory. At least not the way I am doing it. I'm guessing I'm making a real newbie mistake, so if anyone can set me straight, I'd appreciate it. Thank: John -- Insert your favourite quote here. Erik Trulsson ertr1...@student.uu.se ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: links vs real directories
On Mar 16, 2009, at 11:22 AM, John Almberg wrote:
I always thought that links to real directories were pretty much
the same as real directories, but I've just discovered a situation
where they are not and I'm wondering if I'm doing something wrong...
I have a Ruby on Rails application running on a FreeBSD server. All
Rails apps use the same directory structure, that consists of an
application directory, plus a number of subdirectories. One of
these sub directories is called 'config'.
I would like to move this config directory out of the main Rails
app directory, and then add a link from the app directory to the
moved config directory.
so:
app -- config
will become
app -- config(link) -- config
Basically, what I'm doing is:
cd ~/app # now in directory with real 'config' dir
mv config ~/shared/config
ln -s ~/shared/config config
That moves the directory and creates a functional link to it (I
tested it), but Rails doesn't like it and refuses to run the app.
The permissions are correct, I believe:
[mas...@on:current] ls -l
total 34
... snip ...
drwxrwxr-x 3 master master 512 Mar 16 11:06 bin
drwxrwxr-x 3 master master 512 Mar 16 11:06 components
lrwxr-xr-x 1 master master26 Mar 16 11:07 config - /home/
master/shared/config
drwxr-xr-x 4 master master 512 Mar 16 11:06 db
etc...
So, I guess a link is NOT exactly equivalent to a directory. At
least not the way I am doing it.
I'm guessing I'm making a real newbie mistake, so if anyone can set
me straight, I'd appreciate it.
Thank: John
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A little more information on this... from the Rails log, I can see
that a Ruby script in the config directory cannot load ('require') a
needed file because it can't find it:
/usr/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in
`gem_original_require': no such file to load -- application
(MissingSource File)
It looks like this require statement is using a relative path, like
'../path/to/file'. Does '..' not work properly with a soft link? In
other words, '..', should mean ~/app, but since the config directory
is really in '~/shared', perhaps '..' translates to '~/shared'? That
would cause the problem finding the file.
Is there a way around this problem?
Digging in man ls, right now..
-- John
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Re: links vs real directories
On Mar 16, 2009, at 11:39 AM, Erik Trulsson wrote: On Mon, Mar 16, 2009 at 11:22:13AM -0400, John Almberg wrote: I always thought that links to real directories were pretty much the same as real directories, but I've just discovered a situation where they are not and I'm wondering if I'm doing something wrong... A *soft* link to a directory entry (be it a directory or a file or something else) is not quite equivalent to the original entry since they are easily distinguished and some programs do treat softlinks differently from other targets. I can see that, now... If I create a soft link to ~/shared/config, and then cd into the directory, when I type 'ls ..', I get the listing for ~/shared, not ~/app. Bummer... I've just dug through man ln, and don't see any obvious solution. Since this must be a problem for anyone who wants to do something like this, I guess I am taking the wrong approach, altogether. Will have to re-think this smell of burning rubber commences... -- John ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: links vs real directories
On Mar 16, 2009, at 11:47 AM, John Almberg wrote: On Mar 16, 2009, at 11:39 AM, Erik Trulsson wrote: On Mon, Mar 16, 2009 at 11:22:13AM -0400, John Almberg wrote: I always thought that links to real directories were pretty much the same as real directories, but I've just discovered a situation where they are not and I'm wondering if I'm doing something wrong... A *soft* link to a directory entry (be it a directory or a file or something else) is not quite equivalent to the original entry since they are easily distinguished and some programs do treat softlinks differently from other targets. I can see that, now... If I create a soft link to ~/shared/config, and then cd into the directory, when I type 'ls ..', I get the listing for ~/shared, not ~/app. Bummer... I've just dug through man ln, and don't see any obvious solution. Since this must be a problem for anyone who wants to do something like this, I guess I am taking the wrong approach, altogether. Will have to re-think this smell of burning rubber commences... Okay! I guess I wasn't the first to have this problem... lndir (in ports) solves the problem by creating a set of soft links for all the files in the 'linked' directory. Kinda kludgy, but it works. -- John ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: links vs real directories
On Mon, Mar 16, 2009 at 11:47:23AM -0400, John Almberg wrote: On Mar 16, 2009, at 11:39 AM, Erik Trulsson wrote: On Mon, Mar 16, 2009 at 11:22:13AM -0400, John Almberg wrote: I always thought that links to real directories were pretty much the same as real directories, but I've just discovered a situation where they are not and I'm wondering if I'm doing something wrong... A *soft* link to a directory entry (be it a directory or a file or something else) is not quite equivalent to the original entry since they are easily distinguished and some programs do treat softlinks differently from other targets. I can see that, now... If I create a soft link to ~/shared/config, and then cd into the directory, when I type 'ls ..', I get the listing for ~/shared, not ~/app. Yes, because '..' is a hardlink to the parent directory, and 'cd' does not know how you got to ~/shared/config so it does not know anything about the softlink used to get theere. Bummer... I've just dug through man ln, and don't see any obvious solution. Since this must be a problem for anyone who wants to do something like this, I guess I am taking the wrong approach, altogether. Will have to re-think this smell of burning rubber commences... -- John -- Insert your favourite quote here. Erik Trulsson ertr1...@student.uu.se ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: links vs real directories
2009/3/16 John Almberg jalmb...@identry.com: On Mar 16, 2009, at 11:39 AM, Erik Trulsson wrote: On Mon, Mar 16, 2009 at 11:22:13AM -0400, John Almberg wrote: I always thought that links to real directories were pretty much the same as real directories, but I've just discovered a situation where they are not and I'm wondering if I'm doing something wrong... A *soft* link to a directory entry (be it a directory or a file or something else) is not quite equivalent to the original entry since they are easily distinguished and some programs do treat softlinks differently from other targets. I can see that, now... If I create a soft link to ~/shared/config, and then cd into the directory, when I type 'ls ..', I get the listing for ~/shared, not ~/app. Bummer... I've just dug through man ln, and don't see any obvious solution. Since this must be a problem for anyone who wants to do something like this, I guess I am taking the wrong approach, altogether. Will have to re-think this smell of burning rubber commences... -- John ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org When we're talking in a technical sense, we should probably use the correct terms. The 'official' and more descriptive name for a softlink is a symbolic link. Symbolic links are an absolute nightmare for security purposes, and many programs (especially ones set to run suid) choke on them. This could be intentional Since RoR is free software, you could dive in and edit where it looks for in the source code, or look for a compile-time option. Try /dir/to/port's/work/directory # ./configure --help Chris -- R $h ! $- ! $+ $@ $2 @ $1 .UUCP. (sendmail.cf) ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: links vs real directories
In response to John Almberg jalmb...@identry.com:
A little more information on this... from the Rails log, I can see
that a Ruby script in the config directory cannot load ('require') a
needed file because it can't find it:
/usr/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in
`gem_original_require': no such file to load -- application
(MissingSource File)
It looks like this require statement is using a relative path, like
'../path/to/file'. Does '..' not work properly with a soft link? In
other words, '..', should mean ~/app, but since the config directory
is really in '~/shared', perhaps '..' translates to '~/shared'? That
would cause the problem finding the file.
That's a common problem with soft links and interpreted languages.
Is there a way around this problem?
Generally, you have to fix this in the application itself. I'm not a
Ruby expert, but I can list some of the methods that solve the problem
in PHP:
1 If Ruby has a config value for including library files (often called a
search path), configure it to the correct paths and tell Ruby to
include the file name with the configured path information.
2 Write a wrapper around the requirement function that normalizes the path
so that it works.
3 Ditch the softlink altogether and require files by absolute path.
The first one is probably the most desirable, although I've had good
success using PHP's __autoload() to accomplish #2. Don't know if there's
an equivalent in Ruby.
In any event, if you're explicitly including files by relative path, you'll
have to stop doing that. It's a bad idea in any event.
--
Bill Moran
http://www.potentialtech.com
http://people.collaborativefusion.com/~wmoran/
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Re: links vs real directories
drwxr-xr-x 4 master master 512 Mar 16 11:06 db etc... So, I guess a link is NOT exactly equivalent to a directory. At least not the way I am doing it. I'm guessing I'm making a real newbie mistake, so if anyone can set me straight, I'd appreciate it. IMHO you did everything properly, this program must actually check if it's link. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
