Ideas for changes to Unix filesystem

[Richard M. Mathews]

barmar at think.com (Barry Margolin) writes:

>In article <richard.665896415 at fafnir.la.locus.com> richard at locus.com (Richard M. Mathews) writes:
>>With link() you have a pathname to the file, so you have some idea where
>>you can put the new link().  Presumably with flink(), you are using this
>>call because you DON'T have a pathname.  Since you don't know where the
>>file came from, you have to do more work to figure out where it can go.

>What do pathnames have to do with "where you can put the new link"?  You
>can put the new link anywhere on the same file system as the file.  Due to
>symbolic links, it is not possible to determine whether two files are on
>the same file system simply by looking at the pathnames.

>Presumably one of the first things that the link() system call does is

I get the feeling that you thought I meant that the flink system call
wouldn't be able to figure out where the link is allowed to go.  That
isn't what I meant at all.  The "you" in my quote above refers to
application programs which try to make general use of flink on a random
file descriptor.  I meant that a possible application of flink would NOT
include a general purpose program which would flink its stdin to some file
to allow it to reopen the file in a different mode (e.g., "more" wants to
read stderr (at least it did at one time), so if it gets a stderr which
is open for write-only, it might want an opportunity to reopen the file
(terminal) for read-write).  This would not be a practical use of flink
because of the single file system restriction of link and flink.

On the other hand, a program which knows where a file is because it
created it (and thus it also knows that the original path name was not
through a symbolic link) can make good use of flink to put back a file
even after the link count goes to zero.

Sorry, if I wasn't clear before.

Richard M. Mathews			D efend
richard at locus.com			 E stonian-Latvian-Lithuanian
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