[rhp@zirx.pair.com: Bug#45581: openFile has questionable error handling]

[Antti-Juhani Kaijanaho]

Here is another bug report from Havoc.  Please take a look at it.

Please CC [EMAIL PROTECTED] on replies (note that the number is
different from the bug report I forwarded yesterday).  I believe you
already know the reasons ;-)

 - ajk

----- Forwarded message from Havoc Pennington <[EMAIL PROTECTED]> -----

Subject: Bug#45581: openFile has questionable error handling 
Reply-To: Havoc Pennington <[EMAIL PROTECTED]>, [EMAIL PROTECTED]
Date: Mon, 20 Sep 1999 09:45:33 -0400 (EDT)
From: Havoc Pennington <[EMAIL PROTECTED]>
To: [EMAIL PROTECTED]


Package: hugs
Version: 98.199905-4

Hi,

This may be a wishlist item, but here goes. Using the same program from
bug 45546 to test:

$ ./replace.lhs foo bar baz
"Failed to open file foo: Illegal operation"
$ 

This should be "No such file or directory"; I get the same thing opening a
file for writing when the error should be "Permission denied."  Looking at
the source code for Hugs, it appears that it always returns the same vague
error in iomonad.c, fopenPrim().  A little switch on errno would allow
Hugs to return the errors given in the Haskell Report (such as
isDoesNotExistError or isPermissionError) and would save users a lot of
time wondering what's going on.

A secondary problem: Hugs seems to have a hard-coded limit of 40 open file
handles in storage.c, openHandle() which is also used by the openFile
function; since Linux allows over 1000 open files, this is a bit limiting.
Also, if you exceed the limit the openHandle function aborts, while for
"real world" programs you should have a chance to recover (errno ==
ENFILE). Suggested fix is to check errno and return a sensible error if
the actual number of descriptors is exceeded. It looks like it will also
be necessary to dynamically size the "handles" table in storage.c.

Thanks,
Havoc



----- End forwarded message -----

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%%% Antti-Juhani Kaijanaho % [EMAIL PROTECTED] % http://www.iki.fi/gaia/ %%%

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                             (John Cage)