Re: [Firebird-devel] ERROR:operating system directive CreateFile failed

[Mark R. <ma...@la...>]

On 4-10-2012 20:57, Vlad Khorsun wrote:
>> Why does Firebird return such a low level OS-dependent(?) error message
>> instead of returning a Firebird-specific message that explains what went
>> wrong (eg creating temporary files), instead of why it failed (the
>> low-level error message)?
>
> - because it was written this way many years ago (before it became Firebird)
> - because without original lowest-level error it is impossible to find a reason for failure
> - because in most cases it is obvious what Firebird did at failure moment
>
>      I agree that sometime more context from intermediate levels could help to better
> understand what happens. For example, when transliterate error happens it is good
> to know assignment destination (field or variable) name. I'm not sure it is easy to
> implement. But in the case of "CreateFile failed" when index is built... - i see nothing
> to add here, it is clear enough as for me...

I don't: as an 'end-user' of Firebird I have no clue what it means, in 
this case it is not that bad because you also have the message "cannot 
commit index IDX_RMGM_IMPORT_DNA", although an additional explanation 
like "failed to create temporary file" or something would be helpful.

It is worse in other situations: eg trying to connect to a database, or 
creating a new database. This is the message you get when trying to 
connect to a non-existent database on Windows (with flamerobin):

*** IBPP::SQLException ***
Context: Database::Connect
Message: isc_attach_database failed

SQL Message : -902
Unsuccessful execution caused by a system error that precludes 
successful execution of subsequent statements

Engine Code    : 335544344
Engine Message :
I/O error during "CreateFile (open)" operation for file "D:\XYZ.FDB"
Error while trying to open file
Het systeem kan het opgegeven bestand niet vinden.

(The system cannot find the specified file.)
The first time I was confronted with this error message, I thought 
"What, why is it trying to create a file, the database already exists?"

On Linux I get
Engine Code    : 335544344
Engine Message :
I/O error during "open" operation for file "/opt/xyz.fdb"
Error while trying to open file
No such file or directory

"Huh, a a similar, but different error message?"

Now on a DVD-ROM drive that does not contain a disk:

Engine Code    : 335544344
Engine Message :
I/O error during "CreateFile (open)" operation for file "F:\XYZ\XYZ.FDB"
Error while trying to open file
Het apparaat is niet klaar.

(Device is not ready)
Now what happens if I try to connect to the same non-existent database 
with DatabaseAccess = Restrict D:\data\DB:

Engine Code    : 335544831
Engine Message :
Access to database "D:\XYZ.FDB" is denied by server administrator

What would happen when I try to connect to a drive that does not exist 
(eg: drive K:\) (Note: same with or without DatabaseAccess restriction)

SQL Message : -904
Unsuccessful execution caused by an unavailable resource.

Engine Code    : 335544375
Engine Message :
unavailable database

Now with a file that the user has no access to (eg read access is denied 
in the ACL):

Engine Code    : 335544344
Engine Message :
I/O error during "CreateFile (open)" operation for file 
"D:\DATA\DB\TESTDATABASE.FDB"
Error while trying to open file
Toegang geweigerd.

(Access denied)
Firebird is leaking information about the layout of a computer (eg 
existence or non-existence of drives), and about the security 
configuration of both Firebird (DatabaseAccess) and the rights 
configuration on file or folder level.

I would expect and prefer that in all these cases that the error message 
would be the same (eg: "Unable to attach to database '<db>': Database 
does not exist or is not accessible", where <db> is the original alias 
or path used in the connection string, and not the actual path Firebird 
tries).
The actual error details would then be logged in firebird.log. 
Interestingly, of the above attempts to access a non-existent or 
restricted file, nothing(!) is logged in firebird.log.

Mark
-- 
Mark Rotteveel