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DBI-1.654
⭐ Starred 84 / DBD::Gofer::Transport::Base
Security Advisories (2)
CVE-2026-108518 (2026-10-20)

DBI versions before 1.656 for Perl crash via type confusion in dbi_profile when a database handle is destroyed under a Profile Path with an {attr} element. An {attr} element names a database handle attribute, which dbi_profile reads from the handle's inner hash. It expects the inner handle as a reference and dereferences it, but a handle that is being destroyed hands back the inner hash itself, so the dereference yields the hash's bucket array. A type check on that pointer usually fails and the call goes unprofiled. When the memory it addresses passes the check, the attribute lookup dereferences a NULL or invalid pointer and the process dies on SIGSEGV. The Path is set by the application, by the Profile handle attribute, or by the DBI_PROFILE environment variable, so `DBI_PROFILE={ImplementorClass}` can crash an unmodified program.

CVE-2026-111879 (2026-10-20)

DBI versions before 1.656 for Perl hang on a later open of a DBD::DBM table because a failed open_data does not release the table's lock. open_data creates the table's lock file and takes an exclusive flock on it for a CREATE, before the checks that can croak: a dbm_mldbm value that is not a module name, a failing tie, or a missing data file. The croak unwinds before the table object is blessed, so nothing releases the lock, and the meta data holding the open descriptor stays cached on the database handle. The dbm_mldbm and dbm_type values come from the DSN or the connect attributes, so a caller that chooses the serializer or the storage backend can trigger the failure. The flock has no timeout, so a later open of that table (even through a separate database handle) blocks for as long as the handle holding the stale lock lives, in the same process or any other.

NAME

DBD::Gofer::Transport::Base - base class for DBD::Gofer client transports

SYNOPSIS

my $remote_dsn = "..."
DBI->connect("dbi:Gofer:transport=...;url=...;timeout=...;retry_limit=...;dsn=$remote_dsn",...)

or, enable by setting the DBI_AUTOPROXY environment variable:

export DBI_AUTOPROXY='dbi:Gofer:transport=...;url=...'

which will force all DBI connections to be made via that Gofer server.

DESCRIPTION

This is the base class for all DBD::Gofer client transports.

ATTRIBUTES

Gofer transport attributes can be specified either in the attributes parameter of the connect() method call, or in the DSN string. When used in the DSN string, attribute names don't have the go_ prefix.

go_dsn

The full DBI DSN that the Gofer server should connect to on your behalf.

When used in the DSN it must be the last element in the DSN string.

go_timeout

A time limit for sending a request and receiving a response. Some drivers may implement sending and receiving as separate steps, in which case (currently) the timeout applies to each separately.

If a request needs to be resent then the timeout is restarted for each sending of a request and receiving of a response.

go_retry_limit

The maximum number of times an request may be retried. The default is 2.

go_retry_hook

This subroutine reference is called, if defined, for each response received where $response->err is true.

The subroutine is pass three parameters: the request object, the response object, and the transport object.

If it returns an undefined value then the default retry behaviour is used. See "RETRY ON ERROR" below.

If it returns a defined but false value then the request is not resent.

If it returns true value then the request is resent, so long as the number of retries does not exceed go_retry_limit.

RETRY ON ERROR

The default retry on error behaviour is:

- Retry if the error was due to DBI_GOFER_RANDOM. See L<DBI::Gofer::Execute>.

- Retry if $request->is_idempotent returns true. See L<DBI::Gofer::Request>.

A retry won't be allowed if the number of previous retries has reached go_retry_limit.

TRACING

Tracing of gofer requests and responses can be enabled by setting the DBD_GOFER_TRACE environment variable. A value of 1 gives a reasonably compact summary of each request and response. A value of 2 or more gives a detailed, and voluminous, dump.

The trace is written using DBI->trace_msg() and so is written to the default DBI trace output, which is usually STDERR.

METHODS

This section is currently far from complete.

response_retry_preference

$retry = $transport->response_retry_preference($request, $response);

The response_retry_preference is called by DBD::Gofer when considering if a request should be retried after an error.

Returns true (would like to retry), false (must not retry), undef (no preference).

If a true value is returned in the form of a CODE ref then, if DBD::Gofer does decide to retry the request, it calls the code ref passing $retry_count, $retry_limit. Can be used for logging and/or to implement exponential back-off behaviour. Currently the called code must return using return; to allow for future extensions.

AUTHOR

Tim Bunce, http://www.tim.bunce.name

LICENCE AND COPYRIGHT

Copyright (c) 2007-2008, Tim Bunce, Ireland. All rights reserved.

This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See perlartistic.

SEE ALSO

DBD::Gofer, DBI::Gofer::Request, DBI::Gofer::Response, DBI::Gofer::Execute.

and some example transports:

DBD::Gofer::Transport::stream

DBD::Gofer::Transport::http

DBI::Gofer::Transport::mod_perl