build scripts, and packaging scripts.

Nonetheless, in the interest of goodwill and the spirit of the GPL, most

companies do provide the compiler itself when they are able, particularly

when the compiler is based on GCC\@ or another copylefted compiler.  If you have

a GCC-based system, it is your prerogative to redistribute that GCC

version (binaries plus sources) to your customers.  We in the software freedom

community encourage you to do this, since it often makes it easier for

users to exercise their software freedom.  However, if you chose to take

this recommendation, ensure that your GCC distribution is itself

compliant.

If you have used a proprietary, third-party compiler to build the

software, then you probably cannot ship it to your customers.  We consider

the name of the compiler, its exact version number, and where it can be

acquired as information that \emph{must} be provided as part of the

Corresponding Source.  This information is essential to anyone who wishes

to produce a binary.  It is not the intent of the GPL to require you to

distribute third-party software tools to your customer (provided the tools

themselves are not based on the GPL'd software shipped), but we do believe

it requires that you give the user all the essential non-proprietary facts

that you had at your disposal to build the software.  Therefore, if you

choose not to distribute the compiler, you should include a {\sc readme}

about where you got it, what version it was, and who to contact to acquire

it, regardless of whether your compiler is Free Software, proprietary, or

internally developed.

\section{Best Practices and Corresponding Source}

\S~\ref{best-practices} and \S~\ref{corresponding-source} above are

closely related.  If you follow the best practices outlined above, you

will find that preparing your Corresponding Source release is an easier

task, perhaps even a trivial one.

Indeed, the enforcement process itself has historically been useful to

software development teams.  Development on a deadline can lead

organizations to cut corners in a way that negatively impacts its

development processes.  We have frequently been told by violators that

they experience difficulty when determining the exact source for a binary

in production (in some cases because their ``build guru'' quit during the

release cycle).  When management rushes a development team to ship a

release, they are less likely to keep release sources tagged and build

systems well documented.

We suggest that, if contacted about a violation, product builders use GPL

enforcement as an opportunity to improve their development practices.  No

developer would argue that their system is better for having a mysterious

build system and no source tracking.  Address these issues by installing a

revision system, telling your developers to use it, and requiring your

build guru to document his or her work!

\chapter{When The Letter Comes}

Unfortunately, many GPL violators ignore their obligations until they are

contacted by a copyright holder or the lawyer of a copyright holder.  You

should certainly contact your own lawyer if you have received a letter

alleging that you have infringed copyrights that were licensed to you

under the GPL\@.  This section outlines a typical enforcement case and

provides some guidelines for response.  These discussions are

generalizations and do not all apply to every alleged violation.

\section{Understanding Who's Enforcing}

\label{compliance-understanding-whos-enforcing}

% FIXME-LATER: this text needs work.

Both  FSF and Conservancy has, as part their mission,  to spread software

freedom. When FSF or Conservancy

enforces GPL, the goal is to bring the violator back into compliance as

quickly as possible, and redress the damage caused by the violation.

That is FSF's steadfast position in a violation negotiation --- comply

with the license and respect freedom.

However, other entities who do not share the full ethos of software freedom

as institutionalized by FSF pursue GPL violations differently.  Oracle, a

company that produces the GPL'd MySQL database, upon discovering GPL

violations typically negotiates a proprietary software license separately for

a fee.  While this practice is not one that FSF nor Conservancy would ever

consider undertaking or even endorsing, it is a legally way for copyright

holders to proceed.

Generally, GPL enforcers come in two varieties.  First, there are

Conservancy, FSF, and other ``community enforcers'', who primary seek the

policy goals of GPL (software freedom), and see financial compensation as

ultimately secondary to those goals.  Second, there are ``for-profit

enforcers'' who use the GPL as a either a crippleware license, or sneakily

induce infringement merely to gain proprietary licensing revenue.

Note that the latter model \texit{only} works for companies who hold 100\% of

the copyrights in the infringed work.  As such, multi-copyright-held works

are fully insulated from these tactics.

\section{Communication Is Key}

GPL violations are typically only escalated when a company ignores the

copyright holder's initial communication or fails to work toward timely

copyright holders to make sure everyone agrees on targets and deadlines

for resolving the situation.

Ensure that any staff who might receive communications regarding alleged

GPL violations understands how to channel the communication appropriately

within your organization.  Often, initial contact is addressed for general

correspondence (e.g., by mail to corporate headquarters or by e-mail to

general informational or support-related addresses).  Train the staff that

processes such communications to escalate them to someone with authority

to take action.  An unknowledgable response to such an inquiry (e.g., from

a first-level technical support person) can cause negotiations to fail

prematurely.

Answer promptly by multiple means (paper letter, telephone call, and

email), even if your response merely notifies the sender that you are

investigating the situation and will respond by a certain date.  Do not

let the conversation lapse until the situation is fully resolved.

Proactively follow up with synchronous communication means to be sure

communications sent by non-reliable means (such as email) were received.

Remember that the software freedom community generally values open communication and

cooperation, and these values extend to GPL enforcement.  You will

generally find that software freedom developers and their lawyers are willing to

have a reasonable dialogue and will work with you to resolve a violation

once you open the channels of communication in a friendly way.

\section{Termination}

Many redistributors overlook GPL's termination provision (GPLv2~\S~4 and

GPLv3~\S~8).  Under v2, violators forfeit their rights to redistribute and

modify the GPL'd software until those rights are explicitly reinstated by

the copyright holder.  In contrast, v3 allows violators to rapidly resolve

some violations without consequence.

If you have redistributed an application under GPLv2\footnote{This applies

  to all programs licensed to you under only GPLv2 (``GPLv2-only'').

  However, most so-called GPLv2 programs are actually distributed with

  permission to redistribute under GPLv2 \emph{or any later version of the

    GPL} (``GPLv2-or-later'').  In the latter cases, the redistributor can

  choose to redistribute under GPLv2, GPLv3, GPLv2-or-later or even

  GPLv3-or-later.  Where the redistributor has chosen v2 explicitly, the

  v2 termination provision will always apply.  If the redistributor has

  chosen v3, the v3 termination provision will always apply.  If the

  redistributor has chosen GPLv2-or-later, then the redistributor may want

  to narrow to GPLv3-only upon violation, to take advantage of the

  termination provisions in v3.}, but have violated the terms of GPLv2,

you must request a reinstatement of rights from the copyright holders

before making further distributions, or else cease distribution and

modification of the software forever.  Different copyright holders

condition reinstatement upon different requirements, and these

requirements can be (and often are) wholly independent of the GPL\@.  The

terms of your reinstatement will depend upon what you negotiate with the

copyright holder of the GPL'd program.

Since your rights under GPLv2 terminate automatically upon your initial

violation, \emph{all your subsequent distributions} are violations and

infringements of copyright.  Therefore, even if you resolve a violation on

your own, you must still seek a reinstatement of rights from the copyright

holders whose licenses you violated, lest you remain liable for

infringement for even compliant distributions made subsequent to the

initial violation.

GPLv3 is more lenient.  If you have distributed only v3-licensed programs,

you may be eligible under v3~\S~8 for automatic reinstatement of rights.

You are eligible for automatic reinstatement when:

\begin{itemize}

\item you correct the violation and are not contacted by a copyright

  holder about the violation within sixty days after the correction, or

\item you receive, from a copyright holder, your first-ever contact

  regarding a GPL violation, and you correct that violation within thirty

  days of receipt of copyright holder's notice.

\end{itemize}

In addition to these permanent reinstatements provided under v3, violators

who voluntarily correct their violation also receive provisional

permission to continue distributing until they receive contact from the

copyright holder.  If sixty days pass without contact, that reinstatement

becomes permanent.  Nonetheless, you should be prepared to cease

distribution during those initial sixty days should you receive a

termination notice from the copyright holder.

Given that much discussion of v3 has focused on its so-called more

complicated requirements, it should be noted that v3 is, in this regard,

more favorable to violators than v2.

\chapter{Standard Requests}

As we noted above, different copyright holders have different requirements

for reinstating a violator's distribution rights.  Upon violation, you no

longer have a license under the GPL\@.  Copyright holders can therefore

set their own requirements outside the license before reinstatement of

rights.  We have collected below a list of reinstatement demands that

copyright holders often require.

\begin{itemize}