Source definition -- both in GPLv2 and GPLv3 -- has not been typically

read to include the compiler itself, but rather things like makefiles,

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 \textit{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

compliance.  Accused violators should respond very promptly to the

initial request.  As the process continues, violators should follow up weekly with the

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}

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}

\item {\bf Compliance on all Free Software copyrights}.  Copyright holders of Free Software

  often want a company to demonstrate compliance for all GPL'd software in

  a distribution, not just their own.  A copyright holder may refuse to

  reinstate your right to distribute one program unless and until you

\item {\bf Notification to past recipients}.  Users to whom you previously

  distributed non-compliant software should receive a communication

  (email, letter, bill insert, etc.) indicating the violation, describing

  distribution.  If a customer list does not exist (such as in reseller

  situations), an alternative form of notice may be required (such as a

  magazine advertisement).

\item {\bf Appointment of a GPL Compliance Officer.}  The software freedom community

  values personal accountability when things go wrong.  Copyright holders

  often require that you name someone within the violating company

  individual serve as the key public contact for the community when

  compliance concerns arise.

\item {\bf Periodic Compliance Reports.}  Many copyright holders wish to

  monitor future compliance for some period of time after the violation.

  For some period, your company may be required to send regular reports on

  how many distributions of binary and source have occurred.

\end{itemize}

These are just a few possible requirements for reinstatement.  In the

context of a GPL violation, and particularly under v2's termination

provision, the copyright holder may have a range of requests in exchange

for reinstatement of rights.  These software developers are talented

professionals from whose work your company has benefited.  Indeed, you are

unlikely to find a better value or more generous license terms for similar

software elsewhere.  Treat the copyright holders with the same respect you

treat your corporate partners and collaborators.

\chapter{Special Topics in Compliance}

There are several other issues that are less common, but also relevant in

a GPL compliance situation.  To those who face them, they tend to be of

particular interest.

\section{LGPL Compliance}

\label{lgpl}

GPL compliance and LGPL compliance mostly involve the same issues.  As we

discussed in \S~\ref{derivative-works}, questions of modified versions of

software are highly fact-dependant and cannot be easily addressed in any

overview document.  The LGPL adds some additional complexity to the

analysis.  Namely, the various LGPL versions permit proprietary licensing

of certain types of modified versions.  These issues are well beyond the

scope of this document, but as a rule of thumb, once you have determined

(in accordance with LGPLv3) what part of the work is the ``Application''

and what portions of the source are ``Minimal Corresponding Source'', then

you can usually proceed to follow the GPL compliance rules that we

discussed, replacing our discussion of ``Corresponding Source'' with

``Minimal Corresponding Source''.

LGPL also requires that you provide a mechanism to combine the Application

with a modified version of the library, and outlines some options for

this.  Also, the license of the whole work must permit ``reverse

engineering for debugging such modifications'' to the library.  Therefore,

you should take care that the EULA used for the Application does not

contradict this permission.

\section{Upstream Providers}

\label{upstream}

With ever-increasing frequency, software development (particularly for

embedded devices) is outsourced to third parties.  If you rely on an

upstream provider for your software, note that you \emph{cannot ignore

  your GPL compliance requirements} simply because someone else packaged

the software that you distribute.  If you redistribute GPL'd software

(which you do, whenever you ship a device with your upstream's software in

it), you are bound by the terms of the GPL\@.  No distribution (including

redistribution) is permissible absent adherence to the license terms.

Therefore, you should introduce a due diligence process into your software

acquisition plans.  This is much like the software-oriented

recommendations we make in \S~\ref{best-practices}.  Implementing

practices to ensure that you are aware of what software is in your devices

can only improve your general business processes.  You should ask a clear

list of questions of all your upstream providers and make sure the answers

are complete and accurate.  The following are examples of questions you

should ask:

\begin{itemize}

\item What are all the licenses that cover the software in this device?

\item From which upstream vendors, be they companies or individuals, did

  \emph{you} receive your software from before distributing it to us?

\item What are your GPL compliance procedures?

\item If there is GPL'd software in your distribution, we will be

  redistributors of this GPL'd software.  What mechanisms do you have in

  place to aid us with compliance?

\item If we follow your recommended compliance procedures, will you

  formally indemnify us in case we are nonetheless found to be in

  violation of the GPL?

\end{itemize}

This last point is particularly important.  Many GPL enforcements are

escalated because of petty finger-pointing between the distributor and its

upstream.  In our experience, agreements regarding GPL compliance issues

and procedures are rarely negotiated up front.  However, when they are,

violations are resolved much more smoothly (at least from the point of

view of the redistributor).

Consider the cost of potential violations in your acquisition process.

Using Free Software allows software vendors to reduce costs significantly, but be

wary of vendors who have done so without regard for the licenses.  If your

vendor's costs seem ``too good to be true,'' you may ultimately bear the

burden of the vendor's inattention to GPL compliance.  Ask the right

questions, demand an account of your vendors' compliance procedures, and

seek indemnity from them.

\section{User Products and Installation Information}

\label{user-products}

GPLv3 requires you to provide ``Installation Information'' when v3

software is distributed in a ``User Product.''  During the drafting of v3,

the debate over this requirement was contentious.  However, the provision

as it appears in the final license is reasonable and easy to understand.

If you put GPLv3'd software into a User Product (as defined by the

license) and \emph{you} have the ability to install modified versions onto

that device, you must provide information that makes it possible for the

user to install functioning, modified versions of the software.  Note that

if no one, including you, can install a modified version, this provision

does not apply.  For example, if the software is burned onto an

non-field-upgradable ROM chip, and the only way that chip can be upgraded

is by producing a new one via a hardware factory process, then it is

acceptable that the users cannot electronically upgrade the software

themselves.

Furthermore, you are permitted to refuse support service, warranties, and

software updates to a user who has installed a modified version.  You may

even forbid network access to devices that behave out of specification due

to such modifications.  Indeed, this permission fits clearly with usual

industry practice.  While it is impossible to provide a device that is

completely unmodifiable\footnote{Consider that the iPhone, a device

  designed primarily to restrict users' freedom to modify it, was unlocked

  and modified within 48 hours of its release.}, users are generally on