mirror of
https://github.com/moparisthebest/curl
synced 2024-10-31 15:45:12 -04:00
87 lines
3.9 KiB
Plaintext
87 lines
3.9 KiB
Plaintext
License Mixing with apps, libcurl and Third Party Libraries
|
|
===========================================================
|
|
|
|
libcurl can be built to use a fair amount of various third party libraries,
|
|
libraries that are written and provided by other parties that are distributed
|
|
using their own licenses. Even libcurl itself contains code that may cause
|
|
problems to some. This document attempts to describe what licenses libcurl and
|
|
the other libraries use and what possible dilemmas linking and mixing them all
|
|
can lead to for end users.
|
|
|
|
I am not a lawyer and this is not legal advice!
|
|
|
|
One common dilemma is that GPL[1]-licensed code is not allowed to be linked
|
|
with code licensed under the Original BSD license (with the announcement
|
|
clause, unless there's a specified exception in the GPL-licensed module). You
|
|
may still build your own copies that use them all, but distributing them as
|
|
binaries would be to violate the GPL license - unless you accompany your
|
|
license with an exception[2]. This particular problem was addressed when the
|
|
Modified BSD license was created, which does not have the annoncement clause
|
|
that collides with GPL.
|
|
|
|
libcurl http://curl.haxx.se/docs/copyright.html
|
|
|
|
Uses an MIT (or Modified BSD)-style license that is as liberal as
|
|
possible. Some of the source files that deal with KRB4 have Original
|
|
BSD-style announce-clause licenses. You may not distribute binaries
|
|
with krb4-enabled libcurl that also link with GPL-licensed code!
|
|
|
|
OpenSSL http://www.openssl.org/source/license.html
|
|
|
|
Uses an Original BSD-style license with an announement clause that
|
|
makes it "incompatible" with GPL. You are not allowed to ship binaries
|
|
that link with OpenSSL that includes GPL code (unless that specific
|
|
GPL code includes an exception for OpenSSL - a habit that is growing
|
|
more and more common).
|
|
|
|
c-ares http://daniel.haxx.se/projects/c-ares/license.html
|
|
|
|
Uses an MIT license that is very liberal and imposes no restrictions
|
|
on any other library or part you may link with.
|
|
|
|
zlib http://www.gzip.org/zlib/zlib_license.html
|
|
|
|
Uses an MIT-style license that shouldn't collide with any other
|
|
library.
|
|
|
|
krb4
|
|
|
|
While nothing in particular says that a Kerberos4 library must use any
|
|
particular license, the one I've tried and used successfully so far
|
|
(kth-krb4) is Original BSD-licensed with the announcement clause. Some
|
|
of the code in libcurl that is written to deal with Kerberos4 likewise
|
|
have such a license.
|
|
|
|
GSSAPI
|
|
|
|
While nothing in particular says that a GSS/Kerberos5 library must use
|
|
any particular license, the one I've used (Heimdal) is Original BSD-
|
|
licensed with the announcement clause.
|
|
|
|
fbopenssl
|
|
|
|
Unclear license. Based on its name, I assume that it uses the OpenSSL
|
|
license and thus shares the same issues as described for OpenSSL
|
|
above.
|
|
|
|
libidn http://www.gnu.org/licenses/lgpl.html
|
|
|
|
Uses the GNU Lesser General Public License. LGPL is a variation of GPL
|
|
with slightly less aggressive "copyleft". This license requires more
|
|
requirements to be met when distributing binaries, see the license for
|
|
details. Also note that if you distribute a binary that includes this
|
|
library, you must also include the full LGPL license text. Please
|
|
properly point out what parts of the distributed package that the
|
|
license addresses.
|
|
|
|
OpenLDAP http://www.openldap.org/software/release/license.html
|
|
|
|
Uses a Modified BSD-style license. Since libcurl uses OpenLDAP as a
|
|
shared library only, I have not heard of anyone that ships OpenLDAP
|
|
linked with libcurl in an app.
|
|
|
|
|
|
[1] = GPL - GNU General Public License: http://www.gnu.org/licenses/gpl.html
|
|
[2] = http://www.fsf.org/licenses/gpl-faq.html#GPLIncompatibleLibs details on
|
|
how to write such an exception to the GPL
|