Add chapter on router with included source CD

Note that this chapter is not properly TeX-formatted.  Some work will
need to be done to make it compile correctly.  It should also be
generally expanded and made to flow more nicely, in the spirit of the
other case study chapters.

enforcement-case-studies.tex

@@ -798,6 +798,107 @@ Linux.  A decade later, this situation remains largely unresolved.
 
 \end{enumerate}
 
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% FIXME: expand title, etc.
+\chapter{ThinkPengiun}
+
+% FIXME
+This case study discusses one the best source code releases we've seen, which
+was provided alongside the ThinkPengiun TPE-NWIFIROUTER.  The method of
+distribution (complete source accompanying the product) and the way the source
+was laid out provide very good examples of how to make things easier for both
+the distributor and the purchaser of the hardware containing GPLed components.
+
+\section{Root Filesystem and Kernel Compilation}
+
+* We found a CD included in the box that the ThinkPenguin TPE-NWIFIROUTER
+  shipped in, labelled "libreCMC v1.2.1 source code".  On the CD, there was a
+  README file at the top level, which mentioned that to build the software, one
+  needed a GNU/Linux system as well as a list of approximately 10 packages.
+  These sorts of plain text instructions are helpful because we know what kind
+  of system we are expected to use, and what commands we should run on it.  Such
+  instructions are not strictly required, as an obviously-named shell script may
+  suffice, but they are helpful in clarifying any ambiguities that may arise.
+* Since the instructions didn't mention a specific distro to use, we ran the
+  build on an amd64 Debian 6 machine we had, after confirming the packages were
+  installed.  In particular, we ran "make", as described in the instructions in
+  the README.  The instructions said that "make menuconfig" could be used to
+  adjust the settings, but it appeared this step was optional ("Please note that
+  the default configuration is what was used to build the firmware image for
+  your router. It is advised that you use this configuration.") so we chose to
+  skip straight to the "make" step instead.  This was done after extracting the
+  librecmc-v1.2.1.tar.bz2 tarball, which was not explicitly spelled out (this
+  should ideally be added to the README), but was implied by the
+  "u-boot_reflash" file (in the same directory as the README), which explicitly
+  used the other tarball.  The build took about 40 minutes to run on our system.
+* It was helpful to know that we could use "make menuconfig" for configuration
+  changes, as being able to modify the source is an important part of the GPL's
+  requirements.  Adding instructions like these shows that the distributor is
+  aware of and interested in promoting the spirit of the GPL, by making it
+  easier to modify the source than may be strictly required by the GPL's text.
+* The "make" step completed successfully on our system and resulted in several
+  files being generated in the bin/ar71xx directory, namely firmware images.
+  There appeared to be several filesystem and kernel images, for different
+  hardware versions.  It was unclear which one to install on the particular
+  device we received or how to install it, both of which should have been
+  mentioned in the README.
+* The above installation issue is mitigated by the availability of a web UI in
+  the product that performs firmware image installation.  It would be best if
+  instructions like those at http://librecmc.org/librecmc/wiki?name=Tp+MR3020
+  were included in the README, as the user cannot be expected to infer that or
+  to find such a link.
+
+\section{U-Boot Compilation}
+
+* As mentioned above, we also found a "u-boot_reflash" file at the top level of
+  the included source CD.  We followed the instructions for compiling U-Boot,
+  which were fairly straight-forward.  One modification would be to mention that
+  "\$U-BOOT_SRC" referred to the extracted source directory, which was implied,
+  but should have been explicit.
+* Additionally, we noticed that the included toolchain binaries, which were used
+  by the U-Boot compilation process by default, did not run on our system.  In
+  particular, we received this error:
+
+mips-librecmc-linux-uclibc-gcc.bin: /lib/libc.so.6: version `GLIBC_2.14' not found (required by mips-librecmc-linux-uclibc-gcc.bin)
+
+* We found that by removing toolchain/bin and symlinking the toolchain built for
+  the filesystem/kernel above in its place, we were able to complete the U-Boot
+  build.  Specifically, we symlinked toolchain/bin to:
+
+  ../../staging_dir/toolchain-mips_34kc_gcc-4.6-linaro_uClibc-0.9.33.2/bin
+
+* Ideally the pre-built toolchain binaries should not be included and a symlink
+  as mentioned above should be created by default, with a mention that the
+  U-Boot build depends on the previous build for its toolchain.
+* After compilation completed successfully, we found a new U-Boot image in the
+  bin directory.  The instructions explained how to install it on the device.
+
+\section{Installation}
+
+% FIXME: add more details once install tests have been completed
+
+\section{Minor Infractions}
+
+As mentioned above, there were a few minor infractions.  These made it slightly
+difficult to complete the build and installation without additional context, but
+did not make the build impossible to complete without more information, such as
+missing source code for kernel modules or depending on a specific cross-compiler
+but not mentioning which one or, better yet, including its source code, which
+are both more problematic infractions.  These minor infractions were:
+
+% FIXME: clarify seriousness of no install instructions; lack of clarity in
+% which version to install could be more problematic
+
+* Not mentioning how to extract the source tarball and then where to run the
+  "make" command.
+* Not mentioning how to install the kernel and root filesystem on the device;
+  this is the biggest of these 3 issues but a bit less troublesome than it would
+  otherwise have been since the web-based firmware update process is well-known.
+* Using pre-built toolchain binaries that don't work on all systems instead of
+  the ones that are built in a separate step, but not moved to the right place.
+
+
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 % COMMENT OUT THIS CHAPTER.
 % FIXME: is this material moot now that we include the compliance guide?