[libcamera-devel] [PATCH 0/5] Support loading IPAs from the build tree

[Nicolas Dufresne]

Le mardi 11 février 2020 à 17:51 +0200, Laurent Pinchart a écrit :
> Hi Nicolas,
> 
> On Sat, Feb 08, 2020 at 12:54:52PM -0500, Nicolas Dufresne wrote:
> > Le jeudi 06 février 2020 à 22:39 +0200, Laurent Pinchart a écrit :
> > > On Wed, Feb 05, 2020 at 01:49:11PM -0500, Nicolas Dufresne wrote:
> > > > Le mercredi 05 février 2020 à 14:12 +0000, Kieran Bingham a écrit :
> > > > > On 05/02/2020 14:03, Nicolas Dufresne wrote:
> > > > > > Le mer. 5 févr. 2020 08 h 04, Kieran Bingham a écrit :
> > > > > > > When developing and testing libcamera, the usual development model is to
> > > > > > > compile and run one of the test or utility applications.
> > > > > > 
> > > > > > I like it. Be aware that it won't work for me. It only work if the build
> > > > > > path matches run path, which isn't the case when cross compiling and
> > > > > > exporting over NFS. Any suggestion ?
> > > > > 
> > > > > Interesting (and painful) point.
> > > > > 
> > > > > Ideally it would be a relative path, but the binary path
> > > > >  (/proc/self/exe) doesn't always have to stay relative to the library
> > > > > path ...
> > > > > 
> > > > > I wonder if I can get the library path at runtime... Time to dig into
> > > > > what else is in the _DYNAMIC table perhaps.
> > > > > 
> > > > > Otherwise, I'm certainly open to suggestions from the list here ;-)
> > > > 
> > > > Note that meanwhile I can just set the env really, I'm a bit use to that anyway.
> > > > GStreamer, GLib and Mesa (which are the kind of stuff I cross compile) all
> > > > requires few envs already.
> > > 
> > > How about installing libcamera instead of copying binaries ? :-) You can
> > > set the prefix to the path on your target system, and install to your
> > > NFS directory by setting the DESTDIR variable for meson install.
> > 
> > I'm not sure what you refer to with "installing instead of copying
> > binaries" (that sounds like the same thing, as installing requires
> > copying binaries). I'm strictly speaking about running things from
> > build tree here, something we happen to have been doing for more then a
> > decade in the GStreamer project. We use environments though, as your
> > solution isn't portable, we just don't have that luxury to ignore other
> > OS.
> 
> Yes, if you run directly from the build tree, it's an issue not solved
> by this series. But wouldn't it be better in that case to install to the
> NFS root as part of the (cross-)compilation on the host instead of
> running in the build tree ?

In my setup, the build tree is exported over NFS. So on the nfs server,
which is the build server too, I do:

  cd /path/to/nfs/something/gst-build
  ninja -C build

And on the target:
  cd something/gst-build
  ./gst-unisntalled.py --sysroot /path/to/nfs

I've aggregated libcamera to gst-build (it's extensible), but still
need some env specific to libcamera. I tried this patchset, but still
needed the env. Now my setup have no secret anymore ;-D

That in no way invalidate this patch, I think it's really nice for
those testing on host (should work with virtme too).

> 
> > > > > > > IPA modules are loaded by the IPAManager, from a system path, or by
> > > > > > > parsing an environment variable.
> > > > > > > 
> > > > > > > Provide the build path to the library through a temporary storage in the
> > > > > > > runpath of the ELF library strings table.  This entry is stripped at
> > > > > > > install time, but allows us to identify the location of the recently
> > > > > > > compiled IPA modules without the user having to manually declare paths to the
> > > > > > > build system.
> > > > > > > 
> > > > > > > Previously to this series the IPA tests would only be able to be run
> > > > > > > from the root of the build tree, due to the hardcoded path relative to that
> > > > > > > point. Now that the IPAs can be found from their build location, we no longer
> > > > > > > need to provide this hardcoded path through the LIBCAMERA_IPA_MODULE_PATH
> > > > > > > for tests, and as a further consequence they can be run directly without
> > > > > > > requiring the launch to be run from the top level of the build tree.
> > > > > > > 
> > > > > > > Kieran Bingham (5):
> > > > > > >   libcamera: utils: Provide helper to get dynamic library runpath
> > > > > > >   libcamera: ipa_manager: Split path handling
> > > > > > >   libcamera: ipa_manager: Allow recursive parsing
> > > > > > >   libcamera: ipa_manager: Search the runpath for IPA libraries
> > > > > > >   tests: Remove IPA_MODULE_PATH environment variable
> > > > > > > 
> > > > > > >  src/libcamera/include/ipa_manager.h |   5 +-
> > > > > > >  src/libcamera/include/utils.h       |   1 +
> > > > > > >  src/libcamera/ipa_manager.cpp       | 111 ++++++++++++++++++++++------
> > > > > > >  src/libcamera/meson.build           |   1 +
> > > > > > >  src/libcamera/utils.cpp             |  26 +++++++
> > > > > > >  src/meson.build                     |   7 ++
> > > > > > >  test/libtest/test.cpp               |   4 -
> > > > > > >  7 files changed, 126 insertions(+), 29 deletions(-)