build: symlink drivers to library directory

With the introduction of bus drivers, we now have a situation where
driver libraries will start to depend upon each other. Because of this,
the driver libs need to be discoverable by the dynamic loader.

There are three options to fix this:
1. Force the user to put the $libdir/dpdk/drivers folder into their
	library path.
2. Move all libraries from drivers sub-directory to $libdir.
3. Symlink all libraries from the subfolder to the main library dir.

Option 1 is not great for usability or distro packaging, and option 2
means that we can't have EAL load all drivers from a known path
automatically (as it would error out on non-PMD libs), so option 3 was
chosen as the best fix. The only downside is that on a "ninja uninstall"
the symlinks are not removed, as they are unknown to meson/ninja.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Luca Boccassi <bluca@debian.org>

MAINTAINERS

@@ -79,6 +79,7 @@ F: lib/librte_eal/bsdapp/BSDmakefile.meson
 F: meson_options.txt
 F: config/rte_config.h
 F: buildtools/gen-pmdinfo-cfile.sh
+F: buildtools/symlink-drivers-solibs.sh
 
 ABI versioning
 M: Neil Horman <nhorman@tuxdriver.com>

buildtools/symlink-drivers-solibs.sh

@@ -0,0 +1,41 @@
+#! /bin/sh
+
+#   BSD LICENSE
+#
+#   Copyright(c) 2017 Intel Corporation.
+#   All rights reserved.
+#
+#   Redistribution and use in source and binary forms, with or without
+#   modification, are permitted provided that the following conditions
+#   are met:
+#
+#     * Redistributions of source code must retain the above copyright
+#       notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above copyright
+#       notice, this list of conditions and the following disclaimer in
+#       the documentation and/or other materials provided with the
+#       distribution.
+#     * Neither the name of Intel Corporation nor the names of its
+#       contributors may be used to endorse or promote products derived
+#       from this software without specific prior written permission.
+#
+#   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+#   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+#   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+#   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+#   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+#   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+#   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+#   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+#   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+#   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+#   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+# post-install script for meson/ninja builds to symlink the PMDs stored in
+# $libdir/dpdk/drivers/ to $libdir. This is needed as some PMDs depend on
+# others, e.g. PCI device PMDs depending on the PCI bus driver.
+
+# parameters to script are paths relative to install prefix:
+# 1. directory containing driver files e.g. lib64/dpdk/drivers
+# 2. directory for installed regular libs e.g. lib64
+ln -sf ${DESTDIR}/${MESON_INSTALL_PREFIX}/$1/* ${DESTDIR}/${MESON_INSTALL_PREFIX}/$2

meson.build

@@ -77,6 +77,13 @@ configure_file(output: build_cfg,
 # them.
 dpdk_drivers = ['-Wl,--whole-archive'] + dpdk_drivers + ['-Wl,--no-whole-archive']
 
+# driver .so files often depend upon the bus drivers for their connect bus,
+# e.g. ixgbe depends on librte_bus_pci. This means that the bus drivers need
+# to be in the library path, so symlink the drivers from the main lib directory.
+meson.add_install_script('buildtools/symlink-drivers-solibs.sh',
+		driver_install_path,
+		get_option('libdir'))
+
 pkg = import('pkgconfig')
 pkg.generate(name: meson.project_name(),
 	filebase: 'lib' + meson.project_name().to_lower(),