build: support drivers symlink on Windows

The symlink-drivers-solibs.sh script was disabled as part of 'install'
for Windows because there is no support for shell scripts. However,
this means that driver related DLLs are not present in the installed
'libdir' directory. Add a python script to perform the install and use
it for Windows if the version of meson supports using an external
program with add_install_script (>= 0.55.0).

On Windows, symbolic links are somewhat problematic since the
SeCreateSymbolicLinkPrivilege is required to be able to create them.
In addition, different cross-compilation environments handle symbolic
links differently, e.g. WSL, Msys2, Cygwin. Rather than trying to
distinguish these scenarios, the python script will perform a file copy
for any Windows specific names.

On Windows, the shared library outputs have different names depending
upon which toolset has been used to build them. The script currently
handles Clang and GCC.

On Linux the functionality is unchanged, but could be replaced with the
python script once the required minimum version of meson is >= 0.55.0.

Cc: stable@dpdk.org

Signed-off-by: Nick Connolly <nick.connolly@mayadata.io>
Tested-by: Narcisa Vasile <navasile@linux.microsoft.com>
Acked-by: Narcisa Vasile <navasile@linux.microsoft.com>
Reviewed-by: Bruce Richardson <bruce.richardson@intel.com>

MAINTAINERS

@@ -105,6 +105,7 @@ F: buildtools/call-sphinx-build.py
 F: buildtools/list-dir-globs.py
 F: buildtools/pkg-config/
 F: buildtools/symlink-drivers-solibs.sh
+F: buildtools/symlink-drivers-solibs.py
 F: devtools/test-meson-builds.sh
 F: devtools/check-meson.py
 

buildtools/symlink-drivers-solibs.py

@@ -0,0 +1,49 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright(c) 2021 Intel Corporation
+
+import os
+import sys
+import glob
+import shutil
+
+# post-install script for meson/ninja builds to symlink the PMDs stored in
+# $libdir/dpdk/pmds-*/ 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 for installed regular libs e.g. lib64
+# 2. subdirectory of libdir where the PMDs are
+# 3. directory for installed regular binaries e.g. bin
+
+os.chdir(os.environ['MESON_INSTALL_DESTDIR_PREFIX'])
+
+lib_dir = sys.argv[1]
+pmd_subdir = sys.argv[2]
+bin_dir = sys.argv[3]
+pmd_dir = os.path.join(lib_dir, pmd_subdir)
+
+# copy Windows PMDs to avoid any issues with symlinks since the
+# build could be a cross-compilation under WSL, Msys or Cygnus.
+# the filenames are dependent upon the specific toolchain in use.
+
+def copy_pmd_files(pattern, to_dir):
+	for file in glob.glob(os.path.join(pmd_dir, pattern)):
+		to = os.path.join(to_dir, os.path.basename(file))
+		shutil.copy2(file, to)
+		print(to + ' -> ' + file)
+
+copy_pmd_files('*rte_*.dll', bin_dir)
+copy_pmd_files('*rte_*.pdb', bin_dir)
+copy_pmd_files('*rte_*.lib', lib_dir)
+copy_pmd_files('*rte_*.dll.a', lib_dir)
+
+# symlink shared objects
+
+os.chdir(lib_dir)
+for file in glob.glob(os.path.join(pmd_subdir, 'librte_*.so*')):
+	to = os.path.basename(file)
+	if os.path.exists(to):
+		os.remove(to)
+	os.symlink(file, to)
+	print(to + ' -> ' + file)

config/meson.build

@@ -59,6 +59,10 @@ eal_pmd_path = join_paths(get_option('prefix'), driver_install_path)
 if not is_windows
     meson.add_install_script('../buildtools/symlink-drivers-solibs.sh',
             get_option('libdir'), pmd_subdir_opt)
+elif meson.version().version_compare('>=0.55.0')
+    # 0.55.0 is required to use external program with add_install_script
+    meson.add_install_script(py3, '../buildtools/symlink-drivers-solibs.py',
+            get_option('libdir'), pmd_subdir_opt, get_option('bindir'))
 endif
 
 # init disable/enable driver lists that will be populated in different places