From: Julia Kartseva <hex@fb.com>
Date: Sat, 14 Nov 2020 01:08:15 +0000 (-0800)
Subject: meson, bpf: add HAVE_LIBBPF, BPF_FRAMEWORK options
X-Git-Tag: v249-rc1~339^2~13
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7d861e12637892f1fcf7bbd69e4aec5a096f4bcb;p=thirdparty%2Fsystemd.git

meson, bpf: add HAVE_LIBBPF, BPF_FRAMEWORK options

* Add `bpf-framework` feature gate with 'auto', 'true' and 'false' choices
* Add libbpf [0] dependency
* Search for clang llvm-strip and bpftool binaries in compile time to
generate bpf skeleton.

For libbpf [0], make 0.2.0 [1] the minimum required version.
If libbpf is satisfied, set HAVE_LIBBPF config option to 1.

If `bpf-framework` feature gate is set to 'auto', means that whether
bpf feature is enabled or now is defined by the presence of all of
libbpf, clang, llvm and bpftool in build
environment.
With 'auto' all dependencies are optional.
If the gate is set to `true`, make all of the libbpf, clang and llvm
dependencies mandatory.
If it's set to `false`, set `BPF_FRAMEWORK` to false and make libbpf
dependency optional.

libbpf dependency is dynamic followed by the common pattern in systemd.

meson, bpf: add build rule for socket_bind program
---

diff --git a/meson.build b/meson.build
index 81db2d27ab7..93d3c26a22c 100644
--- a/meson.build
+++ b/meson.build
@@ -937,6 +937,25 @@ if not libcap.found()
         libcap = cc.find_library('cap')
 endif
 
+want_bpf_framework = get_option('bpf-framework')
+bpf_framework_required = want_bpf_framework == 'true'
+
+libbpf = dependency('libbpf', required : bpf_framework_required, version : '>= 0.2')
+conf.set10('HAVE_LIBBPF', libbpf.found())
+
+if want_bpf_framework == 'false'
+        conf.set10('BPF_FRAMEWORK', 0)
+else
+        clang = find_program('clang', required : bpf_framework_required)
+        llvm_strip = find_program('llvm-strip', required : bpf_framework_required)
+        bpftool = find_program('bpftool', required : bpf_framework_required)
+        bpf_arches = ['x86_64']
+        deps_found = libbpf.found() and clang.found() and llvm_strip.found() and bpftool.found()
+        # Can build BPF program from source code in restricted C
+        conf.set10('BPF_FRAMEWORK',
+                bpf_arches.contains(host_machine.cpu_family()) and deps_found)
+endif
+
 libmount = dependency('mount',
                       version : fuzzer_build ? '>= 0' : '>= 2.30')
 
@@ -1604,6 +1623,7 @@ conf.set10('ENABLE_EFI', have)
 
 ############################################################
 
+build_bpf_skel_py = find_program('tools/build-bpf-skel.py')
 generate_gperfs = find_program('tools/generate-gperfs.py')
 make_autosuspend_rules_py = find_program('tools/make-autosuspend-rules.py')
 make_directive_index_py = find_program('tools/make-directive-index.py')
@@ -1696,6 +1716,7 @@ install_libsystemd_static = static_library(
                         libxz,
                         libzstd,
                         liblz4,
+                        libbpf,
                         libcap,
                         libblkid,
                         libmount,
@@ -3766,6 +3787,7 @@ foreach tuple : [
         ['elfutils'],
         ['gcrypt'],
         ['gnutls'],
+        ['libbpf'],
         ['libcryptsetup'],
         ['libcurl'],
         ['libfdisk'],
@@ -3792,6 +3814,7 @@ foreach tuple : [
         # components
         ['backlight'],
         ['binfmt'],
+        ['bpf-framework',         conf.get('BPF_FRAMEWORK') == 1],
         ['coredump'],
         ['environment.d'],
         ['efi'],
diff --git a/meson_options.txt b/meson_options.txt
index 9441b88dec5..ad7174cf69e 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -403,3 +403,6 @@ option('kernel-install', type: 'boolean', value: 'true',
        description : 'install kernel-install and associated files')
 option('analyze', type: 'boolean', value: 'true',
        description : 'install systemd-analyze')
+
+option('bpf-framework', type : 'combo', choices : ['auto', 'true', 'false'],
+    description: 'build BPF programs from source code in restricted C')