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author | Andrii Nakryiko <andrii@kernel.org> | 2022-02-11 21:57:32 -0800 |
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committer | Alexei Starovoitov <ast@kernel.org> | 2022-02-15 09:59:01 -0800 |
commit | bb8ffe61ea454a565e4fb1f450ef71237c9f032c (patch) | |
tree | 6053c062a6eb0afa2162a841e084f64a3328c114 /tools/bpf | |
parent | d3b0b80064e0416850f818184b8f7bba9fdf8c40 (diff) | |
download | linux-bb8ffe61ea454a565e4fb1f450ef71237c9f032c.tar.bz2 |
bpftool: Add C++-specific open/load/etc skeleton wrappers
Add C++-specific static methods for code-generated BPF skeleton for each
skeleton operation: open, open_opts, open_and_load, load, attach,
detach, destroy, and elf_bytes. This is to facilitate easier C++
templating on top of pure C BPF skeleton.
In C, open/load/destroy/etc "methods" are of the form
<skeleton_name>__<method>() to avoid name collision with similar
"methods" of other skeletons withint the same application. This works
well, but is very inconvenient for C++ applications that would like to
write generic (templated) wrappers around BPF skeleton to fit in with
C++ code base and take advantage of destructors and other convenient C++
constructs.
This patch makes it easier to build such generic templated wrappers by
additionally defining C++ static methods for skeleton's struct with
fixed names. This allows to refer to, say, open method as `T::open()`
instead of having to somehow generate `T__open()` function call.
Next patch adds an example template to test_cpp selftest to demonstrate
how it's possible to have all the operations wrapped in a generic
Skeleton<my_skeleton> type without explicitly passing function references.
An example of generated declaration section without %1$s placeholders:
#ifdef __cplusplus
static struct test_attach_probe *open(const struct bpf_object_open_opts *opts = nullptr);
static struct test_attach_probe *open_and_load();
static int load(struct test_attach_probe *skel);
static int attach(struct test_attach_probe *skel);
static void detach(struct test_attach_probe *skel);
static void destroy(struct test_attach_probe *skel);
static const void *elf_bytes(size_t *sz);
#endif /* __cplusplus */
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220212055733.539056-2-andrii@kernel.org
Diffstat (limited to 'tools/bpf')
-rw-r--r-- | tools/bpf/bpftool/gen.c | 24 |
1 files changed, 22 insertions, 2 deletions
diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c index 6f2e20be0c62..022f30490567 100644 --- a/tools/bpf/bpftool/gen.c +++ b/tools/bpf/bpftool/gen.c @@ -831,6 +831,16 @@ static int do_skeleton(int argc, char **argv) codegen("\ \n\ + \n\ + #ifdef __cplusplus \n\ + static struct %1$s *open(const struct bpf_object_open_opts *opts = nullptr);\n\ + static struct %1$s *open_and_load(); \n\ + static int load(struct %1$s *skel); \n\ + static int attach(struct %1$s *skel); \n\ + static void detach(struct %1$s *skel); \n\ + static void destroy(struct %1$s *skel); \n\ + static const void *elf_bytes(size_t *sz); \n\ + #endif /* __cplusplus */ \n\ }; \n\ \n\ static void \n\ @@ -1025,9 +1035,19 @@ static int do_skeleton(int argc, char **argv) \"; \n\ } \n\ \n\ - #endif /* %s */ \n\ + #ifdef __cplusplus \n\ + struct %1$s *%1$s::open(const struct bpf_object_open_opts *opts) { return %1$s__open_opts(opts); }\n\ + struct %1$s *%1$s::open_and_load() { return %1$s__open_and_load(); } \n\ + int %1$s::load(struct %1$s *skel) { return %1$s__load(skel); } \n\ + int %1$s::attach(struct %1$s *skel) { return %1$s__attach(skel); } \n\ + void %1$s::detach(struct %1$s *skel) { %1$s__detach(skel); } \n\ + void %1$s::destroy(struct %1$s *skel) { %1$s__destroy(skel); } \n\ + const void *%1$s::elf_bytes(size_t *sz) { return %1$s__elf_bytes(sz); } \n\ + #endif /* __cplusplus */ \n\ + \n\ + #endif /* %2$s */ \n\ ", - header_guard); + obj_name, header_guard); err = 0; out: bpf_object__close(obj); |