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| author | Alexei Starovoitov <ast@kernel.org> | 2022-02-15 09:59:01 -0800 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2022-02-15 09:59:02 -0800 |
| commit | d2b94f33e43727c17ed2816c1bfa10e6bc4f4be3 (patch) | |
| tree | e0c190cad0dc273b1d371bf8b8d567a9ee657b5e | |
| parent | d3b0b80064e0416850f818184b8f7bba9fdf8c40 (diff) | |
| parent | 189e0ecabc1717db62deab751afa755f07bdbcf8 (diff) | |
| download | net-d2b94f33e43727c17ed2816c1bfa10e6bc4f4be3.tar.gz | |
Merge branch 'Make BPF skeleton easier to use from C++ code'
Andrii Nakryiko says:
====================
Add minimal C++-specific additions to BPF skeleton codegen to facilitate
easier use of C skeletons in C++ applications. These additions don't add any
extra ongoing maintenance and allows C++ users to fit pure C skeleton better
into their C++ code base. All that without the need to design, implement and
support a separate C++ BPF skeleton implementation.
v1->v2:
- use default argument values in T::open() (Alexei).
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
| -rw-r--r-- | tools/bpf/bpftool/gen.c | 24 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/test_cpp.cpp | 87 |
2 files changed, 107 insertions, 4 deletions
diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c index 6f2e20be0c62fb..022f30490567d6 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); diff --git a/tools/testing/selftests/bpf/test_cpp.cpp b/tools/testing/selftests/bpf/test_cpp.cpp index e00201de289012..773f165c4898e9 100644 --- a/tools/testing/selftests/bpf/test_cpp.cpp +++ b/tools/testing/selftests/bpf/test_cpp.cpp @@ -5,18 +5,100 @@ #include <bpf/btf.h> #include "test_core_extern.skel.h" -/* do nothing, just make sure we can link successfully */ +template <typename T> +class Skeleton { +private: + T *skel; +public: + Skeleton(): skel(nullptr) { } + + ~Skeleton() { if (skel) T::destroy(skel); } + + int open(const struct bpf_object_open_opts *opts = nullptr) + { + int err; + + if (skel) + return -EBUSY; + + skel = T::open(opts); + err = libbpf_get_error(skel); + if (err) { + skel = nullptr; + return err; + } + + return 0; + } + + int load() { return T::load(skel); } + + int attach() { return T::attach(skel); } + + void detach() { return T::detach(skel); } + + const T* operator->() const { return skel; } + + T* operator->() { return skel; } + + const T *get() const { return skel; } +}; static void dump_printf(void *ctx, const char *fmt, va_list args) { } +static void try_skeleton_template() +{ + Skeleton<test_core_extern> skel; + std::string prog_name; + int err; + LIBBPF_OPTS(bpf_object_open_opts, opts); + + err = skel.open(&opts); + if (err) { + fprintf(stderr, "Skeleton open failed: %d\n", err); + return; + } + + skel->data->kern_ver = 123; + skel->data->int_val = skel->data->ushort_val; + + err = skel.load(); + if (err) { + fprintf(stderr, "Skeleton load failed: %d\n", err); + return; + } + + if (!skel->kconfig->CONFIG_BPF_SYSCALL) + fprintf(stderr, "Seems like CONFIG_BPF_SYSCALL isn't set?!\n"); + + err = skel.attach(); + if (err) { + fprintf(stderr, "Skeleton attach failed: %d\n", err); + return; + } + + prog_name = bpf_program__name(skel->progs.handle_sys_enter); + if (prog_name != "handle_sys_enter") + fprintf(stderr, "Unexpected program name: %s\n", prog_name.c_str()); + + bpf_link__destroy(skel->links.handle_sys_enter); + skel->links.handle_sys_enter = bpf_program__attach(skel->progs.handle_sys_enter); + + skel.detach(); + + /* destructor will destory underlying skeleton */ +} + int main(int argc, char *argv[]) { struct btf_dump_opts opts = { }; struct test_core_extern *skel; struct btf *btf; + try_skeleton_template(); + /* libbpf.h */ libbpf_set_print(NULL); @@ -25,7 +107,8 @@ int main(int argc, char *argv[]) /* btf.h */ btf = btf__new(NULL, 0); - btf_dump__new(btf, dump_printf, nullptr, &opts); + if (!libbpf_get_error(btf)) + btf_dump__new(btf, dump_printf, nullptr, &opts); /* BPF skeleton */ skel = test_core_extern__open_and_load(); |