On 2021/7/30 5:35 AM, Andrii Nakryiko wrote: > On Wed, Jul 28, 2021 at 9:55 AM Hengqi Chen <hengqi.chen@xxxxxxxxx> wrote: >> >> Add two new APIs: libbpf_load_vmlinux_btf/libbpf_load_module_btf. >> libbpf_load_vmlinux_btf is just an alias to the existing API named >> libbpf_find_kernel_btf, rename it to be more precisely. >> libbpf_load_module_btf can be used to load module BTF, add it for >> completeness. These two APIs are useful for implementing tracing >> tools and introspection tools. >> This is part of the efforts towards libbpf 1.0. [1] >> >> [1] https://github.com/libbpf/libbpf/issues/280 >> >> Signed-off-by: Hengqi Chen <hengqi.chen@xxxxxxxxx> >> --- >> tools/lib/bpf/btf.c | 15 ++++++++++++++- >> tools/lib/bpf/btf.h | 2 ++ >> tools/lib/bpf/libbpf.c | 4 ++-- >> tools/lib/bpf/libbpf.map | 2 ++ >> 4 files changed, 20 insertions(+), 3 deletions(-) >> >> diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c >> index b46760b93bb4..5f801739a1a2 100644 >> --- a/tools/lib/bpf/btf.c >> +++ b/tools/lib/bpf/btf.c >> @@ -4021,7 +4021,7 @@ static void btf_dedup_merge_hypot_map(struct btf_dedup *d) >> */ >> if (d->hypot_adjust_canon) >> continue; >> - >> + >> if (t_kind == BTF_KIND_FWD && c_kind != BTF_KIND_FWD) >> d->map[t_id] = c_id; >> >> @@ -4395,6 +4395,11 @@ static int btf_dedup_remap_types(struct btf_dedup *d) >> * data out of it to use for target BTF. >> */ >> struct btf *libbpf_find_kernel_btf(void) >> +{ >> + return libbpf_load_vmlinux_btf(); >> +} >> + >> +struct btf *libbpf_load_vmlinux_btf(void) >> { >> struct { >> const char *path_fmt; >> @@ -4440,6 +4445,14 @@ struct btf *libbpf_find_kernel_btf(void) >> return libbpf_err_ptr(-ESRCH); >> } >> >> +struct btf *libbpf_load_module_btf(const char *module_name, struct btf *vmlinux_btf) > > In the light of Quentin's btf__load_from_kernel_by_id(), I'm now > wondering if it's better to keep the naming consistent as > btf__load_vmlinux_btf() and btf__load_module_btf()? And we should put > them after btf__parse() family of constructors, as just another set of > (special, but still) constructors. WDYT? > > Sorry for a bit of back and forth... > > Otherwise everything looks good, thanks. > Thanks for the review. Will update as you suggested. Sometimes naming is the hardest part of programming, I am not good at that. :) (BTW, Quentin's tweet led me to here) >> +{ >> + char path[80]; >> + >> + snprintf(path, sizeof(path), "/sys/kernel/btf/%s", module_name); >> + return btf__parse_split(path, vmlinux_btf); >> +} >> + >> int btf_type_visit_type_ids(struct btf_type *t, type_id_visit_fn visit, void *ctx) >> { >> int i, n, err; >> diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h >> index 374e9f15de2e..1abf94e3bd9e 100644 >> --- a/tools/lib/bpf/btf.h >> +++ b/tools/lib/bpf/btf.h >> @@ -90,6 +90,8 @@ LIBBPF_API __u32 btf_ext__func_info_rec_size(const struct btf_ext *btf_ext); >> LIBBPF_API __u32 btf_ext__line_info_rec_size(const struct btf_ext *btf_ext); >> >> LIBBPF_API struct btf *libbpf_find_kernel_btf(void); >> +LIBBPF_API struct btf *libbpf_load_vmlinux_btf(void); >> +LIBBPF_API struct btf *libbpf_load_module_btf(const char *module_name, struct btf *vmlinux_btf); > > as mentioned above, let's move these right after btf__parse() family, > so that all BTF constructor APIs are listed first. > Sure, will do. >> >> LIBBPF_API int btf__find_str(struct btf *btf, const char *s); >> LIBBPF_API int btf__add_str(struct btf *btf, const char *s); >> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c >> index a1ca6fb0c6d8..321d8f4889af 100644 >> --- a/tools/lib/bpf/libbpf.c >> +++ b/tools/lib/bpf/libbpf.c >> @@ -2680,7 +2680,7 @@ static int bpf_object__load_vmlinux_btf(struct bpf_object *obj, bool force) >> if (!force && !obj_needs_vmlinux_btf(obj)) >> return 0; >> >> - obj->btf_vmlinux = libbpf_find_kernel_btf(); >> + obj->btf_vmlinux = libbpf_load_vmlinux_btf(); >> err = libbpf_get_error(obj->btf_vmlinux); >> if (err) { >> pr_warn("Error loading vmlinux BTF: %d\n", err); >> @@ -8297,7 +8297,7 @@ int libbpf_find_vmlinux_btf_id(const char *name, >> struct btf *btf; >> int err; >> >> - btf = libbpf_find_kernel_btf(); >> + btf = libbpf_load_vmlinux_btf(); >> err = libbpf_get_error(btf); >> if (err) { >> pr_warn("vmlinux BTF is not found\n"); >> diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map >> index c240d488eb5e..2088bdbc0f50 100644 >> --- a/tools/lib/bpf/libbpf.map >> +++ b/tools/lib/bpf/libbpf.map >> @@ -377,4 +377,6 @@ LIBBPF_0.5.0 { >> bpf_object__gen_loader; >> btf_dump__dump_type_data; >> libbpf_set_strict_mode; >> + libbpf_load_vmlinux_btf; >> + libbpf_load_module_btf; >> } LIBBPF_0.4.0; >> -- >> 2.25.1 >>
