libbpf: Auto-detect btf_id of BTF-based raw_tracepoints

[linux.git] / tools / lib / bpf / libbpf.c

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 8d565590ce05962d396fecbacfece893e814fa21..22bf3b1899473c8ac422e9a11139c3e15c5f0092 100644 (file)
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -4489,19 +4489,22 @@ void bpf_program__set_expected_attach_type(struct bpf_program *prog,
        prog->expected_attach_type = type;
 }
 
-#define BPF_PROG_SEC_IMPL(string, ptype, eatype, is_attachable, atype) \
-       { string, sizeof(string) - 1, ptype, eatype, is_attachable, atype }
+#define BPF_PROG_SEC_IMPL(string, ptype, eatype, is_attachable, btf, atype) \
+       { string, sizeof(string) - 1, ptype, eatype, is_attachable, btf, atype }
 
 /* Programs that can NOT be attached. */
-#define BPF_PROG_SEC(string, ptype) BPF_PROG_SEC_IMPL(string, ptype, 0, 0, 0)
+#define BPF_PROG_SEC(string, ptype) BPF_PROG_SEC_IMPL(string, ptype, 0, 0, 0, 0)
 
 /* Programs that can be attached. */
 #define BPF_APROG_SEC(string, ptype, atype) \
-       BPF_PROG_SEC_IMPL(string, ptype, 0, 1, atype)
+       BPF_PROG_SEC_IMPL(string, ptype, 0, 1, 0, atype)
 
 /* Programs that must specify expected attach type at load time. */
 #define BPF_EAPROG_SEC(string, ptype, eatype) \
-       BPF_PROG_SEC_IMPL(string, ptype, eatype, 1, eatype)
+       BPF_PROG_SEC_IMPL(string, ptype, eatype, 1, 0, eatype)
+
+/* Programs that use BTF to identify attach point */
+#define BPF_PROG_BTF(string, ptype) BPF_PROG_SEC_IMPL(string, ptype, 0, 0, 1, 0)
 
 /* Programs that can be attached but attach type can't be identified by section
  * name. Kept for backward compatibility.
@@ -4513,7 +4516,8 @@ static const struct {
        size_t len;
        enum bpf_prog_type prog_type;
        enum bpf_attach_type expected_attach_type;
-       int is_attachable;
+       bool is_attachable;
+       bool is_attach_btf;
        enum bpf_attach_type attach_type;
 } section_names[] = {
        BPF_PROG_SEC("socket",                  BPF_PROG_TYPE_SOCKET_FILTER),
@@ -4523,6 +4527,7 @@ static const struct {
        BPF_PROG_SEC("action",                  BPF_PROG_TYPE_SCHED_ACT),
        BPF_PROG_SEC("tracepoint/",             BPF_PROG_TYPE_TRACEPOINT),
        BPF_PROG_SEC("raw_tracepoint/",         BPF_PROG_TYPE_RAW_TRACEPOINT),
+       BPF_PROG_BTF("tp_btf/",                 BPF_PROG_TYPE_RAW_TRACEPOINT),
        BPF_PROG_SEC("xdp",                     BPF_PROG_TYPE_XDP),
        BPF_PROG_SEC("perf_event",              BPF_PROG_TYPE_PERF_EVENT),
        BPF_PROG_SEC("lwt_in",                  BPF_PROG_TYPE_LWT_IN),
@@ -4627,6 +4632,27 @@ int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
                        continue;
                *prog_type = section_names[i].prog_type;
                *expected_attach_type = section_names[i].expected_attach_type;
+               if (section_names[i].is_attach_btf) {
+                       struct btf *btf = bpf_core_find_kernel_btf();
+                       char raw_tp_btf_name[128] = "btf_trace_";
+                       char *dst = raw_tp_btf_name + sizeof("btf_trace_") - 1;
+                       int ret;
+
+                       if (IS_ERR(btf)) {
+                               pr_warning("vmlinux BTF is not found\n");
+                               return -EINVAL;
+                       }
+                       /* prepend "btf_trace_" prefix per kernel convention */
+                       strncat(dst, name + section_names[i].len,
+                               sizeof(raw_tp_btf_name) - (dst - raw_tp_btf_name));
+                       ret = btf__find_by_name(btf, raw_tp_btf_name);
+                       btf__free(btf);
+                       if (ret <= 0) {
+                               pr_warning("%s is not found in vmlinux BTF\n", dst);
+                               return -EINVAL;
+                       }
+                       *expected_attach_type = ret;
+               }
                return 0;
        }
        pr_warning("failed to guess program type based on ELF section name '%s'\n", name);