tools: libbpf: expose the prog type guessing from section name logic

libbpf can guess program type based on ELF section names.  As libbpf
becomes more popular its association between section name strings and
types becomes more of a standard.  Allow libbpf users to use the same
logic for matching strings to types, e.g. when the string originates
from command line.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 38ed3e92e39305a1bbf5ad0c1a34ac62eaf49395..42f31eff5f3ff3ae95c83641235cf65da1ee67f5 100644 (file)
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -2081,23 +2081,31 @@ static const struct {
 #undef BPF_S_PROG_SEC
 #undef BPF_SA_PROG_SEC
 
-static int bpf_program__identify_section(struct bpf_program *prog)
+int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
+                            enum bpf_attach_type *expected_attach_type)
 {
        int i;
 
-       if (!prog->section_name)
-               goto err;
-
-       for (i = 0; i < ARRAY_SIZE(section_names); i++)
-               if (strncmp(prog->section_name, section_names[i].sec,
-                           section_names[i].len) == 0)
-                       return i;
+       if (!name)
+               return -EINVAL;
 
-err:
-       pr_warning("failed to guess program type based on section name %s\n",
-                  prog->section_name);
+       for (i = 0; i < ARRAY_SIZE(section_names); i++) {
+               if (strncmp(name, section_names[i].sec, section_names[i].len))
+                       continue;
+               *prog_type = section_names[i].prog_type;
+               *expected_attach_type = section_names[i].expected_attach_type;
+               return 0;
+       }
+       return -EINVAL;
+}
 
-       return -1;
+static int
+bpf_program__identify_section(struct bpf_program *prog,
+                             enum bpf_prog_type *prog_type,
+                             enum bpf_attach_type *expected_attach_type)
+{
+       return libbpf_prog_type_by_name(prog->section_name, prog_type,
+                                       expected_attach_type);
 }
 
 int bpf_map__fd(struct bpf_map *map)
@@ -2230,7 +2238,6 @@ int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr,
        enum bpf_prog_type prog_type;
        struct bpf_object *obj;
        struct bpf_map *map;
-       int section_idx;
        int err;
 
        if (!attr)
@@ -2252,14 +2259,14 @@ int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr,
                prog->prog_ifindex = attr->ifindex;
                expected_attach_type = attr->expected_attach_type;
                if (prog_type == BPF_PROG_TYPE_UNSPEC) {
-                       section_idx = bpf_program__identify_section(prog);
-                       if (section_idx < 0) {
+                       err = bpf_program__identify_section(prog, &prog_type,
+                                                           &expected_attach_type);
+                       if (err < 0) {
+                               pr_warning("failed to guess program type based on section name %s\n",
+                                          prog->section_name);
                                bpf_object__close(obj);
                                return -EINVAL;
                        }
-                       prog_type = section_names[section_idx].prog_type;
-                       expected_attach_type =
-                               section_names[section_idx].expected_attach_type;
                }
 
                bpf_program__set_type(prog, prog_type);

diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 564f4be9bae061743bd4ec8d9315a45d55156bb6..d1ce5c828e2edb82e3b75ed25812e1fa259ea47c 100644 (file)
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -92,6 +92,9 @@ int bpf_object__set_priv(struct bpf_object *obj, void *priv,
                         bpf_object_clear_priv_t clear_priv);
 void *bpf_object__priv(struct bpf_object *prog);
 
+int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
+                            enum bpf_attach_type *expected_attach_type);
+
 /* Accessors of bpf_program */
 struct bpf_program;
 struct bpf_program *bpf_program__next(struct bpf_program *prog,