[PATCH bpf-next v3 3/6] resolve_btfids: Introduce enum btf_id_kind

Ihor Solodrai
2025-12-05T22:31:56Z

Instead of using multiple flags, make struct btf_id tagged with an
enum value indicating its kind in the context of resolve_btfids.

Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
---
tools/bpf/resolve_btfids/main.c | 76 ++++++++++++++++++++++-----------
1 file changed, 52 insertions(+), 24 deletions(-)

diff --git a/tools/bpf/resolve_btfids/main.c b/tools/bpf/resolve_btfids/main.c
index b4caae1170dd..cb1e69eb0bd7 100644
--- a/tools/bpf/resolve_btfids/main.c
+++ b/tools/bpf/resolve_btfids/main.c
@@ -98,6 +98,13 @@
# error "Unknown machine endianness!"
#endif

+enum btf_id_kind {
+ BTF_ID_KIND_NONE,
+ BTF_ID_KIND_SYM,
+ BTF_ID_KIND_SET,
+ BTF_ID_KIND_SET8
+};
+
struct btf_id {
struct rb_node rb_node;
char *name;
@@ -105,9 +112,8 @@ struct btf_id {
int id;
int cnt;
};
+ enum btf_id_kind kind;
int addr_cnt;
- bool is_set;
- bool is_set8;
Elf64_Addr addr[ADDR_CNT];
};

@@ -197,8 +203,7 @@ static struct btf_id *btf_id__find(struct rb_root *root, const char *name)
return NULL;
}

-static struct btf_id *
-btf_id__add(struct rb_root *root, char *name, bool unique)
+static struct btf_id *btf_id__add(struct rb_root *root, char *name, enum btf_id_kind kind)
{
struct rb_node **p = &root->rb_node;
struct rb_node *parent = NULL;
@@ -213,14 +218,19 @@ btf_id__add(struct rb_root *root, char *name, bool unique)
p = &(*p)->rb_left;
else if (cmp > 0)
p = &(*p)->rb_right;
- else
- return unique ? NULL : id;
+ else if (kind == BTF_ID_KIND_SYM && id->kind == BTF_ID_KIND_SYM)
+ return id;
+ else {
+ pr_err("Unexpected duplicate symbol %s of kind %d\n", name, id->kind);
+ return NULL;
+ }
}

id = zalloc(sizeof(*id));
if (id) {
pr_debug("adding symbol %s\n", name);
id->name = name;
+ id->kind = kind;
rb_link_node(&id->rb_node, parent, p);
rb_insert_color(&id->rb_node, root);
}
@@ -260,22 +270,36 @@ static char *get_id(const char *prefix_end)
return id;
}

-static struct btf_id *add_set(struct object *obj, char *name, bool is_set8)
+static struct btf_id *add_set(struct object *obj, char *name, enum btf_id_kind kind)
{
+ int len = strlen(name);
+ int prefixlen;
+ char *id;
+
/*
* __BTF_ID__set__name
* name = ^
* id = ^
*/
- char *id = name + (is_set8 ? sizeof(BTF_SET8 "__") : sizeof(BTF_SET "__")) - 1;
- int len = strlen(name);
+ switch (kind) {
+ case BTF_ID_KIND_SET:
+ prefixlen = sizeof(BTF_SET "__") - 1;
+ break;
+ case BTF_ID_KIND_SET8:
+ prefixlen = sizeof(BTF_SET8 "__") - 1;
+ break;
+ default:
+ pr_err("Unexpected kind %d passed to %s() for symbol %s\n", kind, __func__, name);
+ return NULL;
+ }

+ id = name + prefixlen - 1;
if (id >= name + len) {
pr_err("FAILED to parse set name: %s\n", name);
return NULL;
}

- return btf_id__add(&obj->sets, id, true);
+ return btf_id__add(&obj->sets, id, kind);
}

static struct btf_id *add_symbol(struct rb_root *root, char *name, size_t size)
@@ -288,7 +312,7 @@ static struct btf_id *add_symbol(struct rb_root *root, char *name, size_t size)
return NULL;
}

- return btf_id__add(root, id, false);
+ return btf_id__add(root, id, BTF_ID_KIND_SYM);
}

/* Older libelf.h and glibc elf.h might not yet define the ELF compression types. */
@@ -491,28 +515,24 @@ static int symbols_collect(struct object *obj)
id = add_symbol(&obj->funcs, prefix, sizeof(BTF_FUNC) - 1);
/* set8 */
} else if (!strncmp(prefix, BTF_SET8, sizeof(BTF_SET8) - 1)) {
- id = add_set(obj, prefix, true);
+ id = add_set(obj, prefix, BTF_ID_KIND_SET8);
/*
* SET8 objects store list's count, which is encoded
* in symbol's size, together with 'cnt' field hence
* that - 1.
*/
- if (id) {
+ if (id)
id->cnt = sym.st_size / sizeof(uint64_t) - 1;
- id->is_set8 = true;
- }
/* set */
} else if (!strncmp(prefix, BTF_SET, sizeof(BTF_SET) - 1)) {
- id = add_set(obj, prefix, false);
+ id = add_set(obj, prefix, BTF_ID_KIND_SET);
/*
* SET objects store list's count, which is encoded
* in symbol's size, together with 'cnt' field hence
* that - 1.
*/
- if (id) {
+ if (id)
id->cnt = sym.st_size / sizeof(int) - 1;
- id->is_set = true;
- }
} else {
pr_err("FAILED unsupported prefix %s\n", prefix);
return -1;
@@ -643,7 +663,7 @@ static int id_patch(struct object *obj, struct btf_id *id)
int i;

/* For set, set8, id->id may be 0 */
- if (!id->id && !id->is_set && !id->is_set8) {
+ if (!id->id && id->kind != BTF_ID_KIND_SET && id->kind != BTF_ID_KIND_SET8) {
pr_err("WARN: resolve_btfids: unresolved symbol %s\n", id->name);
warnings++;
}
@@ -696,6 +716,7 @@ static int sets_patch(struct object *obj)
{
Elf_Data *data = obj->efile.idlist;
struct rb_node *next;
+ int cnt;

next = rb_first(&obj->sets);
while (next) {
@@ -715,11 +736,15 @@ static int sets_patch(struct object *obj)
return -1;
}

- if (id->is_set) {
+ switch (id->kind) {
+ case BTF_ID_KIND_SET:
set = data->d_buf + off;
+ cnt = set->cnt;
qsort(set->ids, set->cnt, sizeof(set->ids[0]), cmp_id);
- } else {
+ break;
+ case BTF_ID_KIND_SET8:
set8 = data->d_buf + off;
+ cnt = set8->cnt;
/*
* Make sure id is at the beginning of the pairs
* struct, otherwise the below qsort would not work.
@@ -744,10 +769,13 @@ static int sets_patch(struct object *obj)
bswap_32(set8->pairs[i].flags);
}
}
+ break;
+ default:
+ pr_err("Unexpected btf_id_kind %d for set '%s'\n", id->kind, id->name);
+ return -1;
}

- pr_debug("sorting addr %5lu: cnt %6d [%s]\n",
- off, id->is_set ? set->cnt : set8->cnt, id->name);
+ pr_debug("sorting addr %5lu: cnt %6d [%s]\n", off, cnt, id->name);

next = rb_next(next);
}
--
2.52.0