@@ -1318,35 +1318,27 @@ const char *btf__name_by_offset(const struct btf *btf, __u32 offset)
return btf__str_by_offset(btf, offset);
}
-int btf__get_from_id(__u32 id, struct btf **btf)
+struct btf *btf_get_from_fd(int btf_fd, struct btf *base_btf)
{
- struct bpf_btf_info btf_info = { 0 };
+ struct bpf_btf_info btf_info;
__u32 len = sizeof(btf_info);
__u32 last_size;
- int btf_fd;
+ struct btf *btf;
void *ptr;
int err;
- err = 0;
- *btf = NULL;
- btf_fd = bpf_btf_get_fd_by_id(id);
- if (btf_fd < 0)
- return 0;
-
/* we won't know btf_size until we call bpf_obj_get_info_by_fd(). so
* let's start with a sane default - 4KiB here - and resize it only if
* bpf_obj_get_info_by_fd() needs a bigger buffer.
*/
- btf_info.btf_size = 4096;
- last_size = btf_info.btf_size;
+ last_size = 4096;
ptr = malloc(last_size);
- if (!ptr) {
- err = -ENOMEM;
- goto exit_free;
- }
+ if (!ptr)
+ return ERR_PTR(-ENOMEM);
- memset(ptr, 0, last_size);
+ memset(&btf_info, 0, sizeof(btf_info));
btf_info.btf = ptr_to_u64(ptr);
+ btf_info.btf_size = last_size;
err = bpf_obj_get_info_by_fd(btf_fd, &btf_info, &len);
if (!err && btf_info.btf_size > last_size) {
@@ -1355,31 +1347,48 @@ int btf__get_from_id(__u32 id, struct btf **btf)
last_size = btf_info.btf_size;
temp_ptr = realloc(ptr, last_size);
if (!temp_ptr) {
- err = -ENOMEM;
+ btf = ERR_PTR(-ENOMEM);
goto exit_free;
}
ptr = temp_ptr;
- memset(ptr, 0, last_size);
+
+ len = sizeof(btf_info);
+ memset(&btf_info, 0, sizeof(btf_info));
btf_info.btf = ptr_to_u64(ptr);
+ btf_info.btf_size = last_size;
+
err = bpf_obj_get_info_by_fd(btf_fd, &btf_info, &len);
}
if (err || btf_info.btf_size > last_size) {
- err = errno;
+ btf = err ? ERR_PTR(-errno) : ERR_PTR(-E2BIG);
goto exit_free;
}
- *btf = btf__new((__u8 *)(long)btf_info.btf, btf_info.btf_size);
- if (IS_ERR(*btf)) {
- err = PTR_ERR(*btf);
- *btf = NULL;
- }
+ btf = btf_new(ptr, btf_info.btf_size, base_btf);
exit_free:
- close(btf_fd);
free(ptr);
+ return btf;
+}
- return err;
+int btf__get_from_id(__u32 id, struct btf **btf)
+{
+ struct btf *res;
+ int btf_fd;
+
+ *btf = NULL;
+ btf_fd = bpf_btf_get_fd_by_id(id);
+ if (btf_fd < 0)
+ return -errno;
+
+ res = btf_get_from_fd(btf_fd, NULL);
+ close(btf_fd);
+ if (IS_ERR(res))
+ return PTR_ERR(res);
+
+ *btf = res;
+ return 0;
}
int btf__get_map_kv_tids(const struct btf *btf, const char *map_name,
@@ -155,6 +155,7 @@ int bpf_object__section_size(const struct bpf_object *obj, const char *name,
__u32 *size);
int bpf_object__variable_offset(const struct bpf_object *obj, const char *name,
__u32 *off);
+struct btf *btf_get_from_fd(int btf_fd, struct btf *base_btf);
struct btf_ext_info {
/*
Add a btf_get_from_fd() helper, which constructs struct btf from in-kernel BTF data by FD. This is used for loading module BTFs. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> --- tools/lib/bpf/btf.c | 61 +++++++++++++++++++-------------- tools/lib/bpf/libbpf_internal.h | 1 + 2 files changed, 36 insertions(+), 26 deletions(-)