korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-11-16 00:34:20 +08:00
Code Issues Packages Projects Releases Wiki Activity

libbpf: Add generic BTF type shallow copy API

Browse Source 
Add btf__add_type() API that performs shallow copy of a given BTF type from
the source BTF into the destination BTF. All the information and type IDs are
preserved, but all the strings encountered are added into the destination BTF
and corresponding offsets are rewritten. BTF type IDs are assumed to be
correct or such that will be (somehow) modified afterwards.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210318194036.3521577-6-andrii@kernel.org
This commit is contained in:
Andrii Nakryiko 2021-03-18 12:40:29 -07:00 committed by Alexei Starovoitov
parent 90d76d3ece
commit 9af44bc5d4
3 changed files with 51 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

48
tools/lib/bpf/btf.c
View File

@ -1629,6 +1629,54 @@ static int btf_commit_type(struct btf *btf, int data_sz)
return btf->start_id + btf->nr_types - 1;
}
struct btf_pipe {
const struct btf *src;
struct btf *dst;
};
static int btf_rewrite_str(__u32 *str_off, void *ctx)
{
struct btf_pipe *p = ctx;
int off;
if (!*str_off) /* nothing to do for empty strings */
return 0;
off = btf__add_str(p->dst, btf__str_by_offset(p->src, *str_off));
if (off < 0)
return off;
*str_off = off;
return 0;
}
int btf__add_type(struct btf *btf, const struct btf *src_btf, const struct btf_type *src_type)
{
struct btf_pipe p = { .src = src_btf, .dst = btf };
struct btf_type *t;
int sz, err;
sz = btf_type_size(src_type);
if (sz < 0)
return sz;
/* deconstruct BTF, if necessary, and invalidate raw_data */
if (btf_ensure_modifiable(btf))
return -ENOMEM;
t = btf_add_type_mem(btf, sz);
if (!t)
return -ENOMEM;
memcpy(t, src_type, sz);
err = btf_type_visit_str_offs(t, btf_rewrite_str, &p);
if (err)
return err;
return btf_commit_type(btf, sz);
}
/*
* Append new BTF_KIND_INT type with:
* - *name* - non-empty, non-NULL type name;

2
tools/lib/bpf/btf.h
View File

@ -93,6 +93,8 @@ LIBBPF_API struct btf *libbpf_find_kernel_btf(void);
LIBBPF_API int btf__find_str(struct btf *btf, const char *s);
LIBBPF_API int btf__add_str(struct btf *btf, const char *s);
LIBBPF_API int btf__add_type(struct btf *btf, const struct btf *src_btf,
const struct btf_type *src_type);
LIBBPF_API int btf__add_int(struct btf *btf, const char *name, size_t byte_sz, int encoding);
LIBBPF_API int btf__add_float(struct btf *btf, const char *name, size_t byte_sz);

1
tools/lib/bpf/libbpf.map
View File

@ -354,4 +354,5 @@ LIBBPF_0.3.0 {
LIBBPF_0.4.0 {
global:
btf__add_float;
btf__add_type;
} LIBBPF_0.3.0;