2929#ifndef max
3030# define max (x , y ) ((x) < (y) ? (y) : (x))
3131#endif
32+ #ifndef offsetofend
33+ # define offsetofend (TYPE , FIELD ) \
34+ (offsetof(TYPE, FIELD) + sizeof(((TYPE *)0)->FIELD))
35+ #endif
3236
3337extern void libbpf_print (enum libbpf_print_level level ,
3438 const char * format , ...)
@@ -46,4 +50,105 @@ do { \
4650int libbpf__load_raw_btf (const char * raw_types , size_t types_len ,
4751 const char * str_sec , size_t str_len );
4852
53+ struct btf_ext_info {
54+ /*
55+ * info points to the individual info section (e.g. func_info and
56+ * line_info) from the .BTF.ext. It does not include the __u32 rec_size.
57+ */
58+ void * info ;
59+ __u32 rec_size ;
60+ __u32 len ;
61+ };
62+
63+ #define for_each_btf_ext_sec (seg , sec ) \
64+ for (sec = (seg)->info; \
65+ (void *)sec < (seg)->info + (seg)->len; \
66+ sec = (void *)sec + sizeof(struct btf_ext_info_sec) + \
67+ (seg)->rec_size * sec->num_info)
68+
69+ #define for_each_btf_ext_rec (seg , sec , i , rec ) \
70+ for (i = 0, rec = (void *)&(sec)->data; \
71+ i < (sec)->num_info; \
72+ i++, rec = (void *)rec + (seg)->rec_size)
73+
74+ struct btf_ext {
75+ union {
76+ struct btf_ext_header * hdr ;
77+ void * data ;
78+ };
79+ struct btf_ext_info func_info ;
80+ struct btf_ext_info line_info ;
81+ struct btf_ext_info offset_reloc_info ;
82+ __u32 data_size ;
83+ };
84+
85+ struct btf_ext_info_sec {
86+ __u32 sec_name_off ;
87+ __u32 num_info ;
88+ /* Followed by num_info * record_size number of bytes */
89+ __u8 data [0 ];
90+ };
91+
92+ /* The minimum bpf_func_info checked by the loader */
93+ struct bpf_func_info_min {
94+ __u32 insn_off ;
95+ __u32 type_id ;
96+ };
97+
98+ /* The minimum bpf_line_info checked by the loader */
99+ struct bpf_line_info_min {
100+ __u32 insn_off ;
101+ __u32 file_name_off ;
102+ __u32 line_off ;
103+ __u32 line_col ;
104+ };
105+
106+ /* The minimum bpf_offset_reloc checked by the loader
107+ *
108+ * Offset relocation captures the following data:
109+ * - insn_off - instruction offset (in bytes) within a BPF program that needs
110+ * its insn->imm field to be relocated with actual offset;
111+ * - type_id - BTF type ID of the "root" (containing) entity of a relocatable
112+ * offset;
113+ * - access_str_off - offset into corresponding .BTF string section. String
114+ * itself encodes an accessed field using a sequence of field and array
115+ * indicies, separated by colon (:). It's conceptually very close to LLVM's
116+ * getelementptr ([0]) instruction's arguments for identifying offset to
117+ * a field.
118+ *
119+ * Example to provide a better feel.
120+ *
121+ * struct sample {
122+ * int a;
123+ * struct {
124+ * int b[10];
125+ * };
126+ * };
127+ *
128+ * struct sample *s = ...;
129+ * int x = &s->a; // encoded as "0:0" (a is field #0)
130+ * int y = &s->b[5]; // encoded as "0:1:0:5" (anon struct is field #1,
131+ * // b is field #0 inside anon struct, accessing elem #5)
132+ * int z = &s[10]->b; // encoded as "10:1" (ptr is used as an array)
133+ *
134+ * type_id for all relocs in this example will capture BTF type id of
135+ * `struct sample`.
136+ *
137+ * Such relocation is emitted when using __builtin_preserve_access_index()
138+ * Clang built-in, passing expression that captures field address, e.g.:
139+ *
140+ * bpf_probe_read(&dst, sizeof(dst),
141+ * __builtin_preserve_access_index(&src->a.b.c));
142+ *
143+ * In this case Clang will emit offset relocation recording necessary data to
144+ * be able to find offset of embedded `a.b.c` field within `src` struct.
145+ *
146+ * [0] https://llvm.org/docs/LangRef.html#getelementptr-instruction
147+ */
148+ struct bpf_offset_reloc {
149+ __u32 insn_off ;
150+ __u32 type_id ;
151+ __u32 access_str_off ;
152+ };
153+
49154#endif /* __LIBBPF_LIBBPF_INTERNAL_H */
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