tools/bpf/bpftool/Documentation/bpftool-btf.rst

Source file repositories/reference/linux-study-clean/tools/bpf/bpftool/Documentation/bpftool-btf.rst

File Facts

System
Linux kernel
Corpus path
tools/bpf/bpftool/Documentation/bpftool-btf.rst
Extension
.rst
Size
9278 bytes
Lines
273
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: documentation
Status
atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

struct my_struct {
          const unsigned int const_int_field;
          int bitfield_field: 4;
          char arr_field[16];
          const struct fwd_struct *restrict fwd_field;
          enum my_enum enum_field;
          volatile my_struct_t *typedef_ptr_field;
  };

  union my_union {
          int a;
          struct my_struct b;
  };

  struct my_struct struct_global_var __attribute__((section("data_sec"))) = {
          .bitfield_field = 3,
          .enum_field = VAL1,
  };
  int global_var __attribute__((section("data_sec"))) = 7;

  __attribute__((noinline))
  int my_func(union my_union *arg1, int arg2)
  {
          static int static_var __attribute__((section("data_sec"))) = 123;
          static_var++;
          return static_var;
  }

**$ bpftool btf dump file prog.o**

::

  [1] PTR '(anon)' type_id=2
  [2] UNION 'my_union' size=48 vlen=2
          'a' type_id=3 bits_offset=0
          'b' type_id=4 bits_offset=0
  [3] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED
  [4] STRUCT 'my_struct' size=48 vlen=6
          'const_int_field' type_id=5 bits_offset=0
          'bitfield_field' type_id=3 bits_offset=32 bitfield_size=4
          'arr_field' type_id=8 bits_offset=40
          'fwd_field' type_id=10 bits_offset=192
          'enum_field' type_id=14 bits_offset=256
          'typedef_ptr_field' type_id=15 bits_offset=320
  [5] CONST '(anon)' type_id=6
  [6] INT 'unsigned int' size=4 bits_offset=0 nr_bits=32 encoding=(none)
  [7] INT 'char' size=1 bits_offset=0 nr_bits=8 encoding=SIGNED
  [8] ARRAY '(anon)' type_id=7 index_type_id=9 nr_elems=16
  [9] INT '__ARRAY_SIZE_TYPE__' size=4 bits_offset=0 nr_bits=32 encoding=(none)
  [10] RESTRICT '(anon)' type_id=11
  [11] PTR '(anon)' type_id=12
  [12] CONST '(anon)' type_id=13
  [13] FWD 'fwd_struct' fwd_kind=union
  [14] ENUM 'my_enum' size=4 vlen=2
          'VAL1' val=3
          'VAL2' val=7
  [15] PTR '(anon)' type_id=16
  [16] VOLATILE '(anon)' type_id=17
  [17] TYPEDEF 'my_struct_t' type_id=4
  [18] FUNC_PROTO '(anon)' ret_type_id=3 vlen=2
          'arg1' type_id=1
          'arg2' type_id=3
  [19] FUNC 'my_func' type_id=18
  [20] VAR 'struct_global_var' type_id=4, linkage=global-alloc
  [21] VAR 'global_var' type_id=3, linkage=global-alloc
  [22] VAR 'my_func.static_var' type_id=3, linkage=static
  [23] DATASEC 'data_sec' size=0 vlen=3
          type_id=20 offset=0 size=48
          type_id=21 offset=0 size=4
          type_id=22 offset=52 size=4

Annotation

Implementation Notes