btf_ctx_access

函数名称：btf_ctx_access

函数原型：bool btf_ctx_access(int off, int size, enum bpf_access_type type, const struct bpf_prog *prog, struct bpf_insn_access_aux *info)

返回类型：bool

参数：

类型	参数	名称
int	off
int	size
enum bpf_access_type	type
const struct bpf_prog *	prog
struct bpf_insn_access_aux *	info

3636

t等于 BTF_KIND_FUNC_PROTO for valid attach_btf_id

3637

tgt_prog等于linked_prog

3638

btf等于bpf_prog_get_target_btf(prog)

3639

tname等于 function name for valid attach_btf_id

3640

log等于r verbose logs

3645

如果off取模8则

3646

bpf_log(log, "func '%s' offset %d is not multiple of 8\n", tname, off)

3648

返回:false

3650

arg等于off除8

3651

args等于t加1

3653

nr_args等于如果t则btf_type_vlen(t)否则5

3654

如果 true if attaching to BTF-enabled raw tp 则

3656

args自加

3657

nr_args自减

3660

如果 For some prog types 恒等于BPF_TRACE_FEXIT且arg恒等于nr_args则

3662

如果非t则返回:true

3666

t等于btf_type_by_id(btf, type)

3667

否则如果arg大于等于nr_args则

3668

bpf_log(log, "func '%s' doesn't have %d-th argument\n", tname, arg + 1)

3670

返回:false

3671

否则

3672

如果非t则返回:true

3675

t等于btf_type_by_id(btf, type)

3678

当btf_type_is_modifier(t)循环

3679

t等于btf_type_by_id(btf, type)

3680

如果btf_type_is_int(t)则返回:true

3683

如果非btf_type_is_ptr(t)则

3684

bpf_log(log, "func '%s' arg%d '%s' has type %s. Only pointer access is allowed\n", tname, arg, __btf_name_by_offset(btf, name_off), btf_kind_str[BTF_INFO_KIND( "info" bits arrangement * bits 0-15: vlen (e.g. # of struct's members) * bits 16-23: unused * bits 24-27: kind (e.g. int, ptr, array...etc) * bits 28-30: unused * bit 31: kind_flag, currently used by * struct, union and fwd)])

3689

返回:false

3691

如果type恒等于0则返回:true

3699

reg_type等于g points to kernel struct

3700

btf_id等于type

3702

如果tgt_prog则

3703

ret等于btf_translate_to_vmlinux(log, btf, t, Type of BPF program )

3704

如果ret大于0则

3705

btf_id等于ret

3706

返回:true

3707

否则

3708

返回:false

3711

t等于btf_type_by_id(btf, type)

3713

当btf_type_is_modifier(t)循环

3714

t等于btf_type_by_id(btf, type)

3715

如果非 is only a special case of struct:* all its offsetof(member) == 0则

3716

bpf_log(log, "func '%s' arg%d type %s is not a struct\n", tname, arg, btf_kind_str[BTF_INFO_KIND( "info" bits arrangement * bits 0-15: vlen (e.g. # of struct's members) * bits 16-23: unused * bits 24-27: kind (e.g. int, ptr, array...etc) * bits 28-30: unused * bit 31: kind_flag, currently used by * struct, union and fwd)])

3719

返回:false

3721

bpf_log(log, "func '%s' arg%d has btf_id %d type %s '%s'\n", tname, arg, btf_id, btf_kind_str[BTF_INFO_KIND( "info" bits arrangement * bits 0-15: vlen (e.g. # of struct's members) * bits 16-23: unused * bits 24-27: kind (e.g. int, ptr, array...etc) * bits 28-30: unused * bit 31: kind_flag, currently used by * struct, union and fwd)], __btf_name_by_offset(btf, name_off))

3724

返回:true

**调用者**
名称	描述
tracing_prog_is_valid_access

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