btf_struct_access

函数名称：btf_struct_access

函数原型：int btf_struct_access(struct bpf_verifier_log *log, const struct btf_type *t, int off, int size, enum bpf_access_type atype, u32 *next_btf_id)

返回类型：int

参数：

类型	参数	名称
struct bpf_verifier_log *	log
const struct btf_type *	t
int	off
int	size
enum bpf_access_type	atype
u32 *	next_btf_id

3740

bpf_log(log, "Type '%s' is not a struct", tname)

3741

返回:负EINVAL

3745

如果btf_member_bitfield_size(t, member)则继续下一循环

3750

moff等于btf_member_bit_offset(t, member)除8

3751

如果off加size小于等于moff则退出

3755

如果off小于moff则继续下一循环

3759

mtype等于btf_type_by_id(btf_vmlinux, type)

3760

mname等于__btf_name_by_offset(btf_vmlinux, name_off)

3762

mtype等于Resolve the size of a passed-in "type"* return type: type "u32[x][y]", i.e. BTF_KIND_ARRAY,* *type_size: (x * y * sizeof(u32)). Hence, *type_size always* corresponds to the return type.* *elem_type: u32* *total_nelems: (x * y)

3764

如果是错误则

3765

bpf_log(log, "field %s doesn't have size\n", mname)

3766

返回:负EFAULT

3769

mtrue_end等于moff加msize

3770

如果off大于等于mtrue_end则继续下一循环

3774

如果btf_type_is_array(mtype)则

3818

如果moff恒等于mtrue_end则继续下一循环

3821

msize除等于total_nelems

3822

elem_idx等于off减moff的差除msize

3823

moff加等于elem_idx乘msize

3824

mtype等于elem_type

3830

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

3832

t等于mtype

3835

off减等于moff

3836

转到:again

3839

如果btf_type_is_ptr(mtype)则

3842

如果msize不等于size或off不等于moff则

3843

bpf_log(log, "cannot access ptr member %s with moff %u in struct %s with off %u size %u\n", mname, moff, tname, off, size)

3846

返回:负EACCES

3849

stype等于btf_type_by_id(btf_vmlinux, type)

3851

当btf_type_is_modifier(stype)循环

3852

stype等于btf_type_by_id(btf_vmlinux, type)

3853

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

3854

next_btf_id等于type

3855

返回:g points to kernel struct

3865

如果off加size大于mtrue_end则

3866

bpf_log(log, "access beyond the end of member %s (mend:%u) in struct %s with off %u size %u\n", mname, mtrue_end, tname, off, size)

3869

返回:负EACCES

3872

返回:g doesn't contain a valid pointer

函数逻辑报告