btf_struct_access

Name:btf_struct_access

Proto: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)

Type:int

Parameter:

Type	Parameter	Name
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

Return -EINVAL

3745

If btf_member_bitfield_size(t, member) Then Continue

3750

moff = btf_member_bit_offset(t, member) / 8

3751

If off + size <= moff Then Break

3755

If off < moff Then Continue

3759

mtype = btf_type_by_id(btf_vmlinux, type)

3760

mname = __btf_name_by_offset(btf_vmlinux, name_off)

3762

mtype = 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

If IS_ERR(mtype) Then

3765

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

3766

Return -EFAULT

3769

mtrue_end = moff + msize

3770

If off >= mtrue_end Then Continue

3774

If btf_type_is_array(mtype) Then

3818

If moff == mtrue_end Then Continue

3821

msize /= total_nelems

3822

elem_idx = (off - moff) / msize

3823

moff += elem_idx * msize

3824

mtype = elem_type

3830

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

3832

t = mtype

3835

off -= moff

3836

Go to again

3839

If btf_type_is_ptr(mtype) Then

3842

If msize != size || off != moff Then

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

Return -EACCES

3849

stype = btf_type_by_id(btf_vmlinux, type)

3851

When btf_type_is_modifier(stype) cycle

3852

stype = btf_type_by_id(btf_vmlinux, type)

3853

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

3854

next_btf_id = type

3855

Return g points to kernel struct

3865

If off + size > mtrue_end Then

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

Return -EACCES

3872

Return g doesn't contain a valid pointer

Function report