Commit 378714f4 authored by PoroCYon's avatar PoroCYon Committed by PoroCYon
Browse files

make the loader compatible with at least more than one glibc version

parent 9f57498e
......@@ -5,9 +5,13 @@
%define LM_NEXT_OFFSET 0xC
%define LM_ADDR_OFFSET 0
%define LM_INFO_OFFSET 0x20
%define LM_NBUCKETS_OFFSET 0x17c
%define LM_GNU_BUCKETS_OFFSET 0x18c
%define LM_GNU_CHAIN_ZERO_OFFSET 0x190
; by default, use the offset 'correction' from glibc 2.28
%define LM_ENTRY_OFFSET_BASE 340
%define LM_NBUCKETS_OFFSET 0x178
%define LM_GNU_BUCKETS_OFFSET 0x188
%define LM_GNU_CHAIN_ZERO_OFFSET 0x18C
%define DT_VALUE_OFFSET 0x4
%define DYN_PTR_OFFSET 0x4
......@@ -15,6 +19,8 @@
%define DT_SYMTAB 0x6
%define DT_SYMSIZE_SHIFT 4
lm_off_extra:
dd 0
strcmp: ; (const char *s1 (esi), const char *s2 (edi))
push esi
......@@ -53,15 +59,15 @@ link_symbol: ; (struct link_map *entry, uint32_t *h)
; eax = *h % entry->l_nbuckets
mov eax, [ecx]
xor edx, edx
mov ebx, [ebp + LM_NBUCKETS_OFFSET]
mov ebx, [ebp + edi + LM_NBUCKETS_OFFSET]
div ebx
; eax = entry->l_gnu_buckets[eax]
mov eax, [ebp + LM_GNU_BUCKETS_OFFSET]
mov eax, [ebp + edi + LM_GNU_BUCKETS_OFFSET]
mov eax, [eax + edx * 4]
; *h |= 1
or word [ecx], 1
.check_bucket: ; edx = entry->l_gnu_chain_zero[eax] | 1
mov edx, [ebp + LM_GNU_CHAIN_ZERO_OFFSET]
mov edx, [ebp + edi + LM_GNU_CHAIN_ZERO_OFFSET]
mov edx, [edx + eax * 4]
or edx, 1
; check if this is our symbol
......@@ -112,7 +118,10 @@ link: ; (struct link_map *root, char *symtable)
cmp byte [esi], 0
jz .next_library
inc esi
push edi
mov edi, [lm_off_extra]
call link_symbol
pop edi
add esi, 4
jmp .do_symbols
.next_library: pop eax
......@@ -123,6 +132,20 @@ link: ; (struct link_map *root, char *symtable)
extern main
_start:
; try to get the 'version-agnostic' pffset of the stuff we're
; interested in
mov ebx, eax
mov esi, eax
.looper:
lodsd
cmp dword eax, _start
jne short .looper
sub esi, ebx
sub esi, LM_ENTRY_OFFSET_BASE+4 ; +4: take inc-after from lodsb into acct
mov [lm_off_extra], esi
mov eax, ebx
push _symbols
push eax
call link
......
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