/**
* Remove annotation classes that are marked explicitly with a removable
* annotation (specified as "kill_annos" in config). Facebook uses these to
* remove DI binding annotations.
*/
void kill_annotation_classes(
Scope& scope,
const std::unordered_set<DexType*>& kill_annos
) {
// Determine which annotation classes are removable.
class_set_t bannotations;
for (auto clazz : scope) {
if (!(clazz->get_access() & DexAccessFlags::ACC_ANNOTATION)) continue;
auto aset = clazz->get_anno_set();
if (aset == nullptr) continue;
auto& annos = aset->get_annotations();
for (auto anno : annos) {
if (kill_annos.count(anno->type())) {
bannotations.insert(clazz);
TRACE(CLASSKILL, 5, "removable annotation class %s\n",
SHOW(clazz->get_type()));
}
}
}
// Annotation classes referenced explicitly can't be removed.
walk_code(
scope,
[](DexMethod*) { return true; },
[&](DexMethod* meth, DexCode* code) {
auto opcodes = code->get_instructions();
for (const auto& opcode : opcodes) {
if (opcode->has_types()) {
auto typeop = static_cast<DexOpcodeType*>(opcode);
auto dtexclude = typeop->get_type();
DexClass* exclude = type_class(dtexclude);
if (exclude != nullptr && bannotations.count(exclude)) {
bannotations.erase(exclude);
}
}
}
});
// Do the removal.
int annotations_removed_count = 0;
if (bannotations.size()) {
// We have some annotations we can kill. First let's clear all annotation
// references to the classes.
annotations_removed_count =
clear_annotation_references(scope, bannotations);
scope.erase(
std::remove_if(
scope.begin(), scope.end(),
[&](DexClass* cls) { return bannotations.count(cls); }),
scope.end());
}
TRACE(CLASSKILL, 1,
"Annotation classes removed %lu\n",
bannotations.size());
TRACE(CLASSKILL, 1,
"Method param annotations removed %d\n",
annotations_removed_count);
}
TITANIUM_PROPERTY_GETTER(View, annotations)
{
std::vector<JSValue> js_annotations;
const auto annotations = get_annotations();
for (auto annotation : annotations) {
js_annotations.push_back(annotation->get_object());
}
return get_context().CreateArray(js_annotations);
}
bool is_kept_by_annotation(const DexField* sfield,
const std::unordered_set<DexType*>& keep_annos) {
auto annoset = sfield->get_anno_set();
if (!annoset) {
return false;
}
auto const& annos = annoset->get_annotations();
for (auto& anno : annos) {
if (keep_annos.count(anno->type())) {
return true;
}
}
return false;
}
Annotation *get_annotation_at(const char *name) {
return get_annotations()->get_at(name).get();
}
int main(int argc, char **argv)
{
FILE *exe;
FILE *patch;
unsigned int exe_length;
unsigned int patch_length;
char *exe_data;
char *patch_data;
char label[256];
unsigned int address = 0;
unsigned int a;
char *l;
int i;
char *map_buf;
FILE *fh;
char *source;
char *nasm = "nasm";
char nasm_flags[1024] = { '\0' };
char *tmp_name;
char *out_name;
char *inc_name;
char *exe_name;
char buf[1024];
memset(&annotations, 0, sizeof annotations);
if (argc < 3)
{
fprintf(stderr, "linker for ra303p git~%s (c) 2012 Toni Spets\n\n", REV);
fprintf(stderr, "usage: %s <source file> <out include file> <target executable> [nasm [nasm flags]]\n", argv[0]);
return 1;
}
inc_name = argv[2];
exe_name = argv[3];
tmp_name = tempnam(NULL, "lnkr-");
out_name = tempnam(NULL, "lnkr-");
if (argc > 3)
{
nasm = argv[4];
}
if (argc > 4)
{
int i = 5;
for (; i < argc; i++)
{
strncat(nasm_flags, " ", sizeof nasm_flags);
strncat(nasm_flags, argv[i], sizeof nasm_flags);
}
}
snprintf(buf, 1024, "%s%s -e %s", nasm, nasm_flags, argv[1]);
if ((fh = popen(buf, "r")) == NULL)
{
fprintf(stderr, "%s\n", buf);
perror(nasm);
return 1;
}
source = read_stream(fh);
if (pclose(fh) != 0)
{
return 1;
}
get_annotations(source);
if ((fh = fopen(tmp_name, "w")) == NULL)
{
perror(tmp_name);
return 1;
}
/* always working with 32 bit images and need to map all for linking */
fprintf(fh, "[bits 32]\n[map all]\n");
fwrite(source, strlen(source), 1, fh);
fclose(fh);
snprintf(buf, 1024, "%s%s -f bin %s -o %s", nasm, nasm_flags, tmp_name, out_name);
if ((fh = popen(buf, "r")) == NULL)
{
fprintf(stderr, "%s\n", buf);
perror(nasm);
unlink(tmp_name);
return 1;
}
map_buf = read_stream(fh);
if (pclose(fh) != 0)
{
unlink(tmp_name);
return 1;
}
unlink(tmp_name);
fh = fopen(inc_name, "w");
fprintf(fh, "; generated by linker\r\n");
l = strtok(map_buf, "\n");
i = 0;
do {
if (l == NULL)
break;
if (address == 0)
sscanf(l, "%X", &address);
if (strstr(l, "Section .text"))
i = 1;
if (i && sscanf(l, "%*X %X %s", &a, label) == 2)
{
if (strstr(l, ".") == NULL)
{
fprintf(fh, "%%define %-32s 0x%08X\r\n", label, a);
update_annotations(label, a);
}
}
} while((l = strtok(NULL, "\n")));
fclose(fh);
free(map_buf);
if (!address)
{
fprintf(stderr, "linker: ORG not found in map\n");
return 1;
}
exe = fopen(exe_name, "rb+");
if (!exe)
{
perror(exe_name);
return 1;
}
fseek(exe, 0L, SEEK_END);
exe_length = ftell(exe);
rewind(exe);
exe_data = malloc(exe_length);
if (fread(exe_data, exe_length, 1, exe) != 1)
{
fclose(exe);
perror("linker: error reading executable");
return 1;
}
rewind(exe);
patch = fopen(out_name, "rb");
if (!patch)
{
fclose(exe);
perror(out_name);
unlink(out_name);
return 1;
}
fseek(patch, 0L, SEEK_END);
patch_length = ftell(patch);
rewind(patch);
/* ignore empty patches */
if (patch_length == 0)
{
free(exe_data);
fclose(exe);
return 0;
}
patch_data = malloc(patch_length);
if (fread(patch_data, patch_length, 1, patch) != 1)
{
fclose(exe);
fclose(patch);
unlink(out_name);
perror("linker: error reading patch");
return 1;
}
fclose(patch);
unlink(out_name);
if (!patch_image(exe_data, (unsigned int)address, patch_data, patch_length))
{
fprintf(stderr, "linker: memory address 0x%08X not found in %s\n", (unsigned int)address, exe_name);
return 1;
}
printf("PATCH %8d bytes -> %8X\n", patch_length, address);
/* create annotation patches */
for (i = 0; i < 512; i++)
{
struct annotation *ann = &annotations[i];
if (ann->type == NULL)
break;
if ((strcmp(ann->type, "hook") == 0 || strcmp(ann->type, "jmp") == 0) && ann->argc >= 2)
{
unsigned int from = strtol(ann->argv[0], NULL, 0);
unsigned int to = strtol(ann->argv[1], NULL, 0);
if (abs(to - from) < 128)
{
unsigned char buf[] = { 0xEB, 0x00 };
*(signed char *)(buf + 1) = to - from - 2;
if (!patch_image(exe_data, from, buf, sizeof buf))
{
fprintf(stderr, "linker: memory address 0x%08X not found in %s\n", (unsigned int)address, exe_name);
return 1;
}
printf("%-12s %8X -> %8X\n", "JMP SHORT", from, to);
}
else
{
unsigned char buf[] = { 0xE9, 0x00, 0x00, 0x00, 0x00 };
*(signed int *)(buf + 1) = to - from - 5;
if (!patch_image(exe_data, from, buf, sizeof buf))
{
fprintf(stderr, "linker: memory address 0x%08X not found in %s\n", (unsigned int)address, exe_name);
return 1;
}
printf("%-12s %8X -> %8X\n", "JMP", from, to);
}
}
else if (strcmp(ann->type, "call") == 0 && ann->argc >= 2)
{
unsigned int from = strtol(ann->argv[0], NULL, 0);
unsigned int to = strtol(ann->argv[1], NULL, 0);
unsigned char buf[] = { 0xE8, 0x00, 0x00, 0x00, 0x00 };
*(signed int *)(buf + 1) = to - from - 5;
if (!patch_image(exe_data, from, buf, sizeof buf))
{
fprintf(stderr, "linker: memory address 0x%08X not found in %s\n", (unsigned int)address, exe_name);
return 1;
}
printf("%-12s %8X -> %8X\n", "CALL", from, to);
}
else if (strcmp(ann->type, "clear") == 0 && ann->argc >= 3)
{
unsigned int from = strtol(ann->argv[0], NULL, 0);
unsigned int character = strtol(ann->argv[1], NULL, 0);
unsigned int to = strtol(ann->argv[2], NULL, 0);
unsigned int length = to - from;
char *zbuf = malloc(length);
if (!zbuf)
{
fprintf(stderr, "linker: out of memory when allocating %d for zbuf\n", length);
return 1;
}
memset(zbuf, (char)character, length);
if (!patch_image(exe_data, from, zbuf, length))
{
fprintf(stderr, "linker: memory address 0x%08X not found in %s\n", (unsigned int)from, exe_name);
return 1;
}
free(zbuf);
printf("CLEAR %8d bytes -> %8X\n", length, from);
}
else
{
fprintf(stderr, "linker: warning: unknown annotation \"%s\"\n", ann->type);
}
}
if (fwrite(exe_data, exe_length, 1, exe) != 1)
{
perror("linker: error writing to executable file");
return 1;
}
free(exe_data);
free(patch_data);
fclose(exe);
return 0;
}
