static
int get_strtab_symtab(struct dl_phdr_info* info, size_t size, void* ptr)
{
auto* data = reinterpret_cast<Data*>(ptr);
if (data->index != data->target) {
data->index += 1;
return 0;
}
#if DEBUG_LOG
std::cout << "name " << info->dlpi_name << std::endl;
#endif
ElfW(Dyn)* dynamic{nullptr};
ElfW(Addr) bias{0};
bool first_phdr{true};
for(size_t i = 0; i < info->dlpi_phnum; ++i) {
if (info->dlpi_phdr[i].p_type == PT_LOAD and first_phdr) {
first_phdr = false;
bias = info->dlpi_addr - info->dlpi_phdr[i].p_vaddr;
}
if (info->dlpi_phdr[i].p_type == PT_DYNAMIC) {
dynamic = reinterpret_cast<ElfW(Dyn)*>(info->dlpi_phdr[i].p_vaddr + bias);
}
}
for (ElfW(Dyn)* d = dynamic; d->d_tag != DT_NULL; ++d) {
switch(d->d_tag) {
case DT_SYMTAB:
data->symtab = reinterpret_cast<ElfW(Sym)*>(bias + d->d_un.d_ptr);
break;
case DT_STRTAB:
data->strtab = reinterpret_cast<const char*>(bias + d->d_un.d_ptr);
break;
}
}
data->base = info->dlpi_addr;
data->name = info->dlpi_name;
#if DEBUG_LOG
std::cout << "strtab " << (void*)data->strtab << std::endl;
std::cout << "symtab " << (void*)data->symtab << std::endl;
std::cout << "phdr " << info->dlpi_phdr << std::endl;
std::cout << "dynamic " << dynamic << std::endl;
std::cout << "bias " << (void*)bias << std::endl;
#endif
return 1;
}
static
Data get_soinfo_next_ptr(size_t target)
{
Data data { nullptr, nullptr, target, 0 };
dl_iterate_phdr(get_strtab_symtab, &data);
FILE* fp = fopen("/proc/self/maps", "re");
if (fp == nullptr) {
return { 0, 0, 0, 0, 0, {}, 0 };
}
char line[BUFSIZ];
while(fgets(line, sizeof(line), fp) != nullptr) {
uintptr_t begin;
uintptr_t end;
char r,w;
if (sscanf(line, "%" SCNxPTR "-%" SCNxPTR " %c%c", &begin, &end, &r, &w) == 4) {
if (r == 'r') {
void* ptr = memmem(reinterpret_cast<void*>(begin), end - begin, &data, sizeof(void*) * 2);
if (ptr != nullptr and ptr != &data) {
#if DEBUG_LOG && 0
printf("%s", line);
for (int i = 0; i < 8; ++i) {
std::cout << (reinterpret_cast<void**>(ptr)[-i+1]) << std::endl;
}
#endif
data.next_ptr = &reinterpret_cast<void**>(ptr)[-2];
break;
}
}
}
}
fclose(fp);
return data;
}
