diff options
Diffstat (limited to 'linker/linker.cpp')
| -rw-r--r-- | linker/linker.cpp | 187 |
1 files changed, 126 insertions, 61 deletions
diff --git a/linker/linker.cpp b/linker/linker.cpp index b8dd216e7..522d5dc1a 100644 --- a/linker/linker.cpp +++ b/linker/linker.cpp @@ -186,7 +186,9 @@ static const char* const* g_default_ld_paths; static std::vector<std::string> g_ld_preload_names; static bool g_public_namespace_initialized; -static soinfo_list_t g_public_namespace; + +// TODO (dimitry): Remove once interface between libnativeloader and the linker is updated +static std::unordered_set<std::string> g_public_namespace_sonames; #if STATS struct linker_stats_t { @@ -525,7 +527,8 @@ class LoadTask { static deleter_t deleter; - static LoadTask* create(const char* name, soinfo* needed_by, + static LoadTask* create(const char* name, + soinfo* needed_by, std::unordered_map<const soinfo*, ElfReader>* readers_map) { LoadTask* ptr = TypeBasedAllocator<LoadTask>::alloc(); return new (ptr) LoadTask(name, needed_by, readers_map); @@ -616,7 +619,8 @@ class LoadTask { } private: - LoadTask(const char* name, soinfo* needed_by, + LoadTask(const char* name, + soinfo* needed_by, std::unordered_map<const soinfo*, ElfReader>* readers_map) : name_(name), needed_by_(needed_by), si_(nullptr), fd_(-1), close_fd_(false), file_offset_(0), elf_readers_map_(readers_map), @@ -1094,14 +1098,6 @@ static bool load_library(android_namespace_t* ns, soinfo* si = ns->soinfo_list().find_if(predicate); - // check public namespace - if (si == nullptr) { - si = g_public_namespace.find_if(predicate); - if (si != nullptr) { - ns->add_soinfo(si); - } - } - if (si != nullptr) { TRACE("library \"%s\" is already loaded under different name/path \"%s\" - " "will return existing soinfo", name, si->get_realpath()); @@ -1117,6 +1113,9 @@ static bool load_library(android_namespace_t* ns, if (!ns->is_accessible(realpath)) { // TODO(dimitry): workaround for http://b/26394120 - the grey-list + + // TODO(dimitry) before O release: add a namespace attribute to have this enabled + // only for classloader-namespaces const soinfo* needed_by = task->is_dt_needed() ? task->get_needed_by() : nullptr; if (is_greylisted(name, needed_by)) { // print warning only if needed by non-system library @@ -1249,11 +1248,79 @@ static bool find_loaded_library_by_soname(android_namespace_t* ns, }); } +static std::string resolve_soname(const std::string& name) { + // We assume that soname equals to basename here + + // TODO(dimitry): consider having honest absolute-path -> soname resolution + // note that since we might end up refusing to load this library because + // it is not in shared libs list we need to get the soname without actually loading + // the library. + // + // On the other hand there are several places where we already assume that + // soname == basename in particular for any not-loaded library mentioned + // in DT_NEEDED list. + return basename(name.c_str()); +} + + +static bool find_library_in_linked_namespace(const android_namespace_link_t& namespace_link, + LoadTask* task, + int rtld_flags) { + android_namespace_t* ns = namespace_link.linked_namespace(); + + soinfo* candidate; + bool loaded = false; + + std::string soname; + if (find_loaded_library_by_soname(ns, task->get_name(), &candidate)) { + loaded = true; + soname = candidate->get_soname(); + } else { + soname = resolve_soname(task->get_name()); + } + + if (!namespace_link.is_accessible(soname.c_str())) { + // the library is not accessible via namespace_link + return false; + } + + // if library is already loaded - return it + if (loaded) { + task->set_soinfo(candidate); + return true; + } + + // try to load the library - once namespace boundary is crossed + // we need to load a library within separate load_group + // to avoid using symbols from foreign namespace while. + // + // All symbols during relocation should be resolved within a + // namespace to preserve library locality to a namespace. + const char* name = task->get_name(); + if (find_libraries(ns, + task->get_needed_by(), + &name, + 1, + &candidate, + nullptr /* ld_preloads */, + 0 /* ld_preload_count*/, + rtld_flags, + nullptr /* extinfo*/, + false /* add_as_children */, + false /* search_linked_namespaces */)) { + task->set_soinfo(candidate); + return true; + } + + return false; +} + static bool find_library_internal(android_namespace_t* ns, LoadTask* task, ZipArchiveCache* zip_archive_cache, LoadTaskList* load_tasks, - int rtld_flags) { + int rtld_flags, + bool search_linked_namespaces) { soinfo* candidate; if (find_loaded_library_by_soname(ns, task->get_name(), &candidate)) { @@ -1261,25 +1328,27 @@ static bool find_library_internal(android_namespace_t* ns, return true; } - if (ns != &g_default_namespace) { - // check public namespace - candidate = g_public_namespace.find_if([&](soinfo* si) { - return strcmp(task->get_name(), si->get_soname()) == 0; - }); - - if (candidate != nullptr) { - ns->add_soinfo(candidate); - task->set_soinfo(candidate); - return true; - } - } - // Library might still be loaded, the accurate detection // of this fact is done by load_library. TRACE("[ \"%s\" find_loaded_library_by_soname failed (*candidate=%s@%p). Trying harder...]", task->get_name(), candidate == nullptr ? "n/a" : candidate->get_realpath(), candidate); - return load_library(ns, task, zip_archive_cache, load_tasks, rtld_flags); + if (load_library(ns, task, zip_archive_cache, load_tasks, rtld_flags)) { + return true; + } + + if (search_linked_namespaces) { + // if a library was not found - look into linked namespaces + for (auto& linked_namespace : ns->linked_namespaces()) { + if (find_library_in_linked_namespace(linked_namespace, + task, + rtld_flags)) { + return true; + } + } + } + + return false; } static void soinfo_unload(soinfo* si); @@ -1344,7 +1413,8 @@ bool find_libraries(android_namespace_t* ns, size_t ld_preloads_count, int rtld_flags, const android_dlextinfo* extinfo, - bool add_as_children) { + bool add_as_children, + bool search_linked_namespaces) { // Step 0: prepare. LoadTaskList load_tasks; std::unordered_map<const soinfo*, ElfReader> readers_map; @@ -1396,7 +1466,12 @@ bool find_libraries(android_namespace_t* ns, task->set_extinfo(is_dt_needed ? nullptr : extinfo); task->set_dt_needed(is_dt_needed); - if(!find_library_internal(ns, task, &zip_archive_cache, &load_tasks, rtld_flags)) { + if (!find_library_internal(ns, + task, + &zip_archive_cache, + &load_tasks, + rtld_flags, + search_linked_namespaces || is_dt_needed)) { return false; } @@ -1404,10 +1479,10 @@ bool find_libraries(android_namespace_t* ns, if (is_dt_needed) { needed_by->add_child(si); - } - if (si->is_linked()) { - si->increment_ref_count(); + if (si->is_linked()) { + si->increment_ref_count(); + } } // When ld_preloads is not null, the first @@ -1471,10 +1546,6 @@ bool find_libraries(android_namespace_t* ns, return true; }); - // We need to increment ref_count in case - // the root of the local group was not linked. - bool was_local_group_root_linked = local_group.front()->is_linked(); - bool linked = local_group.visit([&](soinfo* si) { if (!si->is_linked()) { if (!si->link_image(global_group, local_group, extinfo) || @@ -1496,10 +1567,6 @@ bool find_libraries(android_namespace_t* ns, failure_guard.disable(); } - if (!was_local_group_root_linked) { - local_group.front()->increment_ref_count(); - } - return linked; } @@ -1511,11 +1578,22 @@ static soinfo* find_library(android_namespace_t* ns, if (name == nullptr) { si = solist_get_somain(); - } else if (!find_libraries(ns, needed_by, &name, 1, &si, nullptr, 0, rtld_flags, - extinfo, /* add_as_children */ false)) { + } else if (!find_libraries(ns, + needed_by, + &name, + 1, + &si, + nullptr, + 0, + rtld_flags, + extinfo, + false /* add_as_children */, + true /* search_linked_namespaces */)) { return nullptr; } + si->increment_ref_count(); + return si; } @@ -1934,28 +2012,11 @@ bool init_namespaces(const char* public_ns_sonames, const char* anon_ns_library_ return false; } - std::vector<std::string> sonames = android::base::Split(public_ns_sonames, ":"); + auto sonames = android::base::Split(public_ns_sonames, ":"); ProtectedDataGuard guard; - auto failure_guard = make_scope_guard([&]() { - g_public_namespace.clear(); - }); - - for (const auto& soname : sonames) { - soinfo* candidate = nullptr; - - find_loaded_library_by_soname(&g_default_namespace, soname.c_str(), &candidate); - - if (candidate == nullptr) { - DL_ERR("error initializing public namespace: a library with soname \"%s\"" - " was not found in the default namespace", soname.c_str()); - return false; - } - - candidate->set_nodelete(); - g_public_namespace.push_back(candidate); - } + g_public_namespace_sonames = std::unordered_set<std::string>(sonames.begin(), sonames.end()); g_public_namespace_initialized = true; @@ -1971,8 +2032,8 @@ bool init_namespaces(const char* public_ns_sonames, const char* anon_ns_library_ g_public_namespace_initialized = false; return false; } + g_anonymous_namespace = anon_ns; - failure_guard.disable(); return true; } @@ -2028,6 +2089,10 @@ android_namespace_t* create_namespace(const void* caller_addr, add_soinfos_to_namespace(get_shared_group(parent_namespace), ns); } + // link it to default namespace + // TODO (dimitry): replace this with user-supplied link once interface is updated + ns->add_linked_namespace(&g_default_namespace, g_public_namespace_sonames); + return ns; } |