Introducing linker namespaces

Bug: http://b/22548808
Change-Id: Ia3af3c0a167f1d16447a3d83bb045d143319b1e1
This commit is contained in:
Dmitriy Ivanov
2015-10-29 17:01:24 -07:00
parent ffe5c24c86
commit 42d5fcb9f4
26 changed files with 1122 additions and 152 deletions

View File

@@ -70,11 +70,55 @@ extern void __libc_init_AT_SECURE(KernelArgumentBlock&);
#undef ELF_ST_TYPE
#define ELF_ST_TYPE(x) (static_cast<uint32_t>(x) & 0xf)
struct android_namespace_t {
public:
android_namespace_t() : name_(nullptr), is_isolated_(false) {}
const char* get_name() const { return name_; }
void set_name(const char* name) { name_ = name; }
bool is_isolated() const { return is_isolated_; }
void set_isolated(bool isolated) { is_isolated_ = isolated; }
const std::vector<std::string>& get_ld_library_paths() const {
return ld_library_paths_;
}
void set_ld_library_paths(std::vector<std::string>&& library_paths) {
ld_library_paths_ = library_paths;
}
const std::vector<std::string>& get_default_library_paths() const {
return default_library_paths_;
}
void set_default_library_paths(std::vector<std::string>&& library_paths) {
default_library_paths_ = library_paths;
}
soinfo::soinfo_list_t& soinfo_list() { return soinfo_list_; }
// For isolated namespaces - checks if the file is on the search path;
// always returns true for not isolated namespace.
bool is_accessible(const std::string& path);
private:
const char* name_;
bool is_isolated_;
std::vector<std::string> ld_library_paths_;
std::vector<std::string> default_library_paths_;
soinfo::soinfo_list_t soinfo_list_;
DISALLOW_COPY_AND_ASSIGN(android_namespace_t);
};
android_namespace_t g_default_namespace;
static ElfW(Addr) get_elf_exec_load_bias(const ElfW(Ehdr)* elf);
static LinkerTypeAllocator<soinfo> g_soinfo_allocator;
static LinkerTypeAllocator<LinkedListEntry<soinfo>> g_soinfo_links_allocator;
static LinkerTypeAllocator<android_namespace_t> g_namespace_allocator;
static soinfo* solist;
static soinfo* sonext;
static soinfo* somain; // main process, always the one after libdl_info
@@ -107,14 +151,15 @@ static const char* const kAsanDefaultLdPaths[] = {
static const ElfW(Versym) kVersymNotNeeded = 0;
static const ElfW(Versym) kVersymGlobal = 1;
static const char* const kZipFileSeparator = "!/";
static const char* const* g_default_ld_paths;
static std::vector<std::string> g_ld_library_paths;
static std::vector<std::string> g_ld_preload_names;
static std::vector<soinfo*> g_ld_preloads;
static bool g_public_namespace_initialized;
static soinfo::soinfo_list_t g_public_namespace;
__LIBC_HIDDEN__ int g_ld_debug_verbosity;
__LIBC_HIDDEN__ abort_msg_t* g_abort_message = nullptr; // For debuggerd.
@@ -247,6 +292,26 @@ void notify_gdb_of_libraries() {
rtld_db_dlactivity();
}
bool android_namespace_t::is_accessible(const std::string& file) {
if (!is_isolated_) {
return true;
}
for (const auto& dir : ld_library_paths_) {
if (file_is_in_dir(file, dir)) {
return true;
}
}
for (const auto& dir : default_library_paths_) {
if (file_is_in_dir(file, dir)) {
return true;
}
}
return false;
}
LinkedListEntry<soinfo>* SoinfoListAllocator::alloc() {
return g_soinfo_links_allocator.alloc();
}
@@ -255,18 +320,22 @@ void SoinfoListAllocator::free(LinkedListEntry<soinfo>* entry) {
g_soinfo_links_allocator.free(entry);
}
static soinfo* soinfo_alloc(const char* name, struct stat* file_stat,
off64_t file_offset, uint32_t rtld_flags) {
static soinfo* soinfo_alloc(android_namespace_t* ns, const char* name,
struct stat* file_stat, off64_t file_offset,
uint32_t rtld_flags) {
if (strlen(name) >= PATH_MAX) {
DL_ERR("library name \"%s\" too long", name);
return nullptr;
}
soinfo* si = new (g_soinfo_allocator.alloc()) soinfo(name, file_stat, file_offset, rtld_flags);
soinfo* si = new (g_soinfo_allocator.alloc()) soinfo(ns, name, file_stat,
file_offset, rtld_flags);
sonext->next = si;
sonext = si;
ns->soinfo_list().push_back(si);
TRACE("name %s: allocated soinfo @ %p", name, si);
return si;
}
@@ -307,33 +376,130 @@ static void soinfo_free(soinfo* si) {
sonext = prev;
}
// remove from the namespace
si->get_namespace()->soinfo_list().remove_if([&](soinfo* candidate) {
return si == candidate;
});
si->~soinfo();
g_soinfo_allocator.free(si);
}
static void parse_path(const char* path, const char* delimiters,
// For every path element this function checks of it exists, and is a directory,
// and normalizes it:
// 1. For regular path it converts it to realpath()
// 2. For path in a zip file it uses realpath on the zipfile
// normalizes entry name by calling normalize_path function.
static void resolve_paths(std::vector<std::string>& paths,
std::vector<std::string>* resolved_paths) {
resolved_paths->clear();
for (const auto& path : paths) {
char resolved_path[PATH_MAX];
const char* original_path = path.c_str();
if (realpath(original_path, resolved_path) != nullptr) {
struct stat s;
if (stat(resolved_path, &s) == 0) {
if (S_ISDIR(s.st_mode)) {
resolved_paths->push_back(resolved_path);
} else {
DL_WARN("Warning: \"%s\" is not a directory (excluding from path)", resolved_path);
continue;
}
} else {
DL_WARN("Warning: cannot stat file \"%s\": %s", resolved_path, strerror(errno));
continue;
}
} else {
std::string zip_path;
std::string entry_path;
std::string normalized_path;
if (!normalize_path(original_path, &normalized_path)) {
DL_WARN("Warning: unable to normalize \"%s\"", original_path);
continue;
}
if (parse_zip_path(normalized_path.c_str(), &zip_path, &entry_path)) {
if (realpath(zip_path.c_str(), resolved_path) == nullptr) {
DL_WARN("Warning: unable to resolve \"%s\": %s", zip_path.c_str(), strerror(errno));
continue;
}
ZipArchiveHandle handle = nullptr;
if (OpenArchive(resolved_path, &handle) != 0) {
DL_WARN("Warning: unable to open zip archive: %s", resolved_path);
continue;
}
// Check if zip-file has a dir with entry_path name
void* cookie = nullptr;
std::string prefix_str = entry_path + "/";
ZipString prefix(prefix_str.c_str());
ZipEntry out_data;
ZipString out_name;
int32_t error_code;
if ((error_code = StartIteration(handle, &cookie, &prefix, nullptr)) != 0) {
DL_WARN("Unable to iterate over zip-archive entries \"%s\";"
" error code: %d", zip_path.c_str(), error_code);
continue;
}
if (Next(cookie, &out_data, &out_name) != 0) {
DL_WARN("Unable to find entries starting with \"%s\" in \"%s\"",
prefix_str.c_str(), zip_path.c_str());
continue;
}
auto zip_guard = make_scope_guard([&]() {
if (cookie != nullptr) {
EndIteration(cookie);
}
CloseArchive(handle);
});
resolved_paths->push_back(std::string(resolved_path) + kZipFileSeparator + entry_path);
}
}
}
}
static void split_path(const char* path, const char* delimiters,
std::vector<std::string>* paths) {
paths->clear();
if (path != nullptr) {
*paths = android::base::Split(path, delimiters);
}
}
static void parse_path(const char* path, const char* delimiters,
std::vector<std::string>* resolved_paths) {
std::vector<std::string> paths;
split_path(path, delimiters, &paths);
resolve_paths(paths, resolved_paths);
}
static void parse_LD_LIBRARY_PATH(const char* path) {
parse_path(path, ":", &g_ld_library_paths);
std::vector<std::string> ld_libary_paths;
parse_path(path, ":", &ld_libary_paths);
g_default_namespace.set_ld_library_paths(std::move(ld_libary_paths));
}
void soinfo::set_dt_runpath(const char* path) {
if (!has_min_version(2)) {
if (!has_min_version(3)) {
return;
}
parse_path(path, ":", &dt_runpath_);
std::vector<std::string> runpaths;
split_path(path, ":", &runpaths);
std::string origin = dirname(get_realpath());
// FIXME: add $LIB and $PLATFORM.
std::pair<std::string, std::string> substs[] = {{"ORIGIN", origin}};
for (auto&& s : dt_runpath_) {
for (auto&& s : runpaths) {
size_t pos = 0;
while (pos < s.size()) {
pos = s.find("$", pos);
@@ -356,11 +522,16 @@ void soinfo::set_dt_runpath(const char* path) {
++pos;
}
}
resolve_paths(runpaths, &dt_runpath_);
}
static void parse_LD_PRELOAD(const char* path) {
// We have historically supported ':' as well as ' ' in LD_PRELOAD.
parse_path(path, " :", &g_ld_preload_names);
g_ld_preload_names.clear();
if (path != nullptr) {
// We have historically supported ':' as well as ' ' in LD_PRELOAD.
g_ld_preload_names = android::base::Split(path, " :");
}
}
static bool realpath_fd(int fd, std::string* realpath) {
@@ -688,8 +859,9 @@ bool soinfo::elf_lookup(SymbolName& symbol_name,
return true;
}
soinfo::soinfo(const char* realpath, const struct stat* file_stat,
off64_t file_offset, int rtld_flags) {
soinfo::soinfo(android_namespace_t* ns, const char* realpath,
const struct stat* file_stat, off64_t file_offset,
int rtld_flags) {
memset(this, 0, sizeof(*this));
if (realpath != nullptr) {
@@ -706,6 +878,7 @@ soinfo::soinfo(const char* realpath, const struct stat* file_stat,
}
this->rtld_flags_ = rtld_flags;
this->namespace_ = ns;
}
@@ -857,6 +1030,7 @@ class ProtectedDataGuard {
void protect_data(int protection) {
g_soinfo_allocator.protect_all(protection);
g_soinfo_links_allocator.protect_all(protection);
g_namespace_allocator.protect_all(protection);
}
static size_t ref_count_;
@@ -1096,7 +1270,7 @@ const ElfW(Sym)* dlsym_handle_lookup(soinfo* si, soinfo** found, const char* nam
// libraries and they are loaded in breath-first (correct) order we can just execute
// dlsym(RTLD_DEFAULT, ...); instead of doing two stage lookup.
if (si == somain) {
return dlsym_linear_lookup(name, found, nullptr, RTLD_DEFAULT);
return dlsym_linear_lookup(&g_default_namespace, name, found, nullptr, RTLD_DEFAULT);
}
SymbolName symbol_name(name);
@@ -1108,24 +1282,29 @@ const ElfW(Sym)* dlsym_handle_lookup(soinfo* si, soinfo** found, const char* nam
beginning of the global solist. Otherwise the search starts at the
specified soinfo (for RTLD_NEXT).
*/
const ElfW(Sym)* dlsym_linear_lookup(const char* name,
const ElfW(Sym)* dlsym_linear_lookup(android_namespace_t* ns,
const char* name,
soinfo** found,
soinfo* caller,
void* handle) {
SymbolName symbol_name(name);
soinfo* start = solist;
soinfo::soinfo_list_t& soinfo_list = ns->soinfo_list();
soinfo::soinfo_list_t::iterator start = soinfo_list.begin();
if (handle == RTLD_NEXT) {
if (caller == nullptr) {
return nullptr;
} else {
start = caller->next;
soinfo::soinfo_list_t::iterator it = soinfo_list.find(caller);
CHECK (it != soinfo_list.end());
start = ++it;
}
}
const ElfW(Sym)* s = nullptr;
for (soinfo* si = start; si != nullptr; si = si->next) {
for (soinfo::soinfo_list_t::iterator it = start, end = soinfo_list.end(); it != end; ++it) {
soinfo* si = *it;
// Do not skip RTLD_LOCAL libraries in dlsym(RTLD_DEFAULT, ...)
// if the library is opened by application with target api level <= 22
// See http://b/21565766
@@ -1337,35 +1516,13 @@ static bool format_path(char* buf, size_t buf_size, const char* path, const char
return true;
}
static int open_library_on_default_path(const char* name, off64_t* file_offset, std::string* realpath) {
for (size_t i = 0; g_default_ld_paths[i] != nullptr; ++i) {
char buf[512];
if (!format_path(buf, sizeof(buf), g_default_ld_paths[i], name)) {
continue;
}
int fd = TEMP_FAILURE_RETRY(open(buf, O_RDONLY | O_CLOEXEC));
if (fd != -1) {
*file_offset = 0;
if (!realpath_fd(fd, realpath)) {
PRINT("warning: unable to get realpath for the library \"%s\". Will use given path.", buf);
*realpath = buf;
}
return fd;
}
}
return -1;
}
static int open_library_on_paths(ZipArchiveCache* zip_archive_cache,
const char* name, off64_t* file_offset,
const std::vector<std::string>& paths,
std::string* realpath) {
for (const auto& path_str : paths) {
for (const auto& path : paths) {
char buf[512];
const char* const path = path_str.c_str();
if (!format_path(buf, sizeof(buf), path, name)) {
if (!format_path(buf, sizeof(buf), path.c_str(), name)) {
continue;
}
@@ -1393,39 +1550,49 @@ static int open_library_on_paths(ZipArchiveCache* zip_archive_cache,
return -1;
}
static int open_library(ZipArchiveCache* zip_archive_cache,
static int open_library(android_namespace_t* ns,
ZipArchiveCache* zip_archive_cache,
const char* name, soinfo *needed_by,
off64_t* file_offset, std::string* realpath) {
TRACE("[ opening %s ]", name);
// If the name contains a slash, we should attempt to open it directly and not search the paths.
if (strchr(name, '/') != nullptr) {
int fd = -1;
if (strstr(name, kZipFileSeparator) != nullptr) {
int fd = open_library_in_zipfile(zip_archive_cache, name, file_offset, realpath);
fd = open_library_in_zipfile(zip_archive_cache, name, file_offset, realpath);
}
if (fd == -1) {
fd = TEMP_FAILURE_RETRY(open(name, O_RDONLY | O_CLOEXEC));
if (fd != -1) {
return fd;
*file_offset = 0;
if (!realpath_fd(fd, realpath)) {
PRINT("warning: unable to get realpath for the library \"%s\". Will use given path.", name);
*realpath = name;
}
}
}
int fd = TEMP_FAILURE_RETRY(open(name, O_RDONLY | O_CLOEXEC));
if (fd != -1) {
*file_offset = 0;
if (!realpath_fd(fd, realpath)) {
PRINT("warning: unable to get realpath for the library \"%s\". Will use given path.", name);
*realpath = name;
}
if (fd != -1 && !ns->is_accessible(*realpath)) {
fd = -1;
}
return fd;
}
// Otherwise we try LD_LIBRARY_PATH first, and fall back to the built-in well known paths.
int fd = open_library_on_paths(zip_archive_cache, name, file_offset, g_ld_library_paths, realpath);
// Otherwise we try LD_LIBRARY_PATH first, and fall back to the default library path
int fd = open_library_on_paths(zip_archive_cache, name, file_offset, ns->get_ld_library_paths(), realpath);
if (fd == -1 && needed_by != nullptr) {
fd = open_library_on_paths(zip_archive_cache, name, file_offset, needed_by->get_dt_runpath(), realpath);
// Check if the library is accessible
if (fd != -1 && !ns->is_accessible(*realpath)) {
fd = -1;
}
}
if (fd == -1) {
fd = open_library_on_default_path(name, file_offset, realpath);
fd = open_library_on_paths(zip_archive_cache, name, file_offset, ns->get_default_library_paths(), realpath);
}
return fd;
@@ -1464,7 +1631,8 @@ static void for_each_dt_needed(const ElfReader& elf_reader, F action) {
}
}
static bool load_library(LoadTask* task,
static bool load_library(android_namespace_t* ns,
LoadTask* task,
LoadTaskList* load_tasks,
int rtld_flags,
const std::string& realpath) {
@@ -1495,18 +1663,30 @@ static bool load_library(LoadTask* task,
// Check for symlink and other situations where
// file can have different names, unless ANDROID_DLEXT_FORCE_LOAD is set
if (extinfo == nullptr || (extinfo->flags & ANDROID_DLEXT_FORCE_LOAD) == 0) {
for (soinfo* si = solist; si != nullptr; si = si->next) {
if (si->get_st_dev() != 0 &&
si->get_st_ino() != 0 &&
si->get_st_dev() == file_stat.st_dev &&
si->get_st_ino() == file_stat.st_ino &&
si->get_file_offset() == file_offset) {
TRACE("library \"%s\" is already loaded under different name/path \"%s\" - "
"will return existing soinfo", name, si->get_realpath());
task->set_soinfo(si);
return true;
auto predicate = [&](soinfo* si) {
return si->get_st_dev() != 0 &&
si->get_st_ino() != 0 &&
si->get_st_dev() == file_stat.st_dev &&
si->get_st_ino() == file_stat.st_ino &&
si->get_file_offset() == file_offset;
};
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->soinfo_list().push_back(si);
}
}
if (si != nullptr) {
TRACE("library \"%s\" is already loaded under different name/path \"%s\" - "
"will return existing soinfo", name, si->get_realpath());
task->set_soinfo(si);
return true;
}
}
if ((rtld_flags & RTLD_NOLOAD) != 0) {
@@ -1514,7 +1694,7 @@ static bool load_library(LoadTask* task,
return false;
}
soinfo* si = soinfo_alloc(realpath.c_str(), &file_stat, file_offset, rtld_flags);
soinfo* si = soinfo_alloc(ns, realpath.c_str(), &file_stat, file_offset, rtld_flags);
if (si == nullptr) {
return false;
}
@@ -1550,7 +1730,8 @@ static bool load_library(LoadTask* task,
}
static bool load_library(LoadTask* task,
static bool load_library(android_namespace_t* ns,
LoadTask* task,
ZipArchiveCache* zip_archive_cache,
LoadTaskList* load_tasks,
int rtld_flags) {
@@ -1574,11 +1755,11 @@ static bool load_library(LoadTask* task,
task->set_fd(extinfo->library_fd, false);
task->set_file_offset(file_offset);
return load_library(task, load_tasks, rtld_flags, realpath);
return load_library(ns, task, load_tasks, rtld_flags, realpath);
}
// Open the file.
int fd = open_library(zip_archive_cache, name, needed_by, &file_offset, &realpath);
int fd = open_library(ns, zip_archive_cache, name, needed_by, &file_offset, &realpath);
if (fd == -1) {
DL_ERR("library \"%s\" not found", name);
return false;
@@ -1587,14 +1768,15 @@ static bool load_library(LoadTask* task,
task->set_fd(fd, true);
task->set_file_offset(file_offset);
return load_library(task, load_tasks, rtld_flags, realpath);
return load_library(ns, task, load_tasks, rtld_flags, realpath);
}
// Returns true if library was found and false in 2 cases
// 1. The library was found but loaded under different target_sdk_version
// (*candidate != nullptr)
// 1. (for default namespace only) The library was found but loaded under different
// target_sdk_version (*candidate != nullptr)
// 2. The library was not found by soname (*candidate is nullptr)
static bool find_loaded_library_by_soname(const char* name, soinfo** candidate) {
static bool find_loaded_library_by_soname(android_namespace_t* ns,
const char* name, soinfo** candidate) {
*candidate = nullptr;
// Ignore filename with path.
@@ -1604,7 +1786,7 @@ static bool find_loaded_library_by_soname(const char* name, soinfo** candidate)
uint32_t target_sdk_version = get_application_target_sdk_version();
for (soinfo* si = solist; si != nullptr; si = si->next) {
return !ns->soinfo_list().visit([&](soinfo* si) {
const char* soname = si->get_soname();
if (soname != nullptr && (strcmp(name, soname) == 0)) {
// If the library was opened under different target sdk version
@@ -1614,36 +1796,52 @@ static bool find_loaded_library_by_soname(const char* name, soinfo** candidate)
// in any case.
bool is_libdl = si == solist;
if (is_libdl || (si->get_dt_flags_1() & DF_1_GLOBAL) != 0 ||
!si->is_linked() || si->get_target_sdk_version() == target_sdk_version) {
!si->is_linked() || si->get_target_sdk_version() == target_sdk_version ||
ns != &g_default_namespace) {
*candidate = si;
return true;
return false;
} else if (*candidate == nullptr) {
// for the different sdk version - remember the first library.
// for the different sdk version in the default namespace
// remember the first library.
*candidate = si;
}
}
}
return false;
return true;
});
}
static bool find_library_internal(LoadTask* task,
static bool find_library_internal(android_namespace_t* ns,
LoadTask* task,
ZipArchiveCache* zip_archive_cache,
LoadTaskList* load_tasks,
int rtld_flags) {
soinfo* candidate;
if (find_loaded_library_by_soname(task->get_name(), &candidate)) {
if (find_loaded_library_by_soname(ns, task->get_name(), &candidate)) {
task->set_soinfo(candidate);
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->soinfo_list().push_back(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 returned false (*candidate=%s@%p). Trying harder...]",
task->get_name(), candidate == nullptr ? "n/a" : candidate->get_realpath(), candidate);
if (load_library(task, zip_archive_cache, load_tasks, rtld_flags)) {
if (load_library(ns, task, zip_archive_cache, load_tasks, rtld_flags)) {
return true;
} else {
// In case we were unable to load the library but there
@@ -1667,13 +1865,13 @@ static void soinfo_unload(soinfo* si);
//
// This group consists of the main executable, LD_PRELOADs
// and libraries with the DF_1_GLOBAL flag set.
static soinfo::soinfo_list_t make_global_group() {
static soinfo::soinfo_list_t make_global_group(android_namespace_t* ns) {
soinfo::soinfo_list_t global_group;
for (soinfo* si = somain; si != nullptr; si = si->next) {
ns->soinfo_list().for_each([&](soinfo* si) {
if ((si->get_dt_flags_1() & DF_1_GLOBAL) != 0) {
global_group.push_back(si);
}
}
});
return global_group;
}
@@ -1690,7 +1888,8 @@ static void shuffle(std::vector<LoadTask*>* v) {
// not their transitive dependencies) as children of the start_with library.
// This is false when find_libraries is called for dlopen(), when newly loaded
// libraries must form a disjoint tree.
static bool find_libraries(soinfo* start_with,
static bool find_libraries(android_namespace_t* ns,
soinfo* start_with,
const char* const library_names[],
size_t library_names_count, soinfo* soinfos[],
std::vector<soinfo*>* ld_preloads,
@@ -1707,7 +1906,7 @@ static bool find_libraries(soinfo* start_with,
}
// Construct global_group.
soinfo::soinfo_list_t global_group = make_global_group();
soinfo::soinfo_list_t global_group = make_global_group(ns);
// If soinfos array is null allocate one on stack.
// The array is needed in case of failure; for example
@@ -1749,7 +1948,7 @@ static bool find_libraries(soinfo* start_with,
bool is_dt_needed = needed_by != nullptr && (needed_by != start_with || add_as_children);
task->set_extinfo(is_dt_needed ? nullptr : extinfo);
if(!find_library_internal(task, &zip_archive_cache, &load_tasks, rtld_flags)) {
if(!find_library_internal(ns, task, &zip_archive_cache, &load_tasks, rtld_flags)) {
return false;
}
@@ -1850,14 +2049,15 @@ static bool find_libraries(soinfo* start_with,
return linked;
}
static soinfo* find_library(const char* name, int rtld_flags,
static soinfo* find_library(android_namespace_t* ns,
const char* name, int rtld_flags,
const android_dlextinfo* extinfo,
soinfo* needed_by) {
soinfo* si;
if (name == nullptr) {
si = somain;
} else if (!find_libraries(needed_by, &name, 1, &si, nullptr, 0, rtld_flags,
} else if (!find_libraries(ns, needed_by, &name, 1, &si, nullptr, 0, rtld_flags,
extinfo, /* add_as_children */ false)) {
return nullptr;
}
@@ -1920,7 +2120,9 @@ static void soinfo_unload(soinfo* root) {
TRACE("deprecated (old format of soinfo): %s needs to unload %s",
si->get_realpath(), library_name);
soinfo* needed = find_library(library_name, RTLD_NOLOAD, nullptr, nullptr);
soinfo* needed = find_library(si->get_namespace(),
library_name, RTLD_NOLOAD, nullptr, nullptr);
if (needed != nullptr) {
// Not found: for example if symlink was deleted between dlopen and dlclose
// Since we cannot really handle errors at this point - print and continue.
@@ -1992,6 +2194,9 @@ soinfo* do_dlopen(const char* name, int flags, const android_dlextinfo* extinfo,
DL_ERR("invalid flags to dlopen: %x", flags);
return nullptr;
}
android_namespace_t* ns = caller->get_namespace();
if (extinfo != nullptr) {
if ((extinfo->flags & ~(ANDROID_DLEXT_VALID_FLAG_BITS)) != 0) {
DL_ERR("invalid extended flags to android_dlopen_ext: 0x%" PRIx64, extinfo->flags);
@@ -2011,13 +2216,22 @@ soinfo* do_dlopen(const char* name, int flags, const android_dlextinfo* extinfo,
"compatible with ANDROID_DLEXT_RESERVED_ADDRESS/ANDROID_DLEXT_RESERVED_ADDRESS_HINT");
return nullptr;
}
if ((extinfo->flags & ANDROID_DLEXT_USE_NAMESPACE) != 0) {
if (extinfo->library_namespace == nullptr) {
DL_ERR("ANDROID_DLEXT_USE_NAMESPACE is set but extinfo->library_namespace is null");
return nullptr;
}
ns = extinfo->library_namespace;
}
}
ProtectedDataGuard guard;
soinfo* si = find_library(name, flags, extinfo, caller);
soinfo* si = find_library(ns, name, flags, extinfo, caller);
if (si != nullptr) {
si->call_constructors();
}
return si;
}
@@ -2026,6 +2240,67 @@ void do_dlclose(soinfo* si) {
soinfo_unload(si);
}
bool init_public_namespace(const char* libs) {
CHECK(libs != nullptr);
if (g_public_namespace_initialized) {
DL_ERR("Public namespace has already been initialized.");
return false;
}
std::vector<std::string> sonames = android::base::Split(libs, ":");
ProtectedDataGuard guard;
auto failure_guard = make_scope_guard([&]() {
g_public_namespace.clear();
});
soinfo* candidate;
for (const auto& soname : sonames) {
if (!find_loaded_library_by_soname(&g_default_namespace, soname.c_str(), &candidate)) {
DL_ERR("Error initializing public namespace: \"%s\" was not found"
" in the default namespace", soname.c_str());
return false;
}
candidate->set_nodelete();
g_public_namespace.push_back(candidate);
}
failure_guard.disable();
g_public_namespace_initialized = true;
return true;
}
android_namespace_t* create_namespace(const char* name,
const char* ld_library_path,
const char* default_library_path,
bool is_isolated) {
if (!g_public_namespace_initialized) {
DL_ERR("Cannot create namespace: public namespace is not initialized.");
return nullptr;
}
ProtectedDataGuard guard;
std::vector<std::string> ld_library_paths;
std::vector<std::string> default_library_paths;
parse_path(ld_library_path, ":", &ld_library_paths);
parse_path(default_library_path, ":", &default_library_paths);
android_namespace_t* ns = new (g_namespace_allocator.alloc()) android_namespace_t();
ns->set_name(name);
ns->set_isolated(is_isolated);
ns->set_ld_library_paths(std::move(ld_library_paths));
ns->set_default_library_paths(std::move(default_library_paths));
// TODO(dimtiry): Should this be global group of caller's namespace?
auto global_group = make_global_group(&g_default_namespace);
std::copy(global_group.begin(), global_group.end(), std::back_inserter(ns->soinfo_list()));
return ns;
}
static ElfW(Addr) call_ifunc_resolver(ElfW(Addr) resolver_addr) {
typedef ElfW(Addr) (*ifunc_resolver_t)(void);
ifunc_resolver_t ifunc_resolver = reinterpret_cast<ifunc_resolver_t>(resolver_addr);
@@ -2694,6 +2969,10 @@ void soinfo::set_dt_flags_1(uint32_t dt_flags_1) {
}
}
void soinfo::set_nodelete() {
rtld_flags_ |= RTLD_NODELETE;
}
const char* soinfo::get_realpath() const {
#if defined(__work_around_b_24465209__)
if (has_min_version(2)) {
@@ -2760,13 +3039,21 @@ soinfo::soinfo_list_t& soinfo::get_parents() {
static std::vector<std::string> g_empty_runpath;
const std::vector<std::string>& soinfo::get_dt_runpath() const {
if (has_min_version(2)) {
if (has_min_version(3)) {
return dt_runpath_;
}
return g_empty_runpath;
}
android_namespace_t* soinfo::get_namespace() {
if (has_min_version(3)) {
return namespace_;
}
return &g_default_namespace;
}
ElfW(Addr) soinfo::resolve_symbol_address(const ElfW(Sym)* s) const {
if (ELF_ST_TYPE(s->st_info) == STT_GNU_IFUNC) {
return call_ifunc_resolver(s->st_value + load_bias);
@@ -3464,7 +3751,8 @@ static soinfo* linker_soinfo_for_gdb = nullptr;
* be on the soinfo list.
*/
static void init_linker_info_for_gdb(ElfW(Addr) linker_base) {
linker_soinfo_for_gdb = new (linker_soinfo_for_gdb_buf) soinfo(LINKER_PATH, nullptr, 0, 0);
linker_soinfo_for_gdb = new (linker_soinfo_for_gdb_buf) soinfo(nullptr, LINKER_PATH,
nullptr, 0, 0);
linker_soinfo_for_gdb->load_bias = linker_base;
@@ -3481,14 +3769,25 @@ static void init_linker_info_for_gdb(ElfW(Addr) linker_base) {
insert_soinfo_into_debug_map(linker_soinfo_for_gdb);
}
static void init_default_ld_library_path() {
static void init_default_namespace() {
g_default_namespace.set_name("(default)");
g_default_namespace.set_isolated(false);
const char *interp = phdr_table_get_interpreter_name(somain->phdr, somain->phnum,
somain->load_bias);
const char* bname = basename(interp);
if (bname && (strcmp(bname, "linker_asan") == 0 || strcmp(bname, "linker_asan64") == 0))
if (bname && (strcmp(bname, "linker_asan") == 0 || strcmp(bname, "linker_asan64") == 0)) {
g_default_ld_paths = kAsanDefaultLdPaths;
else
} else {
g_default_ld_paths = kDefaultLdPaths;
}
std::vector<std::string> ld_default_paths;
for (size_t i = 0; g_default_ld_paths[i] != nullptr; ++i) {
ld_default_paths.push_back(g_default_ld_paths[i]);
}
g_default_namespace.set_default_library_paths(std::move(ld_default_paths));
};
extern "C" int __system_properties_init(void);
@@ -3529,7 +3828,7 @@ static ElfW(Addr) __linker_init_post_relocation(KernelArgumentBlock& args, ElfW(
INFO("[ android linker & debugger ]");
soinfo* si = soinfo_alloc(args.argv[0], nullptr, 0, RTLD_GLOBAL);
soinfo* si = soinfo_alloc(&g_default_namespace, args.argv[0], nullptr, 0, RTLD_GLOBAL);
if (si == nullptr) {
exit(EXIT_FAILURE);
}
@@ -3581,11 +3880,10 @@ static ElfW(Addr) __linker_init_post_relocation(KernelArgumentBlock& args, ElfW(
somain = si;
init_default_ld_library_path();
init_default_namespace();
if (!si->prelink_image()) {
__libc_format_fd(2, "CANNOT LINK EXECUTABLE: %s\n", linker_get_error_buffer());
exit(EXIT_FAILURE);
__libc_fatal("CANNOT LINK EXECUTABLE: %s", linker_get_error_buffer());
}
// add somain to global group
@@ -3613,15 +3911,13 @@ static ElfW(Addr) __linker_init_post_relocation(KernelArgumentBlock& args, ElfW(
needed_library_name_list.copy_to_array(needed_library_names, needed_libraries_count);
if (needed_libraries_count > 0 &&
!find_libraries(si, needed_library_names, needed_libraries_count, nullptr,
&g_ld_preloads, ld_preloads_count, RTLD_GLOBAL, nullptr,
!find_libraries(&g_default_namespace, si, needed_library_names, needed_libraries_count,
nullptr, &g_ld_preloads, ld_preloads_count, RTLD_GLOBAL, nullptr,
/* add_as_children */ true)) {
__libc_format_fd(2, "CANNOT LINK EXECUTABLE: %s\n", linker_get_error_buffer());
exit(EXIT_FAILURE);
__libc_fatal("CANNOT LINK EXECUTABLE: %s", linker_get_error_buffer());
} else if (needed_libraries_count == 0) {
if (!si->link_image(g_empty_list, soinfo::soinfo_list_t::make_list(si), nullptr)) {
__libc_format_fd(2, "CANNOT LINK EXECUTABLE: %s\n", linker_get_error_buffer());
exit(EXIT_FAILURE);
__libc_fatal("CANNOT LINK EXECUTABLE: %s", linker_get_error_buffer());
}
si->increment_ref_count();
}
@@ -3730,7 +4026,7 @@ extern "C" ElfW(Addr) __linker_init(void* raw_args) {
ElfW(Ehdr)* elf_hdr = reinterpret_cast<ElfW(Ehdr)*>(linker_addr);
ElfW(Phdr)* phdr = reinterpret_cast<ElfW(Phdr)*>(linker_addr + elf_hdr->e_phoff);
soinfo linker_so(nullptr, nullptr, 0, 0);
soinfo linker_so(nullptr, nullptr, nullptr, 0, 0);
// If the linker is not acting as PT_INTERP entry_point is equal to
// _start. Which means that the linker is running as an executable and
@@ -3739,7 +4035,7 @@ extern "C" ElfW(Addr) __linker_init(void* raw_args) {
// This happens when user tries to run 'adb shell /system/bin/linker'
// see also https://code.google.com/p/android/issues/detail?id=63174
if (reinterpret_cast<ElfW(Addr)>(&_start) == entry_point) {
__libc_fatal("This is %s, the helper program for shared library executables.\n", args.argv[0]);
__libc_fatal("This is %s, the helper program for shared library executables.", args.argv[0]);
}
linker_so.base = linker_addr;
@@ -3757,15 +4053,7 @@ extern "C" ElfW(Addr) __linker_init(void* raw_args) {
// are not yet initialized, and therefore we cannot use linked_list.push_*
// functions at this point.
if (!(linker_so.prelink_image() && linker_so.link_image(g_empty_list, g_empty_list, nullptr))) {
// It would be nice to print an error message, but if the linker
// can't link itself, there's no guarantee that we'll be able to
// call write() (because it involves a GOT reference). We may as
// well try though...
const char* msg = "CANNOT LINK EXECUTABLE: ";
write(2, msg, strlen(msg));
write(2, __linker_dl_err_buf, strlen(__linker_dl_err_buf));
write(2, "\n", 1);
_exit(EXIT_FAILURE);
__libc_fatal("CANNOT LINK EXECUTABLE: %s", linker_get_error_buffer());
}
__libc_init_main_thread(args);
@@ -3781,6 +4069,7 @@ extern "C" ElfW(Addr) __linker_init(void* raw_args) {
// before get_libdl_info().
solist = get_libdl_info();
sonext = get_libdl_info();
g_default_namespace.soinfo_list().push_back(get_libdl_info());
// We have successfully fixed our own relocations. It's safe to run
// the main part of the linker now.