/*
* Copyright (C) 2016 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "linker_main.h"
#include <link.h>
#include <sys/auxv.h>
#include "linker_debug.h"
#include "linker_cfi.h"
#include "linker_gdb_support.h"
#include "linker_globals.h"
#include "linker_phdr.h"
#include "linker_tls.h"
#include "linker_utils.h"
#include "private/bionic_globals.h"
#include "private/bionic_tls.h"
#include "private/KernelArgumentBlock.h"
#include "android-base/unique_fd.h"
#include "android-base/strings.h"
#include "android-base/stringprintf.h"
#ifdef __ANDROID__
#include "debuggerd/handler.h"
#endif
#include <async_safe/log.h>
#include <bionic/libc_init_common.h>
#include <bionic/pthread_internal.h>
#include <vector>
__LIBC_HIDDEN__ extern "C" void _start();
static ElfW(Addr) get_elf_exec_load_bias(const ElfW(Ehdr)* elf);
static void get_elf_base_from_phdr(const ElfW(Phdr)* phdr_table, size_t phdr_count,
ElfW(Addr)* base, ElfW(Addr)* load_bias);
// These should be preserved static to avoid emitting
// RELATIVE relocations for the part of the code running
// before linker links itself.
// TODO (dimtiry): remove somain, rename solist to solist_head
static soinfo* solist;
static soinfo* sonext;
static soinfo* somain; // main process, always the one after libdl_info
static soinfo* solinker;
static soinfo* vdso; // vdso if present
void solist_add_soinfo(soinfo* si) {
sonext->next = si;
sonext = si;
}
bool solist_remove_soinfo(soinfo* si) {
soinfo *prev = nullptr, *trav;
for (trav = solist; trav != nullptr; trav = trav->next) {
if (trav == si) {
break;
}
prev = trav;
}
if (trav == nullptr) {
// si was not in solist
PRINT("name \"%s\"@%p is not in solist!", si->get_realpath(), si);
return false;
}
// prev will never be null, because the first entry in solist is
// always the static libdl_info.
CHECK(prev != nullptr);
prev->next = si->next;
if (si == sonext) {
sonext = prev;
}
return true;
}
soinfo* solist_get_head() {
return solist;
}
soinfo* solist_get_somain() {
return somain;
}
soinfo* solist_get_vdso() {
return vdso;
}
int g_ld_debug_verbosity;
static std::vector<std::string> g_ld_preload_names;
static std::vector<soinfo*> g_ld_preloads;
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) {
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));
}
static void parse_LD_PRELOAD(const char* path) {
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, " :");
g_ld_preload_names.erase(std::remove_if(g_ld_preload_names.begin(), g_ld_preload_names.end(),
[](const std::string& s) { return s.empty(); }),
g_ld_preload_names.end());
}
}
// An empty list of soinfos
static soinfo_list_t g_empty_list;
static void add_vdso() {
ElfW(Ehdr)* ehdr_vdso = reinterpret_cast<ElfW(Ehdr)*>(getauxval(AT_SYSINFO_EHDR));
if (ehdr_vdso == nullptr) {
return;
}
soinfo* si = soinfo_alloc(&g_default_namespace, "[vdso]", nullptr, 0, 0);
si->phdr = reinterpret_cast<ElfW(Phdr)*>(reinterpret_cast<char*>(ehdr_vdso) + ehdr_vdso->e_phoff);
si->phnum = ehdr_vdso->e_phnum;
si->base = reinterpret_cast<ElfW(Addr)>(ehdr_vdso);
si->size = phdr_table_get_load_size(si->phdr, si->phnum);
si->load_bias = get_elf_exec_load_bias(ehdr_vdso);
si->prelink_image();
si->link_image(g_empty_list, soinfo_list_t::make_list(si), nullptr, nullptr);
// prevents accidental unloads...
si->set_dt_flags_1(si->get_dt_flags_1() | DF_1_NODELETE);
si->set_linked();
si->call_constructors();
vdso = si;
}
// Initializes an soinfo's link_map_head field using other fields from the
// soinfo (phdr, phnum, load_bias).
static void init_link_map_head(soinfo& info, const char* linker_path) {
auto& map = info.link_map_head;
map.l_addr = info.load_bias;
map.l_name = const_cast<char*>(linker_path);
phdr_table_get_dynamic_section(info.phdr, info.phnum, info.load_bias, &map.l_ld, nullptr);
}
extern "C" int __system_properties_init(void);
struct ExecutableInfo {
std::string path;
struct stat file_stat;
const ElfW(Phdr)* phdr;
size_t phdr_count;
ElfW(Addr) entry_point;
};
static ExecutableInfo get_executable_info() {
ExecutableInfo result = {};
if (is_first_stage_init()) {
// /proc fs is not mounted when first stage init starts. Therefore we can't
// use /proc/self/exe for init.
stat("/init", &result.file_stat);
// /init may be a symlink, so try to read it as such.
char path[PATH_MAX];
ssize_t path_len = readlink("/init", path, sizeof(path));
if (path_len == -1 || path_len >= static_cast<ssize_t>(sizeof(path))) {
result.path = "/init";
} else {
result.path = std::string(path, path_len);
}
} else {
// Stat "/proc/self/exe" instead of executable_path because
// the executable could be unlinked by this point and it should
// not cause a crash (see http://b/31084669)
if (TEMP_FAILURE_RETRY(stat("/proc/self/exe", &result.file_stat)) != 0) {
async_safe_fatal("unable to stat \"/proc/self/exe\": %s", strerror(errno));
}
char path[PATH_MAX];
ssize_t path_len = readlink("/proc/self/exe", path, sizeof(path));
if (path_len == -1 || path_len >= static_cast<ssize_t>(sizeof(path))) {
async_safe_fatal("readlink('/proc/self/exe') failed: %s", strerror(errno));
}
result.path = std::string(path, path_len);
}
result.phdr = reinterpret_cast<const ElfW(Phdr)*>(getauxval(AT_PHDR));
result.phdr_count = getauxval(AT_PHNUM);
result.entry_point = getauxval(AT_ENTRY);
return result;
}
#if defined(__LP64__)
static char kLinkerPath[] = "/system/bin/linker64";
#else
static char kLinkerPath[] = "/system/bin/linker";
#endif
__printflike(1, 2)
static void __linker_error(const char* fmt, ...) {
va_list ap;
va_start(ap, fmt);
async_safe_format_fd_va_list(STDERR_FILENO, fmt, ap);
va_end(ap);
va_start(ap, fmt);
async_safe_format_log_va_list(ANDROID_LOG_FATAL, "linker", fmt, ap);
va_end(ap);
_exit(EXIT_FAILURE);
}
static void __linker_cannot_link(const char* argv0) {
__linker_error("CANNOT LINK EXECUTABLE \"%s\": %s\n",
argv0,
linker_get_error_buffer());
}
// Load an executable. Normally the kernel has already loaded the executable when the linker
// starts. The linker can be invoked directly on an executable, though, and then the linker must
// load it. This function doesn't load dependencies or resolve relocations.
static ExecutableInfo load_executable(const char* orig_path) {
ExecutableInfo result = {};
if (orig_path[0] != '/') {
__linker_error("error: expected absolute path: \"%s\"\n", orig_path);
}
off64_t file_offset;
android::base::unique_fd fd(open_executable(orig_path, &file_offset, &result.path));
if (fd.get() == -1) {
__linker_error("error: unable to open file \"%s\"\n", orig_path);
}
if (TEMP_FAILURE_RETRY(fstat(fd.get(), &result.file_stat)) == -1) {
__linker_error("error: unable to stat \"%s\": %s\n", result.path.c_str(), strerror(errno));
}
ElfReader elf_reader;
if (!elf_reader.Read(result.path.c_str(), fd.get(), file_offset, result.file_stat.st_size)) {
__linker_error("error: %s\n", linker_get_error_buffer());
}
address_space_params address_space;
if (!elf_reader.Load(&address_space)) {
__linker_error("error: %s\n", linker_get_error_buffer());
}
result.phdr = elf_reader.loaded_phdr();
result.phdr_count = elf_reader.phdr_count();
result.entry_point = elf_reader.entry_point();
return result;
}
static ElfW(Addr) linker_main(KernelArgumentBlock& args, const char* exe_to_load) {
ProtectedDataGuard guard;
#if TIMING
struct timeval t0, t1;
gettimeofday(&t0, 0);
#endif
// Sanitize the environment.
__libc_init_AT_SECURE(args.envp);
// Initialize system properties
__system_properties_init(); // may use 'environ'
// Register the debuggerd signal handler.
#ifdef __ANDROID__
debuggerd_callbacks_t callbacks = {
.get_abort_message = []() {
return __libc_shared_globals()->abort_msg;
},
.post_dump = ¬ify_gdb_of_libraries,
};
debuggerd_init(&callbacks);
#endif
g_linker_logger.ResetState();
// Get a few environment variables.
const char* LD_DEBUG = getenv("LD_DEBUG");
if (LD_DEBUG != nullptr) {
g_ld_debug_verbosity = atoi(LD_DEBUG);
}
#if defined(__LP64__)
INFO("[ Android dynamic linker (64-bit) ]");
#else
INFO("[ Android dynamic linker (32-bit) ]");
#endif
// These should have been sanitized by __libc_init_AT_SECURE, but the test
// doesn't cost us anything.
const char* ldpath_env = nullptr;
const char* ldpreload_env = nullptr;
if (!getauxval(AT_SECURE)) {
ldpath_env = getenv("LD_LIBRARY_PATH");
if (ldpath_env != nullptr) {
INFO("[ LD_LIBRARY_PATH set to \"%s\" ]", ldpath_env);
}
ldpreload_env = getenv("LD_PRELOAD");
if (ldpreload_env != nullptr) {
INFO("[ LD_PRELOAD set to \"%s\" ]", ldpreload_env);
}
}
const ExecutableInfo exe_info = exe_to_load ? load_executable(exe_to_load) :
get_executable_info();
// Assign to a static variable for the sake of the debug map, which needs
// a C-style string to last until the program exits.
static std::string exe_path = exe_info.path;
INFO("[ Linking executable \"%s\" ]", exe_path.c_str());
// Initialize the main exe's soinfo.
soinfo* si = soinfo_alloc(&g_default_namespace,
exe_path.c_str(), &exe_info.file_stat,
0, RTLD_GLOBAL);
somain = si;
si->phdr = exe_info.phdr;
si->phnum = exe_info.phdr_count;
get_elf_base_from_phdr(si->phdr, si->phnum, &si->base, &si->load_bias);
si->size = phdr_table_get_load_size(si->phdr, si->phnum);
si->dynamic = nullptr;
si->set_main_executable();
init_link_map_head(*si, exe_path.c_str());
// Register the main executable and the linker upfront to have
// gdb aware of them before loading the rest of the dependency
// tree.
//
// gdb expects the linker to be in the debug shared object list.
// Without this, gdb has trouble locating the linker's ".text"
// and ".plt" sections. Gdb could also potentially use this to
// relocate the offset of our exported 'rtld_db_dlactivity' symbol.
//
insert_link_map_into_debug_map(&si->link_map_head);
insert_link_map_into_debug_map(&solinker->link_map_head);
add_vdso();
ElfW(Ehdr)* elf_hdr = reinterpret_cast<ElfW(Ehdr)*>(si->base);
// We haven't supported non-PIE since Lollipop for security reasons.
if (elf_hdr->e_type != ET_DYN) {
// We don't use async_safe_fatal here because we don't want a tombstone:
// even after several years we still find ourselves on app compatibility
// investigations because some app's trying to launch an executable that
// hasn't worked in at least three years, and we've "helpfully" dropped a
// tombstone for them. The tombstone never provided any detail relevant to
// fixing the problem anyway, and the utility of drawing extra attention
// to the problem is non-existent at this late date.
async_safe_format_fd(STDERR_FILENO,
"\"%s\": error: Android 5.0 and later only support "
"position-independent executables (-fPIE).\n",
g_argv[0]);
exit(EXIT_FAILURE);
}
// Use LD_LIBRARY_PATH and LD_PRELOAD (but only if we aren't setuid/setgid).
parse_LD_LIBRARY_PATH(ldpath_env);
parse_LD_PRELOAD(ldpreload_env);
std::vector<android_namespace_t*> namespaces = init_default_namespaces(exe_path.c_str());
if (!si->prelink_image()) __linker_cannot_link(g_argv[0]);
// add somain to global group
si->set_dt_flags_1(si->get_dt_flags_1() | DF_1_GLOBAL);
// ... and add it to all other linked namespaces
for (auto linked_ns : namespaces) {
if (linked_ns != &g_default_namespace) {
linked_ns->add_soinfo(somain);
somain->add_secondary_namespace(linked_ns);
}
}
linker_setup_exe_static_tls(g_argv[0]);
// Load ld_preloads and dependencies.
std::vector<const char*> needed_library_name_list;
size_t ld_preloads_count = 0;
for (const auto& ld_preload_name : g_ld_preload_names) {
needed_library_name_list.push_back(ld_preload_name.c_str());
++ld_preloads_count;
}
for_each_dt_needed(si, [&](const char* name) {
needed_library_name_list.push_back(name);
});
const char** needed_library_names = &needed_library_name_list[0];
size_t needed_libraries_count = needed_library_name_list.size();
if (needed_libraries_count > 0 &&
!find_libraries(&g_default_namespace,
si,
needed_library_names,
needed_libraries_count,
nullptr,
&g_ld_preloads,
ld_preloads_count,
RTLD_GLOBAL,
nullptr,
true /* add_as_children */,
true /* search_linked_namespaces */,
&namespaces)) {
__linker_cannot_link(g_argv[0]);
} else if (needed_libraries_count == 0) {
if (!si->link_image(g_empty_list, soinfo_list_t::make_list(si), nullptr, nullptr)) {
__linker_cannot_link(g_argv[0]);
}
si->increment_ref_count();
}
linker_finalize_static_tls();
__libc_init_main_thread_final();
if (!get_cfi_shadow()->InitialLinkDone(solist)) __linker_cannot_link(g_argv[0]);
si->call_pre_init_constructors();
si->call_constructors();
#if TIMING
gettimeofday(&t1, nullptr);
PRINT("LINKER TIME: %s: %d microseconds", g_argv[0], (int) (
(((long long)t1.tv_sec * 1000000LL) + (long long)t1.tv_usec) -
(((long long)t0.tv_sec * 1000000LL) + (long long)t0.tv_usec)));
#endif
#if STATS
PRINT("RELO STATS: %s: %d abs, %d rel, %d copy, %d symbol", g_argv[0],
linker_stats.count[kRelocAbsolute],
linker_stats.count[kRelocRelative],
linker_stats.count[kRelocCopy],
linker_stats.count[kRelocSymbol]);
#endif
#if COUNT_PAGES
{
unsigned n;
unsigned i;
unsigned count = 0;
for (n = 0; n < 4096; n++) {
if (bitmask[n]) {
unsigned x = bitmask[n];
#if defined(__LP64__)
for (i = 0; i < 32; i++) {
#else
for (i = 0; i < 8; i++) {
#endif
if (x & 1) {
count++;
}
x >>= 1;
}
}
}
PRINT("PAGES MODIFIED: %s: %d (%dKB)", g_argv[0], count, count * 4);
}
#endif
#if TIMING || STATS || COUNT_PAGES
fflush(stdout);
#endif
// We are about to hand control over to the executable loaded. We don't want
// to leave dirty pages behind unnecessarily.
purge_unused_memory();
ElfW(Addr) entry = exe_info.entry_point;
TRACE("[ Ready to execute \"%s\" @ %p ]", si->get_realpath(), reinterpret_cast<void*>(entry));
return entry;
}
/* Compute the load-bias of an existing executable. This shall only
* be used to compute the load bias of an executable or shared library
* that was loaded by the kernel itself.
*
* Input:
* elf -> address of ELF header, assumed to be at the start of the file.
* Return:
* load bias, i.e. add the value of any p_vaddr in the file to get
* the corresponding address in memory.
*/
static ElfW(Addr) get_elf_exec_load_bias(const ElfW(Ehdr)* elf) {
ElfW(Addr) offset = elf->e_phoff;
const ElfW(Phdr)* phdr_table =
reinterpret_cast<const ElfW(Phdr)*>(reinterpret_cast<uintptr_t>(elf) + offset);
const ElfW(Phdr)* phdr_end = phdr_table + elf->e_phnum;
for (const ElfW(Phdr)* phdr = phdr_table; phdr < phdr_end; phdr++) {
if (phdr->p_type == PT_LOAD) {
return reinterpret_cast<ElfW(Addr)>(elf) + phdr->p_offset - phdr->p_vaddr;
}
}
return 0;
}
/* Find the load bias and base address of an executable or shared object loaded
* by the kernel. The ELF file's PHDR table must have a PT_PHDR entry.
*
* A VDSO doesn't have a PT_PHDR entry in its PHDR table.
*/
static void get_elf_base_from_phdr(const ElfW(Phdr)* phdr_table, size_t phdr_count,
ElfW(Addr)* base, ElfW(Addr)* load_bias) {
for (size_t i = 0; i < phdr_count; ++i) {
if (phdr_table[i].p_type == PT_PHDR) {
*load_bias = reinterpret_cast<ElfW(Addr)>(phdr_table) - phdr_table[i].p_vaddr;
*base = reinterpret_cast<ElfW(Addr)>(phdr_table) - phdr_table[i].p_offset;
return;
}
}
async_safe_fatal("Could not find a PHDR: broken executable?");
}
// Detect an attempt to run the linker on itself. e.g.:
// /system/bin/linker64 /system/bin/linker64
// Use priority-1 to run this constructor before other constructors.
__attribute__((constructor(1))) static void detect_self_exec() {
// Normally, the linker initializes the auxv global before calling its
// constructors. If the linker loads itself, though, the first loader calls
// the second loader's constructors before calling __linker_init.
if (__libc_shared_globals()->auxv != nullptr) {
return;
}
#if defined(__i386__)
// We don't have access to the auxv struct from here, so use the int 0x80
// fallback.
__libc_sysinfo = reinterpret_cast<void*>(__libc_int0x80);
#endif
__linker_error("error: linker cannot load itself\n");
}
static ElfW(Addr) __attribute__((noinline))
__linker_init_post_relocation(KernelArgumentBlock& args, soinfo& linker_so);
/*
* This is the entry point for the linker, called from begin.S. This
* method is responsible for fixing the linker's own relocations, and
* then calling __linker_init_post_relocation().
*
* Because this method is called before the linker has fixed it's own
* relocations, any attempt to reference an extern variable, extern
* function, or other GOT reference will generate a segfault.
*/
extern "C" ElfW(Addr) __linker_init(void* raw_args) {
// Initialize TLS early so system calls and errno work.
KernelArgumentBlock args(raw_args);
bionic_tcb temp_tcb = {};
__libc_init_main_thread_early(args, &temp_tcb);
// When the linker is run by itself (rather than as an interpreter for
// another program), AT_BASE is 0.
ElfW(Addr) linker_addr = getauxval(AT_BASE);
if (linker_addr == 0) {
// The AT_PHDR and AT_PHNUM aux values describe this linker instance, so use
// the phdr to find the linker's base address.
ElfW(Addr) load_bias;
get_elf_base_from_phdr(
reinterpret_cast<ElfW(Phdr)*>(getauxval(AT_PHDR)), getauxval(AT_PHNUM),
&linker_addr, &load_bias);
}
ElfW(Ehdr)* elf_hdr = reinterpret_cast<ElfW(Ehdr)*>(linker_addr);
ElfW(Phdr)* phdr = reinterpret_cast<ElfW(Phdr)*>(linker_addr + elf_hdr->e_phoff);
soinfo tmp_linker_so(nullptr, nullptr, nullptr, 0, 0);
tmp_linker_so.base = linker_addr;
tmp_linker_so.size = phdr_table_get_load_size(phdr, elf_hdr->e_phnum);
tmp_linker_so.load_bias = get_elf_exec_load_bias(elf_hdr);
tmp_linker_so.dynamic = nullptr;
tmp_linker_so.phdr = phdr;
tmp_linker_so.phnum = elf_hdr->e_phnum;
tmp_linker_so.set_linker_flag();
// Prelink the linker so we can access linker globals.
if (!tmp_linker_so.prelink_image()) __linker_cannot_link(args.argv[0]);
// This might not be obvious... The reasons why we pass g_empty_list
// in place of local_group here are (1) we do not really need it, because
// linker is built with DT_SYMBOLIC and therefore relocates its symbols against
// itself without having to look into local_group and (2) allocators
// are not yet initialized, and therefore we cannot use linked_list.push_*
// functions at this point.
if (!tmp_linker_so.link_image(g_empty_list, g_empty_list, nullptr, nullptr)) __linker_cannot_link(args.argv[0]);
return __linker_init_post_relocation(args, tmp_linker_so);
}
/*
* This code is called after the linker has linked itself and fixed its own
* GOT. It is safe to make references to externs and other non-local data at
* this point. The compiler sometimes moves GOT references earlier in a
* function, so avoid inlining this function (http://b/80503879).
*/
static ElfW(Addr) __attribute__((noinline))
__linker_init_post_relocation(KernelArgumentBlock& args, soinfo& tmp_linker_so) {
// Finish initializing the main thread.
__libc_init_main_thread_late();
// We didn't protect the linker's RELRO pages in link_image because we
// couldn't make system calls on x86 at that point, but we can now...
if (!tmp_linker_so.protect_relro()) __linker_cannot_link(args.argv[0]);
// Initialize the linker's static libc's globals
__libc_init_globals();
// Initialize the linker's own global variables
tmp_linker_so.call_constructors();
// When the linker is run directly rather than acting as PT_INTERP, parse
// arguments and determine the executable to load. When it's instead acting
// as PT_INTERP, AT_ENTRY will refer to the loaded executable rather than the
// linker's _start.
const char* exe_to_load = nullptr;
if (getauxval(AT_ENTRY) == reinterpret_cast<uintptr_t>(&_start)) {
if (args.argc <= 1 || !strcmp(args.argv[1], "--help")) {
async_safe_format_fd(STDOUT_FILENO,
"Usage: %s program [arguments...]\n"
" %s path.zip!/program [arguments...]\n"
"\n"
"A helper program for linking dynamic executables. Typically, the kernel loads\n"
"this program because it's the PT_INTERP of a dynamic executable.\n"
"\n"
"This program can also be run directly to load and run a dynamic executable. The\n"
"executable can be inside a zip file if it's stored uncompressed and at a\n"
"page-aligned offset.\n",
args.argv[0], args.argv[0]);
exit(0);
}
exe_to_load = args.argv[1];
__libc_shared_globals()->initial_linker_arg_count = 1;
}
// store argc/argv/envp to use them for calling constructors
g_argc = args.argc - __libc_shared_globals()->initial_linker_arg_count;
g_argv = args.argv + __libc_shared_globals()->initial_linker_arg_count;
g_envp = args.envp;
__libc_shared_globals()->init_progname = g_argv[0];
// Initialize static variables. Note that in order to
// get correct libdl_info we need to call constructors
// before get_libdl_info().
sonext = solist = solinker = get_libdl_info(kLinkerPath, tmp_linker_so);
g_default_namespace.add_soinfo(solinker);
init_link_map_head(*solinker, kLinkerPath);
ElfW(Addr) start_address = linker_main(args, exe_to_load);
INFO("[ Jumping to _start (%p)... ]", reinterpret_cast<void*>(start_address));
// Return the address that the calling assembly stub should jump to.
return start_address;
}