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chromium / arc / arc / a9f332c4640c050f8c5b45d86e7b6c6467bb835e / . / mods / android / bionic / linker / linker.cpp
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/*
* Copyright (C) 2008, 2009 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 <dlfcn.h>
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <unistd.h>
// Private C library headers.
#include "private/bionic_tls.h"
#include "private/KernelArgumentBlock.h"
#include "private/ScopedPthreadMutexLocker.h"
#include "private/ScopedFd.h"
// ARC MOD BEGIN
// Add includes.
#if defined(HAVE_ARC)
#include <irt_syscalls.h>
#include <nacl_dyncode.h>
#include <private/at_sysinfo.h>
#include <private/dl_dst_lib.h>
#include <private/inject_arc_linker_hooks.h>
#include <private/irt_query_marker.h>
// TODO(crbug.com/354290): Remove this include. This is only for GDB hack.
#if defined(BARE_METAL_BIONIC)
#include <sys/syscall.h>
#endif
// TODO(crbug.com/465216): Remove Bare Metal i686 from this #if.
#if ((defined(BARE_METAL_BIONIC) && defined(__i386__)) || \
(defined(__native_client__) && defined(__x86_64__)))
#include <private/get_tls_for_art.h>
#endif
#endif
// ARC MOD END
#include "linker.h"
#include "linker_debug.h"
#include "linker_environ.h"
#include "linker_phdr.h"
// ARC MOD BEGIN
// Add a function prototype.
#if defined(__native_client__)
void phdr_table_get_nacl_gapped_layout_info(
const ElfW(Phdr)* phdr_table,
size_t phdr_count,
size_t* code_first,
size_t* code_size,
size_t* data_first,
size_t* data_size);
// These symbols are provided by a modified linker script.
// See out/target/nacl_*/runnable-ld.lds generated from
// bionic/linker/arch/nacl/gen_runnable_ld_lds.py.
// __init_array is a symbol that points the start of .init_array section.
// __init_array_end points the end of .init_array section. They are used to
// calculate soinfo.init_array and soinfo.init_array_count to call
// CallConstructors().
extern linker_function_t __init_array;
extern linker_function_t __init_array_end;
#endif // __native_client__
// Add the forward declaration for load_main_binary.
#if defined(HAVE_ARC)
static soinfo* load_main_binary(KernelArgumentBlock& args);
#endif
static void* (*g_resolve_symbol)(const char* symbol);
static int (*g_is_statically_linked)(const char* filename);
// TODO(crbug.com/364344): Remove /vendor/lib.
const char kVendorLibDir[] = "/vendor/lib/";
// ARC MOD END
#include "linker_allocator.h"
/* >>> IMPORTANT NOTE - READ ME BEFORE MODIFYING <<<
*
* Do NOT use malloc() and friends or pthread_*() code here.
* Don't use printf() either; it's caused mysterious memory
* corruption in the past.
* The linker runs before we bring up libc and it's easiest
* to make sure it does not depend on any complex libc features
*
* open issues / todo:
*
* - cleaner error reporting
* - after linking, set as much stuff as possible to READONLY
* and NOEXEC
*/
// ARC MOD BEGIN
// For showing some performance stats when --logging=bionic-loader is
// specified.
#if defined(BIONIC_LOADER_LOGGING)
template <int line_number>
class ScopedElapsedTimePrinter {
public:
ScopedElapsedTimePrinter(const char* category, const char* name)
: category_(category), name_(name) {
gettimeofday(&t0_, NULL);
}
~ScopedElapsedTimePrinter() {
timeval t1;
gettimeofday(&t1, NULL);
const int elapsed =
(((long long)t1.tv_sec * 1000000LL) + (long long)t1.tv_usec) -
(((long long)t0_.tv_sec * 1000000LL) + (long long)t0_.tv_usec);
cumulative_ += elapsed;
PRINT("LINKER TIME: %s %s: %d us (%d ms cumulative for line:%d)",
category_, name_, elapsed, cumulative_ / 1000, line_number);
}
private:
static int cumulative_; // held per |line_number|
const char* category_;
const char* name_;
timeval t0_;
};
template <int line_number>
int ScopedElapsedTimePrinter<line_number>::cumulative_ = 0;
#else // BIONIC_LOADER_LOGGING
template <int line_number>
class ScopedElapsedTimePrinter {
public:
ScopedElapsedTimePrinter(const char* category, const char* name) {}
};
#endif // BIONIC_LOADER_LOGGING
// ARC MOD END
#if defined(__LP64__)
#define SEARCH_NAME(x) x
#else
// Nvidia drivers are relying on the bug:
// http://code.google.com/p/android/issues/detail?id=6670
// so we continue to use base-name lookup for lp32
static const char* get_base_name(const char* name) {
const char* bname = strrchr(name, '/');
return bname ? bname + 1 : name;
}
#define SEARCH_NAME(x) get_base_name(x)
#endif
static bool soinfo_link_image(soinfo* si, const android_dlextinfo* extinfo);
static ElfW(Addr) get_elf_exec_load_bias(const ElfW(Ehdr)* elf);
static LinkerAllocator<soinfo> g_soinfo_allocator;
static LinkerAllocator<LinkedListEntry<soinfo>> g_soinfo_links_allocator;
static soinfo* solist;
static soinfo* sonext;
static soinfo* somain; /* main process, always the one after libdl_info */
static const char* const kDefaultLdPaths[] = {
#if defined(__LP64__)
"/vendor/lib64",
"/system/lib64",
#else
"/vendor/lib",
"/system/lib",
#endif
NULL
};
#define LDPATH_BUFSIZE (LDPATH_MAX*64)
#define LDPATH_MAX 8
#define LDPRELOAD_BUFSIZE (LDPRELOAD_MAX*64)
#define LDPRELOAD_MAX 8
static char g_ld_library_paths_buffer[LDPATH_BUFSIZE];
static const char* g_ld_library_paths[LDPATH_MAX + 1];
static char g_ld_preloads_buffer[LDPRELOAD_BUFSIZE];
static const char* g_ld_preload_names[LDPRELOAD_MAX + 1];
static soinfo* g_ld_preloads[LDPRELOAD_MAX + 1];
// ARC MOD BEGIN
// When you port the linker MODs to a newer Bionic release, you might want
// to initialize |g_ld_debug_verbosity| with 3 to get full debug logs (such as
// DL_ERR) from the linker. As neither sel_ldr nor nacl_helper
// propagates environment variables, you need to modify this parameter
// directly. Note that this value will be updated to -1 in
// __linker_init for --disable-debug-code build.
//
// run_unittest.py --gdb is also useful to debug crashes when porting
// the linker:
// $ ninja out/target/nacl_x86_64_dbg/bionic_tests/loader_test
// $ src/build/run_unittest.py bionic_fundamental_loader_test
// ARC MOD END
__LIBC_HIDDEN__ int g_ld_debug_verbosity;
__LIBC_HIDDEN__ abort_msg_t* g_abort_message = NULL; // For debuggerd.
enum RelocationKind {
kRelocAbsolute = 0,
kRelocRelative,
kRelocCopy,
kRelocSymbol,
kRelocMax
};
#if STATS
struct linker_stats_t {
int count[kRelocMax];
};
static linker_stats_t linker_stats;
static void count_relocation(RelocationKind kind) {
++linker_stats.count[kind];
}
#else
static void count_relocation(RelocationKind) {
}
#endif
#if COUNT_PAGES
static unsigned bitmask[4096];
#if defined(__LP64__)
#define MARK(offset) \
do { \
if ((((offset) >> 12) >> 5) < 4096) \
bitmask[((offset) >> 12) >> 5] |= (1 << (((offset) >> 12) & 31)); \
} while (0)
#else
#define MARK(offset) \
do { \
bitmask[((offset) >> 12) >> 3] |= (1 << (((offset) >> 12) & 7)); \
} while (0)
#endif
#else
#define MARK(x) do {} while (0)
#endif
// You shouldn't try to call memory-allocating functions in the dynamic linker.
// Guard against the most obvious ones.
#define DISALLOW_ALLOCATION(return_type, name, ...) \
return_type name __VA_ARGS__ \
{ \
__libc_fatal("ERROR: " #name " called from the dynamic linker!\n"); \
}
DISALLOW_ALLOCATION(void*, malloc, (size_t u __unused));
DISALLOW_ALLOCATION(void, free, (void* u __unused));
DISALLOW_ALLOCATION(void*, realloc, (void* u1 __unused, size_t u2 __unused));
DISALLOW_ALLOCATION(void*, calloc, (size_t u1 __unused, size_t u2 __unused));
static char tmp_err_buf[768];
static char __linker_dl_err_buf[768];
char* linker_get_error_buffer() {
return &__linker_dl_err_buf[0];
}
size_t linker_get_error_buffer_size() {
return sizeof(__linker_dl_err_buf);
}
/*
* This function is an empty stub where GDB locates a breakpoint to get notified
* about linker activity.
*/
extern "C" void __attribute__((noinline)) __attribute__((visibility("default"))) rtld_db_dlactivity();
static pthread_mutex_t g__r_debug_mutex = PTHREAD_MUTEX_INITIALIZER;
// ARC MOD BEGIN
// Cast rtld_db_dlactivity to Elf64_Addr on x86-64 NaCl.
#if defined(__native_client__) && defined(__x86_64__)
static r_debug _r_debug = {1, NULL, reinterpret_cast<Elf64_Addr>(&rtld_db_dlactivity),
r_debug::RT_CONSISTENT, 0};
#else
// ARC MOD END
static r_debug _r_debug = {1, NULL, reinterpret_cast<uintptr_t>(&rtld_db_dlactivity), r_debug::RT_CONSISTENT, 0};
// ARC MOD BEGIN
#endif
// ARC MOD END
static link_map* r_debug_tail = 0;
static void insert_soinfo_into_debug_map(soinfo* info) {
// Copy the necessary fields into the debug structure.
link_map* map = &(info->link_map_head);
// ARC MOD BEGIN
// TODO(crbug.com/465619): L-rebase: Verify if this new data is
// compatible with minidump. See also 'git show 914cd7f7'.
// ARC MOD END
map->l_addr = info->load_bias;
map->l_name = reinterpret_cast<char*>(info->name);
map->l_ld = info->dynamic;
/* Stick the new library at the end of the list.
* gdb tends to care more about libc than it does
* about leaf libraries, and ordering it this way
* reduces the back-and-forth over the wire.
*/
if (r_debug_tail) {
r_debug_tail->l_next = map;
map->l_prev = r_debug_tail;
map->l_next = 0;
} else {
_r_debug.r_map = map;
map->l_prev = 0;
map->l_next = 0;
}
r_debug_tail = map;
}
static void remove_soinfo_from_debug_map(soinfo* info) {
link_map* map = &(info->link_map_head);
if (r_debug_tail == map) {
r_debug_tail = map->l_prev;
}
if (map->l_prev) {
map->l_prev->l_next = map->l_next;
}
if (map->l_next) {
map->l_next->l_prev = map->l_prev;
}
}
// ARC MOD BEGIN
// See linker_notify.S.
#if defined(BARE_METAL_BIONIC)
extern "C"
void __bare_metal_notify_gdb_of_load(const char* name, ElfW(Addr) base);
#endif // BARE_METAL_BIONIC
// ARC MOD END
static void notify_gdb_of_load(soinfo* info) {
// ARC MOD BEGIN
// Always copy the necessary fields into the debug
// structure. The original Bionic loader fills these fields in
// insert_soinfo_into_debug_map, but we do not call this function
// for ET_EXEC or Bare Metal mode. The behavior of the original
// Bionic loader is OK because info->link_map is not used on normal
// Linux. The loader does not need to tell the information of the
// main binary to GDB.
// TODO(crbug.com/323864): Enable this on NaCl. Currently this is
// excluded to workaround the issue of minidumps not being generated.
#if defined(BARE_METAL_BIONIC)
link_map* map = &(info->link_map_head);
map->l_addr = info->base;
if (!map->l_name) {
// main binary's argv[0] is /lib/main.nexe, here it's main.nexe,
// keep /lib/main.nexe here. For shared libraries, it is NULL,
// so give it some value.
map->l_name = info->name;
}
map->l_ld = (ElfW(Dyn)*)info->dynamic;
__bare_metal_notify_gdb_of_load(info->name, info->base);
#else
// ARC MOD END
if (info->flags & FLAG_EXE) {
// GDB already knows about the main executable
return;
}
ScopedPthreadMutexLocker locker(&g__r_debug_mutex);
_r_debug.r_state = r_debug::RT_ADD;
rtld_db_dlactivity();
insert_soinfo_into_debug_map(info);
_r_debug.r_state = r_debug::RT_CONSISTENT;
rtld_db_dlactivity();
// ARC MOD BEGIN
#endif
// ARC MOD END
}
static void notify_gdb_of_unload(soinfo* info) {
// ARC MOD BEGIN
// Ask the Bare Metal loader to interact with GDB.
#if defined(BARE_METAL_BIONIC)
// We do not support notifying module unload to GDB yet.
#else
// ARC MOD END
if (info->flags & FLAG_EXE) {
// GDB already knows about the main executable
return;
}
ScopedPthreadMutexLocker locker(&g__r_debug_mutex);
_r_debug.r_state = r_debug::RT_DELETE;
rtld_db_dlactivity();
remove_soinfo_from_debug_map(info);
_r_debug.r_state = r_debug::RT_CONSISTENT;
rtld_db_dlactivity();
// ARC MOD BEGIN
#endif
// ARC MOD END
}
void notify_gdb_of_libraries() {
// ARC MOD BEGIN
// Ask the Bare Metal loader to interact with GDB.
#if defined(BARE_METAL_BIONIC)
// We do not support notifying all module updates to GDB yet.
#else
// ARC MOD END
_r_debug.r_state = r_debug::RT_ADD;
rtld_db_dlactivity();
_r_debug.r_state = r_debug::RT_CONSISTENT;
rtld_db_dlactivity();
// ARC MOD BEGIN
#endif
// ARC MOD END
}
LinkedListEntry<soinfo>* SoinfoListAllocator::alloc() {
return g_soinfo_links_allocator.alloc();
}
void SoinfoListAllocator::free(LinkedListEntry<soinfo>* entry) {
g_soinfo_links_allocator.free(entry);
}
static void protect_data(int protection) {
g_soinfo_allocator.protect_all(protection);
g_soinfo_links_allocator.protect_all(protection);
}
static soinfo* soinfo_alloc(const char* name, struct stat* file_stat) {
if (strlen(name) >= SOINFO_NAME_LEN) {
DL_ERR("library name \"%s\" too long", name);
return NULL;
}
soinfo* si = g_soinfo_allocator.alloc();
// Initialize the new element.
memset(si, 0, sizeof(soinfo));
strlcpy(si->name, name, sizeof(si->name));
si->flags = FLAG_NEW_SOINFO;
if (file_stat != NULL) {
si->set_st_dev(file_stat->st_dev);
si->set_st_ino(file_stat->st_ino);
}
sonext->next = si;
sonext = si;
TRACE("name %s: allocated soinfo @ %p", name, si);
return si;
}
static void soinfo_free(soinfo* si) {
if (si == NULL) {
return;
}
if (si->base != 0 && si->size != 0) {
// ARC MOD BEGIN
// When NaCl is in use, the linker maps text and data separately.
// The following code unmaps the latter.
#if defined(__native_client__)
size_t code_first = 0;
size_t code_size = 0;
size_t data_first = 0;
size_t data_size = 0;
phdr_table_get_nacl_gapped_layout_info(si->phdr,
si->phnum,
&code_first,
&code_size,
&data_first,
&data_size);
TRACE("soinfo_unload: munmap data: %p-%p\n",
(char *)data_first, (char *)data_first + data_size);
munmap((char *)data_first, data_size);
TRACE("soinfo_unload: munmap text: %p-%p\n",
(char *)si->base, (char *)si->base + si->size);
#else
TRACE("soinfo_unload: munmap: %p-%p\n",
(char *)si->base, (char *)si->base + si->size);
#endif
// ARC MOD END
munmap(reinterpret_cast<void*>(si->base), si->size);
}
soinfo *prev = NULL, *trav;
TRACE("name %s: freeing soinfo @ %p", si->name, si);
for (trav = solist; trav != NULL; trav = trav->next) {
if (trav == si)
break;
prev = trav;
}
if (trav == NULL) {
/* si was not in solist */
DL_ERR("name \"%s\" is not in solist!", si->name);
return;
}
// clear links to/from si
si->remove_all_links();
/* prev will never be NULL, because the first entry in solist is
always the static libdl_info.
*/
prev->next = si->next;
if (si == sonext) {
sonext = prev;
}
g_soinfo_allocator.free(si);
}
static void parse_path(const char* path, const char* delimiters,
const char** array, char* buf, size_t buf_size, size_t max_count) {
if (path == NULL) {
return;
}
size_t len = strlcpy(buf, path, buf_size);
size_t i = 0;
char* buf_p = buf;
while (i < max_count && (array[i] = strsep(&buf_p, delimiters))) {
if (*array[i] != '\0') {
++i;
}
}
// Forget the last path if we had to truncate; this occurs if the 2nd to
// last char isn't '\0' (i.e. wasn't originally a delimiter).
if (i > 0 && len >= buf_size && buf[buf_size - 2] != '\0') {
array[i - 1] = NULL;
} else {
array[i] = NULL;
}
}
static void parse_LD_LIBRARY_PATH(const char* path) {
parse_path(path, ":", g_ld_library_paths,
g_ld_library_paths_buffer, sizeof(g_ld_library_paths_buffer), LDPATH_MAX);
}
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_preloads_buffer, sizeof(g_ld_preloads_buffer), LDPRELOAD_MAX);
}
#if defined(__arm__)
/* For a given PC, find the .so that it belongs to.
* Returns the base address of the .ARM.exidx section
* for that .so, and the number of 8-byte entries
* in that section (via *pcount).
*
* Intended to be called by libc's __gnu_Unwind_Find_exidx().
*
* This function is exposed via dlfcn.cpp and libdl.so.
*/
_Unwind_Ptr dl_unwind_find_exidx(_Unwind_Ptr pc, int* pcount) {
unsigned addr = (unsigned)pc;
for (soinfo* si = solist; si != 0; si = si->next) {
if ((addr >= si->base) && (addr < (si->base + si->size))) {
*pcount = si->ARM_exidx_count;
return (_Unwind_Ptr)si->ARM_exidx;
}
}
*pcount = 0;
return NULL;
}
#endif
/* Here, we only have to provide a callback to iterate across all the
* loaded libraries. gcc_eh does the rest. */
int dl_iterate_phdr(int (*cb)(dl_phdr_info* info, size_t size, void* data), void* data) {
int rv = 0;
for (soinfo* si = solist; si != NULL; si = si->next) {
dl_phdr_info dl_info;
dl_info.dlpi_addr = si->link_map_head.l_addr;
dl_info.dlpi_name = si->link_map_head.l_name;
dl_info.dlpi_phdr = si->phdr;
dl_info.dlpi_phnum = si->phnum;
rv = cb(&dl_info, sizeof(dl_phdr_info), data);
if (rv != 0) {
break;
}
}
return rv;
}
static ElfW(Sym)* soinfo_elf_lookup(soinfo* si, unsigned hash, const char* name) {
ElfW(Sym)* symtab = si->symtab;
const char* strtab = si->strtab;
TRACE_TYPE(LOOKUP, "SEARCH %s in %s@%p %x %zd",
name, si->name, reinterpret_cast<void*>(si->base), hash, hash % si->nbucket);
for (unsigned n = si->bucket[hash % si->nbucket]; n != 0; n = si->chain[n]) {
ElfW(Sym)* s = symtab + n;
if (strcmp(strtab + s->st_name, name)) continue;
/* only concern ourselves with global and weak symbol definitions */
switch (ELF_ST_BIND(s->st_info)) {
case STB_GLOBAL:
case STB_WEAK:
// ARC MOD BEGIN
// We treat STB_GNU_UNIQUE as STB_GLOBAL.
// TODO(crbug.com/306079): Check if this is OK and implement
// STB_GNU_UNIQUE support if necessary.
#define STB_GNU_UNIQUE 10
case STB_GNU_UNIQUE:
// ARC MOD END
if (s->st_shndx == SHN_UNDEF) {
continue;
}
TRACE_TYPE(LOOKUP, "FOUND %s in %s (%p) %zd",
name, si->name, reinterpret_cast<void*>(s->st_value),
static_cast<size_t>(s->st_size));
return s;
case STB_LOCAL:
continue;
default:
__libc_fatal("ERROR: Unexpected ST_BIND value: %d for '%s' in '%s'",
ELF_ST_BIND(s->st_info), name, si->name);
}
}
TRACE_TYPE(LOOKUP, "NOT FOUND %s in %s@%p %x %zd",
name, si->name, reinterpret_cast<void*>(si->base), hash, hash % si->nbucket);
return NULL;
}
static unsigned elfhash(const char* _name) {
const unsigned char* name = reinterpret_cast<const unsigned char*>(_name);
unsigned h = 0, g;
while (*name) {
h = (h << 4) + *name++;
g = h & 0xf0000000;
h ^= g;
h ^= g >> 24;
}
return h;
}
static ElfW(Sym)* soinfo_do_lookup(soinfo* si, const char* name, soinfo** lsi, soinfo* needed[]) {
unsigned elf_hash = elfhash(name);
ElfW(Sym)* s = NULL;
if (si != NULL && somain != NULL) {
/*
* Local scope is executable scope. Just start looking into it right away
* for the shortcut.
*/
if (si == somain) {
s = soinfo_elf_lookup(si, elf_hash, name);
if (s != NULL) {
*lsi = si;
goto done;
}
/* Next, look for it in the preloads list */
for (int i = 0; g_ld_preloads[i] != NULL; i++) {
s = soinfo_elf_lookup(g_ld_preloads[i], elf_hash, name);
if (s != NULL) {
*lsi = g_ld_preloads[i];
goto done;
}
}
} else {
/* Order of symbol lookup is controlled by DT_SYMBOLIC flag */
/*
* If this object was built with symbolic relocations disabled, the
* first place to look to resolve external references is the main
* executable.
*/
if (!si->has_DT_SYMBOLIC) {
// ARC MOD BEGIN bionic-linker-symbol-lookup-order
// For real Android apps, the main binary is app_process,
// which has no meaningful symbol and no lookup is done
// here. This code path would exist for non-app
// executables. On the other hand, arc.nexe has a lot of
// symbols. To emulate the behavior for app_process, we
// resolve no symbol here.
// TODO(crbug.com/368131): Add an integration test for this.
#if !defined(HAVE_ARC)
// ARC MOD END
DEBUG("%s: looking up %s in executable %s",
si->name, name, somain->name);
s = soinfo_elf_lookup(somain, elf_hash, name);
if (s != NULL) {
*lsi = somain;
goto done;
}
// ARC MOD BEGIN bionic-linker-symbol-lookup-order
#endif
// ARC MOD END
/* Next, look for it in the preloads list */
for (int i = 0; g_ld_preloads[i] != NULL; i++) {
s = soinfo_elf_lookup(g_ld_preloads[i], elf_hash, name);
if (s != NULL) {
*lsi = g_ld_preloads[i];
goto done;
}
}
}
/* Look for symbols in the local scope (the object who is
* searching). This happens with C++ templates on x86 for some
* reason.
*
* Notes on weak symbols:
* The ELF specs are ambiguous about treatment of weak definitions in
* dynamic linking. Some systems return the first definition found
* and some the first non-weak definition. This is system dependent.
* Here we return the first definition found for simplicity. */
s = soinfo_elf_lookup(si, elf_hash, name);
if (s != NULL) {
*lsi = si;
goto done;
}
/*
* If this object was built with -Bsymbolic and symbol is not found
* in the local scope, try to find the symbol in the main executable.
*/
if (si->has_DT_SYMBOLIC) {
// ARC MOD BEGIN bionic-linker-symbol-lookup-order
#if !defined(HAVE_ARC)
// ARC MOD END
DEBUG("%s: looking up %s in executable %s after local scope",
si->name, name, somain->name);
s = soinfo_elf_lookup(somain, elf_hash, name);
if (s != NULL) {
*lsi = somain;
goto done;
}
// ARC MOD BEGIN bionic-linker-symbol-lookup-order
#endif
// ARC MOD END
/* Next, look for it in the preloads list */
for (int i = 0; g_ld_preloads[i] != NULL; i++) {
s = soinfo_elf_lookup(g_ld_preloads[i], elf_hash, name);
if (s != NULL) {
*lsi = g_ld_preloads[i];
goto done;
}
}
}
}
}
for (int i = 0; needed[i] != NULL; i++) {
DEBUG("%s: looking up %s in %s",
si->name, name, needed[i]->name);
s = soinfo_elf_lookup(needed[i], elf_hash, name);
if (s != NULL) {
*lsi = needed[i];
goto done;
}
}
done:
if (s != NULL) {
TRACE_TYPE(LOOKUP, "si %s sym %s s->st_value = %p, "
"found in %s, base = %p, load bias = %p",
si->name, name, reinterpret_cast<void*>(s->st_value),
(*lsi)->name, reinterpret_cast<void*>((*lsi)->base),
reinterpret_cast<void*>((*lsi)->load_bias));
return s;
}
return NULL;
}
// Another soinfo list allocator to use in dlsym. We don't reuse
// SoinfoListAllocator because it is write-protected most of the time.
static LinkerAllocator<LinkedListEntry<soinfo>> g_soinfo_list_allocator_rw;
class SoinfoListAllocatorRW {
public:
static LinkedListEntry<soinfo>* alloc() {
return g_soinfo_list_allocator_rw.alloc();
}
static void free(LinkedListEntry<soinfo>* ptr) {
g_soinfo_list_allocator_rw.free(ptr);
}
};
// This is used by dlsym(3). It performs symbol lookup only within the
// specified soinfo object and its dependencies in breadth first order.
ElfW(Sym)* dlsym_handle_lookup(soinfo* si, soinfo** found, const char* name) {
LinkedList<soinfo, SoinfoListAllocatorRW> visit_list;
LinkedList<soinfo, SoinfoListAllocatorRW> visited;
visit_list.push_back(si);
soinfo* current_soinfo;
while ((current_soinfo = visit_list.pop_front()) != nullptr) {
if (visited.contains(current_soinfo)) {
continue;
}
ElfW(Sym)* result = soinfo_elf_lookup(current_soinfo, elfhash(name), name);
if (result != nullptr) {
*found = current_soinfo;
visit_list.clear();
visited.clear();
return result;
}
visited.push_back(current_soinfo);
current_soinfo->get_children().for_each([&](soinfo* child) {
visit_list.push_back(child);
});
}
visit_list.clear();
visited.clear();
return nullptr;
}
/* This is used by dlsym(3) to performs a global symbol lookup. If the
start value is null (for RTLD_DEFAULT), the search starts at the
beginning of the global solist. Otherwise the search starts at the
specified soinfo (for RTLD_NEXT).
*/
ElfW(Sym)* dlsym_linear_lookup(const char* name, soinfo** found, soinfo* start) {
unsigned elf_hash = elfhash(name);
if (start == NULL) {
start = solist;
}
ElfW(Sym)* s = NULL;
for (soinfo* si = start; (s == NULL) && (si != NULL); si = si->next) {
s = soinfo_elf_lookup(si, elf_hash, name);
if (s != NULL) {
*found = si;
break;
}
}
if (s != NULL) {
TRACE_TYPE(LOOKUP, "%s s->st_value = %p, found->base = %p",
name, reinterpret_cast<void*>(s->st_value), reinterpret_cast<void*>((*found)->base));
}
return s;
}
soinfo* find_containing_library(const void* p) {
ElfW(Addr) address = reinterpret_cast<ElfW(Addr)>(p);
for (soinfo* si = solist; si != NULL; si = si->next) {
if (address >= si->base && address - si->base < si->size) {
return si;
}
}
return NULL;
}
ElfW(Sym)* dladdr_find_symbol(soinfo* si, const void* addr) {
// ARC MOD BEGIN UPSTREAM bionic-fix-dladdr--main-binary
// Use si->load_bias instead of si->base. This si->base works for
// shared objects but does not work for the main binary. The load
// bias of a main binary is not as same as si->base of the main
// binary unless the binary is a PIE. For example, si->load_bias
// of a NaCl main binary is 0 but its base is 0x10000.
ElfW(Addr) soaddr = reinterpret_cast<ElfW(Addr)>(addr) - si->load_bias;
// ARC MOD END UPSTREAM
// Search the library's symbol table for any defined symbol which
// contains this address.
for (size_t i = 0; i < si->nchain; ++i) {
ElfW(Sym)* sym = &si->symtab[i];
if (sym->st_shndx != SHN_UNDEF &&
soaddr >= sym->st_value &&
soaddr < sym->st_value + sym->st_size) {
return sym;
}
}
return NULL;
}
// ARC MOD BEGIN
#if defined(HAVE_ARC)
static int open_library_nacl(const char* name) {
ScopedElapsedTimePrinter<__LINE__> printer(
"Called open_library_nacl for", name);
char buf[512];
// Once __inject_arc_linker_hooks has been called, we only use
// posix_translation based file descriptors, so we do not use
// __nacl_irt_open_resource.
if (g_resolve_symbol) {
// If |name| contains a slash, we have already tried to open this
// file in open_library().
if (strchr(name, '/'))
return -1;
__libc_format_buffer(buf, sizeof(buf), "/system/lib/%s", name);
return open(buf, O_RDONLY);
} else {
// If the name is a basename (does not start with /), prepend /lib/ to the
// path because that is what nacl_irt_open_resource expects.
if (name && name[0] != '/') {
__libc_format_buffer(buf, sizeof(buf), DL_DST_LIB "/%s", name);
name = buf;
}
// When the path starts with DL_DST_LIB, the file is specified by
// NaCl's NMF, which can be accessed only by open_resource IRT
// call. For this case, we need to call __nacl_irt_open_resource
// without trying stat for this file.
if (!memcmp(DL_DST_LIB "/", name, sizeof(DL_DST_LIB))) {
int fd;
if (__nacl_irt_open_resource(name, &fd) != 0)
return -1;
return fd;
}
return -1;
}
}
#endif
// ARC MOD END
// ARC MOD BEGIN bionic-linker-ndk-detection
// Add |is_in_vendor_lib| argument.
// TODO(crbug.com/364344): Remove /vendor/lib.
static int open_library_on_path(const char* name, const char* const paths[],
int* is_in_vendor_lib) {
// ARC MOD END
char buf[512];
for (size_t i = 0; paths[i] != NULL; ++i) {
int n = __libc_format_buffer(buf, sizeof(buf), "%s/%s", paths[i], name);
if (n < 0 || n >= static_cast<int>(sizeof(buf))) {
PRINT("Warning: ignoring very long library path: %s/%s", paths[i], name);
continue;
}
int fd = TEMP_FAILURE_RETRY(open(buf, O_RDONLY | O_CLOEXEC));
if (fd != -1) {
// ARC MOD BEGIN bionic-linker-ndk-detection
// Unlike the MOD in load_library, we do not need to check files
// in /data/app-lib as this path is not in LD_LIBRARY_PATH.
if (!strcmp(paths[i], kVendorLibDir)) {
*is_in_vendor_lib = 1;
}
// ARC MOD END
return fd;
}
}
return -1;
}
// ARC MOD BEGIN bionic-linker-ndk-detection
// Add |is_in_vendor_lib| argument.
// TODO(crbug.com/364344): Remove /vendor/lib.
static int open_library(const char* name, int* is_in_vendor_lib) {
// ARC MOD END
// ARC MOD BEGIN
// Note on which code path is used for which case:
//
// 1. DT_NEEDED specified by arc.nexe: We use
// __nacl_irt_open_resource() directly from open_library_nacl.
// 2. dlopen for binaries in arc.nmf (e.g., libEGL_emulation.so):
// If a fullpath is not specified, we prepend /system/lib and
// call open() from open_library_nacl or open_library. As
// __inject_arc_linker_hooks replaces __nacl_irt_open, this is
// handled by posix_translation and it calls
// __nacl_irt_open_resource().
// 3. dlopen for NDK binaries (NDK direct execution mode only): We
// call open() from open_library. This will be handled by
// posix_translation and PepperFileHandler handles this.
// 4. DT_NEEDED specified by unit tests: We use open() in
// open_library_on_path. Note that we rely on LD_LIBRARY_PATH
// specified by our unit test runner.
// 5. dlopen from unit tests: Like 4, we use open in
// open_library_on_path(). __inject_arc_linker_hooks has been
// already called so the implementation of __nacl_irt_open is
// hooked, but it ends up calling real open() for unit tests.
//
// ARC MOD END
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, '/') != NULL) {
int fd = TEMP_FAILURE_RETRY(open(name, O_RDONLY | O_CLOEXEC));
if (fd != -1) {
return fd;
}
// ...but nvidia binary blobs (at least) rely on this behavior, so fall through for now.
// ARC MOD BEGIN
// We always need to try open_library_nacl. So we will never
// return here. Although we do not need this MOD right now as we
// do not define __LP64__, this "return -1" is likely to be
// removed in future, so we explicitly have !HAVE_ARC here.
#if defined(__LP64__) && !defined(HAVE_ARC)
// ARC MOD END
return -1;
#endif
}
// ARC MOD BEGIN
#if defined(HAVE_ARC)
int naclfd = open_library_nacl(name);
if (naclfd != -1)
return naclfd;
// Note: Our unit tests need open_library_on_path calls below since
// the test binaries have DT_NEEDED entries like "libc.so" and such
// DT_NEEDED libraries live in a path like
// "out/target/nacl_i686_opt/lib/", not in "/lib". Also note that
// open_library_on_path does nothing as |g_ld_library_paths| is
// empty on production ARC and therefore is fast.
return open_library_on_path(name, g_ld_library_paths, is_in_vendor_lib);
// We have already tried /system/lib by __nacl_irt_open_resource
// (before __inject_arc_linker_hooks) or __nacl_irt_open (after
// __inject_arc_linker_hooks, so retrying with kDefaultLdPaths does
// not make sense for us. Not to call open_resource IRT which
// synchronizes with the renderer, disable the slow fallback path.
#else
// ARC MOD END
// Otherwise we try LD_LIBRARY_PATH first, and fall back to the built-in well known paths.
// ARC MOD BEGIN bionic-linker-ndk-detection
int fd = open_library_on_path(name, g_ld_library_paths, is_in_vendor_lib);
// ARC MOD END
if (fd == -1) {
// ARC MOD BEGIN bionic-linker-ndk-detection
fd = open_library_on_path(name, kDefaultLdPaths, is_in_vendor_lib);
// ARC MOD END
}
return fd;
// ARC MOD BEGIN
#endif
// ARC MOD END
}
static soinfo* load_library(const char* name, int dlflags, const android_dlextinfo* extinfo) {
int fd = -1;
ScopedFd file_guard(-1);
// ARC MOD BEGIN bionic-linker-ndk-detection
int is_in_vendor_lib = 0;
// ARC MOD END
if (extinfo != NULL && (extinfo->flags & ANDROID_DLEXT_USE_LIBRARY_FD) != 0) {
fd = extinfo->library_fd;
} else {
// Open the file.
// ARC MOD BEGIN bionic-linker-ndk-detection
// Pass |is_in_vendor_lib| to open_library.
// TODO(crbug.com/364344): Remove /vendor/lib.
fd = open_library(name, &is_in_vendor_lib);
// ARC MOD END
if (fd == -1) {
DL_ERR("library \"%s\" not found", name);
return NULL;
}
file_guard.reset(fd);
}
ElfReader elf_reader(name, fd);
struct stat file_stat;
if (TEMP_FAILURE_RETRY(fstat(fd, &file_stat)) != 0) {
DL_ERR("unable to stat file for the library %s: %s", name, strerror(errno));
return NULL;
}
// Check for symlink and other situations where
// file can have different names.
for (soinfo* si = solist; si != NULL; 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) {
TRACE("library \"%s\" is already loaded under different name/path \"%s\" - will return existing soinfo", name, si->name);
return si;
}
}
if ((dlflags & RTLD_NOLOAD) != 0) {
return NULL;
}
// Read the ELF header and load the segments.
if (!elf_reader.Load(extinfo)) {
return NULL;
}
// ARC MOD BEGIN
// SEARCH_NAME() returns the base name for 32-bit platforms.
// For compatibility, we keep this behavior, and provide library search
// paths to GDB so that GDB can find the libraries from their base names.
// See src/build/run_under_gdb.py.
// ARC MOD END
soinfo* si = soinfo_alloc(SEARCH_NAME(name), &file_stat);
if (si == NULL) {
return NULL;
}
si->base = elf_reader.load_start();
si->size = elf_reader.load_size();
si->load_bias = elf_reader.load_bias();
si->phnum = elf_reader.phdr_count();
si->phdr = elf_reader.loaded_phdr();
// ARC MOD BEGIN
#if defined(HAVE_ARC)
// Linux kernel sends the entry point using AT_ENTRY, but sel_ldr
// does not send this info. Take this occasion and fill the field.
const ElfW(Ehdr)& header = elf_reader.header();
if (header.e_entry)
si->entry = header.e_entry + elf_reader.load_bias();
if (!si->phdr)
DL_ERR("Cannot locate a program header in \"%s\".", name);
// ARC MOD END
// ARC MOD BEGIN bionic-linker-ndk-detection
// Set is_ndk appropriately. NDK libraries in APKs are in
// /data/app-lib/<app-name>.
const char kNdkLibraryDir[] = "/data/app-lib/";
// Or, Google Play Services (and maybe other apps) may load ndk libraries
// placed by the app itself on the data directory /data/data/<app-name>.
const char kAppDataDir[] = "/data/data/";
si->is_ndk = (is_in_vendor_lib ||
!strncmp(name, kNdkLibraryDir, sizeof(kNdkLibraryDir) - 1) ||
!strncmp(name, kAppDataDir, sizeof(kAppDataDir) - 1) ||
!strncmp(name, kVendorLibDir, sizeof(kVendorLibDir) - 1));
#endif
// ARC MOD END
// At this point we know that whatever is loaded @ base is a valid ELF
// shared library whose segments are properly mapped in.
TRACE("[ load_library base=%p size=%zu name='%s' ]",
reinterpret_cast<void*>(si->base), si->size, si->name);
// ARC MOD BEGIN
// Set |somain| and FLAG_EXE for the main binary. They are
// needed to be set in soinfo_link_image. In the upstream Bionic
// loader, this is done in __linker_init_post_relocation before
// soinfo_link_image is called. See the comment for
// load_main_binary for this difference.
// Also we fill _r_debug here to insert somain first.
#if defined(HAVE_ARC)
if (!somain) {
TRACE("[ Setting %s as somain ]", si->name);
somain = si;
somain->flags |= FLAG_EXE;
link_map* map = &(si->link_map_head);
map->l_addr = 0;
map->l_name = const_cast<char*>(name);
map->l_prev = NULL;
map->l_next = NULL;
_r_debug.r_map = map;
r_debug_tail = map;
}
#endif
// ARC MOD END
if (!soinfo_link_image(si, extinfo)) {
// ARC MOD BEGIN
// We do not have the size of data segments so we cannot unmap
// data segments.
// TODO(crbug.com/257546): Unmap data segments.
// ARC MOD END
soinfo_free(si);
return NULL;
}
return si;
}
static soinfo *find_loaded_library_by_name(const char* name) {
const char* search_name = SEARCH_NAME(name);
for (soinfo* si = solist; si != NULL; si = si->next) {
if (!strcmp(search_name, si->name)) {
return si;
}
}
return NULL;
}
static soinfo* find_library_internal(const char* name, int dlflags, const android_dlextinfo* extinfo) {
if (name == NULL) {
return somain;
}
soinfo* si = find_loaded_library_by_name(name);
// Library might still be loaded, the accurate detection
// of this fact is done by load_library
if (si == NULL) {
TRACE("[ '%s' has not been found by name. Trying harder...]", name);
si = load_library(name, dlflags, extinfo);
}
if (si != NULL && (si->flags & FLAG_LINKED) == 0) {
DL_ERR("recursive link to \"%s\"", si->name);
return NULL;
}
return si;
}
static soinfo* find_library(const char* name, int dlflags, const android_dlextinfo* extinfo) {
soinfo* si = find_library_internal(name, dlflags, extinfo);
if (si != NULL) {
si->ref_count++;
}
return si;
}
static void soinfo_unload(soinfo* si) {
if (si->ref_count == 1) {
TRACE("unloading '%s'", si->name);
si->CallDestructors();
if ((si->flags | FLAG_NEW_SOINFO) != 0) {
si->get_children().for_each([&] (soinfo* child) {
TRACE("%s needs to unload %s", si->name, child->name);
soinfo_unload(child);
});
} else {
for (ElfW(Dyn)* d = si->dynamic; d->d_tag != DT_NULL; ++d) {
if (d->d_tag == DT_NEEDED) {
const char* library_name = si->strtab + d->d_un.d_val;
TRACE("%s needs to unload %s", si->name, library_name);
soinfo* needed = find_library(library_name, RTLD_NOLOAD, NULL);
if (needed != NULL) {
soinfo_unload(needed);
} else {
// Not found: for example if symlink was deleted between dlopen and dlclose
// Since we cannot really handle errors at this point - print and continue.
PRINT("warning: couldn't find %s needed by %s on unload.", library_name, si->name);
}
}
}
}
notify_gdb_of_unload(si);
si->ref_count = 0;
soinfo_free(si);
} else {
si->ref_count--;
TRACE("not unloading '%s', decrementing ref_count to %zd", si->name, si->ref_count);
}
}
void do_android_get_LD_LIBRARY_PATH(char* buffer, size_t buffer_size) {
// Use basic string manipulation calls to avoid snprintf.
// snprintf indirectly calls pthread_getspecific to get the size of a buffer.
// When debug malloc is enabled, this call returns 0. This in turn causes
// snprintf to do nothing, which causes libraries to fail to load.
// See b/17302493 for further details.
// Once the above bug is fixed, this code can be modified to use
// snprintf again.
size_t required_len = strlen(kDefaultLdPaths[0]) + strlen(kDefaultLdPaths[1]) + 2;
if (buffer_size < required_len) {
__libc_fatal("android_get_LD_LIBRARY_PATH failed, buffer too small: buffer len %zu, required len %zu",
buffer_size, required_len);
}
char* end = stpcpy(buffer, kDefaultLdPaths[0]);
*end = ':';
strcpy(end + 1, kDefaultLdPaths[1]);
}
void do_android_update_LD_LIBRARY_PATH(const char* ld_library_path) {
if (!get_AT_SECURE()) {
parse_LD_LIBRARY_PATH(ld_library_path);
}
}
soinfo* do_dlopen(const char* name, int flags, const android_dlextinfo* extinfo) {
if ((flags & ~(RTLD_NOW|RTLD_LAZY|RTLD_LOCAL|RTLD_GLOBAL|RTLD_NOLOAD)) != 0) {
DL_ERR("invalid flags to dlopen: %x", flags);
return NULL;
}
if (extinfo != NULL && ((extinfo->flags & ~(ANDROID_DLEXT_VALID_FLAG_BITS)) != 0)) {
DL_ERR("invalid extended flags to android_dlopen_ext: %" PRIx64, extinfo->flags);
return NULL;
}
protect_data(PROT_READ | PROT_WRITE);
soinfo* si = find_library(name, flags, extinfo);
if (si != NULL) {
si->CallConstructors();
}
protect_data(PROT_READ);
return si;
}
void do_dlclose(soinfo* si) {
protect_data(PROT_READ | PROT_WRITE);
soinfo_unload(si);
protect_data(PROT_READ);
}
#if defined(USE_RELA)
static int soinfo_relocate(soinfo* si, ElfW(Rela)* rela, unsigned count, soinfo* needed[]) {
// ARC MOD BEGIN
// Initialize |s| by NULL.
ElfW(Sym)* s = NULL;
// ARC MOD END
// ARC MOD BEGIN
// Initialize |lsi| by NULL to remove GCC -O2 warnings.
soinfo* lsi = NULL;
// ARC MOD END
for (size_t idx = 0; idx < count; ++idx, ++rela) {
unsigned type = ELFW(R_TYPE)(rela->r_info);
unsigned sym = ELFW(R_SYM)(rela->r_info);
ElfW(Addr) reloc = static_cast<ElfW(Addr)>(rela->r_offset + si->load_bias);
ElfW(Addr) sym_addr = 0;
const char* sym_name = NULL;
DEBUG("Processing '%s' relocation at index %zd", si->name, idx);
if (type == 0) { // R_*_NONE
continue;
}
if (sym != 0) {
sym_name = reinterpret_cast<const char*>(si->strtab + si->symtab[sym].st_name);
// ARC MOD BEGIN bionic-linker-symbol-lookup-order
// We must not look up local symbols. RESOLVE_MAP in
// nacl-glibc/elf/dl-reloc.c handles local symbols similarly.
//
// We treat all symbols in the Bionic loader as
// local. When we are relocating the Bionic loader, it
// cannot use lookup() because libdl_info in dlfcn.c is
// not relocated yet. Upstream Bionic may not have this
// issue because it uses RTLD_LOCAL semantics.
//
// We also modified code in else clause for ARC. See the
// comment in the else clause for detail.
if(ELFW(ST_BIND)(si->symtab[sym].st_info) == STB_LOCAL ||
// TODO(yusukes): Check if this is still necessary.
(si->flags & FLAG_LINKER) == FLAG_LINKER) {
s = &si->symtab[sym];
lsi = si;
} else {
#if defined(HAVE_ARC)
// If |g_resolve_symbol| is injected, try this first.
if (g_resolve_symbol) {
sym_addr = reinterpret_cast<ElfW(Addr)>(
g_resolve_symbol(sym_name));
if (sym_addr) {
goto symbol_found;
}
}
// Then look up the symbol following Android's default
// semantics.
s = soinfo_do_lookup(si, sym_name, &lsi, needed);
// When the symbol is not found, we still need to
// look up the main binary, as we link some shared
// objects (e.g., liblog.so) into arc.nexe
// TODO(crbug.com/400947): Remove this code once we have
// stopped converting .so files to .a.
if (!s)
s = soinfo_do_lookup(somain, sym_name, &lsi, needed);
#else
s = soinfo_do_lookup(si, sym_name, &lsi, needed);
#endif
}
// ARC MOD END
if (s == NULL) {
// We only allow an undefined symbol if this is a weak reference...
s = &si->symtab[sym];
if (ELF_ST_BIND(s->st_info) != STB_WEAK) {
DL_ERR("cannot locate symbol \"%s\" referenced by \"%s\"...", sym_name, si->name);
return -1;
}
/* IHI0044C AAELF 4.5.1.1:
Libraries are not searched to resolve weak references.
It is not an error for a weak reference to remain unsatisfied.
During linking, the value of an undefined weak reference is:
- Zero if the relocation type is absolute
- The address of the place if the relocation is pc-relative
- The address of nominal base address if the relocation
type is base-relative.
*/
switch (type) {
#if defined(__aarch64__)
case R_AARCH64_JUMP_SLOT:
case R_AARCH64_GLOB_DAT:
case R_AARCH64_ABS64:
case R_AARCH64_ABS32:
case R_AARCH64_ABS16:
case R_AARCH64_RELATIVE:
/*
* The sym_addr was initialized to be zero above, or the relocation
* code below does not care about value of sym_addr.
* No need to do anything.
*/
break;
#elif defined(__x86_64__)
case R_X86_64_JUMP_SLOT:
case R_X86_64_GLOB_DAT:
case R_X86_64_32:
case R_X86_64_64:
case R_X86_64_RELATIVE:
// No need to do anything.
break;
case R_X86_64_PC32:
sym_addr = reloc;
break;
#endif
default:
DL_ERR("unknown weak reloc type %d @ %p (%zu)", type, rela, idx);
return -1;
}
} else {
// We got a definition.
sym_addr = static_cast<ElfW(Addr)>(s->st_value + lsi->load_bias);
}
// ARC MOD BEGIN
// Add symbol_found label.
#if defined(HAVE_ARC)
symbol_found:
#endif
// ARC MOD END
count_relocation(kRelocSymbol);
} else {
s = NULL;
}
switch (type) {
#if defined(__aarch64__)
case R_AARCH64_JUMP_SLOT:
count_relocation(kRelocAbsolute);
MARK(rela->r_offset);
TRACE_TYPE(RELO, "RELO JMP_SLOT %16llx <- %16llx %s\n",
reloc, (sym_addr + rela->r_addend), sym_name);
*reinterpret_cast<ElfW(Addr)*>(reloc) = (sym_addr + rela->r_addend);
break;
case R_AARCH64_GLOB_DAT:
count_relocation(kRelocAbsolute);
MARK(rela->r_offset);
TRACE_TYPE(RELO, "RELO GLOB_DAT %16llx <- %16llx %s\n",
reloc, (sym_addr + rela->r_addend), sym_name);
*reinterpret_cast<ElfW(Addr)*>(reloc) = (sym_addr + rela->r_addend);
break;
case R_AARCH64_ABS64:
count_relocation(kRelocAbsolute);
MARK(rela->r_offset);
TRACE_TYPE(RELO, "RELO ABS64 %16llx <- %16llx %s\n",
reloc, (sym_addr + rela->r_addend), sym_name);
*reinterpret_cast<ElfW(Addr)*>(reloc) += (sym_addr + rela->r_addend);
break;
case R_AARCH64_ABS32:
count_relocation(kRelocAbsolute);
MARK(rela->r_offset);
TRACE_TYPE(RELO, "RELO ABS32 %16llx <- %16llx %s\n",
reloc, (sym_addr + rela->r_addend), sym_name);
if ((static_cast<ElfW(Addr)>(INT32_MIN) <= (*reinterpret_cast<ElfW(Addr)*>(reloc) + (sym_addr + rela->r_addend))) &&
((*reinterpret_cast<ElfW(Addr)*>(reloc) + (sym_addr + rela->r_addend)) <= static_cast<ElfW(Addr)>(UINT32_MAX))) {
*reinterpret_cast<ElfW(Addr)*>(reloc) += (sym_addr + rela->r_addend);
} else {
DL_ERR("0x%016llx out of range 0x%016llx to 0x%016llx",
(*reinterpret_cast<ElfW(Addr)*>(reloc) + (sym_addr + rela->r_addend)),
static_cast<ElfW(Addr)>(INT32_MIN),
static_cast<ElfW(Addr)>(UINT32_MAX));
return -1;
}
break;
case R_AARCH64_ABS16:
count_relocation(kRelocAbsolute);
MARK(rela->r_offset);
TRACE_TYPE(RELO, "RELO ABS16 %16llx <- %16llx %s\n",
reloc, (sym_addr + rela->r_addend), sym_name);
if ((static_cast<ElfW(Addr)>(INT16_MIN) <= (*reinterpret_cast<ElfW(Addr)*>(reloc) + (sym_addr + rela->r_addend))) &&
((*reinterpret_cast<ElfW(Addr)*>(reloc) + (sym_addr + rela->r_addend)) <= static_cast<ElfW(Addr)>(UINT16_MAX))) {
*reinterpret_cast<ElfW(Addr)*>(reloc) += (sym_addr + rela->r_addend);
} else {
DL_ERR("0x%016llx out of range 0x%016llx to 0x%016llx",
(*reinterpret_cast<ElfW(Addr)*>(reloc) + (sym_addr + rela->r_addend)),
static_cast<ElfW(Addr)>(INT16_MIN),
static_cast<ElfW(Addr)>(UINT16_MAX));
return -1;
}
break;
case R_AARCH64_PREL64:
count_relocation(kRelocRelative);
MARK(rela->r_offset);
TRACE_TYPE(RELO, "RELO REL64 %16llx <- %16llx - %16llx %s\n",
reloc, (sym_addr + rela->r_addend), rela->r_offset, sym_name);
*reinterpret_cast<ElfW(Addr)*>(reloc) += (sym_addr + rela->r_addend) - rela->r_offset;
break;
case R_AARCH64_PREL32:
count_relocation(kRelocRelative);
MARK(rela->r_offset);
TRACE_TYPE(RELO, "RELO REL32 %16llx <- %16llx - %16llx %s\n",
reloc, (sym_addr + rela->r_addend), rela->r_offset, sym_name);
if ((static_cast<ElfW(Addr)>(INT32_MIN) <= (*reinterpret_cast<ElfW(Addr)*>(reloc) + ((sym_addr + rela->r_addend) - rela->r_offset))) &&
((*reinterpret_cast<ElfW(Addr)*>(reloc) + ((sym_addr + rela->r_addend) - rela->r_offset)) <= static_cast<ElfW(Addr)>(UINT32_MAX))) {
*reinterpret_cast<ElfW(Addr)*>(reloc) += ((sym_addr + rela->r_addend) - rela->r_offset);
} else {
DL_ERR("0x%016llx out of range 0x%016llx to 0x%016llx",
(*reinterpret_cast<ElfW(Addr)*>(reloc) + ((sym_addr + rela->r_addend) - rela->r_offset)),
static_cast<ElfW(Addr)>(INT32_MIN),
static_cast<ElfW(Addr)>(UINT32_MAX));
return -1;
}
break;
case R_AARCH64_PREL16:
count_relocation(kRelocRelative);
MARK(rela->r_offset);
TRACE_TYPE(RELO, "RELO REL16 %16llx <- %16llx - %16llx %s\n",
reloc, (sym_addr + rela->r_addend), rela->r_offset, sym_name);
if ((static_cast<ElfW(Addr)>(INT16_MIN) <= (*reinterpret_cast<ElfW(Addr)*>(reloc) + ((sym_addr + rela->r_addend) - rela->r_offset))) &&
((*reinterpret_cast<ElfW(Addr)*>(reloc) + ((sym_addr + rela->r_addend) - rela->r_offset)) <= static_cast<ElfW(Addr)>(UINT16_MAX))) {
*reinterpret_cast<ElfW(Addr)*>(reloc) += ((sym_addr + rela->r_addend) - rela->r_offset);
} else {
DL_ERR("0x%016llx out of range 0x%016llx to 0x%016llx",
(*reinterpret_cast<ElfW(Addr)*>(reloc) + ((sym_addr + rela->r_addend) - rela->r_offset)),
static_cast<ElfW(Addr)>(INT16_MIN),
static_cast<ElfW(Addr)>(UINT16_MAX));
return -1;
}
break;
case R_AARCH64_RELATIVE:
count_relocation(kRelocRelative);
MARK(rela->r_offset);
if (sym) {
DL_ERR("odd RELATIVE form...");
return -1;
}
TRACE_TYPE(RELO, "RELO RELATIVE %16llx <- %16llx\n",
reloc, (si->base + rela->r_addend));
*reinterpret_cast<ElfW(Addr)*>(reloc) = (si->base + rela->r_addend);
break;
case R_AARCH64_COPY:
/*
* ET_EXEC is not supported so this should not happen.
*
* http://infocenter.arm.com/help/topic/com.arm.doc.ihi0044d/IHI0044D_aaelf.pdf
*
* Section 4.7.1.10 "Dynamic relocations"
* R_AARCH64_COPY may only appear in executable objects where e_type is
* set to ET_EXEC.
*/
DL_ERR("%s R_AARCH64_COPY relocations are not supported", si->name);
return -1;
case R_AARCH64_TLS_TPREL64:
TRACE_TYPE(RELO, "RELO TLS_TPREL64 *** %16llx <- %16llx - %16llx\n",
reloc, (sym_addr + rela->r_addend), rela->r_offset);
break;
case R_AARCH64_TLS_DTPREL32:
TRACE_TYPE(RELO, "RELO TLS_DTPREL32 *** %16llx <- %16llx - %16llx\n",
reloc, (sym_addr + rela->r_addend), rela->r_offset);
break;
#elif defined(__x86_64__)
case R_X86_64_JUMP_SLOT:
count_relocation(kRelocAbsolute);
MARK(rela->r_offset);
TRACE_TYPE(RELO, "RELO JMP_SLOT %08zx <- %08zx %s", static_cast<size_t>(reloc),
static_cast<size_t>(sym_addr + rela->r_addend), sym_name);
*reinterpret_cast<ElfW(Addr)*>(reloc) = sym_addr + rela->r_addend;
break;
case R_X86_64_GLOB_DAT:
count_relocation(kRelocAbsolute);
MARK(rela->r_offset);
TRACE_TYPE(RELO, "RELO GLOB_DAT %08zx <- %08zx %s", static_cast<size_t>(reloc),
static_cast<size_t>(sym_addr + rela->r_addend), sym_name);
*reinterpret_cast<ElfW(Addr)*>(reloc) = sym_addr + rela->r_addend;
break;
case R_X86_64_RELATIVE:
count_relocation(kRelocRelative);
MARK(rela->r_offset);
if (sym) {
DL_ERR("odd RELATIVE form...");
return -1;
}
TRACE_TYPE(RELO, "RELO RELATIVE %08zx <- +%08zx", static_cast<size_t>(reloc),
static_cast<size_t>(si->base));
*reinterpret_cast<ElfW(Addr)*>(reloc) = si->base + rela->r_addend;
break;
case R_X86_64_32:
count_relocation(kRelocRelative);
MARK(rela->r_offset);
TRACE_TYPE(RELO, "RELO R_X86_64_32 %08zx <- +%08zx %s", static_cast<size_t>(reloc),
static_cast<size_t>(sym_addr), sym_name);
// ARC MOD BEGIN UPSTREAM bionic-x86-64-32bit-relocation
// R_X86_64_32 writes a 32 bit address value to memory instead
// of 64 bit (ElfW(Addr)).
*reinterpret_cast<Elf32_Addr*>(reloc) = sym_addr + rela->r_addend;
// ARC MOD END UPSTREAM
break;
case R_X86_64_64:
count_relocation(kRelocRelative);
MARK(rela->r_offset);
TRACE_TYPE(RELO, "RELO R_X86_64_64 %08zx <- +%08zx %s", static_cast<size_t>(reloc),
static_cast<size_t>(sym_addr), sym_name);
*reinterpret_cast<ElfW(Addr)*>(reloc) = sym_addr + rela->r_addend;
break;
case R_X86_64_PC32:
count_relocation(kRelocRelative);
MARK(rela->r_offset);
TRACE_TYPE(RELO, "RELO R_X86_64_PC32 %08zx <- +%08zx (%08zx - %08zx) %s",
static_cast<size_t>(reloc), static_cast<size_t>(sym_addr - reloc),
static_cast<size_t>(sym_addr), static_cast<size_t>(reloc), sym_name);
// ARC MOD BEGIN UPSTREAM bionic-x86-64-32bit-relocation
// R_X86_64_PC32 writes a 32 bit address value to memory instead
// of 64 bit (ElfW(Addr)).
*reinterpret_cast<Elf32_Addr*>(reloc) = sym_addr + rela->r_addend - reloc;
// ARC MOD END UPSTREAM
break;
#endif
default:
DL_ERR("unknown reloc type %d @ %p (%zu)", type, rela, idx);
return -1;
}
}
return 0;
}
#else // REL, not RELA.
static int soinfo_relocate(soinfo* si, ElfW(Rel)* rel, unsigned count, soinfo* needed[]) {
// ARC MOD BEGIN
// Initialize |s| by NULL.
ElfW(Sym)* s = NULL;
// ARC MOD END
// ARC MOD BEGIN
// Initialize |lsi| by NULL to remove GCC -O2 warnings.
soinfo* lsi = NULL;
// ARC MOD END
for (size_t idx = 0; idx < count; ++idx, ++rel) {
unsigned type = ELFW(R_TYPE)(rel->r_info);
// TODO: don't use unsigned for 'sym'. Use uint32_t or ElfW(Addr) instead.
unsigned sym = ELFW(R_SYM)(rel->r_info);
ElfW(Addr) reloc = static_cast<ElfW(Addr)>(rel->r_offset + si->load_bias);
ElfW(Addr) sym_addr = 0;
const char* sym_name = NULL;
DEBUG("Processing '%s' relocation at index %zd", si->name, idx);
if (type == 0) { // R_*_NONE
continue;
}
if (sym != 0) {
sym_name = reinterpret_cast<const char*>(si->strtab + si->symtab[sym].st_name);
// ARC MOD BEGIN
// We must not look up local symbols. RESOLVE_MAP in
// nacl-glibc/elf/dl-reloc.c handles local symbols similarly.
//
// We treat all symbols in the Bionic loader as
// local. When we are relocating the Bionic loader, it
// cannot use lookup() because libdl_info in dlfcn.c is
// not relocated yet. Upstream Bionic may not have this
// issue because it uses RTLD_LOCAL semantics.
//
// We also modified code in else clause for ARC. See the
// comment in the else clause for detail.
if(ELFW(ST_BIND)(si->symtab[sym].st_info) == STB_LOCAL ||
// TODO(yusukes): Check if this is still necessary.
(si->flags & FLAG_LINKER) == FLAG_LINKER) {
s = &si->symtab[sym];
lsi = si;
} else {
#if defined(HAVE_ARC)
// If |g_resolve_symbol| is injected, try this first for NDK.
if (si->is_ndk && g_resolve_symbol) {
sym_addr = reinterpret_cast<Elf32_Addr>(
g_resolve_symbol(sym_name));
if (sym_addr) {
goto symbol_found;
}
}
// ARC MOD END
// ARC MOD BEGIN
// Then look up the symbol following Android's default
// semantics.
s = soinfo_do_lookup(si, sym_name, &lsi, needed);
// When the symbol is not found, we still need to
// look up the main binary, as we link some shared
// objects (e.g., liblog.so) into arc.nexe
// TODO(crbug.com/400947): Remove this code once we have
// stopped converting .so files to .a.
if (!s)
s = soinfo_do_lookup(somain, sym_name, &lsi, needed);
#else
s = soinfo_do_lookup(si, sym_name, &lsi, needed);
#endif
}
// ARC MOD END
if (s == NULL) {
// We only allow an undefined symbol if this is a weak reference...
s = &si->symtab[sym];
if (ELF_ST_BIND(s->st_info) != STB_WEAK) {
DL_ERR("cannot locate symbol \"%s\" referenced by \"%s\"...", sym_name, si->name);
return -1;
}
/* IHI0044C AAELF 4.5.1.1:
Libraries are not searched to resolve weak references.
It is not an error for a weak reference to remain
unsatisfied.
During linking, the value of an undefined weak reference is:
- Zero if the relocation type is absolute
- The address of the place if the relocation is pc-relative
- The address of nominal base address if the relocation
type is base-relative.
*/
switch (type) {
#if defined(__arm__)
case R_ARM_JUMP_SLOT:
case R_ARM_GLOB_DAT:
case R_ARM_ABS32:
case R_ARM_RELATIVE: /* Don't care. */
// sym_addr was initialized to be zero above or relocation
// code below does not care about value of sym_addr.
// No need to do anything.
break;
#elif defined(__i386__)
case R_386_JMP_SLOT:
case R_386_GLOB_DAT:
case R_386_32:
case R_386_RELATIVE: /* Don't care. */
// sym_addr was initialized to be zero above or relocation
// code below does not care about value of sym_addr.
// No need to do anything.
break;
case R_386_PC32:
sym_addr = reloc;
break;
#endif
#if defined(__arm__)
case R_ARM_COPY:
// Fall through. Can't really copy if weak symbol is not found at run-time.
#endif
default:
DL_ERR("unknown weak reloc type %d @ %p (%zu)", type, rel, idx);
return -1;
}
} else {
// We got a definition.
sym_addr = static_cast<ElfW(Addr)>(s->st_value + lsi->load_bias);
}
// ARC MOD BEGIN
// Add symbol_found label.
#if defined(HAVE_ARC)
symbol_found:
#endif
// ARC MOD END
count_relocation(kRelocSymbol);
} else {
s = NULL;
}
switch (type) {
#if defined(__arm__)
case R_ARM_JUMP_SLOT:
count_relocation(kRelocAbsolute);
MARK(rel->r_offset);
TRACE_TYPE(RELO, "RELO JMP_SLOT %08x <- %08x %s", reloc, sym_addr, sym_name);
*reinterpret_cast<ElfW(Addr)*>(reloc) = sym_addr;
break;
case R_ARM_GLOB_DAT:
count_relocation(kRelocAbsolute);
MARK(rel->r_offset);
TRACE_TYPE(RELO, "RELO GLOB_DAT %08x <- %08x %s", reloc, sym_addr, sym_name);
*reinterpret_cast<ElfW(Addr)*>(reloc) = sym_addr;
break;
case R_ARM_ABS32:
count_relocation(kRelocAbsolute);
MARK(rel->r_offset);
TRACE_TYPE(RELO, "RELO ABS %08x <- %08x %s", reloc, sym_addr, sym_name);
*reinterpret_cast<ElfW(Addr)*>(reloc) += sym_addr;
break;
case R_ARM_REL32:
count_relocation(kRelocRelative);
MARK(rel->r_offset);
TRACE_TYPE(RELO, "RELO REL32 %08x <- %08x - %08x %s",
reloc, sym_addr, rel->r_offset, sym_name);
*reinterpret_cast<ElfW(Addr)*>(reloc) += sym_addr - rel->r_offset;
break;
case R_ARM_COPY:
/*
* ET_EXEC is not supported so this should not happen.
*
* http://infocenter.arm.com/help/topic/com.arm.doc.ihi0044d/IHI0044D_aaelf.pdf
*
* Section 4.7.1.10 "Dynamic relocations"
* R_ARM_COPY may only appear in executable objects where e_type is
* set to ET_EXEC.
*/
DL_ERR("%s R_ARM_COPY relocations are not supported", si->name);
return -1;
#elif defined(__i386__)
case R_386_JMP_SLOT:
count_relocation(kRelocAbsolute);
MARK(rel->r_offset);
TRACE_TYPE(RELO, "RELO JMP_SLOT %08x <- %08x %s", reloc, sym_addr, sym_name);
*reinterpret_cast<ElfW(Addr)*>(reloc) = sym_addr;
break;
case R_386_GLOB_DAT:
count_relocation(kRelocAbsolute);
MARK(rel->r_offset);
TRACE_TYPE(RELO, "RELO GLOB_DAT %08x <- %08x %s", reloc, sym_addr, sym_name);
*reinterpret_cast<ElfW(Addr)*>(reloc) = sym_addr;
break;
case R_386_32:
count_relocation(kRelocRelative);
MARK(rel->r_offset);
TRACE_TYPE(RELO, "RELO R_386_32 %08x <- +%08x %s", reloc, sym_addr, sym_name);
*reinterpret_cast<ElfW(Addr)*>(reloc) += sym_addr;
break;
case R_386_PC32:
count_relocation(kRelocRelative);
MARK(rel->r_offset);
TRACE_TYPE(RELO, "RELO R_386_PC32 %08x <- +%08x (%08x - %08x) %s",
reloc, (sym_addr - reloc), sym_addr, reloc, sym_name);
*reinterpret_cast<ElfW(Addr)*>(reloc) += (sym_addr - reloc);
break;
#elif defined(__mips__)
case R_MIPS_REL32:
#if defined(__LP64__)
// MIPS Elf64_Rel entries contain compound relocations
// We only handle the R_MIPS_NONE|R_MIPS_64|R_MIPS_REL32 case
if (ELF64_R_TYPE2(rel->r_info) != R_MIPS_64 ||
ELF64_R_TYPE3(rel->r_info) != R_MIPS_NONE) {
DL_ERR("Unexpected compound relocation type:%d type2:%d type3:%d @ %p (%zu)",
type, (unsigned)ELF64_R_TYPE2(rel->r_info),
(unsigned)ELF64_R_TYPE3(rel->r_info), rel, idx);
return -1;
}
#endif
count_relocation(kRelocAbsolute);
MARK(rel->r_offset);
TRACE_TYPE(RELO, "RELO REL32 %08zx <- %08zx %s", static_cast<size_t>(reloc),
static_cast<size_t>(sym_addr), sym_name ? sym_name : "*SECTIONHDR*");
if (s) {
*reinterpret_cast<ElfW(Addr)*>(reloc) += sym_addr;
} else {
*reinterpret_cast<ElfW(Addr)*>(reloc) += si->base;
}
break;
#endif
#if defined(__arm__)
case R_ARM_RELATIVE:
#elif defined(__i386__)
case R_386_RELATIVE:
#endif
count_relocation(kRelocRelative);
MARK(rel->r_offset);
if (sym) {
DL_ERR("odd RELATIVE form...");
return -1;
}
TRACE_TYPE(RELO, "RELO RELATIVE %p <- +%p",
reinterpret_cast<void*>(reloc), reinterpret_cast<void*>(si->base));
*reinterpret_cast<ElfW(Addr)*>(reloc) += si->base;
break;
default:
DL_ERR("unknown reloc type %d @ %p (%zu)", type, rel, idx);
return -1;
}
}
return 0;
}
#endif
// ARC MOD BEGIN
// Add __inject_arc_linker_hooks and nacl_irt_open_resource_invalid.
static int nacl_irt_open_resource_invalid(const char* name, int* fd) {
DL_ERR("We must not call __nacl_irt_open_resource after "
"__inject_arc_linker_hooks: name=%s", name);
exit(1);
}
void __inject_arc_linker_hooks(__arc_linker_hooks* hooks) {
// TODO(crbug.com/427212): Stop using the injected functions for
// non-NDK shared objects loaded by dlopen.
if (g_resolve_symbol) {
DL_ERR("The linker hooks are already installed.");
exit(-1);
}
if (!hooks->nacl_irt_close ||
!hooks->nacl_irt_mmap ||
!hooks->nacl_irt_munmap ||
!hooks->nacl_irt_open ||
!hooks->nacl_irt_read ||
!hooks->nacl_irt_write ||
!hooks->nacl_irt_fstat ||
!hooks->resolve_symbol) {
DL_ERR("All fields in hooks must be filled.");
exit(-1);
}
g_resolve_symbol = hooks->resolve_symbol;
g_is_statically_linked = hooks->is_statically_linked;
__nacl_irt_close = hooks->nacl_irt_close;
__nacl_irt_mmap = hooks->nacl_irt_mmap;
__nacl_irt_munmap = hooks->nacl_irt_munmap;
__nacl_irt_open = hooks->nacl_irt_open;
__nacl_irt_read = hooks->nacl_irt_read;
__nacl_irt_write = hooks->nacl_irt_write;
__nacl_irt_fstat = hooks->nacl_irt_fstat;
// We will not call __nacl_irt_open_resource in the Bionic loader
// after this not to mix NaCl FD with posix_translation FD.
__nacl_irt_open_resource = nacl_irt_open_resource_invalid;
}
// ARC MOD END
#if defined(__mips__)
static bool mips_relocate_got(soinfo* si, soinfo* needed[]) {
ElfW(Addr)** got = si->plt_got;
if (got == NULL) {
return true;
}
unsigned local_gotno = si->mips_local_gotno;
unsigned gotsym = si->mips_gotsym;
unsigned symtabno = si->mips_symtabno;
ElfW(Sym)* symtab = si->symtab;
// got[0] is the address of the lazy resolver function.
// got[1] may be used for a GNU extension.
// Set it to a recognizable address in case someone calls it (should be _rtld_bind_start).
// FIXME: maybe this should be in a separate routine?
if ((si->flags & FLAG_LINKER) == 0) {
size_t g = 0;
got[g++] = reinterpret_cast<ElfW(Addr)*>(0xdeadbeef);
if (reinterpret_cast<intptr_t>(got[g]) < 0) {
got[g++] = reinterpret_cast<ElfW(Addr)*>(0xdeadfeed);
}
// Relocate the local GOT entries.
for (; g < local_gotno; g++) {
got[g] = reinterpret_cast<ElfW(Addr)*>(reinterpret_cast<uintptr_t>(got[g]) + si->load_bias);
}
}
// Now for the global GOT entries...
ElfW(Sym)* sym = symtab + gotsym;
got = si->plt_got + local_gotno;
for (size_t g = gotsym; g < symtabno; g++, sym++, got++) {
// This is an undefined reference... try to locate it.
const char* sym_name = si->strtab + sym->st_name;
soinfo* lsi;
ElfW(Sym)* s = soinfo_do_lookup(si, sym_name, &lsi, needed);
if (s == NULL) {
// We only allow an undefined symbol if this is a weak reference.
s = &symtab[g];
if (ELF_ST_BIND(s->st_info) != STB_WEAK) {
DL_ERR("cannot locate \"%s\"...", sym_name);
return false;
}
*got = 0;
} else {
// FIXME: is this sufficient?
// For reference see NetBSD link loader
// http://cvsweb.netbsd.org/bsdweb.cgi/src/libexec/ld.elf_so/arch/mips/mips_reloc.c?rev=1.53&content-type=text/x-cvsweb-markup
*got = reinterpret_cast<ElfW(Addr)*>(lsi->load_bias + s->st_value);
}
}
return true;
}
#endif
void soinfo::CallArray(const char* array_name __unused, linker_function_t* functions, size_t count, bool reverse) {
if (functions == NULL) {
return;
}
TRACE("[ Calling %s (size %zd) @ %p for '%s' ]", array_name, count, functions, name);
int begin = reverse ? (count - 1) : 0;
int end = reverse ? -1 : count;
int step = reverse ? -1 : 1;
for (int i = begin; i != end; i += step) {
TRACE("[ %s[%d] == %p ]", array_name, i, functions[i]);
// ARC MOD BEGIN
// The loader passes __nacl_irt_query to the main executable
// using the function in init_array of libc.so. The loader
// does this only for the function immediately after the magic
// number. Currently, init_array is used only on ARM. We use
// .init in other platforms. See bionic/linker/linker.h for
// why we need to pass __nacl_irt_query in this way.
if (!reverse && functions[i] == NEXT_CTOR_FUNC_NEEDS_IRT_QUERY_MARKER) {
TRACE("[ Calling func @ 0x%08x with __nacl_irt_query]\n",
(unsigned)functions[i + 1]);
((void (*)(__nacl_irt_query_fn_t))functions[++i])(__nacl_irt_query);
} else
// ARC MOD END
CallFunction("function", functions[i]);
}
TRACE("[ Done calling %s for '%s' ]", array_name, name);
}
void soinfo::CallFunction(const char* function_name __unused, linker_function_t function) {
if (function == NULL || reinterpret_cast<uintptr_t>(function) == static_cast<uintptr_t>(-1)) {
return;
}
TRACE("[ Calling %s @ %p for '%s' ]", function_name, function, name);
function();
TRACE("[ Done calling %s @ %p for '%s' ]", function_name, function, name);
// The function may have called dlopen(3) or dlclose(3), so we need to ensure our data structures
// are still writable. This happens with our debug malloc (see http://b/7941716).
protect_data(PROT_READ | PROT_WRITE);
}
void soinfo::CallPreInitConstructors() {
// DT_PREINIT_ARRAY functions are called before any other constructors for executables,
// but ignored in a shared library.
CallArray("DT_PREINIT_ARRAY", preinit_array, preinit_array_count, false);
}
void soinfo::CallConstructors() {
if (constructors_called) {
return;
}
// We set constructors_called before actually calling the constructors, otherwise it doesn't
// protect against recursive constructor calls. One simple example of constructor recursion
// is the libc debug malloc, which is implemented in libc_malloc_debug_leak.so:
// 1. The program depends on libc, so libc's constructor is called here.
// 2. The libc constructor calls dlopen() to load libc_malloc_debug_leak.so.
// 3. dlopen() calls the constructors on the newly created
// soinfo for libc_malloc_debug_leak.so.
// 4. The debug .so depends on libc, so CallConstructors is
// called again with the libc soinfo. If it doesn't trigger the early-
// out above, the libc constructor will be called again (recursively!).
constructors_called = true;
// ARC MOD BEGIN
// Print the elapsed time for calling init functions.
ScopedElapsedTimePrinter<__LINE__> printer("Called constructors for", name);
// ARC MOD END
if ((flags & FLAG_EXE) == 0 && preinit_array != NULL) {
// The GNU dynamic linker silently ignores these, but we warn the developer.
PRINT("\"%s\": ignoring %zd-entry DT_PREINIT_ARRAY in shared library!",
name, preinit_array_count);
}
get_children().for_each([] (soinfo* si) {
// ARC MOD BEGIN
// We may not be able to find DT_NEEDED specified by NDK's
// shared objects, because ARC links a lot of libraries to
// the main binary. For example, NDK apps may have DT_NEEDED
// which expects libz.so exists, but ARC does not have
// libz.so. We build libz.a and link it to the main binary.
//
// For such DT_NEEDED in NDK objects, find_loaded_library()
// may return NULL. We must not try calling CallConstructors()
// for them.
//
// TODO(crbug.com/414569): L-rebase: Is this necessary or sufficient ?
#if defined(HAVE_ARC)
if (si)
#endif
// ARC MOD END
si->CallConstructors();
});
TRACE("\"%s\": calling constructors", name);
// DT_INIT should be called before DT_INIT_ARRAY if both are present.
// ARC MOD BEGIN
#if defined(HAVE_ARC)
// The loader passes __nacl_irt_query to the main executable
// here. See bionic/linker/linker.h for detail.
if (init_func != NULL &&
reinterpret_cast<uintptr_t>(init_func) != static_cast<uintptr_t>(-1)) {
// Show trace logs as CallFunction does.
TRACE("[ Calling DT_INIT @ %p for '%s' ]", init_func, name);
init_func(__nacl_irt_query);
TRACE("[ Done calling DT_INIT @ %p for '%s' ]", init_func, name);
protect_data(PROT_READ | PROT_WRITE);
}
#else
// ARC MOD END
CallFunction("DT_INIT", init_func);
// ARC MOD BEGIN
#endif
// ARC MOD END
CallArray("DT_INIT_ARRAY", init_array, init_array_count, false);
}
void soinfo::CallDestructors() {
TRACE("\"%s\": calling destructors", name);
// DT_FINI_ARRAY must be parsed in reverse order.
CallArray("DT_FINI_ARRAY", fini_array, fini_array_count, true);
// DT_FINI should be called after DT_FINI_ARRAY if both are present.
CallFunction("DT_FINI", fini_func);
// This is needed on second call to dlopen
// after library has been unloaded with RTLD_NODELETE
constructors_called = false;
}
void soinfo::add_child(soinfo* child) {
if ((this->flags & FLAG_NEW_SOINFO) == 0) {
return;
}
this->children.push_front(child);
child->parents.push_front(this);
}
void soinfo::remove_all_links() {
if ((this->flags & FLAG_NEW_SOINFO) == 0) {
return;
}
// 1. Untie connected soinfos from 'this'.
children.for_each([&] (soinfo* child) {
child->parents.remove_if([&] (const soinfo* parent) {
return parent == this;
});
});
parents.for_each([&] (soinfo* parent) {
parent->children.for_each([&] (const soinfo* child) {
return child == this;
});
});
// 2. Once everything untied - clear local lists.
parents.clear();
children.clear();
}
void soinfo::set_st_dev(dev_t dev) {
if ((this->flags & FLAG_NEW_SOINFO) == 0) {
return;
}
st_dev = dev;
}
void soinfo::set_st_ino(ino_t ino) {
if ((this->flags & FLAG_NEW_SOINFO) == 0) {
return;
}
st_ino = ino;
}
dev_t soinfo::get_st_dev() {
if ((this->flags & FLAG_NEW_SOINFO) == 0) {
return 0;
}
return st_dev;
};
ino_t soinfo::get_st_ino() {
if ((this->flags & FLAG_NEW_SOINFO) == 0) {
return 0;
}
return st_ino;
}
// This is a return on get_children() in case
// 'this->flags' does not have FLAG_NEW_SOINFO set.
static soinfo::soinfo_list_t g_empty_list;
soinfo::soinfo_list_t& soinfo::get_children() {
if ((this->flags & FLAG_NEW_SOINFO) == 0) {
return g_empty_list;
}
return this->children;
}
/* Force any of the closed stdin, stdout and stderr to be associated with
/dev/null. */
static int nullify_closed_stdio() {
int dev_null, i, status;
int return_value = 0;
dev_null = TEMP_FAILURE_RETRY(open("/dev/null", O_RDWR));
if (dev_null < 0) {
DL_ERR("cannot open /dev/null: %s", strerror(errno));
return -1;
}
TRACE("[ Opened /dev/null file-descriptor=%d]", dev_null);
/* If any of the stdio file descriptors is valid and not associated
with /dev/null, dup /dev/null to it. */
for (i = 0; i < 3; i++) {
/* If it is /dev/null already, we are done. */
if (i == dev_null) {
continue;
}
TRACE("[ Nullifying stdio file descriptor %d]", i);
status = TEMP_FAILURE_RETRY(fcntl(i, F_GETFL));
/* If file is opened, we are good. */
if (status != -1) {
continue;
}
/* The only error we allow is that the file descriptor does not
exist, in which case we dup /dev/null to it. */
if (errno != EBADF) {
DL_ERR("fcntl failed: %s", strerror(errno));
return_value = -1;
continue;
}
/* Try dupping /dev/null to this stdio file descriptor and
repeat if there is a signal. Note that any errors in closing
the stdio descriptor are lost. */
status = TEMP_FAILURE_RETRY(dup2(dev_null, i));
if (status < 0) {
DL_ERR("dup2 failed: %s", strerror(errno));
return_value = -1;
continue;
}
}
/* If /dev/null is not one of the stdio file descriptors, close it. */
if (dev_null > 2) {
TRACE("[ Closing /dev/null file-descriptor=%d]", dev_null);
status = TEMP_FAILURE_RETRY(close(dev_null));
if (status == -1) {
DL_ERR("close failed: %s", strerror(errno));
return_value = -1;
}
}
return return_value;
}
static bool soinfo_link_image(soinfo* si, const android_dlextinfo* extinfo) {
/* "base" might wrap around UINT32_MAX. */
ElfW(Addr) base = si->load_bias;
const ElfW(Phdr)* phdr = si->phdr;
int phnum = si->phnum;
bool relocating_linker = (si->flags & FLAG_LINKER) != 0;
/* We can't debug anything until the linker is relocated */
if (!relocating_linker) {
INFO("[ linking %s ]", si->name);
DEBUG("si->base = %p si->flags = 0x%08x", reinterpret_cast<void*>(si->base), si->flags);
}
/* Extract dynamic section */
size_t dynamic_count;
ElfW(Word) dynamic_flags;
phdr_table_get_dynamic_section(phdr, phnum, base, &si->dynamic,
&dynamic_count, &dynamic_flags);
if (si->dynamic == NULL) {
if (!relocating_linker) {
DL_ERR("missing PT_DYNAMIC in \"%s\"", si->name);
}
return false;
} else {
if (!relocating_linker) {
DEBUG("dynamic = %p", si->dynamic);
}
}
// ARC MOD BEGIN UPSTREAM bionic-set-l_ld-in-main-binary
if (si->flags & FLAG_EXE)
si->link_map_head.l_ld = reinterpret_cast<ElfW(Dyn)*>(si->dynamic);
// ARC MOD END UPSTREAM
#if defined(__arm__)
(void) phdr_table_get_arm_exidx(phdr, phnum, base,
&si->ARM_exidx, &si->ARM_exidx_count);
#endif
// Extract useful information from dynamic section.
uint32_t needed_count = 0;
for (ElfW(Dyn)* d = si->dynamic; d->d_tag != DT_NULL; ++d) {
DEBUG("d = %p, d[0](tag) = %p d[1](val) = %p",
d, reinterpret_cast<void*>(d->d_tag), reinterpret_cast<void*>(d->d_un.d_val));
switch (d->d_tag) {
case DT_HASH:
si->nbucket = reinterpret_cast<uint32_t*>(base + d->d_un.d_ptr)[0];
si->nchain = reinterpret_cast<uint32_t*>(base + d->d_un.d_ptr)[1];
si->bucket = reinterpret_cast<uint32_t*>(base + d->d_un.d_ptr + 8);
si->chain = reinterpret_cast<uint32_t*>(base + d->d_un.d_ptr + 8 + si->nbucket * 4);
break;
case DT_STRTAB:
si->strtab = reinterpret_cast<const char*>(base + d->d_un.d_ptr);
break;
case DT_SYMTAB:
si->symtab = reinterpret_cast<ElfW(Sym)*>(base + d->d_un.d_ptr);
break;
#if !defined(__LP64__)
case DT_PLTREL:
// ARC MOD BEGIN
// NaCl x86-64 uses ELF64 so we should expect Elf64_Rela.
#if defined(__native_client__) && defined(__x86_64__)
if (d->d_un.d_val != DT_RELA) {
DL_ERR("unsupported DT_REL in \"%s\"", si->name);
return false;
}
#else
// ARC MOD END
if (d->d_un.d_val != DT_REL) {
DL_ERR("unsupported DT_RELA in \"%s\"", si->name);
return false;
}
// ARC MOD BEGIN
#endif
// ARC MOD END
break;
#endif
case DT_JMPREL:
#if defined(USE_RELA)
si->plt_rela = reinterpret_cast<ElfW(Rela)*>(base + d->d_un.d_ptr);
#else
si->plt_rel = reinterpret_cast<ElfW(Rel)*>(base + d->d_un.d_ptr);
#endif
break;
case DT_PLTRELSZ:
#if defined(USE_RELA)
si->plt_rela_count = d->d_un.d_val / sizeof(ElfW(Rela));
#else
si->plt_rel_count = d->d_un.d_val / sizeof(ElfW(Rel));
#endif
break;
#if defined(__mips__)
case DT_PLTGOT:
// Used by mips and mips64.
si->plt_got = reinterpret_cast<ElfW(Addr)**>(base + d->d_un.d_ptr);
break;
#endif
case DT_DEBUG:
// Set the DT_DEBUG entry to the address of _r_debug for GDB
// if the dynamic table is writable
// FIXME: not working currently for N64
// The flags for the LOAD and DYNAMIC program headers do not agree.
// The LOAD section containng the dynamic table has been mapped as
// read-only, but the DYNAMIC header claims it is writable.
#if !(defined(__mips__) && defined(__LP64__))
if ((dynamic_flags & PF_W) != 0) {
d->d_un.d_val = reinterpret_cast<uintptr_t>(&_r_debug);
}
break;
#endif
#if defined(USE_RELA)
case DT_RELA:
si->rela = reinterpret_cast<ElfW(Rela)*>(base + d->d_un.d_ptr);
break;
case DT_RELASZ:
si->rela_count = d->d_un.d_val / sizeof(ElfW(Rela));
break;
case DT_REL:
DL_ERR("unsupported DT_REL in \"%s\"", si->name);
return false;
case DT_RELSZ:
DL_ERR("unsupported DT_RELSZ in \"%s\"", si->name);
return false;
#else
case DT_REL:
si->rel = reinterpret_cast<ElfW(Rel)*>(base + d->d_un.d_ptr);
break;
case DT_RELSZ:
si->rel_count = d->d_un.d_val / sizeof(ElfW(Rel));
break;
case DT_RELA:
DL_ERR("unsupported DT_RELA in \"%s\"", si->name);
return false;
#endif
case DT_INIT:
// ARC MOD BEGIN
// The type of si->init_func was changed. See
// bionic/linker/linker.h for detail.
#if defined(HAVE_ARC)
si->init_func = (void (*)(__nacl_irt_query_fn_t))(base + d->d_un.d_ptr);
#else
// ARC MOD END
si->init_func = reinterpret_cast<linker_function_t>(base + d->d_un.d_ptr);
// ARC MOD BEGIN
#endif
// ARC MOD END
DEBUG("%s constructors (DT_INIT) found at %p", si->name, si->init_func);
break;
case DT_FINI:
si->fini_func = reinterpret_cast<linker_function_t>(base + d->d_un.d_ptr);
DEBUG("%s destructors (DT_FINI) found at %p", si->name, si->fini_func);
break;
case DT_INIT_ARRAY:
si->init_array = reinterpret_cast<linker_function_t*>(base + d->d_un.d_ptr);
DEBUG("%s constructors (DT_INIT_ARRAY) found at %p", si->name, si->init_array);
break;
case DT_INIT_ARRAYSZ:
// ARC MOD BEGIN
// Use sizeof(void*) instead of ElfW(Addr) which is Elf64_Addr.
// As x86-64 NaCl uses ELF64, we need to use 64bit integers to
// access addresses in ELF structures. However, for init_array,
// fini_array, and preinit_array, NaCl uses 32bit integers to
// store addresses.
si->init_array_count = ((unsigned)d->d_un.d_val) / sizeof(void*);
// ARC MOD END
break;
case DT_FINI_ARRAY:
si->fini_array = reinterpret_cast<linker_function_t*>(base + d->d_un.d_ptr);
DEBUG("%s destructors (DT_FINI_ARRAY) found at %p", si->name, si->fini_array);
break;
case DT_FINI_ARRAYSZ:
// ARC MOD BEGIN
// See the comment for DT_INIT_ARRAYSZ.
si->fini_array_count = ((unsigned)d->d_un.d_val) / sizeof(void*);
// ARC MOD END
break;
case DT_PREINIT_ARRAY:
si->preinit_array = reinterpret_cast<linker_function_t*>(base + d->d_un.d_ptr);
DEBUG("%s constructors (DT_PREINIT_ARRAY) found at %p", si->name, si->preinit_array);
break;
case DT_PREINIT_ARRAYSZ:
// ARC MOD BEGIN
// See the comment for DT_INIT_ARRAYSZ.
// si->preinit_array_count = ((unsigned)d->d_un.d_val) / sizeof(ElfW(Addr));
si->preinit_array_count = ((unsigned)d->d_un.d_val) / sizeof(void*);
// ARC MOD END
break;
case DT_TEXTREL:
#if defined(__LP64__)
DL_ERR("text relocations (DT_TEXTREL) found in 64-bit ELF file \"%s\"", si->name);
return false;
#else
si->has_text_relocations = true;
break;
#endif
case DT_SYMBOLIC:
si->has_DT_SYMBOLIC = true;
break;
case DT_NEEDED:
++needed_count;
break;
case DT_FLAGS:
if (d->d_un.d_val & DF_TEXTREL) {
#if defined(__LP64__)
DL_ERR("text relocations (DF_TEXTREL) found in 64-bit ELF file \"%s\"", si->name);
return false;
#else
si->has_text_relocations = true;
#endif
}
if (d->d_un.d_val & DF_SYMBOLIC) {
si->has_DT_SYMBOLIC = true;
}
break;
#if defined(__mips__)
case DT_STRSZ:
case DT_SYMENT:
case DT_RELENT:
break;
case DT_MIPS_RLD_MAP:
// Set the DT_MIPS_RLD_MAP entry to the address of _r_debug for GDB.
{
r_debug** dp = reinterpret_cast<r_debug**>(base + d->d_un.d_ptr);
*dp = &_r_debug;
}
break;
case DT_MIPS_RLD_VERSION:
case DT_MIPS_FLAGS:
case DT_MIPS_BASE_ADDRESS:
case DT_MIPS_UNREFEXTNO:
break;
case DT_MIPS_SYMTABNO:
si->mips_symtabno = d->d_un.d_val;
break;
case DT_MIPS_LOCAL_GOTNO:
si->mips_local_gotno = d->d_un.d_val;
break;
case DT_MIPS_GOTSYM:
si->mips_gotsym = d->d_un.d_val;
break;
#endif
default:
DEBUG("Unused DT entry: type %p arg %p",
reinterpret_cast<void*>(d->d_tag), reinterpret_cast<void*>(d->d_un.d_val));
break;
}
}
DEBUG("si->base = %p, si->strtab = %p, si->symtab = %p",
reinterpret_cast<void*>(si->base), si->strtab, si->symtab);
// Sanity checks.
if (relocating_linker && needed_count != 0) {
DL_ERR("linker cannot have DT_NEEDED dependencies on other libraries");
return false;
}
if (si->nbucket == 0) {
DL_ERR("empty/missing DT_HASH in \"%s\" (built with --hash-style=gnu?)", si->name);
return false;
}
if (si->strtab == 0) {
DL_ERR("empty/missing DT_STRTAB in \"%s\"", si->name);
return false;
}
if (si->symtab == 0) {
DL_ERR("empty/missing DT_SYMTAB in \"%s\"", si->name);
return false;
}
// If this is the main executable, then load all of the libraries from LD_PRELOAD now.
if (si->flags & FLAG_EXE) {
memset(g_ld_preloads, 0, sizeof(g_ld_preloads));
size_t preload_count = 0;
for (size_t i = 0; g_ld_preload_names[i] != NULL; i++) {
soinfo* lsi = find_library(g_ld_preload_names[i], 0, NULL);
if (lsi != NULL) {
g_ld_preloads[preload_count++] = lsi;
} else {
// As with glibc, failure to load an LD_PRELOAD library is just a warning.
DL_WARN("could not load library \"%s\" from LD_PRELOAD for \"%s\"; caused by %s",
g_ld_preload_names[i], si->name, linker_get_error_buffer());
}
}
}
soinfo** needed = reinterpret_cast<soinfo**>(alloca((1 + needed_count) * sizeof(soinfo*)));
soinfo** pneeded = needed;
for (ElfW(Dyn)* d = si->dynamic; d->d_tag != DT_NULL; ++d) {
if (d->d_tag == DT_NEEDED) {
const char* library_name = si->strtab + d->d_un.d_val;
DEBUG("%s needs %s", si->name, library_name);
// ARC MOD BEGIN
// We may not be able to find DT_NEEDED specified by NDK's
// shared objects, because ARC links a lot of libraries to
// the main binary. For example, NDK apps may have
// DT_NEEDED which expects libz.so exists, but ARC does
// not have libz.so. We build libz.a and link it to the
// main binary.
#if defined(HAVE_ARC)
if (g_is_statically_linked && g_is_statically_linked(library_name))
continue;
#endif
// ARC MOD END
soinfo* lsi = find_library(library_name, 0, NULL);
if (lsi == NULL) {
strlcpy(tmp_err_buf, linker_get_error_buffer(), sizeof(tmp_err_buf));
DL_ERR("could not load library \"%s\" needed by \"%s\"; caused by %s",
library_name, si->name, tmp_err_buf);
return false;
}
si->add_child(lsi);
*pneeded++ = lsi;
}
}
// ARC MOD BEGIN
// Valgrind injects vgpreload_*.so and they require a few symbols
// in libc.so. However, they do not have DT_NEEDED entry. With
// glibc loader's semantics, symbols will be properly resolved
// from libc.so but with Bionic, we need an explicit DT_NEEDED
// entry for libc.so.
#if defined(RUNNING_ON_VALGRIND)
if (!strcmp(si->name, "vgpreload_core-x86-linux.so") ||
!strcmp(si->name, "vgpreload_memcheck-x86-linux.so"))
*pneeded++ = find_library("libc.so", 0, NULL);
#endif
// ARC MOD END
*pneeded = NULL;
#if !defined(__LP64__)
if (si->has_text_relocations) {
// Make segments writable to allow text relocations to work properly. We will later call
// phdr_table_protect_segments() after all of them are applied and all constructors are run.
DL_WARN("%s has text relocations. This is wasting memory and prevents "
"security hardening. Please fix.", si->name);
if (phdr_table_unprotect_segments(si->phdr, si->phnum, si->load_bias) < 0) {
DL_ERR("can't unprotect loadable segments for \"%s\": %s",
si->name, strerror(errno));
return false;
}
}
#endif
#if defined(USE_RELA)
if (si->plt_rela != NULL) {
// ARC MOD BEGIN
// Print the elapsed time for relocating symbols.
ScopedElapsedTimePrinter<__LINE__> printer("Relocated plt symbols for", si->name);
// ARC MOD END
DEBUG("[ relocating %s plt ]\n", si->name);
if (soinfo_relocate(si, si->plt_rela, si->plt_rela_count, needed)) {
return false;
}
}
if (si->rela != NULL) {
// ARC MOD BEGIN
// Print the elapsed time for relocating symbols.
ScopedElapsedTimePrinter<__LINE__> printer("Relocated symbols for", si->name);
// ARC MOD END
DEBUG("[ relocating %s ]\n", si->name);
if (soinfo_relocate(si, si->rela, si->rela_count, needed)) {
return false;
}
}
#else
if (si->plt_rel != NULL) {
// ARC MOD BEGIN
// Print the elapsed time for relocating symbols.
ScopedElapsedTimePrinter<__LINE__> printer("Relocated plt symbols for", si->name);
// ARC MOD END
DEBUG("[ relocating %s plt ]", si->name);
if (soinfo_relocate(si, si->plt_rel, si->plt_rel_count, needed)) {
return false;
}
}
if (si->rel != NULL) {
// ARC MOD BEGIN
// Print the elapsed time for relocating symbols.
ScopedElapsedTimePrinter<__LINE__> printer("Relocated symbols for", si->name);
// ARC MOD END
DEBUG("[ relocating %s ]", si->name);
if (soinfo_relocate(si, si->rel, si->rel_count, needed)) {
return false;
}
}
#endif
#if defined(__mips__)
if (!mips_relocate_got(si, needed)) {
return false;
}
#endif
si->flags |= FLAG_LINKED;
DEBUG("[ finished linking %s ]", si->name);
#if !defined(__LP64__)
if (si->has_text_relocations) {
// All relocations are done, we can protect our segments back to read-only.
if (phdr_table_protect_segments(si->phdr, si->phnum, si->load_bias) < 0) {
DL_ERR("can't protect segments for \"%s\": %s",
si->name, strerror(errno));
return false;
}
}
#endif
/* We can also turn on GNU RELRO protection */
if (phdr_table_protect_gnu_relro(si->phdr, si->phnum, si->load_bias) < 0) {
DL_ERR("can't enable GNU RELRO protection for \"%s\": %s",
si->name, strerror(errno));
return false;
}
/* Handle serializing/sharing the RELRO segment */
if (extinfo && (extinfo->flags & ANDROID_DLEXT_WRITE_RELRO)) {
if (phdr_table_serialize_gnu_relro(si->phdr, si->phnum, si->load_bias,
extinfo->relro_fd) < 0) {
DL_ERR("failed serializing GNU RELRO section for \"%s\": %s",
si->name, strerror(errno));
return false;
}
} else if (extinfo && (extinfo->flags & ANDROID_DLEXT_USE_RELRO)) {
if (phdr_table_map_gnu_relro(si->phdr, si->phnum, si->load_bias,
extinfo->relro_fd) < 0) {
DL_ERR("failed mapping GNU RELRO section for \"%s\": %s",
si->name, strerror(errno));
return false;
}
}
notify_gdb_of_load(si);
return true;
}
// ARC MOD BEGIN
// add_vdso() is not called in NaCl and Bare Metal.
#if !defined(HAVE_ARC)
// ARC MOD END
/*
* This function add vdso to internal dso list.
* It helps to stack unwinding through signal handlers.
* Also, it makes bionic more like glibc.
*/
static void add_vdso(KernelArgumentBlock& args __unused) {
#if defined(AT_SYSINFO_EHDR)
ElfW(Ehdr)* ehdr_vdso = reinterpret_cast<ElfW(Ehdr)*>(args.getauxval(AT_SYSINFO_EHDR));
if (ehdr_vdso == NULL) {
return;
}
soinfo* si = soinfo_alloc("[vdso]", NULL);
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);
soinfo_link_image(si, NULL);
#endif
}
// ARC MOD BEGIN
#endif
// ARC MOD END
/*
* This is linker soinfo for GDB. See details below.
*/
static soinfo linker_soinfo_for_gdb;
// ARC MOD BEGIN
// We disable debug info related stuff. On NaCl, gdb will interact
// with the loader in the host so we need to do nothing for it.
#if !defined(HAVE_ARC)
// ARC MOD END
/* 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.
* Don't use soinfo_alloc(), because the linker shouldn't
* be on the soinfo list.
*/
static void init_linker_info_for_gdb(ElfW(Addr) linker_base) {
#if defined(__LP64__)
strlcpy(linker_soinfo_for_gdb.name, "/system/bin/linker64", sizeof(linker_soinfo_for_gdb.name));
#else
strlcpy(linker_soinfo_for_gdb.name, "/system/bin/linker", sizeof(linker_soinfo_for_gdb.name));
#endif
linker_soinfo_for_gdb.flags = FLAG_NEW_SOINFO;
linker_soinfo_for_gdb.base = linker_base;
/*
* Set the dynamic field in the link map otherwise gdb will complain with
* the following:
* warning: .dynamic section for "/system/bin/linker" is not at the
* expected address (wrong library or version mismatch?)
*/
ElfW(Ehdr)* elf_hdr = reinterpret_cast<ElfW(Ehdr)*>(linker_base);
ElfW(Phdr)* phdr = reinterpret_cast<ElfW(Phdr)*>(linker_base + elf_hdr->e_phoff);
phdr_table_get_dynamic_section(phdr, elf_hdr->e_phnum, linker_base,
&linker_soinfo_for_gdb.dynamic, NULL, NULL);
insert_soinfo_into_debug_map(&linker_soinfo_for_gdb);
}
// ARC MOD BEGIN
#endif // !__native_client__
// ARC MOD END
// ARC MOD BEGIN
// Temporary support of GDB.
#if defined(BARE_METAL_BIONIC)
static const char kBareMetalGdbDir[] = "/tmp/bare_metal_gdb/";
// This function is called in very early stage of process initialization to
// wait for GDB to attach to this process and install necessary breakpoints.
static void maybe_wait_gdb_attach() {
// First check existence of a lock directory. Return if it does not exist.
// Note that it's safe to call open syscall here even under Bare Metal's
// seccomp sandbox; it just returns EPERM instead of killing the process.
int fd = TEMP_FAILURE_RETRY(
syscall(__NR_open, kBareMetalGdbDir, O_RDONLY | O_DIRECTORY));
if (fd < 0) {
return;
}
syscall(__NR_close, fd);
// Existence of the lock directory indicates that the user wants to debug
// this process. Touch a PID marker file under the directory, print PID to
// stderr, and wait for the file to be removed.
// Note that it's safe to call getpid here because successful open syscall
// above means seccomp sandbox is disabled.
int pid = TEMP_FAILURE_RETRY(syscall(__NR_getpid));
if (pid < 0) {
DL_ERR("tried communicating with gdb, but getpid failed.\n");
exit(-1);
}
char lock_file[64];
__libc_format_buffer(
lock_file, sizeof(lock_file), "%s%d", kBareMetalGdbDir, pid);
fd = TEMP_FAILURE_RETRY(
syscall(__NR_open, lock_file, O_WRONLY | O_CREAT, 0755));
if (fd < 0) {
DL_ERR("tried communicating with gdb, but failed to touch a lock file.\n");
exit(-1);
}
syscall(__NR_close, fd);
// Notify that we are ready to be attached by gdb.
// Note that this message is hard-coded in build scripts.
__libc_format_fd(2, "linker: waiting for gdb (%d)\n", pid);
for (;;) {
fd = TEMP_FAILURE_RETRY(syscall(__NR_open, lock_file, O_RDONLY));
if (fd < 0) {
if (errno != ENOENT) {
DL_ERR("tried communicating with gdb, but failed to watch "
"a lock file: %s.\n",
strerror(errno));
exit(-1);
}
break;
}
syscall(__NR_close, fd);
}
}
#endif // BARE_METAL_BIONIC
// ARC MOD END
/*
* This code is called after the linker has linked itself and
* fixed it's own GOT. It is safe to make references to externs
* and other non-local data at this point.
*/
static ElfW(Addr) __linker_init_post_relocation(KernelArgumentBlock& args, ElfW(Addr) linker_base) {
/* NOTE: we store the args pointer on a special location
* of the temporary TLS area in order to pass it to
* the C Library's runtime initializer.
*
* The initializer must clear the slot and reset the TLS
* to point to a different location to ensure that no other
* shared library constructor can access it.
*/
__libc_init_tls(args);
// ARC MOD BEGIN
// Place a pointer to __get_tls in a fixed address on Bare Metal
// i686. Though this depends on Linux kernel's ASLR, it would be OK
// as Bare Metal i686 with glibc is not a production target.
// See also bionic/libc/include/private/get_tls_for_art.h.
//
// Also note this should be done after __libc_init_tls. Otherwise,
// updating errno will cause a crash.
// TODO(crbug.com/465216): Remove this after the newlib switch.
#if defined(BARE_METAL_BIONIC) && defined(__i386__)
if (!mprotect(reinterpret_cast<void*>(POINTER_TO_GET_TLS_FUNC_ON_BMM_I386),
PAGE_SIZE, PROT_READ)) {
// The mprotect call above must fail. If the mprotect call
// succeeds, this means the page is already in use.
DL_ERR("The fixed address for ART is already in use");
exit(1);
}
get_tls_fn_t* get_tls_ptr = static_cast<get_tls_fn_t*>(
mmap(reinterpret_cast<void*>(POINTER_TO_GET_TLS_FUNC_ON_BMM_I386),
PAGE_SIZE,
PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED,
-1, 0));
if (get_tls_ptr == MAP_FAILED) {
DL_ERR("Failed to mmap a fixed address for ART");
exit(1);
}
*get_tls_ptr = &__get_tls;
// Make it read-only, just in case.
if (mprotect(get_tls_ptr, PAGE_SIZE, PROT_READ)) {
DL_ERR("Failed to mprotect the fixed address for ART");
exit(1);
}
#endif
// ARC MOD END
// ARC MOD BEGIN
// Temporary support of GDB.
#if defined(BARE_METAL_BIONIC)
// Wait for gdb attaching to this process.
// If the main binary is /lib/main.nexe, the Bionic loader is
// launched by nacl_helper and not by nonsfi_loader, so we should
// wait for GDB. Note that run_unittest.py does not rely on
// /tmp/bare_metal_gdb.
// TODO(crbug.com/354290): Remove this hack. Use __nacl_irt_open and
// __nacl_irt_close instead of the direct syscalls when we add more
// restrictions to the syscall sandbox.
if (args.argc == 1 && !strcmp(args.argv[0], "/lib/main.nexe"))
maybe_wait_gdb_attach();
#endif // BARE_METAL_BIONIC
// ARC MOD END
#if TIMING
struct timeval t0, t1;
gettimeofday(&t0, 0);
#endif
// Initialize environment functions, and get to the ELF aux vectors table.
linker_env_init(args);