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darling/ld-mac.cc
Shinichiro Hamaji 638e39e62f Initialize MachOLoader::last_addr_
2011-04-08 01:26:31 +09:00

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// Copyright 2011 Shinichiro Hamaji. All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
//
// 1. Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//
// 2. 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 Shinichiro Hamaji ``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 Shinichiro Hamaji 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.
// A Mach-O loader for linux.
#include <assert.h>
#include <dlfcn.h>
#include <err.h>
#include <errno.h>
#include <execinfo.h>
#include <fcntl.h>
#include <limits.h>
#include <memory>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <time.h>
#include <ucontext.h>
#include <algorithm>
#include <iostream>
#include <map>
#include <set>
#include <string>
#include <vector>
#include "env_flags.h"
#include "fat.h"
#include "log.h"
#include "mach-o.h"
using namespace std;
DEFINE_bool(TRACE_FUNCTIONS, false, "Show calling functions");
DEFINE_bool(PRINT_TIME, false, "Print time spent in this loader");
class MachO;
static map<string, string> g_rename;
static vector<const char*> g_bound_names;
static set<string> g_no_trampoline;
class FileMap {
public:
void add(const MachO& mach, uintptr_t slide, uintptr_t base) {
SymbolMap* symbol_map = new SymbolMap();
symbol_map->filename = mach.filename();
symbol_map->base = base;
if (!maps_.insert(make_pair(base, symbol_map)).second) {
err(1, "dupicated base addr: %p in %s",
(void*)base, mach.filename().c_str());
}
for (size_t i = 0; i < mach.symbols().size(); i++) {
MachO::Symbol sym = mach.symbols()[i];
if (sym.name.empty() || sym.name[0] != '_')
continue;
sym.addr += slide;
if (sym.addr < base)
continue;
symbol_map->symbols.insert(make_pair(sym.addr, sym.name.substr(1)));
}
}
void addWatchDog(uintptr_t addr) {
bool r = maps_.insert(make_pair(addr, (SymbolMap*)NULL)).second;
CHECK(r);
}
const char* dumpSymbol(void* p) {
uintptr_t addr = reinterpret_cast<uintptr_t>(p);
map<uintptr_t, SymbolMap*>::const_iterator found = maps_.upper_bound(addr);
if (found == maps_.begin() || found == maps_.end()) {
return NULL;
}
--found;
return dumpSymbolFromMap(*found->second, addr);
}
private:
struct SymbolMap {
string filename;
map<uintptr_t, string> symbols;
uintptr_t base;
};
const char* dumpSymbolFromMap(const SymbolMap& symbol_map, uintptr_t addr) {
uintptr_t file_offset = addr - symbol_map.base;
// Use lower_bound as PC may be in just after call.
map<uintptr_t, string>::const_iterator found =
symbol_map.symbols.lower_bound(addr);
if (found == symbol_map.symbols.begin()) {
snprintf(dumped_stack_frame_buf_, 4095, "%s [%p(%lx)]",
symbol_map.filename.c_str(), (void*)addr, file_offset);
return dumped_stack_frame_buf_;
}
--found;
const char* name = found->second.c_str();
uintptr_t func_offset = addr - found->first;
snprintf(dumped_stack_frame_buf_, 4095, "%s(%s+%lx) [%p(%lx)]",
symbol_map.filename.c_str(), name, func_offset,
(void*)addr, file_offset);
return dumped_stack_frame_buf_;
}
map<uintptr_t, SymbolMap*> maps_;
char dumped_stack_frame_buf_[4096];
};
static FileMap g_file_map;
// We only support x86-64 for now.
static const char* ARCH_NAME = "x86-64";
static char* g_darwin_executable_path;
static clock_t g_start_time;
// TODO(hamaji): Need a static type...
static void* g_loader;
static void initRename() {
#define RENAME(src, dst) g_rename.insert(make_pair(#src, #dst));
#define WRAP(src) RENAME(src, __darwin_ ## src)
#include "rename.tab"
#undef RENAME
#undef WRAP
}
static void initNoTrampoline() {
#define NO_TRAMPOLINE(name) g_no_trampoline.insert(#name);
#include "no_trampoline.tab"
#undef NO_TRAMPOLINE
}
static void undefinedFunction() {
fprintf(stderr, "Undefined function called\n");
abort();
}
static void doNothing() {
}
static bool lookupDyldFunction(const char* name, uint64_t* addr) {
LOG << "lookupDyldFunction: " << name << endl;
*addr = (int64_t)&doNothing;
return true;
}
static uint64_t alignMem(uint64_t p, uint64_t a) {
a--;
return (p + a) & ~a;
}
static void dumpInt(int bound_name_id) {
if (bound_name_id < 0) {
fprintf(stderr, "%d: negative bound function id\n", bound_name_id);
return;
}
if (bound_name_id >= (int)g_bound_names.size()) {
fprintf(stderr, "%d: bound function id overflow\n", bound_name_id);
return;
}
if (!g_bound_names[bound_name_id]) {
fprintf(stderr, "%d: unbound function id\n", bound_name_id);
return;
}
printf("calling %s(%d)\n", g_bound_names[bound_name_id], bound_name_id);
fflush(stdout);
}
template <bool is64>
struct BitsHelpers {
typedef uint64_t intptr;
typedef segment_command_64 mach_segment;
static const vector<mach_segment*>& segments(const MachO& mach) {
return mach.segments64();
}
};
template <>
struct BitsHelpers<false> {
typedef uint32_t intptr;
typedef segment_command mach_segment;
static const vector<mach_segment*>& segments(const MachO& mach) {
return mach.segments();
}
};
template <bool is64>
class MachOLoader {
typedef BitsHelpers<is64> Helpers;
typedef typename Helpers::intptr intptr;
typedef typename Helpers::mach_segment Segment;
public:
MachOLoader()
: last_addr_(0) {
if (FLAGS_TRACE_FUNCTIONS) {
// Push all arguments into stack.
// push %rax
pushTrampolineCode(0x50);
// push %rdi
pushTrampolineCode(0x57);
// push %rsi
pushTrampolineCode(0x56);
// push %rdx
pushTrampolineCode(0x52);
// push %rcx
pushTrampolineCode(0x51);
// push %r8
pushTrampolineCode(0x5041);
// push %r9
pushTrampolineCode(0x5141);
// push %xmm0..%xmm7
for (int i = 0; i < 8; i++) {
// sub $8, %rsp
pushTrampolineCode(0x08ec8348);
// movq %xmmN, (%rsp)
pushTrampolineCode(0xd60f66);
pushTrampolineCode(4 + i * 8);
pushTrampolineCode(0x24);
}
// mov %r10, %rdi
pushTrampolineCode(0xd7894c);
// mov $func, %rdx
pushTrampolineCode(0xba48);
pushTrampolineCode64((unsigned long long)(void*)&dumpInt);
// call *%rdx
pushTrampolineCode(0xd2ff);
// pop %xmm7..%xmm0
for (int i = 7; i >= 0; i--) {
// movq (%rsp), %xmmN
pushTrampolineCode(0x7e0ff3);
pushTrampolineCode(4 + i * 8);
pushTrampolineCode(0x24);
// add $8, %rsp
pushTrampolineCode(0x08c48348);
}
// pop %r9
pushTrampolineCode(0x5941);
// pop %r8
pushTrampolineCode(0x5841);
// pop %rcx
pushTrampolineCode(0x59);
// pop %rdx
pushTrampolineCode(0x5a);
// pop %rsi
pushTrampolineCode(0x5e);
// pop %rdi
pushTrampolineCode(0x5f);
// pop %rax
pushTrampolineCode(0x58);
// ret
pushTrampolineCode(0xc3);
}
}
void loadSegments(const MachO& mach, intptr* slide, intptr* base) {
*base = 0;
--*base;
const vector<Segment*>& segments = Helpers::segments(mach);
for (size_t i = 0; i < segments.size(); i++) {
Segment* seg = segments[i];
const char* name = seg->segname;
if (!strcmp(name, SEG_PAGEZERO) || !strcmp(name, SEG_LINKEDIT)) {
continue;
}
LOG << seg->segname << ": "
<< "fileoff=" << seg->fileoff
<< ", vmaddr=" << seg->vmaddr << endl;
int prot = 0;
if (seg->initprot & VM_PROT_READ) {
prot |= PROT_READ;
}
if (seg->initprot & VM_PROT_WRITE) {
prot |= PROT_WRITE;
}
if (seg->initprot & VM_PROT_EXECUTE) {
prot |= PROT_EXEC;
}
intptr filesize = alignMem(seg->filesize, 0x1000);
intptr vmaddr = seg->vmaddr + *slide;
if (vmaddr < last_addr_) {
LOG << "will rebase: filename=" << mach.filename()
<< ", vmaddr=" << (void*)vmaddr
<< ", last_addr=" << (void*)last_addr_ << endl;
CHECK(i == 0);
vmaddr = last_addr_;
*slide = vmaddr - seg->vmaddr;
}
*base = min(*base, vmaddr);
intptr vmsize = seg->vmsize;
LOG << "mmap(file) " << mach.filename() << ' ' << name
<< ": " << (void*)vmaddr << "-" << (void*)(vmaddr + filesize)
<< " offset=" << mach.offset() + seg->fileoff << endl;
void* mapped = mmap((void*)vmaddr, filesize, prot,
MAP_PRIVATE | MAP_FIXED,
mach.fd(), mach.offset() + seg->fileoff);
if (mapped == MAP_FAILED) {
err(1, "%s mmap(file) failed", mach.filename().c_str());
}
if (vmsize != filesize) {
CHECK(vmsize > filesize);
LOG << "mmap(anon) " << mach.filename() << ' ' << name
<< ": " << (void*)(vmaddr + filesize) << "-"
<< (void*)(vmaddr + vmsize)
<< endl;
void* mapped = mmap((void*)(vmaddr + filesize),
vmsize - filesize, prot,
MAP_PRIVATE | MAP_FIXED | MAP_ANONYMOUS,
0, 0);
if (mapped == MAP_FAILED) {
err(1, "%s mmap(anon) failed", mach.filename().c_str());
}
}
last_addr_ = max(last_addr_, (intptr)vmaddr + vmsize);
}
}
void doRebase(const MachO& mach, intptr slide) {
for (size_t i = 0; i < mach.rebases().size(); i++) {
const MachO::Rebase& rebase = *mach.rebases()[i];
switch (rebase.type) {
case REBASE_TYPE_POINTER: {
char** ptr = (char**)(rebase.vmaddr + slide);
LOG << "rebase: " << i << ": " << (void*)rebase.vmaddr << ' '
<< (void*)*ptr << " => "
<< (void*)(*ptr + slide) << " @" << ptr << endl;
*ptr += slide;
break;
}
default:
fprintf(stderr, "Unknown rebase type: %d\n", rebase.type);
exit(1);
}
}
}
void loadInitFuncs(const MachO& mach, intptr slide) {
for (size_t i = 0; i < mach.init_funcs().size(); i++) {
init_funcs_.push_back(mach.init_funcs()[i] + slide);
}
}
void loadDylibs(const MachO& mach) {
for (size_t i = 0; i < mach.dylibs().size(); i++) {
string dylib = mach.dylibs()[i];
// For now, we assume a dylib is a system library if its path
// starts with /
// TODO(hamaji): Do something?
if (dylib[0] == '/') {
continue;
}
static const char executable_str[] = "@executable_path";
static const size_t executable_str_len = strlen(executable_str);
if (!strncmp(dylib.c_str(), executable_str, executable_str_len)) {
string dir = g_darwin_executable_path;
size_t found = dir.rfind('/');
if (found == string::npos) {
dir = ".";
} else {
dir = dir.substr(0, found);
}
dylib.replace(0, executable_str_len, dir);
}
auto_ptr<MachO> dylib_mach(MachO::read(dylib.c_str(), ARCH_NAME));
load(*dylib_mach);
}
}
void doBind(const MachO& mach, intptr slide) {
unsigned int common_code_size = (unsigned int)trampoline_.size();
// Ensure that we won't change the address.
trampoline_.reserve(common_code_size +
(1 + 6 + 5 + 10 + 3 + 2 + 1) * mach.binds().size());
g_bound_names.resize(mach.binds().size());
for (size_t i = 0; i < mach.binds().size(); i++) {
MachO::Bind* bind = mach.binds()[i];
if (bind->name[0] != '_') {
LOG << bind->name << ": skipping" << endl;
continue;
}
if (bind->type == BIND_TYPE_POINTER) {
const char* name = bind->name + 1;
map<string, string>::const_iterator found =
g_rename.find(name);
if (found != g_rename.end()) {
LOG << "Applying renaming: " << name
<< " => " << found->second.c_str() << endl;
name = found->second.c_str();
}
void** ptr = (void**)(bind->vmaddr + slide);
char* sym = NULL;
const map<string, MachO::Export>::const_iterator export_found =
exports_.find(bind->name);
if (export_found != exports_.end()) {
sym = (char*)export_found->second.addr;
}
if (!sym) {
sym = (char*)dlsym(RTLD_DEFAULT, name);
}
if (!sym) {
ERR << name << ": undefined symbol" << endl;
sym = (char*)&undefinedFunction;
}
sym += bind->addend;
LOG << "bind " << name << ": "
<< *ptr << " => " << (void*)sym << " @" << ptr << endl;
if (FLAGS_TRACE_FUNCTIONS && !g_no_trampoline.count(name)) {
LOG << "Generating trampoline for " << name << "..." << endl;
*ptr = &trampoline_[0] + trampoline_.size();
g_bound_names[i] = name;
// push %rax ; to adjust alignment for sse
pushTrampolineCode(0x50);
// mov $i, %r10d
pushTrampolineCode(0xba41);
pushTrampolineCode32((unsigned int)i);
// call &trampoline_[0]
pushTrampolineCode(0xe8);
pushTrampolineCode32((unsigned int)(-4-trampoline_.size()));
// mov $sym, %r10
pushTrampolineCode(0xba49);
pushTrampolineCode64((unsigned long long)(void*)sym);
// call *%r10
pushTrampolineCode(0xd2ff41);
// pop %r10
pushTrampolineCode(0x5a41);
// ret
pushTrampolineCode(0xc3);
} else {
*ptr = sym;
}
} else {
fprintf(stderr, "Unknown bind type: %d\n", bind->type);
abort();
}
}
}
void loadExports(const MachO& mach, intptr base,
map<string, MachO::Export>* exports) {
for (size_t i = 0; i < mach.exports().size(); i++) {
MachO::Export exp = mach.exports()[i];
exp.addr += base;
if (!exports->insert(make_pair(exp.name, exp)).second) {
fprintf(stderr, "duplicated exported symbol: %s\n", exp.name.c_str());
}
}
}
void loadSymbols(const MachO& mach, intptr slide, intptr base) {
g_file_map.add(mach, slide, base);
}
void load(const MachO& mach, map<string, MachO::Export>* exports = NULL) {
if (!exports) {
exports = &exports_;
}
intptr slide = 0;
intptr base = 0;
loadSegments(mach, &slide, &base);
doRebase(mach, slide);
loadInitFuncs(mach, slide);
loadDylibs(mach);
doBind(mach, slide);
loadExports(mach, base, exports);
loadSymbols(mach, slide, base);
}
void setupDyldData(const MachO& mach) {
if (!mach.dyld_data())
return;
void** dyld_data = (void**)mach.dyld_data();
dyld_data[1] = reinterpret_cast<void*>(&lookupDyldFunction);
}
void runInitFuncs(int argc, char** argv, char** envp, char** apple) {
for (size_t i = 0; i < init_funcs_.size(); i++) {
void** init_func = (void**)init_funcs_[i];
LOG << "calling initializer function " << *init_func << endl;
if (argc >= 0) {
((void(*)(int, char**, char**, char**))*init_func)(
argc, argv, envp, apple);
} else {
((void(*)())*init_func)();
}
}
init_funcs_.clear();
}
void run(const MachO& mach, int argc, char** argv, char** envp) {
// I don't understand what it is.
char* apple[2];
apple[0] = argv[0];
apple[1] = NULL;
load(mach);
setupDyldData(mach);
g_file_map.addWatchDog(last_addr_ + 1);
char* trampoline_start_addr =
(char*)(((uintptr_t)&trampoline_[0]) & ~0xfff);
uint64_t trampoline_size =
alignMem(&trampoline_[0] + trampoline_.size() - trampoline_start_addr,
0x1000);
mprotect(trampoline_start_addr, trampoline_size,
PROT_READ | PROT_WRITE | PROT_EXEC);
if (FLAGS_PRINT_TIME) {
double elapsed = ((double)clock() - g_start_time) / CLOCKS_PER_SEC;
printf("Elapsed time: %f sec\n", elapsed);
}
runInitFuncs(argc, argv, envp, apple);
LOG << "booting from " << (void*)mach.entry() << "..." << endl;
fflush(stdout);
CHECK(argc > 0);
boot(mach.entry(), argc, argv, envp);
/*
int (*fp)(int, char**, char**) =
(int(*)(int, char**, char**))mach.entry();
int ret = fp(argc, argv, envp);
exit(ret);
*/
}
private:
void boot(uint64_t entry, int argc, char** argv, char** envp);
void pushTrampolineCode(unsigned int c) {
while (c) {
trampoline_.push_back(c & 255);
c = c >> 8;
}
}
void pushTrampolineCode64(unsigned long long c) {
for (int i = 0; i < 8; i++) {
trampoline_.push_back(c & 255);
c = c >> 8;
}
}
void pushTrampolineCode32(unsigned int c) {
for (int i = 0; i < 4; i++) {
trampoline_.push_back(c & 255);
c = c >> 8;
}
}
string trampoline_;
intptr last_addr_;
vector<uint64_t> init_funcs_;
map<string, MachO::Export> exports_;
};
template <>
void MachOLoader<true>::boot(
uint64_t entry, int argc, char** argv, char** envp) {
__asm__ volatile(" mov %1, %%eax;\n"
" mov %2, %%rdx;\n"
" push $0;\n"
".loop64:\n"
" sub $8, %%rdx;\n"
" push (%%rdx);\n"
" dec %%eax;\n"
" jnz .loop64;\n"
" mov %1, %%eax;\n"
" push %%rax;\n"
" jmp *%0;\n"
::"r"(entry), "r"(argc), "r"(argv + argc), "r"(envp)
:"%rax", "%rdx");
//fprintf(stderr, "done!\n");
}
template <>
void MachOLoader<false>::boot(
uint64_t entry, int argc, char** argv, char** envp) {
__asm__ volatile(""
::"r"(entry), "r"(argc), "r"(argv), "r"(envp));
}
template <bool is64>
void runMachO(const MachO& mach, int argc, char** argv, char** envp) {
MachOLoader<is64> loader;
g_loader = &loader;
loader.run(mach, argc, argv, envp);
g_loader = NULL;
}
#if 0
static int getBacktrace(void** trace, int max_depth) {
typedef struct frame {
struct frame *bp;
void *ret;
} frame;
int depth;
frame* bp = (frame*)__builtin_frame_address(0);
for (depth = 0; bp && depth < max_depth; depth++) {
trace[depth] = bp->ret;
bp = bp->bp;
}
return depth;
}
#endif
extern "C" {
const char* dumpSymbol(void* p) {
return g_file_map.dumpSymbol(p);
}
}
/* signal handler for fatal errors */
static void handleSignal(int signum, siginfo_t* siginfo, void* vuc) {
ucontext_t *uc = (ucontext_t*)vuc;
void* pc = (void*)uc->uc_mcontext.gregs[REG_RIP];
fprintf(stderr, "%s(%d) %d (@%p) PC: %p\n\n",
strsignal(signum), signum, siginfo->si_code, siginfo->si_addr, pc);
void* trace[100];
int len = backtrace(trace, 99);
//int len = getBacktrace(trace, 99);
char** syms = backtrace_symbols(trace, len);
for (int i = len - 1; i > 0; i--) {
if (syms[i] && syms[i][0] != '[') {
fprintf(stderr, "%s\n", syms[i]);
} else {
const char* s = dumpSymbol(trace[i]);
if (s) {
fprintf(stderr, "%s\n", s);
} else {
fprintf(stderr, "%p\n", trace[i]);
}
}
}
}
/* Generate a stack backtrace when a CPU exception occurs. */
static void initSignalHandler() {
struct sigaction sigact;
sigact.sa_flags = SA_SIGINFO | SA_RESETHAND;
sigact.sa_sigaction = handleSignal;
sigemptyset(&sigact.sa_mask);
sigaction(SIGFPE, &sigact, NULL);
sigaction(SIGILL, &sigact, NULL);
sigaction(SIGSEGV, &sigact, NULL);
sigaction(SIGBUS, &sigact, NULL);
sigaction(SIGABRT, &sigact, NULL);
}
static bool loadLibMac(const char* mypath) {
if (dlopen("libmac.so", RTLD_NOW | RTLD_GLOBAL)) {
return true;
}
if (dlopen("libmac/libmac.so", RTLD_NOW | RTLD_GLOBAL)) {
return true;
}
char buf[PATH_MAX + 100];
strcpy(buf, mypath);
char* p = strrchr(buf, '/');
if (!p) {
fprintf(stderr, "Weird loader path: %s\n", mypath);
exit(1);
}
strcpy(p, "/libmac/libmac.so");
if (dlopen(buf, RTLD_NOW | RTLD_GLOBAL)) {
return true;
}
return false;
}
static void initLibMac() {
char mypath[PATH_MAX + 1];
ssize_t l = readlink("/proc/self/exe", mypath, PATH_MAX);
if (l < 0) {
err(1, "readlink for /proc/self/exe");
}
mypath[l] = '\0';
if (!loadLibMac(mypath)) {
fprintf(stderr, "libmac not found\n");
exit(1);
}
int* LIBMAC_LOG = (int*)dlsym(RTLD_DEFAULT, "LIBMAC_LOG");
if (LIBMAC_LOG) {
*LIBMAC_LOG = FLAGS_LOG;
}
char* loader_path = (char*)dlsym(RTLD_DEFAULT, "__loader_path");
if (!loader_path) {
fprintf(stderr, "wrong libmac: __loader_path not found\n");
exit(1);
}
strcpy(loader_path, mypath);
}
static string ld_mac_dlerror_buf;
static bool ld_mac_dlerror_is_set;
static void* ld_mac_dlopen(const char* filename, int flag) {
LOG << "ld_mac_dlopen: " << filename << " " << flag << endl;
// TODO(hamaji): Handle failures.
auto_ptr<MachO> dylib_mach(MachO::read(filename, ARCH_NAME));
// TODO(hamaji): Consider 32bit.
MachOLoader<true>* loader = (MachOLoader<true>*)g_loader;
CHECK(loader);
map<string, MachO::Export>* exports = new map<string, MachO::Export>;
loader->load(*dylib_mach, exports);
loader->runInitFuncs(-1, NULL, NULL, NULL);
return exports;
}
static int ld_mac_dlclose(void* handle) {
LOG << "ld_mac_dlclose" << endl;
delete (map<string, MachO::Export>*)handle;
return 0;
}
static const char* ld_mac_dlerror(void) {
LOG << "ld_mac_dlerror" << endl;
if (!ld_mac_dlerror_is_set)
return NULL;
ld_mac_dlerror_is_set = false;
return ld_mac_dlerror_buf.c_str();
}
static void* ld_mac_dlsym(void* handle, const char* symbol) {
LOG << "ld_mac_dlsym: " << symbol << endl;
map<string, MachO::Export>* exports = (map<string, MachO::Export>*)handle;
map<string, MachO::Export>::const_iterator found = exports->find(
string("_") + symbol);
if (found == exports->end()) {
ld_mac_dlerror_is_set = true;
ld_mac_dlerror_buf = string("undefined symbol: ") + symbol;
return NULL;
}
return (void*)found->second.addr;
}
void initDlfcn() {
#define SET_DLFCN_FUNC(f) \
do { \
void** p = (void**)dlsym(RTLD_DEFAULT, "ld_mac_" #f); \
*p = (void*)&ld_mac_ ## f; \
} while (0)
SET_DLFCN_FUNC(dlopen);
SET_DLFCN_FUNC(dlclose);
SET_DLFCN_FUNC(dlerror);
SET_DLFCN_FUNC(dlsym);
}
int main(int argc, char* argv[], char* envp[]) {
if (FLAGS_PRINT_TIME) {
g_start_time = clock();
}
initSignalHandler();
initRename();
initNoTrampoline();
initLibMac();
initDlfcn();
argc--;
argv++;
for (;;) {
if (argc == 0) {
fprintf(stderr, "An argument required.\n");
exit(1);
}
const char* arg = argv[0];
if (arg[0] != '-') {
break;
}
// TODO(hamaji): Do something for switches.
argc--;
argv++;
}
g_darwin_executable_path =
(char*)dlsym(RTLD_DEFAULT, "__darwin_executable_path");
if (!realpath(argv[0], g_darwin_executable_path)) {
}
auto_ptr<MachO> mach(MachO::read(argv[0], ARCH_NAME));
if (mach->is64()) {
runMachO<true>(*mach, argc, argv, envp);
} else {
runMachO<false>(*mach, argc, argv, envp);
}
}
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