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llvm-project/compiler-rt/lib/asan/asan_mac.cc

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//===-- asan_mac.cc -------------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file is a part of AddressSanitizer, an address sanity checker.
//
// Mac-specific details.
//===----------------------------------------------------------------------===//
#include "sanitizer_common/sanitizer_platform.h"
#if SANITIZER_MAC
#include "asan_interceptors.h"
#include "asan_internal.h"
#include "asan_mapping.h"
#include "asan_stack.h"
#include "asan_thread.h"
#include "sanitizer_common/sanitizer_atomic.h"
#include "sanitizer_common/sanitizer_libc.h"
#include "sanitizer_common/sanitizer_mac.h"
#if !SANITIZER_IOS
#include <crt_externs.h> // for _NSGetArgv and _NSGetEnviron
#else
extern "C" {
extern char ***_NSGetArgv(void);
}
#endif
#include <dlfcn.h> // for dladdr()
#include <mach-o/dyld.h>
#include <mach-o/loader.h>
#include <sys/mman.h>
#include <sys/resource.h>
#include <sys/sysctl.h>
#include <sys/ucontext.h>
#include <fcntl.h>
#include <pthread.h>
#include <stdlib.h> // for free()
#include <unistd.h>
#include <libkern/OSAtomic.h>
namespace __asan {
void InitializePlatformInterceptors() {}
bool PlatformHasDifferentMemcpyAndMemmove() {
// On OS X 10.7 memcpy() and memmove() are both resolved
// into memmove$VARIANT$sse42.
// See also http://code.google.com/p/address-sanitizer/issues/detail?id=34.
// TODO(glider): need to check dynamically that memcpy() and memmove() are
// actually the same function.
return GetMacosVersion() == MACOS_VERSION_SNOW_LEOPARD;
}
extern "C"
void __asan_init();
static const char kDyldInsertLibraries[] = "DYLD_INSERT_LIBRARIES";
LowLevelAllocator allocator_for_env;
// Change the value of the env var |name|, leaking the original value.
// If |name_value| is NULL, the variable is deleted from the environment,
// otherwise the corresponding "NAME=value" string is replaced with
// |name_value|.
void LeakyResetEnv(const char *name, const char *name_value) {
char **env = GetEnviron();
uptr name_len = internal_strlen(name);
while (*env != 0) {
uptr len = internal_strlen(*env);
if (len > name_len) {
const char *p = *env;
if (!internal_memcmp(p, name, name_len) && p[name_len] == '=') {
// Match.
if (name_value) {
// Replace the old value with the new one.
*env = const_cast<char*>(name_value);
} else {
// Shift the subsequent pointers back.
char **del = env;
do {
del[0] = del[1];
} while (*del++);
}
}
}
env++;
}
}
static bool reexec_disabled = false;
void DisableReexec() {
reexec_disabled = true;
}
extern "C" double dyldVersionNumber;
static const double kMinDyldVersionWithAutoInterposition = 360.0;
bool DyldNeedsEnvVariable() {
// If running on OS X 10.11+ or iOS 9.0+, dyld will interpose even if
// DYLD_INSERT_LIBRARIES is not set. However, checking OS version via
// GetMacosVersion() doesn't work for the simulator. Let's instead check
// `dyldVersionNumber`, which is exported by dyld, against a known version
// number from the first OS release where this appeared.
return dyldVersionNumber < kMinDyldVersionWithAutoInterposition;
}
void MaybeReexec() {
if (reexec_disabled) return;
// Make sure the dynamic ASan runtime library is preloaded so that the
// wrappers work. If it is not, set DYLD_INSERT_LIBRARIES and re-exec
// ourselves.
Dl_info info;
CHECK(dladdr((void*)((uptr)__asan_init), &info));
char *dyld_insert_libraries =
const_cast<char*>(GetEnv(kDyldInsertLibraries));
uptr old_env_len = dyld_insert_libraries ?
internal_strlen(dyld_insert_libraries) : 0;
uptr fname_len = internal_strlen(info.dli_fname);
const char *dylib_name = StripModuleName(info.dli_fname);
uptr dylib_name_len = internal_strlen(dylib_name);
bool lib_is_in_env =
dyld_insert_libraries && REAL(strstr)(dyld_insert_libraries, dylib_name);
if (DyldNeedsEnvVariable() && !lib_is_in_env) {
// DYLD_INSERT_LIBRARIES is not set or does not contain the runtime
// library.
char program_name[1024];
uint32_t buf_size = sizeof(program_name);
_NSGetExecutablePath(program_name, &buf_size);
char *new_env = const_cast<char*>(info.dli_fname);
if (dyld_insert_libraries) {
// Append the runtime dylib name to the existing value of
// DYLD_INSERT_LIBRARIES.
new_env = (char*)allocator_for_env.Allocate(old_env_len + fname_len + 2);
internal_strncpy(new_env, dyld_insert_libraries, old_env_len);
new_env[old_env_len] = ':';
// Copy fname_len and add a trailing zero.
internal_strncpy(new_env + old_env_len + 1, info.dli_fname,
fname_len + 1);
// Ok to use setenv() since the wrappers don't depend on the value of
// asan_inited.
setenv(kDyldInsertLibraries, new_env, /*overwrite*/1);
} else {
// Set DYLD_INSERT_LIBRARIES equal to the runtime dylib name.
setenv(kDyldInsertLibraries, info.dli_fname, /*overwrite*/0);
}
VReport(1, "exec()-ing the program with\n");
VReport(1, "%s=%s\n", kDyldInsertLibraries, new_env);
VReport(1, "to enable ASan wrappers.\n");
execv(program_name, *_NSGetArgv());
// We get here only if execv() failed.
Report("ERROR: The process is launched without DYLD_INSERT_LIBRARIES, "
"which is required for ASan to work. ASan tried to set the "
"environment variable and re-execute itself, but execv() failed, "
"possibly because of sandbox restrictions. Make sure to launch the "
"executable with:\n%s=%s\n", kDyldInsertLibraries, new_env);
CHECK("execv failed" && 0);
}
if (!lib_is_in_env)
return;
// DYLD_INSERT_LIBRARIES is set and contains the runtime library. Let's remove
// the dylib from the environment variable, because interceptors are installed
// and we don't want our children to inherit the variable.
uptr env_name_len = internal_strlen(kDyldInsertLibraries);
// Allocate memory to hold the previous env var name, its value, the '='
// sign and the '\0' char.
char *new_env = (char*)allocator_for_env.Allocate(
old_env_len + 2 + env_name_len);
CHECK(new_env);
internal_memset(new_env, '\0', old_env_len + 2 + env_name_len);
internal_strncpy(new_env, kDyldInsertLibraries, env_name_len);
new_env[env_name_len] = '=';
char *new_env_pos = new_env + env_name_len + 1;
// Iterate over colon-separated pieces of |dyld_insert_libraries|.
char *piece_start = dyld_insert_libraries;
char *piece_end = NULL;
char *old_env_end = dyld_insert_libraries + old_env_len;
do {
if (piece_start[0] == ':') piece_start++;
piece_end = REAL(strchr)(piece_start, ':');
if (!piece_end) piece_end = dyld_insert_libraries + old_env_len;
if ((uptr)(piece_start - dyld_insert_libraries) > old_env_len) break;
uptr piece_len = piece_end - piece_start;
char *filename_start =
(char *)internal_memrchr(piece_start, '/', piece_len);
uptr filename_len = piece_len;
if (filename_start) {
filename_start += 1;
filename_len = piece_len - (filename_start - piece_start);
} else {
filename_start = piece_start;
}
// If the current piece isn't the runtime library name,
// append it to new_env.
if ((dylib_name_len != filename_len) ||
(internal_memcmp(filename_start, dylib_name, dylib_name_len) != 0)) {
if (new_env_pos != new_env + env_name_len + 1) {
new_env_pos[0] = ':';
new_env_pos++;
}
internal_strncpy(new_env_pos, piece_start, piece_len);
new_env_pos += piece_len;
}
// Move on to the next piece.
piece_start = piece_end;
} while (piece_start < old_env_end);
// Can't use setenv() here, because it requires the allocator to be
// initialized.
// FIXME: instead of filtering DYLD_INSERT_LIBRARIES here, do it in
// a separate function called after InitializeAllocator().
if (new_env_pos == new_env + env_name_len + 1) new_env = NULL;
LeakyResetEnv(kDyldInsertLibraries, new_env);
}
// No-op. Mac does not support static linkage anyway.
void *AsanDoesNotSupportStaticLinkage() {
return 0;
}
// No-op. Mac does not support static linkage anyway.
void AsanCheckDynamicRTPrereqs() {}
// No-op. Mac does not support static linkage anyway.
void AsanCheckIncompatibleRT() {}
void ReadContextStack(void *context, uptr *stack, uptr *ssize) {
UNIMPLEMENTED();
}
// Support for the following functions from libdispatch on Mac OS:
// dispatch_async_f()
// dispatch_async()
// dispatch_sync_f()
// dispatch_sync()
// dispatch_after_f()
// dispatch_after()
// dispatch_group_async_f()
// dispatch_group_async()
// TODO(glider): libdispatch API contains other functions that we don't support
// yet.
//
// dispatch_sync() and dispatch_sync_f() are synchronous, although chances are
// they can cause jobs to run on a thread different from the current one.
// TODO(glider): if so, we need a test for this (otherwise we should remove
// them).
//
// The following functions use dispatch_barrier_async_f() (which isn't a library
// function but is exported) and are thus supported:
// dispatch_source_set_cancel_handler_f()
// dispatch_source_set_cancel_handler()
// dispatch_source_set_event_handler_f()
// dispatch_source_set_event_handler()
//
// The reference manual for Grand Central Dispatch is available at
// http://developer.apple.com/library/mac/#documentation/Performance/Reference/GCD_libdispatch_Ref/Reference/reference.html
// The implementation details are at
// http://libdispatch.macosforge.org/trac/browser/trunk/src/queue.c
typedef void* dispatch_group_t;
typedef void* dispatch_queue_t;
typedef void* dispatch_source_t;
typedef u64 dispatch_time_t;
typedef void (*dispatch_function_t)(void *block);
typedef void* (*worker_t)(void *block);
// A wrapper for the ObjC blocks used to support libdispatch.
typedef struct {
void *block;
dispatch_function_t func;
u32 parent_tid;
} asan_block_context_t;
ALWAYS_INLINE
void asan_register_worker_thread(int parent_tid, StackTrace *stack) {
AsanThread *t = GetCurrentThread();
if (!t) {
t = AsanThread::Create(/* start_routine */ nullptr, /* arg */ nullptr,
parent_tid, stack, /* detached */ true);
t->Init();
asanThreadRegistry().StartThread(t->tid(), 0, 0);
SetCurrentThread(t);
}
}
// For use by only those functions that allocated the context via
// alloc_asan_context().
extern "C"
void asan_dispatch_call_block_and_release(void *block) {
GET_STACK_TRACE_THREAD;
asan_block_context_t *context = (asan_block_context_t*)block;
VReport(2,
"asan_dispatch_call_block_and_release(): "
"context: %p, pthread_self: %p\n",
block, pthread_self());
asan_register_worker_thread(context->parent_tid, &stack);
// Call the original dispatcher for the block.
context->func(context->block);
asan_free(context, &stack, FROM_MALLOC);
}
} // namespace __asan
using namespace __asan; // NOLINT
// Wrap |ctxt| and |func| into an asan_block_context_t.
// The caller retains control of the allocated context.
extern "C"
asan_block_context_t *alloc_asan_context(void *ctxt, dispatch_function_t func,
BufferedStackTrace *stack) {
asan_block_context_t *asan_ctxt =
(asan_block_context_t*) asan_malloc(sizeof(asan_block_context_t), stack);
asan_ctxt->block = ctxt;
asan_ctxt->func = func;
asan_ctxt->parent_tid = GetCurrentTidOrInvalid();
return asan_ctxt;
}
// Define interceptor for dispatch_*_f function with the three most common
// parameters: dispatch_queue_t, context, dispatch_function_t.
#define INTERCEPT_DISPATCH_X_F_3(dispatch_x_f) \
INTERCEPTOR(void, dispatch_x_f, dispatch_queue_t dq, void *ctxt, \
dispatch_function_t func) { \
GET_STACK_TRACE_THREAD; \
asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); \
if (Verbosity() >= 2) { \
Report(#dispatch_x_f "(): context: %p, pthread_self: %p\n", \
asan_ctxt, pthread_self()); \
PRINT_CURRENT_STACK(); \
} \
return REAL(dispatch_x_f)(dq, (void*)asan_ctxt, \
asan_dispatch_call_block_and_release); \
}
INTERCEPT_DISPATCH_X_F_3(dispatch_async_f)
INTERCEPT_DISPATCH_X_F_3(dispatch_sync_f)
INTERCEPT_DISPATCH_X_F_3(dispatch_barrier_async_f)
INTERCEPTOR(void, dispatch_after_f, dispatch_time_t when,
dispatch_queue_t dq, void *ctxt,
dispatch_function_t func) {
GET_STACK_TRACE_THREAD;
asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack);
if (Verbosity() >= 2) {
Report("dispatch_after_f: %p\n", asan_ctxt);
PRINT_CURRENT_STACK();
}
return REAL(dispatch_after_f)(when, dq, (void*)asan_ctxt,
asan_dispatch_call_block_and_release);
}
INTERCEPTOR(void, dispatch_group_async_f, dispatch_group_t group,
dispatch_queue_t dq, void *ctxt,
dispatch_function_t func) {
GET_STACK_TRACE_THREAD;
asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack);
if (Verbosity() >= 2) {
Report("dispatch_group_async_f(): context: %p, pthread_self: %p\n",
asan_ctxt, pthread_self());
PRINT_CURRENT_STACK();
}
REAL(dispatch_group_async_f)(group, dq, (void*)asan_ctxt,
asan_dispatch_call_block_and_release);
}
#if !defined(MISSING_BLOCKS_SUPPORT)
extern "C" {
void dispatch_async(dispatch_queue_t dq, void(^work)(void));
void dispatch_group_async(dispatch_group_t dg, dispatch_queue_t dq,
void(^work)(void));
void dispatch_after(dispatch_time_t when, dispatch_queue_t queue,
void(^work)(void));
void dispatch_source_set_cancel_handler(dispatch_source_t ds,
void(^work)(void));
void dispatch_source_set_event_handler(dispatch_source_t ds, void(^work)(void));
}
#define GET_ASAN_BLOCK(work) \
void (^asan_block)(void); \
int parent_tid = GetCurrentTidOrInvalid(); \
asan_block = ^(void) { \
GET_STACK_TRACE_THREAD; \
asan_register_worker_thread(parent_tid, &stack); \
work(); \
}
INTERCEPTOR(void, dispatch_async,
dispatch_queue_t dq, void(^work)(void)) {
ENABLE_FRAME_POINTER;
GET_ASAN_BLOCK(work);
REAL(dispatch_async)(dq, asan_block);
}
INTERCEPTOR(void, dispatch_group_async,
dispatch_group_t dg, dispatch_queue_t dq, void(^work)(void)) {
ENABLE_FRAME_POINTER;
GET_ASAN_BLOCK(work);
REAL(dispatch_group_async)(dg, dq, asan_block);
}
INTERCEPTOR(void, dispatch_after,
dispatch_time_t when, dispatch_queue_t queue, void(^work)(void)) {
ENABLE_FRAME_POINTER;
GET_ASAN_BLOCK(work);
REAL(dispatch_after)(when, queue, asan_block);
}
INTERCEPTOR(void, dispatch_source_set_cancel_handler,
dispatch_source_t ds, void(^work)(void)) {
if (!work) {
REAL(dispatch_source_set_cancel_handler)(ds, work);
return;
}
ENABLE_FRAME_POINTER;
GET_ASAN_BLOCK(work);
REAL(dispatch_source_set_cancel_handler)(ds, asan_block);
}
INTERCEPTOR(void, dispatch_source_set_event_handler,
dispatch_source_t ds, void(^work)(void)) {
ENABLE_FRAME_POINTER;
GET_ASAN_BLOCK(work);
REAL(dispatch_source_set_event_handler)(ds, asan_block);
}
#endif
#endif // SANITIZER_MAC
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