ref: 4010db3078491baf3cb0d3d4e3a60c0cea114471
dir: /third_party/boringssl/src/crypto/test/abi_test.cc/
/* Copyright (c) 2018, Google Inc.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
#include "abi_test.h"
#include <stdarg.h>
#include <stdio.h>
#include <algorithm>
#include <array>
#include <openssl/mem.h>
#include <openssl/rand.h>
#include <openssl/span.h>
#if defined(OPENSSL_X86_64) && defined(SUPPORTS_ABI_TEST)
#if defined(OPENSSL_LINUX) && defined(BORINGSSL_HAVE_LIBUNWIND)
#define SUPPORTS_UNWIND_TEST
#define UNW_LOCAL_ONLY
#include <errno.h>
#include <fcntl.h>
#include <libunwind.h>
#include <pthread.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#elif defined(OPENSSL_WINDOWS)
#define SUPPORTS_UNWIND_TEST
OPENSSL_MSVC_PRAGMA(warning(push, 3))
#include <windows.h>
#include <dbghelp.h>
OPENSSL_MSVC_PRAGMA(warning(pop))
#endif
#endif // X86_64 && SUPPORTS_ABI_TEST
// FIPS mode breaks unwind tests. See https://crbug.com/boringssl/289.
#if defined(BORINGSSL_FIPS)
#undef SUPPORTS_UNWIND_TEST
#endif
namespace abi_test {
namespace internal {
static bool g_unwind_tests_enabled = false;
std::string FixVAArgsString(const char *str) {
std::string ret = str;
size_t idx = ret.find(',');
if (idx == std::string::npos) {
return ret + "()";
}
size_t idx2 = idx + 1;
while (idx2 < ret.size() && ret[idx2] == ' ') {
idx2++;
}
while (idx > 0 && ret[idx - 1] == ' ') {
idx--;
}
return ret.substr(0, idx) + "(" + ret.substr(idx2) + ")";
}
#if defined(SUPPORTS_ABI_TEST)
// ForEachMismatch calls |func| for each register where |a| and |b| differ.
template <typename Func>
static void ForEachMismatch(const CallerState &a, const CallerState &b,
const Func &func) {
#define CALLER_STATE_REGISTER(type, name) \
if (a.name != b.name) { \
func(#name); \
}
LOOP_CALLER_STATE_REGISTERS()
#undef CALLER_STATE_REGISTER
}
// ReadUnwindResult adds the results of the most recent unwind test to |out|.
static void ReadUnwindResult(Result *out);
crypto_word_t RunTrampoline(Result *out, crypto_word_t func,
const crypto_word_t *argv, size_t argc,
bool unwind) {
CallerState state;
RAND_bytes(reinterpret_cast<uint8_t *>(&state), sizeof(state));
unwind &= g_unwind_tests_enabled;
CallerState state2 = state;
crypto_word_t ret = abi_test_trampoline(func, &state2, argv, argc, unwind);
#if defined(OPENSSL_X86_64) || defined(OPENSSL_X86)
// Query and clear the direction flag early, so negative tests do not
// interfere with |malloc|.
bool direction_flag = abi_test_get_and_clear_direction_flag();
#endif // OPENSSL_X86_64 || OPENSSL_X86
*out = Result();
ForEachMismatch(state, state2, [&](const char *reg) {
out->errors.push_back(std::string(reg) + " was not restored after return");
});
#if defined(OPENSSL_X86_64) || defined(OPENSSL_X86)
// Linux and Windows ABIs for x86 require the direction flag be cleared on
// return. (Some OpenSSL assembly preserves it, which is stronger, but we only
// require what is specified by the ABI so |CHECK_ABI| works with C compiler
// output.)
if (direction_flag) {
out->errors.emplace_back("Direction flag set after return");
}
#endif // OPENSSL_X86_64 || OPENSSL_X86
if (unwind) {
ReadUnwindResult(out);
}
return ret;
}
#endif // SUPPORTS_ABI_TEST
#if defined(SUPPORTS_UNWIND_TEST)
// We test unwind metadata by running the function under test with the trap flag
// set. This results in |SIGTRAP| and |EXCEPTION_SINGLE_STEP| on Linux and
// Windows, respectively. We hande these and verify libunwind or the Windows
// unwind APIs unwind successfully.
// IsAncestorStackFrame returns true if |a_sp| is an ancestor stack frame of
// |b_sp|.
static bool IsAncestorStackFrame(crypto_word_t a_sp, crypto_word_t b_sp) {
#if defined(OPENSSL_X86_64)
// The stack grows down, so ancestor stack frames have higher addresses.
return a_sp > b_sp;
#else
#error "unknown architecture"
#endif
}
// Implement some string formatting utilties. Ideally we would use |snprintf|,
// but this is called in a signal handler and |snprintf| is not async-signal-
// safe.
#if !defined(OPENSSL_WINDOWS)
static std::array<char, DECIMAL_SIZE(crypto_word_t) + 1> WordToDecimal(
crypto_word_t v) {
std::array<char, DECIMAL_SIZE(crypto_word_t) + 1> ret;
size_t len = 0;
do {
ret[len++] = '0' + v % 10;
v /= 10;
} while (v != 0);
for (size_t i = 0; i < len / 2; i++) {
std::swap(ret[i], ret[len - 1 - i]);
}
ret[len] = '\0';
return ret;
}
#endif // !OPENSSL_WINDOWS
static std::array<char, sizeof(crypto_word_t) * 2 + 1> WordToHex(
crypto_word_t v) {
static const char kHex[] = "0123456789abcdef";
std::array<char, sizeof(crypto_word_t) * 2 + 1> ret;
for (size_t i = sizeof(crypto_word_t) - 1; i < sizeof(crypto_word_t); i--) {
uint8_t b = v & 0xff;
v >>= 8;
ret[i * 2] = kHex[b >> 4];
ret[i * 2 + 1] = kHex[b & 0xf];
}
ret[sizeof(crypto_word_t) * 2] = '\0';
return ret;
}
static void StrCatSignalSafeImpl(bssl::Span<char> out) {}
template <typename... Args>
static void StrCatSignalSafeImpl(bssl::Span<char> out, const char *str,
Args... args) {
OPENSSL_strlcat(out.data(), str, out.size());
StrCatSignalSafeImpl(out, args...);
}
template <typename... Args>
static void StrCatSignalSafe(bssl::Span<char> out, Args... args) {
if (out.empty()) {
return;
}
out[0] = '\0';
StrCatSignalSafeImpl(out, args...);
}
template <typename... Args>
[[noreturn]] static void FatalError(Args... args) {
// We cannot use |snprintf| here because it is not async-signal-safe.
char buf[512];
StrCatSignalSafe(buf, args..., "\n");
#if defined(OPENSSL_WINDOWS)
HANDLE stderr_handle = GetStdHandle(STD_ERROR_HANDLE);
if (stderr_handle != INVALID_HANDLE_VALUE) {
DWORD unused;
WriteFile(stderr_handle, buf, strlen(buf), &unused, nullptr);
}
#else
write(STDERR_FILENO, buf, strlen(buf));
#endif
abort();
}
class UnwindStatus {
public:
UnwindStatus() : err_(nullptr) {}
explicit UnwindStatus(const char *err) : err_(err) {}
bool ok() const { return err_ == nullptr; }
const char *Error() const { return err_; }
private:
const char *err_;
};
template<typename T>
class UnwindStatusOr {
public:
UnwindStatusOr(UnwindStatus status) : status_(status) {
assert(!status_.ok());
}
UnwindStatusOr(const T &value) : status_(UnwindStatus()), value_(value) {}
bool ok() const { return status_.ok(); }
const char *Error() const { return status_.Error(); }
const T &ValueOrDie(const char *msg = "Unexpected error") const {
if (!ok()) {
FatalError(msg, ": ", Error());
}
return value_;
}
private:
UnwindStatus status_;
T value_;
};
// UnwindCursor abstracts between libunwind and Windows unwind APIs. It is
// async-signal-safe.
#if defined(OPENSSL_WINDOWS)
class UnwindCursor {
public:
explicit UnwindCursor(const CONTEXT &ctx) : ctx_(ctx) {
starting_ip_ = ctx_.Rip;
}
crypto_word_t starting_ip() const { return starting_ip_; }
// Step unwinds the cursor by one frame. On success, it returns whether there
// were more frames to unwind.
UnwindStatusOr<bool> Step() {
bool is_top = is_top_;
is_top_ = false;
DWORD64 image_base;
RUNTIME_FUNCTION *entry =
RtlLookupFunctionEntry(ctx_.Rip, &image_base, nullptr);
if (entry == nullptr) {
// This is a leaf function. Leaf functions do not touch stack or
// callee-saved registers, so they may be unwound by simulating a ret.
if (!is_top) {
return UnwindStatus("leaf function found below the top frame");
}
memcpy(&ctx_.Rip, reinterpret_cast<const void *>(ctx_.Rsp),
sizeof(ctx_.Rip));
ctx_.Rsp += 8;
return true;
}
// This is a frame function. Call into the Windows unwinder.
void *handler_data;
DWORD64 establisher_frame;
RtlVirtualUnwind(UNW_FLAG_NHANDLER, image_base, ctx_.Rip, entry, &ctx_,
&handler_data, &establisher_frame, nullptr);
return ctx_.Rip != 0;
}
// GetIP returns the instruction pointer at the current frame.
UnwindStatusOr<crypto_word_t> GetIP() { return ctx_.Rip; }
// GetSP returns the stack pointer at the current frame.
UnwindStatusOr<crypto_word_t> GetSP() { return ctx_.Rsp; }
// GetCallerState returns the callee-saved registers at the current frame.
UnwindStatusOr<CallerState> GetCallerState() {
CallerState state;
state.rbx = ctx_.Rbx;
state.rbp = ctx_.Rbp;
state.rdi = ctx_.Rdi;
state.rsi = ctx_.Rsi;
state.r12 = ctx_.R12;
state.r13 = ctx_.R13;
state.r14 = ctx_.R14;
state.r15 = ctx_.R15;
memcpy(&state.xmm6, &ctx_.Xmm6, sizeof(Reg128));
memcpy(&state.xmm7, &ctx_.Xmm7, sizeof(Reg128));
memcpy(&state.xmm8, &ctx_.Xmm8, sizeof(Reg128));
memcpy(&state.xmm9, &ctx_.Xmm9, sizeof(Reg128));
memcpy(&state.xmm10, &ctx_.Xmm10, sizeof(Reg128));
memcpy(&state.xmm11, &ctx_.Xmm11, sizeof(Reg128));
memcpy(&state.xmm12, &ctx_.Xmm12, sizeof(Reg128));
memcpy(&state.xmm13, &ctx_.Xmm13, sizeof(Reg128));
memcpy(&state.xmm14, &ctx_.Xmm14, sizeof(Reg128));
memcpy(&state.xmm15, &ctx_.Xmm15, sizeof(Reg128));
return state;
}
// ToString returns a human-readable representation of the address the cursor
// started at.
const char *ToString() {
StrCatSignalSafe(starting_ip_buf_, "0x", WordToHex(starting_ip_).data());
return starting_ip_buf_;
}
private:
CONTEXT ctx_;
crypto_word_t starting_ip_;
char starting_ip_buf_[64];
bool is_top_ = true;
};
#else // !OPENSSL_WINDOWS
class UnwindCursor {
public:
explicit UnwindCursor(unw_context_t *ctx) : ctx_(ctx) {
int ret = InitAtSignalFrame(&cursor_);
if (ret < 0) {
FatalError("Error getting unwind context: ", unw_strerror(ret));
}
starting_ip_ = GetIP().ValueOrDie("Error getting instruction pointer");
}
// Step unwinds the cursor by one frame. On success, it returns whether there
// were more frames to unwind.
UnwindStatusOr<bool> Step() {
int ret = unw_step(&cursor_);
if (ret < 0) {
return UNWError(ret);
}
return ret != 0;
}
// GetIP returns the instruction pointer at the current frame.
UnwindStatusOr<crypto_word_t> GetIP() {
crypto_word_t ip;
int ret = GetReg(&ip, UNW_REG_IP);
if (ret < 0) {
return UNWError(ret);
}
return ip;
}
// GetSP returns the stack pointer at the current frame.
UnwindStatusOr<crypto_word_t> GetSP() {
crypto_word_t sp;
int ret = GetReg(&sp, UNW_REG_SP);
if (ret < 0) {
return UNWError(ret);
}
return sp;
}
// GetCallerState returns the callee-saved registers at the current frame.
UnwindStatusOr<CallerState> GetCallerState() {
CallerState state;
int ret = 0;
#if defined(OPENSSL_X86_64)
ret = ret < 0 ? ret : GetReg(&state.rbx, UNW_X86_64_RBX);
ret = ret < 0 ? ret : GetReg(&state.rbp, UNW_X86_64_RBP);
ret = ret < 0 ? ret : GetReg(&state.r12, UNW_X86_64_R12);
ret = ret < 0 ? ret : GetReg(&state.r13, UNW_X86_64_R13);
ret = ret < 0 ? ret : GetReg(&state.r14, UNW_X86_64_R14);
ret = ret < 0 ? ret : GetReg(&state.r15, UNW_X86_64_R15);
#else
#error "unknown architecture"
#endif
if (ret < 0) {
return UNWError(ret);
}
return state;
}
// ToString returns a human-readable representation of the address the cursor
// started at, using debug information if available.
const char *ToString() {
// Use a new cursor. |cursor_| has already been unwound, and
// |unw_get_proc_name| is slow so we do not sample it unconditionally in the
// constructor.
unw_cursor_t cursor;
unw_word_t off;
if (InitAtSignalFrame(&cursor) != 0 ||
unw_get_proc_name(&cursor, starting_ip_buf_, sizeof(starting_ip_buf_),
&off) != 0) {
StrCatSignalSafe(starting_ip_buf_, "0x", WordToHex(starting_ip_).data());
return starting_ip_buf_;
}
size_t len = strlen(starting_ip_buf_);
// Print the offset in decimal, to match gdb's disassembly output and ease
// debugging.
StrCatSignalSafe(bssl::Span<char>(starting_ip_buf_).subspan(len), "+",
WordToDecimal(off).data(), " (0x",
WordToHex(starting_ip_).data(), ")");
return starting_ip_buf_;
}
private:
static UnwindStatus UNWError(int ret) {
assert(ret < 0);
const char *msg = unw_strerror(ret);
return UnwindStatus(msg == nullptr ? "unknown error" : msg);
}
int InitAtSignalFrame(unw_cursor_t *cursor) {
// Work around a bug in libunwind which breaks rax and rdx recovery. This
// breaks functions which temporarily use rax as the CFA register. See
// https://git.savannah.gnu.org/gitweb/?p=libunwind.git;a=commit;h=819bf51bbd2da462c2ec3401e8ac9153b6e725e3
OPENSSL_memset(cursor, 0, sizeof(*cursor));
int ret = unw_init_local(cursor, ctx_);
if (ret < 0) {
return ret;
}
for (;;) {
ret = unw_is_signal_frame(cursor);
if (ret < 0) {
return ret;
}
if (ret != 0) {
return 0; // Found the signal frame.
}
ret = unw_step(cursor);
if (ret < 0) {
return ret;
}
}
}
int GetReg(crypto_word_t *out, unw_regnum_t reg) {
unw_word_t val;
int ret = unw_get_reg(&cursor_, reg, &val);
if (ret >= 0) {
static_assert(sizeof(crypto_word_t) == sizeof(unw_word_t),
"crypto_word_t and unw_word_t are inconsistent");
*out = val;
}
return ret;
}
unw_context_t *ctx_;
unw_cursor_t cursor_;
crypto_word_t starting_ip_;
char starting_ip_buf_[64];
};
#endif // OPENSSL_WINDOWS
// g_in_trampoline is true if we are in an instrumented |abi_test_trampoline|
// call, in the region that triggers |SIGTRAP|.
static bool g_in_trampoline = false;
// g_unwind_function_done, if |g_in_trampoline| is true, is whether the function
// under test has returned. It is undefined otherwise.
static bool g_unwind_function_done;
// g_trampoline_state, if |g_in_trampoline| is true, is the state the function
// under test must preserve. It is undefined otherwise.
static CallerState g_trampoline_state;
// g_trampoline_sp, if |g_in_trampoline| is true, is the stack pointer of the
// trampoline frame. It is undefined otherwise.
static crypto_word_t g_trampoline_sp;
// kMaxUnwindErrors is the maximum number of unwind errors reported per
// function. If a function's unwind tables are wrong, we are otherwise likely to
// repeat the same error at multiple addresses.
static constexpr size_t kMaxUnwindErrors = 10;
// Errors are saved in a signal handler. We use a static buffer to avoid
// allocation.
static size_t g_num_unwind_errors = 0;
struct UnwindError {
#if defined(OPENSSL_WINDOWS)
crypto_word_t ip;
#endif
char str[512];
};
static UnwindError g_unwind_errors[kMaxUnwindErrors];
template <typename... Args>
static void AddUnwindError(UnwindCursor *cursor, Args... args) {
if (g_num_unwind_errors >= kMaxUnwindErrors) {
return;
}
#if defined(OPENSSL_WINDOWS)
// Windows symbol functions should not be called when handling an
// exception. Stash the instruction pointer, to be symbolized later.
g_unwind_errors[g_num_unwind_errors].ip = cursor->starting_ip();
StrCatSignalSafe(g_unwind_errors[g_num_unwind_errors].str, args...);
#else
StrCatSignalSafe(g_unwind_errors[g_num_unwind_errors].str,
"unwinding at ", cursor->ToString(), ": ", args...);
#endif
g_num_unwind_errors++;
}
static void CheckUnwind(UnwindCursor *cursor) {
const crypto_word_t kStartAddress =
reinterpret_cast<crypto_word_t>(&abi_test_unwind_start);
const crypto_word_t kReturnAddress =
reinterpret_cast<crypto_word_t>(&abi_test_unwind_return);
const crypto_word_t kStopAddress =
reinterpret_cast<crypto_word_t>(&abi_test_unwind_stop);
crypto_word_t sp = cursor->GetSP().ValueOrDie("Error getting stack pointer");
crypto_word_t ip =
cursor->GetIP().ValueOrDie("Error getting instruction pointer");
if (!g_in_trampoline) {
if (ip != kStartAddress) {
FatalError("Unexpected SIGTRAP at ", cursor->ToString());
}
// Save the current state and begin.
g_in_trampoline = true;
g_unwind_function_done = false;
g_trampoline_sp = sp;
g_trampoline_state = cursor->GetCallerState().ValueOrDie(
"Error getting initial caller state");
} else {
if (sp == g_trampoline_sp || g_unwind_function_done) {
// |g_unwind_function_done| should imply |sp| is |g_trampoline_sp|, but
// clearing the trap flag in x86 briefly displaces the stack pointer.
//
// Also note we check both |ip| and |sp| below, in case the function under
// test is also |abi_test_trampoline|.
if (ip == kReturnAddress && sp == g_trampoline_sp) {
g_unwind_function_done = true;
}
if (ip == kStopAddress && sp == g_trampoline_sp) {
// |SIGTRAP| is fatal again.
g_in_trampoline = false;
}
} else if (IsAncestorStackFrame(sp, g_trampoline_sp)) {
// This should never happen. We went past |g_trampoline_sp| without
// stopping at |kStopAddress|.
AddUnwindError(cursor, "stack frame is before caller");
g_in_trampoline = false;
} else if (g_num_unwind_errors < kMaxUnwindErrors) {
for (;;) {
UnwindStatusOr<bool> step_ret = cursor->Step();
if (!step_ret.ok()) {
AddUnwindError(cursor, "error unwinding: ", step_ret.Error());
break;
}
// |Step| returns whether there was a frame to unwind.
if (!step_ret.ValueOrDie()) {
AddUnwindError(cursor, "could not unwind to starting frame");
break;
}
UnwindStatusOr<crypto_word_t> cur_sp = cursor->GetSP();
if (!cur_sp.ok()) {
AddUnwindError(cursor,
"error recovering stack pointer: ", cur_sp.Error());
break;
}
if (IsAncestorStackFrame(cur_sp.ValueOrDie(), g_trampoline_sp)) {
AddUnwindError(cursor, "unwound past starting frame");
break;
}
if (cur_sp.ValueOrDie() == g_trampoline_sp) {
// We found the parent frame. Check the return address.
UnwindStatusOr<crypto_word_t> cur_ip = cursor->GetIP();
if (!cur_ip.ok()) {
AddUnwindError(cursor,
"error recovering return address: ", cur_ip.Error());
} else if (cur_ip.ValueOrDie() != kReturnAddress) {
AddUnwindError(cursor, "wrong return address");
}
// Check the remaining registers.
UnwindStatusOr<CallerState> state = cursor->GetCallerState();
if (!state.ok()) {
AddUnwindError(cursor,
"error recovering registers: ", state.Error());
} else {
ForEachMismatch(state.ValueOrDie(), g_trampoline_state,
[&](const char *reg) {
AddUnwindError(cursor, reg, " was not recovered");
});
}
break;
}
}
}
}
}
static void ReadUnwindResult(Result *out) {
for (size_t i = 0; i < g_num_unwind_errors; i++) {
#if defined(OPENSSL_WINDOWS)
const crypto_word_t ip = g_unwind_errors[i].ip;
char buf[256];
DWORD64 displacement;
struct {
SYMBOL_INFO info;
char name_buf[128];
} symbol;
memset(&symbol, 0, sizeof(symbol));
symbol.info.SizeOfStruct = sizeof(symbol.info);
symbol.info.MaxNameLen = sizeof(symbol.name_buf);
if (SymFromAddr(GetCurrentProcess(), ip, &displacement, &symbol.info)) {
snprintf(buf, sizeof(buf), "unwinding at %s+%llu (0x%s): %s",
symbol.info.Name, displacement, WordToHex(ip).data(),
g_unwind_errors[i].str);
} else {
snprintf(buf, sizeof(buf), "unwinding at 0x%s: %s",
WordToHex(ip).data(), g_unwind_errors[i].str);
}
out->errors.emplace_back(buf);
#else
out->errors.emplace_back(g_unwind_errors[i].str);
#endif
}
if (g_num_unwind_errors == kMaxUnwindErrors) {
out->errors.emplace_back("(additional errors omitted)");
}
g_num_unwind_errors = 0;
}
#if defined(OPENSSL_WINDOWS)
static DWORD g_main_thread;
static long ExceptionHandler(EXCEPTION_POINTERS *info) {
if (info->ExceptionRecord->ExceptionCode != EXCEPTION_SINGLE_STEP ||
GetCurrentThreadId() != g_main_thread) {
return EXCEPTION_CONTINUE_SEARCH;
}
UnwindCursor cursor(*info->ContextRecord);
CheckUnwind(&cursor);
if (g_in_trampoline) {
// Windows clears the trap flag, so we must restore it.
info->ContextRecord->EFlags |= 0x100;
}
return EXCEPTION_CONTINUE_EXECUTION;
}
static void EnableUnwindTestsImpl() {
if (IsDebuggerPresent()) {
// Unwind tests drive logic via |EXCEPTION_SINGLE_STEP|, which conflicts with
// debuggers.
fprintf(stderr, "Debugger detected. Disabling unwind tests.\n");
return;
}
g_main_thread = GetCurrentThreadId();
SymSetOptions(SYMOPT_DEFERRED_LOADS);
if (!SymInitialize(GetCurrentProcess(), nullptr, TRUE)) {
fprintf(stderr, "Could not initialize symbols.\n");
}
if (AddVectoredExceptionHandler(0, ExceptionHandler) == nullptr) {
fprintf(stderr, "Error installing exception handler.\n");
abort();
}
g_unwind_tests_enabled = true;
}
#else // !OPENSSL_WINDOWS
// HandleEINTR runs |func| and returns the result, retrying the operation on
// |EINTR|.
template <typename Func>
static auto HandleEINTR(const Func &func) -> decltype(func()) {
decltype(func()) ret;
do {
ret = func();
} while (ret < 0 && errno == EINTR);
return ret;
}
static bool ReadFileToString(std::string *out, const char *path) {
out->clear();
int fd = HandleEINTR([&] { return open(path, O_RDONLY); });
if (fd < 0) {
return false;
}
for (;;) {
char buf[1024];
ssize_t ret = HandleEINTR([&] { return read(fd, buf, sizeof(buf)); });
if (ret < 0) {
close(fd);
return false;
}
if (ret == 0) {
close(fd);
return true;
}
out->append(buf, static_cast<size_t>(ret));
}
}
static bool IsBeingDebugged() {
std::string status;
if (!ReadFileToString(&status, "/proc/self/status")) {
perror("error reading /proc/self/status");
return false;
}
std::string key = "\nTracerPid:\t";
size_t idx = status.find(key);
if (idx == std::string::npos) {
return false;
}
idx += key.size();
return idx < status.size() && status[idx] != '0';
}
static pthread_t g_main_thread;
static void TrapHandler(int sig) {
// Note this is a signal handler, so only async-signal-safe functions may be
// used here. See signal-safety(7). libunwind promises local unwind is
// async-signal-safe.
// |pthread_equal| is not listed as async-signal-safe, but this is clearly an
// oversight.
if (!pthread_equal(g_main_thread, pthread_self())) {
FatalError("SIGTRAP on background thread");
}
unw_context_t ctx;
int ret = unw_getcontext(&ctx);
if (ret < 0) {
FatalError("Error getting unwind context: ", unw_strerror(ret));
}
UnwindCursor cursor(&ctx);
CheckUnwind(&cursor);
}
static void EnableUnwindTestsImpl() {
if (IsBeingDebugged()) {
// Unwind tests drive logic via |SIGTRAP|, which conflicts with debuggers.
fprintf(stderr, "Debugger detected. Disabling unwind tests.\n");
return;
}
g_main_thread = pthread_self();
struct sigaction trap_action;
OPENSSL_memset(&trap_action, 0, sizeof(trap_action));
sigemptyset(&trap_action.sa_mask);
trap_action.sa_handler = TrapHandler;
if (sigaction(SIGTRAP, &trap_action, NULL) != 0) {
perror("sigaction");
abort();
}
g_unwind_tests_enabled = true;
}
#endif // OPENSSL_WINDOWS
#else // !SUPPORTS_UNWIND_TEST
#if defined(SUPPORTS_ABI_TEST)
static void ReadUnwindResult(Result *) {}
#endif
static void EnableUnwindTestsImpl() {}
#endif // SUPPORTS_UNWIND_TEST
} // namespace internal
void EnableUnwindTests() { internal::EnableUnwindTestsImpl(); }
bool UnwindTestsEnabled() { return internal::g_unwind_tests_enabled; }
} // namespace abi_test