tdlight/tdutils/td/utils/port/signals.cpp

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//
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// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2021
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#include "td/utils/port/signals.h"
#include "td/utils/port/config.h"
#include "td/utils/port/stacktrace.h"
#include "td/utils/port/StdStreams.h"
#include "td/utils/common.h"
#include "td/utils/format.h"
#if TD_PORT_POSIX
#include <signal.h>
#include <sys/mman.h>
#include <unistd.h>
#endif
#if TD_PORT_WINDOWS
#include <csignal>
#endif
#include <cerrno>
#include <cstdint>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <limits>
namespace td {
#if TD_PORT_POSIX && !TD_DARWIN_TV_OS && !TD_DARWIN_WATCH_OS
static Status protect_memory(void *addr, size_t len) {
if (mprotect(addr, len, PROT_NONE) != 0) {
return OS_ERROR("mprotect failed");
}
return Status::OK();
}
#endif
Status setup_signals_alt_stack() {
#if TD_PORT_POSIX && !TD_DARWIN_TV_OS && !TD_DARWIN_WATCH_OS
auto page_size = getpagesize();
auto stack_size = (MINSIGSTKSZ + 16 * page_size - 1) / page_size * page_size;
void *stack = mmap(nullptr, stack_size + 2 * page_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
if (stack == MAP_FAILED) {
return OS_ERROR("Mmap failed");
}
TRY_STATUS(protect_memory(stack, page_size));
TRY_STATUS(protect_memory(static_cast<char *>(stack) + stack_size + page_size, page_size));
stack_t signal_stack;
signal_stack.ss_sp = static_cast<char *>(stack) + page_size;
signal_stack.ss_size = stack_size;
signal_stack.ss_flags = 0;
if (sigaltstack(&signal_stack, nullptr) != 0) {
return OS_ERROR("sigaltstack failed");
}
#endif
return Status::OK();
}
#if TD_PORT_POSIX
static void set_handler(struct sigaction &act, decltype(act.sa_handler) handler) {
act.sa_handler = handler;
}
static void set_handler(struct sigaction &act, decltype(act.sa_sigaction) handler) {
act.sa_sigaction = handler;
act.sa_flags |= SA_SIGINFO;
}
template <class F>
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static Status set_signal_handler_impl(vector<int> &&signals, F func) {
struct sigaction act;
std::memset(&act, '\0', sizeof(act));
sigemptyset(&act.sa_mask);
for (auto signal : signals) {
sigaddset(&act.sa_mask, signal);
}
act.sa_flags = SA_RESTART | SA_ONSTACK;
set_handler(act, func);
for (auto signal : signals) {
if (sigaction(signal, &act, nullptr) != 0) {
return OS_ERROR("sigaction failed");
}
}
return Status::OK();
}
static vector<int> get_native_signals(SignalType type) {
switch (type) {
case SignalType::Abort:
return {SIGABRT, SIGXCPU, SIGXFSZ};
case SignalType::Error:
return {SIGILL, SIGFPE, SIGBUS, SIGSEGV, SIGSYS};
case SignalType::Quit:
return {SIGINT, SIGTERM, SIGQUIT};
case SignalType::Pipe:
return {SIGPIPE};
case SignalType::HangUp:
return {SIGHUP};
case SignalType::User:
return {SIGUSR1, SIGUSR2};
case SignalType::Other:
return {SIGTRAP, SIGALRM, SIGVTALRM, SIGPROF, SIGTSTP, SIGTTIN, SIGTTOU};
default:
return {};
}
}
#elif TD_PORT_WINDOWS
using signal_handler = void (*)(int sig);
static signal_handler signal_handlers[NSIG] = {};
static void signal_handler_func(int sig) {
std::signal(sig, signal_handler_func);
auto handler = signal_handlers[sig];
handler(sig);
}
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static Status set_signal_handler_impl(vector<int> &&signals, void (*func)(int sig)) {
for (auto signal : signals) {
CHECK(0 <= signal && signal < NSIG);
if (func != SIG_IGN && func != SIG_DFL) {
signal_handlers[signal] = func;
func = signal_handler_func;
}
if (std::signal(signal, func) == SIG_ERR) {
return Status::Error("Failed to set signal handler");
}
}
return Status::OK();
}
static vector<int> get_native_signals(SignalType type) {
switch (type) {
case SignalType::Abort:
return {SIGABRT};
case SignalType::Error:
return {SIGILL, SIGFPE, SIGSEGV};
case SignalType::Quit:
return {SIGINT, SIGTERM};
case SignalType::Pipe:
return {};
case SignalType::HangUp:
return {};
case SignalType::User:
return {};
case SignalType::Other:
return {};
default:
return {};
}
}
#endif
Status set_signal_handler(SignalType type, void (*func)(int sig)) {
return set_signal_handler_impl(get_native_signals(type), func == nullptr ? SIG_DFL : func);
}
using extended_signal_handler = void (*)(int sig, void *addr);
static extended_signal_handler extended_signal_handlers[NSIG] = {};
#if TD_PORT_POSIX
static void siginfo_handler(int signum, siginfo_t *info, void *data) {
auto handler = extended_signal_handlers[signum];
handler(signum, info->si_addr);
}
#elif TD_PORT_WINDOWS
static void siginfo_handler(int signum) {
auto handler = extended_signal_handlers[signum];
handler(signum, nullptr);
}
#endif
Status set_extended_signal_handler(SignalType type, extended_signal_handler func) {
CHECK(func != nullptr);
auto signals = get_native_signals(type);
for (auto signal : signals) {
if (0 <= signal && signal < NSIG) {
extended_signal_handlers[signal] = func;
} else {
UNREACHABLE();
}
}
return set_signal_handler_impl(std::move(signals), siginfo_handler);
}
Status set_runtime_signal_handler(int runtime_signal_number, void (*func)(int)) {
#ifdef SIGRTMIN
CHECK(SIGRTMIN + runtime_signal_number <= SIGRTMAX);
return set_signal_handler_impl({SIGRTMIN + runtime_signal_number}, func == nullptr ? SIG_DFL : func);
#else
return Status::OK();
#endif
}
Status ignore_signal(SignalType type) {
return set_signal_handler_impl(get_native_signals(type), SIG_IGN);
}
static void signal_safe_append_int(char **s, Slice name, int number) {
if (number < 0) {
number = std::numeric_limits<int>::max();
}
*--*s = ' ';
*--*s = ']';
do {
*--*s = static_cast<char>(number % 10 + '0');
number /= 10;
} while (number > 0);
*--*s = ' ';
for (auto pos = static_cast<int>(name.size()) - 1; pos >= 0; pos--) {
*--*s = name[pos];
}
*--*s = '[';
}
static void signal_safe_write_data(Slice data) {
#if TD_PORT_POSIX
while (!data.empty()) {
auto res = write(2, data.begin(), data.size());
if (res < 0 && errno == EINTR) {
continue;
}
if (res <= 0) {
break;
}
if (res > 0) {
data.remove_prefix(res);
}
}
#elif TD_PORT_WINDOWS
#if WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP | WINAPI_PARTITION_SYSTEM)
HANDLE stderr_handle = GetStdHandle(STD_ERROR_HANDLE);
DWORD bytes_written;
WriteFile(stderr_handle, data.data(), static_cast<DWORD>(data.size()), &bytes_written, nullptr);
#else
// there is no stderr
#endif
#endif
}
static int get_process_id() {
#if TD_PORT_POSIX
return getpid();
#elif TD_PORT_WINDOWS
return GetCurrentProcessId();
#endif
}
void signal_safe_write(Slice data, bool add_header) {
auto old_errno = errno;
if (add_header) {
constexpr size_t HEADER_BUF_SIZE = 100;
char header[HEADER_BUF_SIZE];
char *header_end = header + HEADER_BUF_SIZE;
char *header_begin = header_end;
signal_safe_append_int(&header_begin, "time", static_cast<int>(std::time(nullptr)));
signal_safe_append_int(&header_begin, "pid", get_process_id());
signal_safe_write_data(Slice(header_begin, header_end));
}
signal_safe_write_data(data);
errno = old_errno;
}
void signal_safe_write_signal_number(int sig, bool add_header) {
char buf[100];
char *end = buf + sizeof(buf);
char *ptr = end;
*--ptr = '\n';
do {
*--ptr = static_cast<char>(sig % 10 + '0');
sig /= 10;
} while (sig != 0);
ptr -= 8;
std::memcpy(ptr, "Signal: ", 8);
signal_safe_write(Slice(ptr, end), add_header);
}
void signal_safe_write_pointer(void *p, bool add_header) {
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auto addr = reinterpret_cast<std::uintptr_t>(p);
char buf[100];
char *end = buf + sizeof(buf);
char *ptr = end;
*--ptr = '\n';
do {
*--ptr = format::hex_digit(addr % 16);
addr /= 16;
} while (addr != 0);
*--ptr = 'x';
*--ptr = '0';
ptr -= 9;
std::memcpy(ptr, "Address: ", 9);
signal_safe_write(Slice(ptr, end), add_header);
}
static void block_stdin() {
#if TD_PORT_POSIX
Stdin().get_native_fd().set_is_blocking(true).ignore();
#endif
}
static void default_failure_signal_handler(int sig) {
Stacktrace::init();
signal_safe_write_signal_number(sig);
Stacktrace::PrintOptions options;
options.use_gdb = true;
Stacktrace::print_to_stderr(options);
block_stdin();
_Exit(EXIT_FAILURE);
}
Status set_default_failure_signal_handler() {
#if TD_PORT_POSIX
Stdin(); // init static variables before atexit
std::atexit(block_stdin);
#endif
TRY_STATUS(setup_signals_alt_stack());
TRY_STATUS(set_signal_handler(SignalType::Abort, default_failure_signal_handler));
TRY_STATUS(set_signal_handler(SignalType::Error, default_failure_signal_handler));
return Status::OK();
}
} // namespace td