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Copyright 2018-2020, Barcelona Supercomputing Center (BSC), Spain
Copyright 2015-2020, Johannes Gutenberg Universitaet Mainz, Germany
This software was partially supported by the
EC H2020 funded project NEXTGenIO (Project ID: 671951, www.nextgenio.eu).
This software was partially supported by the
ADA-FS project under the SPPEXA project funded by the DFG.
SPDX-License-Identifier: MIT
*/
#ifndef LIBGKFS_LOGGING_HPP
#define LIBGKFS_LOGGING_HPP
#include <libsyscall_intercept_hook_point.h>
#include <type_traits>
#include <boost/optional.hpp>
#include <client/make_array.hpp>
#include <client/syscalls.hpp>
#include <fmt/format.h>
#include <fmt/ostream.h>
#ifdef GKFS_DEBUG_BUILD
#include <bitset>
#endif
namespace gkfs {
namespace log {
enum class log_level : short {
print_syscalls = 1 << 0,
print_syscalls_entry = 1 << 1,
print_info = 1 << 2,
print_critical = 1 << 3,
print_errors = 1 << 4,
print_warnings = 1 << 5,
print_hermes = 1 << 6,
print_mercury = 1 << 7,
print_debug = 1 << 8,
// for internal use
print_none = 0,
print_all = print_syscalls | print_syscalls_entry | print_info |
print_critical | print_errors | print_warnings |
print_hermes | print_mercury | print_debug,
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print_most = print_all & ~print_syscalls_entry,
print_help = 1 << 10
};
inline constexpr log_level
operator&(log_level l1, log_level l2) {
return log_level(static_cast<short>(l1) &
static_cast<short>(l2));
}
inline constexpr log_level
operator|(log_level l1, log_level l2) {
return log_level(static_cast<short>(l1) |
static_cast<short>(l2));
}
inline constexpr log_level
operator^(log_level l1, log_level l2) {
return log_level(static_cast<short>(l1) ^
static_cast<short>(l2));
}
inline constexpr log_level
operator~(log_level l1) {
return log_level(~static_cast<short>(l1));
}
inline constexpr bool
operator!(log_level dm) {
return static_cast<short>(dm) == 0;
}
inline const log_level&
operator|=(log_level& l1, log_level l2) {
return l1 = l1 | l2;
}
inline const log_level&
operator&=(log_level& l1, log_level l2) {
return l1 = l1 & l2;
}
inline const log_level&
operator^=(log_level& l1, log_level l2) {
return l1 = l1 ^ l2;
}
static const auto constexpr syscall = log_level::print_syscalls;
static const auto constexpr syscall_at_entry = log_level::print_syscalls_entry;
static const auto constexpr info = log_level::print_info;
static const auto constexpr critical = log_level::print_critical;
static const auto constexpr error = log_level::print_errors;
static const auto constexpr warning = log_level::print_warnings;
static const auto constexpr hermes = log_level::print_hermes;
static const auto constexpr mercury = log_level::print_mercury;
static const auto constexpr debug = log_level::print_debug;
static const auto constexpr none = log_level::print_none;
static const auto constexpr most = log_level::print_most;
static const auto constexpr all = log_level::print_all;
static const auto constexpr help = log_level::print_help;
static const auto constexpr level_names =
util::make_array(
"syscall",
"syscall", // sycall_entry uses the same name as syscall
"info",
"critical",
"error",
"warning",
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"mercury",
"debug"
);
inline constexpr auto
lookup_level_name(log_level l) {
assert(l != log::none && l != log::help);
// since all log levels are powers of 2, we can find a name
// very efficiently by counting the number of trailing 0-bits in l
const auto i = __builtin_ctz(static_cast<short>(l));
assert(i >= 0 && static_cast<std::size_t>(i) < level_names.size());
return level_names.at(i);
}
// forward declaration
struct logger;
namespace detail {
template <typename Buffer>
static inline void
log_buffer(std::FILE* fp,
Buffer&& buffer) {
log_buffer(::fileno(fp), std::forward<Buffer>(buffer));
}
template <typename Buffer>
static inline void
log_buffer(int fd,
Buffer&& buffer) {
if(fd < 0) {
throw std::runtime_error("Invalid file descriptor");
}
::syscall_no_intercept(SYS_write, fd, buffer.data(), buffer.size());
}
static inline void
log_buffer(int fd,
const void* buffer,
std::size_t length) {
if(fd < 0) {
throw std::runtime_error("Invalid file descriptor");
}
::syscall_no_intercept(SYS_write, fd, buffer, length);
}
/**
* format_timestamp_to - safely format a timestamp for logging messages
*
* This function produes a timestamp that can be used to prefix logging
* messages. Since we are actively intercepting system calls, the formatting
* MUST NOT rely on internal system calls, otherwise we risk recursively
* calling ourselves for each syscall generated. Also, we cannot rely on
* the C formatting functions asctime, ctime, gmtime, localtime, mktime,
* asctime_r, ctime_r, gmtime_r, localtime_r, since they acquire a
* non-reentrant lock to determine the caller's timezone (yes, the assumedly
* reentrant *_r versions of the functions exhibit this problem as well,
* see https://sourceware.org/bugzilla/show_bug.cgi?id=16145). To solve this
* issue and still get readable timestamps, we determine and cache the
* timezone when the logger is created so that the lock is only held once, by
* one thread exactly, and we pass it as an argument whenever we need to
* format a timestamp. If no timezone is provided, we just format the epoch.
*
* NOTE: we use the date C++ library to query the timezone database and
* to format the timestamps.
*/
template <typename Buffer>
static inline void
format_timestamp_to(Buffer&& buffer,
const date::time_zone * const timezone = nullptr) {
struct ::timeval tv;
int rv = ::syscall_no_intercept(SYS_gettimeofday, &tv, NULL);
if(::syscall_error_code(rv) != 0) {
return;
}
date::sys_time<std::chrono::microseconds> now{
std::chrono::seconds{tv.tv_sec} +
std::chrono::microseconds{tv.tv_usec}};
if(!timezone) {
fmt::format_to(buffer, "[{}] ", now.time_since_epoch().count());
return;
}
fmt::format_to(buffer, "[{}] ",
date::zoned_time<std::chrono::microseconds>{timezone, now});
}
template <typename Buffer>
static inline void
format_syscall_info_to(Buffer&& buffer,
gkfs::syscall::info info) {
const auto ttid = syscall_no_intercept(SYS_gettid);
fmt::format_to(buffer, "[{}] [syscall] ", ttid);
char o;
char t;
switch(gkfs::syscall::origin(info)) {
case gkfs::syscall::from_internal_code:
o = 'i';
break;
case gkfs::syscall::from_external_code:
o = 'a';
break;
default:
o = '?';
break;
}
switch(gkfs::syscall::target(info)) {
case gkfs::syscall::to_hook:
t = 'h';
break;
case gkfs::syscall::to_kernel:
t = 'k';
break;
default:
t = '?';
break;
}
const std::array<char, 5> tmp = {'[', o, t, ']', ' '};
fmt::format_to(buffer, fmt::string_view(tmp.data(), tmp.size()));
}
} // namespace detail
enum { max_buffer_size = LIBGKFS_LOG_MESSAGE_SIZE };
struct static_buffer : public fmt::basic_memory_buffer<char, max_buffer_size> {
protected:
void grow(std::size_t size) override final;
};
struct logger {
logger(const std::string& opts,
const std::string& path,
#ifdef GKFS_DEBUG_BUILD
,
const std::string& filter,
int verbosity
~logger();
template <typename... Args>
inline void
log(log_level level,
const char * const func,
const int lineno,
Args&&... args) {
if(!(level & log_mask_)) {
return;
}
static_buffer buffer;
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detail::format_timestamp_to(buffer, timezone_);
fmt::format_to(buffer, "[{}] [{}] ",
::syscall_no_intercept(SYS_gettid),
lookup_level_name(level));
if(!!(level & log::debug)) {
fmt::format_to(buffer, "<{}():{}> ", func, lineno);
}
fmt::format_to(buffer, std::forward<Args>(args)...);
fmt::format_to(buffer, "\n");
detail::log_buffer(log_fd_, buffer);
}
inline int
log(log_level level,
const char *fmt,
va_list ap) {
if(!(level & log_mask_)) {
return 0;
}
// we use buffer views to compose the logging messages to
// avoid copying buffers as much as possible
struct buffer_view {
const void* addr;
std::size_t size;
};
// helper lambda to print an iterable of buffer_views
const auto log_buffer_views =
[this](const auto& buffers) {
std::size_t n = 0;
for(const auto& bv : buffers) {
if(bv.addr != nullptr) {
detail::log_buffer(log_fd_, bv.addr, bv.size);
n += bv.size;
}
}
return n;
};
static_buffer prefix;
detail::format_timestamp_to(prefix);
fmt::format_to(prefix, "[{}] [{}] ",
::syscall_no_intercept(SYS_gettid),
lookup_level_name(level));
char buffer[max_buffer_size];
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const int n = vsnprintf(buffer, sizeof(buffer), fmt, ap);
std::array<buffer_view, 3> buffers{};
int i = 0;
int m = 0;
const char* addr = buffer;
const char* p = nullptr;
while((p = std::strstr(addr, "\n")) != nullptr) {
buffers[0] = buffer_view{prefix.data(), prefix.size()};
buffers[1] = buffer_view{addr, static_cast<std::size_t>(p - addr) + 1};
m += log_buffer_views(buffers);
addr = p + 1;
++i;
}
// original line might not end with (or include) '\n'
if(buffer[n-1] != '\n') {
buffers[0] = buffer_view{prefix.data(), prefix.size()};
buffers[1] = buffer_view{addr, static_cast<std::size_t>(&buffer[n] - addr)};
buffers[2] = buffer_view{"\n", 1};
m += log_buffer_views(buffers);
}
return m;
}
template <typename... Args>
static inline void
log_message(std::FILE* fp, Args&&... args) {
log_message(::fileno(fp), std::forward<Args>(args)...);
}
template <typename... Args>
static inline void
log_message(int fd, Args&&... args) {
if(fd < 0) {
throw std::runtime_error("Invalid file descriptor");
}
static_buffer buffer;
fmt::format_to(buffer, std::forward<Args>(args)...);
fmt::format_to(buffer, "\n");
detail::log_buffer(fd, buffer);
}
void
log_syscall(syscall::info info,
const long syscall_number,
const long args[6],
boost::optional<long> result = boost::none);
static std::shared_ptr<logger>& global_logger() {
static std::shared_ptr<logger> s_global_logger;
return s_global_logger;
}
int log_fd_;
log_level log_mask_;
#ifdef GKFS_DEBUG_BUILD
std::bitset<512> filtered_syscalls_;
const date::time_zone * timezone_;
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};
// the following static functions can be used to interact
// with a globally registered logger instance
template <typename... Args>
static inline void
create_global_logger(Args&&... args) {
auto foo = std::make_shared<logger>(std::forward<Args>(args)...);
logger::global_logger() = foo;
}
static inline void
register_global_logger(logger&& lg) {
logger::global_logger() = std::make_shared<logger>(std::move(lg));
}
static inline std::shared_ptr<logger>&
get_global_logger() {
return logger::global_logger();
}
static inline void
destroy_global_logger() {
logger::global_logger().reset();
}
inline void
static_buffer::grow(std::size_t size) {
const auto logger = get_global_logger();
if(logger) {
logger->log_mask_ &= ~(syscall | syscall_at_entry);
}
std::fprintf(stderr,
"FATAL: message too long for gkfs::log::static_buffer, increase the size of\n"
"LIBGKFS_LOG_MESSAGE_SIZE in CMake or reduce the length of the offending "
"message.\n");
abort();
}
} // namespace log
} // namespace gkfs
#define LOG(XXX, ...) LOG_##XXX(__VA_ARGS__)
#define LOG_INFO(...) do {} while(0);
#define LOG_WARNING(...) do {} while(0);
#define LOG_ERROR(...) do {} while(0);
#define LOG_CRITICAL(...) do {} while(0);
#define LOG_HERMES(...) do {} while(0);
#define LOG_MERCURY(...) do {} while(0);
#define LOG_SYSCALL(...) do {} while(0);
#define LOG_DEBUG(...) do {} while(0);
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#define LOG_INFO(...) do { \
if(gkfs::log::get_global_logger()) { \
gkfs::log::get_global_logger()->log( \
gkfs::log::info, __func__, __LINE__, __VA_ARGS__); \
} \
} while(0);
#define LOG_WARNING(...) do { \
if(gkfs::log::get_global_logger()) { \
gkfs::log::get_global_logger()->log( \
gkfs::log::warning, __func__, __LINE__, __VA_ARGS__); \
} \
} while(0);
#define LOG_ERROR(...) do { \
if(gkfs::log::get_global_logger()) { \
gkfs::log::get_global_logger()->log( \
gkfs::log::error, __func__, __LINE__, __VA_ARGS__); \
} \
} while(0);
#define LOG_CRITICAL(...) do { \
if(gkfs::log::get_global_logger()) { \
gkfs::log::get_global_logger()->log( \
gkfs::log::critical, __func__, __LINE__, __VA_ARGS__); \
} \
} while(0);
#define LOG_HERMES(...) do { \
if(gkfs::log::get_global_logger()) { \
gkfs::log::get_global_logger()->log( \
gkfs::log::hermes, __func__, __LINE__, __VA_ARGS__); \
} \
} while(0);
#define LOG_MERCURY(...) do { \
if(gkfs::log::get_global_logger()) { \
gkfs::log::get_global_logger()->log( \
gkfs::log::mercury, __func__, __LINE__, __VA_ARGS__); \
} \
} while(0);
#ifdef GKFS_DEBUG_BUILD
#define LOG_SYSCALL(...) do { \
if(gkfs::log::get_global_logger()) { \
gkfs::log::get_global_logger()->log_syscall(__VA_ARGS__); \
} \
} while(0);
#define LOG_DEBUG(...) do { \
if(gkfs::log::get_global_logger()) { \
gkfs::log::get_global_logger()->log( \
gkfs::log::debug, __func__, __LINE__, __VA_ARGS__); \
} \
} while(0);
#else // ! GKFS_DEBUG_BUILD
#define LOG_SYSCALL(...) do {} while(0);
#define LOG_DEBUG(...) do {} while(0);
#endif // ! GKFS_DEBUG_BUILD
#endif // LIBGKFS_LOGGING_HPP