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Diffstat (limited to 'third_party/abseil_cpp/absl/base/internal/raw_logging.cc')
| -rw-r--r-- | third_party/abseil_cpp/absl/base/internal/raw_logging.cc | 240 |
1 files changed, 240 insertions, 0 deletions
diff --git a/third_party/abseil_cpp/absl/base/internal/raw_logging.cc b/third_party/abseil_cpp/absl/base/internal/raw_logging.cc new file mode 100644 index 000000000000..40cea5506172 --- /dev/null +++ b/third_party/abseil_cpp/absl/base/internal/raw_logging.cc @@ -0,0 +1,240 @@ +// Copyright 2017 The Abseil Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#include "absl/base/internal/raw_logging.h" + +#include <stddef.h> +#include <cstdarg> +#include <cstdio> +#include <cstdlib> +#include <cstring> + +#include "absl/base/attributes.h" +#include "absl/base/config.h" +#include "absl/base/internal/atomic_hook.h" +#include "absl/base/log_severity.h" + +// We know how to perform low-level writes to stderr in POSIX and Windows. For +// these platforms, we define the token ABSL_LOW_LEVEL_WRITE_SUPPORTED. +// Much of raw_logging.cc becomes a no-op when we can't output messages, +// although a FATAL ABSL_RAW_LOG message will still abort the process. + +// ABSL_HAVE_POSIX_WRITE is defined when the platform provides posix write() +// (as from unistd.h) +// +// This preprocessor token is also defined in raw_io.cc. If you need to copy +// this, consider moving both to config.h instead. +#if defined(__linux__) || defined(__APPLE__) || defined(__FreeBSD__) || \ + defined(__Fuchsia__) || defined(__native_client__) || \ + defined(__EMSCRIPTEN__) || defined(__ASYLO__) + +#include <unistd.h> + +#define ABSL_HAVE_POSIX_WRITE 1 +#define ABSL_LOW_LEVEL_WRITE_SUPPORTED 1 +#else +#undef ABSL_HAVE_POSIX_WRITE +#endif + +// ABSL_HAVE_SYSCALL_WRITE is defined when the platform provides the syscall +// syscall(SYS_write, /*int*/ fd, /*char* */ buf, /*size_t*/ len); +// for low level operations that want to avoid libc. +#if (defined(__linux__) || defined(__FreeBSD__)) && !defined(__ANDROID__) +#include <sys/syscall.h> +#define ABSL_HAVE_SYSCALL_WRITE 1 +#define ABSL_LOW_LEVEL_WRITE_SUPPORTED 1 +#else +#undef ABSL_HAVE_SYSCALL_WRITE +#endif + +#ifdef _WIN32 +#include <io.h> + +#define ABSL_HAVE_RAW_IO 1 +#define ABSL_LOW_LEVEL_WRITE_SUPPORTED 1 +#else +#undef ABSL_HAVE_RAW_IO +#endif + +// TODO(gfalcon): We want raw-logging to work on as many platforms as possible. +// Explicitly #error out when not ABSL_LOW_LEVEL_WRITE_SUPPORTED, except for a +// whitelisted set of platforms for which we expect not to be able to raw log. + +ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES static absl::base_internal::AtomicHook< + absl::raw_logging_internal::LogPrefixHook> + log_prefix_hook; +ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES static absl::base_internal::AtomicHook< + absl::raw_logging_internal::AbortHook> + abort_hook; + +#ifdef ABSL_LOW_LEVEL_WRITE_SUPPORTED +static const char kTruncated[] = " ... (message truncated)\n"; + +// sprintf the format to the buffer, adjusting *buf and *size to reflect the +// consumed bytes, and return whether the message fit without truncation. If +// truncation occurred, if possible leave room in the buffer for the message +// kTruncated[]. +inline static bool VADoRawLog(char** buf, int* size, const char* format, + va_list ap) ABSL_PRINTF_ATTRIBUTE(3, 0); +inline static bool VADoRawLog(char** buf, int* size, + const char* format, va_list ap) { + int n = vsnprintf(*buf, *size, format, ap); + bool result = true; + if (n < 0 || n > *size) { + result = false; + if (static_cast<size_t>(*size) > sizeof(kTruncated)) { + n = *size - sizeof(kTruncated); // room for truncation message + } else { + n = 0; // no room for truncation message + } + } + *size -= n; + *buf += n; + return result; +} +#endif // ABSL_LOW_LEVEL_WRITE_SUPPORTED + +static constexpr int kLogBufSize = 3000; + +namespace { + +// CAVEAT: vsnprintf called from *DoRawLog below has some (exotic) code paths +// that invoke malloc() and getenv() that might acquire some locks. + +// Helper for RawLog below. +// *DoRawLog writes to *buf of *size and move them past the written portion. +// It returns true iff there was no overflow or error. +bool DoRawLog(char** buf, int* size, const char* format, ...) + ABSL_PRINTF_ATTRIBUTE(3, 4); +bool DoRawLog(char** buf, int* size, const char* format, ...) { + va_list ap; + va_start(ap, format); + int n = vsnprintf(*buf, *size, format, ap); + va_end(ap); + if (n < 0 || n > *size) return false; + *size -= n; + *buf += n; + return true; +} + +void RawLogVA(absl::LogSeverity severity, const char* file, int line, + const char* format, va_list ap) ABSL_PRINTF_ATTRIBUTE(4, 0); +void RawLogVA(absl::LogSeverity severity, const char* file, int line, + const char* format, va_list ap) { + char buffer[kLogBufSize]; + char* buf = buffer; + int size = sizeof(buffer); +#ifdef ABSL_LOW_LEVEL_WRITE_SUPPORTED + bool enabled = true; +#else + bool enabled = false; +#endif + +#ifdef ABSL_MIN_LOG_LEVEL + if (severity < static_cast<absl::LogSeverity>(ABSL_MIN_LOG_LEVEL) && + severity < absl::LogSeverity::kFatal) { + enabled = false; + } +#endif + + auto log_prefix_hook_ptr = log_prefix_hook.Load(); + if (log_prefix_hook_ptr) { + enabled = log_prefix_hook_ptr(severity, file, line, &buf, &size); + } else { + if (enabled) { + DoRawLog(&buf, &size, "[%s : %d] RAW: ", file, line); + } + } + const char* const prefix_end = buf; + +#ifdef ABSL_LOW_LEVEL_WRITE_SUPPORTED + if (enabled) { + bool no_chop = VADoRawLog(&buf, &size, format, ap); + if (no_chop) { + DoRawLog(&buf, &size, "\n"); + } else { + DoRawLog(&buf, &size, "%s", kTruncated); + } + absl::raw_logging_internal::SafeWriteToStderr(buffer, strlen(buffer)); + } +#else + static_cast<void>(format); + static_cast<void>(ap); +#endif + + // Abort the process after logging a FATAL message, even if the output itself + // was suppressed. + if (severity == absl::LogSeverity::kFatal) { + abort_hook(file, line, buffer, prefix_end, buffer + kLogBufSize); + abort(); + } +} + +} // namespace + +namespace absl { +ABSL_NAMESPACE_BEGIN +namespace raw_logging_internal { +void SafeWriteToStderr(const char *s, size_t len) { +#if defined(ABSL_HAVE_SYSCALL_WRITE) + syscall(SYS_write, STDERR_FILENO, s, len); +#elif defined(ABSL_HAVE_POSIX_WRITE) + write(STDERR_FILENO, s, len); +#elif defined(ABSL_HAVE_RAW_IO) + _write(/* stderr */ 2, s, len); +#else + // stderr logging unsupported on this platform + (void) s; + (void) len; +#endif +} + +void RawLog(absl::LogSeverity severity, const char* file, int line, + const char* format, ...) ABSL_PRINTF_ATTRIBUTE(4, 5); +void RawLog(absl::LogSeverity severity, const char* file, int line, + const char* format, ...) { + va_list ap; + va_start(ap, format); + RawLogVA(severity, file, line, format, ap); + va_end(ap); +} + +// Non-formatting version of RawLog(). +// +// TODO(gfalcon): When string_view no longer depends on base, change this +// interface to take its message as a string_view instead. +static void DefaultInternalLog(absl::LogSeverity severity, const char* file, + int line, const std::string& message) { + RawLog(severity, file, line, "%s", message.c_str()); +} + +bool RawLoggingFullySupported() { +#ifdef ABSL_LOW_LEVEL_WRITE_SUPPORTED + return true; +#else // !ABSL_LOW_LEVEL_WRITE_SUPPORTED + return false; +#endif // !ABSL_LOW_LEVEL_WRITE_SUPPORTED +} + +ABSL_DLL ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES + absl::base_internal::AtomicHook<InternalLogFunction> + internal_log_function(DefaultInternalLog); + +void RegisterInternalLogFunction(InternalLogFunction func) { + internal_log_function.Store(func); +} + +} // namespace raw_logging_internal +ABSL_NAMESPACE_END +} // namespace absl |