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|
/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
* Copyright (C) 2018, Google Inc.
*
* log.cpp - Logging infrastructure
*/
#include "libcamera/internal/log.h"
#include <array>
#if HAVE_BACKTRACE
#include <execinfo.h>
#endif
#include <fstream>
#include <iostream>
#include <list>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <time.h>
#include <unordered_set>
#include <libcamera/logging.h>
#include "libcamera/internal/thread.h"
#include "libcamera/internal/utils.h"
/**
* \file log.h
* \brief Logging infrastructure
*
* libcamera includes a logging infrastructure used through the library that
* allows inspection of internal operation in a user-configurable way. The log
* messages are grouped in categories that represent areas of libcamera, and
* output of messages for each category can be controlled by independent log
* levels.
*
* The levels are configurable through the LIBCAMERA_LOG_LEVELS environment
* variable that contains a comma-separated list of 'category:level' pairs.
*
* The category names are strings and can include a wildcard ('*') character at
* the end to match multiple categories.
*
* The level are either numeric values, or strings containing the log level
* name. The available log levels are DEBUG, INFO, WARN, ERROR and FATAL. Log
* message with a level higher than or equal to the configured log level for
* their category are output to the log, while other messages are silently
* discarded.
*
* By default log messages are output to stderr. They can be redirected to a log
* file by setting the LIBCAMERA_LOG_FILE environment variable to the name of
* the file. The file must be writable and is truncated if it exists. If any
* error occurs when opening the file, the file is ignored and the log is output
* to stderr.
*/
/**
* \file logging.h
* \brief Logging management
*
* API to change the logging output destination and log levels programatically.
*/
namespace libcamera {
static int log_severity_to_syslog(LogSeverity severity)
{
switch (severity) {
case LogDebug:
return LOG_DEBUG;
case LogInfo:
return LOG_INFO;
case LogWarning:
return LOG_WARNING;
case LogError:
return LOG_ERR;
case LogFatal:
return LOG_ALERT;
default:
return LOG_NOTICE;
}
}
static const char *log_severity_name(LogSeverity severity)
{
static const char *const names[] = {
"DEBUG",
" INFO",
" WARN",
"ERROR",
"FATAL",
};
if (static_cast<unsigned int>(severity) < std::size(names))
return names[severity];
else
return "UNKWN";
}
/**
* \brief Log output
*
* The LogOutput class models a log output destination
*/
class LogOutput
{
public:
LogOutput(const char *path);
LogOutput(std::ostream *stream);
LogOutput();
~LogOutput();
bool isValid() const;
void write(const LogMessage &msg);
void write(const std::string &msg);
private:
void writeSyslog(LogSeverity severity, const std::string &msg);
void writeStream(const std::string &msg);
std::ostream *stream_;
LoggingTarget target_;
};
/**
* \brief Construct a log output based on a file
* \param[in] path Full path to log file
*/
LogOutput::LogOutput(const char *path)
: target_(LoggingTargetFile)
{
stream_ = new std::ofstream(path);
}
/**
* \brief Construct a log output based on a stream
* \param[in] stream Stream to send log output to
*/
LogOutput::LogOutput(std::ostream *stream)
: stream_(stream), target_(LoggingTargetStream)
{
}
/**
* \brief Construct a log output to syslog
*/
LogOutput::LogOutput()
: stream_(nullptr), target_(LoggingTargetSyslog)
{
openlog("libcamera", LOG_PID, 0);
}
LogOutput::~LogOutput()
{
switch (target_) {
case LoggingTargetFile:
delete stream_;
break;
case LoggingTargetSyslog:
closelog();
break;
default:
break;
}
}
/**
* \brief Check if the log output is valid
* \return True if the log output is valid
*/
bool LogOutput::isValid() const
{
switch (target_) {
case LoggingTargetFile:
return stream_->good();
case LoggingTargetStream:
return stream_ != nullptr;
default:
return true;
}
}
/**
* \brief Write message to log output
* \param[in] msg Message to write
*/
void LogOutput::write(const LogMessage &msg)
{
std::string str;
switch (target_) {
case LoggingTargetSyslog:
str = std::string(log_severity_name(msg.severity())) + " "
+ msg.category().name() + " " + msg.fileInfo() + " "
+ msg.msg();
writeSyslog(msg.severity(), str);
break;
case LoggingTargetStream:
case LoggingTargetFile:
str = "[" + utils::time_point_to_string(msg.timestamp()) + "] ["
+ std::to_string(Thread::currentId()) + "] "
+ log_severity_name(msg.severity()) + " "
+ msg.category().name() + " " + msg.fileInfo() + " "
+ msg.msg();
writeStream(str);
break;
default:
break;
}
}
/**
* \brief Write string to log output
* \param[in] str String to write
*/
void LogOutput::write(const std::string &str)
{
switch (target_) {
case LoggingTargetSyslog:
writeSyslog(LogDebug, str);
break;
case LoggingTargetStream:
case LoggingTargetFile:
writeStream(str);
break;
default:
break;
}
}
void LogOutput::writeSyslog(LogSeverity severity, const std::string &str)
{
syslog(log_severity_to_syslog(severity), "%s", str.c_str());
}
void LogOutput::writeStream(const std::string &str)
{
stream_->write(str.c_str(), str.size());
stream_->flush();
}
/**
* \brief Message logger
*
* The Logger class handles log configuration.
*/
class Logger
{
public:
~Logger();
static Logger *instance();
void write(const LogMessage &msg);
void backtrace();
int logSetFile(const char *path);
int logSetStream(std::ostream *stream);
int logSetTarget(LoggingTarget target);
void logSetLevel(const char *category, const char *level);
private:
Logger();
void parseLogFile();
void parseLogLevels();
static LogSeverity parseLogLevel(const std::string &level);
friend LogCategory;
void registerCategory(LogCategory *category);
std::unordered_set<LogCategory *> categories_;
std::list<std::pair<std::string, LogSeverity>> levels_;
std::shared_ptr<LogOutput> output_;
};
/**
* \enum LoggingTarget
* \brief Log destination type
* \var LoggingTargetNone
* \brief No logging destination
* \sa Logger::logSetTarget
* \var LoggingTargetSyslog
* \brief Log to syslog
* \sa Logger::logSetTarget
* \var LoggingTargetFile
* \brief Log to file
* \sa Logger::logSetFile
* \var LoggingTargetStream
* \brief Log to stream
* \sa Logger::logSetStream
*/
/**
* \brief Direct logging to a file
* \param[in] path Full path to the log file
*
* This function directs the log output to the file identified by \a path. The
* previous log target, if any, is closed, and all new log messages will be
* written to the new log file.
*
* If the function returns an error, the log target is not changed.
*
* \return Zero on success, or a negative error code otherwise
*/
int logSetFile(const char *path)
{
return Logger::instance()->logSetFile(path);
}
/**
* \brief Direct logging to a stream
* \param[in] stream Stream to send log output to
*
* This function directs the log output to \a stream. The previous log target,
* if any, is closed, and all new log messages will be written to the new log
* stream.
*
* If the function returns an error, the log file is not changed
*
* \return Zero on success, or a negative error code otherwise.
*/
int logSetStream(std::ostream *stream)
{
return Logger::instance()->logSetStream(stream);
}
/**
* \brief Set the logging target
* \param[in] target Logging destination
*
* This function sets the logging output to the target specified by \a target.
* The allowed values of \a target are LoggingTargetNone and
* LoggingTargetSyslog. LoggingTargetNone will send the log output to nowhere,
* and LoggingTargetSyslog will send the log output to syslog. The previous
* log target, if any, is closed, and all new log messages will be written to
* the new log destination.
*
* LoggingTargetFile and LoggingTargetStream are not valid values for \a target.
* Use logSetFile() and logSetStream() instead, respectively.
*
* If the function returns an error, the log file is not changed.
*
* \return Zero on success, or a negative error code otherwise.
*/
int logSetTarget(LoggingTarget target)
{
return Logger::instance()->logSetTarget(target);
}
/**
* \brief Set the log level
* \param[in] category Logging category
* \param[in] level Log level
*
* This function sets the log level of \a category to \a level.
* \a level shall be one of the following strings:
* - "DEBUG"
* - "INFO"
* - "WARN"
* - "ERROR"
* - "FATAL"
*
* "*" is not a valid \a category for this function.
*/
void logSetLevel(const char *category, const char *level)
{
Logger::instance()->logSetLevel(category, level);
}
Logger::~Logger()
{
for (LogCategory *category : categories_)
delete category;
}
/**
* \brief Retrieve the logger instance
*
* The Logger is a singleton and can't be constructed manually. This function
* shall instead be used to retrieve the single global instance of the logger.
*
* \return The logger instance
*/
Logger *Logger::instance()
{
static Logger instance;
return &instance;
}
/**
* \brief Write a message to the configured logger output
* \param[in] msg The message object
*/
void Logger::write(const LogMessage &msg)
{
std::shared_ptr<LogOutput> output = std::atomic_load(&output_);
if (!output)
return;
output->write(msg);
}
/**
* \brief Write a backtrace to the log
*/
void Logger::backtrace()
{
#if HAVE_BACKTRACE
std::shared_ptr<LogOutput> output = std::atomic_load(&output_);
if (!output)
return;
void *buffer[32];
int num_entries = ::backtrace(buffer, std::size(buffer));
char **strings = backtrace_symbols(buffer, num_entries);
if (!strings)
return;
std::ostringstream msg;
msg << "Backtrace:" << std::endl;
/*
* Skip the first two entries that correspond to this method and
* ~LogMessage().
*/
for (int i = 2; i < num_entries; ++i)
msg << strings[i] << std::endl;
output->write(msg.str());
free(strings);
#endif
}
/**
* \brief Set the log file
* \param[in] path Full path to the log file
*
* \sa libcamera::logSetFile()
*
* \return Zero on success, or a negative error code otherwise.
*/
int Logger::logSetFile(const char *path)
{
std::shared_ptr<LogOutput> output = std::make_shared<LogOutput>(path);
if (!output->isValid())
return -EINVAL;
std::atomic_store(&output_, output);
return 0;
}
/**
* \brief Set the log stream
* \param[in] stream Stream to send log output to
*
* \sa libcamera::logSetStream()
*
* \return Zero on success, or a negative error code otherwise.
*/
int Logger::logSetStream(std::ostream *stream)
{
std::shared_ptr<LogOutput> output = std::make_shared<LogOutput>(stream);
std::atomic_store(&output_, output);
return 0;
}
/**
* \brief Set the log target
* \param[in] target Log destination
*
* \sa libcamera::logSetTarget()
*
* \return Zero on success, or a negative error code otherwise.
*/
int Logger::logSetTarget(enum LoggingTarget target)
{
std::shared_ptr<LogOutput> output;
switch (target) {
case LoggingTargetSyslog:
output = std::make_shared<LogOutput>();
std::atomic_store(&output_, output);
break;
case LoggingTargetNone:
output = nullptr;
std::atomic_store(&output_, std::shared_ptr<LogOutput>());
break;
default:
return -EINVAL;
}
return 0;
}
/**
* \brief Set the log level
* \param[in] category Logging category
* \param[in] level Log level
*
* \sa libcamera::logSetLevel()
*/
void Logger::logSetLevel(const char *category, const char *level)
{
LogSeverity severity = parseLogLevel(level);
if (severity == LogInvalid)
return;
for (LogCategory *c : categories_) {
if (!strcmp(c->name(), category)) {
c->setSeverity(severity);
break;
}
}
}
/**
* \brief Construct a logger
*/
Logger::Logger()
{
parseLogFile();
parseLogLevels();
}
/**
* \brief Parse the log output file from the environment
*
* If the LIBCAMERA_LOG_FILE environment variable is set, open the file it
* points to and redirect the logger output to it. If the environment variable
* is set to "syslog", then the logger output will be directed to syslog. Errors
* are silently ignored and don't affect the logger output (set to stderr).
*/
void Logger::parseLogFile()
{
const char *file = utils::secure_getenv("LIBCAMERA_LOG_FILE");
if (!file) {
logSetStream(&std::cerr);
return;
}
if (!strcmp(file, "syslog")) {
logSetTarget(LoggingTargetSyslog);
return;
}
logSetFile(file);
}
/**
* \brief Parse the log levels from the environment
*
* The log levels are stored in the LIBCAMERA_LOG_LEVELS environment variable
* as a list of "category:level" pairs, separated by commas (','). Parse the
* variable and store the levels to configure all log categories.
*/
void Logger::parseLogLevels()
{
const char *debug = utils::secure_getenv("LIBCAMERA_LOG_LEVELS");
if (!debug)
return;
for (const char *pair = debug; *debug != '\0'; pair = debug) {
const char *comma = strchrnul(debug, ',');
size_t len = comma - pair;
/* Skip over the comma. */
debug = *comma == ',' ? comma + 1 : comma;
/* Skip to the next pair if the pair is empty. */
if (!len)
continue;
std::string category;
std::string level;
const char *colon = static_cast<const char *>(memchr(pair, ':', len));
if (!colon) {
/* 'x' is a shortcut for '*:x'. */
category = "*";
level = std::string(pair, len);
} else {
category = std::string(pair, colon - pair);
level = std::string(colon + 1, comma - colon - 1);
}
/* Both the category and the level must be specified. */
if (category.empty() || level.empty())
continue;
LogSeverity severity = parseLogLevel(level);
if (severity == LogInvalid)
continue;
levels_.push_back({ category, severity });
}
}
/**
* \brief Parse a log level string into a LogSeverity
* \param[in] level The log level string
*
* Log levels can be specified as an integer value in the range from LogDebug to
* LogFatal, or as a string corresponding to the severity name in uppercase. Any
* other value is invalid.
*
* \return The log severity, or LogInvalid if the string is invalid
*/
LogSeverity Logger::parseLogLevel(const std::string &level)
{
static const char *const names[] = {
"DEBUG",
"INFO",
"WARN",
"ERROR",
"FATAL",
};
int severity;
if (std::isdigit(level[0])) {
char *endptr;
severity = strtoul(level.c_str(), &endptr, 10);
if (*endptr != '\0' || severity > LogFatal)
severity = LogInvalid;
} else {
severity = LogInvalid;
for (unsigned int i = 0; i < std::size(names); ++i) {
if (names[i] == level) {
severity = i;
break;
}
}
}
return static_cast<LogSeverity>(severity);
}
/**
* \brief Register a log category with the logger
* \param[in] category The log category
*
* Log categories must have unique names. If a category with the same name
* already exists this function performs no operation.
*/
void Logger::registerCategory(LogCategory *category)
{
categories_.insert(category);
const std::string &name = category->name();
for (const std::pair<std::string, LogSeverity> &level : levels_) {
bool match = true;
for (unsigned int i = 0; i < level.first.size(); ++i) {
if (level.first[i] == '*')
break;
if (i >= name.size() ||
name[i] != level.first[i]) {
match = false;
break;
}
}
if (match) {
category->setSeverity(level.second);
break;
}
}
}
/**
* \enum LogSeverity
* Log message severity
* \var LogDebug
* Debug message
* \var LogInfo
* Informational message
* \var LogWarning
* Warning message, signals a potential issue
* \var LogError
* Error message, signals an unrecoverable issue
* \var LogFatal
* Fatal message, signals an unrecoverable issue and aborts execution
*/
/**
* \class LogCategory
* \brief A category of log message
*
* The LogCategory class represents a category of log messages, related to an
* area of the library. It groups all messages belonging to the same category,
* and is used to control the log level per group.
*/
/**
* \brief Construct a log category
* \param[in] name The category name
*/
LogCategory::LogCategory(const char *name)
: name_(name), severity_(LogSeverity::LogInfo)
{
Logger::instance()->registerCategory(this);
}
/**
* \fn LogCategory::name()
* \brief Retrieve the log category name
* \return The log category name
*/
/**
* \fn LogCategory::severity()
* \brief Retrieve the severity of the log category
* \sa setSeverity()
* \return Return the severity of the log category
*/
/**
* \brief Set the severity of the log category
*
* Messages of severity higher than or equal to the severity of the log category
* are printed, other messages are discarded.
*/
void LogCategory::setSeverity(LogSeverity severity)
{
severity_ = severity;
}
/**
* \brief Retrieve the default log category
*
* The default log category is named "default" and is used by the LOG() macro
* when no log category is specified.
*
* \return A reference to the default log category
*/
const LogCategory &LogCategory::defaultCategory()
{
static const LogCategory *category = new LogCategory("default");
return *category;
}
/**
* \class LogMessage
* \brief Internal log message representation.
*
* The LogMessage class models a single message in the log. It serves as a
* helper to provide the std::ostream API for logging, and must never be used
* directly. Use the LOG() macro instead access the log infrastructure.
*/
/**
* \brief Construct a log message for a given category
* \param[in] fileName The file name where the message is logged from
* \param[in] line The line number where the message is logged from
* \param[in] category The log message category, controlling how the message
* will be displayed
* \param[in] severity The log message severity, controlling how the message
* will be displayed
*
* Create a log message pertaining to line \a line of file \a fileName. The
* \a severity argument sets the message severity to control whether it will be
* output or dropped.
*/
LogMessage::LogMessage(const char *fileName, unsigned int line,
const LogCategory &category, LogSeverity severity)
: category_(category), severity_(severity)
{
init(fileName, line);
}
/**
* \brief Move-construct a log message
* \param[in] other The other message
*
* The move constructor is meant to support the _log() functions. Thanks to copy
* elision it will likely never be called, but C++11 only permits copy elision,
* it doesn't enforce it unlike C++17. To avoid potential link errors depending
* on the compiler type and version, and optimization level, the move
* constructor is defined even if it will likely never be called, and ensures
* that the destructor of the \a other message will not output anything to the
* log by setting the severity to LogInvalid.
*/
LogMessage::LogMessage(LogMessage &&other)
: msgStream_(std::move(other.msgStream_)), category_(other.category_),
severity_(other.severity_)
{
other.severity_ = LogInvalid;
}
void LogMessage::init(const char *fileName, unsigned int line)
{
/* Log the timestamp, severity and file information. */
timestamp_ = utils::clock::now();
std::ostringstream ossFileInfo;
ossFileInfo << utils::basename(fileName) << ":" << line;
fileInfo_ = ossFileInfo.str();
}
LogMessage::~LogMessage()
{
/* Don't print anything if we have been moved to another LogMessage. */
if (severity_ == LogInvalid)
return;
msgStream_ << std::endl;
if (severity_ >= category_.severity())
Logger::instance()->write(*this);
if (severity_ == LogSeverity::LogFatal) {
Logger::instance()->backtrace();
std::abort();
}
}
/**
* \fn std::ostream& LogMessage::stream()
*
* Data is added to a LogMessage through the stream returned by this function.
* The stream implements the std::ostream API and can be used for logging as
* std::cout.
*
* \return A reference to the log message stream
*/
/**
* \fn LogMessage::timestamp()
* \brief Retrieve the timestamp of the log message
* \return The timestamp of the message
*/
/**
* \fn LogMessage::severity()
* \brief Retrieve the severity of the log message
* \return The severity of the message
*/
/**
* \fn LogMessage::category()
* \brief Retrieve the category of the log message
* \return The category of the message
*/
/**
* \fn LogMessage::fileInfo()
* \brief Retrieve the file info of the log message
* \return The file info of the message
*/
/**
* \fn LogMessage::msg()
* \brief Retrieve the message text of the log message
* \return The message text of the message, as a string
*/
/**
* \class Loggable
* \brief Base class to support log message extensions
*
* The Loggable class allows classes to extend log messages without any change
* to the way the LOG() macro is invoked. By inheriting from Loggable and
* implementing the logPrefix() virtual method, a class can specify extra
* information to be automatically added to messages logged from class member
* methods.
*/
Loggable::~Loggable()
{
}
/**
* \fn Loggable::logPrefix()
* \brief Retrieve a string to be prefixed to the log message
*
* This method allows classes inheriting from the Loggable class to extend the
* logger with an object-specific prefix output right before the log message
* contents.
*
* \return A string to be prefixed to the log message
*/
/**
* \brief Create a temporary LogMessage object to log a message
* \param[in] category The log message category
* \param[in] severity The log message severity
* \param[in] fileName The file name where the message is logged from
* \param[in] line The line number where the message is logged from
*
* This method is used as a backeng by the LOG() macro to create a log message
* for locations inheriting from the Loggable class.
*
* \return A log message
*/
LogMessage Loggable::_log(const LogCategory *category, LogSeverity severity,
const char *fileName, unsigned int line) const
{
LogMessage msg(fileName, line,
category ? *category : LogCategory::defaultCategory(),
severity);
msg.stream() << logPrefix() << ": ";
return msg;
}
/**
* \brief Create a temporary LogMessage object to log a message
* \param[in] category The log message category
* \param[in] severity The log message severity
* \param[in] fileName The file name where the message is logged from
* \param[in] line The line number where the message is logged from
*
* This function is used as a backeng by the LOG() macro to create a log
* message for locations not inheriting from the Loggable class.
*
* \return A log message
*/
LogMessage _log(const LogCategory *category, LogSeverity severity,
const char *fileName, unsigned int line)
{
return LogMessage(fileName, line,
category ? *category : LogCategory::defaultCategory(),
severity);
}
/**
* \def LOG_DECLARE_CATEGORY(name)
* \hideinitializer
* \brief Declare a category of log messages
*
* This macro is used to declare a log category defined in another compilation
* unit by the LOG_DEFINE_CATEGORY() macro.
*
* The LOG_DECLARE_CATEGORY() macro must be used in the libcamera namespace.
*
* \sa LogCategory
*/
/**
* \def LOG_DEFINE_CATEGORY(name)
* \hideinitializer
* \brief Define a category of log messages
*
* This macro is used to define a log category that can then be used with the
* LOGC() macro. Category names shall be unique, if a category is shared between
* compilation units, it shall be defined in one compilation unit only and
* declared with LOG_DECLARE_CATEGORY() in the other compilation units.
*
* The LOG_DEFINE_CATEGORY() macro must be used in the libcamera namespace.
*
* \sa LogCategory
*/
/**
* \def LOG(category, severity)
* \hideinitializer
* \brief Log a message
* \param[in] category Category (optional)
* \param[in] severity Severity
*
* Return an std::ostream reference to which a message can be logged using the
* iostream API. The \a category, if specified, sets the message category. When
* absent the default category is used. The \a severity controls whether the
* message is printed or discarded, depending on the log level for the category.
*
* If the severity is set to Fatal, execution is aborted and the program
* terminates immediately after printing the message.
*
* \warning Logging from the destructor of a global object, either directly or
* indirectly, results in undefined behaviour.
*
* \todo Allow logging from destructors of global objects to the largest
* possible extent
*/
/**
* \def ASSERT(condition)
* \hideinitializer
* \brief Abort program execution if assertion fails
*
* If \a condition is false, ASSERT() logs an error message with the Fatal log
* level and aborts program execution.
*
* If the macro NDEBUG is defined before including log.h, ASSERT() generates no
* code.
*
* Using conditions that have side effects with ASSERT() is not recommended, as
* these effects would depend on whether NDEBUG is defined or not. Similarly,
* ASSERT() should not be used to check for errors that can occur under normal
* conditions as those checks would then be removed when compiling with NDEBUG.
*/
} /* namespace libcamera */
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