Commit 61cd8d98 authored by Alberto Miranda's avatar Alberto Miranda ♨️
Browse files

Resolve "Client aborts if timezone not correctly detected" 

Closes #74

See merge request !30
parents 99e3706f 61b5ee71

include/client/logging.hpp

+1 −1
Original line number Diff line number Diff line
@@ -417,7 +417,7 @@ struct logger { 
    int debug_verbosity_;

#endif



    const date::time_zone * const timezone_;

    const date::time_zone * timezone_;

};



// the following static functions can be used to interact

src/client/logging.cpp

+30 −21
Original line number Diff line number Diff line
@@ -240,7 +240,7 @@ logger::logger(const std::string& opts, 
               int verbosity

#endif

               ) :

    timezone_(date::current_zone()) {

    timezone_(nullptr) {



    /* use stderr by default */

    log_fd_ = 2;
@@ -273,6 +273,35 @@ logger::logger(const std::string& opts, 
        log_fd_ = fd;

    }



    // Finding the current timezone implies accessing OS files (i.e. syscalls),

    // but current_zone() doesn't actually retrieve the time zone but rather

    // provides a descriptor to it that is **atomically initialized** upon its

    // first use. Thus, if we don't force the initialization here, logging the

    // first intercepted syscall will produce a call to date::time_zone::init()

    // (under std::call_once) which internally ends up calling fopen(). Since

    // fopen() ends up calling sys_open(), we will need to generate another

    // timestamp for a system call log entry, which will attempt to call

    // date::time_zone::init() since the prior initialization (under the same

    // std::call_once) has not yet completed.

    //

    // Unfortunately, date::time_zone doesn't provide a function to prevent

    // this lazy initialization, therefore we force it by requesting

    // information from an arbitrary timepoint (January 1st 1970) which forces

    // the initialization. This doesn't do any actual work and could safely be

    // removed if the date API ends up providing this functionality.

    try {

        timezone_ = date::current_zone();

#ifdef GKFS_DEBUG_BUILD

        using namespace date;

        timezone_->get_info(date::sys_days{January/1/1970});

#endif // GKFS_DEBUG_BUILD

    }

    catch(const std::exception& ex) {

        // if timezone initialization fails, setting timezone_ to nullptr

        // makes format_timestamp_to() default to producing epoch timestamps

        timezone_ = nullptr;

    }



#ifdef GKFS_ENABLE_LOGGING

    const auto log_hermes_message = 

        [](const std::string& msg, hermes::log::level l, int severity,
@@ -351,26 +380,6 @@ logger::logger(const std::string& opts, 
    hermes::log::logger::register_callback(

            hermes::log::mercury, log_hg_message);



#ifdef GKFS_DEBUG_BUILD

    // Finding the current timezone implies accessing OS files (i.e. syscalls),

    // but current_zone() doesn't actually retrieve the time zone but rather

    // provides a descriptor to it that is **atomically initialized** upon its 

    // first use. Thus, if we don't force the initialization here, logging

    // the first intercepted syscall will produce a call to 

    // date::time_zone::init() (under std::call_once) which internally ends up 

    // calling fopen(). Since fopen() ends up calling sys_open(), we will need 

    // to generate another timestamp for a system call log entry, which will

    // attempt to call date::time_zone::init() since the prior initialization

    // (under the same std::call_once) has not yet completed.

    //

    // Unfortunately, date::time_zone doesn't provide a function to prevent

    // this lazy initialization, therefore we force it by requesting 

    // information from an arbitrary timepoint (January 1st 1970) which forces

    // the initialization. This doesn't do any actual work and could safely

    // be removed if the date API ends up providing this functionality.

    using namespace date;

    timezone_->get_info(date::sys_days{January/1/1970});

#endif // GKFS_DEBUG_BUILD

#endif // GKFS_ENABLE_LOGGING

}