SystemLinux.cpp

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* This software is distributed under the terms of the Apache version 2 licence,     *
* copied verbatim in the file "LICENSE".                                            *
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#include "SystemLinux.h"
#include <array>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cxxabi.h>
#include <memory>
#include <regex>
#include <sys/types.h>
#include <sys/utsname.h>
#include <unistd.h>
 
namespace System {
  namespace Linux {
 
    std::vector<std::string> cmdLineArgs() {
 
      // Open the file that we can get this information from:
      char fname[1024];
      ::sprintf( fname, "/proc/%d/cmdline", ::getpid() );
      FILE* cmdLine = ::fopen( fname, "r" );
 
      // The result object:
      std::vector<std::string> result;
 
      // Read the command line arguments from there:
      char cmd[1024];
      if ( cmdLine ) {
        long len = ::fread( cmd, sizeof( char ), sizeof( cmd ), cmdLine );
        if ( len > 0 ) {
          cmd[len] = 0;
          for ( char* token = cmd; token - cmd < len; token += ::strlen( token ) + 1 ) { result.push_back( token ); }
        }
        ::fclose( cmdLine );
      }
 
      return result;
    }
 
    std::string typeinfoName( const char* class_name ) {
 
      // Demangle the name:
      int  status;
      auto realname = std::unique_ptr<char, decltype( free )*>(
          abi::__cxa_demangle( class_name, nullptr, nullptr, &status ), std::free );
      if ( !realname ) return class_name;
 
      // Substitute the full type of std::string with "std::string"
      static const std::regex cxx11_string{
          "std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >( (?=>))?" };
      std::string result = std::regex_replace( realname.get(), cxx11_string, "std::string" );
 
      // Substitute ', ' with ','
      static const std::regex comma_space{ ", " };
      result = std::regex_replace( result, comma_space, "," );
 
      return result;
    }
 
    std::string hostName() {
 
      static const size_t           STRING_SIZE = 512;
      std::array<char, STRING_SIZE> hname;
      if ( ::gethostname( hname.data(), STRING_SIZE ) ) { return ""; }
 
      // According to the gethostname documentation, if a host name is too long
      // to fit into the array provided by the user, the call will truncate the
      // name to fit into the array, without adding a terminating null
      // character at the end, and will not signal an error to the caller.
      // While SUSv2 guarantees that "Host names are limited to 255 bytes", and
      // the limit to host names is in practice 64 characters on Linux, just to
      // be safe, the last character of the returned array is set to null
      // forecfully.
      hname.back() = '\0';
 
      return std::string( hname.data() );
    }
 
    std::string osName() {
 
      struct utsname ut;
      if ( ::uname( &ut ) ) { return "UNKNOWN Linux"; }
      return std::string( ut.sysname );
    }
 
    std::string osVersion() {
 
      struct utsname ut;
      if ( ::uname( &ut ) ) { return "UNKNOWN version"; }
      return std::string( ut.release );
    }
 
    std::string machineType() {
 
      struct utsname ut;
      if ( ::uname( &ut ) ) { return "UNKNOWN"; }
      return std::string( ut.machine );
    }
 
    std::string accountName() {
 
      const char* acct = ::getlogin();
      if ( !acct ) acct = ::getenv( "LOGNAME" );
      if ( !acct ) acct = ::getenv( "USER" );
 
      return ( acct ? acct : "UNKNOWN" );
    }
 
  } // namespace Linux
} // namespace System