pdns/utility.hh

   1 /*
   2  * This file is part of PowerDNS or dnsdist.
   3  * Copyright -- PowerDNS.COM B.V. and its contributors
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of version 2 of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * In addition, for the avoidance of any doubt, permission is granted to
  10  * link this program with OpenSSL and to (re)distribute the binaries
  11  * produced as the result of such linking.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  21  */
  22 // Utility class specification.
  23 #pragma once
  24
  25 #ifdef NEED_POSIX_TYPEDEF
  26 typedef unsigned char uint8_t;
  27 typedef unsigned short int uint16_t;
  28 typedef unsigned int uint32_t;
  29 typedef unsigned long long uint64_t;
  30 #endif
  31
  32 #include <arpa/inet.h>
  33 #include <netinet/in.h>
  34 #include <sys/socket.h>
  35 #include <sys/time.h>
  36 #include <sys/uio.h>
  37 #include <csignal>
  38 #include <pthread.h>
  39 #include <semaphore.h>
  40 #include <csignal>
  41 #include <cerrno>
  42 #include <unistd.h>
  43 #include <string>
  44
  45 #include "namespaces.hh"
  46
  47 //! A semaphore class.
  48 class Semaphore
  49 {
  50 private:
  51   typedef int sem_value_t;
  52
  53 #if defined(_AIX) || defined(__APPLE__)
  54   uint32_t       m_magic;
  55   pthread_mutex_t m_lock;
  56   pthread_cond_t  m_gtzero;
  57   sem_value_t     m_count;
  58   uint32_t       m_nwaiters;
  59 #else
  60   std::unique_ptr<sem_t> m_pSemaphore;
  61 #endif
  62
  63 protected:
  64 public:
  65   Semaphore(const Semaphore&) = delete;
  66   void operator=(const Semaphore&) = delete;
  67   //! Default constructor.
  68   Semaphore( unsigned int value = 0 );
  69
  70   //! Destructor.
  71   ~Semaphore( void );
  72
  73   //! Posts to a semaphore.
  74   int post( void );
  75
  76   //! Waits for a semaphore.
  77   int wait( void );
  78
  79   //! Tries to wait for a semaphore.
  80   int tryWait( void );
  81
  82   //! Retrieves the semaphore value.
  83   int getValue( Semaphore::sem_value_t *sval );
  84 };
  85
  86 //! This is a utility class used for platform independent abstraction.
  87 class Utility
  88 {
  89 public:
  90   typedef ::iovec iovec;
  91   typedef ::pid_t pid_t;
  92   typedef int sock_t;
  93   typedef ::socklen_t socklen_t;
  94
  95   //! Connect with timeout
  96   // Returns:
  97   //    > 0 on success
  98   //    -1 on error
  99   //    0 on timeout
 100   static int timed_connect(sock_t sock,
 101     const sockaddr *addr,
 102     socklen_t sockaddr_size,
 103     int timeout_sec,
 104     int timeout_usec);
 105
 106   //! Returns the process id of the current process.
 107   static pid_t getpid( void );
 108
 109   //! Gets the current time.
 110   static int gettimeofday( struct timeval *tv, void *tz = NULL );
 111
 112   //! Converts an address from dot and numbers format to binary data.
 113   static int inet_aton( const char *cp, struct in_addr *inp );
 114
 115   //! Converts an address from presentation format to network format.
 116   static int inet_pton( int af, const char *src, void *dst );
 117
 118   //! The inet_ntop() function converts an address from network format (usually a struct in_addr or some other binary form, in network byte order) to presentation format.
 119   static const char *inet_ntop( int af, const char *src, char *dst, size_t size );
 120
 121   //! Writes a vector.
 122   static int writev( Utility::sock_t socket, const iovec *vector, size_t count );
 123
 124   //! Sets the random seed.
 125   static void srandom(void);
 126
 127   //! Drops the program's group privileges.
 128   static void dropGroupPrivs( uid_t uid, gid_t gid );
 129
 130   //! Drops the program's user privileges.
 131   static void dropUserPrivs( uid_t uid );
 132
 133   //! Sets the socket into Bind-any mode
 134   static void setBindAny ( int af, Utility::sock_t socket );
 135
 136   //! Sleeps for a number of seconds.
 137   static unsigned int sleep( unsigned int seconds );
 138
 139   //! Sleeps for a number of microseconds.
 140   static void usleep( unsigned long usec );
 141
 142   static time_t timegm(struct tm *tm);
 143
 144 };