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
  24 #ifndef UTILITY_HH
  25 #define UTILITY_HH
  26
  27 #ifdef NEED_POSIX_TYPEDEF
  28 typedef unsigned char uint8_t;
  29 typedef unsigned short int uint16_t;
  30 typedef unsigned int uint32_t;
  31 typedef unsigned long long uint64_t;
  32 #endif
  33
  34 #include <arpa/inet.h>
  35 #include <netinet/in.h>
  36 #include <sys/socket.h>
  37 #include <sys/time.h>
  38 #include <sys/uio.h>
  39 #include <signal.h>
  40 #include <pthread.h>
  41 #include <semaphore.h>
  42 #include <signal.h>
  43 #include <errno.h>
  44 #include <unistd.h>
  45 #include <string>
  46
  47 #include "namespaces.hh"
  48
  49 //! A semaphore class.
  50 class Semaphore
  51 {
  52 private:
  53   typedef int sem_value_t;
  54
  55 #if defined(_AIX) || defined(__APPLE__)
  56   uint32_t       m_magic;
  57   pthread_mutex_t m_lock;
  58   pthread_cond_t  m_gtzero;
  59   sem_value_t     m_count;
  60   uint32_t       m_nwaiters;
  61 #else
  62   sem_t *m_pSemaphore;
  63 #endif
  64
  65 protected:
  66 public:
  67   Semaphore(const Semaphore&) = delete;
  68   void operator=(const Semaphore&) = delete;
  69   //! Default constructor.
  70   Semaphore( unsigned int value = 0 );
  71
  72   //! Destructor.
  73   ~Semaphore( void );
  74
  75   //! Posts to a semaphore.
  76   int post( void );
  77
  78   //! Waits for a semaphore.
  79   int wait( void );
  80
  81   //! Tries to wait for a semaphore.
  82   int tryWait( void );
  83
  84   //! Retrieves the semaphore value.
  85   int getValue( Semaphore::sem_value_t *sval );
  86 };
  87
  88 //! This is a utility class used for platform independent abstraction.
  89 class Utility
  90 {
  91 public:
  92   typedef ::iovec iovec;
  93   typedef ::pid_t pid_t;
  94   typedef int sock_t;
  95   typedef ::socklen_t socklen_t;
  96
  97   //! Connect with timeout
  98   // Returns:
  99   //    > 0 on success
 100   //    -1 on error
 101   //    0 on timeout
 102   static int timed_connect(sock_t sock,
 103     const sockaddr *addr,
 104     socklen_t sockaddr_size,
 105     int timeout_sec,
 106     int timeout_usec);
 107
 108   //! Returns the process id of the current process.
 109   static pid_t getpid( void );
 110
 111   //! Gets the current time.
 112   static int gettimeofday( struct timeval *tv, void *tz = NULL );
 113
 114   //! Converts an address from dot and numbers format to binary data.
 115   static int inet_aton( const char *cp, struct in_addr *inp );
 116
 117   //! Converts an address from presentation format to network format.
 118   static int inet_pton( int af, const char *src, void *dst );
 119
 120   //! 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.
 121   static const char *inet_ntop( int af, const char *src, char *dst, size_t size );
 122
 123   //! Retrieves a gid using a groupname.
 124   static int makeGidNumeric( const string & group );
 125
 126   //! Retrieves an uid using an username.
 127   static int makeUidNumeric( const string & username );
 128
 129   //! Writes a vector.
 130   static int writev( Utility::sock_t socket, const iovec *vector, size_t count );
 131   //! Returns a random number.
 132   static long int random( void );
 133
 134   //! Sets the random seed.
 135   static void srandom( unsigned int seed );
 136
 137   //! Drops the program's group privileges.
 138   static void dropGroupPrivs( int uid, int gid );
 139
 140   //! Drops the program's user privileges.
 141   static void dropUserPrivs( int uid );
 142
 143   //! Sets the socket into Bind-any mode
 144   static void setBindAny ( int af, Utility::sock_t socket );
 145
 146   //! Sleeps for a number of seconds.
 147   static unsigned int sleep( unsigned int seconds );
 148
 149   //! Sleeps for a number of microseconds.
 150   static void usleep( unsigned long usec );
 151
 152   static time_t timegm(struct tm *tm);
 153
 154 };
 155
 156
 157 #endif // UTILITY_HH