pdns/unix_utility.cc

   1 /*
   2     PowerDNS Versatile Database Driven Nameserver
   3     Copyright (C) 2002 - 2011 PowerDNS.COM BV
   4
   5     This program is free software; you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License version 2 as
   7     published by the Free Software Foundation
   8
   9     Additionally, the license of this program contains a special
  10     exception which allows to distribute the program in binary form when
  11     it is linked against OpenSSL.
  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 St, Fifth Floor, Boston, MA  02110-1301  USA
  21 */
  22
  23 #ifdef HAVE_CONFIG_H
  24 #include "config.h"
  25 #endif
  26 #include "utility.hh"
  27 #include <cstring>
  28 #include <fcntl.h>
  29 #include <unistd.h>
  30 #include <stdlib.h>
  31 #include "pdnsexception.hh"
  32 #include "logger.hh"
  33 #include "misc.hh"
  34 #include <pwd.h>
  35 #include <grp.h>
  36 #include <sys/types.h>
  37 #include <sys/select.h>
  38
  39 #ifdef NEED_INET_NTOP_PROTO
  40 extern "C" {
  41 const char *inet_ntop(int af, const void *src, char *dst, size_t cnt);
  42 }
  43 #endif
  44
  45
  46 #include "namespaces.hh"
  47
  48
  49 // Connects to socket with timeout
  50 int Utility::timed_connect( Utility::sock_t sock,
  51     const sockaddr *addr,
  52     Utility::socklen_t sockaddr_size,
  53     int timeout_sec,
  54     int timeout_usec )
  55 {
  56   fd_set set;
  57   struct timeval timeout;
  58   int ret;
  59
  60   timeout.tv_sec = timeout_sec;
  61   timeout.tv_usec = timeout_usec;
  62
  63   FD_ZERO(&set);
  64   FD_SET(sock, &set);
  65
  66   setNonBlocking(sock);
  67
  68   if ((ret = connect (sock, addr, sockaddr_size)) < 0) {
  69     if (errno != EINPROGRESS)
  70       return ret;
  71   }
  72
  73   ret = select(sock + 1, NULL, &set, NULL, &timeout);
  74   setBlocking(sock);
  75
  76   return ret;
  77 }
  78
  79
  80
  81 void Utility::setBindAny(int af, sock_t sock)
  82 {
  83   const int one = 1;
  84
  85   (void) one; // avoids 'unused var' warning on systems that have none of the defines checked below
  86 #ifdef IP_FREEBIND
  87   if (setsockopt(sock, IPPROTO_IP, IP_FREEBIND, &one, sizeof(one)) < 0)
  88       theL()<<Logger::Warning<<"Warning: IP_FREEBIND setsockopt failed: "<<strerror(errno)<<endl;
  89 #endif
  90
  91 #ifdef IP_BINDANY
  92   if (af == AF_INET)
  93     if (setsockopt(sock, IPPROTO_IP, IP_BINDANY, &one, sizeof(one)) < 0)
  94       theL()<<Logger::Warning<<"Warning: IP_BINDANY setsockopt failed: "<<strerror(errno)<<endl;
  95 #endif
  96 #ifdef IPV6_BINDANY
  97   if (af == AF_INET6)
  98     if (setsockopt(sock, IPPROTO_IPV6, IPV6_BINDANY, &one, sizeof(one)) < 0)
  99       theL()<<Logger::Warning<<"Warning: IPV6_BINDANY setsockopt failed: "<<strerror(errno)<<endl;
 100 #endif
 101 #ifdef SO_BINDANY
 102   if (setsockopt(sock, SOL_SOCKET, SO_BINDANY, &one, sizeof(one)) < 0)
 103       theL()<<Logger::Warning<<"Warning: SO_BINDANY setsockopt failed: "<<strerror(errno)<<endl;
 104 #endif
 105 }
 106
 107 const char *Utility::inet_ntop(int af, const char *src, char *dst, size_t size)
 108 {
 109   return ::inet_ntop(af,src,dst,size);
 110 }
 111
 112 unsigned int Utility::sleep(unsigned int sec)
 113 {
 114   return ::sleep(sec);
 115 }
 116
 117 void Utility::usleep(unsigned long usec)
 118 {
 119   struct timespec ts;
 120   ts.tv_sec = usec / 1000000;
 121   ts.tv_nsec = (usec % 1000000) * 1000;
 122   // POSIX.1 recommends using nanosleep instead of usleep
 123   ::nanosleep(&ts, NULL);
 124 }
 125
 126
 127 // Drops the program's group privileges.
 128 void Utility::dropGroupPrivs( int uid, int gid )
 129 {
 130   if(gid) {
 131     if(setgid(gid)<0) {
 132       theL()<<Logger::Critical<<"Unable to set effective group id to "<<gid<<": "<<stringerror()<<endl;
 133       exit(1);
 134     }
 135     else
 136       theL()<<Logger::Info<<"Set effective group id to "<<gid<<endl;
 137
 138     struct passwd *pw=getpwuid(uid);
 139     if(!pw) {
 140       theL()<<Logger::Warning<<"Unable to determine user name for uid "<<uid<<endl;
 141       if (setgroups(0, NULL)<0) {
 142         theL()<<Logger::Critical<<"Unable to drop supplementary gids: "<<stringerror()<<endl;
 143         exit(1);
 144       }
 145     } else {
 146       if (initgroups(pw->pw_name, gid)<0) {
 147         theL()<<Logger::Critical<<"Unable to set supplementary groups: "<<stringerror()<<endl;
 148         exit(1);
 149       }
 150     }
 151   }
 152 }
 153
 154
 155 // Drops the program's user privileges.
 156 void Utility::dropUserPrivs( int uid )
 157 {
 158   if(uid) {
 159     if(setuid(uid)<0) {
 160       theL()<<Logger::Critical<<"Unable to set effective user id to "<<uid<<":  "<<stringerror()<<endl;
 161       exit(1);
 162     }
 163     else
 164       theL()<<Logger::Info<<"Set effective user id to "<<uid<<endl;
 165   }
 166 }
 167
 168
 169 // Returns the current process id.
 170 Utility::pid_t Utility::getpid( void )
 171 {
 172   return ::getpid();
 173 }
 174
 175
 176 // Returns the current time.
 177 int Utility::gettimeofday( struct timeval *tv, void *tz )
 178 {
 179   return ::gettimeofday(tv,0);
 180 }
 181
 182
 183
 184 // Retrieves a gid using a groupname.
 185 int Utility::makeGidNumeric(const string &group)
 186 {
 187   int newgid;
 188   if(!(newgid=atoi(group.c_str()))) {
 189     errno=0;
 190     struct group *gr=getgrnam(group.c_str());
 191     if(!gr) {
 192       theL()<<Logger::Critical<<"Unable to look up gid of group '"<<group<<"': "<< (errno ? strerror(errno) : "not found") <<endl;
 193       exit(1);
 194     }
 195     newgid=gr->gr_gid;
 196   }
 197   return newgid;
 198 }
 199
 200
 201 // Retrieves an uid using a username.
 202 int Utility::makeUidNumeric(const string &username)
 203 {
 204   int newuid;
 205   if(!(newuid=atoi(username.c_str()))) {
 206     struct passwd *pw=getpwnam(username.c_str());
 207     if(!pw) {
 208       theL()<<Logger::Critical<<"Unable to look up uid of user '"<<username<<"': "<< (errno ? strerror(errno) : "not found") <<endl;
 209       exit(1);
 210     }
 211     newuid=pw->pw_uid;
 212   }
 213   return newuid;
 214 }
 215
 216
 217 // Returns a random number.
 218 long int Utility::random( void )
 219 {
 220   return rand();
 221 }
 222
 223 // Sets the random seed.
 224 void Utility::srandom( unsigned int seed )
 225 {
 226   ::srandom(seed);
 227 }
 228
 229
 230 // Writes a vector.
 231 int Utility::writev(int socket, const iovec *vector, size_t count )
 232 {
 233   return ::writev(socket,vector,count);
 234 }
 235
 236 /* this is cut and pasted from dietlibc, gratefully copied! */
 237 static int isleap(int year) {
 238   /* every fourth year is a leap year except for century years that are
 239    * not divisible by 400. */
 240   return (!(year%4) && ((year%100) || !(year%400)));
 241 }
 242
 243 time_t Utility::timegm(struct tm *const t)
 244 {
 245   const static short spm[13] = /* days per month -- nonleap! */
 246   { 0,
 247     (31),
 248     (31+28),
 249     (31+28+31),
 250     (31+28+31+30),
 251     (31+28+31+30+31),
 252     (31+28+31+30+31+30),
 253     (31+28+31+30+31+30+31),
 254     (31+28+31+30+31+30+31+31),
 255     (31+28+31+30+31+30+31+31+30),
 256     (31+28+31+30+31+30+31+31+30+31),
 257     (31+28+31+30+31+30+31+31+30+31+30),
 258     (31+28+31+30+31+30+31+31+30+31+30+31),
 259   };
 260
 261   time_t  day;
 262   time_t  i;
 263   time_t years = t->tm_year - 70;
 264
 265   if (t->tm_sec>60) { t->tm_min += t->tm_sec/60; t->tm_sec%=60; }
 266   if (t->tm_min>60) { t->tm_hour += t->tm_min/60; t->tm_min%=60; }
 267   if (t->tm_hour>60) { t->tm_mday += t->tm_hour/60; t->tm_hour%=60; }
 268   if (t->tm_mon>11) { t->tm_year += t->tm_mon/12; t->tm_mon%=12; }
 269
 270   while (t->tm_mday>spm[1+t->tm_mon]) {
 271     if (t->tm_mon==1 && isleap(t->tm_year+1900)) {
 272       if (t->tm_mon==31+29) break;
 273       --t->tm_mday;
 274     }
 275     t->tm_mday-=spm[t->tm_mon];
 276     ++t->tm_mon;
 277     if (t->tm_mon>11) { t->tm_mon=0; ++t->tm_year; }
 278   }
 279
 280   if (t->tm_year < 70)
 281     return (time_t) -1;
 282   /* Days since 1970 is 365 * number of years + number of leap years since 1970 */
 283   day  = years * 365 + (years + 1) / 4;
 284
 285   /* After 2100 we have to subtract 3 leap years for every 400 years
 286      This is not intuitive. Most mktime implementations do not support
 287      dates after 2059, anyway, so we might leave this out for its
 288      bloat. */
 289   if ((years -= 131) >= 0) {
 290     years /= 100;
 291     day -= (years >> 2) * 3 + 1;
 292     if ((years &= 3) == 3) years--;
 293     day -= years;
 294   }
 295
 296   day += t->tm_yday = spm [t->tm_mon] + t->tm_mday-1 + ( isleap (t->tm_year+1900)  &  (t->tm_mon > 1) );
 297
 298   /* day is now the number of days since 'Jan 1 1970' */
 299   i = 7;
 300   t->tm_wday = (day + 4) % i;                        /* Sunday=0, Monday=1, ..., Saturday=6 */
 301
 302   i = 24;
 303   day *= i;
 304   i = 60;
 305   return ((day + t->tm_hour) * i + t->tm_min) * i + t->tm_sec;
 306 }
 307