/*

 * This file is part of PowerDNS or dnsdist.

 * Copyright -- PowerDNS.COM B.V. and its contributors

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of version 2 of the GNU General Public License as

 * published by the Free Software Foundation.

 *

 * In addition, for the avoidance of any doubt, permission is granted to

 * link this program with OpenSSL and to (re)distribute the binaries

 * produced as the result of such linking.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

 */

#ifdef HAVE_CONFIG_H

#include "config.h"

#endif

#include "utility.hh"

#include <cstring>

#include <fcntl.h>

#include <unistd.h>

#include <stdlib.h>

#include "pdnsexception.hh"

#include "logger.hh"

#include "logging.hh"

#include "misc.hh"

#include <pwd.h>

#include <grp.h>

#include <sys/types.h>

#include <sys/select.h>

#include "namespaces.hh"

// Connects to socket with timeout

int Utility::timed_connect( Utility::sock_t sock,

    const sockaddr *addr,

    Utility::socklen_t sockaddr_size,

    int timeout_sec,

    int timeout_usec )

{

  fd_set set;

  struct timeval timeout;

  int ret;

  timeout.tv_sec = timeout_sec;

  timeout.tv_usec = timeout_usec;

  FD_ZERO(&set);

  FD_SET(sock, &set);

  setNonBlocking(sock);

  if ((ret = connect (sock, addr, sockaddr_size)) < 0) {

    if (errno != EINPROGRESS)

      return ret;

  }

  ret = select(sock + 1, nullptr, &set, nullptr, &timeout);

  setBlocking(sock);

  return ret;

}

void Utility::setBindAny([[maybe_unused]] int af, [[maybe_unused]] sock_t sock)

{

  const int one = 1;

  (void) one; // avoids 'unused var' warning on systems that have none of the defines checked below

#ifdef IP_FREEBIND

  if (setsockopt(sock, IPPROTO_IP, IP_FREEBIND, &one, sizeof(one)) < 0) {

    int err = errno;

    SLOG(g_log<<Logger::Warning<<"Warning: IP_FREEBIND setsockopt failed: "<<stringerror(err)<<endl,

         g_slog->withName("runtime")->error(Logr::Warning, err, "Warning: IP_FREEBIND setsockopt failed"));

  }

#endif

#ifdef IP_BINDANY

  if (af == AF_INET)

    if (setsockopt(sock, IPPROTO_IP, IP_BINDANY, &one, sizeof(one)) < 0) {

      int err = errno;

      SLOG(g_log<<Logger::Warning<<"Warning: IP_BINDANY setsockopt failed: "<<stringerror(err)<<endl,

           g_slog->withName("runtime")->error(Logr::Warning, err, "Warning: IP_BINDANY setsockopt failed"));

    }

#endif

#ifdef IPV6_BINDANY

  if (af == AF_INET6) {

    if (setsockopt(sock, IPPROTO_IPV6, IPV6_BINDANY, &one, sizeof(one)) < 0) {

      int err = errno;

      SLOG(g_log<<Logger::Warning<<"Warning: IPV6_BINDANY setsockopt failed: "<<stringerror(err)<<endl,

           g_slog->withName("runtime")->error(Logr::Warning, err, "Warning: IPV6_BINDANY setsockopt failed"));

    }

  }

#endif

#ifdef SO_BINDANY

  if (setsockopt(sock, SOL_SOCKET, SO_BINDANY, &one, sizeof(one)) < 0) {

    int err = errno;

    SLOG(g_log<<Logger::Warning<<"Warning: SO_BINDANY setsockopt failed: "<<stringerror(err)<<endl,

         g_slog->withName("runtime")->error(Logr::Warning, err, "Warning: SO_BINDANY setsockopt failed"));

  }

#endif

}

unsigned int Utility::sleep(unsigned int sec)

{

  return ::sleep(sec);

}

void Utility::usleep(unsigned long usec)

{

  struct timespec ts;

  ts.tv_sec = usec / 1000000;

  ts.tv_nsec = (usec % 1000000) * 1000;

  // POSIX.1 recommends using nanosleep instead of usleep

  ::nanosleep(&ts, nullptr);

}

// Drops the program's group privileges.

void Utility::dropGroupPrivs( uid_t uid, gid_t gid )

{

  if(gid && gid != getegid()) {

    if(setgid(gid)<0) {

      int err = errno;

      SLOG(g_log<<Logger::Critical<<"Unable to set effective group id to "<<gid<<": "<<stringerror(err)<<endl,

           g_slog->withName("runtime")->error(Logr::Critical, err, "Unable to set effective group id", "gid", Logging::Loggable(gid)));

      exit(1);

    }

    else {

      SLOG(g_log<<Logger::Info<<"Set effective group id to "<<gid<<endl,

           g_slog->withName("runtime")->info(Logr::Info, "Set effective group id", "gid", Logging::Loggable(gid)));

    }

    struct passwd *pw=getpwuid(uid);

    if(!pw) {

      SLOG(g_log<<Logger::Warning<<"Unable to determine user name for uid "<<uid<<endl,

           g_slog->withName("runtime")->info(Logr::Warning, "Unable to determine user name", "uid", Logging::Loggable(uid)));

      if (setgroups(0, nullptr)<0) {

        int err = errno;

        SLOG(g_log<<Logger::Critical<<"Unable to drop supplementary gids: "<<stringerror(err)<<endl,

             g_slog->withName("runtime")->error(Logr::Critical, err, "Unable to drop supplementary gids"));

        exit(1);

      }

    } else {

      if (initgroups(pw->pw_name, gid)<0) {

        int err = errno;

        SLOG(g_log<<Logger::Critical<<"Unable to set supplementary groups: "<<stringerror(err)<<endl,

             g_slog->withName("runtime")->error(Logr::Critical, err, "Unable to set supplementary groups"));

        exit(1);

      }

    }

  }

}

// Drops the program's user privileges.

void Utility::dropUserPrivs( uid_t uid )

{

  if(uid && uid != geteuid()) {

    if(setuid(uid)<0) {

      int err = errno;

      SLOG(g_log<<Logger::Critical<<"Unable to set effective user id to "<<uid<<": "<<stringerror(err)<<endl,

           g_slog->withName("runtime")->error(Logr::Critical, err, "Unable to set effective user id", "uid", Logging::Loggable(uid)));

      exit(1);

    }

    else {

      SLOG(g_log<<Logger::Info<<"Set effective user id to "<<uid<<endl,

           g_slog->withName("runtime")->info(Logr::Info, "Set effective user", "uid", Logging::Loggable(uid)));

    }

  }

}

// Returns the current process id.

Utility::pid_t Utility::getpid( )

{

  return ::getpid();

}

// Returns the current time.

int Utility::gettimeofday( struct timeval *tv, void * /* tz */)

{

  return ::gettimeofday(tv, nullptr);

}

// Writes a vector.

int Utility::writev(int socket, const iovec *vector, size_t count )

{

  return ::writev(socket,vector,count);

}

/* this is cut and pasted from dietlibc, gratefully copied! */

static int isleap(int year) {

  /* every fourth year is a leap year except for century years that are

   * not divisible by 400. */

  return (!(year%4) && ((year%100) || !(year%400)));

}

time_t Utility::timegm(struct tm *const t)

{

  const static short spm[13] = /* days per month -- nonleap! */

  { 0,

    (31),

    (31+28),

    (31+28+31),

    (31+28+31+30),

    (31+28+31+30+31),

    (31+28+31+30+31+30),

    (31+28+31+30+31+30+31),

    (31+28+31+30+31+30+31+31),

    (31+28+31+30+31+30+31+31+30),

    (31+28+31+30+31+30+31+31+30+31),

    (31+28+31+30+31+30+31+31+30+31+30),

    (31+28+31+30+31+30+31+31+30+31+30+31),

  };

  time_t  day;

  time_t  i;

  time_t years = t->tm_year - 70;

  // We allow for some benign out-of-range values

  if (t->tm_sec>60) { t->tm_min += t->tm_sec/60; t->tm_sec%=60; }

  if (t->tm_min>60) { t->tm_hour += t->tm_min/60; t->tm_min%=60; }

  if (t->tm_hour>24) { t->tm_mday += t->tm_hour/24; t->tm_hour%=24; }

  if (t->tm_mon>11) { t->tm_year += t->tm_mon/12; t->tm_mon%=12; }

  while (t->tm_mday>spm[1+t->tm_mon]) {

    if (t->tm_mon==1 && isleap(t->tm_year+1900)) {

      if (t->tm_mon==31+29) break;

      --t->tm_mday;

    }

    t->tm_mday-=spm[t->tm_mon];

    ++t->tm_mon;

    if (t->tm_mon>11) { t->tm_mon=0; ++t->tm_year; }

  }

  if (t->tm_year < 70)

    return (time_t) -1;

  /* Days since 1970 is 365 * number of years + number of leap years since 1970 */

  day  = years * 365 + (years + 1) / 4;

  /* After 2100 we have to subtract 3 leap years for every 400 years

     This is not intuitive. Most mktime implementations do not support

     dates after 2059, anyway, so we might leave this out for its

     bloat. */

  if ((years -= 131) >= 0) {

    years /= 100;

    day -= (years >> 2) * 3 + 1;

    if ((years &= 3) == 3) years--;

    day -= years;

  }

  day += t->tm_yday = spm [t->tm_mon] + t->tm_mday-1 + ( isleap (t->tm_year+1900)  &  (t->tm_mon > 1) );

  /* day is now the number of days since 'Jan 1 1970' */

  i = 7;

  // coverity[store_truncates_time_t]

  t->tm_wday = (day + 4) % i;                        /* Sunday=0, Monday=1, ..., Saturday=6 */

  i = 24;

  day *= i;

  i = 60;

  return ((day + t->tm_hour) * i + t->tm_min) * i + t->tm_sec;

}