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[thirdparty/chrony.git] / util.c

/*
  chronyd/chronyc - Programs for keeping computer clocks accurate.

 **********************************************************************
 * Copyright (C) Richard P. Curnow  1997-2003
 * Copyright (C) Miroslav Lichvar  2009, 2012-2018
 * 
 * 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.
 * 
 * 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.
 * 
 **********************************************************************

  =======================================================================

  Various utility functions
  */

#include "config.h"

#include "sysincl.h"

#include "logging.h"
#include "memory.h"
#include "util.h"
#include "hash.h"

#define NSEC_PER_SEC 1000000000

/* ================================================== */

void
UTI_ZeroTimespec(struct timespec *ts)
{
  ts->tv_sec = 0;
  ts->tv_nsec = 0;
}

/* ================================================== */

int
UTI_IsZeroTimespec(struct timespec *ts)
{
  return !ts->tv_sec && !ts->tv_nsec;
}

/* ================================================== */

void
UTI_TimevalToTimespec(const struct timeval *tv, struct timespec *ts)
{
  ts->tv_sec = tv->tv_sec;
  ts->tv_nsec = 1000 * tv->tv_usec;
}

/* ================================================== */

void
UTI_TimespecToTimeval(const struct timespec *ts, struct timeval *tv)
{
  tv->tv_sec = ts->tv_sec;
  tv->tv_usec = ts->tv_nsec / 1000;
}

/* ================================================== */

double
UTI_TimespecToDouble(const struct timespec *ts)
{
  return ts->tv_sec + 1.0e-9 * ts->tv_nsec;
}

/* ================================================== */

void
UTI_DoubleToTimespec(double d, struct timespec *ts)
{
  ts->tv_sec = d;
  ts->tv_nsec = 1.0e9 * (d - ts->tv_sec);
  UTI_NormaliseTimespec(ts);
}

/* ================================================== */

void
UTI_NormaliseTimespec(struct timespec *ts)
{
  if (ts->tv_nsec >= NSEC_PER_SEC || ts->tv_nsec < 0) {
    ts->tv_sec += ts->tv_nsec / NSEC_PER_SEC;
    ts->tv_nsec = ts->tv_nsec % NSEC_PER_SEC;

    /* If seconds are negative nanoseconds would end up negative too */
    if (ts->tv_nsec < 0) {
      ts->tv_sec--;
      ts->tv_nsec += NSEC_PER_SEC;
    }
  }
}

/* ================================================== */

double
UTI_TimevalToDouble(const struct timeval *tv)
{
  return tv->tv_sec + 1.0e-6 * tv->tv_usec;
}

/* ================================================== */

void
UTI_DoubleToTimeval(double a, struct timeval *b)
{
  double frac_part;

  b->tv_sec = a;
  frac_part = 1.0e6 * (a - b->tv_sec);
  b->tv_usec = frac_part > 0 ? frac_part + 0.5 : frac_part - 0.5;
  UTI_NormaliseTimeval(b);
}

/* ================================================== */

void
UTI_NormaliseTimeval(struct timeval *x)
{
  /* Reduce tv_usec to within +-1000000 of zero. JGH */
  if ((x->tv_usec >= 1000000) || (x->tv_usec <= -1000000)) {
    x->tv_sec += x->tv_usec/1000000;
    x->tv_usec = x->tv_usec%1000000;
  }

  /* Make tv_usec positive. JGH */
   if (x->tv_usec < 0) {
    --x->tv_sec;
    x->tv_usec += 1000000;
 }

}

/* ================================================== */

int
UTI_CompareTimespecs(const struct timespec *a, const struct timespec *b)
{
  if (a->tv_sec < b->tv_sec)
    return -1;
  if (a->tv_sec > b->tv_sec)
    return 1;
  if (a->tv_nsec < b->tv_nsec)
    return -1;
  if (a->tv_nsec > b->tv_nsec)
    return 1;
  return 0;
}

/* ================================================== */

void
UTI_DiffTimespecs(struct timespec *result, const struct timespec *a, const struct timespec *b)
{
  result->tv_sec = a->tv_sec - b->tv_sec;
  result->tv_nsec = a->tv_nsec - b->tv_nsec;
  UTI_NormaliseTimespec(result);
}

/* ================================================== */

/* Calculate result = a - b and return as a double */
double
UTI_DiffTimespecsToDouble(const struct timespec *a, const struct timespec *b)
{
  return ((double)a->tv_sec - (double)b->tv_sec) + 1.0e-9 * (a->tv_nsec - b->tv_nsec);
}

/* ================================================== */

void
UTI_AddDoubleToTimespec(const struct timespec *start, double increment, struct timespec *end)
{
  time_t int_part;

  int_part = increment;
  end->tv_sec = start->tv_sec + int_part;
  end->tv_nsec = start->tv_nsec + 1.0e9 * (increment - int_part);
  UTI_NormaliseTimespec(end);
}

/* ================================================== */

/* Calculate the average and difference (as a double) of two timespecs */
void
UTI_AverageDiffTimespecs(const struct timespec *earlier, const struct timespec *later,
                         struct timespec *average, double *diff)
{
  *diff = UTI_DiffTimespecsToDouble(later, earlier);
  UTI_AddDoubleToTimespec(earlier, *diff / 2.0, average);
}

/* ================================================== */

void
UTI_AddDiffToTimespec(const struct timespec *a, const struct timespec *b,
                      const struct timespec *c, struct timespec *result)
{
  double diff;

  diff = UTI_DiffTimespecsToDouble(a, b);
  UTI_AddDoubleToTimespec(c, diff, result);
}

/* ================================================== */

#define POOL_ENTRIES 16
#define BUFFER_LENGTH 64
static char buffer_pool[POOL_ENTRIES][BUFFER_LENGTH];
static int  pool_ptr = 0;

#define NEXT_BUFFER (buffer_pool[pool_ptr = ((pool_ptr + 1) % POOL_ENTRIES)])

/* ================================================== */
/* Convert a timespec into a temporary string, largely for diagnostic display */

char *
UTI_TimespecToString(const struct timespec *ts)
{
  char *result;

  result = NEXT_BUFFER;
#ifdef HAVE_LONG_TIME_T
  snprintf(result, BUFFER_LENGTH, "%"PRId64".%09lu",
           (int64_t)ts->tv_sec, (unsigned long)ts->tv_nsec);
#else
  snprintf(result, BUFFER_LENGTH, "%ld.%09lu",
           (long)ts->tv_sec, (unsigned long)ts->tv_nsec);
#endif
  return result;
}

/* ================================================== */
/* Convert an NTP timestamp into a temporary string, largely
   for diagnostic display */

char *
UTI_Ntp64ToString(const NTP_int64 *ntp_ts)
{
  struct timespec ts;
  UTI_Ntp64ToTimespec(ntp_ts, &ts);
  return UTI_TimespecToString(&ts);
}

/* ================================================== */

char *
UTI_RefidToString(uint32_t ref_id)
{
  unsigned int i, j, c;
  char *result;

  result = NEXT_BUFFER;

  for (i = j = 0; i < 4 && i < BUFFER_LENGTH - 1; i++) {
    c = (ref_id >> (24 - i * 8)) & 0xff;
    if (isprint(c))
      result[j++] = c;
  }

  result[j] = '\0';

  return result;
}

/* ================================================== */

char *
UTI_IPToString(const IPAddr *addr)
{
  unsigned long a, b, c, d, ip;
  const uint8_t *ip6;
  char *result;

  result = NEXT_BUFFER;
  switch (addr->family) {
    case IPADDR_UNSPEC:
      snprintf(result, BUFFER_LENGTH, "[UNSPEC]");
      break;
    case IPADDR_INET4:
      ip = addr->addr.in4;
      a = (ip>>24) & 0xff;
      b = (ip>>16) & 0xff;
      c = (ip>> 8) & 0xff;
      d = (ip>> 0) & 0xff;
      snprintf(result, BUFFER_LENGTH, "%lu.%lu.%lu.%lu", a, b, c, d);
      break;
    case IPADDR_INET6:
      ip6 = addr->addr.in6;
#ifdef FEAT_IPV6
      inet_ntop(AF_INET6, ip6, result, BUFFER_LENGTH);
#else
      assert(BUFFER_LENGTH >= 40);
      for (a = 0; a < 8; a++)
        snprintf(result + a * 5, 40 - a * 5, "%04x:",
                 (unsigned int)(ip6[2 * a] << 8 | ip6[2 * a + 1]));
#endif
      break;
    case IPADDR_ID:
      snprintf(result, BUFFER_LENGTH, "ID#%010"PRIu32, addr->addr.id);
      break;
    default:
      snprintf(result, BUFFER_LENGTH, "[UNKNOWN]");
  }
  return result;
}

/* ================================================== */

int
UTI_StringToIP(const char *addr, IPAddr *ip)
{
#ifdef FEAT_IPV6
  struct in_addr in4;
  struct in6_addr in6;

  if (inet_pton(AF_INET, addr, &in4) > 0) {
    ip->family = IPADDR_INET4;
    ip->_pad = 0;
    ip->addr.in4 = ntohl(in4.s_addr);
    return 1;
  }

  if (inet_pton(AF_INET6, addr, &in6) > 0) {
    ip->family = IPADDR_INET6;
    ip->_pad = 0;
    memcpy(ip->addr.in6, in6.s6_addr, sizeof (ip->addr.in6));
    return 1;
  }
#else
  unsigned long a, b, c, d, n;

  n = sscanf(addr, "%lu.%lu.%lu.%lu", &a, &b, &c, &d);
  if (n == 4) {
    ip->family = IPADDR_INET4;
    ip->_pad = 0;
    ip->addr.in4 = ((a & 0xff) << 24) | ((b & 0xff) << 16) | 
                   ((c & 0xff) << 8) | (d & 0xff);
    return 1;
  }
#endif

  return 0;
}

/* ================================================== */

int
UTI_StringToIdIP(const char *addr, IPAddr *ip)
{
  if (sscanf(addr, "ID#%"SCNu32, &ip->addr.id) == 1) {
    ip->family = IPADDR_ID;
    ip->_pad = 0;
    return 1;
  }

  return 0;
}

/* ================================================== */

int
UTI_IsIPReal(const IPAddr *ip)
{
  switch (ip->family) {
    case IPADDR_INET4:
    case IPADDR_INET6:
      return 1;
    default:
      return 0;
  }
}

/* ================================================== */

uint32_t
UTI_IPToRefid(const IPAddr *ip)
{
  static int MD5_hash = -1;
  unsigned char buf[16];

  switch (ip->family) {
    case IPADDR_INET4:
      return ip->addr.in4;
    case IPADDR_INET6:
      if (MD5_hash < 0)
        MD5_hash = HSH_GetHashId("MD5");

      if (MD5_hash < 0 ||
          HSH_Hash(MD5_hash, (const unsigned char *)ip->addr.in6, sizeof (ip->addr.in6),
                   NULL, 0, buf, sizeof (buf)) != sizeof (buf))
        LOG_FATAL("Could not get MD5");

      return (uint32_t)buf[0] << 24 | buf[1] << 16 | buf[2] << 8 | buf[3];
  }
  return 0;
}

/* ================================================== */

uint32_t
UTI_IPToHash(const IPAddr *ip)
{
  static uint32_t seed = 0;
  const unsigned char *addr;
  unsigned int i, len;
  uint32_t hash;

  switch (ip->family) {
    case IPADDR_INET4:
      addr = (unsigned char *)&ip->addr.in4;
      len = sizeof (ip->addr.in4);
      break;
    case IPADDR_INET6:
      addr = ip->addr.in6;
      len = sizeof (ip->addr.in6);
      break;
    case IPADDR_ID:
      addr = (unsigned char *)&ip->addr.id;
      len = sizeof (ip->addr.id);
      break;
    default:
      return 0;
  }

  /* Include a random seed in the hash to randomize collisions
     and order of addresses in hash tables */
  while (!seed)
    UTI_GetRandomBytes(&seed, sizeof (seed));

  for (i = 0, hash = seed; i < len; i++)
    hash = 71 * hash + addr[i];

  return hash + seed;
}

/* ================================================== */

void
UTI_IPHostToNetwork(const IPAddr *src, IPAddr *dest)
{
  /* Don't send uninitialized bytes over network */
  memset(dest, 0, sizeof (IPAddr));

  dest->family = htons(src->family);

  switch (src->family) {
    case IPADDR_INET4:
      dest->addr.in4 = htonl(src->addr.in4);
      break;
    case IPADDR_INET6:
      memcpy(dest->addr.in6, src->addr.in6, sizeof (dest->addr.in6));
      break;
    case IPADDR_ID:
      dest->addr.id = htonl(src->addr.id);
      break;
    default:
      dest->family = htons(IPADDR_UNSPEC);
  }
}

/* ================================================== */

void
UTI_IPNetworkToHost(const IPAddr *src, IPAddr *dest)
{
  dest->family = ntohs(src->family);
  dest->_pad = 0;

  switch (dest->family) {
    case IPADDR_INET4:
      dest->addr.in4 = ntohl(src->addr.in4);
      break;
    case IPADDR_INET6:
      memcpy(dest->addr.in6, src->addr.in6, sizeof (dest->addr.in6));
      break;
    case IPADDR_ID:
      dest->addr.id = ntohl(src->addr.id);
      break;
    default:
      dest->family = IPADDR_UNSPEC;
  }
}

/* ================================================== */

int
UTI_CompareIPs(const IPAddr *a, const IPAddr *b, const IPAddr *mask)
{
  int i, d;

  if (a->family != b->family)
    return a->family - b->family;

  if (mask && mask->family != b->family)
    mask = NULL;

  switch (a->family) {
    case IPADDR_UNSPEC:
      return 0;
    case IPADDR_INET4:
      if (mask)
        return (a->addr.in4 & mask->addr.in4) - (b->addr.in4 & mask->addr.in4);
      else
        return a->addr.in4 - b->addr.in4;
    case IPADDR_INET6:
      for (i = 0, d = 0; !d && i < 16; i++) {
        if (mask)
          d = (a->addr.in6[i] & mask->addr.in6[i]) -
              (b->addr.in6[i] & mask->addr.in6[i]);
        else
          d = a->addr.in6[i] - b->addr.in6[i];
      }
      return d;
    case IPADDR_ID:
      return a->addr.id - b->addr.id;
  }
  return 0;
}

/* ================================================== */

char *
UTI_IPSockAddrToString(const IPSockAddr *sa)
{
  char *result;

  result = NEXT_BUFFER;
  snprintf(result, BUFFER_LENGTH,
           sa->ip_addr.family != IPADDR_INET6 ? "%s:%hu" : "[%s]:%hu",
           UTI_IPToString(&sa->ip_addr), sa->port);

  return result;
}

/* ================================================== */

char *
UTI_TimeToLogForm(time_t t)
{
  struct tm *stm;
  char *result;

  result = NEXT_BUFFER;

  stm = gmtime(&t);

  if (stm)
    strftime(result, BUFFER_LENGTH, "%Y-%m-%d %H:%M:%S", stm);
  else
    snprintf(result, BUFFER_LENGTH, "INVALID    INVALID ");

  return result;
}

/* ================================================== */

void
UTI_AdjustTimespec(const struct timespec *old_ts, const struct timespec *when,
                   struct timespec *new_ts, double *delta_time, double dfreq, double doffset)
{
  double elapsed;

  elapsed = UTI_DiffTimespecsToDouble(when, old_ts);
  *delta_time = elapsed * dfreq - doffset;
  UTI_AddDoubleToTimespec(old_ts, *delta_time, new_ts);
}

/* ================================================== */

void
UTI_GetNtp64Fuzz(NTP_int64 *ts, int precision)
{
  int start, bits;

  assert(precision >= -32 && precision <= 32);
  assert(sizeof (*ts) == 8);

  start = sizeof (*ts) - (precision + 32 + 7) / 8;
  ts->hi = ts->lo = 0;

  UTI_GetRandomBytes((unsigned char *)ts + start, sizeof (*ts) - start);

  bits = (precision + 32) % 8;
  if (bits)
    ((unsigned char *)ts)[start] %= 1U << bits;
}

/* ================================================== */

double
UTI_Ntp32ToDouble(NTP_int32 x)
{
  return (double) ntohl(x) / 65536.0;
}

/* ================================================== */

#define MAX_NTP_INT32 (4294967295.0 / 65536.0)

NTP_int32
UTI_DoubleToNtp32(double x)
{
  NTP_int32 r;

  if (x >= MAX_NTP_INT32) {
    r = 0xffffffff;
  } else if (x <= 0.0) {
    r = 0;
  } else {
    x *= 65536.0;
    r = x;

    /* Round up */
    if (r < x)
      r++;
  }

  return htonl(r);
}

/* ================================================== */

void
UTI_ZeroNtp64(NTP_int64 *ts)
{
  ts->hi = ts->lo = htonl(0);
}

/* ================================================== */

int
UTI_IsZeroNtp64(const NTP_int64 *ts)
{
  return !ts->hi && !ts->lo;
}

/* ================================================== */

int
UTI_CompareNtp64(const NTP_int64 *a, const NTP_int64 *b)
{
  int32_t diff;

  if (a->hi == b->hi && a->lo == b->lo)
    return 0;

  diff = ntohl(a->hi) - ntohl(b->hi);

  if (diff < 0)
    return -1;
  if (diff > 0)
    return 1;

  return ntohl(a->lo) < ntohl(b->lo) ? -1 : 1;
}

/* ================================================== */

int
UTI_IsEqualAnyNtp64(const NTP_int64 *a, const NTP_int64 *b1, const NTP_int64 *b2,
                    const NTP_int64 *b3)
{
  if (b1 && a->lo == b1->lo && a->hi == b1->hi)
    return 1;

  if (b2 && a->lo == b2->lo && a->hi == b2->hi)
    return 1;

  if (b3 && a->lo == b3->lo && a->hi == b3->hi)
    return 1;

  return 0;
}

/* ================================================== */

/* Seconds part of NTP timestamp correponding to the origin of the time_t format */
#define JAN_1970 0x83aa7e80UL

#define NSEC_PER_NTP64 4.294967296

void
UTI_TimespecToNtp64(const struct timespec *src, NTP_int64 *dest, const NTP_int64 *fuzz)
{
  uint32_t hi, lo, sec, nsec;

  sec = (uint32_t)src->tv_sec;
  nsec = (uint32_t)src->tv_nsec;

  /* Recognize zero as a special case - it always signifies
     an 'unknown' value */
  if (!nsec && !sec) {
    hi = lo = 0;
  } else {
    hi = htonl(sec + JAN_1970);
    lo = htonl(NSEC_PER_NTP64 * nsec);

    /* Add the fuzz */
    if (fuzz) {
      hi ^= fuzz->hi;
      lo ^= fuzz->lo;
    }
  }

  dest->hi = hi;
  dest->lo = lo;
}

/* ================================================== */

void
UTI_Ntp64ToTimespec(const NTP_int64 *src, struct timespec *dest)
{
  uint32_t ntp_sec, ntp_frac;

  /* Zero is a special value */
  if (UTI_IsZeroNtp64(src)) {
    UTI_ZeroTimespec(dest);
    return;
  }

  ntp_sec = ntohl(src->hi);
  ntp_frac = ntohl(src->lo);

#ifdef HAVE_LONG_TIME_T
  dest->tv_sec = ntp_sec - (uint32_t)(NTP_ERA_SPLIT + JAN_1970) +
                 (time_t)NTP_ERA_SPLIT;
#else
  dest->tv_sec = ntp_sec - JAN_1970;
#endif

  dest->tv_nsec = ntp_frac / NSEC_PER_NTP64;
}

/* ================================================== */

/* Maximum offset between two sane times */
#define MAX_OFFSET 4294967296.0

/* Minimum allowed distance from maximum 32-bit time_t */
#define MIN_ENDOFTIME_DISTANCE (365 * 24 * 3600)

int
UTI_IsTimeOffsetSane(const struct timespec *ts, double offset)
{
  double t;

  /* Handle nan correctly here */
  if (!(offset > -MAX_OFFSET && offset < MAX_OFFSET))
    return 0;

  t = UTI_TimespecToDouble(ts) + offset;

  /* Time before 1970 is not considered valid */
  if (t < 0.0)
    return 0;

#ifdef HAVE_LONG_TIME_T
  /* Check if it's in the interval to which NTP time is mapped */
  if (t < (double)NTP_ERA_SPLIT || t > (double)(NTP_ERA_SPLIT + (1LL << 32)))
    return 0;
#else
  /* Don't get too close to 32-bit time_t overflow */
  if (t > (double)(0x7fffffff - MIN_ENDOFTIME_DISTANCE))
    return 0;
#endif

  return 1;
}

/* ================================================== */

double
UTI_Log2ToDouble(int l)
{
  if (l >= 0) {
    if (l > 31)
      l = 31;
    return (uint32_t)1 << l;
  } else {
    if (l < -31)
      l = -31;
    return 1.0 / ((uint32_t)1 << -l);
  }
}

/* ================================================== */

void
UTI_TimespecNetworkToHost(const Timespec *src, struct timespec *dest)
{
  uint32_t sec_low, nsec;
#ifdef HAVE_LONG_TIME_T
  uint32_t sec_high;
#endif

  sec_low = ntohl(src->tv_sec_low);
#ifdef HAVE_LONG_TIME_T
  sec_high = ntohl(src->tv_sec_high);
  if (sec_high == TV_NOHIGHSEC)
    sec_high = 0;

  dest->tv_sec = (uint64_t)sec_high << 32 | sec_low;
#else
  dest->tv_sec = sec_low;
#endif

  nsec = ntohl(src->tv_nsec);
  dest->tv_nsec = MIN(nsec, 999999999U);
}

/* ================================================== */

void
UTI_TimespecHostToNetwork(const struct timespec *src, Timespec *dest)
{
  dest->tv_nsec = htonl(src->tv_nsec);
#ifdef HAVE_LONG_TIME_T
  dest->tv_sec_high = htonl((uint64_t)src->tv_sec >> 32);
#else
  dest->tv_sec_high = htonl(TV_NOHIGHSEC);
#endif
  dest->tv_sec_low = htonl(src->tv_sec);
}

/* ================================================== */

#define FLOAT_EXP_BITS 7
#define FLOAT_EXP_MIN (-(1 << (FLOAT_EXP_BITS - 1)))
#define FLOAT_EXP_MAX (-FLOAT_EXP_MIN - 1)
#define FLOAT_COEF_BITS ((int)sizeof (int32_t) * 8 - FLOAT_EXP_BITS)
#define FLOAT_COEF_MIN (-(1 << (FLOAT_COEF_BITS - 1)))
#define FLOAT_COEF_MAX (-FLOAT_COEF_MIN - 1)

double
UTI_FloatNetworkToHost(Float f)
{
  int32_t exp, coef;
  uint32_t x;

  x = ntohl(f.f);

  exp = x >> FLOAT_COEF_BITS;
  if (exp >= 1 << (FLOAT_EXP_BITS - 1))
      exp -= 1 << FLOAT_EXP_BITS;
  exp -= FLOAT_COEF_BITS;

  coef = x % (1U << FLOAT_COEF_BITS);
  if (coef >= 1 << (FLOAT_COEF_BITS - 1))
      coef -= 1 << FLOAT_COEF_BITS;

  return coef * pow(2.0, exp);
}

Float
UTI_FloatHostToNetwork(double x)
{
  int32_t exp, coef, neg;
  Float f;

  if (x < 0.0) {
    x = -x;
    neg = 1;
  } else if (x >= 0.0) {
    neg = 0;
  } else {
    /* Save NaN as zero */
    x = 0.0;
    neg = 0;
  }

  if (x < 1.0e-100) {
    exp = coef = 0;
  } else if (x > 1.0e100) {
    exp = FLOAT_EXP_MAX;
    coef = FLOAT_COEF_MAX + neg;
  } else {
    exp = log(x) / log(2) + 1;
    coef = x * pow(2.0, -exp + FLOAT_COEF_BITS) + 0.5;

    assert(coef > 0);

    /* we may need to shift up to two bits down */
    while (coef > FLOAT_COEF_MAX + neg) {
      coef >>= 1;
      exp++;
    }

    if (exp > FLOAT_EXP_MAX) {
      /* overflow */
      exp = FLOAT_EXP_MAX;
      coef = FLOAT_COEF_MAX + neg;
    } else if (exp < FLOAT_EXP_MIN) {
      /* underflow */
      if (exp + FLOAT_COEF_BITS >= FLOAT_EXP_MIN) {
        coef >>= FLOAT_EXP_MIN - exp;
        exp = FLOAT_EXP_MIN;
      } else {
        exp = coef = 0;
      }
    }
  }

  /* negate back */
  if (neg)
    coef = (uint32_t)-coef << FLOAT_EXP_BITS >> FLOAT_EXP_BITS;

  f.f = htonl((uint32_t)exp << FLOAT_COEF_BITS | coef);
  return f;
}

/* ================================================== */

int
UTI_FdSetCloexec(int fd)
{
  int flags;

  flags = fcntl(fd, F_GETFD);
  if (flags == -1) {
    DEBUG_LOG("fcntl() failed : %s", strerror(errno));
    return 0;
  }

  flags |= FD_CLOEXEC;

  if (fcntl(fd, F_SETFD, flags) < 0) {
    DEBUG_LOG("fcntl() failed : %s", strerror(errno));
    return 0;
  }

  return 1;
}

/* ================================================== */

void
UTI_SetQuitSignalsHandler(void (*handler)(int), int ignore_sigpipe)
{
  struct sigaction sa;

  sa.sa_handler = handler;
  sa.sa_flags = SA_RESTART;
  if (sigemptyset(&sa.sa_mask) < 0)
    LOG_FATAL("sigemptyset() failed");

#ifdef SIGINT
  if (sigaction(SIGINT, &sa, NULL) < 0)
    LOG_FATAL("sigaction(%d) failed", SIGINT);
#endif
#ifdef SIGTERM
  if (sigaction(SIGTERM, &sa, NULL) < 0)
    LOG_FATAL("sigaction(%d) failed", SIGTERM);
#endif
#ifdef SIGQUIT
  if (sigaction(SIGQUIT, &sa, NULL) < 0)
    LOG_FATAL("sigaction(%d) failed", SIGQUIT);
#endif
#ifdef SIGHUP
  if (sigaction(SIGHUP, &sa, NULL) < 0)
    LOG_FATAL("sigaction(%d) failed", SIGHUP);
#endif

  if (ignore_sigpipe)
    sa.sa_handler = SIG_IGN;

  if (sigaction(SIGPIPE, &sa, NULL) < 0)
    LOG_FATAL("sigaction(%d) failed", SIGPIPE);
}

/* ================================================== */

char *
UTI_PathToDir(const char *path)
{
  char *dir, *slash;

  slash = strrchr(path, '/');

  if (!slash)
    return Strdup(".");

  if (slash == path)
    return Strdup("/");

  dir = Malloc(slash - path + 1);
  snprintf(dir, slash - path + 1, "%s", path);

  return dir;
}

/* ================================================== */

static int
create_dir(char *p, mode_t mode, uid_t uid, gid_t gid)
{
  int status;
  struct stat buf;

  /* See if directory exists */
  status = stat(p, &buf);

  if (status < 0) {
    if (errno != ENOENT) {
      LOG(LOGS_ERR, "Could not access %s : %s", p, strerror(errno));
      return 0;
    }
  } else {
    if (S_ISDIR(buf.st_mode))
      return 1;
    LOG(LOGS_ERR, "%s is not directory", p);
    return 0;
  }

  /* Create the directory */
  if (mkdir(p, mode) < 0) {
    LOG(LOGS_ERR, "Could not create directory %s : %s", p, strerror(errno));
    return 0;
  }

  /* Set its owner */
  if (chown(p, uid, gid) < 0) {
    LOG(LOGS_ERR, "Could not change ownership of %s : %s", p, strerror(errno));
    /* Don't leave it there with incorrect ownership */
    rmdir(p);
    return 0;
  }

  return 1;
}

/* ================================================== */
/* Return 0 if the directory couldn't be created, 1 if it could (or
   already existed) */
int
UTI_CreateDirAndParents(const char *path, mode_t mode, uid_t uid, gid_t gid)
{
  char *p;
  int i, j, k, last;

  /* Don't try to create current directory */
  if (!strcmp(path, "."))
    return 1;

  p = (char *)Malloc(1 + strlen(path));

  i = k = 0;
  while (1) {
    p[i++] = path[k++];

    if (path[k] == '/' || !path[k]) {
      /* Check whether its end of string, a trailing / or group of / */
      last = 1;
      j = k;
      while (path[j]) {
        if (path[j] != '/') {
          /* Pick up a / into p[] thru the assignment at the top of the loop */
          k = j - 1;
          last = 0;
          break;
        }
        j++;
      }

      p[i] = 0;

      if (!create_dir(p, last ? mode : 0755, last ? uid : 0, last ? gid : 0)) {
        Free(p);
        return 0;
      }

      if (last)
        break;
    }

    if (!path[k])
      break;
  }

  Free(p);
  return 1;
}

/* ================================================== */

int
UTI_CheckDirPermissions(const char *path, mode_t perm, uid_t uid, gid_t gid)
{
  struct stat buf;

  if (stat(path, &buf)) {
    LOG(LOGS_ERR, "Could not access %s : %s", path, strerror(errno));
    return 0;
  }

  if (!S_ISDIR(buf.st_mode)) {
    LOG(LOGS_ERR, "%s is not directory", path);
    return 0;
  }

  if ((buf.st_mode & 0777) & ~perm) {
    LOG(LOGS_ERR, "Wrong permissions on %s", path);
    return 0;
  }

  if (buf.st_uid != uid) {
    LOG(LOGS_ERR, "Wrong owner of %s (%s != %u)", path, "UID", uid);
    return 0;
  }

  if (buf.st_gid != gid) {
    LOG(LOGS_ERR, "Wrong owner of %s (%s != %u)", path, "GID", gid);
    return 0;
  }

  return 1;
}

/* ================================================== */

static int
join_path(const char *basedir, const char *name, const char *suffix,
          char *buffer, size_t length, LOG_Severity severity)
{
  const char *sep;

  if (!basedir) {
    basedir = "";
    sep = "";
  } else {
    sep = "/";
  }

  if (!suffix)
    suffix = "";

  if (snprintf(buffer, length, "%s%s%s%s", basedir, sep, name, suffix) >= length) {
    LOG(severity, "File path %s%s%s%s too long", basedir, sep, name, suffix);
    return 0;
  }

  return 1;
}

/* ================================================== */

FILE *
UTI_OpenFile(const char *basedir, const char *name, const char *suffix,
             char mode, mode_t perm)
{
  const char *file_mode;
  char path[PATH_MAX];
  LOG_Severity severity;
  int fd, flags;
  FILE *file;

  severity = mode >= 'A' && mode <= 'Z' ? LOGS_FATAL : LOGS_ERR;

  if (!join_path(basedir, name, suffix, path, sizeof (path), severity))
    return NULL;

  switch (mode) {
    case 'r':
    case 'R':
      flags = O_RDONLY;
      file_mode = "r";
      if (severity != LOGS_FATAL)
        severity = LOGS_DEBUG;
      break;
    case 'w':
    case 'W':
      flags = O_WRONLY | O_CREAT | O_EXCL;
      file_mode = "w";
      break;
    case 'a':
    case 'A':
      flags = O_WRONLY | O_CREAT | O_APPEND;
      file_mode = "a";
      break;
    default:
      assert(0);
      return NULL;
  }

try_again:
  fd = open(path, flags, perm);
  if (fd < 0) {
    if (errno == EEXIST) {
      if (unlink(path) < 0) {
        LOG(severity, "Could not remove %s : %s", path, strerror(errno));
        return NULL;
      }
      DEBUG_LOG("Removed %s", path);
      goto try_again;
    }
    LOG(severity, "Could not open %s : %s", path, strerror(errno));
    return NULL;
  }

  UTI_FdSetCloexec(fd);

  file = fdopen(fd, file_mode);
  if (!file) {
    LOG(severity, "Could not open %s : %s", path, strerror(errno));
    close(fd);
    return NULL;
  }

  DEBUG_LOG("Opened %s fd=%d mode=%c", path, fd, mode);

  return file;
}

/* ================================================== */

int
UTI_RenameTempFile(const char *basedir, const char *name,
                   const char *old_suffix, const char *new_suffix)
{
  char old_path[PATH_MAX], new_path[PATH_MAX];

  if (!join_path(basedir, name, old_suffix, old_path, sizeof (old_path), LOGS_ERR))
    return 0;

  if (!join_path(basedir, name, new_suffix, new_path, sizeof (new_path), LOGS_ERR))
    goto error;

  if (rename(old_path, new_path) < 0) {
    LOG(LOGS_ERR, "Could not replace %s with %s : %s", new_path, old_path, strerror(errno));
    goto error;
  }

  DEBUG_LOG("Renamed %s to %s", old_path, new_path);

  return 1;

error:
  if (unlink(old_path) < 0)
    LOG(LOGS_ERR, "Could not remove %s : %s", old_path, strerror(errno));

  return 0;
}

/* ================================================== */

int
UTI_RemoveFile(const char *basedir, const char *name, const char *suffix)
{
  char path[PATH_MAX];
  struct stat buf;

  if (!join_path(basedir, name, suffix, path, sizeof (path), LOGS_ERR))
    return 0;

  /* Avoid logging an error message if the file is not accessible */
  if (stat(path, &buf) < 0) {
    DEBUG_LOG("Could not remove %s : %s", path, strerror(errno));
    return 0;
  }

  if (unlink(path) < 0) {
    LOG(LOGS_ERR, "Could not remove %s : %s", path, strerror(errno));
    return 0;
  }

  DEBUG_LOG("Removed %s", path);

  return 1;
}

/* ================================================== */

void
UTI_DropRoot(uid_t uid, gid_t gid)
{
  /* Drop supplementary groups */
  if (setgroups(0, NULL))
    LOG_FATAL("setgroups() failed : %s", strerror(errno));

  /* Set effective, saved and real group ID */
  if (setgid(gid))
    LOG_FATAL("setgid(%u) failed : %s", gid, strerror(errno));

  /* Set effective, saved and real user ID */
  if (setuid(uid))
    LOG_FATAL("setuid(%u) failed : %s", uid, strerror(errno));

  DEBUG_LOG("Dropped root privileges: UID %u GID %u", uid, gid);
}

/* ================================================== */

#define DEV_URANDOM "/dev/urandom"

void
UTI_GetRandomBytesUrandom(void *buf, unsigned int len)
{
  static FILE *f = NULL;

  if (!f)
    f = UTI_OpenFile(NULL, DEV_URANDOM, NULL, 'R', 0);
  if (fread(buf, 1, len, f) != len)
    LOG_FATAL("Can't read from %s", DEV_URANDOM);
}

/* ================================================== */

#ifdef HAVE_GETRANDOM
static void
get_random_bytes_getrandom(char *buf, unsigned int len)
{
  static char rand_buf[256];
  static unsigned int available = 0, disabled = 0;
  unsigned int i;

  for (i = 0; i < len; i++) {
    if (!available) {
      if (disabled)
        break;

      if (getrandom(rand_buf, sizeof (rand_buf), GRND_NONBLOCK) != sizeof (rand_buf)) {
        disabled = 1;
        break;
      }

      available = sizeof (rand_buf);
    }

    buf[i] = rand_buf[--available];
  }

  if (i < len)
    UTI_GetRandomBytesUrandom(buf, len);
}
#endif

/* ================================================== */

void
UTI_GetRandomBytes(void *buf, unsigned int len)
{
#ifdef HAVE_ARC4RANDOM
  arc4random_buf(buf, len);
#elif defined(HAVE_GETRANDOM)
  get_random_bytes_getrandom(buf, len);
#else
  UTI_GetRandomBytesUrandom(buf, len);
#endif
}

/* ================================================== */

int
UTI_BytesToHex(const void *buf, unsigned int buf_len, char *hex, unsigned int hex_len)
{
  unsigned int i, l;

  for (i = l = 0; i < buf_len; i++, l += 2) {
    if (l + 2 >= hex_len ||
        snprintf(hex + l, hex_len - l, "%02hhX", ((const char *)buf)[i]) != 2)
      return 0;
  }

  return 1;
}

/* ================================================== */

unsigned int
UTI_HexToBytes(const char *hex, void *buf, unsigned int len)
{
  char *p, byte[3];
  unsigned int i;

  for (i = 0; i < len && *hex != '\0'; i++) {
    byte[0] = *hex++;
    if (*hex == '\0')
      return 0;
    byte[1] = *hex++;
    byte[2] = '\0';
    ((char *)buf)[i] = strtol(byte, &p, 16);

    if (p != byte + 2)
      return 0;
  }

  return *hex == '\0' ? i : 0;
}

/* ================================================== */

int
UTI_SplitString(char *string, char **words, int max_saved_words)
{
  char *s = string;
  int i;

  for (i = 0; i < max_saved_words; i++)
    words[i] = NULL;

  for (i = 0; ; i++) {
    /* Zero white-space characters before the word */
    while (*s != '\0' && isspace((unsigned char)*s))
      *s++ = '\0';

    if (*s == '\0')
      break;

    if (i < max_saved_words)
      words[i] = s;

    /* Find the next word */
    while (*s != '\0' && !isspace((unsigned char)*s))
      s++;
  }

  return i;
}