text: /* crypto/rand/rand_unix.c */
  /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
   * All rights reserved.
   *
   * This package is an SSL implementation written
   * by Eric Young (eay@cryptsoft.com).
   * The implementation was written so as to conform with Netscapes SSL.
   *
   * This library is free for commercial and non-commercial use as long as
   * the following conditions are aheared to.  The following conditions
   * apply to all code found in this distribution, be it the RC4, RSA,
   * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
   * included with this distribution is covered by the same copyright terms
   * except that the holder is Tim Hudson (tjh@cryptsoft.com).
   *
   * Copyright remains Eric Young's, and as such any Copyright notices in
   * the code are not to be removed.
   * If this package is used in a product, Eric Young should be given attribution
   * as the author of the parts of the library used.
   * This can be in the form of a textual message at program startup or
   * in documentation (online or textual) provided with the package.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. All advertising materials mentioning features or use of this software
   *    must display the following acknowledgement:
   *    "This product includes cryptographic software written by
   *     Eric Young (eay@cryptsoft.com)"
   *    The word 'cryptographic' can be left out if the rouines from the library
   *    being used are not cryptographic related :-).
   * 4. If you include any Windows specific code (or a derivative thereof) from
   *    the apps directory (application code) you must include an acknowledgement:
   *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
   *
   * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   * The licence and distribution terms for any publically available version or
   * derivative of this code cannot be changed.  i.e. this code cannot simply be
   * copied and put under another distribution licence
   * [including the GNU Public Licence.]
   */
  /* ====================================================================
   * Copyright (c) 1998-2006 The OpenSSL Project.  All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   *
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   *
   * 3. All advertising materials mentioning features or use of this
   *    software must display the following acknowledgment:
   *    "This product includes software developed by the OpenSSL Project
   *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
   *
   * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
   *    endorse or promote products derived from this software without
   *    prior written permission. For written permission, please contact
   *    openssl-core@openssl.org.
   *
   * 5. Products derived from this software may not be called "OpenSSL"
   *    nor may "OpenSSL" appear in their names without prior written
   *    permission of the OpenSSL Project.
   *
   * 6. Redistributions of any form whatsoever must retain the following
   *    acknowledgment:
   *    "This product includes software developed by the OpenSSL Project
   *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
   *
   * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
   * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
   * OF THE POSSIBILITY OF SUCH DAMAGE.
   * ====================================================================
   *
   * This product includes cryptographic software written by Eric Young
   * (eay@cryptsoft.com).  This product includes software written by Tim
   * Hudson (tjh@cryptsoft.com).
   *
   */
  #include <stdio.h>
  
  #define USE_SOCKETS
  #include "e_os.h"
  #include "cryptlib.h"
  #include <openssl/rand.h>
  #include "rand_lcl.h"
  
  #if !(defined(OPENSSL_SYS_WINDOWS) || defined(OPENSSL_SYS_WIN32) || defined(OPENSSL_SYS_VMS) || defined(OPENSSL_SYS_OS2) || defined(OPENSSL_SYS_VXWORKS) || defined(OPENSSL_SYS_NETWARE))
  
  # include <sys/types.h>
  # include <sys/time.h>
  # include <sys/times.h>
  # include <sys/stat.h>
  # include <fcntl.h>
  # include <unistd.h>
  # include <time.h>
  # if defined(OPENSSL_SYS_LINUX) || defined(__NetBSD__) /* should actually
                                   * be available virtually everywhere */
  #  include <poll.h>
  # endif
  # include <limits.h>
  # ifndef FD_SETSIZE
  #  define FD_SETSIZE (8*sizeof(fd_set))
  # endif
  
  # if defined(OPENSSL_SYS_VOS)
  
  /*
   * The following algorithm repeatedly samples the real-time clock (RTC) to
   * generate a sequence of unpredictable data.  The algorithm relies upon the
   * uneven execution speed of the code (due to factors such as cache misses,
   * interrupts, bus activity, and scheduling) and upon the rather large
   * relative difference between the speed of the clock and the rate at which
   * it can be read.
   *
   * If this code is ported to an environment where execution speed is more
   * constant or where the RTC ticks at a much slower rate, or the clock can be
   * read with fewer instructions, it is likely that the results would be far
   * more predictable.
   *
   * As a precaution, we generate 4 times the minimum required amount of seed
   * data.
   */
  
  int RAND_poll(void)
  {
      short int code;
      gid_t curr_gid;
      pid_t curr_pid;
      uid_t curr_uid;
      int i, k;
      struct timespec ts;
      unsigned char v;
  
  #  ifdef OPENSSL_SYS_VOS_HPPA
      long duration;
      extern void s$sleep(long *_duration, short int *_code);
  #  else
  #   ifdef OPENSSL_SYS_VOS_IA32
      long long duration;
      extern void s$sleep2(long long *_duration, short int *_code);
  #   else
  #    error "Unsupported Platform."
  #   endif                       /* OPENSSL_SYS_VOS_IA32 */
  #  endif                        /* OPENSSL_SYS_VOS_HPPA */
  
      /*
       * Seed with the gid, pid, and uid, to ensure *some* variation between
       * different processes.
       */
  
      curr_gid = getgid();
      RAND_add(&curr_gid, sizeof curr_gid, 1);
      curr_gid = 0;
  
      curr_pid = getpid();
      RAND_add(&curr_pid, sizeof curr_pid, 1);
      curr_pid = 0;
  
      curr_uid = getuid();
      RAND_add(&curr_uid, sizeof curr_uid, 1);
      curr_uid = 0;
  
      for (i = 0; i < (ENTROPY_NEEDED * 4); i++) {
          /*
           * burn some cpu; hope for interrupts, cache collisions, bus
           * interference, etc.
           */
          for (k = 0; k < 99; k++)
              ts.tv_nsec = random();
  
  #  ifdef OPENSSL_SYS_VOS_HPPA
          /* sleep for 1/1024 of a second (976 us).  */
          duration = 1;
          s$sleep(&duration, &code);
  #  else
  #   ifdef OPENSSL_SYS_VOS_IA32
          /* sleep for 1/65536 of a second (15 us).  */
          duration = 1;
          s$sleep2(&duration, &code);
  #   endif                       /* OPENSSL_SYS_VOS_IA32 */
  #  endif                        /* OPENSSL_SYS_VOS_HPPA */
  
          /* get wall clock time.  */
          clock_gettime(CLOCK_REALTIME, &ts);
  
          /* take 8 bits */
          v = (unsigned char)(ts.tv_nsec % 256);
          RAND_add(&v, sizeof v, 1);
          v = 0;
      }
      return 1;
  }
  # elif defined __OpenBSD__
  int RAND_poll(void)
  {
      u_int32_t rnd = 0, i;
      unsigned char buf[ENTROPY_NEEDED];
  
      for (i = 0; i < sizeof(buf); i++) {
          if (i % 4 == 0)
              rnd = arc4random();
          buf[i] = rnd;
          rnd >>= 8;
      }
      RAND_add(buf, sizeof(buf), ENTROPY_NEEDED);
      memset(buf, 0, sizeof(buf));
  
      return 1;
  }
  # else                          /* !defined(__OpenBSD__) */
  int RAND_poll(void)
  {
      unsigned long l;
      pid_t curr_pid = getpid();
  #  if defined(DEVRANDOM) || defined(DEVRANDOM_EGD)
      unsigned char tmpbuf[ENTROPY_NEEDED];
      int n = 0;
  #  endif
  #  ifdef DEVRANDOM
      static const char *randomfiles[] = { DEVRANDOM };
      struct stat randomstats[sizeof(randomfiles) / sizeof(randomfiles[0])];
      int fd;
      unsigned int i;
  #  endif
  #  ifdef DEVRANDOM_EGD
      static const char *egdsockets[] = { DEVRANDOM_EGD, NULL };
      const char **egdsocket = NULL;
  #  endif
  
  #  ifdef DEVRANDOM
      memset(randomstats, 0, sizeof(randomstats));
      /*
       * Use a random entropy pool device. Linux, FreeBSD and OpenBSD have
       * this. Use /dev/urandom if you can as /dev/random may block if it runs
       * out of random entries.
       */
  
      for (i = 0; (i < sizeof(randomfiles) / sizeof(randomfiles[0])) &&
           (n < ENTROPY_NEEDED); i++) {
          if ((fd = open(randomfiles[i], O_RDONLY
  #   ifdef O_NONBLOCK
                         | O_NONBLOCK
  #   endif
  #   ifdef O_BINARY
                         | O_BINARY
  #   endif
  #   ifdef O_NOCTTY              /* If it happens to be a TTY (god forbid), do
                                   * not make it our controlling tty */
                         | O_NOCTTY
  #   endif
               )) >= 0) {
              int usec = 10 * 1000; /* spend 10ms on each file */
              int r;
              unsigned int j;
              struct stat *st = &randomstats[i];
  
              /*
               * Avoid using same input... Used to be O_NOFOLLOW above, but
               * it's not universally appropriate...
               */
              if (fstat(fd, st) != 0) {
                  close(fd);
                  continue;
              }
              for (j = 0; j < i; j++) {
                  if (randomstats[j].st_ino == st->st_ino &&
                      randomstats[j].st_dev == st->st_dev)
                      break;
              }
              if (j < i) {
                  close(fd);
                  continue;
              }
  
              do {
                  int try_read = 0;
  
  #   if defined(OPENSSL_SYS_BEOS_R5)
                  /*
                   * select() is broken in BeOS R5, so we simply try to read
                   * something and snooze if we couldn't
                   */
                  try_read = 1;
  
  #   elif defined(OPENSSL_SYS_LINUX) || defined(__NetBSD__)
                  /* use poll() */
                  struct pollfd pset;
  
                  pset.fd = fd;
                  pset.events = POLLIN;
                  pset.revents = 0;
  
                  if (poll(&pset, 1, usec / 1000) < 0)
                      usec = 0;
                  else
                      try_read = (pset.revents & POLLIN) != 0;
  
  #   else
                  /* use select() */
                  fd_set fset;
                  struct timeval t;
  
                  t.tv_sec = 0;
                  t.tv_usec = usec;
  
                  if (FD_SETSIZE > 0 && (unsigned)fd >= FD_SETSIZE) {
                      /*
                       * can't use select, so just try to read once anyway
                       */
                      try_read = 1;
                  } else {
                      FD_ZERO(&fset);
                      FD_SET(fd, &fset);
  
                      if (select(fd + 1, &fset, NULL, NULL, &t) >= 0) {
                          usec = t.tv_usec;
                          if (FD_ISSET(fd, &fset))
                              try_read = 1;
                      } else
                          usec = 0;
                  }
  #   endif
  
                  if (try_read) {
                      r = read(fd, (unsigned char *)tmpbuf + n,
                               ENTROPY_NEEDED - n);
                      if (r > 0)
                          n += r;
  #   if defined(OPENSSL_SYS_BEOS_R5)
                      if (r == 0)
                          snooze(t.tv_usec);
  #   endif
                  } else
                      r = -1;
  
                  /*
                   * Some Unixen will update t in select(), some won't.  For
                   * those who won't, or if we didn't use select() in the first
                   * place, give up here, otherwise, we will do this once again
                   * for the remaining time.
                   */
                  if (usec == 10 * 1000)
                      usec = 0;
              }
              while ((r > 0 ||
                      (errno == EINTR || errno == EAGAIN)) && usec != 0
                     && n < ENTROPY_NEEDED);
  
              close(fd);
          }
      }
  #  endif                        /* defined(DEVRANDOM) */
  
  #  ifdef DEVRANDOM_EGD
      /*
       * Use an EGD socket to read entropy from an EGD or PRNGD entropy
       * collecting daemon.
       */
  
      for (egdsocket = egdsockets; *egdsocket && n < ENTROPY_NEEDED;
           egdsocket++) {
          int r;
  
          r = RAND_query_egd_bytes(*egdsocket, (unsigned char *)tmpbuf + n,
                                   ENTROPY_NEEDED - n);
          if (r > 0)
              n += r;
      }
  #  endif                        /* defined(DEVRANDOM_EGD) */
  
  #  if defined(DEVRANDOM) || defined(DEVRANDOM_EGD)
      if (n > 0) {
          RAND_add(tmpbuf, sizeof tmpbuf, (double)n);
          OPENSSL_cleanse(tmpbuf, n);
      }
  #  endif
  
      /* put in some default random data, we need more than just this */
      l = curr_pid;
      RAND_add(&l, sizeof(l), 0.0);
      l = getuid();
      RAND_add(&l, sizeof(l), 0.0);
  
      l = time(NULL);
      RAND_add(&l, sizeof(l), 0.0);
  
  #  if defined(OPENSSL_SYS_BEOS)
      {
          system_info sysInfo;
          get_system_info(&sysInfo);
          RAND_add(&sysInfo, sizeof(sysInfo), 0);
      }
  #  endif
  
  #  if defined(DEVRANDOM) || defined(DEVRANDOM_EGD)
      return 1;
  #  else
      return 0;
  #  endif
  }
  
  # endif                         /* defined(__OpenBSD__) */
  #endif                          /* !(defined(OPENSSL_SYS_WINDOWS) ||
                                   * defined(OPENSSL_SYS_WIN32) ||
                                   * defined(OPENSSL_SYS_VMS) ||
                                   * defined(OPENSSL_SYS_OS2) ||
                                   * defined(OPENSSL_SYS_VXWORKS) ||
                                   * defined(OPENSSL_SYS_NETWARE)) */
  
  #if defined(OPENSSL_SYS_VXWORKS)
  int RAND_poll(void)
  {
      return 0;
  }
  #endif
  