kc3-lang/gnulib/tests/test-getrandom.c

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• Hash : 32a72f45
  Author :
  Date : 2023-01-01T01:14:21
  

  maint: run 'make update-copyright'
  

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• tests/test-getrandom.c

• /* Test of getting random bytes.
     Copyright (C) 2020-2023 Free Software Foundation, Inc.
  
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
     the Free Software Foundation, either version 3 of the License, or
     (at your option) any later version.
  
     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, see <https://www.gnu.org/licenses/>.  */
  
  /* Written by Bruno Haible.  */
  
  #include <config.h>
  
  #include <sys/random.h>
  
  #include "signature.h"
  SIGNATURE_CHECK (getrandom, ssize_t, (void *, size_t, unsigned int));
  
  #include <errno.h>
  #include <string.h>
  
  #include "macros.h"
  
  int
  main (void)
  {
    char buf1[8];
    char buf2[8];
    char large_buf[100000];
    ssize_t ret;
  
    /* Check that different calls produce different results (with a high
       probability).  */
    ret = getrandom (buf1, sizeof (buf1), 0);
    if (ret < 0)
      ASSERT (errno == ENOSYS);
    else
      {
        ret = getrandom (buf2, sizeof (buf2), 0);
        if (ret < 0)
          ASSERT (errno == ENOSYS);
        else
          {
            /* It is very unlikely that two calls to getrandom produce the
               same results.  */
            ASSERT (memcmp (buf1, buf2, sizeof (buf1)) != 0);
          }
      }
  
    /* Likewise with the "truly random" number generator.  */
    ret = getrandom (buf1, sizeof (buf1), GRND_RANDOM);
    if (ret < 0)
      ASSERT (errno == ENOSYS);
    else
      {
        ret = getrandom (buf2, sizeof (buf2), GRND_RANDOM);
        if (ret < 0)
          ASSERT (errno == ENOSYS);
        else
          {
            /* It is very unlikely that two calls to getrandom produce the
               same results.  */
            ASSERT (memcmp (buf1, buf2, sizeof (buf1)) != 0);
          }
      }
  
    /* Check that GRND_NONBLOCK works.  */
    ret = getrandom (large_buf, sizeof (large_buf), GRND_RANDOM | GRND_NONBLOCK);
    ASSERT (ret <= (ssize_t) sizeof (large_buf));
    /* It is very unlikely that so many truly random bytes were ready.  */
    if (ret < 0)
      ASSERT (errno == ENOSYS || errno == EAGAIN
              || errno == EINVAL /* Solaris */);
    else
      ASSERT (ret > 0);
  
    if (getrandom (buf1, 1, 0) < 1)
      if (getrandom (buf1, 1, GRND_RANDOM) < 1)
        {
          fputs ("Skipping test: getrandom is ineffective\n", stderr);
          return 77;
        }
  
    return 0;
  }
  

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