1  /* Common definitions for pread and pwrite.
       2     Copyright (C) 2016-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; if not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #include <errno.h>
      20  #include <error.h>
      21  #include <string.h>
      22  #include <unistd.h>
      23  #include <sys/stat.h>
      24  
      25  static void do_prepare (void);
      26  #define PREPARE(argc, argv)	do_prepare ()
      27  static int do_test (void);
      28  #define TEST_FUNCTION		do_test ()
      29  
      30  /* This defines the `main' function and some more.  */
      31  #include <test-skeleton.c>
      32  
      33  /* These are for the temporary file we generate.  */
      34  static char *name;
      35  static int fd;
      36  
      37  static void
      38  do_prepare (void)
      39  {
      40    fd = create_temp_file ("tst-preadwrite.", &name);
      41    if (fd == -1)
      42      error (EXIT_FAILURE, errno, "cannot create temporary file");
      43  }
      44  
      45  
      46  static ssize_t
      47  do_test_with_offset (off_t offset)
      48  {
      49    char buf[1000];
      50    char res[1000];
      51    int i;
      52    ssize_t ret;
      53  
      54    memset (buf, '\0', sizeof (buf));
      55    memset (res, '\xff', sizeof (res));
      56  
      57    if (write (fd, buf, sizeof (buf)) != sizeof (buf))
      58      error (EXIT_FAILURE, errno, "during write");
      59  
      60    for (i = 100; i < 200; ++i)
      61      buf[i] = i;
      62    ret = pwrite (fd, buf + 100, 100, offset + 100);
      63    if (ret == -1)
      64      error (EXIT_FAILURE, errno, "during pwrite");
      65  
      66    for (i = 450; i < 600; ++i)
      67      buf[i] = i;
      68    ret = pwrite (fd, buf + 450, 150, offset + 450);
      69    if (ret == -1)
      70      error (EXIT_FAILURE, errno, "during pwrite");
      71  
      72    ret = pread (fd, res, sizeof (buf) - 50, offset + 50);
      73    if (ret == -1)
      74      error (EXIT_FAILURE, errno, "during pread");
      75  
      76    if (memcmp (buf + 50, res, ret) != 0)
      77      {
      78        printf ("error: read of pread != write of pwrite\n");
      79        return -1;
      80      }
      81  
      82    return ret;
      83  }