posix/tst-preadwrite-common.c

   1 /* Common definitions for pread and pwrite.
   2    Copyright (C) 2016-2024 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 }