sysdeps/unix/sysv/linux/tst-getdents64.c

   1 /* Test for reading directories with getdents64.
   2    Copyright (C) 2019 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    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <dirent.h>
  20 #include <errno.h>
  21 #include <fcntl.h>
  22 #include <limits.h>
  23 #include <stdbool.h>
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <support/check.h>
  28 #include <support/support.h>
  29 #include <support/xunistd.h>
  30 #include <unistd.h>
  31
  32 /* Called by large_buffer_checks below.  */
  33 static void
  34 large_buffer_check (int fd, char *large_buffer, size_t large_buffer_size)
  35 {
  36   xlseek (fd, 0, SEEK_SET);
  37   ssize_t ret = getdents64 (fd, large_buffer, large_buffer_size);
  38   if (ret < 0)
  39     FAIL_EXIT1 ("getdents64 for buffer of %zu bytes failed: %m",
  40                 large_buffer_size);
  41   if (ret < offsetof (struct dirent64, d_name))
  42     FAIL_EXIT1 ("getdents64 for buffer of %zu returned small value %zd",
  43                 large_buffer_size, ret);
  44 }
  45
  46 /* Bug 24740: Make sure that the system call argument is adjusted
  47    properly for the int type.  A large value should stay a large
  48    value, and not wrap around to something small, causing the system
  49    call to fail with EINVAL.  */
  50 static void
  51 large_buffer_checks (int fd)
  52 {
  53   size_t large_buffer_size;
  54   if (!__builtin_add_overflow (UINT_MAX, 2, &large_buffer_size))
  55     {
  56       char *large_buffer = malloc (large_buffer_size);
  57       if (large_buffer == NULL)
  58         printf ("warning: could not allocate %zu bytes of memory,"
  59                 " subtests skipped\n", large_buffer_size);
  60       else
  61         {
  62           large_buffer_check (fd, large_buffer, INT_MAX);
  63           large_buffer_check (fd, large_buffer, (size_t) INT_MAX + 1);
  64           large_buffer_check (fd, large_buffer, (size_t) INT_MAX + 2);
  65           large_buffer_check (fd, large_buffer, UINT_MAX);
  66           large_buffer_check (fd, large_buffer, (size_t) UINT_MAX + 1);
  67           large_buffer_check (fd, large_buffer, (size_t) UINT_MAX + 2);
  68         }
  69       free (large_buffer);
  70     }
  71 }
  72
  73 static int
  74 do_test (void)
  75 {
  76   /* The test compares the iteration order with readdir64.  */
  77   DIR *reference = opendir (".");
  78   TEST_VERIFY_EXIT (reference != NULL);
  79
  80   int fd = xopen (".", O_RDONLY | O_DIRECTORY, 0);
  81   TEST_VERIFY (fd >= 0);
  82
  83   /* Perform two passes, with a rewind operating between passes.  */
  84   for (int pass = 0; pass < 2; ++pass)
  85     {
  86       /* Check that we need to fill the buffer multiple times.  */
  87       int read_count = 0;
  88
  89       while (true)
  90         {
  91           /* Simple way to make sure that the memcpy below does not read
  92              non-existing data.  */
  93           struct
  94           {
  95             char buffer[1024];
  96             struct dirent64 pad;
  97           } data;
  98
  99           ssize_t ret = getdents64 (fd, &data.buffer, sizeof (data.buffer));
 100           if (ret < 0)
 101             FAIL_EXIT1 ("getdents64: %m");
 102           if (ret == 0)
 103             break;
 104           ++read_count;
 105
 106           char *current = data.buffer;
 107           char *end = data.buffer + ret;
 108           while (current != end)
 109             {
 110               struct dirent64 entry;
 111               memcpy (&entry, current, sizeof (entry));
 112               /* Truncate overlong strings.  */
 113               entry.d_name[sizeof (entry.d_name) - 1] = '\0';
 114               TEST_VERIFY (strlen (entry.d_name) < sizeof (entry.d_name) - 1);
 115
 116               errno = 0;
 117               struct dirent64 *refentry = readdir64 (reference);
 118               if (refentry == NULL && errno == 0)
 119                 FAIL_EXIT1 ("readdir64 failed too early, at: %s",
 120                             entry.d_name);
 121               else if (refentry == NULL)
 122                 FAIL_EXIT1 ("readdir64: %m");
 123
 124               TEST_COMPARE_STRING (entry.d_name, refentry->d_name);
 125               TEST_COMPARE (entry.d_ino, refentry->d_ino);
 126               TEST_COMPARE (entry.d_off, refentry->d_off);
 127               TEST_COMPARE (entry.d_type, refentry->d_type);
 128
 129               /* Offset zero is reserved for the first entry.  */
 130               TEST_VERIFY (entry.d_off != 0);
 131
 132               TEST_VERIFY_EXIT (entry.d_reclen <= end - current);
 133               current += entry.d_reclen;
 134             }
 135         }
 136
 137       /* We expect to have reached the end of the stream.  */
 138       errno = 0;
 139       TEST_VERIFY (readdir64 (reference) == NULL);
 140       TEST_COMPARE (errno, 0);
 141
 142       /* direntries_read has been called more than once.  */
 143       TEST_VERIFY (read_count > 0);
 144
 145       /* Rewind both directory streams.  */
 146       xlseek (fd, 0, SEEK_SET);
 147       rewinddir (reference);
 148     }
 149
 150   large_buffer_checks (fd);
 151
 152   xclose (fd);
 153   closedir (reference);
 154   return 0;
 155 }
 156
 157 #include <support/test-driver.c>