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

   1 /* Test for reading directories with getdents64.
   2    Copyright (C) 2019-2024 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 <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 <sys/mman.h>
  31 #include <unistd.h>
  32
  33 /* Called by large_buffer_checks below.  */
  34 static void
  35 large_buffer_check (int fd, char *large_buffer, size_t large_buffer_size)
  36 {
  37   xlseek (fd, 0, SEEK_SET);
  38   ssize_t ret = getdents64 (fd, large_buffer, large_buffer_size);
  39   if (ret < 0)
  40     FAIL_EXIT1 ("getdents64 for buffer of %zu bytes failed: %m",
  41                 large_buffer_size);
  42   if (ret < offsetof (struct dirent64, d_name))
  43     FAIL_EXIT1 ("getdents64 for buffer of %zu returned small value %zd",
  44                 large_buffer_size, ret);
  45 }
  46
  47 /* Bug 24740: Make sure that the system call argument is adjusted
  48    properly for the int type.  A large value should stay a large
  49    value, and not wrap around to something small, causing the system
  50    call to fail with EINVAL.  */
  51 static void
  52 large_buffer_checks (int fd)
  53 {
  54   size_t large_buffer_size;
  55   if (!__builtin_add_overflow (UINT_MAX, 2, &large_buffer_size))
  56     {
  57       int flags = MAP_ANONYMOUS | MAP_PRIVATE;
  58 #ifdef MAP_NORESERVE
  59       flags |= MAP_NORESERVE;
  60 #endif
  61       void *large_buffer = mmap (NULL, large_buffer_size,
  62                                  PROT_READ | PROT_WRITE, flags, -1, 0);
  63       if (large_buffer == MAP_FAILED)
  64         printf ("warning: could not allocate %zu bytes of memory,"
  65                 " subtests skipped\n", large_buffer_size);
  66       else
  67         {
  68           large_buffer_check (fd, large_buffer, INT_MAX);
  69           large_buffer_check (fd, large_buffer, (size_t) INT_MAX + 1);
  70           large_buffer_check (fd, large_buffer, (size_t) INT_MAX + 2);
  71           large_buffer_check (fd, large_buffer, UINT_MAX);
  72           large_buffer_check (fd, large_buffer, (size_t) UINT_MAX + 1);
  73           large_buffer_check (fd, large_buffer, (size_t) UINT_MAX + 2);
  74           xmunmap (large_buffer, large_buffer_size);
  75         }
  76     }
  77 }
  78
  79 static void
  80 do_test_large_size (void)
  81 {
  82   int fd = xopen (".", O_RDONLY | O_DIRECTORY, 0);
  83   TEST_VERIFY (fd >= 0);
  84   large_buffer_checks (fd);
  85
  86   xclose (fd);
  87 }
  88
  89 static void
  90 do_test_by_size (size_t buffer_size)
  91 {
  92   /* The test compares the iteration order with readdir64.  */
  93   DIR *reference = opendir (".");
  94   TEST_VERIFY_EXIT (reference != NULL);
  95
  96   int fd = xopen (".", O_RDONLY | O_DIRECTORY, 0);
  97   TEST_VERIFY (fd >= 0);
  98
  99   /* Perform two passes, with a rewind operating between passes.  */
 100   for (int pass = 0; pass < 2; ++pass)
 101     {
 102       /* Check that we need to fill the buffer multiple times.  */
 103       int read_count = 0;
 104
 105       while (true)
 106         {
 107           /* Simple way to make sure that the memcpy below does not read
 108              non-existing data.  */
 109           struct
 110           {
 111             char buffer[buffer_size];
 112             struct dirent64 pad;
 113           } data;
 114
 115           ssize_t ret = getdents64 (fd, &data.buffer, sizeof (data.buffer));
 116           if (ret < 0)
 117             FAIL_EXIT1 ("getdents64: %m");
 118           if (ret == 0)
 119             break;
 120           ++read_count;
 121
 122           char *current = data.buffer;
 123           char *end = data.buffer + ret;
 124           while (current != end)
 125             {
 126               struct dirent64 entry;
 127               memcpy (&entry, current, sizeof (entry));
 128               /* Truncate overlong strings.  */
 129               entry.d_name[sizeof (entry.d_name) - 1] = '\0';
 130               TEST_VERIFY (strlen (entry.d_name) < sizeof (entry.d_name) - 1);
 131
 132               errno = 0;
 133               struct dirent64 *refentry = readdir64 (reference);
 134               if (refentry == NULL && errno == 0)
 135                 FAIL_EXIT1 ("readdir64 failed too early, at: %s",
 136                             entry.d_name);
 137               else if (refentry == NULL)
 138                 FAIL_EXIT1 ("readdir64: %m");
 139
 140               TEST_COMPARE_STRING (entry.d_name, refentry->d_name);
 141               TEST_COMPARE (entry.d_ino, refentry->d_ino);
 142               TEST_COMPARE (entry.d_off, refentry->d_off);
 143               TEST_COMPARE (entry.d_type, refentry->d_type);
 144
 145               /* Offset zero is reserved for the first entry.  */
 146               TEST_VERIFY (entry.d_off != 0);
 147
 148               TEST_VERIFY_EXIT (entry.d_reclen <= end - current);
 149               current += entry.d_reclen;
 150             }
 151         }
 152
 153       /* We expect to have reached the end of the stream.  */
 154       errno = 0;
 155       TEST_VERIFY (readdir64 (reference) == NULL);
 156       TEST_COMPARE (errno, 0);
 157
 158       /* direntries_read has been called more than once.  */
 159       TEST_VERIFY (read_count > 0);
 160
 161       /* Rewind both directory streams.  */
 162       xlseek (fd, 0, SEEK_SET);
 163       rewinddir (reference);
 164     }
 165
 166   xclose (fd);
 167   closedir (reference);
 168 }
 169
 170 static int
 171 do_test (void)
 172 {
 173   do_test_by_size (512);
 174   do_test_by_size (1024);
 175   do_test_by_size (4096);
 176
 177   do_test_large_size ();
 178
 179   return 0;
 180 }
 181
 182 #include <support/test-driver.c>