posix/tst-mmap-offset.c

   1 /* BZ #18877, BZ #21270, and BZ #24699 mmap offset test.
   2
   3    Copyright (C) 2015-2024 Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <https://www.gnu.org/licenses/>.  */
  19
  20 #include <stdint.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <unistd.h>
  25 #include <errno.h>
  26 #include <sys/mman.h>
  27 #include <mmap_info.h>
  28
  29 #include <support/check.h>
  30
  31 static int fd;
  32 static long int page_shift;
  33 static char fname[] = "/tmp/tst-mmap-offset-XXXXXX";
  34
  35 static void
  36 do_prepare (int argc, char **argv)
  37 {
  38   fd = mkstemp64 (fname);
  39   if (fd < 0)
  40     FAIL_EXIT1 ("mkstemp failed");
  41
  42   if (unlink (fname))
  43     FAIL_EXIT1 ("unlink failed");
  44
  45   long sz = sysconf(_SC_PAGESIZE);
  46   if (sz == -1)
  47     sz = 4096L;
  48   page_shift = ffs (sz) - 1;
  49 }
  50
  51 #define PREPARE do_prepare
  52
  53
  54 /* Check if negative offsets are handled correctly by mmap.  */
  55 static int
  56 do_test_bz18877 (void)
  57 {
  58   const int prot = PROT_READ | PROT_WRITE;
  59   const int flags = MAP_SHARED;
  60   const unsigned long length = 0x10000;
  61   const unsigned long offset = 0xace00000;
  62   const unsigned long size = offset + length;
  63   void *addr;
  64
  65   if (ftruncate64 (fd, size))
  66     FAIL_RET ("ftruncate64 failed");
  67
  68   addr = mmap (NULL, length, prot, flags, fd, offset);
  69   if (MAP_FAILED == addr)
  70     FAIL_RET ("mmap failed");
  71
  72   /* This memcpy is likely to SIGBUS if mmap has messed up with offset.  */
  73   memcpy (addr, fname, sizeof (fname));
  74
  75   return 0;
  76 }
  77
  78 /* Check if invalid offset are handled correctly by mmap.  */
  79 static int
  80 do_test_large_offset (void)
  81 {
  82   /* For architectures with sizeof (off_t) < sizeof (off64_t) mmap is
  83      implemented with __SYS_mmap2 syscall and the offset is represented in
  84      multiples of page size.  For offset larger than
  85      '1 << (page_shift + 8 * sizeof (off_t))' (that is, 1<<44 on system with
  86      page size of 4096 bytes) the system call silently truncates the offset.
  87      For this case glibc mmap implementation returns EINVAL.  */
  88   const int prot = PROT_READ | PROT_WRITE;
  89   const int flags = MAP_SHARED;
  90   const int64_t offset = 1ULL << (page_shift + 8 * sizeof (uint32_t));
  91   const size_t length = 4096;
  92
  93   void *addr = mmap64 (NULL, length, prot, flags, fd, offset);
  94   if (mmap64_maximum_offset (page_shift) < UINT64_MAX)
  95     {
  96       if ((addr != MAP_FAILED) && (errno != EINVAL))
  97         FAIL_RET ("mmap succeed");
  98     }
  99   else
 100     {
 101       if (addr == MAP_FAILED)
 102         FAIL_RET ("mmap failed");
 103     }
 104
 105   return 0;
 106 }
 107
 108 int
 109 do_test (void)
 110 {
 111   int ret = 0;
 112
 113   ret += do_test_bz18877 ();
 114   ret += do_test_large_offset ();
 115
 116   return ret;
 117 }
 118
 119 #include <support/test-driver.c>