posix/tst-mmap-offset.c

   1 /* BZ #18877 and #21270 mmap offset test.
   2
   3    Copyright (C) 2015-2017 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    <http://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
  28 #include <support/check.h>
  29
  30 static int fd;
  31 static long int page_shift;
  32 static char fname[] = "tst-mmap-offset-XXXXXX";
  33
  34 static void
  35 do_prepare (int argc, char **argv)
  36 {
  37   fd = mkstemp64 (fname);
  38   if (fd < 0)
  39     FAIL_EXIT1 ("mkstemp failed");
  40
  41   if (unlink (fname))
  42     FAIL_EXIT1 ("unlink failed");
  43
  44   long sz = sysconf(_SC_PAGESIZE);
  45   if (sz == -1)
  46     sz = 4096L;
  47   page_shift = ffs (sz) - 1;
  48 }
  49
  50 #define PREPARE do_prepare
  51
  52
  53 /* Check if negative offsets are handled correctly by mmap.  */
  54 static int
  55 do_test_bz18877 (void)
  56 {
  57   const int prot = PROT_READ | PROT_WRITE;
  58   const int flags = MAP_SHARED;
  59   const unsigned long length = 0x10000;
  60   const unsigned long offset = 0xace00000;
  61   const unsigned long size = offset + length;
  62   void *addr;
  63
  64   if (ftruncate64 (fd, size))
  65     FAIL_RET ("ftruncate64 failed");
  66
  67   addr = mmap (NULL, length, prot, flags, fd, offset);
  68   if (MAP_FAILED == addr)
  69     FAIL_RET ("mmap failed");
  70
  71   /* This memcpy is likely to SIGBUS if mmap has messed up with offset.  */
  72   memcpy (addr, fname, sizeof (fname));
  73
  74   return 0;
  75 }
  76
  77 /* Check if invalid offset are handled correctly by mmap.  */
  78 static int
  79 do_test_bz21270 (void)
  80 {
  81   /* For architectures with sizeof (off_t) < sizeof (off64_t) mmap is
  82      implemented with __SYS_mmap2 syscall and the offset is represented in
  83      multiples of page size.  For offset larger than
  84      '1 << (page_shift + 8 * sizeof (off_t))' (that is, 1<<44 on system with
  85      page size of 4096 bytes) the system call silently truncates the offset.
  86      For this case glibc mmap implementation returns EINVAL.  */
  87   const int prot = PROT_READ | PROT_WRITE;
  88   const int flags = MAP_SHARED;
  89   const int64_t offset = 1ULL << (page_shift + 8 * sizeof (uint32_t));
  90   const size_t length = 4096;
  91
  92   void *addr = mmap64 (NULL, length, prot, flags, fd, offset);
  93   if (sizeof (off_t) < sizeof (off64_t))
  94     {
  95       if ((addr != MAP_FAILED) && (errno != EINVAL))
  96         FAIL_RET ("mmap succeed");
  97     }
  98   else
  99     {
 100       if (addr == MAP_FAILED)
 101         FAIL_RET ("mmap failed");
 102     }
 103
 104   return 0;
 105 }
 106
 107 int
 108 do_test (void)
 109 {
 110   int ret = 0;
 111
 112   ret += do_test_bz18877 ();
 113   ret += do_test_bz21270 ();
 114
 115   return ret;
 116 }
 117
 118 #include <support/test-driver.c>