gold/mremap.c

   1 /* mremap.c -- version of mremap for gold.  */
   2
   3 /* Copyright (C) 2009-2022 Free Software Foundation, Inc.
   4    Written by Ian Lance Taylor <iant@google.com>.
   5
   6    This file is part of gold.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  21    MA 02110-1301, USA.  */
  22
  23 #include "config.h"
  24 #include "ansidecl.h"
  25
  26 #include <errno.h>
  27 #include <string.h>
  28 #include <sys/types.h>
  29
  30 #ifdef HAVE_SYS_MMAN_H
  31 #include <sys/mman.h>
  32 #endif
  33
  34 extern void *gold_mremap (void *, size_t, size_t, int);
  35
  36 #ifdef HAVE_MMAP
  37
  38 /* This file implements mremap for systems which don't have it.  The
  39    gold code requires support for mmap.  However, there are systems
  40    which have mmap but not mremap.  This is not a general replacement
  41    for mremap; it only supports the features which are required for
  42    gold.  In particular, we assume that the MREMAP_MAYMOVE flag is
  43    set.  */
  44
  45 /* Some BSD systems still use MAP_ANON instead of MAP_ANONYMOUS.  */
  46
  47 #ifndef MAP_ANONYMOUS
  48 # define MAP_ANONYMOUS MAP_ANON
  49 #endif
  50
  51 void *
  52 gold_mremap (void *old_address, size_t old_size, size_t new_size,
  53              int flags ATTRIBUTE_UNUSED)
  54 {
  55   void *ret;
  56
  57   ret = mmap (0, new_size, PROT_READ | PROT_WRITE,
  58               MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
  59   if (ret == MAP_FAILED)
  60     return ret;
  61   memcpy (ret, old_address,
  62           old_size < new_size ? old_size : new_size);
  63   (void) munmap (old_address, old_size);
  64   return ret;
  65 }
  66
  67 #else /* !defined(HAVE_MMAP) */
  68
  69 #ifndef MAP_FAILED
  70 #define MAP_FAILED ((void *) -1)
  71 #endif
  72
  73 #ifndef ENOSYS
  74 #define ENOSYS EINVAL
  75 #endif
  76
  77 void *
  78 gold_mremap (void *old_address ATTRIBUTE_UNUSED,
  79              size_t old_size ATTRIBUTE_UNUSED,
  80              size_t new_size ATTRIBUTE_UNUSED,
  81              int flags ATTRIBUTE_UNUSED)
  82 {
  83   errno = ENOSYS;
  84   return MAP_FAILED;
  85 }
  86
  87 #endif /* !defined(HAVE_MMAP) */