text: /* mmap - map files or devices into memory.  Linux version.
     Copyright (C) 1999-2019 Free Software Foundation, Inc.
     This file is part of the GNU C Library.
     Contributed by Jakub Jelinek <jakub@redhat.com>, 1999.
  
     The GNU C Library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Lesser General Public
     License as published by the Free Software Foundation; either
     version 2.1 of the License, or (at your option) any later version.
  
     The GNU C Library is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     Lesser General Public License for more details.
  
     You should have received a copy of the GNU Lesser General Public
     License along with the GNU C Library; if not, see
     <http://www.gnu.org/licenses/>.  */
  
  #include <errno.h>
  #include <mmap_internal.h>
  #include <sys/mman.h>
  #include <sysdep.h>
  #include <unistd.h>
  
  /* To avoid silent truncation of offset when using mmap2, do not accept
     offset larger than 1 << (page_shift + off_t bits).  For archictures with
     32 bits off_t and page size of 4096 it would be 1^44.  */
  #define MMAP_OFF_HIGH_MASK                                                     \
      ((-(MMAP2_PAGE_UNIT << 1) << (8 * sizeof(off_t) - 1)))
  
  #define MMAP_OFF_MASK (MMAP_OFF_HIGH_MASK | MMAP_OFF_LOW_MASK)
  
  /* An architecture may override this.  */
  #ifndef MMAP_PREPARE
  #define MMAP_PREPARE(addr, len, prot, flags, fd, offset)
  #endif
  
  void* __mmap64(void* addr, size_t len, int prot, int flags, int fd,
                 off64_t offset)
  {
      MMAP_CHECK_PAGE_UNIT();
  
      if (offset & MMAP_OFF_MASK)
          return (void*)INLINE_SYSCALL_ERROR_RETURN_VALUE(EINVAL);
  
      MMAP_PREPARE(addr, len, prot, flags, fd, offset);
  #ifdef __NR_mmap2
      return (void*)MMAP_CALL(mmap2, addr, len, prot, flags, fd,
                              (off_t)(offset / MMAP2_PAGE_UNIT));
  #else
      return (void*)MMAP_CALL(mmap, addr, len, prot, flags, fd, offset);
  #endif
  }
  weak_alias(__mmap64, mmap64) libc_hidden_def(__mmap64)
  
  #ifdef __OFF_T_MATCHES_OFF64_T
      weak_alias(__mmap64, mmap) weak_alias(__mmap64, __mmap)
          libc_hidden_def(__mmap)
  #endif
  