Home | History | Annotate | Download | only in android 
      1 /*
      2  * Copyright (C) 2017 The Android Open Source Project
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  *  * Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  *  * Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in
     12  *    the documentation and/or other materials provided with the
     13  *    distribution.
     14  *
     15  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     16  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     17  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
     18  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
     19  * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
     20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     21  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
     22  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     23  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     24  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
     25  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  */
     28 
     29 #pragma once
     30 
     31 #include <sys/cdefs.h>
     32 
     33 #if __ANDROID_API__ < __ANDROID_API_L__
     34 
     35 #include <errno.h>
     36 #include <sys/mman.h>
     37 #include <unistd.h>
     38 
     39 __BEGIN_DECLS
     40 
     41 /*
     42  * While this was never an inline, this function alone has caused most of the
     43  * bug reports related to _FILE_OFFSET_BITS=64. Providing an inline for it
     44  * should allow a lot more code to build with _FILE_OFFSET_BITS=64 when
     45  * targeting pre-L.
     46  */
     47 static __inline void* mmap64(void* __addr, size_t __size, int __prot, int __flags, int __fd,
     48                              off64_t __offset) __RENAME(mmap64);
     49 static __inline void* mmap64(void* __addr, size_t __size, int __prot, int __flags, int __fd,
     50                              off64_t __offset) {
     51   const int __mmap2_shift = 12; // 2**12 == 4096
     52   if (__offset < 0 || (__offset & ((1UL << __mmap2_shift) - 1)) != 0) {
     53     errno = EINVAL;
     54     return MAP_FAILED;
     55   }
     56 
     57   // prevent allocations large enough for `end - start` to overflow
     58   size_t __rounded = __BIONIC_ALIGN(__size, PAGE_SIZE);
     59   if (__rounded < __size || __rounded > PTRDIFF_MAX) {
     60     errno = ENOMEM;
     61     return MAP_FAILED;
     62   }
     63 
     64   extern void* __mmap2(void* __addr, size_t __size, int __prot, int __flags, int __fd,
     65                        size_t __offset);
     66   return __mmap2(__addr, __size, __prot, __flags, __fd, __offset >> __mmap2_shift);
     67 }
     68 
     69 __END_DECLS
     70 
     71 #endif  /* __ANDROID_API__ < __ANDROID_API_L__ */
     72