1// Copyright 2014 The Chromium Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style license that can be 3// found in the LICENSE file. 4 5#include <errno.h> 6#include <sys/mman.h> 7 8#include "base/logging.h" 9#include "components/nacl/loader/nonsfi/irt_interfaces.h" 10#include "components/nacl/loader/nonsfi/irt_util.h" 11#include "native_client/src/trusted/service_runtime/include/machine/_types.h" 12#include "native_client/src/trusted/service_runtime/include/sys/mman.h" 13 14namespace nacl { 15namespace nonsfi { 16namespace { 17 18int NaClProtToProt(int nacl_prot) { 19 int prot = 0; 20 if ((nacl_prot & NACL_ABI_PROT_MASK) == NACL_ABI_PROT_NONE) 21 return PROT_NONE; 22 23 if (nacl_prot & NACL_ABI_PROT_READ) 24 prot |= PROT_READ; 25 if (nacl_prot & NACL_ABI_PROT_WRITE) 26 prot |= PROT_WRITE; 27 if (nacl_prot & NACL_ABI_PROT_EXEC) 28 prot |= PROT_EXEC; 29 return prot; 30} 31 32int NaClFlagsToFlags(int nacl_flags) { 33 int flags = 0; 34 35 if (nacl_flags & NACL_ABI_MAP_SHARED) 36 flags |= MAP_SHARED; 37 if (nacl_flags & NACL_ABI_MAP_PRIVATE) 38 flags |= MAP_PRIVATE; 39 if (nacl_flags & NACL_ABI_MAP_FIXED) 40 flags |= MAP_FIXED; 41 42 // Note: NACL_ABI_MAP_ANON is an alias of NACL_ABI_MAP_ANONYMOUS. 43 if (nacl_flags & NACL_ABI_MAP_ANONYMOUS) 44 flags |= MAP_ANONYMOUS; 45 return flags; 46} 47 48int IrtMMap(void** addr, size_t len, int prot, int flags, 49 int fd, nacl_abi_off_t off) { 50 const int host_prot = NaClProtToProt(prot); 51 // On Chrome OS, mmap can fail if PROT_EXEC is set in |host_prot|, 52 // but mprotect will allow changing the permissions later. 53 // This is because Chrome OS mounts writable filesystems with "noexec". 54 void* result = mmap( 55 *addr, len, host_prot & ~PROT_EXEC, NaClFlagsToFlags(flags), fd, off); 56 if (result == MAP_FAILED) 57 return errno; 58 if (host_prot & PROT_EXEC) { 59 if (mprotect(result, len, host_prot) != 0) { 60 // This aborts here because it cannot easily undo the mmap() call. 61 PLOG(FATAL) << "IrtMMap: mprotect to turn on PROT_EXEC failed."; 62 } 63 } 64 65 *addr = result; 66 return 0; 67} 68 69int IrtMUnmap(void* addr, size_t len) { 70 return CheckError(munmap(addr, len)); 71} 72 73int IrtMProtect(void* addr, size_t len, int prot) { 74 return CheckError(mprotect(addr, len, NaClProtToProt(prot))); 75} 76 77} // namespace 78 79// For mmap, the argument types should be nacl_abi_off_t rather than off_t. 80// However, the definition of nacl_irt_memory uses the host type off_t, so here 81// we need to cast it. 82const nacl_irt_memory kIrtMemory = { 83 reinterpret_cast<int(*)(void**, size_t, int, int, int, off_t)>(IrtMMap), 84 IrtMUnmap, 85 IrtMProtect, 86}; 87 88} // namespace nonsfi 89} // namespace nacl 90