1 /* 2 * Copyright (C) 2018 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef ART_LIBARTBASE_BASE_MEMFD_H_ 18 #define ART_LIBARTBASE_BASE_MEMFD_H_ 19 20 #include <fcntl.h> 21 #include <unistd.h> 22 23 #if defined(__BIONIC__) 24 #include <linux/memfd.h> // To access memfd flags. 25 #else 26 27 // If memfd flags don't exist in the current toolchain, define them ourselves. 28 #ifndef F_ADD_SEALS 29 # define F_ADD_SEALS (1033) 30 #endif 31 32 #ifndef F_GET_SEALS 33 # define F_GET_SEALS (1034) 34 #endif 35 36 #ifndef F_SEAL_SEAL 37 # define F_SEAL_SEAL 0x0001 38 #endif 39 40 #ifndef F_SEAL_SHRINK 41 # define F_SEAL_SHRINK 0x0002 42 #endif 43 44 #ifndef F_SEAL_GROW 45 # define F_SEAL_GROW 0x0004 46 #endif 47 48 #ifndef F_SEAL_WRITE 49 # define F_SEAL_WRITE 0x0008 50 #endif 51 52 #ifndef F_SEAL_FUTURE_WRITE 53 # define F_SEAL_FUTURE_WRITE 0x0010 54 #endif 55 56 #ifndef MFD_ALLOW_SEALING 57 # define MFD_ALLOW_SEALING 0x0002U 58 #endif 59 60 #endif 61 62 namespace art { 63 64 // Call memfd(2) if available on platform and return result. This call also makes a kernel version 65 // check for safety on older kernels (b/116769556).. 66 int memfd_create(const char* name, unsigned int flags); 67 68 // Call memfd(2) if available on platform and return result. Try to give us an unlinked FD in some 69 // other way if memfd fails or isn't supported. 70 int memfd_create_compat(const char* name, unsigned int flags); 71 72 // Return whether the kernel supports sealing future writes of a memfd. 73 bool IsSealFutureWriteSupported(); 74 75 } // namespace art 76 77 #endif // ART_LIBARTBASE_BASE_MEMFD_H_ 78