1 /* 2 * Copyright (C) 2008 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 /* 18 * Implementation of the user-space ashmem API for the simulator, which lacks 19 * an ashmem-enabled kernel. See ashmem-dev.c for the real ashmem-based version. 20 */ 21 22 #include <errno.h> 23 #include <fcntl.h> 24 #include <limits.h> 25 #include <stdbool.h> 26 #include <stdio.h> 27 #include <stdlib.h> 28 #include <string.h> 29 #include <sys/stat.h> 30 #include <sys/types.h> 31 #include <time.h> 32 #include <unistd.h> 33 34 #include <cutils/ashmem.h> 35 #include <utils/Compat.h> 36 37 #ifndef __unused 38 #define __unused __attribute__((__unused__)) 39 #endif 40 41 int ashmem_create_region(const char *ignored __unused, size_t size) 42 { 43 char template[PATH_MAX]; 44 snprintf(template, sizeof(template), "/tmp/android-ashmem-%d-XXXXXXXXX", getpid()); 45 int fd = mkstemp(template); 46 if (fd == -1) return -1; 47 48 unlink(template); 49 50 if (TEMP_FAILURE_RETRY(ftruncate(fd, size)) == -1) { 51 close(fd); 52 return -1; 53 } 54 55 return fd; 56 } 57 58 int ashmem_set_prot_region(int fd __unused, int prot __unused) 59 { 60 return 0; 61 } 62 63 int ashmem_pin_region(int fd __unused, size_t offset __unused, size_t len __unused) 64 { 65 return ASHMEM_NOT_PURGED; 66 } 67 68 int ashmem_unpin_region(int fd __unused, size_t offset __unused, size_t len __unused) 69 { 70 return ASHMEM_IS_UNPINNED; 71 } 72 73 int ashmem_get_size_region(int fd) 74 { 75 struct stat buf; 76 int result = fstat(fd, &buf); 77 if (result == -1) { 78 return -1; 79 } 80 81 /* 82 * Check if this is an "ashmem" region. 83 * TODO: This is very hacky, and can easily break. 84 * We need some reliable indicator. 85 */ 86 if (!(buf.st_nlink == 0 && S_ISREG(buf.st_mode))) { 87 errno = ENOTTY; 88 return -1; 89 } 90 91 return buf.st_size; 92 } 93
