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| 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 devices, which have our |
| 19 * ashmem-enabled kernel. See ashmem-sim.c for the "fake" tmp-based version, |
| 20 * used by the simulator. |
| 21 */ |
| 22 |
| 23 #include <unistd.h> |
| 24 #include <string.h> |
| 25 #include <sys/types.h> |
| 26 #include <sys/stat.h> |
| 27 #include <sys/ioctl.h> |
| 28 #include <fcntl.h> |
| 29 |
| 30 #include <linux/ashmem.h> |
| 31 #include "ashmem.h" |
| 32 |
| 33 #define ASHMEM_DEVICE "/dev/ashmem" |
| 34 |
| 35 /* |
| 36 * ashmem_create_region - creates a new ashmem region and returns the file |
| 37 * descriptor, or <0 on error |
| 38 * |
| 39 * `name' is an optional label to give the region (visible in /proc/pid/maps) |
| 40 * `size' is the size of the region, in page-aligned bytes |
| 41 */ |
| 42 int ashmem_create_region(const char *name, size_t size) |
| 43 { |
| 44 int fd, ret; |
| 45 |
| 46 fd = open(ASHMEM_DEVICE, O_RDWR); |
| 47 if (fd < 0) |
| 48 return fd; |
| 49 |
| 50 if (name) { |
| 51 char buf[ASHMEM_NAME_LEN]; |
| 52 |
| 53 strlcpy(buf, name, sizeof(buf)); |
| 54 ret = ioctl(fd, ASHMEM_SET_NAME, buf); |
| 55 if (ret < 0) |
| 56 goto error; |
| 57 } |
| 58 |
| 59 ret = ioctl(fd, ASHMEM_SET_SIZE, size); |
| 60 if (ret < 0) |
| 61 goto error; |
| 62 |
| 63 return fd; |
| 64 |
| 65 error: |
| 66 close(fd); |
| 67 return ret; |
| 68 } |
| 69 |
| 70 int ashmem_set_prot_region(int fd, int prot) |
| 71 { |
| 72 return ioctl(fd, ASHMEM_SET_PROT_MASK, prot); |
| 73 } |
| 74 |
| 75 int ashmem_pin_region(int fd, size_t offset, size_t len) |
| 76 { |
| 77 struct ashmem_pin pin = { offset, len }; |
| 78 return ioctl(fd, ASHMEM_PIN, &pin); |
| 79 } |
| 80 |
| 81 int ashmem_unpin_region(int fd, size_t offset, size_t len) |
| 82 { |
| 83 struct ashmem_pin pin = { offset, len }; |
| 84 return ioctl(fd, ASHMEM_UNPIN, &pin); |
| 85 } |
| 86 |
| 87 int ashmem_get_size_region(int fd) |
| 88 { |
| 89 return ioctl(fd, ASHMEM_GET_SIZE, NULL); |
| 90 } |
| 91 |
| 92 int ashmem_purge_all(void) |
| 93 { |
| 94 const int fd = open(ASHMEM_DEVICE, O_RDWR); |
| 95 if (fd < 0) |
| 96 return fd; |
| 97 const int ret = ioctl(fd, ASHMEM_PURGE_ALL_CACHES, 0); |
| 98 close(fd); |
| 99 return ret; |
| 100 } |
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