| 1 | /* Copyright (C) 2010-2020 The RetroArch team |
| 2 | * |
| 3 | * --------------------------------------------------------------------------------------- |
| 4 | * The following license statement only applies to this file (nbio_linux.c). |
| 5 | * --------------------------------------------------------------------------------------- |
| 6 | * |
| 7 | * Permission is hereby granted, free of charge, |
| 8 | * to any person obtaining a copy of this software and associated documentation files (the "Software"), |
| 9 | * to deal in the Software without restriction, including without limitation the rights to |
| 10 | * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, |
| 11 | * and to permit persons to whom the Software is furnished to do so, subject to the following conditions: |
| 12 | * |
| 13 | * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. |
| 14 | * |
| 15 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, |
| 16 | * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| 17 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. |
| 18 | * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, |
| 19 | * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| 20 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
| 21 | */ |
| 22 | |
| 23 | #include <file/nbio.h> |
| 24 | |
| 25 | #if defined(__linux__) |
| 26 | |
| 27 | #ifndef _GNU_SOURCE |
| 28 | #define _GNU_SOURCE |
| 29 | #endif |
| 30 | #include <stdio.h> |
| 31 | #include <stdlib.h> |
| 32 | #include <stdint.h> |
| 33 | #include <string.h> |
| 34 | #include <time.h> |
| 35 | |
| 36 | #include <unistd.h> |
| 37 | #include <fcntl.h> |
| 38 | #include <sys/syscall.h> |
| 39 | #include <linux/aio_abi.h> |
| 40 | |
| 41 | struct nbio_linux_t |
| 42 | { |
| 43 | void* ptr; |
| 44 | aio_context_t ctx; |
| 45 | struct iocb cb; |
| 46 | size_t len; |
| 47 | int fd; |
| 48 | bool busy; |
| 49 | }; |
| 50 | |
| 51 | /* there's also a Unix AIO thingy, but it's not in glibc |
| 52 | * and we don't want more dependencies */ |
| 53 | |
| 54 | static int io_setup(unsigned nr, aio_context_t * ctxp) |
| 55 | { |
| 56 | return syscall(__NR_io_setup, nr, ctxp); |
| 57 | } |
| 58 | |
| 59 | static int io_destroy(aio_context_t ctx) |
| 60 | { |
| 61 | return syscall(__NR_io_destroy, ctx); |
| 62 | } |
| 63 | |
| 64 | static int io_submit(aio_context_t ctx, long nr, struct iocb ** cbp) |
| 65 | { |
| 66 | return syscall(__NR_io_submit, ctx, nr, cbp); |
| 67 | } |
| 68 | |
| 69 | static int io_cancel(aio_context_t ctx, struct iocb * iocb, struct io_event * result) |
| 70 | { |
| 71 | return syscall(__NR_io_cancel, ctx, iocb, result); |
| 72 | } |
| 73 | |
| 74 | static int io_getevents(aio_context_t ctx, long min_nr, long nr, |
| 75 | struct io_event * events, struct timespec * timeout) |
| 76 | { |
| 77 | return syscall(__NR_io_getevents, ctx, min_nr, nr, events, timeout); |
| 78 | } |
| 79 | |
| 80 | static void nbio_begin_op(struct nbio_linux_t* handle, uint16_t op) |
| 81 | { |
| 82 | struct iocb * cbp = &handle->cb; |
| 83 | |
| 84 | memset(&handle->cb, 0, sizeof(handle->cb)); |
| 85 | |
| 86 | handle->cb.aio_fildes = handle->fd; |
| 87 | handle->cb.aio_lio_opcode = op; |
| 88 | |
| 89 | handle->cb.aio_buf = (uint64_t)(uintptr_t)handle->ptr; |
| 90 | handle->cb.aio_offset = 0; |
| 91 | handle->cb.aio_nbytes = handle->len; |
| 92 | |
| 93 | if (io_submit(handle->ctx, 1, &cbp) != 1) |
| 94 | abort(); |
| 95 | |
| 96 | handle->busy = true; |
| 97 | } |
| 98 | |
| 99 | static void *nbio_linux_open(const char * filename, unsigned mode) |
| 100 | { |
| 101 | static const int o_flags[] = { O_RDONLY, O_RDWR|O_CREAT|O_TRUNC, O_RDWR, O_RDONLY, O_RDWR|O_CREAT|O_TRUNC }; |
| 102 | |
| 103 | aio_context_t ctx = 0; |
| 104 | struct nbio_linux_t* handle = NULL; |
| 105 | int fd = open(filename, o_flags[mode]|O_CLOEXEC, 0644); |
| 106 | if (fd < 0) |
| 107 | return NULL; |
| 108 | |
| 109 | if (io_setup(128, &ctx) < 0) |
| 110 | { |
| 111 | close(fd); |
| 112 | return NULL; |
| 113 | } |
| 114 | |
| 115 | handle = (struct nbio_linux_t*)malloc(sizeof(struct nbio_linux_t)); |
| 116 | handle->fd = fd; |
| 117 | handle->ctx = ctx; |
| 118 | handle->len = lseek(fd, 0, SEEK_END); |
| 119 | handle->ptr = malloc(handle->len); |
| 120 | handle->busy = false; |
| 121 | |
| 122 | return handle; |
| 123 | } |
| 124 | |
| 125 | static void nbio_linux_begin_read(void *data) |
| 126 | { |
| 127 | struct nbio_linux_t* handle = (struct nbio_linux_t*)data; |
| 128 | if (handle) |
| 129 | nbio_begin_op(handle, IOCB_CMD_PREAD); |
| 130 | } |
| 131 | |
| 132 | static void nbio_linux_begin_write(void *data) |
| 133 | { |
| 134 | struct nbio_linux_t* handle = (struct nbio_linux_t*)data; |
| 135 | if (handle) |
| 136 | nbio_begin_op(handle, IOCB_CMD_PWRITE); |
| 137 | } |
| 138 | |
| 139 | static bool nbio_linux_iterate(void *data) |
| 140 | { |
| 141 | struct nbio_linux_t* handle = (struct nbio_linux_t*)data; |
| 142 | if (!handle) |
| 143 | return false; |
| 144 | if (handle->busy) |
| 145 | { |
| 146 | struct io_event ev; |
| 147 | if (io_getevents(handle->ctx, 0, 1, &ev, NULL) == 1) |
| 148 | handle->busy = false; |
| 149 | } |
| 150 | return !handle->busy; |
| 151 | } |
| 152 | |
| 153 | static void nbio_linux_resize(void *data, size_t len) |
| 154 | { |
| 155 | struct nbio_linux_t* handle = (struct nbio_linux_t*)data; |
| 156 | if (!handle) |
| 157 | return; |
| 158 | |
| 159 | /* This works perfectly fine if this check is removed, but it |
| 160 | * won't work on other nbio implementations */ |
| 161 | /* therefore, it's blocked so nobody accidentally relies on it */ |
| 162 | if (len < handle->len) |
| 163 | abort(); |
| 164 | |
| 165 | if (ftruncate(handle->fd, len) != 0) |
| 166 | abort(); /* this one returns void and I can't find any other way |
| 167 | for it to report failure */ |
| 168 | |
| 169 | handle->ptr = realloc(handle->ptr, len); |
| 170 | handle->len = len; |
| 171 | } |
| 172 | |
| 173 | static void *nbio_linux_get_ptr(void *data, size_t* len) |
| 174 | { |
| 175 | struct nbio_linux_t* handle = (struct nbio_linux_t*)data; |
| 176 | if (!handle) |
| 177 | return NULL; |
| 178 | if (len) |
| 179 | *len = handle->len; |
| 180 | if (!handle->busy) |
| 181 | return handle->ptr; |
| 182 | return NULL; |
| 183 | } |
| 184 | |
| 185 | static void nbio_linux_cancel(void *data) |
| 186 | { |
| 187 | struct nbio_linux_t* handle = (struct nbio_linux_t*)data; |
| 188 | if (!handle) |
| 189 | return; |
| 190 | |
| 191 | if (handle->busy) |
| 192 | { |
| 193 | struct io_event ev; |
| 194 | io_cancel(handle->ctx, &handle->cb, &ev); |
| 195 | handle->busy = false; |
| 196 | } |
| 197 | } |
| 198 | |
| 199 | static void nbio_linux_free(void *data) |
| 200 | { |
| 201 | struct nbio_linux_t* handle = (struct nbio_linux_t*)data; |
| 202 | if (!handle) |
| 203 | return; |
| 204 | |
| 205 | io_destroy(handle->ctx); |
| 206 | close(handle->fd); |
| 207 | free(handle->ptr); |
| 208 | free(handle); |
| 209 | } |
| 210 | |
| 211 | nbio_intf_t nbio_linux = { |
| 212 | nbio_linux_open, |
| 213 | nbio_linux_begin_read, |
| 214 | nbio_linux_begin_write, |
| 215 | nbio_linux_iterate, |
| 216 | nbio_linux_resize, |
| 217 | nbio_linux_get_ptr, |
| 218 | nbio_linux_cancel, |
| 219 | nbio_linux_free, |
| 220 | "nbio_linux", |
| 221 | }; |
| 222 | #else |
| 223 | nbio_intf_t nbio_linux = { |
| 224 | NULL, |
| 225 | NULL, |
| 226 | NULL, |
| 227 | NULL, |
| 228 | NULL, |
| 229 | NULL, |
| 230 | NULL, |
| 231 | NULL, |
| 232 | "nbio_linux", |
| 233 | }; |
| 234 | |
| 235 | #endif |