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3719602c PC |
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 |