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1 | /* | |
2 | * QEMU buffered QEMUFile | |
3 | * | |
4 | * Copyright IBM, Corp. 2008 | |
5 | * | |
6 | * Authors: | |
7 | * Anthony Liguori <aliguori@us.ibm.com> | |
8 | * | |
9 | * This work is licensed under the terms of the GNU GPL, version 2. See | |
10 | * the COPYING file in the top-level directory. | |
11 | * | |
12 | * Contributions after 2012-01-13 are licensed under the terms of the | |
13 | * GNU GPL, version 2 or (at your option) any later version. | |
14 | */ | |
15 | ||
16 | #include "qemu-common.h" | |
17 | #include "hw/hw.h" | |
18 | #include "qemu-timer.h" | |
19 | #include "qemu-char.h" | |
20 | #include "buffered_file.h" | |
21 | ||
22 | //#define DEBUG_BUFFERED_FILE | |
23 | ||
24 | typedef struct QEMUFileBuffered | |
25 | { | |
26 | BufferedPutFunc *put_buffer; | |
27 | BufferedPutReadyFunc *put_ready; | |
28 | BufferedWaitForUnfreezeFunc *wait_for_unfreeze; | |
29 | BufferedCloseFunc *close; | |
30 | void *opaque; | |
31 | QEMUFile *file; | |
32 | int freeze_output; | |
33 | size_t bytes_xfer; | |
34 | size_t xfer_limit; | |
35 | uint8_t *buffer; | |
36 | size_t buffer_size; | |
37 | size_t buffer_capacity; | |
38 | QEMUTimer *timer; | |
39 | } QEMUFileBuffered; | |
40 | ||
41 | #ifdef DEBUG_BUFFERED_FILE | |
42 | #define DPRINTF(fmt, ...) \ | |
43 | do { printf("buffered-file: " fmt, ## __VA_ARGS__); } while (0) | |
44 | #else | |
45 | #define DPRINTF(fmt, ...) \ | |
46 | do { } while (0) | |
47 | #endif | |
48 | ||
49 | static void buffered_append(QEMUFileBuffered *s, | |
50 | const uint8_t *buf, size_t size) | |
51 | { | |
52 | if (size > (s->buffer_capacity - s->buffer_size)) { | |
53 | void *tmp; | |
54 | ||
55 | DPRINTF("increasing buffer capacity from %zu by %zu\n", | |
56 | s->buffer_capacity, size + 1024); | |
57 | ||
58 | s->buffer_capacity += size + 1024; | |
59 | ||
60 | tmp = g_realloc(s->buffer, s->buffer_capacity); | |
61 | if (tmp == NULL) { | |
62 | fprintf(stderr, "qemu file buffer expansion failed\n"); | |
63 | exit(1); | |
64 | } | |
65 | ||
66 | s->buffer = tmp; | |
67 | } | |
68 | ||
69 | memcpy(s->buffer + s->buffer_size, buf, size); | |
70 | s->buffer_size += size; | |
71 | } | |
72 | ||
73 | static void buffered_flush(QEMUFileBuffered *s) | |
74 | { | |
75 | size_t offset = 0; | |
76 | int error; | |
77 | ||
78 | error = qemu_file_get_error(s->file); | |
79 | if (error != 0) { | |
80 | DPRINTF("flush when error, bailing: %s\n", strerror(-error)); | |
81 | return; | |
82 | } | |
83 | ||
84 | DPRINTF("flushing %zu byte(s) of data\n", s->buffer_size); | |
85 | ||
86 | while (offset < s->buffer_size) { | |
87 | ssize_t ret; | |
88 | ||
89 | ret = s->put_buffer(s->opaque, s->buffer + offset, | |
90 | s->buffer_size - offset); | |
91 | if (ret == -EAGAIN) { | |
92 | DPRINTF("backend not ready, freezing\n"); | |
93 | s->freeze_output = 1; | |
94 | break; | |
95 | } | |
96 | ||
97 | if (ret <= 0) { | |
98 | DPRINTF("error flushing data, %zd\n", ret); | |
99 | qemu_file_set_error(s->file, ret); | |
100 | break; | |
101 | } else { | |
102 | DPRINTF("flushed %zd byte(s)\n", ret); | |
103 | offset += ret; | |
104 | } | |
105 | } | |
106 | ||
107 | DPRINTF("flushed %zu of %zu byte(s)\n", offset, s->buffer_size); | |
108 | memmove(s->buffer, s->buffer + offset, s->buffer_size - offset); | |
109 | s->buffer_size -= offset; | |
110 | } | |
111 | ||
112 | static int buffered_put_buffer(void *opaque, const uint8_t *buf, int64_t pos, int size) | |
113 | { | |
114 | QEMUFileBuffered *s = opaque; | |
115 | int offset = 0, error; | |
116 | ssize_t ret; | |
117 | ||
118 | DPRINTF("putting %d bytes at %" PRId64 "\n", size, pos); | |
119 | ||
120 | error = qemu_file_get_error(s->file); | |
121 | if (error) { | |
122 | DPRINTF("flush when error, bailing: %s\n", strerror(-error)); | |
123 | return error; | |
124 | } | |
125 | ||
126 | DPRINTF("unfreezing output\n"); | |
127 | s->freeze_output = 0; | |
128 | ||
129 | buffered_flush(s); | |
130 | ||
131 | while (!s->freeze_output && offset < size) { | |
132 | if (s->bytes_xfer > s->xfer_limit) { | |
133 | DPRINTF("transfer limit exceeded when putting\n"); | |
134 | break; | |
135 | } | |
136 | ||
137 | ret = s->put_buffer(s->opaque, buf + offset, size - offset); | |
138 | if (ret == -EAGAIN) { | |
139 | DPRINTF("backend not ready, freezing\n"); | |
140 | s->freeze_output = 1; | |
141 | break; | |
142 | } | |
143 | ||
144 | if (ret <= 0) { | |
145 | DPRINTF("error putting\n"); | |
146 | qemu_file_set_error(s->file, ret); | |
147 | offset = -EINVAL; | |
148 | break; | |
149 | } | |
150 | ||
151 | DPRINTF("put %zd byte(s)\n", ret); | |
152 | offset += ret; | |
153 | s->bytes_xfer += ret; | |
154 | } | |
155 | ||
156 | if (offset >= 0) { | |
157 | DPRINTF("buffering %d bytes\n", size - offset); | |
158 | buffered_append(s, buf + offset, size - offset); | |
159 | offset = size; | |
160 | } | |
161 | ||
162 | if (pos == 0 && size == 0) { | |
163 | DPRINTF("file is ready\n"); | |
164 | if (s->bytes_xfer <= s->xfer_limit) { | |
165 | DPRINTF("notifying client\n"); | |
166 | s->put_ready(s->opaque); | |
167 | } | |
168 | } | |
169 | ||
170 | return offset; | |
171 | } | |
172 | ||
173 | static int buffered_close(void *opaque) | |
174 | { | |
175 | QEMUFileBuffered *s = opaque; | |
176 | int ret; | |
177 | ||
178 | DPRINTF("closing\n"); | |
179 | ||
180 | while (!qemu_file_get_error(s->file) && s->buffer_size) { | |
181 | buffered_flush(s); | |
182 | if (s->freeze_output) | |
183 | s->wait_for_unfreeze(s->opaque); | |
184 | } | |
185 | ||
186 | ret = s->close(s->opaque); | |
187 | ||
188 | qemu_del_timer(s->timer); | |
189 | qemu_free_timer(s->timer); | |
190 | g_free(s->buffer); | |
191 | g_free(s); | |
192 | ||
193 | return ret; | |
194 | } | |
195 | ||
196 | /* | |
197 | * The meaning of the return values is: | |
198 | * 0: We can continue sending | |
199 | * 1: Time to stop | |
200 | * negative: There has been an error | |
201 | */ | |
202 | static int buffered_rate_limit(void *opaque) | |
203 | { | |
204 | QEMUFileBuffered *s = opaque; | |
205 | int ret; | |
206 | ||
207 | ret = qemu_file_get_error(s->file); | |
208 | if (ret) { | |
209 | return ret; | |
210 | } | |
211 | if (s->freeze_output) | |
212 | return 1; | |
213 | ||
214 | if (s->bytes_xfer > s->xfer_limit) | |
215 | return 1; | |
216 | ||
217 | return 0; | |
218 | } | |
219 | ||
220 | static int64_t buffered_set_rate_limit(void *opaque, int64_t new_rate) | |
221 | { | |
222 | QEMUFileBuffered *s = opaque; | |
223 | if (qemu_file_get_error(s->file)) { | |
224 | goto out; | |
225 | } | |
226 | if (new_rate > SIZE_MAX) { | |
227 | new_rate = SIZE_MAX; | |
228 | } | |
229 | ||
230 | s->xfer_limit = new_rate / 10; | |
231 | ||
232 | out: | |
233 | return s->xfer_limit; | |
234 | } | |
235 | ||
236 | static int64_t buffered_get_rate_limit(void *opaque) | |
237 | { | |
238 | QEMUFileBuffered *s = opaque; | |
239 | ||
240 | return s->xfer_limit; | |
241 | } | |
242 | ||
243 | static void buffered_rate_tick(void *opaque) | |
244 | { | |
245 | QEMUFileBuffered *s = opaque; | |
246 | ||
247 | if (qemu_file_get_error(s->file)) { | |
248 | buffered_close(s); | |
249 | return; | |
250 | } | |
251 | ||
252 | qemu_mod_timer(s->timer, qemu_get_clock_ms(rt_clock) + 100); | |
253 | ||
254 | if (s->freeze_output) | |
255 | return; | |
256 | ||
257 | s->bytes_xfer = 0; | |
258 | ||
259 | buffered_flush(s); | |
260 | ||
261 | /* Add some checks around this */ | |
262 | s->put_ready(s->opaque); | |
263 | } | |
264 | ||
265 | QEMUFile *qemu_fopen_ops_buffered(void *opaque, | |
266 | size_t bytes_per_sec, | |
267 | BufferedPutFunc *put_buffer, | |
268 | BufferedPutReadyFunc *put_ready, | |
269 | BufferedWaitForUnfreezeFunc *wait_for_unfreeze, | |
270 | BufferedCloseFunc *close) | |
271 | { | |
272 | QEMUFileBuffered *s; | |
273 | ||
274 | s = g_malloc0(sizeof(*s)); | |
275 | ||
276 | s->opaque = opaque; | |
277 | s->xfer_limit = bytes_per_sec / 10; | |
278 | s->put_buffer = put_buffer; | |
279 | s->put_ready = put_ready; | |
280 | s->wait_for_unfreeze = wait_for_unfreeze; | |
281 | s->close = close; | |
282 | ||
283 | s->file = qemu_fopen_ops(s, buffered_put_buffer, NULL, | |
284 | buffered_close, buffered_rate_limit, | |
285 | buffered_set_rate_limit, | |
286 | buffered_get_rate_limit); | |
287 | ||
288 | s->timer = qemu_new_timer_ms(rt_clock, buffered_rate_tick, s); | |
289 | ||
290 | qemu_mod_timer(s->timer, qemu_get_clock_ms(rt_clock) + 100); | |
291 | ||
292 | return s->file; | |
293 | } |