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