Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Newer
Older
100644 283 lines (222 sloc) 6.576 kb
68396ea @rmustacc Initial commit of d32e8d0b8d9e0ef7cf7ab2e74548982972789dfc from qemu-kvm
rmustacc authored
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 "sysemu.h"
18 #include "qemu-char.h"
19 #include "buffered_file.h"
20
21 //#define DEBUG_BUFFERED_FILE
22
23 typedef struct QEMUFileBuffered
24 {
25 BufferedPutFunc *put_buffer;
26 BufferedPutReadyFunc *put_ready;
27 BufferedWaitForUnfreezeFunc *wait_for_unfreeze;
28 BufferedCloseFunc *close;
29 void *opaque;
30 QEMUFile *file;
31 int has_error;
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 = qemu_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
77 if (s->has_error) {
78 DPRINTF("flush when error, bailing\n");
79 return;
80 }
81
82 DPRINTF("flushing %zu byte(s) of data\n", s->buffer_size);
83
84 while (offset < s->buffer_size) {
85 ssize_t ret;
86
87 ret = s->put_buffer(s->opaque, s->buffer + offset,
88 s->buffer_size - offset);
89 if (ret == -EAGAIN) {
90 DPRINTF("backend not ready, freezing\n");
91 s->freeze_output = 1;
92 break;
93 }
94
95 if (ret <= 0) {
96 DPRINTF("error flushing data, %zd\n", ret);
97 s->has_error = 1;
98 break;
99 } else {
100 DPRINTF("flushed %zd byte(s)\n", ret);
101 offset += ret;
102 }
103 }
104
105 DPRINTF("flushed %zu of %zu byte(s)\n", offset, s->buffer_size);
106 memmove(s->buffer, s->buffer + offset, s->buffer_size - offset);
107 s->buffer_size -= offset;
108 }
109
110 static int buffered_put_buffer(void *opaque, const uint8_t *buf, int64_t pos, int size)
111 {
112 QEMUFileBuffered *s = opaque;
113 int offset = 0;
114 ssize_t ret;
115
116 DPRINTF("putting %d bytes at %" PRId64 "\n", size, pos);
117
118 if (s->has_error) {
119 DPRINTF("flush when error, bailing\n");
120 return -EINVAL;
121 }
122
123 DPRINTF("unfreezing output\n");
124 s->freeze_output = 0;
125
126 buffered_flush(s);
127
128 while (!s->freeze_output && offset < size) {
129 if (s->bytes_xfer > s->xfer_limit) {
130 DPRINTF("transfer limit exceeded when putting\n");
131 break;
132 }
133
134 ret = s->put_buffer(s->opaque, buf + offset, size - offset);
135 if (ret == -EAGAIN) {
136 DPRINTF("backend not ready, freezing\n");
137 s->freeze_output = 1;
138 break;
139 }
140
141 if (ret <= 0) {
142 DPRINTF("error putting\n");
143 s->has_error = 1;
144 offset = -EINVAL;
145 break;
146 }
147
148 DPRINTF("put %zd byte(s)\n", ret);
149 offset += ret;
150 s->bytes_xfer += ret;
151 }
152
153 if (offset >= 0) {
154 DPRINTF("buffering %d bytes\n", size - offset);
155 buffered_append(s, buf + offset, size - offset);
156 offset = size;
157 }
158
159 if (pos == 0 && size == 0) {
160 DPRINTF("file is ready\n");
161 if (s->bytes_xfer <= s->xfer_limit) {
162 DPRINTF("notifying client\n");
163 s->put_ready(s->opaque);
164 }
165 }
166
167 return offset;
168 }
169
170 static int buffered_close(void *opaque)
171 {
172 QEMUFileBuffered *s = opaque;
173 int ret;
174
175 DPRINTF("closing\n");
176
177 while (!s->has_error && s->buffer_size) {
178 buffered_flush(s);
179 if (s->freeze_output)
180 s->wait_for_unfreeze(s);
181 }
182
183 ret = s->close(s->opaque);
184
185 qemu_del_timer(s->timer);
186 qemu_free_timer(s->timer);
187 qemu_free(s->buffer);
188 qemu_free(s);
189
190 return ret;
191 }
192
193 static int buffered_rate_limit(void *opaque)
194 {
195 QEMUFileBuffered *s = opaque;
196
197 if (s->has_error)
198 return 0;
199
200 if (s->freeze_output)
201 return 1;
202
203 if (s->bytes_xfer > s->xfer_limit)
204 return 1;
205
206 return 0;
207 }
208
209 static int64_t buffered_set_rate_limit(void *opaque, int64_t new_rate)
210 {
211 QEMUFileBuffered *s = opaque;
212 if (s->has_error)
213 goto out;
214
215 if (new_rate > SIZE_MAX) {
216 new_rate = SIZE_MAX;
217 }
218
219 s->xfer_limit = new_rate / 10;
220
221 out:
222 return s->xfer_limit;
223 }
224
225 static int64_t buffered_get_rate_limit(void *opaque)
226 {
227 QEMUFileBuffered *s = opaque;
228
229 return s->xfer_limit;
230 }
231
232 static void buffered_rate_tick(void *opaque)
233 {
234 QEMUFileBuffered *s = opaque;
235
236 if (s->has_error) {
237 buffered_close(s);
238 return;
239 }
240
241 qemu_mod_timer(s->timer, qemu_get_clock(rt_clock) + 100);
242
243 if (s->freeze_output)
244 return;
245
246 s->bytes_xfer = 0;
247
248 buffered_flush(s);
249
250 /* Add some checks around this */
251 s->put_ready(s->opaque);
252 }
253
254 QEMUFile *qemu_fopen_ops_buffered(void *opaque,
255 size_t bytes_per_sec,
256 BufferedPutFunc *put_buffer,
257 BufferedPutReadyFunc *put_ready,
258 BufferedWaitForUnfreezeFunc *wait_for_unfreeze,
259 BufferedCloseFunc *close)
260 {
261 QEMUFileBuffered *s;
262
263 s = qemu_mallocz(sizeof(*s));
264
265 s->opaque = opaque;
266 s->xfer_limit = bytes_per_sec / 10;
267 s->put_buffer = put_buffer;
268 s->put_ready = put_ready;
269 s->wait_for_unfreeze = wait_for_unfreeze;
270 s->close = close;
271
272 s->file = qemu_fopen_ops(s, buffered_put_buffer, NULL,
273 buffered_close, buffered_rate_limit,
274 buffered_set_rate_limit,
275 buffered_get_rate_limit);
276
277 s->timer = qemu_new_timer(rt_clock, buffered_rate_tick, s);
278
279 qemu_mod_timer(s->timer, qemu_get_clock(rt_clock) + 100);
280
281 return s->file;
282 }
Something went wrong with that request. Please try again.