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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 | MigrationState *migration_state; | |
27 | QEMUFile *file; | |
28 | int freeze_output; | |
29 | size_t bytes_xfer; | |
30 | size_t xfer_limit; | |
31 | uint8_t *buffer; | |
32 | size_t buffer_size; | |
33 | size_t buffer_capacity; | |
34 | QEMUTimer *timer; | |
35 | } QEMUFileBuffered; | |
36 | ||
37 | #ifdef DEBUG_BUFFERED_FILE | |
38 | #define DPRINTF(fmt, ...) \ | |
39 | do { printf("buffered-file: " fmt, ## __VA_ARGS__); } while (0) | |
40 | #else | |
41 | #define DPRINTF(fmt, ...) \ | |
42 | do { } while (0) | |
43 | #endif | |
44 | ||
45 | static void buffered_append(QEMUFileBuffered *s, | |
46 | const uint8_t *buf, size_t size) | |
47 | { | |
48 | if (size > (s->buffer_capacity - s->buffer_size)) { | |
49 | DPRINTF("increasing buffer capacity from %zu by %zu\n", | |
50 | s->buffer_capacity, size + 1024); | |
51 | ||
52 | s->buffer_capacity += size + 1024; | |
53 | ||
54 | s->buffer = g_realloc(s->buffer, s->buffer_capacity); | |
55 | } | |
56 | ||
57 | memcpy(s->buffer + s->buffer_size, buf, size); | |
58 | s->buffer_size += size; | |
59 | } | |
60 | ||
61 | static ssize_t buffered_flush(QEMUFileBuffered *s) | |
62 | { | |
63 | size_t offset = 0; | |
64 | ssize_t ret = 0; | |
65 | ||
66 | DPRINTF("flushing %zu byte(s) of data\n", s->buffer_size); | |
67 | ||
68 | while (s->bytes_xfer < s->xfer_limit && offset < s->buffer_size) { | |
69 | ||
70 | ret = migrate_fd_put_buffer(s->migration_state, s->buffer + offset, | |
71 | s->buffer_size - offset); | |
72 | if (ret == -EAGAIN) { | |
73 | DPRINTF("backend not ready, freezing\n"); | |
74 | ret = 0; | |
75 | s->freeze_output = 1; | |
76 | break; | |
77 | } | |
78 | ||
79 | if (ret <= 0) { | |
80 | DPRINTF("error flushing data, %zd\n", ret); | |
81 | break; | |
82 | } else { | |
83 | DPRINTF("flushed %zd byte(s)\n", ret); | |
84 | offset += ret; | |
85 | s->bytes_xfer += ret; | |
86 | } | |
87 | } | |
88 | ||
89 | DPRINTF("flushed %zu of %zu byte(s)\n", offset, s->buffer_size); | |
90 | memmove(s->buffer, s->buffer + offset, s->buffer_size - offset); | |
91 | s->buffer_size -= offset; | |
92 | ||
93 | if (ret < 0) { | |
94 | return ret; | |
95 | } | |
96 | return offset; | |
97 | } | |
98 | ||
99 | static int buffered_put_buffer(void *opaque, const uint8_t *buf, int64_t pos, int size) | |
100 | { | |
101 | QEMUFileBuffered *s = opaque; | |
102 | ssize_t error; | |
103 | ||
104 | DPRINTF("putting %d bytes at %" PRId64 "\n", size, pos); | |
105 | ||
106 | error = qemu_file_get_error(s->file); | |
107 | if (error) { | |
108 | DPRINTF("flush when error, bailing: %s\n", strerror(-error)); | |
109 | return error; | |
110 | } | |
111 | ||
112 | DPRINTF("unfreezing output\n"); | |
113 | s->freeze_output = 0; | |
114 | ||
115 | if (size > 0) { | |
116 | DPRINTF("buffering %d bytes\n", size - offset); | |
117 | buffered_append(s, buf, size); | |
118 | } | |
119 | ||
120 | error = buffered_flush(s); | |
121 | if (error < 0) { | |
122 | DPRINTF("buffered flush error. bailing: %s\n", strerror(-error)); | |
123 | return error; | |
124 | } | |
125 | ||
126 | if (pos == 0 && size == 0) { | |
127 | DPRINTF("file is ready\n"); | |
128 | if (!s->freeze_output && s->bytes_xfer < s->xfer_limit) { | |
129 | DPRINTF("notifying client\n"); | |
130 | migrate_fd_put_ready(s->migration_state); | |
131 | } | |
132 | } | |
133 | ||
134 | return size; | |
135 | } | |
136 | ||
137 | static int buffered_close(void *opaque) | |
138 | { | |
139 | QEMUFileBuffered *s = opaque; | |
140 | ssize_t ret = 0; | |
141 | int ret2; | |
142 | ||
143 | DPRINTF("closing\n"); | |
144 | ||
145 | s->xfer_limit = INT_MAX; | |
146 | while (!qemu_file_get_error(s->file) && s->buffer_size) { | |
147 | ret = buffered_flush(s); | |
148 | if (ret < 0) { | |
149 | break; | |
150 | } | |
151 | if (s->freeze_output) { | |
152 | ret = migrate_fd_wait_for_unfreeze(s->migration_state); | |
153 | if (ret < 0) { | |
154 | break; | |
155 | } | |
156 | } | |
157 | } | |
158 | ||
159 | ret2 = migrate_fd_close(s->migration_state); | |
160 | if (ret >= 0) { | |
161 | ret = ret2; | |
162 | } | |
163 | qemu_del_timer(s->timer); | |
164 | qemu_free_timer(s->timer); | |
165 | g_free(s->buffer); | |
166 | g_free(s); | |
167 | ||
168 | return ret; | |
169 | } | |
170 | ||
171 | /* | |
172 | * The meaning of the return values is: | |
173 | * 0: We can continue sending | |
174 | * 1: Time to stop | |
175 | * negative: There has been an error | |
176 | */ | |
177 | static int buffered_rate_limit(void *opaque) | |
178 | { | |
179 | QEMUFileBuffered *s = opaque; | |
180 | int ret; | |
181 | ||
182 | ret = qemu_file_get_error(s->file); | |
183 | if (ret) { | |
184 | return ret; | |
185 | } | |
186 | if (s->freeze_output) | |
187 | return 1; | |
188 | ||
189 | if (s->bytes_xfer > s->xfer_limit) | |
190 | return 1; | |
191 | ||
192 | return 0; | |
193 | } | |
194 | ||
195 | static int64_t buffered_set_rate_limit(void *opaque, int64_t new_rate) | |
196 | { | |
197 | QEMUFileBuffered *s = opaque; | |
198 | if (qemu_file_get_error(s->file)) { | |
199 | goto out; | |
200 | } | |
201 | if (new_rate > SIZE_MAX) { | |
202 | new_rate = SIZE_MAX; | |
203 | } | |
204 | ||
205 | s->xfer_limit = new_rate / 10; | |
206 | ||
207 | out: | |
208 | return s->xfer_limit; | |
209 | } | |
210 | ||
211 | static int64_t buffered_get_rate_limit(void *opaque) | |
212 | { | |
213 | QEMUFileBuffered *s = opaque; | |
214 | ||
215 | return s->xfer_limit; | |
216 | } | |
217 | ||
218 | static void buffered_rate_tick(void *opaque) | |
219 | { | |
220 | QEMUFileBuffered *s = opaque; | |
221 | ||
222 | if (qemu_file_get_error(s->file)) { | |
223 | buffered_close(s); | |
224 | return; | |
225 | } | |
226 | ||
227 | qemu_mod_timer(s->timer, qemu_get_clock_ms(rt_clock) + 100); | |
228 | ||
229 | if (s->freeze_output) | |
230 | return; | |
231 | ||
232 | s->bytes_xfer = 0; | |
233 | ||
234 | buffered_put_buffer(s, NULL, 0, 0); | |
235 | } | |
236 | ||
237 | QEMUFile *qemu_fopen_ops_buffered(MigrationState *migration_state) | |
238 | { | |
239 | QEMUFileBuffered *s; | |
240 | ||
241 | s = g_malloc0(sizeof(*s)); | |
242 | ||
243 | s->migration_state = migration_state; | |
244 | s->xfer_limit = migration_state->bandwidth_limit / 10; | |
245 | ||
246 | s->file = qemu_fopen_ops(s, buffered_put_buffer, NULL, | |
247 | buffered_close, buffered_rate_limit, | |
248 | buffered_set_rate_limit, | |
249 | buffered_get_rate_limit); | |
250 | ||
251 | s->timer = qemu_new_timer_ms(rt_clock, buffered_rate_tick, s); | |
252 | ||
253 | qemu_mod_timer(s->timer, qemu_get_clock_ms(rt_clock) + 100); | |
254 | ||
255 | return s->file; | |
256 | } |