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1.1 root 1: /*
2: * QEMU buffered QEMUFile
3: *
4: * Copyright IBM, Corp. 2008
5: *
6: * Authors:
7: * Anthony Liguori <[email protected]>
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 %ld by %ld\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 %ld 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, %ld\n", ret);
97: s->has_error = 1;
98: break;
99: } else {
100: dprintf("flushed %ld byte(s)\n", ret);
101: offset += ret;
102: }
103: }
104:
105: dprintf("flushed %ld of %ld 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 %ld bytes at %Ld\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 %ld byte(s)\n", ret);
149: offset += ret;
150: s->bytes_xfer += ret;
151: }
152:
153: if (offset >= 0) {
154: dprintf("buffering %ld bytes\n", size - offset);
155: buffered_append(s, buf + offset, size - offset);
156: offset = size;
157: }
158:
159: return offset;
160: }
161:
162: static int buffered_close(void *opaque)
163: {
164: QEMUFileBuffered *s = opaque;
165: int ret;
166:
167: dprintf("closing\n");
168:
169: while (!s->has_error && s->buffer_size) {
170: buffered_flush(s);
171: if (s->freeze_output)
172: s->wait_for_unfreeze(s);
173: }
174:
175: ret = s->close(s->opaque);
176:
177: qemu_del_timer(s->timer);
178: qemu_free_timer(s->timer);
179: qemu_free(s->buffer);
180: qemu_free(s);
181:
182: return ret;
183: }
184:
185: static int buffered_rate_limit(void *opaque)
186: {
187: QEMUFileBuffered *s = opaque;
188:
189: if (s->has_error)
190: return 0;
191:
192: if (s->freeze_output)
193: return 1;
194:
195: if (s->bytes_xfer > s->xfer_limit)
196: return 1;
197:
198: return 0;
199: }
200:
201: static void buffered_rate_tick(void *opaque)
202: {
203: QEMUFileBuffered *s = opaque;
204:
205: if (s->has_error)
206: return;
207:
208: qemu_mod_timer(s->timer, qemu_get_clock(rt_clock) + 100);
209:
210: if (s->freeze_output)
211: return;
212:
213: s->bytes_xfer = 0;
214:
215: buffered_flush(s);
216:
217: /* Add some checks around this */
218: s->put_ready(s->opaque);
219: }
220:
221: QEMUFile *qemu_fopen_ops_buffered(void *opaque,
222: size_t bytes_per_sec,
223: BufferedPutFunc *put_buffer,
224: BufferedPutReadyFunc *put_ready,
225: BufferedWaitForUnfreezeFunc *wait_for_unfreeze,
226: BufferedCloseFunc *close)
227: {
228: QEMUFileBuffered *s;
229:
230: s = qemu_mallocz(sizeof(*s));
231:
232: s->opaque = opaque;
233: s->xfer_limit = bytes_per_sec / 10;
234: s->put_buffer = put_buffer;
235: s->put_ready = put_ready;
236: s->wait_for_unfreeze = wait_for_unfreeze;
237: s->close = close;
238:
239: s->file = qemu_fopen_ops(s, buffered_put_buffer, NULL,
240: buffered_close, buffered_rate_limit);
241:
242: s->timer = qemu_new_timer(rt_clock, buffered_rate_tick, s);
243:
244: qemu_mod_timer(s->timer, qemu_get_clock(rt_clock) + 100);
245:
246: return s->file;
247: }
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