Merge branch 'stable-0.11' of git://git.sv.gnu.org/qemu into stable-0.11
[qemu-kvm/fedora.git] / buffered_file.c
blob63de17d8fda2b09407bb93141fa9bfe443a2c40d
1 /*
2 * QEMU buffered QEMUFile
4 * Copyright IBM, Corp. 2008
6 * Authors:
7 * Anthony Liguori <aliguori@us.ibm.com>
9 * This work is licensed under the terms of the GNU GPL, version 2. See
10 * the COPYING file in the top-level directory.
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"
21 //#define DEBUG_BUFFERED_FILE
23 typedef struct QEMUFileBuffered
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;
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
49 static void buffered_append(QEMUFileBuffered *s,
50 const uint8_t *buf, size_t size)
52 if (size > (s->buffer_capacity - s->buffer_size)) {
53 void *tmp;
55 dprintf("increasing buffer capacity from %ld by %ld\n",
56 s->buffer_capacity, size + 1024);
58 s->buffer_capacity += size + 1024;
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);
66 s->buffer = tmp;
69 memcpy(s->buffer + s->buffer_size, buf, size);
70 s->buffer_size += size;
73 static void buffered_flush(QEMUFileBuffered *s)
75 size_t offset = 0;
77 if (s->has_error) {
78 dprintf("flush when error, bailing\n");
79 return;
82 dprintf("flushing %ld byte(s) of data\n", s->buffer_size);
84 while (offset < s->buffer_size) {
85 ssize_t ret;
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;
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;
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;
110 static int buffered_put_buffer(void *opaque, const uint8_t *buf, int64_t pos, int size)
112 QEMUFileBuffered *s = opaque;
113 int offset = 0;
114 ssize_t ret;
116 dprintf("putting %d bytes at %" PRId64 "\n", size, pos);
118 if (s->has_error) {
119 dprintf("flush when error, bailing\n");
120 return -EINVAL;
123 dprintf("unfreezing output\n");
124 s->freeze_output = 0;
126 buffered_flush(s);
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;
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;
141 if (ret <= 0) {
142 dprintf("error putting\n");
143 s->has_error = 1;
144 offset = -EINVAL;
145 break;
148 dprintf("put %ld byte(s)\n", ret);
149 offset += ret;
150 s->bytes_xfer += ret;
153 if (offset >= 0) {
154 dprintf("buffering %d bytes\n", size - offset);
155 buffered_append(s, buf + offset, size - offset);
156 offset = size;
159 return offset;
162 static int buffered_close(void *opaque)
164 QEMUFileBuffered *s = opaque;
165 int ret;
167 dprintf("closing\n");
169 while (!s->has_error && s->buffer_size) {
170 buffered_flush(s);
171 if (s->freeze_output)
172 s->wait_for_unfreeze(s);
175 ret = s->close(s->opaque);
177 qemu_del_timer(s->timer);
178 qemu_free_timer(s->timer);
179 qemu_free(s->buffer);
180 qemu_free(s);
182 return ret;
185 static int buffered_rate_limit(void *opaque)
187 QEMUFileBuffered *s = opaque;
189 if (s->has_error)
190 return 0;
192 if (s->freeze_output)
193 return 1;
195 if (s->bytes_xfer > s->xfer_limit)
196 return 1;
198 return 0;
201 static size_t buffered_set_rate_limit(void *opaque, size_t new_rate)
203 QEMUFileBuffered *s = opaque;
205 if (s->has_error)
206 goto out;
208 s->xfer_limit = new_rate / 10;
210 out:
211 return s->xfer_limit;
214 static void buffered_rate_tick(void *opaque)
216 QEMUFileBuffered *s = opaque;
218 if (s->has_error)
219 return;
221 qemu_mod_timer(s->timer, qemu_get_clock(rt_clock) + 100);
223 if (s->freeze_output)
224 return;
226 s->bytes_xfer = 0;
228 buffered_flush(s);
230 /* Add some checks around this */
231 s->put_ready(s->opaque);
234 QEMUFile *qemu_fopen_ops_buffered(void *opaque,
235 size_t bytes_per_sec,
236 BufferedPutFunc *put_buffer,
237 BufferedPutReadyFunc *put_ready,
238 BufferedWaitForUnfreezeFunc *wait_for_unfreeze,
239 BufferedCloseFunc *close)
241 QEMUFileBuffered *s;
243 s = qemu_mallocz(sizeof(*s));
245 s->opaque = opaque;
246 s->xfer_limit = bytes_per_sec / 10;
247 s->put_buffer = put_buffer;
248 s->put_ready = put_ready;
249 s->wait_for_unfreeze = wait_for_unfreeze;
250 s->close = close;
252 s->file = qemu_fopen_ops(s, buffered_put_buffer, NULL,
253 buffered_close, buffered_rate_limit,
254 buffered_set_rate_limit);
256 s->timer = qemu_new_timer(rt_clock, buffered_rate_tick, s);
258 qemu_mod_timer(s->timer, qemu_get_clock(rt_clock) + 100);
260 return s->file;