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977184db DDAG |
1 | /* |
2 | * QEMU System Emulator | |
3 | * | |
4 | * Copyright (c) 2003-2008 Fabrice Bellard | |
826a7cd9 SB |
5 | * Copyright (c) 2014 IBM Corp. |
6 | * | |
7 | * Authors: | |
8 | * Stefan Berger <stefanb@linux.vnet.ibm.com> | |
977184db DDAG |
9 | * |
10 | * Permission is hereby granted, free of charge, to any person obtaining a copy | |
11 | * of this software and associated documentation files (the "Software"), to deal | |
12 | * in the Software without restriction, including without limitation the rights | |
13 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
14 | * copies of the Software, and to permit persons to whom the Software is | |
15 | * furnished to do so, subject to the following conditions: | |
16 | * | |
17 | * The above copyright notice and this permission notice shall be included in | |
18 | * all copies or substantial portions of the Software. | |
19 | * | |
20 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
21 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
22 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL | |
23 | * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
24 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
25 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN | |
26 | * THE SOFTWARE. | |
27 | */ | |
28 | #include "qemu-common.h" | |
d49b6836 | 29 | #include "qemu/error-report.h" |
977184db DDAG |
30 | #include "qemu/iov.h" |
31 | #include "qemu/sockets.h" | |
32 | #include "block/coroutine.h" | |
33 | #include "migration/migration.h" | |
34 | #include "migration/qemu-file.h" | |
35 | #include "migration/qemu-file-internal.h" | |
36 | #include "trace.h" | |
37 | ||
38 | #define QSB_CHUNK_SIZE (1 << 10) | |
39 | #define QSB_MAX_CHUNK_SIZE (16 * QSB_CHUNK_SIZE) | |
40 | ||
41 | /** | |
42 | * Create a QEMUSizedBuffer | |
43 | * This type of buffer uses scatter-gather lists internally and | |
44 | * can grow to any size. Any data array in the scatter-gather list | |
45 | * can hold different amount of bytes. | |
46 | * | |
47 | * @buffer: Optional buffer to copy into the QSB | |
48 | * @len: size of initial buffer; if @buffer is given, buffer must | |
49 | * hold at least len bytes | |
50 | * | |
51 | * Returns a pointer to a QEMUSizedBuffer or NULL on allocation failure | |
52 | */ | |
53 | QEMUSizedBuffer *qsb_create(const uint8_t *buffer, size_t len) | |
54 | { | |
55 | QEMUSizedBuffer *qsb; | |
56 | size_t alloc_len, num_chunks, i, to_copy; | |
57 | size_t chunk_size = (len > QSB_MAX_CHUNK_SIZE) | |
58 | ? QSB_MAX_CHUNK_SIZE | |
59 | : QSB_CHUNK_SIZE; | |
60 | ||
61 | num_chunks = DIV_ROUND_UP(len ? len : QSB_CHUNK_SIZE, chunk_size); | |
62 | alloc_len = num_chunks * chunk_size; | |
63 | ||
64 | qsb = g_try_new0(QEMUSizedBuffer, 1); | |
65 | if (!qsb) { | |
66 | return NULL; | |
67 | } | |
68 | ||
69 | qsb->iov = g_try_new0(struct iovec, num_chunks); | |
70 | if (!qsb->iov) { | |
71 | g_free(qsb); | |
72 | return NULL; | |
73 | } | |
74 | ||
75 | qsb->n_iov = num_chunks; | |
76 | ||
77 | for (i = 0; i < num_chunks; i++) { | |
78 | qsb->iov[i].iov_base = g_try_malloc0(chunk_size); | |
79 | if (!qsb->iov[i].iov_base) { | |
80 | /* qsb_free is safe since g_free can cope with NULL */ | |
81 | qsb_free(qsb); | |
82 | return NULL; | |
83 | } | |
84 | ||
85 | qsb->iov[i].iov_len = chunk_size; | |
86 | if (buffer) { | |
87 | to_copy = (len - qsb->used) > chunk_size | |
88 | ? chunk_size : (len - qsb->used); | |
89 | memcpy(qsb->iov[i].iov_base, &buffer[qsb->used], to_copy); | |
90 | qsb->used += to_copy; | |
91 | } | |
92 | } | |
93 | ||
94 | qsb->size = alloc_len; | |
95 | ||
96 | return qsb; | |
97 | } | |
98 | ||
99 | /** | |
100 | * Free the QEMUSizedBuffer | |
101 | * | |
102 | * @qsb: The QEMUSizedBuffer to free | |
103 | */ | |
104 | void qsb_free(QEMUSizedBuffer *qsb) | |
105 | { | |
106 | size_t i; | |
107 | ||
108 | if (!qsb) { | |
109 | return; | |
110 | } | |
111 | ||
112 | for (i = 0; i < qsb->n_iov; i++) { | |
113 | g_free(qsb->iov[i].iov_base); | |
114 | } | |
115 | g_free(qsb->iov); | |
116 | g_free(qsb); | |
117 | } | |
118 | ||
119 | /** | |
120 | * Get the number of used bytes in the QEMUSizedBuffer | |
121 | * | |
122 | * @qsb: A QEMUSizedBuffer | |
123 | * | |
124 | * Returns the number of bytes currently used in this buffer | |
125 | */ | |
126 | size_t qsb_get_length(const QEMUSizedBuffer *qsb) | |
127 | { | |
128 | return qsb->used; | |
129 | } | |
130 | ||
131 | /** | |
132 | * Set the length of the buffer; the primary usage of this | |
133 | * function is to truncate the number of used bytes in the buffer. | |
134 | * The size will not be extended beyond the current number of | |
135 | * allocated bytes in the QEMUSizedBuffer. | |
136 | * | |
137 | * @qsb: A QEMUSizedBuffer | |
138 | * @new_len: The new length of bytes in the buffer | |
139 | * | |
140 | * Returns the number of bytes the buffer was truncated or extended | |
141 | * to. | |
142 | */ | |
143 | size_t qsb_set_length(QEMUSizedBuffer *qsb, size_t new_len) | |
144 | { | |
145 | if (new_len <= qsb->size) { | |
146 | qsb->used = new_len; | |
147 | } else { | |
148 | qsb->used = qsb->size; | |
149 | } | |
150 | return qsb->used; | |
151 | } | |
152 | ||
153 | /** | |
154 | * Get the iovec that holds the data for a given position @pos. | |
155 | * | |
156 | * @qsb: A QEMUSizedBuffer | |
157 | * @pos: The index of a byte in the buffer | |
158 | * @d_off: Pointer to an offset that this function will indicate | |
159 | * at what position within the returned iovec the byte | |
160 | * is to be found | |
161 | * | |
162 | * Returns the index of the iovec that holds the byte at the given | |
163 | * index @pos in the byte stream; a negative number if the iovec | |
164 | * for the given position @pos does not exist. | |
165 | */ | |
166 | static ssize_t qsb_get_iovec(const QEMUSizedBuffer *qsb, | |
167 | off_t pos, off_t *d_off) | |
168 | { | |
169 | ssize_t i; | |
170 | off_t curr = 0; | |
171 | ||
172 | if (pos > qsb->used) { | |
173 | return -1; | |
174 | } | |
175 | ||
176 | for (i = 0; i < qsb->n_iov; i++) { | |
177 | if (curr + qsb->iov[i].iov_len > pos) { | |
178 | *d_off = pos - curr; | |
179 | return i; | |
180 | } | |
181 | curr += qsb->iov[i].iov_len; | |
182 | } | |
183 | return -1; | |
184 | } | |
185 | ||
186 | /* | |
187 | * Convert the QEMUSizedBuffer into a flat buffer. | |
188 | * | |
189 | * Note: If at all possible, try to avoid this function since it | |
190 | * may unnecessarily copy memory around. | |
191 | * | |
192 | * @qsb: pointer to QEMUSizedBuffer | |
193 | * @start: offset to start at | |
194 | * @count: number of bytes to copy | |
195 | * @buf: a pointer to a buffer to write into (at least @count bytes) | |
196 | * | |
197 | * Returns the number of bytes copied into the output buffer | |
198 | */ | |
199 | ssize_t qsb_get_buffer(const QEMUSizedBuffer *qsb, off_t start, | |
200 | size_t count, uint8_t *buffer) | |
201 | { | |
202 | const struct iovec *iov; | |
203 | size_t to_copy, all_copy; | |
204 | ssize_t index; | |
205 | off_t s_off; | |
206 | off_t d_off = 0; | |
207 | char *s; | |
208 | ||
209 | if (start > qsb->used) { | |
210 | return 0; | |
211 | } | |
212 | ||
213 | all_copy = qsb->used - start; | |
214 | if (all_copy > count) { | |
215 | all_copy = count; | |
216 | } else { | |
217 | count = all_copy; | |
218 | } | |
219 | ||
220 | index = qsb_get_iovec(qsb, start, &s_off); | |
221 | if (index < 0) { | |
222 | return 0; | |
223 | } | |
224 | ||
225 | while (all_copy > 0) { | |
226 | iov = &qsb->iov[index]; | |
227 | ||
228 | s = iov->iov_base; | |
229 | ||
230 | to_copy = iov->iov_len - s_off; | |
231 | if (to_copy > all_copy) { | |
232 | to_copy = all_copy; | |
233 | } | |
234 | memcpy(&buffer[d_off], &s[s_off], to_copy); | |
235 | ||
236 | d_off += to_copy; | |
237 | all_copy -= to_copy; | |
238 | ||
239 | s_off = 0; | |
240 | index++; | |
241 | } | |
242 | ||
243 | return count; | |
244 | } | |
245 | ||
246 | /** | |
247 | * Grow the QEMUSizedBuffer to the given size and allocate | |
248 | * memory for it. | |
249 | * | |
250 | * @qsb: A QEMUSizedBuffer | |
251 | * @new_size: The new size of the buffer | |
252 | * | |
253 | * Return: | |
254 | * a negative error code in case of memory allocation failure | |
255 | * or | |
256 | * the new size of the buffer. The returned size may be greater or equal | |
257 | * to @new_size. | |
258 | */ | |
259 | static ssize_t qsb_grow(QEMUSizedBuffer *qsb, size_t new_size) | |
260 | { | |
261 | size_t needed_chunks, i; | |
262 | ||
263 | if (qsb->size < new_size) { | |
264 | struct iovec *new_iov; | |
265 | size_t size_diff = new_size - qsb->size; | |
266 | size_t chunk_size = (size_diff > QSB_MAX_CHUNK_SIZE) | |
267 | ? QSB_MAX_CHUNK_SIZE : QSB_CHUNK_SIZE; | |
268 | ||
269 | needed_chunks = DIV_ROUND_UP(size_diff, chunk_size); | |
270 | ||
271 | new_iov = g_try_new(struct iovec, qsb->n_iov + needed_chunks); | |
272 | if (new_iov == NULL) { | |
273 | return -ENOMEM; | |
274 | } | |
275 | ||
276 | /* Allocate new chunks as needed into new_iov */ | |
277 | for (i = qsb->n_iov; i < qsb->n_iov + needed_chunks; i++) { | |
278 | new_iov[i].iov_base = g_try_malloc0(chunk_size); | |
279 | new_iov[i].iov_len = chunk_size; | |
280 | if (!new_iov[i].iov_base) { | |
281 | size_t j; | |
282 | ||
283 | /* Free previously allocated new chunks */ | |
284 | for (j = qsb->n_iov; j < i; j++) { | |
285 | g_free(new_iov[j].iov_base); | |
286 | } | |
287 | g_free(new_iov); | |
288 | ||
289 | return -ENOMEM; | |
290 | } | |
291 | } | |
292 | ||
293 | /* | |
294 | * Now we can't get any allocation errors, copy over to new iov | |
295 | * and switch. | |
296 | */ | |
297 | for (i = 0; i < qsb->n_iov; i++) { | |
298 | new_iov[i] = qsb->iov[i]; | |
299 | } | |
300 | ||
301 | qsb->n_iov += needed_chunks; | |
302 | g_free(qsb->iov); | |
303 | qsb->iov = new_iov; | |
304 | qsb->size += (needed_chunks * chunk_size); | |
305 | } | |
306 | ||
307 | return qsb->size; | |
308 | } | |
309 | ||
310 | /** | |
311 | * Write into the QEMUSizedBuffer at a given position and a given | |
312 | * number of bytes. This function will automatically grow the | |
313 | * QEMUSizedBuffer. | |
314 | * | |
315 | * @qsb: A QEMUSizedBuffer | |
316 | * @source: A byte array to copy data from | |
317 | * @pos: The position within the @qsb to write data to | |
318 | * @size: The number of bytes to copy into the @qsb | |
319 | * | |
320 | * Returns @size or a negative error code in case of memory allocation failure, | |
321 | * or with an invalid 'pos' | |
322 | */ | |
323 | ssize_t qsb_write_at(QEMUSizedBuffer *qsb, const uint8_t *source, | |
324 | off_t pos, size_t count) | |
325 | { | |
326 | ssize_t rc = qsb_grow(qsb, pos + count); | |
327 | size_t to_copy; | |
328 | size_t all_copy = count; | |
329 | const struct iovec *iov; | |
330 | ssize_t index; | |
331 | char *dest; | |
332 | off_t d_off, s_off = 0; | |
333 | ||
334 | if (rc < 0) { | |
335 | return rc; | |
336 | } | |
337 | ||
338 | if (pos + count > qsb->used) { | |
339 | qsb->used = pos + count; | |
340 | } | |
341 | ||
342 | index = qsb_get_iovec(qsb, pos, &d_off); | |
343 | if (index < 0) { | |
344 | return -EINVAL; | |
345 | } | |
346 | ||
347 | while (all_copy > 0) { | |
348 | iov = &qsb->iov[index]; | |
349 | ||
350 | dest = iov->iov_base; | |
351 | ||
352 | to_copy = iov->iov_len - d_off; | |
353 | if (to_copy > all_copy) { | |
354 | to_copy = all_copy; | |
355 | } | |
356 | ||
357 | memcpy(&dest[d_off], &source[s_off], to_copy); | |
358 | ||
359 | s_off += to_copy; | |
360 | all_copy -= to_copy; | |
361 | ||
362 | d_off = 0; | |
363 | index++; | |
364 | } | |
365 | ||
366 | return count; | |
367 | } | |
368 | ||
977184db DDAG |
369 | typedef struct QEMUBuffer { |
370 | QEMUSizedBuffer *qsb; | |
371 | QEMUFile *file; | |
f018d8cd | 372 | bool qsb_allocated; |
977184db DDAG |
373 | } QEMUBuffer; |
374 | ||
375 | static int buf_get_buffer(void *opaque, uint8_t *buf, int64_t pos, int size) | |
376 | { | |
377 | QEMUBuffer *s = opaque; | |
378 | ssize_t len = qsb_get_length(s->qsb) - pos; | |
379 | ||
380 | if (len <= 0) { | |
381 | return 0; | |
382 | } | |
383 | ||
384 | if (len > size) { | |
385 | len = size; | |
386 | } | |
387 | return qsb_get_buffer(s->qsb, pos, len, buf); | |
388 | } | |
389 | ||
390 | static int buf_put_buffer(void *opaque, const uint8_t *buf, | |
391 | int64_t pos, int size) | |
392 | { | |
393 | QEMUBuffer *s = opaque; | |
394 | ||
395 | return qsb_write_at(s->qsb, buf, pos, size); | |
396 | } | |
397 | ||
398 | static int buf_close(void *opaque) | |
399 | { | |
400 | QEMUBuffer *s = opaque; | |
401 | ||
f018d8cd YH |
402 | if (s->qsb_allocated) { |
403 | qsb_free(s->qsb); | |
404 | } | |
977184db DDAG |
405 | |
406 | g_free(s); | |
407 | ||
408 | return 0; | |
409 | } | |
410 | ||
411 | const QEMUSizedBuffer *qemu_buf_get(QEMUFile *f) | |
412 | { | |
413 | QEMUBuffer *p; | |
414 | ||
415 | qemu_fflush(f); | |
416 | ||
417 | p = f->opaque; | |
418 | ||
419 | return p->qsb; | |
420 | } | |
421 | ||
422 | static const QEMUFileOps buf_read_ops = { | |
423 | .get_buffer = buf_get_buffer, | |
424 | .close = buf_close, | |
425 | }; | |
426 | ||
427 | static const QEMUFileOps buf_write_ops = { | |
428 | .put_buffer = buf_put_buffer, | |
429 | .close = buf_close, | |
430 | }; | |
431 | ||
432 | QEMUFile *qemu_bufopen(const char *mode, QEMUSizedBuffer *input) | |
433 | { | |
434 | QEMUBuffer *s; | |
435 | ||
436 | if (mode == NULL || (mode[0] != 'r' && mode[0] != 'w') || | |
437 | mode[1] != '\0') { | |
438 | error_report("qemu_bufopen: Argument validity check failed"); | |
439 | return NULL; | |
440 | } | |
441 | ||
442 | s = g_malloc0(sizeof(QEMUBuffer)); | |
f018d8cd | 443 | s->qsb = input; |
977184db DDAG |
444 | |
445 | if (s->qsb == NULL) { | |
446 | s->qsb = qsb_create(NULL, 0); | |
f018d8cd | 447 | s->qsb_allocated = true; |
977184db DDAG |
448 | } |
449 | if (!s->qsb) { | |
450 | g_free(s); | |
451 | error_report("qemu_bufopen: qsb_create failed"); | |
452 | return NULL; | |
453 | } | |
454 | ||
455 | ||
456 | if (mode[0] == 'r') { | |
457 | s->file = qemu_fopen_ops(s, &buf_read_ops); | |
458 | } else { | |
459 | s->file = qemu_fopen_ops(s, &buf_write_ops); | |
460 | } | |
461 | return s->file; | |
462 | } |