1/*
2 * Copyright © 2014 Intel Corporation
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
21 * IN THE SOFTWARE.
22 */
23
24#include <string.h>
25
26#include "main/macros.h"
27#include "blob.h"
28
29#ifdef HAVE_VALGRIND
30#include <valgrind.h>
31#include <memcheck.h>
32#define VG(x) x
33#else
34#define VG(x)
35#endif
36
37#define BLOB_INITIAL_SIZE 4096
38
39/* Ensure that \blob will be able to fit an additional object of size
40 * \additional.  The growing (if any) will occur by doubling the existing
41 * allocation.
42 */
43static bool
44grow_to_fit(struct blob *blob, size_t additional)
45{
46   size_t to_allocate;
47   uint8_t *new_data;
48
49   if (blob->out_of_memory)
50      return false;
51
52   if (blob->size + additional <= blob->allocated)
53      return true;
54
55   if (blob->fixed_allocation) {
56      blob->out_of_memory = true;
57      return false;
58   }
59
60   if (blob->allocated == 0)
61      to_allocate = BLOB_INITIAL_SIZE;
62   else
63      to_allocate = blob->allocated * 2;
64
65   to_allocate = MAX2(to_allocate, blob->allocated + additional);
66
67   new_data = realloc(blob->data, to_allocate);
68   if (new_data == NULL) {
69      blob->out_of_memory = true;
70      return false;
71   }
72
73   blob->data = new_data;
74   blob->allocated = to_allocate;
75
76   return true;
77}
78
79/* Align the blob->size so that reading or writing a value at (blob->data +
80 * blob->size) will result in an access aligned to a granularity of \alignment
81 * bytes.
82 *
83 * \return True unless allocation fails
84 */
85static bool
86align_blob(struct blob *blob, size_t alignment)
87{
88   const size_t new_size = ALIGN(blob->size, alignment);
89
90   if (blob->size < new_size) {
91      if (!grow_to_fit(blob, new_size - blob->size))
92         return false;
93
94      if (blob->data)
95         memset(blob->data + blob->size, 0, new_size - blob->size);
96      blob->size = new_size;
97   }
98
99   return true;
100}
101
102static void
103align_blob_reader(struct blob_reader *blob, size_t alignment)
104{
105   blob->current = blob->data + ALIGN(blob->current - blob->data, alignment);
106}
107
108void
109blob_init(struct blob *blob)
110{
111   blob->data = NULL;
112   blob->allocated = 0;
113   blob->size = 0;
114   blob->fixed_allocation = false;
115   blob->out_of_memory = false;
116}
117
118void
119blob_init_fixed(struct blob *blob, void *data, size_t size)
120{
121   blob->data = data;
122   blob->allocated = size;
123   blob->size = 0;
124   blob->fixed_allocation = true;
125   blob->out_of_memory = false;
126}
127
128bool
129blob_overwrite_bytes(struct blob *blob,
130                     size_t offset,
131                     const void *bytes,
132                     size_t to_write)
133{
134   /* Detect an attempt to overwrite data out of bounds. */
135   if (offset + to_write < offset || blob->size < offset + to_write)
136      return false;
137
138   VG(VALGRIND_CHECK_MEM_IS_DEFINED(bytes, to_write));
139
140   if (blob->data)
141      memcpy(blob->data + offset, bytes, to_write);
142
143   return true;
144}
145
146bool
147blob_write_bytes(struct blob *blob, const void *bytes, size_t to_write)
148{
149   if (! grow_to_fit(blob, to_write))
150       return false;
151
152   VG(VALGRIND_CHECK_MEM_IS_DEFINED(bytes, to_write));
153
154   if (blob->data)
155      memcpy(blob->data + blob->size, bytes, to_write);
156   blob->size += to_write;
157
158   return true;
159}
160
161intptr_t
162blob_reserve_bytes(struct blob *blob, size_t to_write)
163{
164   intptr_t ret;
165
166   if (! grow_to_fit (blob, to_write))
167      return -1;
168
169   ret = blob->size;
170   blob->size += to_write;
171
172   return ret;
173}
174
175intptr_t
176blob_reserve_uint32(struct blob *blob)
177{
178   align_blob(blob, sizeof(uint32_t));
179   return blob_reserve_bytes(blob, sizeof(uint32_t));
180}
181
182intptr_t
183blob_reserve_intptr(struct blob *blob)
184{
185   align_blob(blob, sizeof(intptr_t));
186   return blob_reserve_bytes(blob, sizeof(intptr_t));
187}
188
189bool
190blob_write_uint32(struct blob *blob, uint32_t value)
191{
192   align_blob(blob, sizeof(value));
193
194   return blob_write_bytes(blob, &value, sizeof(value));
195}
196
197#define ASSERT_ALIGNED(_offset, _align) \
198   assert(ALIGN((_offset), (_align)) == (_offset))
199
200bool
201blob_overwrite_uint32 (struct blob *blob,
202                       size_t offset,
203                       uint32_t value)
204{
205   ASSERT_ALIGNED(offset, sizeof(value));
206   return blob_overwrite_bytes(blob, offset, &value, sizeof(value));
207}
208
209bool
210blob_write_uint64(struct blob *blob, uint64_t value)
211{
212   align_blob(blob, sizeof(value));
213
214   return blob_write_bytes(blob, &value, sizeof(value));
215}
216
217bool
218blob_write_intptr(struct blob *blob, intptr_t value)
219{
220   align_blob(blob, sizeof(value));
221
222   return blob_write_bytes(blob, &value, sizeof(value));
223}
224
225bool
226blob_overwrite_intptr (struct blob *blob,
227                       size_t offset,
228                       intptr_t value)
229{
230   ASSERT_ALIGNED(offset, sizeof(value));
231   return blob_overwrite_bytes(blob, offset, &value, sizeof(value));
232}
233
234bool
235blob_write_string(struct blob *blob, const char *str)
236{
237   return blob_write_bytes(blob, str, strlen(str) + 1);
238}
239
240void
241blob_reader_init(struct blob_reader *blob, const void *data, size_t size)
242{
243   blob->data = data;
244   blob->end = blob->data + size;
245   blob->current = data;
246   blob->overrun = false;
247}
248
249/* Check that an object of size \size can be read from this blob.
250 *
251 * If not, set blob->overrun to indicate that we attempted to read too far.
252 */
253static bool
254ensure_can_read(struct blob_reader *blob, size_t size)
255{
256   if (blob->overrun)
257      return false;
258
259   if (blob->current <= blob->end && blob->end - blob->current >= size)
260      return true;
261
262   blob->overrun = true;
263
264   return false;
265}
266
267const void *
268blob_read_bytes(struct blob_reader *blob, size_t size)
269{
270   const void *ret;
271
272   if (! ensure_can_read (blob, size))
273      return NULL;
274
275   ret = blob->current;
276
277   blob->current += size;
278
279   return ret;
280}
281
282void
283blob_copy_bytes(struct blob_reader *blob, void *dest, size_t size)
284{
285   const void *bytes;
286
287   bytes = blob_read_bytes(blob, size);
288   if (bytes == NULL)
289      return;
290
291   memcpy(dest, bytes, size);
292}
293
294void
295blob_skip_bytes(struct blob_reader *blob, size_t size)
296{
297   if (ensure_can_read (blob, size))
298      blob->current += size;
299}
300
301/* These next three read functions have identical form. If we add any beyond
302 * these first three we should probably switch to generating these with a
303 * preprocessor macro.
304*/
305uint32_t
306blob_read_uint32(struct blob_reader *blob)
307{
308   uint32_t ret;
309   int size = sizeof(ret);
310
311   align_blob_reader(blob, size);
312
313   if (! ensure_can_read(blob, size))
314      return 0;
315
316   ret = *((uint32_t*) blob->current);
317
318   blob->current += size;
319
320   return ret;
321}
322
323uint64_t
324blob_read_uint64(struct blob_reader *blob)
325{
326   uint64_t ret;
327   int size = sizeof(ret);
328
329   align_blob_reader(blob, size);
330
331   if (! ensure_can_read(blob, size))
332      return 0;
333
334   ret = *((uint64_t*) blob->current);
335
336   blob->current += size;
337
338   return ret;
339}
340
341intptr_t
342blob_read_intptr(struct blob_reader *blob)
343{
344   intptr_t ret;
345   int size = sizeof(ret);
346
347   align_blob_reader(blob, size);
348
349   if (! ensure_can_read(blob, size))
350      return 0;
351
352   ret = *((intptr_t *) blob->current);
353
354   blob->current += size;
355
356   return ret;
357}
358
359char *
360blob_read_string(struct blob_reader *blob)
361{
362   int size;
363   char *ret;
364   uint8_t *nul;
365
366   /* If we're already at the end, then this is an overrun. */
367   if (blob->current >= blob->end) {
368      blob->overrun = true;
369      return NULL;
370   }
371
372   /* Similarly, if there is no zero byte in the data remaining in this blob,
373    * we also consider that an overrun.
374    */
375   nul = memchr(blob->current, 0, blob->end - blob->current);
376
377   if (nul == NULL) {
378      blob->overrun = true;
379      return NULL;
380   }
381
382   size = nul - blob->current + 1;
383
384   assert(ensure_can_read(blob, size));
385
386   ret = (char *) blob->current;
387
388   blob->current += size;
389
390   return ret;
391}
392