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Date:: Thu Nov 28 02:32:58 2019 UTC
Message:: convert tree entries from SIMPLEQ to an array
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1 /*
2  * Copyright (c) 2018 Stefan Sperling <stsp@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include <sys/queue.h>
18 
19 #include <stdio.h>
20 #include <stdlib.h>
21 #include <stdint.h>
22 #include <string.h>
23 #include <limits.h>
24 #include <zlib.h>
25 #include <sha1.h>
26 #include <time.h>
27 #include <zlib.h>
28 
29 #include "got_error.h"
30 #include "got_repository.h"
31 #include "got_object.h"
32 #include "got_path.h"
33 
34 #include "got_lib_delta.h"
35 #include "got_lib_inflate.h"
36 #include "got_lib_object.h"
37 
38 #ifndef MIN
39 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
40 #endif
41 
42 struct got_delta *
43 got_delta_open(off_t offset, size_t tslen, int type, size_t size,
44     off_t data_offset)
45 {
46 	struct got_delta *delta;
47 
48 	delta = malloc(sizeof(*delta));
49 	if (delta == NULL)
50 		return NULL;
51 
52 	delta->type = type;
53 	delta->offset = offset;
54 	delta->tslen = tslen;
55 	delta->size = size;
56 	delta->data_offset = data_offset;
57 	return delta;
58 }
59 
60 const struct got_error *
61 got_delta_chain_get_base_type(int *type, struct got_delta_chain *deltas)
62 {
63 	struct got_delta *delta;
64 
65 	/* The first delta in the chain should represent the base object. */
66 	delta = SIMPLEQ_FIRST(&deltas->entries);
67 	if (delta->type == GOT_OBJ_TYPE_COMMIT ||
68 	    delta->type == GOT_OBJ_TYPE_TREE ||
69 	    delta->type == GOT_OBJ_TYPE_BLOB ||
70 	    delta->type == GOT_OBJ_TYPE_TAG) {
71 		*type = delta->type;
72 		return NULL;
73 	}
74 
75 	return got_error(GOT_ERR_BAD_DELTA_CHAIN);
76 }
77 
78 /* Fetch another (required) byte from the delta stream. */
79 static const struct got_error *
80 next_delta_byte(const uint8_t **p, size_t *remain)
81 {
82 	if (--(*remain) == 0)
83 		return got_error(GOT_ERR_BAD_DELTA);
84 	(*p)++;
85 	return NULL;
86 }
87 
88 static const struct got_error *
89 parse_size(uint64_t *size, const uint8_t **p, size_t *remain)
90 {
91 	const struct got_error *err = NULL;
92 	int i = 0;
93 
94 	*size = 0;
95 	do {
96 		/* We do not support size values which don't fit in 64 bit. */
97 		if (i > 9)
98 			return got_error(GOT_ERR_NO_SPACE);
99 
100 		if (i == 0)
101 			*size = ((**p) & GOT_DELTA_SIZE_VAL_MASK);
102 		else {
103 			size_t shift = GOT_DELTA_SIZE_SHIFT * i;
104 			*size |= (((**p) & GOT_DELTA_SIZE_VAL_MASK) << shift);
105 		}
106 
107 		if (((**p) & GOT_DELTA_SIZE_MORE) == 0)
108 			break;
109 		i++;
110 		err = next_delta_byte(p, remain);
111 	} while (err == NULL);
112 
113 	return err;
114 }
115 
116 static const struct got_error *
117 parse_opcode(off_t *offset, size_t *len, const uint8_t **p, size_t *remain)
118 {
119 	const struct got_error *err = NULL;
120 	off_t o = 0;
121 	size_t l = 0;
122 	uint8_t opcode = **p;
123 
124 	if (opcode & GOT_DELTA_COPY_OFF1) {
125 		err = next_delta_byte(p, remain);
126 		if (err)
127 			return err;
128 		o = (off_t)(**p);
129 	}
130 	if (opcode & GOT_DELTA_COPY_OFF2) {
131 		err = next_delta_byte(p, remain);
132 		if (err)
133 			return err;
134 		o |= ((off_t)(**p)) << 8;
135 	}
136 	if (opcode & GOT_DELTA_COPY_OFF3) {
137 		err = next_delta_byte(p, remain);
138 		if (err)
139 			return err;
140 		o |= ((off_t)(**p)) << 16;
141 	}
142 	if (opcode & GOT_DELTA_COPY_OFF4) {
143 		err = next_delta_byte(p, remain);
144 		if (err)
145 			return err;
146 		o |= ((off_t)(**p)) << 24;
147 	}
148 
149 	if (opcode & GOT_DELTA_COPY_LEN1) {
150 		err = next_delta_byte(p, remain);
151 		if (err)
152 			return err;
153 		l = (off_t)(**p);
154 	}
155 	if (opcode & GOT_DELTA_COPY_LEN2) {
156 		err = next_delta_byte(p, remain);
157 		if (err)
158 			return err;
159 		l |= ((off_t)(**p)) << 8;
160 	}
161 	if (opcode & GOT_DELTA_COPY_LEN3) {
162 		err = next_delta_byte(p, remain);
163 		if (err)
164 			return err;
165 		l |= ((off_t)(**p)) << 16;
166 	}
167 
168 	if (o == 0)
169 		o = GOT_DELTA_COPY_DEFAULT_OFF;
170 	if (l == 0)
171 		l = GOT_DELTA_COPY_DEFAULT_LEN;
172 
173 	*offset = o;
174 	*len = l;
175 	return NULL;
176 }
177 
178 static const struct got_error *
179 copy_from_base(FILE *base_file, off_t offset, size_t size, FILE *outfile)
180 {
181 	if (fseeko(base_file, offset, SEEK_SET) != 0)
182 		return got_error_from_errno("fseeko");
183 
184 	while (size > 0) {
185 		uint8_t data[2048];
186 		size_t len = MIN(size, sizeof(data));
187 		size_t n;
188 
189 		n = fread(data, len, 1, base_file);
190 		if (n != 1)
191 			return got_ferror(base_file, GOT_ERR_IO);
192 
193 		n = fwrite(data, len, 1, outfile);
194 		if (n != 1)
195 			return got_ferror(outfile, GOT_ERR_IO);
196 
197 		size -= len;
198 	}
199 
200 	return NULL;
201 }
202 
203 static const struct got_error *
204 copy_from_delta(const uint8_t **p, size_t *remain, size_t len, FILE *outfile)
205 {
206 	size_t n;
207 
208 	if (*remain < len)
209 		return got_error(GOT_ERR_BAD_DELTA);
210 
211 	n = fwrite(*p, len, 1, outfile);
212 	if (n != 1)
213 		return got_ferror(outfile, GOT_ERR_IO);
214 
215 	*p += len;
216 	*remain -= len;
217 	return NULL;
218 }
219 
220 static const struct got_error *
221 parse_delta_sizes(uint64_t *base_size, uint64_t *result_size,
222     const uint8_t **p, size_t *remain)
223 {
224 	const struct got_error *err;
225 
226 	/* Read the two size fields at the beginning of the stream. */
227 	err = parse_size(base_size, p, remain);
228 	if (err)
229 		return err;
230 	err = next_delta_byte(p, remain);
231 	if (err)
232 		return err;
233 	err = parse_size(result_size, p, remain);
234 	if (err)
235 		return err;
236 
237 	return NULL;
238 }
239 
240 const struct got_error *
241 got_delta_get_sizes(uint64_t *base_size, uint64_t *result_size,
242     const uint8_t *delta_buf, size_t delta_len)
243 {
244 	size_t remain;
245 	const uint8_t *p;
246 
247 	if (delta_len < GOT_DELTA_STREAM_LENGTH_MIN)
248 		return got_error(GOT_ERR_BAD_DELTA);
249 
250 	p = delta_buf;
251 	remain = delta_len;
252 	return parse_delta_sizes(base_size, result_size, &p, &remain);
253 }
254 
255 const struct got_error *
256 got_delta_apply_in_mem(uint8_t *base_buf, size_t base_bufsz,
257     const uint8_t *delta_buf, size_t delta_len, uint8_t *outbuf,
258     size_t *outsize, size_t maxoutsize)
259 {
260 	const struct got_error *err = NULL;
261 	uint64_t base_size, result_size;
262 	size_t remain;
263 	const uint8_t *p;
264 
265 	*outsize= 0;
266 
267 	if (delta_len < GOT_DELTA_STREAM_LENGTH_MIN)
268 		return got_error(GOT_ERR_BAD_DELTA);
269 
270 	p = delta_buf;
271 	remain = delta_len;
272 	err = parse_delta_sizes(&base_size, &result_size, &p, &remain);
273 	if (err)
274 		return err;
275 
276 	/* Decode and execute copy instructions from the delta stream. */
277 	err = next_delta_byte(&p, &remain);
278 	while (err == NULL && remain > 0) {
279 		if (*p & GOT_DELTA_BASE_COPY) {
280 			off_t offset = 0;
281 			size_t len = 0;
282 			err = parse_opcode(&offset, &len, &p, &remain);
283 			if (err)
284 				break;
285 			if (SIZE_MAX - offset < len || offset + len < 0 ||
286 			    base_bufsz < offset + len ||
287 			    *outsize + len > maxoutsize)
288 				return got_error(GOT_ERR_BAD_DELTA);
289 			memcpy(outbuf + *outsize, base_buf + offset, len);
290 			if (err == NULL) {
291 				*outsize += len;
292 				if (remain > 0) {
293 					p++;
294 					remain--;
295 				}
296 			}
297 		} else {
298 			size_t len = (size_t)*p;
299 			if (len == 0) {
300 				err = got_error(GOT_ERR_BAD_DELTA);
301 				break;
302 			}
303 			err = next_delta_byte(&p, &remain);
304 			if (err)
305 				break;
306 			if (remain < len || SIZE_MAX - *outsize < len ||
307 			    *outsize + len > maxoutsize)
308 				return got_error(GOT_ERR_BAD_DELTA);
309 			memcpy(outbuf + *outsize, p, len);
310 			p += len;
311 			remain -= len;
312 			*outsize += len;
313 		}
314 	}
315 
316 	if (*outsize != result_size)
317 		err = got_error(GOT_ERR_BAD_DELTA);
318 	return err;
319 }
320 
321 const struct got_error *
322 got_delta_apply(FILE *base_file, const uint8_t *delta_buf,
323     size_t delta_len, FILE *outfile, size_t *outsize)
324 {
325 	const struct got_error *err = NULL;
326 	uint64_t base_size, result_size;
327 	size_t remain = 0;
328 	const uint8_t *p;
329 	FILE *memstream = NULL;
330 	char *memstream_buf = NULL;
331 	size_t memstream_size = 0;
332 
333 	*outsize = 0;
334 
335 	if (delta_len < GOT_DELTA_STREAM_LENGTH_MIN)
336 		return got_error(GOT_ERR_BAD_DELTA);
337 
338 	p = delta_buf;
339 	remain = delta_len;
340 	err = parse_delta_sizes(&base_size, &result_size, &p, &remain);
341 	if (err)
342 		return err;
343 
344 	if (result_size < GOT_DELTA_RESULT_SIZE_CACHED_MAX)
345 		memstream = open_memstream(&memstream_buf, &memstream_size);
346 
347 	/* Decode and execute copy instructions from the delta stream. */
348 	err = next_delta_byte(&p, &remain);
349 	while (err == NULL && remain > 0) {
350 		if (*p & GOT_DELTA_BASE_COPY) {
351 			off_t offset = 0;
352 			size_t len = 0;
353 			err = parse_opcode(&offset, &len, &p, &remain);
354 			if (err)
355 				break;
356 			err = copy_from_base(base_file, offset, len,
357 			    memstream ? memstream : outfile);
358 			if (err == NULL) {
359 				*outsize += len;
360 				if (remain > 0) {
361 					p++;
362 					remain--;
363 				}
364 			}
365 		} else {
366 			size_t len = (size_t)*p;
367 			if (len == 0) {
368 				err = got_error(GOT_ERR_BAD_DELTA);
369 				break;
370 			}
371 			err = next_delta_byte(&p, &remain);
372 			if (err)
373 				break;
374 			err = copy_from_delta(&p, &remain, len,
375 			    memstream ? memstream : outfile);
376 			if (err == NULL)
377 				*outsize += len;
378 		}
379 	}
380 
381 	if (*outsize != result_size)
382 		err = got_error(GOT_ERR_BAD_DELTA);
383 
384 	if (memstream != NULL) {
385 		if (fclose(memstream) != 0)
386 			err = got_error_from_errno("fclose");
387 		if (err == NULL) {
388 			size_t n;
389 			n = fwrite(memstream_buf, 1, memstream_size, outfile);
390 			if (n != memstream_size)
391 				err = got_ferror(outfile, GOT_ERR_IO);
392 		}
393 		free(memstream_buf);
394 	}
395 	if (err == NULL)
396 		rewind(outfile);
397 	return err;
398 }