2 * Copyright (c) 2018 Stefan Sperling <stsp@openbsd.org>
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.
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.
17 #include <sys/queue.h>
28 #include "got_error.h"
29 #include "got_repository.h"
30 #include "got_object.h"
33 #include "got_lib_delta.h"
34 #include "got_lib_inflate.h"
35 #include "got_lib_object.h"
38 #define MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
42 got_delta_open(off_t offset, size_t tslen, int type, size_t size,
45 struct got_delta *delta;
47 delta = malloc(sizeof(*delta));
52 delta->offset = offset;
55 delta->data_offset = data_offset;
59 const struct got_error *
60 got_delta_chain_get_base_type(int *type, struct got_delta_chain *deltas)
62 struct got_delta *delta;
64 /* The first delta in the chain should represent the base object. */
65 delta = SIMPLEQ_FIRST(&deltas->entries);
66 if (delta->type == GOT_OBJ_TYPE_COMMIT ||
67 delta->type == GOT_OBJ_TYPE_TREE ||
68 delta->type == GOT_OBJ_TYPE_BLOB ||
69 delta->type == GOT_OBJ_TYPE_TAG) {
74 return got_error(GOT_ERR_BAD_DELTA_CHAIN);
77 /* Fetch another (required) byte from the delta stream. */
78 static const struct got_error *
79 next_delta_byte(const uint8_t **p, size_t *remain)
82 return got_error(GOT_ERR_BAD_DELTA);
87 static const struct got_error *
88 parse_size(uint64_t *size, const uint8_t **p, size_t *remain)
90 const struct got_error *err = NULL;
95 /* We do not support size values which don't fit in 64 bit. */
97 return got_error(GOT_ERR_NO_SPACE);
100 *size = ((**p) & GOT_DELTA_SIZE_VAL_MASK);
102 size_t shift = GOT_DELTA_SIZE_SHIFT * i;
103 *size |= (((**p) & GOT_DELTA_SIZE_VAL_MASK) << shift);
106 if (((**p) & GOT_DELTA_SIZE_MORE) == 0)
109 err = next_delta_byte(p, remain);
110 } while (err == NULL);
115 static const struct got_error *
116 parse_opcode(off_t *offset, size_t *len, const uint8_t **p, size_t *remain)
118 const struct got_error *err = NULL;
121 uint8_t opcode = **p;
123 if (opcode & GOT_DELTA_COPY_OFF1) {
124 err = next_delta_byte(p, remain);
129 if (opcode & GOT_DELTA_COPY_OFF2) {
130 err = next_delta_byte(p, remain);
133 o |= ((off_t)(**p)) << 8;
135 if (opcode & GOT_DELTA_COPY_OFF3) {
136 err = next_delta_byte(p, remain);
139 o |= ((off_t)(**p)) << 16;
141 if (opcode & GOT_DELTA_COPY_OFF4) {
142 err = next_delta_byte(p, remain);
145 o |= ((off_t)(**p)) << 24;
148 if (opcode & GOT_DELTA_COPY_LEN1) {
149 err = next_delta_byte(p, remain);
154 if (opcode & GOT_DELTA_COPY_LEN2) {
155 err = next_delta_byte(p, remain);
158 l |= ((off_t)(**p)) << 8;
160 if (opcode & GOT_DELTA_COPY_LEN3) {
161 err = next_delta_byte(p, remain);
164 l |= ((off_t)(**p)) << 16;
168 o = GOT_DELTA_COPY_DEFAULT_OFF;
170 l = GOT_DELTA_COPY_DEFAULT_LEN;
177 static const struct got_error *
178 copy_from_base(FILE *base_file, off_t offset, size_t size, FILE *outfile)
180 if (fseeko(base_file, offset, SEEK_SET) != 0)
181 return got_error_from_errno("fseeko");
185 size_t len = MIN(size, sizeof(data));
188 n = fread(data, len, 1, base_file);
190 return got_ferror(base_file, GOT_ERR_IO);
192 n = fwrite(data, len, 1, outfile);
194 return got_ferror(outfile, GOT_ERR_IO);
202 static const struct got_error *
203 copy_from_delta(const uint8_t **p, size_t *remain, size_t len, FILE *outfile)
208 return got_error(GOT_ERR_BAD_DELTA);
210 n = fwrite(*p, len, 1, outfile);
212 return got_ferror(outfile, GOT_ERR_IO);
219 static const struct got_error *
220 parse_delta_sizes(uint64_t *base_size, uint64_t *result_size,
221 const uint8_t **p, size_t *remain)
223 const struct got_error *err;
225 /* Read the two size fields at the beginning of the stream. */
226 err = parse_size(base_size, p, remain);
229 err = next_delta_byte(p, remain);
232 err = parse_size(result_size, p, remain);
239 const struct got_error *
240 got_delta_get_sizes(uint64_t *base_size, uint64_t *result_size,
241 const uint8_t *delta_buf, size_t delta_len)
246 if (delta_len < GOT_DELTA_STREAM_LENGTH_MIN)
247 return got_error(GOT_ERR_BAD_DELTA);
251 return parse_delta_sizes(base_size, result_size, &p, &remain);
254 const struct got_error *
255 got_delta_apply_in_mem(uint8_t *base_buf, size_t base_bufsz,
256 const uint8_t *delta_buf, size_t delta_len, uint8_t *outbuf,
257 size_t *outsize, size_t maxoutsize)
259 const struct got_error *err = NULL;
260 uint64_t base_size, result_size;
266 if (delta_len < GOT_DELTA_STREAM_LENGTH_MIN)
267 return got_error(GOT_ERR_BAD_DELTA);
271 err = parse_delta_sizes(&base_size, &result_size, &p, &remain);
275 /* Decode and execute copy instructions from the delta stream. */
276 err = next_delta_byte(&p, &remain);
277 while (err == NULL && remain > 0) {
278 if (*p & GOT_DELTA_BASE_COPY) {
281 err = parse_opcode(&offset, &len, &p, &remain);
284 if (SIZE_MAX - offset < len || offset + len < 0 ||
285 base_bufsz < offset + len ||
286 *outsize + len > maxoutsize)
287 return got_error(GOT_ERR_BAD_DELTA);
288 memcpy(outbuf + *outsize, base_buf + offset, len);
297 size_t len = (size_t)*p;
299 err = got_error(GOT_ERR_BAD_DELTA);
302 err = next_delta_byte(&p, &remain);
305 if (remain < len || SIZE_MAX - *outsize < len ||
306 *outsize + len > maxoutsize)
307 return got_error(GOT_ERR_BAD_DELTA);
308 memcpy(outbuf + *outsize, p, len);
315 if (*outsize != result_size)
316 err = got_error(GOT_ERR_BAD_DELTA);
320 const struct got_error *
321 got_delta_apply(FILE *base_file, const uint8_t *delta_buf,
322 size_t delta_len, FILE *outfile, size_t *outsize)
324 const struct got_error *err = NULL;
325 uint64_t base_size, result_size;
328 FILE *memstream = NULL;
329 char *memstream_buf = NULL;
330 size_t memstream_size = 0;
334 if (delta_len < GOT_DELTA_STREAM_LENGTH_MIN)
335 return got_error(GOT_ERR_BAD_DELTA);
339 err = parse_delta_sizes(&base_size, &result_size, &p, &remain);
343 if (result_size < GOT_DELTA_RESULT_SIZE_CACHED_MAX)
344 memstream = open_memstream(&memstream_buf, &memstream_size);
346 /* Decode and execute copy instructions from the delta stream. */
347 err = next_delta_byte(&p, &remain);
348 while (err == NULL && remain > 0) {
349 if (*p & GOT_DELTA_BASE_COPY) {
352 err = parse_opcode(&offset, &len, &p, &remain);
355 err = copy_from_base(base_file, offset, len,
356 memstream ? memstream : outfile);
365 size_t len = (size_t)*p;
367 err = got_error(GOT_ERR_BAD_DELTA);
370 err = next_delta_byte(&p, &remain);
373 err = copy_from_delta(&p, &remain, len,
374 memstream ? memstream : outfile);
380 if (*outsize != result_size)
381 err = got_error(GOT_ERR_BAD_DELTA);
383 if (memstream != NULL) {
384 if (fclose(memstream) != 0)
385 err = got_error_from_errno("fclose");
388 n = fwrite(memstream_buf, 1, memstream_size, outfile);
389 if (n != memstream_size)
390 err = got_ferror(outfile, GOT_ERR_IO);