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.
27 #include "got_error.h"
28 #include "got_repository.h"
29 #include "got_object.h"
32 #include "got_lib_delta.h"
33 #include "got_lib_inflate.h"
34 #include "got_lib_object.h"
37 #define MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
41 got_delta_open(off_t offset, size_t tslen, int type, size_t size,
44 struct got_delta *delta;
46 delta = malloc(sizeof(*delta));
51 delta->offset = offset;
54 delta->data_offset = data_offset;
58 const struct got_error *
59 got_delta_chain_get_base_type(int *type, struct got_delta_chain *deltas)
61 struct got_delta *delta;
63 /* The first delta in the chain should represent the base object. */
64 delta = STAILQ_FIRST(&deltas->entries);
65 if (delta->type == GOT_OBJ_TYPE_COMMIT ||
66 delta->type == GOT_OBJ_TYPE_TREE ||
67 delta->type == GOT_OBJ_TYPE_BLOB ||
68 delta->type == GOT_OBJ_TYPE_TAG) {
73 return got_error(GOT_ERR_BAD_DELTA_CHAIN);
76 /* Fetch another (required) byte from the delta stream. */
77 static const struct got_error *
78 next_delta_byte(const uint8_t **p, size_t *remain)
81 return got_error_msg(GOT_ERR_BAD_DELTA,
82 "delta data truncated");
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_msg(GOT_ERR_BAD_DELTA,
209 "copy from beyond end of delta data");
211 n = fwrite(*p, len, 1, outfile);
213 return got_ferror(outfile, GOT_ERR_IO);
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)
224 const struct got_error *err;
226 /* Read the two size fields at the beginning of the stream. */
227 err = parse_size(base_size, p, remain);
230 err = next_delta_byte(p, remain);
233 err = parse_size(result_size, p, remain);
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)
247 if (delta_len < GOT_DELTA_STREAM_LENGTH_MIN)
248 return got_error_msg(GOT_ERR_BAD_DELTA, "delta too small");
252 return parse_delta_sizes(base_size, result_size, &p, &remain);
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)
260 const struct got_error *err = NULL;
261 uint64_t base_size, result_size;
267 if (delta_len < GOT_DELTA_STREAM_LENGTH_MIN)
268 return got_error_msg(GOT_ERR_BAD_DELTA, "delta too small");
272 err = parse_delta_sizes(&base_size, &result_size, &p, &remain);
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) {
282 err = parse_opcode(&offset, &len, &p, &remain);
285 if (SIZE_MAX - offset < len || offset + len < 0 ||
286 base_bufsz < offset + len ||
287 *outsize + len > maxoutsize)
288 return got_error_msg(GOT_ERR_BAD_DELTA,
289 "bad delta copy length");
290 memcpy(outbuf + *outsize, base_buf + offset, len);
299 size_t len = (size_t)*p;
301 err = got_error_msg(GOT_ERR_BAD_DELTA,
302 "zero length delta");
305 err = next_delta_byte(&p, &remain);
308 if (remain < len || SIZE_MAX - *outsize < len ||
309 *outsize + len > maxoutsize)
310 return got_error_msg(GOT_ERR_BAD_DELTA,
311 "bad delta copy length");
312 memcpy(outbuf + *outsize, p, len);
319 if (*outsize != result_size)
320 err = got_error_msg(GOT_ERR_BAD_DELTA,
321 "delta application result size mismatch");
325 const struct got_error *
326 got_delta_apply(FILE *base_file, const uint8_t *delta_buf,
327 size_t delta_len, FILE *outfile, size_t *outsize)
329 const struct got_error *err = NULL;
330 uint64_t base_size, result_size;
333 FILE *memstream = NULL;
334 char *memstream_buf = NULL;
335 size_t memstream_size = 0;
339 if (delta_len < GOT_DELTA_STREAM_LENGTH_MIN)
340 return got_error_msg(GOT_ERR_BAD_DELTA, "delta too small");
344 err = parse_delta_sizes(&base_size, &result_size, &p, &remain);
348 if (result_size < GOT_DELTA_RESULT_SIZE_CACHED_MAX)
349 memstream = open_memstream(&memstream_buf, &memstream_size);
351 /* Decode and execute copy instructions from the delta stream. */
352 err = next_delta_byte(&p, &remain);
353 while (err == NULL && remain > 0) {
354 if (*p & GOT_DELTA_BASE_COPY) {
357 err = parse_opcode(&offset, &len, &p, &remain);
360 err = copy_from_base(base_file, offset, len,
361 memstream ? memstream : outfile);
370 size_t len = (size_t)*p;
372 err = got_error_msg(GOT_ERR_BAD_DELTA,
373 "zero length delta");
376 err = next_delta_byte(&p, &remain);
379 err = copy_from_delta(&p, &remain, len,
380 memstream ? memstream : outfile);
386 if (*outsize != result_size)
387 err = got_error_msg(GOT_ERR_BAD_DELTA,
388 "delta application result size mismatch");
390 if (memstream != NULL) {
391 if (fclose(memstream) == EOF)
392 err = got_error_from_errno("fclose");
395 n = fwrite(memstream_buf, 1, memstream_size, outfile);
396 if (n != memstream_size)
397 err = got_ferror(outfile, GOT_ERR_IO);