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,
43 off_t data_offset, uint8_t *delta_buf, size_t delta_len)
45 struct got_delta *delta;
47 delta = malloc(sizeof(*delta));
52 delta->offset = offset;
55 delta->data_offset = data_offset;
56 delta->delta_buf = delta_buf;
57 delta->delta_len = delta_len;
61 const struct got_error *
62 got_delta_chain_get_base_type(int *type, struct got_delta_chain *deltas)
64 struct got_delta *delta;
66 /* The first delta in the chain should represent the base object. */
67 delta = SIMPLEQ_FIRST(&deltas->entries);
68 if (delta->type == GOT_OBJ_TYPE_COMMIT ||
69 delta->type == GOT_OBJ_TYPE_TREE ||
70 delta->type == GOT_OBJ_TYPE_BLOB ||
71 delta->type == GOT_OBJ_TYPE_TAG) {
76 return got_error(GOT_ERR_BAD_DELTA_CHAIN);
79 /* Fetch another (required) byte from the delta stream. */
80 static const struct got_error *
81 next_delta_byte(const uint8_t **p, size_t *remain)
84 return got_error(GOT_ERR_BAD_DELTA);
89 static const struct got_error *
90 parse_size(uint64_t *size, const uint8_t **p, size_t *remain)
92 const struct got_error *err = NULL;
97 /* We do not support size values which don't fit in 64 bit. */
99 return got_error(GOT_ERR_NO_SPACE);
102 *size = ((**p) & GOT_DELTA_SIZE_VAL_MASK);
104 size_t shift = GOT_DELTA_SIZE_SHIFT * i;
105 *size |= (((**p) & GOT_DELTA_SIZE_VAL_MASK) << shift);
108 if (((**p) & GOT_DELTA_SIZE_MORE) == 0)
111 err = next_delta_byte(p, remain);
112 } while (err == NULL);
117 static const struct got_error *
118 parse_opcode(off_t *offset, size_t *len, const uint8_t **p, size_t *remain)
120 const struct got_error *err = NULL;
123 uint8_t opcode = **p;
125 if (opcode & GOT_DELTA_COPY_OFF1) {
126 err = next_delta_byte(p, remain);
131 if (opcode & GOT_DELTA_COPY_OFF2) {
132 err = next_delta_byte(p, remain);
135 o |= ((off_t)(**p)) << 8;
137 if (opcode & GOT_DELTA_COPY_OFF3) {
138 err = next_delta_byte(p, remain);
141 o |= ((off_t)(**p)) << 16;
143 if (opcode & GOT_DELTA_COPY_OFF4) {
144 err = next_delta_byte(p, remain);
147 o |= ((off_t)(**p)) << 24;
150 if (opcode & GOT_DELTA_COPY_LEN1) {
151 err = next_delta_byte(p, remain);
156 if (opcode & GOT_DELTA_COPY_LEN2) {
157 err = next_delta_byte(p, remain);
160 l |= ((off_t)(**p)) << 8;
162 if (opcode & GOT_DELTA_COPY_LEN3) {
163 err = next_delta_byte(p, remain);
166 l |= ((off_t)(**p)) << 16;
170 o = GOT_DELTA_COPY_DEFAULT_OFF;
172 l = GOT_DELTA_COPY_DEFAULT_LEN;
179 static const struct got_error *
180 copy_from_base(FILE *base_file, off_t offset, size_t size, FILE *outfile)
182 if (fseeko(base_file, offset, SEEK_SET) != 0)
183 return got_error_from_errno("fseeko");
187 size_t len = MIN(size, sizeof(data));
190 n = fread(data, len, 1, base_file);
192 return got_ferror(base_file, GOT_ERR_IO);
194 n = fwrite(data, len, 1, outfile);
196 return got_ferror(outfile, GOT_ERR_IO);
204 static const struct got_error *
205 copy_from_delta(const uint8_t **p, size_t *remain, size_t len, FILE *outfile)
210 return got_error(GOT_ERR_BAD_DELTA);
212 n = fwrite(*p, len, 1, outfile);
214 return got_ferror(outfile, GOT_ERR_IO);
221 static const struct got_error *
222 parse_delta_sizes(uint64_t *base_size, uint64_t *result_size,
223 const uint8_t **p, size_t *remain)
225 const struct got_error *err;
227 /* Read the two size fields at the beginning of the stream. */
228 err = parse_size(base_size, p, remain);
231 err = next_delta_byte(p, remain);
234 err = parse_size(result_size, p, remain);
241 const struct got_error *
242 got_delta_get_sizes(uint64_t *base_size, uint64_t *result_size,
243 const uint8_t *delta_buf, size_t delta_len)
248 if (delta_len < GOT_DELTA_STREAM_LENGTH_MIN)
249 return got_error(GOT_ERR_BAD_DELTA);
253 return parse_delta_sizes(base_size, result_size, &p, &remain);
256 const struct got_error *
257 got_delta_apply_in_mem(uint8_t *base_buf, size_t base_bufsz,
258 const uint8_t *delta_buf, size_t delta_len, uint8_t *outbuf,
259 size_t *outsize, size_t maxoutsize)
261 const struct got_error *err = NULL;
262 uint64_t base_size, result_size;
268 if (delta_len < GOT_DELTA_STREAM_LENGTH_MIN)
269 return got_error(GOT_ERR_BAD_DELTA);
273 err = parse_delta_sizes(&base_size, &result_size, &p, &remain);
277 /* Decode and execute copy instructions from the delta stream. */
278 err = next_delta_byte(&p, &remain);
279 while (err == NULL && remain > 0) {
280 if (*p & GOT_DELTA_BASE_COPY) {
283 err = parse_opcode(&offset, &len, &p, &remain);
286 if (SIZE_MAX - offset < len || offset + len < 0 ||
287 base_bufsz < offset + len ||
288 *outsize + len > maxoutsize)
289 return got_error(GOT_ERR_BAD_DELTA);
290 memcpy(outbuf + *outsize, base_buf + offset, len);
299 size_t len = (size_t)*p;
301 err = got_error(GOT_ERR_BAD_DELTA);
304 err = next_delta_byte(&p, &remain);
307 if (remain < len || SIZE_MAX - *outsize < len ||
308 *outsize + len > maxoutsize)
309 return got_error(GOT_ERR_BAD_DELTA);
310 memcpy(outbuf + *outsize, p, len);
317 if (*outsize != result_size)
318 err = got_error(GOT_ERR_BAD_DELTA);
322 const struct got_error *
323 got_delta_apply(FILE *base_file, const uint8_t *delta_buf,
324 size_t delta_len, FILE *outfile, size_t *outsize)
326 const struct got_error *err = NULL;
327 uint64_t base_size, result_size;
330 FILE *memstream = NULL;
331 char *memstream_buf = NULL;
332 size_t memstream_size = 0;
336 if (delta_len < GOT_DELTA_STREAM_LENGTH_MIN)
337 return got_error(GOT_ERR_BAD_DELTA);
341 err = parse_delta_sizes(&base_size, &result_size, &p, &remain);
345 if (result_size < GOT_DELTA_RESULT_SIZE_CACHED_MAX)
346 memstream = open_memstream(&memstream_buf, &memstream_size);
348 /* Decode and execute copy instructions from the delta stream. */
349 err = next_delta_byte(&p, &remain);
350 while (err == NULL && remain > 0) {
351 if (*p & GOT_DELTA_BASE_COPY) {
354 err = parse_opcode(&offset, &len, &p, &remain);
357 err = copy_from_base(base_file, offset, len,
358 memstream ? memstream : outfile);
367 size_t len = (size_t)*p;
369 err = got_error(GOT_ERR_BAD_DELTA);
372 err = next_delta_byte(&p, &remain);
375 err = copy_from_delta(&p, &remain, len,
376 memstream ? memstream : outfile);
382 if (*outsize != result_size)
383 err = got_error(GOT_ERR_BAD_DELTA);
385 if (memstream != NULL) {
386 if (fclose(memstream) != 0)
387 err = got_error_from_errno("fclose");
390 n = fwrite(memstream_buf, 1, memstream_size, outfile);
391 if (n != memstream_size)
392 err = got_ferror(outfile, GOT_ERR_IO);