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>
29 #include "got_error.h"
30 #include "got_repository.h"
31 #include "got_object.h"
34 #include "got_lib_delta.h"
35 #include "got_lib_inflate.h"
36 #include "got_lib_object.h"
39 #define MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
43 got_delta_open(off_t offset, size_t tslen, int type, size_t size,
46 struct got_delta *delta;
48 delta = malloc(sizeof(*delta));
53 delta->offset = offset;
56 delta->data_offset = data_offset;
60 const struct got_error *
61 got_delta_chain_get_base_type(int *type, struct got_delta_chain *deltas)
63 struct got_delta *delta;
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) {
75 return got_error(GOT_ERR_BAD_DELTA_CHAIN);
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)
83 return got_error(GOT_ERR_BAD_DELTA);
88 static const struct got_error *
89 parse_size(uint64_t *size, const uint8_t **p, size_t *remain)
91 const struct got_error *err = NULL;
96 /* We do not support size values which don't fit in 64 bit. */
98 return got_error(GOT_ERR_NO_SPACE);
101 *size = ((**p) & GOT_DELTA_SIZE_VAL_MASK);
103 size_t shift = GOT_DELTA_SIZE_SHIFT * i;
104 *size |= (((**p) & GOT_DELTA_SIZE_VAL_MASK) << shift);
107 if (((**p) & GOT_DELTA_SIZE_MORE) == 0)
110 err = next_delta_byte(p, remain);
111 } while (err == NULL);
116 static const struct got_error *
117 parse_opcode(off_t *offset, size_t *len, const uint8_t **p, size_t *remain)
119 const struct got_error *err = NULL;
122 uint8_t opcode = **p;
124 if (opcode & GOT_DELTA_COPY_OFF1) {
125 err = next_delta_byte(p, remain);
130 if (opcode & GOT_DELTA_COPY_OFF2) {
131 err = next_delta_byte(p, remain);
134 o |= ((off_t)(**p)) << 8;
136 if (opcode & GOT_DELTA_COPY_OFF3) {
137 err = next_delta_byte(p, remain);
140 o |= ((off_t)(**p)) << 16;
142 if (opcode & GOT_DELTA_COPY_OFF4) {
143 err = next_delta_byte(p, remain);
146 o |= ((off_t)(**p)) << 24;
149 if (opcode & GOT_DELTA_COPY_LEN1) {
150 err = next_delta_byte(p, remain);
155 if (opcode & GOT_DELTA_COPY_LEN2) {
156 err = next_delta_byte(p, remain);
159 l |= ((off_t)(**p)) << 8;
161 if (opcode & GOT_DELTA_COPY_LEN3) {
162 err = next_delta_byte(p, remain);
165 l |= ((off_t)(**p)) << 16;
169 o = GOT_DELTA_COPY_DEFAULT_OFF;
171 l = GOT_DELTA_COPY_DEFAULT_LEN;
178 static const struct got_error *
179 copy_from_base(FILE *base_file, off_t offset, size_t size, FILE *outfile)
181 if (fseeko(base_file, offset, SEEK_SET) != 0)
182 return got_error_from_errno("fseeko");
186 size_t len = MIN(size, sizeof(data));
189 n = fread(data, len, 1, base_file);
191 return got_ferror(base_file, GOT_ERR_IO);
193 n = fwrite(data, len, 1, outfile);
195 return got_ferror(outfile, GOT_ERR_IO);
203 static const struct got_error *
204 copy_from_delta(const uint8_t **p, size_t *remain, size_t len, FILE *outfile)
209 return got_error(GOT_ERR_BAD_DELTA);
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(GOT_ERR_BAD_DELTA);
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(GOT_ERR_BAD_DELTA);
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(GOT_ERR_BAD_DELTA);
289 memcpy(outbuf + *outsize, base_buf + offset, len);
298 size_t len = (size_t)*p;
300 err = got_error(GOT_ERR_BAD_DELTA);
303 err = next_delta_byte(&p, &remain);
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);
316 if (*outsize != result_size)
317 err = got_error(GOT_ERR_BAD_DELTA);
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)
325 const struct got_error *err = NULL;
326 uint64_t base_size, result_size;
329 FILE *memstream = NULL;
330 char *memstream_buf = NULL;
331 size_t memstream_size = 0;
335 if (delta_len < GOT_DELTA_STREAM_LENGTH_MIN)
336 return got_error(GOT_ERR_BAD_DELTA);
340 err = parse_delta_sizes(&base_size, &result_size, &p, &remain);
344 if (result_size < GOT_DELTA_RESULT_SIZE_CACHED_MAX)
345 memstream = open_memstream(&memstream_buf, &memstream_size);
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) {
353 err = parse_opcode(&offset, &len, &p, &remain);
356 err = copy_from_base(base_file, offset, len,
357 memstream ? memstream : outfile);
366 size_t len = (size_t)*p;
368 err = got_error(GOT_ERR_BAD_DELTA);
371 err = next_delta_byte(&p, &remain);
374 err = copy_from_delta(&p, &remain, len,
375 memstream ? memstream : outfile);
381 if (*outsize != result_size)
382 err = got_error(GOT_ERR_BAD_DELTA);
384 if (memstream != NULL) {
385 if (fclose(memstream) != 0)
386 err = got_error_from_errno("fclose");
389 n = fwrite(memstream_buf, 1, memstream_size, outfile);
390 if (n != memstream_size)
391 err = got_ferror(outfile, GOT_ERR_IO);