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>
25 #include "got_error.h"
26 #include "got_repository.h"
27 #include "got_object.h"
34 #define MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
38 got_delta_open(const char *path_packfile, int type, off_t offset,
41 struct got_delta *delta;
43 delta = calloc(1, sizeof(*delta));
47 delta->path_packfile = strdup(path_packfile);
48 if (delta->path_packfile == NULL) {
53 delta->offset = offset;
59 got_delta_close(struct got_delta *delta)
61 free(delta->path_packfile);
66 const struct got_error *
67 got_delta_chain_get_base_type(int *type, struct got_delta_chain *deltas)
69 struct got_delta *delta;
71 /* The first delta in the chain should represent the base object. */
72 delta = SIMPLEQ_FIRST(&deltas->entries);
73 if (delta->type == GOT_OBJ_TYPE_COMMIT ||
74 delta->type == GOT_OBJ_TYPE_TREE ||
75 delta->type == GOT_OBJ_TYPE_BLOB ||
76 delta->type == GOT_OBJ_TYPE_TAG) {
81 return got_error(GOT_ERR_BAD_DELTA_CHAIN);
84 /* Fetch another (required) byte from the delta stream. */
85 static const struct got_error *
86 next_delta_byte(const uint8_t **p, size_t *remain)
89 return got_error(GOT_ERR_BAD_DELTA);
94 static const struct got_error *
95 parse_size(uint64_t *size, const uint8_t **p, size_t *remain)
97 const struct got_error *err = NULL;
102 /* We do not support size values which don't fit in 64 bit. */
104 return got_error(GOT_ERR_NO_SPACE);
107 *size = ((**p) & GOT_DELTA_SIZE_VAL_MASK);
109 size_t shift = GOT_DELTA_SIZE_SHIFT * i;
110 *size |= (((**p) & GOT_DELTA_SIZE_VAL_MASK) << shift);
113 if (((**p) & GOT_DELTA_SIZE_MORE) == 0)
116 err = next_delta_byte(p, remain);
117 } while (err == NULL);
122 static const struct got_error *
123 parse_opcode(off_t *offset, size_t *len, const uint8_t **p, size_t *remain)
125 const struct got_error *err = NULL;
128 uint8_t opcode = **p;
130 if (opcode & GOT_DELTA_COPY_OFF1) {
131 err = next_delta_byte(p, remain);
136 if (opcode & GOT_DELTA_COPY_OFF2) {
137 err = next_delta_byte(p, remain);
140 o |= ((off_t)(**p)) << 8;
142 if (opcode & GOT_DELTA_COPY_OFF3) {
143 err = next_delta_byte(p, remain);
146 o |= ((off_t)(**p)) << 16;
148 if (opcode & GOT_DELTA_COPY_OFF4) {
149 err = next_delta_byte(p, remain);
152 o |= ((off_t)(**p)) << 24;
155 if (opcode & GOT_DELTA_COPY_LEN1) {
156 err = next_delta_byte(p, remain);
161 if (opcode & GOT_DELTA_COPY_LEN2) {
162 err = next_delta_byte(p, remain);
165 l |= ((off_t)(**p)) << 8;
167 if (opcode & GOT_DELTA_COPY_LEN3) {
168 err = next_delta_byte(p, remain);
171 l |= ((off_t)(**p)) << 16;
175 o = GOT_DELTA_COPY_DEFAULT_OFF;
177 l = GOT_DELTA_COPY_DEFAULT_LEN;
184 static const struct got_error *
185 copy_from_base(FILE *base_file, off_t offset, size_t size, FILE *outfile)
187 if (fseeko(base_file, offset, SEEK_SET) != 0)
188 return got_error_from_errno();
192 size_t len = MIN(size, sizeof(data));
195 n = fread(data, len, 1, base_file);
197 return got_ferror(base_file, GOT_ERR_IO);
199 n = fwrite(data, len, 1, outfile);
201 return got_ferror(outfile, GOT_ERR_IO);
209 static const struct got_error *
210 copy_from_delta(const uint8_t **p, size_t *remain, size_t len, FILE *outfile)
215 return got_error(GOT_ERR_BAD_DELTA);
217 n = fwrite(*p, len, 1, outfile);
219 return got_ferror(outfile, GOT_ERR_IO);
226 const struct got_error *
227 got_delta_apply(FILE *base_compressed, const uint8_t *delta_buf,
228 size_t delta_len, FILE *outfile)
230 const struct got_error *err = NULL;
231 FILE *base_file = NULL;
232 uint64_t base_size, result_size;
233 size_t remain, outsize = 0;
236 if (delta_len < GOT_DELTA_STREAM_LENGTH_MIN)
237 return got_error(GOT_ERR_BAD_DELTA);
242 /* Read the two size fields at the beginning of the stream. */
243 err = parse_size(&base_size, &p, &remain);
246 err = next_delta_byte(&p, &remain);
249 err = parse_size(&result_size, &p, &remain);
253 /* Decode and execute copy instructions from the delta stream. */
254 err = next_delta_byte(&p, &remain);
255 while (err == NULL) {
256 if (*p & GOT_DELTA_BASE_COPY) {
259 err = parse_opcode(&offset, &len, &p, &remain);
262 if (base_file == NULL) {
263 size_t inflated_size;
264 base_file = got_opentemp();
265 if (base_file == NULL) {
266 err = got_error_from_errno();
269 err = got_inflate_to_file(&inflated_size,
270 base_compressed, base_file);
273 if (inflated_size != base_size) {
274 err = got_error(GOT_ERR_BAD_DELTA);
278 err = copy_from_base(base_file, offset, len, outfile);
282 size_t len = (size_t)*p;
284 err = got_error(GOT_ERR_BAD_DELTA);
287 err = next_delta_byte(&p, &remain);
290 err = copy_from_delta(&p, &remain, len, outfile);
298 /* Fetch the next instruction. */
304 if (outsize != result_size)
305 err = got_error(GOT_ERR_BAD_DELTA);