Annotation of src/usr.bin/rsync/blocks.c, Revision 1.15
1.15 ! benno 1: /* $Id: blocks.c,v 1.14 2019/03/23 16:04:28 deraadt Exp $ */
1.1 benno 2: /*
3: * Copyright (c) 2019 Kristaps Dzonsons <kristaps@bsd.lv>
4: *
5: * Permission to use, copy, modify, and distribute this software for any
6: * purpose with or without fee is hereby granted, provided that the above
7: * copyright notice and this permission notice appear in all copies.
8: *
9: * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10: * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11: * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12: * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13: * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14: * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15: * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16: */
17: #include <sys/stat.h>
18:
19: #include <assert.h>
20: #include <endian.h>
21: #include <errno.h>
22: #include <inttypes.h>
23: #include <stdio.h>
24: #include <stdlib.h>
25: #include <string.h>
26: #include <unistd.h>
27:
1.6 tb 28: #include <openssl/md4.h>
29:
1.1 benno 30: #include "extern.h"
31:
32: /*
33: * From our current position of "offs" in buffer "buf" of total size
34: * "size", see if we can find a matching block in our list of blocks.
35: * The "hint" refers to the block that *might* work.
36: * Returns the blk or NULL if no matching block was found.
37: */
38: static struct blk *
39: blk_find(struct sess *sess, const void *buf, off_t size, off_t offs,
40: const struct blkset *blks, const char *path, size_t hint)
41: {
42: unsigned char md[MD4_DIGEST_LENGTH];
43: uint32_t fhash;
44: off_t remain, osz;
45: size_t i;
46: int have_md = 0;
47:
48: /*
49: * First, compute our fast hash.
50: * FIXME: yes, this can be a rolling computation, but I'm
51: * deliberately making it simple first.
52: */
53:
54: remain = size - offs;
55: assert(remain);
56: osz = remain < (off_t)blks->len ? remain : (off_t)blks->len;
57: fhash = hash_fast(buf + offs, (size_t)osz);
58: have_md = 0;
59:
60: /*
61: * Start with our match hint.
62: * This just runs the fast and slow check with the hint.
63: */
64:
65: if (hint < blks->blksz &&
66: fhash == blks->blks[hint].chksum_short &&
67: (size_t)osz == blks->blks[hint].len) {
68: hash_slow(buf + offs, (size_t)osz, md, sess);
69: have_md = 1;
1.4 deraadt 70: if (memcmp(md, blks->blks[hint].chksum_long, blks->csum) == 0) {
1.15 ! benno 71: LOG4("%s: found matching hinted match: "
1.14 deraadt 72: "position %jd, block %zu (position %jd, size %zu)",
73: path,
74: (intmax_t)offs, blks->blks[hint].idx,
75: (intmax_t)blks->blks[hint].offs,
76: blks->blks[hint].len);
1.1 benno 77: return &blks->blks[hint];
78: }
79: }
80:
81: /*
82: * Now loop and look for the fast hash.
83: * If it's found, move on to the slow hash.
84: */
85:
86: for (i = 0; i < blks->blksz; i++) {
87: if (fhash != blks->blks[i].chksum_short)
88: continue;
89: if ((size_t)osz != blks->blks[i].len)
90: continue;
91:
1.15 ! benno 92: LOG4("%s: found matching fast match: "
1.14 deraadt 93: "position %jd, block %zu (position %jd, size %zu)",
94: path,
95: (intmax_t)offs, blks->blks[i].idx,
96: (intmax_t)blks->blks[i].offs,
97: blks->blks[i].len);
1.1 benno 98:
99: /* Compute slow hash on demand. */
100:
1.4 deraadt 101: if (have_md == 0) {
1.1 benno 102: hash_slow(buf + offs, (size_t)osz, md, sess);
103: have_md = 1;
104: }
105:
106: if (memcmp(md, blks->blks[i].chksum_long, blks->csum))
107: continue;
108:
1.15 ! benno 109: LOG4("%s: sender verifies slow match", path);
1.1 benno 110: return &blks->blks[i];
111: }
112:
113: return NULL;
114: }
115:
116: /*
117: * Given a local file "path" and the blocks created by a remote machine,
118: * find out which blocks of our file they don't have and send them.
1.7 florian 119: * This function is reentrant: it must be called while there's still
120: * data to send.
1.1 benno 121: */
1.9 florian 122: void
123: blk_match(struct sess *sess, const struct blkset *blks,
1.7 florian 124: const char *path, struct blkstat *st)
1.1 benno 125: {
1.9 florian 126: off_t last, end, sz;
127: int32_t tok;
128: struct blk *blk;
1.1 benno 129:
130: /*
131: * If the file's empty or we don't have any blocks from the
132: * sender, then simply send the whole file.
133: * Otherwise, run the hash matching routine and send raw chunks
134: * and subsequent matching tokens.
135: */
136:
1.7 florian 137: if (st->mapsz && blks->blksz) {
1.9 florian 138: /*
139: * Stop searching at the length of the file minus the
140: * size of the last block.
141: * The reason for this being that we don't need to do an
142: * incremental hash within the last block---if it
143: * doesn't match, it doesn't match.
144: */
145:
146: end = st->mapsz + 1 - blks->blks[blks->blksz - 1].len;
147: last = st->offs;
148:
149: for ( ; st->offs < end; st->offs++) {
150: blk = blk_find(sess, st->map, st->mapsz,
151: st->offs, blks, path, st->hint);
152: if (blk == NULL)
153: continue;
154:
155: sz = st->offs - last;
156: st->dirty += sz;
157: st->total += sz;
1.15 ! benno 158: LOG4("%s: flushing %jd B before %zu B block %zu",
1.14 deraadt 159: path, (intmax_t)sz,
160: blk->len, blk->idx);
1.9 florian 161: tok = -(blk->idx + 1);
162:
163: /*
164: * Write the data we have, then follow it with
165: * the tag of the block that matches.
166: */
167:
168: st->curpos = last;
169: st->curlen = st->curpos + sz;
170: st->curtok = tok;
1.10 deraadt 171: assert(st->curtok != 0);
1.9 florian 172: st->curst = sz ? BLKSTAT_DATA : BLKSTAT_TOK;
173: st->total += blk->len;
174: st->offs += blk->len;
175: st->hint = blk->idx + 1;
176: return;
1.1 benno 177: }
178:
1.9 florian 179: /* Emit remaining data and send terminator token. */
180:
181: sz = st->mapsz - last;
1.15 ! benno 182: LOG4("%s: flushing remaining %jd B",
1.14 deraadt 183: path, (intmax_t)sz);
1.1 benno 184:
1.9 florian 185: st->total += sz;
186: st->dirty += sz;
187: st->curpos = last;
188: st->curlen = st->curpos + sz;
189: st->curtok = 0;
190: st->curst = sz ? BLKSTAT_DATA : BLKSTAT_TOK;
191: } else {
192: st->curpos = 0;
193: st->curlen = st->mapsz;
194: st->curtok = 0;
195: st->curst = st->mapsz ? BLKSTAT_DATA : BLKSTAT_TOK;
196: st->dirty = st->total = st->mapsz;
1.1 benno 197:
1.15 ! benno 198: LOG4("%s: flushing whole file %zu B",
1.14 deraadt 199: path, st->mapsz);
1.1 benno 200: }
201: }
202:
203: /*
1.13 benno 204: * Buffer the message from sender to the receiver indicating that the
205: * block set has been received.
1.1 benno 206: * Symmetrises blk_send_ack().
207: */
1.13 benno 208: void
209: blk_recv_ack(struct sess *sess, char buf[20],
210: const struct blkset *blocks, int32_t idx)
1.1 benno 211: {
1.8 florian 212: size_t pos = 0, sz;
1.1 benno 213:
1.8 florian 214: sz = sizeof(int32_t) + /* index */
215: sizeof(int32_t) + /* block count */
216: sizeof(int32_t) + /* block length */
217: sizeof(int32_t) + /* checksum length */
218: sizeof(int32_t); /* block remainder */
1.13 benno 219: assert(sz == 20);
1.8 florian 220:
221: io_buffer_int(sess, buf, &pos, sz, idx);
222: io_buffer_int(sess, buf, &pos, sz, blocks->blksz);
223: io_buffer_int(sess, buf, &pos, sz, blocks->len);
224: io_buffer_int(sess, buf, &pos, sz, blocks->csum);
225: io_buffer_int(sess, buf, &pos, sz, blocks->rem);
226: assert(pos == sz);
1.1 benno 227: }
228:
229: /*
230: * Read all of the checksums for a file's blocks.
231: * Returns the set of blocks or NULL on failure.
232: */
233: struct blkset *
234: blk_recv(struct sess *sess, int fd, const char *path)
235: {
236: struct blkset *s;
237: int32_t i;
238: size_t j;
239: struct blk *b;
240: off_t offs = 0;
241:
1.4 deraadt 242: if ((s = calloc(1, sizeof(struct blkset))) == NULL) {
1.15 ! benno 243: ERR("calloc");
1.1 benno 244: return NULL;
245: }
246:
247: /*
248: * The block prologue consists of a few values that we'll need
249: * in reading the individual blocks for this file.
250: * FIXME: read into buffer and unbuffer.
251: */
252:
1.3 deraadt 253: if (!io_read_size(sess, fd, &s->blksz)) {
1.15 ! benno 254: ERRX1("io_read_size");
1.1 benno 255: goto out;
1.3 deraadt 256: } else if (!io_read_size(sess, fd, &s->len)) {
1.15 ! benno 257: ERRX1("io_read_size");
1.1 benno 258: goto out;
1.3 deraadt 259: } else if (!io_read_size(sess, fd, &s->csum)) {
1.15 ! benno 260: ERRX1("io_read_int");
1.1 benno 261: goto out;
1.3 deraadt 262: } else if (!io_read_size(sess, fd, &s->rem)) {
1.15 ! benno 263: ERRX1("io_read_int");
1.1 benno 264: goto out;
265: } else if (s->rem && s->rem >= s->len) {
1.15 ! benno 266: ERRX("block remainder is "
1.1 benno 267: "greater than block size");
268: goto out;
269: }
270:
1.15 ! benno 271: LOG3("%s: read block prologue: %zu blocks of "
1.14 deraadt 272: "%zu B, %zu B remainder, %zu B checksum", path,
273: s->blksz, s->len, s->rem, s->csum);
1.1 benno 274:
275: if (s->blksz) {
276: s->blks = calloc(s->blksz, sizeof(struct blk));
1.4 deraadt 277: if (s->blks == NULL) {
1.15 ! benno 278: ERR("calloc");
1.1 benno 279: goto out;
280: }
281: }
282:
1.2 benno 283: /*
1.1 benno 284: * Read each block individually.
285: * FIXME: read buffer and unbuffer.
286: */
287:
288: for (j = 0; j < s->blksz; j++) {
289: b = &s->blks[j];
1.3 deraadt 290: if (!io_read_int(sess, fd, &i)) {
1.15 ! benno 291: ERRX1("io_read_int");
1.1 benno 292: goto out;
293: }
294: b->chksum_short = i;
295:
296: assert(s->csum <= sizeof(b->chksum_long));
1.3 deraadt 297: if (!io_read_buf(sess,
1.1 benno 298: fd, b->chksum_long, s->csum)) {
1.15 ! benno 299: ERRX1("io_read_buf");
1.1 benno 300: goto out;
301: }
302:
303: /*
304: * If we're the last block, then we're assigned the
305: * remainder of the data.
306: */
307:
308: b->offs = offs;
309: b->idx = j;
310: b->len = (j == (s->blksz - 1) && s->rem) ?
311: s->rem : s->len;
312: offs += b->len;
313:
1.15 ! benno 314: LOG4("%s: read block %zu, length %zu B",
1.14 deraadt 315: path, b->idx, b->len);
1.1 benno 316: }
317:
318: s->size = offs;
1.15 ! benno 319: LOG3("%s: read blocks: %zu blocks, %jd B total blocked data",
1.14 deraadt 320: path, s->blksz, (intmax_t)s->size);
1.1 benno 321: return s;
322: out:
1.7 florian 323: free(s->blks);
324: free(s);
1.1 benno 325: return NULL;
326: }
327:
328: /*
329: * Symmetrise blk_recv_ack(), except w/o the leading identifier.
330: * Return zero on failure, non-zero on success.
331: */
332: int
333: blk_send_ack(struct sess *sess, int fd, struct blkset *p)
334: {
335: char buf[16];
336: size_t pos = 0, sz;
337:
338: /* Put the entire send routine into a buffer. */
339:
340: sz = sizeof(int32_t) + /* block count */
341: sizeof(int32_t) + /* block length */
342: sizeof(int32_t) + /* checksum length */
343: sizeof(int32_t); /* block remainder */
344: assert(sz <= sizeof(buf));
345:
1.3 deraadt 346: if (!io_read_buf(sess, fd, buf, sz)) {
1.15 ! benno 347: ERRX1("io_read_buf");
1.1 benno 348: return 0;
349: }
350:
1.3 deraadt 351: if (!io_unbuffer_size(sess, buf, &pos, sz, &p->blksz))
1.15 ! benno 352: ERRX1("io_unbuffer_size");
1.3 deraadt 353: else if (!io_unbuffer_size(sess, buf, &pos, sz, &p->len))
1.15 ! benno 354: ERRX1("io_unbuffer_size");
1.3 deraadt 355: else if (!io_unbuffer_size(sess, buf, &pos, sz, &p->csum))
1.15 ! benno 356: ERRX1("io_unbuffer_size");
1.3 deraadt 357: else if (!io_unbuffer_size(sess, buf, &pos, sz, &p->rem))
1.15 ! benno 358: ERRX1("io_unbuffer_size");
1.1 benno 359: else if (p->len && p->rem >= p->len)
1.15 ! benno 360: ERRX1("non-zero length is less than remainder");
1.4 deraadt 361: else if (p->csum == 0 || p->csum > 16)
1.15 ! benno 362: ERRX1("inappropriate checksum length");
1.1 benno 363: else
364: return 1;
365:
366: return 0;
367: }
368:
369: /*
370: * Transmit the metadata for set and blocks.
371: * Return zero on failure, non-zero on success.
372: */
373: int
374: blk_send(struct sess *sess, int fd, size_t idx,
375: const struct blkset *p, const char *path)
376: {
377: char *buf;
378: size_t i, pos = 0, sz;
379: int rc = 0;
380:
381: /* Put the entire send routine into a buffer. */
382:
383: sz = sizeof(int32_t) + /* identifier */
1.2 benno 384: sizeof(int32_t) + /* block count */
385: sizeof(int32_t) + /* block length */
386: sizeof(int32_t) + /* checksum length */
387: sizeof(int32_t) + /* block remainder */
388: p->blksz *
389: (sizeof(int32_t) + /* short checksum */
390: p->csum); /* long checksum */
1.1 benno 391:
1.4 deraadt 392: if ((buf = malloc(sz)) == NULL) {
1.15 ! benno 393: ERR("malloc");
1.1 benno 394: return 0;
395: }
396:
397: io_buffer_int(sess, buf, &pos, sz, idx);
398: io_buffer_int(sess, buf, &pos, sz, p->blksz);
399: io_buffer_int(sess, buf, &pos, sz, p->len);
400: io_buffer_int(sess, buf, &pos, sz, p->csum);
401: io_buffer_int(sess, buf, &pos, sz, p->rem);
402:
403: for (i = 0; i < p->blksz; i++) {
1.2 benno 404: io_buffer_int(sess, buf, &pos,
1.1 benno 405: sz, p->blks[i].chksum_short);
1.2 benno 406: io_buffer_buf(sess, buf, &pos, sz,
1.1 benno 407: p->blks[i].chksum_long, p->csum);
408: }
409:
410: assert(pos == sz);
411:
1.3 deraadt 412: if (!io_write_buf(sess, fd, buf, sz)) {
1.15 ! benno 413: ERRX1("io_write_buf");
1.1 benno 414: goto out;
415: }
416:
1.15 ! benno 417: LOG3("%s: sent block prologue: %zu blocks of %zu B, "
1.14 deraadt 418: "%zu B remainder, %zu B checksum",
419: path, p->blksz, p->len, p->rem, p->csum);
1.1 benno 420: rc = 1;
421: out:
422: free(buf);
423: return rc;
424: }
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