Annotation of src/usr.bin/rsync/downloader.c, Revision 1.5
1.5 ! benno 1: /* $Id: downloader.c,v 1.4 2019/02/11 21:41:22 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/mman.h>
18: #include <sys/stat.h>
19:
20: #include <assert.h>
21: #include <errno.h>
22: #include <fcntl.h>
23: #include <inttypes.h>
24: #include <math.h>
25: #include <poll.h>
26: #include <stdio.h>
27: #include <stdlib.h>
28: #include <string.h>
29: #include <time.h>
30: #include <unistd.h>
31:
32: #include "extern.h"
33: #include "md4.h"
34:
35: /*
36: * A small optimisation: have a 1 MB pre-write buffer.
37: * Disable the pre-write buffer by having this be zero.
38: * (It doesn't affect performance much.)
39: */
40: #define OBUF_SIZE (1024 * 1024)
41:
42: enum downloadst {
43: DOWNLOAD_READ_NEXT = 0,
44: DOWNLOAD_READ_LOCAL,
45: DOWNLOAD_READ_REMOTE
46: };
47:
48: /*
49: * Like struct upload, but used to keep track of what we're downloading.
50: * This also is managed by the receiver process.
51: */
52: struct download {
53: enum downloadst state; /* state of affairs */
1.2 benno 54: size_t idx; /* index of current file */
1.1 benno 55: struct blkset blk; /* its blocks */
56: void *map; /* mmap of current file */
57: size_t mapsz; /* length of mapsz */
58: int ofd; /* open origin file */
59: int fd; /* open output file */
60: char *fname; /* output filename */
1.2 benno 61: MD4_CTX ctx; /* current hashing context */
1.1 benno 62: off_t downloaded; /* total downloaded */
63: off_t total; /* total in file */
64: const struct flist *fl; /* file list */
65: size_t flsz; /* size of file list */
66: int rootfd; /* destination directory */
67: int fdin; /* read descriptor from sender */
68: char *obuf; /* pre-write buffer */
69: size_t obufsz; /* current size of obuf */
70: size_t obufmax; /* max size we'll wbuffer */
71: };
72:
73:
74: /*
75: * Simply log the filename.
76: */
77: static void
1.2 benno 78: log_file(struct sess *sess,
1.1 benno 79: const struct download *dl, const struct flist *f)
80: {
81: float frac, tot = dl->total;
82: int prec = 0;
83: const char *unit = "B";
84:
85: if (sess->opts->server)
86: return;
87:
1.2 benno 88: frac = 0 == dl->total ? 100.0 :
1.1 benno 89: 100.0 * dl->downloaded / dl->total;
90:
91: if (dl->total > 1024 * 1024 * 1024) {
92: tot = dl->total / (1024. * 1024. * 1024.);
93: prec = 3;
94: unit = "GB";
95: } else if (dl->total > 1024 * 1024) {
96: tot = dl->total / (1024. * 1024.);
97: prec = 2;
98: unit = "MB";
99: } else if (dl->total > 1024) {
100: tot = dl->total / 1024.;
101: prec = 1;
102: unit = "KB";
103: }
104:
1.2 benno 105: LOG1(sess, "%s (%.*f %s, %.1f%% downloaded)",
1.1 benno 106: f->path, prec, tot, unit, frac);
107: }
108:
109: /*
110: * Reinitialise a download context w/o overwriting the persistent parts
111: * of the structure (like p->fl or p->flsz) for index "idx".
112: * The MD4 context is pre-seeded.
113: */
114: static void
115: download_reinit(struct sess *sess, struct download *p, size_t idx)
116: {
117: int32_t seed = htole32(sess->seed);
118:
1.4 deraadt 119: assert(p->state == DOWNLOAD_READ_NEXT);
1.1 benno 120:
121: p->idx = idx;
122: memset(&p->blk, 0, sizeof(struct blkset));
123: p->map = MAP_FAILED;
124: p->mapsz = 0;
125: p->ofd = -1;
126: p->fd = -1;
127: p->fname = NULL;
128: MD4_Init(&p->ctx);
129: p->downloaded = p->total = 0;
130: /* Don't touch p->fl. */
131: /* Don't touch p->flsz. */
132: /* Don't touch p->rootfd. */
133: /* Don't touch p->fdin. */
134: MD4_Update(&p->ctx, &seed, sizeof(int32_t));
135: }
136:
137: /*
138: * Free a download context.
139: * If "cleanup" is non-zero, we also try to clean up the temporary file,
140: * assuming that it has been opened in p->fd.
141: */
142: static void
143: download_cleanup(struct download *p, int cleanup)
144: {
145:
1.4 deraadt 146: if (p->map != MAP_FAILED) {
1.1 benno 147: assert(p->mapsz);
148: munmap(p->map, p->mapsz);
149: p->map = MAP_FAILED;
150: p->mapsz = 0;
151: }
1.4 deraadt 152: if (p->ofd != -1) {
1.1 benno 153: close(p->ofd);
154: p->ofd = -1;
155: }
1.4 deraadt 156: if (p->fd != -1) {
1.1 benno 157: close(p->fd);
1.4 deraadt 158: if (cleanup && p->fname != NULL)
1.1 benno 159: unlinkat(p->rootfd, p->fname, 0);
160: p->fd = -1;
161: }
162: free(p->fname);
163: p->fname = NULL;
164: p->state = DOWNLOAD_READ_NEXT;
165: }
166:
167: /*
168: * Initial allocation of the download object using the file list "fl" of
169: * size "flsz", the destination "rootfd", and the sender read "fdin".
170: * Returns NULL on allocation failure.
171: * On success, download_free() must be called with the pointer.
172: */
173: struct download *
1.2 benno 174: download_alloc(struct sess *sess, int fdin,
1.1 benno 175: const struct flist *fl, size_t flsz, int rootfd)
176: {
177: struct download *p;
178:
1.4 deraadt 179: if ((p = malloc(sizeof(struct download))) == NULL) {
1.1 benno 180: ERR(sess, "malloc");
181: return NULL;
182: }
183:
184: p->state = DOWNLOAD_READ_NEXT;
185: p->fl = fl;
186: p->flsz = flsz;
187: p->rootfd = rootfd;
188: p->fdin = fdin;
189: download_reinit(sess, p, 0);
190: p->obufsz = 0;
191: p->obuf = NULL;
192: p->obufmax = OBUF_SIZE;
1.4 deraadt 193: if (p->obufmax && (p->obuf = malloc(p->obufmax)) == NULL) {
1.1 benno 194: ERR(sess, "malloc");
195: free(p);
196: return NULL;
197: }
198: return p;
199: }
200:
201: /*
202: * Perform all cleanups (including removing stray files) and free.
203: * Passing a NULL to this function is ok.
204: */
205: void
206: download_free(struct download *p)
207: {
208:
1.4 deraadt 209: if (p == NULL)
1.1 benno 210: return;
211: download_cleanup(p, 1);
212: free(p->obuf);
213: free(p);
214: }
215:
216: /*
217: * Optimisation: instead of dumping directly into the output file, keep
218: * a buffer and write as much as we can into the buffer.
219: * That way, we can avoid calling write() too much, and instead call it
220: * with big buffers.
221: * To flush the buffer w/o changing it, pass 0 as "sz".
222: * Returns zero on failure, non-zero on success.
223: */
224: static int
1.2 benno 225: buf_copy(struct sess *sess,
1.1 benno 226: const char *buf, size_t sz, struct download *p)
227: {
228: size_t rem, tocopy;
229: ssize_t ssz;
230:
231: assert(p->obufsz <= p->obufmax);
232:
1.2 benno 233: /*
1.1 benno 234: * Copy as much as we can.
235: * If we've copied everything, exit.
236: * If we have no pre-write buffer (obufmax of zero), this never
237: * gets called, so we never buffer anything.
238: */
239:
240: if (sz && p->obufsz < p->obufmax) {
1.4 deraadt 241: assert(p->obuf != NULL);
1.1 benno 242: rem = p->obufmax - p->obufsz;
243: assert(rem > 0);
244: tocopy = rem < sz ? rem : sz;
245: memcpy(p->obuf + p->obufsz, buf, tocopy);
246: sz -= tocopy;
247: buf += tocopy;
248: p->obufsz += tocopy;
249: assert(p->obufsz <= p->obufmax);
1.4 deraadt 250: if (sz == 0)
1.1 benno 251: return 1;
252: }
253:
254: /* Drain the main buffer. */
255:
256: if (p->obufsz) {
257: assert(p->obufmax);
258: assert(p->obufsz <= p->obufmax);
1.4 deraadt 259: assert(p->obuf != NULL);
1.1 benno 260: if ((ssz = write(p->fd, p->obuf, p->obufsz)) < 0) {
261: ERR(sess, "%s: write", p->fname);
262: return 0;
263: } else if ((size_t)ssz != p->obufsz) {
264: ERRX(sess, "%s: short write", p->fname);
265: return 0;
266: }
267: p->obufsz = 0;
268: }
269:
1.2 benno 270: /*
1.1 benno 271: * Now drain anything left.
272: * If we have no pre-write buffer, this is it.
273: */
274:
275: if (sz) {
276: if ((ssz = write(p->fd, buf, sz)) < 0) {
277: ERR(sess, "%s: write", p->fname);
278: return 0;
279: } else if ((size_t)ssz != sz) {
280: ERRX(sess, "%s: short write", p->fname);
281: return 0;
282: }
283: }
284: return 1;
285: }
286:
287: /*
288: * The downloader waits on a file the sender is going to give us, opens
289: * and mmaps the existing file, opens a temporary file, dumps the file
290: * (or metadata) into the temporary file, then renames.
291: * This happens in several possible phases to avoid blocking.
292: * Returns <0 on failure, 0 on no more data (end of phase), >0 on
293: * success (more data to be read from the sender).
294: */
295: int
296: rsync_downloader(struct download *p, struct sess *sess, int *ofd)
297: {
298: int32_t idx, rawtok;
299: uint32_t hash;
300: const struct flist *f;
301: size_t sz, dirlen, tok;
302: const char *cp;
303: mode_t perm;
1.2 benno 304: struct stat st;
1.1 benno 305: char *buf = NULL;
1.2 benno 306: unsigned char ourmd[MD4_DIGEST_LENGTH],
1.1 benno 307: md[MD4_DIGEST_LENGTH];
308: struct timespec tv[2];
309:
310: /*
311: * If we don't have a download already in session, then the next
312: * one is coming in.
313: * Read either the stop (phase) signal from the sender or block
314: * metadata, in which case we open our file and wait for data.
315: */
316:
1.4 deraadt 317: if (p->state == DOWNLOAD_READ_NEXT) {
1.3 deraadt 318: if (!io_read_int(sess, p->fdin, &idx)) {
1.1 benno 319: ERRX1(sess, "io_read_int");
320: return -1;
321: } else if (idx >= 0 && (size_t)idx >= p->flsz) {
322: ERRX(sess, "index out of bounds");
323: return -1;
324: } else if (idx < 0) {
325: LOG3(sess, "downloader: phase complete");
326: return 0;
327: }
328:
329: /* Short-circuit: dry_run mode does nothing. */
330:
331: if (sess->opts->dry_run)
332: return 1;
333:
1.2 benno 334: /*
1.1 benno 335: * Now get our block information.
336: * This is all we'll need to reconstruct the file from
337: * the map, as block sizes are regular.
338: */
339:
340: download_reinit(sess, p, idx);
1.3 deraadt 341: if (!blk_send_ack(sess, p->fdin, &p->blk)) {
1.1 benno 342: ERRX1(sess, "blk_send_ack");
343: goto out;
344: }
345:
1.2 benno 346: /*
1.1 benno 347: * Next, we want to open the existing file for using as
348: * block input.
349: * We do this in a non-blocking way, so if the open
350: * succeeds, then we'll go reentrant til the file is
351: * readable and we can mmap() it.
352: * Set the file descriptor that we want to wait for.
353: */
354:
355: p->state = DOWNLOAD_READ_LOCAL;
356: f = &p->fl[idx];
1.4 deraadt 357: p->ofd = openat(p->rootfd, f->path, O_RDONLY | O_NONBLOCK, 0);
1.1 benno 358:
1.4 deraadt 359: if (p->ofd == -1 && errno != ENOENT) {
1.1 benno 360: ERR(sess, "%s: openat", f->path);
361: goto out;
1.4 deraadt 362: } else if (p->ofd != -1) {
1.1 benno 363: *ofd = p->ofd;
364: return 1;
365: }
366:
367: /* Fall-through: there's no file. */
368: }
369:
370: /*
371: * At this point, the server is sending us data and we want to
372: * hoover it up as quickly as possible or we'll deadlock.
373: * We want to be pulling off of f->fdin as quickly as possible,
374: * so perform as much buffering as we can.
375: */
376:
377: f = &p->fl[p->idx];
378:
379: /*
380: * Next in sequence: we have an open download session but
381: * haven't created our temporary file.
382: * This means that we've already opened (or tried to open) the
383: * original file in a nonblocking way, and we can map it.
384: */
385:
1.4 deraadt 386: if (p->state == DOWNLOAD_READ_LOCAL) {
387: assert(p->fname == NULL);
1.1 benno 388:
1.2 benno 389: /*
1.1 benno 390: * Try to fstat() the file descriptor if valid and make
391: * sure that we're still a regular file.
392: * Then, if it has non-zero size, mmap() it for hashing.
393: */
394:
1.4 deraadt 395: if (p->ofd != -1 &&
396: fstat(p->ofd, &st) == -1) {
1.1 benno 397: ERR(sess, "%s: fstat", f->path);
398: goto out;
1.4 deraadt 399: } else if (p->ofd != -1 && !S_ISREG(st.st_mode)) {
1.1 benno 400: WARNX(sess, "%s: not regular", f->path);
401: goto out;
402: }
403:
1.4 deraadt 404: if (p->ofd != -1 && st.st_size > 0) {
1.1 benno 405: p->mapsz = st.st_size;
1.2 benno 406: p->map = mmap(NULL, p->mapsz,
1.1 benno 407: PROT_READ, MAP_SHARED, p->ofd, 0);
1.4 deraadt 408: if (p->map == MAP_FAILED) {
1.1 benno 409: ERR(sess, "%s: mmap", f->path);
410: goto out;
411: }
412: }
413:
414: /* Success either way: we don't need this. */
415:
416: *ofd = -1;
417:
1.2 benno 418: /*
1.1 benno 419: * Create the temporary file.
420: * Use a simple scheme of path/.FILE.RANDOM, where we
421: * fill in RANDOM with an arc4random number.
422: * The tricky part is getting into the directory if
423: * we're in recursive mode.
424: */
425:
426: hash = arc4random();
427: if (sess->opts->recursive &&
428: NULL != (cp = strrchr(f->path, '/'))) {
429: dirlen = cp - f->path;
430: if (asprintf(&p->fname, "%.*s/.%s.%" PRIu32,
431: (int)dirlen, f->path,
432: f->path + dirlen + 1, hash) < 0)
433: p->fname = NULL;
434: } else {
1.2 benno 435: if (asprintf(&p->fname, ".%s.%" PRIu32,
1.1 benno 436: f->path, hash) < 0)
437: p->fname = NULL;
438: }
1.4 deraadt 439: if (p->fname == NULL) {
1.1 benno 440: ERR(sess, "asprintf");
441: goto out;
442: }
443:
1.2 benno 444: /*
1.1 benno 445: * Inherit permissions from the source file if we're new
446: * or specifically told with -p.
447: */
448:
1.3 deraadt 449: if (!sess->opts->preserve_perms)
1.1 benno 450: perm = -1 == p->ofd ? f->st.mode : st.st_mode;
451: else
452: perm = f->st.mode;
453:
1.2 benno 454: p->fd = openat(p->rootfd, p->fname,
1.1 benno 455: O_APPEND|O_WRONLY|O_CREAT|O_EXCL, perm);
456:
1.4 deraadt 457: if (p->fd == -1) {
1.1 benno 458: ERR(sess, "%s: openat", p->fname);
459: goto out;
460: }
461:
1.2 benno 462: /*
1.1 benno 463: * FIXME: we can technically wait until the temporary
464: * file is writable, but since it's guaranteed to be
465: * empty, I don't think this is a terribly expensive
466: * operation as it doesn't involve reading the file into
467: * memory beforehand.
468: */
469:
470: LOG3(sess, "%s: temporary: %s", f->path, p->fname);
471: p->state = DOWNLOAD_READ_REMOTE;
472: return 1;
473: }
474:
475: /*
476: * This matches the sequence in blk_flush().
477: * If we've gotten here, then we have a possibly-open map file
478: * (not for new files) and our temporary file is writable.
479: * We read the size/token, then optionally the data.
480: * The size >0 for reading data, 0 for no more data, and <0 for
481: * a token indicator.
482: */
483:
1.4 deraadt 484: assert(p->state == DOWNLOAD_READ_REMOTE);
485: assert(p->fname != NULL);
486: assert(p->fd != -1);
487: assert(p->fdin != -1);
1.1 benno 488:
1.3 deraadt 489: if (!io_read_int(sess, p->fdin, &rawtok)) {
1.1 benno 490: ERRX1(sess, "io_read_int");
491: goto out;
1.2 benno 492: }
1.1 benno 493:
494: if (rawtok > 0) {
495: sz = rawtok;
1.4 deraadt 496: if ((buf = malloc(sz)) == NULL) {
1.1 benno 497: ERR(sess, "realloc");
498: goto out;
499: }
1.3 deraadt 500: if (!io_read_buf(sess, p->fdin, buf, sz)) {
1.1 benno 501: ERRX1(sess, "io_read_int");
502: goto out;
1.3 deraadt 503: } else if (!buf_copy(sess, buf, sz, p)) {
1.1 benno 504: ERRX1(sess, "buf_copy");
505: goto out;
506: }
507: p->total += sz;
508: p->downloaded += sz;
509: LOG4(sess, "%s: received %zu B block", p->fname, sz);
510: MD4_Update(&p->ctx, buf, sz);
511: free(buf);
512: return 1;
513: } else if (rawtok < 0) {
514: tok = -rawtok - 1;
515: if (tok >= p->blk.blksz) {
516: ERRX(sess, "%s: token not in block "
1.2 benno 517: "set: %zu (have %zu blocks)",
1.1 benno 518: p->fname, tok, p->blk.blksz);
519: goto out;
520: }
521: sz = tok == p->blk.blksz - 1 ? p->blk.rem : p->blk.len;
522: assert(sz);
1.4 deraadt 523: assert(p->map != MAP_FAILED);
1.1 benno 524: buf = p->map + (tok * p->blk.len);
525:
526: /*
527: * Now we read from our block.
528: * We should only be at this point if we have a
529: * block to read from, i.e., if we were able to
530: * map our origin file and create a block
531: * profile from it.
532: */
533:
1.4 deraadt 534: assert(p->map != MAP_FAILED);
1.3 deraadt 535: if (!buf_copy(sess, buf, sz, p)) {
1.1 benno 536: ERRX1(sess, "buf_copy");
537: goto out;
538: }
539: p->total += sz;
540: LOG4(sess, "%s: copied %zu B", p->fname, sz);
541: MD4_Update(&p->ctx, buf, sz);
542: return 1;
543: }
544:
1.3 deraadt 545: if (!buf_copy(sess, NULL, 0, p)) {
1.1 benno 546: ERRX1(sess, "buf_copy");
547: goto out;
548: }
549:
1.4 deraadt 550: assert(rawtok == 0);
551: assert(p->obufsz == 0);
1.1 benno 552:
1.2 benno 553: /*
1.1 benno 554: * Make sure our resulting MD4 hashes match.
555: * FIXME: if the MD4 hashes don't match, then our file has
556: * changed out from under us.
557: * This should require us to re-run the sequence in another
558: * phase.
559: */
560:
561: MD4_Final(ourmd, &p->ctx);
562:
1.3 deraadt 563: if (!io_read_buf(sess, p->fdin, md, MD4_DIGEST_LENGTH)) {
1.1 benno 564: ERRX1(sess, "io_read_buf");
565: goto out;
566: } else if (memcmp(md, ourmd, MD4_DIGEST_LENGTH)) {
567: ERRX(sess, "%s: hash does not match", p->fname);
568: goto out;
1.5 ! benno 569: }
! 570:
! 571: if (sess->opts->preserve_gids) {
! 572: if (fchown(p->fd, -1, f->st.gid) == -1) {
! 573: if (errno != EPERM) {
! 574: ERR(sess, "%s: fchown", p->fname);
! 575: goto out;
! 576: }
! 577: WARNX(sess, "%s: gid not available to user: %u",
! 578: f->path, f->st.gid);
! 579: } else
! 580: LOG4(sess, "%s: updated gid", f->path);
1.1 benno 581: }
582:
583: /* Conditionally adjust file modification time. */
584:
585: if (sess->opts->preserve_times) {
586: tv[0].tv_sec = time(NULL);
587: tv[0].tv_nsec = 0;
588: tv[1].tv_sec = f->st.mtime;
589: tv[1].tv_nsec = 0;
1.4 deraadt 590: if (futimens(p->fd, tv) == -1) {
1.1 benno 591: ERR(sess, "%s: futimens", p->fname);
592: goto out;
593: }
594: LOG4(sess, "%s: updated date", f->path);
595: }
596:
597: /* Finally, rename the temporary to the real file. */
598:
1.4 deraadt 599: if (renameat(p->rootfd, p->fname, p->rootfd, f->path) == -1) {
1.1 benno 600: ERR(sess, "%s: renameat: %s", p->fname, f->path);
601: goto out;
602: }
603:
604: log_file(sess, p, f);
605: download_cleanup(p, 0);
606: return 1;
607: out:
608: download_cleanup(p, 1);
609: return -1;
610: }
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