xref: /openbsd-src/usr.bin/rsync/uploader.c (revision b0f539e9923c93d213bbde92bfd6b7a67cb6927c)
1 /*	$Id: uploader.c,v 1.22 2019/05/08 21:30:11 benno Exp $ */
2 /*
3  * Copyright (c) 2019 Kristaps Dzonsons <kristaps@bsd.lv>
4  * Copyright (c) 2019 Florian Obser <florian@openbsd.org>
5  *
6  * Permission to use, copy, modify, and distribute this software for any
7  * purpose with or without fee is hereby granted, provided that the above
8  * copyright notice and this permission notice appear in all copies.
9  *
10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17  */
18 #include <sys/mman.h>
19 #include <sys/stat.h>
20 
21 #include <assert.h>
22 #include <errno.h>
23 #include <fcntl.h>
24 #include <inttypes.h>
25 #include <math.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 
34 enum	uploadst {
35 	UPLOAD_FIND_NEXT = 0, /* find next to upload to sender */
36 	UPLOAD_WRITE_LOCAL, /* wait to write to sender */
37 	UPLOAD_READ_LOCAL, /* wait to read from local file */
38 	UPLOAD_FINISHED /* nothing more to do in phase */
39 };
40 
41 /*
42  * Used to keep track of data flowing from the receiver to the sender.
43  * This is managed by the receiver process.
44  */
45 struct	upload {
46 	enum uploadst	    state;
47 	char		   *buf; /* if not NULL, pending upload */
48 	size_t		    bufsz; /* size of buf */
49 	size_t		    bufmax; /* maximum size of buf */
50 	size_t		    bufpos; /* position in buf */
51 	size_t		    idx; /* current transfer index */
52 	mode_t		    oumask; /* umask for creating files */
53 	char		   *root; /* destination directory path */
54 	int		    rootfd; /* destination directory */
55 	size_t		    csumlen; /* checksum length */
56 	int		    fdout; /* write descriptor to sender */
57 	const struct flist *fl; /* file list */
58 	size_t		    flsz; /* size of file list */
59 	int		   *newdir; /* non-zero if mkdir'd */
60 };
61 
62 /*
63  * Log a directory by emitting the file and a trailing slash, just to
64  * show the operator that we're a directory.
65  */
66 static void
67 log_dir(struct sess *sess, const struct flist *f)
68 {
69 	size_t	 sz;
70 
71 	if (sess->opts->server)
72 		return;
73 	sz = strlen(f->path);
74 	assert(sz > 0);
75 	LOG1("%s%s", f->path, (f->path[sz - 1] == '/') ? "" : "/");
76 }
77 
78 /*
79  * Log a link by emitting the file and the target, just to show the
80  * operator that we're a link.
81  */
82 static void
83 log_link(struct sess *sess, const struct flist *f)
84 {
85 
86 	if (!sess->opts->server)
87 		LOG1("%s -> %s", f->path, f->link);
88 }
89 
90 /*
91  * Simply log the filename.
92  */
93 static void
94 log_file(struct sess *sess, const struct flist *f)
95 {
96 
97 	if (!sess->opts->server)
98 		LOG1("%s", f->path);
99 }
100 
101 /*
102  * Prepare the overall block set's metadata.
103  * We always have at least one block.
104  * The block size is an important part of the algorithm.
105  * I use the same heuristic as the reference rsync, but implemented in a
106  * bit more of a straightforward way.
107  * In general, the individual block length is the rounded square root of
108  * the total file size.
109  * The minimum block length is 700.
110  */
111 static void
112 init_blkset(struct blkset *p, off_t sz)
113 {
114 	double	 v;
115 
116 	if (sz >= (BLOCK_SIZE_MIN * BLOCK_SIZE_MIN)) {
117 		/* Simple rounded-up integer square root. */
118 
119 		v = sqrt(sz);
120 		p->len = ceil(v);
121 
122 		/*
123 		 * Always be a multiple of eight.
124 		 * There's no reason to do this, but rsync does.
125 		 */
126 
127 		if ((p->len % 8) > 0)
128 			p->len += 8 - (p->len % 8);
129 	} else
130 		p->len = BLOCK_SIZE_MIN;
131 
132 	p->size = sz;
133 	if ((p->blksz = sz / p->len) == 0)
134 		p->rem = sz;
135 	else
136 		p->rem = sz % p->len;
137 
138 	/* If we have a remainder, then we need an extra block. */
139 
140 	if (p->rem)
141 		p->blksz++;
142 }
143 
144 /*
145  * For each block, prepare the block's metadata.
146  * We use the mapped "map" file to set our checksums.
147  */
148 static void
149 init_blk(struct blk *p, const struct blkset *set, off_t offs,
150 	size_t idx, const void *map, const struct sess *sess)
151 {
152 
153 	assert(map != MAP_FAILED);
154 
155 	/* Block length inherits for all but the last. */
156 
157 	p->idx = idx;
158 	p->len = idx < set->blksz - 1 ? set->len : set->rem;
159 	p->offs = offs;
160 
161 	p->chksum_short = hash_fast(map + offs, p->len);
162 	hash_slow(map + offs, p->len, p->chksum_long, sess);
163 }
164 
165 /*
166  * Handle a symbolic link.
167  * If we encounter directories existing in the symbolic link's place,
168  * then try to unlink the directory.
169  * Otherwise, simply overwrite with the symbolic link by renaming.
170  * Return <0 on failure 0 on success.
171  */
172 static int
173 pre_link(struct upload *p, struct sess *sess)
174 {
175 	struct stat		 st;
176 	const struct flist	*f;
177 	int			 rc, newlink = 0, updatelink = 0;
178 	char			*b, *temp = NULL;
179 
180 	f = &p->fl[p->idx];
181 	assert(S_ISLNK(f->st.mode));
182 
183 	if (!sess->opts->preserve_links) {
184 		WARNX("%s: ignoring symlink", f->path);
185 		return 0;
186 	} else if (sess->opts->dry_run) {
187 		log_link(sess, f);
188 		return 0;
189 	}
190 
191 	/*
192 	 * See if the symlink already exists.
193 	 * If it's a directory, then try to unlink the directory prior
194 	 * to overwriting with a symbolic link.
195 	 * If it's a non-directory, we just overwrite it.
196 	 */
197 
198 	assert(p->rootfd != -1);
199 	rc = fstatat(p->rootfd, f->path, &st, AT_SYMLINK_NOFOLLOW);
200 	if (rc != -1 && !S_ISLNK(st.st_mode)) {
201 		if (S_ISDIR(st.st_mode) &&
202 		    unlinkat(p->rootfd, f->path, AT_REMOVEDIR) == -1) {
203 			ERR("%s: unlinkat", f->path);
204 			return -1;
205 		}
206 		rc = -1;
207 	} else if (rc == -1 && errno != ENOENT) {
208 		ERR("%s: fstatat", f->path);
209 		return -1;
210 	}
211 
212 	/*
213 	 * If the symbolic link already exists, then make sure that it
214 	 * points to the correct place.
215 	 */
216 
217 	if (rc != -1) {
218 		b = symlinkat_read(p->rootfd, f->path);
219 		if (b == NULL) {
220 			ERRX1("symlinkat_read");
221 			return -1;
222 		}
223 		if (strcmp(f->link, b)) {
224 			free(b);
225 			b = NULL;
226 			LOG3("%s: updating symlink: %s", f->path, f->link);
227 			updatelink = 1;
228 		}
229 		free(b);
230 		b = NULL;
231 	}
232 
233 	/*
234 	 * Create the temporary file as a symbolic link, then rename the
235 	 * temporary file as the real one, overwriting anything there.
236 	 */
237 
238 	if (rc == -1 || updatelink) {
239 		LOG3("%s: creating symlink: %s", f->path, f->link);
240 		if (mktemplate(&temp, f->path, sess->opts->recursive) == -1) {
241 			ERRX1("mktemplate");
242 			return -1;
243 		}
244 		if (mkstemplinkat(f->link, p->rootfd, temp) == NULL) {
245 			ERR("mkstemplinkat");
246 			free(temp);
247 			return -1;
248 		}
249 		newlink = 1;
250 	}
251 
252 	rsync_set_metadata_at(sess, newlink,
253 		p->rootfd, f, newlink ? temp : f->path);
254 
255 	if (newlink) {
256 		if (renameat(p->rootfd, temp, p->rootfd, f->path) == -1) {
257 			ERR("%s: renameat %s", temp, f->path);
258 			(void)unlinkat(p->rootfd, temp, 0);
259 			free(temp);
260 			return -1;
261 		}
262 		free(temp);
263 	}
264 
265 	log_link(sess, f);
266 	return 0;
267 }
268 
269 /*
270  * See pre_link(), but for devices.
271  * FIXME: this is very similar to the other pre_xxx() functions.
272  * Return <0 on failure 0 on success.
273  */
274 static int
275 pre_dev(struct upload *p, struct sess *sess)
276 {
277 	struct stat		 st;
278 	const struct flist	*f;
279 	int			 rc, newdev = 0, updatedev = 0;
280 	char			*temp = NULL;
281 
282 	f = &p->fl[p->idx];
283 	assert(S_ISBLK(f->st.mode) || S_ISCHR(f->st.mode));
284 
285 	if (!sess->opts->devices || getuid() != 0) {
286 		WARNX("skipping non-regular file %s", f->path);
287 		return 0;
288 	} else if (sess->opts->dry_run) {
289 		log_file(sess, f);
290 		return 0;
291 	}
292 
293 	/*
294 	 * See if the dev already exists.
295 	 * If a non-device exists in its place, we'll replace that.
296 	 * If it replaces a directory, remove the directory first.
297 	 */
298 
299 	assert(p->rootfd != -1);
300 	rc = fstatat(p->rootfd, f->path, &st, AT_SYMLINK_NOFOLLOW);
301 
302 	if (rc != -1 && !(S_ISBLK(st.st_mode) || S_ISCHR(st.st_mode))) {
303 		if (S_ISDIR(st.st_mode) &&
304 		    unlinkat(p->rootfd, f->path, AT_REMOVEDIR) == -1) {
305 			ERR("%s: unlinkat", f->path);
306 			return -1;
307 		}
308 		rc = -1;
309 	} else if (rc == -1 && errno != ENOENT) {
310 		ERR("%s: fstatat", f->path);
311 		return -1;
312 	}
313 
314 	/* Make sure existing device is of the correct type. */
315 
316 	if (rc != -1) {
317 		if ((f->st.mode & (S_IFCHR|S_IFBLK)) !=
318 		    (st.st_mode & (S_IFCHR|S_IFBLK)) ||
319 		    f->st.rdev != st.st_rdev) {
320 			LOG3("%s: updating device", f->path);
321 			updatedev = 1;
322 		}
323 	}
324 
325 	if (rc == -1 || updatedev) {
326 		newdev = 1;
327 		if (mktemplate(&temp, f->path, sess->opts->recursive) == -1) {
328 			ERRX1("mktemplate");
329 			return -1;
330 		}
331 		if (mkstempnodat(p->rootfd, temp,
332 		    f->st.mode & (S_IFCHR|S_IFBLK), f->st.rdev) == NULL) {
333 			ERR("mkstempnodat");
334 			free(temp);
335 			return -1;
336 		}
337 	}
338 
339 	rsync_set_metadata_at(sess, newdev,
340 	    p->rootfd, f, newdev ? temp : f->path);
341 
342 	if (newdev) {
343 		if (renameat(p->rootfd, temp, p->rootfd, f->path) == -1) {
344 			ERR("%s: renameat %s", temp, f->path);
345 			(void)unlinkat(p->rootfd, temp, 0);
346 			free(temp);
347 			return -1;
348 		}
349 		free(temp);
350 	}
351 
352 	log_file(sess, f);
353 	return 0;
354 }
355 
356 /*
357  * See pre_link(), but for FIFOs.
358  * FIXME: this is very similar to the other pre_xxx() functions.
359  * Return <0 on failure 0 on success.
360  */
361 static int
362 pre_fifo(struct upload *p, struct sess *sess)
363 {
364 	struct stat		 st;
365 	const struct flist	*f;
366 	int			 rc, newfifo = 0;
367 	char			*temp = NULL;
368 
369 	f = &p->fl[p->idx];
370 	assert(S_ISFIFO(f->st.mode));
371 
372 	if (!sess->opts->specials) {
373 		WARNX("skipping non-regular file %s", f->path);
374 		return 0;
375 	} else if (sess->opts->dry_run) {
376 		log_file(sess, f);
377 		return 0;
378 	}
379 
380 	/*
381 	 * See if the fifo already exists.
382 	 * If it exists as a non-FIFO, unlink it (if a directory) then
383 	 * mark it from replacement.
384 	 */
385 
386 	assert(p->rootfd != -1);
387 	rc = fstatat(p->rootfd, f->path, &st, AT_SYMLINK_NOFOLLOW);
388 
389 	if (rc != -1 && !S_ISFIFO(st.st_mode)) {
390 		if (S_ISDIR(st.st_mode) &&
391 		    unlinkat(p->rootfd, f->path, AT_REMOVEDIR) == -1) {
392 			ERR("%s: unlinkat", f->path);
393 			return -1;
394 		}
395 		rc = -1;
396 	} else if (rc == -1 && errno != ENOENT) {
397 		ERR("%s: fstatat", f->path);
398 		return -1;
399 	}
400 
401 	if (rc == -1) {
402 		newfifo = 1;
403 		if (mktemplate(&temp, f->path, sess->opts->recursive) == -1) {
404 			ERRX1("mktemplate");
405 			return -1;
406 		}
407 		if (mkstempfifoat(p->rootfd, temp) == NULL) {
408 			ERR("mkstempfifoat");
409 			free(temp);
410 			return -1;
411 		}
412 	}
413 
414 	rsync_set_metadata_at(sess, newfifo,
415 		p->rootfd, f, newfifo ? temp : f->path);
416 
417 	if (newfifo) {
418 		if (renameat(p->rootfd, temp, p->rootfd, f->path) == -1) {
419 			ERR("%s: renameat %s", temp, f->path);
420 			(void)unlinkat(p->rootfd, temp, 0);
421 			free(temp);
422 			return -1;
423 		}
424 		free(temp);
425 	}
426 
427 	log_file(sess, f);
428 	return 0;
429 }
430 
431 /*
432  * See pre_link(), but for socket files.
433  * FIXME: this is very similar to the other pre_xxx() functions.
434  * Return <0 on failure 0 on success.
435  */
436 static int
437 pre_sock(struct upload *p, struct sess *sess)
438 {
439 	struct stat		 st;
440 	const struct flist	*f;
441 	int			 rc, newsock = 0;
442 	char			*temp = NULL;
443 
444 	f = &p->fl[p->idx];
445 	assert(S_ISSOCK(f->st.mode));
446 
447 	if (!sess->opts->specials) {
448 		WARNX("skipping non-regular file %s", f->path);
449 		return 0;
450 	} else if (sess->opts->dry_run) {
451 		log_file(sess, f);
452 		return 0;
453 	}
454 
455 	/*
456 	 * See if the fifo already exists.
457 	 * If it exists as a non-FIFO, unlink it (if a directory) then
458 	 * mark it from replacement.
459 	 */
460 
461 	assert(p->rootfd != -1);
462 	rc = fstatat(p->rootfd, f->path, &st, AT_SYMLINK_NOFOLLOW);
463 
464 	if (rc != -1 && !S_ISSOCK(st.st_mode)) {
465 		if (S_ISDIR(st.st_mode) &&
466 		    unlinkat(p->rootfd, f->path, AT_REMOVEDIR) == -1) {
467 			ERR("%s: unlinkat", f->path);
468 			return -1;
469 		}
470 		rc = -1;
471 	} else if (rc == -1 && errno != ENOENT) {
472 		ERR("%s: fstatat", f->path);
473 		return -1;
474 	}
475 
476 	if (rc == -1) {
477 		newsock = 1;
478 		if (mktemplate(&temp, f->path, sess->opts->recursive) == -1) {
479 			ERRX1("mktemplate");
480 			return -1;
481 		}
482 		if (mkstempsock(p->root, temp) == NULL) {
483 			ERR("mkstempsock");
484 			free(temp);
485 			return -1;
486 		}
487 	}
488 
489 	rsync_set_metadata_at(sess, newsock,
490 		p->rootfd, f, newsock ? temp : f->path);
491 
492 	if (newsock) {
493 		if (renameat(p->rootfd, temp, p->rootfd, f->path) == -1) {
494 			ERR("%s: renameat %s", temp, f->path);
495 			(void)unlinkat(p->rootfd, temp, 0);
496 			free(temp);
497 			return -1;
498 		}
499 		free(temp);
500 	}
501 
502 	log_file(sess, f);
503 	return 0;
504 }
505 
506 /*
507  * If not found, create the destination directory in prefix order.
508  * Create directories using the existing umask.
509  * Return <0 on failure 0 on success.
510  */
511 static int
512 pre_dir(const struct upload *p, struct sess *sess)
513 {
514 	struct stat	 st;
515 	int		 rc;
516 	const struct flist *f;
517 
518 	f = &p->fl[p->idx];
519 	assert(S_ISDIR(f->st.mode));
520 
521 	if (!sess->opts->recursive) {
522 		WARNX("%s: ignoring directory", f->path);
523 		return 0;
524 	} else if (sess->opts->dry_run) {
525 		log_dir(sess, f);
526 		return 0;
527 	}
528 
529 	assert(p->rootfd != -1);
530 	rc = fstatat(p->rootfd, f->path, &st, AT_SYMLINK_NOFOLLOW);
531 
532 	if (rc == -1 && errno != ENOENT) {
533 		ERR("%s: fstatat", f->path);
534 		return -1;
535 	} else if (rc != -1 && !S_ISDIR(st.st_mode)) {
536 		ERRX("%s: not a directory", f->path);
537 		return -1;
538 	} else if (rc != -1) {
539 		/*
540 		 * FIXME: we should fchmod the permissions here as well,
541 		 * as we may locally have shut down writing into the
542 		 * directory and that doesn't work.
543 		 */
544 		LOG3("%s: updating directory", f->path);
545 		return 0;
546 	}
547 
548 	/*
549 	 * We want to make the directory with default permissions (using
550 	 * our old umask, which we've since unset), then adjust
551 	 * permissions (assuming preserve_perms or new) afterward in
552 	 * case it's u-w or something.
553 	 */
554 
555 	LOG3("%s: creating directory", f->path);
556 	if (mkdirat(p->rootfd, f->path, 0777 & ~p->oumask) == -1) {
557 		ERR("%s: mkdirat", f->path);
558 		return -1;
559 	}
560 
561 	p->newdir[p->idx] = 1;
562 	log_dir(sess, f);
563 	return 0;
564 }
565 
566 /*
567  * Process the directory time and mode for "idx" in the file list.
568  * Returns zero on failure, non-zero on success.
569  */
570 static int
571 post_dir(struct sess *sess, const struct upload *u, size_t idx)
572 {
573 	struct timespec	 tv[2];
574 	int		 rc;
575 	struct stat	 st;
576 	const struct flist *f;
577 
578 	f = &u->fl[idx];
579 	assert(S_ISDIR(f->st.mode));
580 
581 	/* We already warned about the directory in pre_process_dir(). */
582 
583 	if (!sess->opts->recursive)
584 		return 1;
585 	else if (sess->opts->dry_run)
586 		return 1;
587 
588 	if (fstatat(u->rootfd, f->path, &st, AT_SYMLINK_NOFOLLOW) == -1) {
589 		ERR("%s: fstatat", f->path);
590 		return 0;
591 	} else if (!S_ISDIR(st.st_mode)) {
592 		WARNX("%s: not a directory", f->path);
593 		return 0;
594 	}
595 
596 	/*
597 	 * Update the modification time if we're a new directory *or* if
598 	 * we're preserving times and the time has changed.
599 	 * FIXME: run rsync_set_metadata()?
600 	 */
601 
602 	if (u->newdir[idx] ||
603 	    (sess->opts->preserve_times &&
604 	     st.st_mtime != f->st.mtime)) {
605 		tv[0].tv_sec = time(NULL);
606 		tv[0].tv_nsec = 0;
607 		tv[1].tv_sec = f->st.mtime;
608 		tv[1].tv_nsec = 0;
609 		rc = utimensat(u->rootfd, f->path, tv, 0);
610 		if (rc == -1) {
611 			ERR("%s: utimensat", f->path);
612 			return 0;
613 		}
614 		LOG4("%s: updated date", f->path);
615 	}
616 
617 	/*
618 	 * Update the mode if we're a new directory *or* if we're
619 	 * preserving modes and it has changed.
620 	 */
621 
622 	if (u->newdir[idx] ||
623 	    (sess->opts->preserve_perms && st.st_mode != f->st.mode)) {
624 		rc = fchmodat(u->rootfd, f->path, f->st.mode, 0);
625 		if (rc == -1) {
626 			ERR("%s: fchmodat", f->path);
627 			return 0;
628 		}
629 		LOG4("%s: updated mode", f->path);
630 	}
631 
632 	return 1;
633 }
634 
635 /*
636  * Try to open the file at the current index.
637  * If the file does not exist, returns with success.
638  * Return <0 on failure, 0 on success w/nothing to be done, >0 on
639  * success and the file needs attention.
640  */
641 static int
642 pre_file(const struct upload *p, int *filefd, struct sess *sess)
643 {
644 	const struct flist *f;
645 
646 	f = &p->fl[p->idx];
647 	assert(S_ISREG(f->st.mode));
648 
649 	if (sess->opts->dry_run) {
650 		log_file(sess, f);
651 		if (!io_write_int(sess, p->fdout, p->idx)) {
652 			ERRX1("io_write_int");
653 			return -1;
654 		}
655 		return 0;
656 	}
657 
658 	/*
659 	 * For non dry-run cases, we'll write the acknowledgement later
660 	 * in the rsync_uploader() function because we need to wait for
661 	 * the open() call to complete.
662 	 * If the call to openat() fails with ENOENT, there's a
663 	 * fast-path between here and the write function, so we won't do
664 	 * any blocking between now and then.
665 	 */
666 
667 	*filefd = openat(p->rootfd, f->path,
668 		O_RDONLY | O_NOFOLLOW | O_NONBLOCK, 0);
669 	if (*filefd != -1 || errno == ENOENT)
670 		return 1;
671 	ERR("%s: openat", f->path);
672 	return -1;
673 }
674 
675 /*
676  * Allocate an uploader object in the correct state to start.
677  * Returns NULL on failure or the pointer otherwise.
678  * On success, upload_free() must be called with the allocated pointer.
679  */
680 struct upload *
681 upload_alloc(const char *root, int rootfd, int fdout,
682 	size_t clen, const struct flist *fl, size_t flsz, mode_t msk)
683 {
684 	struct upload	*p;
685 
686 	if ((p = calloc(1, sizeof(struct upload))) == NULL) {
687 		ERR("calloc");
688 		return NULL;
689 	}
690 
691 	p->state = UPLOAD_FIND_NEXT;
692 	p->oumask = msk;
693 	p->root = strdup(root);
694 	if (p->root == NULL) {
695 		ERR("strdup");
696 		free(p);
697 		return NULL;
698 	}
699 	p->rootfd = rootfd;
700 	p->csumlen = clen;
701 	p->fdout = fdout;
702 	p->fl = fl;
703 	p->flsz = flsz;
704 	p->newdir = calloc(flsz, sizeof(int));
705 	if (p->newdir == NULL) {
706 		ERR("calloc");
707 		free(p->root);
708 		free(p);
709 		return NULL;
710 	}
711 	return p;
712 }
713 
714 /*
715  * Perform all cleanups and free.
716  * Passing a NULL to this function is ok.
717  */
718 void
719 upload_free(struct upload *p)
720 {
721 
722 	if (p == NULL)
723 		return;
724 	free(p->root);
725 	free(p->newdir);
726 	free(p->buf);
727 	free(p);
728 }
729 
730 /*
731  * Iterates through all available files and conditionally gets the file
732  * ready for processing to check whether it's up to date.
733  * If not up to date or empty, sends file information to the sender.
734  * If returns 0, we've processed all files there are to process.
735  * If returns >0, we're waiting for POLLIN or POLLOUT data.
736  * Otherwise returns <0, which is an error.
737  */
738 int
739 rsync_uploader(struct upload *u, int *fileinfd,
740 	struct sess *sess, int *fileoutfd)
741 {
742 	struct blkset	    blk;
743 	struct stat	    st;
744 	void		   *map, *bufp;
745 	size_t		    i, mapsz, pos, sz;
746 	off_t		    offs;
747 	int		    c;
748 	const struct flist *f;
749 
750 	/* This should never get called. */
751 
752 	assert(u->state != UPLOAD_FINISHED);
753 
754 	/*
755 	 * If we have an upload in progress, then keep writing until the
756 	 * buffer has been fully written.
757 	 * We must only have the output file descriptor working and also
758 	 * have a valid buffer to write.
759 	 */
760 
761 	if (u->state == UPLOAD_WRITE_LOCAL) {
762 		assert(u->buf != NULL);
763 		assert(*fileoutfd != -1);
764 		assert(*fileinfd == -1);
765 
766 		/*
767 		 * Unfortunately, we need to chunk these: if we're
768 		 * the server side of things, then we're multiplexing
769 		 * output and need to wrap this in chunks.
770 		 * This is a major deficiency of rsync.
771 		 * FIXME: add a "fast-path" mode that simply dumps out
772 		 * the buffer non-blocking if we're not mplexing.
773 		 */
774 
775 		if (u->bufpos < u->bufsz) {
776 			sz = MAX_CHUNK < (u->bufsz - u->bufpos) ?
777 				MAX_CHUNK : (u->bufsz - u->bufpos);
778 			c = io_write_buf(sess, u->fdout,
779 				u->buf + u->bufpos, sz);
780 			if (c == 0) {
781 				ERRX1("io_write_nonblocking");
782 				return -1;
783 			}
784 			u->bufpos += sz;
785 			if (u->bufpos < u->bufsz)
786 				return 1;
787 		}
788 
789 		/*
790 		 * Let the UPLOAD_FIND_NEXT state handle things if we
791 		 * finish, as we'll need to write a POLLOUT message and
792 		 * not have a writable descriptor yet.
793 		 */
794 
795 		u->state = UPLOAD_FIND_NEXT;
796 		u->idx++;
797 		return 1;
798 	}
799 
800 	/*
801 	 * If we invoke the uploader without a file currently open, then
802 	 * we iterate through til the next available regular file and
803 	 * start the opening process.
804 	 * This means we must have the output file descriptor working.
805 	 */
806 
807 	if (u->state == UPLOAD_FIND_NEXT) {
808 		assert(*fileinfd == -1);
809 		assert(*fileoutfd != -1);
810 
811 		for ( ; u->idx < u->flsz; u->idx++) {
812 			if (S_ISDIR(u->fl[u->idx].st.mode))
813 				c = pre_dir(u, sess);
814 			else if (S_ISLNK(u->fl[u->idx].st.mode))
815 				c = pre_link(u, sess);
816 			else if (S_ISREG(u->fl[u->idx].st.mode))
817 				c = pre_file(u, fileinfd, sess);
818 			else if (S_ISBLK(u->fl[u->idx].st.mode) ||
819 			    S_ISCHR(u->fl[u->idx].st.mode))
820 				c = pre_dev(u, sess);
821 			else if (S_ISFIFO(u->fl[u->idx].st.mode))
822 				c = pre_fifo(u, sess);
823 			else if (S_ISSOCK(u->fl[u->idx].st.mode))
824 				c = pre_sock(u, sess);
825 			else
826 				c = 0;
827 
828 			if (c < 0)
829 				return -1;
830 			else if (c > 0)
831 				break;
832 		}
833 
834 		/*
835 		 * Whether we've finished writing files or not, we
836 		 * disable polling on the output channel.
837 		 */
838 
839 		*fileoutfd = -1;
840 		if (u->idx == u->flsz) {
841 			assert(*fileinfd == -1);
842 			if (!io_write_int(sess, u->fdout, -1)) {
843 				ERRX1("io_write_int");
844 				return -1;
845 			}
846 			u->state = UPLOAD_FINISHED;
847 			LOG4("uploader: finished");
848 			return 0;
849 		}
850 
851 		/* Go back to the event loop, if necessary. */
852 
853 		u->state = (*fileinfd == -1) ?
854 			UPLOAD_WRITE_LOCAL : UPLOAD_READ_LOCAL;
855 		if (u->state == UPLOAD_READ_LOCAL)
856 			return 1;
857 	}
858 
859 	/*
860 	 * If an input file is open, stat it and see if it's already up
861 	 * to date, in which case close it and go to the next one.
862 	 * Either way, we don't have a write channel open.
863 	 */
864 
865 	if (u->state == UPLOAD_READ_LOCAL) {
866 		assert(*fileinfd != -1);
867 		assert(*fileoutfd == -1);
868 		f = &u->fl[u->idx];
869 
870 		if (fstat(*fileinfd, &st) == -1) {
871 			ERR("%s: fstat", f->path);
872 			close(*fileinfd);
873 			*fileinfd = -1;
874 			return -1;
875 		} else if (!S_ISREG(st.st_mode)) {
876 			ERRX("%s: not regular", f->path);
877 			close(*fileinfd);
878 			*fileinfd = -1;
879 			return -1;
880 		}
881 
882 		if (st.st_size == f->st.size &&
883 		    st.st_mtime == f->st.mtime) {
884 			LOG3("%s: skipping: up to date", f->path);
885 			if (!rsync_set_metadata
886 			    (sess, 0, *fileinfd, f, f->path)) {
887 				ERRX1("rsync_set_metadata");
888 				close(*fileinfd);
889 				*fileinfd = -1;
890 				return -1;
891 			}
892 			close(*fileinfd);
893 			*fileinfd = -1;
894 			*fileoutfd = u->fdout;
895 			u->state = UPLOAD_FIND_NEXT;
896 			u->idx++;
897 			return 1;
898 		}
899 
900 		/* Fallthrough... */
901 
902 		u->state = UPLOAD_WRITE_LOCAL;
903 	}
904 
905 	/* Initialies our blocks. */
906 
907 	assert(u->state == UPLOAD_WRITE_LOCAL);
908 	memset(&blk, 0, sizeof(struct blkset));
909 	blk.csum = u->csumlen;
910 
911 	if (*fileinfd != -1 && st.st_size > 0) {
912 		mapsz = st.st_size;
913 		map = mmap(NULL, mapsz, PROT_READ, MAP_SHARED, *fileinfd, 0);
914 		if (map == MAP_FAILED) {
915 			ERR("%s: mmap", u->fl[u->idx].path);
916 			close(*fileinfd);
917 			*fileinfd = -1;
918 			return -1;
919 		}
920 
921 		init_blkset(&blk, st.st_size);
922 		assert(blk.blksz);
923 
924 		blk.blks = calloc(blk.blksz, sizeof(struct blk));
925 		if (blk.blks == NULL) {
926 			ERR("calloc");
927 			munmap(map, mapsz);
928 			close(*fileinfd);
929 			*fileinfd = -1;
930 			return -1;
931 		}
932 
933 		offs = 0;
934 		for (i = 0; i < blk.blksz; i++) {
935 			init_blk(&blk.blks[i],
936 				&blk, offs, i, map, sess);
937 			offs += blk.len;
938 		}
939 
940 		munmap(map, mapsz);
941 		close(*fileinfd);
942 		*fileinfd = -1;
943 		LOG3("%s: mapped %jd B with %zu blocks",
944 		    u->fl[u->idx].path, (intmax_t)blk.size,
945 		    blk.blksz);
946 	} else {
947 		if (*fileinfd != -1) {
948 			close(*fileinfd);
949 			*fileinfd = -1;
950 		}
951 		blk.len = MAX_CHUNK; /* Doesn't matter. */
952 		LOG3("%s: not mapped", u->fl[u->idx].path);
953 	}
954 
955 	assert(*fileinfd == -1);
956 
957 	/* Make sure the block metadata buffer is big enough. */
958 
959 	u->bufsz =
960 	     sizeof(int32_t) + /* identifier */
961 	     sizeof(int32_t) + /* block count */
962 	     sizeof(int32_t) + /* block length */
963 	     sizeof(int32_t) + /* checksum length */
964 	     sizeof(int32_t) + /* block remainder */
965 	     blk.blksz *
966 	     (sizeof(int32_t) + /* short checksum */
967 	      blk.csum); /* long checksum */
968 
969 	if (u->bufsz > u->bufmax) {
970 		if ((bufp = realloc(u->buf, u->bufsz)) == NULL) {
971 			ERR("realloc");
972 			return -1;
973 		}
974 		u->buf = bufp;
975 		u->bufmax = u->bufsz;
976 	}
977 
978 	u->bufpos = pos = 0;
979 	io_buffer_int(u->buf, &pos, u->bufsz, u->idx);
980 	io_buffer_int(u->buf, &pos, u->bufsz, blk.blksz);
981 	io_buffer_int(u->buf, &pos, u->bufsz, blk.len);
982 	io_buffer_int(u->buf, &pos, u->bufsz, blk.csum);
983 	io_buffer_int(u->buf, &pos, u->bufsz, blk.rem);
984 	for (i = 0; i < blk.blksz; i++) {
985 		io_buffer_int(u->buf, &pos, u->bufsz,
986 			blk.blks[i].chksum_short);
987 		io_buffer_buf(u->buf, &pos, u->bufsz,
988 			blk.blks[i].chksum_long, blk.csum);
989 	}
990 	assert(pos == u->bufsz);
991 
992 	/* Reenable the output poller and clean up. */
993 
994 	*fileoutfd = u->fdout;
995 	free(blk.blks);
996 	return 1;
997 }
998 
999 /*
1000  * Fix up the directory permissions and times post-order.
1001  * We can't fix up directory permissions in place because the server may
1002  * want us to have overly-tight permissions---say, those that don't
1003  * allow writing into the directory.
1004  * We also need to do our directory times post-order because making
1005  * files within the directory will change modification times.
1006  * Returns zero on failure, non-zero on success.
1007  */
1008 int
1009 rsync_uploader_tail(struct upload *u, struct sess *sess)
1010 {
1011 	size_t	 i;
1012 
1013 
1014 	if (!sess->opts->preserve_times &&
1015 	    !sess->opts->preserve_perms)
1016 		return 1;
1017 
1018 	LOG2("fixing up directory times and permissions");
1019 
1020 	for (i = 0; i < u->flsz; i++)
1021 		if (S_ISDIR(u->fl[i].st.mode))
1022 			if (!post_dir(sess, u, i))
1023 				return 0;
1024 
1025 	return 1;
1026 }
1027