xref: /freebsd/usr.sbin/makefs/mtree.c (revision c6ec7d31830ab1c80edae95ad5e4b9dba10c47ac)
1 /*-
2  * Copyright (c) 2011 Marcel Moolenaar
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17  * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24  */
25 
26 #include <sys/cdefs.h>
27 __FBSDID("$FreeBSD$");
28 
29 #include <sys/param.h>
30 #include <sys/queue.h>
31 #include <sys/sbuf.h>
32 #include <sys/stat.h>
33 #include <sys/types.h>
34 #include <assert.h>
35 #include <errno.h>
36 #include <fcntl.h>
37 #include <grp.h>
38 #include <inttypes.h>
39 #include <pwd.h>
40 #include <stdarg.h>
41 #include <stdbool.h>
42 #include <stddef.h>
43 #include <stdio.h>
44 #include <stdlib.h>
45 #include <string.h>
46 #include <strings.h>
47 #include <unistd.h>
48 
49 #include "makefs.h"
50 
51 #define	IS_DOT(nm)	((nm)[0] == '.' && (nm)[1] == '\0')
52 #define	IS_DOTDOT(nm)	((nm)[0] == '.' && (nm)[1] == '.' && (nm)[2] == '\0')
53 
54 struct mtree_fileinfo {
55 	SLIST_ENTRY(mtree_fileinfo) next;
56 	FILE *fp;
57 	const char *name;
58 	u_int line;
59 };
60 
61 /* Global state used while parsing. */
62 static SLIST_HEAD(, mtree_fileinfo) mtree_fileinfo =
63     SLIST_HEAD_INITIALIZER(mtree_fileinfo);
64 static fsnode *mtree_root;
65 static fsnode *mtree_current;
66 static fsnode mtree_global;
67 static fsinode mtree_global_inode;
68 static u_int errors, warnings;
69 
70 static void mtree_error(const char *, ...) __printflike(1, 2);
71 static void mtree_warning(const char *, ...) __printflike(1, 2);
72 
73 static int
74 mtree_file_push(const char *name, FILE *fp)
75 {
76 	struct mtree_fileinfo *fi;
77 
78 	fi = malloc(sizeof(*fi));
79 	if (fi == NULL)
80 		return (ENOMEM);
81 
82 	if (strcmp(name, "-") == 0)
83 		fi->name = strdup("(stdin)");
84 	else
85 		fi->name = strdup(name);
86 	if (fi->name == NULL) {
87 		free(fi);
88 		return (ENOMEM);
89 	}
90 
91 	fi->fp = fp;
92 	fi->line = 0;
93 
94 	SLIST_INSERT_HEAD(&mtree_fileinfo, fi, next);
95 	return (0);
96 }
97 
98 static void
99 mtree_print(const char *msgtype, const char *fmt, va_list ap)
100 {
101 	struct mtree_fileinfo *fi;
102 
103 	if (msgtype != NULL) {
104 		fi = SLIST_FIRST(&mtree_fileinfo);
105 		if (fi != NULL)
106 			fprintf(stderr, "%s:%u: ", fi->name, fi->line);
107 		fprintf(stderr, "%s: ", msgtype);
108 	}
109 	vfprintf(stderr, fmt, ap);
110 }
111 
112 static void
113 mtree_error(const char *fmt, ...)
114 {
115 	va_list ap;
116 
117 	va_start(ap, fmt);
118 	mtree_print("error", fmt, ap);
119 	va_end(ap);
120 
121 	errors++;
122 	fputc('\n', stderr);
123 }
124 
125 static void
126 mtree_warning(const char *fmt, ...)
127 {
128 	va_list ap;
129 
130 	va_start(ap, fmt);
131 	mtree_print("warning", fmt, ap);
132 	va_end(ap);
133 
134 	warnings++;
135 	fputc('\n', stderr);
136 }
137 
138 #ifndef MAKEFS_MAX_TREE_DEPTH
139 # define MAKEFS_MAX_TREE_DEPTH (MAXPATHLEN/2)
140 #endif
141 
142 /* construct path to node->name */
143 static char *
144 mtree_file_path(fsnode *node)
145 {
146 	fsnode *pnode;
147 	struct sbuf *sb;
148 	char *res, *rp[MAKEFS_MAX_TREE_DEPTH];
149 	int depth;
150 
151 	depth = 0;
152 	rp[depth] = node->name;
153 	for (pnode = node->parent; pnode && depth < MAKEFS_MAX_TREE_DEPTH;
154 	     pnode = pnode->parent) {
155 		if (strcmp(pnode->name, ".") == 0)
156 			break;
157 		rp[++depth] = pnode->name;
158 	}
159 
160 	sb = sbuf_new(NULL, NULL, 0, SBUF_AUTOEXTEND);
161 	if (sb == NULL) {
162 		errno = ENOMEM;
163 		return (NULL);
164 	}
165 	while (depth > 0) {
166 		sbuf_cat(sb, rp[depth--]);
167 		sbuf_putc(sb, '/');
168 	}
169 	sbuf_cat(sb, rp[depth]);
170 	sbuf_finish(sb);
171 	res = strdup(sbuf_data(sb));
172 	sbuf_delete(sb);
173 	if (res == NULL)
174 		errno = ENOMEM;
175 	return res;
176 
177 }
178 
179 /* mtree_resolve() sets errno to indicate why NULL was returned. */
180 static char *
181 mtree_resolve(const char *spec, int *istemp)
182 {
183 	struct sbuf *sb;
184 	char *res, *var;
185 	const char *base, *p, *v;
186 	size_t len;
187 	int c, error, quoted, subst;
188 
189 	len = strlen(spec);
190 	if (len == 0) {
191 		errno = EINVAL;
192 		return (NULL);
193 	}
194 
195 	c = (len > 1) ? (spec[0] == spec[len - 1]) ? spec[0] : 0 : 0;
196 	*istemp = (c == '`') ? 1 : 0;
197 	subst = (c == '`' || c == '"') ? 1 : 0;
198 	quoted = (subst || c == '\'') ? 1 : 0;
199 
200 	if (!subst) {
201 		res = strdup(spec + quoted);
202 		if (res != NULL && quoted)
203 			res[len - 2] = '\0';
204 		return (res);
205 	}
206 
207 	sb = sbuf_new_auto();
208 	if (sb == NULL) {
209 		errno = ENOMEM;
210 		return (NULL);
211 	}
212 
213 	base = spec + 1;
214 	len -= 2;
215 	error = 0;
216 	while (len > 0) {
217 		p = strchr(base, '$');
218 		if (p == NULL) {
219 			sbuf_bcat(sb, base, len);
220 			base += len;
221 			len = 0;
222 			continue;
223 		}
224 		/* The following is safe. spec always starts with a quote. */
225 		if (p[-1] == '\\')
226 			p--;
227 		if (base != p) {
228 			sbuf_bcat(sb, base, p - base);
229 			len -= p - base;
230 			base = p;
231 		}
232 		if (*p == '\\') {
233 			sbuf_putc(sb, '$');
234 			base += 2;
235 			len -= 2;
236 			continue;
237 		}
238 		/* Skip the '$'. */
239 		base++;
240 		len--;
241 		/* Handle ${X} vs $X. */
242 		v = base;
243 		if (*base == '{') {
244 			p = strchr(v, '}');
245 			if (p == NULL)
246 				p = v;
247 		} else
248 			p = v;
249 		len -= (p + 1) - base;
250 		base = p + 1;
251 
252 		if (v == p) {
253 			sbuf_putc(sb, *v);
254 			continue;
255 		}
256 
257 		error = ENOMEM;
258 		var = calloc(p - v, 1);
259 		if (var == NULL)
260 			break;
261 
262 		memcpy(var, v + 1, p - v - 1);
263 		if (strcmp(var, ".CURDIR") == 0) {
264 			res = getcwd(NULL, 0);
265 			if (res == NULL)
266 				break;
267 		} else if (strcmp(var, ".PROG") == 0) {
268 			res = strdup(getprogname());
269 			if (res == NULL)
270 				break;
271 		} else {
272 			v = getenv(var);
273 			if (v != NULL) {
274 				res = strdup(v);
275 				if (res == NULL)
276 					break;
277 			} else
278 				res = NULL;
279 		}
280 		error = 0;
281 
282 		if (res != NULL) {
283 			sbuf_cat(sb, res);
284 			free(res);
285 		}
286 		free(var);
287 	}
288 
289 	sbuf_finish(sb);
290 	res = (error == 0) ? strdup(sbuf_data(sb)) : NULL;
291 	sbuf_delete(sb);
292 	if (res == NULL)
293 		errno = ENOMEM;
294 	return (res);
295 }
296 
297 static int
298 skip_over(FILE *fp, const char *cs)
299 {
300 	int c;
301 
302 	c = getc(fp);
303 	while (c != EOF && strchr(cs, c) != NULL)
304 		c = getc(fp);
305 	if (c != EOF) {
306 		ungetc(c, fp);
307 		return (0);
308 	}
309 	return (ferror(fp) ? errno : -1);
310 }
311 
312 static int
313 skip_to(FILE *fp, const char *cs)
314 {
315 	int c;
316 
317 	c = getc(fp);
318 	while (c != EOF && strchr(cs, c) == NULL)
319 		c = getc(fp);
320 	if (c != EOF) {
321 		ungetc(c, fp);
322 		return (0);
323 	}
324 	return (ferror(fp) ? errno : -1);
325 }
326 
327 static int
328 read_word(FILE *fp, char *buf, size_t bufsz)
329 {
330 	struct mtree_fileinfo *fi;
331 	size_t idx, qidx;
332 	int c, done, error, esc, qlvl;
333 
334 	if (bufsz == 0)
335 		return (EINVAL);
336 
337 	done = 0;
338 	esc = 0;
339 	idx = 0;
340 	qidx = -1;
341 	qlvl = 0;
342 	do {
343 		c = getc(fp);
344 		switch (c) {
345 		case EOF:
346 			buf[idx] = '\0';
347 			error = ferror(fp) ? errno : -1;
348 			if (error == -1)
349 				mtree_error("unexpected end of file");
350 			return (error);
351 		case '\\':
352 			esc++;
353 			if (esc == 1)
354 				continue;
355 			break;
356 		case '`':
357 		case '\'':
358 		case '"':
359 			if (esc)
360 				break;
361 			if (qlvl == 0) {
362 				qlvl++;
363 				qidx = idx;
364 			} else if (c == buf[qidx]) {
365 				qlvl--;
366 				if (qlvl > 0) {
367 					do {
368 						qidx--;
369 					} while (buf[qidx] != '`' &&
370 					    buf[qidx] != '\'' &&
371 					    buf[qidx] != '"');
372 				} else
373 					qidx = -1;
374 			} else {
375 				qlvl++;
376 				qidx = idx;
377 			}
378 			break;
379 		case ' ':
380 		case '\t':
381 		case '\n':
382 			if (!esc && qlvl == 0) {
383 				ungetc(c, fp);
384 				c = '\0';
385 				done = 1;
386 				break;
387 			}
388 			if (c == '\n') {
389 				/*
390 				 * We going to eat the newline ourselves.
391 				 */
392 				if (qlvl > 0)
393 					mtree_warning("quoted word straddles "
394 					    "onto next line.");
395 				fi = SLIST_FIRST(&mtree_fileinfo);
396 				fi->line++;
397 			}
398 			break;
399 		case 'a':
400 			if (esc)
401 				c = '\a';
402 			break;
403 		case 'b':
404 			if (esc)
405 				c = '\b';
406 			break;
407 		case 'f':
408 			if (esc)
409 				c = '\f';
410 			break;
411 		case 'n':
412 			if (esc)
413 				c = '\n';
414 			break;
415 		case 'r':
416 			if (esc)
417 				c = '\r';
418 			break;
419 		case 't':
420 			if (esc)
421 				c = '\t';
422 			break;
423 		case 'v':
424 			if (esc)
425 				c = '\v';
426 			break;
427 		}
428 		buf[idx++] = c;
429 		esc = 0;
430 	} while (idx < bufsz && !done);
431 
432 	if (idx >= bufsz) {
433 		mtree_error("word too long to fit buffer (max %zu characters)",
434 		    bufsz);
435 		skip_to(fp, " \t\n");
436 	}
437 	return (0);
438 }
439 
440 static fsnode *
441 create_node(const char *name, u_int type, fsnode *parent, fsnode *global)
442 {
443 	fsnode *n;
444 
445 	n = calloc(1, sizeof(*n));
446 	if (n == NULL)
447 		return (NULL);
448 
449 	n->name = strdup(name);
450 	if (n->name == NULL) {
451 		free(n);
452 		return (NULL);
453 	}
454 
455 	n->type = (type == 0) ? global->type : type;
456 	n->parent = parent;
457 
458 	n->inode = calloc(1, sizeof(*n->inode));
459 	if (n->inode == NULL) {
460 		free(n->name);
461 		free(n);
462 		return (NULL);
463 	}
464 
465 	/* Assign global options/defaults. */
466 	bcopy(global->inode, n->inode, sizeof(*n->inode));
467 	n->inode->st.st_mode = (n->inode->st.st_mode & ~S_IFMT) | n->type;
468 
469 	if (n->type == S_IFLNK)
470 		n->symlink = global->symlink;
471 	else if (n->type == S_IFREG)
472 		n->contents = global->contents;
473 
474 	return (n);
475 }
476 
477 static void
478 destroy_node(fsnode *n)
479 {
480 
481 	assert(n != NULL);
482 	assert(n->name != NULL);
483 	assert(n->inode != NULL);
484 
485 	free(n->inode);
486 	free(n->name);
487 	free(n);
488 }
489 
490 static int
491 read_number(const char *tok, u_int base, intmax_t *res, intmax_t min,
492     intmax_t max)
493 {
494 	char *end;
495 	intmax_t val;
496 
497 	val = strtoimax(tok, &end, base);
498 	if (end == tok || end[0] != '\0')
499 		return (EINVAL);
500 	if (val < min || val > max)
501 		return (EDOM);
502 	*res = val;
503 	return (0);
504 }
505 
506 static int
507 read_mtree_keywords(FILE *fp, fsnode *node)
508 {
509 	char keyword[PATH_MAX];
510 	char *name, *p, *value;
511 	struct group *grent;
512 	struct passwd *pwent;
513 	struct stat *st, sb;
514 	intmax_t num;
515 	u_long flset, flclr;
516 	int error, istemp, type;
517 
518 	st = &node->inode->st;
519 	do {
520 		error = skip_over(fp, " \t");
521 		if (error)
522 			break;
523 
524 		error = read_word(fp, keyword, sizeof(keyword));
525 		if (error)
526 			break;
527 
528 		if (keyword[0] == '\0')
529 			break;
530 
531 		value = strchr(keyword, '=');
532 		if (value != NULL)
533 			*value++ = '\0';
534 
535 		/*
536 		 * We use EINVAL, ENOATTR, ENOSYS and ENXIO to signal
537 		 * certain conditions:
538 		 *   EINVAL -	Value provided for a keyword that does
539 		 *		not take a value. The value is ignored.
540 		 *   ENOATTR -	Value missing for a keyword that needs
541 		 *		a value. The keyword is ignored.
542 		 *   ENOSYS -	Unsupported keyword encountered. The
543 		 *		keyword is ignored.
544 		 *   ENXIO -	Value provided for a keyword that does
545 		 *		not take a value. The value is ignored.
546 		 */
547 		switch (keyword[0]) {
548 		case 'c':
549 			if (strcmp(keyword, "contents") == 0) {
550 				if (value == NULL) {
551 					error = ENOATTR;
552 					break;
553 				}
554 				node->contents = strdup(value);
555 			} else
556 				error = ENOSYS;
557 			break;
558 		case 'f':
559 			if (strcmp(keyword, "flags") == 0) {
560 				if (value == NULL) {
561 					error = ENOATTR;
562 					break;
563 				}
564 				flset = flclr = 0;
565 				if (!strtofflags(&value, &flset, &flclr)) {
566 					st->st_flags &= ~flclr;
567 					st->st_flags |= flset;
568 				} else
569 					error = errno;
570 			} else
571 				error = ENOSYS;
572 			break;
573 		case 'g':
574 			if (strcmp(keyword, "gid") == 0) {
575 				if (value == NULL) {
576 					error = ENOATTR;
577 					break;
578 				}
579 				error = read_number(value, 10, &num,
580 				    0, UINT_MAX);
581 				if (!error)
582 					st->st_gid = num;
583 			} else if (strcmp(keyword, "gname") == 0) {
584 				if (value == NULL) {
585 					error = ENOATTR;
586 					break;
587 				}
588 				grent = getgrnam(value);
589 				if (grent != NULL)
590 					st->st_gid = grent->gr_gid;
591 				else
592 					error = errno;
593 			} else
594 				error = ENOSYS;
595 			break;
596 		case 'l':
597 			if (strcmp(keyword, "link") == 0) {
598 				if (value == NULL) {
599 					error = ENOATTR;
600 					break;
601 				}
602 				node->symlink = strdup(value);
603 			} else
604 				error = ENOSYS;
605 			break;
606 		case 'm':
607 			if (strcmp(keyword, "mode") == 0) {
608 				if (value == NULL) {
609 					error = ENOATTR;
610 					break;
611 				}
612 				if (value[0] >= '0' && value[0] <= '9') {
613 					error = read_number(value, 8, &num,
614 					    0, 07777);
615 					if (!error) {
616 						st->st_mode &= S_IFMT;
617 						st->st_mode |= num;
618 					}
619 				} else {
620 					/* Symbolic mode not supported. */
621 					error = EINVAL;
622 					break;
623 				}
624 			} else
625 				error = ENOSYS;
626 			break;
627 		case 'o':
628 			if (strcmp(keyword, "optional") == 0) {
629 				if (value != NULL)
630 					error = ENXIO;
631 				node->flags |= FSNODE_F_OPTIONAL;
632 			} else
633 				error = ENOSYS;
634 			break;
635 		case 's':
636 			if (strcmp(keyword, "size") == 0) {
637 				if (value == NULL) {
638 					error = ENOATTR;
639 					break;
640 				}
641 				error = read_number(value, 10, &num,
642 				    0, INTMAX_MAX);
643 				if (!error)
644 					st->st_size = num;
645 			} else
646 				error = ENOSYS;
647 			break;
648 		case 't':
649 			if (strcmp(keyword, "time") == 0) {
650 				if (value == NULL) {
651 					error = ENOATTR;
652 					break;
653 				}
654 				p = strchr(value, '.');
655 				if (p != NULL)
656 					*p++ = '\0';
657 				error = read_number(value, 10, &num, 0,
658 				    INTMAX_MAX);
659 				if (error)
660 					break;
661 				st->st_atime = num;
662 				st->st_ctime = num;
663 				st->st_mtime = num;
664 				error = read_number(p, 10, &num, 0,
665 				    INTMAX_MAX);
666 				if (error)
667 					break;
668 				if (num != 0)
669 					error = EINVAL;
670 			} else if (strcmp(keyword, "type") == 0) {
671 				if (value == NULL) {
672 					error = ENOATTR;
673 					break;
674 				}
675 				if (strcmp(value, "dir") == 0)
676 					node->type = S_IFDIR;
677 				else if (strcmp(value, "file") == 0)
678 					node->type = S_IFREG;
679 				else if (strcmp(value, "link") == 0)
680 					node->type = S_IFLNK;
681 				else
682 					error = EINVAL;
683 			} else
684 				error = ENOSYS;
685 			break;
686 		case 'u':
687 			if (strcmp(keyword, "uid") == 0) {
688 				if (value == NULL) {
689 					error = ENOATTR;
690 					break;
691 				}
692 				error = read_number(value, 10, &num,
693 				    0, UINT_MAX);
694 				if (!error)
695 					st->st_uid = num;
696 			} else if (strcmp(keyword, "uname") == 0) {
697 				if (value == NULL) {
698 					error = ENOATTR;
699 					break;
700 				}
701 				pwent = getpwnam(value);
702 				if (pwent != NULL)
703 					st->st_uid = pwent->pw_uid;
704 				else
705 					error = errno;
706 			} else
707 				error = ENOSYS;
708 			break;
709 		default:
710 			error = ENOSYS;
711 			break;
712 		}
713 
714 		switch (error) {
715 		case EINVAL:
716 			mtree_error("%s: invalid value '%s'", keyword, value);
717 			break;
718 		case ENOATTR:
719 			mtree_error("%s: keyword needs a value", keyword);
720 			break;
721 		case ENOSYS:
722 			mtree_warning("%s: unsupported keyword", keyword);
723 			break;
724 		case ENXIO:
725 			mtree_error("%s: keyword does not take a value",
726 			    keyword);
727 			break;
728 		}
729 	} while (1);
730 
731 	if (error)
732 		return (error);
733 
734 	st->st_mode = (st->st_mode & ~S_IFMT) | node->type;
735 
736 	/* Nothing more to do for the global defaults. */
737 	if (node->name == NULL)
738 		return (0);
739 
740 	/*
741 	 * Be intelligent about the file type.
742 	 */
743 	if (node->contents != NULL) {
744 		if (node->symlink != NULL) {
745 			mtree_error("%s: both link and contents keywords "
746 			    "defined", node->name);
747 			return (0);
748 		}
749 		type = S_IFREG;
750 	} else if (node->type != 0) {
751 		type = node->type;
752 		if (type == S_IFREG) {
753 			/* the named path is the default contents */
754 			node->contents = mtree_file_path(node);
755 		}
756 	} else
757 		type = (node->symlink != NULL) ? S_IFLNK : S_IFDIR;
758 
759 	if (node->type == 0)
760 		node->type = type;
761 
762 	if (node->type != type) {
763 		mtree_error("%s: file type and defined keywords to not match",
764 		    node->name);
765 		return (0);
766 	}
767 
768 	st->st_mode = (st->st_mode & ~S_IFMT) | node->type;
769 
770 	if (node->contents == NULL)
771 		return (0);
772 
773 	name = mtree_resolve(node->contents, &istemp);
774 	if (name == NULL)
775 		return (errno);
776 
777 	if (stat(name, &sb) != 0) {
778 		mtree_error("%s: contents file '%s' not found", node->name,
779 		    name);
780 		free(name);
781 		return (0);
782 	}
783 
784 	free(node->contents);
785 	node->contents = name;
786 	st->st_size = sb.st_size;
787 	return (0);
788 }
789 
790 static int
791 read_mtree_command(FILE *fp)
792 {
793 	char cmd[10];
794 	int error;
795 
796 	error = read_word(fp, cmd, sizeof(cmd));
797 	if (error)
798 		goto out;
799 
800 	error = read_mtree_keywords(fp, &mtree_global);
801 
802  out:
803 	skip_to(fp, "\n");
804 	(void)getc(fp);
805 	return (error);
806 }
807 
808 static int
809 read_mtree_spec1(FILE *fp, bool def, const char *name)
810 {
811 	fsnode *last, *node, *parent;
812 	u_int type;
813 	int error;
814 
815 	assert(name[0] != '\0');
816 
817 	/*
818 	 * Treat '..' specially, because it only changes our current
819 	 * directory. We don't create a node for it. We simply ignore
820 	 * any keywords that may appear on the line as well.
821 	 * Going up a directory is a little non-obvious. A directory
822 	 * node has a corresponding '.' child. The parent of '.' is
823 	 * not the '.' node of the parent directory, but the directory
824 	 * node within the parent to which the child relates. However,
825 	 * going up a directory means we need to find the '.' node to
826 	 * which the directoy node is linked.  This we can do via the
827 	 * first * pointer, because '.' is always the first entry in a
828 	 * directory.
829 	 */
830 	if (IS_DOTDOT(name)) {
831 		/* This deals with NULL pointers as well. */
832 		if (mtree_current == mtree_root) {
833 			mtree_warning("ignoring .. in root directory");
834 			return (0);
835 		}
836 
837 		node = mtree_current;
838 
839 		assert(node != NULL);
840 		assert(IS_DOT(node->name));
841 		assert(node->first == node);
842 
843 		/* Get the corresponding directory node in the parent. */
844 		node = mtree_current->parent;
845 
846 		assert(node != NULL);
847 		assert(!IS_DOT(node->name));
848 
849 		node = node->first;
850 
851 		assert(node != NULL);
852 		assert(IS_DOT(node->name));
853 		assert(node->first == node);
854 
855 		mtree_current = node;
856 		return (0);
857 	}
858 
859 	/*
860 	 * If we don't have a current directory and the first specification
861 	 * (either implicit or defined) is not '.', then we need to create
862 	 * a '.' node first (using a recursive call).
863 	 */
864 	if (!IS_DOT(name) && mtree_current == NULL) {
865 		error = read_mtree_spec1(fp, false, ".");
866 		if (error)
867 			return (error);
868 	}
869 
870 	/*
871 	 * Lookup the name in the current directory (if we have a current
872 	 * directory) to make sure we do not create multiple nodes for the
873 	 * same component. For non-definitions, if we find a node with the
874 	 * same name, simply change the current directory. For definitions
875 	 * more happens.
876 	 */
877 	last = NULL;
878 	node = mtree_current;
879 	while (node != NULL) {
880 		assert(node->first == mtree_current);
881 
882 		if (strcmp(name, node->name) == 0) {
883 			if (def == true) {
884 				mtree_error("duplicate definition of %s",
885 				    name);
886 				return (0);
887 			}
888 
889 			if (node->type != S_IFDIR) {
890 				mtree_error("%s is not a directory", name);
891 				return (0);
892 			}
893 
894 			assert(!IS_DOT(name));
895 
896 			node = node->child;
897 
898 			assert(node != NULL);
899 			assert(IS_DOT(node->name));
900 
901 			mtree_current = node;
902 			return (0);
903 		}
904 
905 		last = node;
906 		node = last->next;
907 	}
908 
909 	parent = (mtree_current != NULL) ? mtree_current->parent : NULL;
910 	type = (def == false || IS_DOT(name)) ? S_IFDIR : 0;
911 	node = create_node(name, type, parent, &mtree_global);
912 	if (node == NULL)
913 		return (ENOMEM);
914 
915 	if (def == true) {
916 		error = read_mtree_keywords(fp, node);
917 		if (error) {
918 			destroy_node(node);
919 			return (error);
920 		}
921 	}
922 
923 	node->first = (mtree_current != NULL) ? mtree_current : node;
924 
925 	if (last != NULL)
926 		last->next = node;
927 
928 	if (node->type != S_IFDIR)
929 		return (0);
930 
931 	if (!IS_DOT(node->name)) {
932 		parent = node;
933 		node = create_node(".", S_IFDIR, parent, parent);
934 		if (node == NULL) {
935 			last->next = NULL;
936 			destroy_node(parent);
937 			return (ENOMEM);
938 		}
939 		parent->child = node;
940 		node->first = node;
941 	}
942 
943 	assert(node != NULL);
944 	assert(IS_DOT(node->name));
945 	assert(node->first == node);
946 
947 	mtree_current = node;
948 	if (mtree_root == NULL)
949 		mtree_root = node;
950 
951 	return (0);
952 }
953 
954 static int
955 read_mtree_spec(FILE *fp)
956 {
957 	char pathspec[PATH_MAX];
958 	char *cp;
959 	int error;
960 
961 	error = read_word(fp, pathspec, sizeof(pathspec));
962 	if (error)
963 		goto out;
964 
965 	cp = strchr(pathspec, '/');
966 	if (cp != NULL) {
967 		/* Absolute pathname */
968 		mtree_current = mtree_root;
969 
970 		do {
971 			*cp++ = '\0';
972 
973 			/* Disallow '.' and '..' as components. */
974 			if (IS_DOT(pathspec) || IS_DOTDOT(pathspec)) {
975 				mtree_error("absolute path cannot contain . "
976 				    "or .. components");
977 				goto out;
978 			}
979 
980 			/* Ignore multiple adjacent slashes. */
981 			if (pathspec[0] != '\0')
982 				error = read_mtree_spec1(fp, false, pathspec);
983 			memmove(pathspec, cp, strlen(cp) + 1);
984 			cp = strchr(pathspec, '/');
985 		} while (!error && cp != NULL);
986 
987 		/* Disallow '.' and '..' as the last component. */
988 		if (!error && (IS_DOT(pathspec) || IS_DOTDOT(pathspec))) {
989 			mtree_error("absolute path cannot contain . or .. "
990 			    "components");
991 			goto out;
992 		}
993 	}
994 
995 	/* Ignore absolute specfications that end with a slash. */
996 	if (!error && pathspec[0] != '\0')
997 		error = read_mtree_spec1(fp, true, pathspec);
998 
999  out:
1000 	skip_to(fp, "\n");
1001 	(void)getc(fp);
1002 	return (error);
1003 }
1004 
1005 fsnode *
1006 read_mtree(const char *fname, fsnode *node)
1007 {
1008 	struct mtree_fileinfo *fi;
1009 	FILE *fp;
1010 	int c, error;
1011 
1012 	/* We do not yet support nesting... */
1013 	assert(node == NULL);
1014 
1015 	if (strcmp(fname, "-") == 0)
1016 		fp = stdin;
1017 	else {
1018 		fp = fopen(fname, "r");
1019 		if (fp == NULL)
1020 			err(1, "Can't open `%s'", fname);
1021 	}
1022 
1023 	error = mtree_file_push(fname, fp);
1024 	if (error)
1025 		goto out;
1026 
1027 	bzero(&mtree_global, sizeof(mtree_global));
1028 	bzero(&mtree_global_inode, sizeof(mtree_global_inode));
1029 	mtree_global.inode = &mtree_global_inode;
1030 	mtree_global_inode.nlink = 1;
1031 	mtree_global_inode.st.st_atime = mtree_global_inode.st.st_ctime =
1032 	    mtree_global_inode.st.st_mtime = time(NULL);
1033 	errors = warnings = 0;
1034 
1035 	setgroupent(1);
1036 	setpassent(1);
1037 
1038 	mtree_root = node;
1039 	mtree_current = node;
1040 	do {
1041 		/* Start of a new line... */
1042 		fi = SLIST_FIRST(&mtree_fileinfo);
1043 		fi->line++;
1044 
1045 		error = skip_over(fp, " \t");
1046 		if (error)
1047 			break;
1048 
1049 		c = getc(fp);
1050 		if (c == EOF) {
1051 			error = ferror(fp) ? errno : -1;
1052 			break;
1053 		}
1054 
1055 		switch (c) {
1056 		case '\n':		/* empty line */
1057 			error = 0;
1058 			break;
1059 		case '#':		/* comment -- skip to end of line. */
1060 			error = skip_to(fp, "\n");
1061 			if (!error)
1062 				(void)getc(fp);
1063 			break;
1064 		case '/':		/* special commands */
1065 			error = read_mtree_command(fp);
1066 			break;
1067 		default:		/* specification */
1068 			ungetc(c, fp);
1069 			error = read_mtree_spec(fp);
1070 			break;
1071 		}
1072 	} while (!error);
1073 
1074 	endpwent();
1075 	endgrent();
1076 
1077 	if (error <= 0 && (errors || warnings)) {
1078 		warnx("%u error(s) and %u warning(s) in mtree manifest",
1079 		    errors, warnings);
1080 		if (errors)
1081 			exit(1);
1082 	}
1083 
1084  out:
1085 	if (error > 0)
1086 		errc(1, error, "Error reading mtree file");
1087 
1088 	if (fp != stdin)
1089 		fclose(fp);
1090 
1091 	if (mtree_root != NULL)
1092 		return (mtree_root);
1093 
1094 	/* Handle empty specifications. */
1095 	node = create_node(".", S_IFDIR, NULL, &mtree_global);
1096 	node->first = node;
1097 	return (node);
1098 }
1099