xref: /freebsd-src/usr.sbin/kldxref/kldxref.c (revision 4a3cf5f329d69076aa9d093d596eb0ee82d917f5)
1 /*-
2  * SPDX-License-Identifier: BSD-4-Clause
3  *
4  * Copyright (c) 2000, Boris Popov
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  *    This product includes software developed by Boris Popov.
18  * 4. Neither the name of the author nor the names of any co-contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #include <sys/types.h>
36 #include <sys/param.h>
37 #include <sys/endian.h>
38 #include <sys/exec.h>
39 #include <sys/queue.h>
40 #include <sys/kernel.h>
41 #include <sys/reboot.h>
42 #include <sys/linker.h>
43 #include <sys/stat.h>
44 #include <sys/module.h>
45 
46 #include <ctype.h>
47 #include <err.h>
48 #include <errno.h>
49 #include <fts.h>
50 #include <stdbool.h>
51 #include <stdio.h>
52 #include <stdlib.h>
53 #include <string.h>
54 #include <unistd.h>
55 #include <machine/elf.h>
56 
57 #include "ef.h"
58 
59 #define	MAXRECSIZE	(64 << 10)	/* 64k */
60 #define check(val)	if ((error = (val)) != 0) break
61 
62 static bool dflag;	/* do not create a hint file, only write on stdout */
63 static int verbose;
64 
65 static FILE *fxref;	/* current hints file */
66 
67 static const char *xref_file = "linker.hints";
68 
69 /*
70  * A record is stored in the static buffer recbuf before going to disk.
71  */
72 static char recbuf[MAXRECSIZE];
73 static int recpos;	/* current write position */
74 static int reccnt;	/* total record written to this file so far */
75 
76 static void
77 intalign(void)
78 {
79 
80 	recpos = roundup2(recpos, sizeof(int));
81 }
82 
83 static void
84 record_start(void)
85 {
86 
87 	recpos = 0;
88 	memset(recbuf, 0, MAXRECSIZE);
89 }
90 
91 static int
92 record_end(void)
93 {
94 
95 	if (recpos == 0)
96 		return (0);
97 	reccnt++;
98 	intalign();
99 	fwrite(&recpos, sizeof(recpos), 1, fxref);
100 	return (fwrite(recbuf, recpos, 1, fxref) != 1 ? errno : 0);
101 }
102 
103 static int
104 record_buf(const void *buf, size_t size)
105 {
106 
107 	if (MAXRECSIZE - recpos < size)
108 		errx(1, "record buffer overflow");
109 	memcpy(recbuf + recpos, buf, size);
110 	recpos += size;
111 	return (0);
112 }
113 
114 /*
115  * An int is stored in host order and aligned
116  */
117 static int
118 record_int(int val)
119 {
120 
121 	intalign();
122 	return (record_buf(&val, sizeof(val)));
123 }
124 
125 /*
126  * A string is stored as 1-byte length plus data, no padding
127  */
128 static int
129 record_string(const char *str)
130 {
131 	int error;
132 	size_t len;
133 	u_char val;
134 
135 	if (dflag)
136 		return (0);
137 	val = len = strlen(str);
138 	if (len > 255)
139 		errx(1, "string %s too long", str);
140 	error = record_buf(&val, sizeof(val));
141 	if (error != 0)
142 		return (error);
143 	return (record_buf(str, len));
144 }
145 
146 /* From sys/isa/pnp.c */
147 static char *
148 pnp_eisaformat(uint32_t id)
149 {
150 	uint8_t *data;
151 	static char idbuf[8];
152 	const char  hextoascii[] = "0123456789abcdef";
153 
154 	id = htole32(id);
155 	data = (uint8_t *)&id;
156 	idbuf[0] = '@' + ((data[0] & 0x7c) >> 2);
157 	idbuf[1] = '@' + (((data[0] & 0x3) << 3) + ((data[1] & 0xe0) >> 5));
158 	idbuf[2] = '@' + (data[1] & 0x1f);
159 	idbuf[3] = hextoascii[(data[2] >> 4)];
160 	idbuf[4] = hextoascii[(data[2] & 0xf)];
161 	idbuf[5] = hextoascii[(data[3] >> 4)];
162 	idbuf[6] = hextoascii[(data[3] & 0xf)];
163 	idbuf[7] = 0;
164 	return (idbuf);
165 }
166 
167 struct pnp_elt
168 {
169 	int	pe_kind;	/* What kind of entry */
170 #define TYPE_SZ_MASK	0x0f
171 #define TYPE_FLAGGED	0x10	/* all f's is a wildcard */
172 #define	TYPE_INT	0x20	/* Is a number */
173 #define TYPE_PAIRED	0x40
174 #define TYPE_LE		0x80	/* Matches <= this value */
175 #define TYPE_GE		0x100	/* Matches >= this value */
176 #define TYPE_MASK	0x200	/* Specifies a mask to follow */
177 #define TYPE_U8		(1 | TYPE_INT)
178 #define TYPE_V8		(1 | TYPE_INT | TYPE_FLAGGED)
179 #define TYPE_G16	(2 | TYPE_INT | TYPE_GE)
180 #define TYPE_L16	(2 | TYPE_INT | TYPE_LE)
181 #define TYPE_M16	(2 | TYPE_INT | TYPE_MASK)
182 #define TYPE_U16	(2 | TYPE_INT)
183 #define TYPE_V16	(2 | TYPE_INT | TYPE_FLAGGED)
184 #define TYPE_U32	(4 | TYPE_INT)
185 #define TYPE_V32	(4 | TYPE_INT | TYPE_FLAGGED)
186 #define TYPE_W32	(4 | TYPE_INT | TYPE_PAIRED)
187 #define TYPE_D		7
188 #define TYPE_Z		8
189 #define TYPE_P		9
190 #define TYPE_E		10
191 #define TYPE_T		11
192 	int	pe_offset;	/* Offset within the element */
193 	char *	pe_key;		/* pnp key name */
194 	TAILQ_ENTRY(pnp_elt) next; /* Link */
195 };
196 typedef TAILQ_HEAD(pnp_head, pnp_elt) pnp_list;
197 
198 /*
199  * this function finds the data from the pnp table, as described by the
200  * the description and creates a new output (new_desc). This output table
201  * is a form that's easier for the agent that's automatically loading the
202  * modules.
203  *
204  * The format output is the simplified string from this routine in the
205  * same basic format as the pnp string, as documented in sys/module.h.
206  * First a string describing the format is output, the a count of the
207  * number of records, then each record. The format string also describes
208  * the length of each entry (though it isn't a fixed length when strings
209  * are present).
210  *
211  *	type	Output		Meaning
212  *	I	uint32_t	Integer equality comparison
213  *	J	uint32_t	Pair of uint16_t fields converted to native
214  *				byte order. The two fields both must match.
215  *	G	uint32_t	Greater than or equal to
216  *	L	uint32_t	Less than or equal to
217  *	M	uint32_t	Mask of which fields to test. Fields that
218  *				take up space increment the count. This
219  *				field must be first, and resets the count.
220  *	D	string		Description of the device this pnp info is for
221  *	Z	string		pnp string must match this
222  *	T	nothing		T fields set pnp values that must be true for
223  *				the entire table.
224  * Values are packed the same way that other values are packed in this file.
225  * Strings and int32_t's start on a 32-bit boundary and are padded with 0
226  * bytes. Objects that are smaller than uint32_t are converted, without
227  * sign extension to uint32_t to simplify parsing downstream.
228  */
229 static int
230 parse_pnp_list(const char *desc, char **new_desc, pnp_list *list)
231 {
232 	const char *walker, *ep;
233 	const char *colon, *semi;
234 	struct pnp_elt *elt;
235 	char type[8], key[32];
236 	int off;
237 	size_t new_desc_size;
238 	FILE *fp;
239 
240 	walker = desc;
241 	ep = desc + strlen(desc);
242 	off = 0;
243 	fp = open_memstream(new_desc, &new_desc_size);
244 	if (fp == NULL)
245 		err(1, "Could not open new memory stream");
246 	if (verbose > 1)
247 		printf("Converting %s into a list\n", desc);
248 	while (walker < ep) {
249 		colon = strchr(walker, ':');
250 		semi = strchr(walker, ';');
251 		if (semi != NULL && semi < colon)
252 			goto err;
253 		if (colon - walker > sizeof(type))
254 			goto err;
255 		strncpy(type, walker, colon - walker);
256 		type[colon - walker] = '\0';
257 		if (semi != NULL) {
258 			if (semi - colon >= sizeof(key))
259 				goto err;
260 			strncpy(key, colon + 1, semi - colon - 1);
261 			key[semi - colon - 1] = '\0';
262 			walker = semi + 1;
263 			/* Fail safe if we have spaces after ; */
264 			while (walker < ep && isspace(*walker))
265 				walker++;
266 		} else {
267 			if (strlen(colon + 1) >= sizeof(key))
268 				goto err;
269 			strcpy(key, colon + 1);
270 			walker = ep;
271 		}
272 		if (verbose > 1)
273 			printf("Found type %s for name %s\n", type, key);
274 		/* Skip pointer place holders */
275 		if (strcmp(type, "P") == 0) {
276 			off += sizeof(void *);
277 			continue;
278 		}
279 
280 		/*
281 		 * Add a node of the appropriate type
282 		 */
283 		elt = malloc(sizeof(struct pnp_elt) + strlen(key) + 1);
284 		TAILQ_INSERT_TAIL(list, elt, next);
285 		elt->pe_key = (char *)(elt + 1);
286 		elt->pe_offset = off;
287 		if (strcmp(type, "U8") == 0)
288 			elt->pe_kind = TYPE_U8;
289 		else if (strcmp(type, "V8") == 0)
290 			elt->pe_kind = TYPE_V8;
291 		else if (strcmp(type, "G16") == 0)
292 			elt->pe_kind = TYPE_G16;
293 		else if (strcmp(type, "L16") == 0)
294 			elt->pe_kind = TYPE_L16;
295 		else if (strcmp(type, "M16") == 0)
296 			elt->pe_kind = TYPE_M16;
297 		else if (strcmp(type, "U16") == 0)
298 			elt->pe_kind = TYPE_U16;
299 		else if (strcmp(type, "V16") == 0)
300 			elt->pe_kind = TYPE_V16;
301 		else if (strcmp(type, "U32") == 0)
302 			elt->pe_kind = TYPE_U32;
303 		else if (strcmp(type, "V32") == 0)
304 			elt->pe_kind = TYPE_V32;
305 		else if (strcmp(type, "W32") == 0)
306 			elt->pe_kind = TYPE_W32;
307 		else if (strcmp(type, "D") == 0)	/* description char * */
308 			elt->pe_kind = TYPE_D;
309 		else if (strcmp(type, "Z") == 0)	/* char * to match */
310 			elt->pe_kind = TYPE_Z;
311 		else if (strcmp(type, "P") == 0)	/* Pointer -- ignored */
312 			elt->pe_kind = TYPE_P;
313 		else if (strcmp(type, "E") == 0)	/* EISA PNP ID, as uint32_t */
314 			elt->pe_kind = TYPE_E;
315 		else if (strcmp(type, "T") == 0)
316 			elt->pe_kind = TYPE_T;
317 		else
318 			goto err;
319 		/*
320 		 * Maybe the rounding here needs to be more nuanced and/or somehow
321 		 * architecture specific. Fortunately, most tables in the system
322 		 * have sane ordering of types.
323 		 */
324 		if (elt->pe_kind & TYPE_INT) {
325 			elt->pe_offset = roundup2(elt->pe_offset, elt->pe_kind & TYPE_SZ_MASK);
326 			off = elt->pe_offset + (elt->pe_kind & TYPE_SZ_MASK);
327 		} else if (elt->pe_kind == TYPE_E) {
328 			/* Type E stored as Int, displays as string */
329 			elt->pe_offset = roundup2(elt->pe_offset, sizeof(uint32_t));
330 			off = elt->pe_offset + sizeof(uint32_t);
331 		} else if (elt->pe_kind == TYPE_T) {
332 			/* doesn't actually consume space in the table */
333 			off = elt->pe_offset;
334 		} else {
335 			elt->pe_offset = roundup2(elt->pe_offset, sizeof(void *));
336 			off = elt->pe_offset + sizeof(void *);
337 		}
338 		if (elt->pe_kind & TYPE_PAIRED) {
339 			char *word, *ctx, newtype;
340 
341 			for (word = strtok_r(key, "/", &ctx);
342 			     word; word = strtok_r(NULL, "/", &ctx)) {
343 				newtype = elt->pe_kind & TYPE_FLAGGED ? 'J' : 'I';
344 				fprintf(fp, "%c:%s;", newtype, word);
345 			}
346 		}
347 		else {
348 			char newtype;
349 
350 			if (elt->pe_kind & TYPE_FLAGGED)
351 				newtype = 'J';
352 			else if (elt->pe_kind & TYPE_GE)
353 				newtype = 'G';
354 			else if (elt->pe_kind & TYPE_LE)
355 				newtype = 'L';
356 			else if (elt->pe_kind & TYPE_MASK)
357 				newtype = 'M';
358 			else if (elt->pe_kind & TYPE_INT)
359 				newtype = 'I';
360 			else if (elt->pe_kind == TYPE_D)
361 				newtype = 'D';
362 			else if (elt->pe_kind == TYPE_Z || elt->pe_kind == TYPE_E)
363 				newtype = 'Z';
364 			else if (elt->pe_kind == TYPE_T)
365 				newtype = 'T';
366 			else
367 				errx(1, "Impossible type %x\n", elt->pe_kind);
368 			fprintf(fp, "%c:%s;", newtype, key);
369 		}
370 	}
371 	if (ferror(fp) != 0) {
372 		fclose(fp);
373 		errx(1, "Exhausted space converting description %s", desc);
374 	}
375 	if (fclose(fp) != 0)
376 		errx(1, "Failed to close memory stream");
377 	return (0);
378 err:
379 	errx(1, "Parse error of description string %s", desc);
380 }
381 
382 static int
383 parse_entry(struct mod_metadata *md, const char *cval,
384     struct elf_file *ef, const char *kldname)
385 {
386 	struct mod_depend mdp;
387 	struct mod_version mdv;
388 	struct mod_pnp_match_info pnp;
389 	char descr[1024];
390 	Elf_Off data;
391 	int error, i;
392 	size_t len;
393 	char *walker;
394 	void *table;
395 
396 	data = (Elf_Off)md->md_data;
397 	error = 0;
398 	record_start();
399 	switch (md->md_type) {
400 	case MDT_DEPEND:
401 		if (!dflag)
402 			break;
403 		check(EF_SEG_READ(ef, data, sizeof(mdp), &mdp));
404 		printf("  depends on %s.%d (%d,%d)\n", cval,
405 		    mdp.md_ver_preferred, mdp.md_ver_minimum, mdp.md_ver_maximum);
406 		break;
407 	case MDT_VERSION:
408 		check(EF_SEG_READ(ef, data, sizeof(mdv), &mdv));
409 		if (dflag) {
410 			printf("  interface %s.%d\n", cval, mdv.mv_version);
411 		} else {
412 			record_int(MDT_VERSION);
413 			record_string(cval);
414 			record_int(mdv.mv_version);
415 			record_string(kldname);
416 		}
417 		break;
418 	case MDT_MODULE:
419 		if (dflag) {
420 			printf("  module %s\n", cval);
421 		} else {
422 			record_int(MDT_MODULE);
423 			record_string(cval);
424 			record_string(kldname);
425 		}
426 		break;
427 	case MDT_PNP_INFO:
428 		check(EF_SEG_READ_REL(ef, data, sizeof(pnp), &pnp));
429 		check(EF_SEG_READ_STRING(ef, (Elf_Off)pnp.descr, sizeof(descr), descr));
430 		descr[sizeof(descr) - 1] = '\0';
431 		if (dflag) {
432 			printf("  pnp info for bus %s format %s %d entries of %d bytes\n",
433 			    cval, descr, pnp.num_entry, pnp.entry_len);
434 		} else {
435 			pnp_list list;
436 			struct pnp_elt *elt, *elt_tmp;
437 			char *new_descr;
438 
439 			if (verbose > 1)
440 				printf("  pnp info for bus %s format %s %d entries of %d bytes\n",
441 				    cval, descr, pnp.num_entry, pnp.entry_len);
442 			/*
443 			 * Parse descr to weed out the chaff and to create a list
444 			 * of offsets to output.
445 			 */
446 			TAILQ_INIT(&list);
447 			parse_pnp_list(descr, &new_descr, &list);
448 			record_int(MDT_PNP_INFO);
449 			record_string(cval);
450 			record_string(new_descr);
451 			record_int(pnp.num_entry);
452 			len = pnp.num_entry * pnp.entry_len;
453 			walker = table = malloc(len);
454 			check(EF_SEG_READ_REL(ef, (Elf_Off)pnp.table, len, table));
455 
456 			/*
457 			 * Walk the list and output things. We've collapsed all the
458 			 * variant forms of the table down to just ints and strings.
459 			 */
460 			for (i = 0; i < pnp.num_entry; i++) {
461 				TAILQ_FOREACH(elt, &list, next) {
462 					uint8_t v1;
463 					uint16_t v2;
464 					uint32_t v4;
465 					int	value;
466 					char buffer[1024];
467 
468 					if (elt->pe_kind == TYPE_W32) {
469 						memcpy(&v4, walker + elt->pe_offset, sizeof(v4));
470 						value = v4 & 0xffff;
471 						record_int(value);
472 						if (verbose > 1)
473 							printf("W32:%#x", value);
474 						value = (v4 >> 16) & 0xffff;
475 						record_int(value);
476 						if (verbose > 1)
477 							printf(":%#x;", value);
478 					} else if (elt->pe_kind & TYPE_INT) {
479 						switch (elt->pe_kind & TYPE_SZ_MASK) {
480 						case 1:
481 							memcpy(&v1, walker + elt->pe_offset, sizeof(v1));
482 							if ((elt->pe_kind & TYPE_FLAGGED) && v1 == 0xff)
483 								value = -1;
484 							else
485 								value = v1;
486 							break;
487 						case 2:
488 							memcpy(&v2, walker + elt->pe_offset, sizeof(v2));
489 							if ((elt->pe_kind & TYPE_FLAGGED) && v2 == 0xffff)
490 								value = -1;
491 							else
492 								value = v2;
493 							break;
494 						case 4:
495 							memcpy(&v4, walker + elt->pe_offset, sizeof(v4));
496 							if ((elt->pe_kind & TYPE_FLAGGED) && v4 == 0xffffffff)
497 								value = -1;
498 							else
499 								value = v4;
500 							break;
501 						default:
502 							errx(1, "Invalid size somehow %#x", elt->pe_kind);
503 						}
504 						if (verbose > 1)
505 							printf("I:%#x;", value);
506 						record_int(value);
507 					} else if (elt->pe_kind == TYPE_T) {
508 						/* Do nothing */
509 					} else { /* E, Z or D -- P already filtered */
510 						if (elt->pe_kind == TYPE_E) {
511 							memcpy(&v4, walker + elt->pe_offset, sizeof(v4));
512 							strcpy(buffer, pnp_eisaformat(v4));
513 						} else {
514 							char *ptr;
515 
516 							ptr = *(char **)(walker + elt->pe_offset);
517 							buffer[0] = '\0';
518 							if (ptr != NULL) {
519 								EF_SEG_READ_STRING(ef, (Elf_Off)ptr,
520 								    sizeof(buffer), buffer);
521 								buffer[sizeof(buffer) - 1] = '\0';
522 							}
523 						}
524 						if (verbose > 1)
525 							printf("%c:%s;", elt->pe_kind == TYPE_E ? 'E' : (elt->pe_kind == TYPE_Z ? 'Z' : 'D'), buffer);
526 						record_string(buffer);
527 					}
528 				}
529 				if (verbose > 1)
530 					printf("\n");
531 				walker += pnp.entry_len;
532 			}
533 			/* Now free it */
534 			TAILQ_FOREACH_SAFE(elt, &list, next, elt_tmp) {
535 				TAILQ_REMOVE(&list, elt, next);
536 				free(elt);
537 			}
538 			free(table);
539 		}
540 		break;
541 	default:
542 		warnx("unknown metadata record %d in file %s", md->md_type, kldname);
543 	}
544 	if (!error)
545 		record_end();
546 	return (error);
547 }
548 
549 static int
550 read_kld(char *filename, char *kldname)
551 {
552 	struct mod_metadata md;
553 	struct elf_file ef;
554 	void **p;
555 	int error, eftype;
556 	long start, finish, entries, i;
557 	char cval[MAXMODNAME + 1];
558 
559 	if (verbose || dflag)
560 		printf("%s\n", filename);
561 	error = ef_open(filename, &ef, verbose);
562 	if (error != 0) {
563 		error = ef_obj_open(filename, &ef, verbose);
564 		if (error != 0) {
565 			if (verbose)
566 				warnc(error, "elf_open(%s)", filename);
567 			return (error);
568 		}
569 	}
570 	eftype = EF_GET_TYPE(&ef);
571 	if (eftype != EFT_KLD && eftype != EFT_KERNEL)  {
572 		EF_CLOSE(&ef);
573 		return (0);
574 	}
575 	do {
576 		check(EF_LOOKUP_SET(&ef, MDT_SETNAME, &start, &finish,
577 		    &entries));
578 		check(EF_SEG_READ_ENTRY_REL(&ef, start, sizeof(*p) * entries,
579 		    (void *)&p));
580 		/*
581 		 * Do a first pass to find MDT_MODULE.  It is required to be
582 		 * ordered first in the output linker.hints stream because it
583 		 * serves as an implicit record boundary between distinct klds
584 		 * in the stream.  Other MDTs only make sense in the context of
585 		 * a specific MDT_MODULE.
586 		 *
587 		 * Some compilers (e.g., GCC 6.4.0 xtoolchain) or binutils
588 		 * (e.g., GNU binutils 2.32 objcopy/ld.bfd) can reorder
589 		 * MODULE_METADATA set entries relative to the source ordering.
590 		 * This is permitted by the C standard; memory layout of
591 		 * file-scope objects is left implementation-defined.  There is
592 		 * no requirement that source code ordering is retained.
593 		 *
594 		 * Handle that here by taking two passes to ensure MDT_MODULE
595 		 * records are emitted to linker.hints before other MDT records
596 		 * in the same kld.
597 		 */
598 		for (i = 0; i < entries; i++) {
599 			check(EF_SEG_READ_REL(&ef, (Elf_Off)p[i], sizeof(md),
600 			    &md));
601 			check(EF_SEG_READ_STRING(&ef, (Elf_Off)md.md_cval,
602 			    sizeof(cval), cval));
603 			if (md.md_type == MDT_MODULE) {
604 				parse_entry(&md, cval, &ef, kldname);
605 				break;
606 			}
607 		}
608 		if (error != 0) {
609 			warnc(error, "error while reading %s", filename);
610 			break;
611 		}
612 
613 		/*
614 		 * Second pass for all !MDT_MODULE entries.
615 		 */
616 		for (i = 0; i < entries; i++) {
617 			check(EF_SEG_READ_REL(&ef, (Elf_Off)p[i], sizeof(md),
618 			    &md));
619 			check(EF_SEG_READ_STRING(&ef, (Elf_Off)md.md_cval,
620 			    sizeof(cval), cval));
621 			if (md.md_type != MDT_MODULE)
622 				parse_entry(&md, cval, &ef, kldname);
623 		}
624 		if (error != 0)
625 			warnc(error, "error while reading %s", filename);
626 		free(p);
627 	} while(0);
628 	EF_CLOSE(&ef);
629 	return (error);
630 }
631 
632 /*
633  * Create a temp file in directory root, make sure we don't
634  * overflow the buffer for the destination name
635  */
636 static FILE *
637 maketempfile(char *dest, const char *root)
638 {
639 	char *p;
640 	int n, fd;
641 
642 	p = strrchr(root, '/');
643 	n = p != NULL ? p - root + 1 : 0;
644 	if (snprintf(dest, MAXPATHLEN, "%.*slhint.XXXXXX", n, root) >=
645 	    MAXPATHLEN) {
646 		errno = ENAMETOOLONG;
647 		return (NULL);
648 	}
649 
650 	fd = mkstemp(dest);
651 	if (fd < 0)
652 		return (NULL);
653 	fchmod(fd, 0644);	/* nothing secret in the file */
654 	return (fdopen(fd, "w+"));
655 }
656 
657 static char xrefname[MAXPATHLEN], tempname[MAXPATHLEN];
658 
659 static void
660 usage(void)
661 {
662 
663 	fprintf(stderr, "%s\n",
664 	    "usage: kldxref [-Rdv] [-f hintsfile] path ..."
665 	);
666 	exit(1);
667 }
668 
669 static int
670 compare(const FTSENT *const *a, const FTSENT *const *b)
671 {
672 
673 	if ((*a)->fts_info == FTS_D && (*b)->fts_info != FTS_D)
674 		return (1);
675 	if ((*a)->fts_info != FTS_D && (*b)->fts_info == FTS_D)
676 		return (-1);
677 	return (strcmp((*a)->fts_name, (*b)->fts_name));
678 }
679 
680 int
681 main(int argc, char *argv[])
682 {
683 	FTS *ftsp;
684 	FTSENT *p;
685 	char *dot = NULL;
686 	int opt, fts_options, ival;
687 	struct stat sb;
688 
689 	fts_options = FTS_PHYSICAL;
690 
691 	while ((opt = getopt(argc, argv, "Rdf:v")) != -1) {
692 		switch (opt) {
693 		case 'd':	/* no hint file, only print on stdout */
694 			dflag = true;
695 			break;
696 		case 'f':	/* use this name instead of linker.hints */
697 			xref_file = optarg;
698 			break;
699 		case 'v':
700 			verbose++;
701 			break;
702 		case 'R':	/* recurse on directories */
703 			fts_options |= FTS_COMFOLLOW;
704 			break;
705 		default:
706 			usage();
707 			/* NOTREACHED */
708 		}
709 	}
710 	if (argc - optind < 1)
711 		usage();
712 	argc -= optind;
713 	argv += optind;
714 
715 	if (stat(argv[0], &sb) != 0)
716 		err(1, "%s", argv[0]);
717 	if ((sb.st_mode & S_IFDIR) == 0 && !dflag) {
718 		errno = ENOTDIR;
719 		err(1, "%s", argv[0]);
720 	}
721 
722 	ftsp = fts_open(argv, fts_options, compare);
723 	if (ftsp == NULL)
724 		exit(1);
725 
726 	for (;;) {
727 		p = fts_read(ftsp);
728 		if ((p == NULL || p->fts_info == FTS_D) && fxref) {
729 			/* close and rename the current hint file */
730 			fclose(fxref);
731 			fxref = NULL;
732 			if (reccnt != 0) {
733 				rename(tempname, xrefname);
734 			} else {
735 				/* didn't find any entry, ignore this file */
736 				unlink(tempname);
737 				unlink(xrefname);
738 			}
739 		}
740 		if (p == NULL)
741 			break;
742 		if (p->fts_info == FTS_D && !dflag) {
743 			/* visiting a new directory, create a new hint file */
744 			snprintf(xrefname, sizeof(xrefname), "%s/%s",
745 			    ftsp->fts_path, xref_file);
746 			fxref = maketempfile(tempname, ftsp->fts_path);
747 			if (fxref == NULL)
748 				err(1, "can't create %s", tempname);
749 			ival = 1;
750 			fwrite(&ival, sizeof(ival), 1, fxref);
751 			reccnt = 0;
752 		}
753 		/* skip non-files.. */
754 		if (p->fts_info != FTS_F)
755 			continue;
756 		/*
757 		 * Skip files that generate errors like .debug, .symbol and .pkgsave
758 		 * by generally skipping all files with 2 dots.
759 		 */
760 		dot = strchr(p->fts_name, '.');
761 		if (dot && strchr(dot + 1, '.') != NULL)
762 			continue;
763 		read_kld(p->fts_path, p->fts_name);
764 	}
765 	fts_close(ftsp);
766 	return (0);
767 }
768