xref: /freebsd/usr.sbin/config/main.cc (revision ebacd8013fe5f7fdf9f6a5b286f6680dd2891036)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1980, 1993
5  *	The Regents of the University of California.  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. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #ifndef lint
33 static const char copyright[] =
34 "@(#) Copyright (c) 1980, 1993\n\
35 	The Regents of the University of California.  All rights reserved.\n";
36 #endif /* not lint */
37 
38 #ifndef lint
39 #if 0
40 static char sccsid[] = "@(#)main.c	8.1 (Berkeley) 6/6/93";
41 #endif
42 static const char rcsid[] =
43   "$FreeBSD$";
44 #endif /* not lint */
45 
46 #include <sys/types.h>
47 #include <sys/stat.h>
48 #include <sys/file.h>
49 #include <sys/mman.h>
50 #include <sys/param.h>
51 
52 #include <assert.h>
53 #include <ctype.h>
54 #include <dirent.h>
55 #include <err.h>
56 #include <iostream>
57 #include <sstream>
58 #include <stdio.h>
59 #include <string.h>
60 #include <sysexits.h>
61 #include <unistd.h>
62 
63 #include "y.tab.h"
64 #include "config.h"
65 #include "configvers.h"
66 
67 #ifndef TRUE
68 #define TRUE	(1)
69 #endif
70 
71 #ifndef FALSE
72 #define FALSE	(0)
73 #endif
74 
75 #define	CDIR	"../compile/"
76 
77 char	*machinename;
78 char	*machinearch;
79 
80 struct cfgfile_head	cfgfiles;
81 struct cputype_head	cputype;
82 struct opt_head		opt, mkopt, rmopts;
83 struct opt_list_head	otab;
84 struct envvar_head	envvars;
85 struct hint_head	hints;
86 struct includepath_head	includepath;
87 
88 char *	PREFIX;
89 char 	destdir[MAXPATHLEN];
90 char 	srcdir[MAXPATHLEN];
91 
92 int	debugging;
93 int	found_defaults;
94 int	incignore;
95 
96 /*
97  * Preserve old behaviour in INCLUDE_CONFIG_FILE handling (files are included
98  * literally).
99  */
100 int	filebased = 0;
101 int	versreq;
102 
103 static void configfile(void);
104 static void get_srcdir(void);
105 static void usage(void);
106 static void cleanheaders(char *);
107 static void kernconfdump(const char *);
108 static void badversion(void);
109 static void checkversion(void);
110 
111 struct hdr_list {
112 	const char *h_name;
113 	struct hdr_list *h_next;
114 } *htab;
115 
116 static std::stringstream line_buf;
117 
118 /*
119  * Config builds a set of files for building a UNIX
120  * system given a description of the desired system.
121  */
122 int
123 main(int argc, char **argv)
124 {
125 
126 	struct stat buf;
127 	int ch, len;
128 	char *p;
129 	char *kernfile;
130 	struct includepath* ipath;
131 	int printmachine;
132 	bool cust_dest = false;
133 
134 	printmachine = 0;
135 	kernfile = NULL;
136 	SLIST_INIT(&includepath);
137 	SLIST_INIT(&cputype);
138 	SLIST_INIT(&mkopt);
139 	SLIST_INIT(&opt);
140 	SLIST_INIT(&rmopts);
141 	STAILQ_INIT(&cfgfiles);
142 	STAILQ_INIT(&dtab);
143 	STAILQ_INIT(&fntab);
144 	STAILQ_INIT(&ftab);
145 	STAILQ_INIT(&hints);
146 	STAILQ_INIT(&envvars);
147 	while ((ch = getopt(argc, argv, "Cd:gI:mps:Vx:")) != -1)
148 		switch (ch) {
149 		case 'C':
150 			filebased = 1;
151 			break;
152 		case 'd':
153 			if (*destdir == '\0')
154 				strlcpy(destdir, optarg, sizeof(destdir));
155 			else
156 				errx(EXIT_FAILURE, "directory already set");
157 			cust_dest = true;
158 			break;
159 		case 'g':
160 			debugging++;
161 			break;
162 		case 'I':
163 			ipath = (struct includepath *) \
164 			    	calloc(1, sizeof (struct includepath));
165 			if (ipath == NULL)
166 				err(EXIT_FAILURE, "calloc");
167 			ipath->path = optarg;
168 			SLIST_INSERT_HEAD(&includepath, ipath, path_next);
169 			break;
170 		case 'm':
171 			printmachine = 1;
172 			break;
173 		case 's':
174 			if (*srcdir == '\0')
175 				strlcpy(srcdir, optarg, sizeof(srcdir));
176 			else
177 				errx(EXIT_FAILURE, "src directory already set");
178 			break;
179 		case 'V':
180 			printf("%d\n", CONFIGVERS);
181 			exit(0);
182 		case 'x':
183 			kernfile = optarg;
184 			break;
185 		case '?':
186 		default:
187 			usage();
188 		}
189 	argc -= optind;
190 	argv += optind;
191 
192 	if (kernfile != NULL) {
193 		kernconfdump(kernfile);
194 		exit(EXIT_SUCCESS);
195 	}
196 
197 	if (argc != 1)
198 		usage();
199 
200 	PREFIX = *argv;
201 	if (stat(PREFIX, &buf) != 0 || !S_ISREG(buf.st_mode))
202 		err(2, "%s", PREFIX);
203 	if (freopen("DEFAULTS", "r", stdin) != NULL) {
204 		found_defaults = 1;
205 		yyfile = "DEFAULTS";
206 	} else {
207 		if (freopen(PREFIX, "r", stdin) == NULL)
208 			err(2, "%s", PREFIX);
209 		yyfile = PREFIX;
210 	}
211 	if (*destdir != '\0') {
212 		len = strlen(destdir);
213 		while (len > 1 && destdir[len - 1] == '/')
214 			destdir[--len] = '\0';
215 		if (*srcdir == '\0')
216 			get_srcdir();
217 	} else {
218 		strlcpy(destdir, CDIR, sizeof(destdir));
219 		strlcat(destdir, PREFIX, sizeof(destdir));
220 	}
221 
222 	if (yyparse())
223 		exit(3);
224 
225 	/*
226 	 * Ensure that required elements (machine, cpu, ident) are present.
227 	 */
228 	if (machinename == NULL) {
229 		printf("Specify machine type, e.g. ``machine i386''\n");
230 		exit(1);
231 	}
232 	if (ident == NULL) {
233 		printf("no ident line specified\n");
234 		exit(1);
235 	}
236 	if (SLIST_EMPTY(&cputype)) {
237 		printf("cpu type must be specified\n");
238 		exit(1);
239 	}
240 	checkversion();
241 
242 	if (printmachine) {
243 		printf("%s\t%s\n",machinename,machinearch);
244 		exit(0);
245 	}
246 
247 	/*
248 	 * Make CDIR directory, if doing a default destination. Some version
249 	 * control systems delete empty directories and this seemlessly copes.
250 	 */
251 	if (!cust_dest && stat(CDIR, &buf))
252 		if (mkdir(CDIR, 0777))
253 			err(2, "%s", CDIR);
254 	/* Create the compile directory */
255 	p = path((char *)NULL);
256 	if (stat(p, &buf)) {
257 		if (mkdir(p, 0777))
258 			err(2, "%s", p);
259 	} else if (!S_ISDIR(buf.st_mode))
260 		errx(EXIT_FAILURE, "%s isn't a directory", p);
261 
262 	configfile();			/* put config file into kernel*/
263 	options();			/* make options .h files */
264 	makefile();			/* build Makefile */
265 	makeenv();			/* build env.c */
266 	makehints();			/* build hints.c */
267 	headers();			/* make a lot of .h files */
268 	cleanheaders(p);
269 	printf("Kernel build directory is %s\n", p);
270 	printf("Don't forget to do ``make cleandepend && make depend''\n");
271 	exit(0);
272 }
273 
274 /*
275  * get_srcdir
276  *	determine the root of the kernel source tree
277  *	and save that in srcdir.
278  */
279 static void
280 get_srcdir(void)
281 {
282 	struct stat lg, phy;
283 	char *p, *pwd;
284 	int i;
285 
286 	if (realpath("../..", srcdir) == NULL)
287 		err(EXIT_FAILURE, "Unable to find root of source tree");
288 	if ((pwd = getenv("PWD")) != NULL && *pwd == '/' &&
289 	    (pwd = strdup(pwd)) != NULL) {
290 		/* Remove the last two path components. */
291 		for (i = 0; i < 2; i++) {
292 			if ((p = strrchr(pwd, '/')) == NULL) {
293 				free(pwd);
294 				return;
295 			}
296 			*p = '\0';
297 		}
298 		if (stat(pwd, &lg) != -1 && stat(srcdir, &phy) != -1 &&
299 		    lg.st_dev == phy.st_dev && lg.st_ino == phy.st_ino)
300 			strlcpy(srcdir, pwd, MAXPATHLEN);
301 		free(pwd);
302 	}
303 }
304 
305 static void
306 usage(void)
307 {
308 
309 	fprintf(stderr,
310 	    "usage: config [-CgmpV] [-d destdir] [-s srcdir] sysname\n");
311 	fprintf(stderr, "       config -x kernel\n");
312 	exit(EX_USAGE);
313 }
314 
315 static void
316 init_line_buf(void)
317 {
318 
319 	line_buf.str("");
320 }
321 
322 static std::string
323 get_line_buf(void)
324 {
325 
326 	line_buf.flush();
327 	if (!line_buf.good()) {
328 		errx(EXIT_FAILURE, "failed to generate line buffer, "
329 		    "partial line = %s", line_buf.str().c_str());
330 	}
331 
332 	return line_buf.str();
333 }
334 
335 /*
336  * get_word
337  *	returns EOF on end of file
338  *	NULL on end of line
339  *	pointer to the word otherwise
340  */
341 configword
342 get_word(FILE *fp)
343 {
344 	int ch;
345 	int escaped_nl = 0;
346 
347 	init_line_buf();
348 begin:
349 	while ((ch = getc(fp)) != EOF)
350 		if (ch != ' ' && ch != '\t')
351 			break;
352 	if (ch == EOF)
353 		return (configword().eof(true));
354 	if (ch == '\\'){
355 		escaped_nl = 1;
356 		goto begin;
357 	}
358 	if (ch == '\n') {
359 		if (escaped_nl){
360 			escaped_nl = 0;
361 			goto begin;
362 		}
363 		else
364 			return (configword().eol(true));
365 	}
366 	line_buf << (char)ch;
367 	/* Negation operator is a word by itself. */
368 	if (ch == '!') {
369 		return (configword(get_line_buf()));
370 	}
371 	while ((ch = getc(fp)) != EOF) {
372 		if (isspace(ch))
373 			break;
374 		line_buf << (char)ch;
375 	}
376 	if (ch == EOF)
377 		return (configword().eof(true));
378 	(void) ungetc(ch, fp);
379 	return (configword(get_line_buf()));
380 }
381 
382 /*
383  * get_quoted_word
384  *	like get_word but will accept something in double or single quotes
385  *	(to allow embedded spaces).
386  */
387 configword
388 get_quoted_word(FILE *fp)
389 {
390 	int ch;
391 	int escaped_nl = 0;
392 
393 	init_line_buf();
394 begin:
395 	while ((ch = getc(fp)) != EOF)
396 		if (ch != ' ' && ch != '\t')
397 			break;
398 	if (ch == EOF)
399 		return (configword().eof(true));
400 	if (ch == '\\'){
401 		escaped_nl = 1;
402 		goto begin;
403 	}
404 	if (ch == '\n') {
405 		if (escaped_nl){
406 			escaped_nl = 0;
407 			goto begin;
408 		}
409 		else
410 			return (configword().eol(true));
411 	}
412 	if (ch == '"' || ch == '\'') {
413 		int quote = ch;
414 
415 		escaped_nl = 0;
416 		while ((ch = getc(fp)) != EOF) {
417 			if (ch == quote && !escaped_nl)
418 				break;
419 			if (ch == '\n' && !escaped_nl) {
420 				printf("config: missing quote reading `%s'\n",
421 					get_line_buf().c_str());
422 				exit(2);
423 			}
424 			if (ch == '\\' && !escaped_nl) {
425 				escaped_nl = 1;
426 				continue;
427 			}
428 			if (ch != quote && escaped_nl)
429 				line_buf << "\\";
430 			line_buf << (char)ch;
431 			escaped_nl = 0;
432 		}
433 	} else {
434 		line_buf << (char)ch;
435 		while ((ch = getc(fp)) != EOF) {
436 			if (isspace(ch))
437 				break;
438 			line_buf << (char)ch;
439 		}
440 		if (ch != EOF)
441 			(void) ungetc(ch, fp);
442 	}
443 	if (ch == EOF)
444 		return (configword().eof(true));
445 	return (configword(get_line_buf()));
446 }
447 
448 /*
449  * prepend the path to a filename
450  */
451 char *
452 path(const char *file)
453 {
454 	char *cp = NULL;
455 
456 	if (file)
457 		asprintf(&cp, "%s/%s", destdir, file);
458 	else
459 		cp = strdup(destdir);
460 	if (cp == NULL)
461 		err(EXIT_FAILURE, "malloc");
462 	return (cp);
463 }
464 
465 /*
466  * Generate configuration file based on actual settings. With this mode, user
467  * will be able to obtain and build conifguration file with one command.
468  */
469 static void
470 configfile_dynamic(std::ostringstream &cfg)
471 {
472 	struct cputype *cput;
473 	struct device *d;
474 	struct opt *ol;
475 	char *lend;
476 	unsigned int i;
477 
478 	asprintf(&lend, "\\n\\\n");
479 	assert(lend != NULL);
480 	cfg << "options\t" << OPT_AUTOGEN << lend;
481 	cfg << "ident\t" << ident << lend;
482 	cfg << "machine\t" << machinename << lend;
483 	SLIST_FOREACH(cput, &cputype, cpu_next)
484 		cfg << "cpu\t" << cput->cpu_name << lend;
485 	SLIST_FOREACH(ol, &mkopt, op_next)
486 		cfg << "makeoptions\t" << ol->op_name << '=' <<
487 		    ol->op_value << lend;
488 	SLIST_FOREACH(ol, &opt, op_next) {
489 		if (strncmp(ol->op_name, "DEV_", 4) == 0)
490 			continue;
491 		cfg << "options\t" << ol->op_name;
492 		if (ol->op_value != NULL) {
493 			cfg << '=';
494 			for (i = 0; i < strlen(ol->op_value); i++) {
495 				if (ol->op_value[i] == '"')
496 					cfg << '\\' << ol->op_value[i];
497 				else
498 					cfg << ol->op_value[i];
499 			}
500 		}
501 
502 		cfg << lend;
503 	}
504 	/*
505 	 * Mark this file as containing everything we need.
506 	 */
507 	STAILQ_FOREACH(d, &dtab, d_next)
508 		cfg << "device\t" << d->d_name << lend;
509 	free(lend);
510 }
511 
512 /*
513  * Generate file from the configuration files.
514  */
515 static void
516 configfile_filebased(std::ostringstream &cfg)
517 {
518 	FILE *cff;
519 	struct cfgfile *cf;
520 	int i;
521 
522 	/*
523 	 * Try to read all configuration files. Since those will be present as
524 	 * C string in the macro, we have to slash their ends then the line
525 	 * wraps.
526 	 */
527 	STAILQ_FOREACH(cf, &cfgfiles, cfg_next) {
528 		cff = fopen(cf->cfg_path, "r");
529 		if (cff == NULL) {
530 			warn("Couldn't open file %s", cf->cfg_path);
531 			continue;
532 		}
533 		while ((i = getc(cff)) != EOF) {
534 			if (i == '\n')
535 				cfg << "\\n\\\n";
536 			else if (i == '"' || i == '\'')
537 				cfg << '\\' << i;
538 			else
539 				cfg << i;
540 		}
541 		fclose(cff);
542 	}
543 }
544 
545 static void
546 configfile(void)
547 {
548 	FILE *fo;
549 	std::ostringstream cfg;
550 	char *p;
551 
552 	/* Add main configuration file to the list of files to be included */
553 	cfgfile_add(PREFIX);
554 	p = path("config.c.new");
555 	fo = fopen(p, "w");
556 	if (!fo)
557 		err(2, "%s", p);
558 	free(p);
559 
560 	if (filebased) {
561 		/* Is needed, can be used for backward compatibility. */
562 		configfile_filebased(cfg);
563 	} else {
564 		configfile_dynamic(cfg);
565 	}
566 
567 	cfg.flush();
568 	/*
569 	 * We print first part of the template, replace our tag with
570 	 * configuration files content and later continue writing our
571 	 * template.
572 	 */
573 	p = strstr(kernconfstr, KERNCONFTAG);
574 	if (p == NULL)
575 		errx(EXIT_FAILURE, "Something went terribly wrong!");
576 	*p = '\0';
577 	fprintf(fo, "%s", kernconfstr);
578 	fprintf(fo, "%s", cfg.str().c_str());
579 	p += strlen(KERNCONFTAG);
580 	fprintf(fo, "%s", p);
581 	fclose(fo);
582 	moveifchanged("config.c.new", "config.c");
583 	cfgfile_removeall();
584 }
585 
586 /*
587  * moveifchanged --
588  *	compare two files; rename if changed.
589  */
590 void
591 moveifchanged(const char *from_name, const char *to_name)
592 {
593 	char *p, *q;
594 	char *from_path, *to_path;
595 	int changed;
596 	size_t tsize;
597 	struct stat from_sb, to_sb;
598 	int from_fd, to_fd;
599 
600 	changed = 0;
601 
602 	from_path = path(from_name);
603 	to_path = path(to_name);
604 	if ((from_fd = open(from_path, O_RDONLY)) < 0)
605 		err(EX_OSERR, "moveifchanged open(%s)", from_name);
606 
607 	if ((to_fd = open(to_path, O_RDONLY)) < 0)
608 		changed++;
609 
610 	if (!changed && fstat(from_fd, &from_sb) < 0)
611 		err(EX_OSERR, "moveifchanged fstat(%s)", from_path);
612 
613 	if (!changed && fstat(to_fd, &to_sb) < 0)
614 		err(EX_OSERR, "moveifchanged fstat(%s)", to_path);
615 
616 	if (!changed && from_sb.st_size != to_sb.st_size)
617 		changed++;
618 
619 	if (!changed) {
620 		tsize = (size_t)from_sb.st_size;
621 
622 		p = (char *)mmap(NULL, tsize, PROT_READ, MAP_SHARED, from_fd,
623 		    (off_t)0);
624 		if (p == MAP_FAILED)
625 			err(EX_OSERR, "mmap %s", from_path);
626 		q = (char *)mmap(NULL, tsize, PROT_READ, MAP_SHARED, to_fd,
627 		    (off_t)0);
628 		if (q == MAP_FAILED)
629 			err(EX_OSERR, "mmap %s", to_path);
630 
631 		changed = memcmp(p, q, tsize);
632 		munmap(p, tsize);
633 		munmap(q, tsize);
634 	}
635 
636 	if (changed) {
637 		if (rename(from_path, to_path) < 0)
638 			err(EX_OSERR, "rename(%s, %s)", from_path, to_path);
639 	} else {
640 		if (unlink(from_path) < 0)
641 			err(EX_OSERR, "unlink(%s)", from_path);
642 	}
643 
644 	close(from_fd);
645 	if (to_fd >= 0)
646 		close(to_fd);
647 
648 	free(from_path);
649 	free(to_path);
650 }
651 
652 static void
653 cleanheaders(char *p)
654 {
655 	DIR *dirp;
656 	struct dirent *dp;
657 	struct file_list *fl;
658 	struct hdr_list *hl;
659 	size_t len;
660 
661 	remember("y.tab.h");
662 	remember("setdefs.h");
663 	STAILQ_FOREACH(fl, &ftab, f_next)
664 		remember(fl->f_fn);
665 
666 	/*
667 	 * Scan the build directory and clean out stuff that looks like
668 	 * it might have been a leftover NFOO header, etc.
669 	 */
670 	if ((dirp = opendir(p)) == NULL)
671 		err(EX_OSERR, "opendir %s", p);
672 	while ((dp = readdir(dirp)) != NULL) {
673 		len = strlen(dp->d_name);
674 		/* Skip non-headers */
675 		if (len < 2 || dp->d_name[len - 2] != '.' ||
676 		    dp->d_name[len - 1] != 'h')
677 			continue;
678 		/* Skip special stuff, eg: bus_if.h, but check opt_*.h */
679 		if (strchr(dp->d_name, '_') &&
680 		    strncmp(dp->d_name, "opt_", 4) != 0)
681 			continue;
682 		/* Check if it is a target file */
683 		for (hl = htab; hl != NULL; hl = hl->h_next) {
684 			if (eq(dp->d_name, hl->h_name)) {
685 				break;
686 			}
687 		}
688 		if (hl)
689 			continue;
690 		printf("Removing stale header: %s\n", dp->d_name);
691 		p = path(dp->d_name);
692 		if (unlink(p) == -1)
693 			warn("unlink %s", dp->d_name);
694 		free(p);
695 	}
696 	(void)closedir(dirp);
697 }
698 
699 void
700 remember(const char *file)
701 {
702 	const char *s;
703 	struct hdr_list *hl;
704 
705 	if ((s = strrchr(file, '/')) != NULL)
706 		s = ns(s + 1);
707 	else
708 		s = ns(file);
709 
710 	if (strchr(s, '_') && strncmp(s, "opt_", 4) != 0) {
711 		free(__DECONST(char *, s));
712 		return;
713 	}
714 	for (hl = htab; hl != NULL; hl = hl->h_next) {
715 		if (eq(s, hl->h_name)) {
716 			free(__DECONST(char *, s));
717 			return;
718 		}
719 	}
720 	hl = (struct hdr_list *)calloc(1, sizeof(*hl));
721 	if (hl == NULL)
722 		err(EXIT_FAILURE, "calloc");
723 	hl->h_name = s;
724 	hl->h_next = htab;
725 	htab = hl;
726 }
727 
728 /*
729  * This one is quick hack. Will be probably moved to elf(3) interface.
730  * It takes kernel configuration file name, passes it as an argument to
731  * elfdump -a, which output is parsed by some UNIX tools...
732  */
733 static void
734 kernconfdump(const char *file)
735 {
736 	struct stat st;
737 	FILE *fp, *pp;
738 	int error, osz, r;
739 	size_t i, off, size, t1, t2, align;
740 	char *cmd, *o;
741 
742 	r = open(file, O_RDONLY);
743 	if (r == -1)
744 		err(EXIT_FAILURE, "Couldn't open file '%s'", file);
745 	error = fstat(r, &st);
746 	if (error == -1)
747 		err(EXIT_FAILURE, "fstat() failed");
748 	if (S_ISDIR(st.st_mode))
749 		errx(EXIT_FAILURE, "'%s' is a directory", file);
750 	fp = fdopen(r, "r");
751 	if (fp == NULL)
752 		err(EXIT_FAILURE, "fdopen() failed");
753 	osz = 1024;
754 	o = (char *)calloc(1, osz);
755 	if (o == NULL)
756 		err(EXIT_FAILURE, "Couldn't allocate memory");
757 	/* ELF note section header. */
758 	asprintf(&cmd, "/usr/bin/elfdump -c %s | grep -A 8 kern_conf"
759 	    "| tail -5 | cut -d ' ' -f 2 | paste - - - - -", file);
760 	if (cmd == NULL)
761 		errx(EXIT_FAILURE, "asprintf() failed");
762 	pp = popen(cmd, "r");
763 	if (pp == NULL)
764 		errx(EXIT_FAILURE, "popen() failed");
765 	free(cmd);
766 	(void)fread(o, osz, 1, pp);
767 	pclose(pp);
768 	r = sscanf(o, "%zu%zu%zu%zu%zu", &off, &size, &t1, &t2, &align);
769 	free(o);
770 	if (size > SIZE_MAX - off || off + size > (size_t)st.st_size)
771 		errx(EXIT_FAILURE, "%s: incoherent ELF headers", file);
772 	if (r != 5)
773 		errx(EXIT_FAILURE, "File %s doesn't contain configuration "
774 		    "file. Either unsupported, or not compiled with "
775 		    "INCLUDE_CONFIG_FILE", file);
776 	r = fseek(fp, off, SEEK_CUR);
777 	if (r != 0)
778 		err(EXIT_FAILURE, "fseek() failed");
779 	for (i = 0; i < size; i++) {
780 		r = fgetc(fp);
781 		if (r == EOF)
782 			break;
783 		if (r == '\0') {
784 			assert(i == size - 1 &&
785 			    ("\\0 found in the middle of a file"));
786 			break;
787 		}
788 		fputc(r, stdout);
789 	}
790 	fclose(fp);
791 }
792 
793 static void
794 badversion(void)
795 {
796 	fprintf(stderr, "ERROR: version of config(8) does not match kernel!\n");
797 	fprintf(stderr, "config version = %d, ", CONFIGVERS);
798 	fprintf(stderr, "version required = %d\n\n", versreq);
799 	fprintf(stderr, "Make sure that /usr/src/usr.sbin/config is in sync\n");
800 	fprintf(stderr, "with your /usr/src/sys and install a new config binary\n");
801 	fprintf(stderr, "before trying this again.\n\n");
802 	fprintf(stderr, "If running the new config fails check your config\n");
803 	fprintf(stderr, "file against the GENERIC or LINT config files for\n");
804 	fprintf(stderr, "changes in config syntax, or option/device naming\n");
805 	fprintf(stderr, "conventions\n\n");
806 	exit(1);
807 }
808 
809 static void
810 checkversion(void)
811 {
812 	FILE *ifp;
813 	char line[BUFSIZ];
814 
815 	ifp = open_makefile_template();
816 	while (fgets(line, BUFSIZ, ifp) != 0) {
817 		if (*line != '%')
818 			continue;
819 		if (strncmp(line, "%VERSREQ=", 9) != 0)
820 			continue;
821 		versreq = atoi(line + 9);
822 		if (MAJOR_VERS(versreq) == MAJOR_VERS(CONFIGVERS) &&
823 		    versreq <= CONFIGVERS)
824 			continue;
825 		badversion();
826 	}
827 	fclose(ifp);
828 }
829