xref: /freebsd/contrib/file/src/file.c (revision 994297b01b98816bea1abf45ae4bac1bc69ee7a0)
1 /*
2  * Copyright (c) Ian F. Darwin 1986-1995.
3  * Software written by Ian F. Darwin and others;
4  * maintained 1995-present by Christos Zoulas and others.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice immediately at the beginning of the file, without modification,
11  *    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  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
20  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 /*
29  * file - find type of a file or files - main program.
30  */
31 
32 #include "file.h"
33 
34 #ifndef	lint
35 FILE_RCSID("@(#)$File: file.c,v 1.190 2021/09/24 14:14:26 christos Exp $")
36 #endif	/* lint */
37 
38 #include "magic.h"
39 
40 #include <stdlib.h>
41 #include <unistd.h>
42 #include <string.h>
43 #ifdef RESTORE_TIME
44 # if (__COHERENT__ >= 0x420)
45 #  include <sys/utime.h>
46 # else
47 #  ifdef USE_UTIMES
48 #   include <sys/time.h>
49 #  else
50 #   include <utime.h>
51 #  endif
52 # endif
53 #endif
54 #ifdef HAVE_UNISTD_H
55 #include <unistd.h>	/* for read() */
56 #endif
57 #ifdef HAVE_WCHAR_H
58 #include <wchar.h>
59 #endif
60 
61 #if defined(HAVE_GETOPT_H) && defined(HAVE_STRUCT_OPTION)
62 # include <getopt.h>
63 # ifndef HAVE_GETOPT_LONG
64 int getopt_long(int, char * const *, const char *,
65     const struct option *, int *);
66 # endif
67 # else
68 #  include "mygetopt.h"
69 #endif
70 
71 #ifdef S_IFLNK
72 # define IFLNK_h "h"
73 # define IFLNK_L "L"
74 #else
75 # define IFLNK_h ""
76 # define IFLNK_L ""
77 #endif
78 
79 #define FILE_FLAGS	"bcCdE" IFLNK_h "ik" IFLNK_L "lNnprsSvzZ0"
80 #define OPTSTRING	"bcCde:Ef:F:hiklLm:nNpP:rsSvzZ0"
81 
82 # define USAGE  \
83     "Usage: %s [-" FILE_FLAGS "] [--apple] [--extension] [--mime-encoding]\n" \
84     "            [--mime-type] [-e <testname>] [-F <separator>] " \
85     " [-f <namefile>]\n" \
86     "            [-m <magicfiles>] [-P <parameter=value>] [--exclude-quiet]\n" \
87     "            <file> ...\n" \
88     "       %s -C [-m <magicfiles>]\n" \
89     "       %s [--help]\n"
90 
91 private int 		/* Global command-line options 		*/
92 	bflag = 0,	/* brief output format	 		*/
93 	nopad = 0,	/* Don't pad output			*/
94 	nobuffer = 0,   /* Do not buffer stdout 		*/
95 	nulsep = 0;	/* Append '\0' to the separator		*/
96 
97 private const char *separator = ":";	/* Default field separator	*/
98 private const struct option long_options[] = {
99 #define OPT_HELP		1
100 #define OPT_APPLE		2
101 #define OPT_EXTENSIONS		3
102 #define OPT_MIME_TYPE		4
103 #define OPT_MIME_ENCODING	5
104 #define OPT_EXCLUDE_QUIET	6
105 #define OPT(shortname, longname, opt, def, doc)		\
106     {longname, opt, NULL, shortname},
107 #define OPT_LONGONLY(longname, opt, def, doc, id)	\
108     {longname, opt, NULL, id},
109 #include "file_opts.h"
110 #undef OPT
111 #undef OPT_LONGONLY
112     {0, 0, NULL, 0}
113     };
114 
115 private const struct {
116 	const char *name;
117 	int value;
118 } nv[] = {
119 	{ "apptype",	MAGIC_NO_CHECK_APPTYPE },
120 	{ "ascii",	MAGIC_NO_CHECK_ASCII },
121 	{ "cdf",	MAGIC_NO_CHECK_CDF },
122 	{ "compress",	MAGIC_NO_CHECK_COMPRESS },
123 	{ "csv",	MAGIC_NO_CHECK_CSV },
124 	{ "elf",	MAGIC_NO_CHECK_ELF },
125 	{ "encoding",	MAGIC_NO_CHECK_ENCODING },
126 	{ "soft",	MAGIC_NO_CHECK_SOFT },
127 	{ "tar",	MAGIC_NO_CHECK_TAR },
128 	{ "json",	MAGIC_NO_CHECK_JSON },
129 	{ "text",	MAGIC_NO_CHECK_TEXT },	/* synonym for ascii */
130 	{ "tokens",	MAGIC_NO_CHECK_TOKENS }, /* OBSOLETE: ignored for backwards compatibility */
131 };
132 
133 private struct {
134 	const char *name;
135 	size_t value;
136 	size_t def;
137 	const char *desc;
138 	int tag;
139 	int set;
140 } pm[] = {
141 	{ "bytes", 0, FILE_BYTES_MAX, "max bytes to look inside file",
142 	    MAGIC_PARAM_BYTES_MAX, 0 },
143 	{ "elf_notes", 0, FILE_ELF_NOTES_MAX, "max ELF notes processed",
144 	    MAGIC_PARAM_ELF_NOTES_MAX, 0 },
145 	{ "elf_phnum", 0, FILE_ELF_PHNUM_MAX, "max ELF prog sections processed",
146 	    MAGIC_PARAM_ELF_PHNUM_MAX, 0 },
147 	{ "elf_shnum", 0, FILE_ELF_SHNUM_MAX, "max ELF sections processed",
148 	    MAGIC_PARAM_ELF_SHNUM_MAX, 0 },
149 	{ "encoding", 0, FILE_ENCODING_MAX, "max bytes to scan for encoding",
150 	    MAGIC_PARAM_ENCODING_MAX, 0 },
151 	{ "indir", 0, FILE_INDIR_MAX, "recursion limit for indirection",
152 	    MAGIC_PARAM_INDIR_MAX, 0 },
153 	{ "name", 0, FILE_NAME_MAX, "use limit for name/use magic",
154 	    MAGIC_PARAM_NAME_MAX, 0 },
155 	{ "regex", 0, FILE_REGEX_MAX, "length limit for REGEX searches",
156 	    MAGIC_PARAM_REGEX_MAX, 0 },
157 };
158 
159 private int posixly;
160 
161 #ifdef __dead
162 __dead
163 #endif
164 private void usage(void);
165 private void docprint(const char *, int);
166 #ifdef __dead
167 __dead
168 #endif
169 private void help(void);
170 
171 private int unwrap(struct magic_set *, const char *);
172 private int process(struct magic_set *ms, const char *, int);
173 private struct magic_set *load(const char *, int);
174 private void setparam(const char *);
175 private void applyparam(magic_t);
176 
177 
178 /*
179  * main - parse arguments and handle options
180  */
181 int
182 main(int argc, char *argv[])
183 {
184 	int c;
185 	size_t i;
186 	int action = 0, didsomefiles = 0, errflg = 0;
187 	int flags = 0, e = 0;
188 #ifdef HAVE_LIBSECCOMP
189 	int sandbox = 1;
190 #endif
191 	struct magic_set *magic = NULL;
192 	int longindex;
193 	const char *magicfile = NULL;		/* where the magic is	*/
194 	char *progname;
195 
196 	/* makes islower etc work for other langs */
197 	(void)setlocale(LC_CTYPE, "");
198 
199 #ifdef __EMX__
200 	/* sh-like wildcard expansion! Shouldn't hurt at least ... */
201 	_wildcard(&argc, &argv);
202 #endif
203 
204 	if ((progname = strrchr(argv[0], '/')) != NULL)
205 		progname++;
206 	else
207 		progname = argv[0];
208 
209 	file_setprogname(progname);
210 
211 
212 #ifdef S_IFLNK
213 	posixly = getenv("POSIXLY_CORRECT") != NULL;
214 	flags |=  posixly ? MAGIC_SYMLINK : 0;
215 #endif
216 	while ((c = getopt_long(argc, argv, OPTSTRING, long_options,
217 	    &longindex)) != -1)
218 		switch (c) {
219 		case OPT_HELP:
220 			help();
221 			break;
222 		case OPT_APPLE:
223 			flags |= MAGIC_APPLE;
224 			break;
225 		case OPT_EXTENSIONS:
226 			flags |= MAGIC_EXTENSION;
227 			break;
228 		case OPT_MIME_TYPE:
229 			flags |= MAGIC_MIME_TYPE;
230 			break;
231 		case OPT_MIME_ENCODING:
232 			flags |= MAGIC_MIME_ENCODING;
233 			break;
234 		case '0':
235 			nulsep++;
236 			break;
237 		case 'b':
238 			bflag++;
239 			break;
240 		case 'c':
241 			action = FILE_CHECK;
242 			break;
243 		case 'C':
244 			action = FILE_COMPILE;
245 			break;
246 		case 'd':
247 			flags |= MAGIC_DEBUG|MAGIC_CHECK;
248 			break;
249 		case 'E':
250 			flags |= MAGIC_ERROR;
251 			break;
252 		case 'e':
253 		case OPT_EXCLUDE_QUIET:
254 			for (i = 0; i < __arraycount(nv); i++)
255 				if (strcmp(nv[i].name, optarg) == 0)
256 					break;
257 
258 			if (i == __arraycount(nv)) {
259 				if (c != OPT_EXCLUDE_QUIET)
260 					errflg++;
261 			} else
262 				flags |= nv[i].value;
263 			break;
264 
265 		case 'f':
266 			if(action)
267 				usage();
268 			if (magic == NULL)
269 				if ((magic = load(magicfile, flags)) == NULL)
270 					return 1;
271 			applyparam(magic);
272 			e |= unwrap(magic, optarg);
273 			++didsomefiles;
274 			break;
275 		case 'F':
276 			separator = optarg;
277 			break;
278 		case 'i':
279 			flags |= MAGIC_MIME;
280 			break;
281 		case 'k':
282 			flags |= MAGIC_CONTINUE;
283 			break;
284 		case 'l':
285 			action = FILE_LIST;
286 			break;
287 		case 'm':
288 			magicfile = optarg;
289 			break;
290 		case 'n':
291 			++nobuffer;
292 			break;
293 		case 'N':
294 			++nopad;
295 			break;
296 #if defined(HAVE_UTIME) || defined(HAVE_UTIMES)
297 		case 'p':
298 			flags |= MAGIC_PRESERVE_ATIME;
299 			break;
300 #endif
301 		case 'P':
302 			setparam(optarg);
303 			break;
304 		case 'r':
305 			flags |= MAGIC_RAW;
306 			break;
307 		case 's':
308 			flags |= MAGIC_DEVICES;
309 			break;
310 		case 'S':
311 #ifdef HAVE_LIBSECCOMP
312 			sandbox = 0;
313 #endif
314 			break;
315 		case 'v':
316 			if (magicfile == NULL)
317 				magicfile = magic_getpath(magicfile, action);
318 			(void)fprintf(stdout, "%s-%s\n", file_getprogname(),
319 			    VERSION);
320 			(void)fprintf(stdout, "magic file from %s\n",
321 			    magicfile);
322 #ifdef HAVE_LIBSECCOMP
323 			(void)fprintf(stdout, "seccomp support included\n");
324 #endif
325 			return 0;
326 		case 'z':
327 			flags |= MAGIC_COMPRESS;
328 			break;
329 
330 		case 'Z':
331 			flags |= MAGIC_COMPRESS|MAGIC_COMPRESS_TRANSP;
332 			break;
333 #ifdef S_IFLNK
334 		case 'L':
335 			flags |= MAGIC_SYMLINK;
336 			break;
337 		case 'h':
338 			flags &= ~MAGIC_SYMLINK;
339 			break;
340 #endif
341 		case '?':
342 		default:
343 			errflg++;
344 			break;
345 		}
346 
347 	if (errflg) {
348 		usage();
349 	}
350 	if (e)
351 		return e;
352 
353 #ifdef HAVE_LIBSECCOMP
354 #if 0
355 	if (sandbox && enable_sandbox_basic() == -1)
356 #else
357 	if (sandbox && enable_sandbox_full() == -1)
358 #endif
359 		file_err(EXIT_FAILURE, "SECCOMP initialisation failed");
360 #endif /* HAVE_LIBSECCOMP */
361 
362 	if (MAGIC_VERSION != magic_version())
363 		file_warnx("Compiled magic version [%d] "
364 		    "does not match with shared library magic version [%d]\n",
365 		    MAGIC_VERSION, magic_version());
366 
367 	switch(action) {
368 	case FILE_CHECK:
369 	case FILE_COMPILE:
370 	case FILE_LIST:
371 		/*
372 		 * Don't try to check/compile ~/.magic unless we explicitly
373 		 * ask for it.
374 		 */
375 		magic = magic_open(flags|MAGIC_CHECK);
376 		if (magic == NULL) {
377 			file_warn("Can't create magic");
378 			return 1;
379 		}
380 
381 
382 		switch(action) {
383 		case FILE_CHECK:
384 			c = magic_check(magic, magicfile);
385 			break;
386 		case FILE_COMPILE:
387 			c = magic_compile(magic, magicfile);
388 			break;
389 		case FILE_LIST:
390 			c = magic_list(magic, magicfile);
391 			break;
392 		default:
393 			abort();
394 		}
395 		if (c == -1) {
396 			file_warnx("%s", magic_error(magic));
397 			e = 1;
398 			goto out;
399 		}
400 		goto out;
401 	default:
402 		if (magic == NULL)
403 			if ((magic = load(magicfile, flags)) == NULL)
404 				return 1;
405 		applyparam(magic);
406 	}
407 
408 	if (optind == argc) {
409 		if (!didsomefiles)
410 			usage();
411 	}
412 	else {
413 		size_t j, wid, nw;
414 		for (wid = 0, j = CAST(size_t, optind); j < CAST(size_t, argc);
415 		    j++) {
416 			nw = file_mbswidth(argv[j]);
417 			if (nw > wid)
418 				wid = nw;
419 		}
420 		/*
421 		 * If bflag is only set twice, set it depending on
422 		 * number of files [this is undocumented, and subject to change]
423 		 */
424 		if (bflag == 2) {
425 			bflag = optind >= argc - 1;
426 		}
427 		for (; optind < argc; optind++)
428 			e |= process(magic, argv[optind], wid);
429 	}
430 
431 out:
432 	if (magic)
433 		magic_close(magic);
434 	return e;
435 }
436 
437 private void
438 applyparam(magic_t magic)
439 {
440 	size_t i;
441 
442 	for (i = 0; i < __arraycount(pm); i++) {
443 		if (!pm[i].set)
444 			continue;
445 		if (magic_setparam(magic, pm[i].tag, &pm[i].value) == -1)
446 			file_err(EXIT_FAILURE, "Can't set %s", pm[i].name);
447 	}
448 }
449 
450 private void
451 setparam(const char *p)
452 {
453 	size_t i;
454 	char *s;
455 
456 	if ((s = strchr(p, '=')) == NULL)
457 		goto badparm;
458 
459 	for (i = 0; i < __arraycount(pm); i++) {
460 		if (strncmp(p, pm[i].name, s - p) != 0)
461 			continue;
462 		pm[i].value = atoi(s + 1);
463 		pm[i].set = 1;
464 		return;
465 	}
466 badparm:
467 	file_errx(EXIT_FAILURE, "Unknown param %s", p);
468 }
469 
470 private struct magic_set *
471 /*ARGSUSED*/
472 load(const char *magicfile, int flags)
473 {
474 	struct magic_set *magic = magic_open(flags);
475 	const char *e;
476 
477 	if (magic == NULL) {
478 		file_warn("Can't create magic");
479 		return NULL;
480 	}
481 	if (magic_load(magic, magicfile) == -1) {
482 		file_warn("%s", magic_error(magic));
483 		magic_close(magic);
484 		return NULL;
485 	}
486 	if ((e = magic_error(magic)) != NULL)
487 		file_warn("%s", e);
488 	return magic;
489 }
490 
491 /*
492  * unwrap -- read a file of filenames, do each one.
493  */
494 private int
495 unwrap(struct magic_set *ms, const char *fn)
496 {
497 	FILE *f;
498 	ssize_t len;
499 	char *line = NULL;
500 	size_t llen = 0;
501 	int wid = 0, cwid;
502 	int e = 0;
503 
504 	if (strcmp("-", fn) == 0) {
505 		f = stdin;
506 		wid = 1;
507 	} else {
508 		if ((f = fopen(fn, "r")) == NULL) {
509 			file_warn("Cannot open `%s'", fn);
510 			return 1;
511 		}
512 
513 		while ((len = getline(&line, &llen, f)) > 0) {
514 			if (line[len - 1] == '\n')
515 				line[len - 1] = '\0';
516 			cwid = file_mbswidth(line);
517 			if (cwid > wid)
518 				wid = cwid;
519 		}
520 
521 		rewind(f);
522 	}
523 
524 	while ((len = getline(&line, &llen, f)) > 0) {
525 		if (line[len - 1] == '\n')
526 			line[len - 1] = '\0';
527 		e |= process(ms, line, wid);
528 	}
529 
530 	free(line);
531 	(void)fclose(f);
532 	return e;
533 }
534 
535 /*
536  * Called for each input file on the command line (or in a list of files)
537  */
538 private int
539 process(struct magic_set *ms, const char *inname, int wid)
540 {
541 	const char *type, c = nulsep > 1 ? '\0' : '\n';
542 	int std_in = strcmp(inname, "-") == 0;
543 
544 	if (wid > 0 && !bflag) {
545 		(void)printf("%s", std_in ? "/dev/stdin" : inname);
546 		if (nulsep)
547 			(void)putc('\0', stdout);
548 		if (nulsep < 2) {
549 			(void)printf("%s", separator);
550 			(void)printf("%*s ", CAST(int, nopad ? 0
551 			    : (wid - file_mbswidth(inname))), "");
552 		}
553 	}
554 
555 	type = magic_file(ms, std_in ? NULL : inname);
556 
557 	if (type == NULL) {
558 		(void)printf("ERROR: %s%c", magic_error(ms), c);
559 	} else {
560 		(void)printf("%s%c", type, c);
561 	}
562 	if (nobuffer)
563 		(void)fflush(stdout);
564 	return type == NULL;
565 }
566 
567 protected size_t
568 file_mbswidth(const char *s)
569 {
570 #if defined(HAVE_WCHAR_H) && defined(HAVE_MBRTOWC) && defined(HAVE_WCWIDTH)
571 	size_t bytesconsumed, old_n, n, width = 0;
572 	mbstate_t state;
573 	wchar_t nextchar;
574 	(void)memset(&state, 0, sizeof(mbstate_t));
575 	old_n = n = strlen(s);
576 
577 	while (n > 0) {
578 		bytesconsumed = mbrtowc(&nextchar, s, n, &state);
579 		if (bytesconsumed == CAST(size_t, -1) ||
580 		    bytesconsumed == CAST(size_t, -2)) {
581 			/* Something went wrong, return something reasonable */
582 			return old_n;
583 		}
584 		if (s[0] == '\n') {
585 			/*
586 			 * do what strlen() would do, so that caller
587 			 * is always right
588 			 */
589 			width++;
590 		} else {
591 			int w = wcwidth(nextchar);
592 			if (w > 0)
593 				width += w;
594 		}
595 
596 		s += bytesconsumed, n -= bytesconsumed;
597 	}
598 	return width;
599 #else
600 	return strlen(s);
601 #endif
602 }
603 
604 private void
605 usage(void)
606 {
607 	const char *pn = file_getprogname();
608 	(void)fprintf(stderr, USAGE, pn, pn, pn);
609 	exit(EXIT_FAILURE);
610 }
611 
612 private void
613 defprint(int def)
614 {
615 	if (!def)
616 		return;
617 	if (((def & 1) && posixly) || ((def & 2) && !posixly))
618 		fprintf(stdout, " (default)");
619 	fputc('\n', stdout);
620 }
621 
622 private void
623 docprint(const char *opts, int def)
624 {
625 	size_t i;
626 	int comma, pad;
627 	char *sp, *p;
628 
629 	p = strchr(opts, '%');
630 	if (p == NULL) {
631 		fprintf(stdout, "%s", opts);
632 		defprint(def);
633 		return;
634 	}
635 
636 	for (sp = p - 1; sp > opts && *sp == ' '; sp--)
637 		continue;
638 
639 	fprintf(stdout, "%.*s", CAST(int, p - opts), opts);
640 	pad = (int)CAST(int, p - sp - 1);
641 
642 	switch (*++p) {
643 	case 'e':
644 		comma = 0;
645 		for (i = 0; i < __arraycount(nv); i++) {
646 			fprintf(stdout, "%s%s", comma++ ? ", " : "", nv[i].name);
647 			if (i && i % 5 == 0 && i != __arraycount(nv) - 1) {
648 				fprintf(stdout, ",\n%*s", pad, "");
649 				comma = 0;
650 			}
651 		}
652 		break;
653 	case 'P':
654 		for (i = 0; i < __arraycount(pm); i++) {
655 			fprintf(stdout, "%9s %7zu %s", pm[i].name, pm[i].def,
656 			    pm[i].desc);
657 			if (i != __arraycount(pm) - 1)
658 				fprintf(stdout, "\n%*s", pad, "");
659 		}
660 		break;
661 	default:
662 		file_errx(EXIT_FAILURE, "Unknown escape `%c' in long options",
663 		   *p);
664 		break;
665 	}
666 	fprintf(stdout, "%s", opts + (p - opts) + 1);
667 
668 }
669 
670 private void
671 help(void)
672 {
673 	(void)fputs(
674 "Usage: file [OPTION...] [FILE...]\n"
675 "Determine type of FILEs.\n"
676 "\n", stdout);
677 #define OPT(shortname, longname, opt, def, doc)      \
678 	fprintf(stdout, "  -%c, --" longname, shortname), \
679 	docprint(doc, def);
680 #define OPT_LONGONLY(longname, opt, def, doc, id)    	\
681 	fprintf(stdout, "      --" longname),	\
682 	docprint(doc, def);
683 #include "file_opts.h"
684 #undef OPT
685 #undef OPT_LONGONLY
686 	fprintf(stdout, "\nReport bugs to https://bugs.astron.com/\n");
687 	exit(EXIT_SUCCESS);
688 }
689 
690 private const char *file_progname;
691 
692 protected void
693 file_setprogname(const char *progname)
694 {
695 	file_progname = progname;
696 }
697 
698 protected const char *
699 file_getprogname(void)
700 {
701 	return file_progname;
702 }
703 
704 protected void
705 file_err(int e, const char *fmt, ...)
706 {
707 	va_list ap;
708 	int se = errno;
709 
710 	va_start(ap, fmt);
711 	fprintf(stderr, "%s: ", file_progname);
712 	vfprintf(stderr, fmt, ap);
713 	va_end(ap);
714 	if (se)
715 		fprintf(stderr, " (%s)\n", strerror(se));
716 	else
717 		fputc('\n', stderr);
718 	exit(e);
719 }
720 
721 protected void
722 file_errx(int e, const char *fmt, ...)
723 {
724 	va_list ap;
725 
726 	va_start(ap, fmt);
727 	fprintf(stderr, "%s: ", file_progname);
728 	vfprintf(stderr, fmt, ap);
729 	va_end(ap);
730 	fprintf(stderr, "\n");
731 	exit(e);
732 }
733 
734 protected void
735 file_warn(const char *fmt, ...)
736 {
737 	va_list ap;
738 	int se = errno;
739 
740 	va_start(ap, fmt);
741 	fprintf(stderr, "%s: ", file_progname);
742 	vfprintf(stderr, fmt, ap);
743 	va_end(ap);
744 	if (se)
745 		fprintf(stderr, " (%s)\n", strerror(se));
746 	else
747 		fputc('\n', stderr);
748 	errno = se;
749 }
750 
751 protected void
752 file_warnx(const char *fmt, ...)
753 {
754 	va_list ap;
755 	int se = errno;
756 
757 	va_start(ap, fmt);
758 	fprintf(stderr, "%s: ", file_progname);
759 	vfprintf(stderr, fmt, ap);
760 	va_end(ap);
761 	fprintf(stderr, "\n");
762 	errno = se;
763 }
764