xref: /freebsd/contrib/elftoolchain/addr2line/addr2line.c (revision 1f4bcc459a76b7aa664f3fd557684cd0ba6da352)
1 /*-
2  * Copyright (c) 2009 Kai Wang
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 AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include <sys/param.h>
28 #include <dwarf.h>
29 #include <err.h>
30 #include <fcntl.h>
31 #include <gelf.h>
32 #include <getopt.h>
33 #include <libdwarf.h>
34 #include <libelftc.h>
35 #include <libgen.h>
36 #include <stdio.h>
37 #include <stdlib.h>
38 #include <string.h>
39 
40 #include "uthash.h"
41 #include "_elftc.h"
42 
43 ELFTC_VCSID("$Id: addr2line.c 3264 2015-11-30 05:38:14Z kaiwang27 $");
44 
45 struct Func {
46 	char *name;
47 	Dwarf_Unsigned lopc;
48 	Dwarf_Unsigned hipc;
49 	Dwarf_Unsigned call_file;
50 	Dwarf_Unsigned call_line;
51 	Dwarf_Ranges *ranges;
52 	Dwarf_Signed ranges_cnt;
53 	struct Func *inlined_caller;
54 	STAILQ_ENTRY(Func) next;
55 };
56 
57 struct CU {
58 	Dwarf_Off off;
59 	Dwarf_Unsigned lopc;
60 	Dwarf_Unsigned hipc;
61 	char **srcfiles;
62 	Dwarf_Signed nsrcfiles;
63 	STAILQ_HEAD(, Func) funclist;
64 	UT_hash_handle hh;
65 };
66 
67 static struct option longopts[] = {
68 	{"addresses", no_argument, NULL, 'a'},
69 	{"target" , required_argument, NULL, 'b'},
70 	{"demangle", no_argument, NULL, 'C'},
71 	{"exe", required_argument, NULL, 'e'},
72 	{"functions", no_argument, NULL, 'f'},
73 	{"inlines", no_argument, NULL, 'i'},
74 	{"section", required_argument, NULL, 'j'},
75 	{"pretty-print", no_argument, NULL, 'p'},
76 	{"basename", no_argument, NULL, 's'},
77 	{"help", no_argument, NULL, 'H'},
78 	{"version", no_argument, NULL, 'V'},
79 	{NULL, 0, NULL, 0}
80 };
81 static int demangle, func, base, inlines, print_addr, pretty_print;
82 static char unknown[] = { '?', '?', '\0' };
83 static Dwarf_Addr section_base;
84 static struct CU *culist;
85 
86 #define	USAGE_MESSAGE	"\
87 Usage: %s [options] hexaddress...\n\
88   Map program addresses to source file names and line numbers.\n\n\
89   Options:\n\
90   -a      | --addresses       Display address prior to line number info.\n\
91   -b TGT  | --target=TGT      (Accepted but ignored).\n\
92   -e EXE  | --exe=EXE         Use program \"EXE\" to translate addresses.\n\
93   -f      | --functions       Display function names.\n\
94   -i      | --inlines         Display caller info for inlined functions.\n\
95   -j NAME | --section=NAME    Values are offsets into section \"NAME\".\n\
96   -p      | --pretty-print    Display line number info and function name\n\
97                               in human readable manner.\n\
98   -s      | --basename        Only show the base name for each file name.\n\
99   -C      | --demangle        Demangle C++ names.\n\
100   -H      | --help            Print a help message.\n\
101   -V      | --version         Print a version identifier and exit.\n"
102 
103 static void
104 usage(void)
105 {
106 	(void) fprintf(stderr, USAGE_MESSAGE, ELFTC_GETPROGNAME());
107 	exit(1);
108 }
109 
110 static void
111 version(void)
112 {
113 
114 	fprintf(stderr, "%s (%s)\n", ELFTC_GETPROGNAME(), elftc_version());
115 	exit(0);
116 }
117 
118 /*
119  * Handle DWARF 4 'offset from' DW_AT_high_pc.  Although we don't
120  * fully support DWARF 4, some compilers (like FreeBSD Clang 3.5.1)
121  * generate DW_AT_high_pc as an offset from DW_AT_low_pc.
122  *
123  * "If the value of the DW_AT_high_pc is of class address, it is the
124  * relocated address of the first location past the last instruction
125  * associated with the entity; if it is of class constant, the value
126  * is an unsigned integer offset which when added to the low PC gives
127  * the address of the first location past the last instruction
128  * associated with the entity."
129  *
130  * DWARF4 spec, section 2.17.2.
131  */
132 static int
133 handle_high_pc(Dwarf_Die die, Dwarf_Unsigned lopc, Dwarf_Unsigned *hipc)
134 {
135 	Dwarf_Error de;
136 	Dwarf_Half form;
137 	Dwarf_Attribute at;
138 	int ret;
139 
140 	ret = dwarf_attr(die, DW_AT_high_pc, &at, &de);
141 	if (ret == DW_DLV_ERROR) {
142 		warnx("dwarf_attr failed: %s", dwarf_errmsg(de));
143 		return (ret);
144 	}
145 	ret = dwarf_whatform(at, &form, &de);
146 	if (ret == DW_DLV_ERROR) {
147 		warnx("dwarf_whatform failed: %s", dwarf_errmsg(de));
148 		return (ret);
149 	}
150 	if (dwarf_get_form_class(2, 0, 0, form) == DW_FORM_CLASS_CONSTANT)
151 		*hipc += lopc;
152 
153 	return (DW_DLV_OK);
154 }
155 
156 static struct Func *
157 search_func(struct CU *cu, Dwarf_Unsigned addr)
158 {
159 	struct Func *f, *f0;
160 	Dwarf_Unsigned lopc, hipc, addr_base;
161 	int i;
162 
163 	f0 = NULL;
164 
165 	STAILQ_FOREACH(f, &cu->funclist, next) {
166 		if (f->ranges != NULL) {
167 			addr_base = 0;
168 			for (i = 0; i < f->ranges_cnt; i++) {
169 				if (f->ranges[i].dwr_type == DW_RANGES_END)
170 					break;
171 				if (f->ranges[i].dwr_type ==
172 				    DW_RANGES_ADDRESS_SELECTION) {
173 					addr_base = f->ranges[i].dwr_addr2;
174 					continue;
175 				}
176 
177 				/* DW_RANGES_ENTRY */
178 				lopc = f->ranges[i].dwr_addr1 + addr_base;
179 				hipc = f->ranges[i].dwr_addr2 + addr_base;
180 				if (addr >= lopc && addr < hipc) {
181 					if (f0 == NULL ||
182 					    (lopc >= f0->lopc &&
183 					    hipc <= f0->hipc)) {
184 						f0 = f;
185 						f0->lopc = lopc;
186 						f0->hipc = hipc;
187 						break;
188 					}
189 				}
190 			}
191 		} else if (addr >= f->lopc && addr < f->hipc) {
192 			if (f0 == NULL ||
193 			    (f->lopc >= f0->lopc && f->hipc <= f0->hipc))
194 				f0 = f;
195 		}
196 	}
197 
198 	return (f0);
199 }
200 
201 static void
202 collect_func(Dwarf_Debug dbg, Dwarf_Die die, struct Func *parent, struct CU *cu)
203 {
204 	Dwarf_Die ret_die, abst_die, spec_die;
205 	Dwarf_Error de;
206 	Dwarf_Half tag;
207 	Dwarf_Unsigned lopc, hipc, ranges_off;
208 	Dwarf_Signed ranges_cnt;
209 	Dwarf_Off ref;
210 	Dwarf_Attribute abst_at, spec_at;
211 	Dwarf_Ranges *ranges;
212 	const char *funcname;
213 	struct Func *f;
214 	int found_ranges, ret;
215 
216 	f = NULL;
217 	abst_die = spec_die = NULL;
218 
219 	if (dwarf_tag(die, &tag, &de)) {
220 		warnx("dwarf_tag: %s", dwarf_errmsg(de));
221 		goto cont_search;
222 	}
223 	if (tag == DW_TAG_subprogram || tag == DW_TAG_entry_point ||
224 	    tag == DW_TAG_inlined_subroutine) {
225 		/*
226 		 * Function address range can be specified by either
227 		 * a DW_AT_ranges attribute which points to a range list or
228 		 * by a pair of DW_AT_low_pc and DW_AT_high_pc attributes.
229 		 */
230 		ranges = NULL;
231 		ranges_cnt = 0;
232 		found_ranges = 0;
233 		if (dwarf_attrval_unsigned(die, DW_AT_ranges, &ranges_off,
234 		    &de) == DW_DLV_OK &&
235 		    dwarf_get_ranges(dbg, (Dwarf_Off) ranges_off, &ranges,
236 		    &ranges_cnt, NULL, &de) == DW_DLV_OK) {
237 			if (ranges != NULL && ranges_cnt > 0) {
238 				found_ranges = 1;
239 				goto get_func_name;
240 			}
241 		}
242 
243 		/*
244 		 * Search for DW_AT_low_pc/DW_AT_high_pc if ranges pointer
245 		 * not found.
246 		 */
247 		if (dwarf_attrval_unsigned(die, DW_AT_low_pc, &lopc, &de) ||
248 		    dwarf_attrval_unsigned(die, DW_AT_high_pc, &hipc, &de))
249 			goto cont_search;
250 		if (handle_high_pc(die, lopc, &hipc) != DW_DLV_OK)
251 			goto cont_search;
252 
253 	get_func_name:
254 		/*
255 		 * Most common case the function name is stored in DW_AT_name
256 		 * attribute.
257 		 */
258 		if (dwarf_attrval_string(die, DW_AT_name, &funcname, &de) ==
259 		    DW_DLV_OK)
260 			goto add_func;
261 
262 		/*
263 		 * For inlined function, the actual name is probably in the DIE
264 		 * referenced by DW_AT_abstract_origin. (if present)
265 		 */
266 		if (dwarf_attr(die, DW_AT_abstract_origin, &abst_at, &de) ==
267 		    DW_DLV_OK &&
268 		    dwarf_global_formref(abst_at, &ref, &de) == DW_DLV_OK &&
269 		    dwarf_offdie(dbg, ref, &abst_die, &de) == DW_DLV_OK &&
270 		    dwarf_attrval_string(abst_die, DW_AT_name, &funcname,
271 		    &de) == DW_DLV_OK)
272 			goto add_func;
273 
274 		/*
275 		 * If DW_AT_name is not present, but DW_AT_specification is
276 		 * present, then probably the actual name is in the DIE
277 		 * referenced by DW_AT_specification.
278 		 */
279 		if (dwarf_attr(die, DW_AT_specification, &spec_at, &de) ==
280 		    DW_DLV_OK &&
281 		    dwarf_global_formref(spec_at, &ref, &de) == DW_DLV_OK &&
282 		    dwarf_offdie(dbg, ref, &spec_die, &de) == DW_DLV_OK &&
283 		    dwarf_attrval_string(spec_die, DW_AT_name, &funcname,
284 		    &de) == DW_DLV_OK)
285 			goto add_func;
286 
287 		/* Skip if no name assoicated with this DIE. */
288 		goto cont_search;
289 
290 	add_func:
291 		if ((f = calloc(1, sizeof(*f))) == NULL)
292 			err(EXIT_FAILURE, "calloc");
293 		if ((f->name = strdup(funcname)) == NULL)
294 			err(EXIT_FAILURE, "strdup");
295 		if (found_ranges) {
296 			f->ranges = ranges;
297 			f->ranges_cnt = ranges_cnt;
298 		} else {
299 			f->lopc = lopc;
300 			f->hipc = hipc;
301 		}
302 		if (tag == DW_TAG_inlined_subroutine) {
303 			f->inlined_caller = parent;
304 			dwarf_attrval_unsigned(die, DW_AT_call_file,
305 			    &f->call_file, &de);
306 			dwarf_attrval_unsigned(die, DW_AT_call_line,
307 			    &f->call_line, &de);
308 		}
309 		STAILQ_INSERT_TAIL(&cu->funclist, f, next);
310 	}
311 
312 cont_search:
313 
314 	/* Search children. */
315 	ret = dwarf_child(die, &ret_die, &de);
316 	if (ret == DW_DLV_ERROR)
317 		warnx("dwarf_child: %s", dwarf_errmsg(de));
318 	else if (ret == DW_DLV_OK) {
319 		if (f != NULL)
320 			collect_func(dbg, ret_die, f, cu);
321 		else
322 			collect_func(dbg, ret_die, parent, cu);
323 	}
324 
325 	/* Search sibling. */
326 	ret = dwarf_siblingof(dbg, die, &ret_die, &de);
327 	if (ret == DW_DLV_ERROR)
328 		warnx("dwarf_siblingof: %s", dwarf_errmsg(de));
329 	else if (ret == DW_DLV_OK)
330 		collect_func(dbg, ret_die, parent, cu);
331 
332 	/* Cleanup */
333 	dwarf_dealloc(dbg, die, DW_DLA_DIE);
334 
335 	if (abst_die != NULL)
336 		dwarf_dealloc(dbg, abst_die, DW_DLA_DIE);
337 
338 	if (spec_die != NULL)
339 		dwarf_dealloc(dbg, spec_die, DW_DLA_DIE);
340 }
341 
342 static void
343 print_inlines(struct CU *cu, struct Func *f, Dwarf_Unsigned call_file,
344     Dwarf_Unsigned call_line)
345 {
346 	char demangled[1024];
347 	char *file;
348 
349 	if (call_file > 0 && (Dwarf_Signed) call_file <= cu->nsrcfiles)
350 		file = cu->srcfiles[call_file - 1];
351 	else
352 		file = unknown;
353 
354 	if (pretty_print)
355 		printf(" (inlined by) ");
356 
357 	if (func) {
358 		if (demangle && !elftc_demangle(f->name, demangled,
359 		    sizeof(demangled), 0)) {
360 			if (pretty_print)
361 				printf("%s at ", demangled);
362 			else
363 				printf("%s\n", demangled);
364 		} else {
365 			if (pretty_print)
366 				printf("%s at ", f->name);
367 			else
368 				printf("%s\n", f->name);
369 		}
370 	}
371 	(void) printf("%s:%ju\n", base ? basename(file) : file, call_line);
372 
373 	if (f->inlined_caller != NULL)
374 		print_inlines(cu, f->inlined_caller, f->call_file,
375 		    f->call_line);
376 }
377 
378 static void
379 translate(Dwarf_Debug dbg, Elf *e, const char* addrstr)
380 {
381 	Dwarf_Die die, ret_die;
382 	Dwarf_Line *lbuf;
383 	Dwarf_Error de;
384 	Dwarf_Half tag;
385 	Dwarf_Unsigned lopc, hipc, addr, lineno, plineno;
386 	Dwarf_Signed lcount;
387 	Dwarf_Addr lineaddr, plineaddr;
388 	Dwarf_Off off;
389 	struct CU *cu;
390 	struct Func *f;
391 	const char *funcname;
392 	char *file, *file0, *pfile;
393 	char demangled[1024];
394 	int ec, i, ret;
395 
396 	addr = strtoull(addrstr, NULL, 16);
397 	addr += section_base;
398 	lineno = 0;
399 	file = unknown;
400 	cu = NULL;
401 	die = NULL;
402 
403 	while ((ret = dwarf_next_cu_header(dbg, NULL, NULL, NULL, NULL, NULL,
404 	    &de)) ==  DW_DLV_OK) {
405 		die = NULL;
406 		while (dwarf_siblingof(dbg, die, &ret_die, &de) == DW_DLV_OK) {
407 			if (die != NULL)
408 				dwarf_dealloc(dbg, die, DW_DLA_DIE);
409 			die = ret_die;
410 			if (dwarf_tag(die, &tag, &de) != DW_DLV_OK) {
411 				warnx("dwarf_tag failed: %s",
412 				    dwarf_errmsg(de));
413 				goto next_cu;
414 			}
415 
416 			/* XXX: What about DW_TAG_partial_unit? */
417 			if (tag == DW_TAG_compile_unit)
418 				break;
419 		}
420 		if (ret_die == NULL) {
421 			warnx("could not find DW_TAG_compile_unit die");
422 			goto next_cu;
423 		}
424 		if (dwarf_attrval_unsigned(die, DW_AT_low_pc, &lopc, &de) ==
425 		    DW_DLV_OK) {
426 			if (dwarf_attrval_unsigned(die, DW_AT_high_pc, &hipc,
427 			   &de) == DW_DLV_OK) {
428 				/*
429 				 * Check if the address falls into the PC
430 				 * range of this CU.
431 				 */
432 				if (handle_high_pc(die, lopc, &hipc) !=
433 				    DW_DLV_OK)
434 					goto out;
435 			} else {
436 				/* Assume ~0ULL if DW_AT_high_pc not present */
437 				hipc = ~0ULL;
438 			}
439 
440 			/*
441 			 * Record the CU in the hash table for faster lookup
442 			 * later.
443 			 */
444 			if (dwarf_dieoffset(die, &off, &de) != DW_DLV_OK) {
445 				warnx("dwarf_dieoffset failed: %s",
446 				    dwarf_errmsg(de));
447 				goto out;
448 			}
449 			HASH_FIND(hh, culist, &off, sizeof(off), cu);
450 			if (cu == NULL) {
451 				if ((cu = calloc(1, sizeof(*cu))) == NULL)
452 					err(EXIT_FAILURE, "calloc");
453 				cu->off = off;
454 				cu->lopc = lopc;
455 				cu->hipc = hipc;
456 				STAILQ_INIT(&cu->funclist);
457 				HASH_ADD(hh, culist, off, sizeof(off), cu);
458 			}
459 
460 			if (addr >= lopc && addr < hipc)
461 				break;
462 		}
463 
464 	next_cu:
465 		if (die != NULL) {
466 			dwarf_dealloc(dbg, die, DW_DLA_DIE);
467 			die = NULL;
468 		}
469 	}
470 
471 	if (ret != DW_DLV_OK || die == NULL)
472 		goto out;
473 
474 	switch (dwarf_srclines(die, &lbuf, &lcount, &de)) {
475 	case DW_DLV_OK:
476 		break;
477 	case DW_DLV_NO_ENTRY:
478 		/* If a CU lacks debug info, just skip it. */
479 		goto out;
480 	default:
481 		warnx("dwarf_srclines: %s", dwarf_errmsg(de));
482 		goto out;
483 	}
484 
485 	plineaddr = ~0ULL;
486 	plineno = 0;
487 	pfile = unknown;
488 	for (i = 0; i < lcount; i++) {
489 		if (dwarf_lineaddr(lbuf[i], &lineaddr, &de)) {
490 			warnx("dwarf_lineaddr: %s", dwarf_errmsg(de));
491 			goto out;
492 		}
493 		if (dwarf_lineno(lbuf[i], &lineno, &de)) {
494 			warnx("dwarf_lineno: %s", dwarf_errmsg(de));
495 			goto out;
496 		}
497 		if (dwarf_linesrc(lbuf[i], &file0, &de)) {
498 			warnx("dwarf_linesrc: %s", dwarf_errmsg(de));
499 		} else
500 			file = file0;
501 		if (addr == lineaddr)
502 			goto out;
503 		else if (addr < lineaddr && addr > plineaddr) {
504 			lineno = plineno;
505 			file = pfile;
506 			goto out;
507 		}
508 		plineaddr = lineaddr;
509 		plineno = lineno;
510 		pfile = file;
511 	}
512 
513 out:
514 	f = NULL;
515 	funcname = NULL;
516 	if (ret == DW_DLV_OK && (func || inlines) && cu != NULL) {
517 		if (cu->srcfiles == NULL)
518 			if (dwarf_srcfiles(die, &cu->srcfiles, &cu->nsrcfiles,
519 			    &de))
520 				warnx("dwarf_srcfiles: %s", dwarf_errmsg(de));
521 		if (STAILQ_EMPTY(&cu->funclist)) {
522 			collect_func(dbg, die, NULL, cu);
523 			die = NULL;
524 		}
525 		f = search_func(cu, addr);
526 		if (f != NULL)
527 			funcname = f->name;
528 	}
529 
530 	if (print_addr) {
531 		if ((ec = gelf_getclass(e)) == ELFCLASSNONE) {
532 			warnx("gelf_getclass failed: %s", elf_errmsg(-1));
533 			ec = ELFCLASS64;
534 		}
535 		if (ec == ELFCLASS32) {
536 			if (pretty_print)
537 				printf("0x%08jx: ", (uintmax_t) addr);
538 			else
539 				printf("0x%08jx\n", (uintmax_t) addr);
540 		} else {
541 			if (pretty_print)
542 				printf("0x%016jx: ", (uintmax_t) addr);
543 			else
544 				printf("0x%016jx\n", (uintmax_t) addr);
545 		}
546 	}
547 
548 	if (func) {
549 		if (funcname == NULL)
550 			funcname = unknown;
551 		if (demangle && !elftc_demangle(funcname, demangled,
552 		    sizeof(demangled), 0)) {
553 			if (pretty_print)
554 				printf("%s at ", demangled);
555 			else
556 				printf("%s\n", demangled);
557 		} else {
558 			if (pretty_print)
559 				printf("%s at ", funcname);
560 			else
561 				printf("%s\n", funcname);
562 		}
563 	}
564 
565 	(void) printf("%s:%ju\n", base ? basename(file) : file, lineno);
566 
567 	if (ret == DW_DLV_OK && inlines && cu != NULL &&
568 	    cu->srcfiles != NULL && f != NULL && f->inlined_caller != NULL)
569 		print_inlines(cu, f->inlined_caller, f->call_file,
570 		    f->call_line);
571 
572 	if (die != NULL)
573 		dwarf_dealloc(dbg, die, DW_DLA_DIE);
574 
575 	/*
576 	 * Reset internal CU pointer, so we will start from the first CU
577 	 * next round.
578 	 */
579 	while (ret != DW_DLV_NO_ENTRY) {
580 		if (ret == DW_DLV_ERROR)
581 			errx(EXIT_FAILURE, "dwarf_next_cu_header: %s",
582 			    dwarf_errmsg(de));
583 		ret = dwarf_next_cu_header(dbg, NULL, NULL, NULL, NULL, NULL,
584 		    &de);
585 	}
586 }
587 
588 static void
589 find_section_base(const char *exe, Elf *e, const char *section)
590 {
591 	Dwarf_Addr off;
592 	Elf_Scn *scn;
593 	GElf_Ehdr eh;
594 	GElf_Shdr sh;
595 	size_t shstrndx;
596 	int elferr;
597 	const char *name;
598 
599 	if (gelf_getehdr(e, &eh) != &eh) {
600 		warnx("gelf_getehdr failed: %s", elf_errmsg(-1));
601 		return;
602 	}
603 
604 	if (!elf_getshstrndx(e, &shstrndx)) {
605 		warnx("elf_getshstrndx failed: %s", elf_errmsg(-1));
606 		return;
607 	}
608 
609 	(void) elf_errno();
610 	off = 0;
611 	scn = NULL;
612 	while ((scn = elf_nextscn(e, scn)) != NULL) {
613 		if (gelf_getshdr(scn, &sh) == NULL) {
614 			warnx("gelf_getshdr failed: %s", elf_errmsg(-1));
615 			continue;
616 		}
617 		if ((name = elf_strptr(e, shstrndx, sh.sh_name)) == NULL)
618 			goto next;
619 		if (!strcmp(section, name)) {
620 			if (eh.e_type == ET_EXEC || eh.e_type == ET_DYN) {
621 				/*
622 				 * For executables, section base is the virtual
623 				 * address of the specified section.
624 				 */
625 				section_base = sh.sh_addr;
626 			} else if (eh.e_type == ET_REL) {
627 				/*
628 				 * For relocatables, section base is the
629 				 * relative offset of the specified section
630 				 * to the start of the first section.
631 				 */
632 				section_base = off;
633 			} else
634 				warnx("unknown e_type %u", eh.e_type);
635 			return;
636 		}
637 	next:
638 		off += sh.sh_size;
639 	}
640 	elferr = elf_errno();
641 	if (elferr != 0)
642 		warnx("elf_nextscn failed: %s", elf_errmsg(elferr));
643 
644 	errx(EXIT_FAILURE, "%s: cannot find section %s", exe, section);
645 }
646 
647 int
648 main(int argc, char **argv)
649 {
650 	Elf *e;
651 	Dwarf_Debug dbg;
652 	Dwarf_Error de;
653 	const char *exe, *section;
654 	char line[1024];
655 	int fd, i, opt;
656 
657 	exe = NULL;
658 	section = NULL;
659 	while ((opt = getopt_long(argc, argv, "ab:Ce:fij:psHV", longopts,
660 	    NULL)) != -1) {
661 		switch (opt) {
662 		case 'a':
663 			print_addr = 1;
664 			break;
665 		case 'b':
666 			/* ignored */
667 			break;
668 		case 'C':
669 			demangle = 1;
670 			break;
671 		case 'e':
672 			exe = optarg;
673 			break;
674 		case 'f':
675 			func = 1;
676 			break;
677 		case 'i':
678 			inlines = 1;
679 			break;
680 		case 'j':
681 			section = optarg;
682 			break;
683 		case 'p':
684 			pretty_print = 1;
685 			break;
686 		case 's':
687 			base = 1;
688 			break;
689 		case 'H':
690 			usage();
691 		case 'V':
692 			version();
693 		default:
694 			usage();
695 		}
696 	}
697 
698 	argv += optind;
699 	argc -= optind;
700 
701 	if (exe == NULL)
702 		exe = "a.out";
703 
704 	if ((fd = open(exe, O_RDONLY)) < 0)
705 		err(EXIT_FAILURE, "%s", exe);
706 
707 	if (dwarf_init(fd, DW_DLC_READ, NULL, NULL, &dbg, &de))
708 		errx(EXIT_FAILURE, "dwarf_init: %s", dwarf_errmsg(de));
709 
710 	if (dwarf_get_elf(dbg, &e, &de) != DW_DLV_OK)
711 		errx(EXIT_FAILURE, "dwarf_get_elf: %s", dwarf_errmsg(de));
712 
713 	if (section)
714 		find_section_base(exe, e, section);
715 	else
716 		section_base = 0;
717 
718 	if (argc > 0)
719 		for (i = 0; i < argc; i++)
720 			translate(dbg, e, argv[i]);
721 	else
722 		while (fgets(line, sizeof(line), stdin) != NULL) {
723 			translate(dbg, e, line);
724 			fflush(stdout);
725 		}
726 
727 	dwarf_finish(dbg, &de);
728 
729 	(void) elf_end(e);
730 
731 	exit(0);
732 }
733