xref: /freebsd/contrib/elftoolchain/addr2line/addr2line.c (revision 15c433351f54e7cd5bec8d36c8e89e6a7fa55b26)
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 3273 2015-12-11 21:38:57Z 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,
372 	    (uintmax_t) call_line);
373 
374 	if (f->inlined_caller != NULL)
375 		print_inlines(cu, f->inlined_caller, f->call_file,
376 		    f->call_line);
377 }
378 
379 static void
380 translate(Dwarf_Debug dbg, Elf *e, const char* addrstr)
381 {
382 	Dwarf_Die die, ret_die;
383 	Dwarf_Line *lbuf;
384 	Dwarf_Error de;
385 	Dwarf_Half tag;
386 	Dwarf_Unsigned lopc, hipc, addr, lineno, plineno;
387 	Dwarf_Signed lcount;
388 	Dwarf_Addr lineaddr, plineaddr;
389 	Dwarf_Off off;
390 	struct CU *cu;
391 	struct Func *f;
392 	const char *funcname;
393 	char *file, *file0, *pfile;
394 	char demangled[1024];
395 	int ec, i, ret;
396 
397 	addr = strtoull(addrstr, NULL, 16);
398 	addr += section_base;
399 	lineno = 0;
400 	file = unknown;
401 	cu = NULL;
402 	die = NULL;
403 
404 	while ((ret = dwarf_next_cu_header(dbg, NULL, NULL, NULL, NULL, NULL,
405 	    &de)) ==  DW_DLV_OK) {
406 		die = NULL;
407 		while (dwarf_siblingof(dbg, die, &ret_die, &de) == DW_DLV_OK) {
408 			if (die != NULL)
409 				dwarf_dealloc(dbg, die, DW_DLA_DIE);
410 			die = ret_die;
411 			if (dwarf_tag(die, &tag, &de) != DW_DLV_OK) {
412 				warnx("dwarf_tag failed: %s",
413 				    dwarf_errmsg(de));
414 				goto next_cu;
415 			}
416 
417 			/* XXX: What about DW_TAG_partial_unit? */
418 			if (tag == DW_TAG_compile_unit)
419 				break;
420 		}
421 		if (ret_die == NULL) {
422 			warnx("could not find DW_TAG_compile_unit die");
423 			goto next_cu;
424 		}
425 		if (dwarf_attrval_unsigned(die, DW_AT_low_pc, &lopc, &de) ==
426 		    DW_DLV_OK) {
427 			if (dwarf_attrval_unsigned(die, DW_AT_high_pc, &hipc,
428 			   &de) == DW_DLV_OK) {
429 				/*
430 				 * Check if the address falls into the PC
431 				 * range of this CU.
432 				 */
433 				if (handle_high_pc(die, lopc, &hipc) !=
434 				    DW_DLV_OK)
435 					goto out;
436 			} else {
437 				/* Assume ~0ULL if DW_AT_high_pc not present */
438 				hipc = ~0ULL;
439 			}
440 
441 			/*
442 			 * Record the CU in the hash table for faster lookup
443 			 * later.
444 			 */
445 			if (dwarf_dieoffset(die, &off, &de) != DW_DLV_OK) {
446 				warnx("dwarf_dieoffset failed: %s",
447 				    dwarf_errmsg(de));
448 				goto out;
449 			}
450 			HASH_FIND(hh, culist, &off, sizeof(off), cu);
451 			if (cu == NULL) {
452 				if ((cu = calloc(1, sizeof(*cu))) == NULL)
453 					err(EXIT_FAILURE, "calloc");
454 				cu->off = off;
455 				cu->lopc = lopc;
456 				cu->hipc = hipc;
457 				STAILQ_INIT(&cu->funclist);
458 				HASH_ADD(hh, culist, off, sizeof(off), cu);
459 			}
460 
461 			if (addr >= lopc && addr < hipc)
462 				break;
463 		}
464 
465 	next_cu:
466 		if (die != NULL) {
467 			dwarf_dealloc(dbg, die, DW_DLA_DIE);
468 			die = NULL;
469 		}
470 	}
471 
472 	if (ret != DW_DLV_OK || die == NULL)
473 		goto out;
474 
475 	switch (dwarf_srclines(die, &lbuf, &lcount, &de)) {
476 	case DW_DLV_OK:
477 		break;
478 	case DW_DLV_NO_ENTRY:
479 		/* If a CU lacks debug info, just skip it. */
480 		goto out;
481 	default:
482 		warnx("dwarf_srclines: %s", dwarf_errmsg(de));
483 		goto out;
484 	}
485 
486 	plineaddr = ~0ULL;
487 	plineno = 0;
488 	pfile = unknown;
489 	for (i = 0; i < lcount; i++) {
490 		if (dwarf_lineaddr(lbuf[i], &lineaddr, &de)) {
491 			warnx("dwarf_lineaddr: %s", dwarf_errmsg(de));
492 			goto out;
493 		}
494 		if (dwarf_lineno(lbuf[i], &lineno, &de)) {
495 			warnx("dwarf_lineno: %s", dwarf_errmsg(de));
496 			goto out;
497 		}
498 		if (dwarf_linesrc(lbuf[i], &file0, &de)) {
499 			warnx("dwarf_linesrc: %s", dwarf_errmsg(de));
500 		} else
501 			file = file0;
502 		if (addr == lineaddr)
503 			goto out;
504 		else if (addr < lineaddr && addr > plineaddr) {
505 			lineno = plineno;
506 			file = pfile;
507 			goto out;
508 		}
509 		plineaddr = lineaddr;
510 		plineno = lineno;
511 		pfile = file;
512 	}
513 
514 out:
515 	f = NULL;
516 	funcname = NULL;
517 	if (ret == DW_DLV_OK && (func || inlines) && cu != NULL) {
518 		if (cu->srcfiles == NULL)
519 			if (dwarf_srcfiles(die, &cu->srcfiles, &cu->nsrcfiles,
520 			    &de))
521 				warnx("dwarf_srcfiles: %s", dwarf_errmsg(de));
522 		if (STAILQ_EMPTY(&cu->funclist)) {
523 			collect_func(dbg, die, NULL, cu);
524 			die = NULL;
525 		}
526 		f = search_func(cu, addr);
527 		if (f != NULL)
528 			funcname = f->name;
529 	}
530 
531 	if (print_addr) {
532 		if ((ec = gelf_getclass(e)) == ELFCLASSNONE) {
533 			warnx("gelf_getclass failed: %s", elf_errmsg(-1));
534 			ec = ELFCLASS64;
535 		}
536 		if (ec == ELFCLASS32) {
537 			if (pretty_print)
538 				printf("0x%08jx: ", (uintmax_t) addr);
539 			else
540 				printf("0x%08jx\n", (uintmax_t) addr);
541 		} else {
542 			if (pretty_print)
543 				printf("0x%016jx: ", (uintmax_t) addr);
544 			else
545 				printf("0x%016jx\n", (uintmax_t) addr);
546 		}
547 	}
548 
549 	if (func) {
550 		if (funcname == NULL)
551 			funcname = unknown;
552 		if (demangle && !elftc_demangle(funcname, demangled,
553 		    sizeof(demangled), 0)) {
554 			if (pretty_print)
555 				printf("%s at ", demangled);
556 			else
557 				printf("%s\n", demangled);
558 		} else {
559 			if (pretty_print)
560 				printf("%s at ", funcname);
561 			else
562 				printf("%s\n", funcname);
563 		}
564 	}
565 
566 	(void) printf("%s:%ju\n", base ? basename(file) : file,
567 	    (uintmax_t) lineno);
568 
569 	if (ret == DW_DLV_OK && inlines && cu != NULL &&
570 	    cu->srcfiles != NULL && f != NULL && f->inlined_caller != NULL)
571 		print_inlines(cu, f->inlined_caller, f->call_file,
572 		    f->call_line);
573 
574 	if (die != NULL)
575 		dwarf_dealloc(dbg, die, DW_DLA_DIE);
576 
577 	/*
578 	 * Reset internal CU pointer, so we will start from the first CU
579 	 * next round.
580 	 */
581 	while (ret != DW_DLV_NO_ENTRY) {
582 		if (ret == DW_DLV_ERROR)
583 			errx(EXIT_FAILURE, "dwarf_next_cu_header: %s",
584 			    dwarf_errmsg(de));
585 		ret = dwarf_next_cu_header(dbg, NULL, NULL, NULL, NULL, NULL,
586 		    &de);
587 	}
588 }
589 
590 static void
591 find_section_base(const char *exe, Elf *e, const char *section)
592 {
593 	Dwarf_Addr off;
594 	Elf_Scn *scn;
595 	GElf_Ehdr eh;
596 	GElf_Shdr sh;
597 	size_t shstrndx;
598 	int elferr;
599 	const char *name;
600 
601 	if (gelf_getehdr(e, &eh) != &eh) {
602 		warnx("gelf_getehdr failed: %s", elf_errmsg(-1));
603 		return;
604 	}
605 
606 	if (!elf_getshstrndx(e, &shstrndx)) {
607 		warnx("elf_getshstrndx failed: %s", elf_errmsg(-1));
608 		return;
609 	}
610 
611 	(void) elf_errno();
612 	off = 0;
613 	scn = NULL;
614 	while ((scn = elf_nextscn(e, scn)) != NULL) {
615 		if (gelf_getshdr(scn, &sh) == NULL) {
616 			warnx("gelf_getshdr failed: %s", elf_errmsg(-1));
617 			continue;
618 		}
619 		if ((name = elf_strptr(e, shstrndx, sh.sh_name)) == NULL)
620 			goto next;
621 		if (!strcmp(section, name)) {
622 			if (eh.e_type == ET_EXEC || eh.e_type == ET_DYN) {
623 				/*
624 				 * For executables, section base is the virtual
625 				 * address of the specified section.
626 				 */
627 				section_base = sh.sh_addr;
628 			} else if (eh.e_type == ET_REL) {
629 				/*
630 				 * For relocatables, section base is the
631 				 * relative offset of the specified section
632 				 * to the start of the first section.
633 				 */
634 				section_base = off;
635 			} else
636 				warnx("unknown e_type %u", eh.e_type);
637 			return;
638 		}
639 	next:
640 		off += sh.sh_size;
641 	}
642 	elferr = elf_errno();
643 	if (elferr != 0)
644 		warnx("elf_nextscn failed: %s", elf_errmsg(elferr));
645 
646 	errx(EXIT_FAILURE, "%s: cannot find section %s", exe, section);
647 }
648 
649 int
650 main(int argc, char **argv)
651 {
652 	Elf *e;
653 	Dwarf_Debug dbg;
654 	Dwarf_Error de;
655 	const char *exe, *section;
656 	char line[1024];
657 	int fd, i, opt;
658 
659 	exe = NULL;
660 	section = NULL;
661 	while ((opt = getopt_long(argc, argv, "ab:Ce:fij:psHV", longopts,
662 	    NULL)) != -1) {
663 		switch (opt) {
664 		case 'a':
665 			print_addr = 1;
666 			break;
667 		case 'b':
668 			/* ignored */
669 			break;
670 		case 'C':
671 			demangle = 1;
672 			break;
673 		case 'e':
674 			exe = optarg;
675 			break;
676 		case 'f':
677 			func = 1;
678 			break;
679 		case 'i':
680 			inlines = 1;
681 			break;
682 		case 'j':
683 			section = optarg;
684 			break;
685 		case 'p':
686 			pretty_print = 1;
687 			break;
688 		case 's':
689 			base = 1;
690 			break;
691 		case 'H':
692 			usage();
693 		case 'V':
694 			version();
695 		default:
696 			usage();
697 		}
698 	}
699 
700 	argv += optind;
701 	argc -= optind;
702 
703 	if (exe == NULL)
704 		exe = "a.out";
705 
706 	if ((fd = open(exe, O_RDONLY)) < 0)
707 		err(EXIT_FAILURE, "%s", exe);
708 
709 	if (dwarf_init(fd, DW_DLC_READ, NULL, NULL, &dbg, &de))
710 		errx(EXIT_FAILURE, "dwarf_init: %s", dwarf_errmsg(de));
711 
712 	if (dwarf_get_elf(dbg, &e, &de) != DW_DLV_OK)
713 		errx(EXIT_FAILURE, "dwarf_get_elf: %s", dwarf_errmsg(de));
714 
715 	if (section)
716 		find_section_base(exe, e, section);
717 	else
718 		section_base = 0;
719 
720 	if (argc > 0)
721 		for (i = 0; i < argc; i++)
722 			translate(dbg, e, argv[i]);
723 	else
724 		while (fgets(line, sizeof(line), stdin) != NULL) {
725 			translate(dbg, e, line);
726 			fflush(stdout);
727 		}
728 
729 	dwarf_finish(dbg, &de);
730 
731 	(void) elf_end(e);
732 
733 	exit(0);
734 }
735