1 /*
2  * probe-finder.c : C expression to kprobe event converter
3  *
4  * Written by Masami Hiramatsu <mhiramat@redhat.com>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19  *
20  */
21 
22 #include <sys/utsname.h>
23 #include <sys/types.h>
24 #include <sys/stat.h>
25 #include <fcntl.h>
26 #include <errno.h>
27 #include <stdio.h>
28 #include <unistd.h>
29 #include <getopt.h>
30 #include <stdlib.h>
31 #include <string.h>
32 #include <stdarg.h>
33 #include <ctype.h>
34 #include <dwarf-regs.h>
35 
36 #include <linux/bitops.h>
37 #include "event.h"
38 #include "debug.h"
39 #include "util.h"
40 #include "symbol.h"
41 #include "probe-finder.h"
42 
43 /* Kprobe tracer basic type is up to u64 */
44 #define MAX_BASIC_TYPE_BITS	64
45 
46 /*
47  * Compare the tail of two strings.
48  * Return 0 if whole of either string is same as another's tail part.
49  */
strtailcmp(const char * s1,const char * s2)50 static int strtailcmp(const char *s1, const char *s2)
51 {
52 	int i1 = strlen(s1);
53 	int i2 = strlen(s2);
54 	while (--i1 >= 0 && --i2 >= 0) {
55 		if (s1[i1] != s2[i2])
56 			return s1[i1] - s2[i2];
57 	}
58 	return 0;
59 }
60 
61 /* Line number list operations */
62 
63 /* Add a line to line number list */
line_list__add_line(struct list_head * head,int line)64 static int line_list__add_line(struct list_head *head, int line)
65 {
66 	struct line_node *ln;
67 	struct list_head *p;
68 
69 	/* Reverse search, because new line will be the last one */
70 	list_for_each_entry_reverse(ln, head, list) {
71 		if (ln->line < line) {
72 			p = &ln->list;
73 			goto found;
74 		} else if (ln->line == line)	/* Already exist */
75 			return 1;
76 	}
77 	/* List is empty, or the smallest entry */
78 	p = head;
79 found:
80 	pr_debug("line list: add a line %u\n", line);
81 	ln = zalloc(sizeof(struct line_node));
82 	if (ln == NULL)
83 		return -ENOMEM;
84 	ln->line = line;
85 	INIT_LIST_HEAD(&ln->list);
86 	list_add(&ln->list, p);
87 	return 0;
88 }
89 
90 /* Check if the line in line number list */
line_list__has_line(struct list_head * head,int line)91 static int line_list__has_line(struct list_head *head, int line)
92 {
93 	struct line_node *ln;
94 
95 	/* Reverse search, because new line will be the last one */
96 	list_for_each_entry(ln, head, list)
97 		if (ln->line == line)
98 			return 1;
99 
100 	return 0;
101 }
102 
103 /* Init line number list */
line_list__init(struct list_head * head)104 static void line_list__init(struct list_head *head)
105 {
106 	INIT_LIST_HEAD(head);
107 }
108 
109 /* Free line number list */
line_list__free(struct list_head * head)110 static void line_list__free(struct list_head *head)
111 {
112 	struct line_node *ln;
113 	while (!list_empty(head)) {
114 		ln = list_first_entry(head, struct line_node, list);
115 		list_del(&ln->list);
116 		free(ln);
117 	}
118 }
119 
120 /* Dwarf FL wrappers */
121 static char *debuginfo_path;	/* Currently dummy */
122 
123 static const Dwfl_Callbacks offline_callbacks = {
124 	.find_debuginfo = dwfl_standard_find_debuginfo,
125 	.debuginfo_path = &debuginfo_path,
126 
127 	.section_address = dwfl_offline_section_address,
128 
129 	/* We use this table for core files too.  */
130 	.find_elf = dwfl_build_id_find_elf,
131 };
132 
133 /* Get a Dwarf from offline image */
dwfl_init_offline_dwarf(int fd,Dwfl ** dwflp,Dwarf_Addr * bias)134 static Dwarf *dwfl_init_offline_dwarf(int fd, Dwfl **dwflp, Dwarf_Addr *bias)
135 {
136 	Dwfl_Module *mod;
137 	Dwarf *dbg = NULL;
138 
139 	if (!dwflp)
140 		return NULL;
141 
142 	*dwflp = dwfl_begin(&offline_callbacks);
143 	if (!*dwflp)
144 		return NULL;
145 
146 	mod = dwfl_report_offline(*dwflp, "", "", fd);
147 	if (!mod)
148 		goto error;
149 
150 	dbg = dwfl_module_getdwarf(mod, bias);
151 	if (!dbg) {
152 error:
153 		dwfl_end(*dwflp);
154 		*dwflp = NULL;
155 	}
156 	return dbg;
157 }
158 
159 #if _ELFUTILS_PREREQ(0, 148)
160 /* This method is buggy if elfutils is older than 0.148 */
__linux_kernel_find_elf(Dwfl_Module * mod,void ** userdata,const char * module_name,Dwarf_Addr base,char ** file_name,Elf ** elfp)161 static int __linux_kernel_find_elf(Dwfl_Module *mod,
162 				   void **userdata,
163 				   const char *module_name,
164 				   Dwarf_Addr base,
165 				   char **file_name, Elf **elfp)
166 {
167 	int fd;
168 	const char *path = kernel_get_module_path(module_name);
169 
170 	pr_debug2("Use file %s for %s\n", path, module_name);
171 	if (path) {
172 		fd = open(path, O_RDONLY);
173 		if (fd >= 0) {
174 			*file_name = strdup(path);
175 			return fd;
176 		}
177 	}
178 	/* If failed, try to call standard method */
179 	return dwfl_linux_kernel_find_elf(mod, userdata, module_name, base,
180 					  file_name, elfp);
181 }
182 
183 static const Dwfl_Callbacks kernel_callbacks = {
184 	.find_debuginfo = dwfl_standard_find_debuginfo,
185 	.debuginfo_path = &debuginfo_path,
186 
187 	.find_elf = __linux_kernel_find_elf,
188 	.section_address = dwfl_linux_kernel_module_section_address,
189 };
190 
191 /* Get a Dwarf from live kernel image */
dwfl_init_live_kernel_dwarf(Dwarf_Addr addr,Dwfl ** dwflp,Dwarf_Addr * bias)192 static Dwarf *dwfl_init_live_kernel_dwarf(Dwarf_Addr addr, Dwfl **dwflp,
193 					  Dwarf_Addr *bias)
194 {
195 	Dwarf *dbg;
196 
197 	if (!dwflp)
198 		return NULL;
199 
200 	*dwflp = dwfl_begin(&kernel_callbacks);
201 	if (!*dwflp)
202 		return NULL;
203 
204 	/* Load the kernel dwarves: Don't care the result here */
205 	dwfl_linux_kernel_report_kernel(*dwflp);
206 	dwfl_linux_kernel_report_modules(*dwflp);
207 
208 	dbg = dwfl_addrdwarf(*dwflp, addr, bias);
209 	/* Here, check whether we could get a real dwarf */
210 	if (!dbg) {
211 		pr_debug("Failed to find kernel dwarf at %lx\n",
212 			 (unsigned long)addr);
213 		dwfl_end(*dwflp);
214 		*dwflp = NULL;
215 	}
216 	return dbg;
217 }
218 #else
219 /* With older elfutils, this just support kernel module... */
dwfl_init_live_kernel_dwarf(Dwarf_Addr addr __used,Dwfl ** dwflp,Dwarf_Addr * bias)220 static Dwarf *dwfl_init_live_kernel_dwarf(Dwarf_Addr addr __used, Dwfl **dwflp,
221 					  Dwarf_Addr *bias)
222 {
223 	int fd;
224 	const char *path = kernel_get_module_path("kernel");
225 
226 	if (!path) {
227 		pr_err("Failed to find vmlinux path\n");
228 		return NULL;
229 	}
230 
231 	pr_debug2("Use file %s for debuginfo\n", path);
232 	fd = open(path, O_RDONLY);
233 	if (fd < 0)
234 		return NULL;
235 
236 	return dwfl_init_offline_dwarf(fd, dwflp, bias);
237 }
238 #endif
239 
240 /* Dwarf wrappers */
241 
242 /* Find the realpath of the target file. */
cu_find_realpath(Dwarf_Die * cu_die,const char * fname)243 static const char *cu_find_realpath(Dwarf_Die *cu_die, const char *fname)
244 {
245 	Dwarf_Files *files;
246 	size_t nfiles, i;
247 	const char *src = NULL;
248 	int ret;
249 
250 	if (!fname)
251 		return NULL;
252 
253 	ret = dwarf_getsrcfiles(cu_die, &files, &nfiles);
254 	if (ret != 0)
255 		return NULL;
256 
257 	for (i = 0; i < nfiles; i++) {
258 		src = dwarf_filesrc(files, i, NULL, NULL);
259 		if (strtailcmp(src, fname) == 0)
260 			break;
261 	}
262 	if (i == nfiles)
263 		return NULL;
264 	return src;
265 }
266 
267 /* Get DW_AT_comp_dir (should be NULL with older gcc) */
cu_get_comp_dir(Dwarf_Die * cu_die)268 static const char *cu_get_comp_dir(Dwarf_Die *cu_die)
269 {
270 	Dwarf_Attribute attr;
271 	if (dwarf_attr(cu_die, DW_AT_comp_dir, &attr) == NULL)
272 		return NULL;
273 	return dwarf_formstring(&attr);
274 }
275 
276 /* Get a line number and file name for given address */
cu_find_lineinfo(Dwarf_Die * cudie,unsigned long addr,const char ** fname,int * lineno)277 static int cu_find_lineinfo(Dwarf_Die *cudie, unsigned long addr,
278 			    const char **fname, int *lineno)
279 {
280 	Dwarf_Line *line;
281 	Dwarf_Addr laddr;
282 
283 	line = dwarf_getsrc_die(cudie, (Dwarf_Addr)addr);
284 	if (line && dwarf_lineaddr(line, &laddr) == 0 &&
285 	    addr == (unsigned long)laddr && dwarf_lineno(line, lineno) == 0) {
286 		*fname = dwarf_linesrc(line, NULL, NULL);
287 		if (!*fname)
288 			/* line number is useless without filename */
289 			*lineno = 0;
290 	}
291 
292 	return *lineno ?: -ENOENT;
293 }
294 
295 /* Compare diename and tname */
die_compare_name(Dwarf_Die * dw_die,const char * tname)296 static bool die_compare_name(Dwarf_Die *dw_die, const char *tname)
297 {
298 	const char *name;
299 	name = dwarf_diename(dw_die);
300 	return name ? (strcmp(tname, name) == 0) : false;
301 }
302 
303 /* Get callsite line number of inline-function instance */
die_get_call_lineno(Dwarf_Die * in_die)304 static int die_get_call_lineno(Dwarf_Die *in_die)
305 {
306 	Dwarf_Attribute attr;
307 	Dwarf_Word ret;
308 
309 	if (!dwarf_attr(in_die, DW_AT_call_line, &attr))
310 		return -ENOENT;
311 
312 	dwarf_formudata(&attr, &ret);
313 	return (int)ret;
314 }
315 
316 /* Get type die */
die_get_type(Dwarf_Die * vr_die,Dwarf_Die * die_mem)317 static Dwarf_Die *die_get_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
318 {
319 	Dwarf_Attribute attr;
320 
321 	if (dwarf_attr_integrate(vr_die, DW_AT_type, &attr) &&
322 	    dwarf_formref_die(&attr, die_mem))
323 		return die_mem;
324 	else
325 		return NULL;
326 }
327 
328 /* Get a type die, but skip qualifiers */
__die_get_real_type(Dwarf_Die * vr_die,Dwarf_Die * die_mem)329 static Dwarf_Die *__die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
330 {
331 	int tag;
332 
333 	do {
334 		vr_die = die_get_type(vr_die, die_mem);
335 		if (!vr_die)
336 			break;
337 		tag = dwarf_tag(vr_die);
338 	} while (tag == DW_TAG_const_type ||
339 		 tag == DW_TAG_restrict_type ||
340 		 tag == DW_TAG_volatile_type ||
341 		 tag == DW_TAG_shared_type);
342 
343 	return vr_die;
344 }
345 
346 /* Get a type die, but skip qualifiers and typedef */
die_get_real_type(Dwarf_Die * vr_die,Dwarf_Die * die_mem)347 static Dwarf_Die *die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
348 {
349 	do {
350 		vr_die = __die_get_real_type(vr_die, die_mem);
351 	} while (vr_die && dwarf_tag(vr_die) == DW_TAG_typedef);
352 
353 	return vr_die;
354 }
355 
die_get_attr_udata(Dwarf_Die * tp_die,unsigned int attr_name,Dwarf_Word * result)356 static int die_get_attr_udata(Dwarf_Die *tp_die, unsigned int attr_name,
357 			      Dwarf_Word *result)
358 {
359 	Dwarf_Attribute attr;
360 
361 	if (dwarf_attr(tp_die, attr_name, &attr) == NULL ||
362 	    dwarf_formudata(&attr, result) != 0)
363 		return -ENOENT;
364 
365 	return 0;
366 }
367 
die_is_signed_type(Dwarf_Die * tp_die)368 static bool die_is_signed_type(Dwarf_Die *tp_die)
369 {
370 	Dwarf_Word ret;
371 
372 	if (die_get_attr_udata(tp_die, DW_AT_encoding, &ret))
373 		return false;
374 
375 	return (ret == DW_ATE_signed_char || ret == DW_ATE_signed ||
376 		ret == DW_ATE_signed_fixed);
377 }
378 
die_get_byte_size(Dwarf_Die * tp_die)379 static int die_get_byte_size(Dwarf_Die *tp_die)
380 {
381 	Dwarf_Word ret;
382 
383 	if (die_get_attr_udata(tp_die, DW_AT_byte_size, &ret))
384 		return 0;
385 
386 	return (int)ret;
387 }
388 
die_get_bit_size(Dwarf_Die * tp_die)389 static int die_get_bit_size(Dwarf_Die *tp_die)
390 {
391 	Dwarf_Word ret;
392 
393 	if (die_get_attr_udata(tp_die, DW_AT_bit_size, &ret))
394 		return 0;
395 
396 	return (int)ret;
397 }
398 
die_get_bit_offset(Dwarf_Die * tp_die)399 static int die_get_bit_offset(Dwarf_Die *tp_die)
400 {
401 	Dwarf_Word ret;
402 
403 	if (die_get_attr_udata(tp_die, DW_AT_bit_offset, &ret))
404 		return 0;
405 
406 	return (int)ret;
407 }
408 
409 /* Get data_member_location offset */
die_get_data_member_location(Dwarf_Die * mb_die,Dwarf_Word * offs)410 static int die_get_data_member_location(Dwarf_Die *mb_die, Dwarf_Word *offs)
411 {
412 	Dwarf_Attribute attr;
413 	Dwarf_Op *expr;
414 	size_t nexpr;
415 	int ret;
416 
417 	if (dwarf_attr(mb_die, DW_AT_data_member_location, &attr) == NULL)
418 		return -ENOENT;
419 
420 	if (dwarf_formudata(&attr, offs) != 0) {
421 		/* DW_AT_data_member_location should be DW_OP_plus_uconst */
422 		ret = dwarf_getlocation(&attr, &expr, &nexpr);
423 		if (ret < 0 || nexpr == 0)
424 			return -ENOENT;
425 
426 		if (expr[0].atom != DW_OP_plus_uconst || nexpr != 1) {
427 			pr_debug("Unable to get offset:Unexpected OP %x (%zd)\n",
428 				 expr[0].atom, nexpr);
429 			return -ENOTSUP;
430 		}
431 		*offs = (Dwarf_Word)expr[0].number;
432 	}
433 	return 0;
434 }
435 
436 /* Return values for die_find callbacks */
437 enum {
438 	DIE_FIND_CB_FOUND = 0,		/* End of Search */
439 	DIE_FIND_CB_CHILD = 1,		/* Search only children */
440 	DIE_FIND_CB_SIBLING = 2,	/* Search only siblings */
441 	DIE_FIND_CB_CONTINUE = 3,	/* Search children and siblings */
442 };
443 
444 /* Search a child die */
die_find_child(Dwarf_Die * rt_die,int (* callback)(Dwarf_Die *,void *),void * data,Dwarf_Die * die_mem)445 static Dwarf_Die *die_find_child(Dwarf_Die *rt_die,
446 				 int (*callback)(Dwarf_Die *, void *),
447 				 void *data, Dwarf_Die *die_mem)
448 {
449 	Dwarf_Die child_die;
450 	int ret;
451 
452 	ret = dwarf_child(rt_die, die_mem);
453 	if (ret != 0)
454 		return NULL;
455 
456 	do {
457 		ret = callback(die_mem, data);
458 		if (ret == DIE_FIND_CB_FOUND)
459 			return die_mem;
460 
461 		if ((ret & DIE_FIND_CB_CHILD) &&
462 		    die_find_child(die_mem, callback, data, &child_die)) {
463 			memcpy(die_mem, &child_die, sizeof(Dwarf_Die));
464 			return die_mem;
465 		}
466 	} while ((ret & DIE_FIND_CB_SIBLING) &&
467 		 dwarf_siblingof(die_mem, die_mem) == 0);
468 
469 	return NULL;
470 }
471 
472 struct __addr_die_search_param {
473 	Dwarf_Addr	addr;
474 	Dwarf_Die	*die_mem;
475 };
476 
__die_search_func_cb(Dwarf_Die * fn_die,void * data)477 static int __die_search_func_cb(Dwarf_Die *fn_die, void *data)
478 {
479 	struct __addr_die_search_param *ad = data;
480 
481 	if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
482 	    dwarf_haspc(fn_die, ad->addr)) {
483 		memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
484 		return DWARF_CB_ABORT;
485 	}
486 	return DWARF_CB_OK;
487 }
488 
489 /* Search a real subprogram including this line, */
die_find_real_subprogram(Dwarf_Die * cu_die,Dwarf_Addr addr,Dwarf_Die * die_mem)490 static Dwarf_Die *die_find_real_subprogram(Dwarf_Die *cu_die, Dwarf_Addr addr,
491 					   Dwarf_Die *die_mem)
492 {
493 	struct __addr_die_search_param ad;
494 	ad.addr = addr;
495 	ad.die_mem = die_mem;
496 	/* dwarf_getscopes can't find subprogram. */
497 	if (!dwarf_getfuncs(cu_die, __die_search_func_cb, &ad, 0))
498 		return NULL;
499 	else
500 		return die_mem;
501 }
502 
503 /* die_find callback for inline function search */
__die_find_inline_cb(Dwarf_Die * die_mem,void * data)504 static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data)
505 {
506 	Dwarf_Addr *addr = data;
507 
508 	if (dwarf_tag(die_mem) == DW_TAG_inlined_subroutine &&
509 	    dwarf_haspc(die_mem, *addr))
510 		return DIE_FIND_CB_FOUND;
511 
512 	return DIE_FIND_CB_CONTINUE;
513 }
514 
515 /* Similar to dwarf_getfuncs, but returns inlined_subroutine if exists. */
die_find_inlinefunc(Dwarf_Die * sp_die,Dwarf_Addr addr,Dwarf_Die * die_mem)516 static Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
517 				      Dwarf_Die *die_mem)
518 {
519 	Dwarf_Die tmp_die;
520 
521 	sp_die = die_find_child(sp_die, __die_find_inline_cb, &addr, &tmp_die);
522 	if (!sp_die)
523 		return NULL;
524 
525 	/* Inlined function could be recursive. Trace it until fail */
526 	while (sp_die) {
527 		memcpy(die_mem, sp_die, sizeof(Dwarf_Die));
528 		sp_die = die_find_child(sp_die, __die_find_inline_cb, &addr,
529 					&tmp_die);
530 	}
531 
532 	return die_mem;
533 }
534 
535 /* Walker on lines (Note: line number will not be sorted) */
536 typedef int (* line_walk_handler_t) (const char *fname, int lineno,
537 				     Dwarf_Addr addr, void *data);
538 
539 struct __line_walk_param {
540 	const char *fname;
541 	line_walk_handler_t handler;
542 	void *data;
543 	int retval;
544 };
545 
__die_walk_funclines_cb(Dwarf_Die * in_die,void * data)546 static int __die_walk_funclines_cb(Dwarf_Die *in_die, void *data)
547 {
548 	struct __line_walk_param *lw = data;
549 	Dwarf_Addr addr;
550 	int lineno;
551 
552 	if (dwarf_tag(in_die) == DW_TAG_inlined_subroutine) {
553 		lineno = die_get_call_lineno(in_die);
554 		if (lineno > 0 && dwarf_entrypc(in_die, &addr) == 0) {
555 			lw->retval = lw->handler(lw->fname, lineno, addr,
556 						 lw->data);
557 			if (lw->retval != 0)
558 				return DIE_FIND_CB_FOUND;
559 		}
560 	}
561 	return DIE_FIND_CB_SIBLING;
562 }
563 
564 /* Walk on lines of blocks included in given DIE */
__die_walk_funclines(Dwarf_Die * sp_die,line_walk_handler_t handler,void * data)565 static int __die_walk_funclines(Dwarf_Die *sp_die,
566 				line_walk_handler_t handler, void *data)
567 {
568 	struct __line_walk_param lw = {
569 		.handler = handler,
570 		.data = data,
571 		.retval = 0,
572 	};
573 	Dwarf_Die die_mem;
574 	Dwarf_Addr addr;
575 	int lineno;
576 
577 	/* Handle function declaration line */
578 	lw.fname = dwarf_decl_file(sp_die);
579 	if (lw.fname && dwarf_decl_line(sp_die, &lineno) == 0 &&
580 	    dwarf_entrypc(sp_die, &addr) == 0) {
581 		lw.retval = handler(lw.fname, lineno, addr, data);
582 		if (lw.retval != 0)
583 			goto done;
584 	}
585 	die_find_child(sp_die, __die_walk_funclines_cb, &lw, &die_mem);
586 done:
587 	return lw.retval;
588 }
589 
__die_walk_culines_cb(Dwarf_Die * sp_die,void * data)590 static int __die_walk_culines_cb(Dwarf_Die *sp_die, void *data)
591 {
592 	struct __line_walk_param *lw = data;
593 
594 	lw->retval = __die_walk_funclines(sp_die, lw->handler, lw->data);
595 	if (lw->retval != 0)
596 		return DWARF_CB_ABORT;
597 
598 	return DWARF_CB_OK;
599 }
600 
601 /*
602  * Walk on lines inside given PDIE. If the PDIE is subprogram, walk only on
603  * the lines inside the subprogram, otherwise PDIE must be a CU DIE.
604  */
die_walk_lines(Dwarf_Die * pdie,line_walk_handler_t handler,void * data)605 static int die_walk_lines(Dwarf_Die *pdie, line_walk_handler_t handler,
606 			  void *data)
607 {
608 	Dwarf_Lines *lines;
609 	Dwarf_Line *line;
610 	Dwarf_Addr addr;
611 	const char *fname;
612 	int lineno, ret = 0;
613 	Dwarf_Die die_mem, *cu_die;
614 	size_t nlines, i;
615 
616 	/* Get the CU die */
617 	if (dwarf_tag(pdie) == DW_TAG_subprogram)
618 		cu_die = dwarf_diecu(pdie, &die_mem, NULL, NULL);
619 	else
620 		cu_die = pdie;
621 	if (!cu_die) {
622 		pr_debug2("Failed to get CU from subprogram\n");
623 		return -EINVAL;
624 	}
625 
626 	/* Get lines list in the CU */
627 	if (dwarf_getsrclines(cu_die, &lines, &nlines) != 0) {
628 		pr_debug2("Failed to get source lines on this CU.\n");
629 		return -ENOENT;
630 	}
631 	pr_debug2("Get %zd lines from this CU\n", nlines);
632 
633 	/* Walk on the lines on lines list */
634 	for (i = 0; i < nlines; i++) {
635 		line = dwarf_onesrcline(lines, i);
636 		if (line == NULL ||
637 		    dwarf_lineno(line, &lineno) != 0 ||
638 		    dwarf_lineaddr(line, &addr) != 0) {
639 			pr_debug2("Failed to get line info. "
640 				  "Possible error in debuginfo.\n");
641 			continue;
642 		}
643 		/* Filter lines based on address */
644 		if (pdie != cu_die)
645 			/*
646 			 * Address filtering
647 			 * The line is included in given function, and
648 			 * no inline block includes it.
649 			 */
650 			if (!dwarf_haspc(pdie, addr) ||
651 			    die_find_inlinefunc(pdie, addr, &die_mem))
652 				continue;
653 		/* Get source line */
654 		fname = dwarf_linesrc(line, NULL, NULL);
655 
656 		ret = handler(fname, lineno, addr, data);
657 		if (ret != 0)
658 			return ret;
659 	}
660 
661 	/*
662 	 * Dwarf lines doesn't include function declarations and inlined
663 	 * subroutines. We have to check functions list or given function.
664 	 */
665 	if (pdie != cu_die)
666 		ret = __die_walk_funclines(pdie, handler, data);
667 	else {
668 		struct __line_walk_param param = {
669 			.handler = handler,
670 			.data = data,
671 			.retval = 0,
672 		};
673 		dwarf_getfuncs(cu_die, __die_walk_culines_cb, &param, 0);
674 		ret = param.retval;
675 	}
676 
677 	return ret;
678 }
679 
680 struct __find_variable_param {
681 	const char *name;
682 	Dwarf_Addr addr;
683 };
684 
__die_find_variable_cb(Dwarf_Die * die_mem,void * data)685 static int __die_find_variable_cb(Dwarf_Die *die_mem, void *data)
686 {
687 	struct __find_variable_param *fvp = data;
688 	int tag;
689 
690 	tag = dwarf_tag(die_mem);
691 	if ((tag == DW_TAG_formal_parameter ||
692 	     tag == DW_TAG_variable) &&
693 	    die_compare_name(die_mem, fvp->name))
694 		return DIE_FIND_CB_FOUND;
695 
696 	if (dwarf_haspc(die_mem, fvp->addr))
697 		return DIE_FIND_CB_CONTINUE;
698 	else
699 		return DIE_FIND_CB_SIBLING;
700 }
701 
702 /* Find a variable called 'name' at given address */
die_find_variable_at(Dwarf_Die * sp_die,const char * name,Dwarf_Addr addr,Dwarf_Die * die_mem)703 static Dwarf_Die *die_find_variable_at(Dwarf_Die *sp_die, const char *name,
704 				       Dwarf_Addr addr, Dwarf_Die *die_mem)
705 {
706 	struct __find_variable_param fvp = { .name = name, .addr = addr};
707 
708 	return die_find_child(sp_die, __die_find_variable_cb, (void *)&fvp,
709 			      die_mem);
710 }
711 
__die_find_member_cb(Dwarf_Die * die_mem,void * data)712 static int __die_find_member_cb(Dwarf_Die *die_mem, void *data)
713 {
714 	const char *name = data;
715 
716 	if ((dwarf_tag(die_mem) == DW_TAG_member) &&
717 	    die_compare_name(die_mem, name))
718 		return DIE_FIND_CB_FOUND;
719 
720 	return DIE_FIND_CB_SIBLING;
721 }
722 
723 /* Find a member called 'name' */
die_find_member(Dwarf_Die * st_die,const char * name,Dwarf_Die * die_mem)724 static Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name,
725 				  Dwarf_Die *die_mem)
726 {
727 	return die_find_child(st_die, __die_find_member_cb, (void *)name,
728 			      die_mem);
729 }
730 
731 /* Get the name of given variable DIE */
die_get_typename(Dwarf_Die * vr_die,char * buf,int len)732 static int die_get_typename(Dwarf_Die *vr_die, char *buf, int len)
733 {
734 	Dwarf_Die type;
735 	int tag, ret, ret2;
736 	const char *tmp = "";
737 
738 	if (__die_get_real_type(vr_die, &type) == NULL)
739 		return -ENOENT;
740 
741 	tag = dwarf_tag(&type);
742 	if (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)
743 		tmp = "*";
744 	else if (tag == DW_TAG_subroutine_type) {
745 		/* Function pointer */
746 		ret = snprintf(buf, len, "(function_type)");
747 		return (ret >= len) ? -E2BIG : ret;
748 	} else {
749 		if (!dwarf_diename(&type))
750 			return -ENOENT;
751 		if (tag == DW_TAG_union_type)
752 			tmp = "union ";
753 		else if (tag == DW_TAG_structure_type)
754 			tmp = "struct ";
755 		/* Write a base name */
756 		ret = snprintf(buf, len, "%s%s", tmp, dwarf_diename(&type));
757 		return (ret >= len) ? -E2BIG : ret;
758 	}
759 	ret = die_get_typename(&type, buf, len);
760 	if (ret > 0) {
761 		ret2 = snprintf(buf + ret, len - ret, "%s", tmp);
762 		ret = (ret2 >= len - ret) ? -E2BIG : ret2 + ret;
763 	}
764 	return ret;
765 }
766 
767 /* Get the name and type of given variable DIE, stored as "type\tname" */
die_get_varname(Dwarf_Die * vr_die,char * buf,int len)768 static int die_get_varname(Dwarf_Die *vr_die, char *buf, int len)
769 {
770 	int ret, ret2;
771 
772 	ret = die_get_typename(vr_die, buf, len);
773 	if (ret < 0) {
774 		pr_debug("Failed to get type, make it unknown.\n");
775 		ret = snprintf(buf, len, "(unknown_type)");
776 	}
777 	if (ret > 0) {
778 		ret2 = snprintf(buf + ret, len - ret, "\t%s",
779 				dwarf_diename(vr_die));
780 		ret = (ret2 >= len - ret) ? -E2BIG : ret2 + ret;
781 	}
782 	return ret;
783 }
784 
785 /*
786  * Probe finder related functions
787  */
788 
alloc_trace_arg_ref(long offs)789 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
790 {
791 	struct probe_trace_arg_ref *ref;
792 	ref = zalloc(sizeof(struct probe_trace_arg_ref));
793 	if (ref != NULL)
794 		ref->offset = offs;
795 	return ref;
796 }
797 
798 /*
799  * Convert a location into trace_arg.
800  * If tvar == NULL, this just checks variable can be converted.
801  */
convert_variable_location(Dwarf_Die * vr_die,Dwarf_Addr addr,Dwarf_Op * fb_ops,struct probe_trace_arg * tvar)802 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
803 				     Dwarf_Op *fb_ops,
804 				     struct probe_trace_arg *tvar)
805 {
806 	Dwarf_Attribute attr;
807 	Dwarf_Op *op;
808 	size_t nops;
809 	unsigned int regn;
810 	Dwarf_Word offs = 0;
811 	bool ref = false;
812 	const char *regs;
813 	int ret;
814 
815 	if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
816 		goto static_var;
817 
818 	/* TODO: handle more than 1 exprs */
819 	if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL ||
820 	    dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0 ||
821 	    nops == 0) {
822 		/* TODO: Support const_value */
823 		return -ENOENT;
824 	}
825 
826 	if (op->atom == DW_OP_addr) {
827 static_var:
828 		if (!tvar)
829 			return 0;
830 		/* Static variables on memory (not stack), make @varname */
831 		ret = strlen(dwarf_diename(vr_die));
832 		tvar->value = zalloc(ret + 2);
833 		if (tvar->value == NULL)
834 			return -ENOMEM;
835 		snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
836 		tvar->ref = alloc_trace_arg_ref((long)offs);
837 		if (tvar->ref == NULL)
838 			return -ENOMEM;
839 		return 0;
840 	}
841 
842 	/* If this is based on frame buffer, set the offset */
843 	if (op->atom == DW_OP_fbreg) {
844 		if (fb_ops == NULL)
845 			return -ENOTSUP;
846 		ref = true;
847 		offs = op->number;
848 		op = &fb_ops[0];
849 	}
850 
851 	if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
852 		regn = op->atom - DW_OP_breg0;
853 		offs += op->number;
854 		ref = true;
855 	} else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
856 		regn = op->atom - DW_OP_reg0;
857 	} else if (op->atom == DW_OP_bregx) {
858 		regn = op->number;
859 		offs += op->number2;
860 		ref = true;
861 	} else if (op->atom == DW_OP_regx) {
862 		regn = op->number;
863 	} else {
864 		pr_debug("DW_OP %x is not supported.\n", op->atom);
865 		return -ENOTSUP;
866 	}
867 
868 	if (!tvar)
869 		return 0;
870 
871 	regs = get_arch_regstr(regn);
872 	if (!regs) {
873 		/* This should be a bug in DWARF or this tool */
874 		pr_warning("Mapping for the register number %u "
875 			   "missing on this architecture.\n", regn);
876 		return -ERANGE;
877 	}
878 
879 	tvar->value = strdup(regs);
880 	if (tvar->value == NULL)
881 		return -ENOMEM;
882 
883 	if (ref) {
884 		tvar->ref = alloc_trace_arg_ref((long)offs);
885 		if (tvar->ref == NULL)
886 			return -ENOMEM;
887 	}
888 	return 0;
889 }
890 
891 #define BYTES_TO_BITS(nb)	((nb) * BITS_PER_LONG / sizeof(long))
892 
convert_variable_type(Dwarf_Die * vr_die,struct probe_trace_arg * tvar,const char * cast)893 static int convert_variable_type(Dwarf_Die *vr_die,
894 				 struct probe_trace_arg *tvar,
895 				 const char *cast)
896 {
897 	struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
898 	Dwarf_Die type;
899 	char buf[16];
900 	int ret;
901 
902 	/* TODO: check all types */
903 	if (cast && strcmp(cast, "string") != 0) {
904 		/* Non string type is OK */
905 		tvar->type = strdup(cast);
906 		return (tvar->type == NULL) ? -ENOMEM : 0;
907 	}
908 
909 	if (die_get_bit_size(vr_die) != 0) {
910 		/* This is a bitfield */
911 		ret = snprintf(buf, 16, "b%d@%d/%zd", die_get_bit_size(vr_die),
912 				die_get_bit_offset(vr_die),
913 				BYTES_TO_BITS(die_get_byte_size(vr_die)));
914 		goto formatted;
915 	}
916 
917 	if (die_get_real_type(vr_die, &type) == NULL) {
918 		pr_warning("Failed to get a type information of %s.\n",
919 			   dwarf_diename(vr_die));
920 		return -ENOENT;
921 	}
922 
923 	pr_debug("%s type is %s.\n",
924 		 dwarf_diename(vr_die), dwarf_diename(&type));
925 
926 	if (cast && strcmp(cast, "string") == 0) {	/* String type */
927 		ret = dwarf_tag(&type);
928 		if (ret != DW_TAG_pointer_type &&
929 		    ret != DW_TAG_array_type) {
930 			pr_warning("Failed to cast into string: "
931 				   "%s(%s) is not a pointer nor array.\n",
932 				   dwarf_diename(vr_die), dwarf_diename(&type));
933 			return -EINVAL;
934 		}
935 		if (ret == DW_TAG_pointer_type) {
936 			if (die_get_real_type(&type, &type) == NULL) {
937 				pr_warning("Failed to get a type"
938 					   " information.\n");
939 				return -ENOENT;
940 			}
941 			while (*ref_ptr)
942 				ref_ptr = &(*ref_ptr)->next;
943 			/* Add new reference with offset +0 */
944 			*ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
945 			if (*ref_ptr == NULL) {
946 				pr_warning("Out of memory error\n");
947 				return -ENOMEM;
948 			}
949 		}
950 		if (!die_compare_name(&type, "char") &&
951 		    !die_compare_name(&type, "unsigned char")) {
952 			pr_warning("Failed to cast into string: "
953 				   "%s is not (unsigned) char *.\n",
954 				   dwarf_diename(vr_die));
955 			return -EINVAL;
956 		}
957 		tvar->type = strdup(cast);
958 		return (tvar->type == NULL) ? -ENOMEM : 0;
959 	}
960 
961 	ret = BYTES_TO_BITS(die_get_byte_size(&type));
962 	if (!ret)
963 		/* No size ... try to use default type */
964 		return 0;
965 
966 	/* Check the bitwidth */
967 	if (ret > MAX_BASIC_TYPE_BITS) {
968 		pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
969 			dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
970 		ret = MAX_BASIC_TYPE_BITS;
971 	}
972 	ret = snprintf(buf, 16, "%c%d",
973 		       die_is_signed_type(&type) ? 's' : 'u', ret);
974 
975 formatted:
976 	if (ret < 0 || ret >= 16) {
977 		if (ret >= 16)
978 			ret = -E2BIG;
979 		pr_warning("Failed to convert variable type: %s\n",
980 			   strerror(-ret));
981 		return ret;
982 	}
983 	tvar->type = strdup(buf);
984 	if (tvar->type == NULL)
985 		return -ENOMEM;
986 	return 0;
987 }
988 
convert_variable_fields(Dwarf_Die * vr_die,const char * varname,struct perf_probe_arg_field * field,struct probe_trace_arg_ref ** ref_ptr,Dwarf_Die * die_mem)989 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
990 				    struct perf_probe_arg_field *field,
991 				    struct probe_trace_arg_ref **ref_ptr,
992 				    Dwarf_Die *die_mem)
993 {
994 	struct probe_trace_arg_ref *ref = *ref_ptr;
995 	Dwarf_Die type;
996 	Dwarf_Word offs;
997 	int ret, tag;
998 
999 	pr_debug("converting %s in %s\n", field->name, varname);
1000 	if (die_get_real_type(vr_die, &type) == NULL) {
1001 		pr_warning("Failed to get the type of %s.\n", varname);
1002 		return -ENOENT;
1003 	}
1004 	pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
1005 	tag = dwarf_tag(&type);
1006 
1007 	if (field->name[0] == '[' &&
1008 	    (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
1009 		if (field->next)
1010 			/* Save original type for next field */
1011 			memcpy(die_mem, &type, sizeof(*die_mem));
1012 		/* Get the type of this array */
1013 		if (die_get_real_type(&type, &type) == NULL) {
1014 			pr_warning("Failed to get the type of %s.\n", varname);
1015 			return -ENOENT;
1016 		}
1017 		pr_debug2("Array real type: (%x)\n",
1018 			 (unsigned)dwarf_dieoffset(&type));
1019 		if (tag == DW_TAG_pointer_type) {
1020 			ref = zalloc(sizeof(struct probe_trace_arg_ref));
1021 			if (ref == NULL)
1022 				return -ENOMEM;
1023 			if (*ref_ptr)
1024 				(*ref_ptr)->next = ref;
1025 			else
1026 				*ref_ptr = ref;
1027 		}
1028 		ref->offset += die_get_byte_size(&type) * field->index;
1029 		if (!field->next)
1030 			/* Save vr_die for converting types */
1031 			memcpy(die_mem, vr_die, sizeof(*die_mem));
1032 		goto next;
1033 	} else if (tag == DW_TAG_pointer_type) {
1034 		/* Check the pointer and dereference */
1035 		if (!field->ref) {
1036 			pr_err("Semantic error: %s must be referred by '->'\n",
1037 			       field->name);
1038 			return -EINVAL;
1039 		}
1040 		/* Get the type pointed by this pointer */
1041 		if (die_get_real_type(&type, &type) == NULL) {
1042 			pr_warning("Failed to get the type of %s.\n", varname);
1043 			return -ENOENT;
1044 		}
1045 		/* Verify it is a data structure  */
1046 		if (dwarf_tag(&type) != DW_TAG_structure_type) {
1047 			pr_warning("%s is not a data structure.\n", varname);
1048 			return -EINVAL;
1049 		}
1050 
1051 		ref = zalloc(sizeof(struct probe_trace_arg_ref));
1052 		if (ref == NULL)
1053 			return -ENOMEM;
1054 		if (*ref_ptr)
1055 			(*ref_ptr)->next = ref;
1056 		else
1057 			*ref_ptr = ref;
1058 	} else {
1059 		/* Verify it is a data structure  */
1060 		if (tag != DW_TAG_structure_type) {
1061 			pr_warning("%s is not a data structure.\n", varname);
1062 			return -EINVAL;
1063 		}
1064 		if (field->name[0] == '[') {
1065 			pr_err("Semantic error: %s is not a pointor"
1066 			       " nor array.\n", varname);
1067 			return -EINVAL;
1068 		}
1069 		if (field->ref) {
1070 			pr_err("Semantic error: %s must be referred by '.'\n",
1071 			       field->name);
1072 			return -EINVAL;
1073 		}
1074 		if (!ref) {
1075 			pr_warning("Structure on a register is not "
1076 				   "supported yet.\n");
1077 			return -ENOTSUP;
1078 		}
1079 	}
1080 
1081 	if (die_find_member(&type, field->name, die_mem) == NULL) {
1082 		pr_warning("%s(tyep:%s) has no member %s.\n", varname,
1083 			   dwarf_diename(&type), field->name);
1084 		return -EINVAL;
1085 	}
1086 
1087 	/* Get the offset of the field */
1088 	ret = die_get_data_member_location(die_mem, &offs);
1089 	if (ret < 0) {
1090 		pr_warning("Failed to get the offset of %s.\n", field->name);
1091 		return ret;
1092 	}
1093 	ref->offset += (long)offs;
1094 
1095 next:
1096 	/* Converting next field */
1097 	if (field->next)
1098 		return convert_variable_fields(die_mem, field->name,
1099 					field->next, &ref, die_mem);
1100 	else
1101 		return 0;
1102 }
1103 
1104 /* Show a variables in kprobe event format */
convert_variable(Dwarf_Die * vr_die,struct probe_finder * pf)1105 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
1106 {
1107 	Dwarf_Die die_mem;
1108 	int ret;
1109 
1110 	pr_debug("Converting variable %s into trace event.\n",
1111 		 dwarf_diename(vr_die));
1112 
1113 	ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
1114 					pf->tvar);
1115 	if (ret == -ENOENT)
1116 		pr_err("Failed to find the location of %s at this address.\n"
1117 		       " Perhaps, it has been optimized out.\n", pf->pvar->var);
1118 	else if (ret == -ENOTSUP)
1119 		pr_err("Sorry, we don't support this variable location yet.\n");
1120 	else if (pf->pvar->field) {
1121 		ret = convert_variable_fields(vr_die, pf->pvar->var,
1122 					      pf->pvar->field, &pf->tvar->ref,
1123 					      &die_mem);
1124 		vr_die = &die_mem;
1125 	}
1126 	if (ret == 0)
1127 		ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
1128 	/* *expr will be cached in libdw. Don't free it. */
1129 	return ret;
1130 }
1131 
1132 /* Find a variable in a subprogram die */
find_variable(Dwarf_Die * sp_die,struct probe_finder * pf)1133 static int find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
1134 {
1135 	Dwarf_Die vr_die, *scopes;
1136 	char buf[32], *ptr;
1137 	int ret, nscopes;
1138 
1139 	if (!is_c_varname(pf->pvar->var)) {
1140 		/* Copy raw parameters */
1141 		pf->tvar->value = strdup(pf->pvar->var);
1142 		if (pf->tvar->value == NULL)
1143 			return -ENOMEM;
1144 		if (pf->pvar->type) {
1145 			pf->tvar->type = strdup(pf->pvar->type);
1146 			if (pf->tvar->type == NULL)
1147 				return -ENOMEM;
1148 		}
1149 		if (pf->pvar->name) {
1150 			pf->tvar->name = strdup(pf->pvar->name);
1151 			if (pf->tvar->name == NULL)
1152 				return -ENOMEM;
1153 		} else
1154 			pf->tvar->name = NULL;
1155 		return 0;
1156 	}
1157 
1158 	if (pf->pvar->name)
1159 		pf->tvar->name = strdup(pf->pvar->name);
1160 	else {
1161 		ret = synthesize_perf_probe_arg(pf->pvar, buf, 32);
1162 		if (ret < 0)
1163 			return ret;
1164 		ptr = strchr(buf, ':');	/* Change type separator to _ */
1165 		if (ptr)
1166 			*ptr = '_';
1167 		pf->tvar->name = strdup(buf);
1168 	}
1169 	if (pf->tvar->name == NULL)
1170 		return -ENOMEM;
1171 
1172 	pr_debug("Searching '%s' variable in context.\n",
1173 		 pf->pvar->var);
1174 	/* Search child die for local variables and parameters. */
1175 	if (die_find_variable_at(sp_die, pf->pvar->var, pf->addr, &vr_die))
1176 		ret = convert_variable(&vr_die, pf);
1177 	else {
1178 		/* Search upper class */
1179 		nscopes = dwarf_getscopes_die(sp_die, &scopes);
1180 		while (nscopes-- > 1) {
1181 			pr_debug("Searching variables in %s\n",
1182 				 dwarf_diename(&scopes[nscopes]));
1183 			/* We should check this scope, so give dummy address */
1184 			if (die_find_variable_at(&scopes[nscopes],
1185 						 pf->pvar->var, 0,
1186 						 &vr_die)) {
1187 				ret = convert_variable(&vr_die, pf);
1188 				goto found;
1189 			}
1190 		}
1191 		if (scopes)
1192 			free(scopes);
1193 		ret = -ENOENT;
1194 	}
1195 found:
1196 	if (ret < 0)
1197 		pr_warning("Failed to find '%s' in this function.\n",
1198 			   pf->pvar->var);
1199 	return ret;
1200 }
1201 
1202 /* Convert subprogram DIE to trace point */
convert_to_trace_point(Dwarf_Die * sp_die,Dwarf_Addr paddr,bool retprobe,struct probe_trace_point * tp)1203 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwarf_Addr paddr,
1204 				  bool retprobe, struct probe_trace_point *tp)
1205 {
1206 	Dwarf_Addr eaddr;
1207 	const char *name;
1208 
1209 	/* Copy the name of probe point */
1210 	name = dwarf_diename(sp_die);
1211 	if (name) {
1212 		if (dwarf_entrypc(sp_die, &eaddr) != 0) {
1213 			pr_warning("Failed to get entry address of %s\n",
1214 				   dwarf_diename(sp_die));
1215 			return -ENOENT;
1216 		}
1217 		tp->symbol = strdup(name);
1218 		if (tp->symbol == NULL)
1219 			return -ENOMEM;
1220 		tp->offset = (unsigned long)(paddr - eaddr);
1221 	} else
1222 		/* This function has no name. */
1223 		tp->offset = (unsigned long)paddr;
1224 
1225 	/* Return probe must be on the head of a subprogram */
1226 	if (retprobe) {
1227 		if (eaddr != paddr) {
1228 			pr_warning("Return probe must be on the head of"
1229 				   " a real function.\n");
1230 			return -EINVAL;
1231 		}
1232 		tp->retprobe = true;
1233 	}
1234 
1235 	return 0;
1236 }
1237 
1238 /* Call probe_finder callback with real subprogram DIE */
call_probe_finder(Dwarf_Die * sp_die,struct probe_finder * pf)1239 static int call_probe_finder(Dwarf_Die *sp_die, struct probe_finder *pf)
1240 {
1241 	Dwarf_Die die_mem;
1242 	Dwarf_Attribute fb_attr;
1243 	size_t nops;
1244 	int ret;
1245 
1246 	/* If no real subprogram, find a real one */
1247 	if (!sp_die || dwarf_tag(sp_die) != DW_TAG_subprogram) {
1248 		sp_die = die_find_real_subprogram(&pf->cu_die,
1249 						  pf->addr, &die_mem);
1250 		if (!sp_die) {
1251 			pr_warning("Failed to find probe point in any "
1252 				   "functions.\n");
1253 			return -ENOENT;
1254 		}
1255 	}
1256 
1257 	/* Get the frame base attribute/ops */
1258 	dwarf_attr(sp_die, DW_AT_frame_base, &fb_attr);
1259 	ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
1260 	if (ret <= 0 || nops == 0) {
1261 		pf->fb_ops = NULL;
1262 #if _ELFUTILS_PREREQ(0, 142)
1263 	} else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
1264 		   pf->cfi != NULL) {
1265 		Dwarf_Frame *frame;
1266 		if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
1267 		    dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
1268 			pr_warning("Failed to get call frame on 0x%jx\n",
1269 				   (uintmax_t)pf->addr);
1270 			return -ENOENT;
1271 		}
1272 #endif
1273 	}
1274 
1275 	/* Call finder's callback handler */
1276 	ret = pf->callback(sp_die, pf);
1277 
1278 	/* *pf->fb_ops will be cached in libdw. Don't free it. */
1279 	pf->fb_ops = NULL;
1280 
1281 	return ret;
1282 }
1283 
probe_point_line_walker(const char * fname,int lineno,Dwarf_Addr addr,void * data)1284 static int probe_point_line_walker(const char *fname, int lineno,
1285 				   Dwarf_Addr addr, void *data)
1286 {
1287 	struct probe_finder *pf = data;
1288 	int ret;
1289 
1290 	if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
1291 		return 0;
1292 
1293 	pf->addr = addr;
1294 	ret = call_probe_finder(NULL, pf);
1295 
1296 	/* Continue if no error, because the line will be in inline function */
1297 	return ret < 0 ? ret : 0;
1298 }
1299 
1300 /* Find probe point from its line number */
find_probe_point_by_line(struct probe_finder * pf)1301 static int find_probe_point_by_line(struct probe_finder *pf)
1302 {
1303 	return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
1304 }
1305 
1306 /* Find lines which match lazy pattern */
find_lazy_match_lines(struct list_head * head,const char * fname,const char * pat)1307 static int find_lazy_match_lines(struct list_head *head,
1308 				 const char *fname, const char *pat)
1309 {
1310 	FILE *fp;
1311 	char *line = NULL;
1312 	size_t line_len;
1313 	ssize_t len;
1314 	int count = 0, linenum = 1;
1315 
1316 	fp = fopen(fname, "r");
1317 	if (!fp) {
1318 		pr_warning("Failed to open %s: %s\n", fname, strerror(errno));
1319 		return -errno;
1320 	}
1321 
1322 	while ((len = getline(&line, &line_len, fp)) > 0) {
1323 
1324 		if (line[len - 1] == '\n')
1325 			line[len - 1] = '\0';
1326 
1327 		if (strlazymatch(line, pat)) {
1328 			line_list__add_line(head, linenum);
1329 			count++;
1330 		}
1331 		linenum++;
1332 	}
1333 
1334 	if (ferror(fp))
1335 		count = -errno;
1336 	free(line);
1337 	fclose(fp);
1338 
1339 	if (count == 0)
1340 		pr_debug("No matched lines found in %s.\n", fname);
1341 	return count;
1342 }
1343 
probe_point_lazy_walker(const char * fname,int lineno,Dwarf_Addr addr,void * data)1344 static int probe_point_lazy_walker(const char *fname, int lineno,
1345 				   Dwarf_Addr addr, void *data)
1346 {
1347 	struct probe_finder *pf = data;
1348 	int ret;
1349 
1350 	if (!line_list__has_line(&pf->lcache, lineno) ||
1351 	    strtailcmp(fname, pf->fname) != 0)
1352 		return 0;
1353 
1354 	pr_debug("Probe line found: line:%d addr:0x%llx\n",
1355 		 lineno, (unsigned long long)addr);
1356 	pf->addr = addr;
1357 	ret = call_probe_finder(NULL, pf);
1358 
1359 	/*
1360 	 * Continue if no error, because the lazy pattern will match
1361 	 * to other lines
1362 	 */
1363 	return ret < 0 ? ret : 0;
1364 }
1365 
1366 /* Find probe points from lazy pattern  */
find_probe_point_lazy(Dwarf_Die * sp_die,struct probe_finder * pf)1367 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
1368 {
1369 	int ret = 0;
1370 
1371 	if (list_empty(&pf->lcache)) {
1372 		/* Matching lazy line pattern */
1373 		ret = find_lazy_match_lines(&pf->lcache, pf->fname,
1374 					    pf->pev->point.lazy_line);
1375 		if (ret <= 0)
1376 			return ret;
1377 	}
1378 
1379 	return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
1380 }
1381 
1382 /* Callback parameter with return value */
1383 struct dwarf_callback_param {
1384 	void *data;
1385 	int retval;
1386 };
1387 
probe_point_inline_cb(Dwarf_Die * in_die,void * data)1388 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
1389 {
1390 	struct dwarf_callback_param *param = data;
1391 	struct probe_finder *pf = param->data;
1392 	struct perf_probe_point *pp = &pf->pev->point;
1393 	Dwarf_Addr addr;
1394 
1395 	if (pp->lazy_line)
1396 		param->retval = find_probe_point_lazy(in_die, pf);
1397 	else {
1398 		/* Get probe address */
1399 		if (dwarf_entrypc(in_die, &addr) != 0) {
1400 			pr_warning("Failed to get entry address of %s.\n",
1401 				   dwarf_diename(in_die));
1402 			param->retval = -ENOENT;
1403 			return DWARF_CB_ABORT;
1404 		}
1405 		pf->addr = addr;
1406 		pf->addr += pp->offset;
1407 		pr_debug("found inline addr: 0x%jx\n",
1408 			 (uintmax_t)pf->addr);
1409 
1410 		param->retval = call_probe_finder(in_die, pf);
1411 		if (param->retval < 0)
1412 			return DWARF_CB_ABORT;
1413 	}
1414 
1415 	return DWARF_CB_OK;
1416 }
1417 
1418 /* Search function from function name */
probe_point_search_cb(Dwarf_Die * sp_die,void * data)1419 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
1420 {
1421 	struct dwarf_callback_param *param = data;
1422 	struct probe_finder *pf = param->data;
1423 	struct perf_probe_point *pp = &pf->pev->point;
1424 
1425 	/* Check tag and diename */
1426 	if (dwarf_tag(sp_die) != DW_TAG_subprogram ||
1427 	    !die_compare_name(sp_die, pp->function))
1428 		return DWARF_CB_OK;
1429 
1430 	/* Check declared file */
1431 	if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
1432 		return DWARF_CB_OK;
1433 
1434 	pf->fname = dwarf_decl_file(sp_die);
1435 	if (pp->line) { /* Function relative line */
1436 		dwarf_decl_line(sp_die, &pf->lno);
1437 		pf->lno += pp->line;
1438 		param->retval = find_probe_point_by_line(pf);
1439 	} else if (!dwarf_func_inline(sp_die)) {
1440 		/* Real function */
1441 		if (pp->lazy_line)
1442 			param->retval = find_probe_point_lazy(sp_die, pf);
1443 		else {
1444 			if (dwarf_entrypc(sp_die, &pf->addr) != 0) {
1445 				pr_warning("Failed to get entry address of "
1446 					   "%s.\n", dwarf_diename(sp_die));
1447 				param->retval = -ENOENT;
1448 				return DWARF_CB_ABORT;
1449 			}
1450 			pf->addr += pp->offset;
1451 			/* TODO: Check the address in this function */
1452 			param->retval = call_probe_finder(sp_die, pf);
1453 		}
1454 	} else {
1455 		struct dwarf_callback_param _param = {.data = (void *)pf,
1456 						      .retval = 0};
1457 		/* Inlined function: search instances */
1458 		dwarf_func_inline_instances(sp_die, probe_point_inline_cb,
1459 					    &_param);
1460 		param->retval = _param.retval;
1461 	}
1462 
1463 	return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1464 }
1465 
find_probe_point_by_func(struct probe_finder * pf)1466 static int find_probe_point_by_func(struct probe_finder *pf)
1467 {
1468 	struct dwarf_callback_param _param = {.data = (void *)pf,
1469 					      .retval = 0};
1470 	dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1471 	return _param.retval;
1472 }
1473 
1474 /* Find probe points from debuginfo */
find_probes(int fd,struct probe_finder * pf)1475 static int find_probes(int fd, struct probe_finder *pf)
1476 {
1477 	struct perf_probe_point *pp = &pf->pev->point;
1478 	Dwarf_Off off, noff;
1479 	size_t cuhl;
1480 	Dwarf_Die *diep;
1481 	Dwarf *dbg = NULL;
1482 	Dwfl *dwfl;
1483 	Dwarf_Addr bias;	/* Currently ignored */
1484 	int ret = 0;
1485 
1486 	dbg = dwfl_init_offline_dwarf(fd, &dwfl, &bias);
1487 	if (!dbg) {
1488 		pr_warning("No debug information found in the vmlinux - "
1489 			"please rebuild with CONFIG_DEBUG_INFO=y.\n");
1490 		close(fd);	/* Without dwfl_end(), fd isn't closed. */
1491 		return -EBADF;
1492 	}
1493 
1494 #if _ELFUTILS_PREREQ(0, 142)
1495 	/* Get the call frame information from this dwarf */
1496 	pf->cfi = dwarf_getcfi(dbg);
1497 #endif
1498 
1499 	off = 0;
1500 	line_list__init(&pf->lcache);
1501 	/* Loop on CUs (Compilation Unit) */
1502 	while (!dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1503 		/* Get the DIE(Debugging Information Entry) of this CU */
1504 		diep = dwarf_offdie(dbg, off + cuhl, &pf->cu_die);
1505 		if (!diep)
1506 			continue;
1507 
1508 		/* Check if target file is included. */
1509 		if (pp->file)
1510 			pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1511 		else
1512 			pf->fname = NULL;
1513 
1514 		if (!pp->file || pf->fname) {
1515 			if (pp->function)
1516 				ret = find_probe_point_by_func(pf);
1517 			else if (pp->lazy_line)
1518 				ret = find_probe_point_lazy(NULL, pf);
1519 			else {
1520 				pf->lno = pp->line;
1521 				ret = find_probe_point_by_line(pf);
1522 			}
1523 			if (ret < 0)
1524 				break;
1525 		}
1526 		off = noff;
1527 	}
1528 	line_list__free(&pf->lcache);
1529 	if (dwfl)
1530 		dwfl_end(dwfl);
1531 
1532 	return ret;
1533 }
1534 
1535 /* Add a found probe point into trace event list */
add_probe_trace_event(Dwarf_Die * sp_die,struct probe_finder * pf)1536 static int add_probe_trace_event(Dwarf_Die *sp_die, struct probe_finder *pf)
1537 {
1538 	struct trace_event_finder *tf =
1539 			container_of(pf, struct trace_event_finder, pf);
1540 	struct probe_trace_event *tev;
1541 	int ret, i;
1542 
1543 	/* Check number of tevs */
1544 	if (tf->ntevs == tf->max_tevs) {
1545 		pr_warning("Too many( > %d) probe point found.\n",
1546 			   tf->max_tevs);
1547 		return -ERANGE;
1548 	}
1549 	tev = &tf->tevs[tf->ntevs++];
1550 
1551 	ret = convert_to_trace_point(sp_die, pf->addr, pf->pev->point.retprobe,
1552 				     &tev->point);
1553 	if (ret < 0)
1554 		return ret;
1555 
1556 	pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1557 		 tev->point.offset);
1558 
1559 	/* Find each argument */
1560 	tev->nargs = pf->pev->nargs;
1561 	tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1562 	if (tev->args == NULL)
1563 		return -ENOMEM;
1564 	for (i = 0; i < pf->pev->nargs; i++) {
1565 		pf->pvar = &pf->pev->args[i];
1566 		pf->tvar = &tev->args[i];
1567 		ret = find_variable(sp_die, pf);
1568 		if (ret != 0)
1569 			return ret;
1570 	}
1571 
1572 	return 0;
1573 }
1574 
1575 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
find_probe_trace_events(int fd,struct perf_probe_event * pev,struct probe_trace_event ** tevs,int max_tevs)1576 int find_probe_trace_events(int fd, struct perf_probe_event *pev,
1577 			    struct probe_trace_event **tevs, int max_tevs)
1578 {
1579 	struct trace_event_finder tf = {
1580 			.pf = {.pev = pev, .callback = add_probe_trace_event},
1581 			.max_tevs = max_tevs};
1582 	int ret;
1583 
1584 	/* Allocate result tevs array */
1585 	*tevs = zalloc(sizeof(struct probe_trace_event) * max_tevs);
1586 	if (*tevs == NULL)
1587 		return -ENOMEM;
1588 
1589 	tf.tevs = *tevs;
1590 	tf.ntevs = 0;
1591 
1592 	ret = find_probes(fd, &tf.pf);
1593 	if (ret < 0) {
1594 		free(*tevs);
1595 		*tevs = NULL;
1596 		return ret;
1597 	}
1598 
1599 	return (ret < 0) ? ret : tf.ntevs;
1600 }
1601 
1602 #define MAX_VAR_LEN 64
1603 
1604 /* Collect available variables in this scope */
collect_variables_cb(Dwarf_Die * die_mem,void * data)1605 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1606 {
1607 	struct available_var_finder *af = data;
1608 	struct variable_list *vl;
1609 	char buf[MAX_VAR_LEN];
1610 	int tag, ret;
1611 
1612 	vl = &af->vls[af->nvls - 1];
1613 
1614 	tag = dwarf_tag(die_mem);
1615 	if (tag == DW_TAG_formal_parameter ||
1616 	    tag == DW_TAG_variable) {
1617 		ret = convert_variable_location(die_mem, af->pf.addr,
1618 						af->pf.fb_ops, NULL);
1619 		if (ret == 0) {
1620 			ret = die_get_varname(die_mem, buf, MAX_VAR_LEN);
1621 			pr_debug2("Add new var: %s\n", buf);
1622 			if (ret > 0)
1623 				strlist__add(vl->vars, buf);
1624 		}
1625 	}
1626 
1627 	if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1628 		return DIE_FIND_CB_CONTINUE;
1629 	else
1630 		return DIE_FIND_CB_SIBLING;
1631 }
1632 
1633 /* Add a found vars into available variables list */
add_available_vars(Dwarf_Die * sp_die,struct probe_finder * pf)1634 static int add_available_vars(Dwarf_Die *sp_die, struct probe_finder *pf)
1635 {
1636 	struct available_var_finder *af =
1637 			container_of(pf, struct available_var_finder, pf);
1638 	struct variable_list *vl;
1639 	Dwarf_Die die_mem, *scopes = NULL;
1640 	int ret, nscopes;
1641 
1642 	/* Check number of tevs */
1643 	if (af->nvls == af->max_vls) {
1644 		pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1645 		return -ERANGE;
1646 	}
1647 	vl = &af->vls[af->nvls++];
1648 
1649 	ret = convert_to_trace_point(sp_die, pf->addr, pf->pev->point.retprobe,
1650 				     &vl->point);
1651 	if (ret < 0)
1652 		return ret;
1653 
1654 	pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1655 		 vl->point.offset);
1656 
1657 	/* Find local variables */
1658 	vl->vars = strlist__new(true, NULL);
1659 	if (vl->vars == NULL)
1660 		return -ENOMEM;
1661 	af->child = true;
1662 	die_find_child(sp_die, collect_variables_cb, (void *)af, &die_mem);
1663 
1664 	/* Find external variables */
1665 	if (!af->externs)
1666 		goto out;
1667 	/* Don't need to search child DIE for externs. */
1668 	af->child = false;
1669 	nscopes = dwarf_getscopes_die(sp_die, &scopes);
1670 	while (nscopes-- > 1)
1671 		die_find_child(&scopes[nscopes], collect_variables_cb,
1672 			       (void *)af, &die_mem);
1673 	if (scopes)
1674 		free(scopes);
1675 
1676 out:
1677 	if (strlist__empty(vl->vars)) {
1678 		strlist__delete(vl->vars);
1679 		vl->vars = NULL;
1680 	}
1681 
1682 	return ret;
1683 }
1684 
1685 /* Find available variables at given probe point */
find_available_vars_at(int fd,struct perf_probe_event * pev,struct variable_list ** vls,int max_vls,bool externs)1686 int find_available_vars_at(int fd, struct perf_probe_event *pev,
1687 			   struct variable_list **vls, int max_vls,
1688 			   bool externs)
1689 {
1690 	struct available_var_finder af = {
1691 			.pf = {.pev = pev, .callback = add_available_vars},
1692 			.max_vls = max_vls, .externs = externs};
1693 	int ret;
1694 
1695 	/* Allocate result vls array */
1696 	*vls = zalloc(sizeof(struct variable_list) * max_vls);
1697 	if (*vls == NULL)
1698 		return -ENOMEM;
1699 
1700 	af.vls = *vls;
1701 	af.nvls = 0;
1702 
1703 	ret = find_probes(fd, &af.pf);
1704 	if (ret < 0) {
1705 		/* Free vlist for error */
1706 		while (af.nvls--) {
1707 			if (af.vls[af.nvls].point.symbol)
1708 				free(af.vls[af.nvls].point.symbol);
1709 			if (af.vls[af.nvls].vars)
1710 				strlist__delete(af.vls[af.nvls].vars);
1711 		}
1712 		free(af.vls);
1713 		*vls = NULL;
1714 		return ret;
1715 	}
1716 
1717 	return (ret < 0) ? ret : af.nvls;
1718 }
1719 
1720 /* Reverse search */
find_perf_probe_point(unsigned long addr,struct perf_probe_point * ppt)1721 int find_perf_probe_point(unsigned long addr, struct perf_probe_point *ppt)
1722 {
1723 	Dwarf_Die cudie, spdie, indie;
1724 	Dwarf *dbg = NULL;
1725 	Dwfl *dwfl = NULL;
1726 	Dwarf_Addr _addr, baseaddr, bias = 0;
1727 	const char *fname = NULL, *func = NULL, *tmp;
1728 	int baseline = 0, lineno = 0, ret = 0;
1729 
1730 	/* Open the live linux kernel */
1731 	dbg = dwfl_init_live_kernel_dwarf(addr, &dwfl, &bias);
1732 	if (!dbg) {
1733 		pr_warning("No debug information found in the vmlinux - "
1734 			"please rebuild with CONFIG_DEBUG_INFO=y.\n");
1735 		ret = -EINVAL;
1736 		goto end;
1737 	}
1738 
1739 	/* Adjust address with bias */
1740 	addr += bias;
1741 	/* Find cu die */
1742 	if (!dwarf_addrdie(dbg, (Dwarf_Addr)addr - bias, &cudie)) {
1743 		pr_warning("Failed to find debug information for address %lx\n",
1744 			   addr);
1745 		ret = -EINVAL;
1746 		goto end;
1747 	}
1748 
1749 	/* Find a corresponding line (filename and lineno) */
1750 	cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1751 	/* Don't care whether it failed or not */
1752 
1753 	/* Find a corresponding function (name, baseline and baseaddr) */
1754 	if (die_find_real_subprogram(&cudie, (Dwarf_Addr)addr, &spdie)) {
1755 		/* Get function entry information */
1756 		tmp = dwarf_diename(&spdie);
1757 		if (!tmp ||
1758 		    dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1759 		    dwarf_decl_line(&spdie, &baseline) != 0)
1760 			goto post;
1761 		func = tmp;
1762 
1763 		if (addr == (unsigned long)baseaddr)
1764 			/* Function entry - Relative line number is 0 */
1765 			lineno = baseline;
1766 		else if (die_find_inlinefunc(&spdie, (Dwarf_Addr)addr,
1767 					     &indie)) {
1768 			if (dwarf_entrypc(&indie, &_addr) == 0 &&
1769 			    _addr == addr)
1770 				/*
1771 				 * addr is at an inline function entry.
1772 				 * In this case, lineno should be the call-site
1773 				 * line number.
1774 				 */
1775 				lineno = die_get_call_lineno(&indie);
1776 			else {
1777 				/*
1778 				 * addr is in an inline function body.
1779 				 * Since lineno points one of the lines
1780 				 * of the inline function, baseline should
1781 				 * be the entry line of the inline function.
1782 				 */
1783 				tmp = dwarf_diename(&indie);
1784 				if (tmp &&
1785 				    dwarf_decl_line(&spdie, &baseline) == 0)
1786 					func = tmp;
1787 			}
1788 		}
1789 	}
1790 
1791 post:
1792 	/* Make a relative line number or an offset */
1793 	if (lineno)
1794 		ppt->line = lineno - baseline;
1795 	else if (func)
1796 		ppt->offset = addr - (unsigned long)baseaddr;
1797 
1798 	/* Duplicate strings */
1799 	if (func) {
1800 		ppt->function = strdup(func);
1801 		if (ppt->function == NULL) {
1802 			ret = -ENOMEM;
1803 			goto end;
1804 		}
1805 	}
1806 	if (fname) {
1807 		ppt->file = strdup(fname);
1808 		if (ppt->file == NULL) {
1809 			if (ppt->function) {
1810 				free(ppt->function);
1811 				ppt->function = NULL;
1812 			}
1813 			ret = -ENOMEM;
1814 			goto end;
1815 		}
1816 	}
1817 end:
1818 	if (dwfl)
1819 		dwfl_end(dwfl);
1820 	if (ret == 0 && (fname || func))
1821 		ret = 1;	/* Found a point */
1822 	return ret;
1823 }
1824 
1825 /* Add a line and store the src path */
line_range_add_line(const char * src,unsigned int lineno,struct line_range * lr)1826 static int line_range_add_line(const char *src, unsigned int lineno,
1827 			       struct line_range *lr)
1828 {
1829 	/* Copy source path */
1830 	if (!lr->path) {
1831 		lr->path = strdup(src);
1832 		if (lr->path == NULL)
1833 			return -ENOMEM;
1834 	}
1835 	return line_list__add_line(&lr->line_list, lineno);
1836 }
1837 
line_range_walk_cb(const char * fname,int lineno,Dwarf_Addr addr __used,void * data)1838 static int line_range_walk_cb(const char *fname, int lineno,
1839 			      Dwarf_Addr addr __used,
1840 			      void *data)
1841 {
1842 	struct line_finder *lf = data;
1843 
1844 	if ((strtailcmp(fname, lf->fname) != 0) ||
1845 	    (lf->lno_s > lineno || lf->lno_e < lineno))
1846 		return 0;
1847 
1848 	if (line_range_add_line(fname, lineno, lf->lr) < 0)
1849 		return -EINVAL;
1850 
1851 	return 0;
1852 }
1853 
1854 /* Find line range from its line number */
find_line_range_by_line(Dwarf_Die * sp_die,struct line_finder * lf)1855 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1856 {
1857 	int ret;
1858 
1859 	ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1860 
1861 	/* Update status */
1862 	if (ret >= 0)
1863 		if (!list_empty(&lf->lr->line_list))
1864 			ret = lf->found = 1;
1865 		else
1866 			ret = 0;	/* Lines are not found */
1867 	else {
1868 		free(lf->lr->path);
1869 		lf->lr->path = NULL;
1870 	}
1871 	return ret;
1872 }
1873 
line_range_inline_cb(Dwarf_Die * in_die,void * data)1874 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1875 {
1876 	struct dwarf_callback_param *param = data;
1877 
1878 	param->retval = find_line_range_by_line(in_die, param->data);
1879 	return DWARF_CB_ABORT;	/* No need to find other instances */
1880 }
1881 
1882 /* Search function from function name */
line_range_search_cb(Dwarf_Die * sp_die,void * data)1883 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1884 {
1885 	struct dwarf_callback_param *param = data;
1886 	struct line_finder *lf = param->data;
1887 	struct line_range *lr = lf->lr;
1888 
1889 	/* Check declared file */
1890 	if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1891 		return DWARF_CB_OK;
1892 
1893 	if (dwarf_tag(sp_die) == DW_TAG_subprogram &&
1894 	    die_compare_name(sp_die, lr->function)) {
1895 		lf->fname = dwarf_decl_file(sp_die);
1896 		dwarf_decl_line(sp_die, &lr->offset);
1897 		pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1898 		lf->lno_s = lr->offset + lr->start;
1899 		if (lf->lno_s < 0)	/* Overflow */
1900 			lf->lno_s = INT_MAX;
1901 		lf->lno_e = lr->offset + lr->end;
1902 		if (lf->lno_e < 0)	/* Overflow */
1903 			lf->lno_e = INT_MAX;
1904 		pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1905 		lr->start = lf->lno_s;
1906 		lr->end = lf->lno_e;
1907 		if (dwarf_func_inline(sp_die)) {
1908 			struct dwarf_callback_param _param;
1909 			_param.data = (void *)lf;
1910 			_param.retval = 0;
1911 			dwarf_func_inline_instances(sp_die,
1912 						    line_range_inline_cb,
1913 						    &_param);
1914 			param->retval = _param.retval;
1915 		} else
1916 			param->retval = find_line_range_by_line(sp_die, lf);
1917 		return DWARF_CB_ABORT;
1918 	}
1919 	return DWARF_CB_OK;
1920 }
1921 
find_line_range_by_func(struct line_finder * lf)1922 static int find_line_range_by_func(struct line_finder *lf)
1923 {
1924 	struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1925 	dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1926 	return param.retval;
1927 }
1928 
find_line_range(int fd,struct line_range * lr)1929 int find_line_range(int fd, struct line_range *lr)
1930 {
1931 	struct line_finder lf = {.lr = lr, .found = 0};
1932 	int ret = 0;
1933 	Dwarf_Off off = 0, noff;
1934 	size_t cuhl;
1935 	Dwarf_Die *diep;
1936 	Dwarf *dbg = NULL;
1937 	Dwfl *dwfl;
1938 	Dwarf_Addr bias;	/* Currently ignored */
1939 	const char *comp_dir;
1940 
1941 	dbg = dwfl_init_offline_dwarf(fd, &dwfl, &bias);
1942 	if (!dbg) {
1943 		pr_warning("No debug information found in the vmlinux - "
1944 			"please rebuild with CONFIG_DEBUG_INFO=y.\n");
1945 		close(fd);	/* Without dwfl_end(), fd isn't closed. */
1946 		return -EBADF;
1947 	}
1948 
1949 	/* Loop on CUs (Compilation Unit) */
1950 	while (!lf.found && ret >= 0) {
1951 		if (dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL) != 0)
1952 			break;
1953 
1954 		/* Get the DIE(Debugging Information Entry) of this CU */
1955 		diep = dwarf_offdie(dbg, off + cuhl, &lf.cu_die);
1956 		if (!diep)
1957 			continue;
1958 
1959 		/* Check if target file is included. */
1960 		if (lr->file)
1961 			lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1962 		else
1963 			lf.fname = 0;
1964 
1965 		if (!lr->file || lf.fname) {
1966 			if (lr->function)
1967 				ret = find_line_range_by_func(&lf);
1968 			else {
1969 				lf.lno_s = lr->start;
1970 				lf.lno_e = lr->end;
1971 				ret = find_line_range_by_line(NULL, &lf);
1972 			}
1973 		}
1974 		off = noff;
1975 	}
1976 
1977 	/* Store comp_dir */
1978 	if (lf.found) {
1979 		comp_dir = cu_get_comp_dir(&lf.cu_die);
1980 		if (comp_dir) {
1981 			lr->comp_dir = strdup(comp_dir);
1982 			if (!lr->comp_dir)
1983 				ret = -ENOMEM;
1984 		}
1985 	}
1986 
1987 	pr_debug("path: %s\n", lr->path);
1988 	dwfl_end(dwfl);
1989 	return (ret < 0) ? ret : lf.found;
1990 }
1991 
1992