xref: /openbmc/linux/tools/perf/util/probe-finder.c (revision df2634f43f5106947f3735a0b61a6527a4b278cd)
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 "event.h"
37 #include "debug.h"
38 #include "util.h"
39 #include "symbol.h"
40 #include "probe-finder.h"
41 
42 /* Kprobe tracer basic type is up to u64 */
43 #define MAX_BASIC_TYPE_BITS	64
44 
45 /*
46  * Compare the tail of two strings.
47  * Return 0 if whole of either string is same as another's tail part.
48  */
49 static int strtailcmp(const char *s1, const char *s2)
50 {
51 	int i1 = strlen(s1);
52 	int i2 = strlen(s2);
53 	while (--i1 >= 0 && --i2 >= 0) {
54 		if (s1[i1] != s2[i2])
55 			return s1[i1] - s2[i2];
56 	}
57 	return 0;
58 }
59 
60 /* Line number list operations */
61 
62 /* Add a line to line number list */
63 static int line_list__add_line(struct list_head *head, int line)
64 {
65 	struct line_node *ln;
66 	struct list_head *p;
67 
68 	/* Reverse search, because new line will be the last one */
69 	list_for_each_entry_reverse(ln, head, list) {
70 		if (ln->line < line) {
71 			p = &ln->list;
72 			goto found;
73 		} else if (ln->line == line)	/* Already exist */
74 			return 1;
75 	}
76 	/* List is empty, or the smallest entry */
77 	p = head;
78 found:
79 	pr_debug("line list: add a line %u\n", line);
80 	ln = zalloc(sizeof(struct line_node));
81 	if (ln == NULL)
82 		return -ENOMEM;
83 	ln->line = line;
84 	INIT_LIST_HEAD(&ln->list);
85 	list_add(&ln->list, p);
86 	return 0;
87 }
88 
89 /* Check if the line in line number list */
90 static int line_list__has_line(struct list_head *head, int line)
91 {
92 	struct line_node *ln;
93 
94 	/* Reverse search, because new line will be the last one */
95 	list_for_each_entry(ln, head, list)
96 		if (ln->line == line)
97 			return 1;
98 
99 	return 0;
100 }
101 
102 /* Init line number list */
103 static void line_list__init(struct list_head *head)
104 {
105 	INIT_LIST_HEAD(head);
106 }
107 
108 /* Free line number list */
109 static void line_list__free(struct list_head *head)
110 {
111 	struct line_node *ln;
112 	while (!list_empty(head)) {
113 		ln = list_first_entry(head, struct line_node, list);
114 		list_del(&ln->list);
115 		free(ln);
116 	}
117 }
118 
119 /* Dwarf FL wrappers */
120 static char *debuginfo_path;	/* Currently dummy */
121 
122 static const Dwfl_Callbacks offline_callbacks = {
123 	.find_debuginfo = dwfl_standard_find_debuginfo,
124 	.debuginfo_path = &debuginfo_path,
125 
126 	.section_address = dwfl_offline_section_address,
127 
128 	/* We use this table for core files too.  */
129 	.find_elf = dwfl_build_id_find_elf,
130 };
131 
132 /* Get a Dwarf from offline image */
133 static Dwarf *dwfl_init_offline_dwarf(int fd, Dwfl **dwflp, Dwarf_Addr *bias)
134 {
135 	Dwfl_Module *mod;
136 	Dwarf *dbg = NULL;
137 
138 	if (!dwflp)
139 		return NULL;
140 
141 	*dwflp = dwfl_begin(&offline_callbacks);
142 	if (!*dwflp)
143 		return NULL;
144 
145 	mod = dwfl_report_offline(*dwflp, "", "", fd);
146 	if (!mod)
147 		goto error;
148 
149 	dbg = dwfl_module_getdwarf(mod, bias);
150 	if (!dbg) {
151 error:
152 		dwfl_end(*dwflp);
153 		*dwflp = NULL;
154 	}
155 	return dbg;
156 }
157 
158 #if _ELFUTILS_PREREQ(0, 148)
159 /* This method is buggy if elfutils is older than 0.148 */
160 static int __linux_kernel_find_elf(Dwfl_Module *mod,
161 				   void **userdata,
162 				   const char *module_name,
163 				   Dwarf_Addr base,
164 				   char **file_name, Elf **elfp)
165 {
166 	int fd;
167 	const char *path = kernel_get_module_path(module_name);
168 
169 	pr_debug2("Use file %s for %s\n", path, module_name);
170 	if (path) {
171 		fd = open(path, O_RDONLY);
172 		if (fd >= 0) {
173 			*file_name = strdup(path);
174 			return fd;
175 		}
176 	}
177 	/* If failed, try to call standard method */
178 	return dwfl_linux_kernel_find_elf(mod, userdata, module_name, base,
179 					  file_name, elfp);
180 }
181 
182 static const Dwfl_Callbacks kernel_callbacks = {
183 	.find_debuginfo = dwfl_standard_find_debuginfo,
184 	.debuginfo_path = &debuginfo_path,
185 
186 	.find_elf = __linux_kernel_find_elf,
187 	.section_address = dwfl_linux_kernel_module_section_address,
188 };
189 
190 /* Get a Dwarf from live kernel image */
191 static Dwarf *dwfl_init_live_kernel_dwarf(Dwarf_Addr addr, Dwfl **dwflp,
192 					  Dwarf_Addr *bias)
193 {
194 	Dwarf *dbg;
195 
196 	if (!dwflp)
197 		return NULL;
198 
199 	*dwflp = dwfl_begin(&kernel_callbacks);
200 	if (!*dwflp)
201 		return NULL;
202 
203 	/* Load the kernel dwarves: Don't care the result here */
204 	dwfl_linux_kernel_report_kernel(*dwflp);
205 	dwfl_linux_kernel_report_modules(*dwflp);
206 
207 	dbg = dwfl_addrdwarf(*dwflp, addr, bias);
208 	/* Here, check whether we could get a real dwarf */
209 	if (!dbg) {
210 		pr_debug("Failed to find kernel dwarf at %lx\n",
211 			 (unsigned long)addr);
212 		dwfl_end(*dwflp);
213 		*dwflp = NULL;
214 	}
215 	return dbg;
216 }
217 #else
218 /* With older elfutils, this just support kernel module... */
219 static Dwarf *dwfl_init_live_kernel_dwarf(Dwarf_Addr addr __used, Dwfl **dwflp,
220 					  Dwarf_Addr *bias)
221 {
222 	int fd;
223 	const char *path = kernel_get_module_path("kernel");
224 
225 	if (!path) {
226 		pr_err("Failed to find vmlinux path\n");
227 		return NULL;
228 	}
229 
230 	pr_debug2("Use file %s for debuginfo\n", path);
231 	fd = open(path, O_RDONLY);
232 	if (fd < 0)
233 		return NULL;
234 
235 	return dwfl_init_offline_dwarf(fd, dwflp, bias);
236 }
237 #endif
238 
239 /* Dwarf wrappers */
240 
241 /* Find the realpath of the target file. */
242 static const char *cu_find_realpath(Dwarf_Die *cu_die, const char *fname)
243 {
244 	Dwarf_Files *files;
245 	size_t nfiles, i;
246 	const char *src = NULL;
247 	int ret;
248 
249 	if (!fname)
250 		return NULL;
251 
252 	ret = dwarf_getsrcfiles(cu_die, &files, &nfiles);
253 	if (ret != 0)
254 		return NULL;
255 
256 	for (i = 0; i < nfiles; i++) {
257 		src = dwarf_filesrc(files, i, NULL, NULL);
258 		if (strtailcmp(src, fname) == 0)
259 			break;
260 	}
261 	if (i == nfiles)
262 		return NULL;
263 	return src;
264 }
265 
266 /* Get DW_AT_comp_dir (should be NULL with older gcc) */
267 static const char *cu_get_comp_dir(Dwarf_Die *cu_die)
268 {
269 	Dwarf_Attribute attr;
270 	if (dwarf_attr(cu_die, DW_AT_comp_dir, &attr) == NULL)
271 		return NULL;
272 	return dwarf_formstring(&attr);
273 }
274 
275 /* Compare diename and tname */
276 static bool die_compare_name(Dwarf_Die *dw_die, const char *tname)
277 {
278 	const char *name;
279 	name = dwarf_diename(dw_die);
280 	return name ? (strcmp(tname, name) == 0) : false;
281 }
282 
283 /* Get type die */
284 static Dwarf_Die *die_get_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
285 {
286 	Dwarf_Attribute attr;
287 
288 	if (dwarf_attr_integrate(vr_die, DW_AT_type, &attr) &&
289 	    dwarf_formref_die(&attr, die_mem))
290 		return die_mem;
291 	else
292 		return NULL;
293 }
294 
295 /* Get a type die, but skip qualifiers */
296 static Dwarf_Die *__die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
297 {
298 	int tag;
299 
300 	do {
301 		vr_die = die_get_type(vr_die, die_mem);
302 		if (!vr_die)
303 			break;
304 		tag = dwarf_tag(vr_die);
305 	} while (tag == DW_TAG_const_type ||
306 		 tag == DW_TAG_restrict_type ||
307 		 tag == DW_TAG_volatile_type ||
308 		 tag == DW_TAG_shared_type);
309 
310 	return vr_die;
311 }
312 
313 /* Get a type die, but skip qualifiers and typedef */
314 static Dwarf_Die *die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
315 {
316 	do {
317 		vr_die = __die_get_real_type(vr_die, die_mem);
318 	} while (vr_die && dwarf_tag(vr_die) == DW_TAG_typedef);
319 
320 	return vr_die;
321 }
322 
323 static bool die_is_signed_type(Dwarf_Die *tp_die)
324 {
325 	Dwarf_Attribute attr;
326 	Dwarf_Word ret;
327 
328 	if (dwarf_attr(tp_die, DW_AT_encoding, &attr) == NULL ||
329 	    dwarf_formudata(&attr, &ret) != 0)
330 		return false;
331 
332 	return (ret == DW_ATE_signed_char || ret == DW_ATE_signed ||
333 		ret == DW_ATE_signed_fixed);
334 }
335 
336 static int die_get_byte_size(Dwarf_Die *tp_die)
337 {
338 	Dwarf_Attribute attr;
339 	Dwarf_Word ret;
340 
341 	if (dwarf_attr(tp_die, DW_AT_byte_size, &attr) == NULL ||
342 	    dwarf_formudata(&attr, &ret) != 0)
343 		return 0;
344 
345 	return (int)ret;
346 }
347 
348 /* Get data_member_location offset */
349 static int die_get_data_member_location(Dwarf_Die *mb_die, Dwarf_Word *offs)
350 {
351 	Dwarf_Attribute attr;
352 	Dwarf_Op *expr;
353 	size_t nexpr;
354 	int ret;
355 
356 	if (dwarf_attr(mb_die, DW_AT_data_member_location, &attr) == NULL)
357 		return -ENOENT;
358 
359 	if (dwarf_formudata(&attr, offs) != 0) {
360 		/* DW_AT_data_member_location should be DW_OP_plus_uconst */
361 		ret = dwarf_getlocation(&attr, &expr, &nexpr);
362 		if (ret < 0 || nexpr == 0)
363 			return -ENOENT;
364 
365 		if (expr[0].atom != DW_OP_plus_uconst || nexpr != 1) {
366 			pr_debug("Unable to get offset:Unexpected OP %x (%zd)\n",
367 				 expr[0].atom, nexpr);
368 			return -ENOTSUP;
369 		}
370 		*offs = (Dwarf_Word)expr[0].number;
371 	}
372 	return 0;
373 }
374 
375 /* Return values for die_find callbacks */
376 enum {
377 	DIE_FIND_CB_FOUND = 0,		/* End of Search */
378 	DIE_FIND_CB_CHILD = 1,		/* Search only children */
379 	DIE_FIND_CB_SIBLING = 2,	/* Search only siblings */
380 	DIE_FIND_CB_CONTINUE = 3,	/* Search children and siblings */
381 };
382 
383 /* Search a child die */
384 static Dwarf_Die *die_find_child(Dwarf_Die *rt_die,
385 				 int (*callback)(Dwarf_Die *, void *),
386 				 void *data, Dwarf_Die *die_mem)
387 {
388 	Dwarf_Die child_die;
389 	int ret;
390 
391 	ret = dwarf_child(rt_die, die_mem);
392 	if (ret != 0)
393 		return NULL;
394 
395 	do {
396 		ret = callback(die_mem, data);
397 		if (ret == DIE_FIND_CB_FOUND)
398 			return die_mem;
399 
400 		if ((ret & DIE_FIND_CB_CHILD) &&
401 		    die_find_child(die_mem, callback, data, &child_die)) {
402 			memcpy(die_mem, &child_die, sizeof(Dwarf_Die));
403 			return die_mem;
404 		}
405 	} while ((ret & DIE_FIND_CB_SIBLING) &&
406 		 dwarf_siblingof(die_mem, die_mem) == 0);
407 
408 	return NULL;
409 }
410 
411 struct __addr_die_search_param {
412 	Dwarf_Addr	addr;
413 	Dwarf_Die	*die_mem;
414 };
415 
416 static int __die_search_func_cb(Dwarf_Die *fn_die, void *data)
417 {
418 	struct __addr_die_search_param *ad = data;
419 
420 	if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
421 	    dwarf_haspc(fn_die, ad->addr)) {
422 		memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
423 		return DWARF_CB_ABORT;
424 	}
425 	return DWARF_CB_OK;
426 }
427 
428 /* Search a real subprogram including this line, */
429 static Dwarf_Die *die_find_real_subprogram(Dwarf_Die *cu_die, Dwarf_Addr addr,
430 					   Dwarf_Die *die_mem)
431 {
432 	struct __addr_die_search_param ad;
433 	ad.addr = addr;
434 	ad.die_mem = die_mem;
435 	/* dwarf_getscopes can't find subprogram. */
436 	if (!dwarf_getfuncs(cu_die, __die_search_func_cb, &ad, 0))
437 		return NULL;
438 	else
439 		return die_mem;
440 }
441 
442 /* die_find callback for inline function search */
443 static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data)
444 {
445 	Dwarf_Addr *addr = data;
446 
447 	if (dwarf_tag(die_mem) == DW_TAG_inlined_subroutine &&
448 	    dwarf_haspc(die_mem, *addr))
449 		return DIE_FIND_CB_FOUND;
450 
451 	return DIE_FIND_CB_CONTINUE;
452 }
453 
454 /* Similar to dwarf_getfuncs, but returns inlined_subroutine if exists. */
455 static Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
456 				      Dwarf_Die *die_mem)
457 {
458 	return die_find_child(sp_die, __die_find_inline_cb, &addr, die_mem);
459 }
460 
461 struct __find_variable_param {
462 	const char *name;
463 	Dwarf_Addr addr;
464 };
465 
466 static int __die_find_variable_cb(Dwarf_Die *die_mem, void *data)
467 {
468 	struct __find_variable_param *fvp = data;
469 	int tag;
470 
471 	tag = dwarf_tag(die_mem);
472 	if ((tag == DW_TAG_formal_parameter ||
473 	     tag == DW_TAG_variable) &&
474 	    die_compare_name(die_mem, fvp->name))
475 		return DIE_FIND_CB_FOUND;
476 
477 	if (dwarf_haspc(die_mem, fvp->addr))
478 		return DIE_FIND_CB_CONTINUE;
479 	else
480 		return DIE_FIND_CB_SIBLING;
481 }
482 
483 /* Find a variable called 'name' at given address */
484 static Dwarf_Die *die_find_variable_at(Dwarf_Die *sp_die, const char *name,
485 				       Dwarf_Addr addr, Dwarf_Die *die_mem)
486 {
487 	struct __find_variable_param fvp = { .name = name, .addr = addr};
488 
489 	return die_find_child(sp_die, __die_find_variable_cb, (void *)&fvp,
490 			      die_mem);
491 }
492 
493 static int __die_find_member_cb(Dwarf_Die *die_mem, void *data)
494 {
495 	const char *name = data;
496 
497 	if ((dwarf_tag(die_mem) == DW_TAG_member) &&
498 	    die_compare_name(die_mem, name))
499 		return DIE_FIND_CB_FOUND;
500 
501 	return DIE_FIND_CB_SIBLING;
502 }
503 
504 /* Find a member called 'name' */
505 static Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name,
506 				  Dwarf_Die *die_mem)
507 {
508 	return die_find_child(st_die, __die_find_member_cb, (void *)name,
509 			      die_mem);
510 }
511 
512 /* Get the name of given variable DIE */
513 static int die_get_typename(Dwarf_Die *vr_die, char *buf, int len)
514 {
515 	Dwarf_Die type;
516 	int tag, ret, ret2;
517 	const char *tmp = "";
518 
519 	if (__die_get_real_type(vr_die, &type) == NULL)
520 		return -ENOENT;
521 
522 	tag = dwarf_tag(&type);
523 	if (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)
524 		tmp = "*";
525 	else if (tag == DW_TAG_subroutine_type) {
526 		/* Function pointer */
527 		ret = snprintf(buf, len, "(function_type)");
528 		return (ret >= len) ? -E2BIG : ret;
529 	} else {
530 		if (!dwarf_diename(&type))
531 			return -ENOENT;
532 		if (tag == DW_TAG_union_type)
533 			tmp = "union ";
534 		else if (tag == DW_TAG_structure_type)
535 			tmp = "struct ";
536 		/* Write a base name */
537 		ret = snprintf(buf, len, "%s%s", tmp, dwarf_diename(&type));
538 		return (ret >= len) ? -E2BIG : ret;
539 	}
540 	ret = die_get_typename(&type, buf, len);
541 	if (ret > 0) {
542 		ret2 = snprintf(buf + ret, len - ret, "%s", tmp);
543 		ret = (ret2 >= len - ret) ? -E2BIG : ret2 + ret;
544 	}
545 	return ret;
546 }
547 
548 /* Get the name and type of given variable DIE, stored as "type\tname" */
549 static int die_get_varname(Dwarf_Die *vr_die, char *buf, int len)
550 {
551 	int ret, ret2;
552 
553 	ret = die_get_typename(vr_die, buf, len);
554 	if (ret < 0) {
555 		pr_debug("Failed to get type, make it unknown.\n");
556 		ret = snprintf(buf, len, "(unknown_type)");
557 	}
558 	if (ret > 0) {
559 		ret2 = snprintf(buf + ret, len - ret, "\t%s",
560 				dwarf_diename(vr_die));
561 		ret = (ret2 >= len - ret) ? -E2BIG : ret2 + ret;
562 	}
563 	return ret;
564 }
565 
566 /*
567  * Probe finder related functions
568  */
569 
570 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
571 {
572 	struct probe_trace_arg_ref *ref;
573 	ref = zalloc(sizeof(struct probe_trace_arg_ref));
574 	if (ref != NULL)
575 		ref->offset = offs;
576 	return ref;
577 }
578 
579 /*
580  * Convert a location into trace_arg.
581  * If tvar == NULL, this just checks variable can be converted.
582  */
583 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
584 				     Dwarf_Op *fb_ops,
585 				     struct probe_trace_arg *tvar)
586 {
587 	Dwarf_Attribute attr;
588 	Dwarf_Op *op;
589 	size_t nops;
590 	unsigned int regn;
591 	Dwarf_Word offs = 0;
592 	bool ref = false;
593 	const char *regs;
594 	int ret;
595 
596 	if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
597 		goto static_var;
598 
599 	/* TODO: handle more than 1 exprs */
600 	if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL ||
601 	    dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0 ||
602 	    nops == 0) {
603 		/* TODO: Support const_value */
604 		return -ENOENT;
605 	}
606 
607 	if (op->atom == DW_OP_addr) {
608 static_var:
609 		if (!tvar)
610 			return 0;
611 		/* Static variables on memory (not stack), make @varname */
612 		ret = strlen(dwarf_diename(vr_die));
613 		tvar->value = zalloc(ret + 2);
614 		if (tvar->value == NULL)
615 			return -ENOMEM;
616 		snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
617 		tvar->ref = alloc_trace_arg_ref((long)offs);
618 		if (tvar->ref == NULL)
619 			return -ENOMEM;
620 		return 0;
621 	}
622 
623 	/* If this is based on frame buffer, set the offset */
624 	if (op->atom == DW_OP_fbreg) {
625 		if (fb_ops == NULL)
626 			return -ENOTSUP;
627 		ref = true;
628 		offs = op->number;
629 		op = &fb_ops[0];
630 	}
631 
632 	if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
633 		regn = op->atom - DW_OP_breg0;
634 		offs += op->number;
635 		ref = true;
636 	} else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
637 		regn = op->atom - DW_OP_reg0;
638 	} else if (op->atom == DW_OP_bregx) {
639 		regn = op->number;
640 		offs += op->number2;
641 		ref = true;
642 	} else if (op->atom == DW_OP_regx) {
643 		regn = op->number;
644 	} else {
645 		pr_debug("DW_OP %x is not supported.\n", op->atom);
646 		return -ENOTSUP;
647 	}
648 
649 	if (!tvar)
650 		return 0;
651 
652 	regs = get_arch_regstr(regn);
653 	if (!regs) {
654 		/* This should be a bug in DWARF or this tool */
655 		pr_warning("Mapping for the register number %u "
656 			   "missing on this architecture.\n", regn);
657 		return -ERANGE;
658 	}
659 
660 	tvar->value = strdup(regs);
661 	if (tvar->value == NULL)
662 		return -ENOMEM;
663 
664 	if (ref) {
665 		tvar->ref = alloc_trace_arg_ref((long)offs);
666 		if (tvar->ref == NULL)
667 			return -ENOMEM;
668 	}
669 	return 0;
670 }
671 
672 static int convert_variable_type(Dwarf_Die *vr_die,
673 				 struct probe_trace_arg *tvar,
674 				 const char *cast)
675 {
676 	struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
677 	Dwarf_Die type;
678 	char buf[16];
679 	int ret;
680 
681 	/* TODO: check all types */
682 	if (cast && strcmp(cast, "string") != 0) {
683 		/* Non string type is OK */
684 		tvar->type = strdup(cast);
685 		return (tvar->type == NULL) ? -ENOMEM : 0;
686 	}
687 
688 	if (die_get_real_type(vr_die, &type) == NULL) {
689 		pr_warning("Failed to get a type information of %s.\n",
690 			   dwarf_diename(vr_die));
691 		return -ENOENT;
692 	}
693 
694 	pr_debug("%s type is %s.\n",
695 		 dwarf_diename(vr_die), dwarf_diename(&type));
696 
697 	if (cast && strcmp(cast, "string") == 0) {	/* String type */
698 		ret = dwarf_tag(&type);
699 		if (ret != DW_TAG_pointer_type &&
700 		    ret != DW_TAG_array_type) {
701 			pr_warning("Failed to cast into string: "
702 				   "%s(%s) is not a pointer nor array.\n",
703 				   dwarf_diename(vr_die), dwarf_diename(&type));
704 			return -EINVAL;
705 		}
706 		if (ret == DW_TAG_pointer_type) {
707 			if (die_get_real_type(&type, &type) == NULL) {
708 				pr_warning("Failed to get a type"
709 					   " information.\n");
710 				return -ENOENT;
711 			}
712 			while (*ref_ptr)
713 				ref_ptr = &(*ref_ptr)->next;
714 			/* Add new reference with offset +0 */
715 			*ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
716 			if (*ref_ptr == NULL) {
717 				pr_warning("Out of memory error\n");
718 				return -ENOMEM;
719 			}
720 		}
721 		if (!die_compare_name(&type, "char") &&
722 		    !die_compare_name(&type, "unsigned char")) {
723 			pr_warning("Failed to cast into string: "
724 				   "%s is not (unsigned) char *.\n",
725 				   dwarf_diename(vr_die));
726 			return -EINVAL;
727 		}
728 		tvar->type = strdup(cast);
729 		return (tvar->type == NULL) ? -ENOMEM : 0;
730 	}
731 
732 	ret = die_get_byte_size(&type) * 8;
733 	if (ret) {
734 		/* Check the bitwidth */
735 		if (ret > MAX_BASIC_TYPE_BITS) {
736 			pr_info("%s exceeds max-bitwidth."
737 				" Cut down to %d bits.\n",
738 				dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
739 			ret = MAX_BASIC_TYPE_BITS;
740 		}
741 
742 		ret = snprintf(buf, 16, "%c%d",
743 			       die_is_signed_type(&type) ? 's' : 'u', ret);
744 		if (ret < 0 || ret >= 16) {
745 			if (ret >= 16)
746 				ret = -E2BIG;
747 			pr_warning("Failed to convert variable type: %s\n",
748 				   strerror(-ret));
749 			return ret;
750 		}
751 		tvar->type = strdup(buf);
752 		if (tvar->type == NULL)
753 			return -ENOMEM;
754 	}
755 	return 0;
756 }
757 
758 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
759 				    struct perf_probe_arg_field *field,
760 				    struct probe_trace_arg_ref **ref_ptr,
761 				    Dwarf_Die *die_mem)
762 {
763 	struct probe_trace_arg_ref *ref = *ref_ptr;
764 	Dwarf_Die type;
765 	Dwarf_Word offs;
766 	int ret, tag;
767 
768 	pr_debug("converting %s in %s\n", field->name, varname);
769 	if (die_get_real_type(vr_die, &type) == NULL) {
770 		pr_warning("Failed to get the type of %s.\n", varname);
771 		return -ENOENT;
772 	}
773 	pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
774 	tag = dwarf_tag(&type);
775 
776 	if (field->name[0] == '[' &&
777 	    (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
778 		if (field->next)
779 			/* Save original type for next field */
780 			memcpy(die_mem, &type, sizeof(*die_mem));
781 		/* Get the type of this array */
782 		if (die_get_real_type(&type, &type) == NULL) {
783 			pr_warning("Failed to get the type of %s.\n", varname);
784 			return -ENOENT;
785 		}
786 		pr_debug2("Array real type: (%x)\n",
787 			 (unsigned)dwarf_dieoffset(&type));
788 		if (tag == DW_TAG_pointer_type) {
789 			ref = zalloc(sizeof(struct probe_trace_arg_ref));
790 			if (ref == NULL)
791 				return -ENOMEM;
792 			if (*ref_ptr)
793 				(*ref_ptr)->next = ref;
794 			else
795 				*ref_ptr = ref;
796 		}
797 		ref->offset += die_get_byte_size(&type) * field->index;
798 		if (!field->next)
799 			/* Save vr_die for converting types */
800 			memcpy(die_mem, vr_die, sizeof(*die_mem));
801 		goto next;
802 	} else if (tag == DW_TAG_pointer_type) {
803 		/* Check the pointer and dereference */
804 		if (!field->ref) {
805 			pr_err("Semantic error: %s must be referred by '->'\n",
806 			       field->name);
807 			return -EINVAL;
808 		}
809 		/* Get the type pointed by this pointer */
810 		if (die_get_real_type(&type, &type) == NULL) {
811 			pr_warning("Failed to get the type of %s.\n", varname);
812 			return -ENOENT;
813 		}
814 		/* Verify it is a data structure  */
815 		if (dwarf_tag(&type) != DW_TAG_structure_type) {
816 			pr_warning("%s is not a data structure.\n", varname);
817 			return -EINVAL;
818 		}
819 
820 		ref = zalloc(sizeof(struct probe_trace_arg_ref));
821 		if (ref == NULL)
822 			return -ENOMEM;
823 		if (*ref_ptr)
824 			(*ref_ptr)->next = ref;
825 		else
826 			*ref_ptr = ref;
827 	} else {
828 		/* Verify it is a data structure  */
829 		if (tag != DW_TAG_structure_type) {
830 			pr_warning("%s is not a data structure.\n", varname);
831 			return -EINVAL;
832 		}
833 		if (field->name[0] == '[') {
834 			pr_err("Semantic error: %s is not a pointor"
835 			       " nor array.\n", varname);
836 			return -EINVAL;
837 		}
838 		if (field->ref) {
839 			pr_err("Semantic error: %s must be referred by '.'\n",
840 			       field->name);
841 			return -EINVAL;
842 		}
843 		if (!ref) {
844 			pr_warning("Structure on a register is not "
845 				   "supported yet.\n");
846 			return -ENOTSUP;
847 		}
848 	}
849 
850 	if (die_find_member(&type, field->name, die_mem) == NULL) {
851 		pr_warning("%s(tyep:%s) has no member %s.\n", varname,
852 			   dwarf_diename(&type), field->name);
853 		return -EINVAL;
854 	}
855 
856 	/* Get the offset of the field */
857 	ret = die_get_data_member_location(die_mem, &offs);
858 	if (ret < 0) {
859 		pr_warning("Failed to get the offset of %s.\n", field->name);
860 		return ret;
861 	}
862 	ref->offset += (long)offs;
863 
864 next:
865 	/* Converting next field */
866 	if (field->next)
867 		return convert_variable_fields(die_mem, field->name,
868 					field->next, &ref, die_mem);
869 	else
870 		return 0;
871 }
872 
873 /* Show a variables in kprobe event format */
874 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
875 {
876 	Dwarf_Die die_mem;
877 	int ret;
878 
879 	pr_debug("Converting variable %s into trace event.\n",
880 		 dwarf_diename(vr_die));
881 
882 	ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
883 					pf->tvar);
884 	if (ret == -ENOENT)
885 		pr_err("Failed to find the location of %s at this address.\n"
886 		       " Perhaps, it has been optimized out.\n", pf->pvar->var);
887 	else if (ret == -ENOTSUP)
888 		pr_err("Sorry, we don't support this variable location yet.\n");
889 	else if (pf->pvar->field) {
890 		ret = convert_variable_fields(vr_die, pf->pvar->var,
891 					      pf->pvar->field, &pf->tvar->ref,
892 					      &die_mem);
893 		vr_die = &die_mem;
894 	}
895 	if (ret == 0)
896 		ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
897 	/* *expr will be cached in libdw. Don't free it. */
898 	return ret;
899 }
900 
901 /* Find a variable in a subprogram die */
902 static int find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
903 {
904 	Dwarf_Die vr_die, *scopes;
905 	char buf[32], *ptr;
906 	int ret, nscopes;
907 
908 	if (!is_c_varname(pf->pvar->var)) {
909 		/* Copy raw parameters */
910 		pf->tvar->value = strdup(pf->pvar->var);
911 		if (pf->tvar->value == NULL)
912 			return -ENOMEM;
913 		if (pf->pvar->type) {
914 			pf->tvar->type = strdup(pf->pvar->type);
915 			if (pf->tvar->type == NULL)
916 				return -ENOMEM;
917 		}
918 		if (pf->pvar->name) {
919 			pf->tvar->name = strdup(pf->pvar->name);
920 			if (pf->tvar->name == NULL)
921 				return -ENOMEM;
922 		} else
923 			pf->tvar->name = NULL;
924 		return 0;
925 	}
926 
927 	if (pf->pvar->name)
928 		pf->tvar->name = strdup(pf->pvar->name);
929 	else {
930 		ret = synthesize_perf_probe_arg(pf->pvar, buf, 32);
931 		if (ret < 0)
932 			return ret;
933 		ptr = strchr(buf, ':');	/* Change type separator to _ */
934 		if (ptr)
935 			*ptr = '_';
936 		pf->tvar->name = strdup(buf);
937 	}
938 	if (pf->tvar->name == NULL)
939 		return -ENOMEM;
940 
941 	pr_debug("Searching '%s' variable in context.\n",
942 		 pf->pvar->var);
943 	/* Search child die for local variables and parameters. */
944 	if (die_find_variable_at(sp_die, pf->pvar->var, pf->addr, &vr_die))
945 		ret = convert_variable(&vr_die, pf);
946 	else {
947 		/* Search upper class */
948 		nscopes = dwarf_getscopes_die(sp_die, &scopes);
949 		while (nscopes-- > 1) {
950 			pr_debug("Searching variables in %s\n",
951 				 dwarf_diename(&scopes[nscopes]));
952 			/* We should check this scope, so give dummy address */
953 			if (die_find_variable_at(&scopes[nscopes],
954 						 pf->pvar->var, 0,
955 						 &vr_die)) {
956 				ret = convert_variable(&vr_die, pf);
957 				goto found;
958 			}
959 		}
960 		if (scopes)
961 			free(scopes);
962 		ret = -ENOENT;
963 	}
964 found:
965 	if (ret < 0)
966 		pr_warning("Failed to find '%s' in this function.\n",
967 			   pf->pvar->var);
968 	return ret;
969 }
970 
971 /* Convert subprogram DIE to trace point */
972 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwarf_Addr paddr,
973 				  bool retprobe, struct probe_trace_point *tp)
974 {
975 	Dwarf_Addr eaddr;
976 	const char *name;
977 
978 	/* Copy the name of probe point */
979 	name = dwarf_diename(sp_die);
980 	if (name) {
981 		if (dwarf_entrypc(sp_die, &eaddr) != 0) {
982 			pr_warning("Failed to get entry address of %s\n",
983 				   dwarf_diename(sp_die));
984 			return -ENOENT;
985 		}
986 		tp->symbol = strdup(name);
987 		if (tp->symbol == NULL)
988 			return -ENOMEM;
989 		tp->offset = (unsigned long)(paddr - eaddr);
990 	} else
991 		/* This function has no name. */
992 		tp->offset = (unsigned long)paddr;
993 
994 	/* Return probe must be on the head of a subprogram */
995 	if (retprobe) {
996 		if (eaddr != paddr) {
997 			pr_warning("Return probe must be on the head of"
998 				   " a real function.\n");
999 			return -EINVAL;
1000 		}
1001 		tp->retprobe = true;
1002 	}
1003 
1004 	return 0;
1005 }
1006 
1007 /* Call probe_finder callback with real subprogram DIE */
1008 static int call_probe_finder(Dwarf_Die *sp_die, struct probe_finder *pf)
1009 {
1010 	Dwarf_Die die_mem;
1011 	Dwarf_Attribute fb_attr;
1012 	size_t nops;
1013 	int ret;
1014 
1015 	/* If no real subprogram, find a real one */
1016 	if (!sp_die || dwarf_tag(sp_die) != DW_TAG_subprogram) {
1017 		sp_die = die_find_real_subprogram(&pf->cu_die,
1018 						  pf->addr, &die_mem);
1019 		if (!sp_die) {
1020 			pr_warning("Failed to find probe point in any "
1021 				   "functions.\n");
1022 			return -ENOENT;
1023 		}
1024 	}
1025 
1026 	/* Get the frame base attribute/ops */
1027 	dwarf_attr(sp_die, DW_AT_frame_base, &fb_attr);
1028 	ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
1029 	if (ret <= 0 || nops == 0) {
1030 		pf->fb_ops = NULL;
1031 #if _ELFUTILS_PREREQ(0, 142)
1032 	} else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
1033 		   pf->cfi != NULL) {
1034 		Dwarf_Frame *frame;
1035 		if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
1036 		    dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
1037 			pr_warning("Failed to get call frame on 0x%jx\n",
1038 				   (uintmax_t)pf->addr);
1039 			return -ENOENT;
1040 		}
1041 #endif
1042 	}
1043 
1044 	/* Call finder's callback handler */
1045 	ret = pf->callback(sp_die, pf);
1046 
1047 	/* *pf->fb_ops will be cached in libdw. Don't free it. */
1048 	pf->fb_ops = NULL;
1049 
1050 	return ret;
1051 }
1052 
1053 /* Find probe point from its line number */
1054 static int find_probe_point_by_line(struct probe_finder *pf)
1055 {
1056 	Dwarf_Lines *lines;
1057 	Dwarf_Line *line;
1058 	size_t nlines, i;
1059 	Dwarf_Addr addr;
1060 	int lineno;
1061 	int ret = 0;
1062 
1063 	if (dwarf_getsrclines(&pf->cu_die, &lines, &nlines) != 0) {
1064 		pr_warning("No source lines found.\n");
1065 		return -ENOENT;
1066 	}
1067 
1068 	for (i = 0; i < nlines && ret == 0; i++) {
1069 		line = dwarf_onesrcline(lines, i);
1070 		if (dwarf_lineno(line, &lineno) != 0 ||
1071 		    lineno != pf->lno)
1072 			continue;
1073 
1074 		/* TODO: Get fileno from line, but how? */
1075 		if (strtailcmp(dwarf_linesrc(line, NULL, NULL), pf->fname) != 0)
1076 			continue;
1077 
1078 		if (dwarf_lineaddr(line, &addr) != 0) {
1079 			pr_warning("Failed to get the address of the line.\n");
1080 			return -ENOENT;
1081 		}
1082 		pr_debug("Probe line found: line[%d]:%d addr:0x%jx\n",
1083 			 (int)i, lineno, (uintmax_t)addr);
1084 		pf->addr = addr;
1085 
1086 		ret = call_probe_finder(NULL, pf);
1087 		/* Continuing, because target line might be inlined. */
1088 	}
1089 	return ret;
1090 }
1091 
1092 /* Find lines which match lazy pattern */
1093 static int find_lazy_match_lines(struct list_head *head,
1094 				 const char *fname, const char *pat)
1095 {
1096 	char *fbuf, *p1, *p2;
1097 	int fd, line, nlines = -1;
1098 	struct stat st;
1099 
1100 	fd = open(fname, O_RDONLY);
1101 	if (fd < 0) {
1102 		pr_warning("Failed to open %s: %s\n", fname, strerror(-fd));
1103 		return -errno;
1104 	}
1105 
1106 	if (fstat(fd, &st) < 0) {
1107 		pr_warning("Failed to get the size of %s: %s\n",
1108 			   fname, strerror(errno));
1109 		nlines = -errno;
1110 		goto out_close;
1111 	}
1112 
1113 	nlines = -ENOMEM;
1114 	fbuf = malloc(st.st_size + 2);
1115 	if (fbuf == NULL)
1116 		goto out_close;
1117 	if (read(fd, fbuf, st.st_size) < 0) {
1118 		pr_warning("Failed to read %s: %s\n", fname, strerror(errno));
1119 		nlines = -errno;
1120 		goto out_free_fbuf;
1121 	}
1122 	fbuf[st.st_size] = '\n';	/* Dummy line */
1123 	fbuf[st.st_size + 1] = '\0';
1124 	p1 = fbuf;
1125 	line = 1;
1126 	nlines = 0;
1127 	while ((p2 = strchr(p1, '\n')) != NULL) {
1128 		*p2 = '\0';
1129 		if (strlazymatch(p1, pat)) {
1130 			line_list__add_line(head, line);
1131 			nlines++;
1132 		}
1133 		line++;
1134 		p1 = p2 + 1;
1135 	}
1136 out_free_fbuf:
1137 	free(fbuf);
1138 out_close:
1139 	close(fd);
1140 	return nlines;
1141 }
1142 
1143 /* Find probe points from lazy pattern  */
1144 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
1145 {
1146 	Dwarf_Lines *lines;
1147 	Dwarf_Line *line;
1148 	size_t nlines, i;
1149 	Dwarf_Addr addr;
1150 	Dwarf_Die die_mem;
1151 	int lineno;
1152 	int ret = 0;
1153 
1154 	if (list_empty(&pf->lcache)) {
1155 		/* Matching lazy line pattern */
1156 		ret = find_lazy_match_lines(&pf->lcache, pf->fname,
1157 					    pf->pev->point.lazy_line);
1158 		if (ret == 0) {
1159 			pr_debug("No matched lines found in %s.\n", pf->fname);
1160 			return 0;
1161 		} else if (ret < 0)
1162 			return ret;
1163 	}
1164 
1165 	if (dwarf_getsrclines(&pf->cu_die, &lines, &nlines) != 0) {
1166 		pr_warning("No source lines found.\n");
1167 		return -ENOENT;
1168 	}
1169 
1170 	for (i = 0; i < nlines && ret >= 0; i++) {
1171 		line = dwarf_onesrcline(lines, i);
1172 
1173 		if (dwarf_lineno(line, &lineno) != 0 ||
1174 		    !line_list__has_line(&pf->lcache, lineno))
1175 			continue;
1176 
1177 		/* TODO: Get fileno from line, but how? */
1178 		if (strtailcmp(dwarf_linesrc(line, NULL, NULL), pf->fname) != 0)
1179 			continue;
1180 
1181 		if (dwarf_lineaddr(line, &addr) != 0) {
1182 			pr_debug("Failed to get the address of line %d.\n",
1183 				 lineno);
1184 			continue;
1185 		}
1186 		if (sp_die) {
1187 			/* Address filtering 1: does sp_die include addr? */
1188 			if (!dwarf_haspc(sp_die, addr))
1189 				continue;
1190 			/* Address filtering 2: No child include addr? */
1191 			if (die_find_inlinefunc(sp_die, addr, &die_mem))
1192 				continue;
1193 		}
1194 
1195 		pr_debug("Probe line found: line[%d]:%d addr:0x%llx\n",
1196 			 (int)i, lineno, (unsigned long long)addr);
1197 		pf->addr = addr;
1198 
1199 		ret = call_probe_finder(sp_die, pf);
1200 		/* Continuing, because target line might be inlined. */
1201 	}
1202 	/* TODO: deallocate lines, but how? */
1203 	return ret;
1204 }
1205 
1206 /* Callback parameter with return value */
1207 struct dwarf_callback_param {
1208 	void *data;
1209 	int retval;
1210 };
1211 
1212 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
1213 {
1214 	struct dwarf_callback_param *param = data;
1215 	struct probe_finder *pf = param->data;
1216 	struct perf_probe_point *pp = &pf->pev->point;
1217 	Dwarf_Addr addr;
1218 
1219 	if (pp->lazy_line)
1220 		param->retval = find_probe_point_lazy(in_die, pf);
1221 	else {
1222 		/* Get probe address */
1223 		if (dwarf_entrypc(in_die, &addr) != 0) {
1224 			pr_warning("Failed to get entry address of %s.\n",
1225 				   dwarf_diename(in_die));
1226 			param->retval = -ENOENT;
1227 			return DWARF_CB_ABORT;
1228 		}
1229 		pf->addr = addr;
1230 		pf->addr += pp->offset;
1231 		pr_debug("found inline addr: 0x%jx\n",
1232 			 (uintmax_t)pf->addr);
1233 
1234 		param->retval = call_probe_finder(in_die, pf);
1235 		if (param->retval < 0)
1236 			return DWARF_CB_ABORT;
1237 	}
1238 
1239 	return DWARF_CB_OK;
1240 }
1241 
1242 /* Search function from function name */
1243 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
1244 {
1245 	struct dwarf_callback_param *param = data;
1246 	struct probe_finder *pf = param->data;
1247 	struct perf_probe_point *pp = &pf->pev->point;
1248 
1249 	/* Check tag and diename */
1250 	if (dwarf_tag(sp_die) != DW_TAG_subprogram ||
1251 	    !die_compare_name(sp_die, pp->function))
1252 		return DWARF_CB_OK;
1253 
1254 	pf->fname = dwarf_decl_file(sp_die);
1255 	if (pp->line) { /* Function relative line */
1256 		dwarf_decl_line(sp_die, &pf->lno);
1257 		pf->lno += pp->line;
1258 		param->retval = find_probe_point_by_line(pf);
1259 	} else if (!dwarf_func_inline(sp_die)) {
1260 		/* Real function */
1261 		if (pp->lazy_line)
1262 			param->retval = find_probe_point_lazy(sp_die, pf);
1263 		else {
1264 			if (dwarf_entrypc(sp_die, &pf->addr) != 0) {
1265 				pr_warning("Failed to get entry address of "
1266 					   "%s.\n", dwarf_diename(sp_die));
1267 				param->retval = -ENOENT;
1268 				return DWARF_CB_ABORT;
1269 			}
1270 			pf->addr += pp->offset;
1271 			/* TODO: Check the address in this function */
1272 			param->retval = call_probe_finder(sp_die, pf);
1273 		}
1274 	} else {
1275 		struct dwarf_callback_param _param = {.data = (void *)pf,
1276 						      .retval = 0};
1277 		/* Inlined function: search instances */
1278 		dwarf_func_inline_instances(sp_die, probe_point_inline_cb,
1279 					    &_param);
1280 		param->retval = _param.retval;
1281 	}
1282 
1283 	return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1284 }
1285 
1286 static int find_probe_point_by_func(struct probe_finder *pf)
1287 {
1288 	struct dwarf_callback_param _param = {.data = (void *)pf,
1289 					      .retval = 0};
1290 	dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1291 	return _param.retval;
1292 }
1293 
1294 /* Find probe points from debuginfo */
1295 static int find_probes(int fd, struct probe_finder *pf)
1296 {
1297 	struct perf_probe_point *pp = &pf->pev->point;
1298 	Dwarf_Off off, noff;
1299 	size_t cuhl;
1300 	Dwarf_Die *diep;
1301 	Dwarf *dbg = NULL;
1302 	Dwfl *dwfl;
1303 	Dwarf_Addr bias;	/* Currently ignored */
1304 	int ret = 0;
1305 
1306 	dbg = dwfl_init_offline_dwarf(fd, &dwfl, &bias);
1307 	if (!dbg) {
1308 		pr_warning("No debug information found in the vmlinux - "
1309 			"please rebuild with CONFIG_DEBUG_INFO=y.\n");
1310 		return -EBADF;
1311 	}
1312 
1313 #if _ELFUTILS_PREREQ(0, 142)
1314 	/* Get the call frame information from this dwarf */
1315 	pf->cfi = dwarf_getcfi(dbg);
1316 #endif
1317 
1318 	off = 0;
1319 	line_list__init(&pf->lcache);
1320 	/* Loop on CUs (Compilation Unit) */
1321 	while (!dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL) &&
1322 	       ret >= 0) {
1323 		/* Get the DIE(Debugging Information Entry) of this CU */
1324 		diep = dwarf_offdie(dbg, off + cuhl, &pf->cu_die);
1325 		if (!diep)
1326 			continue;
1327 
1328 		/* Check if target file is included. */
1329 		if (pp->file)
1330 			pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1331 		else
1332 			pf->fname = NULL;
1333 
1334 		if (!pp->file || pf->fname) {
1335 			if (pp->function)
1336 				ret = find_probe_point_by_func(pf);
1337 			else if (pp->lazy_line)
1338 				ret = find_probe_point_lazy(NULL, pf);
1339 			else {
1340 				pf->lno = pp->line;
1341 				ret = find_probe_point_by_line(pf);
1342 			}
1343 		}
1344 		off = noff;
1345 	}
1346 	line_list__free(&pf->lcache);
1347 	if (dwfl)
1348 		dwfl_end(dwfl);
1349 
1350 	return ret;
1351 }
1352 
1353 /* Add a found probe point into trace event list */
1354 static int add_probe_trace_event(Dwarf_Die *sp_die, struct probe_finder *pf)
1355 {
1356 	struct trace_event_finder *tf =
1357 			container_of(pf, struct trace_event_finder, pf);
1358 	struct probe_trace_event *tev;
1359 	int ret, i;
1360 
1361 	/* Check number of tevs */
1362 	if (tf->ntevs == tf->max_tevs) {
1363 		pr_warning("Too many( > %d) probe point found.\n",
1364 			   tf->max_tevs);
1365 		return -ERANGE;
1366 	}
1367 	tev = &tf->tevs[tf->ntevs++];
1368 
1369 	ret = convert_to_trace_point(sp_die, pf->addr, pf->pev->point.retprobe,
1370 				     &tev->point);
1371 	if (ret < 0)
1372 		return ret;
1373 
1374 	pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1375 		 tev->point.offset);
1376 
1377 	/* Find each argument */
1378 	tev->nargs = pf->pev->nargs;
1379 	tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1380 	if (tev->args == NULL)
1381 		return -ENOMEM;
1382 	for (i = 0; i < pf->pev->nargs; i++) {
1383 		pf->pvar = &pf->pev->args[i];
1384 		pf->tvar = &tev->args[i];
1385 		ret = find_variable(sp_die, pf);
1386 		if (ret != 0)
1387 			return ret;
1388 	}
1389 
1390 	return 0;
1391 }
1392 
1393 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1394 int find_probe_trace_events(int fd, struct perf_probe_event *pev,
1395 			    struct probe_trace_event **tevs, int max_tevs)
1396 {
1397 	struct trace_event_finder tf = {
1398 			.pf = {.pev = pev, .callback = add_probe_trace_event},
1399 			.max_tevs = max_tevs};
1400 	int ret;
1401 
1402 	/* Allocate result tevs array */
1403 	*tevs = zalloc(sizeof(struct probe_trace_event) * max_tevs);
1404 	if (*tevs == NULL)
1405 		return -ENOMEM;
1406 
1407 	tf.tevs = *tevs;
1408 	tf.ntevs = 0;
1409 
1410 	ret = find_probes(fd, &tf.pf);
1411 	if (ret < 0) {
1412 		free(*tevs);
1413 		*tevs = NULL;
1414 		return ret;
1415 	}
1416 
1417 	return (ret < 0) ? ret : tf.ntevs;
1418 }
1419 
1420 #define MAX_VAR_LEN 64
1421 
1422 /* Collect available variables in this scope */
1423 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1424 {
1425 	struct available_var_finder *af = data;
1426 	struct variable_list *vl;
1427 	char buf[MAX_VAR_LEN];
1428 	int tag, ret;
1429 
1430 	vl = &af->vls[af->nvls - 1];
1431 
1432 	tag = dwarf_tag(die_mem);
1433 	if (tag == DW_TAG_formal_parameter ||
1434 	    tag == DW_TAG_variable) {
1435 		ret = convert_variable_location(die_mem, af->pf.addr,
1436 						af->pf.fb_ops, NULL);
1437 		if (ret == 0) {
1438 			ret = die_get_varname(die_mem, buf, MAX_VAR_LEN);
1439 			pr_debug2("Add new var: %s\n", buf);
1440 			if (ret > 0)
1441 				strlist__add(vl->vars, buf);
1442 		}
1443 	}
1444 
1445 	if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1446 		return DIE_FIND_CB_CONTINUE;
1447 	else
1448 		return DIE_FIND_CB_SIBLING;
1449 }
1450 
1451 /* Add a found vars into available variables list */
1452 static int add_available_vars(Dwarf_Die *sp_die, struct probe_finder *pf)
1453 {
1454 	struct available_var_finder *af =
1455 			container_of(pf, struct available_var_finder, pf);
1456 	struct variable_list *vl;
1457 	Dwarf_Die die_mem, *scopes = NULL;
1458 	int ret, nscopes;
1459 
1460 	/* Check number of tevs */
1461 	if (af->nvls == af->max_vls) {
1462 		pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1463 		return -ERANGE;
1464 	}
1465 	vl = &af->vls[af->nvls++];
1466 
1467 	ret = convert_to_trace_point(sp_die, pf->addr, pf->pev->point.retprobe,
1468 				     &vl->point);
1469 	if (ret < 0)
1470 		return ret;
1471 
1472 	pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1473 		 vl->point.offset);
1474 
1475 	/* Find local variables */
1476 	vl->vars = strlist__new(true, NULL);
1477 	if (vl->vars == NULL)
1478 		return -ENOMEM;
1479 	af->child = true;
1480 	die_find_child(sp_die, collect_variables_cb, (void *)af, &die_mem);
1481 
1482 	/* Find external variables */
1483 	if (!af->externs)
1484 		goto out;
1485 	/* Don't need to search child DIE for externs. */
1486 	af->child = false;
1487 	nscopes = dwarf_getscopes_die(sp_die, &scopes);
1488 	while (nscopes-- > 1)
1489 		die_find_child(&scopes[nscopes], collect_variables_cb,
1490 			       (void *)af, &die_mem);
1491 	if (scopes)
1492 		free(scopes);
1493 
1494 out:
1495 	if (strlist__empty(vl->vars)) {
1496 		strlist__delete(vl->vars);
1497 		vl->vars = NULL;
1498 	}
1499 
1500 	return ret;
1501 }
1502 
1503 /* Find available variables at given probe point */
1504 int find_available_vars_at(int fd, struct perf_probe_event *pev,
1505 			   struct variable_list **vls, int max_vls,
1506 			   bool externs)
1507 {
1508 	struct available_var_finder af = {
1509 			.pf = {.pev = pev, .callback = add_available_vars},
1510 			.max_vls = max_vls, .externs = externs};
1511 	int ret;
1512 
1513 	/* Allocate result vls array */
1514 	*vls = zalloc(sizeof(struct variable_list) * max_vls);
1515 	if (*vls == NULL)
1516 		return -ENOMEM;
1517 
1518 	af.vls = *vls;
1519 	af.nvls = 0;
1520 
1521 	ret = find_probes(fd, &af.pf);
1522 	if (ret < 0) {
1523 		/* Free vlist for error */
1524 		while (af.nvls--) {
1525 			if (af.vls[af.nvls].point.symbol)
1526 				free(af.vls[af.nvls].point.symbol);
1527 			if (af.vls[af.nvls].vars)
1528 				strlist__delete(af.vls[af.nvls].vars);
1529 		}
1530 		free(af.vls);
1531 		*vls = NULL;
1532 		return ret;
1533 	}
1534 
1535 	return (ret < 0) ? ret : af.nvls;
1536 }
1537 
1538 /* Reverse search */
1539 int find_perf_probe_point(unsigned long addr, struct perf_probe_point *ppt)
1540 {
1541 	Dwarf_Die cudie, spdie, indie;
1542 	Dwarf *dbg = NULL;
1543 	Dwfl *dwfl = NULL;
1544 	Dwarf_Line *line;
1545 	Dwarf_Addr laddr, eaddr, bias = 0;
1546 	const char *tmp;
1547 	int lineno, ret = 0;
1548 	bool found = false;
1549 
1550 	/* Open the live linux kernel */
1551 	dbg = dwfl_init_live_kernel_dwarf(addr, &dwfl, &bias);
1552 	if (!dbg) {
1553 		pr_warning("No debug information found in the vmlinux - "
1554 			"please rebuild with CONFIG_DEBUG_INFO=y.\n");
1555 		ret = -EINVAL;
1556 		goto end;
1557 	}
1558 
1559 	/* Adjust address with bias */
1560 	addr += bias;
1561 	/* Find cu die */
1562 	if (!dwarf_addrdie(dbg, (Dwarf_Addr)addr - bias, &cudie)) {
1563 		pr_warning("Failed to find debug information for address %lx\n",
1564 			   addr);
1565 		ret = -EINVAL;
1566 		goto end;
1567 	}
1568 
1569 	/* Find a corresponding line */
1570 	line = dwarf_getsrc_die(&cudie, (Dwarf_Addr)addr);
1571 	if (line) {
1572 		if (dwarf_lineaddr(line, &laddr) == 0 &&
1573 		    (Dwarf_Addr)addr == laddr &&
1574 		    dwarf_lineno(line, &lineno) == 0) {
1575 			tmp = dwarf_linesrc(line, NULL, NULL);
1576 			if (tmp) {
1577 				ppt->line = lineno;
1578 				ppt->file = strdup(tmp);
1579 				if (ppt->file == NULL) {
1580 					ret = -ENOMEM;
1581 					goto end;
1582 				}
1583 				found = true;
1584 			}
1585 		}
1586 	}
1587 
1588 	/* Find a corresponding function */
1589 	if (die_find_real_subprogram(&cudie, (Dwarf_Addr)addr, &spdie)) {
1590 		tmp = dwarf_diename(&spdie);
1591 		if (!tmp || dwarf_entrypc(&spdie, &eaddr) != 0)
1592 			goto end;
1593 
1594 		if (ppt->line) {
1595 			if (die_find_inlinefunc(&spdie, (Dwarf_Addr)addr,
1596 						&indie)) {
1597 				/* addr in an inline function */
1598 				tmp = dwarf_diename(&indie);
1599 				if (!tmp)
1600 					goto end;
1601 				ret = dwarf_decl_line(&indie, &lineno);
1602 			} else {
1603 				if (eaddr == addr) {	/* Function entry */
1604 					lineno = ppt->line;
1605 					ret = 0;
1606 				} else
1607 					ret = dwarf_decl_line(&spdie, &lineno);
1608 			}
1609 			if (ret == 0) {
1610 				/* Make a relative line number */
1611 				ppt->line -= lineno;
1612 				goto found;
1613 			}
1614 		}
1615 		/* We don't have a line number, let's use offset */
1616 		ppt->offset = addr - (unsigned long)eaddr;
1617 found:
1618 		ppt->function = strdup(tmp);
1619 		if (ppt->function == NULL) {
1620 			ret = -ENOMEM;
1621 			goto end;
1622 		}
1623 		found = true;
1624 	}
1625 
1626 end:
1627 	if (dwfl)
1628 		dwfl_end(dwfl);
1629 	if (ret >= 0)
1630 		ret = found ? 1 : 0;
1631 	return ret;
1632 }
1633 
1634 /* Add a line and store the src path */
1635 static int line_range_add_line(const char *src, unsigned int lineno,
1636 			       struct line_range *lr)
1637 {
1638 	/* Copy source path */
1639 	if (!lr->path) {
1640 		lr->path = strdup(src);
1641 		if (lr->path == NULL)
1642 			return -ENOMEM;
1643 	}
1644 	return line_list__add_line(&lr->line_list, lineno);
1645 }
1646 
1647 /* Search function declaration lines */
1648 static int line_range_funcdecl_cb(Dwarf_Die *sp_die, void *data)
1649 {
1650 	struct dwarf_callback_param *param = data;
1651 	struct line_finder *lf = param->data;
1652 	const char *src;
1653 	int lineno;
1654 
1655 	src = dwarf_decl_file(sp_die);
1656 	if (src && strtailcmp(src, lf->fname) != 0)
1657 		return DWARF_CB_OK;
1658 
1659 	if (dwarf_decl_line(sp_die, &lineno) != 0 ||
1660 	    (lf->lno_s > lineno || lf->lno_e < lineno))
1661 		return DWARF_CB_OK;
1662 
1663 	param->retval = line_range_add_line(src, lineno, lf->lr);
1664 	if (param->retval < 0)
1665 		return DWARF_CB_ABORT;
1666 	return DWARF_CB_OK;
1667 }
1668 
1669 static int find_line_range_func_decl_lines(struct line_finder *lf)
1670 {
1671 	struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1672 	dwarf_getfuncs(&lf->cu_die, line_range_funcdecl_cb, &param, 0);
1673 	return param.retval;
1674 }
1675 
1676 /* Find line range from its line number */
1677 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1678 {
1679 	Dwarf_Lines *lines;
1680 	Dwarf_Line *line;
1681 	size_t nlines, i;
1682 	Dwarf_Addr addr;
1683 	int lineno, ret = 0;
1684 	const char *src;
1685 	Dwarf_Die die_mem;
1686 
1687 	line_list__init(&lf->lr->line_list);
1688 	if (dwarf_getsrclines(&lf->cu_die, &lines, &nlines) != 0) {
1689 		pr_warning("No source lines found.\n");
1690 		return -ENOENT;
1691 	}
1692 
1693 	/* Search probable lines on lines list */
1694 	for (i = 0; i < nlines; i++) {
1695 		line = dwarf_onesrcline(lines, i);
1696 		if (dwarf_lineno(line, &lineno) != 0 ||
1697 		    (lf->lno_s > lineno || lf->lno_e < lineno))
1698 			continue;
1699 
1700 		if (sp_die) {
1701 			/* Address filtering 1: does sp_die include addr? */
1702 			if (dwarf_lineaddr(line, &addr) != 0 ||
1703 			    !dwarf_haspc(sp_die, addr))
1704 				continue;
1705 
1706 			/* Address filtering 2: No child include addr? */
1707 			if (die_find_inlinefunc(sp_die, addr, &die_mem))
1708 				continue;
1709 		}
1710 
1711 		/* TODO: Get fileno from line, but how? */
1712 		src = dwarf_linesrc(line, NULL, NULL);
1713 		if (strtailcmp(src, lf->fname) != 0)
1714 			continue;
1715 
1716 		ret = line_range_add_line(src, lineno, lf->lr);
1717 		if (ret < 0)
1718 			return ret;
1719 	}
1720 
1721 	/*
1722 	 * Dwarf lines doesn't include function declarations. We have to
1723 	 * check functions list or given function.
1724 	 */
1725 	if (sp_die) {
1726 		src = dwarf_decl_file(sp_die);
1727 		if (src && dwarf_decl_line(sp_die, &lineno) == 0 &&
1728 		    (lf->lno_s <= lineno && lf->lno_e >= lineno))
1729 			ret = line_range_add_line(src, lineno, lf->lr);
1730 	} else
1731 		ret = find_line_range_func_decl_lines(lf);
1732 
1733 	/* Update status */
1734 	if (ret >= 0)
1735 		if (!list_empty(&lf->lr->line_list))
1736 			ret = lf->found = 1;
1737 		else
1738 			ret = 0;	/* Lines are not found */
1739 	else {
1740 		free(lf->lr->path);
1741 		lf->lr->path = NULL;
1742 	}
1743 	return ret;
1744 }
1745 
1746 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1747 {
1748 	struct dwarf_callback_param *param = data;
1749 
1750 	param->retval = find_line_range_by_line(in_die, param->data);
1751 	return DWARF_CB_ABORT;	/* No need to find other instances */
1752 }
1753 
1754 /* Search function from function name */
1755 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1756 {
1757 	struct dwarf_callback_param *param = data;
1758 	struct line_finder *lf = param->data;
1759 	struct line_range *lr = lf->lr;
1760 
1761 	pr_debug("find (%llx) %s\n",
1762 		 (unsigned long long)dwarf_dieoffset(sp_die),
1763 		 dwarf_diename(sp_die));
1764 	if (dwarf_tag(sp_die) == DW_TAG_subprogram &&
1765 	    die_compare_name(sp_die, lr->function)) {
1766 		lf->fname = dwarf_decl_file(sp_die);
1767 		dwarf_decl_line(sp_die, &lr->offset);
1768 		pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1769 		lf->lno_s = lr->offset + lr->start;
1770 		if (lf->lno_s < 0)	/* Overflow */
1771 			lf->lno_s = INT_MAX;
1772 		lf->lno_e = lr->offset + lr->end;
1773 		if (lf->lno_e < 0)	/* Overflow */
1774 			lf->lno_e = INT_MAX;
1775 		pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1776 		lr->start = lf->lno_s;
1777 		lr->end = lf->lno_e;
1778 		if (dwarf_func_inline(sp_die)) {
1779 			struct dwarf_callback_param _param;
1780 			_param.data = (void *)lf;
1781 			_param.retval = 0;
1782 			dwarf_func_inline_instances(sp_die,
1783 						    line_range_inline_cb,
1784 						    &_param);
1785 			param->retval = _param.retval;
1786 		} else
1787 			param->retval = find_line_range_by_line(sp_die, lf);
1788 		return DWARF_CB_ABORT;
1789 	}
1790 	return DWARF_CB_OK;
1791 }
1792 
1793 static int find_line_range_by_func(struct line_finder *lf)
1794 {
1795 	struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1796 	dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1797 	return param.retval;
1798 }
1799 
1800 int find_line_range(int fd, struct line_range *lr)
1801 {
1802 	struct line_finder lf = {.lr = lr, .found = 0};
1803 	int ret = 0;
1804 	Dwarf_Off off = 0, noff;
1805 	size_t cuhl;
1806 	Dwarf_Die *diep;
1807 	Dwarf *dbg = NULL;
1808 	Dwfl *dwfl;
1809 	Dwarf_Addr bias;	/* Currently ignored */
1810 	const char *comp_dir;
1811 
1812 	dbg = dwfl_init_offline_dwarf(fd, &dwfl, &bias);
1813 	if (!dbg) {
1814 		pr_warning("No debug information found in the vmlinux - "
1815 			"please rebuild with CONFIG_DEBUG_INFO=y.\n");
1816 		return -EBADF;
1817 	}
1818 
1819 	/* Loop on CUs (Compilation Unit) */
1820 	while (!lf.found && ret >= 0) {
1821 		if (dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL) != 0)
1822 			break;
1823 
1824 		/* Get the DIE(Debugging Information Entry) of this CU */
1825 		diep = dwarf_offdie(dbg, off + cuhl, &lf.cu_die);
1826 		if (!diep)
1827 			continue;
1828 
1829 		/* Check if target file is included. */
1830 		if (lr->file)
1831 			lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1832 		else
1833 			lf.fname = 0;
1834 
1835 		if (!lr->file || lf.fname) {
1836 			if (lr->function)
1837 				ret = find_line_range_by_func(&lf);
1838 			else {
1839 				lf.lno_s = lr->start;
1840 				lf.lno_e = lr->end;
1841 				ret = find_line_range_by_line(NULL, &lf);
1842 			}
1843 		}
1844 		off = noff;
1845 	}
1846 
1847 	/* Store comp_dir */
1848 	if (lf.found) {
1849 		comp_dir = cu_get_comp_dir(&lf.cu_die);
1850 		if (comp_dir) {
1851 			lr->comp_dir = strdup(comp_dir);
1852 			if (!lr->comp_dir)
1853 				ret = -ENOMEM;
1854 		}
1855 	}
1856 
1857 	pr_debug("path: %s\n", lr->path);
1858 	dwfl_end(dwfl);
1859 	return (ret < 0) ? ret : lf.found;
1860 }
1861 
1862