summaryrefslogtreecommitdiff
path: root/tools/perf/util/probe-finder.c
blob: e7ee52fd0e090d6e1e6b3a3dcbcb4f16cd2636d6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
/*
 * probe-finder.c : C expression to kprobe event converter
 *
 * Written by Masami Hiramatsu <mhiramat@redhat.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 */

#include <sys/utsname.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <unistd.h>
#include <getopt.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <ctype.h>
#include <dwarf-regs.h>

#include "string.h"
#include "event.h"
#include "debug.h"
#include "util.h"
#include "probe-finder.h"

/* Kprobe tracer basic type is up to u64 */
#define MAX_BASIC_TYPE_BITS	64

/*
 * Compare the tail of two strings.
 * Return 0 if whole of either string is same as another's tail part.
 */
static int strtailcmp(const char *s1, const char *s2)
{
	int i1 = strlen(s1);
	int i2 = strlen(s2);
	while (--i1 >= 0 && --i2 >= 0) {
		if (s1[i1] != s2[i2])
			return s1[i1] - s2[i2];
	}
	return 0;
}

/* Line number list operations */

/* Add a line to line number list */
static int line_list__add_line(struct list_head *head, int line)
{
	struct line_node *ln;
	struct list_head *p;

	/* Reverse search, because new line will be the last one */
	list_for_each_entry_reverse(ln, head, list) {
		if (ln->line < line) {
			p = &ln->list;
			goto found;
		} else if (ln->line == line)	/* Already exist */
			return 1;
	}
	/* List is empty, or the smallest entry */
	p = head;
found:
	pr_debug("line list: add a line %u\n", line);
	ln = zalloc(sizeof(struct line_node));
	if (ln == NULL)
		return -ENOMEM;
	ln->line = line;
	INIT_LIST_HEAD(&ln->list);
	list_add(&ln->list, p);
	return 0;
}

/* Check if the line in line number list */
static int line_list__has_line(struct list_head *head, int line)
{
	struct line_node *ln;

	/* Reverse search, because new line will be the last one */
	list_for_each_entry(ln, head, list)
		if (ln->line == line)
			return 1;

	return 0;
}

/* Init line number list */
static void line_list__init(struct list_head *head)
{
	INIT_LIST_HEAD(head);
}

/* Free line number list */
static void line_list__free(struct list_head *head)
{
	struct line_node *ln;
	while (!list_empty(head)) {
		ln = list_first_entry(head, struct line_node, list);
		list_del(&ln->list);
		free(ln);
	}
}

/* Dwarf wrappers */

/* Find the realpath of the target file. */
static const char *cu_find_realpath(Dwarf_Die *cu_die, const char *fname)
{
	Dwarf_Files *files;
	size_t nfiles, i;
	const char *src = NULL;
	int ret;

	if (!fname)
		return NULL;

	ret = dwarf_getsrcfiles(cu_die, &files, &nfiles);
	if (ret != 0)
		return NULL;

	for (i = 0; i < nfiles; i++) {
		src = dwarf_filesrc(files, i, NULL, NULL);
		if (strtailcmp(src, fname) == 0)
			break;
	}
	if (i == nfiles)
		return NULL;
	return src;
}

/* Compare diename and tname */
static bool die_compare_name(Dwarf_Die *dw_die, const char *tname)
{
	const char *name;
	name = dwarf_diename(dw_die);
	return name ? strcmp(tname, name) : -1;
}

/* Get type die, but skip qualifiers and typedef */
static Dwarf_Die *die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
{
	Dwarf_Attribute attr;
	int tag;

	do {
		if (dwarf_attr(vr_die, DW_AT_type, &attr) == NULL ||
		    dwarf_formref_die(&attr, die_mem) == NULL)
			return NULL;

		tag = dwarf_tag(die_mem);
		vr_die = die_mem;
	} while (tag == DW_TAG_const_type ||
		 tag == DW_TAG_restrict_type ||
		 tag == DW_TAG_volatile_type ||
		 tag == DW_TAG_shared_type ||
		 tag == DW_TAG_typedef);

	return die_mem;
}

static bool die_is_signed_type(Dwarf_Die *tp_die)
{
	Dwarf_Attribute attr;
	Dwarf_Word ret;

	if (dwarf_attr(tp_die, DW_AT_encoding, &attr) == NULL ||
	    dwarf_formudata(&attr, &ret) != 0)
		return false;

	return (ret == DW_ATE_signed_char || ret == DW_ATE_signed ||
		ret == DW_ATE_signed_fixed);
}

static int die_get_byte_size(Dwarf_Die *tp_die)
{
	Dwarf_Attribute attr;
	Dwarf_Word ret;

	if (dwarf_attr(tp_die, DW_AT_byte_size, &attr) == NULL ||
	    dwarf_formudata(&attr, &ret) != 0)
		return 0;

	return (int)ret;
}

/* Get data_member_location offset */
static int die_get_data_member_location(Dwarf_Die *mb_die, Dwarf_Word *offs)
{
	Dwarf_Attribute attr;
	Dwarf_Op *expr;
	size_t nexpr;
	int ret;

	if (dwarf_attr(mb_die, DW_AT_data_member_location, &attr) == NULL)
		return -ENOENT;

	if (dwarf_formudata(&attr, offs) != 0) {
		/* DW_AT_data_member_location should be DW_OP_plus_uconst */
		ret = dwarf_getlocation(&attr, &expr, &nexpr);
		if (ret < 0 || nexpr == 0)
			return -ENOENT;

		if (expr[0].atom != DW_OP_plus_uconst || nexpr != 1) {
			pr_debug("Unable to get offset:Unexpected OP %x (%zd)\n",
				 expr[0].atom, nexpr);
			return -ENOTSUP;
		}
		*offs = (Dwarf_Word)expr[0].number;
	}
	return 0;
}

/* Return values for die_find callbacks */
enum {
	DIE_FIND_CB_FOUND = 0,		/* End of Search */
	DIE_FIND_CB_CHILD = 1,		/* Search only children */
	DIE_FIND_CB_SIBLING = 2,	/* Search only siblings */
	DIE_FIND_CB_CONTINUE = 3,	/* Search children and siblings */
};

/* Search a child die */
static Dwarf_Die *die_find_child(Dwarf_Die *rt_die,
				 int (*callback)(Dwarf_Die *, void *),
				 void *data, Dwarf_Die *die_mem)
{
	Dwarf_Die child_die;
	int ret;

	ret = dwarf_child(rt_die, die_mem);
	if (ret != 0)
		return NULL;

	do {
		ret = callback(die_mem, data);
		if (ret == DIE_FIND_CB_FOUND)
			return die_mem;

		if ((ret & DIE_FIND_CB_CHILD) &&
		    die_find_child(die_mem, callback, data, &child_die)) {
			memcpy(die_mem, &child_die, sizeof(Dwarf_Die));
			return die_mem;
		}
	} while ((ret & DIE_FIND_CB_SIBLING) &&
		 dwarf_siblingof(die_mem, die_mem) == 0);

	return NULL;
}

struct __addr_die_search_param {
	Dwarf_Addr	addr;
	Dwarf_Die	*die_mem;
};

static int __die_search_func_cb(Dwarf_Die *fn_die, void *data)
{
	struct __addr_die_search_param *ad = data;

	if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
	    dwarf_haspc(fn_die, ad->addr)) {
		memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
		return DWARF_CB_ABORT;
	}
	return DWARF_CB_OK;
}

/* Search a real subprogram including this line, */
static Dwarf_Die *die_find_real_subprogram(Dwarf_Die *cu_die, Dwarf_Addr addr,
					   Dwarf_Die *die_mem)
{
	struct __addr_die_search_param ad;
	ad.addr = addr;
	ad.die_mem = die_mem;
	/* dwarf_getscopes can't find subprogram. */
	if (!dwarf_getfuncs(cu_die, __die_search_func_cb, &ad, 0))
		return NULL;
	else
		return die_mem;
}

/* die_find callback for inline function search */
static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data)
{
	Dwarf_Addr *addr = data;

	if (dwarf_tag(die_mem) == DW_TAG_inlined_subroutine &&
	    dwarf_haspc(die_mem, *addr))
		return DIE_FIND_CB_FOUND;

	return DIE_FIND_CB_CONTINUE;
}

/* Similar to dwarf_getfuncs, but returns inlined_subroutine if exists. */
static Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
				      Dwarf_Die *die_mem)
{
	return die_find_child(sp_die, __die_find_inline_cb, &addr, die_mem);
}

static int __die_find_variable_cb(Dwarf_Die *die_mem, void *data)
{
	const char *name = data;
	int tag;

	tag = dwarf_tag(die_mem);
	if ((tag == DW_TAG_formal_parameter ||
	     tag == DW_TAG_variable) &&
	    (die_compare_name(die_mem, name) == 0))
		return DIE_FIND_CB_FOUND;

	return DIE_FIND_CB_CONTINUE;
}

/* Find a variable called 'name' */
static Dwarf_Die *die_find_variable(Dwarf_Die *sp_die, const char *name,
				    Dwarf_Die *die_mem)
{
	return die_find_child(sp_die, __die_find_variable_cb, (void *)name,
			      die_mem);
}

static int __die_find_member_cb(Dwarf_Die *die_mem, void *data)
{
	const char *name = data;

	if ((dwarf_tag(die_mem) == DW_TAG_member) &&
	    (die_compare_name(die_mem, name) == 0))
		return DIE_FIND_CB_FOUND;

	return DIE_FIND_CB_SIBLING;
}

/* Find a member called 'name' */
static Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name,
				  Dwarf_Die *die_mem)
{
	return die_find_child(st_die, __die_find_member_cb, (void *)name,
			      die_mem);
}

/*
 * Probe finder related functions
 */

/* Show a location */
static int convert_location(Dwarf_Op *op, struct probe_finder *pf)
{
	unsigned int regn;
	Dwarf_Word offs = 0;
	bool ref = false;
	const char *regs;
	struct kprobe_trace_arg *tvar = pf->tvar;

	/* If this is based on frame buffer, set the offset */
	if (op->atom == DW_OP_fbreg) {
		if (pf->fb_ops == NULL) {
			pr_warning("The attribute of frame base is not "
				   "supported.\n");
			return -ENOTSUP;
		}
		ref = true;
		offs = op->number;
		op = &pf->fb_ops[0];
	}

	if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
		regn = op->atom - DW_OP_breg0;
		offs += op->number;
		ref = true;
	} else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
		regn = op->atom - DW_OP_reg0;
	} else if (op->atom == DW_OP_bregx) {
		regn = op->number;
		offs += op->number2;
		ref = true;
	} else if (op->atom == DW_OP_regx) {
		regn = op->number;
	} else {
		pr_warning("DW_OP %x is not supported.\n", op->atom);
		return -ENOTSUP;
	}

	regs = get_arch_regstr(regn);
	if (!regs) {
		pr_warning("Mapping for DWARF register number %u missing on this architecture.", regn);
		return -ERANGE;
	}

	tvar->value = strdup(regs);
	if (tvar->value == NULL)
		return -ENOMEM;

	if (ref) {
		tvar->ref = zalloc(sizeof(struct kprobe_trace_arg_ref));
		if (tvar->ref == NULL)
			return -ENOMEM;
		tvar->ref->offset = (long)offs;
	}
	return 0;
}

static int convert_variable_type(Dwarf_Die *vr_die,
				 struct kprobe_trace_arg *targ)
{
	Dwarf_Die type;
	char buf[16];
	int ret;

	if (die_get_real_type(vr_die, &type) == NULL) {
		pr_warning("Failed to get a type information of %s.\n",
			   dwarf_diename(vr_die));
		return -ENOENT;
	}

	ret = die_get_byte_size(&type) * 8;
	if (ret) {
		/* Check the bitwidth */
		if (ret > MAX_BASIC_TYPE_BITS) {
			pr_info("%s exceeds max-bitwidth."
				" Cut down to %d bits.\n",
				dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
			ret = MAX_BASIC_TYPE_BITS;
		}

		ret = snprintf(buf, 16, "%c%d",
			       die_is_signed_type(&type) ? 's' : 'u', ret);
		if (ret < 0 || ret >= 16) {
			if (ret >= 16)
				ret = -E2BIG;
			pr_warning("Failed to convert variable type: %s\n",
				   strerror(-ret));
			return ret;
		}
		targ->type = strdup(buf);
		if (targ->type == NULL)
			return -ENOMEM;
	}
	return 0;
}

static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
				    struct perf_probe_arg_field *field,
				    struct kprobe_trace_arg_ref **ref_ptr,
				    Dwarf_Die *die_mem)
{
	struct kprobe_trace_arg_ref *ref = *ref_ptr;
	Dwarf_Die type;
	Dwarf_Word offs;
	int ret;

	pr_debug("converting %s in %s\n", field->name, varname);
	if (die_get_real_type(vr_die, &type) == NULL) {
		pr_warning("Failed to get the type of %s.\n", varname);
		return -ENOENT;
	}

	/* Check the pointer and dereference */
	if (dwarf_tag(&type) == DW_TAG_pointer_type) {
		if (!field->ref) {
			pr_err("Semantic error: %s must be referred by '->'\n",
			       field->name);
			return -EINVAL;
		}
		/* Get the type pointed by this pointer */
		if (die_get_real_type(&type, &type) == NULL) {
			pr_warning("Failed to get the type of %s.\n", varname);
			return -ENOENT;
		}
		/* Verify it is a data structure  */
		if (dwarf_tag(&type) != DW_TAG_structure_type) {
			pr_warning("%s is not a data structure.\n", varname);
			return -EINVAL;
		}

		ref = zalloc(sizeof(struct kprobe_trace_arg_ref));
		if (ref == NULL)
			return -ENOMEM;
		if (*ref_ptr)
			(*ref_ptr)->next = ref;
		else
			*ref_ptr = ref;
	} else {
		/* Verify it is a data structure  */
		if (dwarf_tag(&type) != DW_TAG_structure_type) {
			pr_warning("%s is not a data structure.\n", varname);
			return -EINVAL;
		}
		if (field->ref) {
			pr_err("Semantic error: %s must be referred by '.'\n",
			       field->name);
			return -EINVAL;
		}
		if (!ref) {
			pr_warning("Structure on a register is not "
				   "supported yet.\n");
			return -ENOTSUP;
		}
	}

	if (die_find_member(&type, field->name, die_mem) == NULL) {
		pr_warning("%s(tyep:%s) has no member %s.\n", varname,
			   dwarf_diename(&type), field->name);
		return -EINVAL;
	}

	/* Get the offset of the field */
	ret = die_get_data_member_location(die_mem, &offs);
	if (ret < 0) {
		pr_warning("Failed to get the offset of %s.\n", field->name);
		return ret;
	}
	ref->offset += (long)offs;

	/* Converting next field */
	if (field->next)
		return convert_variable_fields(die_mem, field->name,
					field->next, &ref, die_mem);
	else
		return 0;
}

/* Show a variables in kprobe event format */
static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
{
	Dwarf_Attribute attr;
	Dwarf_Die die_mem;
	Dwarf_Op *expr;
	size_t nexpr;
	int ret;

	if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
		goto error;
	/* TODO: handle more than 1 exprs */
	ret = dwarf_getlocation_addr(&attr, pf->addr, &expr, &nexpr, 1);
	if (ret <= 0 || nexpr == 0)
		goto error;

	ret = convert_location(expr, pf);
	if (ret == 0 && pf->pvar->field) {
		ret = convert_variable_fields(vr_die, pf->pvar->var,
					      pf->pvar->field, &pf->tvar->ref,
					      &die_mem);
		vr_die = &die_mem;
	}
	if (ret == 0) {
		if (pf->pvar->type) {
			pf->tvar->type = strdup(pf->pvar->type);
			if (pf->tvar->type == NULL)
				ret = -ENOMEM;
		} else
			ret = convert_variable_type(vr_die, pf->tvar);
	}
	/* *expr will be cached in libdw. Don't free it. */
	return ret;
error:
	/* TODO: Support const_value */
	pr_err("Failed to find the location of %s at this address.\n"
	       " Perhaps, it has been optimized out.\n", pf->pvar->var);
	return -ENOENT;
}

/* Find a variable in a subprogram die */
static int find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
{
	Dwarf_Die vr_die;
	char buf[32], *ptr;
	int ret;

	/* TODO: Support arrays */
	if (pf->pvar->name)
		pf->tvar->name = strdup(pf->pvar->name);
	else {
		ret = synthesize_perf_probe_arg(pf->pvar, buf, 32);
		if (ret < 0)
			return ret;
		ptr = strchr(buf, ':');	/* Change type separator to _ */
		if (ptr)
			*ptr = '_';
		pf->tvar->name = strdup(buf);
	}
	if (pf->tvar->name == NULL)
		return -ENOMEM;

	if (!is_c_varname(pf->pvar->var)) {
		/* Copy raw parameters */
		pf->tvar->value = strdup(pf->pvar->var);
		if (pf->tvar->value == NULL)
			return -ENOMEM;
		else
			return 0;
	}

	pr_debug("Searching '%s' variable in context.\n",
		 pf->pvar->var);
	/* Search child die for local variables and parameters. */
	if (!die_find_variable(sp_die, pf->pvar->var, &vr_die)) {
		pr_warning("Failed to find '%s' in this function.\n",
			   pf->pvar->var);
		return -ENOENT;
	}
	return convert_variable(&vr_die, pf);
}

/* Show a probe point to output buffer */
static int convert_probe_point(Dwarf_Die *sp_die, struct probe_finder *pf)
{
	struct kprobe_trace_event *tev;
	Dwarf_Addr eaddr;
	Dwarf_Die die_mem;
	const char *name;
	int ret, i;
	Dwarf_Attribute fb_attr;
	size_t nops;

	if (pf->ntevs == MAX_PROBES) {
		pr_warning("Too many( > %d) probe point found.\n", MAX_PROBES);
		return -ERANGE;
	}
	tev = &pf->tevs[pf->ntevs++];

	/* If no real subprogram, find a real one */
	if (!sp_die || dwarf_tag(sp_die) != DW_TAG_subprogram) {
		sp_die = die_find_real_subprogram(&pf->cu_die,
						 pf->addr, &die_mem);
		if (!sp_die) {
			pr_warning("Failed to find probe point in any "
				   "functions.\n");
			return -ENOENT;
		}
	}

	/* Copy the name of probe point */
	name = dwarf_diename(sp_die);
	if (name) {
		if (dwarf_entrypc(sp_die, &eaddr) != 0) {
			pr_warning("Failed to get entry pc of %s\n",
				   dwarf_diename(sp_die));
			return -ENOENT;
		}
		tev->point.symbol = strdup(name);
		if (tev->point.symbol == NULL)
			return -ENOMEM;
		tev->point.offset = (unsigned long)(pf->addr - eaddr);
	} else
		/* This function has no name. */
		tev->point.offset = (unsigned long)pf->addr;

	pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
		 tev->point.offset);

	/* Get the frame base attribute/ops */
	dwarf_attr(sp_die, DW_AT_frame_base, &fb_attr);
	ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
	if (ret <= 0 || nops == 0) {
		pf->fb_ops = NULL;
	} else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
		   pf->cfi != NULL) {
		Dwarf_Frame *frame;
		if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
		    dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
			pr_warning("Failed to get CFA on 0x%jx\n",
				   (uintmax_t)pf->addr);
			return -ENOENT;
		}
	}

	/* Find each argument */
	tev->nargs = pf->pev->nargs;
	tev->args = zalloc(sizeof(struct kprobe_trace_arg) * tev->nargs);
	if (tev->args == NULL)
		return -ENOMEM;
	for (i = 0; i < pf->pev->nargs; i++) {
		pf->pvar = &pf->pev->args[i];
		pf->tvar = &tev->args[i];
		ret = find_variable(sp_die, pf);
		if (ret != 0)
			return ret;
	}

	/* *pf->fb_ops will be cached in libdw. Don't free it. */
	pf->fb_ops = NULL;
	return 0;
}

/* Find probe point from its line number */
static int find_probe_point_by_line(struct probe_finder *pf)
{
	Dwarf_Lines *lines;
	Dwarf_Line *line;
	size_t nlines, i;
	Dwarf_Addr addr;
	int lineno;
	int ret = 0;

	if (dwarf_getsrclines(&pf->cu_die, &lines, &nlines) != 0) {
		pr_warning("No source lines found in this CU.\n");
		return -ENOENT;
	}

	for (i = 0; i < nlines && ret == 0; i++) {
		line = dwarf_onesrcline(lines, i);
		if (dwarf_lineno(line, &lineno) != 0 ||
		    lineno != pf->lno)
			continue;

		/* TODO: Get fileno from line, but how? */
		if (strtailcmp(dwarf_linesrc(line, NULL, NULL), pf->fname) != 0)
			continue;

		if (dwarf_lineaddr(line, &addr) != 0) {
			pr_warning("Failed to get the address of the line.\n");
			return -ENOENT;
		}
		pr_debug("Probe line found: line[%d]:%d addr:0x%jx\n",
			 (int)i, lineno, (uintmax_t)addr);
		pf->addr = addr;

		ret = convert_probe_point(NULL, pf);
		/* Continuing, because target line might be inlined. */
	}
	return ret;
}

/* Find lines which match lazy pattern */
static int find_lazy_match_lines(struct list_head *head,
				 const char *fname, const char *pat)
{
	char *fbuf, *p1, *p2;
	int fd, ret, line, nlines = 0;
	struct stat st;

	fd = open(fname, O_RDONLY);
	if (fd < 0) {
		pr_warning("Failed to open %s: %s\n", fname, strerror(-fd));
		return fd;
	}

	ret = fstat(fd, &st);
	if (ret < 0) {
		pr_warning("Failed to get the size of %s: %s\n",
			   fname, strerror(errno));
		return ret;
	}
	fbuf = xmalloc(st.st_size + 2);
	ret = read(fd, fbuf, st.st_size);
	if (ret < 0) {
		pr_warning("Failed to read %s: %s\n", fname, strerror(errno));
		return ret;
	}
	close(fd);
	fbuf[st.st_size] = '\n';	/* Dummy line */
	fbuf[st.st_size + 1] = '\0';
	p1 = fbuf;
	line = 1;
	while ((p2 = strchr(p1, '\n')) != NULL) {
		*p2 = '\0';
		if (strlazymatch(p1, pat)) {
			line_list__add_line(head, line);
			nlines++;
		}
		line++;
		p1 = p2 + 1;
	}
	free(fbuf);
	return nlines;
}

/* Find probe points from lazy pattern  */
static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
{
	Dwarf_Lines *lines;
	Dwarf_Line *line;
	size_t nlines, i;
	Dwarf_Addr addr;
	Dwarf_Die die_mem;
	int lineno;
	int ret = 0;

	if (list_empty(&pf->lcache)) {
		/* Matching lazy line pattern */
		ret = find_lazy_match_lines(&pf->lcache, pf->fname,
					    pf->pev->point.lazy_line);
		if (ret == 0) {
			pr_debug("No matched lines found in %s.\n", pf->fname);
			return 0;
		} else if (ret < 0)
			return ret;
	}

	if (dwarf_getsrclines(&pf->cu_die, &lines, &nlines) != 0) {
		pr_warning("No source lines found in this CU.\n");
		return -ENOENT;
	}

	for (i = 0; i < nlines && ret >= 0; i++) {
		line = dwarf_onesrcline(lines, i);

		if (dwarf_lineno(line, &lineno) != 0 ||
		    !line_list__has_line(&pf->lcache, lineno))
			continue;

		/* TODO: Get fileno from line, but how? */
		if (strtailcmp(dwarf_linesrc(line, NULL, NULL), pf->fname) != 0)
			continue;

		if (dwarf_lineaddr(line, &addr) != 0) {
			pr_debug("Failed to get the address of line %d.\n",
				 lineno);
			continue;
		}
		if (sp_die) {
			/* Address filtering 1: does sp_die include addr? */
			if (!dwarf_haspc(sp_die, addr))
				continue;
			/* Address filtering 2: No child include addr? */
			if (die_find_inlinefunc(sp_die, addr, &die_mem))
				continue;
		}

		pr_debug("Probe line found: line[%d]:%d addr:0x%llx\n",
			 (int)i, lineno, (unsigned long long)addr);
		pf->addr = addr;

		ret = convert_probe_point(sp_die, pf);
		/* Continuing, because target line might be inlined. */
	}
	/* TODO: deallocate lines, but how? */
	return ret;
}

/* Callback parameter with return value */
struct dwarf_callback_param {
	void *data;
	int retval;
};

static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
{
	struct dwarf_callback_param *param = data;
	struct probe_finder *pf = param->data;
	struct perf_probe_point *pp = &pf->pev->point;
	Dwarf_Addr addr;

	if (pp->lazy_line)
		param->retval = find_probe_point_lazy(in_die, pf);
	else {
		/* Get probe address */
		if (dwarf_entrypc(in_die, &addr) != 0) {
			pr_warning("Failed to get entry pc of %s.\n",
				   dwarf_diename(in_die));
			param->retval = -ENOENT;
			return DWARF_CB_ABORT;
		}
		pf->addr = addr;
		pf->addr += pp->offset;
		pr_debug("found inline addr: 0x%jx\n",
			 (uintmax_t)pf->addr);

		param->retval = convert_probe_point(in_die, pf);
	}

	return DWARF_CB_OK;
}

/* Search function from function name */
static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
{
	struct dwarf_callback_param *param = data;
	struct probe_finder *pf = param->data;
	struct perf_probe_point *pp = &pf->pev->point;

	/* Check tag and diename */
	if (dwarf_tag(sp_die) != DW_TAG_subprogram ||
	    die_compare_name(sp_die, pp->function) != 0)
		return DWARF_CB_OK;

	pf->fname = dwarf_decl_file(sp_die);
	if (pp->line) { /* Function relative line */
		dwarf_decl_line(sp_die, &pf->lno);
		pf->lno += pp->line;
		param->retval = find_probe_point_by_line(pf);
	} else if (!dwarf_func_inline(sp_die)) {
		/* Real function */
		if (pp->lazy_line)
			param->retval = find_probe_point_lazy(sp_die, pf);
		else {
			if (dwarf_entrypc(sp_die, &pf->addr) != 0) {
				pr_warning("Failed to get entry pc of %s.\n",
					   dwarf_diename(sp_die));
				param->retval = -ENOENT;
				return DWARF_CB_ABORT;
			}
			pf->addr += pp->offset;
			/* TODO: Check the address in this function */
			param->retval = convert_probe_point(sp_die, pf);
		}
	} else {
		struct dwarf_callback_param _param = {.data = (void *)pf,
						      .retval = 0};
		/* Inlined function: search instances */
		dwarf_func_inline_instances(sp_die, probe_point_inline_cb,
					    &_param);
		param->retval = _param.retval;
	}

	return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
}

static int find_probe_point_by_func(struct probe_finder *pf)
{
	struct dwarf_callback_param _param = {.data = (void *)pf,
					      .retval = 0};
	dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
	return _param.retval;
}

/* Find kprobe_trace_events specified by perf_probe_event from debuginfo */
int find_kprobe_trace_events(int fd, struct perf_probe_event *pev,
			     struct kprobe_trace_event **tevs)
{
	struct probe_finder pf = {.pev = pev};
	struct perf_probe_point *pp = &pev->point;
	Dwarf_Off off, noff;
	size_t cuhl;
	Dwarf_Die *diep;
	Dwarf *dbg;
	int ret = 0;

	pf.tevs = zalloc(sizeof(struct kprobe_trace_event) * MAX_PROBES);
	if (pf.tevs == NULL)
		return -ENOMEM;
	*tevs = pf.tevs;
	pf.ntevs = 0;

	dbg = dwarf_begin(fd, DWARF_C_READ);
	if (!dbg) {
		pr_warning("No dwarf info found in the vmlinux - "
			"please rebuild with CONFIG_DEBUG_INFO=y.\n");
		return -EBADF;
	}

	/* Get the call frame information from this dwarf */
	pf.cfi = dwarf_getcfi(dbg);

	off = 0;
	line_list__init(&pf.lcache);
	/* Loop on CUs (Compilation Unit) */
	while (!dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL) &&
	       ret >= 0) {
		/* Get the DIE(Debugging Information Entry) of this CU */
		diep = dwarf_offdie(dbg, off + cuhl, &pf.cu_die);
		if (!diep)
			continue;

		/* Check if target file is included. */
		if (pp->file)
			pf.fname = cu_find_realpath(&pf.cu_die, pp->file);
		else
			pf.fname = NULL;

		if (!pp->file || pf.fname) {
			if (pp->function)
				ret = find_probe_point_by_func(&pf);
			else if (pp->lazy_line)
				ret = find_probe_point_lazy(NULL, &pf);
			else {
				pf.lno = pp->line;
				ret = find_probe_point_by_line(&pf);
			}
		}
		off = noff;
	}
	line_list__free(&pf.lcache);
	dwarf_end(dbg);

	return (ret < 0) ? ret : pf.ntevs;
}

/* Reverse search */
int find_perf_probe_point(int fd, unsigned long addr,
			  struct perf_probe_point *ppt)
{
	Dwarf_Die cudie, spdie, indie;
	Dwarf *dbg;
	Dwarf_Line *line;
	Dwarf_Addr laddr, eaddr;
	const char *tmp;
	int lineno, ret = 0;
	bool found = false;

	dbg = dwarf_begin(fd, DWARF_C_READ);
	if (!dbg)
		return -EBADF;

	/* Find cu die */
	if (!dwarf_addrdie(dbg, (Dwarf_Addr)addr, &cudie)) {
		ret = -EINVAL;
		goto end;
	}

	/* Find a corresponding line */
	line = dwarf_getsrc_die(&cudie, (Dwarf_Addr)addr);
	if (line) {
		if (dwarf_lineaddr(line, &laddr) == 0 &&
		    (Dwarf_Addr)addr == laddr &&
		    dwarf_lineno(line, &lineno) == 0) {
			tmp = dwarf_linesrc(line, NULL, NULL);
			if (tmp) {
				ppt->line = lineno;
				ppt->file = strdup(tmp);
				if (ppt->file == NULL) {
					ret = -ENOMEM;
					goto end;
				}
				found = true;
			}
		}
	}

	/* Find a corresponding function */
	if (die_find_real_subprogram(&cudie, (Dwarf_Addr)addr, &spdie)) {
		tmp = dwarf_diename(&spdie);
		if (!tmp || dwarf_entrypc(&spdie, &eaddr) != 0)
			goto end;

		if (ppt->line) {
			if (die_find_inlinefunc(&spdie, (Dwarf_Addr)addr,
						&indie)) {
				/* addr in an inline function */
				tmp = dwarf_diename(&indie);
				if (!tmp)
					goto end;
				ret = dwarf_decl_line(&indie, &lineno);
			} else {
				if (eaddr == addr) {	/* Function entry */
					lineno = ppt->line;
					ret = 0;
				} else
					ret = dwarf_decl_line(&spdie, &lineno);
			}
			if (ret == 0) {
				/* Make a relative line number */
				ppt->line -= lineno;
				goto found;
			}
		}
		/* We don't have a line number, let's use offset */
		ppt->offset = addr - (unsigned long)eaddr;
found:
		ppt->function = strdup(tmp);
		if (ppt->function == NULL) {
			ret = -ENOMEM;
			goto end;
		}
		found = true;
	}

end:
	dwarf_end(dbg);
	if (ret >= 0)
		ret = found ? 1 : 0;
	return ret;
}

/* Add a line and store the src path */
static int line_range_add_line(const char *src, unsigned int lineno,
			       struct line_range *lr)
{
	/* Copy real path */
	if (!lr->path) {
		lr->path = strdup(src);
		if (lr->path == NULL)
			return -ENOMEM;
	}
	return line_list__add_line(&lr->line_list, lineno);
}

/* Search function declaration lines */
static int line_range_funcdecl_cb(Dwarf_Die *sp_die, void *data)
{
	struct dwarf_callback_param *param = data;
	struct line_finder *lf = param->data;
	const char *src;
	int lineno;

	src = dwarf_decl_file(sp_die);
	if (src && strtailcmp(src, lf->fname) != 0)
		return DWARF_CB_OK;

	if (dwarf_decl_line(sp_die, &lineno) != 0 ||
	    (lf->lno_s > lineno || lf->lno_e < lineno))
		return DWARF_CB_OK;

	param->retval = line_range_add_line(src, lineno, lf->lr);
	return DWARF_CB_OK;
}

static int find_line_range_func_decl_lines(struct line_finder *lf)
{
	struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
	dwarf_getfuncs(&lf->cu_die, line_range_funcdecl_cb, &param, 0);
	return param.retval;
}

/* Find line range from its line number */
static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
{
	Dwarf_Lines *lines;
	Dwarf_Line *line;
	size_t nlines, i;
	Dwarf_Addr addr;
	int lineno, ret = 0;
	const char *src;
	Dwarf_Die die_mem;

	line_list__init(&lf->lr->line_list);
	if (dwarf_getsrclines(&lf->cu_die, &lines, &nlines) != 0) {
		pr_warning("No source lines found in this CU.\n");
		return -ENOENT;
	}

	/* Search probable lines on lines list */
	for (i = 0; i < nlines; i++) {
		line = dwarf_onesrcline(lines, i);
		if (dwarf_lineno(line, &lineno) != 0 ||
		    (lf->lno_s > lineno || lf->lno_e < lineno))
			continue;

		if (sp_die) {
			/* Address filtering 1: does sp_die include addr? */
			if (dwarf_lineaddr(line, &addr) != 0 ||
			    !dwarf_haspc(sp_die, addr))
				continue;

			/* Address filtering 2: No child include addr? */
			if (die_find_inlinefunc(sp_die, addr, &die_mem))
				continue;
		}

		/* TODO: Get fileno from line, but how? */
		src = dwarf_linesrc(line, NULL, NULL);
		if (strtailcmp(src, lf->fname) != 0)
			continue;

		ret = line_range_add_line(src, lineno, lf->lr);
		if (ret < 0)
			return ret;
	}

	/*
	 * Dwarf lines doesn't include function declarations. We have to
	 * check functions list or given function.
	 */
	if (sp_die) {
		src = dwarf_decl_file(sp_die);
		if (src && dwarf_decl_line(sp_die, &lineno) == 0 &&
		    (lf->lno_s <= lineno && lf->lno_e >= lineno))
			ret = line_range_add_line(src, lineno, lf->lr);
	} else
		ret = find_line_range_func_decl_lines(lf);

	/* Update status */
	if (ret >= 0)
		if (!list_empty(&lf->lr->line_list))
			ret = lf->found = 1;
		else
			ret = 0;	/* Lines are not found */
	else {
		free(lf->lr->path);
		lf->lr->path = NULL;
	}
	return ret;
}

static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
{
	struct dwarf_callback_param *param = data;

	param->retval = find_line_range_by_line(in_die, param->data);
	return DWARF_CB_ABORT;	/* No need to find other instances */
}

/* Search function from function name */
static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
{
	struct dwarf_callback_param *param = data;
	struct line_finder *lf = param->data;
	struct line_range *lr = lf->lr;

	if (dwarf_tag(sp_die) == DW_TAG_subprogram &&
	    die_compare_name(sp_die, lr->function) == 0) {
		lf->fname = dwarf_decl_file(sp_die);
		dwarf_decl_line(sp_die, &lr->offset);
		pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
		lf->lno_s = lr->offset + lr->start;
		if (lf->lno_s < 0)	/* Overflow */
			lf->lno_s = INT_MAX;
		lf->lno_e = lr->offset + lr->end;
		if (lf->lno_e < 0)	/* Overflow */
			lf->lno_e = INT_MAX;
		pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
		lr->start = lf->lno_s;
		lr->end = lf->lno_e;
		if (dwarf_func_inline(sp_die)) {
			struct dwarf_callback_param _param;
			_param.data = (void *)lf;
			_param.retval = 0;
			dwarf_func_inline_instances(sp_die,
						    line_range_inline_cb,
						    &_param);
			param->retval = _param.retval;
		} else
			param->retval = find_line_range_by_line(sp_die, lf);
		return DWARF_CB_ABORT;
	}
	return DWARF_CB_OK;
}

static int find_line_range_by_func(struct line_finder *lf)
{
	struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
	dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
	return param.retval;
}

int find_line_range(int fd, struct line_range *lr)
{
	struct line_finder lf = {.lr = lr, .found = 0};
	int ret = 0;
	Dwarf_Off off = 0, noff;
	size_t cuhl;
	Dwarf_Die *diep;
	Dwarf *dbg;

	dbg = dwarf_begin(fd, DWARF_C_READ);
	if (!dbg) {
		pr_warning("No dwarf info found in the vmlinux - "
			"please rebuild with CONFIG_DEBUG_INFO=y.\n");
		return -EBADF;
	}

	/* Loop on CUs (Compilation Unit) */
	while (!lf.found && ret >= 0) {
		if (dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL) != 0)
			break;

		/* Get the DIE(Debugging Information Entry) of this CU */
		diep = dwarf_offdie(dbg, off + cuhl, &lf.cu_die);
		if (!diep)
			continue;

		/* Check if target file is included. */
		if (lr->file)
			lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
		else
			lf.fname = 0;

		if (!lr->file || lf.fname) {
			if (lr->function)
				ret = find_line_range_by_func(&lf);
			else {
				lf.lno_s = lr->start;
				lf.lno_e = lr->end;
				ret = find_line_range_by_line(NULL, &lf);
			}
		}
		off = noff;
	}
	pr_debug("path: %lx\n", (unsigned long)lr->path);
	dwarf_end(dbg);

	return (ret < 0) ? ret : lf.found;
}