1	// SPDX-License-Identifier: GPL-2.0-or-later
2	/*
3	* probe-finder.c : C expression to kprobe event converter
4	*
5	* Written by Masami Hiramatsu <mhiramat@redhat.com>
6	*/
7
8	#include <inttypes.h>
9	#include <sys/utsname.h>
10	#include <sys/types.h>
11	#include <sys/stat.h>
12	#include <fcntl.h>
13	#include <errno.h>
14	#include <stdio.h>
15	#include <unistd.h>
16	#include <stdlib.h>
17	#include <string.h>
18	#include <stdarg.h>
19	#include <dwarf-regs.h>
20
21	#include <linux/bitops.h>
22	#include <linux/zalloc.h>
23	#include "event.h"
24	#include "dso.h"
25	#include "debug.h"
26	#include "debuginfo.h"
27	#include "intlist.h"
28	#include "strbuf.h"
29	#include "strlist.h"
30	#include "symbol.h"
31	#include "probe-finder.h"
32	#include "probe-file.h"
33	#include "string2.h"
34
35	/* Kprobe tracer basic type is up to u64 */
36	#define MAX_BASIC_TYPE_BITS 64
37
38	/*
39	* Probe finder related functions
40	*/
41
42	static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
43	{
44	struct probe_trace_arg_ref *ref;
45	ref = zalloc(sizeof(struct probe_trace_arg_ref));
46	if (ref != NULL)
47	ref->offset = offs;
48	return ref;
49	}
50
51	/*
52	* Convert a location into trace_arg.
53	* If tvar == NULL, this just checks variable can be converted.
54	* If fentry == true and vr_die is a parameter, do heuristic search
55	* for the location fuzzed by function entry mcount.
56	*/
57	static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
58	Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
59	unsigned int machine,
60	struct probe_trace_arg *tvar)
61	{
62	Dwarf_Attribute attr;
63	Dwarf_Addr tmp = 0;
64	Dwarf_Op *op;
65	size_t nops;
66	unsigned int regn;
67	Dwarf_Word offs = 0;
68	bool ref = false;
69	const char *regs;
70	int ret, ret2 = 0;
71
72	if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
73	goto static_var;
74
75	/* Constant value */
76	if (dwarf_attr(vr_die, DW_AT_const_value, &attr) &&
77	immediate_value_is_supported()) {
78	Dwarf_Sword snum;
79
80	if (!tvar)
81	return 0;
82
83	dwarf_formsdata(&attr, &snum);
84	ret = asprintf(&tvar->value, "\\%ld", (long)snum);
85
86	return ret < 0 ? -ENOMEM : 0;
87	}
88
89	/* TODO: handle more than 1 exprs */
90	if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
91	return -EINVAL; /* Broken DIE ? */
92	if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
93	ret = dwarf_entrypc(sp_die, &tmp);
94	if (ret)
95	return -ENOENT;
96
97	if (probe_conf.show_location_range &&
98	(dwarf_tag(vr_die) == DW_TAG_variable)) {
99	ret2 = -ERANGE;
100	} else if (addr != tmp ||
101	dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
102	return -ENOENT;
103	}
104
105	ret = dwarf_highpc(sp_die, &tmp);
106	if (ret)
107	return -ENOENT;
108	/*
109	* This is fuzzed by fentry mcount. We try to find the
110	* parameter location at the earliest address.
111	*/
112	for (addr += 1; addr <= tmp; addr++) {
113	if (dwarf_getlocation_addr(&attr, addr, &op,
114	&nops, 1) > 0)
115	goto found;
116	}
117	return -ENOENT;
118	}
119	found:
120	if (nops == 0)
121	/* TODO: Support const_value */
122	return -ENOENT;
123
124	if (op->atom == DW_OP_addr) {
125	static_var:
126	if (!tvar)
127	return ret2;
128	/* Static variables on memory (not stack), make @varname */
129	ret = strlen(dwarf_diename(vr_die));
130	tvar->value = zalloc(ret + 2);
131	if (tvar->value == NULL)
132	return -ENOMEM;
133	snprintf(buf: tvar->value, size: ret + 2, fmt: "@%s", dwarf_diename(vr_die));
134	tvar->ref = alloc_trace_arg_ref((long)offs);
135	if (tvar->ref == NULL)
136	return -ENOMEM;
137	return ret2;
138	}
139
140	/* If this is based on frame buffer, set the offset */
141	if (op->atom == DW_OP_fbreg) {
142	if (fb_ops == NULL)
143	return -ENOTSUP;
144	ref = true;
145	offs = op->number;
146	op = &fb_ops[0];
147	}
148
149	if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
150	regn = op->atom - DW_OP_breg0;
151	offs += op->number;
152	ref = true;
153	} else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
154	regn = op->atom - DW_OP_reg0;
155	} else if (op->atom == DW_OP_bregx) {
156	regn = op->number;
157	offs += op->number2;
158	ref = true;
159	} else if (op->atom == DW_OP_regx) {
160	regn = op->number;
161	} else {
162	pr_debug("DW_OP %x is not supported.\n", op->atom);
163	return -ENOTSUP;
164	}
165
166	if (!tvar)
167	return ret2;
168
169	regs = get_dwarf_regstr(regn, machine);
170	if (!regs) {
171	/* This should be a bug in DWARF or this tool */
172	pr_warning("Mapping for the register number %u "
173	"missing on this architecture.\n", regn);
174	return -ENOTSUP;
175	}
176
177	tvar->value = strdup(regs);
178	if (tvar->value == NULL)
179	return -ENOMEM;
180
181	if (ref) {
182	tvar->ref = alloc_trace_arg_ref((long)offs);
183	if (tvar->ref == NULL)
184	return -ENOMEM;
185	}
186	return ret2;
187	}
188
189	#define BYTES_TO_BITS(nb) ((nb) * BITS_PER_LONG / sizeof(long))
190
191	static int convert_variable_type(Dwarf_Die *vr_die,
192	struct probe_trace_arg *tvar,
193	const char *cast, bool user_access)
194	{
195	struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
196	Dwarf_Die type;
197	char buf[16];
198	char sbuf[STRERR_BUFSIZE];
199	int bsize, boffs, total;
200	int ret;
201	char prefix;
202
203	/* TODO: check all types */
204	if (cast && strcmp(cast, "string") != 0 && strcmp(cast, "ustring") &&
205	strcmp(cast, "x") != 0 &&
206	strcmp(cast, "s") != 0 && strcmp(cast, "u") != 0) {
207	/* Non string type is OK */
208	/* and respect signedness/hexadecimal cast */
209	tvar->type = strdup(cast);
210	return (tvar->type == NULL) ? -ENOMEM : 0;
211	}
212
213	bsize = dwarf_bitsize(vr_die);
214	if (bsize > 0) {
215	/* This is a bitfield */
216	boffs = dwarf_bitoffset(vr_die);
217	total = dwarf_bytesize(vr_die);
218	if (boffs < 0 || total < 0)
219	return -ENOENT;
220	ret = snprintf(buf, size: 16, fmt: "b%d@%d/%zd", bsize, boffs,
221	BYTES_TO_BITS(total));
222	goto formatted;
223	}
224
225	if (die_get_real_type(vr_die, &type) == NULL) {
226	pr_warning("Failed to get a type information of %s.\n",
227	dwarf_diename(vr_die));
228	return -ENOENT;
229	}
230
231	pr_debug("%s type is %s.\n",
232	dwarf_diename(vr_die), dwarf_diename(&type));
233
234	if (cast && (!strcmp(cast, "string") || !strcmp(cast, "ustring"))) {
235	/* String type */
236	ret = dwarf_tag(&type);
237	if (ret != DW_TAG_pointer_type &&
238	ret != DW_TAG_array_type) {
239	pr_warning("Failed to cast into string: "
240	"%s(%s) is not a pointer nor array.\n",
241	dwarf_diename(vr_die), dwarf_diename(&type));
242	return -EINVAL;
243	}
244	if (die_get_real_type(&type, &type) == NULL) {
245	pr_warning("Failed to get a type"
246	" information.\n");
247	return -ENOENT;
248	}
249	if (ret == DW_TAG_pointer_type) {
250	while (*ref_ptr)
251	ref_ptr = &(*ref_ptr)->next;
252	/* Add new reference with offset +0 */
253	*ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
254	if (*ref_ptr == NULL) {
255	pr_warning("Out of memory error\n");
256	return -ENOMEM;
257	}
258	(*ref_ptr)->user_access = user_access;
259	}
260	if (!die_compare_name(&type, "char") &&
261	!die_compare_name(&type, "unsigned char")) {
262	pr_warning("Failed to cast into string: "
263	"%s is not (unsigned) char *.\n",
264	dwarf_diename(vr_die));
265	return -EINVAL;
266	}
267	tvar->type = strdup(cast);
268	return (tvar->type == NULL) ? -ENOMEM : 0;
269	}
270
271	if (cast && (strcmp(cast, "u") == 0))
272	prefix = 'u';
273	else if (cast && (strcmp(cast, "s") == 0))
274	prefix = 's';
275	else if (cast && (strcmp(cast, "x") == 0) &&
276	probe_type_is_available(PROBE_TYPE_X))
277	prefix = 'x';
278	else
279	prefix = die_is_signed_type(&type) ? 's' :
280	probe_type_is_available(PROBE_TYPE_X) ? 'x' : 'u';
281
282	ret = dwarf_bytesize(&type);
283	if (ret <= 0)
284	/* No size ... try to use default type */
285	return 0;
286	ret = BYTES_TO_BITS(ret);
287
288	/* Check the bitwidth */
289	if (ret > MAX_BASIC_TYPE_BITS) {
290	pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
291	dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
292	ret = MAX_BASIC_TYPE_BITS;
293	}
294	ret = snprintf(buf, size: 16, fmt: "%c%d", prefix, ret);
295
296	formatted:
297	if (ret < 0 || ret >= 16) {
298	if (ret >= 16)
299	ret = -E2BIG;
300	pr_warning("Failed to convert variable type: %s\n",
301	str_error_r(-ret, sbuf, sizeof(sbuf)));
302	return ret;
303	}
304	tvar->type = strdup(buf);
305	if (tvar->type == NULL)
306	return -ENOMEM;
307	return 0;
308	}
309
310	static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
311	struct perf_probe_arg_field *field,
312	struct probe_trace_arg_ref **ref_ptr,
313	Dwarf_Die *die_mem, bool user_access)
314	{
315	struct probe_trace_arg_ref *ref = *ref_ptr;
316	Dwarf_Die type;
317	Dwarf_Word offs;
318	int ret, tag;
319
320	pr_debug("converting %s in %s\n", field->name, varname);
321	if (die_get_real_type(vr_die, &type) == NULL) {
322	pr_warning("Failed to get the type of %s.\n", varname);
323	return -ENOENT;
324	}
325	pr_debug2("Var real type: %s (%x)\n", dwarf_diename(&type),
326	(unsigned)dwarf_dieoffset(&type));
327	tag = dwarf_tag(&type);
328
329	if (field->name[0] == '[' &&
330	(tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
331	/* Save original type for next field or type */
332	memcpy(die_mem, &type, sizeof(*die_mem));
333	/* Get the type of this array */
334	if (die_get_real_type(&type, &type) == NULL) {
335	pr_warning("Failed to get the type of %s.\n", varname);
336	return -ENOENT;
337	}
338	pr_debug2("Array real type: %s (%x)\n", dwarf_diename(&type),
339	(unsigned)dwarf_dieoffset(&type));
340	if (tag == DW_TAG_pointer_type) {
341	ref = zalloc(sizeof(struct probe_trace_arg_ref));
342	if (ref == NULL)
343	return -ENOMEM;
344	if (*ref_ptr)
345	(*ref_ptr)->next = ref;
346	else
347	*ref_ptr = ref;
348	}
349	ref->offset += dwarf_bytesize(&type) * field->index;
350	ref->user_access = user_access;
351	goto next;
352	} else if (tag == DW_TAG_pointer_type) {
353	/* Check the pointer and dereference */
354	if (!field->ref) {
355	pr_err("Semantic error: %s must be referred by '->'\n",
356	field->name);
357	return -EINVAL;
358	}
359	/* Get the type pointed by this pointer */
360	if (die_get_real_type(&type, &type) == NULL) {
361	pr_warning("Failed to get the type of %s.\n", varname);
362	return -ENOENT;
363	}
364	/* Verify it is a data structure */
365	tag = dwarf_tag(&type);
366	if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
367	pr_warning("%s is not a data structure nor a union.\n",
368	varname);
369	return -EINVAL;
370	}
371
372	ref = zalloc(sizeof(struct probe_trace_arg_ref));
373	if (ref == NULL)
374	return -ENOMEM;
375	if (*ref_ptr)
376	(*ref_ptr)->next = ref;
377	else
378	*ref_ptr = ref;
379	} else {
380	/* Verify it is a data structure */
381	if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
382	pr_warning("%s is not a data structure nor a union.\n",
383	varname);
384	return -EINVAL;
385	}
386	if (field->name[0] == '[') {
387	pr_err("Semantic error: %s is not a pointer"
388	" nor array.\n", varname);
389	return -EINVAL;
390	}
391	/* While processing unnamed field, we don't care about this */
392	if (field->ref && dwarf_diename(vr_die)) {
393	pr_err("Semantic error: %s must be referred by '.'\n",
394	field->name);
395	return -EINVAL;
396	}
397	if (!ref) {
398	pr_warning("Structure on a register is not "
399	"supported yet.\n");
400	return -ENOTSUP;
401	}
402	}
403
404	if (die_find_member(&type, field->name, die_mem) == NULL) {
405	pr_warning("%s(type:%s) has no member %s.\n", varname,
406	dwarf_diename(&type), field->name);
407	return -EINVAL;
408	}
409
410	/* Get the offset of the field */
411	if (tag == DW_TAG_union_type) {
412	offs = 0;
413	} else {
414	ret = die_get_data_member_location(die_mem, &offs);
415	if (ret < 0) {
416	pr_warning("Failed to get the offset of %s.\n",
417	field->name);
418	return ret;
419	}
420	}
421	ref->offset += (long)offs;
422	ref->user_access = user_access;
423
424	/* If this member is unnamed, we need to reuse this field */
425	if (!dwarf_diename(die_mem))
426	return convert_variable_fields(die_mem, varname, field,
427	&ref, die_mem, user_access);
428
429	next:
430	/* Converting next field */
431	if (field->next)
432	return convert_variable_fields(die_mem, field->name,
433	field->next, &ref, die_mem, user_access);
434	else
435	return 0;
436	}
437
438	static void print_var_not_found(const char *varname)
439	{
440	pr_err("Failed to find the location of the '%s' variable at this address.\n"
441	" Perhaps it has been optimized out.\n"
442	" Use -V with the --range option to show '%s' location range.\n",
443	varname, varname);
444	}
445
446	/* Show a variables in kprobe event format */
447	static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
448	{
449	Dwarf_Die die_mem;
450	int ret;
451
452	pr_debug("Converting variable %s into trace event.\n",
453	dwarf_diename(vr_die));
454
455	ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
456	&pf->sp_die, pf->machine, pf->tvar);
457	if (ret == -ENOENT && pf->skip_empty_arg)
458	/* This can be found in other place. skip it */
459	return 0;
460	if (ret == -ENOENT || ret == -EINVAL) {
461	print_var_not_found(varname: pf->pvar->var);
462	} else if (ret == -ENOTSUP)
463	pr_err("Sorry, we don't support this variable location yet.\n");
464	else if (ret == 0 && pf->pvar->field) {
465	ret = convert_variable_fields(vr_die, pf->pvar->var,
466	pf->pvar->field, &pf->tvar->ref,
467	&die_mem, pf->pvar->user_access);
468	vr_die = &die_mem;
469	}
470	if (ret == 0)
471	ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type,
472	pf->pvar->user_access);
473	/* *expr will be cached in libdw. Don't free it. */
474	return ret;
475	}
476
477	/* Find a variable in a scope DIE */
478	static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
479	{
480	Dwarf_Die vr_die;
481	char *buf, *ptr;
482	int ret = 0;
483
484	/* Copy raw parameters */
485	if (!is_c_varname(name: pf->pvar->var))
486	return copy_to_probe_trace_arg(tvar: pf->tvar, pvar: pf->pvar);
487
488	if (pf->pvar->name)
489	pf->tvar->name = strdup(pf->pvar->name);
490	else {
491	buf = synthesize_perf_probe_arg(pa: pf->pvar);
492	if (!buf)
493	return -ENOMEM;
494	ptr = strchr(buf, ':'); /* Change type separator to _ */
495	if (ptr)
496	*ptr = '_';
497	pf->tvar->name = buf;
498	}
499	if (pf->tvar->name == NULL)
500	return -ENOMEM;
501
502	pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
503	/* Search child die for local variables and parameters. */
504	if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
505	/* Search again in global variables */
506	if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
507	0, &vr_die)) {
508	if (pf->skip_empty_arg)
509	return 0;
510	pr_warning("Failed to find '%s' in this function.\n",
511	pf->pvar->var);
512	ret = -ENOENT;
513	}
514	}
515	if (ret >= 0)
516	ret = convert_variable(&vr_die, pf);
517
518	return ret;
519	}
520
521	/* Convert subprogram DIE to trace point */
522	static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
523	Dwarf_Addr paddr, bool retprobe,
524	const char *function,
525	struct probe_trace_point *tp)
526	{
527	Dwarf_Addr eaddr;
528	GElf_Sym sym;
529	const char *symbol;
530
531	/* Verify the address is correct */
532	if (!dwarf_haspc(sp_die, paddr)) {
533	pr_warning("Specified offset is out of %s\n",
534	dwarf_diename(sp_die));
535	return -EINVAL;
536	}
537
538	if (dwarf_entrypc(sp_die, &eaddr) == 0) {
539	/* If the DIE has entrypc, use it. */
540	symbol = dwarf_diename(sp_die);
541	} else {
542	/* Try to get actual symbol name and address from symtab */
543	symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
544	eaddr = sym.st_value;
545	}
546	if (!symbol) {
547	pr_warning("Failed to find symbol at 0x%lx\n",
548	(unsigned long)paddr);
549	return -ENOENT;
550	}
551
552	tp->offset = (unsigned long)(paddr - eaddr);
553	tp->address = paddr;
554	tp->symbol = strdup(symbol);
555	if (!tp->symbol)
556	return -ENOMEM;
557
558	/* Return probe must be on the head of a subprogram */
559	if (retprobe) {
560	if (eaddr != paddr) {
561	pr_warning("Failed to find \"%s%%return\",\n"
562	" because %s is an inlined function and"
563	" has no return point.\n", function,
564	function);
565	return -EINVAL;
566	}
567	tp->retprobe = true;
568	}
569
570	return 0;
571	}
572
573	/* Call probe_finder callback with scope DIE */
574	static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
575	{
576	Dwarf_Attribute fb_attr;
577	Dwarf_Frame *frame = NULL;
578	size_t nops;
579	int ret;
580
581	if (!sc_die) {
582	pr_err("Caller must pass a scope DIE. Program error.\n");
583	return -EINVAL;
584	}
585
586	/* If not a real subprogram, find a real one */
587	if (!die_is_func_def(sc_die)) {
588	if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
589	if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
590	pr_warning("Ignoring tail call from %s\n",
591	dwarf_diename(&pf->sp_die));
592	return 0;
593	} else {
594	pr_warning("Failed to find probe point in any "
595	"functions.\n");
596	return -ENOENT;
597	}
598	}
599	} else
600	memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
601
602	/* Get the frame base attribute/ops from subprogram */
603	dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
604	ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
605	if (ret <= 0 || nops == 0) {
606	pf->fb_ops = NULL;
607	#ifdef HAVE_DWARF_CFI_SUPPORT
608	} else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
609	(pf->cfi_eh != NULL || pf->cfi_dbg != NULL)) {
610	if ((dwarf_cfi_addrframe(pf->cfi_eh, pf->addr, &frame) != 0 &&
611	(dwarf_cfi_addrframe(pf->cfi_dbg, pf->addr, &frame) != 0)) ||
612	dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
613	pr_warning("Failed to get call frame on 0x%jx\n",
614	(uintmax_t)pf->addr);
615	free(frame);
616	return -ENOENT;
617	}
618	#endif /* HAVE_DWARF_CFI_SUPPORT */
619	}
620
621	/* Call finder's callback handler */
622	ret = pf->callback(sc_die, pf);
623
624	/* Since *pf->fb_ops can be a part of frame. we should free it here. */
625	free(frame);
626	pf->fb_ops = NULL;
627
628	return ret;
629	}
630
631	struct find_scope_param {
632	const char *function;
633	const char *file;
634	int line;
635	int diff;
636	Dwarf_Die *die_mem;
637	bool found;
638	};
639
640	static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
641	{
642	struct find_scope_param *fsp = data;
643	const char *file;
644	int lno;
645
646	/* Skip if declared file name does not match */
647	if (fsp->file) {
648	file = die_get_decl_file(fn_die);
649	if (!file || strcmp(fsp->file, file) != 0)
650	return 0;
651	}
652	/* If the function name is given, that's what user expects */
653	if (fsp->function) {
654	if (die_match_name(fn_die, fsp->function)) {
655	memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
656	fsp->found = true;
657	return 1;
658	}
659	} else {
660	/* With the line number, find the nearest declared DIE */
661	dwarf_decl_line(fn_die, &lno);
662	if (lno < fsp->line && fsp->diff > fsp->line - lno) {
663	/* Keep a candidate and continue */
664	fsp->diff = fsp->line - lno;
665	memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
666	fsp->found = true;
667	}
668	}
669	return 0;
670	}
671
672	/* Return innermost DIE */
673	static int find_inner_scope_cb(Dwarf_Die *fn_die, void *data)
674	{
675	struct find_scope_param *fsp = data;
676
677	memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
678	fsp->found = true;
679	return 1;
680	}
681
682	/* Find an appropriate scope fits to given conditions */
683	static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
684	{
685	struct find_scope_param fsp = {
686	.function = pf->pev->point.function,
687	.file = pf->fname,
688	.line = pf->lno,
689	.diff = INT_MAX,
690	.die_mem = die_mem,
691	.found = false,
692	};
693	int ret;
694
695	ret = cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb,
696	&fsp);
697	if (!ret && !fsp.found)
698	cu_walk_functions_at(&pf->cu_die, pf->addr,
699	find_inner_scope_cb, &fsp);
700
701	return fsp.found ? die_mem : NULL;
702	}
703
704	static int verify_representive_line(struct probe_finder *pf, const char *fname,
705	int lineno, Dwarf_Addr addr)
706	{
707	const char *__fname, *__func = NULL;
708	Dwarf_Die die_mem;
709	int __lineno;
710
711	/* Verify line number and address by reverse search */
712	if (cu_find_lineinfo(&pf->cu_die, addr, &__fname, &__lineno) < 0)
713	return 0;
714
715	pr_debug2("Reversed line: %s:%d\n", __fname, __lineno);
716	if (strcmp(fname, __fname) || lineno == __lineno)
717	return 0;
718
719	pr_warning("This line is sharing the address with other lines.\n");
720
721	if (pf->pev->point.function) {
722	/* Find best match function name and lines */
723	pf->addr = addr;
724	if (find_best_scope(pf, &die_mem)
725	&& die_match_name(&die_mem, pf->pev->point.function)
726	&& dwarf_decl_line(&die_mem, &lineno) == 0) {
727	__func = dwarf_diename(&die_mem);
728	__lineno -= lineno;
729	}
730	}
731	pr_warning("Please try to probe at %s:%d instead.\n",
732	__func ? : __fname, __lineno);
733
734	return -ENOENT;
735	}
736
737	static int probe_point_line_walker(const char *fname, int lineno,
738	Dwarf_Addr addr, void *data)
739	{
740	struct probe_finder *pf = data;
741	Dwarf_Die *sc_die, die_mem;
742	int ret;
743
744	if (lineno != pf->lno || strtailcmp(s1: fname, s2: pf->fname) != 0)
745	return 0;
746
747	if (verify_representive_line(pf, fname, lineno, addr))
748	return -ENOENT;
749
750	pf->addr = addr;
751	sc_die = find_best_scope(pf, &die_mem);
752	if (!sc_die) {
753	pr_warning("Failed to find scope of probe point.\n");
754	return -ENOENT;
755	}
756
757	ret = call_probe_finder(sc_die, pf);
758
759	/* Continue if no error, because the line will be in inline function */
760	return ret < 0 ? ret : 0;
761	}
762
763	/* Find probe point from its line number */
764	static int find_probe_point_by_line(struct probe_finder *pf)
765	{
766	return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
767	}
768
769	/* Find lines which match lazy pattern */
770	static int find_lazy_match_lines(struct intlist *list,
771	const char *fname, const char *pat)
772	{
773	FILE *fp;
774	char *line = NULL;
775	size_t line_len;
776	ssize_t len;
777	int count = 0, linenum = 1;
778	char sbuf[STRERR_BUFSIZE];
779
780	fp = fopen(fname, "r");
781	if (!fp) {
782	pr_warning("Failed to open %s: %s\n", fname,
783	str_error_r(errno, sbuf, sizeof(sbuf)));
784	return -errno;
785	}
786
787	while ((len = getline(&line, &line_len, fp)) > 0) {
788
789	if (line[len - 1] == '\n')
790	line[len - 1] = '\0';
791
792	if (strlazymatch(str: line, pat)) {
793	intlist__add(ilist: list, i: linenum);
794	count++;
795	}
796	linenum++;
797	}
798
799	if (ferror(fp))
800	count = -errno;
801	free(line);
802	fclose(fp);
803
804	if (count == 0)
805	pr_debug("No matched lines found in %s.\n", fname);
806	return count;
807	}
808
809	static int probe_point_lazy_walker(const char *fname, int lineno,
810	Dwarf_Addr addr, void *data)
811	{
812	struct probe_finder *pf = data;
813	Dwarf_Die *sc_die, die_mem;
814	int ret;
815
816	if (!intlist__has_entry(ilist: pf->lcache, i: lineno) ||
817	strtailcmp(s1: fname, s2: pf->fname) != 0)
818	return 0;
819
820	pr_debug("Probe line found: line:%d addr:0x%llx\n",
821	lineno, (unsigned long long)addr);
822	pf->addr = addr;
823	pf->lno = lineno;
824	sc_die = find_best_scope(pf, &die_mem);
825	if (!sc_die) {
826	pr_warning("Failed to find scope of probe point.\n");
827	return -ENOENT;
828	}
829
830	ret = call_probe_finder(sc_die, pf);
831
832	/*
833	* Continue if no error, because the lazy pattern will match
834	* to other lines
835	*/
836	return ret < 0 ? ret : 0;
837	}
838
839	/* Find probe points from lazy pattern */
840	static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
841	{
842	struct build_id bid;
843	char sbuild_id[SBUILD_ID_SIZE] = "";
844	int ret = 0;
845	char *fpath;
846
847	if (intlist__empty(ilist: pf->lcache)) {
848	const char *comp_dir;
849
850	comp_dir = cu_get_comp_dir(&pf->cu_die);
851	if (pf->dbg->build_id) {
852	build_id__init(bid: &bid, data: pf->dbg->build_id, BUILD_ID_SIZE);
853	build_id__sprintf(build_id: &bid, bf: sbuild_id);
854	}
855	ret = find_source_path(pf->fname, sbuild_id, comp_dir, &fpath);
856	if (ret < 0) {
857	pr_warning("Failed to find source file path.\n");
858	return ret;
859	}
860
861	/* Matching lazy line pattern */
862	ret = find_lazy_match_lines(list: pf->lcache, fname: fpath,
863	pat: pf->pev->point.lazy_line);
864	free(fpath);
865	if (ret <= 0)
866	return ret;
867	}
868
869	return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
870	}
871
872	static void skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf)
873	{
874	struct perf_probe_point *pp = &pf->pev->point;
875
876	/* Not uprobe? */
877	if (!pf->pev->uprobes)
878	return;
879
880	/* Compiled with optimization? */
881	if (die_is_optimized_target(&pf->cu_die))
882	return;
883
884	/* Don't know entrypc? */
885	if (!pf->addr)
886	return;
887
888	/* Only FUNC and FUNC@SRC are eligible. */
889	if (!pp->function || pp->line || pp->retprobe || pp->lazy_line ||
890	pp->offset || pp->abs_address)
891	return;
892
893	/* Not interested in func parameter? */
894	if (!perf_probe_with_var(pev: pf->pev))
895	return;
896
897	pr_info("Target program is compiled without optimization. Skipping prologue.\n"
898	"Probe on address 0x%" PRIx64 " to force probing at the function entry.\n\n",
899	pf->addr);
900
901	die_skip_prologue(sp_die, &pf->cu_die, &pf->addr);
902	}
903
904	static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
905	{
906	struct probe_finder *pf = data;
907	struct perf_probe_point *pp = &pf->pev->point;
908	Dwarf_Addr addr;
909	int ret;
910
911	if (pp->lazy_line)
912	ret = find_probe_point_lazy(in_die, pf);
913	else {
914	/* Get probe address */
915	if (die_entrypc(in_die, &addr) != 0) {
916	pr_warning("Failed to get entry address of %s.\n",
917	dwarf_diename(in_die));
918	return -ENOENT;
919	}
920	if (addr == 0) {
921	pr_debug("%s has no valid entry address. skipped.\n",
922	dwarf_diename(in_die));
923	return -ENOENT;
924	}
925	pf->addr = addr;
926	pf->addr += pp->offset;
927	pr_debug("found inline addr: 0x%jx\n",
928	(uintmax_t)pf->addr);
929
930	ret = call_probe_finder(in_die, pf);
931	}
932
933	return ret;
934	}
935
936	/* Callback parameter with return value for libdw */
937	struct dwarf_callback_param {
938	void *data;
939	int retval;
940	};
941
942	/* Search function from function name */
943	static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
944	{
945	struct dwarf_callback_param *param = data;
946	struct probe_finder *pf = param->data;
947	struct perf_probe_point *pp = &pf->pev->point;
948	const char *fname;
949
950	/* Check tag and diename */
951	if (!die_is_func_def(sp_die) ||
952	!die_match_name(sp_die, pp->function))
953	return DWARF_CB_OK;
954
955	/* Check declared file */
956	fname = die_get_decl_file(sp_die);
957	if (!fname) {
958	pr_warning("A function DIE doesn't have decl_line. Maybe broken DWARF?\n");
959	return DWARF_CB_OK;
960	}
961	if (pp->file && fname && strtailcmp(pp->file, fname))
962	return DWARF_CB_OK;
963
964	pr_debug("Matched function: %s [%lx]\n", dwarf_diename(sp_die),
965	(unsigned long)dwarf_dieoffset(sp_die));
966	pf->fname = fname;
967	if (pp->line) { /* Function relative line */
968	dwarf_decl_line(sp_die, &pf->lno);
969	pf->lno += pp->line;
970	param->retval = find_probe_point_by_line(pf);
971	} else if (die_is_func_instance(sp_die)) {
972	/* Instances always have the entry address */
973	die_entrypc(sp_die, &pf->addr);
974	/* But in some case the entry address is 0 */
975	if (pf->addr == 0) {
976	pr_debug("%s has no entry PC. Skipped\n",
977	dwarf_diename(sp_die));
978	param->retval = 0;
979	/* Real function */
980	} else if (pp->lazy_line)
981	param->retval = find_probe_point_lazy(sp_die, pf);
982	else {
983	skip_prologue(sp_die, pf);
984	pf->addr += pp->offset;
985	/* TODO: Check the address in this function */
986	param->retval = call_probe_finder(sp_die, pf);
987	}
988	} else if (!probe_conf.no_inlines) {
989	/* Inlined function: search instances */
990	param->retval = die_walk_instances(sp_die,
991	probe_point_inline_cb, (void *)pf);
992	/* This could be a non-existed inline definition */
993	if (param->retval == -ENOENT)
994	param->retval = 0;
995	}
996
997	/* We need to find other candidates */
998	if (strisglob(str: pp->function) && param->retval >= 0) {
999	param->retval = 0; /* We have to clear the result */
1000	return DWARF_CB_OK;
1001	}
1002
1003	return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1004	}
1005
1006	static int find_probe_point_by_func(struct probe_finder *pf)
1007	{
1008	struct dwarf_callback_param _param = {.data = (void *)pf,
1009	.retval = 0};
1010	dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1011	return _param.retval;
1012	}
1013
1014	struct pubname_callback_param {
1015	char *function;
1016	char *file;
1017	Dwarf_Die *cu_die;
1018	Dwarf_Die *sp_die;
1019	int found;
1020	};
1021
1022	static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1023	{
1024	struct pubname_callback_param *param = data;
1025	const char *fname;
1026
1027	if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1028	if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1029	return DWARF_CB_OK;
1030
1031	if (die_match_name(param->sp_die, param->function)) {
1032	if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1033	return DWARF_CB_OK;
1034
1035	if (param->file) {
1036	fname = die_get_decl_file(param->sp_die);
1037	if (!fname || strtailcmp(param->file, fname))
1038	return DWARF_CB_OK;
1039	}
1040
1041	param->found = 1;
1042	return DWARF_CB_ABORT;
1043	}
1044	}
1045
1046	return DWARF_CB_OK;
1047	}
1048
1049	static int debuginfo__find_probe_location(struct debuginfo *dbg,
1050	struct probe_finder *pf)
1051	{
1052	struct perf_probe_point *pp = &pf->pev->point;
1053	Dwarf_Off off, noff;
1054	size_t cuhl;
1055	Dwarf_Die *diep;
1056	int ret = 0;
1057
1058	off = 0;
1059	pf->lcache = intlist__new(NULL);
1060	if (!pf->lcache)
1061	return -ENOMEM;
1062
1063	/* Fastpath: lookup by function name from .debug_pubnames section */
1064	if (pp->function && !strisglob(str: pp->function)) {
1065	struct pubname_callback_param pubname_param = {
1066	.function = pp->function,
1067	.file = pp->file,
1068	.cu_die = &pf->cu_die,
1069	.sp_die = &pf->sp_die,
1070	.found = 0,
1071	};
1072	struct dwarf_callback_param probe_param = {
1073	.data = pf,
1074	};
1075
1076	dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1077	&pubname_param, 0);
1078	if (pubname_param.found) {
1079	ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1080	if (ret)
1081	goto found;
1082	}
1083	}
1084
1085	/* Loop on CUs (Compilation Unit) */
1086	while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1087	/* Get the DIE(Debugging Information Entry) of this CU */
1088	diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1089	if (!diep) {
1090	off = noff;
1091	continue;
1092	}
1093
1094	/* Check if target file is included. */
1095	if (pp->file)
1096	pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1097	else
1098	pf->fname = NULL;
1099
1100	if (!pp->file || pf->fname) {
1101	if (pp->function)
1102	ret = find_probe_point_by_func(pf);
1103	else if (pp->lazy_line)
1104	ret = find_probe_point_lazy(&pf->cu_die, pf);
1105	else {
1106	pf->lno = pp->line;
1107	ret = find_probe_point_by_line(pf);
1108	}
1109	if (ret < 0)
1110	break;
1111	}
1112	off = noff;
1113	}
1114
1115	found:
1116	intlist__delete(ilist: pf->lcache);
1117	pf->lcache = NULL;
1118
1119	return ret;
1120	}
1121
1122	/* Find probe points from debuginfo */
1123	static int debuginfo__find_probes(struct debuginfo *dbg,
1124	struct probe_finder *pf)
1125	{
1126	int ret = 0;
1127	Elf *elf;
1128	GElf_Ehdr ehdr;
1129
1130	if (pf->cfi_eh || pf->cfi_dbg)
1131	return debuginfo__find_probe_location(dbg, pf);
1132
1133	/* Get the call frame information from this dwarf */
1134	elf = dwarf_getelf(dbg->dbg);
1135	if (elf == NULL)
1136	return -EINVAL;
1137
1138	if (gelf_getehdr(elf, &ehdr) == NULL)
1139	return -EINVAL;
1140
1141	pf->machine = ehdr.e_machine;
1142
1143	#ifdef HAVE_DWARF_CFI_SUPPORT
1144	do {
1145	GElf_Shdr shdr;
1146
1147	if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1148	shdr.sh_type == SHT_PROGBITS)
1149	pf->cfi_eh = dwarf_getcfi_elf(elf);
1150
1151	pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
1152	} while (0);
1153	#endif /* HAVE_DWARF_CFI_SUPPORT */
1154
1155	ret = debuginfo__find_probe_location(dbg, pf);
1156	return ret;
1157	}
1158
1159	struct local_vars_finder {
1160	struct probe_finder *pf;
1161	struct perf_probe_arg *args;
1162	bool vars;
1163	int max_args;
1164	int nargs;
1165	int ret;
1166	};
1167
1168	/* Collect available variables in this scope */
1169	static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1170	{
1171	struct local_vars_finder *vf = data;
1172	struct probe_finder *pf = vf->pf;
1173	int tag;
1174
1175	tag = dwarf_tag(die_mem);
1176	if (tag == DW_TAG_formal_parameter ||
1177	(tag == DW_TAG_variable && vf->vars)) {
1178	if (convert_variable_location(die_mem, vf->pf->addr,
1179	vf->pf->fb_ops, &pf->sp_die,
1180	pf->machine, NULL) == 0) {
1181	vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1182	if (vf->args[vf->nargs].var == NULL) {
1183	vf->ret = -ENOMEM;
1184	return DIE_FIND_CB_END;
1185	}
1186	pr_debug(" %s", vf->args[vf->nargs].var);
1187	vf->nargs++;
1188	}
1189	}
1190
1191	if (dwarf_haspc(die_mem, vf->pf->addr))
1192	return DIE_FIND_CB_CONTINUE;
1193	else
1194	return DIE_FIND_CB_SIBLING;
1195	}
1196
1197	static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1198	struct perf_probe_arg *args)
1199	{
1200	Dwarf_Die die_mem;
1201	int i;
1202	int n = 0;
1203	struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1204	.max_args = MAX_PROBE_ARGS, .ret = 0};
1205
1206	for (i = 0; i < pf->pev->nargs; i++) {
1207	/* var never be NULL */
1208	if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1209	vf.vars = true;
1210	else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1211	/* Copy normal argument */
1212	args[n] = pf->pev->args[i];
1213	n++;
1214	continue;
1215	}
1216	pr_debug("Expanding %s into:", pf->pev->args[i].var);
1217	vf.nargs = n;
1218	/* Special local variables */
1219	die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1220	&die_mem);
1221	pr_debug(" (%d)\n", vf.nargs - n);
1222	if (vf.ret < 0)
1223	return vf.ret;
1224	n = vf.nargs;
1225	}
1226	return n;
1227	}
1228
1229	static bool trace_event_finder_overlap(struct trace_event_finder *tf)
1230	{
1231	int i;
1232
1233	for (i = 0; i < tf->ntevs; i++) {
1234	if (tf->pf.addr == tf->tevs[i].point.address)
1235	return true;
1236	}
1237	return false;
1238	}
1239
1240	/* Add a found probe point into trace event list */
1241	static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1242	{
1243	struct trace_event_finder *tf =
1244	container_of(pf, struct trace_event_finder, pf);
1245	struct perf_probe_point *pp = &pf->pev->point;
1246	struct probe_trace_event *tev;
1247	struct perf_probe_arg *args = NULL;
1248	int ret, i;
1249
1250	/*
1251	* For some reason (e.g. different column assigned to same address)
1252	* This callback can be called with the address which already passed.
1253	* Ignore it first.
1254	*/
1255	if (trace_event_finder_overlap(tf))
1256	return 0;
1257
1258	/* Check number of tevs */
1259	if (tf->ntevs == tf->max_tevs) {
1260	pr_warning("Too many( > %d) probe point found.\n",
1261	tf->max_tevs);
1262	return -ERANGE;
1263	}
1264	tev = &tf->tevs[tf->ntevs++];
1265
1266	/* Trace point should be converted from subprogram DIE */
1267	ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1268	pp->retprobe, pp->function, &tev->point);
1269	if (ret < 0)
1270	goto end;
1271
1272	tev->point.realname = strdup(dwarf_diename(sc_die));
1273	if (!tev->point.realname) {
1274	ret = -ENOMEM;
1275	goto end;
1276	}
1277
1278	pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1279	tev->point.offset);
1280
1281	/* Expand special probe argument if exist */
1282	args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1283	if (args == NULL) {
1284	ret = -ENOMEM;
1285	goto end;
1286	}
1287
1288	ret = expand_probe_args(sc_die, pf, args);
1289	if (ret < 0)
1290	goto end;
1291
1292	tev->nargs = ret;
1293	tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1294	if (tev->args == NULL) {
1295	ret = -ENOMEM;
1296	goto end;
1297	}
1298
1299	/* Find each argument */
1300	for (i = 0; i < tev->nargs; i++) {
1301	pf->pvar = &args[i];
1302	pf->tvar = &tev->args[i];
1303	/* Variable should be found from scope DIE */
1304	ret = find_variable(sc_die, pf);
1305	if (ret != 0)
1306	break;
1307	}
1308
1309	end:
1310	if (ret) {
1311	clear_probe_trace_event(tev);
1312	tf->ntevs--;
1313	}
1314	free(args);
1315	return ret;
1316	}
1317
1318	static int fill_empty_trace_arg(struct perf_probe_event *pev,
1319	struct probe_trace_event *tevs, int ntevs)
1320	{
1321	char **valp;
1322	char *type;
1323	int i, j, ret;
1324
1325	if (!ntevs)
1326	return -ENOENT;
1327
1328	for (i = 0; i < pev->nargs; i++) {
1329	type = NULL;
1330	for (j = 0; j < ntevs; j++) {
1331	if (tevs[j].args[i].value) {
1332	type = tevs[j].args[i].type;
1333	break;
1334	}
1335	}
1336	if (j == ntevs) {
1337	print_var_not_found(varname: pev->args[i].var);
1338	return -ENOENT;
1339	}
1340	for (j = 0; j < ntevs; j++) {
1341	valp = &tevs[j].args[i].value;
1342	if (*valp)
1343	continue;
1344
1345	ret = asprintf(valp, "\\%lx", probe_conf.magic_num);
1346	if (ret < 0)
1347	return -ENOMEM;
1348	/* Note that type can be NULL */
1349	if (type) {
1350	tevs[j].args[i].type = strdup(type);
1351	if (!tevs[j].args[i].type)
1352	return -ENOMEM;
1353	}
1354	}
1355	}
1356	return 0;
1357	}
1358
1359	/* Find probe_trace_events specified by perf_probe_event from debuginfo */
1360	int debuginfo__find_trace_events(struct debuginfo *dbg,
1361	struct perf_probe_event *pev,
1362	struct probe_trace_event **tevs)
1363	{
1364	struct trace_event_finder tf = {
1365	.pf = {.pev = pev, .dbg = dbg, .callback = add_probe_trace_event},
1366	.max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1367	int ret, i;
1368
1369	/* Allocate result tevs array */
1370	*tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1371	if (*tevs == NULL)
1372	return -ENOMEM;
1373
1374	tf.tevs = *tevs;
1375	tf.ntevs = 0;
1376
1377	if (pev->nargs != 0 && immediate_value_is_supported())
1378	tf.pf.skip_empty_arg = true;
1379
1380	ret = debuginfo__find_probes(dbg, pf: &tf.pf);
1381	if (ret >= 0 && tf.pf.skip_empty_arg)
1382	ret = fill_empty_trace_arg(pev, tevs: tf.tevs, ntevs: tf.ntevs);
1383
1384	if (ret < 0 || tf.ntevs == 0) {
1385	for (i = 0; i < tf.ntevs; i++)
1386	clear_probe_trace_event(tev: &tf.tevs[i]);
1387	zfree(tevs);
1388	return ret;
1389	}
1390
1391	return (ret < 0) ? ret : tf.ntevs;
1392	}
1393
1394	/* Collect available variables in this scope */
1395	static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1396	{
1397	struct available_var_finder *af = data;
1398	struct variable_list *vl;
1399	struct strbuf buf = STRBUF_INIT;
1400	int tag, ret;
1401
1402	vl = &af->vls[af->nvls - 1];
1403
1404	tag = dwarf_tag(die_mem);
1405	if (tag == DW_TAG_formal_parameter ||
1406	tag == DW_TAG_variable) {
1407	ret = convert_variable_location(die_mem, af->pf.addr,
1408	af->pf.fb_ops, &af->pf.sp_die,
1409	af->pf.machine, NULL);
1410	if (ret == 0 || ret == -ERANGE) {
1411	int ret2;
1412	bool externs = !af->child;
1413
1414	if (strbuf_init(buf: &buf, hint: 64) < 0)
1415	goto error;
1416
1417	if (probe_conf.show_location_range) {
1418	if (!externs)
1419	ret2 = strbuf_add(buf: &buf,
1420	ret ? "[INV]\t" : "[VAL]\t", 6);
1421	else
1422	ret2 = strbuf_add(buf: &buf, "[EXT]\t", 6);
1423	if (ret2)
1424	goto error;
1425	}
1426
1427	ret2 = die_get_varname(die_mem, &buf);
1428
1429	if (!ret2 && probe_conf.show_location_range &&
1430	!externs) {
1431	if (strbuf_addch(sb: &buf, c: '\t') < 0)
1432	goto error;
1433	ret2 = die_get_var_range(&af->pf.sp_die,
1434	die_mem, &buf);
1435	}
1436
1437	pr_debug("Add new var: %s\n", buf.buf);
1438	if (ret2 == 0) {
1439	strlist__add(slist: vl->vars,
1440	str: strbuf_detach(buf: &buf, NULL));
1441	}
1442	strbuf_release(buf: &buf);
1443	}
1444	}
1445
1446	if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1447	return DIE_FIND_CB_CONTINUE;
1448	else
1449	return DIE_FIND_CB_SIBLING;
1450	error:
1451	strbuf_release(buf: &buf);
1452	pr_debug("Error in strbuf\n");
1453	return DIE_FIND_CB_END;
1454	}
1455
1456	static bool available_var_finder_overlap(struct available_var_finder *af)
1457	{
1458	int i;
1459
1460	for (i = 0; i < af->nvls; i++) {
1461	if (af->pf.addr == af->vls[i].point.address)
1462	return true;
1463	}
1464	return false;
1465
1466	}
1467
1468	/* Add a found vars into available variables list */
1469	static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1470	{
1471	struct available_var_finder *af =
1472	container_of(pf, struct available_var_finder, pf);
1473	struct perf_probe_point *pp = &pf->pev->point;
1474	struct variable_list *vl;
1475	Dwarf_Die die_mem;
1476	int ret;
1477
1478	/*
1479	* For some reason (e.g. different column assigned to same address),
1480	* this callback can be called with the address which already passed.
1481	* Ignore it first.
1482	*/
1483	if (available_var_finder_overlap(af))
1484	return 0;
1485
1486	/* Check number of tevs */
1487	if (af->nvls == af->max_vls) {
1488	pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1489	return -ERANGE;
1490	}
1491	vl = &af->vls[af->nvls++];
1492
1493	/* Trace point should be converted from subprogram DIE */
1494	ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1495	pp->retprobe, pp->function, &vl->point);
1496	if (ret < 0)
1497	return ret;
1498
1499	pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1500	vl->point.offset);
1501
1502	/* Find local variables */
1503	vl->vars = strlist__new(NULL, NULL);
1504	if (vl->vars == NULL)
1505	return -ENOMEM;
1506	af->child = true;
1507	die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1508
1509	/* Find external variables */
1510	if (!probe_conf.show_ext_vars)
1511	goto out;
1512	/* Don't need to search child DIE for external vars. */
1513	af->child = false;
1514	die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1515
1516	out:
1517	if (strlist__empty(slist: vl->vars)) {
1518	strlist__delete(slist: vl->vars);
1519	vl->vars = NULL;
1520	}
1521
1522	return ret;
1523	}
1524
1525	/*
1526	* Find available variables at given probe point
1527	* Return the number of found probe points. Return 0 if there is no
1528	* matched probe point. Return <0 if an error occurs.
1529	*/
1530	int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1531	struct perf_probe_event *pev,
1532	struct variable_list **vls)
1533	{
1534	struct available_var_finder af = {
1535	.pf = {.pev = pev, .dbg = dbg, .callback = add_available_vars},
1536	.mod = dbg->mod,
1537	.max_vls = probe_conf.max_probes};
1538	int ret;
1539
1540	/* Allocate result vls array */
1541	*vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1542	if (*vls == NULL)
1543	return -ENOMEM;
1544
1545	af.vls = *vls;
1546	af.nvls = 0;
1547
1548	ret = debuginfo__find_probes(dbg, pf: &af.pf);
1549	if (ret < 0) {
1550	/* Free vlist for error */
1551	while (af.nvls--) {
1552	zfree(&af.vls[af.nvls].point.symbol);
1553	strlist__delete(slist: af.vls[af.nvls].vars);
1554	}
1555	zfree(vls);
1556	return ret;
1557	}
1558
1559	return (ret < 0) ? ret : af.nvls;
1560	}
1561
1562	/* Reverse search */
1563	int debuginfo__find_probe_point(struct debuginfo *dbg, u64 addr,
1564	struct perf_probe_point *ppt)
1565	{
1566	Dwarf_Die cudie, spdie, indie;
1567	Dwarf_Addr _addr = 0, baseaddr = 0;
1568	const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1569	int baseline = 0, lineno = 0, ret = 0;
1570
1571	/* We always need to relocate the address for aranges */
1572	if (debuginfo__get_text_offset(dbg, &baseaddr, false) == 0)
1573	addr += baseaddr;
1574	/* Find cu die */
1575	if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1576	pr_warning("Failed to find debug information for address %#" PRIx64 "\n",
1577	addr);
1578	ret = -EINVAL;
1579	goto end;
1580	}
1581
1582	/* Find a corresponding line (filename and lineno) */
1583	cu_find_lineinfo(&cudie, (Dwarf_Addr)addr, &fname, &lineno);
1584	/* Don't care whether it failed or not */
1585
1586	/* Find a corresponding function (name, baseline and baseaddr) */
1587	if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1588	/* Get function entry information */
1589	func = basefunc = dwarf_diename(&spdie);
1590	if (!func ||
1591	die_entrypc(&spdie, &baseaddr) != 0 ||
1592	dwarf_decl_line(&spdie, &baseline) != 0) {
1593	lineno = 0;
1594	goto post;
1595	}
1596
1597	fname = die_get_decl_file(&spdie);
1598	if (addr == baseaddr) {
1599	/* Function entry - Relative line number is 0 */
1600	lineno = baseline;
1601	goto post;
1602	}
1603
1604	/* Track down the inline functions step by step */
1605	while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1606	&indie)) {
1607	/* There is an inline function */
1608	if (die_entrypc(&indie, &_addr) == 0 &&
1609	_addr == addr) {
1610	/*
1611	* addr is at an inline function entry.
1612	* In this case, lineno should be the call-site
1613	* line number. (overwrite lineinfo)
1614	*/
1615	lineno = die_get_call_lineno(&indie);
1616	fname = die_get_call_file(&indie);
1617	break;
1618	} else {
1619	/*
1620	* addr is in an inline function body.
1621	* Since lineno points one of the lines
1622	* of the inline function, baseline should
1623	* be the entry line of the inline function.
1624	*/
1625	tmp = dwarf_diename(&indie);
1626	if (!tmp ||
1627	dwarf_decl_line(&indie, &baseline) != 0)
1628	break;
1629	func = tmp;
1630	spdie = indie;
1631	}
1632	}
1633	/* Verify the lineno and baseline are in a same file */
1634	tmp = die_get_decl_file(&spdie);
1635	if (!tmp || (fname && strcmp(tmp, fname) != 0))
1636	lineno = 0;
1637	}
1638
1639	post:
1640	/* Make a relative line number or an offset */
1641	if (lineno)
1642	ppt->line = lineno - baseline;
1643	else if (basefunc) {
1644	ppt->offset = addr - baseaddr;
1645	func = basefunc;
1646	}
1647
1648	/* Duplicate strings */
1649	if (func) {
1650	ppt->function = strdup(func);
1651	if (ppt->function == NULL) {
1652	ret = -ENOMEM;
1653	goto end;
1654	}
1655	}
1656	if (fname) {
1657	ppt->file = strdup(fname);
1658	if (ppt->file == NULL) {
1659	zfree(&ppt->function);
1660	ret = -ENOMEM;
1661	goto end;
1662	}
1663	}
1664	end:
1665	if (ret == 0 && (fname || func))
1666	ret = 1; /* Found a point */
1667	return ret;
1668	}
1669
1670	/* Add a line and store the src path */
1671	static int line_range_add_line(const char *src, unsigned int lineno,
1672	struct line_range *lr)
1673	{
1674	/* Copy source path */
1675	if (!lr->path) {
1676	lr->path = strdup(src);
1677	if (lr->path == NULL)
1678	return -ENOMEM;
1679	}
1680	return intlist__add(ilist: lr->line_list, i: lineno);
1681	}
1682
1683	static int line_range_walk_cb(const char *fname, int lineno,
1684	Dwarf_Addr addr, void *data)
1685	{
1686	struct line_finder *lf = data;
1687	const char *__fname;
1688	int __lineno;
1689	int err;
1690
1691	if ((strtailcmp(s1: fname, s2: lf->fname) != 0) ||
1692	(lf->lno_s > lineno || lf->lno_e < lineno))
1693	return 0;
1694
1695	/* Make sure this line can be reversible */
1696	if (cu_find_lineinfo(&lf->cu_die, addr, &__fname, &__lineno) > 0
1697	&& (lineno != __lineno || strcmp(fname, __fname)))
1698	return 0;
1699
1700	err = line_range_add_line(src: fname, lineno, lr: lf->lr);
1701	if (err < 0 && err != -EEXIST)
1702	return err;
1703
1704	return 0;
1705	}
1706
1707	/* Find line range from its line number */
1708	static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1709	{
1710	int ret;
1711
1712	ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1713
1714	/* Update status */
1715	if (ret >= 0)
1716	if (!intlist__empty(ilist: lf->lr->line_list))
1717	ret = lf->found = 1;
1718	else
1719	ret = 0; /* Lines are not found */
1720	else {
1721	zfree(&lf->lr->path);
1722	}
1723	return ret;
1724	}
1725
1726	static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1727	{
1728	int ret = find_line_range_by_line(in_die, data);
1729
1730	/*
1731	* We have to check all instances of inlined function, because
1732	* some execution paths can be optimized out depends on the
1733	* function argument of instances. However, if an error occurs,
1734	* it should be handled by the caller.
1735	*/
1736	return ret < 0 ? ret : 0;
1737	}
1738
1739	/* Search function definition from function name */
1740	static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1741	{
1742	struct dwarf_callback_param *param = data;
1743	struct line_finder *lf = param->data;
1744	struct line_range *lr = lf->lr;
1745	const char *fname;
1746
1747	/* Check declared file */
1748	if (lr->file) {
1749	fname = die_get_decl_file(sp_die);
1750	if (!fname || strtailcmp(lr->file, fname))
1751	return DWARF_CB_OK;
1752	}
1753
1754	if (die_match_name(sp_die, lr->function) && die_is_func_def(sp_die)) {
1755	lf->fname = die_get_decl_file(sp_die);
1756	dwarf_decl_line(sp_die, &lr->offset);
1757	pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1758	lf->lno_s = lr->offset + lr->start;
1759	if (lf->lno_s < 0) /* Overflow */
1760	lf->lno_s = INT_MAX;
1761	lf->lno_e = lr->offset + lr->end;
1762	if (lf->lno_e < 0) /* Overflow */
1763	lf->lno_e = INT_MAX;
1764	pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1765	lr->start = lf->lno_s;
1766	lr->end = lf->lno_e;
1767	if (!die_is_func_instance(sp_die))
1768	param->retval = die_walk_instances(sp_die,
1769	line_range_inline_cb, lf);
1770	else
1771	param->retval = find_line_range_by_line(sp_die, lf);
1772	return DWARF_CB_ABORT;
1773	}
1774	return DWARF_CB_OK;
1775	}
1776
1777	static int find_line_range_by_func(struct line_finder *lf)
1778	{
1779	struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1780	dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1781	return param.retval;
1782	}
1783
1784	int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1785	{
1786	struct line_finder lf = {.lr = lr, .found = 0};
1787	int ret = 0;
1788	Dwarf_Off off = 0, noff;
1789	size_t cuhl;
1790	Dwarf_Die *diep;
1791	const char *comp_dir;
1792
1793	/* Fastpath: lookup by function name from .debug_pubnames section */
1794	if (lr->function) {
1795	struct pubname_callback_param pubname_param = {
1796	.function = lr->function, .file = lr->file,
1797	.cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1798	struct dwarf_callback_param line_range_param = {
1799	.data = (void *)&lf, .retval = 0};
1800
1801	dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1802	&pubname_param, 0);
1803	if (pubname_param.found) {
1804	line_range_search_cb(&lf.sp_die, &line_range_param);
1805	if (lf.found)
1806	goto found;
1807	}
1808	}
1809
1810	/* Loop on CUs (Compilation Unit) */
1811	while (!lf.found && ret >= 0) {
1812	if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1813	NULL, NULL, NULL) != 0)
1814	break;
1815
1816	/* Get the DIE(Debugging Information Entry) of this CU */
1817	diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1818	if (!diep) {
1819	off = noff;
1820	continue;
1821	}
1822
1823	/* Check if target file is included. */
1824	if (lr->file)
1825	lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1826	else
1827	lf.fname = 0;
1828
1829	if (!lr->file || lf.fname) {
1830	if (lr->function)
1831	ret = find_line_range_by_func(lf: &lf);
1832	else {
1833	lf.lno_s = lr->start;
1834	lf.lno_e = lr->end;
1835	ret = find_line_range_by_line(NULL, &lf);
1836	}
1837	}
1838	off = noff;
1839	}
1840
1841	found:
1842	/* Store comp_dir */
1843	if (lf.found) {
1844	comp_dir = cu_get_comp_dir(&lf.cu_die);
1845	if (comp_dir) {
1846	lr->comp_dir = strdup(comp_dir);
1847	if (!lr->comp_dir)
1848	ret = -ENOMEM;
1849	}
1850	}
1851
1852	pr_debug("path: %s\n", lr->path);
1853	return (ret < 0) ? ret : lf.found;
1854	}
1855
1856	/*
1857	* Find a src file from a DWARF tag path. Prepend optional source path prefix
1858	* and chop off leading directories that do not exist. Result is passed back as
1859	* a newly allocated path on success.
1860	* Return 0 if file was found and readable, -errno otherwise.
1861	*/
1862	int find_source_path(const char *raw_path, const char *sbuild_id,
1863	const char *comp_dir, char **new_path)
1864	{
1865	const char *prefix = symbol_conf.source_prefix;
1866
1867	if (sbuild_id && !prefix) {
1868	if (!get_source_from_debuginfod(raw_path, sbuild_id, new_path))
1869	return 0;
1870	}
1871
1872	if (!prefix) {
1873	if (raw_path[0] != '/' && comp_dir)
1874	/* If not an absolute path, try to use comp_dir */
1875	prefix = comp_dir;
1876	else {
1877	if (access(raw_path, R_OK) == 0) {
1878	*new_path = strdup(raw_path);
1879	return *new_path ? 0 : -ENOMEM;
1880	} else
1881	return -errno;
1882	}
1883	}
1884
1885	*new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1886	if (!*new_path)
1887	return -ENOMEM;
1888
1889	for (;;) {
1890	sprintf(buf: *new_path, fmt: "%s/%s", prefix, raw_path);
1891
1892	if (access(*new_path, R_OK) == 0)
1893	return 0;
1894
1895	if (!symbol_conf.source_prefix) {
1896	/* In case of searching comp_dir, don't retry */
1897	zfree(new_path);
1898	return -errno;
1899	}
1900
1901	switch (errno) {
1902	case ENAMETOOLONG:
1903	case ENOENT:
1904	case EROFS:
1905	case EFAULT:
1906	raw_path = strchr(++raw_path, '/');
1907	if (!raw_path) {
1908	zfree(new_path);
1909	return -ENOENT;
1910	}
1911	continue;
1912
1913	default:
1914	zfree(new_path);
1915	return -errno;
1916	}
1917	}
1918	}
1919