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
  42static 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 */
  57static 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	}
 119found:
 120	if (nops == 0)
 121		/* TODO: Support const_value */
 122		return -ENOENT;
 123
 124	if (op->atom == DW_OP_addr) {
 125static_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(tvar->value, ret + 2, "@%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
 191static 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, 16, "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, 16, "%c%d", prefix, ret);
 295
 296formatted:
 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
 310static 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
 429next:
 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
 438static 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 */
 447static 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(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 */
 478static 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(pf->pvar->var))
 486		return copy_to_probe_trace_arg(pf->tvar, pf->pvar);
 487
 488	if (pf->pvar->name)
 489		pf->tvar->name = strdup(pf->pvar->name);
 490	else {
 491		buf = synthesize_perf_probe_arg(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 */
 522static 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 */
 574static 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
 631struct 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
 640static 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 */
 673static 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 */
 683static 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
 704static 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
 737static 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(fname, 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 */
 764static 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 */
 770static 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(line, pat)) {
 793			intlist__add(list, 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
 809static 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(pf->lcache, lineno) ||
 817	    strtailcmp(fname, 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  */
 840static 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(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, pf->dbg->build_id, BUILD_ID_SIZE);
 853			build_id__sprintf(&bid, 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(pf->lcache, fpath,
 863					    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
 872static 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(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
 904static 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 */
 937struct dwarf_callback_param {
 938	void *data;
 939	int retval;
 940};
 941
 942/* Search function from function name */
 943static 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(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
1006static 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
1014struct pubname_callback_param {
1015	char *function;
1016	char *file;
1017	Dwarf_Die *cu_die;
1018	Dwarf_Die *sp_die;
1019	int found;
1020};
1021
1022static 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
1049static 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(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
1115found:
1116	intlist__delete(pf->lcache);
1117	pf->lcache = NULL;
1118
1119	return ret;
1120}
1121
1122/* Find probe points from debuginfo */
1123static 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
1159struct 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 */
1169static 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
1197static 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
1229static 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 */
1241static 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
1309end:
1310	if (ret) {
1311		clear_probe_trace_event(tev);
1312		tf->ntevs--;
1313	}
1314	free(args);
1315	return ret;
1316}
1317
1318static 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(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 */
1360int 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, &tf.pf);
1381	if (ret >= 0 && tf.pf.skip_empty_arg)
1382		ret = fill_empty_trace_arg(pev, tf.tevs, tf.ntevs);
1383
1384	if (ret < 0 || tf.ntevs == 0) {
1385		for (i = 0; i < tf.ntevs; i++)
1386			clear_probe_trace_event(&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 */
1395static 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, 64) < 0)
1415				goto error;
1416
1417			if (probe_conf.show_location_range) {
1418				if (!externs)
1419					ret2 = strbuf_add(&buf,
1420						ret ? "[INV]\t" : "[VAL]\t", 6);
1421				else
1422					ret2 = strbuf_add(&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(&buf, '\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(vl->vars,
1440					strbuf_detach(&buf, NULL));
1441			}
1442			strbuf_release(&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;
1450error:
1451	strbuf_release(&buf);
1452	pr_debug("Error in strbuf\n");
1453	return DIE_FIND_CB_END;
1454}
1455
1456static 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 */
1469static 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
1516out:
1517	if (strlist__empty(vl->vars)) {
1518		strlist__delete(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 */
1530int 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, &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(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 */
1563int 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
1639post:
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	}
1664end:
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 */
1671static 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(lr->line_list, lineno);
1681}
1682
1683static 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(fname, 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(fname, lineno, 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 */
1708static 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(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
1726static 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 */
1740static 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
1777static 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
1784int 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);
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
1841found:
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 */
1862int 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(*new_path, "%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}