1/*
   2 * probe-finder.c : C expression to kprobe event converter
   3 *
   4 * Written by Masami Hiramatsu <mhiramat@redhat.com>
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation; either version 2 of the License, or
   9 * (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 * GNU General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public License
  17 * along with this program; if not, write to the Free Software
  18 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  19 *
  20 */
  21
 
  22#include <sys/utsname.h>
  23#include <sys/types.h>
  24#include <sys/stat.h>
  25#include <fcntl.h>
  26#include <errno.h>
  27#include <stdio.h>
  28#include <unistd.h>
  29#include <stdlib.h>
  30#include <string.h>
  31#include <stdarg.h>
  32#include <dwarf-regs.h>
  33
  34#include <linux/bitops.h>
 
  35#include "event.h"
  36#include "dso.h"
  37#include "debug.h"
 
  38#include "intlist.h"
  39#include "util.h"
 
  40#include "symbol.h"
  41#include "probe-finder.h"
 
 
  42
  43/* Kprobe tracer basic type is up to u64 */
  44#define MAX_BASIC_TYPE_BITS	64
  45
  46/* Dwarf FL wrappers */
  47static char *debuginfo_path;	/* Currently dummy */
  48
  49static const Dwfl_Callbacks offline_callbacks = {
  50	.find_debuginfo = dwfl_standard_find_debuginfo,
  51	.debuginfo_path = &debuginfo_path,
  52
  53	.section_address = dwfl_offline_section_address,
  54
  55	/* We use this table for core files too.  */
  56	.find_elf = dwfl_build_id_find_elf,
  57};
  58
  59/* Get a Dwarf from offline image */
  60static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
  61					 const char *path)
  62{
  63	int fd;
  64
  65	fd = open(path, O_RDONLY);
  66	if (fd < 0)
  67		return fd;
  68
  69	dbg->dwfl = dwfl_begin(&offline_callbacks);
  70	if (!dbg->dwfl)
  71		goto error;
  72
  73	dwfl_report_begin(dbg->dwfl);
  74	dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
  75	if (!dbg->mod)
  76		goto error;
  77
  78	dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
  79	if (!dbg->dbg)
  80		goto error;
  81
  82	dwfl_report_end(dbg->dwfl, NULL, NULL);
  83
  84	return 0;
  85error:
  86	if (dbg->dwfl)
  87		dwfl_end(dbg->dwfl);
  88	else
  89		close(fd);
  90	memset(dbg, 0, sizeof(*dbg));
  91
  92	return -ENOENT;
  93}
  94
  95static struct debuginfo *__debuginfo__new(const char *path)
  96{
  97	struct debuginfo *dbg = zalloc(sizeof(*dbg));
  98	if (!dbg)
  99		return NULL;
 100
 101	if (debuginfo__init_offline_dwarf(dbg, path) < 0)
 102		zfree(&dbg);
 103	if (dbg)
 104		pr_debug("Open Debuginfo file: %s\n", path);
 105	return dbg;
 106}
 107
 108enum dso_binary_type distro_dwarf_types[] = {
 109	DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
 110	DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
 111	DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
 112	DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
 113	DSO_BINARY_TYPE__NOT_FOUND,
 114};
 115
 116struct debuginfo *debuginfo__new(const char *path)
 117{
 118	enum dso_binary_type *type;
 119	char buf[PATH_MAX], nil = '\0';
 120	struct dso *dso;
 121	struct debuginfo *dinfo = NULL;
 122
 123	/* Try to open distro debuginfo files */
 124	dso = dso__new(path);
 125	if (!dso)
 126		goto out;
 127
 128	for (type = distro_dwarf_types;
 129	     !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND;
 130	     type++) {
 131		if (dso__read_binary_type_filename(dso, *type, &nil,
 132						   buf, PATH_MAX) < 0)
 133			continue;
 134		dinfo = __debuginfo__new(buf);
 135	}
 136	dso__put(dso);
 137
 138out:
 139	/* if failed to open all distro debuginfo, open given binary */
 140	return dinfo ? : __debuginfo__new(path);
 141}
 142
 143void debuginfo__delete(struct debuginfo *dbg)
 144{
 145	if (dbg) {
 146		if (dbg->dwfl)
 147			dwfl_end(dbg->dwfl);
 148		free(dbg);
 149	}
 150}
 151
 152/*
 153 * Probe finder related functions
 154 */
 155
 156static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
 157{
 158	struct probe_trace_arg_ref *ref;
 159	ref = zalloc(sizeof(struct probe_trace_arg_ref));
 160	if (ref != NULL)
 161		ref->offset = offs;
 162	return ref;
 163}
 164
 165/*
 166 * Convert a location into trace_arg.
 167 * If tvar == NULL, this just checks variable can be converted.
 168 * If fentry == true and vr_die is a parameter, do huristic search
 169 * for the location fuzzed by function entry mcount.
 170 */
 171static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
 172				     Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
 
 173				     struct probe_trace_arg *tvar)
 174{
 175	Dwarf_Attribute attr;
 176	Dwarf_Addr tmp = 0;
 177	Dwarf_Op *op;
 178	size_t nops;
 179	unsigned int regn;
 180	Dwarf_Word offs = 0;
 181	bool ref = false;
 182	const char *regs;
 183	int ret, ret2 = 0;
 184
 185	if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
 186		goto static_var;
 187
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 188	/* TODO: handle more than 1 exprs */
 189	if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
 190		return -EINVAL;	/* Broken DIE ? */
 191	if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
 192		ret = dwarf_entrypc(sp_die, &tmp);
 193		if (ret)
 194			return -ENOENT;
 195
 196		if (probe_conf.show_location_range &&
 197			(dwarf_tag(vr_die) == DW_TAG_variable)) {
 198			ret2 = -ERANGE;
 199		} else if (addr != tmp ||
 200			dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
 201			return -ENOENT;
 202		}
 203
 204		ret = dwarf_highpc(sp_die, &tmp);
 205		if (ret)
 206			return -ENOENT;
 207		/*
 208		 * This is fuzzed by fentry mcount. We try to find the
 209		 * parameter location at the earliest address.
 210		 */
 211		for (addr += 1; addr <= tmp; addr++) {
 212			if (dwarf_getlocation_addr(&attr, addr, &op,
 213						   &nops, 1) > 0)
 214				goto found;
 215		}
 216		return -ENOENT;
 217	}
 218found:
 219	if (nops == 0)
 220		/* TODO: Support const_value */
 221		return -ENOENT;
 222
 223	if (op->atom == DW_OP_addr) {
 224static_var:
 225		if (!tvar)
 226			return ret2;
 227		/* Static variables on memory (not stack), make @varname */
 228		ret = strlen(dwarf_diename(vr_die));
 229		tvar->value = zalloc(ret + 2);
 230		if (tvar->value == NULL)
 231			return -ENOMEM;
 232		snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
 233		tvar->ref = alloc_trace_arg_ref((long)offs);
 234		if (tvar->ref == NULL)
 235			return -ENOMEM;
 236		return ret2;
 237	}
 238
 239	/* If this is based on frame buffer, set the offset */
 240	if (op->atom == DW_OP_fbreg) {
 241		if (fb_ops == NULL)
 242			return -ENOTSUP;
 243		ref = true;
 244		offs = op->number;
 245		op = &fb_ops[0];
 246	}
 247
 248	if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
 249		regn = op->atom - DW_OP_breg0;
 250		offs += op->number;
 251		ref = true;
 252	} else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
 253		regn = op->atom - DW_OP_reg0;
 254	} else if (op->atom == DW_OP_bregx) {
 255		regn = op->number;
 256		offs += op->number2;
 257		ref = true;
 258	} else if (op->atom == DW_OP_regx) {
 259		regn = op->number;
 260	} else {
 261		pr_debug("DW_OP %x is not supported.\n", op->atom);
 262		return -ENOTSUP;
 263	}
 264
 265	if (!tvar)
 266		return ret2;
 267
 268	regs = get_arch_regstr(regn);
 269	if (!regs) {
 270		/* This should be a bug in DWARF or this tool */
 271		pr_warning("Mapping for the register number %u "
 272			   "missing on this architecture.\n", regn);
 273		return -ENOTSUP;
 274	}
 275
 276	tvar->value = strdup(regs);
 277	if (tvar->value == NULL)
 278		return -ENOMEM;
 279
 280	if (ref) {
 281		tvar->ref = alloc_trace_arg_ref((long)offs);
 282		if (tvar->ref == NULL)
 283			return -ENOMEM;
 284	}
 285	return ret2;
 286}
 287
 288#define BYTES_TO_BITS(nb)	((nb) * BITS_PER_LONG / sizeof(long))
 289
 290static int convert_variable_type(Dwarf_Die *vr_die,
 291				 struct probe_trace_arg *tvar,
 292				 const char *cast)
 293{
 294	struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
 295	Dwarf_Die type;
 296	char buf[16];
 297	char sbuf[STRERR_BUFSIZE];
 298	int bsize, boffs, total;
 299	int ret;
 
 300
 301	/* TODO: check all types */
 302	if (cast && strcmp(cast, "string") != 0) {
 
 
 303		/* Non string type is OK */
 
 304		tvar->type = strdup(cast);
 305		return (tvar->type == NULL) ? -ENOMEM : 0;
 306	}
 307
 308	bsize = dwarf_bitsize(vr_die);
 309	if (bsize > 0) {
 310		/* This is a bitfield */
 311		boffs = dwarf_bitoffset(vr_die);
 312		total = dwarf_bytesize(vr_die);
 313		if (boffs < 0 || total < 0)
 314			return -ENOENT;
 315		ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
 316				BYTES_TO_BITS(total));
 317		goto formatted;
 318	}
 319
 320	if (die_get_real_type(vr_die, &type) == NULL) {
 321		pr_warning("Failed to get a type information of %s.\n",
 322			   dwarf_diename(vr_die));
 323		return -ENOENT;
 324	}
 325
 326	pr_debug("%s type is %s.\n",
 327		 dwarf_diename(vr_die), dwarf_diename(&type));
 328
 329	if (cast && strcmp(cast, "string") == 0) {	/* String type */
 
 330		ret = dwarf_tag(&type);
 331		if (ret != DW_TAG_pointer_type &&
 332		    ret != DW_TAG_array_type) {
 333			pr_warning("Failed to cast into string: "
 334				   "%s(%s) is not a pointer nor array.\n",
 335				   dwarf_diename(vr_die), dwarf_diename(&type));
 336			return -EINVAL;
 337		}
 338		if (die_get_real_type(&type, &type) == NULL) {
 339			pr_warning("Failed to get a type"
 340				   " information.\n");
 341			return -ENOENT;
 342		}
 343		if (ret == DW_TAG_pointer_type) {
 344			while (*ref_ptr)
 345				ref_ptr = &(*ref_ptr)->next;
 346			/* Add new reference with offset +0 */
 347			*ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
 348			if (*ref_ptr == NULL) {
 349				pr_warning("Out of memory error\n");
 350				return -ENOMEM;
 351			}
 
 352		}
 353		if (!die_compare_name(&type, "char") &&
 354		    !die_compare_name(&type, "unsigned char")) {
 355			pr_warning("Failed to cast into string: "
 356				   "%s is not (unsigned) char *.\n",
 357				   dwarf_diename(vr_die));
 358			return -EINVAL;
 359		}
 360		tvar->type = strdup(cast);
 361		return (tvar->type == NULL) ? -ENOMEM : 0;
 362	}
 363
 
 
 
 
 
 
 
 
 
 
 
 364	ret = dwarf_bytesize(&type);
 365	if (ret <= 0)
 366		/* No size ... try to use default type */
 367		return 0;
 368	ret = BYTES_TO_BITS(ret);
 369
 370	/* Check the bitwidth */
 371	if (ret > MAX_BASIC_TYPE_BITS) {
 372		pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
 373			dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
 374		ret = MAX_BASIC_TYPE_BITS;
 375	}
 376	ret = snprintf(buf, 16, "%c%d",
 377		       die_is_signed_type(&type) ? 's' : 'u', ret);
 378
 379formatted:
 380	if (ret < 0 || ret >= 16) {
 381		if (ret >= 16)
 382			ret = -E2BIG;
 383		pr_warning("Failed to convert variable type: %s\n",
 384			   strerror_r(-ret, sbuf, sizeof(sbuf)));
 385		return ret;
 386	}
 387	tvar->type = strdup(buf);
 388	if (tvar->type == NULL)
 389		return -ENOMEM;
 390	return 0;
 391}
 392
 393static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
 394				    struct perf_probe_arg_field *field,
 395				    struct probe_trace_arg_ref **ref_ptr,
 396				    Dwarf_Die *die_mem)
 397{
 398	struct probe_trace_arg_ref *ref = *ref_ptr;
 399	Dwarf_Die type;
 400	Dwarf_Word offs;
 401	int ret, tag;
 402
 403	pr_debug("converting %s in %s\n", field->name, varname);
 404	if (die_get_real_type(vr_die, &type) == NULL) {
 405		pr_warning("Failed to get the type of %s.\n", varname);
 406		return -ENOENT;
 407	}
 408	pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
 
 409	tag = dwarf_tag(&type);
 410
 411	if (field->name[0] == '[' &&
 412	    (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
 413		if (field->next)
 414			/* Save original type for next field */
 415			memcpy(die_mem, &type, sizeof(*die_mem));
 416		/* Get the type of this array */
 417		if (die_get_real_type(&type, &type) == NULL) {
 418			pr_warning("Failed to get the type of %s.\n", varname);
 419			return -ENOENT;
 420		}
 421		pr_debug2("Array real type: (%x)\n",
 422			 (unsigned)dwarf_dieoffset(&type));
 423		if (tag == DW_TAG_pointer_type) {
 424			ref = zalloc(sizeof(struct probe_trace_arg_ref));
 425			if (ref == NULL)
 426				return -ENOMEM;
 427			if (*ref_ptr)
 428				(*ref_ptr)->next = ref;
 429			else
 430				*ref_ptr = ref;
 431		}
 432		ref->offset += dwarf_bytesize(&type) * field->index;
 433		if (!field->next)
 434			/* Save vr_die for converting types */
 435			memcpy(die_mem, vr_die, sizeof(*die_mem));
 436		goto next;
 437	} else if (tag == DW_TAG_pointer_type) {
 438		/* Check the pointer and dereference */
 439		if (!field->ref) {
 440			pr_err("Semantic error: %s must be referred by '->'\n",
 441			       field->name);
 442			return -EINVAL;
 443		}
 444		/* Get the type pointed by this pointer */
 445		if (die_get_real_type(&type, &type) == NULL) {
 446			pr_warning("Failed to get the type of %s.\n", varname);
 447			return -ENOENT;
 448		}
 449		/* Verify it is a data structure  */
 450		tag = dwarf_tag(&type);
 451		if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 452			pr_warning("%s is not a data structure nor an union.\n",
 453				   varname);
 454			return -EINVAL;
 455		}
 456
 457		ref = zalloc(sizeof(struct probe_trace_arg_ref));
 458		if (ref == NULL)
 459			return -ENOMEM;
 460		if (*ref_ptr)
 461			(*ref_ptr)->next = ref;
 462		else
 463			*ref_ptr = ref;
 464	} else {
 465		/* Verify it is a data structure  */
 466		if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 467			pr_warning("%s is not a data structure nor an union.\n",
 468				   varname);
 469			return -EINVAL;
 470		}
 471		if (field->name[0] == '[') {
 472			pr_err("Semantic error: %s is not a pointer"
 473			       " nor array.\n", varname);
 474			return -EINVAL;
 475		}
 476		/* While prcessing unnamed field, we don't care about this */
 477		if (field->ref && dwarf_diename(vr_die)) {
 478			pr_err("Semantic error: %s must be referred by '.'\n",
 479			       field->name);
 480			return -EINVAL;
 481		}
 482		if (!ref) {
 483			pr_warning("Structure on a register is not "
 484				   "supported yet.\n");
 485			return -ENOTSUP;
 486		}
 487	}
 488
 489	if (die_find_member(&type, field->name, die_mem) == NULL) {
 490		pr_warning("%s(type:%s) has no member %s.\n", varname,
 491			   dwarf_diename(&type), field->name);
 492		return -EINVAL;
 493	}
 494
 495	/* Get the offset of the field */
 496	if (tag == DW_TAG_union_type) {
 497		offs = 0;
 498	} else {
 499		ret = die_get_data_member_location(die_mem, &offs);
 500		if (ret < 0) {
 501			pr_warning("Failed to get the offset of %s.\n",
 502				   field->name);
 503			return ret;
 504		}
 505	}
 506	ref->offset += (long)offs;
 
 507
 508	/* If this member is unnamed, we need to reuse this field */
 509	if (!dwarf_diename(die_mem))
 510		return convert_variable_fields(die_mem, varname, field,
 511						&ref, die_mem);
 512
 513next:
 514	/* Converting next field */
 515	if (field->next)
 516		return convert_variable_fields(die_mem, field->name,
 517					field->next, &ref, die_mem);
 518	else
 519		return 0;
 520}
 521
 
 
 
 
 
 
 
 
 522/* Show a variables in kprobe event format */
 523static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 524{
 525	Dwarf_Die die_mem;
 526	int ret;
 527
 528	pr_debug("Converting variable %s into trace event.\n",
 529		 dwarf_diename(vr_die));
 530
 531	ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
 532					&pf->sp_die, pf->tvar);
 
 
 
 533	if (ret == -ENOENT || ret == -EINVAL) {
 534		pr_err("Failed to find the location of the '%s' variable at this address.\n"
 535		       " Perhaps it has been optimized out.\n"
 536		       " Use -V with the --range option to show '%s' location range.\n",
 537		       pf->pvar->var, pf->pvar->var);
 538	} else if (ret == -ENOTSUP)
 539		pr_err("Sorry, we don't support this variable location yet.\n");
 540	else if (ret == 0 && pf->pvar->field) {
 541		ret = convert_variable_fields(vr_die, pf->pvar->var,
 542					      pf->pvar->field, &pf->tvar->ref,
 543					      &die_mem);
 544		vr_die = &die_mem;
 545	}
 546	if (ret == 0)
 547		ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
 
 548	/* *expr will be cached in libdw. Don't free it. */
 549	return ret;
 550}
 551
 552/* Find a variable in a scope DIE */
 553static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
 554{
 555	Dwarf_Die vr_die;
 556	char buf[32], *ptr;
 557	int ret = 0;
 558
 559	/* Copy raw parameters */
 560	if (!is_c_varname(pf->pvar->var))
 561		return copy_to_probe_trace_arg(pf->tvar, pf->pvar);
 562
 563	if (pf->pvar->name)
 564		pf->tvar->name = strdup(pf->pvar->name);
 565	else {
 566		ret = synthesize_perf_probe_arg(pf->pvar, buf, 32);
 567		if (ret < 0)
 568			return ret;
 569		ptr = strchr(buf, ':');	/* Change type separator to _ */
 570		if (ptr)
 571			*ptr = '_';
 572		pf->tvar->name = strdup(buf);
 573	}
 574	if (pf->tvar->name == NULL)
 575		return -ENOMEM;
 576
 577	pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
 578	/* Search child die for local variables and parameters. */
 579	if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
 580		/* Search again in global variables */
 581		if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
 582						0, &vr_die)) {
 
 
 583			pr_warning("Failed to find '%s' in this function.\n",
 584				   pf->pvar->var);
 585			ret = -ENOENT;
 586		}
 587	}
 588	if (ret >= 0)
 589		ret = convert_variable(&vr_die, pf);
 590
 591	return ret;
 592}
 593
 594/* Convert subprogram DIE to trace point */
 595static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
 596				  Dwarf_Addr paddr, bool retprobe,
 597				  const char *function,
 598				  struct probe_trace_point *tp)
 599{
 600	Dwarf_Addr eaddr, highaddr;
 601	GElf_Sym sym;
 602	const char *symbol;
 603
 604	/* Verify the address is correct */
 605	if (dwarf_entrypc(sp_die, &eaddr) != 0) {
 606		pr_warning("Failed to get entry address of %s\n",
 607			   dwarf_diename(sp_die));
 608		return -ENOENT;
 609	}
 610	if (dwarf_highpc(sp_die, &highaddr) != 0) {
 611		pr_warning("Failed to get end address of %s\n",
 612			   dwarf_diename(sp_die));
 613		return -ENOENT;
 614	}
 615	if (paddr > highaddr) {
 616		pr_warning("Offset specified is greater than size of %s\n",
 617			   dwarf_diename(sp_die));
 618		return -EINVAL;
 619	}
 620
 621	symbol = dwarf_diename(sp_die);
 622	if (!symbol) {
 623		/* Try to get the symbol name from symtab */
 
 
 624		symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
 625		if (!symbol) {
 626			pr_warning("Failed to find symbol at 0x%lx\n",
 627				   (unsigned long)paddr);
 628			return -ENOENT;
 629		}
 630		eaddr = sym.st_value;
 631	}
 
 
 
 
 
 
 632	tp->offset = (unsigned long)(paddr - eaddr);
 633	tp->address = (unsigned long)paddr;
 634	tp->symbol = strdup(symbol);
 635	if (!tp->symbol)
 636		return -ENOMEM;
 637
 638	/* Return probe must be on the head of a subprogram */
 639	if (retprobe) {
 640		if (eaddr != paddr) {
 641			pr_warning("Failed to find \"%s%%return\",\n"
 642				   " because %s is an inlined function and"
 643				   " has no return point.\n", function,
 644				   function);
 645			return -EINVAL;
 646		}
 647		tp->retprobe = true;
 648	}
 649
 650	return 0;
 651}
 652
 653/* Call probe_finder callback with scope DIE */
 654static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
 655{
 656	Dwarf_Attribute fb_attr;
 657	Dwarf_Frame *frame = NULL;
 658	size_t nops;
 659	int ret;
 660
 661	if (!sc_die) {
 662		pr_err("Caller must pass a scope DIE. Program error.\n");
 663		return -EINVAL;
 664	}
 665
 666	/* If not a real subprogram, find a real one */
 667	if (!die_is_func_def(sc_die)) {
 668		if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 669			if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 670				pr_warning("Ignoring tail call from %s\n",
 671						dwarf_diename(&pf->sp_die));
 672				return 0;
 673			} else {
 674				pr_warning("Failed to find probe point in any "
 675					   "functions.\n");
 676				return -ENOENT;
 677			}
 678		}
 679	} else
 680		memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
 681
 682	/* Get the frame base attribute/ops from subprogram */
 683	dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
 684	ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
 685	if (ret <= 0 || nops == 0) {
 686		pf->fb_ops = NULL;
 687#if _ELFUTILS_PREREQ(0, 142)
 688	} else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
 689		   (pf->cfi_eh != NULL || pf->cfi_dbg != NULL)) {
 690		if ((dwarf_cfi_addrframe(pf->cfi_eh, pf->addr, &frame) != 0 &&
 691		     (dwarf_cfi_addrframe(pf->cfi_dbg, pf->addr, &frame) != 0)) ||
 692		    dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
 693			pr_warning("Failed to get call frame on 0x%jx\n",
 694				   (uintmax_t)pf->addr);
 695			free(frame);
 696			return -ENOENT;
 697		}
 698#endif
 699	}
 700
 701	/* Call finder's callback handler */
 702	ret = pf->callback(sc_die, pf);
 703
 704	/* Since *pf->fb_ops can be a part of frame. we should free it here. */
 705	free(frame);
 706	pf->fb_ops = NULL;
 707
 708	return ret;
 709}
 710
 711struct find_scope_param {
 712	const char *function;
 713	const char *file;
 714	int line;
 715	int diff;
 716	Dwarf_Die *die_mem;
 717	bool found;
 718};
 719
 720static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
 721{
 722	struct find_scope_param *fsp = data;
 723	const char *file;
 724	int lno;
 725
 726	/* Skip if declared file name does not match */
 727	if (fsp->file) {
 728		file = dwarf_decl_file(fn_die);
 729		if (!file || strcmp(fsp->file, file) != 0)
 730			return 0;
 731	}
 732	/* If the function name is given, that's what user expects */
 733	if (fsp->function) {
 734		if (die_match_name(fn_die, fsp->function)) {
 735			memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 736			fsp->found = true;
 737			return 1;
 738		}
 739	} else {
 740		/* With the line number, find the nearest declared DIE */
 741		dwarf_decl_line(fn_die, &lno);
 742		if (lno < fsp->line && fsp->diff > fsp->line - lno) {
 743			/* Keep a candidate and continue */
 744			fsp->diff = fsp->line - lno;
 745			memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 746			fsp->found = true;
 747		}
 748	}
 749	return 0;
 750}
 751
 
 
 
 
 
 
 
 
 
 
 752/* Find an appropriate scope fits to given conditions */
 753static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
 754{
 755	struct find_scope_param fsp = {
 756		.function = pf->pev->point.function,
 757		.file = pf->fname,
 758		.line = pf->lno,
 759		.diff = INT_MAX,
 760		.die_mem = die_mem,
 761		.found = false,
 762	};
 
 763
 764	cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
 
 
 
 
 765
 766	return fsp.found ? die_mem : NULL;
 767}
 768
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 769static int probe_point_line_walker(const char *fname, int lineno,
 770				   Dwarf_Addr addr, void *data)
 771{
 772	struct probe_finder *pf = data;
 773	Dwarf_Die *sc_die, die_mem;
 774	int ret;
 775
 776	if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
 777		return 0;
 778
 
 
 
 779	pf->addr = addr;
 780	sc_die = find_best_scope(pf, &die_mem);
 781	if (!sc_die) {
 782		pr_warning("Failed to find scope of probe point.\n");
 783		return -ENOENT;
 784	}
 785
 786	ret = call_probe_finder(sc_die, pf);
 787
 788	/* Continue if no error, because the line will be in inline function */
 789	return ret < 0 ? ret : 0;
 790}
 791
 792/* Find probe point from its line number */
 793static int find_probe_point_by_line(struct probe_finder *pf)
 794{
 795	return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
 796}
 797
 798/* Find lines which match lazy pattern */
 799static int find_lazy_match_lines(struct intlist *list,
 800				 const char *fname, const char *pat)
 801{
 802	FILE *fp;
 803	char *line = NULL;
 804	size_t line_len;
 805	ssize_t len;
 806	int count = 0, linenum = 1;
 807	char sbuf[STRERR_BUFSIZE];
 808
 809	fp = fopen(fname, "r");
 810	if (!fp) {
 811		pr_warning("Failed to open %s: %s\n", fname,
 812			   strerror_r(errno, sbuf, sizeof(sbuf)));
 813		return -errno;
 814	}
 815
 816	while ((len = getline(&line, &line_len, fp)) > 0) {
 817
 818		if (line[len - 1] == '\n')
 819			line[len - 1] = '\0';
 820
 821		if (strlazymatch(line, pat)) {
 822			intlist__add(list, linenum);
 823			count++;
 824		}
 825		linenum++;
 826	}
 827
 828	if (ferror(fp))
 829		count = -errno;
 830	free(line);
 831	fclose(fp);
 832
 833	if (count == 0)
 834		pr_debug("No matched lines found in %s.\n", fname);
 835	return count;
 836}
 837
 838static int probe_point_lazy_walker(const char *fname, int lineno,
 839				   Dwarf_Addr addr, void *data)
 840{
 841	struct probe_finder *pf = data;
 842	Dwarf_Die *sc_die, die_mem;
 843	int ret;
 844
 845	if (!intlist__has_entry(pf->lcache, lineno) ||
 846	    strtailcmp(fname, pf->fname) != 0)
 847		return 0;
 848
 849	pr_debug("Probe line found: line:%d addr:0x%llx\n",
 850		 lineno, (unsigned long long)addr);
 851	pf->addr = addr;
 852	pf->lno = lineno;
 853	sc_die = find_best_scope(pf, &die_mem);
 854	if (!sc_die) {
 855		pr_warning("Failed to find scope of probe point.\n");
 856		return -ENOENT;
 857	}
 858
 859	ret = call_probe_finder(sc_die, pf);
 860
 861	/*
 862	 * Continue if no error, because the lazy pattern will match
 863	 * to other lines
 864	 */
 865	return ret < 0 ? ret : 0;
 866}
 867
 868/* Find probe points from lazy pattern  */
 869static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
 870{
 
 
 871	int ret = 0;
 872	char *fpath;
 873
 874	if (intlist__empty(pf->lcache)) {
 875		const char *comp_dir;
 876
 877		comp_dir = cu_get_comp_dir(&pf->cu_die);
 878		ret = get_real_path(pf->fname, comp_dir, &fpath);
 
 
 
 
 879		if (ret < 0) {
 880			pr_warning("Failed to find source file path.\n");
 881			return ret;
 882		}
 883
 884		/* Matching lazy line pattern */
 885		ret = find_lazy_match_lines(pf->lcache, fpath,
 886					    pf->pev->point.lazy_line);
 887		free(fpath);
 888		if (ret <= 0)
 889			return ret;
 890	}
 891
 892	return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
 893}
 894
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 895static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
 896{
 897	struct probe_finder *pf = data;
 898	struct perf_probe_point *pp = &pf->pev->point;
 899	Dwarf_Addr addr;
 900	int ret;
 901
 902	if (pp->lazy_line)
 903		ret = find_probe_point_lazy(in_die, pf);
 904	else {
 905		/* Get probe address */
 906		if (dwarf_entrypc(in_die, &addr) != 0) {
 907			pr_warning("Failed to get entry address of %s.\n",
 908				   dwarf_diename(in_die));
 909			return -ENOENT;
 910		}
 
 
 
 
 
 911		pf->addr = addr;
 912		pf->addr += pp->offset;
 913		pr_debug("found inline addr: 0x%jx\n",
 914			 (uintmax_t)pf->addr);
 915
 916		ret = call_probe_finder(in_die, pf);
 917	}
 918
 919	return ret;
 920}
 921
 922/* Callback parameter with return value for libdw */
 923struct dwarf_callback_param {
 924	void *data;
 925	int retval;
 926};
 927
 928/* Search function from function name */
 929static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
 930{
 931	struct dwarf_callback_param *param = data;
 932	struct probe_finder *pf = param->data;
 933	struct perf_probe_point *pp = &pf->pev->point;
 
 934
 935	/* Check tag and diename */
 936	if (!die_is_func_def(sp_die) ||
 937	    !die_match_name(sp_die, pp->function))
 938		return DWARF_CB_OK;
 939
 940	/* Check declared file */
 941	if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
 
 
 
 
 
 942		return DWARF_CB_OK;
 943
 944	pr_debug("Matched function: %s\n", dwarf_diename(sp_die));
 945	pf->fname = dwarf_decl_file(sp_die);
 
 946	if (pp->line) { /* Function relative line */
 947		dwarf_decl_line(sp_die, &pf->lno);
 948		pf->lno += pp->line;
 949		param->retval = find_probe_point_by_line(pf);
 950	} else if (die_is_func_instance(sp_die)) {
 951		/* Instances always have the entry address */
 952		dwarf_entrypc(sp_die, &pf->addr);
 
 
 
 
 
 953		/* Real function */
 954		if (pp->lazy_line)
 955			param->retval = find_probe_point_lazy(sp_die, pf);
 956		else {
 
 957			pf->addr += pp->offset;
 958			/* TODO: Check the address in this function */
 959			param->retval = call_probe_finder(sp_die, pf);
 960		}
 961	} else if (!probe_conf.no_inlines) {
 962		/* Inlined function: search instances */
 963		param->retval = die_walk_instances(sp_die,
 964					probe_point_inline_cb, (void *)pf);
 965		/* This could be a non-existed inline definition */
 966		if (param->retval == -ENOENT && strisglob(pp->function))
 967			param->retval = 0;
 968	}
 969
 970	/* We need to find other candidates */
 971	if (strisglob(pp->function) && param->retval >= 0) {
 972		param->retval = 0;	/* We have to clear the result */
 973		return DWARF_CB_OK;
 974	}
 975
 976	return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
 977}
 978
 979static int find_probe_point_by_func(struct probe_finder *pf)
 980{
 981	struct dwarf_callback_param _param = {.data = (void *)pf,
 982					      .retval = 0};
 983	dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
 984	return _param.retval;
 985}
 986
 987struct pubname_callback_param {
 988	char *function;
 989	char *file;
 990	Dwarf_Die *cu_die;
 991	Dwarf_Die *sp_die;
 992	int found;
 993};
 994
 995static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
 996{
 997	struct pubname_callback_param *param = data;
 
 998
 999	if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1000		if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1001			return DWARF_CB_OK;
1002
1003		if (die_match_name(param->sp_die, param->function)) {
1004			if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1005				return DWARF_CB_OK;
1006
1007			if (param->file &&
1008			    strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1009				return DWARF_CB_OK;
 
 
1010
1011			param->found = 1;
1012			return DWARF_CB_ABORT;
1013		}
1014	}
1015
1016	return DWARF_CB_OK;
1017}
1018
1019static int debuginfo__find_probe_location(struct debuginfo *dbg,
1020				  struct probe_finder *pf)
1021{
1022	struct perf_probe_point *pp = &pf->pev->point;
1023	Dwarf_Off off, noff;
1024	size_t cuhl;
1025	Dwarf_Die *diep;
1026	int ret = 0;
1027
1028	off = 0;
1029	pf->lcache = intlist__new(NULL);
1030	if (!pf->lcache)
1031		return -ENOMEM;
1032
1033	/* Fastpath: lookup by function name from .debug_pubnames section */
1034	if (pp->function && !strisglob(pp->function)) {
1035		struct pubname_callback_param pubname_param = {
1036			.function = pp->function,
1037			.file	  = pp->file,
1038			.cu_die	  = &pf->cu_die,
1039			.sp_die	  = &pf->sp_die,
1040			.found	  = 0,
1041		};
1042		struct dwarf_callback_param probe_param = {
1043			.data = pf,
1044		};
1045
1046		dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1047				  &pubname_param, 0);
1048		if (pubname_param.found) {
1049			ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1050			if (ret)
1051				goto found;
1052		}
1053	}
1054
1055	/* Loop on CUs (Compilation Unit) */
1056	while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1057		/* Get the DIE(Debugging Information Entry) of this CU */
1058		diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1059		if (!diep)
 
1060			continue;
 
1061
1062		/* Check if target file is included. */
1063		if (pp->file)
1064			pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1065		else
1066			pf->fname = NULL;
1067
1068		if (!pp->file || pf->fname) {
1069			if (pp->function)
1070				ret = find_probe_point_by_func(pf);
1071			else if (pp->lazy_line)
1072				ret = find_probe_point_lazy(&pf->cu_die, pf);
1073			else {
1074				pf->lno = pp->line;
1075				ret = find_probe_point_by_line(pf);
1076			}
1077			if (ret < 0)
1078				break;
1079		}
1080		off = noff;
1081	}
1082
1083found:
1084	intlist__delete(pf->lcache);
1085	pf->lcache = NULL;
1086
1087	return ret;
1088}
1089
1090/* Find probe points from debuginfo */
1091static int debuginfo__find_probes(struct debuginfo *dbg,
1092				  struct probe_finder *pf)
1093{
1094	int ret = 0;
1095
1096#if _ELFUTILS_PREREQ(0, 142)
1097	Elf *elf;
1098	GElf_Ehdr ehdr;
1099	GElf_Shdr shdr;
1100
1101	if (pf->cfi_eh || pf->cfi_dbg)
1102		return debuginfo__find_probe_location(dbg, pf);
1103
1104	/* Get the call frame information from this dwarf */
1105	elf = dwarf_getelf(dbg->dbg);
1106	if (elf == NULL)
1107		return -EINVAL;
1108
1109	if (gelf_getehdr(elf, &ehdr) == NULL)
1110		return -EINVAL;
1111
1112	if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1113	    shdr.sh_type == SHT_PROGBITS)
1114		pf->cfi_eh = dwarf_getcfi_elf(elf);
1115
1116	pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
1117#endif
 
 
 
 
 
 
 
 
 
1118
1119	ret = debuginfo__find_probe_location(dbg, pf);
1120	return ret;
1121}
1122
1123struct local_vars_finder {
1124	struct probe_finder *pf;
1125	struct perf_probe_arg *args;
1126	bool vars;
1127	int max_args;
1128	int nargs;
1129	int ret;
1130};
1131
1132/* Collect available variables in this scope */
1133static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1134{
1135	struct local_vars_finder *vf = data;
1136	struct probe_finder *pf = vf->pf;
1137	int tag;
1138
1139	tag = dwarf_tag(die_mem);
1140	if (tag == DW_TAG_formal_parameter ||
1141	    (tag == DW_TAG_variable && vf->vars)) {
1142		if (convert_variable_location(die_mem, vf->pf->addr,
1143					      vf->pf->fb_ops, &pf->sp_die,
1144					      NULL) == 0) {
1145			vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1146			if (vf->args[vf->nargs].var == NULL) {
1147				vf->ret = -ENOMEM;
1148				return DIE_FIND_CB_END;
1149			}
1150			pr_debug(" %s", vf->args[vf->nargs].var);
1151			vf->nargs++;
1152		}
1153	}
1154
1155	if (dwarf_haspc(die_mem, vf->pf->addr))
1156		return DIE_FIND_CB_CONTINUE;
1157	else
1158		return DIE_FIND_CB_SIBLING;
1159}
1160
1161static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1162			     struct perf_probe_arg *args)
1163{
1164	Dwarf_Die die_mem;
1165	int i;
1166	int n = 0;
1167	struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1168				.max_args = MAX_PROBE_ARGS, .ret = 0};
1169
1170	for (i = 0; i < pf->pev->nargs; i++) {
1171		/* var never be NULL */
1172		if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1173			vf.vars = true;
1174		else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1175			/* Copy normal argument */
1176			args[n] = pf->pev->args[i];
1177			n++;
1178			continue;
1179		}
1180		pr_debug("Expanding %s into:", pf->pev->args[i].var);
1181		vf.nargs = n;
1182		/* Special local variables */
1183		die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1184			       &die_mem);
1185		pr_debug(" (%d)\n", vf.nargs - n);
1186		if (vf.ret < 0)
1187			return vf.ret;
1188		n = vf.nargs;
1189	}
1190	return n;
1191}
1192
 
 
 
 
 
 
 
 
 
 
 
1193/* Add a found probe point into trace event list */
1194static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1195{
1196	struct trace_event_finder *tf =
1197			container_of(pf, struct trace_event_finder, pf);
1198	struct perf_probe_point *pp = &pf->pev->point;
1199	struct probe_trace_event *tev;
1200	struct perf_probe_arg *args = NULL;
1201	int ret, i;
1202
 
 
 
 
 
 
 
 
1203	/* Check number of tevs */
1204	if (tf->ntevs == tf->max_tevs) {
1205		pr_warning("Too many( > %d) probe point found.\n",
1206			   tf->max_tevs);
1207		return -ERANGE;
1208	}
1209	tev = &tf->tevs[tf->ntevs++];
1210
1211	/* Trace point should be converted from subprogram DIE */
1212	ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1213				     pp->retprobe, pp->function, &tev->point);
1214	if (ret < 0)
1215		goto end;
1216
1217	tev->point.realname = strdup(dwarf_diename(sc_die));
1218	if (!tev->point.realname) {
1219		ret = -ENOMEM;
1220		goto end;
1221	}
1222
1223	pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1224		 tev->point.offset);
1225
1226	/* Expand special probe argument if exist */
1227	args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1228	if (args == NULL) {
1229		ret = -ENOMEM;
1230		goto end;
1231	}
1232
1233	ret = expand_probe_args(sc_die, pf, args);
1234	if (ret < 0)
1235		goto end;
1236
1237	tev->nargs = ret;
1238	tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1239	if (tev->args == NULL) {
1240		ret = -ENOMEM;
1241		goto end;
1242	}
1243
1244	/* Find each argument */
1245	for (i = 0; i < tev->nargs; i++) {
1246		pf->pvar = &args[i];
1247		pf->tvar = &tev->args[i];
1248		/* Variable should be found from scope DIE */
1249		ret = find_variable(sc_die, pf);
1250		if (ret != 0)
1251			break;
1252	}
1253
1254end:
1255	if (ret) {
1256		clear_probe_trace_event(tev);
1257		tf->ntevs--;
1258	}
1259	free(args);
1260	return ret;
1261}
1262
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1263/* Find probe_trace_events specified by perf_probe_event from debuginfo */
1264int debuginfo__find_trace_events(struct debuginfo *dbg,
1265				 struct perf_probe_event *pev,
1266				 struct probe_trace_event **tevs)
1267{
1268	struct trace_event_finder tf = {
1269			.pf = {.pev = pev, .callback = add_probe_trace_event},
1270			.max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1271	int ret, i;
1272
1273	/* Allocate result tevs array */
1274	*tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1275	if (*tevs == NULL)
1276		return -ENOMEM;
1277
1278	tf.tevs = *tevs;
1279	tf.ntevs = 0;
1280
 
 
 
1281	ret = debuginfo__find_probes(dbg, &tf.pf);
1282	if (ret < 0) {
 
 
 
1283		for (i = 0; i < tf.ntevs; i++)
1284			clear_probe_trace_event(&tf.tevs[i]);
1285		zfree(tevs);
1286		return ret;
1287	}
1288
1289	return (ret < 0) ? ret : tf.ntevs;
1290}
1291
1292/* Collect available variables in this scope */
1293static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1294{
1295	struct available_var_finder *af = data;
1296	struct variable_list *vl;
 
1297	int tag, ret;
1298
1299	vl = &af->vls[af->nvls - 1];
1300
1301	tag = dwarf_tag(die_mem);
1302	if (tag == DW_TAG_formal_parameter ||
1303	    tag == DW_TAG_variable) {
1304		ret = convert_variable_location(die_mem, af->pf.addr,
1305						af->pf.fb_ops, &af->pf.sp_die,
1306						NULL);
1307		if (ret == 0 || ret == -ERANGE) {
1308			int ret2;
1309			bool externs = !af->child;
1310			struct strbuf buf;
1311
1312			strbuf_init(&buf, 64);
 
1313
1314			if (probe_conf.show_location_range) {
1315				if (!externs) {
1316					if (ret)
1317						strbuf_add(&buf, "[INV]\t", 6);
1318					else
1319						strbuf_add(&buf, "[VAL]\t", 6);
1320				} else
1321					strbuf_add(&buf, "[EXT]\t", 6);
1322			}
1323
1324			ret2 = die_get_varname(die_mem, &buf);
1325
1326			if (!ret2 && probe_conf.show_location_range &&
1327				!externs) {
1328				strbuf_addch(&buf, '\t');
 
1329				ret2 = die_get_var_range(&af->pf.sp_die,
1330							die_mem, &buf);
1331			}
1332
1333			pr_debug("Add new var: %s\n", buf.buf);
1334			if (ret2 == 0) {
1335				strlist__add(vl->vars,
1336					strbuf_detach(&buf, NULL));
1337			}
1338			strbuf_release(&buf);
1339		}
1340	}
1341
1342	if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1343		return DIE_FIND_CB_CONTINUE;
1344	else
1345		return DIE_FIND_CB_SIBLING;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1346}
1347
1348/* Add a found vars into available variables list */
1349static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1350{
1351	struct available_var_finder *af =
1352			container_of(pf, struct available_var_finder, pf);
1353	struct perf_probe_point *pp = &pf->pev->point;
1354	struct variable_list *vl;
1355	Dwarf_Die die_mem;
1356	int ret;
1357
 
 
 
 
 
 
 
 
1358	/* Check number of tevs */
1359	if (af->nvls == af->max_vls) {
1360		pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1361		return -ERANGE;
1362	}
1363	vl = &af->vls[af->nvls++];
1364
1365	/* Trace point should be converted from subprogram DIE */
1366	ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1367				     pp->retprobe, pp->function, &vl->point);
1368	if (ret < 0)
1369		return ret;
1370
1371	pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1372		 vl->point.offset);
1373
1374	/* Find local variables */
1375	vl->vars = strlist__new(NULL, NULL);
1376	if (vl->vars == NULL)
1377		return -ENOMEM;
1378	af->child = true;
1379	die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1380
1381	/* Find external variables */
1382	if (!probe_conf.show_ext_vars)
1383		goto out;
1384	/* Don't need to search child DIE for external vars. */
1385	af->child = false;
1386	die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1387
1388out:
1389	if (strlist__empty(vl->vars)) {
1390		strlist__delete(vl->vars);
1391		vl->vars = NULL;
1392	}
1393
1394	return ret;
1395}
1396
1397/*
1398 * Find available variables at given probe point
1399 * Return the number of found probe points. Return 0 if there is no
1400 * matched probe point. Return <0 if an error occurs.
1401 */
1402int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1403				      struct perf_probe_event *pev,
1404				      struct variable_list **vls)
1405{
1406	struct available_var_finder af = {
1407			.pf = {.pev = pev, .callback = add_available_vars},
1408			.mod = dbg->mod,
1409			.max_vls = probe_conf.max_probes};
1410	int ret;
1411
1412	/* Allocate result vls array */
1413	*vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1414	if (*vls == NULL)
1415		return -ENOMEM;
1416
1417	af.vls = *vls;
1418	af.nvls = 0;
1419
1420	ret = debuginfo__find_probes(dbg, &af.pf);
1421	if (ret < 0) {
1422		/* Free vlist for error */
1423		while (af.nvls--) {
1424			zfree(&af.vls[af.nvls].point.symbol);
1425			strlist__delete(af.vls[af.nvls].vars);
1426		}
1427		zfree(vls);
1428		return ret;
1429	}
1430
1431	return (ret < 0) ? ret : af.nvls;
1432}
1433
1434/* For the kernel module, we need a special code to get a DIE */
1435static int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs)
1436{
1437	int n, i;
1438	Elf32_Word shndx;
1439	Elf_Scn *scn;
1440	Elf *elf;
1441	GElf_Shdr mem, *shdr;
1442	const char *p;
1443
1444	elf = dwfl_module_getelf(dbg->mod, &dbg->bias);
1445	if (!elf)
1446		return -EINVAL;
1447
1448	/* Get the number of relocations */
1449	n = dwfl_module_relocations(dbg->mod);
1450	if (n < 0)
1451		return -ENOENT;
1452	/* Search the relocation related .text section */
1453	for (i = 0; i < n; i++) {
1454		p = dwfl_module_relocation_info(dbg->mod, i, &shndx);
1455		if (strcmp(p, ".text") == 0) {
1456			/* OK, get the section header */
1457			scn = elf_getscn(elf, shndx);
1458			if (!scn)
1459				return -ENOENT;
1460			shdr = gelf_getshdr(scn, &mem);
1461			if (!shdr)
1462				return -ENOENT;
1463			*offs = shdr->sh_addr;
1464		}
1465	}
1466	return 0;
1467}
1468
1469/* Reverse search */
1470int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1471				struct perf_probe_point *ppt)
1472{
1473	Dwarf_Die cudie, spdie, indie;
1474	Dwarf_Addr _addr = 0, baseaddr = 0;
1475	const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1476	int baseline = 0, lineno = 0, ret = 0;
1477	bool reloc = false;
1478
1479retry:
 
 
1480	/* Find cu die */
1481	if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1482		if (!reloc && debuginfo__get_text_offset(dbg, &baseaddr) == 0) {
1483			addr += baseaddr;
1484			reloc = true;
1485			goto retry;
1486		}
1487		pr_warning("Failed to find debug information for address %lx\n",
1488			   addr);
1489		ret = -EINVAL;
1490		goto end;
1491	}
1492
1493	/* Find a corresponding line (filename and lineno) */
1494	cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1495	/* Don't care whether it failed or not */
1496
1497	/* Find a corresponding function (name, baseline and baseaddr) */
1498	if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1499		/* Get function entry information */
1500		func = basefunc = dwarf_diename(&spdie);
1501		if (!func ||
1502		    dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1503		    dwarf_decl_line(&spdie, &baseline) != 0) {
1504			lineno = 0;
1505			goto post;
1506		}
1507
1508		fname = dwarf_decl_file(&spdie);
1509		if (addr == (unsigned long)baseaddr) {
1510			/* Function entry - Relative line number is 0 */
1511			lineno = baseline;
1512			goto post;
1513		}
1514
1515		/* Track down the inline functions step by step */
1516		while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1517						&indie)) {
1518			/* There is an inline function */
1519			if (dwarf_entrypc(&indie, &_addr) == 0 &&
1520			    _addr == addr) {
1521				/*
1522				 * addr is at an inline function entry.
1523				 * In this case, lineno should be the call-site
1524				 * line number. (overwrite lineinfo)
1525				 */
1526				lineno = die_get_call_lineno(&indie);
1527				fname = die_get_call_file(&indie);
1528				break;
1529			} else {
1530				/*
1531				 * addr is in an inline function body.
1532				 * Since lineno points one of the lines
1533				 * of the inline function, baseline should
1534				 * be the entry line of the inline function.
1535				 */
1536				tmp = dwarf_diename(&indie);
1537				if (!tmp ||
1538				    dwarf_decl_line(&indie, &baseline) != 0)
1539					break;
1540				func = tmp;
1541				spdie = indie;
1542			}
1543		}
1544		/* Verify the lineno and baseline are in a same file */
1545		tmp = dwarf_decl_file(&spdie);
1546		if (!tmp || strcmp(tmp, fname) != 0)
1547			lineno = 0;
1548	}
1549
1550post:
1551	/* Make a relative line number or an offset */
1552	if (lineno)
1553		ppt->line = lineno - baseline;
1554	else if (basefunc) {
1555		ppt->offset = addr - (unsigned long)baseaddr;
1556		func = basefunc;
1557	}
1558
1559	/* Duplicate strings */
1560	if (func) {
1561		ppt->function = strdup(func);
1562		if (ppt->function == NULL) {
1563			ret = -ENOMEM;
1564			goto end;
1565		}
1566	}
1567	if (fname) {
1568		ppt->file = strdup(fname);
1569		if (ppt->file == NULL) {
1570			zfree(&ppt->function);
1571			ret = -ENOMEM;
1572			goto end;
1573		}
1574	}
1575end:
1576	if (ret == 0 && (fname || func))
1577		ret = 1;	/* Found a point */
1578	return ret;
1579}
1580
1581/* Add a line and store the src path */
1582static int line_range_add_line(const char *src, unsigned int lineno,
1583			       struct line_range *lr)
1584{
1585	/* Copy source path */
1586	if (!lr->path) {
1587		lr->path = strdup(src);
1588		if (lr->path == NULL)
1589			return -ENOMEM;
1590	}
1591	return intlist__add(lr->line_list, lineno);
1592}
1593
1594static int line_range_walk_cb(const char *fname, int lineno,
1595			      Dwarf_Addr addr __maybe_unused,
1596			      void *data)
1597{
1598	struct line_finder *lf = data;
 
 
1599	int err;
1600
1601	if ((strtailcmp(fname, lf->fname) != 0) ||
1602	    (lf->lno_s > lineno || lf->lno_e < lineno))
1603		return 0;
1604
 
 
 
 
 
1605	err = line_range_add_line(fname, lineno, lf->lr);
1606	if (err < 0 && err != -EEXIST)
1607		return err;
1608
1609	return 0;
1610}
1611
1612/* Find line range from its line number */
1613static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1614{
1615	int ret;
1616
1617	ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1618
1619	/* Update status */
1620	if (ret >= 0)
1621		if (!intlist__empty(lf->lr->line_list))
1622			ret = lf->found = 1;
1623		else
1624			ret = 0;	/* Lines are not found */
1625	else {
1626		zfree(&lf->lr->path);
1627	}
1628	return ret;
1629}
1630
1631static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1632{
1633	int ret = find_line_range_by_line(in_die, data);
1634
1635	/*
1636	 * We have to check all instances of inlined function, because
1637	 * some execution paths can be optimized out depends on the
1638	 * function argument of instances. However, if an error occurs,
1639	 * it should be handled by the caller.
1640	 */
1641	return ret < 0 ? ret : 0;
1642}
1643
1644/* Search function definition from function name */
1645static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1646{
1647	struct dwarf_callback_param *param = data;
1648	struct line_finder *lf = param->data;
1649	struct line_range *lr = lf->lr;
 
1650
1651	/* Check declared file */
1652	if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1653		return DWARF_CB_OK;
 
 
 
1654
1655	if (die_is_func_def(sp_die) &&
1656	    die_match_name(sp_die, lr->function)) {
1657		lf->fname = dwarf_decl_file(sp_die);
1658		dwarf_decl_line(sp_die, &lr->offset);
1659		pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1660		lf->lno_s = lr->offset + lr->start;
1661		if (lf->lno_s < 0)	/* Overflow */
1662			lf->lno_s = INT_MAX;
1663		lf->lno_e = lr->offset + lr->end;
1664		if (lf->lno_e < 0)	/* Overflow */
1665			lf->lno_e = INT_MAX;
1666		pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1667		lr->start = lf->lno_s;
1668		lr->end = lf->lno_e;
1669		if (!die_is_func_instance(sp_die))
1670			param->retval = die_walk_instances(sp_die,
1671						line_range_inline_cb, lf);
1672		else
1673			param->retval = find_line_range_by_line(sp_die, lf);
1674		return DWARF_CB_ABORT;
1675	}
1676	return DWARF_CB_OK;
1677}
1678
1679static int find_line_range_by_func(struct line_finder *lf)
1680{
1681	struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1682	dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1683	return param.retval;
1684}
1685
1686int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1687{
1688	struct line_finder lf = {.lr = lr, .found = 0};
1689	int ret = 0;
1690	Dwarf_Off off = 0, noff;
1691	size_t cuhl;
1692	Dwarf_Die *diep;
1693	const char *comp_dir;
1694
1695	/* Fastpath: lookup by function name from .debug_pubnames section */
1696	if (lr->function) {
1697		struct pubname_callback_param pubname_param = {
1698			.function = lr->function, .file = lr->file,
1699			.cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1700		struct dwarf_callback_param line_range_param = {
1701			.data = (void *)&lf, .retval = 0};
1702
1703		dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1704				  &pubname_param, 0);
1705		if (pubname_param.found) {
1706			line_range_search_cb(&lf.sp_die, &line_range_param);
1707			if (lf.found)
1708				goto found;
1709		}
1710	}
1711
1712	/* Loop on CUs (Compilation Unit) */
1713	while (!lf.found && ret >= 0) {
1714		if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1715				 NULL, NULL, NULL) != 0)
1716			break;
1717
1718		/* Get the DIE(Debugging Information Entry) of this CU */
1719		diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1720		if (!diep)
 
1721			continue;
 
1722
1723		/* Check if target file is included. */
1724		if (lr->file)
1725			lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1726		else
1727			lf.fname = 0;
1728
1729		if (!lr->file || lf.fname) {
1730			if (lr->function)
1731				ret = find_line_range_by_func(&lf);
1732			else {
1733				lf.lno_s = lr->start;
1734				lf.lno_e = lr->end;
1735				ret = find_line_range_by_line(NULL, &lf);
1736			}
1737		}
1738		off = noff;
1739	}
1740
1741found:
1742	/* Store comp_dir */
1743	if (lf.found) {
1744		comp_dir = cu_get_comp_dir(&lf.cu_die);
1745		if (comp_dir) {
1746			lr->comp_dir = strdup(comp_dir);
1747			if (!lr->comp_dir)
1748				ret = -ENOMEM;
1749		}
1750	}
1751
1752	pr_debug("path: %s\n", lr->path);
1753	return (ret < 0) ? ret : lf.found;
1754}
1755
1756/*
1757 * Find a src file from a DWARF tag path. Prepend optional source path prefix
1758 * and chop off leading directories that do not exist. Result is passed back as
1759 * a newly allocated path on success.
1760 * Return 0 if file was found and readable, -errno otherwise.
1761 */
1762int get_real_path(const char *raw_path, const char *comp_dir,
1763			 char **new_path)
1764{
1765	const char *prefix = symbol_conf.source_prefix;
 
 
 
 
 
1766
1767	if (!prefix) {
1768		if (raw_path[0] != '/' && comp_dir)
1769			/* If not an absolute path, try to use comp_dir */
1770			prefix = comp_dir;
1771		else {
1772			if (access(raw_path, R_OK) == 0) {
1773				*new_path = strdup(raw_path);
1774				return *new_path ? 0 : -ENOMEM;
1775			} else
1776				return -errno;
1777		}
1778	}
1779
1780	*new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1781	if (!*new_path)
1782		return -ENOMEM;
1783
1784	for (;;) {
1785		sprintf(*new_path, "%s/%s", prefix, raw_path);
1786
1787		if (access(*new_path, R_OK) == 0)
1788			return 0;
1789
1790		if (!symbol_conf.source_prefix) {
1791			/* In case of searching comp_dir, don't retry */
1792			zfree(new_path);
1793			return -errno;
1794		}
1795
1796		switch (errno) {
1797		case ENAMETOOLONG:
1798		case ENOENT:
1799		case EROFS:
1800		case EFAULT:
1801			raw_path = strchr(++raw_path, '/');
1802			if (!raw_path) {
1803				zfree(new_path);
1804				return -ENOENT;
1805			}
1806			continue;
1807
1808		default:
1809			zfree(new_path);
1810			return -errno;
1811		}
1812	}
1813}