probe-finder.c 39.6 KB
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/*
 * probe-finder.c : C expression to kprobe event converter
 *
 * Written by Masami Hiramatsu <mhiramat@redhat.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 */

#include <sys/utsname.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
32
#include <dwarf-regs.h>
33

34
#include <linux/bitops.h>
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#include "event.h"
36
#include "dso.h"
37
#include "debug.h"
38
#include "intlist.h"
39
#include "util.h"
40
#include "symbol.h"
41 42
#include "probe-finder.h"

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

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/* Dwarf FL wrappers */
static char *debuginfo_path;	/* Currently dummy */

static const Dwfl_Callbacks offline_callbacks = {
	.find_debuginfo = dwfl_standard_find_debuginfo,
	.debuginfo_path = &debuginfo_path,

	.section_address = dwfl_offline_section_address,

	/* We use this table for core files too.  */
	.find_elf = dwfl_build_id_find_elf,
};

/* Get a Dwarf from offline image */
60
static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
61
					 const char *path)
62
{
63
	int fd;
64

65 66 67
	fd = open(path, O_RDONLY);
	if (fd < 0)
		return fd;
68

69 70
	dbg->dwfl = dwfl_begin(&offline_callbacks);
	if (!dbg->dwfl)
71
		goto error;
72

73 74
	dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
	if (!dbg->mod)
75 76
		goto error;

77 78
	dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
	if (!dbg->dbg)
79 80 81
		goto error;

	return 0;
82
error:
83 84
	if (dbg->dwfl)
		dwfl_end(dbg->dwfl);
85 86
	else
		close(fd);
87
	memset(dbg, 0, sizeof(*dbg));
88 89

	return -ENOENT;
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}

92
static struct debuginfo *__debuginfo__new(const char *path)
93
{
94 95
	struct debuginfo *dbg = zalloc(sizeof(*dbg));
	if (!dbg)
96 97
		return NULL;

98 99
	if (debuginfo__init_offline_dwarf(dbg, path) < 0)
		zfree(&dbg);
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	if (dbg)
		pr_debug("Open Debuginfo file: %s\n", path);
102
	return dbg;
103 104
}

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enum dso_binary_type distro_dwarf_types[] = {
	DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
	DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
	DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
	DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
	DSO_BINARY_TYPE__NOT_FOUND,
};

struct debuginfo *debuginfo__new(const char *path)
{
	enum dso_binary_type *type;
	char buf[PATH_MAX], nil = '\0';
	struct dso *dso;
	struct debuginfo *dinfo = NULL;

	/* Try to open distro debuginfo files */
	dso = dso__new(path);
	if (!dso)
		goto out;

	for (type = distro_dwarf_types;
	     !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND;
	     type++) {
		if (dso__read_binary_type_filename(dso, *type, &nil,
						   buf, PATH_MAX) < 0)
			continue;
		dinfo = __debuginfo__new(buf);
	}
	dso__delete(dso);

out:
	/* if failed to open all distro debuginfo, open given binary */
	return dinfo ? : __debuginfo__new(path);
}

140
void debuginfo__delete(struct debuginfo *dbg)
141
{
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	if (dbg) {
		if (dbg->dwfl)
			dwfl_end(dbg->dwfl);
		free(dbg);
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	}
147
}
148

149 150 151 152
/*
 * Probe finder related functions
 */

153
static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
154
{
155 156
	struct probe_trace_arg_ref *ref;
	ref = zalloc(sizeof(struct probe_trace_arg_ref));
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	if (ref != NULL)
		ref->offset = offs;
	return ref;
}

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/*
 * Convert a location into trace_arg.
 * If tvar == NULL, this just checks variable can be converted.
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 * If fentry == true and vr_die is a parameter, do huristic search
 * for the location fuzzed by function entry mcount.
167 168
 */
static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
169
				     Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
170
				     struct probe_trace_arg *tvar)
171
{
172
	Dwarf_Attribute attr;
173
	Dwarf_Addr tmp = 0;
174 175
	Dwarf_Op *op;
	size_t nops;
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	unsigned int regn;
	Dwarf_Word offs = 0;
178
	bool ref = false;
179
	const char *regs;
180 181
	int ret;

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	if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
		goto static_var;

185
	/* TODO: handle more than 1 exprs */
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	if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
		return -EINVAL;	/* Broken DIE ? */
	if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
		ret = dwarf_entrypc(sp_die, &tmp);
		if (ret || addr != tmp ||
		    dwarf_tag(vr_die) != DW_TAG_formal_parameter ||
		    dwarf_highpc(sp_die, &tmp))
			return -ENOENT;
		/*
		 * This is fuzzed by fentry mcount. We try to find the
		 * parameter location at the earliest address.
		 */
		for (addr += 1; addr <= tmp; addr++) {
			if (dwarf_getlocation_addr(&attr, addr, &op,
						   &nops, 1) > 0)
				goto found;
		}
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		return -ENOENT;
	}
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found:
	if (nops == 0)
		/* TODO: Support const_value */
		return -ENOENT;
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	if (op->atom == DW_OP_addr) {
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static_var:
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		if (!tvar)
			return 0;
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		/* Static variables on memory (not stack), make @varname */
		ret = strlen(dwarf_diename(vr_die));
		tvar->value = zalloc(ret + 2);
		if (tvar->value == NULL)
			return -ENOMEM;
		snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
		tvar->ref = alloc_trace_arg_ref((long)offs);
		if (tvar->ref == NULL)
			return -ENOMEM;
		return 0;
	}
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	/* If this is based on frame buffer, set the offset */
227
	if (op->atom == DW_OP_fbreg) {
228
		if (fb_ops == NULL)
229
			return -ENOTSUP;
230
		ref = true;
231
		offs = op->number;
232
		op = &fb_ops[0];
233
	}
234

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	if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
		regn = op->atom - DW_OP_breg0;
		offs += op->number;
238
		ref = true;
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	} else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
		regn = op->atom - DW_OP_reg0;
	} else if (op->atom == DW_OP_bregx) {
		regn = op->number;
		offs += op->number2;
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		ref = true;
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	} else if (op->atom == DW_OP_regx) {
		regn = op->number;
247
	} else {
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		pr_debug("DW_OP %x is not supported.\n", op->atom);
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		return -ENOTSUP;
	}
251

252 253 254
	if (!tvar)
		return 0;

255
	regs = get_arch_regstr(regn);
256
	if (!regs) {
257
		/* This should be a bug in DWARF or this tool */
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		pr_warning("Mapping for the register number %u "
			   "missing on this architecture.\n", regn);
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		return -ERANGE;
	}
262

263 264 265 266
	tvar->value = strdup(regs);
	if (tvar->value == NULL)
		return -ENOMEM;

267
	if (ref) {
268
		tvar->ref = alloc_trace_arg_ref((long)offs);
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		if (tvar->ref == NULL)
			return -ENOMEM;
271
	}
272
	return 0;
273 274
}

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#define BYTES_TO_BITS(nb)	((nb) * BITS_PER_LONG / sizeof(long))

277
static int convert_variable_type(Dwarf_Die *vr_die,
278
				 struct probe_trace_arg *tvar,
279
				 const char *cast)
280
{
281
	struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
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	Dwarf_Die type;
	char buf[16];
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	char sbuf[STRERR_BUFSIZE];
285
	int bsize, boffs, total;
286 287
	int ret;

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	/* TODO: check all types */
	if (cast && strcmp(cast, "string") != 0) {
		/* Non string type is OK */
		tvar->type = strdup(cast);
		return (tvar->type == NULL) ? -ENOMEM : 0;
	}

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	bsize = dwarf_bitsize(vr_die);
	if (bsize > 0) {
297
		/* This is a bitfield */
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		boffs = dwarf_bitoffset(vr_die);
		total = dwarf_bytesize(vr_die);
		if (boffs < 0 || total < 0)
			return -ENOENT;
		ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
				BYTES_TO_BITS(total));
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		goto formatted;
	}

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	if (die_get_real_type(vr_die, &type) == NULL) {
		pr_warning("Failed to get a type information of %s.\n",
			   dwarf_diename(vr_die));
		return -ENOENT;
	}
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313 314 315
	pr_debug("%s type is %s.\n",
		 dwarf_diename(vr_die), dwarf_diename(&type));

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	if (cast && strcmp(cast, "string") == 0) {	/* String type */
		ret = dwarf_tag(&type);
		if (ret != DW_TAG_pointer_type &&
		    ret != DW_TAG_array_type) {
			pr_warning("Failed to cast into string: "
321
				   "%s(%s) is not a pointer nor array.\n",
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				   dwarf_diename(vr_die), dwarf_diename(&type));
			return -EINVAL;
		}
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		if (die_get_real_type(&type, &type) == NULL) {
			pr_warning("Failed to get a type"
				   " information.\n");
			return -ENOENT;
		}
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		if (ret == DW_TAG_pointer_type) {
			while (*ref_ptr)
				ref_ptr = &(*ref_ptr)->next;
			/* Add new reference with offset +0 */
334
			*ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
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			if (*ref_ptr == NULL) {
				pr_warning("Out of memory error\n");
				return -ENOMEM;
			}
		}
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		if (!die_compare_name(&type, "char") &&
		    !die_compare_name(&type, "unsigned char")) {
342
			pr_warning("Failed to cast into string: "
343
				   "%s is not (unsigned) char *.\n",
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				   dwarf_diename(vr_die));
			return -EINVAL;
		}
		tvar->type = strdup(cast);
		return (tvar->type == NULL) ? -ENOMEM : 0;
	}

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	ret = dwarf_bytesize(&type);
	if (ret <= 0)
353 354
		/* No size ... try to use default type */
		return 0;
355
	ret = BYTES_TO_BITS(ret);
356

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	/* Check the bitwidth */
	if (ret > MAX_BASIC_TYPE_BITS) {
		pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
			dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
		ret = MAX_BASIC_TYPE_BITS;
362
	}
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	ret = snprintf(buf, 16, "%c%d",
		       die_is_signed_type(&type) ? 's' : 'u', ret);

formatted:
	if (ret < 0 || ret >= 16) {
		if (ret >= 16)
			ret = -E2BIG;
		pr_warning("Failed to convert variable type: %s\n",
371
			   strerror_r(-ret, sbuf, sizeof(sbuf)));
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		return ret;
	}
	tvar->type = strdup(buf);
	if (tvar->type == NULL)
		return -ENOMEM;
377
	return 0;
378 379
}

380
static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
381
				    struct perf_probe_arg_field *field,
382
				    struct probe_trace_arg_ref **ref_ptr,
383
				    Dwarf_Die *die_mem)
384
{
385
	struct probe_trace_arg_ref *ref = *ref_ptr;
386 387
	Dwarf_Die type;
	Dwarf_Word offs;
388
	int ret, tag;
389 390

	pr_debug("converting %s in %s\n", field->name, varname);
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	if (die_get_real_type(vr_die, &type) == NULL) {
		pr_warning("Failed to get the type of %s.\n", varname);
		return -ENOENT;
	}
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	pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
	tag = dwarf_tag(&type);

	if (field->name[0] == '[' &&
	    (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
		if (field->next)
			/* Save original type for next field */
			memcpy(die_mem, &type, sizeof(*die_mem));
		/* Get the type of this array */
		if (die_get_real_type(&type, &type) == NULL) {
			pr_warning("Failed to get the type of %s.\n", varname);
			return -ENOENT;
		}
		pr_debug2("Array real type: (%x)\n",
			 (unsigned)dwarf_dieoffset(&type));
		if (tag == DW_TAG_pointer_type) {
411
			ref = zalloc(sizeof(struct probe_trace_arg_ref));
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			if (ref == NULL)
				return -ENOMEM;
			if (*ref_ptr)
				(*ref_ptr)->next = ref;
			else
				*ref_ptr = ref;
		}
419
		ref->offset += dwarf_bytesize(&type) * field->index;
420 421 422 423 424 425
		if (!field->next)
			/* Save vr_die for converting types */
			memcpy(die_mem, vr_die, sizeof(*die_mem));
		goto next;
	} else if (tag == DW_TAG_pointer_type) {
		/* Check the pointer and dereference */
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		if (!field->ref) {
			pr_err("Semantic error: %s must be referred by '->'\n",
			       field->name);
			return -EINVAL;
		}
431
		/* Get the type pointed by this pointer */
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		if (die_get_real_type(&type, &type) == NULL) {
			pr_warning("Failed to get the type of %s.\n", varname);
			return -ENOENT;
		}
436
		/* Verify it is a data structure  */
437 438 439 440
		tag = dwarf_tag(&type);
		if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
			pr_warning("%s is not a data structure nor an union.\n",
				   varname);
441 442
			return -EINVAL;
		}
443

444
		ref = zalloc(sizeof(struct probe_trace_arg_ref));
445 446
		if (ref == NULL)
			return -ENOMEM;
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		if (*ref_ptr)
			(*ref_ptr)->next = ref;
		else
			*ref_ptr = ref;
	} else {
452
		/* Verify it is a data structure  */
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		if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
			pr_warning("%s is not a data structure nor an union.\n",
				   varname);
456 457
			return -EINVAL;
		}
458
		if (field->name[0] == '[') {
459
			pr_err("Semantic error: %s is not a pointer"
460
			       " nor array.\n", varname);
461 462
			return -EINVAL;
		}
463 464 465 466 467 468 469 470 471 472
		if (field->ref) {
			pr_err("Semantic error: %s must be referred by '.'\n",
			       field->name);
			return -EINVAL;
		}
		if (!ref) {
			pr_warning("Structure on a register is not "
				   "supported yet.\n");
			return -ENOTSUP;
		}
473 474
	}

475
	if (die_find_member(&type, field->name, die_mem) == NULL) {
476
		pr_warning("%s(type:%s) has no member %s.\n", varname,
477 478 479
			   dwarf_diename(&type), field->name);
		return -EINVAL;
	}
480 481

	/* Get the offset of the field */
482 483 484 485 486 487 488 489 490
	if (tag == DW_TAG_union_type) {
		offs = 0;
	} else {
		ret = die_get_data_member_location(die_mem, &offs);
		if (ret < 0) {
			pr_warning("Failed to get the offset of %s.\n",
				   field->name);
			return ret;
		}
491
	}
492 493
	ref->offset += (long)offs;

494
next:
495 496
	/* Converting next field */
	if (field->next)
497
		return convert_variable_fields(die_mem, field->name,
498
					field->next, &ref, die_mem);
499 500
	else
		return 0;
501 502
}

503
/* Show a variables in kprobe event format */
504
static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
505
{
506
	Dwarf_Die die_mem;
507 508
	int ret;

509 510
	pr_debug("Converting variable %s into trace event.\n",
		 dwarf_diename(vr_die));
511

512
	ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
513
					&pf->sp_die, pf->tvar);
514
	if (ret == -ENOENT || ret == -EINVAL)
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		pr_err("Failed to find the location of %s at this address.\n"
		       " Perhaps, it has been optimized out.\n", pf->pvar->var);
	else if (ret == -ENOTSUP)
		pr_err("Sorry, we don't support this variable location yet.\n");
519
	else if (ret == 0 && pf->pvar->field) {
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		ret = convert_variable_fields(vr_die, pf->pvar->var,
					      pf->pvar->field, &pf->tvar->ref,
					      &die_mem);
523 524
		vr_die = &die_mem;
	}
525 526
	if (ret == 0)
		ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
527
	/* *expr will be cached in libdw. Don't free it. */
528
	return ret;
529 530
}

531 532
/* Find a variable in a scope DIE */
static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
533
{
534
	Dwarf_Die vr_die;
535
	char buf[32], *ptr;
536
	int ret = 0;
537

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

557
	if (pf->pvar->name)
558
		pf->tvar->name = strdup(pf->pvar->name);
559
	else {
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		ret = synthesize_perf_probe_arg(pf->pvar, buf, 32);
		if (ret < 0)
			return ret;
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		ptr = strchr(buf, ':');	/* Change type separator to _ */
		if (ptr)
			*ptr = '_';
566
		pf->tvar->name = strdup(buf);
567
	}
568 569
	if (pf->tvar->name == NULL)
		return -ENOMEM;
570

571
	pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
572
	/* Search child die for local variables and parameters. */
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	if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
		/* Search again in global variables */
		if (!die_find_variable_at(&pf->cu_die, pf->pvar->var, 0, &vr_die))
576 577
			pr_warning("Failed to find '%s' in this function.\n",
				   pf->pvar->var);
578
			ret = -ENOENT;
579
	}
580
	if (ret >= 0)
581 582
		ret = convert_variable(&vr_die, pf);

583
	return ret;
584 585
}

586
/* Convert subprogram DIE to trace point */
587 588 589
static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
				  Dwarf_Addr paddr, bool retprobe,
				  struct probe_trace_point *tp)
590
{
591
	Dwarf_Addr eaddr, highaddr;
592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611
	GElf_Sym sym;
	const char *symbol;

	/* Verify the address is correct */
	if (dwarf_entrypc(sp_die, &eaddr) != 0) {
		pr_warning("Failed to get entry address of %s\n",
			   dwarf_diename(sp_die));
		return -ENOENT;
	}
	if (dwarf_highpc(sp_die, &highaddr) != 0) {
		pr_warning("Failed to get end address of %s\n",
			   dwarf_diename(sp_die));
		return -ENOENT;
	}
	if (paddr > highaddr) {
		pr_warning("Offset specified is greater than size of %s\n",
			   dwarf_diename(sp_die));
		return -EINVAL;
	}

612
	symbol = dwarf_diename(sp_die);
613
	if (!symbol) {
614 615 616 617 618 619 620 621
		/* Try to get the symbol name from symtab */
		symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
		if (!symbol) {
			pr_warning("Failed to find symbol at 0x%lx\n",
				   (unsigned long)paddr);
			return -ENOENT;
		}
		eaddr = sym.st_value;
622
	}
623
	tp->offset = (unsigned long)(paddr - eaddr);
624
	tp->address = (unsigned long)paddr;
625 626 627
	tp->symbol = strdup(symbol);
	if (!tp->symbol)
		return -ENOMEM;
628

629
	/* Return probe must be on the head of a subprogram */
630 631
	if (retprobe) {
		if (eaddr != paddr) {
632
			pr_warning("Return probe must be on the head of"
633
				   " a real function.\n");
634 635
			return -EINVAL;
		}
636
		tp->retprobe = true;
637 638
	}

639 640 641
	return 0;
}

642 643
/* Call probe_finder callback with scope DIE */
static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
644 645 646 647 648
{
	Dwarf_Attribute fb_attr;
	size_t nops;
	int ret;

649 650 651 652 653 654
	if (!sc_die) {
		pr_err("Caller must pass a scope DIE. Program error.\n");
		return -EINVAL;
	}

	/* If not a real subprogram, find a real one */
655
	if (!die_is_func_def(sc_die)) {
656
		if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
657 658 659 660
			pr_warning("Failed to find probe point in any "
				   "functions.\n");
			return -ENOENT;
		}
661 662
	} else
		memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
663

664 665
	/* Get the frame base attribute/ops from subprogram */
	dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
666
	ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
667
	if (ret <= 0 || nops == 0) {
668
		pf->fb_ops = NULL;
669
#if _ELFUTILS_PREREQ(0, 142)
670 671 672
	} else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
		   pf->cfi != NULL) {
		Dwarf_Frame *frame;
673 674
		if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
		    dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
675
			pr_warning("Failed to get call frame on 0x%jx\n",
676 677 678
				   (uintmax_t)pf->addr);
			return -ENOENT;
		}
679
#endif
680
	}
681

682
	/* Call finder's callback handler */
683
	ret = pf->callback(sc_die, pf);
684 685 686

	/* *pf->fb_ops will be cached in libdw. Don't free it. */
	pf->fb_ops = NULL;
687 688

	return ret;
689 690
}

691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748
struct find_scope_param {
	const char *function;
	const char *file;
	int line;
	int diff;
	Dwarf_Die *die_mem;
	bool found;
};

static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
{
	struct find_scope_param *fsp = data;
	const char *file;
	int lno;

	/* Skip if declared file name does not match */
	if (fsp->file) {
		file = dwarf_decl_file(fn_die);
		if (!file || strcmp(fsp->file, file) != 0)
			return 0;
	}
	/* If the function name is given, that's what user expects */
	if (fsp->function) {
		if (die_compare_name(fn_die, fsp->function)) {
			memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
			fsp->found = true;
			return 1;
		}
	} else {
		/* With the line number, find the nearest declared DIE */
		dwarf_decl_line(fn_die, &lno);
		if (lno < fsp->line && fsp->diff > fsp->line - lno) {
			/* Keep a candidate and continue */
			fsp->diff = fsp->line - lno;
			memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
			fsp->found = true;
		}
	}
	return 0;
}

/* Find an appropriate scope fits to given conditions */
static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
{
	struct find_scope_param fsp = {
		.function = pf->pev->point.function,
		.file = pf->fname,
		.line = pf->lno,
		.diff = INT_MAX,
		.die_mem = die_mem,
		.found = false,
	};

	cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);

	return fsp.found ? die_mem : NULL;
}

749 750
static int probe_point_line_walker(const char *fname, int lineno,
				   Dwarf_Addr addr, void *data)
751
{
752
	struct probe_finder *pf = data;
753
	Dwarf_Die *sc_die, die_mem;
754
	int ret;
755

756 757
	if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
		return 0;
758

759
	pf->addr = addr;
760 761 762 763 764 765 766
	sc_die = find_best_scope(pf, &die_mem);
	if (!sc_die) {
		pr_warning("Failed to find scope of probe point.\n");
		return -ENOENT;
	}

	ret = call_probe_finder(sc_die, pf);
767

768
	/* Continue if no error, because the line will be in inline function */
769
	return ret < 0 ? ret : 0;
770
}
771

772 773 774 775
/* Find probe point from its line number */
static int find_probe_point_by_line(struct probe_finder *pf)
{
	return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
776 777
}

778
/* Find lines which match lazy pattern */
779
static int find_lazy_match_lines(struct intlist *list,
780 781
				 const char *fname, const char *pat)
{
782 783 784 785 786
	FILE *fp;
	char *line = NULL;
	size_t line_len;
	ssize_t len;
	int count = 0, linenum = 1;
787
	char sbuf[STRERR_BUFSIZE];
788 789 790

	fp = fopen(fname, "r");
	if (!fp) {
791 792
		pr_warning("Failed to open %s: %s\n", fname,
			   strerror_r(errno, sbuf, sizeof(sbuf)));
793
		return -errno;
794 795
	}

796
	while ((len = getline(&line, &line_len, fp)) > 0) {
797

798 799 800 801
		if (line[len - 1] == '\n')
			line[len - 1] = '\0';

		if (strlazymatch(line, pat)) {
802
			intlist__add(list, linenum);
803
			count++;
804
		}
805
		linenum++;
806
	}
807 808 809 810 811 812 813 814 815

	if (ferror(fp))
		count = -errno;
	free(line);
	fclose(fp);

	if (count == 0)
		pr_debug("No matched lines found in %s.\n", fname);
	return count;
816 817
}

818 819 820 821
static int probe_point_lazy_walker(const char *fname, int lineno,
				   Dwarf_Addr addr, void *data)
{
	struct probe_finder *pf = data;
822
	Dwarf_Die *sc_die, die_mem;
823 824
	int ret;

825
	if (!intlist__has_entry(pf->lcache, lineno) ||
826 827 828 829 830 831
	    strtailcmp(fname, pf->fname) != 0)
		return 0;

	pr_debug("Probe line found: line:%d addr:0x%llx\n",
		 lineno, (unsigned long long)addr);
	pf->addr = addr;
832 833 834 835 836 837 838 839
	pf->lno = lineno;
	sc_die = find_best_scope(pf, &die_mem);
	if (!sc_die) {
		pr_warning("Failed to find scope of probe point.\n");
		return -ENOENT;
	}

	ret = call_probe_finder(sc_die, pf);
840 841 842 843 844

	/*
	 * Continue if no error, because the lazy pattern will match
	 * to other lines
	 */
845
	return ret < 0 ? ret : 0;
846 847
}

848
/* Find probe points from lazy pattern  */
849
static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
850
{
851
	int ret = 0;
852

853
	if (intlist__empty(pf->lcache)) {
854
		/* Matching lazy line pattern */
855
		ret = find_lazy_match_lines(pf->lcache, pf->fname,
856
					    pf->pev->point.lazy_line);
857
		if (ret <= 0)
858
			return ret;
859 860
	}

861
	return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
862 863
}

864 865
static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
{
866
	struct probe_finder *pf = data;
867
	struct perf_probe_point *pp = &pf->pev->point;
868
	Dwarf_Addr addr;
869
	int ret;
870

871
	if (pp->lazy_line)
872
		ret = find_probe_point_lazy(in_die, pf);
873 874
	else {
		/* Get probe address */
875
		if (dwarf_entrypc(in_die, &addr) != 0) {
876
			pr_warning("Failed to get entry address of %s.\n",
877
				   dwarf_diename(in_die));
878
			return -ENOENT;
879 880
		}
		pf->addr = addr;
881 882 883 884
		pf->addr += pp->offset;
		pr_debug("found inline addr: 0x%jx\n",
			 (uintmax_t)pf->addr);

885
		ret = call_probe_finder(in_die, pf);
886
	}
887

888
	return ret;
889
}
890

891 892 893 894 895 896
/* Callback parameter with return value for libdw */
struct dwarf_callback_param {
	void *data;
	int retval;
};

897
/* Search function from function name */
898
static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
899
{
900 901
	struct dwarf_callback_param *param = data;
	struct probe_finder *pf = param->data;
902
	struct perf_probe_point *pp = &pf->pev->point;
903

904
	/* Check tag and diename */
905 906
	if (!die_is_func_def(sp_die) ||
	    !die_compare_name(sp_die, pp->function))
907
		return DWARF_CB_OK;
908

909 910 911 912
	/* Check declared file */
	if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
		return DWARF_CB_OK;

913
	pf->fname = dwarf_decl_file(sp_die);
914 915 916
	if (pp->line) { /* Function relative line */
		dwarf_decl_line(sp_die, &pf->lno);
		pf->lno += pp->line;
917
		param->retval = find_probe_point_by_line(pf);
918 919
	} else if (!dwarf_func_inline(sp_die)) {
		/* Real function */
920
		if (pp->lazy_line)
921
			param->retval = find_probe_point_lazy(sp_die, pf);
922
		else {
923
			if (dwarf_entrypc(sp_die, &pf->addr) != 0) {
924 925
				pr_warning("Failed to get entry address of "
					   "%s.\n", dwarf_diename(sp_die));
926 927 928
				param->retval = -ENOENT;
				return DWARF_CB_ABORT;
			}
929 930
			pf->addr += pp->offset;
			/* TODO: Check the address in this function */
931
			param->retval = call_probe_finder(sp_die, pf);
932
		}
933
	} else
934
		/* Inlined function: search instances */
935 936
		param->retval = die_walk_instances(sp_die,
					probe_point_inline_cb, (void *)pf);
937

938
	return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
939 940
}

941
static int find_probe_point_by_func</