probe-finder.c 44.6 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

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	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
	dwfl_report_begin(dbg->dwfl);
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	dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
	if (!dbg->mod)
76 77
		goto error;

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

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	dwfl_report_end(dbg->dwfl, NULL, NULL);

84
	return 0;
85
error:
86 87
	if (dbg->dwfl)
		dwfl_end(dbg->dwfl);
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	else
		close(fd);
90
	memset(dbg, 0, sizeof(*dbg));
91 92

	return -ENOENT;
93 94
}

95
static struct debuginfo *__debuginfo__new(const char *path)
96
{
97 98
	struct debuginfo *dbg = zalloc(sizeof(*dbg));
	if (!dbg)
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		return NULL;

101 102
	if (debuginfo__init_offline_dwarf(dbg, path) < 0)
		zfree(&dbg);
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	if (dbg)
		pr_debug("Open Debuginfo file: %s\n", path);
105
	return dbg;
106 107
}

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

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void debuginfo__delete(struct debuginfo *dbg)
144
{
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	if (dbg) {
		if (dbg->dwfl)
			dwfl_end(dbg->dwfl);
		free(dbg);
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	}
150
}
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/*
 * Probe finder related functions
 */

156
static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
157
{
158 159
	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.
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 */
static 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;
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	Dwarf_Op *op;
	size_t nops;
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	unsigned int regn;
	Dwarf_Word offs = 0;
181
	bool ref = false;
182
	const char *regs;
183
	int ret, ret2 = 0;
184

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

188
	/* 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);
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		if (ret)
			return -ENOENT;

		if (probe_conf.show_location_range &&
			(dwarf_tag(vr_die) == DW_TAG_variable)) {
			ret2 = -ERANGE;
		} else if (addr != tmp ||
			dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
			return -ENOENT;
		}

		ret = dwarf_highpc(sp_die, &tmp);
		if (ret)
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			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)
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			return ret2;
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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;
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		return ret2;
237
	}
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	/* 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;
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		op = &fb_ops[0];
246
	}
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	if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
		regn = op->atom - DW_OP_breg0;
		offs += op->number;
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		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;
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	} else {
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		pr_debug("DW_OP %x is not supported.\n", op->atom);
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		return -ENOTSUP;
	}
264

265
	if (!tvar)
266
		return ret2;
267

268
	regs = get_arch_regstr(regn);
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	if (!regs) {
270
		/* This should be a bug in DWARF or this tool */
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Masami Hiramatsu 已提交
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		pr_warning("Mapping for the register number %u "
			   "missing on this architecture.\n", regn);
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		return -ENOTSUP;
274
	}
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	tvar->value = strdup(regs);
	if (tvar->value == NULL)
		return -ENOMEM;

280
	if (ref) {
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		tvar->ref = alloc_trace_arg_ref((long)offs);
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		if (tvar->ref == NULL)
			return -ENOMEM;
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	}
285
	return ret2;
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}

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

290
static 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;
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	Dwarf_Die type;
	char buf[16];
297
	char sbuf[STRERR_BUFSIZE];
298
	int bsize, boffs, total;
299 300
	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) {
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		/* 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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326 327 328
	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: "
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Masami Hiramatsu 已提交
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				   "%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 */
347
			*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")) {
355
			pr_warning("Failed to cast into string: "
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Masami Hiramatsu 已提交
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				   "%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)
366 367
		/* No size ... try to use default type */
		return 0;
368
	ret = BYTES_TO_BITS(ret);
369

370 371 372 373 374
	/* 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;
375
	}
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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",
384
			   strerror_r(-ret, sbuf, sizeof(sbuf)));
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		return ret;
	}
	tvar->type = strdup(buf);
	if (tvar->type == NULL)
		return -ENOMEM;
390
	return 0;
391 392
}

393
static 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;
399 400
	Dwarf_Die type;
	Dwarf_Word offs;
401
	int ret, tag;
402 403

	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) {
424
			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;
		}
432
		ref->offset += dwarf_bytesize(&type) * field->index;
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		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 */
439 440 441 442 443
		if (!field->ref) {
			pr_err("Semantic error: %s must be referred by '->'\n",
			       field->name);
			return -EINVAL;
		}
444
		/* Get the type pointed by this pointer */
445 446 447 448
		if (die_get_real_type(&type, &type) == NULL) {
			pr_warning("Failed to get the type of %s.\n", varname);
			return -ENOENT;
		}
449
		/* Verify it is a data structure  */
450 451 452 453
		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);
454 455
			return -EINVAL;
		}
456

457
		ref = zalloc(sizeof(struct probe_trace_arg_ref));
458 459
		if (ref == NULL)
			return -ENOMEM;
460 461 462 463 464
		if (*ref_ptr)
			(*ref_ptr)->next = ref;
		else
			*ref_ptr = ref;
	} else {
465
		/* 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);
469 470
			return -EINVAL;
		}
471
		if (field->name[0] == '[') {
472
			pr_err("Semantic error: %s is not a pointer"
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Masami Hiramatsu 已提交
473
			       " nor array.\n", varname);
474 475
			return -EINVAL;
		}
476 477
		/* While prcessing unnamed field, we don't care about this */
		if (field->ref && dwarf_diename(vr_die)) {
478 479 480 481 482 483 484 485 486
			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;
		}
487 488
	}

489
	if (die_find_member(&type, field->name, die_mem) == NULL) {
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Arnaldo Carvalho de Melo 已提交
490
		pr_warning("%s(type:%s) has no member %s.\n", varname,
491 492 493
			   dwarf_diename(&type), field->name);
		return -EINVAL;
	}
494 495

	/* Get the offset of the field */
496 497 498 499 500 501 502 503 504
	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;
		}
505
	}
506 507
	ref->offset += (long)offs;

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	/* If this member is unnamed, we need to reuse this field */
	if (!dwarf_diename(die_mem))
		return convert_variable_fields(die_mem, varname, field,
						&ref, die_mem);

513
next:
514 515
	/* Converting next field */
	if (field->next)
516
		return convert_variable_fields(die_mem, field->name,
517
					field->next, &ref, die_mem);
518 519
	else
		return 0;
520 521
}

522
/* Show a variables in kprobe event format */
523
static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
524
{
525
	Dwarf_Die die_mem;
526 527
	int ret;

528 529
	pr_debug("Converting variable %s into trace event.\n",
		 dwarf_diename(vr_die));
530

531
	ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
532
					&pf->sp_die, pf->tvar);
533 534 535 536 537 538
	if (ret == -ENOENT || ret == -EINVAL) {
		pr_err("Failed to find the location of the '%s' variable at this address.\n"
		       " Perhaps it has been optimized out.\n"
		       " Use -V with the --range option to show '%s' location range.\n",
		       pf->pvar->var, pf->pvar->var);
	} 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) {
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		ret = convert_variable_fields(vr_die, pf->pvar->var,
					      pf->pvar->field, &pf->tvar->ref,
					      &die_mem);
544 545
		vr_die = &die_mem;
	}
546 547
	if (ret == 0)
		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
}

552 553
/* Find a variable in a scope DIE */
static 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

559 560 561
	/* Copy raw parameters */
	if (!is_c_varname(pf->pvar->var))
		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 {
566 567 568
		ret = synthesize_perf_probe_arg(pf->pvar, buf, 32);
		if (ret < 0)
			return ret;
569 570 571
		ptr = strchr(buf, ':');	/* Change type separator to _ */
		if (ptr)
			*ptr = '_';
572
		pf->tvar->name = strdup(buf);
573
	}
574 575
	if (pf->tvar->name == NULL)
		return -ENOMEM;
576

577
	pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
578
	/* Search child die for local variables and parameters. */
579 580
	if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
		/* Search again in global variables */
581 582
		if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
						0, &vr_die)) {
583 584
			pr_warning("Failed to find '%s' in this function.\n",
				   pf->pvar->var);
585
			ret = -ENOENT;
586
		}
587
	}
588
	if (ret >= 0)
589 590
		ret = convert_variable(&vr_die, pf);

591
	return ret;
592 593
}

594
/* Convert subprogram DIE to trace point */
595 596
static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
				  Dwarf_Addr paddr, bool retprobe,
597
				  const char *function,
598
				  struct probe_trace_point *tp)
599
{
600
	Dwarf_Addr eaddr, highaddr;
601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620
	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;
	}

621
	symbol = dwarf_diename(sp_die);
622
	if (!symbol) {
623 624 625 626 627 628 629 630
		/* 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;
631
	}
632
	tp->offset = (unsigned long)(paddr - eaddr);
633
	tp->address = (unsigned long)paddr;
634 635 636
	tp->symbol = strdup(symbol);
	if (!tp->symbol)
		return -ENOMEM;
637

638
	/* Return probe must be on the head of a subprogram */
639 640
	if (retprobe) {
		if (eaddr != paddr) {
641 642 643 644
			pr_warning("Failed to find \"%s%%return\",\n"
				   " because %s is an inlined function and"
				   " has no return point.\n", function,
				   function);
645 646
			return -EINVAL;
		}
647
		tp->retprobe = true;
648 649
	}

650 651 652
	return 0;
}

653 654
/* Call probe_finder callback with scope DIE */
static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
655 656
{
	Dwarf_Attribute fb_attr;
657
	Dwarf_Frame *frame = NULL;
658 659 660
	size_t nops;
	int ret;

661 662 663 664 665 666
	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 */
667
	if (!die_is_func_def(sc_die)) {
668
		if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
669 670 671 672 673 674 675 676 677
			if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
				pr_warning("Ignoring tail call from %s\n",
						dwarf_diename(&pf->sp_die));
				return 0;
			} else {
				pr_warning("Failed to find probe point in any "
					   "functions.\n");
				return -ENOENT;
			}
678
		}
679 680
	} else
		memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
681

682 683
	/* Get the frame base attribute/ops from subprogram */
	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 &&
689 690 691
		   (pf->cfi_eh != NULL || pf->cfi_dbg != NULL)) {
		if ((dwarf_cfi_addrframe(pf->cfi_eh, pf->addr, &frame) != 0 &&
		     (dwarf_cfi_addrframe(pf->cfi_dbg, pf->addr, &frame) != 0)) ||
692
		    dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
M
Masami Hiramatsu 已提交
693
			pr_warning("Failed to get call frame on 0x%jx\n",
694
				   (uintmax_t)pf->addr);
695 696
			free(frame);
			return -ENOENT;
697
		}
698
#endif
699
	}
700

701
	/* Call finder's callback handler */
702
	ret = pf->callback(sc_die, pf);
703

704 705
	/* Since *pf->fb_ops can be a part of frame. we should free it here. */
	free(frame);
706
	pf->fb_ops = NULL;
707 708

	return ret;
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
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) {
734
		if (die_match_name(fn_die, fsp->function)) {
735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768
			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;
}

769 770
static int probe_point_line_walker(const char *fname, int lineno,
				   Dwarf_Addr addr, void *data)
771
{
772
	struct probe_finder *pf = data;
773
	Dwarf_Die *sc_die, die_mem;
774
	int ret;
775

776 777
	if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
		return 0;
778

779
	pf->addr = addr;
780 781 782 783 784 785 786
	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);
787

788
	/* Continue if no error, because the line will be in inline function */
789
	return ret < 0 ? ret : 0;
790
}
791

792 793 794 795
/* 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);
796 797
}

798
/* Find lines which match lazy pattern */
799
static int find_lazy_match_lines(struct intlist *list,
800 801
				 const char *fname, const char *pat)
{
802 803 804 805 806
	FILE *fp;
	char *line = NULL;
	size_t line_len;
	ssize_t len;
	int count = 0, linenum = 1;
807
	char sbuf[STRERR_BUFSIZE];
808 809 810

	fp = fopen(fname, "r");
	if (!fp) {
811 812
		pr_warning("Failed to open %s: %s\n", fname,
			   strerror_r(errno, sbuf, sizeof(sbuf)));
813
		return -errno;
814 815
	}

816
	while ((len = getline(&line, &line_len, fp)) > 0) {
817

818 819 820 821
		if (line[len - 1] == '\n')
			line[len - 1] = '\0';

		if (strlazymatch(line, pat)) {
822
			intlist__add(list, linenum);
823
			count++;
824
		}
825
		linenum++;
826
	}
827 828 829 830 831 832 833 834 835

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

	if (count == 0)
		pr_debug("No matched lines found in %s.\n", fname);
	return count;
836 837
}

838 839 840 841
static int probe_point_lazy_walker(const char *fname, int lineno,
				   Dwarf_Addr addr, void *data)
{
	struct probe_finder *pf = data;
842
	Dwarf_Die *sc_die, die_mem;
843 844
	int ret;

845
	if (!intlist__has_entry(pf->lcache, lineno) ||
846 847 848 849 850 851
	    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;
852 853 854 855 856 857 858 859
	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);
860 861 862 863 864

	/*
	 * Continue if no error, because the lazy pattern will match
	 * to other lines
	 */
865
	return ret < 0 ? ret : 0;
866 867
}

868
/* Find probe points from lazy pattern  */
869
static 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)) {
875 876 877 878 879 880 881 882 883
		const char *comp_dir;

		comp_dir = cu_get_comp_dir(&pf->cu_die);
		ret = get_real_path(pf->fname, comp_dir, &fpath);
		if (ret < 0) {
			pr_warning("Failed to find source file path.\n");
			return ret;
		}

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
}

895 896
static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
{
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);
904 905
	else {
		/* Get probe address */
906
		if (dwarf_entrypc(in_die, &addr) != 0) {
M
Masami Hiramatsu 已提交
907
			pr_warning("Failed to get entry address of %s.\n",
908
				   dwarf_diename(in_die));
909
			return -ENOENT;
910 911
		}
		pf->addr = addr;
912 913 914 915
		pf->addr += pp->offset;
		pr_debug("found inline addr: 0x%jx\n",
			 (uintmax_t)pf->addr);

916
		ret = call_probe_finder(in_die, pf);
917
	}
918

919
	return ret;
920
}
921

922 923 924 925 926 927
/* Callback parameter with return value for libdw */
struct dwarf_callback_param {
	void *data;
	int retval;
};

928
/* Search function from function name */
929
static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
930
{
931 932
	struct dwarf_callback_param *param = data;
	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

940 941 942 943
	/* Check declared file */
	if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
		return DWARF_CB_OK;

944
	pr_debug("Matched function: %s\n", dwarf_diename(sp_die));
945
	pf->fname = dwarf_decl_file(sp_die);
946 947 948
	if (pp->line) { /* Function relative line */
		dwarf_decl_line(sp_die, &pf->lno);
		pf->lno += pp->line;
949
		param->retval = find_probe_point_by_line(pf);
950 951 952
	} else if (die_is_func_instance(sp_die)) {
		/* Instances always have the entry address */
		dwarf_entrypc(sp_die, &pf->addr);
953
		/* Real function */
954
		if (pp->lazy_line)
955
			param->retval = find_probe_point_lazy(sp_die, pf);
956 957 958
		else {
			pf->addr += pp->offset;
			/* 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 */
963 964
		param->retval = die_walk_instances(sp_die,
					probe_point_inline_cb, (void *)pf);
965 966 967 968 969 970 971 972 973 974
		/* This could be a non-existed inline definition */
		if (param->retval == -ENOENT && strisglob(pp->function))
			param->retval = 0;
	}

	/* We need to find other candidates */
	if (strisglob(pp->function) && param->retval >= 0) {
		param->retval = 0;	/* We have to clear the result */
		return DWARF_CB_OK;
	}
975

976
	return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
977 978
}

979
static int find_probe_point_by_func(struct probe_finder *pf)
980
{
981 982 983 984
	struct dwarf_callback_param _param = {.data = (void *)pf,
					      .retval = 0};
	dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
	return _param.retval;
985 986
}

987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002
struct pubname_callback_param {
	char *function;
	char *file;
	Dwarf_Die *cu_die;
	Dwarf_Die *sp_die;
	int found;
};

static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
{
	struct pubname_callback_param *param = data;

	if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
		if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
			return DWARF_CB_OK;

1003
		if (die_match_name(param->sp_die, param->function)) {
1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018
			if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
				return DWARF_CB_OK;

			if (param->file &&
			    strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
				return DWARF_CB_OK;

			param->found = 1;
			return DWARF_CB_ABORT;
		}
	}

	return DWARF_CB_OK;
}

1019
static int debuginfo__find_probe_location(struct debuginfo *dbg,
1020
				  struct probe_finder *pf)
1021
{
1022
	struct perf_probe_point *pp = &pf->pev->point;
1023 1024 1025
	Dwarf_Off off, noff;
	size_t cuhl;
	Dwarf_Die *diep;
1026
	int ret = 0;
1027 1028

	off = 0;
1029 1030 1031
	pf->lcache = intlist__new(NULL);
	if (!pf->lcache)
		return -ENOMEM;
1032 1033

	/* Fastpath: lookup by function name from .debug_pubnames section */
1034
	if (pp->function && !strisglob(pp->function)) {
1035 1036 1037 1038 1039
		struct pubname_callback_param pubname_param = {
			.function = pp->function,
			.file	  = pp->file,
			.cu_die	  = &pf->cu_die,
			.sp_die	  = &pf->sp_die,
1040
			.found	  = 0,
1041 1042 1043 1044 1045
		};
		struct dwarf_callback_param probe_param = {
			.data = pf,
		};

1046
		dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1047
				  &pubname_param, 0);
1048 1049 1050 1051 1052 1053 1054
		if (pubname_param.found) {
			ret = probe_point_search_cb(&pf->sp_die, &probe_param);
			if (ret)
				goto found;
		}
	}

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 1060
		if (!diep)
			continue;
1061 1062 1063

		/* Check if target file is included. */
		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 1075
				pf->lno = pp->line;
				ret = find_probe_point_by_line(pf);
1076
			}
1077
			if (ret < 0)
1078
				break;
1079
		}
1080
		off = noff;
1081
	}
1082 1083

found:
1084 1085
	intlist__delete(pf->lcache);
	pf->lcache = NULL;
1086

1087 1088 1089
	return ret;
}

1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122
/* Find probe points from debuginfo */
static int debuginfo__find_probes(struct debuginfo *dbg,
				  struct probe_finder *pf)
{
	int ret = 0;

#if _ELFUTILS_PREREQ(0, 142)
	Elf *elf;
	GElf_Ehdr ehdr;
	GElf_Shdr shdr;

	if (pf->cfi_eh || pf->cfi_dbg)
		return debuginfo__find_probe_location(dbg, pf);

	/* Get the call frame information from this dwarf */
	elf = dwarf_getelf(dbg->dbg);
	if (elf == NULL)
		return -EINVAL;

	if (gelf_getehdr(elf, &ehdr) == NULL)
		return -EINVAL;

	if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
	    shdr.sh_type == SHT_PROGBITS)
		pf->cfi_eh = dwarf_getcfi_elf(elf);

	pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
#endif

	ret = debuginfo__find_probe_location(dbg, pf);
	return ret;
}

1123 1124 1125
struct local_vars_finder {
	struct probe_finder *pf;
	struct perf_probe_arg *args;
1126
	bool vars;
1127 1128 1129 1130 1131 1132 1133 1134 1135
	int max_args;
	int nargs;
	int ret;
};

/* Collect available variables in this scope */
static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
{
	struct local_vars_finder *vf = data;
1136
	struct probe_finder *pf = vf->pf;
1137 1138 1139 1140
	int tag;

	tag = dwarf_tag(die_mem);
	if (tag == DW_TAG_formal_parameter ||
1141
	    (tag == DW_TAG_variable && vf->vars)) {
1142
		if (convert_variable_location(die_mem, vf->pf->addr,
1143 1144
					      vf->pf->fb_ops, &pf->sp_die,
					      NULL) == 0) {
1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166
			vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
			if (vf->args[vf->nargs].var == NULL) {
				vf->ret = -ENOMEM;
				return DIE_FIND_CB_END;
			}
			pr_debug(" %s", vf->args[vf->nargs].var);
			vf->nargs++;
		}
	}

	if (dwarf_haspc(die_mem, vf->pf->addr))
		return DIE_FIND_CB_CONTINUE;
	else
		return DIE_FIND_CB_SIBLING;
}

static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
			     struct perf_probe_arg *args)
{
	Dwarf_Die die_mem;
	int i;
	int n = 0;
1167
	struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1168 1169 1170 1171
				.max_args = MAX_PROBE_ARGS, .ret = 0};

	for (i = 0; i < pf->pev->nargs; i++) {
		/* var never be NULL */
1172 1173 1174
		if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
			vf.vars = true;
		else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1175 1176 1177
			/* Copy normal argument */
			args[n] = pf->pev->args[i];
			n++;
1178
			continue;
1179
		}
1180 1181 1182 1183 1184 1185 1186 1187 1188
		pr_debug("Expanding %s into:", pf->pev->args[i].var);
		vf.nargs = n;
		/* Special local variables */
		die_find_child(sc_die, copy_variables_cb, (void *)&vf,
			       &die_mem);
		pr_debug(" (%d)\n", vf.nargs - n);
		if (vf.ret < 0)
			return vf.ret;
		n = vf.nargs;
1189 1190 1191 1192
	}
	return n;
}

1193
/* Add a found probe point into trace event list */
1194
static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1195 1196 1197
{
	struct trace_event_finder *tf =
			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 1202 1203 1204 1205 1206 1207 1208 1209 1210
	int ret, i;

	/* Check number of tevs */
	if (tf->ntevs == tf->max_tevs) {
		pr_warning("Too many( > %d) probe point found.\n",
			   tf->max_tevs);
		return -ERANGE;
	}
	tev = &tf->tevs[tf->ntevs++];

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 1219 1220 1221
	if (!tev->point.realname) {
		ret = -ENOMEM;
		goto end;
	}
1222

1223 1224 1225
	pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
		 tev->point.offset);

1226 1227
	/* Expand special probe argument if exist */
	args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1228 1229 1230 1231
	if (args == NULL) {
		ret = -ENOMEM;
		goto end;
	}
1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246

	ret = expand_probe_args(sc_die, pf, args);
	if (ret < 0)
		goto end;

	tev->nargs = ret;
	tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
	if (tev->args == NULL) {
		ret = -ENOMEM;
		goto end;
	}

	/* Find each argument */
	for (i = 0; i < tev->nargs; i++) {
		pf->pvar = &args[i];
1247
		pf->tvar = &tev->args[i];
1248 1249
		/* Variable should be found from scope DIE */
		ret = find_variable(sc_die, pf);
1250
		if (ret != 0)
1251
			break;
1252 1253
	}

1254
end:
1255 1256 1257 1258
	if (ret) {
		clear_probe_trace_event(tev);
		tf->ntevs--;
	}
1259 1260
	free(args);
	return ret;
1261 1262 1263
}

/* Find probe_trace_events specified by perf_probe_event from debuginfo */
1264
int debuginfo__find_trace_events(struct debuginfo *dbg,
1265
				 struct perf_probe_event *pev,
1266
				 struct probe_trace_event **tevs)
1267 1268 1269
{
	struct trace_event_finder tf = {
			.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 1276 1277 1278 1279 1280
	if (*tevs == NULL)
		return -ENOMEM;

	tf.tevs = *tevs;
	tf.ntevs = 0;

1281
	ret = debuginfo__find_probes(dbg, &tf.pf);
1282
	if (ret < 0) {
1283 1284
		for (i = 0; i < tf.ntevs; i++)
			clear_probe_trace_event(&tf.tevs[i]);
1285
		zfree(tevs);
1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304
		return ret;
	}

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

/* Collect available variables in this scope */
static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
{
	struct available_var_finder *af = data;
	struct variable_list *vl;
	int tag, ret;

	vl = &af->vls[af->nvls - 1];

	tag = dwarf_tag(die_mem);
	if (tag == DW_TAG_formal_parameter ||
	    tag == DW_TAG_variable) {
		ret = convert_variable_location(die_mem, af->pf.addr,
1305 1306
						af->pf.fb_ops, &af->pf.sp_die,
						NULL);
1307 1308 1309
		if (ret == 0 || ret == -ERANGE) {
			int ret2;
			bool externs = !af->child;
1310 1311 1312
			struct strbuf buf;

			strbuf_init(&buf, 64);
1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334

			if (probe_conf.show_location_range) {
				if (!externs) {
					if (ret)
						strbuf_addf(&buf, "[INV]\t");
					else
						strbuf_addf(&buf, "[VAL]\t");
				} else
					strbuf_addf(&buf, "[EXT]\t");
			}

			ret2 = die_get_varname(die_mem, &buf);

			if (!ret2 && probe_conf.show_location_range &&
				!externs) {
				strbuf_addf(&buf, "\t");
				ret2 = die_get_var_range(&af->pf.sp_die,
							die_mem, &buf);
			}

			pr_debug("Add new var: %s\n", buf.buf);
			if (ret2 == 0) {
1335 1336 1337 1338
				strlist__add(vl->vars,
					strbuf_detach(&buf, NULL));
			}
			strbuf_release(&buf);
1339 1340 1341
		}
	}

1342
	if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1343 1344 1345 1346 1347 1348
		return DIE_FIND_CB_CONTINUE;
	else
		return DIE_FIND_CB_SIBLING;
}

/* Add a found vars into available variables list */
1349
static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1350 1351 1352
{
	struct available_var_finder *af =
			container_of(pf, struct available_var_finder, pf);
1353
	struct perf_probe_point *pp = &pf->pev->point;
1354
	struct variable_list *vl;
1355 1356
	Dwarf_Die die_mem;
	int ret;
1357 1358 1359 1360 1361 1362 1363 1364

	/* Check number of tevs */
	if (af->nvls == af->max_vls) {
		pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
		return -ERANGE;
	}
	vl = &af->vls[af->nvls++];

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 1369 1370 1371 1372 1373 1374
	if (ret < 0)
		return ret;

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

	/* Find local variables */
1375
	vl->vars = strlist__new(NULL, NULL);
1376 1377
	if (vl->vars == NULL)
		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 1388

out:
1389 1390 1391 1392 1393 1394 1395 1396
	if (strlist__empty(vl->vars)) {
		strlist__delete(vl->vars);
		vl->vars = NULL;
	}

	return ret;
}

1397 1398 1399 1400 1401
/*
 * Find available variables at given probe point
 * Return the number of found probe points. Return 0 if there is no
 * matched probe point. Return <0 if an error occurs.
 */
1402
int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1403
				      struct perf_probe_event *pev,
1404
				      struct variable_list **vls)
1405 1406 1407
{
	struct available_var_finder af = {
			.pf = {.pev = pev, .callback = add_available_vars},
1408
			.mod = dbg->mod,
1409
			.max_vls = probe_conf.max_probes};
1410 1411 1412
	int ret;

	/* Allocate result vls array */
1413
	*vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1414 1415 1416 1417 1418 1419
	if (*vls == NULL)
		return -ENOMEM;

	af.vls = *vls;
	af.nvls = 0;

1420
	ret = debuginfo__find_probes(dbg, &af.pf);
1421 1422 1423
	if (ret < 0) {
		/* Free vlist for error */
		while (af.nvls--) {
1424
			zfree(&af.vls[af.nvls].point.symbol);
1425
			strlist__delete(af.vls[af.nvls].vars);
1426
		}
1427
		zfree(vls);
1428 1429 1430 1431
		return ret;
	}

	return (ret < 0) ? ret : af.nvls;
1432 1433
}

1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468
/* For the kernel module, we need a special code to get a DIE */
static int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs)
{
	int n, i;
	Elf32_Word shndx;
	Elf_Scn *scn;
	Elf *elf;
	GElf_Shdr mem, *shdr;
	const char *p;

	elf = dwfl_module_getelf(dbg->mod, &dbg->bias);
	if (!elf)
		return -EINVAL;

	/* Get the number of relocations */
	n = dwfl_module_relocations(dbg->mod);
	if (n < 0)
		return -ENOENT;
	/* Search the relocation related .text section */
	for (i = 0; i < n; i++) {
		p = dwfl_module_relocation_info(dbg->mod, i, &shndx);
		if (strcmp(p, ".text") == 0) {
			/* OK, get the section header */
			scn = elf_getscn(elf, shndx);
			if (!scn)
				return -ENOENT;
			shdr = gelf_getshdr(scn, &mem);
			if (!shdr)
				return -ENOENT;
			*offs = shdr->sh_addr;
		}
	}
	return 0;
}

1469
/* Reverse search */
1470
int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1471
				struct perf_probe_point *ppt)
1472 1473
{
	Dwarf_Die cudie, spdie, indie;
1474 1475
	Dwarf_Addr _addr = 0, baseaddr = 0;
	const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1476
	int baseline = 0, lineno = 0, ret = 0;
1477
	bool reloc = false;
1478

1479
retry:
1480
	/* Find cu die */
1481
	if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1482 1483 1484 1485 1486
		if (!reloc && debuginfo__get_text_offset(dbg, &baseaddr) == 0) {
			addr += baseaddr;
			reloc = true;
			goto retry;
		}
M
Masami Hiramatsu 已提交
1487 1488
		pr_warning("Failed to find debug information for address %lx\n",
			   addr);
1489 1490 1491
		ret = -EINVAL;
		goto end;
	}
1492

1493 1494 1495
	/* Find a corresponding line (filename and lineno) */
	cu_find_lineinfo(&cudie, addr, &fname, &lineno);
	/* 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 1501
		func = basefunc = dwarf_diename(&spdie);
		if (!func ||
1502
		    dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1503 1504
		    dwarf_decl_line(&spdie, &baseline) != 0) {
			lineno = 0;
1505
			goto post;
1506
		}
1507

1508
		fname = dwarf_decl_file(&spdie);
1509
		if (addr == (unsigned long)baseaddr) {
1510 1511
			/* Function entry - Relative line number is 0 */
			lineno = baseline;
1512 1513 1514 1515 1516 1517 1518
			goto post;
		}

		/* Track down the inline functions step by step */
		while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
						&indie)) {
			/* There is an inline function */
1519
			if (dwarf_entrypc(&indie, &_addr) == 0 &&
1520
			    _addr == addr) {
1521 1522 1523
				/*
				 * addr is at an inline function entry.
				 * In this case, lineno should be the call-site
1524
				 * line number. (overwrite lineinfo)
1525 1526
				 */
				lineno = die_get_call_lineno(&indie);
1527 1528 1529
				fname = die_get_call_file(&indie);
				break;
			} else {
1530 1531 1532 1533 1534 1535
				/*
				 * addr is in an inline function body.
				 * Since lineno points one of the lines
				 * of the inline function, baseline should
				 * be the entry line of the inline function.
				 */
1536
				tmp = dwarf_diename(&indie);
1537 1538 1539 1540 1541
				if (!tmp ||
				    dwarf_decl_line(&indie, &baseline) != 0)
					break;
				func = tmp;
				spdie = indie;
1542
			}
1543
		}
1544 1545 1546 1547
		/* Verify the lineno and baseline are in a same file */
		tmp = dwarf_decl_file(&spdie);
		if (!tmp || strcmp(tmp, fname) != 0)
			lineno = 0;
1548 1549 1550 1551 1552 1553
	}

post:
	/* Make a relative line number or an offset */
	if (lineno)
		ppt->line = lineno - baseline;
1554
	else if (basefunc) {
1555
		ppt->offset = addr - (unsigned long)baseaddr;
1556 1557
		func = basefunc;
	}
1558 1559 1560 1561

	/* Duplicate strings */
	if (func) {
		ppt->function = strdup(func);
1562 1563 1564 1565
		if (ppt->function == NULL) {
			ret = -ENOMEM;
			goto end;
		}
1566
	}
1567 1568 1569
	if (fname) {
		ppt->file = strdup(fname);
		if (ppt->file == NULL) {
1570
			zfree(&ppt->function);
1571 1572 1573 1574
			ret = -ENOMEM;
			goto end;
		}
	}
1575
end:
1576 1577
	if (ret == 0 && (fname || func))
		ret = 1;	/* Found a point */
1578 1579 1580
	return ret;
}

1581 1582 1583 1584
/* Add a line and store the src path */
static int line_range_add_line(const char *src, unsigned int lineno,
			       struct line_range *lr)
{
1585
	/* Copy source path */
1586
	if (!lr->path) {
1587 1588 1589
		lr->path = strdup(src);
		if (lr->path == NULL)
			return -ENOMEM;
1590
	}
1591
	return intlist__add(lr->line_list, lineno);
1592 1593
}

1594
static 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 1606 1607
	err = line_range_add_line(fname, lineno, lf->lr);
	if (err < 0 && err != -EEXIST)
		return err;
1608

1609
	return 0;
1610
}
1611

1612
/* Find line range from its line number */
1613
static 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 1623 1624
			ret = lf->found = 1;
		else
			ret = 0;	/* Lines are not found */
1625
	else {
1626
		zfree(&lf->lr->path);
1627
	}
1628
	return ret;
1629 1630
}

1631 1632
static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
{
1633
	int ret = find_line_range_by_line(in_die, data);
1634 1635 1636 1637

	/*
	 * We have to check all instances of inlined function, because
	 * some execution paths can be optimized out depends on the
1638 1639
	 * function argument of instances. However, if an error occurs,
	 * it should be handled by the caller.
1640
	 */
1641
	return ret < 0 ? ret : 0;
1642 1643
}

1644
/* Search function definition from function name */
1645
static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1646
{
1647 1648
	struct dwarf_callback_param *param = data;
	struct line_finder *lf = param->data;
1649 1650
	struct line_range *lr = lf->lr;

1651 1652 1653 1654
	/* Check declared file */
	if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
		return DWARF_CB_OK;

1655
	if (die_is_func_def(sp_die) &&
1656
	    die_match_name(sp_die, lr->function)) {
1657 1658
		lf->fname = dwarf_decl_file(sp_die);
		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 1662 1663 1664
		if (lf->lno_s < 0)	/* Overflow */
			lf->lno_s = INT_MAX;
		lf->lno_e = lr->offset + lr->end;
		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 1668
		lr->start = lf->lno_s;
		lr->end = lf->lno_e;
1669
		if (!die_is_func_instance(sp_die))
1670 1671 1672
			param->retval = die_walk_instances(sp_die,
						line_range_inline_cb, lf);
		else
1673 1674
			param->retval = find_line_range_by_line(sp_die, lf);
		return DWARF_CB_ABORT;
1675
	}
1676
	return DWARF_CB_OK;
1677 1678
}

1679
static int find_line_range_by_func(struct line_finder *lf)
1680
{
1681 1682 1683
	struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
	dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
	return param.retval;
1684 1685
}

1686
int 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 1691 1692
	Dwarf_Off off = 0, noff;
	size_t cuhl;
	Dwarf_Die *diep;
1693
	const char *comp_dir;
1694

1695 1696 1697 1698 1699 1700 1701 1702
	/* Fastpath: lookup by function name from .debug_pubnames section */
	if (lr->function) {
		struct pubname_callback_param pubname_param = {
			.function = lr->function, .file = lr->file,
			.cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
		struct dwarf_callback_param line_range_param = {
			.data = (void *)&lf, .retval = 0};

1703
		dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1704
				  &pubname_param, 0);
1705 1706 1707 1708 1709 1710 1711
		if (pubname_param.found) {
			line_range_search_cb(&lf.sp_die, &line_range_param);
			if (lf.found)
				goto found;
		}
	}

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 1717 1718
			break;

		/* Get the DIE(Debugging Information Entry) of this CU */
1719
		diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1720 1721
		if (!diep)
			continue;
1722 1723 1724

		/* Check if target file is included. */
		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 1733
			else {
				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

1741
found:
1742 1743 1744 1745 1746 1747 1748 1749 1750 1751
	/* Store comp_dir */
	if (lf.found) {
		comp_dir = cu_get_comp_dir(&lf.cu_die);
		if (comp_dir) {
			lr->comp_dir = strdup(comp_dir);
			if (!lr->comp_dir)
				ret = -ENOMEM;
		}
	}

1752
	pr_debug("path: %s\n", lr->path);
1753
	return (ret < 0) ? ret : lf.found;
1754 1755
}

1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813
/*
 * Find a src file from a DWARF tag path. Prepend optional source path prefix
 * and chop off leading directories that do not exist. Result is passed back as
 * a newly allocated path on success.
 * Return 0 if file was found and readable, -errno otherwise.
 */
int get_real_path(const char *raw_path, const char *comp_dir,
			 char **new_path)
{
	const char *prefix = symbol_conf.source_prefix;

	if (!prefix) {
		if (raw_path[0] != '/' && comp_dir)
			/* If not an absolute path, try to use comp_dir */
			prefix = comp_dir;
		else {
			if (access(raw_path, R_OK) == 0) {
				*new_path = strdup(raw_path);
				return *new_path ? 0 : -ENOMEM;
			} else
				return -errno;
		}
	}

	*new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
	if (!*new_path)
		return -ENOMEM;

	for (;;) {
		sprintf(*new_path, "%s/%s", prefix, raw_path);

		if (access(*new_path, R_OK) == 0)
			return 0;

		if (!symbol_conf.source_prefix) {
			/* In case of searching comp_dir, don't retry */
			zfree(new_path);
			return -errno;
		}

		switch (errno) {
		case ENAMETOOLONG:
		case ENOENT:
		case EROFS:
		case EFAULT:
			raw_path = strchr(++raw_path, '/');
			if (!raw_path) {
				zfree(new_path);
				return -ENOENT;
			}
			continue;

		default:
			zfree(new_path);
			return -errno;
		}
	}
}