probe-finder.c 41.6 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 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)
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		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
}
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/*
 * Probe finder related functions
 */

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static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
154
{
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	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,
169
				     Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
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				     struct probe_trace_arg *tvar)
171
{
172
	Dwarf_Attribute attr;
173
	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;
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
	}
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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;
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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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 -ERANGE;
	}
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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;
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}

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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;
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	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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	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 */
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: "
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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)
353 354
		/* No size ... try to use default type */
		return 0;
355
	ret = BYTES_TO_BITS(ret);
356

357 358 359 360 361
	/* 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;
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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 */
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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;
447 448 449 450 451
		if (*ref_ptr)
			(*ref_ptr)->next = ref;
		else
			*ref_ptr = ref;
	} else {
452
		/* Verify it is a data structure  */
453 454 455
		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"
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Masami Hiramatsu 已提交
460
			       " nor array.\n", varname);
461 462
			return -EINVAL;
		}
463 464
		/* While prcessing unnamed field, we don't care about this */
		if (field->ref && dwarf_diename(vr_die)) {
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			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;
		}
474 475
	}

476
	if (die_find_member(&type, field->name, die_mem) == NULL) {
A
Arnaldo Carvalho de Melo 已提交
477
		pr_warning("%s(type:%s) has no member %s.\n", varname,
478 479 480
			   dwarf_diename(&type), field->name);
		return -EINVAL;
	}
481 482

	/* Get the offset of the field */
483 484 485 486 487 488 489 490 491
	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;
		}
492
	}
493 494
	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);

500
next:
501 502
	/* Converting next field */
	if (field->next)
503
		return convert_variable_fields(die_mem, field->name,
504
					field->next, &ref, die_mem);
505 506
	else
		return 0;
507 508
}

509
/* Show a variables in kprobe event format */
510
static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
511
{
512
	Dwarf_Die die_mem;
513 514
	int ret;

515 516
	pr_debug("Converting variable %s into trace event.\n",
		 dwarf_diename(vr_die));
517

518
	ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
519
					&pf->sp_die, pf->tvar);
520
	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");
525
	else if (ret == 0 && pf->pvar->field) {
526 527 528
		ret = convert_variable_fields(vr_die, pf->pvar->var,
					      pf->pvar->field, &pf->tvar->ref,
					      &die_mem);
529 530
		vr_die = &die_mem;
	}
531 532
	if (ret == 0)
		ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
533
	/* *expr will be cached in libdw. Don't free it. */
534
	return ret;
535 536
}

537 538
/* Find a variable in a scope DIE */
static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
539
{
540
	Dwarf_Die vr_die;
541
	char buf[32], *ptr;
542
	int ret = 0;
543

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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;
	}

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;
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		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. */
579 580 581
	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))
582 583
			pr_warning("Failed to find '%s' in this function.\n",
				   pf->pvar->var);
584
			ret = -ENOENT;
585
	}
586
	if (ret >= 0)
587 588
		ret = convert_variable(&vr_die, pf);

589
	return ret;
590 591
}

592
/* Convert subprogram DIE to trace point */
593 594 595
static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
				  Dwarf_Addr paddr, bool retprobe,
				  struct probe_trace_point *tp)
596
{
597
	Dwarf_Addr eaddr, highaddr;
598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617
	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;
	}

618
	symbol = dwarf_diename(sp_die);
619
	if (!symbol) {
620 621 622 623 624 625 626 627
		/* 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;
628
	}
629
	tp->offset = (unsigned long)(paddr - eaddr);
630
	tp->address = (unsigned long)paddr;
631 632 633
	tp->symbol = strdup(symbol);
	if (!tp->symbol)
		return -ENOMEM;
634

635
	/* Return probe must be on the head of a subprogram */
636 637
	if (retprobe) {
		if (eaddr != paddr) {
638
			pr_warning("Return probe must be on the head of"
M
Masami Hiramatsu 已提交
639
				   " a real function.\n");
640 641
			return -EINVAL;
		}
642
		tp->retprobe = true;
643 644
	}

645 646 647
	return 0;
}

648 649
/* Call probe_finder callback with scope DIE */
static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
650 651 652 653 654
{
	Dwarf_Attribute fb_attr;
	size_t nops;
	int ret;

655 656 657 658 659 660
	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 */
661
	if (!die_is_func_def(sc_die)) {
662
		if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
663 664 665 666
			pr_warning("Failed to find probe point in any "
				   "functions.\n");
			return -ENOENT;
		}
667 668
	} else
		memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
669

670 671
	/* Get the frame base attribute/ops from subprogram */
	dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
672
	ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
673
	if (ret <= 0 || nops == 0) {
674
		pf->fb_ops = NULL;
675
#if _ELFUTILS_PREREQ(0, 142)
676 677 678
	} else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
		   pf->cfi != NULL) {
		Dwarf_Frame *frame;
679 680
		if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
		    dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
M
Masami Hiramatsu 已提交
681
			pr_warning("Failed to get call frame on 0x%jx\n",
682 683 684
				   (uintmax_t)pf->addr);
			return -ENOENT;
		}
685
#endif
686
	}
687

688
	/* Call finder's callback handler */
689
	ret = pf->callback(sc_die, pf);
690 691 692

	/* *pf->fb_ops will be cached in libdw. Don't free it. */
	pf->fb_ops = NULL;
693 694

	return ret;
695 696
}

697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754
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;
}

755 756
static int probe_point_line_walker(const char *fname, int lineno,
				   Dwarf_Addr addr, void *data)
757
{
758
	struct probe_finder *pf = data;
759
	Dwarf_Die *sc_die, die_mem;
760
	int ret;
761

762 763
	if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
		return 0;
764

765
	pf->addr = addr;
766 767 768 769 770 771 772
	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);
773

774
	/* Continue if no error, because the line will be in inline function */
775
	return ret < 0 ? ret : 0;
776
}
777

778 779 780 781
/* 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);
782 783
}

784
/* Find lines which match lazy pattern */
785
static int find_lazy_match_lines(struct intlist *list,
786 787
				 const char *fname, const char *pat)
{
788 789 790 791 792
	FILE *fp;
	char *line = NULL;
	size_t line_len;
	ssize_t len;
	int count = 0, linenum = 1;
793
	char sbuf[STRERR_BUFSIZE];
794 795 796

	fp = fopen(fname, "r");
	if (!fp) {
797 798
		pr_warning("Failed to open %s: %s\n", fname,
			   strerror_r(errno, sbuf, sizeof(sbuf)));
799
		return -errno;
800 801
	}

802
	while ((len = getline(&line, &line_len, fp)) > 0) {
803

804 805 806 807
		if (line[len - 1] == '\n')
			line[len - 1] = '\0';

		if (strlazymatch(line, pat)) {
808
			intlist__add(list, linenum);
809
			count++;
810
		}
811
		linenum++;
812
	}
813 814 815 816 817 818 819 820 821

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

	if (count == 0)
		pr_debug("No matched lines found in %s.\n", fname);
	return count;
822 823
}

824 825 826 827
static int probe_point_lazy_walker(const char *fname, int lineno,
				   Dwarf_Addr addr, void *data)
{
	struct probe_finder *pf = data;
828
	Dwarf_Die *sc_die, die_mem;
829 830
	int ret;

831
	if (!intlist__has_entry(pf->lcache, lineno) ||
832 833 834 835 836 837
	    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;
838 839 840 841 842 843 844 845
	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);
846 847 848 849 850

	/*
	 * Continue if no error, because the lazy pattern will match
	 * to other lines
	 */
851
	return ret < 0 ? ret : 0;
852 853
}

854
/* Find probe points from lazy pattern  */
855
static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
856
{
857
	int ret = 0;
858
	char *fpath;
859

860
	if (intlist__empty(pf->lcache)) {
861 862 863 864 865 866 867 868 869
		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;
		}

870
		/* Matching lazy line pattern */
871
		ret = find_lazy_match_lines(pf->lcache, fpath,
872
					    pf->pev->point.lazy_line);
873
		free(fpath);
874
		if (ret <= 0)
875
			return ret;
876 877
	}

878
	return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
879 880
}

881 882
static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
{
883
	struct probe_finder *pf = data;
884
	struct perf_probe_point *pp = &pf->pev->point;
885
	Dwarf_Addr addr;
886
	int ret;
887

888
	if (pp->lazy_line)
889
		ret = find_probe_point_lazy(in_die, pf);
890 891
	else {
		/* Get probe address */
892
		if (dwarf_entrypc(in_die, &addr) != 0) {
M
Masami Hiramatsu 已提交
893
			pr_warning("Failed to get entry address of %s.\n",
894
				   dwarf_diename(in_die));
895
			return -ENOENT;
896 897
		}
		pf->addr = addr;
898 899 900 901
		pf->addr += pp->offset;
		pr_debug("found inline addr: 0x%jx\n",
			 (uintmax_t)pf->addr);

902
		ret = call_probe_finder(in_die, pf);
903
	}
904

905
	return ret;
906
}
907

908 909 910 911 912 913
/* Callback parameter with return value for libdw */
struct dwarf_callback_param {
	void *data;
	int retval;
};

914
/* Search function from function name */
915
static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
916
{
917 918
	struct dwarf_callback_param *param = data;
	struct probe_finder *pf = param->data;
919
	struct perf_probe_point *pp = &pf->pev->point;
920

921
	/* Check tag and diename */
922 923
	if (!die_is_func_def(sp_die) ||
	    !die_compare_name(sp_die, pp->function))
924
		return DWARF_CB_OK;
925

926 927 928 929
	/* Check declared file */
	if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
		return DWARF_CB_OK;

930
	pf->fname = dwarf_decl_file(sp_die);
931 932 933
	if (pp->line) { /* Function relative line */
		dwarf_decl_line(sp_die, &pf->lno);
		pf->lno += pp->line;
934
		param->retval = find_probe_point_by_line(pf);
935 936 937
	} else if (die_is_func_instance(sp_die)) {
		/* Instances always have the entry address */
		dwarf_entrypc(sp_die, &pf->addr);
938
		/* Real function */
939
		if (pp->lazy_line)
940
			param->retval = find_probe_point_lazy(sp_die, pf);
941 942 943
		else {
			pf->addr += pp->offset;
			/* TODO: Check the address in this function */
944
			param->retval = call_probe_finder(sp_die, pf);
945
		}
946
	} else
947
		/* Inlined function: search instances */
948 949
		param->retval = die_walk_instances(sp_die,
					probe_point_inline_cb, (void *)pf);
950

951
	return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
952 953
}

954
static int find_probe_point_by_func(struct probe_finder *pf)
955
{
956 957 958 959
	struct dwarf_callback_param _param = {.data = (void *)pf,
					      .retval = 0};
	dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
	return _param.retval;
960 961
}

962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993
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;

		if (die_compare_name(param->sp_die, param->function)) {
			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;
}

994
/* Find probe points from debuginfo */
995
static int debuginfo__find_probes(struct debuginfo *dbg,
996
				  struct probe_finder *pf)
997
{
998
	struct perf_probe_point *pp = &pf->pev->point;
999 1000 1001
	Dwarf_Off off, noff;
	size_t cuhl;
	Dwarf_Die *diep;
1002
	int ret = 0;
1003

1004
#if _ELFUTILS_PREREQ(0, 142)
1005 1006 1007 1008
	Elf *elf;
	GElf_Ehdr ehdr;
	GElf_Shdr shdr;

1009
	/* Get the call frame information from this dwarf */
1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022
	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 = dwarf_getcfi_elf(elf);
	} else {
		pf->cfi = dwarf_getcfi(dbg->dbg);
	}
1023
#endif
1024

1025
	off = 0;
1026 1027 1028
	pf->lcache = intlist__new(NULL);
	if (!pf->lcache)
		return -ENOMEM;
1029 1030 1031 1032 1033 1034 1035 1036

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

1043
		dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1044
				  &pubname_param, 0);
1045 1046 1047 1048 1049 1050 1051
		if (pubname_param.found) {
			ret = probe_point_search_cb(&pf->sp_die, &probe_param);
			if (ret)
				goto found;
		}
	}

1052
	/* Loop on CUs (Compilation Unit) */
1053
	while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1054
		/* Get the DIE(Debugging Information Entry) of this CU */
1055
		diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1056 1057
		if (!diep)
			continue;
1058 1059 1060

		/* Check if target file is included. */
		if (pp->file)
1061
			pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1062
		else
1063
			pf->fname = NULL;
1064

1065
		if (!pp->file || pf->fname) {
1066
			if (pp->function)
1067
				ret = find_probe_point_by_func(pf);
1068
			else if (pp->lazy_line)
1069
				ret = find_probe_point_lazy(&pf->cu_die, pf);
1070
			else {
1071 1072
				pf->lno = pp->line;
				ret = find_probe_point_by_line(pf);
1073
			}
1074
			if (ret < 0)
1075
				break;
1076
		}
1077
		off = noff;
1078
	}
1079 1080

found:
1081 1082
	intlist__delete(pf->lcache);
	pf->lcache = NULL;
1083

1084 1085 1086
	return ret;
}

1087 1088 1089
struct local_vars_finder {
	struct probe_finder *pf;
	struct perf_probe_arg *args;
1090
	bool vars;
1091 1092 1093 1094 1095 1096 1097 1098 1099
	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;
1100
	struct probe_finder *pf = vf->pf;
1101 1102 1103 1104
	int tag;

	tag = dwarf_tag(die_mem);
	if (tag == DW_TAG_formal_parameter ||
1105
	    (tag == DW_TAG_variable && vf->vars)) {
1106
		if (convert_variable_location(die_mem, vf->pf->addr,
1107 1108
					      vf->pf->fb_ops, &pf->sp_die,
					      NULL) == 0) {
1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130
			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;
1131
	struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1132 1133 1134 1135
				.max_args = MAX_PROBE_ARGS, .ret = 0};

	for (i = 0; i < pf->pev->nargs; i++) {
		/* var never be NULL */
1136 1137 1138
		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) {
1139 1140 1141
			/* Copy normal argument */
			args[n] = pf->pev->args[i];
			n++;
1142
			continue;
1143
		}
1144 1145 1146 1147 1148 1149 1150 1151 1152
		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;
1153 1154 1155 1156
	}
	return n;
}

1157
/* Add a found probe point into trace event list */
1158
static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1159 1160 1161 1162
{
	struct trace_event_finder *tf =
			container_of(pf, struct trace_event_finder, pf);
	struct probe_trace_event *tev;
1163
	struct perf_probe_arg *args;
1164 1165 1166 1167 1168 1169 1170 1171 1172 1173
	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++];

1174
	/* Trace point should be converted from subprogram DIE */
1175
	ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1176
				     pf->pev->point.retprobe, &tev->point);
1177 1178 1179 1180 1181 1182
	if (ret < 0)
		return ret;

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

1183 1184 1185
	/* Expand special probe argument if exist */
	args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
	if (args == NULL)
1186
		return -ENOMEM;
1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201

	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];
1202
		pf->tvar = &tev->args[i];
1203 1204
		/* Variable should be found from scope DIE */
		ret = find_variable(sc_die, pf);
1205
		if (ret != 0)
1206
			break;
1207 1208
	}

1209 1210 1211
end:
	free(args);
	return ret;
1212 1213 1214
}

/* Find probe_trace_events specified by perf_probe_event from debuginfo */
1215
int debuginfo__find_trace_events(struct debuginfo *dbg,
1216
				 struct perf_probe_event *pev,
1217
				 struct probe_trace_event **tevs)
1218 1219 1220
{
	struct trace_event_finder tf = {
			.pf = {.pev = pev, .callback = add_probe_trace_event},
1221
			.max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1222 1223 1224
	int ret;

	/* Allocate result tevs array */
1225
	*tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1226 1227 1228 1229 1230 1231
	if (*tevs == NULL)
		return -ENOMEM;

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

1232
	ret = debuginfo__find_probes(dbg, &tf.pf);
1233
	if (ret < 0) {
1234
		zfree(tevs);
1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256
		return ret;
	}

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

#define MAX_VAR_LEN 64

/* 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;
	char buf[MAX_VAR_LEN];
	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,
1257 1258
						af->pf.fb_ops, &af->pf.sp_die,
						NULL);
1259 1260
		if (ret == 0) {
			ret = die_get_varname(die_mem, buf, MAX_VAR_LEN);
1261
			pr_debug2("Add new var: %s\n", buf);
1262 1263 1264 1265 1266
			if (ret > 0)
				strlist__add(vl->vars, buf);
		}
	}

1267
	if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1268 1269 1270 1271 1272 1273
		return DIE_FIND_CB_CONTINUE;
	else
		return DIE_FIND_CB_SIBLING;
}

/* Add a found vars into available variables list */
1274
static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1275 1276 1277 1278
{
	struct available_var_finder *af =
			container_of(pf, struct available_var_finder, pf);
	struct variable_list *vl;
1279 1280
	Dwarf_Die die_mem;
	int ret;
1281 1282 1283 1284 1285 1286 1287 1288

	/* 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++];

1289
	/* Trace point should be converted from subprogram DIE */
1290
	ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1291
				     pf->pev->point.retprobe, &vl->point);
1292 1293 1294 1295 1296 1297 1298 1299 1300 1301
	if (ret < 0)
		return ret;

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

	/* Find local variables */
	vl->vars = strlist__new(true, NULL);
	if (vl->vars == NULL)
		return -ENOMEM;
1302
	af->child = true;
1303
	die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1304

1305
	/* Find external variables */
1306
	if (!probe_conf.show_ext_vars)
1307
		goto out;
1308
	/* Don't need to search child DIE for external vars. */
1309
	af->child = false;
1310
	die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1311 1312

out:
1313 1314 1315 1316 1317 1318 1319 1320
	if (strlist__empty(vl->vars)) {
		strlist__delete(vl->vars);
		vl->vars = NULL;
	}

	return ret;
}

1321 1322 1323 1324 1325
/*
 * 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.
 */
1326
int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1327
				      struct perf_probe_event *pev,
1328
				      struct variable_list **vls)
1329 1330 1331
{
	struct available_var_finder af = {
			.pf = {.pev = pev, .callback = add_available_vars},
1332
			.mod = dbg->mod,
1333
			.max_vls = probe_conf.max_probes};
1334 1335 1336
	int ret;

	/* Allocate result vls array */
1337
	*vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1338 1339 1340 1341 1342 1343
	if (*vls == NULL)
		return -ENOMEM;

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

1344
	ret = debuginfo__find_probes(dbg, &af.pf);
1345 1346 1347
	if (ret < 0) {
		/* Free vlist for error */
		while (af.nvls--) {
1348
			zfree(&af.vls[af.nvls].point.symbol);
1349
			strlist__delete(af.vls[af.nvls].vars);
1350
		}
1351
		zfree(vls);
1352 1353 1354 1355
		return ret;
	}

	return (ret < 0) ? ret : af.nvls;
1356 1357
}

1358
/* Reverse search */
1359
int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1360
				struct perf_probe_point *ppt)
1361 1362
{
	Dwarf_Die cudie, spdie, indie;
1363 1364
	Dwarf_Addr _addr = 0, baseaddr = 0;
	const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1365
	int baseline = 0, lineno = 0, ret = 0;
1366 1367

	/* Find cu die */
1368
	if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
M
Masami Hiramatsu 已提交
1369 1370
		pr_warning("Failed to find debug information for address %lx\n",
			   addr);
1371 1372 1373
		ret = -EINVAL;
		goto end;
	}
1374

1375 1376 1377
	/* Find a corresponding line (filename and lineno) */
	cu_find_lineinfo(&cudie, addr, &fname, &lineno);
	/* Don't care whether it failed or not */
1378

1379
	/* Find a corresponding function (name, baseline and baseaddr) */
1380
	if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1381
		/* Get function entry information */
1382 1383
		func = basefunc = dwarf_diename(&spdie);
		if (!func ||
1384
		    dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1385 1386
		    dwarf_decl_line(&spdie, &baseline) != 0) {
			lineno = 0;
1387
			goto post;
1388
		}
1389

1390
		fname = dwarf_decl_file(&spdie);
1391
		if (addr == (unsigned long)baseaddr) {
1392 1393
			/* Function entry - Relative line number is 0 */
			lineno = baseline;
1394 1395 1396 1397 1398 1399 1400
			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 */
1401
			if (dwarf_entrypc(&indie, &_addr) == 0 &&
1402
			    _addr == addr) {
1403 1404 1405
				/*
				 * addr is at an inline function entry.
				 * In this case, lineno should be the call-site
1406
				 * line number. (overwrite lineinfo)
1407 1408
				 */
				lineno = die_get_call_lineno(&indie);
1409 1410 1411
				fname = die_get_call_file(&indie);
				break;
			} else {
1412 1413 1414 1415 1416 1417
				/*
				 * 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.
				 */
1418
				tmp = dwarf_diename(&indie);
1419 1420 1421 1422 1423
				if (!tmp ||
				    dwarf_decl_line(&indie, &baseline) != 0)
					break;
				func = tmp;
				spdie = indie;
1424
			}
1425
		}
1426 1427 1428 1429
		/* Verify the lineno and baseline are in a same file */
		tmp = dwarf_decl_file(&spdie);
		if (!tmp || strcmp(tmp, fname) != 0)
			lineno = 0;
1430 1431 1432 1433 1434 1435
	}

post:
	/* Make a relative line number or an offset */
	if (lineno)
		ppt->line = lineno - baseline;
1436
	else if (basefunc) {
1437
		ppt->offset = addr - (unsigned long)baseaddr;
1438 1439
		func = basefunc;
	}
1440 1441 1442 1443

	/* Duplicate strings */
	if (func) {
		ppt->function = strdup(func);
1444 1445 1446 1447
		if (ppt->function == NULL) {
			ret = -ENOMEM;
			goto end;
		}
1448
	}
1449 1450 1451
	if (fname) {
		ppt->file = strdup(fname);
		if (ppt->file == NULL) {
1452
			zfree(&ppt->function);
1453 1454 1455 1456
			ret = -ENOMEM;
			goto end;
		}
	}
1457
end:
1458 1459
	if (ret == 0 && (fname || func))
		ret = 1;	/* Found a point */
1460 1461 1462
	return ret;
}

1463 1464 1465 1466
/* Add a line and store the src path */
static int line_range_add_line(const char *src, unsigned int lineno,
			       struct line_range *lr)
{
1467
	/* Copy source path */
1468
	if (!lr->path) {
1469 1470 1471
		lr->path = strdup(src);
		if (lr->path == NULL)
			return -ENOMEM;
1472
	}
1473
	return intlist__add(lr->line_list, lineno);
1474 1475
}

1476
static int line_range_walk_cb(const char *fname, int lineno,
1477
			      Dwarf_Addr addr __maybe_unused,
1478
			      void *data)
1479
{
1480
	struct line_finder *lf = data;
1481
	int err;
1482

1483
	if ((strtailcmp(fname, lf->fname) != 0) ||
1484
	    (lf->lno_s > lineno || lf->lno_e < lineno))
1485
		return 0;
1486

1487 1488 1489
	err = line_range_add_line(fname, lineno, lf->lr);
	if (err < 0 && err != -EEXIST)
		return err;
1490

1491
	return 0;
1492
}
1493

1494
/* Find line range from its line number */
1495
static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1496
{
1497
	int ret;
1498

1499
	ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1500

1501
	/* Update status */
1502
	if (ret >= 0)
1503
		if (!intlist__empty(lf->lr->line_list))
1504 1505 1506
			ret = lf->found = 1;
		else
			ret = 0;	/* Lines are not found */
1507
	else {
1508
		zfree(&lf->lr->path);
1509
	}
1510
	return ret;
1511 1512
}

1513 1514
static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
{
1515
	int ret = find_line_range_by_line(in_die, data);
1516 1517 1518 1519

	/*
	 * We have to check all instances of inlined function, because
	 * some execution paths can be optimized out depends on the
1520 1521
	 * function argument of instances. However, if an error occurs,
	 * it should be handled by the caller.
1522
	 */
1523
	return ret < 0 ? ret : 0;
1524 1525
}

1526
/* Search function definition from function name */
1527
static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1528
{
1529 1530
	struct dwarf_callback_param *param = data;
	struct line_finder *lf = param->data;
1531 1532
	struct line_range *lr = lf->lr;

1533 1534 1535 1536
	/* Check declared file */
	if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
		return DWARF_CB_OK;

1537
	if (die_is_func_def(sp_die) &&
1538
	    die_compare_name(sp_die, lr->function)) {
1539 1540
		lf->fname = dwarf_decl_file(sp_die);
		dwarf_decl_line(sp_die, &lr->offset);
1541
		pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1542
		lf->lno_s = lr->offset + lr->start;
1543 1544 1545 1546
		if (lf->lno_s < 0)	/* Overflow */
			lf->lno_s = INT_MAX;
		lf->lno_e = lr->offset + lr->end;
		if (lf->lno_e < 0)	/* Overflow */
1547
			lf->lno_e = INT_MAX;
1548
		pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1549 1550
		lr->start = lf->lno_s;
		lr->end = lf->lno_e;
1551
		if (!die_is_func_instance(sp_die))
1552 1553 1554
			param->retval = die_walk_instances(sp_die,
						line_range_inline_cb, lf);
		else
1555 1556
			param->retval = find_line_range_by_line(sp_die, lf);
		return DWARF_CB_ABORT;
1557
	}
1558
	return DWARF_CB_OK;
1559 1560
}

1561
static int find_line_range_by_func(struct line_finder *lf)
1562
{
1563 1564 1565
	struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
	dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
	return param.retval;
1566 1567
}

1568
int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1569
{
1570
	struct line_finder lf = {.lr = lr, .found = 0};
1571
	int ret = 0;
1572 1573 1574
	Dwarf_Off off = 0, noff;
	size_t cuhl;
	Dwarf_Die *diep;
1575
	const char *comp_dir;
1576

1577 1578 1579 1580 1581 1582 1583 1584
	/* 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};

1585
		dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1586
				  &pubname_param, 0);
1587 1588 1589 1590 1591 1592 1593
		if (pubname_param.found) {
			line_range_search_cb(&lf.sp_die, &line_range_param);
			if (lf.found)
				goto found;
		}
	}

1594
	/* Loop on CUs (Compilation Unit) */
1595
	while (!lf.found && ret >= 0) {
1596
		if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1597
				 NULL, NULL, NULL) != 0)
1598 1599 1600
			break;

		/* Get the DIE(Debugging Information Entry) of this CU */
1601
		diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1602 1603
		if (!diep)
			continue;
1604 1605 1606

		/* Check if target file is included. */
		if (lr->file)
1607
			lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1608
		else
1609
			lf.fname = 0;
1610

1611
		if (!lr->file || lf.fname) {
1612
			if (lr->function)
1613
				ret = find_line_range_by_func(&lf);
1614 1615
			else {
				lf.lno_s = lr->start;
1616
				lf.lno_e = lr->end;
1617
				ret = find_line_range_by_line(NULL, &lf);
1618 1619
			}
		}
1620
		off = noff;
1621
	}
1622

1623
found:
1624 1625 1626 1627 1628 1629 1630 1631 1632 1633
	/* 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;
		}
	}

1634
	pr_debug("path: %s\n", lr->path);
1635
	return (ret < 0) ? ret : lf.found;
1636 1637
}

1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695
/*
 * 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;
		}
	}
}