probe-finder.c 34.2 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 <getopt.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <ctype.h>
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#include <dwarf-regs.h>
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#include "string.h"
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#include "event.h"
#include "debug.h"
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#include "util.h"
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#include "symbol.h"
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#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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/*
 * Compare the tail of two strings.
 * Return 0 if whole of either string is same as another's tail part.
 */
static int strtailcmp(const char *s1, const char *s2)
{
	int i1 = strlen(s1);
	int i2 = strlen(s2);
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	while (--i1 >= 0 && --i2 >= 0) {
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		if (s1[i1] != s2[i2])
			return s1[i1] - s2[i2];
	}
	return 0;
}

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/*
 * 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.
 */
static int get_real_path(const char *raw_path, char **new_path)
{
	if (!symbol_conf.source_prefix) {
		if (access(raw_path, R_OK) == 0) {
			*new_path = strdup(raw_path);
			return 0;
		} else
			return -errno;
	}

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

	for (;;) {
		sprintf(*new_path, "%s/%s", symbol_conf.source_prefix,
			raw_path);

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

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

		default:
			free(*new_path);
			*new_path = NULL;
			return -errno;
		}
	}
}

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/* Line number list operations */

/* Add a line to line number list */
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static int line_list__add_line(struct list_head *head, int line)
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{
	struct line_node *ln;
	struct list_head *p;

	/* Reverse search, because new line will be the last one */
	list_for_each_entry_reverse(ln, head, list) {
		if (ln->line < line) {
			p = &ln->list;
			goto found;
		} else if (ln->line == line)	/* Already exist */
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			return 1;
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	}
	/* List is empty, or the smallest entry */
	p = head;
found:
	pr_debug("line list: add a line %u\n", line);
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	ln = zalloc(sizeof(struct line_node));
	if (ln == NULL)
		return -ENOMEM;
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	ln->line = line;
	INIT_LIST_HEAD(&ln->list);
	list_add(&ln->list, p);
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	return 0;
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}

/* Check if the line in line number list */
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static int line_list__has_line(struct list_head *head, int line)
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{
	struct line_node *ln;

	/* Reverse search, because new line will be the last one */
	list_for_each_entry(ln, head, list)
		if (ln->line == line)
			return 1;

	return 0;
}

/* Init line number list */
static void line_list__init(struct list_head *head)
{
	INIT_LIST_HEAD(head);
}

/* Free line number list */
static void line_list__free(struct list_head *head)
{
	struct line_node *ln;
	while (!list_empty(head)) {
		ln = list_first_entry(head, struct line_node, list);
		list_del(&ln->list);
		free(ln);
	}
}

/* Dwarf wrappers */

/* Find the realpath of the target file. */
static const char *cu_find_realpath(Dwarf_Die *cu_die, const char *fname)
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{
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	Dwarf_Files *files;
	size_t nfiles, i;
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	const char *src = NULL;
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	int ret;

	if (!fname)
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		return NULL;
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	ret = dwarf_getsrcfiles(cu_die, &files, &nfiles);
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	if (ret != 0)
		return NULL;

	for (i = 0; i < nfiles; i++) {
		src = dwarf_filesrc(files, i, NULL, NULL);
		if (strtailcmp(src, fname) == 0)
			break;
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	}
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	if (i == nfiles)
		return NULL;
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	return src;
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}

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/* Compare diename and tname */
static bool die_compare_name(Dwarf_Die *dw_die, const char *tname)
{
	const char *name;
	name = dwarf_diename(dw_die);
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	return name ? strcmp(tname, name) : -1;
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}

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/* Get type die, but skip qualifiers and typedef */
static Dwarf_Die *die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
{
	Dwarf_Attribute attr;
	int tag;

	do {
		if (dwarf_attr(vr_die, DW_AT_type, &attr) == NULL ||
		    dwarf_formref_die(&attr, die_mem) == NULL)
			return NULL;

		tag = dwarf_tag(die_mem);
		vr_die = die_mem;
	} while (tag == DW_TAG_const_type ||
		 tag == DW_TAG_restrict_type ||
		 tag == DW_TAG_volatile_type ||
		 tag == DW_TAG_shared_type ||
		 tag == DW_TAG_typedef);

	return die_mem;
}

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static bool die_is_signed_type(Dwarf_Die *tp_die)
{
	Dwarf_Attribute attr;
	Dwarf_Word ret;

	if (dwarf_attr(tp_die, DW_AT_encoding, &attr) == NULL ||
	    dwarf_formudata(&attr, &ret) != 0)
		return false;

	return (ret == DW_ATE_signed_char || ret == DW_ATE_signed ||
		ret == DW_ATE_signed_fixed);
}

static int die_get_byte_size(Dwarf_Die *tp_die)
{
	Dwarf_Attribute attr;
	Dwarf_Word ret;

	if (dwarf_attr(tp_die, DW_AT_byte_size, &attr) == NULL ||
	    dwarf_formudata(&attr, &ret) != 0)
		return 0;

	return (int)ret;
}

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/* Get data_member_location offset */
static int die_get_data_member_location(Dwarf_Die *mb_die, Dwarf_Word *offs)
{
	Dwarf_Attribute attr;
	Dwarf_Op *expr;
	size_t nexpr;
	int ret;

	if (dwarf_attr(mb_die, DW_AT_data_member_location, &attr) == NULL)
		return -ENOENT;

	if (dwarf_formudata(&attr, offs) != 0) {
		/* DW_AT_data_member_location should be DW_OP_plus_uconst */
		ret = dwarf_getlocation(&attr, &expr, &nexpr);
		if (ret < 0 || nexpr == 0)
			return -ENOENT;

		if (expr[0].atom != DW_OP_plus_uconst || nexpr != 1) {
			pr_debug("Unable to get offset:Unexpected OP %x (%zd)\n",
				 expr[0].atom, nexpr);
			return -ENOTSUP;
		}
		*offs = (Dwarf_Word)expr[0].number;
	}
	return 0;
}

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/* Return values for die_find callbacks */
enum {
	DIE_FIND_CB_FOUND = 0,		/* End of Search */
	DIE_FIND_CB_CHILD = 1,		/* Search only children */
	DIE_FIND_CB_SIBLING = 2,	/* Search only siblings */
	DIE_FIND_CB_CONTINUE = 3,	/* Search children and siblings */
};

/* Search a child die */
static Dwarf_Die *die_find_child(Dwarf_Die *rt_die,
				 int (*callback)(Dwarf_Die *, void *),
				 void *data, Dwarf_Die *die_mem)
{
	Dwarf_Die child_die;
	int ret;

	ret = dwarf_child(rt_die, die_mem);
	if (ret != 0)
		return NULL;

	do {
		ret = callback(die_mem, data);
		if (ret == DIE_FIND_CB_FOUND)
			return die_mem;

		if ((ret & DIE_FIND_CB_CHILD) &&
		    die_find_child(die_mem, callback, data, &child_die)) {
			memcpy(die_mem, &child_die, sizeof(Dwarf_Die));
			return die_mem;
		}
	} while ((ret & DIE_FIND_CB_SIBLING) &&
		 dwarf_siblingof(die_mem, die_mem) == 0);

	return NULL;
}

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struct __addr_die_search_param {
	Dwarf_Addr	addr;
	Dwarf_Die	*die_mem;
};

static int __die_search_func_cb(Dwarf_Die *fn_die, void *data)
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{
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	struct __addr_die_search_param *ad = data;
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	if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
	    dwarf_haspc(fn_die, ad->addr)) {
		memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
		return DWARF_CB_ABORT;
	}
	return DWARF_CB_OK;
}
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/* Search a real subprogram including this line, */
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static Dwarf_Die *die_find_real_subprogram(Dwarf_Die *cu_die, Dwarf_Addr addr,
					   Dwarf_Die *die_mem)
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{
	struct __addr_die_search_param ad;
	ad.addr = addr;
	ad.die_mem = die_mem;
	/* dwarf_getscopes can't find subprogram. */
	if (!dwarf_getfuncs(cu_die, __die_search_func_cb, &ad, 0))
		return NULL;
	else
		return die_mem;
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}

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/* die_find callback for inline function search */
static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data)
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{
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	Dwarf_Addr *addr = data;
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	if (dwarf_tag(die_mem) == DW_TAG_inlined_subroutine &&
	    dwarf_haspc(die_mem, *addr))
		return DIE_FIND_CB_FOUND;
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	return DIE_FIND_CB_CONTINUE;
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}

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/* Similar to dwarf_getfuncs, but returns inlined_subroutine if exists. */
static Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
				      Dwarf_Die *die_mem)
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{
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	return die_find_child(sp_die, __die_find_inline_cb, &addr, die_mem);
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}

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static int __die_find_variable_cb(Dwarf_Die *die_mem, void *data)
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{
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	const char *name = data;
	int tag;
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	tag = dwarf_tag(die_mem);
	if ((tag == DW_TAG_formal_parameter ||
	     tag == DW_TAG_variable) &&
	    (die_compare_name(die_mem, name) == 0))
		return DIE_FIND_CB_FOUND;

	return DIE_FIND_CB_CONTINUE;
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}

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/* Find a variable called 'name' */
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static Dwarf_Die *die_find_variable(Dwarf_Die *sp_die, const char *name,
				    Dwarf_Die *die_mem)
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{
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	return die_find_child(sp_die, __die_find_variable_cb, (void *)name,
			      die_mem);
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}

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static int __die_find_member_cb(Dwarf_Die *die_mem, void *data)
{
	const char *name = data;

	if ((dwarf_tag(die_mem) == DW_TAG_member) &&
	    (die_compare_name(die_mem, name) == 0))
		return DIE_FIND_CB_FOUND;

	return DIE_FIND_CB_SIBLING;
}

/* Find a member called 'name' */
static Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name,
				  Dwarf_Die *die_mem)
{
	return die_find_child(st_die, __die_find_member_cb, (void *)name,
			      die_mem);
}

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/*
 * Probe finder related functions
 */

/* Show a location */
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static int convert_location(Dwarf_Op *op, struct probe_finder *pf)
411
{
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	unsigned int regn;
	Dwarf_Word offs = 0;
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	bool ref = false;
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	const char *regs;
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	struct kprobe_trace_arg *tvar = pf->tvar;
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	/* If this is based on frame buffer, set the offset */
419
	if (op->atom == DW_OP_fbreg) {
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		if (pf->fb_ops == NULL) {
			pr_warning("The attribute of frame base is not "
				   "supported.\n");
			return -ENOTSUP;
		}
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		ref = true;
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		offs = op->number;
		op = &pf->fb_ops[0];
	}
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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 {
		pr_warning("DW_OP %x is not supported.\n", op->atom);
		return -ENOTSUP;
	}
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	regs = get_arch_regstr(regn);
448
	if (!regs) {
449
		pr_warning("Mapping for DWARF register number %u missing on this architecture.", regn);
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		return -ERANGE;
	}
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	tvar->value = strdup(regs);
	if (tvar->value == NULL)
		return -ENOMEM;

457
	if (ref) {
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		tvar->ref = zalloc(sizeof(struct kprobe_trace_arg_ref));
		if (tvar->ref == NULL)
			return -ENOMEM;
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		tvar->ref->offset = (long)offs;
	}
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	return 0;
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}

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static int convert_variable_type(Dwarf_Die *vr_die,
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				 struct kprobe_trace_arg *tvar,
				 const char *cast)
469
{
470
	struct kprobe_trace_arg_ref **ref_ptr = &tvar->ref;
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	Dwarf_Die type;
	char buf[16];
	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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	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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	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: "
				   "%s(%s) is not a pointer nor array.",
				   dwarf_diename(vr_die), dwarf_diename(&type));
			return -EINVAL;
		}
		if (ret == DW_TAG_pointer_type) {
			if (die_get_real_type(&type, &type) == NULL) {
				pr_warning("Failed to get a type information.");
				return -ENOENT;
			}
			while (*ref_ptr)
				ref_ptr = &(*ref_ptr)->next;
			/* Add new reference with offset +0 */
			*ref_ptr = zalloc(sizeof(struct kprobe_trace_arg_ref));
			if (*ref_ptr == NULL) {
				pr_warning("Out of memory error\n");
				return -ENOMEM;
			}
		}
		if (die_compare_name(&type, "char") != 0 &&
		    die_compare_name(&type, "unsigned char") != 0) {
			pr_warning("Failed to cast into string: "
				   "%s is not (unsigned) char *.",
				   dwarf_diename(vr_die));
			return -EINVAL;
		}
		tvar->type = strdup(cast);
		return (tvar->type == NULL) ? -ENOMEM : 0;
	}

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	ret = die_get_byte_size(&type) * 8;
	if (ret) {
		/* Check the bitwidth */
		if (ret > MAX_BASIC_TYPE_BITS) {
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			pr_info("%s exceeds max-bitwidth."
				" Cut down to %d bits.\n",
				dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
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			ret = MAX_BASIC_TYPE_BITS;
		}

		ret = snprintf(buf, 16, "%c%d",
			       die_is_signed_type(&type) ? 's' : 'u', ret);
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		if (ret < 0 || ret >= 16) {
			if (ret >= 16)
				ret = -E2BIG;
			pr_warning("Failed to convert variable type: %s\n",
				   strerror(-ret));
			return ret;
		}
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		tvar->type = strdup(buf);
		if (tvar->type == NULL)
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			return -ENOMEM;
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	}
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	return 0;
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}

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static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
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				    struct perf_probe_arg_field *field,
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				    struct kprobe_trace_arg_ref **ref_ptr,
				    Dwarf_Die *die_mem)
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{
	struct kprobe_trace_arg_ref *ref = *ref_ptr;
	Dwarf_Die type;
	Dwarf_Word offs;
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	int ret;
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	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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	/* Check the pointer and dereference */
	if (dwarf_tag(&type) == DW_TAG_pointer_type) {
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		if (!field->ref) {
			pr_err("Semantic error: %s must be referred by '->'\n",
			       field->name);
			return -EINVAL;
		}
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		/* 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;
		}
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		/* Verify it is a data structure  */
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		if (dwarf_tag(&type) != DW_TAG_structure_type) {
			pr_warning("%s is not a data structure.\n", varname);
			return -EINVAL;
		}
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		ref = zalloc(sizeof(struct kprobe_trace_arg_ref));
		if (ref == NULL)
			return -ENOMEM;
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		if (*ref_ptr)
			(*ref_ptr)->next = ref;
		else
			*ref_ptr = ref;
	} else {
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		/* Verify it is a data structure  */
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		if (dwarf_tag(&type) != DW_TAG_structure_type) {
			pr_warning("%s is not a data structure.\n", varname);
			return -EINVAL;
		}
		if (field->ref) {
			pr_err("Semantic error: %s must be referred by '.'\n",
			       field->name);
			return -EINVAL;
		}
		if (!ref) {
			pr_warning("Structure on a register is not "
				   "supported yet.\n");
			return -ENOTSUP;
		}
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	}

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	if (die_find_member(&type, field->name, die_mem) == NULL) {
		pr_warning("%s(tyep:%s) has no member %s.\n", varname,
			   dwarf_diename(&type), field->name);
		return -EINVAL;
	}
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	/* Get the offset of the field */
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	ret = die_get_data_member_location(die_mem, &offs);
	if (ret < 0) {
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		pr_warning("Failed to get the offset of %s.\n", field->name);
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		return ret;
618
	}
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	ref->offset += (long)offs;

	/* Converting next field */
	if (field->next)
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		return convert_variable_fields(die_mem, field->name,
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					field->next, &ref, die_mem);
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	else
		return 0;
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}

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/* Show a variables in kprobe event format */
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static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
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{
	Dwarf_Attribute attr;
633
	Dwarf_Die die_mem;
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	Dwarf_Op *expr;
	size_t nexpr;
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	int ret;

638
	if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
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		goto error;
640
	/* TODO: handle more than 1 exprs */
641
	ret = dwarf_getlocation_addr(&attr, pf->addr, &expr, &nexpr, 1);
642
	if (ret <= 0 || nexpr == 0)
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		goto error;
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	ret = convert_location(expr, pf);
	if (ret == 0 && pf->pvar->field) {
		ret = convert_variable_fields(vr_die, pf->pvar->var,
					      pf->pvar->field, &pf->tvar->ref,
					      &die_mem);
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		vr_die = &die_mem;
	}
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	if (ret == 0)
		ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
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	/* *expr will be cached in libdw. Don't free it. */
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	return ret;
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error:
657
	/* TODO: Support const_value */
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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);
	return -ENOENT;
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}

/* Find a variable in a subprogram die */
664
static int find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
665
{
666
	Dwarf_Die vr_die;
667
	char buf[32], *ptr;
668
	int ret;
669

670 671
	/* TODO: Support arrays */
	if (pf->pvar->name)
672
		pf->tvar->name = strdup(pf->pvar->name);
673
	else {
674 675 676
		ret = synthesize_perf_probe_arg(pf->pvar, buf, 32);
		if (ret < 0)
			return ret;
677 678 679
		ptr = strchr(buf, ':');	/* Change type separator to _ */
		if (ptr)
			*ptr = '_';
680
		pf->tvar->name = strdup(buf);
681
	}
682 683
	if (pf->tvar->name == NULL)
		return -ENOMEM;
684 685

	if (!is_c_varname(pf->pvar->var)) {
686
		/* Copy raw parameters */
687 688 689 690 691
		pf->tvar->value = strdup(pf->pvar->var);
		if (pf->tvar->value == NULL)
			return -ENOMEM;
		else
			return 0;
692
	}
693 694 695 696 697 698 699 700 701 702

	pr_debug("Searching '%s' variable in context.\n",
		 pf->pvar->var);
	/* Search child die for local variables and parameters. */
	if (!die_find_variable(sp_die, pf->pvar->var, &vr_die)) {
		pr_warning("Failed to find '%s' in this function.\n",
			   pf->pvar->var);
		return -ENOENT;
	}
	return convert_variable(&vr_die, pf);
703 704 705
}

/* Show a probe point to output buffer */
706
static int convert_probe_point(Dwarf_Die *sp_die, struct probe_finder *pf)
707
{
708
	struct kprobe_trace_event *tev;
709 710
	Dwarf_Addr eaddr;
	Dwarf_Die die_mem;
711
	const char *name;
712
	int ret, i;
713 714
	Dwarf_Attribute fb_attr;
	size_t nops;
715

716 717 718
	if (pf->ntevs == pf->max_tevs) {
		pr_warning("Too many( > %d) probe point found.\n",
			   pf->max_tevs);
719 720
		return -ERANGE;
	}
721 722
	tev = &pf->tevs[pf->ntevs++];

723 724
	/* If no real subprogram, find a real one */
	if (!sp_die || dwarf_tag(sp_die) != DW_TAG_subprogram) {
725
		sp_die = die_find_real_subprogram(&pf->cu_die,
726
						 pf->addr, &die_mem);
727 728 729 730 731
		if (!sp_die) {
			pr_warning("Failed to find probe point in any "
				   "functions.\n");
			return -ENOENT;
		}
732 733
	}

734
	/* Copy the name of probe point */
735 736
	name = dwarf_diename(sp_die);
	if (name) {
737 738 739 740 741
		if (dwarf_entrypc(sp_die, &eaddr) != 0) {
			pr_warning("Failed to get entry pc of %s\n",
				   dwarf_diename(sp_die));
			return -ENOENT;
		}
742 743 744
		tev->point.symbol = strdup(name);
		if (tev->point.symbol == NULL)
			return -ENOMEM;
745 746
		tev->point.offset = (unsigned long)(pf->addr - eaddr);
	} else
747
		/* This function has no name. */
748 749 750 751
		tev->point.offset = (unsigned long)pf->addr;

	pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
		 tev->point.offset);
752

753 754
	/* Get the frame base attribute/ops */
	dwarf_attr(sp_die, DW_AT_frame_base, &fb_attr);
755
	ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
756
	if (ret <= 0 || nops == 0) {
757
		pf->fb_ops = NULL;
758
#if _ELFUTILS_PREREQ(0, 142)
759 760 761
	} else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
		   pf->cfi != NULL) {
		Dwarf_Frame *frame;
762 763 764 765 766 767
		if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
		    dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
			pr_warning("Failed to get CFA on 0x%jx\n",
				   (uintmax_t)pf->addr);
			return -ENOENT;
		}
768
#endif
769
	}
770

771
	/* Find each argument */
772
	tev->nargs = pf->pev->nargs;
773 774 775
	tev->args = zalloc(sizeof(struct kprobe_trace_arg) * tev->nargs);
	if (tev->args == NULL)
		return -ENOMEM;
776 777 778
	for (i = 0; i < pf->pev->nargs; i++) {
		pf->pvar = &pf->pev->args[i];
		pf->tvar = &tev->args[i];
779 780 781
		ret = find_variable(sp_die, pf);
		if (ret != 0)
			return ret;
782
	}
783 784 785

	/* *pf->fb_ops will be cached in libdw. Don't free it. */
	pf->fb_ops = NULL;
786
	return 0;
787 788 789
}

/* Find probe point from its line number */
790
static int find_probe_point_by_line(struct probe_finder *pf)
791
{
792 793 794
	Dwarf_Lines *lines;
	Dwarf_Line *line;
	size_t nlines, i;
795
	Dwarf_Addr addr;
796
	int lineno;
797
	int ret = 0;
798

799 800 801 802
	if (dwarf_getsrclines(&pf->cu_die, &lines, &nlines) != 0) {
		pr_warning("No source lines found in this CU.\n");
		return -ENOENT;
	}
803

804
	for (i = 0; i < nlines && ret == 0; i++) {
805
		line = dwarf_onesrcline(lines, i);
806 807
		if (dwarf_lineno(line, &lineno) != 0 ||
		    lineno != pf->lno)
808 809
			continue;

810 811 812
		/* TODO: Get fileno from line, but how? */
		if (strtailcmp(dwarf_linesrc(line, NULL, NULL), pf->fname) != 0)
			continue;
813

814 815 816 817
		if (dwarf_lineaddr(line, &addr) != 0) {
			pr_warning("Failed to get the address of the line.\n");
			return -ENOENT;
		}
818 819
		pr_debug("Probe line found: line[%d]:%d addr:0x%jx\n",
			 (int)i, lineno, (uintmax_t)addr);
820
		pf->addr = addr;
821

822
		ret = convert_probe_point(NULL, pf);
823 824
		/* Continuing, because target line might be inlined. */
	}
825
	return ret;
826 827
}

828 829 830 831 832
/* Find lines which match lazy pattern */
static int find_lazy_match_lines(struct list_head *head,
				 const char *fname, const char *pat)
{
	char *fbuf, *p1, *p2;
833
	int fd, line, nlines = -1;
834 835 836
	struct stat st;

	fd = open(fname, O_RDONLY);
837 838
	if (fd < 0) {
		pr_warning("Failed to open %s: %s\n", fname, strerror(-fd));
839
		return -errno;
840 841
	}

842
	if (fstat(fd, &st) < 0) {
843 844
		pr_warning("Failed to get the size of %s: %s\n",
			   fname, strerror(errno));
845 846
		nlines = -errno;
		goto out_close;
847
	}
848 849 850 851 852 853

	nlines = -ENOMEM;
	fbuf = malloc(st.st_size + 2);
	if (fbuf == NULL)
		goto out_close;
	if (read(fd, fbuf, st.st_size) < 0) {
854
		pr_warning("Failed to read %s: %s\n", fname, strerror(errno));
855 856
		nlines = -errno;
		goto out_free_fbuf;
857
	}
858 859 860 861
	fbuf[st.st_size] = '\n';	/* Dummy line */
	fbuf[st.st_size + 1] = '\0';
	p1 = fbuf;
	line = 1;
862
	nlines = 0;
863 864 865 866 867 868 869 870 871
	while ((p2 = strchr(p1, '\n')) != NULL) {
		*p2 = '\0';
		if (strlazymatch(p1, pat)) {
			line_list__add_line(head, line);
			nlines++;
		}
		line++;
		p1 = p2 + 1;
	}
872
out_free_fbuf:
873
	free(fbuf);
874 875
out_close:
	close(fd);
876 877 878 879
	return nlines;
}

/* Find probe points from lazy pattern  */
880
static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
881 882 883 884 885 886 887
{
	Dwarf_Lines *lines;
	Dwarf_Line *line;
	size_t nlines, i;
	Dwarf_Addr addr;
	Dwarf_Die die_mem;
	int lineno;
888
	int ret = 0;
889 890 891 892

	if (list_empty(&pf->lcache)) {
		/* Matching lazy line pattern */
		ret = find_lazy_match_lines(&pf->lcache, pf->fname,
893
					    pf->pev->point.lazy_line);
894 895 896 897 898
		if (ret == 0) {
			pr_debug("No matched lines found in %s.\n", pf->fname);
			return 0;
		} else if (ret < 0)
			return ret;
899 900
	}

901 902 903 904 905 906
	if (dwarf_getsrclines(&pf->cu_die, &lines, &nlines) != 0) {
		pr_warning("No source lines found in this CU.\n");
		return -ENOENT;
	}

	for (i = 0; i < nlines && ret >= 0; i++) {
907 908
		line = dwarf_onesrcline(lines, i);

909 910
		if (dwarf_lineno(line, &lineno) != 0 ||
		    !line_list__has_line(&pf->lcache, lineno))
911 912 913 914 915 916
			continue;

		/* TODO: Get fileno from line, but how? */
		if (strtailcmp(dwarf_linesrc(line, NULL, NULL), pf->fname) != 0)
			continue;

917 918 919 920 921
		if (dwarf_lineaddr(line, &addr) != 0) {
			pr_debug("Failed to get the address of line %d.\n",
				 lineno);
			continue;
		}
922 923 924 925 926
		if (sp_die) {
			/* Address filtering 1: does sp_die include addr? */
			if (!dwarf_haspc(sp_die, addr))
				continue;
			/* Address filtering 2: No child include addr? */
927
			if (die_find_inlinefunc(sp_die, addr, &die_mem))
928 929 930 931 932 933 934
				continue;
		}

		pr_debug("Probe line found: line[%d]:%d addr:0x%llx\n",
			 (int)i, lineno, (unsigned long long)addr);
		pf->addr = addr;

935
		ret = convert_probe_point(sp_die, pf);
936 937 938
		/* Continuing, because target line might be inlined. */
	}
	/* TODO: deallocate lines, but how? */
939
	return ret;
940 941
}

942 943 944 945 946 947
/* Callback parameter with return value */
struct dwarf_callback_param {
	void *data;
	int retval;
};

948 949
static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
{
950 951
	struct dwarf_callback_param *param = data;
	struct probe_finder *pf = param->data;
952
	struct perf_probe_point *pp = &pf->pev->point;
953
	Dwarf_Addr addr;
954

955
	if (pp->lazy_line)
956
		param->retval = find_probe_point_lazy(in_die, pf);
957 958
	else {
		/* Get probe address */
959 960 961 962 963 964 965
		if (dwarf_entrypc(in_die, &addr) != 0) {
			pr_warning("Failed to get entry pc of %s.\n",
				   dwarf_diename(in_die));
			param->retval = -ENOENT;
			return DWARF_CB_ABORT;
		}
		pf->addr = addr;
966 967 968 969
		pf->addr += pp->offset;
		pr_debug("found inline addr: 0x%jx\n",
			 (uintmax_t)pf->addr);

970
		param->retval = convert_probe_point(in_die, pf);
971 972
		if (param->retval < 0)
			return DWARF_CB_ABORT;
973
	}
974 975 976

	return DWARF_CB_OK;
}
977

978
/* Search function from function name */
979
static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
980
{
981 982
	struct dwarf_callback_param *param = data;
	struct probe_finder *pf = param->data;
983
	struct perf_probe_point *pp = &pf->pev->point;
984

985 986 987
	/* Check tag and diename */
	if (dwarf_tag(sp_die) != DW_TAG_subprogram ||
	    die_compare_name(sp_die, pp->function) != 0)
988
		return DWARF_CB_OK;
989

990
	pf->fname = dwarf_decl_file(sp_die);
991 992 993
	if (pp->line) { /* Function relative line */
		dwarf_decl_line(sp_die, &pf->lno);
		pf->lno += pp->line;
994
		param->retval = find_probe_point_by_line(pf);
995 996
	} else if (!dwarf_func_inline(sp_die)) {
		/* Real function */
997
		if (pp->lazy_line)
998
			param->retval = find_probe_point_lazy(sp_die, pf);
999
		else {
1000 1001 1002 1003 1004 1005
			if (dwarf_entrypc(sp_die, &pf->addr) != 0) {
				pr_warning("Failed to get entry pc of %s.\n",
					   dwarf_diename(sp_die));
				param->retval = -ENOENT;
				return DWARF_CB_ABORT;
			}
1006 1007
			pf->addr += pp->offset;
			/* TODO: Check the address in this function */
1008
			param->retval = convert_probe_point(sp_die, pf);
1009
		}
1010 1011 1012
	} else {
		struct dwarf_callback_param _param = {.data = (void *)pf,
						      .retval = 0};
1013
		/* Inlined function: search instances */
1014 1015 1016 1017
		dwarf_func_inline_instances(sp_die, probe_point_inline_cb,
					    &_param);
		param->retval = _param.retval;
	}
1018

1019
	return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1020 1021
}

1022
static int find_probe_point_by_func(struct probe_finder *pf)
1023
{
1024 1025 1026 1027
	struct dwarf_callback_param _param = {.data = (void *)pf,
					      .retval = 0};
	dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
	return _param.retval;
1028 1029
}

1030 1031
/* Find kprobe_trace_events specified by perf_probe_event from debuginfo */
int find_kprobe_trace_events(int fd, struct perf_probe_event *pev,
1032
			     struct kprobe_trace_event **tevs, int max_tevs)
1033
{
1034
	struct probe_finder pf = {.pev = pev, .max_tevs = max_tevs};
1035
	struct perf_probe_point *pp = &pev->point;
1036 1037 1038 1039
	Dwarf_Off off, noff;
	size_t cuhl;
	Dwarf_Die *diep;
	Dwarf *dbg;
1040
	int ret = 0;
1041

1042
	pf.tevs = zalloc(sizeof(struct kprobe_trace_event) * max_tevs);
1043 1044
	if (pf.tevs == NULL)
		return -ENOMEM;
1045 1046 1047
	*tevs = pf.tevs;
	pf.ntevs = 0;

1048
	dbg = dwarf_begin(fd, DWARF_C_READ);
1049 1050 1051
	if (!dbg) {
		pr_warning("No dwarf info found in the vmlinux - "
			"please rebuild with CONFIG_DEBUG_INFO=y.\n");
1052 1053
		free(pf.tevs);
		*tevs = NULL;
1054 1055
		return -EBADF;
	}
1056

1057
#if _ELFUTILS_PREREQ(0, 142)
1058 1059
	/* Get the call frame information from this dwarf */
	pf.cfi = dwarf_getcfi(dbg);
1060
#endif
1061

1062
	off = 0;
1063
	line_list__init(&pf.lcache);
1064
	/* Loop on CUs (Compilation Unit) */
1065 1066
	while (!dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL) &&
	       ret >= 0) {
1067
		/* Get the DIE(Debugging Information Entry) of this CU */
1068 1069 1070
		diep = dwarf_offdie(dbg, off + cuhl, &pf.cu_die);
		if (!diep)
			continue;
1071 1072 1073

		/* Check if target file is included. */
		if (pp->file)
1074
			pf.fname = cu_find_realpath(&pf.cu_die, pp->file);
1075
		else
1076
			pf.fname = NULL;
1077

1078
		if (!pp->file || pf.fname) {
1079
			if (pp->function)
1080
				ret = find_probe_point_by_func(&pf);
1081
			else if (pp->lazy_line)
1082
				ret = find_probe_point_lazy(NULL, &pf);
1083 1084
			else {
				pf.lno = pp->line;
1085
				ret = find_probe_point_by_line(&pf);
1086
			}
1087
		}
1088
		off = noff;
1089
	}
1090
	line_list__free(&pf.lcache);
1091
	dwarf_end(dbg);
1092

1093
	return (ret < 0) ? ret : pf.ntevs;
1094 1095
}

1096 1097 1098 1099 1100 1101 1102 1103 1104 1105
/* Reverse search */
int find_perf_probe_point(int fd, unsigned long addr,
			  struct perf_probe_point *ppt)
{
	Dwarf_Die cudie, spdie, indie;
	Dwarf *dbg;
	Dwarf_Line *line;
	Dwarf_Addr laddr, eaddr;
	const char *tmp;
	int lineno, ret = 0;
1106
	bool found = false;
1107 1108 1109

	dbg = dwarf_begin(fd, DWARF_C_READ);
	if (!dbg)
1110
		return -EBADF;
1111 1112

	/* Find cu die */
1113 1114 1115 1116
	if (!dwarf_addrdie(dbg, (Dwarf_Addr)addr, &cudie)) {
		ret = -EINVAL;
		goto end;
	}
1117 1118 1119 1120

	/* Find a corresponding line */
	line = dwarf_getsrc_die(&cudie, (Dwarf_Addr)addr);
	if (line) {
1121 1122 1123
		if (dwarf_lineaddr(line, &laddr) == 0 &&
		    (Dwarf_Addr)addr == laddr &&
		    dwarf_lineno(line, &lineno) == 0) {
1124
			tmp = dwarf_linesrc(line, NULL, NULL);
1125 1126
			if (tmp) {
				ppt->line = lineno;
1127 1128 1129 1130 1131
				ppt->file = strdup(tmp);
				if (ppt->file == NULL) {
					ret = -ENOMEM;
					goto end;
				}
1132 1133
				found = true;
			}
1134 1135 1136 1137 1138 1139
		}
	}

	/* Find a corresponding function */
	if (die_find_real_subprogram(&cudie, (Dwarf_Addr)addr, &spdie)) {
		tmp = dwarf_diename(&spdie);
1140
		if (!tmp || dwarf_entrypc(&spdie, &eaddr) != 0)
1141 1142
			goto end;

1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162
		if (ppt->line) {
			if (die_find_inlinefunc(&spdie, (Dwarf_Addr)addr,
						&indie)) {
				/* addr in an inline function */
				tmp = dwarf_diename(&indie);
				if (!tmp)
					goto end;
				ret = dwarf_decl_line(&indie, &lineno);
			} else {
				if (eaddr == addr) {	/* Function entry */
					lineno = ppt->line;
					ret = 0;
				} else
					ret = dwarf_decl_line(&spdie, &lineno);
			}
			if (ret == 0) {
				/* Make a relative line number */
				ppt->line -= lineno;
				goto found;
			}
1163
		}
1164 1165 1166
		/* We don't have a line number, let's use offset */
		ppt->offset = addr - (unsigned long)eaddr;
found:
1167 1168 1169 1170 1171
		ppt->function = strdup(tmp);
		if (ppt->function == NULL) {
			ret = -ENOMEM;
			goto end;
		}
1172
		found = true;
1173 1174 1175 1176
	}

end:
	dwarf_end(dbg);
1177 1178
	if (ret >= 0)
		ret = found ? 1 : 0;
1179 1180 1181
	return ret;
}

1182 1183 1184 1185
/* Add a line and store the src path */
static int line_range_add_line(const char *src, unsigned int lineno,
			       struct line_range *lr)
{
1186 1187
	int ret;

1188 1189
	/* Copy real path */
	if (!lr->path) {
1190 1191 1192
		ret = get_real_path(src, &lr->path);
		if (ret != 0)
			return ret;
1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213
	}
	return line_list__add_line(&lr->line_list, lineno);
}

/* Search function declaration lines */
static int line_range_funcdecl_cb(Dwarf_Die *sp_die, void *data)
{
	struct dwarf_callback_param *param = data;
	struct line_finder *lf = param->data;
	const char *src;
	int lineno;

	src = dwarf_decl_file(sp_die);
	if (src && strtailcmp(src, lf->fname) != 0)
		return DWARF_CB_OK;

	if (dwarf_decl_line(sp_die, &lineno) != 0 ||
	    (lf->lno_s > lineno || lf->lno_e < lineno))
		return DWARF_CB_OK;

	param->retval = line_range_add_line(src, lineno, lf->lr);
1214 1215
	if (param->retval < 0)
		return DWARF_CB_ABORT;
1216 1217 1218 1219 1220 1221 1222 1223 1224
	return DWARF_CB_OK;
}

static int find_line_range_func_decl_lines(struct line_finder *lf)
{
	struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
	dwarf_getfuncs(&lf->cu_die, line_range_funcdecl_cb, &param, 0);
	return param.retval;
}
1225

1226
/* Find line range from its line number */
1227
static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1228
{
1229 1230 1231
	Dwarf_Lines *lines;
	Dwarf_Line *line;
	size_t nlines, i;
1232
	Dwarf_Addr addr;
1233
	int lineno, ret = 0;
1234
	const char *src;
1235
	Dwarf_Die die_mem;
1236

1237
	line_list__init(&lf->lr->line_list);
1238 1239 1240 1241
	if (dwarf_getsrclines(&lf->cu_die, &lines, &nlines) != 0) {
		pr_warning("No source lines found in this CU.\n");
		return -ENOENT;
	}
1242

1243
	/* Search probable lines on lines list */
1244 1245
	for (i = 0; i < nlines; i++) {
		line = dwarf_onesrcline(lines, i);
1246 1247
		if (dwarf_lineno(line, &lineno) != 0 ||
		    (lf->lno_s > lineno || lf->lno_e < lineno))
1248 1249
			continue;

1250 1251
		if (sp_die) {
			/* Address filtering 1: does sp_die include addr? */
1252 1253
			if (dwarf_lineaddr(line, &addr) != 0 ||
			    !dwarf_haspc(sp_die, addr))
1254 1255 1256
				continue;

			/* Address filtering 2: No child include addr? */
1257
			if (die_find_inlinefunc(sp_die, addr, &die_mem))
1258 1259 1260
				continue;
		}

1261 1262 1263
		/* TODO: Get fileno from line, but how? */
		src = dwarf_linesrc(line, NULL, NULL);
		if (strtailcmp(src, lf->fname) != 0)
1264 1265
			continue;

1266 1267 1268
		ret = line_range_add_line(src, lineno, lf->lr);
		if (ret < 0)
			return ret;
1269
	}
1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282

	/*
	 * Dwarf lines doesn't include function declarations. We have to
	 * check functions list or given function.
	 */
	if (sp_die) {
		src = dwarf_decl_file(sp_die);
		if (src && dwarf_decl_line(sp_die, &lineno) == 0 &&
		    (lf->lno_s <= lineno && lf->lno_e >= lineno))
			ret = line_range_add_line(src, lineno, lf->lr);
	} else
		ret = find_line_range_func_decl_lines(lf);

1283
	/* Update status */
1284 1285 1286 1287 1288
	if (ret >= 0)
		if (!list_empty(&lf->lr->line_list))
			ret = lf->found = 1;
		else
			ret = 0;	/* Lines are not found */
1289 1290 1291 1292
	else {
		free(lf->lr->path);
		lf->lr->path = NULL;
	}
1293
	return ret;
1294 1295
}

1296 1297
static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
{
1298 1299 1300
	struct dwarf_callback_param *param = data;

	param->retval = find_line_range_by_line(in_die, param->data);
1301 1302 1303
	return DWARF_CB_ABORT;	/* No need to find other instances */
}

1304
/* Search function from function name */
1305
static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1306
{
1307 1308
	struct dwarf_callback_param *param = data;
	struct line_finder *lf = param->data;
1309 1310
	struct line_range *lr = lf->lr;

1311 1312 1313 1314
	if (dwarf_tag(sp_die) == DW_TAG_subprogram &&
	    die_compare_name(sp_die, lr->function) == 0) {
		lf->fname = dwarf_decl_file(sp_die);
		dwarf_decl_line(sp_die, &lr->offset);
1315
		pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1316
		lf->lno_s = lr->offset + lr->start;
1317 1318 1319 1320
		if (lf->lno_s < 0)	/* Overflow */
			lf->lno_s = INT_MAX;
		lf->lno_e = lr->offset + lr->end;
		if (lf->lno_e < 0)	/* Overflow */
1321
			lf->lno_e = INT_MAX;
1322
		pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1323 1324
		lr->start = lf->lno_s;
		lr->end = lf->lno_e;
1325 1326 1327 1328
		if (dwarf_func_inline(sp_die)) {
			struct dwarf_callback_param _param;
			_param.data = (void *)lf;
			_param.retval = 0;
1329
			dwarf_func_inline_instances(sp_die,
1330 1331 1332 1333 1334 1335
						    line_range_inline_cb,
						    &_param);
			param->retval = _param.retval;
		} else
			param->retval = find_line_range_by_line(sp_die, lf);
		return DWARF_CB_ABORT;
1336
	}
1337
	return DWARF_CB_OK;
1338 1339
}

1340
static int find_line_range_by_func(struct line_finder *lf)
1341
{
1342 1343 1344
	struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
	dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
	return param.retval;
1345 1346 1347 1348
}

int find_line_range(int fd, struct line_range *lr)
{
1349
	struct line_finder lf = {.lr = lr, .found = 0};
1350
	int ret = 0;
1351 1352 1353 1354 1355 1356
	Dwarf_Off off = 0, noff;
	size_t cuhl;
	Dwarf_Die *diep;
	Dwarf *dbg;

	dbg = dwarf_begin(fd, DWARF_C_READ);
1357 1358 1359 1360 1361
	if (!dbg) {
		pr_warning("No dwarf info found in the vmlinux - "
			"please rebuild with CONFIG_DEBUG_INFO=y.\n");
		return -EBADF;
	}
1362

1363
	/* Loop on CUs (Compilation Unit) */
1364 1365
	while (!lf.found && ret >= 0) {
		if (dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL) != 0)
1366 1367 1368
			break;

		/* Get the DIE(Debugging Information Entry) of this CU */
1369 1370 1371
		diep = dwarf_offdie(dbg, off + cuhl, &lf.cu_die);
		if (!diep)
			continue;
1372 1373 1374

		/* Check if target file is included. */
		if (lr->file)
1375
			lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1376
		else
1377
			lf.fname = 0;
1378

1379
		if (!lr->file || lf.fname) {
1380
			if (lr->function)
1381
				ret = find_line_range_by_func(&lf);
1382 1383
			else {
				lf.lno_s = lr->start;
1384
				lf.lno_e = lr->end;
1385
				ret = find_line_range_by_line(NULL, &lf);
1386 1387
			}
		}
1388
		off = noff;
1389
	}
1390 1391
	pr_debug("path: %lx\n", (unsigned long)lr->path);
	dwarf_end(dbg);
1392 1393

	return (ret < 0) ? ret : lf.found;
1394 1395
}