probe-finder.c 47.3 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 <linux/bitops.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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/* 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);
	}
}

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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 */
static Dwarf *dwfl_init_offline_dwarf(int fd, Dwfl **dwflp, Dwarf_Addr *bias)
{
	Dwfl_Module *mod;
	Dwarf *dbg = NULL;

	if (!dwflp)
		return NULL;

	*dwflp = dwfl_begin(&offline_callbacks);
	if (!*dwflp)
		return NULL;

	mod = dwfl_report_offline(*dwflp, "", "", fd);
	if (!mod)
		goto error;

	dbg = dwfl_module_getdwarf(mod, bias);
	if (!dbg) {
error:
		dwfl_end(*dwflp);
		*dwflp = NULL;
	}
	return dbg;
}

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#if _ELFUTILS_PREREQ(0, 148)
/* This method is buggy if elfutils is older than 0.148 */
static int __linux_kernel_find_elf(Dwfl_Module *mod,
				   void **userdata,
				   const char *module_name,
				   Dwarf_Addr base,
				   char **file_name, Elf **elfp)
{
	int fd;
	const char *path = kernel_get_module_path(module_name);

	pr_debug2("Use file %s for %s\n", path, module_name);
	if (path) {
		fd = open(path, O_RDONLY);
		if (fd >= 0) {
			*file_name = strdup(path);
			return fd;
		}
	}
	/* If failed, try to call standard method */
	return dwfl_linux_kernel_find_elf(mod, userdata, module_name, base,
					  file_name, elfp);
}

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

	.find_elf = __linux_kernel_find_elf,
	.section_address = dwfl_linux_kernel_module_section_address,
};

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/* Get a Dwarf from live kernel image */
static Dwarf *dwfl_init_live_kernel_dwarf(Dwarf_Addr addr, Dwfl **dwflp,
					  Dwarf_Addr *bias)
{
	Dwarf *dbg;

	if (!dwflp)
		return NULL;

	*dwflp = dwfl_begin(&kernel_callbacks);
	if (!*dwflp)
		return NULL;

	/* Load the kernel dwarves: Don't care the result here */
	dwfl_linux_kernel_report_kernel(*dwflp);
	dwfl_linux_kernel_report_modules(*dwflp);

	dbg = dwfl_addrdwarf(*dwflp, addr, bias);
	/* Here, check whether we could get a real dwarf */
	if (!dbg) {
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		pr_debug("Failed to find kernel dwarf at %lx\n",
			 (unsigned long)addr);
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		dwfl_end(*dwflp);
		*dwflp = NULL;
	}
	return dbg;
}
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#else
/* With older elfutils, this just support kernel module... */
static Dwarf *dwfl_init_live_kernel_dwarf(Dwarf_Addr addr __used, Dwfl **dwflp,
					  Dwarf_Addr *bias)
{
	int fd;
	const char *path = kernel_get_module_path("kernel");

	if (!path) {
		pr_err("Failed to find vmlinux path\n");
		return NULL;
	}

	pr_debug2("Use file %s for debuginfo\n", path);
	fd = open(path, O_RDONLY);
	if (fd < 0)
		return NULL;

	return dwfl_init_offline_dwarf(fd, dwflp, bias);
}
#endif
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/* 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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/* Get DW_AT_comp_dir (should be NULL with older gcc) */
static const char *cu_get_comp_dir(Dwarf_Die *cu_die)
{
	Dwarf_Attribute attr;
	if (dwarf_attr(cu_die, DW_AT_comp_dir, &attr) == NULL)
		return NULL;
	return dwarf_formstring(&attr);
}

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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) == 0) : false;
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}

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/* Get callsite line number of inline-function instance */
static int die_get_call_lineno(Dwarf_Die *in_die)
{
	Dwarf_Attribute attr;
	Dwarf_Word ret;

	if (!dwarf_attr(in_die, DW_AT_call_line, &attr))
		return -ENOENT;

	dwarf_formudata(&attr, &ret);
	return (int)ret;
}

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/* Get type die */
static Dwarf_Die *die_get_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
{
	Dwarf_Attribute attr;

	if (dwarf_attr_integrate(vr_die, DW_AT_type, &attr) &&
	    dwarf_formref_die(&attr, die_mem))
		return die_mem;
	else
		return NULL;
}

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/* Get a type die, but skip qualifiers */
static Dwarf_Die *__die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
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{
	int tag;

	do {
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		vr_die = die_get_type(vr_die, die_mem);
		if (!vr_die)
			break;
		tag = dwarf_tag(vr_die);
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	} while (tag == DW_TAG_const_type ||
		 tag == DW_TAG_restrict_type ||
		 tag == DW_TAG_volatile_type ||
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		 tag == DW_TAG_shared_type);

	return vr_die;
}

/* Get a type die, but skip qualifiers and typedef */
static Dwarf_Die *die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
{
	do {
		vr_die = __die_get_real_type(vr_die, die_mem);
	} while (vr_die && dwarf_tag(vr_die) == DW_TAG_typedef);
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	return vr_die;
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}

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static int die_get_attr_udata(Dwarf_Die *tp_die, unsigned int attr_name,
			      Dwarf_Word *result)
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{
	Dwarf_Attribute attr;
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	if (dwarf_attr(tp_die, attr_name, &attr) == NULL ||
	    dwarf_formudata(&attr, result) != 0)
		return -ENOENT;

	return 0;
}

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

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	if (die_get_attr_udata(tp_die, DW_AT_encoding, &ret))
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		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_Word ret;

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	if (die_get_attr_udata(tp_die, DW_AT_byte_size, &ret))
		return 0;

	return (int)ret;
}

static int die_get_bit_size(Dwarf_Die *tp_die)
{
	Dwarf_Word ret;

	if (die_get_attr_udata(tp_die, DW_AT_bit_size, &ret))
		return 0;

	return (int)ret;
}

static int die_get_bit_offset(Dwarf_Die *tp_die)
{
	Dwarf_Word ret;

	if (die_get_attr_udata(tp_die, DW_AT_bit_offset, &ret))
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		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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/* Walker on lines (Note: line number will not be sorted) */
typedef int (* line_walk_handler_t) (const char *fname, int lineno,
				     Dwarf_Addr addr, void *data);

struct __line_walk_param {
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	const char *fname;
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	line_walk_handler_t handler;
	void *data;
	int retval;
};

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static int __die_walk_funclines_cb(Dwarf_Die *in_die, void *data)
{
	struct __line_walk_param *lw = data;
	Dwarf_Addr addr;
	int lineno;

	if (dwarf_tag(in_die) == DW_TAG_inlined_subroutine) {
		lineno = die_get_call_lineno(in_die);
		if (lineno > 0 && dwarf_entrypc(in_die, &addr) == 0) {
			lw->retval = lw->handler(lw->fname, lineno, addr,
						 lw->data);
			if (lw->retval != 0)
				return DIE_FIND_CB_FOUND;
		}
	}
	return DIE_FIND_CB_SIBLING;
}

/* Walk on lines of blocks included in given DIE */
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static int __die_walk_funclines(Dwarf_Die *sp_die,
				line_walk_handler_t handler, void *data)
{
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	struct __line_walk_param lw = {
		.handler = handler,
		.data = data,
		.retval = 0,
	};
	Dwarf_Die die_mem;
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	Dwarf_Addr addr;
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	int lineno;
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	/* Handle function declaration line */
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	lw.fname = dwarf_decl_file(sp_die);
	if (lw.fname && dwarf_decl_line(sp_die, &lineno) == 0 &&
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	    dwarf_entrypc(sp_die, &addr) == 0) {
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		lw.retval = handler(lw.fname, lineno, addr, data);
		if (lw.retval != 0)
			goto done;
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	}
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	die_find_child(sp_die, __die_walk_funclines_cb, &lw, &die_mem);
done:
	return lw.retval;
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}

static int __die_walk_culines_cb(Dwarf_Die *sp_die, void *data)
{
	struct __line_walk_param *lw = data;

	lw->retval = __die_walk_funclines(sp_die, lw->handler, lw->data);
	if (lw->retval != 0)
		return DWARF_CB_ABORT;

	return DWARF_CB_OK;
}

/*
 * Walk on lines inside given PDIE. If the PDIE is subprogram, walk only on
 * the lines inside the subprogram, otherwise PDIE must be a CU DIE.
 */
static int die_walk_lines(Dwarf_Die *pdie, line_walk_handler_t handler,
			  void *data)
{
	Dwarf_Lines *lines;
	Dwarf_Line *line;
	Dwarf_Addr addr;
	const char *fname;
	int lineno, ret = 0;
	Dwarf_Die die_mem, *cu_die;
	size_t nlines, i;

	/* Get the CU die */
	if (dwarf_tag(pdie) == DW_TAG_subprogram)
		cu_die = dwarf_diecu(pdie, &die_mem, NULL, NULL);
	else
		cu_die = pdie;
	if (!cu_die) {
		pr_debug2("Failed to get CU from subprogram\n");
		return -EINVAL;
	}

	/* Get lines list in the CU */
	if (dwarf_getsrclines(cu_die, &lines, &nlines) != 0) {
		pr_debug2("Failed to get source lines on this CU.\n");
		return -ENOENT;
	}
	pr_debug2("Get %zd lines from this CU\n", nlines);

	/* Walk on the lines on lines list */
	for (i = 0; i < nlines; i++) {
		line = dwarf_onesrcline(lines, i);
		if (line == NULL ||
		    dwarf_lineno(line, &lineno) != 0 ||
		    dwarf_lineaddr(line, &addr) != 0) {
			pr_debug2("Failed to get line info. "
				  "Possible error in debuginfo.\n");
			continue;
		}
		/* Filter lines based on address */
		if (pdie != cu_die)
			/*
			 * Address filtering
			 * The line is included in given function, and
			 * no inline block includes it.
			 */
			if (!dwarf_haspc(pdie, addr) ||
			    die_find_inlinefunc(pdie, addr, &die_mem))
				continue;
		/* Get source line */
		fname = dwarf_linesrc(line, NULL, NULL);

		ret = handler(fname, lineno, addr, data);
		if (ret != 0)
			return ret;
	}

	/*
	 * Dwarf lines doesn't include function declarations and inlined
	 * subroutines. We have to check functions list or given function.
	 */
	if (pdie != cu_die)
		ret = __die_walk_funclines(pdie, handler, data);
	else {
		struct __line_walk_param param = {
			.handler = handler,
			.data = data,
			.retval = 0,
		};
		dwarf_getfuncs(cu_die, __die_walk_culines_cb, &param, 0);
		ret = param.retval;
	}

	return ret;
}

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struct __find_variable_param {
	const char *name;
	Dwarf_Addr addr;
};

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static int __die_find_variable_cb(Dwarf_Die *die_mem, void *data)
654
{
655
	struct __find_variable_param *fvp = data;
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	int tag;
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	tag = dwarf_tag(die_mem);
	if ((tag == DW_TAG_formal_parameter ||
	     tag == DW_TAG_variable) &&
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	    die_compare_name(die_mem, fvp->name))
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		return DIE_FIND_CB_FOUND;

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

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/* Find a variable called 'name' at given address */
static Dwarf_Die *die_find_variable_at(Dwarf_Die *sp_die, const char *name,
				       Dwarf_Addr addr, Dwarf_Die *die_mem)
673
{
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	struct __find_variable_param fvp = { .name = name, .addr = addr};

	return die_find_child(sp_die, __die_find_variable_cb, (void *)&fvp,
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			      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) &&
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	    die_compare_name(die_mem, name))
686 687 688 689 690 691 692 693 694 695 696 697 698
		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);
}

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
/* Get the name of given variable DIE */
static int die_get_typename(Dwarf_Die *vr_die, char *buf, int len)
{
	Dwarf_Die type;
	int tag, ret, ret2;
	const char *tmp = "";

	if (__die_get_real_type(vr_die, &type) == NULL)
		return -ENOENT;

	tag = dwarf_tag(&type);
	if (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)
		tmp = "*";
	else if (tag == DW_TAG_subroutine_type) {
		/* Function pointer */
		ret = snprintf(buf, len, "(function_type)");
		return (ret >= len) ? -E2BIG : ret;
	} else {
		if (!dwarf_diename(&type))
			return -ENOENT;
		if (tag == DW_TAG_union_type)
			tmp = "union ";
		else if (tag == DW_TAG_structure_type)
			tmp = "struct ";
		/* Write a base name */
		ret = snprintf(buf, len, "%s%s", tmp, dwarf_diename(&type));
		return (ret >= len) ? -E2BIG : ret;
	}
	ret = die_get_typename(&type, buf, len);
	if (ret > 0) {
		ret2 = snprintf(buf + ret, len - ret, "%s", tmp);
		ret = (ret2 >= len - ret) ? -E2BIG : ret2 + ret;
	}
	return ret;
}

/* Get the name and type of given variable DIE, stored as "type\tname" */
static int die_get_varname(Dwarf_Die *vr_die, char *buf, int len)
{
	int ret, ret2;

	ret = die_get_typename(vr_die, buf, len);
	if (ret < 0) {
		pr_debug("Failed to get type, make it unknown.\n");
		ret = snprintf(buf, len, "(unknown_type)");
	}
	if (ret > 0) {
		ret2 = snprintf(buf + ret, len - ret, "\t%s",
				dwarf_diename(vr_die));
		ret = (ret2 >= len - ret) ? -E2BIG : ret2 + ret;
	}
	return ret;
}

753 754 755 756
/*
 * Probe finder related functions
 */

757
static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
758
{
759 760
	struct probe_trace_arg_ref *ref;
	ref = zalloc(sizeof(struct probe_trace_arg_ref));
761 762 763 764 765
	if (ref != NULL)
		ref->offset = offs;
	return ref;
}

766 767 768 769 770 771 772
/*
 * Convert a location into trace_arg.
 * If tvar == NULL, this just checks variable can be converted.
 */
static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
				     Dwarf_Op *fb_ops,
				     struct probe_trace_arg *tvar)
773
{
774 775 776
	Dwarf_Attribute attr;
	Dwarf_Op *op;
	size_t nops;
777 778
	unsigned int regn;
	Dwarf_Word offs = 0;
779
	bool ref = false;
780
	const char *regs;
781 782
	int ret;

783 784 785
	if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
		goto static_var;

786 787
	/* TODO: handle more than 1 exprs */
	if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL ||
788
	    dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0 ||
789 790 791 792 793 794
	    nops == 0) {
		/* TODO: Support const_value */
		return -ENOENT;
	}

	if (op->atom == DW_OP_addr) {
795
static_var:
796 797
		if (!tvar)
			return 0;
798 799 800 801 802 803 804 805 806 807 808
		/* 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;
	}
809 810

	/* If this is based on frame buffer, set the offset */
811
	if (op->atom == DW_OP_fbreg) {
812
		if (fb_ops == NULL)
813
			return -ENOTSUP;
814
		ref = true;
815
		offs = op->number;
816
		op = &fb_ops[0];
817
	}
818

819 820 821
	if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
		regn = op->atom - DW_OP_breg0;
		offs += op->number;
822
		ref = true;
823 824 825 826 827
	} 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;
828
		ref = true;
829 830
	} else if (op->atom == DW_OP_regx) {
		regn = op->number;
831
	} else {
832
		pr_debug("DW_OP %x is not supported.\n", op->atom);
833 834
		return -ENOTSUP;
	}
835

836 837 838
	if (!tvar)
		return 0;

839
	regs = get_arch_regstr(regn);
840
	if (!regs) {
841
		/* This should be a bug in DWARF or this tool */
M
Masami Hiramatsu 已提交
842 843
		pr_warning("Mapping for the register number %u "
			   "missing on this architecture.\n", regn);
844 845
		return -ERANGE;
	}
846

847 848 849 850
	tvar->value = strdup(regs);
	if (tvar->value == NULL)
		return -ENOMEM;

851
	if (ref) {
852
		tvar->ref = alloc_trace_arg_ref((long)offs);
853 854
		if (tvar->ref == NULL)
			return -ENOMEM;
855
	}
856
	return 0;
857 858
}

859 860
#define BYTES_TO_BITS(nb)	((nb) * BITS_PER_LONG / sizeof(long))

861
static int convert_variable_type(Dwarf_Die *vr_die,
862
				 struct probe_trace_arg *tvar,
863
				 const char *cast)
864
{
865
	struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
866 867 868 869
	Dwarf_Die type;
	char buf[16];
	int ret;

870 871 872 873 874 875 876
	/* 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;
	}

877 878 879 880 881 882 883 884
	if (die_get_bit_size(vr_die) != 0) {
		/* This is a bitfield */
		ret = snprintf(buf, 16, "b%d@%d/%zd", die_get_bit_size(vr_die),
				die_get_bit_offset(vr_die),
				BYTES_TO_BITS(die_get_byte_size(vr_die)));
		goto formatted;
	}

885 886 887 888 889
	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;
	}
890

891 892 893
	pr_debug("%s type is %s.\n",
		 dwarf_diename(vr_die), dwarf_diename(&type));

894 895 896 897 898
	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: "
M
Masami Hiramatsu 已提交
899
				   "%s(%s) is not a pointer nor array.\n",
900 901 902 903 904
				   dwarf_diename(vr_die), dwarf_diename(&type));
			return -EINVAL;
		}
		if (ret == DW_TAG_pointer_type) {
			if (die_get_real_type(&type, &type) == NULL) {
M
Masami Hiramatsu 已提交
905 906
				pr_warning("Failed to get a type"
					   " information.\n");
907 908 909 910 911
				return -ENOENT;
			}
			while (*ref_ptr)
				ref_ptr = &(*ref_ptr)->next;
			/* Add new reference with offset +0 */
912
			*ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
913 914 915 916 917
			if (*ref_ptr == NULL) {
				pr_warning("Out of memory error\n");
				return -ENOMEM;
			}
		}
918 919
		if (!die_compare_name(&type, "char") &&
		    !die_compare_name(&type, "unsigned char")) {
920
			pr_warning("Failed to cast into string: "
M
Masami Hiramatsu 已提交
921
				   "%s is not (unsigned) char *.\n",
922 923 924 925 926 927 928
				   dwarf_diename(vr_die));
			return -EINVAL;
		}
		tvar->type = strdup(cast);
		return (tvar->type == NULL) ? -ENOMEM : 0;
	}

929 930 931 932
	ret = BYTES_TO_BITS(die_get_byte_size(&type));
	if (!ret)
		/* No size ... try to use default type */
		return 0;
933

934 935 936 937 938
	/* 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;
939
	}
940 941 942 943 944 945 946 947 948 949 950 951 952 953
	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",
			   strerror(-ret));
		return ret;
	}
	tvar->type = strdup(buf);
	if (tvar->type == NULL)
		return -ENOMEM;
954
	return 0;
955 956
}

957
static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
958
				    struct perf_probe_arg_field *field,
959
				    struct probe_trace_arg_ref **ref_ptr,
960
				    Dwarf_Die *die_mem)
961
{
962
	struct probe_trace_arg_ref *ref = *ref_ptr;
963 964
	Dwarf_Die type;
	Dwarf_Word offs;
965
	int ret, tag;
966 967

	pr_debug("converting %s in %s\n", field->name, varname);
968 969 970 971
	if (die_get_real_type(vr_die, &type) == NULL) {
		pr_warning("Failed to get the type of %s.\n", varname);
		return -ENOENT;
	}
972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987
	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) {
988
			ref = zalloc(sizeof(struct probe_trace_arg_ref));
989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002
			if (ref == NULL)
				return -ENOMEM;
			if (*ref_ptr)
				(*ref_ptr)->next = ref;
			else
				*ref_ptr = ref;
		}
		ref->offset += die_get_byte_size(&type) * field->index;
		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 */
1003 1004 1005 1006 1007
		if (!field->ref) {
			pr_err("Semantic error: %s must be referred by '->'\n",
			       field->name);
			return -EINVAL;
		}
1008
		/* Get the type pointed by this pointer */
1009 1010 1011 1012
		if (die_get_real_type(&type, &type) == NULL) {
			pr_warning("Failed to get the type of %s.\n", varname);
			return -ENOENT;
		}
1013
		/* Verify it is a data structure  */
1014 1015 1016 1017
		if (dwarf_tag(&type) != DW_TAG_structure_type) {
			pr_warning("%s is not a data structure.\n", varname);
			return -EINVAL;
		}
1018

1019
		ref = zalloc(sizeof(struct probe_trace_arg_ref));
1020 1021
		if (ref == NULL)
			return -ENOMEM;
1022 1023 1024 1025 1026
		if (*ref_ptr)
			(*ref_ptr)->next = ref;
		else
			*ref_ptr = ref;
	} else {
1027
		/* Verify it is a data structure  */
1028
		if (tag != DW_TAG_structure_type) {
1029 1030 1031
			pr_warning("%s is not a data structure.\n", varname);
			return -EINVAL;
		}
1032
		if (field->name[0] == '[') {
M
Masami Hiramatsu 已提交
1033 1034
			pr_err("Semantic error: %s is not a pointor"
			       " nor array.\n", varname);
1035 1036
			return -EINVAL;
		}
1037 1038 1039 1040 1041 1042 1043 1044 1045 1046
		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;
		}
1047 1048
	}

1049 1050 1051 1052 1053
	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;
	}
1054 1055

	/* Get the offset of the field */
1056 1057
	ret = die_get_data_member_location(die_mem, &offs);
	if (ret < 0) {
1058
		pr_warning("Failed to get the offset of %s.\n", field->name);
1059
		return ret;
1060
	}
1061 1062
	ref->offset += (long)offs;

1063
next:
1064 1065
	/* Converting next field */
	if (field->next)
1066
		return convert_variable_fields(die_mem, field->name,
1067
					field->next, &ref, die_mem);
1068 1069
	else
		return 0;
1070 1071
}

1072
/* Show a variables in kprobe event format */
1073
static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
1074
{
1075
	Dwarf_Die die_mem;
1076 1077
	int ret;

1078 1079
	pr_debug("Converting variable %s into trace event.\n",
		 dwarf_diename(vr_die));
1080

1081 1082 1083 1084 1085 1086 1087 1088
	ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
					pf->tvar);
	if (ret == -ENOENT)
		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");
	else if (pf->pvar->field) {
1089 1090 1091
		ret = convert_variable_fields(vr_die, pf->pvar->var,
					      pf->pvar->field, &pf->tvar->ref,
					      &die_mem);
1092 1093
		vr_die = &die_mem;
	}
1094 1095
	if (ret == 0)
		ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
1096
	/* *expr will be cached in libdw. Don't free it. */
1097
	return ret;
1098 1099 1100
}

/* Find a variable in a subprogram die */
1101
static int find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
1102
{
1103
	Dwarf_Die vr_die, *scopes;
1104
	char buf[32], *ptr;
1105
	int ret, nscopes;
1106

1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125
	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;
	}

1126
	if (pf->pvar->name)
1127
		pf->tvar->name = strdup(pf->pvar->name);
1128
	else {
1129 1130 1131
		ret = synthesize_perf_probe_arg(pf->pvar, buf, 32);
		if (ret < 0)
			return ret;
1132 1133 1134
		ptr = strchr(buf, ':');	/* Change type separator to _ */
		if (ptr)
			*ptr = '_';
1135
		pf->tvar->name = strdup(buf);
1136
	}
1137 1138
	if (pf->tvar->name == NULL)
		return -ENOMEM;
1139

1140 1141 1142
	pr_debug("Searching '%s' variable in context.\n",
		 pf->pvar->var);
	/* Search child die for local variables and parameters. */
1143
	if (die_find_variable_at(sp_die, pf->pvar->var, pf->addr, &vr_die))
1144 1145 1146 1147
		ret = convert_variable(&vr_die, pf);
	else {
		/* Search upper class */
		nscopes = dwarf_getscopes_die(sp_die, &scopes);
1148 1149 1150 1151 1152 1153 1154
		while (nscopes-- > 1) {
			pr_debug("Searching variables in %s\n",
				 dwarf_diename(&scopes[nscopes]));
			/* We should check this scope, so give dummy address */
			if (die_find_variable_at(&scopes[nscopes],
						 pf->pvar->var, 0,
						 &vr_die)) {
1155
				ret = convert_variable(&vr_die, pf);
1156 1157 1158 1159
				goto found;
			}
		}
		if (scopes)
1160
			free(scopes);
1161
		ret = -ENOENT;
1162
	}
1163
found:
1164
	if (ret < 0)
1165 1166
		pr_warning("Failed to find '%s' in this function.\n",
			   pf->pvar->var);
1167
	return ret;
1168 1169
}

1170 1171 1172
/* Convert subprogram DIE to trace point */
static int convert_to_trace_point(Dwarf_Die *sp_die, Dwarf_Addr paddr,
				  bool retprobe, struct probe_trace_point *tp)
1173
{
1174
	Dwarf_Addr eaddr;
1175
	const char *name;
1176

1177
	/* Copy the name of probe point */
1178 1179
	name = dwarf_diename(sp_die);
	if (name) {
1180
		if (dwarf_entrypc(sp_die, &eaddr) != 0) {
M
Masami Hiramatsu 已提交
1181
			pr_warning("Failed to get entry address of %s\n",
1182 1183 1184
				   dwarf_diename(sp_die));
			return -ENOENT;
		}
1185 1186
		tp->symbol = strdup(name);
		if (tp->symbol == NULL)
1187
			return -ENOMEM;
1188
		tp->offset = (unsigned long)(paddr - eaddr);
1189
	} else
1190
		/* This function has no name. */
1191
		tp->offset = (unsigned long)paddr;
1192

1193
	/* Return probe must be on the head of a subprogram */
1194 1195
	if (retprobe) {
		if (eaddr != paddr) {
1196
			pr_warning("Return probe must be on the head of"
M
Masami Hiramatsu 已提交
1197
				   " a real function.\n");
1198 1199
			return -EINVAL;
		}
1200
		tp->retprobe = true;
1201 1202
	}

1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223
	return 0;
}

/* Call probe_finder callback with real subprogram DIE */
static int call_probe_finder(Dwarf_Die *sp_die, struct probe_finder *pf)
{
	Dwarf_Die die_mem;
	Dwarf_Attribute fb_attr;
	size_t nops;
	int ret;

	/* If no real subprogram, find a real one */
	if (!sp_die || dwarf_tag(sp_die) != DW_TAG_subprogram) {
		sp_die = die_find_real_subprogram(&pf->cu_die,
						  pf->addr, &die_mem);
		if (!sp_die) {
			pr_warning("Failed to find probe point in any "
				   "functions.\n");
			return -ENOENT;
		}
	}
1224

1225 1226
	/* Get the frame base attribute/ops */
	dwarf_attr(sp_die, DW_AT_frame_base, &fb_attr);
1227
	ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
1228
	if (ret <= 0 || nops == 0) {
1229
		pf->fb_ops = NULL;
1230
#if _ELFUTILS_PREREQ(0, 142)
1231 1232 1233
	} else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
		   pf->cfi != NULL) {
		Dwarf_Frame *frame;
1234 1235
		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
1236
			pr_warning("Failed to get call frame on 0x%jx\n",
1237 1238 1239
				   (uintmax_t)pf->addr);
			return -ENOENT;
		}
1240
#endif
1241
	}
1242

1243 1244
	/* Call finder's callback handler */
	ret = pf->callback(sp_die, pf);
1245 1246 1247

	/* *pf->fb_ops will be cached in libdw. Don't free it. */
	pf->fb_ops = NULL;
1248 1249

	return ret;
1250 1251
}

1252 1253
static int probe_point_line_walker(const char *fname, int lineno,
				   Dwarf_Addr addr, void *data)
1254
{
1255 1256
	struct probe_finder *pf = data;
	int ret;
1257

1258 1259
	if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
		return 0;
1260

1261 1262
	pf->addr = addr;
	ret = call_probe_finder(NULL, pf);
1263

1264
	/* Continue if no error, because the line will be in inline function */
1265
	return ret < 0 ? ret : 0;
1266
}
1267

1268 1269 1270 1271
/* 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);
1272 1273
}

1274 1275 1276 1277
/* Find lines which match lazy pattern */
static int find_lazy_match_lines(struct list_head *head,
				 const char *fname, const char *pat)
{
1278 1279 1280 1281 1282 1283 1284 1285 1286
	FILE *fp;
	char *line = NULL;
	size_t line_len;
	ssize_t len;
	int count = 0, linenum = 1;

	fp = fopen(fname, "r");
	if (!fp) {
		pr_warning("Failed to open %s: %s\n", fname, strerror(errno));
1287
		return -errno;
1288 1289
	}

1290
	while ((len = getline(&line, &line_len, fp)) > 0) {
1291

1292 1293 1294 1295 1296 1297
		if (line[len - 1] == '\n')
			line[len - 1] = '\0';

		if (strlazymatch(line, pat)) {
			line_list__add_line(head, linenum);
			count++;
1298
		}
1299
		linenum++;
1300
	}
1301 1302 1303 1304 1305 1306 1307 1308 1309

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

	if (count == 0)
		pr_debug("No matched lines found in %s.\n", fname);
	return count;
1310 1311
}

1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330
static int probe_point_lazy_walker(const char *fname, int lineno,
				   Dwarf_Addr addr, void *data)
{
	struct probe_finder *pf = data;
	int ret;

	if (!line_list__has_line(&pf->lcache, lineno) ||
	    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;
	ret = call_probe_finder(NULL, pf);

	/*
	 * Continue if no error, because the lazy pattern will match
	 * to other lines
	 */
1331
	return ret < 0 ? ret : 0;
1332 1333
}

1334
/* Find probe points from lazy pattern  */
1335
static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
1336
{
1337
	int ret = 0;
1338 1339 1340 1341

	if (list_empty(&pf->lcache)) {
		/* Matching lazy line pattern */
		ret = find_lazy_match_lines(&pf->lcache, pf->fname,
1342
					    pf->pev->point.lazy_line);
1343
		if (ret <= 0)
1344
			return ret;
1345 1346
	}

1347
	return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
1348 1349
}

1350 1351 1352 1353 1354 1355
/* Callback parameter with return value */
struct dwarf_callback_param {
	void *data;
	int retval;
};

1356 1357
static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
{
1358 1359
	struct dwarf_callback_param *param = data;
	struct probe_finder *pf = param->data;
1360
	struct perf_probe_point *pp = &pf->pev->point;
1361
	Dwarf_Addr addr;
1362

1363
	if (pp->lazy_line)
1364
		param->retval = find_probe_point_lazy(in_die, pf);
1365 1366
	else {
		/* Get probe address */
1367
		if (dwarf_entrypc(in_die, &addr) != 0) {
M
Masami Hiramatsu 已提交
1368
			pr_warning("Failed to get entry address of %s.\n",
1369 1370 1371 1372 1373
				   dwarf_diename(in_die));
			param->retval = -ENOENT;
			return DWARF_CB_ABORT;
		}
		pf->addr = addr;
1374 1375 1376 1377
		pf->addr += pp->offset;
		pr_debug("found inline addr: 0x%jx\n",
			 (uintmax_t)pf->addr);

1378
		param->retval = call_probe_finder(in_die, pf);
1379 1380
		if (param->retval < 0)
			return DWARF_CB_ABORT;
1381
	}
1382 1383 1384

	return DWARF_CB_OK;
}
1385

1386
/* Search function from function name */
1387
static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
1388
{
1389 1390
	struct dwarf_callback_param *param = data;
	struct probe_finder *pf = param->data;
1391
	struct perf_probe_point *pp = &pf->pev->point;
1392

1393 1394
	/* Check tag and diename */
	if (dwarf_tag(sp_die) != DW_TAG_subprogram ||
1395
	    !die_compare_name(sp_die, pp->function))
1396
		return DWARF_CB_OK;
1397

1398 1399 1400 1401
	/* Check declared file */
	if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
		return DWARF_CB_OK;

1402
	pf->fname = dwarf_decl_file(sp_die);
1403 1404 1405
	if (pp->line) { /* Function relative line */
		dwarf_decl_line(sp_die, &pf->lno);
		pf->lno += pp->line;
1406
		param->retval = find_probe_point_by_line(pf);
1407 1408
	} else if (!dwarf_func_inline(sp_die)) {
		/* Real function */
1409
		if (pp->lazy_line)
1410
			param->retval = find_probe_point_lazy(sp_die, pf);
1411
		else {
1412
			if (dwarf_entrypc(sp_die, &pf->addr) != 0) {
M
Masami Hiramatsu 已提交
1413 1414
				pr_warning("Failed to get entry address of "
					   "%s.\n", dwarf_diename(sp_die));
1415 1416 1417
				param->retval = -ENOENT;
				return DWARF_CB_ABORT;
			}
1418 1419
			pf->addr += pp->offset;
			/* TODO: Check the address in this function */
1420
			param->retval = call_probe_finder(sp_die, pf);
1421
		}
1422 1423 1424
	} else {
		struct dwarf_callback_param _param = {.data = (void *)pf,
						      .retval = 0};
1425
		/* Inlined function: search instances */
1426 1427 1428 1429
		dwarf_func_inline_instances(sp_die, probe_point_inline_cb,
					    &_param);
		param->retval = _param.retval;
	}
1430

1431
	return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1432 1433
}

1434
static int find_probe_point_by_func(struct probe_finder *pf)
1435
{
1436 1437 1438 1439
	struct dwarf_callback_param _param = {.data = (void *)pf,
					      .retval = 0};
	dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
	return _param.retval;
1440 1441
}

1442 1443
/* Find probe points from debuginfo */
static int find_probes(int fd, struct probe_finder *pf)
1444
{
1445
	struct perf_probe_point *pp = &pf->pev->point;
1446 1447 1448
	Dwarf_Off off, noff;
	size_t cuhl;
	Dwarf_Die *diep;
1449 1450 1451
	Dwarf *dbg = NULL;
	Dwfl *dwfl;
	Dwarf_Addr bias;	/* Currently ignored */
1452
	int ret = 0;
1453

1454
	dbg = dwfl_init_offline_dwarf(fd, &dwfl, &bias);
1455
	if (!dbg) {
M
Masami Hiramatsu 已提交
1456
		pr_warning("No debug information found in the vmlinux - "
1457
			"please rebuild with CONFIG_DEBUG_INFO=y.\n");
1458
		close(fd);	/* Without dwfl_end(), fd isn't closed. */
1459 1460
		return -EBADF;
	}
1461

1462
#if _ELFUTILS_PREREQ(0, 142)
1463
	/* Get the call frame information from this dwarf */
1464
	pf->cfi = dwarf_getcfi(dbg);
1465
#endif
1466

1467
	off = 0;
1468
	line_list__init(&pf->lcache);
1469
	/* Loop on CUs (Compilation Unit) */
1470
	while (!dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1471
		/* Get the DIE(Debugging Information Entry) of this CU */
1472
		diep = dwarf_offdie(dbg, off + cuhl, &pf->cu_die);
1473 1474
		if (!diep)
			continue;
1475 1476 1477

		/* Check if target file is included. */
		if (pp->file)
1478
			pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1479
		else
1480
			pf->fname = NULL;
1481

1482
		if (!pp->file || pf->fname) {
1483
			if (pp->function)
1484
				ret = find_probe_point_by_func(pf);
1485
			else if (pp->lazy_line)
1486
				ret = find_probe_point_lazy(NULL, pf);
1487
			else {
1488 1489
				pf->lno = pp->line;
				ret = find_probe_point_by_line(pf);
1490
			}
1491
			if (ret < 0)
1492
				break;
1493
		}
1494
		off = noff;
1495
	}
1496
	line_list__free(&pf->lcache);
1497 1498
	if (dwfl)
		dwfl_end(dwfl);
1499

1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588
	return ret;
}

/* Add a found probe point into trace event list */
static int add_probe_trace_event(Dwarf_Die *sp_die, struct probe_finder *pf)
{
	struct trace_event_finder *tf =
			container_of(pf, struct trace_event_finder, pf);
	struct probe_trace_event *tev;
	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++];

	ret = convert_to_trace_point(sp_die, pf->addr, pf->pev->point.retprobe,
				     &tev->point);
	if (ret < 0)
		return ret;

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

	/* Find each argument */
	tev->nargs = pf->pev->nargs;
	tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
	if (tev->args == NULL)
		return -ENOMEM;
	for (i = 0; i < pf->pev->nargs; i++) {
		pf->pvar = &pf->pev->args[i];
		pf->tvar = &tev->args[i];
		ret = find_variable(sp_die, pf);
		if (ret != 0)
			return ret;
	}

	return 0;
}

/* Find probe_trace_events specified by perf_probe_event from debuginfo */
int find_probe_trace_events(int fd, struct perf_probe_event *pev,
			    struct probe_trace_event **tevs, int max_tevs)
{
	struct trace_event_finder tf = {
			.pf = {.pev = pev, .callback = add_probe_trace_event},
			.max_tevs = max_tevs};
	int ret;

	/* Allocate result tevs array */
	*tevs = zalloc(sizeof(struct probe_trace_event) * max_tevs);
	if (*tevs == NULL)
		return -ENOMEM;

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

	ret = find_probes(fd, &tf.pf);
	if (ret < 0) {
		free(*tevs);
		*tevs = NULL;
		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,
						af->pf.fb_ops, NULL);
		if (ret == 0) {
			ret = die_get_varname(die_mem, buf, MAX_VAR_LEN);
1589
			pr_debug2("Add new var: %s\n", buf);
1590 1591 1592 1593 1594
			if (ret > 0)
				strlist__add(vl->vars, buf);
		}
	}

1595
	if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606
		return DIE_FIND_CB_CONTINUE;
	else
		return DIE_FIND_CB_SIBLING;
}

/* Add a found vars into available variables list */
static int add_available_vars(Dwarf_Die *sp_die, struct probe_finder *pf)
{
	struct available_var_finder *af =
			container_of(pf, struct available_var_finder, pf);
	struct variable_list *vl;
1607 1608
	Dwarf_Die die_mem, *scopes = NULL;
	int ret, nscopes;
1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628

	/* 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++];

	ret = convert_to_trace_point(sp_die, pf->addr, pf->pev->point.retprobe,
				     &vl->point);
	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;
1629
	af->child = true;
1630 1631
	die_find_child(sp_die, collect_variables_cb, (void *)af, &die_mem);

1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644
	/* Find external variables */
	if (!af->externs)
		goto out;
	/* Don't need to search child DIE for externs. */
	af->child = false;
	nscopes = dwarf_getscopes_die(sp_die, &scopes);
	while (nscopes-- > 1)
		die_find_child(&scopes[nscopes], collect_variables_cb,
			       (void *)af, &die_mem);
	if (scopes)
		free(scopes);

out:
1645 1646 1647 1648 1649 1650 1651 1652 1653 1654
	if (strlist__empty(vl->vars)) {
		strlist__delete(vl->vars);
		vl->vars = NULL;
	}

	return ret;
}

/* Find available variables at given probe point */
int find_available_vars_at(int fd, struct perf_probe_event *pev,
1655 1656
			   struct variable_list **vls, int max_vls,
			   bool externs)
1657 1658 1659
{
	struct available_var_finder af = {
			.pf = {.pev = pev, .callback = add_available_vars},
1660
			.max_vls = max_vls, .externs = externs};
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
	int ret;

	/* Allocate result vls array */
	*vls = zalloc(sizeof(struct variable_list) * max_vls);
	if (*vls == NULL)
		return -ENOMEM;

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

	ret = find_probes(fd, &af.pf);
	if (ret < 0) {
		/* Free vlist for error */
		while (af.nvls--) {
			if (af.vls[af.nvls].point.symbol)
				free(af.vls[af.nvls].point.symbol);
			if (af.vls[af.nvls].vars)
				strlist__delete(af.vls[af.nvls].vars);
		}
		free(af.vls);
		*vls = NULL;
		return ret;
	}

	return (ret < 0) ? ret : af.nvls;
1686 1687
}

1688
/* Reverse search */
1689
int find_perf_probe_point(unsigned long addr, struct perf_probe_point *ppt)
1690 1691
{
	Dwarf_Die cudie, spdie, indie;
1692 1693
	Dwarf *dbg = NULL;
	Dwfl *dwfl = NULL;
1694
	Dwarf_Line *line;
1695
	Dwarf_Addr laddr, eaddr, bias = 0;
1696 1697
	const char *tmp;
	int lineno, ret = 0;
1698
	bool found = false;
1699

1700 1701 1702
	/* Open the live linux kernel */
	dbg = dwfl_init_live_kernel_dwarf(addr, &dwfl, &bias);
	if (!dbg) {
M
Masami Hiramatsu 已提交
1703
		pr_warning("No debug information found in the vmlinux - "
1704 1705 1706 1707
			"please rebuild with CONFIG_DEBUG_INFO=y.\n");
		ret = -EINVAL;
		goto end;
	}
1708

1709 1710
	/* Adjust address with bias */
	addr += bias;
1711
	/* Find cu die */
1712
	if (!dwarf_addrdie(dbg, (Dwarf_Addr)addr - bias, &cudie)) {
M
Masami Hiramatsu 已提交
1713 1714
		pr_warning("Failed to find debug information for address %lx\n",
			   addr);
1715 1716 1717
		ret = -EINVAL;
		goto end;
	}
1718 1719 1720 1721

	/* Find a corresponding line */
	line = dwarf_getsrc_die(&cudie, (Dwarf_Addr)addr);
	if (line) {
1722 1723 1724
		if (dwarf_lineaddr(line, &laddr) == 0 &&
		    (Dwarf_Addr)addr == laddr &&
		    dwarf_lineno(line, &lineno) == 0) {
1725
			tmp = dwarf_linesrc(line, NULL, NULL);
1726 1727
			if (tmp) {
				ppt->line = lineno;
1728 1729 1730 1731 1732
				ppt->file = strdup(tmp);
				if (ppt->file == NULL) {
					ret = -ENOMEM;
					goto end;
				}
1733 1734
				found = true;
			}
1735 1736 1737 1738 1739 1740
		}
	}

	/* Find a corresponding function */
	if (die_find_real_subprogram(&cudie, (Dwarf_Addr)addr, &spdie)) {
		tmp = dwarf_diename(&spdie);
1741
		if (!tmp || dwarf_entrypc(&spdie, &eaddr) != 0)
1742 1743
			goto end;

1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763
		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;
			}
1764
		}
1765 1766 1767
		/* We don't have a line number, let's use offset */
		ppt->offset = addr - (unsigned long)eaddr;
found:
1768 1769 1770 1771 1772
		ppt->function = strdup(tmp);
		if (ppt->function == NULL) {
			ret = -ENOMEM;
			goto end;
		}
1773
		found = true;
1774 1775 1776
	}

end:
1777 1778
	if (dwfl)
		dwfl_end(dwfl);
1779 1780
	if (ret >= 0)
		ret = found ? 1 : 0;
1781 1782 1783
	return ret;
}

1784 1785 1786 1787
/* Add a line and store the src path */
static int line_range_add_line(const char *src, unsigned int lineno,
			       struct line_range *lr)
{
1788
	/* Copy source path */
1789
	if (!lr->path) {
1790 1791 1792
		lr->path = strdup(src);
		if (lr->path == NULL)
			return -ENOMEM;
1793 1794 1795 1796
	}
	return line_list__add_line(&lr->line_list, lineno);
}

1797 1798 1799
static int line_range_walk_cb(const char *fname, int lineno,
			      Dwarf_Addr addr __used,
			      void *data)
1800
{
1801
	struct line_finder *lf = data;
1802

1803
	if ((strtailcmp(fname, lf->fname) != 0) ||
1804
	    (lf->lno_s > lineno || lf->lno_e < lineno))
1805
		return 0;
1806

1807 1808
	if (line_range_add_line(fname, lineno, lf->lr) < 0)
		return -EINVAL;
1809

1810
	return 0;
1811
}
1812

1813
/* Find line range from its line number */
1814
static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1815
{
1816
	int ret;
1817

1818
	ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1819

1820
	/* Update status */
1821 1822 1823 1824 1825
	if (ret >= 0)
		if (!list_empty(&lf->lr->line_list))
			ret = lf->found = 1;
		else
			ret = 0;	/* Lines are not found */
1826 1827 1828 1829
	else {
		free(lf->lr->path);
		lf->lr->path = NULL;
	}
1830
	return ret;
1831 1832
}

1833 1834
static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
{
1835 1836 1837
	struct dwarf_callback_param *param = data;

	param->retval = find_line_range_by_line(in_die, param->data);
1838 1839 1840
	return DWARF_CB_ABORT;	/* No need to find other instances */
}

1841
/* Search function from function name */
1842
static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1843
{
1844 1845
	struct dwarf_callback_param *param = data;
	struct line_finder *lf = param->data;
1846 1847
	struct line_range *lr = lf->lr;

1848 1849 1850 1851
	/* Check declared file */
	if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
		return DWARF_CB_OK;

1852
	if (dwarf_tag(sp_die) == DW_TAG_subprogram &&
1853
	    die_compare_name(sp_die, lr->function)) {
1854 1855
		lf->fname = dwarf_decl_file(sp_die);
		dwarf_decl_line(sp_die, &lr->offset);
1856
		pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1857
		lf->lno_s = lr->offset + lr->start;
1858 1859 1860 1861
		if (lf->lno_s < 0)	/* Overflow */
			lf->lno_s = INT_MAX;
		lf->lno_e = lr->offset + lr->end;
		if (lf->lno_e < 0)	/* Overflow */
1862
			lf->lno_e = INT_MAX;
1863
		pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1864 1865
		lr->start = lf->lno_s;
		lr->end = lf->lno_e;
1866 1867 1868 1869
		if (dwarf_func_inline(sp_die)) {
			struct dwarf_callback_param _param;
			_param.data = (void *)lf;
			_param.retval = 0;
1870
			dwarf_func_inline_instances(sp_die,
1871 1872 1873 1874 1875 1876
						    line_range_inline_cb,
						    &_param);
			param->retval = _param.retval;
		} else
			param->retval = find_line_range_by_line(sp_die, lf);
		return DWARF_CB_ABORT;
1877
	}
1878
	return DWARF_CB_OK;
1879 1880
}

1881
static int find_line_range_by_func(struct line_finder *lf)
1882
{
1883 1884 1885
	struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
	dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
	return param.retval;
1886 1887 1888 1889
}

int find_line_range(int fd, struct line_range *lr)
{
1890
	struct line_finder lf = {.lr = lr, .found = 0};
1891
	int ret = 0;
1892 1893 1894
	Dwarf_Off off = 0, noff;
	size_t cuhl;
	Dwarf_Die *diep;
1895 1896 1897
	Dwarf *dbg = NULL;
	Dwfl *dwfl;
	Dwarf_Addr bias;	/* Currently ignored */
1898
	const char *comp_dir;
1899

1900
	dbg = dwfl_init_offline_dwarf(fd, &dwfl, &bias);
1901
	if (!dbg) {
M
Masami Hiramatsu 已提交
1902
		pr_warning("No debug information found in the vmlinux - "
1903
			"please rebuild with CONFIG_DEBUG_INFO=y.\n");
1904
		close(fd);	/* Without dwfl_end(), fd isn't closed. */
1905 1906
		return -EBADF;
	}
1907

1908
	/* Loop on CUs (Compilation Unit) */
1909 1910
	while (!lf.found && ret >= 0) {
		if (dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL) != 0)
1911 1912 1913
			break;

		/* Get the DIE(Debugging Information Entry) of this CU */
1914 1915 1916
		diep = dwarf_offdie(dbg, off + cuhl, &lf.cu_die);
		if (!diep)
			continue;
1917 1918 1919

		/* Check if target file is included. */
		if (lr->file)
1920
			lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1921
		else
1922
			lf.fname = 0;
1923

1924
		if (!lr->file || lf.fname) {
1925
			if (lr->function)
1926
				ret = find_line_range_by_func(&lf);
1927 1928
			else {
				lf.lno_s = lr->start;
1929
				lf.lno_e = lr->end;
1930
				ret = find_line_range_by_line(NULL, &lf);
1931 1932
			}
		}
1933
		off = noff;
1934
	}
1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945

	/* 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;
		}
	}

1946
	pr_debug("path: %s\n", lr->path);
1947
	dwfl_end(dwfl);
1948
	return (ret < 0) ? ret : lf.found;
1949 1950
}