Пример #1
0
static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
{
	struct find_scope_param *fsp = data;
	const char *file;
	int lno;

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

	
	if (fsp->file) {
		file = dwarf_decl_file(fn_die);
		if (!file || strcmp(fsp->file, file) != 0)
			return 0;
	}
	
	if (fsp->function) {
		if (die_compare_name(fn_die, fsp->function)) {
			memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
			fsp->found = true;
			return 1;
		}
	} else {
		
		dwarf_decl_line(fn_die, &lno);
		if (lno < fsp->line && fsp->diff > fsp->line - lno) {
			
			fsp->diff = fsp->line - lno;
			memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
			fsp->found = true;
		}
	}
	return 0;
}
static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
{
	struct dwarf_callback_param *param = data;
	struct line_finder *lf = param->data;
	struct line_range *lr = lf->lr;

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

	if (dwarf_tag(sp_die) == DW_TAG_subprogram &&
	    die_compare_name(sp_die, lr->function)) {
		lf->fname = dwarf_decl_file(sp_die);
		dwarf_decl_line(sp_die, &lr->offset);
		pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
		lf->lno_s = lr->offset + lr->start;
		if (lf->lno_s < 0)	
			lf->lno_s = INT_MAX;
		lf->lno_e = lr->offset + lr->end;
		if (lf->lno_e < 0)	
			lf->lno_e = INT_MAX;
		pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
		lr->start = lf->lno_s;
		lr->end = lf->lno_e;
		if (dwarf_func_inline(sp_die))
			param->retval = die_walk_instances(sp_die,
						line_range_inline_cb, lf);
		else
			param->retval = find_line_range_by_line(sp_die, lf);
		return DWARF_CB_ABORT;
	}
	return DWARF_CB_OK;
}
Пример #4
0
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;
}
Пример #5
0
static int __die_find_variable_cb(Dwarf_Die *die_mem, void *data)
{
	const char *name = data;
	int tag;

	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;
}
static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
{
	struct dwarf_callback_param *param = data;
	struct probe_finder *pf = param->data;
	struct perf_probe_point *pp = &pf->pev->point;
	Dwarf_Attribute attr;

	
	if (dwarf_tag(sp_die) != DW_TAG_subprogram ||
	    !die_compare_name(sp_die, pp->function) ||
	    dwarf_attr(sp_die, DW_AT_declaration, &attr))
		return DWARF_CB_OK;

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

	pf->fname = dwarf_decl_file(sp_die);
	if (pp->line) { 
		dwarf_decl_line(sp_die, &pf->lno);
		pf->lno += pp->line;
		param->retval = find_probe_point_by_line(pf);
	} else if (!dwarf_func_inline(sp_die)) {
		
		if (pp->lazy_line)
			param->retval = find_probe_point_lazy(sp_die, pf);
		else {
			if (dwarf_entrypc(sp_die, &pf->addr) != 0) {
				pr_warning("Failed to get entry address of "
					   "%s.\n", dwarf_diename(sp_die));
				param->retval = -ENOENT;
				return DWARF_CB_ABORT;
			}
			pf->addr += pp->offset;
			
			param->retval = call_probe_finder(sp_die, pf);
		}
	} else
		
		param->retval = die_walk_instances(sp_die,
					probe_point_inline_cb, (void *)pf);

	return DWARF_CB_ABORT; 
}
Пример #7
0
/* Search function from function name */
static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
{
	struct dwarf_callback_param *param = data;
	struct probe_finder *pf = param->data;
	struct perf_probe_point *pp = &pf->pev->point;

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

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

	pf->fname = dwarf_decl_file(sp_die);
	if (pp->line) { /* Function relative line */
		dwarf_decl_line(sp_die, &pf->lno);
		pf->lno += pp->line;
		param->retval = find_probe_point_by_line(pf);
	} else if (!dwarf_func_inline(sp_die)) {
		/* Real function */
		if (pp->lazy_line)
			param->retval = find_probe_point_lazy(sp_die, pf);
		else {
			if (dwarf_entrypc(sp_die, &pf->addr) != 0) {
				pr_warning("Failed to get entry address of "
					   "%s.\n", dwarf_diename(sp_die));
				param->retval = -ENOENT;
				return DWARF_CB_ABORT;
			}
			pf->addr += pp->offset;
			/* TODO: Check the address in this function */
			param->retval = call_probe_finder(sp_die, pf);
		}
	} else
		/* Inlined function: search instances */
		param->retval = die_walk_instances(sp_die,
					probe_point_inline_cb, (void *)pf);

	return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
}
static int find_probe_point_by_func(struct probe_finder *pf)
{
	struct dwarf_callback_param _param = {.data = (void *)pf,
					      .retval = 0};
	dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
	return _param.retval;
}

struct pubname_callback_param {
	char *function;
	char *file;
	Dwarf_Die *cu_die;
	Dwarf_Die *sp_die;
	int found;
};

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

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

		if (die_compare_name(param->sp_die, param->function)) {
			if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
				return DWARF_CB_OK;

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

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

	return DWARF_CB_OK;
}

static int debuginfo__find_probes(struct debuginfo *self,
				  struct probe_finder *pf)
{
	struct perf_probe_point *pp = &pf->pev->point;
	Dwarf_Off off, noff;
	size_t cuhl;
	Dwarf_Die *diep;
	int ret = 0;

#if _ELFUTILS_PREREQ(0, 142)
	
	pf->cfi = dwarf_getcfi(self->dbg);
#endif

	off = 0;
	line_list__init(&pf->lcache);

	
	if (pp->function) {
		struct pubname_callback_param pubname_param = {
			.function = pp->function,
			.file	  = pp->file,
			.cu_die	  = &pf->cu_die,
			.sp_die	  = &pf->sp_die,
			.found	  = 0,
		};
		struct dwarf_callback_param probe_param = {
			.data = pf,
		};

		dwarf_getpubnames(self->dbg, pubname_search_cb,
				  &pubname_param, 0);
		if (pubname_param.found) {
			ret = probe_point_search_cb(&pf->sp_die, &probe_param);
			if (ret)
				goto found;
		}
	}

	
	while (!dwarf_nextcu(self->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
		
		diep = dwarf_offdie(self->dbg, off + cuhl, &pf->cu_die);
		if (!diep)
			continue;

		
		if (pp->file)
			pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
		else
			pf->fname = NULL;

		if (!pp->file || pf->fname) {
			if (pp->function)
				ret = find_probe_point_by_func(pf);
			else if (pp->lazy_line)
				ret = find_probe_point_lazy(NULL, pf);
			else {
				pf->lno = pp->line;
				ret = find_probe_point_by_line(pf);
			}
			if (ret < 0)
				break;
		}
		off = noff;
	}

found:
	line_list__free(&pf->lcache);

	return ret;
}

static int add_probe_trace_event(Dwarf_Die *sc_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;

	
	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(&pf->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);

	
	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(sc_die, pf);
		if (ret != 0)
			return ret;
	}

	return 0;
}

int debuginfo__find_trace_events(struct debuginfo *self,
				 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;

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

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

	ret = debuginfo__find_probes(self, &tf.pf);
	if (ret < 0) {
		free(*tevs);
		*tevs = NULL;
		return ret;
	}

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

#define MAX_VAR_LEN 64

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);
			pr_debug2("Add new var: %s\n", buf);
			if (ret > 0)
				strlist__add(vl->vars, buf);
		}
	}

	if (af->child && dwarf_haspc(die_mem, af->pf.addr))
		return DIE_FIND_CB_CONTINUE;
	else
		return DIE_FIND_CB_SIBLING;
}

static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
{
	struct available_var_finder *af =
			container_of(pf, struct available_var_finder, pf);
	struct variable_list *vl;
	Dwarf_Die die_mem;
	int ret;

	
	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(&pf->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);

	
	vl->vars = strlist__new(true, NULL);
	if (vl->vars == NULL)
		return -ENOMEM;
	af->child = true;
	die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);

	
	if (!af->externs)
		goto out;
	
	af->child = false;
	die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);

out:
	if (strlist__empty(vl->vars)) {
		strlist__delete(vl->vars);
		vl->vars = NULL;
	}

	return ret;
}

int debuginfo__find_available_vars_at(struct debuginfo *self,
				      struct perf_probe_event *pev,
				      struct variable_list **vls,
				      int max_vls, bool externs)
{
	struct available_var_finder af = {
			.pf = {.pev = pev, .callback = add_available_vars},
			.max_vls = max_vls, .externs = externs};
	int ret;

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

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

	ret = debuginfo__find_probes(self, &af.pf);
	if (ret < 0) {
		
		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;
}
static int convert_variable_type(Dwarf_Die *vr_die,
				 struct probe_trace_arg *tvar,
				 const char *cast)
{
	struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
	Dwarf_Die type;
	char buf[16];
	int bsize, boffs, total;
	int ret;

	
	if (cast && strcmp(cast, "string") != 0) {
		
		tvar->type = strdup(cast);
		return (tvar->type == NULL) ? -ENOMEM : 0;
	}

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

	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;
	}

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

	if (cast && strcmp(cast, "string") == 0) {	
		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.\n",
				   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.\n");
				return -ENOENT;
			}
			while (*ref_ptr)
				ref_ptr = &(*ref_ptr)->next;
			
			*ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
			if (*ref_ptr == NULL) {
				pr_warning("Out of memory error\n");
				return -ENOMEM;
			}
		}
		if (!die_compare_name(&type, "char") &&
		    !die_compare_name(&type, "unsigned char")) {
			pr_warning("Failed to cast into string: "
				   "%s is not (unsigned) char *.\n",
				   dwarf_diename(vr_die));
			return -EINVAL;
		}
		tvar->type = strdup(cast);
		return (tvar->type == NULL) ? -ENOMEM : 0;
	}

	ret = dwarf_bytesize(&type);
	if (ret <= 0)
		
		return 0;
	ret = BYTES_TO_BITS(ret);

	
	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;
	}
	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;
	return 0;
}
Пример #10
0
static int find_probe_point_by_func(struct probe_finder *pf)
{
	struct dwarf_callback_param _param = {.data = (void *)pf,
					      .retval = 0};
	dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
	return _param.retval;
}

struct pubname_callback_param {
	char *function;
	char *file;
	Dwarf_Die *cu_die;
	Dwarf_Die *sp_die;
	int found;
};

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

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

		if (die_compare_name(param->sp_die, param->function)) {
			if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
				return DWARF_CB_OK;

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

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

	return DWARF_CB_OK;
}

/* Find probe points from debuginfo */
static int debuginfo__find_probes(struct debuginfo *dbg,
				  struct probe_finder *pf)
{
	struct perf_probe_point *pp = &pf->pev->point;
	Dwarf_Off off, noff;
	size_t cuhl;
	Dwarf_Die *diep;
	int ret = 0;

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

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

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

	if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
	    shdr.sh_type == SHT_PROGBITS) {
		pf->cfi = dwarf_getcfi_elf(elf);
	} else {
		pf->cfi = dwarf_getcfi(dbg->dbg);
	}
#endif

	off = 0;
	pf->lcache = intlist__new(NULL);
	if (!pf->lcache)
		return -ENOMEM;

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

		dwarf_getpubnames(dbg->dbg, pubname_search_cb,
				  &pubname_param, 0);
		if (pubname_param.found) {
			ret = probe_point_search_cb(&pf->sp_die, &probe_param);
			if (ret)
				goto found;
		}
	}

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

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

		if (!pp->file || pf->fname) {
			if (pp->function)
				ret = find_probe_point_by_func(pf);
			else if (pp->lazy_line)
				ret = find_probe_point_lazy(&pf->cu_die, pf);
			else {
				pf->lno = pp->line;
				ret = find_probe_point_by_line(pf);
			}
			if (ret < 0)
				break;
		}
		off = noff;
	}

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

	return ret;
}

struct local_vars_finder {
	struct probe_finder *pf;
	struct perf_probe_arg *args;
	int max_args;
	int nargs;
	int ret;
};

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

	tag = dwarf_tag(die_mem);
	if (tag == DW_TAG_formal_parameter ||
	    tag == DW_TAG_variable) {
		if (convert_variable_location(die_mem, vf->pf->addr,
					      vf->pf->fb_ops, &pf->sp_die,
					      NULL) == 0) {
			vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
			if (vf->args[vf->nargs].var == NULL) {
				vf->ret = -ENOMEM;
				return DIE_FIND_CB_END;
			}
			pr_debug(" %s", vf->args[vf->nargs].var);
			vf->nargs++;
		}
	}

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

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

	for (i = 0; i < pf->pev->nargs; i++) {
		/* var never be NULL */
		if (strcmp(pf->pev->args[i].var, "$vars") == 0) {
			pr_debug("Expanding $vars into:");
			vf.nargs = n;
			/* Special local variables */
			die_find_child(sc_die, copy_variables_cb, (void *)&vf,
				       &die_mem);
			pr_debug(" (%d)\n", vf.nargs - n);
			if (vf.ret < 0)
				return vf.ret;
			n = vf.nargs;
		} else {
			/* Copy normal argument */
			args[n] = pf->pev->args[i];
			n++;
		}
	}
	return n;
}

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

	/* Trace point should be converted from subprogram DIE */
	ret = convert_to_trace_point(&pf->sp_die, tf->mod, 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);

	/* Expand special probe argument if exist */
	args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
	if (args == NULL)
		return -ENOMEM;

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

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

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

end:
	free(args);
	return ret;
}

/* Find probe_trace_events specified by perf_probe_event from debuginfo */
int debuginfo__find_trace_events(struct debuginfo *dbg,
				 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},
			.mod = dbg->mod, .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 = debuginfo__find_probes(dbg, &tf.pf);
	if (ret < 0) {
		zfree(tevs);
		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, &af->pf.sp_die,
						NULL);
		if (ret == 0) {
			ret = die_get_varname(die_mem, buf, MAX_VAR_LEN);
			pr_debug2("Add new var: %s\n", buf);
			if (ret > 0)
				strlist__add(vl->vars, buf);
		}
	}

	if (af->child && dwarf_haspc(die_mem, af->pf.addr))
		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 *sc_die, struct probe_finder *pf)
{
	struct available_var_finder *af =
			container_of(pf, struct available_var_finder, pf);
	struct variable_list *vl;
	Dwarf_Die die_mem;
	int ret;

	/* 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++];

	/* Trace point should be converted from subprogram DIE */
	ret = convert_to_trace_point(&pf->sp_die, af->mod, 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;
	af->child = true;
	die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);

	/* Find external variables */
	if (!af->externs)
		goto out;
	/* Don't need to search child DIE for externs. */
	af->child = false;
	die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);

out:
	if (strlist__empty(vl->vars)) {
		strlist__delete(vl->vars);
		vl->vars = NULL;
	}

	return ret;
}

/*
 * Find available variables at given probe point
 * Return the number of found probe points. Return 0 if there is no
 * matched probe point. Return <0 if an error occurs.
 */
int debuginfo__find_available_vars_at(struct debuginfo *dbg,
				      struct perf_probe_event *pev,
				      struct variable_list **vls,
				      int max_vls, bool externs)
{
	struct available_var_finder af = {
			.pf = {.pev = pev, .callback = add_available_vars},
			.mod = dbg->mod,
			.max_vls = max_vls, .externs = externs};
	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 = debuginfo__find_probes(dbg, &af.pf);
	if (ret < 0) {
		/* Free vlist for error */
		while (af.nvls--) {
			zfree(&af.vls[af.nvls].point.symbol);
			strlist__delete(af.vls[af.nvls].vars);
		}
		zfree(vls);
		return ret;
	}

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

/* Reverse search */
int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
				struct perf_probe_point *ppt)
{
	Dwarf_Die cudie, spdie, indie;
	Dwarf_Addr _addr = 0, baseaddr = 0;
	const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
	int baseline = 0, lineno = 0, ret = 0;

	/* Find cu die */
	if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
		pr_warning("Failed to find debug information for address %lx\n",
			   addr);
		ret = -EINVAL;
		goto end;
	}

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

	/* Find a corresponding function (name, baseline and baseaddr) */
	if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
		/* Get function entry information */
		func = basefunc = dwarf_diename(&spdie);
		if (!func ||
		    dwarf_entrypc(&spdie, &baseaddr) != 0 ||
		    dwarf_decl_line(&spdie, &baseline) != 0) {
			lineno = 0;
			goto post;
		}

		fname = dwarf_decl_file(&spdie);
		if (addr == (unsigned long)baseaddr) {
			/* Function entry - Relative line number is 0 */
			lineno = baseline;
			goto post;
		}

		/* Track down the inline functions step by step */
		while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
						&indie)) {
			/* There is an inline function */
			if (dwarf_entrypc(&indie, &_addr) == 0 &&
			    _addr == addr) {
				/*
				 * addr is at an inline function entry.
				 * In this case, lineno should be the call-site
				 * line number. (overwrite lineinfo)
				 */
				lineno = die_get_call_lineno(&indie);
				fname = die_get_call_file(&indie);
				break;
			} else {
				/*
				 * addr is in an inline function body.
				 * Since lineno points one of the lines
				 * of the inline function, baseline should
				 * be the entry line of the inline function.
				 */
				tmp = dwarf_diename(&indie);
				if (!tmp ||
				    dwarf_decl_line(&indie, &baseline) != 0)
					break;
				func = tmp;
				spdie = indie;
			}
		}
		/* Verify the lineno and baseline are in a same file */
		tmp = dwarf_decl_file(&spdie);
		if (!tmp || strcmp(tmp, fname) != 0)
			lineno = 0;
	}

post:
	/* Make a relative line number or an offset */
	if (lineno)
		ppt->line = lineno - baseline;
	else if (basefunc) {
		ppt->offset = addr - (unsigned long)baseaddr;
		func = basefunc;
	}

	/* Duplicate strings */
	if (func) {
		ppt->function = strdup(func);
		if (ppt->function == NULL) {
			ret = -ENOMEM;
			goto end;
		}
	}
	if (fname) {
		ppt->file = strdup(fname);
		if (ppt->file == NULL) {
			zfree(&ppt->function);
			ret = -ENOMEM;
			goto end;
		}
	}
end:
	if (ret == 0 && (fname || func))
		ret = 1;	/* Found a point */
	return ret;
}

/* Add a line and store the src path */
static int line_range_add_line(const char *src, unsigned int lineno,
			       struct line_range *lr)
{
	/* Copy source path */
	if (!lr->path) {
		lr->path = strdup(src);
		if (lr->path == NULL)
			return -ENOMEM;
	}
	return intlist__add(lr->line_list, lineno);
}

static int line_range_walk_cb(const char *fname, int lineno,
			      Dwarf_Addr addr __maybe_unused,
			      void *data)
{
	struct line_finder *lf = data;
	int err;

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

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

	return 0;
}

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

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

	/* Update status */
	if (ret >= 0)
		if (!intlist__empty(lf->lr->line_list))
			ret = lf->found = 1;
		else
			ret = 0;	/* Lines are not found */
	else {
		zfree(&lf->lr->path);
	}
	return ret;
}
Пример #11
0
/**
 * die_walk_instances - Walk on instances of given DIE
 * @or_die: an abstract original DIE
 * @callback: a callback function which is called with instance DIE
 * @data: user data
 *
 * Walk on the instances of give @in_die. @in_die must be an inlined function
 * declartion. This returns the return value of @callback if it returns
 * non-zero value, or -ENOENT if there is no instance.
 */
int die_walk_instances(Dwarf_Die *or_die, int (*callback)(Dwarf_Die *, void *),
		       void *data)
{
	Dwarf_Die cu_die;
	Dwarf_Die die_mem;
	struct __instance_walk_param iwp = {
		.addr = or_die->addr,
		.callback = callback,
		.data = data,
		.retval = -ENOENT,
	};

	if (dwarf_diecu(or_die, &cu_die, NULL, NULL) == NULL)
		return -ENOENT;

	die_find_child(&cu_die, __die_walk_instances_cb, &iwp, &die_mem);

	return iwp.retval;
}

/* Line walker internal parameters */
struct __line_walk_param {
	bool recursive;
	line_walk_callback_t callback;
	void *data;
	int retval;
};

static int __die_walk_funclines_cb(Dwarf_Die *in_die, void *data)
{
	struct __line_walk_param *lw = data;
	Dwarf_Addr addr = 0;
	const char *fname;
	int lineno;

	if (dwarf_tag(in_die) == DW_TAG_inlined_subroutine) {
		fname = die_get_call_file(in_die);
		lineno = die_get_call_lineno(in_die);
		if (fname && lineno > 0 && dwarf_entrypc(in_die, &addr) == 0) {
			lw->retval = lw->callback(fname, lineno, addr, lw->data);
			if (lw->retval != 0)
				return DIE_FIND_CB_END;
		}
	}
	if (!lw->recursive)
		/* Don't need to search recursively */
		return DIE_FIND_CB_SIBLING;

	if (addr) {
		fname = dwarf_decl_file(in_die);
		if (fname && dwarf_decl_line(in_die, &lineno) == 0) {
			lw->retval = lw->callback(fname, lineno, addr, lw->data);
			if (lw->retval != 0)
				return DIE_FIND_CB_END;
		}
	}

	/* Continue to search nested inlined function call-sites */
	return DIE_FIND_CB_CONTINUE;
}

/* Walk on lines of blocks included in given DIE */
static int __die_walk_funclines(Dwarf_Die *sp_die, bool recursive,
				line_walk_callback_t callback, void *data)
{
	struct __line_walk_param lw = {
		.recursive = recursive,
		.callback = callback,
		.data = data,
		.retval = 0,
	};
	Dwarf_Die die_mem;
	Dwarf_Addr addr;
	const char *fname;
	int lineno;

	/* Handle function declaration line */
	fname = dwarf_decl_file(sp_die);
	if (fname && dwarf_decl_line(sp_die, &lineno) == 0 &&
	    dwarf_entrypc(sp_die, &addr) == 0) {
		lw.retval = callback(fname, lineno, addr, data);
		if (lw.retval != 0)
			goto done;
	}
	die_find_child(sp_die, __die_walk_funclines_cb, &lw, &die_mem);
done:
	return lw.retval;
}

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, true, lw->callback, lw->data);
	if (lw->retval != 0)
		return DWARF_CB_ABORT;

	return DWARF_CB_OK;
}

/**
 * die_walk_lines - Walk on lines inside given DIE
 * @rt_die: a root DIE (CU, subprogram or inlined_subroutine)
 * @callback: callback routine
 * @data: user data
 *
 * Walk on all lines inside given @rt_die and call @callback on each line.
 * If the @rt_die is a function, walk only on the lines inside the function,
 * otherwise @rt_die must be a CU DIE.
 * Note that this walks not only dwarf line list, but also function entries
 * and inline call-site.
 */
int die_walk_lines(Dwarf_Die *rt_die, line_walk_callback_t callback, 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(rt_die) != DW_TAG_compile_unit)
		cu_die = dwarf_diecu(rt_die, &die_mem, NULL, NULL);
	else
		cu_die = rt_die;
	if (!cu_die) {
		pr_debug2("Failed to get CU from given DIE.\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 (rt_die != cu_die)
			/*
			 * Address filtering
			 * The line is included in given function, and
			 * no inline block includes it.
			 */
			if (!dwarf_haspc(rt_die, addr) ||
			    die_find_inlinefunc(rt_die, addr, &die_mem))
				continue;
		/* Get source line */
		fname = dwarf_linesrc(line, NULL, NULL);

		ret = callback(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 (rt_die != cu_die)
		/*
		 * Don't need walk functions recursively, because nested
		 * inlined functions don't have lines of the specified DIE.
		 */
		ret = __die_walk_funclines(rt_die, false, callback, data);
	else {
		struct __line_walk_param param = {
			.callback = callback,
			.data = data,
			.retval = 0,
		};
		dwarf_getfuncs(cu_die, __die_walk_culines_cb, &param, 0);
		ret = param.retval;
	}

	return ret;
}

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

static int __die_find_variable_cb(Dwarf_Die *die_mem, void *data)
{
	struct __find_variable_param *fvp = data;
	Dwarf_Attribute attr;
	int tag;

	tag = dwarf_tag(die_mem);
	if ((tag == DW_TAG_formal_parameter ||
	     tag == DW_TAG_variable) &&
	    die_compare_name(die_mem, fvp->name) &&
	/* Does the DIE have location information or external instance? */
	    (dwarf_attr(die_mem, DW_AT_external, &attr) ||
	     dwarf_attr(die_mem, DW_AT_location, &attr)))
		return DIE_FIND_CB_END;
	if (dwarf_haspc(die_mem, fvp->addr))
		return DIE_FIND_CB_CONTINUE;
	else
		return DIE_FIND_CB_SIBLING;
}

/**
 * die_find_variable_at - Find a given name variable at given address
 * @sp_die: a function DIE
 * @name: variable name
 * @addr: address
 * @die_mem: a buffer for result DIE
 *
 * Find a variable DIE called @name at @addr in @sp_die.
 */
Dwarf_Die *die_find_variable_at(Dwarf_Die *sp_die, const char *name,
				Dwarf_Addr addr, Dwarf_Die *die_mem)
{
	struct __find_variable_param fvp = { .name = name, .addr = addr};

	return die_find_child(sp_die, __die_find_variable_cb, (void *)&fvp,
			      die_mem);
}

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

	if (dwarf_tag(die_mem) == DW_TAG_member) {
		if (die_compare_name(die_mem, name))
			return DIE_FIND_CB_END;
		else if (!dwarf_diename(die_mem)) {	/* Unnamed structure */
			Dwarf_Die type_die, tmp_die;
			if (die_get_type(die_mem, &type_die) &&
			    die_find_member(&type_die, name, &tmp_die))
				return DIE_FIND_CB_END;
		}
	}
	return DIE_FIND_CB_SIBLING;
}

/**
 * die_find_member - Find a given name member in a data structure
 * @st_die: a data structure type DIE
 * @name: member name
 * @die_mem: a buffer for result DIE
 *
 * Find a member DIE called @name in @st_die.
 */
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);
}

/**
 * die_get_typename - Get the name of given variable DIE
 * @vr_die: a variable DIE
 * @buf: a buffer for result type name
 * @len: a max-length of @buf
 *
 * Get the name of @vr_die and stores it to @buf. Return the actual length
 * of type name if succeeded. Return -E2BIG if @len is not enough long, and
 * Return -ENOENT if failed to find type name.
 * Note that the result will stores typedef name if possible, and stores
 * "*(function_type)" if the type is a function pointer.
 */
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 ";
		else if (tag == DW_TAG_enumeration_type)
			tmp = "enum ";
		/* 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;
}

/**
 * die_get_varname - Get the name and type of given variable DIE
 * @vr_die: a variable DIE
 * @buf: a buffer for type and variable name
 * @len: the max-length of @buf
 *
 * Get the name and type of @vr_die and stores it in @buf as "type\tname".
 */
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;
}
Пример #12
0
/* Search function from function name */
static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
{
	struct dwarf_callback_param *param = data;
	struct probe_finder *pf = param->data;
	struct perf_probe_point *pp = &pf->pev->point;

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

	pf->fname = dwarf_decl_file(sp_die);
	if (pp->line) { /* Function relative line */
		dwarf_decl_line(sp_die, &pf->lno);
		pf->lno += pp->line;
		param->retval = find_probe_point_by_line(pf);
	} else if (!dwarf_func_inline(sp_die)) {
		/* Real function */
		if (pp->lazy_line)
			param->retval = find_probe_point_lazy(sp_die, pf);
		else {
			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;
			}
			pf->addr += pp->offset;
			/* TODO: Check the address in this function */
			param->retval = convert_probe_point(sp_die, pf);
		}
	} else {
		struct dwarf_callback_param _param = {.data = (void *)pf,
						      .retval = 0};
		/* Inlined function: search instances */
		dwarf_func_inline_instances(sp_die, probe_point_inline_cb,
					    &_param);
		param->retval = _param.retval;
	}

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

static int find_probe_point_by_func(struct probe_finder *pf)
{
	struct dwarf_callback_param _param = {.data = (void *)pf,
					      .retval = 0};
	dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
	return _param.retval;
}

/* Find kprobe_trace_events specified by perf_probe_event from debuginfo */
int find_kprobe_trace_events(int fd, struct perf_probe_event *pev,
			     struct kprobe_trace_event **tevs, int max_tevs)
{
	struct probe_finder pf = {.pev = pev, .max_tevs = max_tevs};
	struct perf_probe_point *pp = &pev->point;
	Dwarf_Off off, noff;
	size_t cuhl;
	Dwarf_Die *diep;
	Dwarf *dbg;
	int ret = 0;

	pf.tevs = zalloc(sizeof(struct kprobe_trace_event) * max_tevs);
	if (pf.tevs == NULL)
		return -ENOMEM;
	*tevs = pf.tevs;
	pf.ntevs = 0;

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

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

	off = 0;
	line_list__init(&pf.lcache);
	/* Loop on CUs (Compilation Unit) */
	while (!dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL) &&
	       ret >= 0) {
		/* Get the DIE(Debugging Information Entry) of this CU */
		diep = dwarf_offdie(dbg, off + cuhl, &pf.cu_die);
		if (!diep)
			continue;

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

		if (!pp->file || pf.fname) {
			if (pp->function)
				ret = find_probe_point_by_func(&pf);
			else if (pp->lazy_line)
				ret = find_probe_point_lazy(NULL, &pf);
			else {
				pf.lno = pp->line;
				ret = find_probe_point_by_line(&pf);
			}
		}
		off = noff;
	}
	line_list__free(&pf.lcache);
	dwarf_end(dbg);

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

/* 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;
	bool found = false;

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

	/* Find cu die */
	if (!dwarf_addrdie(dbg, (Dwarf_Addr)addr, &cudie)) {
		ret = -EINVAL;
		goto end;
	}

	/* Find a corresponding line */
	line = dwarf_getsrc_die(&cudie, (Dwarf_Addr)addr);
	if (line) {
		if (dwarf_lineaddr(line, &laddr) == 0 &&
		    (Dwarf_Addr)addr == laddr &&
		    dwarf_lineno(line, &lineno) == 0) {
			tmp = dwarf_linesrc(line, NULL, NULL);
			if (tmp) {
				ppt->line = lineno;
				ppt->file = strdup(tmp);
				if (ppt->file == NULL) {
					ret = -ENOMEM;
					goto end;
				}
				found = true;
			}
		}
	}

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

		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;
			}
		}
		/* We don't have a line number, let's use offset */
		ppt->offset = addr - (unsigned long)eaddr;
found:
		ppt->function = strdup(tmp);
		if (ppt->function == NULL) {
			ret = -ENOMEM;
			goto end;
		}
		found = true;
	}

end:
	dwarf_end(dbg);
	if (ret >= 0)
		ret = found ? 1 : 0;
	return ret;
}

/* Add a line and store the src path */
static int line_range_add_line(const char *src, unsigned int lineno,
			       struct line_range *lr)
{
	/* Copy real path */
	if (!lr->path) {
		lr->path = strdup(src);
		if (lr->path == NULL)
			return -ENOMEM;
	}
	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);
	if (param->retval < 0)
		return DWARF_CB_ABORT;
	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;
}

/* Find line range from its line number */
static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
{
	Dwarf_Lines *lines;
	Dwarf_Line *line;
	size_t nlines, i;
	Dwarf_Addr addr;
	int lineno, ret = 0;
	const char *src;
	Dwarf_Die die_mem;

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

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

		if (sp_die) {
			/* Address filtering 1: does sp_die include addr? */
			if (dwarf_lineaddr(line, &addr) != 0 ||
			    !dwarf_haspc(sp_die, addr))
				continue;

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

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

		ret = line_range_add_line(src, lineno, lf->lr);
		if (ret < 0)
			return ret;
	}

	/*
	 * 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);

	/* Update status */
	if (ret >= 0)
		if (!list_empty(&lf->lr->line_list))
			ret = lf->found = 1;
		else
			ret = 0;	/* Lines are not found */
	else {
		free(lf->lr->path);
		lf->lr->path = NULL;
	}
	return ret;
}

static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
{
	struct dwarf_callback_param *param = data;

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

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

	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);
		pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
		lf->lno_s = lr->offset + lr->start;
		if (lf->lno_s < 0)	/* Overflow */
			lf->lno_s = INT_MAX;
		lf->lno_e = lr->offset + lr->end;
		if (lf->lno_e < 0)	/* Overflow */
			lf->lno_e = INT_MAX;
		pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
		lr->start = lf->lno_s;
		lr->end = lf->lno_e;
		if (dwarf_func_inline(sp_die)) {
			struct dwarf_callback_param _param;
			_param.data = (void *)lf;
			_param.retval = 0;
			dwarf_func_inline_instances(sp_die,
						    line_range_inline_cb,
						    &_param);
			param->retval = _param.retval;
		} else
			param->retval = find_line_range_by_line(sp_die, lf);
		return DWARF_CB_ABORT;
	}
	return DWARF_CB_OK;
}

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

int find_line_range(int fd, struct line_range *lr)
{
	struct line_finder lf = {.lr = lr, .found = 0};
	int ret = 0;
	Dwarf_Off off = 0, noff;
	size_t cuhl;
	Dwarf_Die *diep;
	Dwarf *dbg;

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

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

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

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

		if (!lr->file || lf.fname) {
			if (lr->function)
				ret = find_line_range_by_func(&lf);
			else {
				lf.lno_s = lr->start;
				lf.lno_e = lr->end;
				ret = find_line_range_by_line(NULL, &lf);
			}
		}
		off = noff;
	}
	pr_debug("path: %lx\n", (unsigned long)lr->path);
	dwarf_end(dbg);

	return (ret < 0) ? ret : lf.found;
}
Пример #13
0
static int convert_variable_type(Dwarf_Die *vr_die,
				 struct probe_trace_arg *tvar,
				 const char *cast)
{
	struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
	Dwarf_Die type;
	char buf[16];
	int ret;

	/* 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;
	}

	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;
	}

	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;
	}

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

	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.\n",
				   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.\n");
				return -ENOENT;
			}
			while (*ref_ptr)
				ref_ptr = &(*ref_ptr)->next;
			/* Add new reference with offset +0 */
			*ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
			if (*ref_ptr == NULL) {
				pr_warning("Out of memory error\n");
				return -ENOMEM;
			}
		}
		if (!die_compare_name(&type, "char") &&
		    !die_compare_name(&type, "unsigned char")) {
			pr_warning("Failed to cast into string: "
				   "%s is not (unsigned) char *.\n",
				   dwarf_diename(vr_die));
			return -EINVAL;
		}
		tvar->type = strdup(cast);
		return (tvar->type == NULL) ? -ENOMEM : 0;
	}

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

	/* 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;
	}
	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;
	return 0;
}
Пример #14
0
/* Walk on lines of blocks included in given DIE */
static int __die_walk_funclines(Dwarf_Die *sp_die,
				line_walk_handler_t handler, void *data)
{
	struct __line_walk_param lw = {
		.handler = handler,
		.data = data,
		.retval = 0,
	};
	Dwarf_Die die_mem;
	Dwarf_Addr addr;
	int lineno;

	/* Handle function declaration line */
	lw.fname = dwarf_decl_file(sp_die);
	if (lw.fname && dwarf_decl_line(sp_die, &lineno) == 0 &&
	    dwarf_entrypc(sp_die, &addr) == 0) {
		lw.retval = handler(lw.fname, lineno, addr, data);
		if (lw.retval != 0)
			goto done;
	}
	die_find_child(sp_die, __die_walk_funclines_cb, &lw, &die_mem);
done:
	return lw.retval;
}

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;
}

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

static int __die_find_variable_cb(Dwarf_Die *die_mem, void *data)
{
	struct __find_variable_param *fvp = data;
	int tag;

	tag = dwarf_tag(die_mem);
	if ((tag == DW_TAG_formal_parameter ||
	     tag == DW_TAG_variable) &&
	    die_compare_name(die_mem, fvp->name))
		return DIE_FIND_CB_FOUND;

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

/* 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)
{
	struct __find_variable_param fvp = { .name = name, .addr = addr};

	return die_find_child(sp_die, __die_find_variable_cb, (void *)&fvp,
			      die_mem);
}

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))
		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);
}

/* 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;
}
Пример #15
0
/* Search function from function name */
static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
{
	struct dwarf_callback_param *param = data;
	struct probe_finder *pf = param->data;
	struct perf_probe_point *pp = &pf->pev->point;

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

	pf->fname = dwarf_decl_file(sp_die);
	if (pp->line) { /* Function relative line */
		dwarf_decl_line(sp_die, &pf->lno);
		pf->lno += pp->line;
		param->retval = find_probe_point_by_line(pf);
	} else if (!dwarf_func_inline(sp_die)) {
		/* Real function */
		if (pp->lazy_line)
			param->retval = find_probe_point_lazy(sp_die, pf);
		else {
			if (dwarf_entrypc(sp_die, &pf->addr) != 0) {
				pr_warning("Failed to get entry address of "
					   "%s.\n", dwarf_diename(sp_die));
				param->retval = -ENOENT;
				return DWARF_CB_ABORT;
			}
			pf->addr += pp->offset;
			/* TODO: Check the address in this function */
			param->retval = call_probe_finder(sp_die, pf);
		}
	} else {
		struct dwarf_callback_param _param = {.data = (void *)pf,
						      .retval = 0};
		/* Inlined function: search instances */
		dwarf_func_inline_instances(sp_die, probe_point_inline_cb,
					    &_param);
		param->retval = _param.retval;
	}

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

static int find_probe_point_by_func(struct probe_finder *pf)
{
	struct dwarf_callback_param _param = {.data = (void *)pf,
					      .retval = 0};
	dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
	return _param.retval;
}

/* Find probe points from debuginfo */
static int find_probes(int fd, struct probe_finder *pf)
{
	struct perf_probe_point *pp = &pf->pev->point;
	Dwarf_Off off, noff;
	size_t cuhl;
	Dwarf_Die *diep;
	Dwarf *dbg = NULL;
	Dwfl *dwfl;
	Dwarf_Addr bias;	/* Currently ignored */
	int ret = 0;

	dbg = dwfl_init_offline_dwarf(fd, &dwfl, &bias);
	if (!dbg) {
		pr_warning("No debug information found in the vmlinux - "
			"please rebuild with CONFIG_DEBUG_INFO=y.\n");
		return -EBADF;
	}

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

	off = 0;
	line_list__init(&pf->lcache);
	/* Loop on CUs (Compilation Unit) */
	while (!dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
		/* Get the DIE(Debugging Information Entry) of this CU */
		diep = dwarf_offdie(dbg, off + cuhl, &pf->cu_die);
		if (!diep)
			continue;

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

		if (!pp->file || pf->fname) {
			if (pp->function)
				ret = find_probe_point_by_func(pf);
			else if (pp->lazy_line)
				ret = find_probe_point_lazy(NULL, pf);
			else {
				pf->lno = pp->line;
				ret = find_probe_point_by_line(pf);
			}
			if (ret < 0)
				break;
		}
		off = noff;
	}
	line_list__free(&pf->lcache);
	if (dwfl)
		dwfl_end(dwfl);

	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);
			pr_debug2("Add new var: %s\n", buf);
			if (ret > 0)
				strlist__add(vl->vars, buf);
		}
	}

	if (af->child && dwarf_haspc(die_mem, af->pf.addr))
		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;
	Dwarf_Die die_mem, *scopes = NULL;
	int ret, nscopes;

	/* 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;
	af->child = true;
	die_find_child(sp_die, collect_variables_cb, (void *)af, &die_mem);

	/* 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:
	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,
			   struct variable_list **vls, int max_vls,
			   bool externs)
{
	struct available_var_finder af = {
			.pf = {.pev = pev, .callback = add_available_vars},
			.max_vls = max_vls, .externs = externs};
	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;
}