コード例 #1
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;
}

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;
}
コード例 #2
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;
}
コード例 #3
0
ファイル: probe-finder.c プロジェクト: Abhi1919/ath
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;
}
コード例 #4
0
ファイル: probe-finder.c プロジェクト: LittleForker/linux-2.6
/* 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;
}