- 根目录:
- tools
- perf
- util
- probe-finder.c
/*
* probe-finder.c : C expression to kprobe event converter
*
* Written by Masami Hiramatsu <mhiramat@redhat.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
*/
#include <sys/utsname.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <unistd.h>
#include <getopt.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <dwarf-regs.h>
#include <linux/bitops.h>
#include "event.h"
#include "debug.h"
#include "util.h"
#include "symbol.h"
#include "probe-finder.h"
/* Kprobe tracer basic type is up to u64 */
#define MAX_BASIC_TYPE_BITS 64
/* Line number list operations */
/* Add a line to line number list */
static int line_list__add_line(struct list_head *head, int line)
{
struct line_node *ln;
struct list_head *p;
/* Reverse search, because new line will be the last one */
list_for_each_entry_reverse(ln, head, list) {
if (ln->line < line) {
p = &ln->list;
goto found;
} else if (ln->line == line) /* Already exist */
return 1;
}
/* List is empty, or the smallest entry */
p = head;
found:
pr_debug("line list: add a line %u\n", line);
ln = zalloc(sizeof(struct line_node));
if (ln == NULL)
return -ENOMEM;
ln->line = line;
INIT_LIST_HEAD(&ln->list);
list_add(&ln->list, p);
return 0;
}
/* Check if the line in line number list */
static int line_list__has_line(struct list_head *head, int line)
{
struct line_node *ln;
/* Reverse search, because new line will be the last one */
list_for_each_entry(ln, head, list)
if (ln->line == line)
return 1;
return 0;
}
/* Init line number list */
static void line_list__init(struct list_head *head)
{
INIT_LIST_HEAD(head);
}
/* Free line number list */
static void line_list__free(struct list_head *head)
{
struct line_node *ln;
while (!list_empty(head)) {
ln = list_first_entry(head, struct line_node, list);
list_del(&ln->list);
free(ln);
}
}
/* Dwarf FL wrappers */
static char *debuginfo_path; /* Currently dummy */
static const Dwfl_Callbacks offline_callbacks = {
.find_debuginfo = dwfl_standard_find_debuginfo,
.debuginfo_path = &debuginfo_path,
.section_address = dwfl_offline_section_address,
/* We use this table for core files too. */
.find_elf = dwfl_build_id_find_elf,
};
/* Get a Dwarf from offline image */
static int debuginfo__init_offline_dwarf(struct debuginfo *self,
const char *path)
{
Dwfl_Module *mod;
int fd;
fd = open(path, O_RDONLY);
if (fd < 0)
return fd;
self->dwfl = dwfl_begin(&offline_callbacks);
if (!self->dwfl)
goto error;
mod = dwfl_report_offline(self->dwfl, "", "", fd);
if (!mod)
goto error;
self->dbg = dwfl_module_getdwarf(mod, &self->bias);
if (!self->dbg)
goto error;
return 0;
error:
if (self->dwfl)
dwfl_end(self->dwfl);
else
close(fd);
memset(self, 0, sizeof(*self));
return -ENOENT;
}
#if _ELFUTILS_PREREQ(0, 148)
/* This method is buggy if elfutils is older than 0.148 */
static int __linux_kernel_find_elf(Dwfl_Module *mod,
void **userdata,
const char *module_name,
Dwarf_Addr base,
char **file_name, Elf **elfp)
{
int fd;
const char *path = kernel_get_module_path(module_name);
pr_debug2("Use file %s for %s\n", path, module_name);
if (path) {
fd = open(path, O_RDONLY);
if (fd >= 0) {
*file_name = strdup(path);
return fd;
}
}
/* If failed, try to call standard method */
return dwfl_linux_kernel_find_elf(mod, userdata, module_name, base,
file_name, elfp);
}
static const Dwfl_Callbacks kernel_callbacks = {
.find_debuginfo = dwfl_standard_find_debuginfo,
.debuginfo_path = &debuginfo_path,
.find_elf = __linux_kernel_find_elf,
.section_address = dwfl_linux_kernel_module_section_address,
};
/* Get a Dwarf from live kernel image */
static int debuginfo__init_online_kernel_dwarf(struct debuginfo *self,
Dwarf_Addr addr)
{
self->dwfl = dwfl_begin(&kernel_callbacks);
if (!self->dwfl)
return -EINVAL;
/* Load the kernel dwarves: Don't care the result here */
dwfl_linux_kernel_report_kernel(self->dwfl);
dwfl_linux_kernel_report_modules(self->dwfl);
self->dbg = dwfl_addrdwarf(self->dwfl, addr, &self->bias);
/* Here, check whether we could get a real dwarf */
if (!self->dbg) {
pr_debug("Failed to find kernel dwarf at %lx\n",
(unsigned long)addr);
dwfl_end(self->dwfl);
memset(self, 0, sizeof(*self));
return -ENOENT;
}
return 0;
}
#else
/* With older elfutils, this just support kernel module... */
static int debuginfo__init_online_kernel_dwarf(struct debuginfo *self,
Dwarf_Addr addr __used)
{
const char *path = kernel_get_module_path("kernel");
if (!path) {
pr_err("Failed to find vmlinux path\n");
return -ENOENT;
}
pr_debug2("Use file %s for debuginfo\n", path);
return debuginfo__init_offline_dwarf(self, path);
}
#endif
struct debuginfo *debuginfo__new(const char *path)
{
struct debuginfo *self = zalloc(sizeof(struct debuginfo));
if (!self)
return NULL;
if (debuginfo__init_offline_dwarf(self, path) < 0) {
free(self);
self = NULL;
}
return self;
}
struct debuginfo *debuginfo__new_online_kernel(unsigned long addr)
{
struct debuginfo *self = zalloc(sizeof(struct debuginfo));
if (!self)
return NULL;
if (debuginfo__init_online_kernel_dwarf(self, (Dwarf_Addr)addr) < 0) {
free(self);
self = NULL;
}
return self;
}
void debuginfo__delete(struct debuginfo *self)
{
if (self) {
if (self->dwfl)
dwfl_end(self->dwfl);
free(self);
}
}
/*
* Probe finder related functions
*/
static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
{
struct probe_trace_arg_ref *ref;
ref = zalloc(sizeof(struct probe_trace_arg_ref));
if (ref != NULL)
ref->offset = offs;
return ref;
}
/*
* Convert a location into trace_arg.
* If tvar == NULL, this just checks variable can be converted.
*/
static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
Dwarf_Op *fb_ops,
struct probe_trace_arg *tvar)
{
Dwarf_Attribute attr;
Dwarf_Op *op;
size_t nops;
unsigned int regn;
Dwarf_Word offs = 0;
bool ref = false;
const char *regs;
int ret;
if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
goto static_var;
/* TODO: handle more than 1 exprs */
if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL ||
dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0 ||
nops == 0) {
/* TODO: Support const_value */
return -ENOENT;
}
if (op->atom == DW_OP_addr) {
static_var:
if (!tvar)
return 0;
/* Static variables on memory (not stack), make @varname */
ret = strlen(dwarf_diename(vr_die));
tvar->value = zalloc(ret + 2);
if (tvar->value == NULL)
return -ENOMEM;
snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
tvar->ref = alloc_trace_arg_ref((long)offs);
if (tvar->ref == NULL)
return -ENOMEM;
return 0;
}
/* If this is based on frame buffer, set the offset */
if (op->atom == DW_OP_fbreg) {
if (fb_ops == NULL)
return -ENOTSUP;
ref = true;
offs = op->number;
op = &fb_ops[0];
}
if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
regn = op->atom - DW_OP_breg0;
offs += op->number;
ref = true;
} else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
regn = op->atom - DW_OP_reg0;
} else if (op->atom == DW_OP_bregx) {
regn = op->number;
offs += op->number2;
ref = true;
} else if (op->atom == DW_OP_regx) {
regn = op->number;
} else {
pr_debug("DW_OP %x is not supported.\n", op->atom);
return -ENOTSUP;
}
if (!tvar)
return 0;
regs = get_arch_regstr(regn);
if (!regs) {
/* This should be a bug in DWARF or this tool */
pr_warning("Mapping for the register number %u "
"missing on this architecture.\n", regn);
return -ERANGE;
}
tvar->value = strdup(regs);
if (tvar->value == NULL)
return -ENOMEM;
if (ref) {
tvar->ref = alloc_trace_arg_ref((long)offs);
if (tvar->ref == NULL)
return -ENOMEM;
}
return 0;
}
#define BYTES_TO_BITS(nb) ((nb) * BITS_PER_LONG / sizeof(long))
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;
/* 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;
}
bsize = dwarf_bitsize(vr_die);
if (bsize > 0) {
/* This is a bitfield */
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) { /* 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 = dwarf_bytesize(&type);
if (ret <= 0)
/* No size ... try to use default type */
return 0;
ret = BYTES_TO_BITS(ret);
/* 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;
}
static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
struct perf_probe_arg_field *field,
struct probe_trace_arg_ref **ref_ptr,
Dwarf_Die *die_mem)
{
struct probe_trace_arg_ref *ref = *ref_ptr;
Dwarf_Die type;
Dwarf_Word offs;
int ret, tag;
pr_debug("converting %s in %s\n", field->name, varname);
if (die_get_real_type(vr_die, &type) == NULL) {
pr_warning("Failed to get the type of %s.\n", varname);
return -ENOENT;
}
pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
tag = dwarf_tag(&type);
if (field->name[0] == '[' &&
(tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
if (field->next)
/* Save original type for next field */
memcpy(die_mem, &type, sizeof(*die_mem));
/* Get the type of this array */
if (die_get_real_type(&type, &type) == NULL) {
pr_warning("Failed to get the type of %s.\n", varname);
return -ENOENT;
}
pr_debug2("Array real type: (%x)\n",
(unsigned)dwarf_dieoffset(&type));
if (tag == DW_TAG_pointer_type) {
ref = zalloc(sizeof(struct probe_trace_arg_ref));
if (ref == NULL)
return -ENOMEM;
if (*ref_ptr)
(*ref_ptr)->next = ref;
else
*ref_ptr = ref;
}
ref->offset += dwarf_bytesize(&type) * field->index;
if (!field->next)
/* Save vr_die for converting types */
memcpy(die_mem, vr_die, sizeof(*die_mem));
goto next;
} else if (tag == DW_TAG_pointer_type) {
/* Check the pointer and dereference */
if (!field->ref) {
pr_err("Semantic error: %s must be referred by '->'\n",
field->name);
return -EINVAL;
}
/* Get the type pointed by this pointer */
if (die_get_real_type(&type, &type) == NULL) {
pr_warning("Failed to get the type of %s.\n", varname);
return -ENOENT;
}
/* Verify it is a data structure */
if (dwarf_tag(&type) != DW_TAG_structure_type) {
pr_warning("%s is not a data structure.\n", varname);
return -EINVAL;
}
ref = zalloc(sizeof(struct probe_trace_arg_ref));
if (ref == NULL)
return -ENOMEM;
if (*ref_ptr)
(*ref_ptr)->next = ref;
else
*ref_ptr = ref;
} else {
/* Verify it is a data structure */
if (tag != DW_TAG_structure_type) {
pr_warning("%s is not a data structure.\n", varname);
return -EINVAL;
}
if (field->name[0] == '[') {
pr_err("Semantic error: %s is not a pointor"
" nor array.\n", varname);
return -EINVAL;
}
if (field->ref) {
pr_err("Semantic error: %s must be referred by '.'\n",
field->name);
return -EINVAL;
}
if (!ref) {
pr_warning("Structure on a register is not "
"supported yet.\n");
return -ENOTSUP;
}
}
if (die_find_member(&type, field->name, die_mem) == NULL) {
pr_warning("%s(tyep:%s) has no member %s.\n", varname,
dwarf_diename(&type), field->name);
return -EINVAL;
}
/* Get the offset of the field */
ret = die_get_data_member_location(die_mem, &offs);
if (ret < 0) {
pr_warning("Failed to get the offset of %s.\n", field->name);
return ret;
}
ref->offset += (long)offs;
next:
/* Converting next field */
if (field->next)
return convert_variable_fields(die_mem, field->name,
field->next, &ref, die_mem);
else
return 0;
}
/* Show a variables in kprobe event format */
static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
{
Dwarf_Die die_mem;
int ret;
pr_debug("Converting variable %s into trace event.\n",
dwarf_diename(vr_die));
ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
pf->tvar);
if (ret == -ENOENT)
pr_err("Failed to find the location of %s at this address.\n"
" Perhaps, it has been optimized out.\n", pf->pvar->var);
else if (ret == -ENOTSUP)
pr_err("Sorry, we don't support this variable location yet.\n");
else if (pf->pvar->field) {
ret = convert_variable_fields(vr_die, pf->pvar->var,
pf->pvar->field, &pf->tvar->ref,
&die_mem);
vr_die = &die_mem;
}
if (ret == 0)
ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
/* *expr will be cached in libdw. Don't free it. */
return ret;
}
/* Find a variable in a scope DIE */
static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
{
Dwarf_Die vr_die;
char buf[32], *ptr;
int ret = 0;
if (!is_c_varname(pf->pvar->var)) {
/* Copy raw parameters */
pf->tvar->value = strdup(pf->pvar->var);
if (pf->tvar->value == NULL)
return -ENOMEM;
if (pf->pvar->type) {
pf->tvar->type = strdup(pf->pvar->type);
if (pf->tvar->type == NULL)
return -ENOMEM;
}
if (pf->pvar->name) {
pf->tvar->name = strdup(pf->pvar->name);
if (pf->tvar->name == NULL)
return -ENOMEM;
} else
pf->tvar->name = NULL;
return 0;
}
if (pf->pvar->name)
pf->tvar->name = strdup(pf->pvar->name);
else {
ret = synthesize_perf_probe_arg(pf->pvar, buf, 32);
if (ret < 0)
return ret;
ptr = strchr(buf, ':'); /* Change type separator to _ */
if (ptr)
*ptr = '_';
pf->tvar->name = strdup(buf);
}
if (pf->tvar->name == NULL)
return -ENOMEM;
pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
/* Search child die for local variables and parameters. */
if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
/* Search again in global variables */
if (!die_find_variable_at(&pf->cu_die, pf->pvar->var, 0, &vr_die))
ret = -ENOENT;
}
if (ret >= 0)
ret = convert_variable(&vr_die, pf);
if (ret < 0)
pr_warning("Failed to find '%s' in this function.\n",
pf->pvar->var);
return ret;
}
/* Convert subprogram DIE to trace point */
static int convert_to_trace_point(Dwarf_Die *sp_die, Dwarf_Addr paddr,
bool retprobe, struct probe_trace_point *tp)
{
Dwarf_Addr eaddr, highaddr;
const char *name;
/* Copy the name of probe point */
name = dwarf_diename(sp_die);
if (name) {
if (dwarf_entrypc(sp_die, &eaddr) != 0) {
pr_warning("Failed to get entry address of %s\n",
dwarf_diename(sp_die));
return -ENOENT;
}
if (dwarf_highpc(sp_die, &highaddr) != 0) {
pr_warning("Failed to get end address of %s\n",
dwarf_diename(sp_die));
return -ENOENT;
}
if (paddr > highaddr) {
pr_warning("Offset specified is greater than size of %s\n",
dwarf_diename(sp_die));
return -EINVAL;
}
tp->symbol = strdup(name);
if (tp->symbol == NULL)
return -ENOMEM;
tp->offset = (unsigned long)(paddr - eaddr);
} else
/* This function has no name. */
tp->offset = (unsigned long)paddr;
/* Return probe must be on the head of a subprogram */
if (retprobe) {
if (eaddr != paddr) {
pr_warning("Return probe must be on the head of"
" a real function.\n");
return -EINVAL;
}
tp->retprobe = true;
}
return 0;
}
/* Call probe_finder callback with scope DIE */
static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
{
Dwarf_Attribute fb_attr;
size_t nops;
int ret;
if (!sc_die) {
pr_err("Caller must pass a scope DIE. Program error.\n");
return -EINVAL;
}
/* If not a real subprogram, find a real one */
if (dwarf_tag(sc_die) != DW_TAG_subprogram) {
if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
pr_warning("Failed to find probe point in any "
"functions.\n");
return -ENOENT;
}
} else
memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
/* Get the frame base attribute/ops from subprogram */
dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
if (ret <= 0 || nops == 0) {
pf->fb_ops = NULL;
#if _ELFUTILS_PREREQ(0, 142)
} else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
pf->cfi != NULL) {
Dwarf_Frame *frame;
if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
pr_warning("Failed to get call frame on 0x%jx\n",
(uintmax_t)pf->addr);
return -ENOENT;
}
#endif
}
/* Call finder's callback handler */
ret = pf->callback(sc_die, pf);
/* *pf->fb_ops will be cached in libdw. Don't free it. */
pf->fb_ops = NULL;
return ret;
}
struct find_scope_param {
const char *function;
const char *file;
int line;
int diff;
Dwarf_Die *die_mem;
bool found;
};
static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
{
struct find_scope_param *fsp = data;
const char *file;
int lno;
/* Skip if declared file name does not match */
if (fsp->file) {
file = dwarf_decl_file(fn_die);
if (!file || strcmp(fsp->file, file) != 0)
return 0;
}
/* If the function name is given, that's what user expects */
if (fsp->function) {
if (die_compare_name(fn_die, fsp->function)) {
memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
fsp->found = true;
return 1;
}
} else {
/* With the line number, find the nearest declared DIE */
dwarf_decl_line(fn_die, &lno);
if (lno < fsp->line && fsp->diff > fsp->line - lno) {
/* Keep a candidate and continue */
fsp->diff = fsp->line - lno;
memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
fsp->found = true;
}
}
return 0;
}
/* Find an appropriate scope fits to given conditions */
static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
{
struct find_scope_param fsp = {
.function = pf->pev->point.function,
.file = pf->fname,
.line = pf->lno,
.diff = INT_MAX,
.die_mem = die_mem,
.found = false,
};
cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
return fsp.found ? die_mem : NULL;
}
static int probe_point_line_walker(const char *fname, int lineno,
Dwarf_Addr addr, void *data)
{
struct probe_finder *pf = data;
Dwarf_Die *sc_die, die_mem;
int ret;
if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
return 0;
pf->addr = addr;
sc_die = find_best_scope(pf, &die_mem);
if (!sc_die) {
pr_warning("Failed to find scope of probe point.\n");
return -ENOENT;
}
ret = call_probe_finder(sc_die, pf);
/* Continue if no error, because the line will be in inline function */
return ret < 0 ? ret : 0;
}
/* Find probe point from its line number */
static int find_probe_point_by_line(struct probe_finder *pf)
{
return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
}
/* Find lines which match lazy pattern */
static int find_lazy_match_lines(struct list_head *head,
const char *fname, const char *pat)
{
FILE *fp;
char *line = NULL;
size_t line_len;
ssize_t len;
int count = 0, linenum = 1;
fp = fopen(fname, "r");
if (!fp) {
pr_warning("Failed to open %s: %s\n", fname, strerror(errno));
return -errno;
}
while ((len = getline(&line, &line_len, fp)) > 0) {
if (line[len - 1] == '\n')
line[len - 1] = '\0';
if (strlazymatch(line, pat)) {
line_list__add_line(head, linenum);
count++;
}
linenum++;
}
if (ferror(fp))
count = -errno;
free(line);
fclose(fp);
if (count == 0)
pr_debug("No matched lines found in %s.\n", fname);
return count;
}
static int probe_point_lazy_walker(const char *fname, int lineno,
Dwarf_Addr addr, void *data)
{
struct probe_finder *pf = data;
Dwarf_Die *sc_die, die_mem;
int ret;
if (!line_list__has_line(&pf->lcache, lineno) ||
strtailcmp(fname, pf->fname) != 0)
return 0;
pr_debug("Probe line found: line:%d addr:0x%llx\n",
lineno, (unsigned long long)addr);
pf->addr = addr;
pf->lno = lineno;
sc_die = find_best_scope(pf, &die_mem);
if (!sc_die) {
pr_warning("Failed to find scope of probe point.\n");
return -ENOENT;
}
ret = call_probe_finder(sc_die, pf);
/*
* Continue if no error, because the lazy pattern will match
* to other lines
*/
return ret < 0 ? ret : 0;
}
/* Find probe points from lazy pattern */
static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
{
int ret = 0;
if (list_empty(&pf->lcache)) {
/* Matching lazy line pattern */
ret = find_lazy_match_lines(&pf->lcache, pf->fname,
pf->pev->point.lazy_line);
if (ret <= 0)
return ret;
}
return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
}
static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
{
struct probe_finder *pf = data;
struct perf_probe_point *pp = &pf->pev->point;
Dwarf_Addr addr;
int ret;
if (pp->lazy_line)
ret = find_probe_point_lazy(in_die, pf);
else {
/* Get probe address */
if (dwarf_entrypc(in_die, &addr) != 0) {
pr_warning("Failed to get entry address of %s.\n",
dwarf_diename(in_die));
return -ENOENT;
}
pf->addr = addr;
pf->addr += pp->offset;
pr_debug("found inline addr: 0x%jx\n",
(uintmax_t)pf->addr);
ret = call_probe_finder(in_die, pf);
}
return ret;
}
/* Callback parameter with return value for libdw */
struct dwarf_callback_param {
void *data;
int retval;
};
/* 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;
Dwarf_Attribute attr;
/* Check tag and diename */
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;
/* 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;
}
/* Find probe points from debuginfo */
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)
/* Get the call frame information from this dwarf */
pf->cfi = dwarf_getcfi(self->dbg);
#endif
off = 0;
line_list__init(&pf->lcache);
/* 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(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;
}
}
/* Loop on CUs (Compilation Unit) */
while (!dwarf_nextcu(self->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
/* Get the DIE(Debugging Information Entry) of this CU */
diep = dwarf_offdie(self->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;
}
found:
line_list__free(&pf->lcache);
return ret;
}
/* 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;
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, 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];
/* Variable should be found from scope DIE */
ret = find_variable(sc_die, pf);
if (ret != 0)
return ret;
}
return 0;
}
/* Find probe_trace_events specified by perf_probe_event from debuginfo */
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;
/* 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(self, &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 *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, 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 */
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;
/* 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(self, &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;
}
/* Reverse search */
int debuginfo__find_probe_point(struct debuginfo *self, unsigned long addr,
struct perf_probe_point *ppt)
{
Dwarf_Die cudie, spdie, indie;
Dwarf_Addr _addr, baseaddr;
const char *fname = NULL, *func = NULL, *tmp;
int baseline = 0, lineno = 0, ret = 0;
/* Adjust address with bias */
addr += self->bias;
/* Find cu die */
if (!dwarf_addrdie(self->dbg, (Dwarf_Addr)addr - self->bias, &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 */
tmp = dwarf_diename(&spdie);
if (!tmp ||
dwarf_entrypc(&spdie, &baseaddr) != 0 ||
dwarf_decl_line(&spdie, &baseline) != 0)
goto post;
func = tmp;
if (addr == (unsigned long)baseaddr)
/* Function entry - Relative line number is 0 */
lineno = baseline;
else if (die_find_inlinefunc(&spdie, (Dwarf_Addr)addr,
&indie)) {
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.
*/
lineno = die_get_call_lineno(&indie);
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(&spdie, &baseline) == 0)
func = tmp;
}
}
}
post:
/* Make a relative line number or an offset */
if (lineno)
ppt->line = lineno - baseline;
else if (func)
ppt->offset = addr - (unsigned long)baseaddr;
/* 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) {
if (ppt->function) {
free(ppt->function);
ppt->function = NULL;
}
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 line_list__add_line(&lr->line_list, lineno);
}
static int line_range_walk_cb(const char *fname, int lineno,
Dwarf_Addr addr __used,
void *data)
{
struct line_finder *lf = data;
if ((strtailcmp(fname, lf->fname) != 0) ||
(lf->lno_s > lineno || lf->lno_e < lineno))
return 0;
if (line_range_add_line(fname, lineno, lf->lr) < 0)
return -EINVAL;
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 (!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)
{
find_line_range_by_line(in_die, data);
/*
* We have to check all instances of inlined function, because
* some execution paths can be optimized out depends on the
* function argument of instances
*/
return 0;
}
/* 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;
/* Check declared file */
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) /* 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))
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;
}
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, ¶m, 0);
return param.retval;
}
int debuginfo__find_line_range(struct debuginfo *self, 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;
const char *comp_dir;
/* Fastpath: lookup by function name from .debug_pubnames section */
if (lr->function) {
struct pubname_callback_param pubname_param = {
.function = lr->function, .file = lr->file,
.cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
struct dwarf_callback_param line_range_param = {
.data = (void *)&lf, .retval = 0};
dwarf_getpubnames(self->dbg, pubname_search_cb,
&pubname_param, 0);
if (pubname_param.found) {
line_range_search_cb(&lf.sp_die, &line_range_param);
if (lf.found)
goto found;
}
}
/* Loop on CUs (Compilation Unit) */
while (!lf.found && ret >= 0) {
if (dwarf_nextcu(self->dbg, off, &noff, &cuhl,
NULL, NULL, NULL) != 0)
break;
/* Get the DIE(Debugging Information Entry) of this CU */
diep = dwarf_offdie(self->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;
}
found:
/* Store comp_dir */
if (lf.found) {
comp_dir = cu_get_comp_dir(&lf.cu_die);
if (comp_dir) {
lr->comp_dir = strdup(comp_dir);
if (!lr->comp_dir)
ret = -ENOMEM;
}
}
pr_debug("path: %s\n", lr->path);
return (ret < 0) ? ret : lf.found;
}