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linux-sg2042/tools/perf/util/probe-finder.c

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/*
* probe-finder.c : C expression to kprobe event converter
*
* Written by Masami Hiramatsu <mhiramat@redhat.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
*/
#include <sys/utsname.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <unistd.h>
#include <getopt.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <ctype.h>
#include "event.h"
#include "debug.h"
#include "util.h"
#include "probe-finder.h"
/* Dwarf_Die Linkage to parent Die */
struct die_link {
struct die_link *parent; /* Parent die */
Dwarf_Die die; /* Current die */
};
static Dwarf_Debug __dw_debug;
static Dwarf_Error __dw_error;
/*
* Generic dwarf analysis helpers
*/
#define X86_32_MAX_REGS 8
const char *x86_32_regs_table[X86_32_MAX_REGS] = {
"%ax",
"%cx",
"%dx",
"%bx",
"$stack", /* Stack address instead of %sp */
"%bp",
"%si",
"%di",
};
#define X86_64_MAX_REGS 16
const char *x86_64_regs_table[X86_64_MAX_REGS] = {
"%ax",
"%dx",
"%cx",
"%bx",
"%si",
"%di",
"%bp",
"%sp",
"%r8",
"%r9",
"%r10",
"%r11",
"%r12",
"%r13",
"%r14",
"%r15",
};
/* TODO: switching by dwarf address size */
#ifdef __x86_64__
#define ARCH_MAX_REGS X86_64_MAX_REGS
#define arch_regs_table x86_64_regs_table
#else
#define ARCH_MAX_REGS X86_32_MAX_REGS
#define arch_regs_table x86_32_regs_table
#endif
/* Return architecture dependent register string (for kprobe-tracer) */
static const char *get_arch_regstr(unsigned int n)
{
return (n <= ARCH_MAX_REGS) ? arch_regs_table[n] : NULL;
}
/*
* Compare the tail of two strings.
* Return 0 if whole of either string is same as another's tail part.
*/
static int strtailcmp(const char *s1, const char *s2)
{
int i1 = strlen(s1);
int i2 = strlen(s2);
while (--i1 >= 0 && --i2 >= 0) {
if (s1[i1] != s2[i2])
return s1[i1] - s2[i2];
}
return 0;
}
/* Find the fileno of the target file. */
static Dwarf_Unsigned cu_find_fileno(Dwarf_Die cu_die, const char *fname)
{
Dwarf_Signed cnt, i;
Dwarf_Unsigned found = 0;
char **srcs;
int ret;
if (!fname)
return 0;
ret = dwarf_srcfiles(cu_die, &srcs, &cnt, &__dw_error);
if (ret == DW_DLV_OK) {
for (i = 0; i < cnt && !found; i++) {
if (strtailcmp(srcs[i], fname) == 0)
found = i + 1;
dwarf_dealloc(__dw_debug, srcs[i], DW_DLA_STRING);
}
for (; i < cnt; i++)
dwarf_dealloc(__dw_debug, srcs[i], DW_DLA_STRING);
dwarf_dealloc(__dw_debug, srcs, DW_DLA_LIST);
}
if (found)
pr_debug("found fno: %d\n", (int)found);
return found;
}
/* Compare diename and tname */
static int die_compare_name(Dwarf_Die dw_die, const char *tname)
{
char *name;
int ret;
ret = dwarf_diename(dw_die, &name, &__dw_error);
DIE_IF(ret == DW_DLV_ERROR);
if (ret == DW_DLV_OK) {
ret = strcmp(tname, name);
dwarf_dealloc(__dw_debug, name, DW_DLA_STRING);
} else
ret = -1;
return ret;
}
/* Check the address is in the subprogram(function). */
static int die_within_subprogram(Dwarf_Die sp_die, Dwarf_Addr addr,
Dwarf_Signed *offs)
{
Dwarf_Addr lopc, hipc;
int ret;
/* TODO: check ranges */
ret = dwarf_lowpc(sp_die, &lopc, &__dw_error);
DIE_IF(ret == DW_DLV_ERROR);
if (ret == DW_DLV_NO_ENTRY)
return 0;
ret = dwarf_highpc(sp_die, &hipc, &__dw_error);
DIE_IF(ret != DW_DLV_OK);
if (lopc <= addr && addr < hipc) {
*offs = addr - lopc;
return 1;
} else
return 0;
}
/* Check the die is inlined function */
static Dwarf_Bool die_inlined_subprogram(Dwarf_Die dw_die)
{
/* TODO: check strictly */
Dwarf_Bool inl;
int ret;
ret = dwarf_hasattr(dw_die, DW_AT_inline, &inl, &__dw_error);
DIE_IF(ret == DW_DLV_ERROR);
return inl;
}
/* Get the offset of abstruct_origin */
static Dwarf_Off die_get_abstract_origin(Dwarf_Die dw_die)
{
Dwarf_Attribute attr;
Dwarf_Off cu_offs;
int ret;
ret = dwarf_attr(dw_die, DW_AT_abstract_origin, &attr, &__dw_error);
DIE_IF(ret != DW_DLV_OK);
ret = dwarf_formref(attr, &cu_offs, &__dw_error);
DIE_IF(ret != DW_DLV_OK);
dwarf_dealloc(__dw_debug, attr, DW_DLA_ATTR);
return cu_offs;
}
/* Get entry pc(or low pc, 1st entry of ranges) of the die */
static Dwarf_Addr die_get_entrypc(Dwarf_Die dw_die)
{
Dwarf_Attribute attr;
Dwarf_Addr addr;
Dwarf_Off offs;
Dwarf_Ranges *ranges;
Dwarf_Signed cnt;
int ret;
/* Try to get entry pc */
ret = dwarf_attr(dw_die, DW_AT_entry_pc, &attr, &__dw_error);
DIE_IF(ret == DW_DLV_ERROR);
if (ret == DW_DLV_OK) {
ret = dwarf_formaddr(attr, &addr, &__dw_error);
DIE_IF(ret != DW_DLV_OK);
dwarf_dealloc(__dw_debug, attr, DW_DLA_ATTR);
return addr;
}
/* Try to get low pc */
ret = dwarf_lowpc(dw_die, &addr, &__dw_error);
DIE_IF(ret == DW_DLV_ERROR);
if (ret == DW_DLV_OK)
return addr;
/* Try to get ranges */
ret = dwarf_attr(dw_die, DW_AT_ranges, &attr, &__dw_error);
DIE_IF(ret != DW_DLV_OK);
ret = dwarf_formref(attr, &offs, &__dw_error);
DIE_IF(ret != DW_DLV_OK);
ret = dwarf_get_ranges(__dw_debug, offs, &ranges, &cnt, NULL,
&__dw_error);
DIE_IF(ret != DW_DLV_OK);
addr = ranges[0].dwr_addr1;
dwarf_ranges_dealloc(__dw_debug, ranges, cnt);
return addr;
}
/*
* Search a Die from Die tree.
* Note: cur_link->die should be deallocated in this function.
*/
static int __search_die_tree(struct die_link *cur_link,
int (*die_cb)(struct die_link *, void *),
void *data)
{
Dwarf_Die new_die;
struct die_link new_link;
int ret;
if (!die_cb)
return 0;
/* Check current die */
while (!(ret = die_cb(cur_link, data))) {
/* Check child die */
ret = dwarf_child(cur_link->die, &new_die, &__dw_error);
DIE_IF(ret == DW_DLV_ERROR);
if (ret == DW_DLV_OK) {
new_link.parent = cur_link;
new_link.die = new_die;
ret = __search_die_tree(&new_link, die_cb, data);
if (ret)
break;
}
/* Move to next sibling */
ret = dwarf_siblingof(__dw_debug, cur_link->die, &new_die,
&__dw_error);
DIE_IF(ret == DW_DLV_ERROR);
dwarf_dealloc(__dw_debug, cur_link->die, DW_DLA_DIE);
cur_link->die = new_die;
if (ret == DW_DLV_NO_ENTRY)
return 0;
}
dwarf_dealloc(__dw_debug, cur_link->die, DW_DLA_DIE);
return ret;
}
/* Search a die in its children's die tree */
static int search_die_from_children(Dwarf_Die parent_die,
int (*die_cb)(struct die_link *, void *),
void *data)
{
struct die_link new_link;
int ret;
new_link.parent = NULL;
ret = dwarf_child(parent_die, &new_link.die, &__dw_error);
DIE_IF(ret == DW_DLV_ERROR);
if (ret == DW_DLV_OK)
return __search_die_tree(&new_link, die_cb, data);
else
return 0;
}
/* Find a locdesc corresponding to the address */
static int attr_get_locdesc(Dwarf_Attribute attr, Dwarf_Locdesc *desc,
Dwarf_Addr addr)
{
Dwarf_Signed lcnt;
Dwarf_Locdesc **llbuf;
int ret, i;
ret = dwarf_loclist_n(attr, &llbuf, &lcnt, &__dw_error);
DIE_IF(ret != DW_DLV_OK);
ret = DW_DLV_NO_ENTRY;
for (i = 0; i < lcnt; ++i) {
if (llbuf[i]->ld_lopc <= addr &&
llbuf[i]->ld_hipc > addr) {
memcpy(desc, llbuf[i], sizeof(Dwarf_Locdesc));
desc->ld_s =
malloc(sizeof(Dwarf_Loc) * llbuf[i]->ld_cents);
DIE_IF(desc->ld_s == NULL);
memcpy(desc->ld_s, llbuf[i]->ld_s,
sizeof(Dwarf_Loc) * llbuf[i]->ld_cents);
ret = DW_DLV_OK;
break;
}
dwarf_dealloc(__dw_debug, llbuf[i]->ld_s, DW_DLA_LOC_BLOCK);
dwarf_dealloc(__dw_debug, llbuf[i], DW_DLA_LOCDESC);
}
/* Releasing loop */
for (; i < lcnt; ++i) {
dwarf_dealloc(__dw_debug, llbuf[i]->ld_s, DW_DLA_LOC_BLOCK);
dwarf_dealloc(__dw_debug, llbuf[i], DW_DLA_LOCDESC);
}
dwarf_dealloc(__dw_debug, llbuf, DW_DLA_LIST);
return ret;
}
/* Get decl_file attribute value (file number) */
static Dwarf_Unsigned die_get_decl_file(Dwarf_Die sp_die)
{
Dwarf_Attribute attr;
Dwarf_Unsigned fno;
int ret;
ret = dwarf_attr(sp_die, DW_AT_decl_file, &attr, &__dw_error);
DIE_IF(ret != DW_DLV_OK);
dwarf_formudata(attr, &fno, &__dw_error);
DIE_IF(ret != DW_DLV_OK);
dwarf_dealloc(__dw_debug, attr, DW_DLA_ATTR);
return fno;
}
/* Get decl_line attribute value (line number) */
static Dwarf_Unsigned die_get_decl_line(Dwarf_Die sp_die)
{
Dwarf_Attribute attr;
Dwarf_Unsigned lno;
int ret;
ret = dwarf_attr(sp_die, DW_AT_decl_line, &attr, &__dw_error);
DIE_IF(ret != DW_DLV_OK);
dwarf_formudata(attr, &lno, &__dw_error);
DIE_IF(ret != DW_DLV_OK);
dwarf_dealloc(__dw_debug, attr, DW_DLA_ATTR);
return lno;
}
/*
* Probe finder related functions
*/
/* Show a location */
static void show_location(Dwarf_Loc *loc, struct probe_finder *pf)
{
Dwarf_Small op;
Dwarf_Unsigned regn;
Dwarf_Signed offs;
int deref = 0, ret;
const char *regs;
op = loc->lr_atom;
/* If this is based on frame buffer, set the offset */
if (op == DW_OP_fbreg) {
deref = 1;
offs = (Dwarf_Signed)loc->lr_number;
op = pf->fbloc.ld_s[0].lr_atom;
loc = &pf->fbloc.ld_s[0];
} else
offs = 0;
if (op >= DW_OP_breg0 && op <= DW_OP_breg31) {
regn = op - DW_OP_breg0;
offs += (Dwarf_Signed)loc->lr_number;
deref = 1;
} else if (op >= DW_OP_reg0 && op <= DW_OP_reg31) {
regn = op - DW_OP_reg0;
} else if (op == DW_OP_bregx) {
regn = loc->lr_number;
offs += (Dwarf_Signed)loc->lr_number2;
deref = 1;
} else if (op == DW_OP_regx) {
regn = loc->lr_number;
} else
die("Dwarf_OP %d is not supported.\n", op);
regs = get_arch_regstr(regn);
if (!regs)
die("%lld exceeds max register number.\n", regn);
if (deref)
ret = snprintf(pf->buf, pf->len,
" %s=%+lld(%s)", pf->var, offs, regs);
else
ret = snprintf(pf->buf, pf->len, " %s=%s", pf->var, regs);
DIE_IF(ret < 0);
DIE_IF(ret >= pf->len);
}
/* Show a variables in kprobe event format */
static void show_variable(Dwarf_Die vr_die, struct probe_finder *pf)
{
Dwarf_Attribute attr;
Dwarf_Locdesc ld;
int ret;
ret = dwarf_attr(vr_die, DW_AT_location, &attr, &__dw_error);
if (ret != DW_DLV_OK)
goto error;
ret = attr_get_locdesc(attr, &ld, (pf->addr - pf->cu_base));
if (ret != DW_DLV_OK)
goto error;
/* TODO? */
DIE_IF(ld.ld_cents != 1);
show_location(&ld.ld_s[0], pf);
free(ld.ld_s);
dwarf_dealloc(__dw_debug, attr, DW_DLA_ATTR);
return ;
error:
die("Failed to find the location of %s at this address.\n"
" Perhaps, it has been optimized out.\n", pf->var);
}
static int variable_callback(struct die_link *dlink, void *data)
{
struct probe_finder *pf = (struct probe_finder *)data;
Dwarf_Half tag;
int ret;
ret = dwarf_tag(dlink->die, &tag, &__dw_error);
DIE_IF(ret == DW_DLV_ERROR);
if ((tag == DW_TAG_formal_parameter ||
tag == DW_TAG_variable) &&
(die_compare_name(dlink->die, pf->var) == 0)) {
show_variable(dlink->die, pf);
return 1;
}
/* TODO: Support struct members and arrays */
return 0;
}
/* Find a variable in a subprogram die */
static void find_variable(Dwarf_Die sp_die, struct probe_finder *pf)
{
int ret;
if (!is_c_varname(pf->var)) {
/* Output raw parameters */
ret = snprintf(pf->buf, pf->len, " %s", pf->var);
DIE_IF(ret < 0);
DIE_IF(ret >= pf->len);
return ;
}
pr_debug("Searching '%s' variable in context.\n", pf->var);
/* Search child die for local variables and parameters. */
ret = search_die_from_children(sp_die, variable_callback, pf);
if (!ret)
die("Failed to find '%s' in this function.\n", pf->var);
}
/* Get a frame base on the address */
static void get_current_frame_base(Dwarf_Die sp_die, struct probe_finder *pf)
{
Dwarf_Attribute attr;
int ret;
ret = dwarf_attr(sp_die, DW_AT_frame_base, &attr, &__dw_error);
DIE_IF(ret != DW_DLV_OK);
ret = attr_get_locdesc(attr, &pf->fbloc, (pf->addr - pf->cu_base));
DIE_IF(ret != DW_DLV_OK);
dwarf_dealloc(__dw_debug, attr, DW_DLA_ATTR);
}
static void free_current_frame_base(struct probe_finder *pf)
{
free(pf->fbloc.ld_s);
memset(&pf->fbloc, 0, sizeof(Dwarf_Locdesc));
}
/* Show a probe point to output buffer */
static void show_probepoint(Dwarf_Die sp_die, Dwarf_Signed offs,
struct probe_finder *pf)
{
struct probe_point *pp = pf->pp;
char *name;
char tmp[MAX_PROBE_BUFFER];
int ret, i, len;
/* Output name of probe point */
ret = dwarf_diename(sp_die, &name, &__dw_error);
DIE_IF(ret == DW_DLV_ERROR);
if (ret == DW_DLV_OK) {
ret = snprintf(tmp, MAX_PROBE_BUFFER, "%s+%u", name,
(unsigned int)offs);
/* Copy the function name if possible */
if (!pp->function) {
pp->function = strdup(name);
pp->offset = offs;
}
dwarf_dealloc(__dw_debug, name, DW_DLA_STRING);
} else {
/* This function has no name. */
ret = snprintf(tmp, MAX_PROBE_BUFFER, "0x%llx", pf->addr);
if (!pp->function) {
/* TODO: Use _stext */
pp->function = strdup("");
pp->offset = (int)pf->addr;
}
}
DIE_IF(ret < 0);
DIE_IF(ret >= MAX_PROBE_BUFFER);
len = ret;
pr_debug("Probe point found: %s\n", tmp);
/* Find each argument */
get_current_frame_base(sp_die, pf);
for (i = 0; i < pp->nr_args; i++) {
pf->var = pp->args[i];
pf->buf = &tmp[len];
pf->len = MAX_PROBE_BUFFER - len;
find_variable(sp_die, pf);
len += strlen(pf->buf);
}
free_current_frame_base(pf);
pp->probes[pp->found] = strdup(tmp);
pp->found++;
}
static int probeaddr_callback(struct die_link *dlink, void *data)
{
struct probe_finder *pf = (struct probe_finder *)data;
Dwarf_Half tag;
Dwarf_Signed offs;
int ret;
ret = dwarf_tag(dlink->die, &tag, &__dw_error);
DIE_IF(ret == DW_DLV_ERROR);
/* Check the address is in this subprogram */
if (tag == DW_TAG_subprogram &&
die_within_subprogram(dlink->die, pf->addr, &offs)) {
show_probepoint(dlink->die, offs, pf);
return 1;
}
return 0;
}
/* Find probe point from its line number */
static void find_by_line(struct probe_finder *pf)
{
Dwarf_Signed cnt, i, clm;
Dwarf_Line *lines;
Dwarf_Unsigned lineno = 0;
Dwarf_Addr addr;
Dwarf_Unsigned fno;
int ret;
ret = dwarf_srclines(pf->cu_die, &lines, &cnt, &__dw_error);
DIE_IF(ret != DW_DLV_OK);
for (i = 0; i < cnt; i++) {
ret = dwarf_line_srcfileno(lines[i], &fno, &__dw_error);
DIE_IF(ret != DW_DLV_OK);
if (fno != pf->fno)
continue;
ret = dwarf_lineno(lines[i], &lineno, &__dw_error);
DIE_IF(ret != DW_DLV_OK);
if (lineno != pf->lno)
continue;
ret = dwarf_lineoff(lines[i], &clm, &__dw_error);
DIE_IF(ret != DW_DLV_OK);
ret = dwarf_lineaddr(lines[i], &addr, &__dw_error);
DIE_IF(ret != DW_DLV_OK);
pr_debug("Probe line found: line[%d]:%u,%d addr:0x%llx\n",
(int)i, (unsigned)lineno, (int)clm, addr);
pf->addr = addr;
/* Search a real subprogram including this line, */
ret = search_die_from_children(pf->cu_die,
probeaddr_callback, pf);
if (ret == 0)
die("Probe point is not found in subprograms.\n");
/* Continuing, because target line might be inlined. */
}
dwarf_srclines_dealloc(__dw_debug, lines, cnt);
}
/* Search function from function name */
static int probefunc_callback(struct die_link *dlink, void *data)
{
struct probe_finder *pf = (struct probe_finder *)data;
struct probe_point *pp = pf->pp;
struct die_link *lk;
Dwarf_Signed offs;
Dwarf_Half tag;
int ret;
ret = dwarf_tag(dlink->die, &tag, &__dw_error);
DIE_IF(ret == DW_DLV_ERROR);
if (tag == DW_TAG_subprogram) {
if (die_compare_name(dlink->die, pp->function) == 0) {
if (pp->line) { /* Function relative line */
pf->fno = die_get_decl_file(dlink->die);
pf->lno = die_get_decl_line(dlink->die)
+ pp->line;
find_by_line(pf);
return 1;
}
if (die_inlined_subprogram(dlink->die)) {
/* Inlined function, save it. */
ret = dwarf_die_CU_offset(dlink->die,
&pf->inl_offs,
&__dw_error);
DIE_IF(ret != DW_DLV_OK);
pr_debug("inline definition offset %lld\n",
pf->inl_offs);
return 0; /* Continue to search */
}
/* Get probe address */
pf->addr = die_get_entrypc(dlink->die);
pf->addr += pp->offset;
/* TODO: Check the address in this function */
show_probepoint(dlink->die, pp->offset, pf);
return 1; /* Exit; no same symbol in this CU. */
}
} else if (tag == DW_TAG_inlined_subroutine && pf->inl_offs) {
if (die_get_abstract_origin(dlink->die) == pf->inl_offs) {
/* Get probe address */
pf->addr = die_get_entrypc(dlink->die);
pf->addr += pp->offset;
pr_debug("found inline addr: 0x%llx\n", pf->addr);
/* Inlined function. Get a real subprogram */
for (lk = dlink->parent; lk != NULL; lk = lk->parent) {
tag = 0;
dwarf_tag(lk->die, &tag, &__dw_error);
DIE_IF(ret == DW_DLV_ERROR);
if (tag == DW_TAG_subprogram &&
!die_inlined_subprogram(lk->die))
goto found;
}
die("Failed to find real subprogram.\n");
found:
/* Get offset from subprogram */
ret = die_within_subprogram(lk->die, pf->addr, &offs);
DIE_IF(!ret);
show_probepoint(lk->die, offs, pf);
/* Continue to search */
}
}
return 0;
}
static void find_by_func(struct probe_finder *pf)
{
search_die_from_children(pf->cu_die, probefunc_callback, pf);
}
/* Find a probe point */
int find_probepoint(int fd, struct probe_point *pp)
{
Dwarf_Half addr_size = 0;
Dwarf_Unsigned next_cuh = 0;
int cu_number = 0, ret;
struct probe_finder pf = {.pp = pp};
ret = dwarf_init(fd, DW_DLC_READ, 0, 0, &__dw_debug, &__dw_error);
if (ret != DW_DLV_OK)
return -ENOENT;
pp->found = 0;
while (++cu_number) {
/* Search CU (Compilation Unit) */
ret = dwarf_next_cu_header(__dw_debug, NULL, NULL, NULL,
&addr_size, &next_cuh, &__dw_error);
DIE_IF(ret == DW_DLV_ERROR);
if (ret == DW_DLV_NO_ENTRY)
break;
/* Get the DIE(Debugging Information Entry) of this CU */
ret = dwarf_siblingof(__dw_debug, 0, &pf.cu_die, &__dw_error);
DIE_IF(ret != DW_DLV_OK);
/* Check if target file is included. */
if (pp->file)
pf.fno = cu_find_fileno(pf.cu_die, pp->file);
if (!pp->file || pf.fno) {
/* Save CU base address (for frame_base) */
ret = dwarf_lowpc(pf.cu_die, &pf.cu_base, &__dw_error);
DIE_IF(ret == DW_DLV_ERROR);
if (ret == DW_DLV_NO_ENTRY)
pf.cu_base = 0;
if (pp->function)
find_by_func(&pf);
else {
pf.lno = pp->line;
find_by_line(&pf);
}
}
dwarf_dealloc(__dw_debug, pf.cu_die, DW_DLA_DIE);
}
ret = dwarf_finish(__dw_debug, &__dw_error);
DIE_IF(ret != DW_DLV_OK);
return pp->found;
}
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