static int
die_string(dwarf_t *dw, Dwarf_Die die, Dwarf_Half name, char **strp, int req)
{
const char *str = NULL;
if (dwarf_attrval_string(die, name, &str, &dw->dw_err) != DWARF_E_NONE ||
str == NULL) {
if (req)
terminate("die %llu: failed to get string: %s\n",
die_off(dw, die), dwarf_errmsg(&dw->dw_err));
else
*strp = NULL;
return (0);
} else
*strp = xstrdup(str);
return (1);
}
/**
* Finds a function name in DWARF DIE (Debug Information Entry).
* For more info on DWARF format, see http://www.dwarfstd.org/Download.php , http://www.ibm.com/developerworks/library/os-debugging/
*
* @return true if we need to stop search (i.e. either found it or some error happened)
*/
bool FindFunctionNameInDIE(Dwarf_Debug DebugInfo, Dwarf_Die Die, Dwarf_Addr Addr, const char **OutFuncName)
{
Dwarf_Error ErrorInfo;
Dwarf_Half Tag;
Dwarf_Unsigned LowerPC, HigherPC;
char *TempFuncName;
int ReturnCode;
if (dwarf_tag(Die, &Tag, &ErrorInfo) != DW_DLV_OK || Tag != DW_TAG_subprogram ||
dwarf_attrval_unsigned(Die, DW_AT_low_pc, &LowerPC, &ErrorInfo) != DW_DLV_OK ||
dwarf_attrval_unsigned(Die, DW_AT_high_pc, &HigherPC, &ErrorInfo) != DW_DLV_OK ||
Addr < LowerPC || HigherPC <= Addr
)
{
return false;
}
// found it
*OutFuncName = NULL;
Dwarf_Attribute SubAt;
ReturnCode = dwarf_attr(Die, DW_AT_name, &SubAt, &ErrorInfo);
if (ReturnCode == DW_DLV_ERROR)
{
return true; // error, but stop the search
}
else if (ReturnCode == DW_DLV_OK)
{
if (dwarf_formstring(SubAt, &TempFuncName, &ErrorInfo))
{
*OutFuncName = NULL;
}
else
{
*OutFuncName = TempFuncName;
}
return true;
}
// DW_AT_Name is not present, look in DW_AT_specification
Dwarf_Attribute SpecAt;
if (dwarf_attr(Die, DW_AT_specification, &SpecAt, &ErrorInfo))
{
// not found, tough luck
return false;
}
Dwarf_Off Offset;
if (dwarf_global_formref(SpecAt, &Offset, &ErrorInfo))
{
return false;
}
Dwarf_Die SpecDie;
if (dwarf_offdie(DebugInfo, Offset, &SpecDie, &ErrorInfo))
{
return false;
}
if (dwarf_attrval_string(SpecDie, DW_AT_name, OutFuncName, &ErrorInfo))
{
*OutFuncName = NULL;
}
return true;
}
static void
search_func(Dwarf_Debug dbg, Dwarf_Die die, Dwarf_Addr addr, char **rlt_func)
{
Dwarf_Die ret_die, spec_die;
Dwarf_Error de;
Dwarf_Half tag;
Dwarf_Unsigned lopc, hipc;
Dwarf_Off ref;
Dwarf_Attribute sub_at, spec_at;
char *func0;
const char *func1;
int ret;
if (*rlt_func != NULL)
goto done;
if (dwarf_tag(die, &tag, &de)) {
warnx("dwarf_tag: %s", dwarf_errmsg(de));
goto cont_search;
}
if (tag == DW_TAG_subprogram) {
if (dwarf_attrval_unsigned(die, DW_AT_low_pc, &lopc, &de) ||
dwarf_attrval_unsigned(die, DW_AT_high_pc, &hipc, &de))
goto cont_search;
if (handle_high_pc(die, lopc, &hipc) != DW_DLV_OK)
goto cont_search;
if (addr < lopc || addr >= hipc)
goto cont_search;
/* Found it! */
if ((*rlt_func = strdup(unknown)) == NULL)
err(EXIT_FAILURE, "strdup");
ret = dwarf_attr(die, DW_AT_name, &sub_at, &de);
if (ret == DW_DLV_ERROR)
goto done;
if (ret == DW_DLV_OK) {
if (dwarf_formstring(sub_at, &func0, &de) ==
DW_DLV_OK) {
free(*rlt_func);
if ((*rlt_func = strdup(func0)) == NULL)
err(EXIT_FAILURE, "strdup");
}
goto done;
}
/*
* If DW_AT_name is not present, but DW_AT_specification is
* present, then probably the actual name is in the DIE
* referenced by DW_AT_specification.
*/
if (dwarf_attr(die, DW_AT_specification, &spec_at, &de))
goto done;
if (dwarf_global_formref(spec_at, &ref, &de))
goto done;
if (dwarf_offdie(dbg, ref, &spec_die, &de))
goto done;
if (dwarf_attrval_string(spec_die, DW_AT_name, &func1, &de) ==
DW_DLV_OK) {
free(*rlt_func);
if ((*rlt_func = strdup(func1)) == NULL)
err(EXIT_FAILURE, "strdup");
}
goto done;
}
cont_search:
/* Search children. */
ret = dwarf_child(die, &ret_die, &de);
if (ret == DW_DLV_ERROR)
errx(EXIT_FAILURE, "dwarf_child: %s", dwarf_errmsg(de));
else if (ret == DW_DLV_OK)
search_func(dbg, ret_die, addr, rlt_func);
/* Search sibling. */
ret = dwarf_siblingof(dbg, die, &ret_die, &de);
if (ret == DW_DLV_ERROR)
errx(EXIT_FAILURE, "dwarf_siblingof: %s", dwarf_errmsg(de));
else if (ret == DW_DLV_OK)
search_func(dbg, ret_die, addr, rlt_func);
done:
dwarf_dealloc(dbg, die, DW_DLA_DIE);
}
