bool BacktraceOffline::FindProcInfo(unw_addr_space_t addr_space, uint64_t ip,
unw_proc_info_t* proc_info, int need_unwind_info) {
backtrace_map_t map;
FillInMap(ip, &map);
if (!BacktraceMap::IsValid(map)) {
return false;
}
const std::string& filename = map.name;
DebugFrameInfo* debug_frame = GetDebugFrameInFile(filename);
if (debug_frame == nullptr) {
return false;
}
if (debug_frame->is_eh_frame) {
uint64_t ip_offset = ip - map.start + map.offset;
uint64_t ip_vaddr; // vaddr in the elf file.
bool result = FileOffsetToVaddr(debug_frame->eh_frame.program_headers, ip_offset, &ip_vaddr);
if (!result) {
return false;
}
// Calculate the addresses where .eh_frame_hdr and .eh_frame stay when the process was running.
eh_frame_hdr_space_.start = (ip - ip_vaddr) + debug_frame->eh_frame.eh_frame_hdr_vaddr;
eh_frame_hdr_space_.end =
eh_frame_hdr_space_.start + debug_frame->eh_frame.eh_frame_hdr_data.size();
eh_frame_hdr_space_.data = debug_frame->eh_frame.eh_frame_hdr_data.data();
eh_frame_space_.start = (ip - ip_vaddr) + debug_frame->eh_frame.eh_frame_vaddr;
eh_frame_space_.end = eh_frame_space_.start + debug_frame->eh_frame.eh_frame_data.size();
eh_frame_space_.data = debug_frame->eh_frame.eh_frame_data.data();
unw_dyn_info di;
memset(&di, '\0', sizeof(di));
di.start_ip = map.start;
di.end_ip = map.end;
di.format = UNW_INFO_FORMAT_REMOTE_TABLE;
di.u.rti.name_ptr = 0;
di.u.rti.segbase = eh_frame_hdr_space_.start;
di.u.rti.table_data =
eh_frame_hdr_space_.start + debug_frame->eh_frame.fde_table_offset_in_eh_frame_hdr;
di.u.rti.table_len = (eh_frame_hdr_space_.end - di.u.rti.table_data) / sizeof(unw_word_t);
int ret = dwarf_search_unwind_table(addr_space, ip, &di, proc_info, need_unwind_info, this);
return ret == 0;
}
eh_frame_hdr_space_.Clear();
eh_frame_space_.Clear();
unw_dyn_info_t di;
unw_word_t segbase = map.start - map.offset;
int found = dwarf_find_debug_frame(0, &di, ip, segbase, filename.c_str(), map.start, map.end);
if (found == 1) {
int ret = dwarf_search_unwind_table(addr_space, ip, &di, proc_info, need_unwind_info, this);
return ret == 0;
}
return false;
}
int main(void)
{
dwarf_find_debug_frame(0, NULL, 0, 0, NULL, 0, 0);
return 0;
}
