i32 csdbg::tracer::on_dso_load ( dl_phdr_info *  dso, size_t  sz, void *  arg  )

staticprotected

This is a dl_iterate_phdr (libdl) callback, called for each linked shared object. It loads the symbol table of the DSO (if it's not filtered out) to tracer::m_iface->m_proc.

Parameters

[in]	dso	a dl_phdr_info struct (libdl) that describes the shared object (file path, load address e.t.c)
[in]	sz	the sizeof dso
[in]	arg	a chain of POSIX extended regular expressions used to select the shared objects that will participate in the call stack simulation. The absolute path of each DSO is matched against each regexp. If NULL, all linked DSO symbol tables will be loaded. If not NULL but empty, all DSO are filtered out from instrumentation

Returns

0

Note

If an exception occurs, it's caught and handled. 0 is returned, signaling to the iterator (dl_iterate_phdr) to continue with the next DSO

Definition at line 323 of file tracer.cpp.

References csdbg::process::add_module(), csdbg::chain< T >::at(), csdbg::string::cstr(), csdbg::util::dbg_error(), csdbg::util::dbg_warn(), csdbg::string::length(), likely, m_iface, m_proc, csdbg::string::match(), csdbg::exception::msg(), csdbg::chain< T >::size(), and unlikely.

Referenced by on_lib_load().

{
  try {
    if ( unlikely(dso == NULL) )
      throw exception("invalid argument: dso (=%p)", dso);

    /* If the DSO path is undefined */
    string path(dso->dlpi_name);
    if ( unlikely(path.length() == 0) )
      throw exception("undefined DSO path");

    /* If the DSO has no segments */
    if ( unlikely(dso->dlpi_phnum == 0) )
      throw exception("'%s' has 0 segments", path.cstr());

    /* Check if the DSO is filtered out */
    bool found = false;
    if ( likely(arg != NULL) ) {
      chain<string> *filters = static_cast<chain<string>*> (arg);

      for (u32 i = 0, sz = filters->size(); likely(i < sz); i++) {
        string *filt = filters->at(i);
        if ( unlikely(path.match(*filt)) ) {
          found = true;
          break;
        }
      }
    }
    else
      found = true;

    if ( likely(!found) ) {
      util::dbg_warn("filtered out '%s'", path.cstr());
      return 0;
    }

    /* Load the DSO symbol table */
    mem_addr_t base = dso->dlpi_addr + dso->dlpi_phdr[0].p_vaddr;
    m_iface->m_proc->add_module(path.cstr(), base);
  }

  catch (exception &x) {
    util::dbg_error("in tracer::%s(): %s", __FUNCTION__, x.msg());
  }

  catch (std::exception &x) {
    util::dbg_error("in tracer::%s(): %s", __FUNCTION__, x.what());
  }

  return 0;
}

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