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// Setup routines for creating fully populated DWFLs. Used in pass 2 and 3.
// Copyright (C) 2009 Red Hat, Inc.
//
// This file is part of systemtap, and is free software. You can
// redistribute it and/or modify it under the terms of the GNU General
// Public License (GPL); either version 2, or (at your option) any
// later version.
#include "config.h"
#include "setupdwfl.h"
#include "dwarf_wrappers.h"
#include "dwflpp.h"
#include "session.h"
#include <set>
#include <string>
extern "C" {
#include <fnmatch.h>
#include <stdlib.h>
}
static const char *debuginfo_path_arr = "+:.debug:/usr/lib/debug:build";
static const char *debuginfo_env_arr = getenv("SYSTEMTAP_DEBUGINFO_PATH");
static const char *debuginfo_path = (debuginfo_env_arr ?: debuginfo_path_arr);
static const Dwfl_Callbacks kernel_callbacks =
{
dwfl_linux_kernel_find_elf,
dwfl_standard_find_debuginfo,
dwfl_offline_section_address,
(char **) & debuginfo_path
};
using namespace std;
// Setup in setup_dwfl_kernel(), for use in setup_dwfl_report_kernel_p().
// Either offline_search_modname or offline_search_names is
// used. When offline_search_modname is not NULL then
// offline_search_names is ignored.
static const char *offline_search_modname;
static set<string> offline_search_names;
static unsigned *offline_modules_found;
// Set up our offline search for kernel modules. We don't want the
// offline search iteration to do a complete search of the kernel
// build tree, since that's wasteful, so create a predicate that
// filters and stops reporting as soon as we got everything.
static int
setup_dwfl_report_kernel_p(const char* modname, const char* filename)
{
if (pending_interrupts)
return -1;
// elfutils sends us NULL filenames sometimes if it can't find dwarf
if (filename == NULL)
return 0;
// If offline_search_modname is setup use it (either as regexp or
// explicit module/kernel name) and ignore offline_search_names.
// Otherwise use offline_search_names exclusively.
if (offline_search_modname != NULL)
{
if (dwflpp::name_has_wildcard (offline_search_modname))
{
int match_p = !fnmatch(offline_search_modname, modname, 0);
// In the wildcard case, we don't short-circuit (return -1)
// analogously to dwflpp::module_name_final_match().
if (match_p)
(*offline_modules_found)++;
return match_p;
}
else
{ /* non-wildcard mode */
if (*offline_modules_found)
return -1; // Done, only one name needed and found it.
/* Reject mismatching module names */
if (strcmp(modname, offline_search_modname))
return 0;
else
{
(*offline_modules_found)++;
return 1;
}
}
}
else
{ /* find all in set mode */
if (offline_search_names.empty())
return -1;
/* Reject mismatching module names */
if (offline_search_names.find(modname) == offline_search_names.end())
return 0;
else
{
offline_search_names.erase(modname);
(*offline_modules_found)++;
return 1;
}
}
}
static Dwfl *
setup_dwfl_kernel (unsigned *modules_found, systemtap_session &s)
{
Dwfl *dwfl = dwfl_begin (&kernel_callbacks);
dwfl_assert ("dwfl_begin", dwfl);
dwfl_report_begin (dwfl);
// We have a problem with -r REVISION vs -r BUILDDIR here. If
// we're running against a fedora/rhel style kernel-debuginfo
// tree, s.kernel_build_tree is not the place where the unstripped
// vmlinux will be installed. Rather, it's over yonder at
// /usr/lib/debug/lib/modules/$REVISION/. It seems that there is
// no way to set the dwfl_callback.debuginfo_path and always
// passs the plain kernel_release here. So instead we have to
// hard-code this magic here.
string elfutils_kernel_path;
if (s.kernel_build_tree == string("/lib/modules/"
+ s.kernel_release
+ "/build"))
elfutils_kernel_path = s.kernel_release;
else
elfutils_kernel_path = s.kernel_build_tree;
offline_modules_found = modules_found;
*offline_modules_found = 0;
int rc = dwfl_linux_kernel_report_offline (dwfl,
elfutils_kernel_path.c_str(),
&setup_dwfl_report_kernel_p);
(void) rc; /* Ignore since the predicate probably returned -1 at some point,
And libdwfl interprets that as "whole query failed" rather than
"found it already, stop looking". */
// NB: the result of an _offline call is the assignment of
// virtualized addresses to relocatable objects such as
// modules. These have to be converted to real addresses at
// run time. See the dwarf_derived_probe ctor and its caller.
dwfl_assert ("dwfl_report_end", dwfl_report_end(dwfl, NULL, NULL));
return dwfl;
}
Dwfl*
setup_dwfl_kernel(const std::string &name,
unsigned *found,
systemtap_session &s)
{
offline_search_modname = name.c_str();
offline_search_names.clear();
return setup_dwfl_kernel(found, s);
}
Dwfl*
setup_dwfl_kernel(const std::set<std::string> &names,
unsigned *found,
systemtap_session &s)
{
offline_search_modname = NULL;
offline_search_names = names;
return setup_dwfl_kernel(found, s);
}
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