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// tapset for debuginfod searching
// Copyright (C) 2005-2023 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 "session.h"
#include "tapsets.h"
#include "translate.h"
#include "util.h"
#include "fnmatch.h"
#if defined(HAVE_LIBDEBUGINFOD) && defined(HAVE_JSON_C) && defined(METADATA_QUERY_ENABLED)
#include <elfutils/debuginfod.h>
#include <json-c/json.h>
#include <unistd.h>
using namespace std;
using namespace __gnu_cxx;
static const string TOK_DEBUGINFOD("debuginfod");
static const string TOK_ARCHIVE("archive");
static const string TOK_PROCESS("process");
struct metadata_result { string archive; string file; };
map<string,metadata_result>
get_buildids(bool has_archive, string archive, string process_path) {
static unique_ptr <debuginfod_client, void (*)(debuginfod_client*)>
client (debuginfod_begin(), &debuginfod_end);
map<string,metadata_result> buildids;
int metadata_fd;
if((metadata_fd = debuginfod_find_metadata(client.get(), "glob", (char*)process_path.c_str(), NULL)) < 0)
throw SEMANTIC_ERROR(_("can't retrieve buildids from debuginfod"));
vector<pid_t> debuginfod_workers;
json_object *metadata = json_object_from_fd(metadata_fd);
json_object *metadata_array;
close(metadata_fd);
if(!metadata || !json_object_object_get_ex(metadata, "results", &metadata_array))
throw SEMANTIC_ERROR(_("retrieved invalid buildids from debuginfod"));
size_t n_bid = json_object_array_length(metadata_array);
if(0 == n_bid)
throw SEMANTIC_ERROR(_("can't retrieve buildids from debuginfod"));
int d_out, d_err;
json_object *file_metadata, *json_field;
string buildid;
for(size_t i = 0; i < n_bid; i++)
{
file_metadata = json_object_array_get_idx(metadata_array, i);
// Reject missing buildid
if(json_object_object_get_ex(file_metadata, "buildid", &json_field))
buildid = json_object_get_string(json_field);
else
continue;
// Reject sus buildids
if(! is_build_id(buildid))
continue;
// Reject duplicate buildid - they are equivalent as far as we're concerned
if (buildids.find(buildid) != buildids.end())
continue;
// Reject non-executables
if (! (json_object_object_get_ex(file_metadata, "type", &json_field)
&& 0 == strcmp(json_object_get_string(json_field), "executable")))
continue;
// Extract archive name (if any - might be empty).
string archive_fullname;
if (json_object_object_get_ex(file_metadata, "archive", &json_field)) {
archive_fullname = json_object_get_string(json_field);
}
string archive_basename = archive_fullname.substr(archive_fullname.find_last_of("/") + 1);
// Reject mismatching archive, if user specified
if (has_archive) {
// documented as basename comparison, so no FNM_PATHNAME needed
if(0 != fnmatch(archive.c_str(), archive_basename.c_str(), 0))
continue;
}
// Extract file name (mandatory)
string filename;
if (json_object_object_get_ex(file_metadata, "file", &json_field))
filename = json_object_get_string(json_field);
else
continue;
metadata_result af; af.archive = archive_basename; af.file = filename;
buildids.insert(make_pair(buildid, af));
debuginfod_workers.push_back(stap_spawn_piped(0, {"debuginfod-find", "executable", buildid}, NULL, &d_out, &d_err));
// NB: we don't really have to preload the debuginfo - a probe point may not call for dwarf
// NB: but if it does, we'd suffer latency by downloading one at a time, sequentially
debuginfod_workers.push_back(stap_spawn_piped(0, {"debuginfod-find", "debuginfo" , buildid}, NULL, &d_out, &d_err));
}
json_object_put(metadata);
// Make sure all the executables/debuginfo are found before continuing
for(auto worker_pid = debuginfod_workers.begin(); worker_pid != debuginfod_workers.end(); ++worker_pid)
if(*worker_pid > 0) stap_waitpid(0, *worker_pid);
return buildids;
}
// ------------------------------------------------------------------------
// debuginfod_builder derived probes
// ------------------------------------------------------------------------
struct debuginfod_builder: public derived_probe_builder
{
public:
void build(systemtap_session & sess, probe * base,
probe_point * location,
literal_map_t const & parameters,
vector<derived_probe *> & finished_results);
void build_with_suffix(systemtap_session & sess, probe * base,
probe_point * location,
literal_map_t const & parameters,
std::vector<derived_probe *> & finished_results,
std::vector<probe_point::component *> const & suffix);
virtual string name() { return "debuginfod builder"; }
};
void
debuginfod_builder::build(systemtap_session & sess, probe * base,
probe_point * location,
literal_map_t const & parameters,
vector<derived_probe *> & finished_results)
{
interned_string archive;
interned_string process_path;
bool has_debuginfod = has_null_param (parameters, TOK_DEBUGINFOD);
bool has_process = get_param (parameters, TOK_PROCESS, process_path);
bool has_archive = get_param (parameters, TOK_ARCHIVE, archive);
if(!has_debuginfod || !has_process)
throw SEMANTIC_ERROR(_("the probe must be of the form debuginfod.[.archive(\"foobar\")]process(\"foo/bar\").**{...}"));
// The matching buildids from the archives/debuginfod
map<string,metadata_result> buildids = get_buildids(has_archive, archive, process_path);
for(auto it = buildids.begin(); it != buildids.end(); ++it) {
interned_string buildid = it->first;
interned_string m_archive = it->second.archive;
interned_string m_file = it->second.file;
probe *subbase = base;
probe_point *subbase_pp = location;
if (sess.verbose > 3) {
clog << "from: ";
subbase->printsig(clog);
}
// If the probe archive/process names were globs, interject an intermediate
// probe into the chain that resolves the globs.
if (process_path.find_first_of("*?[{") != string::npos ||
(has_archive && archive.find_first_of("*?[{") != string::npos)) // was some globbing performed?
{
subbase_pp = new probe_point(*location);
if (has_archive) {
assert (subbase_pp->components[1]->functor == TOK_ARCHIVE);
subbase_pp->components[1] = new probe_point::component(TOK_ARCHIVE,
new literal_string(m_archive),
false);
assert (subbase_pp->components[2]->functor == TOK_PROCESS);
subbase_pp->components[2] = new probe_point::component(TOK_PROCESS,
new literal_string(m_file),
false);
} else {
assert (subbase_pp->components[1]->functor == TOK_PROCESS);
subbase_pp->components[1] = new probe_point::component(TOK_PROCESS,
new literal_string(m_file),
false);
}
// subbase_pp->well_formed = true; // XXX: true, unless the FUNCTION etc. stuff has *
subbase = new probe(base, subbase_pp);
if (sess.verbose > 3) {
clog << " through: ";
subbase->printsig(clog);
}
}
// OK time for the new process("buildid").foo probe
probe_point *derived_pp = new probe_point(*subbase_pp);
derived_pp->components.erase(derived_pp->components.begin()); // Remove the 'debuginfod'
if (has_archive)
derived_pp->components.erase(derived_pp->components.begin()); // Remove the 'archive' too
assert (derived_pp->components[0]->functor == TOK_PROCESS);
// NB: since probe_points are shallow-copied, we must not modify a
// preexisting component, but create new
derived_pp->components[0] = new probe_point::component(TOK_PROCESS,
new literal_string(buildid),
false);
derived_pp->optional = true; // even if not from a glob, to accept wrong-arch buildids
// derived_pp->well_formed = true; // XXX: true, unless the FUNCTION etc. stuff has *
probe *derived_p = new probe(subbase, derived_pp);
if (sess.verbose > 3) {
clog << " to: ";
derived_p->printsig(clog);
clog << endl;
}
if (sess.verbose > 2)
clog << _F("resolved debuginfod archive %s file %s -> buildid %s archive %s file %s",
has_archive ? archive.to_string().c_str() : "?",
process_path.to_string().c_str(),
buildid.to_string().c_str(),
m_archive.to_string().c_str(),
m_file.to_string().c_str())
<< endl;
vector<derived_probe *> results;
derive_probes(sess, derived_p, results, false, true);
finished_results.insert(finished_results.end(), results.begin(), results.end());
}
}
void
debuginfod_builder::build_with_suffix(systemtap_session & sess, probe * base,
probe_point * location,
literal_map_t const &,
std::vector<derived_probe *> & finished_results,
std::vector<probe_point::component *> const & suffix){
/* Extract the parameters for the head of the probe
* The probes are of the form debuginfod[.archive(**)].process("foo/bar").**.
* So the length should always be TWO (2) or THREE (3),
* when a archive parameter is provided.
*/
unsigned num_param = location->components.size() - suffix.size();
assert(num_param == 2 || num_param == 3);
literal_map_t param_map;
for (unsigned i=0; i<num_param; i++)
param_map[location->components[i]->functor] = location->components[i]->arg;
build(sess, base, location, param_map, finished_results);
return;
}
void
register_tapset_debuginfod(systemtap_session& s)
{
match_node* root = s.pattern_root;
derived_probe_builder *builder = new debuginfod_builder();
// All suffixes will get caught and processed by build_with_suffix
//debuginfod.process()
root->bind(TOK_DEBUGINFOD)->bind_str(TOK_PROCESS)->bind(builder);
//debuginfod.archive().process()
root->bind(TOK_DEBUGINFOD)->bind_str(TOK_ARCHIVE)->bind_str(TOK_PROCESS)->bind(builder);
}
#else /* no DEBUGINFOD and/or no JSON */
void
register_tapset_debuginfod(systemtap_session& s)
{
(void) s;
}
#endif
/* vim: set sw=2 ts=8 cino=>4,n-2,{2,^-2,t0,(0,u0,w1,M1 : */
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