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/*
* Copyright (C) 2020 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "ProbeEvents.h"
#include <inttypes.h>
#include <memory>
#include <string>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/parseint.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include <android-base/unique_fd.h>
#include "RegEx.h"
#include "environment.h"
#include "event_selection_set.h"
#include "event_type.h"
#include "utils.h"
namespace simpleperf {
using android::base::ParseInt;
using android::base::ParseUint;
using android::base::Split;
using android::base::StringPrintf;
using android::base::unique_fd;
using android::base::WriteStringToFd;
static const std::string kKprobeEventPrefix = "kprobes:";
bool ProbeEvents::ParseKprobeEventName(const std::string& kprobe_cmd, ProbeEvent* event) {
// kprobe_cmd is in formats described in <kernel>/Documentation/trace/kprobetrace.rst:
// p[:[GRP/]EVENT] [MOD:]SYM[+offs]|MEMADDR [FETCHARGS]
// r[MAXACTIVE][:[GRP/]EVENT] [MOD:]SYM[+offs] [FETCHARGS]
std::vector<std::string> args = Split(kprobe_cmd, " ");
if (args.size() < 2) {
return false;
}
// Parse given name.
event->group_name = "kprobes";
auto name_reg = RegEx::Create(R"(:([a-zA-Z_][\w_]*/)?([a-zA-Z_][\w_]*))");
auto match = name_reg->SearchAll(args[0]);
if (match->IsValid()) {
if (match->GetField(1).length() > 0) {
event->group_name = match->GetField(1);
event->group_name.pop_back();
}
event->event_name = match->GetField(2);
return true;
}
// Generate name from MEMADDR.
char probe_type = args[0][0];
uint64_t kaddr;
if (ParseUint(args[1], &kaddr)) {
event->event_name = StringPrintf("%c_0x%" PRIx64, probe_type, kaddr);
return true;
}
// Generate name from [MOD:]SYM[+offs].
std::string symbol;
int64_t offset;
size_t split_pos = args[1].find_first_of("+-");
if (split_pos == std::string::npos) {
symbol = args[1];
offset = 0;
} else {
symbol = args[1].substr(0, split_pos);
if (!ParseInt(args[1].substr(split_pos), &offset) || offset < 0) {
return false;
}
}
std::string s = StringPrintf("%c_%s_%" PRId64, probe_type, symbol.c_str(), offset);
event->event_name = RegEx::Create(R"(\.|:)")->Replace(s, "_").value();
return true;
}
ProbeEvents::~ProbeEvents() {
if (!IsEmpty()) {
// Probe events can be deleted only when no perf event file is using them.
event_selection_set_.CloseEventFiles();
Clear();
}
}
bool ProbeEvents::IsKprobeSupported() {
if (!kprobe_control_path_.has_value()) {
kprobe_control_path_ = "";
if (const char* tracefs_dir = GetTraceFsDir(); tracefs_dir != nullptr) {
std::string path = std::string(tracefs_dir) + "/kprobe_events";
if (IsRegularFile(path)) {
kprobe_control_path_ = std::move(path);
}
}
}
return !kprobe_control_path_.value().empty();
}
bool ProbeEvents::AddKprobe(const std::string& kprobe_cmd) {
ProbeEvent event;
if (!ParseKprobeEventName(kprobe_cmd, &event)) {
LOG(ERROR) << "invalid kprobe cmd: " << kprobe_cmd;
return false;
}
if (!WriteKprobeCmd(kprobe_cmd)) {
return false;
}
kprobe_events_.emplace_back(std::move(event));
return true;
}
bool ProbeEvents::IsProbeEvent(const std::string& event_name) {
return android::base::StartsWith(event_name, kKprobeEventPrefix);
}
bool ProbeEvents::CreateProbeEventIfNotExist(const std::string& event_name) {
if (!IsProbeEvent(event_name) || (EventTypeManager::Instance().FindType(event_name) != nullptr)) {
// No need to create a probe event.
return true;
}
std::string function_name = event_name.substr(kKprobeEventPrefix.size());
return AddKprobe(StringPrintf("p:%s %s", function_name.c_str(), function_name.c_str()));
}
void ProbeEvents::Clear() {
for (const auto& kprobe_event : kprobe_events_) {
if (!WriteKprobeCmd("-:" + kprobe_event.group_name + "/" + kprobe_event.event_name)) {
LOG(WARNING) << "failed to delete kprobe event " << kprobe_event.group_name << ":"
<< kprobe_event.event_name;
}
EventTypeManager::Instance().RemoveProbeType(kprobe_event.group_name + ":" +
kprobe_event.event_name);
}
kprobe_events_.clear();
}
bool ProbeEvents::WriteKprobeCmd(const std::string& kprobe_cmd) {
if (!IsKprobeSupported()) {
LOG(ERROR) << "kprobe events isn't supported by the kernel.";
return false;
}
const std::string& path = kprobe_control_path_.value();
unique_fd fd(open(path.c_str(), O_APPEND | O_WRONLY | O_CLOEXEC));
if (!fd.ok()) {
PLOG(ERROR) << "failed to open " << path;
return false;
}
if (!WriteStringToFd(kprobe_cmd, fd)) {
PLOG(ERROR) << "failed to write '" << kprobe_cmd << "' to " << path;
return false;
}
return true;
}
} // namespace simpleperf
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