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/*
* Copyright (c) 2016 Facebook, Inc.
*
* 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 <errno.h>
#include <unistd.h>
#include <cstring>
#include <iostream>
#include "BPFTable.h"
#include "bcc_exception.h"
#include "bcc_syms.h"
#include "libbpf.h"
#include "perf_reader.h"
#include "common.h"
namespace ebpf {
BPFStackTable::~BPFStackTable() {
for (auto it : pid_sym_)
bcc_free_symcache(it.second, it.first);
}
std::vector<intptr_t> BPFStackTable::get_stack_addr(int stack_id) {
std::vector<intptr_t> res;
stacktrace_t stack;
if (!lookup(&stack_id, &stack))
return res;
for (int i = 0; (i < BPF_MAX_STACK_DEPTH) && (stack.ip[i] != 0); i++)
res.push_back(stack.ip[i]);
return res;
}
std::vector<std::string> BPFStackTable::get_stack_symbol(int stack_id,
int pid) {
auto addresses = get_stack_addr(stack_id);
std::vector<std::string> res;
res.reserve(addresses.size());
if (pid < 0)
pid = -1;
if (pid_sym_.find(pid) == pid_sym_.end())
pid_sym_[pid] = bcc_symcache_new(pid);
void* cache = pid_sym_[pid];
bcc_symbol symbol;
for (auto addr : addresses)
if (bcc_symcache_resolve(cache, addr, &symbol) != 0)
res.push_back("[UNKNOWN]");
else
res.push_back(symbol.demangle_name);
return res;
}
StatusTuple BPFPerfBuffer::open_on_cpu(perf_reader_raw_cb cb, int cpu,
void* cb_cookie) {
if (cpu_readers_.find(cpu) != cpu_readers_.end())
return StatusTuple(-1, "Perf buffer already open on CPU %d", cpu);
auto reader =
static_cast<perf_reader*>(bpf_open_perf_buffer(cb, cb_cookie, -1, cpu));
if (reader == nullptr)
return StatusTuple(-1, "Unable to construct perf reader");
int reader_fd = perf_reader_fd(reader);
if (!update(&cpu, &reader_fd)) {
perf_reader_free(static_cast<void*>(reader));
return StatusTuple(-1, "Unable to open perf buffer on CPU %d: %s", cpu,
strerror(errno));
}
cpu_readers_[cpu] = reader;
readers_.push_back(reader);
return StatusTuple(0);
}
StatusTuple BPFPerfBuffer::open_all_cpu(perf_reader_raw_cb cb,
void* cb_cookie) {
if (cpu_readers_.size() != 0 || readers_.size() != 0)
return StatusTuple(-1, "Previously opened perf buffer not cleaned");
for (int i: get_online_cpus()) {
auto res = open_on_cpu(cb, i, cb_cookie);
if (res.code() != 0) {
TRY2(close_all_cpu());
return res;
}
}
return StatusTuple(0);
}
StatusTuple BPFPerfBuffer::close_on_cpu(int cpu) {
auto it = cpu_readers_.find(cpu);
if (it == cpu_readers_.end())
return StatusTuple(0);
perf_reader_free(static_cast<void*>(it->second));
if (!remove(const_cast<int*>(&(it->first))))
return StatusTuple(-1, "Unable to close perf buffer on CPU %d", it->first);
cpu_readers_.erase(it);
return StatusTuple(0);
}
StatusTuple BPFPerfBuffer::close_all_cpu() {
std::string errors;
bool has_error = false;
for (int i: get_online_cpus()) {
auto res = close_on_cpu(i);
if (res.code() != 0) {
errors += "Failed to close CPU" + std::to_string(i) + " perf buffer: ";
errors += res.msg() + "\n";
has_error = true;
}
}
readers_.clear();
if (has_error)
return StatusTuple(-1, errors);
return StatusTuple(0);
}
void BPFPerfBuffer::poll(int timeout) {
if (readers_.empty())
return;
perf_reader_poll(readers_.size(), readers_.data(), timeout);
}
BPFPerfBuffer::~BPFPerfBuffer() {
auto res = close_all_cpu();
if (res.code() != 0)
std::cerr << "Failed to close all perf buffer on destruction: "
<< res.msg() << std::endl;
}
} // namespace ebpf