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649 lines (566 loc) · 21.3 KB
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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 <linux/bpf.h>
#include <linux/perf_event.h>
#include <unistd.h>
#include <cstdio>
#include <cstring>
#include <exception>
#include <iostream>
#include <memory>
#include <sstream>
#include <utility>
#include <vector>
#include "bcc_exception.h"
#include "bcc_syms.h"
#include "bpf_module.h"
#include "common.h"
#include "libbpf.h"
#include "perf_reader.h"
#include "table_storage.h"
#include "usdt.h"
#include "BPF.h"
namespace ebpf {
std::string uint_to_hex(uint64_t value) {
std::stringstream ss;
ss << std::hex << value;
return ss.str();
}
std::string sanitize_str(std::string str, bool (*validator)(char),
char replacement = '_') {
for (size_t i = 0; i < str.length(); i++)
if (!validator(str[i]))
str[i] = replacement;
return str;
}
StatusTuple BPF::init(const std::string& bpf_program,
const std::vector<std::string>& cflags,
const std::vector<USDT>& usdt) {
std::string all_bpf_program;
for (auto u : usdt) {
if (!u.initialized_)
TRY2(u.init());
all_bpf_program += u.program_text_;
usdt_.push_back(std::move(u));
}
auto flags_len = cflags.size();
const char* flags[flags_len];
for (size_t i = 0; i < flags_len; i++)
flags[i] = cflags[i].c_str();
all_bpf_program += bpf_program;
if (bpf_module_->load_string(all_bpf_program, flags, flags_len) != 0)
return StatusTuple(-1, "Unable to initialize BPF program");
return StatusTuple(0);
};
BPF::~BPF() {
auto res = detach_all();
if (res.code() != 0)
std::cerr << "Failed to detach all probes on destruction: " << std::endl
<< res.msg() << std::endl;
}
StatusTuple BPF::detach_all() {
bool has_error = false;
std::string error_msg;
for (auto& it : kprobes_) {
auto res = detach_kprobe_event(it.first, it.second);
if (res.code() != 0) {
error_msg += "Failed to detach kprobe event " + it.first + ": ";
error_msg += res.msg() + "\n";
has_error = true;
}
}
for (auto& it : uprobes_) {
auto res = detach_uprobe_event(it.first, it.second);
if (res.code() != 0) {
error_msg += "Failed to detach uprobe event " + it.first + ": ";
error_msg += res.msg() + "\n";
has_error = true;
}
}
for (auto& it : tracepoints_) {
auto res = detach_tracepoint_event(it.first, it.second);
if (res.code() != 0) {
error_msg += "Failed to detach Tracepoint " + it.first + ": ";
error_msg += res.msg() + "\n";
has_error = true;
}
}
for (auto& it : perf_buffers_) {
auto res = it.second->close_all_cpu();
if (res.code() != 0) {
error_msg += "Failed to close perf buffer " + it.first + ": ";
error_msg += res.msg() + "\n";
has_error = true;
}
delete it.second;
}
for (auto& it : perf_event_arrays_) {
auto res = it.second->close_all_cpu();
if (res.code() != 0) {
error_msg += "Failed to close perf event array " + it.first + ": ";
error_msg += res.msg() + "\n";
has_error = true;
}
delete it.second;
}
for (auto& it : perf_events_) {
auto res = detach_perf_event_all_cpu(it.second);
if (res.code() != 0) {
error_msg += res.msg() + "\n";
has_error = true;
}
}
for (auto& it : funcs_) {
int res = close(it.second);
if (res != 0) {
error_msg += "Failed to unload BPF program for " + it.first + ": ";
error_msg += std::string(std::strerror(errno)) + "\n";
has_error = true;
}
}
if (has_error)
return StatusTuple(-1, error_msg);
else
return StatusTuple(0);
}
StatusTuple BPF::attach_kprobe(const std::string& kernel_func,
const std::string& probe_func,
bpf_probe_attach_type attach_type,
pid_t pid, int cpu, int group_fd,
perf_reader_cb cb, void* cb_cookie) {
std::string probe_event = get_kprobe_event(kernel_func, attach_type);
if (kprobes_.find(probe_event) != kprobes_.end())
return StatusTuple(-1, "kprobe %s already attached", probe_event.c_str());
int probe_fd;
TRY2(load_func(probe_func, BPF_PROG_TYPE_KPROBE, probe_fd));
void* res =
bpf_attach_kprobe(probe_fd, attach_type, probe_event.c_str(), kernel_func.c_str(),
pid, cpu, group_fd, cb, cb_cookie);
if (!res) {
TRY2(unload_func(probe_func));
return StatusTuple(-1, "Unable to attach %skprobe for %s using %s",
attach_type_debug(attach_type).c_str(),
kernel_func.c_str(), probe_func.c_str());
}
open_probe_t p = {};
p.reader_ptr = res;
p.func = probe_func;
kprobes_[probe_event] = std::move(p);
return StatusTuple(0);
}
StatusTuple BPF::attach_uprobe(const std::string& binary_path,
const std::string& symbol,
const std::string& probe_func,
uint64_t symbol_addr,
bpf_probe_attach_type attach_type,
pid_t pid, int cpu, int group_fd,
perf_reader_cb cb, void* cb_cookie) {
std::string module;
uint64_t offset;
TRY2(check_binary_symbol(binary_path, symbol, symbol_addr, module, offset));
std::string probe_event = get_uprobe_event(module, offset, attach_type, pid);
if (uprobes_.find(probe_event) != uprobes_.end())
return StatusTuple(-1, "uprobe %s already attached", probe_event.c_str());
int probe_fd;
TRY2(load_func(probe_func, BPF_PROG_TYPE_KPROBE, probe_fd));
void* res =
bpf_attach_uprobe(probe_fd, attach_type, probe_event.c_str(), binary_path.c_str(),
offset, pid, cpu, group_fd, cb, cb_cookie);
if (!res) {
TRY2(unload_func(probe_func));
return StatusTuple(
-1,
"Unable to attach %suprobe for binary %s symbol %s addr %lx using %s\n",
attach_type_debug(attach_type).c_str(), binary_path.c_str(),
symbol.c_str(), symbol_addr, probe_func.c_str());
}
open_probe_t p = {};
p.reader_ptr = res;
p.func = probe_func;
uprobes_[probe_event] = std::move(p);
return StatusTuple(0);
}
StatusTuple BPF::attach_usdt(const USDT& usdt, pid_t pid, int cpu,
int group_fd) {
for (const auto& u : usdt_)
if (u == usdt) {
bool failed = false;
std::string err_msg;
int cnt = 0;
for (auto addr : u.addresses_) {
auto res =
attach_uprobe(u.binary_path_, std::string(), u.probe_func_, addr);
if (res.code() != 0) {
failed = true;
err_msg += "USDT " + u.print_name() + " at " + std::to_string(addr);
err_msg += ": " + res.msg() + "\n";
break;
}
cnt++;
}
if (failed) {
for (int i = 0; i < cnt; i++) {
auto res =
detach_uprobe(u.binary_path_, std::string(), u.addresses_[i]);
err_msg += "During clean up: " + res.msg() + "\n";
}
return StatusTuple(-1, err_msg);
} else
return StatusTuple(0);
}
return StatusTuple(-1, "USDT %s not found", usdt.print_name().c_str());
}
StatusTuple BPF::attach_tracepoint(const std::string& tracepoint,
const std::string& probe_func,
pid_t pid, int cpu, int group_fd,
perf_reader_cb cb, void* cb_cookie) {
if (tracepoints_.find(tracepoint) != tracepoints_.end())
return StatusTuple(-1, "Tracepoint %s already attached",
tracepoint.c_str());
auto pos = tracepoint.find(":");
if ((pos == std::string::npos) || (pos != tracepoint.rfind(":")))
return StatusTuple(-1, "Unable to parse Tracepoint %s", tracepoint.c_str());
std::string tp_category = tracepoint.substr(0, pos);
std::string tp_name = tracepoint.substr(pos + 1);
int probe_fd;
TRY2(load_func(probe_func, BPF_PROG_TYPE_TRACEPOINT, probe_fd));
void* res =
bpf_attach_tracepoint(probe_fd, tp_category.c_str(), tp_name.c_str(), pid,
cpu, group_fd, cb, cb_cookie);
if (!res) {
TRY2(unload_func(probe_func));
return StatusTuple(-1, "Unable to attach Tracepoint %s using %s",
tracepoint.c_str(), probe_func.c_str());
}
open_probe_t p = {};
p.reader_ptr = res;
p.func = probe_func;
tracepoints_[tracepoint] = std::move(p);
return StatusTuple(0);
}
StatusTuple BPF::attach_perf_event(uint32_t ev_type, uint32_t ev_config,
const std::string& probe_func,
uint64_t sample_period, uint64_t sample_freq,
pid_t pid, int cpu, int group_fd) {
auto ev_pair = std::make_pair(ev_type, ev_config);
if (perf_events_.find(ev_pair) != perf_events_.end())
return StatusTuple(-1, "Perf event type %d config %d already attached",
ev_type, ev_config);
int probe_fd;
TRY2(load_func(probe_func, BPF_PROG_TYPE_PERF_EVENT, probe_fd));
auto fds = new std::map<int, int>();
std::vector<int> cpus;
if (cpu >= 0)
cpus.push_back(cpu);
else
cpus = get_online_cpus();
for (int i: cpus) {
int fd = bpf_attach_perf_event(probe_fd, ev_type, ev_config, sample_period,
sample_freq, pid, i, group_fd);
if (fd < 0) {
for (const auto& it : *fds)
close(it.second);
delete fds;
TRY2(unload_func(probe_func));
return StatusTuple(-1, "Failed to attach perf event type %d config %d",
ev_type, ev_config);
}
fds->emplace(i, fd);
}
open_probe_t p = {};
p.func = probe_func;
p.per_cpu_fd = fds;
perf_events_[ev_pair] = std::move(p);
return StatusTuple(0);
}
StatusTuple BPF::detach_kprobe(const std::string& kernel_func,
bpf_probe_attach_type attach_type) {
std::string event = get_kprobe_event(kernel_func, attach_type);
auto it = kprobes_.find(event);
if (it == kprobes_.end())
return StatusTuple(-1, "No open %skprobe for %s",
attach_type_debug(attach_type).c_str(),
kernel_func.c_str());
TRY2(detach_kprobe_event(it->first, it->second));
kprobes_.erase(it);
return StatusTuple(0);
}
StatusTuple BPF::detach_uprobe(const std::string& binary_path,
const std::string& symbol, uint64_t symbol_addr,
bpf_probe_attach_type attach_type,
pid_t pid) {
std::string module;
uint64_t offset;
TRY2(check_binary_symbol(binary_path, symbol, symbol_addr, module, offset));
std::string event = get_uprobe_event(module, offset, attach_type, pid);
auto it = uprobes_.find(event);
if (it == uprobes_.end())
return StatusTuple(-1, "No open %suprobe for binary %s symbol %s addr %lx",
attach_type_debug(attach_type).c_str(),
binary_path.c_str(), symbol.c_str(), symbol_addr);
TRY2(detach_uprobe_event(it->first, it->second));
uprobes_.erase(it);
return StatusTuple(0);
}
StatusTuple BPF::detach_usdt(const USDT& usdt) {
for (const auto& u : usdt_)
if (u == usdt) {
bool failed = false;
std::string err_msg;
for (auto addr : u.addresses_) {
auto res = detach_uprobe(u.binary_path_, std::string(), addr);
if (res.code() != 0) {
failed = true;
err_msg += "USDT " + u.print_name() + " at " + std::to_string(addr);
err_msg += ": " + res.msg() + "\n";
}
}
if (failed)
return StatusTuple(-1, err_msg);
else
return StatusTuple(0);
}
return StatusTuple(-1, "USDT %s not found", usdt.print_name().c_str());
}
StatusTuple BPF::detach_tracepoint(const std::string& tracepoint) {
auto it = tracepoints_.find(tracepoint);
if (it == tracepoints_.end())
return StatusTuple(-1, "No open Tracepoint %s", tracepoint.c_str());
TRY2(detach_tracepoint_event(it->first, it->second));
tracepoints_.erase(it);
return StatusTuple(0);
}
StatusTuple BPF::detach_perf_event(uint32_t ev_type, uint32_t ev_config) {
auto it = perf_events_.find(std::make_pair(ev_type, ev_config));
if (it == perf_events_.end())
return StatusTuple(-1, "Perf Event type %d config %d not attached",
ev_type, ev_config);
TRY2(detach_perf_event_all_cpu(it->second));
perf_events_.erase(it);
return StatusTuple(0);
}
StatusTuple BPF::open_perf_event(const std::string& name,
uint32_t type,
uint64_t config) {
if (perf_event_arrays_.find(name) == perf_event_arrays_.end()) {
TableStorage::iterator it;
if (!bpf_module_->table_storage().Find(Path({bpf_module_->id(), name}), it))
return StatusTuple(-1,
"open_perf_event: unable to find table_storage %s",
name.c_str());
perf_event_arrays_[name] = new BPFPerfEventArray(it->second);
}
if (type != PERF_TYPE_RAW && type != PERF_TYPE_HARDWARE)
return StatusTuple(-1, "open_perf_event unsupported type");
auto table = perf_event_arrays_[name];
TRY2(table->open_all_cpu(type, config));
return StatusTuple(0);
}
StatusTuple BPF::close_perf_event(const std::string& name) {
auto it = perf_event_arrays_.find(name);
if (it == perf_event_arrays_.end())
return StatusTuple(-1, "Perf Event for %s not open", name.c_str());
TRY2(it->second->close_all_cpu());
return StatusTuple(0);
}
StatusTuple BPF::open_perf_buffer(const std::string& name,
perf_reader_raw_cb cb,
perf_reader_lost_cb lost_cb,
void* cb_cookie,
int page_cnt) {
if (perf_buffers_.find(name) == perf_buffers_.end()) {
TableStorage::iterator it;
if (!bpf_module_->table_storage().Find(Path({bpf_module_->id(), name}), it))
return StatusTuple(-1,
"open_perf_buffer: unable to find table_storage %s",
name.c_str());
perf_buffers_[name] = new BPFPerfBuffer(it->second);
}
if ((page_cnt & (page_cnt - 1)) != 0)
return StatusTuple(-1, "open_perf_buffer page_cnt must be a power of two");
auto table = perf_buffers_[name];
TRY2(table->open_all_cpu(cb, lost_cb, cb_cookie, page_cnt));
return StatusTuple(0);
}
StatusTuple BPF::close_perf_buffer(const std::string& name) {
auto it = perf_buffers_.find(name);
if (it == perf_buffers_.end())
return StatusTuple(-1, "Perf buffer for %s not open", name.c_str());
TRY2(it->second->close_all_cpu());
return StatusTuple(0);
}
void BPF::poll_perf_buffer(const std::string& name, int timeout) {
auto it = perf_buffers_.find(name);
if (it == perf_buffers_.end())
return;
it->second->poll(timeout);
}
StatusTuple BPF::load_func(const std::string& func_name,
bpf_prog_type type, int& fd) {
if (funcs_.find(func_name) != funcs_.end()) {
fd = funcs_[func_name];
return StatusTuple(0);
}
uint8_t* func_start = bpf_module_->function_start(func_name);
if (!func_start)
return StatusTuple(-1, "Can't find start of function %s",
func_name.c_str());
size_t func_size = bpf_module_->function_size(func_name);
fd = bpf_prog_load(type, reinterpret_cast<struct bpf_insn*>(func_start),
func_size, bpf_module_->license(),
bpf_module_->kern_version(), nullptr,
0 // BPFModule will handle error printing
);
if (fd < 0)
return StatusTuple(-1, "Failed to load %s: %d", func_name.c_str(), fd);
bpf_module_->annotate_prog_tag(func_name, fd,
reinterpret_cast<struct bpf_insn*>(func_start),
func_size);
funcs_[func_name] = fd;
return StatusTuple(0);
}
StatusTuple BPF::unload_func(const std::string& func_name) {
auto it = funcs_.find(func_name);
if (it == funcs_.end())
return StatusTuple(0);
int res = close(it->second);
if (res != 0)
return StatusTuple(-1, "Can't close FD for %s: %d", it->first.c_str(), res);
funcs_.erase(it);
return StatusTuple(0);
}
StatusTuple BPF::check_binary_symbol(const std::string& binary_path,
const std::string& symbol,
uint64_t symbol_addr,
std::string &module_res,
uint64_t &offset_res) {
bcc_symbol output;
int res = bcc_resolve_symname(binary_path.c_str(), symbol.c_str(),
symbol_addr, -1, nullptr, &output);
if (res < 0)
return StatusTuple(
-1, "Unable to find offset for binary %s symbol %s address %lx",
binary_path.c_str(), symbol.c_str(), symbol_addr);
if (output.module) {
module_res = output.module;
::free(const_cast<char*>(output.module));
} else {
module_res = "";
}
offset_res = output.offset;
return StatusTuple(0);
}
std::string BPF::get_kprobe_event(const std::string& kernel_func,
8BD0
bpf_probe_attach_type type) {
std::string res = attach_type_prefix(type) + "_";
res += sanitize_str(kernel_func, &BPF::kprobe_event_validator);
return res;
}
BPFProgTable BPF::get_prog_table(const std::string& name) {
TableStorage::iterator it;
if (bpf_module_->table_storage().Find(Path({bpf_module_->id(), name}), it))
return BPFProgTable(it->second);
return BPFProgTable({});
}
BPFStackTable BPF::get_stack_table(const std::string& name,
bool use_debug_file,
bool check_debug_file_crc) {
TableStorage::iterator it;
if (bpf_module_->table_storage().Find(Path({bpf_module_->id(), name}), it))
return BPFStackTable(it->second, use_debug_file, check_debug_file_crc);
return BPFStackTable({}, use_debug_file, check_debug_file_crc);
}
std::string BPF::get_uprobe_event(const std::string& binary_path,
uint64_t offset, bpf_probe_attach_type type,
pid_t pid) {
std::string res = attach_type_prefix(type) + "_";
res += sanitize_str(binary_path, &BPF::uprobe_path_validator);
res += "_0x" + uint_to_hex(offset);
if (pid != -1)
res += "_" + std::to_string(pid);
return res;
}
StatusTuple BPF::detach_kprobe_event(const std::string& event,
open_probe_t& attr) {
if (attr.reader_ptr) {
perf_reader_free(attr.reader_ptr);
attr.reader_ptr = nullptr;
}
TRY2(unload_func(attr.func));
if (bpf_detach_kprobe(event.c_str()) < 0)
return StatusTuple(-1, "Unable to detach kprobe %s", event.c_str());
return StatusTuple(0);
}
StatusTuple BPF::detach_uprobe_event(const std::string& event,
open_probe_t& attr) {
if (attr.reader_ptr) {
perf_reader_free(attr.reader_ptr);
attr.reader_ptr = nullptr;
}
TRY2(unload_func(attr.func));
if (bpf_detach_uprobe(event.c_str()) < 0)
return StatusTuple(-1, "Unable to detach uprobe %s", event.c_str());
return StatusTuple(0);
}
StatusTuple BPF::detach_tracepoint_event(const std::string& tracepoint,
open_probe_t& attr) {
if (attr.reader_ptr) {
perf_reader_free(attr.reader_ptr);
attr.reader_ptr = nullptr;
}
TRY2(unload_func(attr.func));
// TODO: bpf_detach_tracepoint currently does nothing.
return StatusTuple(0);
}
StatusTuple BPF::detach_perf_event_all_cpu(open_probe_t& attr) {
bool has_error = false;
std::string err_msg;
for (const auto& it : *attr.per_cpu_fd) {
int res = bpf_close_perf_event_fd(it.second);
if (res != 0) {
has_error = true;
err_msg += "Failed to close perf event FD " + std::to_string(it.second) +
" For CPU " + std::to_string(it.first) + ": ";
err_msg += std::string(std::strerror(errno)) + "\n";
}
}
delete attr.per_cpu_fd;
TRY2(unload_func(attr.func));
if (has_error)
return StatusTuple(-1, err_msg);
return StatusTuple(0);
}
StatusTuple USDT::init() {
::USDT::Context ctx(binary_path_);
if (!ctx.loaded())
return StatusTuple(-1, "Unable to load USDT " + print_name());
auto probe = ctx.get(name_);
if (probe == nullptr)
return StatusTuple(-1, "Unable to find USDT " + print_name());
if (!probe->enable(probe_func_))
return StatusTuple(-1, "Failed to enable USDT " + print_name());
std::ostringstream stream;
if (!probe->usdt_getarg(stream))
return StatusTuple(
-1, "Unable to generate program text for USDT " + print_name());
program_text_ = ::USDT::USDT_PROGRAM_HEADER + stream.str();
addresses_.reserve(probe->num_locations());
for (size_t i = 0; i < probe->num_locations(); i++)
addresses_.emplace_back(probe->address(i));
initialized_ = true;
return StatusTuple(0);
}
} // namespace ebpf