crashpad/util/mach/bootstrap.cc
Mark Mentovai ba24acb86c ios: Split bootstrap out from mach_extensions
mach_extensions is sensible on iOS, but bootstrap is not available
outside of macOS. To allow mach_extensions to be used cleanly on iOS,
the bootstrap code is moved into its own macOS-specific file.

Bug: crashpad:31
Change-Id: I7bf9d5194253b563954a1e55fbf67a16f686e8ff
Reviewed-on: https://chromium-review.googlesource.com/c/crashpad/crashpad/+/2154529
Reviewed-by: Justin Cohen <justincohen@chromium.org>
Commit-Queue: Mark Mentovai <mark@chromium.org>
2020-04-17 20:54:47 +00:00

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// Copyright 2020 The Crashpad Authors. All rights reserved.
//
// 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 "util/mach/bootstrap.h"
#include <mach/mach.h>
#include <servers/bootstrap.h>
#include "base/mac/mach_logging.h"
namespace {
// This forms the internal implementation for BootstrapCheckIn() and
// BootstrapLookUp(), which follow the same logic aside from the routine called
// and the right type returned.
struct BootstrapCheckInTraits {
using Type = base::mac::ScopedMachReceiveRight;
static kern_return_t Call(mach_port_t bootstrap_port,
const char* service_name,
mach_port_t* service_port) {
return bootstrap_check_in(bootstrap_port, service_name, service_port);
}
static constexpr char kName[] = "bootstrap_check_in";
};
constexpr char BootstrapCheckInTraits::kName[];
struct BootstrapLookUpTraits {
using Type = base::mac::ScopedMachSendRight;
static kern_return_t Call(mach_port_t bootstrap_port,
const char* service_name,
mach_port_t* service_port) {
return bootstrap_look_up(bootstrap_port, service_name, service_port);
}
static constexpr char kName[] = "bootstrap_look_up";
};
constexpr char BootstrapLookUpTraits::kName[];
template <typename Traits>
typename Traits::Type BootstrapCheckInOrLookUp(
const std::string& service_name) {
// bootstrap_check_in() and bootstrap_look_up() silently truncate service
// names longer than BOOTSTRAP_MAX_NAME_LEN. This check ensures that the name
// will not be truncated.
if (service_name.size() >= BOOTSTRAP_MAX_NAME_LEN) {
LOG(ERROR) << Traits::kName << " " << service_name << ": name too long";
return typename Traits::Type(MACH_PORT_NULL);
}
mach_port_t service_port;
kern_return_t kr =
Traits::Call(bootstrap_port, service_name.c_str(), &service_port);
if (kr != BOOTSTRAP_SUCCESS) {
BOOTSTRAP_LOG(ERROR, kr) << Traits::kName << " " << service_name;
service_port = MACH_PORT_NULL;
}
return typename Traits::Type(service_port);
}
} // namespace
namespace crashpad {
base::mac::ScopedMachReceiveRight BootstrapCheckIn(
const std::string& service_name) {
return BootstrapCheckInOrLookUp<BootstrapCheckInTraits>(service_name);
}
base::mac::ScopedMachSendRight BootstrapLookUp(
const std::string& service_name) {
base::mac::ScopedMachSendRight send(
BootstrapCheckInOrLookUp<BootstrapLookUpTraits>(service_name));
// Its possible to race the bootstrap server when the receive right
// corresponding to the looked-up send right is destroyed immediately before
// the bootstrap_look_up() call. If the bootstrap server believes that
// |service_name| is still registered before processing the port-destroyed
// notification sent to it by the kernel, it will respond to a
// bootstrap_look_up() request with a send right that has become a dead name,
// which will be returned to the bootstrap_look_up() caller, translated into
// the callers IPC port name space, as the special MACH_PORT_DEAD port name.
// Check for that and return MACH_PORT_NULL in its place, as though the
// bootstrap server had fully processed the port-destroyed notification before
// responding to bootstrap_look_up().
if (send.get() == MACH_PORT_DEAD) {
LOG(ERROR) << "bootstrap_look_up " << service_name << ": service is dead";
send.reset();
}
return send;
}
base::mac::ScopedMachSendRight SystemCrashReporterHandler() {
return BootstrapLookUp("com.apple.ReportCrash");
}
} // namespace crashpad