294 lines
10 KiB
C++
294 lines
10 KiB
C++
// Copyright 2014 The Crashpad Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "util/mach/mach_message.h"
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#include <Availability.h>
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#include <limits>
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#include "base/logging.h"
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#include "base/mac/mach_logging.h"
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#include "build/build_config.h"
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#include "util/misc/clock.h"
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#include "util/misc/implicit_cast.h"
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#if BUILDFLAG(IS_MAC)
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#include <bsm/libbsm.h>
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#endif // BUILDFLAG(IS_MAC)
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namespace crashpad {
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namespace {
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constexpr int kNanosecondsPerMillisecond = 1E6;
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// TimerRunning() determines whether |deadline| has passed. If |deadline| is
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// kMachMessageDeadlineWaitIndefinitely, |*timeout_options| is set to
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// MACH_MSG_OPTION_NONE, |*remaining_ms| is set to MACH_MSG_TIMEOUT_NONE, and
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// this function returns true. When used with mach_msg(), this will cause
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// indefinite waiting. In any other case, |*timeout_options| is set to
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// MACH_SEND_TIMEOUT | MACH_RCV_TIMEOUT, so mach_msg() will enforce a timeout
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// specified by |*remaining_ms|. If |deadline| is in the future, |*remaining_ms|
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// is set to the number of milliseconds remaining, which will always be a
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// positive value, and this function returns true. If |deadline| is
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// kMachMessageDeadlineNonblocking (indicating that no timer is in effect),
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// |*remaining_ms| is set to zero and this function returns true. Otherwise,
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// this function sets |*remaining_ms| to zero and returns false.
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bool TimerRunning(uint64_t deadline,
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mach_msg_timeout_t* remaining_ms,
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mach_msg_option_t* timeout_options) {
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if (deadline == kMachMessageDeadlineWaitIndefinitely) {
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*remaining_ms = MACH_MSG_TIMEOUT_NONE;
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*timeout_options = MACH_MSG_OPTION_NONE;
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return true;
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}
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*timeout_options = MACH_SEND_TIMEOUT | MACH_RCV_TIMEOUT;
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if (deadline == kMachMessageDeadlineNonblocking) {
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*remaining_ms = 0;
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return true;
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}
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uint64_t now = ClockMonotonicNanoseconds();
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if (now >= deadline) {
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*remaining_ms = 0;
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} else {
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uint64_t remaining = deadline - now;
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// Round to the nearest millisecond, taking care not to overflow.
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constexpr int kHalfMillisecondInNanoseconds =
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kNanosecondsPerMillisecond / 2;
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if (remaining <=
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std::numeric_limits<uint64_t>::max() - kHalfMillisecondInNanoseconds) {
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*remaining_ms = (remaining + kHalfMillisecondInNanoseconds) /
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kNanosecondsPerMillisecond;
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} else {
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*remaining_ms = remaining / kNanosecondsPerMillisecond;
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}
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}
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return *remaining_ms != 0;
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}
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// This is an internal implementation detail of MachMessageWithDeadline(). It
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// determines whether |deadline| has expired, and what timeout value and
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// timeout-related options to pass to mach_msg() based on the value of
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// |deadline|. mach_msg() will only be called if TimerRunning() returns true or
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// if run_even_if_expired is true.
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mach_msg_return_t MachMessageWithDeadlineInternal(mach_msg_header_t* message,
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mach_msg_option_t options,
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mach_msg_size_t receive_size,
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mach_port_name_t receive_port,
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MachMessageDeadline deadline,
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mach_port_name_t notify_port,
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bool run_even_if_expired) {
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mach_msg_timeout_t remaining_ms;
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mach_msg_option_t timeout_options;
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if (!TimerRunning(deadline, &remaining_ms, &timeout_options) &&
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!run_even_if_expired) {
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// Simulate the timed-out return values from mach_msg().
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if (options & MACH_SEND_MSG) {
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return MACH_SEND_TIMED_OUT;
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}
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if (options & MACH_RCV_MSG) {
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return MACH_RCV_TIMED_OUT;
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}
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return MACH_MSG_SUCCESS;
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}
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// Turn off the passed-in timeout bits and replace them with the ones from
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// TimerRunning(). Get the send_size value from message->msgh_size if sending
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// a message.
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return mach_msg(
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message,
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(options & ~(MACH_SEND_TIMEOUT | MACH_RCV_TIMEOUT)) | timeout_options,
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options & MACH_SEND_MSG ? message->msgh_size : 0,
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receive_size,
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receive_port,
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remaining_ms,
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notify_port);
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}
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} // namespace
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MachMessageDeadline MachMessageDeadlineFromTimeout(
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mach_msg_timeout_t timeout_ms) {
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switch (timeout_ms) {
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case kMachMessageTimeoutNonblocking:
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return kMachMessageDeadlineNonblocking;
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case kMachMessageTimeoutWaitIndefinitely:
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return kMachMessageDeadlineWaitIndefinitely;
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default:
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return ClockMonotonicNanoseconds() +
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implicit_cast<uint64_t>(timeout_ms) * kNanosecondsPerMillisecond;
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}
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}
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mach_msg_return_t MachMessageWithDeadline(mach_msg_header_t* message,
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mach_msg_option_t options,
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mach_msg_size_t receive_size,
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mach_port_name_t receive_port,
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MachMessageDeadline deadline,
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mach_port_name_t notify_port,
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bool run_even_if_expired) {
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// mach_msg() actaully does return MACH_MSG_SUCCESS when not asked to send or
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// receive anything. See 10.9.5 xnu-1504.15.3/osfmk/ipc/mach_msg.c
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// mach_msg_overwrite_trap().
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mach_msg_return_t mr = MACH_MSG_SUCCESS;
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// Break up the send and receive into separate operations, so that the timeout
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// can be recomputed from the deadline for each. Otherwise, the computed
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// timeout will apply individually to the send and then to the receive, and
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// the desired deadline could be exceeded.
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//
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// During sends, always set MACH_SEND_INTERRUPT, and during receives, always
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// set MACH_RCV_INTERRUPT. If the caller didn’t specify these options, the
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// calls will be retried with a recomputed deadline. If these bits weren’t
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// set, the libsyscall wrapper (10.9.5
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// xnu-2422.115.4/libsyscall/mach/mach_msg.c mach_msg() would restart
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// interrupted calls with the original timeout value computed from the
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// deadline, which would no longer correspond to the actual deadline. If the
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// caller did specify these bits, don’t restart anything, because the caller
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// wants to be notified of any interrupted calls.
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if (options & MACH_SEND_MSG) {
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do {
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mr = MachMessageWithDeadlineInternal(
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message,
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(options & ~MACH_RCV_MSG) | MACH_SEND_INTERRUPT,
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0,
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MACH_PORT_NULL,
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deadline,
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notify_port,
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run_even_if_expired);
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} while (mr == MACH_SEND_INTERRUPTED && !(options & MACH_SEND_INTERRUPT));
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if (mr != MACH_MSG_SUCCESS) {
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return mr;
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}
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}
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if (options & MACH_RCV_MSG) {
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do {
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mr = MachMessageWithDeadlineInternal(
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message,
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(options & ~MACH_SEND_MSG) | MACH_RCV_INTERRUPT,
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receive_size,
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receive_port,
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deadline,
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notify_port,
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run_even_if_expired);
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} while (mr == MACH_RCV_INTERRUPTED && !(options & MACH_RCV_INTERRUPT));
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}
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return mr;
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}
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void PrepareMIGReplyFromRequest(const mach_msg_header_t* in_header,
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mach_msg_header_t* out_header) {
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out_header->msgh_bits =
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MACH_MSGH_BITS(MACH_MSGH_BITS_REMOTE(in_header->msgh_bits), 0);
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out_header->msgh_size = sizeof(mig_reply_error_t);
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out_header->msgh_remote_port = in_header->msgh_remote_port;
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out_header->msgh_local_port = MACH_PORT_NULL;
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out_header->msgh_reserved = 0;
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out_header->msgh_id = in_header->msgh_id + 100;
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reinterpret_cast<mig_reply_error_t*>(out_header)->NDR = NDR_record;
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}
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void SetMIGReplyError(mach_msg_header_t* out_header, kern_return_t error) {
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reinterpret_cast<mig_reply_error_t*>(out_header)->RetCode = error;
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}
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const mach_msg_trailer_t* MachMessageTrailerFromHeader(
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const mach_msg_header_t* header) {
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vm_address_t header_address = reinterpret_cast<vm_address_t>(header);
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vm_address_t trailer_address = header_address + round_msg(header->msgh_size);
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return reinterpret_cast<const mach_msg_trailer_t*>(trailer_address);
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}
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bool MachMessageDestroyReceivedPort(mach_port_t port,
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mach_msg_type_name_t port_right_type) {
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// This implements a subset of 10.10.5
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// xnu-2782.40.9/libsyscall/mach/mach_msg.c mach_msg_destroy_port() that deals
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// only with port rights that can be received in Mach messages.
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switch (port_right_type) {
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case MACH_MSG_TYPE_PORT_RECEIVE: {
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kern_return_t kr = mach_port_mod_refs(
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mach_task_self(), port, MACH_PORT_RIGHT_RECEIVE, -1);
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if (kr != KERN_SUCCESS) {
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MACH_LOG(ERROR, kr) << "mach_port_mod_refs";
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return false;
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}
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return true;
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}
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case MACH_MSG_TYPE_PORT_SEND:
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case MACH_MSG_TYPE_PORT_SEND_ONCE: {
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kern_return_t kr = mach_port_deallocate(mach_task_self(), port);
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if (kr != KERN_SUCCESS) {
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MACH_LOG(ERROR, kr) << "mach_port_deallocate";
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return false;
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}
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return true;
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}
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default: {
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LOG(ERROR) << "unexpected port right type " << port_right_type;
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return false;
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}
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}
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}
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#if BUILDFLAG(IS_MAC)
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pid_t AuditPIDFromMachMessageTrailer(const mach_msg_trailer_t* trailer) {
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if (trailer->msgh_trailer_type != MACH_MSG_TRAILER_FORMAT_0) {
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LOG(ERROR) << "unexpected msgh_trailer_type " << trailer->msgh_trailer_type;
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return -1;
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}
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if (trailer->msgh_trailer_size <
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REQUESTED_TRAILER_SIZE(kMachMessageReceiveAuditTrailer)) {
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LOG(ERROR) << "small msgh_trailer_size " << trailer->msgh_trailer_size;
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return -1;
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}
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const mach_msg_audit_trailer_t* audit_trailer =
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reinterpret_cast<const mach_msg_audit_trailer_t*>(trailer);
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#if __MAC_OS_X_VERSION_MIN_REQUIRED < __MAC_10_8
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pid_t audit_pid;
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audit_token_to_au32(audit_trailer->msgh_audit,
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nullptr,
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nullptr,
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nullptr,
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nullptr,
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nullptr,
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&audit_pid,
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nullptr,
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nullptr);
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#else
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pid_t audit_pid = audit_token_to_pid(audit_trailer->msgh_audit);
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#endif
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return audit_pid;
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}
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#endif // BUILDFLAG(IS_MAC)
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} // namespace crashpad
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