209 lines
9.2 KiB
C++
209 lines
9.2 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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#ifndef CRASHPAD_UTIL_MACH_MACH_MESSAGE_H_
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#define CRASHPAD_UTIL_MACH_MACH_MESSAGE_H_
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#include <mach/mach.h>
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#include <stdint.h>
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#include <sys/types.h>
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#include "build/build_config.h"
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namespace crashpad {
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//! \brief A Mach message option specifying that an audit trailer should be
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//! delivered during a receive operation.
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//!
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//! This constant is provided because the macros normally used to request this
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//! behavior are cumbersome.
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constexpr mach_msg_option_t kMachMessageReceiveAuditTrailer =
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MACH_RCV_TRAILER_TYPE(MACH_MSG_TRAILER_FORMAT_0) |
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MACH_RCV_TRAILER_ELEMENTS(MACH_RCV_TRAILER_AUDIT);
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//! \brief Special constants used as `mach_msg_timeout_t` values.
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enum : mach_msg_timeout_t {
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//! \brief When passed to MachMessageDeadlineFromTimeout(), that function will
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//! return #kMachMessageDeadlineNonblocking.
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kMachMessageTimeoutNonblocking = 0,
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//! \brief When passed to MachMessageDeadlineFromTimeout(), that function will
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//! return #kMachMessageDeadlineWaitIndefinitely.
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kMachMessageTimeoutWaitIndefinitely = 0xffffffff,
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};
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//! \brief The time before which a MachMessageWithDeadline() call should
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//! complete.
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//!
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//! A value of this type may be one of the special constants
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//! #kMachMessageDeadlineNonblocking or #kMachMessageDeadlineWaitIndefinitely.
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//! Any other values should be produced by calling
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//! MachMessageDeadlineFromTimeout().
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//!
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//! Internally, these are currently specified on the same time base as
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//! ClockMonotonicNanoseconds(), although this is an implementation detail.
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using MachMessageDeadline = uint64_t;
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//! \brief Special constants used as \ref crashpad::MachMessageDeadline
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//! "MachMessageDeadline" values.
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enum : MachMessageDeadline {
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//! \brief MachMessageWithDeadline() should not block at all in its operation.
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kMachMessageDeadlineNonblocking = 0,
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//! \brief MachMessageWithDeadline() should wait indefinitely for the
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//! requested operation to complete.
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kMachMessageDeadlineWaitIndefinitely = 0xffffffffffffffff,
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};
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//! \brief Computes the deadline for a specified timeout value.
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//!
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//! While deadlines exist on an absolute time scale, timeouts are relative. This
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//! function calculates the deadline as \a timeout_ms milliseconds after it
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//! executes.
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//!
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//! If \a timeout_ms is #kMachMessageDeadlineNonblocking, this function will
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//! return #kMachMessageDeadlineNonblocking. If \a timeout_ms is
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//! #kMachMessageTimeoutWaitIndefinitely, this function will return
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//! #kMachMessageDeadlineWaitIndefinitely.
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MachMessageDeadline MachMessageDeadlineFromTimeout(
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mach_msg_timeout_t timeout_ms);
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//! \brief Runs `mach_msg()` with a deadline, as opposed to a timeout.
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//!
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//! This function is similar to `mach_msg()`, with the following differences:
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//! - The `timeout` parameter has been replaced by \a deadline. The deadline
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//! applies uniformly to a call that is requested to both send and receive
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//! a message.
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//! - The `MACH_SEND_TIMEOUT` and `MACH_RCV_TIMEOUT` bits in \a options are
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//! not used. Timeouts are specified by the \a deadline argument.
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//! - The `send_size` parameter has been removed. Its value is implied by
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//! \a message when \a options contains `MACH_SEND_MSG`.
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//! - The \a run_even_if_expired parameter has been added.
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//!
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//! Like the `mach_msg()` wrapper in `libsyscall`, this function will retry
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//! operations when experiencing `MACH_SEND_INTERRUPTED` and
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//! `MACH_RCV_INTERRUPTED`, unless \a options contains `MACH_SEND_INTERRUPT` or
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//! `MACH_RCV_INTERRUPT`. Unlike `mach_msg()`, which restarts the call with the
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//! full timeout when this occurs, this function continues enforcing the
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//! user-specified \a deadline.
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//!
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//! Except as noted, the parameters and return value are identical to those of
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//! `mach_msg()`.
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//!
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//! \param[in,out] message
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//! \param[in] options
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//! \param[in] receive_size
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//! \param[in] receive_port
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//! \param[in] deadline The time by which this call should complete. If the
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//! deadline is exceeded, this call will return `MACH_SEND_TIMED_OUT` or
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//! `MACH_RCV_TIMED_OUT`.
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//! \param[in] notify_port
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//! \param[in] run_even_if_expired If `true`, a deadline that is expired when
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//! this function is called will be treated as though a deadline of
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//! #kMachMessageDeadlineNonblocking had been specified. When `false`, an
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//! expired deadline will result in a `MACH_SEND_TIMED_OUT` or
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//! `MACH_RCV_TIMED_OUT` return value, even if the deadline is already
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//! expired when the function is called.
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//!
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//! \return The return value of `mach_msg()`
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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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//! \brief Initializes a reply message for a MIG server routine based on its
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//! corresponding request.
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//!
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//! If a request is handled by a server routine, it may be necessary to revise
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//! some of the fields set by this function, such as `msgh_size` and any fields
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//! defined in a routine’s reply structure type.
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//!
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//! \param[in] in_header The request message to base the reply on.
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//! \param[out] out_header The reply message to initialize. \a out_header will
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//! be treated as a `mig_reply_error_t*` and all of its fields will be set
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//! except for `RetCode`, which must be set by SetMIGReplyError(). This
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//! argument is accepted as a `mach_msg_header_t*` instead of a
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//! `mig_reply_error_t*` because that is the type that callers are expected
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//! to possess in the C API.
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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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//! \brief Sets the error code in a reply message for a MIG server routine.
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//!
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//! \param[in,out] out_header The reply message to operate on. \a out_header
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//! will be treated as a `mig_reply_error_t*` and its `RetCode` field will
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//! be set. This argument is accepted as a `mach_msg_header_t*` instead of a
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//! `mig_reply_error_t*` because that is the type that callers are expected
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//! to possess in the C API.
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//! \param[in] error The error code to store in \a out_header.
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//!
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//! \sa PrepareMIGReplyFromRequest()
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void SetMIGReplyError(mach_msg_header_t* out_header, kern_return_t error);
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//! \brief Returns a Mach message trailer for a message that has been received.
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//!
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//! This function must only be called on Mach messages that have been received
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//! via the Mach messaging interface, such as `mach_msg()`. Messages constructed
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//! for sending do not contain trailers.
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//!
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//! \param[in] header A pointer to a received Mach message.
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//!
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//! \return A pointer to the trailer following the received Mach message’s body.
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//! The contents of the trailer depend on the options provided to
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//! `mach_msg()` or a similar function when the message was received.
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const mach_msg_trailer_t* MachMessageTrailerFromHeader(
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const mach_msg_header_t* header);
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//! \brief Destroys or deallocates a Mach port received in a Mach message.
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//!
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//! This function disposes of port rights received in a Mach message. Receive
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//! rights will be destroyed with `mach_port_mod_refs()`. Send and send-once
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//! rights will be deallocated with `mach_port_deallocate()`.
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//!
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//! \param[in] port The port to destroy or deallocate.
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//! \param[in] port_right_type The right type held for \a port:
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//! `MACH_MSG_TYPE_PORT_RECEIVE`, `MACH_MSG_TYPE_PORT_SEND`, or
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//! `MACH_MSG_TYPE_PORT_SEND_ONCE`.
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//!
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//! \return `true` on success, or `false` on failure with a message logged.
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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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#if BUILDFLAG(IS_MAC) || DOXYGEN
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//! \brief Returns the process ID of a Mach message’s sender from its audit
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//! trailer.
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//!
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//! For the audit trailer to be present, the message must have been received
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//! with #kMachMessageReceiveAuditTrailer or its macro equivalent specified in
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//! the receive options.
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//!
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//! If the kernel is the message’s sender, a process ID of `0` will be returned.
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//!
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//! \param[in] trailer The trailer received with a Mach message.
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//!
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//! \return The process ID of the message’s sender, or `-1` on failure with a
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//! message logged. It is considered a failure for \a trailer to not contain
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//! audit information.
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pid_t AuditPIDFromMachMessageTrailer(const mach_msg_trailer_t* trailer);
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#endif // BUILDFLAG(IS_MAC)
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} // namespace crashpad
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#endif // CRASHPAD_UTIL_MACH_MACH_MESSAGE_H_
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