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// Copyright 2014 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
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// See the License for the specific language governing permissions and
// limitations under the License.
#include <mach/mach.h>
#include <stdint.h>
#include <sys/types.h>
namespace crashpad {
//! \brief A Mach message option specifying that an audit trailer should be
//! delivered during a receive operation.
//! This constant is provided because the macros normally used to request this
//! behavior are cumbersome.
constexpr mach_msg_option_t kMachMessageReceiveAuditTrailer =
//! \brief Special constants used as `mach_msg_timeout_t` values.
enum : mach_msg_timeout_t {
//! \brief When passed to MachMessageDeadlineFromTimeout(), that function will
//! return #kMachMessageDeadlineNonblocking.
kMachMessageTimeoutNonblocking = 0,
//! \brief When passed to MachMessageDeadlineFromTimeout(), that function will
//! return #kMachMessageDeadlineWaitIndefinitely.
kMachMessageTimeoutWaitIndefinitely = 0xffffffff,
//! \brief The time before which a MachMessageWithDeadline() call should
//! complete.
//! A value of this type may be one of the special constants
//! #kMachMessageDeadlineNonblocking or #kMachMessageDeadlineWaitIndefinitely.
//! Any other values should be produced by calling
//! MachMessageDeadlineFromTimeout().
//! Internally, these are currently specified on the same time base as
//! ClockMonotonicNanoseconds(), although this is an implementation detail.
using MachMessageDeadline = uint64_t;
//! \brief Special constants used as \ref crashpad::MachMessageDeadline
//! "MachMessageDeadline" values.
enum : MachMessageDeadline {
//! \brief MachMessageWithDeadline() should not block at all in its operation.
kMachMessageDeadlineNonblocking = 0,
//! \brief MachMessageWithDeadline() should wait indefinitely for the
//! requested operation to complete.
kMachMessageDeadlineWaitIndefinitely = 0xffffffffffffffff,
//! \brief Computes the deadline for a specified timeout value.
//! While deadlines exist on an absolute time scale, timeouts are relative. This
//! function calculates the deadline as \a timeout_ms milliseconds after it
//! executes.
//! If \a timeout_ms is #kMachMessageDeadlineNonblocking, this function will
//! return #kMachMessageDeadlineNonblocking. If \a timeout_ms is
//! #kMachMessageTimeoutWaitIndefinitely, this function will return
//! #kMachMessageDeadlineWaitIndefinitely.
MachMessageDeadline MachMessageDeadlineFromTimeout(
mach_msg_timeout_t timeout_ms);
//! \brief Runs `mach_msg()` with a deadline, as opposed to a timeout.
//! This function is similar to `mach_msg()`, with the following differences:
//! - The `timeout` parameter has been replaced by \a deadline. The deadline
//! applies uniformly to a call that is requested to both send and receive
//! a message.
//! - The `MACH_SEND_TIMEOUT` and `MACH_RCV_TIMEOUT` bits in \a options are
//! not used. Timeouts are specified by the \a deadline argument.
//! - The `send_size` parameter has been removed. Its value is implied by
//! \a message when \a options contains `MACH_SEND_MSG`.
//! - The \a run_even_if_expired parameter has been added.
//! Like the `mach_msg()` wrapper in `libsyscall`, this function will retry
//! operations when experiencing `MACH_SEND_INTERRUPTED` and
//! `MACH_RCV_INTERRUPTED`, unless \a options contains `MACH_SEND_INTERRUPT` or
//! `MACH_RCV_INTERRUPT`. Unlike `mach_msg()`, which restarts the call with the
//! full timeout when this occurs, this function continues enforcing the
//! user-specified \a deadline.
//! Except as noted, the parameters and return value are identical to those of
//! `mach_msg()`.
//! \param[in,out] message
//! \param[in] options
//! \param[in] receive_size
//! \param[in] receive_port
//! \param[in] deadline The time by which this call should complete. If the
//! deadline is exceeded, this call will return `MACH_SEND_TIMED_OUT` or
//! \param[in] notify_port
//! \param[in] run_even_if_expired If `true`, a deadline that is expired when
//! this function is called will be treated as though a deadline of
//! #kMachMessageDeadlineNonblocking had been specified. When `false`, an
//! expired deadline will result in a `MACH_SEND_TIMED_OUT` or
//! `MACH_RCV_TIMED_OUT` return value, even if the deadline is already
//! expired when the function is called.
//! \return The return value of `mach_msg()`
mach_msg_return_t MachMessageWithDeadline(mach_msg_header_t* message,
mach_msg_option_t options,
mach_msg_size_t receive_size,
mach_port_name_t receive_port,
MachMessageDeadline deadline,
mach_port_name_t notify_port,
bool run_even_if_expired);
//! \brief Initializes a reply message for a MIG server routine based on its
//! corresponding request.
//! If a request is handled by a server routine, it may be necessary to revise
//! some of the fields set by this function, such as `msgh_size` and any fields
//! defined in a routine’s reply structure type.
//! \param[in] in_header The request message to base the reply on.
//! \param[out] out_header The reply message to initialize. \a out_header will
//! be treated as a `mig_reply_error_t*` and all of its fields will be set
//! except for `RetCode`, which must be set by SetMIGReplyError(). This
//! argument is accepted as a `mach_msg_header_t*` instead of a
//! `mig_reply_error_t*` because that is the type that callers are expected
//! to possess in the C API.
void PrepareMIGReplyFromRequest(const mach_msg_header_t* in_header,
mach_msg_header_t* out_header);
//! \brief Sets the error code in a reply message for a MIG server routine.
//! \param[in,out] out_header The reply message to operate on. \a out_header
//! will be treated as a `mig_reply_error_t*` and its `RetCode` field will
//! be set. This argument is accepted as a `mach_msg_header_t*` instead of a
//! `mig_reply_error_t*` because that is the type that callers are expected
//! to possess in the C API.
//! \param[in] error The error code to store in \a out_header.
//! \sa PrepareMIGReplyFromRequest()
void SetMIGReplyError(mach_msg_header_t* out_header, kern_return_t error);
//! \brief Returns a Mach message trailer for a message that has been received.
//! This function must only be called on Mach messages that have been received
//! via the Mach messaging interface, such as `mach_msg()`. Messages constructed
//! for sending do not contain trailers.
//! \param[in] header A pointer to a received Mach message.
//! \return A pointer to the trailer following the received Mach message’s body.
//! The contents of the trailer depend on the options provided to
//! `mach_msg()` or a similar function when the message was received.
const mach_msg_trailer_t* MachMessageTrailerFromHeader(
const mach_msg_header_t* header);
//! \brief Returns the process ID of a Mach message’s sender from its audit
//! trailer.
//! For the audit trailer to be present, the message must have been received
//! with #kMachMessageReceiveAuditTrailer or its macro equivalent specified in
//! the receive options.
//! If the kernel is the message’s sender, a process ID of `0` will be returned.
//! \param[in] trailer The trailer received with a Mach message.
//! \return The process ID of the message’s sender, or `-1` on failure with a
//! message logged. It is considered a failure for \a trailer to not contain
//! audit information.
pid_t AuditPIDFromMachMessageTrailer(const mach_msg_trailer_t* trailer);
//! \brief Destroys or deallocates a Mach port received in a Mach message.
//! This function disposes of port rights received in a Mach message. Receive
//! rights will be destroyed with `mach_port_mod_refs()`. Send and send-once
//! rights will be deallocated with `mach_port_deallocate()`.
//! \param[in] port The port to destroy or deallocate.
//! \param[in] port_right_type The right type held for \a port:
//! \return `true` on success, or `false` on failure with a message logged.
bool MachMessageDestroyReceivedPort(mach_port_t port,
mach_msg_type_name_t port_right_type);
} // namespace crashpad