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//! Provides the `#[trace_logging_provider]` macro, which allows you to define a
//! [Trace Logging Provider](https://docs.microsoft.com/en-us/windows/win32/etw/about-event-tracing#providers)
//! for use with the [Event Tracing for Windows (ETW)](https://docs.microsoft.com/en-us/windows/win32/etw/event-tracing-portal)
//! framework.
//!
//! This macro is intended for use only when targeting Windows. When targeting other platforms,
//! this macro will still work, but will generate code that does nothing.
//!
//! This framework allows applications to log schematized events, rather than textual strings.
//! ETW analysis tools can reliably identify fields within your events, and treat them as
//! strongly-typed data, rather than text strings.
//!
//! ## How to create and use an event provider
//!
//! In ETW, an _event provider_ is a software object that generates events. _Event controllers_
//! set up event logging sessions, and _event consumers_ read and interpret event data. This crate
//! focuses on enabling applications to create _event providers_.
//!
//! ## Add crate dependencies
//! Add these dependencies to your `Cargo.toml` file:
//!
//! ```text
//! [dependencies]
//! win_etw_macros = "0.1.*"
//! win_etw_provider = "0.1.*"
//! ```
//!
//! `win_etw_macros` contains the procedural macro that generates eventing code.
//! `win_etw_provider` contains library code that is called by the code that is generated by
//! `win_etw_macros`.
//!
//! ### Define the event provider and its events
//!
//! Add a trait definition to your source code and annotate it with the `#[trace_logging_provider]`
//! macro. The `#[trace_logging_provider]` macro consumes the trait definition and produces a `struct`
//! definition with the same name and the same method signatures. (The trait is _not_ available for
//! use as an ordinary trait.):
//!
//! ```rust,ignore
//! #[trace_logging_provider]
//! pub trait MyAppEvents {}
//! ```
//!
//! [Each event provider _must_ have a unique name _and_ GUID.](https://learn.microsoft.com/en-us/windows/win32/api/traceloggingprovider/nf-traceloggingprovider-tracelogging_define_provider#provider-name-and-id)
//! ETW uses this GUID to identify events that are generated by your provider. Windows contains many
//! event providers, so it is important to be able to select only the events generated by your
//! application. This GUID is also used internally by ETW to identify event metadata (field types), so
//! it is important that your GUID be unique. Otherwise, events from conflicting sources that use the
//! same GUID may be incorrectly interpreted.
//!
//! #### Specify your provider name
//!
//! Unless overridden, `#[trace_logging_provider]` uses the name of your trait definition as the name of ETW provider ("MyAppEvents" in the example aboved).
//! To specify a different name, specify the name with `#[trace_logging_provider(name = "MyCompany.MyComponent")]`.
//!
//! #### Generate a GUID for your event provider
//!
//! The `#[trace_logging_provider]` macro will generate a .NET `EventSource`-compatible name-based GUID if you do not
//! specify a `guid` parameter. The generated GUID is identical to the one generated by the following PowerShell code:
//! `[System.Diagnostics.Tracing.EventSource]::new("MyCompany.MyComponent").Guid`. The GUID is accessible from your Rust code via the associated constant named `PROVIDER_GUID` (e.g., `MyAppEvents::PROVIDER_GUID`).
//!
//! If you are not interested in using a name-based GUID, you can generate a GUID using a tool like
//! `uuidgen` (available from Visual Studio command line, or an Ubuntu shell) and specify it with
//! `#[trace_logging_provider(guid = "... your guid here ...")]`.
//!
//! #### Add events to your provider
//!
//! In the trait definition, add method signatures. Each method signature defines an _event type_.
//! The parameters of each method define the fields of the event type. Only a limited set of field
//! types are supported (enumerated below).
//!
//! ```rust,ignore
//! use win_etw_macros::trace_logging_provider;
//! #[trace_logging_provider(name = "MyCompany.MyComponent")]
//! pub trait MyAppEvents {
//! fn http_request(client_address: &SockAddr, is_https: bool, status_code: u32, status: &str);
//! fn database_connection_created(connection_id: u64, server: &str);
//! fn database_connection_closed(connection_id: u64);
//! // ...
//! }
//! ```
//!
//! ## Create an instance of the event provider
//! At initialization time (in your `fn main()`, etc.), create an instance of the event provider:
//!
//! ```rust,ignore
//! let my_app_events = MyAppEvents::new();
//! ```
//!
//! Your application should only create a single instance of each event provider, per process.
//! That is, you should create a single instance of your event provider and share it across your
//! process. Typically, an instance is stored in static variable, using a lazy / atomic assignment.
//! There are many crates and types which can support this usage pattern.
//!
//! ## Call event methods to report events
//! To report an event, call one of the methods defined on the event provider. The method will
//! call into ETW to report the event, but there is no guarantee that the event is stored or
//! forwarded; events can be dropped if event buffer resources are scarce.
//!
//! ```rust,ignore
//! my_app_events.client_connected(&"192.168.0.42:6667".parse(), false, 100, "OK");
//! ```
//!
//! # Supported field types
//! Only a limited set of field types are supported.
//!
//! * Integer primitives up to 64 bits: `i8`, `i16`, `i32`, `i64`, `u8`, `u16`, `u32`, `u64`
//! * Floating point primitives: `f32`, `f64`
//! * Architecture-dependent sizes: `usize`, `isize`.
//! * Boolean: `bool`
//! * Slices of all of the supported primitives, except for bool: `&[u8]`, `&[u16]`, etc.
//! `&[bool]` is not supported because `bool` does not have a guaranteed stable representation.
//! * Windows `[FILETIME](https://docs.microsoft.com/en-us/windows/win32/api/minwinbase/ns-minwinbase-filetime)`.
//! The type must be declared _exactly_ as `FILETIME`; type aliases or fully-qualified paths
//! (such as `winapi::shared::minwindef::FILETIME`) _will not work_. The parameter type in the
//! generated code will be `win_etw_provider::FILETIME`, which is a newtype over `u64`.
//! * `std::time::SystemTime` is supported, but it must be declared _exactly_ as `SystemTime`;
//! type aliases or fully-qualified paths (such as `std::time::SystemTime`) _will not work_.
//! * `SockAddr`, `SockAddrV4`, and `SockAddrV6` are supported. They must be declared exactly as
//! shown, not using fully-qualified names or type aliases.
//!
//! # Provider groups
//!
//! When creating an ETW provider, you can place ETW providers into _provider groups_. A provider
//! group can be enabled or disabled as a unit. To do so, specify the GUID of the provider group
//! when declaring the ETW provider. For example:
//!
//! ```no_test
//! [trace_logging_provider(
//! guid = "...", // GUID of this provider
//! provider_group_guid = "..." // GUID of the provider group that this provider belongs to
//! )]
//! pub trait MyEvents {
//! // ...
//! }
//! ```
//!
//! ## The `#[event]` attribute
//!
//! The `#[event]` atttribute allows you to control various aspects of each event type.
//! It is not necessary to use the `#[event]` attribute; if it is not specified, then
//! reasonable defaults will be chosen. You can use the `#[event]` attribute to control
//! these aspects of each event type:
//!
//! * `#[event(id = NN)]` - Specifies the event ID. All event types declared on a specific
//! event provider must have unique event IDs. See [EVENT_DESCRIPTOR]::Id.
//! * `#[event(level = NN)]` or `#[event(level = "...")]` - Specifies the event level.
//! See [EVENT_DESCRIPTOR]::Level.
//! This can either be a numeric value, or one of the following literal strings:
//! `"critical"`, `"error"`, `"warn"`, `"info"`, `"verbose"`.
//! * `#[event(opcode = NN)]` - Specifies the [EVENT_DESCRIPTOR]::Opcode field.
//! * `#[event(task = NN)` - Specifies the [EVENT_DESCRIPTOR]::Task field.
//! * `#[event(keyword = NN)` - Specifies the [EVENT_DESCRIPTOR]::Keyword field.
//!
//! [EVENT_DESCRIPTOR]: https://docs.microsoft.com/en-us/windows/win32/api/evntprov/ns-evntprov-event_descriptor
//!
//! You can use a single `#[event]` attribute with multiple values, or you can use
//! multiple `#[event]` attributes.
//!
//! # How to capture and view events
//!
//! There are a variety of tools which can be used to capture and view ETW events.
//! The simplest tool is the `TraceView` tool from the Windows SDK. Typically it is installed
//! at this path: `C:\Program Files (x86)\Windows Kits\10\bin\10.0.<xxxxx>.0\x64\traceview.exe`,
//! where `<xxxxx>` is the release number of the Windows SDK.
//!
//! Run `TraceView`, then select "File", then "Create New Log Session". Select "Manually Entered
//! GUID or Hashed Name" and enter the GUID that you have assigned to your event provider. Click OK.
//! The next dialog will prompt you to choose a source of WPP format information; select Auto
//! and click OK.
//!
//! At this point, `TraceView` should be capturing events (for your assigned GUID) and displaying
//! them in real time, regardless of which process reported the events.
//!
//! These tools can also be used to capture ETW events:
//! * [Windows Performance Recorder](https://docs.microsoft.com/en-us/windows-hardware/test/wpt/windows-performance-recorder)
//! This tool is intended for capturing system-wide event streams. It is not useful for capturing
//! events for a specific event provider.
//! * [logman](https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/logman)
//! is a command-line tool for managing events.
//! * [Tracelog](https://docs.microsoft.com/en-us/windows-hardware/drivers/devtest/tracelog)
//!
//! There are other tools, such as the Windows Performance Recorder, which can capture ETW events.
//!
//! # References
//! * [Event Tracing for Windows (ETW) Simplified](https://support.microsoft.com/en-us/help/2593157/event-tracing-for-windows-etw-simplified)
//! * [TraceLogging for Event Tracing for Windows (ETW)](https://docs.microsoft.com/en-us/windows/win32/tracelogging/trace-logging-portal)
//! * [Record and View TraceLogging Events](https://docs.microsoft.com/en-us/windows/win32/tracelogging/tracelogging-record-and-display-tracelogging-events)
//! * [TraceLoggingOptionGroup](https://docs.microsoft.com/en-us/windows/win32/api/traceloggingprovider/nf-traceloggingprovider-traceloggingoptiongroup)
//! * [Provider Traits](https://docs.microsoft.com/en-us/windows/win32/etw/provider-traits)
//! * [TRACELOGGING_DEFINE_PROVIDER macro](https://learn.microsoft.com/en-us/windows/win32/api/traceloggingprovider/nf-traceloggingprovider-tracelogging_define_provider)
// https://doc.rust-lang.org/reference/procedural-macros.html
#![deny(missing_docs)]
#![allow(clippy::too_many_arguments)]
#![allow(clippy::cognitive_complexity)]
#![allow(clippy::single_match)]
#![allow(clippy::upper_case_acronyms)]
#![allow(clippy::vec_init_then_push)]
extern crate proc_macro;
mod errors;
mod well_known_types;
use errors::{CombinedErrors, ErrorScope};
use proc_macro2::TokenStream;
use quote::{quote, quote_spanned};
use std::{collections::HashMap, iter::Extend};
use syn::spanned::Spanned;
use syn::{parse_quote, Error, Expr, ExprLit, FnArg, Ident, Lit, Token};
use uuid::Uuid;
use well_known_types::{WellKnownType, WellKnownTypes};
#[cfg(test)]
mod tests;
/// Allows you to create ETW Trace Logging Providers. See the module docs for more detailed
/// instructions for this macro.
#[proc_macro_attribute]
pub fn trace_logging_provider(
attr: proc_macro::TokenStream,
input: proc_macro::TokenStream,
) -> proc_macro::TokenStream {
// let logging_trait = parse_macro_input!(input as syn::ItemTrait);
let output = trace_logging_events_core(attr.into(), input.into());
output.into()
}
fn trace_logging_events_core(attr: TokenStream, item_tokens: TokenStream) -> TokenStream {
let mut errors: Vec<Error> = Vec::new();
let logging_trait: syn::ItemTrait = match syn::parse2(item_tokens) {
Err(e) => {
return e.to_compile_error();
}
Ok(syn::Item::Trait(t)) => t,
Ok(syn::Item::Mod(m)) => {
return Error::new_spanned(&m, "Modules are not yet supported, but thanks for asking.")
.to_compile_error();
}
Ok(unrecognized) => {
return Error::new_spanned(
&unrecognized,
"The #[trace_logging_provider] attribute cannot be used with this kind of item.",
)
.to_compile_error();
}
};
let provider_attrs: ProviderAttributes = match syn::parse2(attr) {
Ok(p) => p,
Err(e) => {
errors.push(e);
ProviderAttributes::default()
}
};
// provider_ident is the identifier used in Rust source code for the generated provider type.
let provider_ident = &logging_trait.ident;
let provider_ident_string = provider_ident.to_string();
let wk = WellKnownTypes::new();
let mut output = TokenStream::new();
let provider_metadata_ident = Ident::new(
&format!("{}_PROVIDER_METADATA", provider_ident_string),
provider_ident.span(),
);
// Create the provider metadata.
// provider_ident is the identifier used in Rust source code for the generated code.
// When writing the provider metadata, we allow the user to specify a different name to ETW.
let provider_name = provider_attrs
.provider_name
.as_ref()
.unwrap_or(&provider_ident_string);
output.extend(create_provider_metadata(
provider_name,
&provider_metadata_ident,
));
// Definitions that go inside the "impl MyProvider { ... }" block.
let mut provider_impl_items = TokenStream::new();
// To make this simple, we either require all events to be labeled
// with an event id or autogenerated.
let mut event_ids_auto_generated = true;
let mut event_id_mappings = HashMap::new();
for (method_index, method) in logging_trait
.items
.iter()
.filter_map(|item| {
if let syn::TraitItem::Method(m) = item {
Some(m)
} else {
None
}
})
.enumerate()
{
let event_index = method_index as u16;
// Check requirements for the method signature. If the requirements are not met, we
// emit an error but keep going. This allows us to report as many errors as possible in
// each build, rather than having errors "unlocked" one by one.
if method.sig.asyncness.is_some() {
errors.push(Error::new_spanned(
method,
"Async event methods are not supported.",
));
}
if method.sig.unsafety.is_some() {
errors.push(Error::new_spanned(
method,
"Event methods should not be marked unsafe.",
));
}
if !method.sig.generics.params.is_empty() {
errors.push(Error::new_spanned(
method,
"Generic event methods are not supported.",
));
}
match &method.sig.output {
syn::ReturnType::Default => {}
_ => {
errors.push(Error::new_spanned(
method,
"Event methods must not return data.",
));
}
}
if let Some(block) = method.default.as_ref() {
errors.push(Error::new_spanned(
block,
"Event methods must not contain an implementation.",
));
}
let event_name: String = method.sig.ident.to_string();
// Here we build the data descriptor array. The data descriptor array is constructed on
// the stack, and has a statically-known size. It contains pointers to data fields. The
// event metadata describes the order and type of the data pointed-to by the data
// descriptors.
//
// For self-describing events (TraceLogging), the first two items in the data descriptor
// array identify the provider metadata and the event metadata.
let mut data_descriptor_array = TokenStream::new();
// See comments in traceloggingprovider.h, around line 2300, which describe the
// encoding of the event mdata.
let mut event_metadata: Vec<Expr> = Vec::new();
event_metadata.push(parse_quote! { 0 }); // reserve space for the size (byte 0)
event_metadata.push(parse_quote! { 0 }); // reserve space for the size (byte 1)
event_metadata.push(parse_quote! { 0 }); // no extensions
append_utf8_str_chars(&mut event_metadata, &event_name);
// Some fields require running some code before building the data descriptors, so we
// collect statements here.
let mut statements = TokenStream::new();
// Each parameter (except for &self) becomes an event field.
let mut found_receiver = false;
// sig is the function signature for the function that we will generate for this event.
let mut sig = method.sig.clone();
for param in sig.inputs.iter_mut() {
let param_span = param.span();
match param {
FnArg::Receiver(_) => {
errors.push(Error::new_spanned(param, "Event methods should not provide any receiver arguments (&self, &mut self, etc.)."));
found_receiver = true;
}
FnArg::Typed(param_typed) => {
let mut event_attr: Option<syn::Attribute> = None;
param_typed.attrs.retain(|a| {
if a.path == parse_quote!(event) {
event_attr = Some(a.clone());
false
} else if a.path == parse_quote!(doc) {
true
} else {
errors.push(Error::new_spanned(
a,
"This attribute is not permitted on event fields.",
));
true
}
});
let param_name: &Ident = match &*param_typed.pat {
syn::Pat::Ident(ref name) => &name.ident,
_ => {
errors.push(Error::new(
param.span(),
"Only ordinary parameter patterns are supported on event methods.",
));
continue;
}
};
if parse_event_field(
&mut errors,
&wk,
event_attr.as_ref(),
param_span,
param_name,
&mut param_typed.ty,
&mut data_descriptor_array,
&mut event_metadata,
&mut statements,
)
.is_err()
{
errors.push(Error::new_spanned(
¶m,
"This type is not supported for event parameters.",
));
}
}
}
}
// We require that every function declare a '&self' receiver parameter.
if !found_receiver {
sig.inputs.insert(0, parse_quote!(&self));
}
// Insert the "options" argument.
sig.inputs.insert(
1,
parse_quote!(options: core::option::Option<&::win_etw_provider::EventOptions>),
);
// Now that we have processed all parameters ("fields"), we can finish constructing
// the per-event metadata.
let event_metadata_len = event_metadata.len();
if event_metadata_len > 0xffff {
errors.push(Error::new(
method.span(),
"Event metadata is too large to encode; reduce the complexity of this event.",
));
continue;
}
let event_metadata_len_b0 = (event_metadata_len & 0xff) as u8;
let event_metadata_len_b1 = (event_metadata_len >> 8) as u8;
event_metadata[0] = parse_quote! { #event_metadata_len_b0 };
event_metadata[1] = parse_quote! { #event_metadata_len_b1 };
let event_attrs = parse_event_attributes(&mut errors, &method.sig.ident, &method.attrs);
// Generate the event descriptor for this event.
// This is a static variable. The name is exactly the name of the event.
let event_level = event_attrs.level;
let event_opcode = event_attrs.opcode;
let event_task = event_attrs.task;
let potential_event_id = event_attrs.event_id;
let event_keyword = event_attrs
.keyword
.as_ref()
.cloned()
.unwrap_or_else(|| parse_quote!(0));
// We use the first entry to see if we have user provided IDs
// or we are generating one.
if event_index == 0 {
event_ids_auto_generated = potential_event_id.is_none();
}
// We have some events with user provided id and some without.
if event_ids_auto_generated != potential_event_id.is_none() {
errors.push(Error::new(
method.span(),
"Event ids must be set for all events, or for none.",
));
}
let event_id = potential_event_id.unwrap_or(event_index);
// Only care about #[event(id = #)] types so we don't get
// confusing messages when forget to add an id for some
// event.
if potential_event_id.is_some() {
let identifier = method.sig.ident.to_string();
if let Some(previous) = event_id_mappings.get(&event_id) {
errors.push(Error::new(
method.span(),
format!(
"Event id {} has already been defined on {}.",
event_id, previous
),
));
}
event_id_mappings.insert(event_id, identifier);
}
// an expression which generates EventDescriptor
let event_descriptor = quote! {
::win_etw_provider::EventDescriptor {
id: #event_id,
version: 0,
channel: 11,
level: #event_level,
opcode: #event_opcode,
task: #event_task,
keyword: #event_keyword,
};
};
let event_attrs_method_attrs = &event_attrs.method_attrs;
// Generate the `${name}_is_enabled` function for this event.
// We do not use ident_suffix() because this is not a private identifier.
let event_is_enabled_name = Ident::new(
&format!("{}_is_enabled", method.sig.ident),
method.sig.ident.span(),
);
// Build the method that implements this event.
provider_impl_items.extend(quote!{
#( #event_attrs_method_attrs )*
#[cfg_attr(not(target_os = "windows"), allow(unused_variables))]
pub #sig
{
#[cfg(target_os = "windows")]
{
use ::win_etw_provider::EventDataDescriptor;
// This places the EVENT_METADATA into a read-only linker section, properly
// ordered with respect to TRACE_LOGGING_METADATA and other related sections.
#[link_section = ".rdata$etw1"]
#[used]
static EVENT_METADATA: [u8; #event_metadata_len] = [ #( #event_metadata, )* ];
let mut event_descriptor: ::win_etw_provider::EventDescriptor = #event_descriptor;
if let Some(opts) = options {
if let Some(level) = opts.level {
event_descriptor.level = level;
}
}
#statements
let data_descriptors = [
EventDataDescriptor::for_provider_metadata(&#provider_metadata_ident[..]),
EventDataDescriptor::for_event_metadata(&EVENT_METADATA[..]),
#data_descriptor_array
];
::win_etw_provider::Provider::write(&self.provider,
options,
&event_descriptor,
&data_descriptors,
);
}
}
pub fn #event_is_enabled_name(&self, level: ::core::option::Option<::win_etw_provider::Level>) -> bool {
#[cfg(target_os = "windows")]
{
let mut event_descriptor: ::win_etw_provider::EventDescriptor = #event_descriptor;
if let Some(level) = level {
event_descriptor.level = level;
}
::win_etw_provider::Provider::is_event_enabled(
&self.provider,
&event_descriptor)
}
#[cfg(not(target_os = "windows"))]
{
false
}
}
});
}
// We propagate the visibility of the trait definition to the structure definition.
let vis = logging_trait.vis.clone();
let provider_guid = match provider_attrs.uuid {
Some(uuid) => uuid,
None => etw_event_source_guid(provider_name),
};
let provider_guid_const = uuid_to_expr(&provider_guid);
// If the input item has doc attributes, then carry them over to the output type.
let doc_path: syn::Path = parse_quote!(doc);
let provider_doc_attrs = logging_trait
.attrs
.iter()
.filter(|a| a.path == doc_path)
.collect::<Vec<_>>();
// Build a code fragment that registers the provider traits.
let register_traits: TokenStream = create_register_provider_traits(
&provider_name,
provider_attrs.provider_group_guid.as_ref(),
);
output.extend(quote! {
#( #provider_doc_attrs )*
#vis struct #provider_ident {
provider: ::core::option::Option<::win_etw_provider::EtwProvider>,
}
impl #provider_ident {
/// Creates (registers) a new instance of this provider. If registration fails,
/// returns a "null" provider. This prevents problems with event logging from
/// disrupting the normal operation of applications.
///
/// On non-Windows platforms, this function always returns a null provider.
///
/// Creating an event source is a costly operation, because it requires contacting the
/// event manager, allocating event buffers, potentially receiving callbacks from
/// event consumers, etc. Applications should only create event sources during process
/// initialization, and should always reuse them, never re-creating them.
pub fn new() -> Self {
let provider = match ::win_etw_provider::EtwProvider::new(&Self::PROVIDER_GUID) {
Ok(mut provider) => {
#[cfg(target_os = "windows")]
{
#register_traits
}
Some(provider)
}
Err(_) => None,
};
Self { provider }
}
/// Creates (registers) a new instance of this provider. If registration fails, then
/// this method returns a "null" provider.
///
/// On non-Windows platforms, this function always returns `Ok`, containing a null
/// provider.
///
/// Creating an event source is a costly operation, because it requires contacting the
/// event manager, allocating event buffers, potentially receiving callbacks from
/// event consumers, etc. Applications should only create event sources during process
/// initialization, and should always reuse them, never re-creating them.
pub fn new_err() -> ::core::result::Result<Self, ::win_etw_provider::Error> {
Ok(Self {
provider: Some(::win_etw_provider::EtwProvider::new(&Self::PROVIDER_GUID)?),
})
}
/// Creates a new "null" instance of the provider. All events written to this provider
/// are discarded.
pub fn null() -> Self {
Self { provider: None }
}
#[allow(unused_variable)]
pub const PROVIDER_GUID: ::win_etw_provider::GUID = #provider_guid_const;
pub const PROVIDER_NAME: &'static str = #provider_name;
}
// We intentionally generate identifiers that are not snake-case.
#[allow(non_snake_case)]
impl #provider_ident {
#provider_impl_items
}
});
output.extend(errors.into_iter().map(|e| e.to_compile_error()));
output
}
/// Creates a fragment of code (statements) which will register the
/// provider traits for this provider.
//
// See https://docs.microsoft.com/en-us/windows/win32/etw/provider-traits
fn create_register_provider_traits(
provider_name: &str,
provider_group_guid: Option<&Uuid>,
) -> TokenStream {
let mut traits_bytes: Vec<u8> = Vec::new();
traits_bytes.push(0); // reserve space for TraitsSize (u16)
traits_bytes.push(0);
traits_bytes.extend_from_slice(provider_name.as_bytes());
traits_bytes.push(0);
if let Some(provider_group_guid) = provider_group_guid {
// Add trait for provider guid
let provider_guid_trait_offset = traits_bytes.len();
traits_bytes.push(0); // reserve space for TraitSize (u16)
traits_bytes.push(0);
traits_bytes.push(ETW_PROVIDER_TRAIT_TYPE_GROUP);
traits_bytes.extend_from_slice(&provider_group_guid.to_bytes_le());
let provider_guid_trait_len = traits_bytes.len() - provider_guid_trait_offset;
// Set TraitSize (u16)
traits_bytes[provider_guid_trait_offset] = provider_guid_trait_len as u8;
traits_bytes[provider_guid_trait_offset + 1] = (provider_guid_trait_len >> 8) as u8;
}
// Set TraitsSize (u16)
traits_bytes[0] = traits_bytes.len() as u8;
traits_bytes[1] = (traits_bytes.len() >> 8) as u8;
let traits_bytes_len = traits_bytes.len();
quote! {
static PROVIDER_TRAITS: [u8; #traits_bytes_len] = [ #(#traits_bytes),* ];
// We ignore the Result from calling set_provider_traits.
// There is no good way to report it.
let _ = provider.set_provider_traits(&PROVIDER_TRAITS);
}
}
fn err_spanned<T: quote::ToTokens>(item: &T, msg: &str) -> TokenStream {
Error::new_spanned(item, msg).to_compile_error()
}
// `provider_name` is not necessarily the same as the identifier used in source code.
// It can be overridden using `#[trace_logging_provider(name = "some_name_here")]`.
fn create_provider_metadata(provider_name: &str, provider_metadata_ident: &Ident) -> TokenStream {
let mut provider_metadata: Vec<u8> = Vec::new();
let provider_metadata_len = 2 + provider_name.len() + 1;
if provider_metadata_len > 0xffff {
return err_spanned(&provider_name, "The provider name is too long.");
}
provider_metadata.push((provider_metadata_len & 0xff) as u8);
provider_metadata.push((provider_metadata_len >> 8) as u8);
provider_metadata.extend_from_slice(provider_name.as_bytes());
provider_metadata.push(0);
quote! {
#[link_section = ".rdata$etw2"]
#[used]
#[allow(non_upper_case_globals)]
#[cfg(target_os = "windows")]
static #provider_metadata_ident: [u8; #provider_metadata_len] = [
#(
#provider_metadata,
)*
];
}
}
fn append_utf8_str_chars(output: &mut Vec<Expr>, s: &str) {
for &b in s.as_bytes().iter() {
output.push(parse_quote! { #b });
}
// Add the NUL byte at the end.
output.push(parse_quote! { 0 });
}
struct UnsupportedField;
/// Parses one event field. Event fields are declared as function parameters.
///
/// * `event_metadata`: This builds the static [u8; N] array that contains the metadata for this
/// event. It can contain literals, symbolic expressions, etc.
fn parse_event_field(
errors: &mut Vec<Error>,
well_known_types: &WellKnownTypes,
event_attr: Option<&syn::Attribute>,
field_span: proc_macro2::Span,
field_name: &Ident,
field_ty: &mut syn::Type,
data_descriptor_array: &mut TokenStream,
event_metadata: &mut Vec<syn::Expr>,
statements: &mut TokenStream,
) -> Result<(), UnsupportedField> {
// Write the field metadata.
// // FieldMetadata:
// struct FieldMetadata // Variable-length pseudo-structure, byte-aligned, tightly-packed.
// {
// char Name[]; // UTF-8 nul-terminated field name
// UINT8 InType; // Values from the TlgIn enumeration.
// UINT8 OutType; // TlgOut enumeration. Only present if (InType & 128) == 128.
// UINT8 Extension[]; // Only present if OutType is present and (OutType & 128) == 128. Read until you hit a byte with high bit unset.
// UINT16 ValueCount; // Only present if (InType & CountMask) == Ccount.
// UINT16 TypeInfoSize; // Only present if (InType & CountMask) == Custom.
// char TypeInfo[TypeInfoSize]; // Only present if (InType & CountMask) == Custom.
// };
let param_name_string = field_name.to_string();
append_utf8_str_chars(event_metadata, ¶m_name_string);
// We will append more data to event_metadata, below.
// The user can annotate fields with #[event(...)] in order to specify output formats.
let mut output_hex = false;
if let Some(event_attr) = event_attr {
match event_attr.parse_meta() {
Ok(syn::Meta::List(list)) => {
for item in list.nested.iter() {
match item {
syn::NestedMeta::Meta(syn::Meta::NameValue(syn::MetaNameValue {
path,
lit,
..
})) => {
if path.is_ident("output") {
match &lit {
Lit::Str(lit) => {
let output_string = lit.value();
match output_string.as_str() {
"hex" => {
output_hex = true;
}
_ => {
errors.push(Error::new_spanned(
path,
"Output format is not recognized.",
));
}
}
}
_ => errors.push(Error::new_spanned(
path,
"This metadata is expected to be a string.",
)),
}
} else {
errors.push(Error::new_spanned(
path,
"This metadata key is not recognized.",
));
}
}
_ => errors.push(Error::new_spanned(
item,
"This metadata item is not recognized.",
)),
}
}
}
Ok(_) => errors.push(Error::new_spanned(
event_attr,
"This metadata is not recognized.",
)),
Err(e) => {
errors.push(e);
}
}
}
let mut field_metadata_intype: Expr;
let mut field_metadata_out_type: Option<Expr> = None;
if let Some(t) = well_known_types.find(&*field_ty) {
field_metadata_intype = if let Some(in_type_expr) = t.opts.in_type_expr.as_ref() {
in_type_expr.clone()
} else {
let in_type: u8 = t.in_type.bits();
parse_quote!(#in_type)
};
if let Some(out_type) = t.opts.out_type {
let out_type: u8 = out_type.bits();
field_metadata_out_type = Some(parse_quote!(#out_type));
} else {
field_metadata_out_type = None;
}
if let Some(r) = t.opts.replacement_type.as_ref() {
*field_ty = r.clone();
}
match t.code {
WellKnownType::ref_str => {
// We encode &str as COUNTEDANSISTRING (so that we do not need
// a NUL-terminated string) and marking its output type as UTF-8.
// This uses two EVENT_DATA_DESCRIPTOR slots.
let field_len = ident_suffix(field_name, "len");
statements.extend(quote_spanned! {
field_span =>
let #field_len: u16 = #field_name.len() as u16;
});
data_descriptor_array.extend(quote! {
EventDataDescriptor::from(&#field_len),
EventDataDescriptor::from(#field_name),
});
}
WellKnownType::u16str => {
// UCS-2 string without NUL terminator.
let field_len = ident_suffix(field_name, "len");
statements.extend(quote! {
let #field_len: usize = #field_name.len(); // length in code units
// Since we're recording this as COUNTEDUNICODESTRING, we
// want the length in bytes of the string, excluding the NUL.
// Which is easy, because there is no NUL.
let #field_len: u16 = (#field_len * 2).min(0xffff) as u16;
});
data_descriptor_array.extend(quote! {
EventDataDescriptor::from(&#field_len),
EventDataDescriptor::from(#field_name),
});
}
WellKnownType::u16cstr => {
// UCS-2 string without NUL terminator.
let field_len = ident_suffix(field_name, "len");
statements.extend(quote! {
let #field_len: usize = #field_name.len(); // length in code units
// Since we're recording this as COUNTEDUNICODESTRING, we
// want the length in bytes of the string, excluding the NUL.
let #field_len: u16 = (#field_len * 2).min(0xffff) as u16;
});
data_descriptor_array.extend(quote! {
EventDataDescriptor::from(&#field_len),
EventDataDescriptor::from(#field_name),
});
}
WellKnownType::osstr => {
let field_len = ident_suffix(field_name, "len");
let field_desc = ident_suffix(field_name, "desc");
let field_u16cstring = ident_suffix(field_name, "u16cstring");
let field_u16cstr = ident_suffix(field_name, "u16cstr");
statements.extend(quote! {
let #field_desc: EventDataDescriptor;
let #field_len: u16;
let #field_u16cstring: ::win_etw_provider::types::U16CString;
let #field_u16cstr: &::win_etw_provider::types::U16CStr;
match ::win_etw_provider::types::U16CString::from_os_str(#field_name) {
Ok(s) => {
#field_u16cstring = s;
#field_u16cstr = #field_u16cstring.as_ref();
#field_desc = EventDataDescriptor::from(#field_u16cstr);
#field_len = (#field_u16cstr.len() as u16 * 2); // compute length in bytes
}
Err(_) => {
#field_desc = EventDataDescriptor::empty();
#field_len = 0;
}
}
});
data_descriptor_array.extend(quote! {
EventDataDescriptor::from(&#field_len),
#field_desc,
});
}
WellKnownType::SocketAddrV4 => {
// We cannot simply pass a copy of std::net::SocketAddrV4 to ETW because it does
// not have a guaranteed memory layout. So we convert it to
// win_etw_provider::SocketAddrV4, which does.
let field_len = ident_suffix(field_name, "len");
statements.extend(quote_spanned! {
field_span =>
let #field_name = ::win_etw_provider::SocketAddrV4::from(#field_name);
let #field_len: u16 = (::core::mem::size_of::<::win_etw_provider::SocketAddrV4>()) as u16;
});
data_descriptor_array.extend(quote! {
EventDataDescriptor::from(&#field_len),
EventDataDescriptor::from(&#field_name),
});
}
WellKnownType::SocketAddrV6 => {
// We cannot simply pass a copy of std::net::SocketAddrV6 to ETW because it does
// not have a guaranteed memory layout. So we convert it to
// win_etw_provider::SocketAddrV6, which does.
let field_len = ident_suffix(field_name, "len");
statements.extend(quote_spanned! {
field_span =>
let #field_name = ::win_etw_provider::SocketAddrV6::from(#field_name);
let #field_len: u16 = (::core::mem::size_of::<::win_etw_provider::SocketAddrV6>()) as u16;
});
data_descriptor_array.extend(quote_spanned! {
field_span =>
EventDataDescriptor::from(&#field_len),
EventDataDescriptor::from(&#field_name),
});
}
WellKnownType::SocketAddr => {
let field_desc = ident_suffix(field_name, "desc");
let field_v4 = ident_suffix(field_name, "v4");
let field_v6 = ident_suffix(field_name, "v6");
let field_len_ident = ident_suffix(field_name, "len");
statements.extend(quote_spanned! {
field_span =>
let #field_v4;
let #field_v6;
let #field_len_ident;
let #field_desc;
match #field_name {
::std::net::SocketAddr::V4(ref address_v4) => {
#field_v4 = ::win_etw_provider::SocketAddrV4::from(address_v4);
#field_len_ident = ::core::mem::size_of::<::win_etw_provider::SocketAddrV4>() as u16;
#field_desc = EventDataDescriptor::from(&#field_v4);
}
::std::net::SocketAddr::V6(ref address_v6) => {
#field_v6 = ::win_etw_provider::SocketAddrV6::from(address_v6);
#field_len_ident = ::core::mem::size_of::<::win_etw_provider::SocketAddrV6>() as u16;
#field_desc = EventDataDescriptor::from(&#field_v6);
}
}
});
data_descriptor_array.extend(quote_spanned! {
field_span =>
EventDataDescriptor::from(&#field_len_ident),
#field_desc,
});
}
WellKnownType::SystemTime => {
// If the SystemTime value cannot be converted to a FILETIME, then the data
// descriptor for this field will be empty, rather than pointing to an invalid
// or incorrect time value.
statements.extend(quote_spanned!{
field_span =>
let #field_name = <::win_etw_provider::FILETIME as ::core::convert::TryFrom<::std::time::SystemTime>>
::try_from(#field_name);
});
data_descriptor_array.extend(quote_spanned! {
field_span =>
match &#field_name {
Ok(ref t) => EventDataDescriptor::from(&t.0),
Err(_) => EventDataDescriptor::empty(),
}
});
}
WellKnownType::FILETIME => {
data_descriptor_array.extend(quote_spanned! {
field_span =>
EventDataDescriptor::from(&#field_name.0),
});
}
WellKnownType::bool => {
statements.extend(quote_spanned! {
field_span =>
let #field_name: i8 = #field_name as i8;
});
data_descriptor_array.extend(quote! {
EventDataDescriptor::from(&#field_name),
});
}
_ => {
if t.is_ref {
data_descriptor_array.extend(quote_spanned! {
field_span =>
EventDataDescriptor::from(#field_name),
});
} else {
data_descriptor_array.extend(quote_spanned! {
field_span =>
EventDataDescriptor::from(&#field_name),
});
}
}
}
} else {
match &*field_ty {
syn::Type::Reference(ref_ty) => {
match &*ref_ty.elem {
syn::Type::Slice(slice_ty) => {
if let Some(t) = well_known_types.find(&slice_ty.elem) {
if !t.primitive {
return Err(UnsupportedField);
}
// Slices are encoded using two data descriptors.
// The first is for the length field, the second for the data.
let field_len_ident = ident_suffix(field_name, "len");
statements.extend(quote_spanned! {
field_span =>
let #field_name = &#field_name[..#field_name.len().min(0xffff)];
let #field_len_ident: u16 = #field_name.len() as u16;
});
data_descriptor_array.extend(quote! {
EventDataDescriptor::from(&#field_len_ident),
EventDataDescriptor::from(#field_name),
});
// 0x40 is VCOUNT flag
let in_type_u8 = t.in_type.bits();
field_metadata_intype = parse_quote!(#in_type_u8);
field_metadata_intype = parse_quote!(#field_metadata_intype | ::win_etw_provider::metadata::InFlag::VCOUNT_FLAG.bits());
} else {
return Err(UnsupportedField);
}
}
_ => {
return Err(UnsupportedField);
}
}
}
_ => {
return Err(UnsupportedField);
}
}
}
if output_hex {
let hex: Expr = parse_quote!(::win_etw_provider::metadata::OutFlag::HEX.bits());
field_metadata_out_type = Some(if let Some(out_type) = field_metadata_out_type {
parse_quote!(#out_type | #hex)
} else {
hex
});
}
if let Some(out_type) = field_metadata_out_type {
field_metadata_intype = parse_quote!(#field_metadata_intype | ::win_etw_provider::metadata::InFlag::CHAIN_FLAG.bits());
event_metadata.push(field_metadata_intype);
event_metadata.push(out_type);
} else {
event_metadata.push(field_metadata_intype);
}
Ok(())
}
/// Represents the "attribute" parameter of the `#[trace_logging_provider]` proc macro.
#[derive(Default, Debug)]
struct ProviderAttributes {
uuid: Option<Uuid>,
provider_name: Option<String>,
provider_group_guid: Option<Uuid>,
}
impl syn::parse::Parse for ProviderAttributes {
fn parse(stream: syn::parse::ParseStream) -> syn::Result<Self> {
let mut errors = CombinedErrors::default();
let mut uuid_opt = None;
let items: syn::punctuated::Punctuated<syn::Meta, Token![,]> =
stream.parse_terminated(syn::Meta::parse)?;
let mut provider_group_guid: Option<Uuid> = None;
let parse_guid_value = |lit: &Lit, scope: &mut ErrorScope| -> Uuid {
if let syn::Lit::Str(s) = lit {
let guid_str = s.value();
if let Ok(value) = guid_str.parse::<Uuid>() {
if value == Uuid::nil() {
scope.msg("The GUID cannot be the NIL (all-zeroes) GUID.");
}
value
} else {
scope.msg("The attribute value is required to be a valid GUID.");
Uuid::nil()
}
} else {
scope.msg("The attribute value is required to be a GUID in string form.");
Uuid::nil()
}
};
let mut provider_name = None;
for item in items.iter() {
errors.scope(item.span(), |scope| {
match item {
syn::Meta::NameValue(syn::MetaNameValue { path, lit, .. }) => {
if path.is_ident("guid") {
let uuid = parse_guid_value(lit, scope);
if uuid_opt.is_some() {
scope.msg(
"The 'guid' attribute key cannot be specified more than once.",
);
} else {
uuid_opt = Some(uuid);
}
} else if path.is_ident("name") {
if let syn::Lit::Str(s) = lit {
if provider_name.is_none() {
provider_name = Some(s.value());
} else {
scope.msg("The 'name' attribute can only be specified once.");
}
} else {
scope.msg("The 'name' attribute key requires a string value.");
}
} else if path.is_ident("provider_group_guid") {
let uuid = parse_guid_value(lit, scope);
if provider_group_guid.is_some() {
scope.msg("The 'provider_group_guid' attribute key cannot be specified more than once.");
} else {
provider_group_guid = Some(uuid);
}
} else {
scope.msg("Unrecognized attribute key.");
}
}
syn::Meta::Path(path) if path.is_ident("static_mode") => {
// eprintln!("Found 'static'");
}
_ => {
// eprintln!("item: {:#?}", item);
scope.msg("Unrecognized attribute item.");
}
}
Ok(())
});
}
errors.into_result(ProviderAttributes {
uuid: uuid_opt,
provider_name,
provider_group_guid,
})
}
}
const ETW_EVENT_SOURCE_NAMESPACE: Uuid = uuid::uuid!("482c2db2-c390-47c8-87f8-1a15bfc130fb");
/// Generates a Uuid from a provider name using the same algorithm as .NET's EventSource class.
/// Many tools convert a provider name to a GUID using this algorithm.
fn etw_event_source_guid(provider_name: &str) -> Uuid {
use sha1_smol::Sha1;
let provider_bytes: Vec<u8> = provider_name
.to_uppercase()
.encode_utf16()
.flat_map(|x| x.to_be_bytes())
.collect();
let mut hasher = Sha1::new();
hasher.update(ETW_EVENT_SOURCE_NAMESPACE.as_bytes());
hasher.update(&provider_bytes);
let mut bytes = [0; 16];
bytes.copy_from_slice(&hasher.digest().bytes()[..16]);
// .NET EventSource reads the bytes from the SHA-1 hash for the first 3 fields
// as little-endian, but does not set the "variant (aka type)" to the "Microsoft" value which
// indicates little-endian in a RFC4122-conforming UUID. The "variant" field
// ends up being the "random" value copied from the from the SHA-1 hash, instead.
uuid::Builder::from_bytes_le(bytes)
.with_version(uuid::Version::Sha1)
.into_uuid()
}
fn uuid_to_expr(uuid: &Uuid) -> syn::Expr {
let bytes: &[u8; 16] = uuid.as_bytes();
let data1: u32 = ((bytes[0] as u32) << 24)
| ((bytes[1] as u32) << 16)
| ((bytes[2] as u32) << 8)
| (bytes[3] as u32);
let data2: u16 = ((bytes[4] as u16) << 8) | (bytes[5] as u16);
let data3: u16 = ((bytes[6] as u16) << 8) | (bytes[7] as u16);
let data4_0 = bytes[8];
let data4_1 = bytes[9];
let data4_2 = bytes[10];
let data4_3 = bytes[11];
let data4_4 = bytes[12];
let data4_5 = bytes[13];
let data4_6 = bytes[14];
let data4_7 = bytes[15];
parse_quote! {
::win_etw_provider::GUID {
data1: #data1,
data2: #data2,
data3: #data3,
data4: [
#data4_0,
#data4_1,
#data4_2,
#data4_3,
#data4_4,
#data4_5,
#data4_6,
#data4_7,
]
}
}
}
struct EventAttributes {
level: syn::Expr,
opcode: syn::Expr,
task: syn::Expr,
keyword: Option<syn::Expr>,
event_id: Option<u16>,
method_attrs: Vec<syn::Attribute>,
}
fn parse_event_attributes(
errors: &mut Vec<Error>,
method_ident: &Ident,
input_method_attrs: &[syn::Attribute],
) -> EventAttributes {
let mut level: Expr = parse_quote!(::win_etw_provider::Level::VERBOSE);
let mut opcode: Expr = parse_quote!(0);
let mut task: Expr = parse_quote!(0);
let mut keyword: Option<Expr> = None;
// I am not aware of how to convert from Expr to actual value
// so going to handle this here.
let mut event_id: Option<u16> = None;
let mut method_attrs: Vec<syn::Attribute> = Vec::new();
let mut event_already_has_doc = false;
let enable_default_event_doc = false;
for attr in input_method_attrs.iter() {
if attr.path == parse_quote!(doc) {
method_attrs.push(attr.clone());
event_already_has_doc = true;
} else if attr.path.is_ident("event") {
// The #[event] attribute lets the application specify the level, opcode, task,
// keyword, etc.
match attr.parse_meta() {
Ok(syn::Meta::List(list)) => {
for item in list.nested.iter() {
match item {
syn::NestedMeta::Meta(syn::Meta::NameValue(syn::MetaNameValue {
path,
lit,
..
})) => {
if path.is_ident("level") {
match lit {
Lit::Str(lit_str) => {
let level_ident = match lit_str.value().as_str() {
"critical" => quote!(CRITICAL),
"error" => quote!(ERROR),
"warn" => quote!(WARN),
"info" => quote!(INFO),
"verbose" => quote!(VERBOSE),
_ => {
errors.push(Error::new_spanned(item, "The value specified for 'level' is not a valid string."));
quote!(VERBOSE)
}
};
level = parse_quote!(::win_etw_provider::Level::#level_ident);
}
Lit::Int(_) => {
level = parse_quote!(::win_etw_provider::Level(#lit));
}
_ => {
errors.push(Error::new_spanned(item, "The value specified for 'level' is not recognized."));
}
}
} else if path.is_ident("opcode") {
opcode = Expr::Lit(ExprLit {
lit: lit.clone(),
attrs: Vec::new(),
});
} else if path.is_ident("task") {
task = Expr::Lit(ExprLit {
lit: lit.clone(),
attrs: Vec::new(),
});
} else if path.is_ident("keyword") {
if keyword.is_some() {
errors.push(Error::new(attr.span(), "The 'keyword' attribute cannot be specified more than once."));
} else {
keyword = Some(Expr::Lit(ExprLit {
lit: lit.clone(),
attrs: Vec::new(),
}));
}
} else if path.is_ident("id") {
if event_id.is_some() {
errors.push(Error::new(
lit.span(),
"Event id has already been defined.".to_string(),
));
} else if let Lit::Int(lit_int) = lit {
if let Ok(int_value) = lit_int.base10_parse() {
event_id = Some(int_value);
} else {
errors.push(Error::new(
lit.span(),
"Event id must be a u16.".to_string(),
));
}
} else {
errors.push(Error::new(
lit.span(),
"Event id must be a u16.".to_string(),
));
}
} else {
errors
.push(Error::new_spanned(item, "Unrecognized attribute."));
}
}
_ => {
errors.push(Error::new_spanned(item, "Unrecognized attribute."));
}
}
}
}
Ok(_) => {
errors.push(Error::new_spanned(
attr,
"The form of the #[event] attribute is invalid. \
It should be: #[event(name = \"value\", name2 = \"value2\", ...)].",
));
}
Err(e) => {
errors.push(Error::new(
attr.span(),
format!("Unrecognized attribute: {}", e),
));
}
}
} else {
errors.push(Error::new_spanned(
attr,
"The only attributes allowed on event methods are #[doc] and #[event(...)] attributes.",
));
}
}
if !event_already_has_doc && enable_default_event_doc {
let method_doc = format!("Writes the `{}` event to the ETW log stream.", method_ident);
method_attrs.push(parse_quote!( #![doc = #method_doc] ));
}
EventAttributes {
method_attrs,
level,
opcode,
task,
event_id,
keyword,
}
}
/// The separator we use to build dynamic identifiers, based on existing identifiers.
/// Ideally, we would use a string that will not cause collisions with user-provided
/// identifiers. Rust supports non-ASCII identifiers, which would allow us to
/// use something like `U+0394 GREEK CAPITAL LETTER DELTA`, but this is an unstable
/// feature.
///
/// Instead, we use "__". Idiomatic identifiers should not contain "__" because this
/// does not meet Rust's definition of a snake-case name. So we add use this, and add
/// `#[allow(non_snake_case)]` to our generated code.
const IDENT_SEPARATOR: &str = "__";
/// Builds a new identifier, based on an existing identifier.
fn ident_suffix(ident: &Ident, suffix: &str) -> Ident {
Ident::new(
&format!("{}{}{}", ident, IDENT_SEPARATOR, suffix),
ident.span(),
)
}
const ETW_PROVIDER_TRAIT_TYPE_GROUP: u8 = 1;