Merge pull request #350 from dave-tucker/monorepo

Bring aya-log into aya, creating a Monorepo

.cargo/config

@@ -1,5 +1,7 @@
 [alias]
 xtask = "run --package xtask --"
+build-bpfel = "build -Zbuild-std=core --target=bpfel-unknown-none"
+build-bpfeb = "build -Zbuild-std=core --target=bpfeb-unknown-none"
 
 [target.armv7-unknown-linux-gnueabi]
 linker = "arm-linux-gnueabi-gcc"

.github/workflows/build-aya-bpf.yml

@@ -31,59 +31,19 @@ jobs:
       - uses: actions-rs/toolchain@v1
         with:
           toolchain: nightly
+          components: rust-src
           override: true
 
       - uses: Swatinem/rust-cache@v1
 
       - name: Prereqs
-        run: cargo install cross --git https://github.com/cross-rs/cross
+        run: cargo install bpf-linker
 
       - name: Build
         env:
           CARGO_CFG_BPF_TARGET_ARCH: ${{ matrix.arch }}
         run: |
-          pushd bpf
+          cargo build-bpfel -p aya-bpf --verbose
-          cargo build --workspace --exclude aya-bpf-macros --verbose
+          cargo build-bpfeb -p aya-bpf --verbose
-          popd
+          cargo build-bpfel -p aya-log-ebpf --verbose
-
+          cargo build-bpfeb -p aya-log-ebpf --verbose
-      - name: Run tests
-        env:
-          CARGO_CFG_BPF_TARGET_ARCH: ${{ matrix.arch }}
-        run: |
-          pushd bpf
-          cargo test --workspace --exclude aya-bpf-macros --verbose
-          popd
-
-  build-macros:
-    strategy:
-      matrix:
-        arch:
-          - x86_64-unknown-linux-gnu
-          - aarch64-unknown-linux-gnu
-          - armv7-unknown-linux-gnueabi
-          - riscv64gc-unknown-none-elf
-    runs-on: ubuntu-20.04
-    steps:
-      - uses: actions/checkout@v2
-
-      - uses: actions-rs/toolchain@v1
-        with:
-          toolchain: nightly
-          override: true
-
-      - uses: Swatinem/rust-cache@v1
-
-      - name: Prereqs
-        run: cargo install cross --git https://github.com/cross-rs/cross
-
-      - name: Build bpf macros
-        run: |
-          pushd bpf
-          cross build -p aya-bpf-macros --verbose
-          popd
-
-      - name: Test bpf macros
-        run: |
-          pushd bpf
-          RUST_BACKTRACE=full cross test -p aya-bpf-macros --verbose
-          popd

.github/workflows/build-aya.yml

@@ -21,19 +21,28 @@ jobs:
           - x86_64-unknown-linux-gnu
           - aarch64-unknown-linux-gnu
           - armv7-unknown-linux-gnueabi
-          - riscv64gc-unknown-none-elf
+          - riscv64gc-unknown-linux-gnu
     runs-on: ubuntu-20.04
     steps:
       - uses: actions/checkout@v2
+
+      - uses: actions-rs/toolchain@v1
+        with:
+          toolchain: stable
+          override: true
+
       - uses: Swatinem/rust-cache@v1
       - name: Prereqs
         run: cargo install cross --git https://github.com/cross-rs/cross
 
       - name: Build
-        run: cross build --verbose
+        run: cross build --verbose --target ${{matrix.arch}}
 
       - name: Run test
-        run: RUST_BACKTRACE=full cross test --verbose
+        env:
+          RUST_BACKTRACE: full
+        run: |
+          cross test --verbose --target ${{matrix.arch}}
 
   test:
     runs-on: ubuntu-20.04
@@ -60,12 +69,10 @@ jobs:
           sudo apt-get -qy install linux-tools-common qemu-system-x86 cloud-image-utils openssh-client libelf-dev gcc-multilib
           cargo install bpf-linker
 
-
       - name: Lint integration tests
         run: |
           cargo xtask build-integration-test-ebpf --libbpf-dir ./libbpf
           cargo clippy -p integration-test -- --deny warnings
-          cargo clippy -p integration-test-macros -- --deny warnings
 
       - name: Run integration tests
         run: |

.github/workflows/lint.yml

@@ -30,22 +30,11 @@ jobs:
       - name: Check formatting
         run: |
           cargo fmt --all -- --check
-          (cd bpf && cargo fmt --all -- --check)
-          (cd test/integration-ebpf && cargo fmt --all -- --check)
 
       - name: Run clippy
         run: |
-          cargo clippy -p aya -- --deny warnings
+          cargo clippy --workspace --exclude integration-test -- --deny warnings
-          cargo clippy -p aya-gen -- --deny warnings
-          cargo clippy -p xtask -- --deny warnings
-          (cd bpf && cargo clippy -p aya-bpf -- --deny warnings)
-          (cd test/integration-ebpf && cargo clippy -- --deny warnings)
 
       - name: Run miri
-        env:
-          MIRIFLAGS: -Zmiri-disable-stacked-borrows
         run: |
           cargo miri test --all-targets
-          pushd bpf
-          cargo miri test
-          popd

.vim/coc-settings.json

@@ -1,4 +1,4 @@
 {
-  "rust-analyzer.linkedProjects": ["Cargo.toml", "bpf/Cargo.toml", "test/integration-ebpf/Cargo.toml"],
+  "rust-analyzer.checkOnSave.allTargets": false,
-  "rust-analyzer.checkOnSave.allTargets": false
+  "rust-analyzer.checkOnSave.command": "clippy"
 }

.vscode/settings.json

@@ -1,4 +1,4 @@
 {
-  "rust-analyzer.linkedProjects": ["Cargo.toml", "bpf/Cargo.toml", "test/integration-ebpf/Cargo.toml"],
+  "rust-analyzer.checkOnSave.allTargets": false,
-  "rust-analyzer.checkOnSave.allTargets": false
+  "rust-analyzer.checkOnSave.command": "clippy"
 }

Cargo.toml

@@ -1,3 +1,22 @@
 [workspace]
-members = ["aya", "aya-gen", "test/integration-test", "test/integration-test-macros", "xtask"]
+members = [
-default-members = ["aya", "aya-gen"]
+    "aya", "aya-gen", "aya-log", "aya-log-common", "test/integration-test", "test/integration-test-macros", "xtask",
+    # macros
+    "aya-bpf-macros", "aya-log-ebpf-macros",
+    # ebpf crates
+    "bpf/aya-bpf", "bpf/aya-bpf-bindings", "bpf/aya-log-ebpf", "test/integration-ebpf"
+]
+default-members = ["aya", "aya-gen", "aya-log", "aya-bpf-macros", "aya-log-ebpf-macros"]
+
+[profile.dev]
+panic = "abort"
+
+[profile.release]
+panic = "abort"
+
+[profile.dev.package.integration-ebpf]
+opt-level = 2
+overflow-checks = false
+
+[profile.release.package.integration-ebpf]
+debug = 2

aya-bpf-macros/Cargo.toml

@@ -13,4 +13,4 @@ quote = "1.0"
 syn = {version = "1.0", features = ["full"]}
 
 [dev-dependencies]
-aya-bpf = { path = "../aya-bpf" }
+aya-bpf = { path = "../bpf/aya-bpf" }

aya-log-common/Cargo.toml

@@ -0,0 +1,20 @@
+[package]
+name = "aya-log-common"
+version = "0.1.11-dev.0"
+description = "A logging library for eBPF programs."
+keywords = ["ebpf", "bpf", "log", "logging"]
+license = "MIT OR Apache-2.0"
+authors = ["The Aya Contributors"]
+repository = "https://github.com/aya-rs/aya-log"
+documentation = "https://docs.rs/aya-log"
+edition = "2018"
+
+[features]
+default = []
+userspace = [ "aya" ]
+
+[dependencies]
+aya = { path = "../aya", version = "0.11.0", optional=true }
+
+[lib]
+path = "src/lib.rs"

aya-log-common/release.toml

@@ -0,0 +1 @@
+shared-version = true

aya-log-common/src/lib.rs

@@ -0,0 +1,185 @@
+#![no_std]
+
+use core::{cmp, mem, ptr};
+
+pub const LOG_BUF_CAPACITY: usize = 8192;
+
+pub const LOG_FIELDS: usize = 7;
+
+#[repr(usize)]
+#[derive(Copy, Clone, Eq, PartialEq, Debug, Hash)]
+pub enum Level {
+    /// The "error" level.
+    ///
+    /// Designates very serious errors.
+    Error = 1,
+    /// The "warn" level.
+    ///
+    /// Designates hazardous situations.
+    Warn,
+    /// The "info" level.
+    ///
+    /// Designates useful information.
+    Info,
+    /// The "debug" level.
+    ///
+    /// Designates lower priority information.
+    Debug,
+    /// The "trace" level.
+    ///
+    /// Designates very low priority, often extremely verbose, information.
+    Trace,
+}
+
+#[repr(usize)]
+#[derive(Copy, Clone, Debug)]
+pub enum RecordField {
+    Target = 1,
+    Level,
+    Module,
+    File,
+    Line,
+    NumArgs,
+    Log,
+}
+
+#[repr(usize)]
+#[derive(Copy, Clone, Debug)]
+pub enum ArgType {
+    I8,
+    I16,
+    I32,
+    I64,
+    I128,
+    Isize,
+
+    U8,
+    U16,
+    U32,
+    U64,
+    U128,
+    Usize,
+
+    F32,
+    F64,
+
+    Str,
+}
+
+#[cfg(feature = "userspace")]
+mod userspace {
+    use super::*;
+
+    unsafe impl aya::Pod for RecordField {}
+    unsafe impl aya::Pod for ArgType {}
+}
+
+struct TagLenValue<'a, T> {
+    tag: T,
+    value: &'a [u8],
+}
+
+impl<'a, T> TagLenValue<'a, T>
+where
+    T: Copy,
+{
+    #[inline(always)]
+    pub(crate) fn new(tag: T, value: &'a [u8]) -> TagLenValue<'a, T> {
+        TagLenValue { tag, value }
+    }
+
+    pub(crate) fn write(&self, mut buf: &mut [u8]) -> Result<usize, ()> {
+        let size = mem::size_of::<T>() + mem::size_of::<usize>() + self.value.len();
+        let remaining = cmp::min(buf.len(), LOG_BUF_CAPACITY);
+        // Check if the size doesn't exceed the buffer bounds.
+        if size > remaining {
+            return Err(());
+        }
+
+        unsafe { ptr::write_unaligned(buf.as_mut_ptr() as *mut _, self.tag) };
+        buf = &mut buf[mem::size_of::<T>()..];
+
+        unsafe { ptr::write_unaligned(buf.as_mut_ptr() as *mut _, self.value.len()) };
+        buf = &mut buf[mem::size_of::<usize>()..];
+
+        let len = cmp::min(buf.len(), self.value.len());
+        // The verifier isn't happy with `len` being unbounded, so compare it
+        // with `LOG_BUF_CAPACITY`.
+        if len > LOG_BUF_CAPACITY {
+            return Err(());
+        }
+        buf[..len].copy_from_slice(&self.value[..len]);
+        Ok(size)
+    }
+}
+
+pub trait WriteToBuf {
+    #[allow(clippy::result_unit_err)]
+    fn write(&self, buf: &mut [u8]) -> Result<usize, ()>;
+}
+
+macro_rules! impl_write_to_buf {
+    ($type:ident, $arg_type:expr) => {
+        impl WriteToBuf for $type {
+            fn write(&self, buf: &mut [u8]) -> Result<usize, ()> {
+                TagLenValue::<ArgType>::new($arg_type, &self.to_ne_bytes()).write(buf)
+            }
+        }
+    };
+}
+
+impl_write_to_buf!(i8, ArgType::I8);
+impl_write_to_buf!(i16, ArgType::I16);
+impl_write_to_buf!(i32, ArgType::I32);
+impl_write_to_buf!(i64, ArgType::I64);
+impl_write_to_buf!(i128, ArgType::I128);
+impl_write_to_buf!(isize, ArgType::Isize);
+
+impl_write_to_buf!(u8, ArgType::U8);
+impl_write_to_buf!(u16, ArgType::U16);
+impl_write_to_buf!(u32, ArgType::U32);
+impl_write_to_buf!(u64, ArgType::U64);
+impl_write_to_buf!(u128, ArgType::U128);
+impl_write_to_buf!(usize, ArgType::Usize);
+
+impl_write_to_buf!(f32, ArgType::F32);
+impl_write_to_buf!(f64, ArgType::F64);
+
+impl WriteToBuf for str {
+    fn write(&self, buf: &mut [u8]) -> Result<usize, ()> {
+        TagLenValue::<ArgType>::new(ArgType::Str, self.as_bytes()).write(buf)
+    }
+}
+
+#[allow(clippy::result_unit_err)]
+#[doc(hidden)]
+#[inline(always)]
+pub fn write_record_header(
+    buf: &mut [u8],
+    target: &str,
+    level: Level,
+    module: &str,
+    file: &str,
+    line: u32,
+    num_args: usize,
+) -> Result<usize, ()> {
+    let mut size = 0;
+    for attr in [
+        TagLenValue::<RecordField>::new(RecordField::Target, target.as_bytes()),
+        TagLenValue::<RecordField>::new(RecordField::Level, &(level as usize).to_ne_bytes()),
+        TagLenValue::<RecordField>::new(RecordField::Module, module.as_bytes()),
+        TagLenValue::<RecordField>::new(RecordField::File, file.as_bytes()),
+        TagLenValue::<RecordField>::new(RecordField::Line, &line.to_ne_bytes()),
+        TagLenValue::<RecordField>::new(RecordField::NumArgs, &num_args.to_ne_bytes()),
+    ] {
+        size += attr.write(&mut buf[size..])?;
+    }
+
+    Ok(size)
+}
+
+#[allow(clippy::result_unit_err)]
+#[doc(hidden)]
+pub fn write_record_message(buf: &mut [u8], msg: &str) -> Result<usize, ()> {
+    TagLenValue::<RecordField>::new(RecordField::Log, msg.as_bytes()).write(buf)
+}

aya-log-ebpf-macros/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "aya-log-ebpf-macros"
+version = "0.1.0"
+edition = "2018"
+
+[dependencies]
+proc-macro2 = "1.0"
+quote = "1.0"
+syn = "1.0"
+
+[lib]
+proc-macro = true

aya-log-ebpf-macros/src/expand.rs

@@ -0,0 +1,189 @@
+use proc_macro2::TokenStream;
+use quote::quote;
+use syn::{
+    parse::{Parse, ParseStream},
+    punctuated::Punctuated,
+    Error, Expr, LitStr, Result, Token,
+};
+
+pub(crate) struct LogArgs {
+    pub(crate) ctx: Expr,
+    pub(crate) target: Option<Expr>,
+    pub(crate) level: Option<Expr>,
+    pub(crate) format_string: LitStr,
+    pub(crate) formatting_args: Option<Punctuated<Expr, Token![,]>>,
+}
+
+mod kw {
+    syn::custom_keyword!(target);
+}
+
+impl Parse for LogArgs {
+    fn parse(input: ParseStream) -> Result<Self> {
+        let ctx: Expr = input.parse()?;
+        input.parse::<Token![,]>()?;
+
+        // Parse `target: &str`, which is an optional argument.
+        let target: Option<Expr> = if input.peek(kw::target) {
+            input.parse::<kw::target>()?;
+            input.parse::<Token![:]>()?;
+            let t: Expr = input.parse()?;
+            input.parse::<Token![,]>()?;
+            Some(t)
+        } else {
+            None
+        };
+
+        // Check whether the next token is `format_string: &str` (which i
+        // always provided) or `level` (which is an optional expression).
+        // If `level` is provided, it comes before `format_string`.
+        let (level, format_string): (Option<Expr>, LitStr) = if input.peek(LitStr) {
+            // Only `format_string` is provided.
+            (None, input.parse()?)
+        } else {
+            // Both `level` and `format_string` are provided.
+            let level: Expr = input.parse()?;
+            input.parse::<Token![,]>()?;
+            let format_string: LitStr = input.parse()?;
+            (Some(level), format_string)
+        };
+
+        // Parse variadic arguments.
+        let formatting_args: Option<Punctuated<Expr, Token![,]>> = if input.is_empty() {
+            None
+        } else {
+            input.parse::<Token![,]>()?;
+            Some(Punctuated::parse_terminated(input)?)
+        };
+
+        Ok(Self {
+            ctx,
+            target,
+            level,
+            format_string,
+            formatting_args,
+        })
+    }
+}
+
+pub(crate) fn log(args: LogArgs, level: Option<TokenStream>) -> Result<TokenStream> {
+    let ctx = args.ctx;
+    let target = match args.target {
+        Some(t) => quote! { #t },
+        None => quote! { module_path!() },
+    };
+    let lvl: TokenStream = if let Some(l) = level {
+        l
+    } else if let Some(l) = args.level {
+        quote! { #l }
+    } else {
+        return Err(Error::new(
+            args.format_string.span(),
+            "missing `level` argument: try passing an `aya_log_ebpf::Level` value",
+        ));
+    };
+    let format_string = args.format_string;
+
+    let (num_args, write_args) = match args.formatting_args {
+        Some(formatting_args) => {
+            let formatting_exprs = formatting_args.iter();
+            let num_args = formatting_exprs.len();
+
+            let write_args = quote! {{
+                use ::aya_log_ebpf::WriteToBuf;
+                Ok::<_, ()>(record_len) #( .and_then(|record_len| {
+                    if record_len >= buf.buf.len() {
+                        return Err(());
+                    }
+                    { #formatting_exprs }.write(&mut buf.buf[record_len..]).map(|len| record_len + len)
+                }) )*
+            }};
+
+            (num_args, write_args)
+        }
+        None => (0, quote! {}),
+    };
+
+    // The way of writing to the perf buffer is different depending on whether
+    // we have variadic arguments or not.
+    let write_to_perf_buffer = if num_args > 0 {
+        // Writing with variadic arguments.
+        quote! {
+            if let Ok(record_len) = #write_args {
+                unsafe { ::aya_log_ebpf::AYA_LOGS.output(
+                    #ctx,
+                    &buf.buf[..record_len], 0
+                )}
+            }
+        }
+    } else {
+        // Writing with no variadic arguments.
+        quote! {
+            unsafe { ::aya_log_ebpf::AYA_LOGS.output(
+                #ctx,
+                &buf.buf[..record_len], 0
+            )}
+        }
+    };
+
+    Ok(quote! {
+        {
+            if let Some(buf_ptr) = unsafe { ::aya_log_ebpf::AYA_LOG_BUF.get_ptr_mut(0) } {
+                let buf = unsafe { &mut *buf_ptr };
+                if let Ok(header_len) = ::aya_log_ebpf::write_record_header(
+                    &mut buf.buf,
+                    #target,
+                    #lvl,
+                    module_path!(),
+                    file!(),
+                    line!(),
+                    #num_args,
+                ) {
+                    if let Ok(message_len) = ::aya_log_ebpf::write_record_message(
+                        &mut buf.buf[header_len..],
+                        #format_string,
+                    ) {
+                        let record_len = header_len + message_len;
+
+                        #write_to_perf_buffer
+                    }
+                }
+            }
+        }
+    })
+}
+
+pub(crate) fn error(args: LogArgs) -> Result<TokenStream> {
+    log(
+        args,
+        Some(quote! { ::aya_log_ebpf::macro_support::Level::Error }),
+    )
+}
+
+pub(crate) fn warn(args: LogArgs) -> Result<TokenStream> {
+    log(
+        args,
+        Some(quote! { ::aya_log_ebpf::macro_support::Level::Warn }),
+    )
+}
+
+pub(crate) fn info(args: LogArgs) -> Result<TokenStream> {
+    log(
+        args,
+        Some(quote! { ::aya_log_ebpf::macro_support::Level::Info }),
+    )
+}
+
+pub(crate) fn debug(args: LogArgs) -> Result<TokenStream> {
+    log(
+        args,
+        Some(quote! { ::aya_log_ebpf::macro_support::Level::Debug }),
+    )
+}
+
+pub(crate) fn trace(args: LogArgs) -> Result<TokenStream> {
+    log(
+        args,
+        Some(quote! { ::aya_log_ebpf::macro_support::Level::Trace }),
+    )
+}

aya-log-ebpf-macros/src/lib.rs

@@ -0,0 +1,52 @@
+use proc_macro::TokenStream;
+use syn::parse_macro_input;
+
+mod expand;
+
+#[proc_macro]
+pub fn log(args: TokenStream) -> TokenStream {
+    let args = parse_macro_input!(args as expand::LogArgs);
+    expand::log(args, None)
+        .unwrap_or_else(|err| err.to_compile_error())
+        .into()
+}
+
+#[proc_macro]
+pub fn error(args: TokenStream) -> TokenStream {
+    let args = parse_macro_input!(args as expand::LogArgs);
+    expand::error(args)
+        .unwrap_or_else(|err| err.to_compile_error())
+        .into()
+}
+
+#[proc_macro]
+pub fn warn(args: TokenStream) -> TokenStream {
+    let args = parse_macro_input!(args as expand::LogArgs);
+    expand::warn(args)
+        .unwrap_or_else(|err| err.to_compile_error())
+        .into()
+}
+
+#[proc_macro]
+pub fn info(args: TokenStream) -> TokenStream {
+    let args = parse_macro_input!(args as expand::LogArgs);
+    expand::info(args)
+        .unwrap_or_else(|err| err.to_compile_error())
+        .into()
+}
+
+#[proc_macro]
+pub fn debug(args: TokenStream) -> TokenStream {
+    let args = parse_macro_input!(args as expand::LogArgs);
+    expand::debug(args)
+        .unwrap_or_else(|err| err.to_compile_error())
+        .into()
+}
+
+#[proc_macro]
+pub fn trace(args: TokenStream) -> TokenStream {
+    let args = parse_macro_input!(args as expand::LogArgs);
+    expand::trace(args)
+        .unwrap_or_else(|err| err.to_compile_error())
+        .into()
+}

aya-log/Cargo.toml

@@ -0,0 +1,27 @@
+[package]
+name = "aya-log"
+version = "0.1.11-dev.0"
+description = "A logging library for eBPF programs."
+keywords = ["ebpf", "bpf", "log", "logging"]
+license = "MIT OR Apache-2.0"
+authors = ["The Aya Contributors"]
+repository = "https://github.com/aya-rs/aya-log"
+readme = "README.md"
+documentation = "https://docs.rs/aya-log"
+edition = "2018"
+
+[dependencies]
+aya = { path = "../aya", version = "0.11.0", features=["async_tokio"] }
+aya-log-common = { path = "../aya-log-common", version = "0.1.11-dev.0", features=["userspace"] }
+dyn-fmt = "0.3.0"
+thiserror = "1"
+log = "0.4"
+bytes = "1.1"
+tokio = { version = "1.2.0" }
+
+[dev-dependencies]
+simplelog = "0.12"
+testing_logger = "0.1.1"
+
+[lib]
+path = "src/lib.rs"

aya-log/README.md

@@ -0,0 +1,73 @@
+# aya-log - a logging library for eBPF programs
+
+## Overview
+
+`aya-log` is a logging library for eBPF programs written using [aya]. Think of
+it as the [log] crate for eBPF.
+
+## Installation
+
+### User space
+
+Add `aya-log` to `Cargo.toml`:
+
+```toml
+[dependencies]
+aya-log = { git = "https://github.com/aya-rs/aya-log", branch = "main" }
+```
+
+### eBPF side
+
+Add `aya-log-ebpf` to `Cargo.toml`:
+
+```toml
+[dependencies]
+aya-log-ebpf = { git = "https://github.com/aya-rs/aya-log", branch = "main" }
+```
+
+## Example
+
+Here's an example that uses `aya-log` in conjunction with the [simplelog] crate
+to log eBPF messages to the terminal.
+
+### User space code
+
+```rust
+use simplelog::{ColorChoice, ConfigBuilder, LevelFilter, TermLogger, TerminalMode};
+use aya_log::BpfLogger;
+
+TermLogger::init(
+    LevelFilter::Debug,
+    ConfigBuilder::new()
+        .set_target_level(LevelFilter::Error)
+        .set_location_level(LevelFilter::Error)
+        .build(),
+    TerminalMode::Mixed,
+    ColorChoice::Auto,
+)
+.unwrap();
+
+// Will log using the default logger, which is TermLogger in this case
+BpfLogger::init(&mut bpf).unwrap();
+```
+
+### eBPF code
+
+```rust
+use aya_log_ebpf::info;
+
+fn try_xdp_firewall(ctx: XdpContext) -> Result<u32, ()> {
+    if let Some(port) = tcp_dest_port(&ctx)? {
+        if block_port(port) {
+            info!(&ctx, "❌ blocked incoming connection on port: {}", port);
+            return Ok(XDP_DROP);
+        }
+    }
+
+    Ok(XDP_PASS)
+}
+```
+
+[aya]: https://github.com/aya-rs/aya
+[log]: https://docs.rs/log
+[simplelog]: https://docs.rs/simplelog

aya-log/release.toml

@@ -0,0 +1 @@
+shared-version = true

aya-log/src/lib.rs

@@ -0,0 +1,381 @@
+//! A logging framework for eBPF programs.
+//!
+//! This is the user space side of the [Aya] logging framework. For the eBPF
+//! side, see the `aya-log-ebpf` crate.
+//!
+//! `aya-log` provides the [BpfLogger] type, which reads log records created by
+//! `aya-log-ebpf` and logs them using the [log] crate. Any logger that
+//! implements the [Log] trait can be used with this crate.
+//!
+//! # Example:
+//!
+//! This example uses the [simplelog] crate to log messages to the terminal.
+//!
+//! ```no_run
+//! # let mut bpf = aya::Bpf::load(&[]).unwrap();
+//! use simplelog::{ColorChoice, ConfigBuilder, LevelFilter, TermLogger, TerminalMode};
+//! use aya_log::BpfLogger;
+//!
+//! // initialize simplelog::TermLogger as the default logger
+//! TermLogger::init(
+//!     LevelFilter::Debug,
+//!     ConfigBuilder::new()
+//!         .set_target_level(LevelFilter::Error)
+//!         .set_location_level(LevelFilter::Error)
+//!         .build(),
+//!     TerminalMode::Mixed,
+//!     ColorChoice::Auto,
+//! )
+//! .unwrap();
+//!
+//! // start reading aya-log records and log them using the default logger
+//! BpfLogger::init(&mut bpf).unwrap();
+//! ```
+//!
+//! With the following eBPF code:
+//!
+//! ```ignore
+//! # let ctx = ();
+//! use aya_log_ebpf::{debug, error, info, trace, warn};
+//!
+//! error!(&ctx, "this is an error message 🚨");
+//! warn!(&ctx, "this is a warning message ⚠️");
+//! info!(&ctx, "this is an info message ℹ️");
+//! debug!(&ctx, "this is a debug message ️🐝");
+//! trace!(&ctx, "this is a trace message 🔍");
+//! ```
+//! Outputs:
+//!
+//! ```text
+//! 21:58:55 [ERROR] xxx: [src/main.rs:35] this is an error message 🚨
+//! 21:58:55 [WARN] xxx: [src/main.rs:36] this is a warning message ⚠️
+//! 21:58:55 [INFO] xxx: [src/main.rs:37] this is an info message ℹ️
+//! 21:58:55 [DEBUG] (7) xxx: [src/main.rs:38] this is a debug message ️🐝
+//! 21:58:55 [TRACE] (7) xxx: [src/main.rs:39] this is a trace message 🔍
+//! ```
+//!
+//! [Aya]: https://docs.rs/aya
+//! [simplelog]: https://docs.rs/simplelog
+//! [Log]: https://docs.rs/log/0.4.14/log/trait.Log.html
+//! [log]: https://docs.rs/log
+//!
+use std::{convert::TryInto, io, mem, ptr, str, sync::Arc};
+
+use aya_log_common::{ArgType, RecordField, LOG_BUF_CAPACITY, LOG_FIELDS};
+use bytes::BytesMut;
+use dyn_fmt::AsStrFormatExt;
+use log::{error, Level, Log, Record};
+use thiserror::Error;
+
+use aya::{
+    maps::{
+        perf::{AsyncPerfEventArray, PerfBufferError},
+        MapError,
+    },
+    util::online_cpus,
+    Bpf, Pod,
+};
+
+/// Log messages generated by `aya_log_ebpf` using the [log] crate.
+///
+/// For more details see the [module level documentation](crate).
+pub struct BpfLogger;
+
+impl BpfLogger {
+    /// Starts reading log records created with `aya-log-ebpf` and logs them
+    /// with the default logger. See [log::logger].
+    pub fn init(bpf: &mut Bpf) -> Result<BpfLogger, Error> {
+        BpfLogger::init_with_logger(bpf, DefaultLogger {})
+    }
+
+    /// Starts reading log records created with `aya-log-ebpf` and logs them
+    /// with the given logger.
+    pub fn init_with_logger<T: Log + 'static>(
+        bpf: &mut Bpf,
+        logger: T,
+    ) -> Result<BpfLogger, Error> {
+        let logger = Arc::new(logger);
+        let mut logs: AsyncPerfEventArray<_> = bpf.map_mut("AYA_LOGS")?.try_into()?;
+
+        for cpu_id in online_cpus().map_err(Error::InvalidOnlineCpu)? {
+            let mut buf = logs.open(cpu_id, None)?;
+
+            let log = logger.clone();
+            tokio::spawn(async move {
+                let mut buffers = (0..10)
+                    .map(|_| BytesMut::with_capacity(LOG_BUF_CAPACITY))
+                    .collect::<Vec<_>>();
+
+                loop {
+                    let events = buf.read_events(&mut buffers).await.unwrap();
+
+                    #[allow(clippy::needless_range_loop)]
+                    for i in 0..events.read {
+                        let buf = &mut buffers[i];
+                        log_buf(buf, &*log).unwrap();
+                    }
+                }
+            });
+        }
+
+        Ok(BpfLogger {})
+    }
+}
+
+#[derive(Copy, Clone, Debug)]
+struct DefaultLogger;
+
+impl Log for DefaultLogger {
+    fn enabled(&self, metadata: &log::Metadata) -> bool {
+        log::logger().enabled(metadata)
+    }
+
+    fn log(&self, record: &Record) {
+        log::logger().log(record)
+    }
+
+    fn flush(&self) {
+        log::logger().flush()
+    }
+}
+
+#[derive(Error, Debug)]
+pub enum Error {
+    #[error("error opening log event array")]
+    MapError(#[from] MapError),
+
+    #[error("error opening log buffer")]
+    PerfBufferError(#[from] PerfBufferError),
+
+    #[error("invalid /sys/devices/system/cpu/online format")]
+    InvalidOnlineCpu(#[source] io::Error),
+}
+
+fn log_buf(mut buf: &[u8], logger: &dyn Log) -> Result<(), ()> {
+    let mut target = None;
+    let mut level = Level::Trace;
+    let mut module = None;
+    let mut file = None;
+    let mut line = None;
+    let mut log = None;
+    let mut num_args = None;
+
+    for _ in 0..LOG_FIELDS {
+        let (attr, rest) = unsafe { TagLenValue::<'_, RecordField>::try_read(buf)? };
+
+        match attr.tag {
+            RecordField::Target => {
+                target = Some(std::str::from_utf8(attr.value).map_err(|_| ())?);
+            }
+            RecordField::Level => {
+                level = unsafe { ptr::read_unaligned(attr.value.as_ptr() as *const _) }
+            }
+            RecordField::Module => {
+                module = Some(std::str::from_utf8(attr.value).map_err(|_| ())?);
+            }
+            RecordField::File => {
+                file = Some(std::str::from_utf8(attr.value).map_err(|_| ())?);
+            }
+            RecordField::Line => {
+                line = Some(u32::from_ne_bytes(attr.value.try_into().map_err(|_| ())?));
+            }
+            RecordField::NumArgs => {
+                num_args = Some(usize::from_ne_bytes(attr.value.try_into().map_err(|_| ())?));
+            }
+            RecordField::Log => {
+                log = Some(std::str::from_utf8(attr.value).map_err(|_| ())?);
+            }
+        }
+
+        buf = rest;
+    }
+
+    let log_msg = log.ok_or(())?;
+    let full_log_msg = match num_args {
+        Some(n) => {
+            let mut args: Vec<String> = Vec::new();
+            for _ in 0..n {
+                let (attr, rest) = unsafe { TagLenValue::<'_, ArgType>::try_read(buf)? };
+
+                match attr.tag {
+                    ArgType::I8 => {
+                        args.push(
+                            i8::from_ne_bytes(attr.value.try_into().map_err(|_| ())?).to_string(),
+                        );
+                    }
+                    ArgType::I16 => {
+                        args.push(
+                            i16::from_ne_bytes(attr.value.try_into().map_err(|_| ())?).to_string(),
+                        );
+                    }
+                    ArgType::I32 => {
+                        args.push(
+                            i32::from_ne_bytes(attr.value.try_into().map_err(|_| ())?).to_string(),
+                        );
+                    }
+                    ArgType::I64 => {
+                        args.push(
+                            i64::from_ne_bytes(attr.value.try_into().map_err(|_| ())?).to_string(),
+                        );
+                    }
+                    ArgType::I128 => {
+                        args.push(
+                            i128::from_ne_bytes(attr.value.try_into().map_err(|_| ())?).to_string(),
+                        );
+                    }
+                    ArgType::Isize => {
+                        args.push(
+                            isize::from_ne_bytes(attr.value.try_into().map_err(|_| ())?)
+                                .to_string(),
+                        );
+                    }
+                    ArgType::U8 => {
+                        args.push(
+                            u8::from_ne_bytes(attr.value.try_into().map_err(|_| ())?).to_string(),
+                        );
+                    }
+                    ArgType::U16 => {
+                        args.push(
+                            u16::from_ne_bytes(attr.value.try_into().map_err(|_| ())?).to_string(),
+                        );
+                    }
+                    ArgType::U32 => {
+                        args.push(
+                            u32::from_ne_bytes(attr.value.try_into().map_err(|_| ())?).to_string(),
+                        );
+                    }
+                    ArgType::U64 => {
+                        args.push(
+                            u64::from_ne_bytes(attr.value.try_into().map_err(|_| ())?).to_string(),
+                        );
+                    }
+                    ArgType::U128 => {
+                        args.push(
+                            u128::from_ne_bytes(attr.value.try_into().map_err(|_| ())?).to_string(),
+                        );
+                    }
+                    ArgType::Usize => {
+                        args.push(
+                            usize::from_ne_bytes(attr.value.try_into().map_err(|_| ())?)
+                                .to_string(),
+                        );
+                    }
+                    ArgType::F32 => {
+                        args.push(
+                            f32::from_ne_bytes(attr.value.try_into().map_err(|_| ())?).to_string(),
+                        );
+                    }
+                    ArgType::F64 => {
+                        args.push(
+                            f64::from_ne_bytes(attr.value.try_into().map_err(|_| ())?).to_string(),
+                        );
+                    }
+                    ArgType::Str => match str::from_utf8(attr.value) {
+                        Ok(v) => args.push(v.to_string()),
+                        Err(e) => error!("received invalid utf8 string: {}", e),
+                    },
+                }
+
+                buf = rest;
+            }
+
+            log_msg.format(&args)
+        }
+        None => log_msg.to_string(),
+    };
+
+    logger.log(
+        &Record::builder()
+            .args(format_args!("{}", full_log_msg))
+            .target(target.ok_or(())?)
+            .level(level)
+            .module_path(module)
+            .file(file)
+            .line(line)
+            .build(),
+    );
+    logger.flush();
+    Ok(())
+}
+
+struct TagLenValue<'a, T: Pod> {
+    tag: T,
+    value: &'a [u8],
+}
+
+impl<'a, T: Pod> TagLenValue<'a, T> {
+    unsafe fn try_read(mut buf: &'a [u8]) -> Result<(TagLenValue<'a, T>, &'a [u8]), ()> {
+        if buf.len() < mem::size_of::<T>() + mem::size_of::<usize>() {
+            return Err(());
+        }
+
+        let tag = ptr::read_unaligned(buf.as_ptr() as *const T);
+        buf = &buf[mem::size_of::<T>()..];
+
+        let len = usize::from_ne_bytes(buf[..mem::size_of::<usize>()].try_into().unwrap());
+        buf = &buf[mem::size_of::<usize>()..];
+
+        if buf.len() < len {
+            return Err(());
+        }
+
+        Ok((
+            TagLenValue {
+                tag,
+                value: &buf[..len],
+            },
+            &buf[len..],
+        ))
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use aya_log_common::{write_record_header, write_record_message, WriteToBuf};
+    use log::logger;
+    use testing_logger;
+
+    fn new_log(msg: &str, args: usize) -> Result<(usize, Vec<u8>), ()> {
+        let mut buf = vec![0; 8192];
+        let mut len = write_record_header(
+            &mut buf,
+            "test",
+            aya_log_common::Level::Info,
+            "test",
+            "test.rs",
+            123,
+            args,
+        )?;
+        len += write_record_message(&mut buf[len..], msg)?;
+        Ok((len, buf))
+    }
+
+    #[test]
+    fn test_str() {
+        testing_logger::setup();
+        let (_, input) = new_log("test", 0).unwrap();
+        let logger = logger();
+        let _ = log_buf(&input, logger);
+        testing_logger::validate(|captured_logs| {
+            assert_eq!(captured_logs.len(), 1);
+            assert_eq!(captured_logs[0].body, "test");
+            assert_eq!(captured_logs[0].level, Level::Info);
+        });
+    }
+
+    #[test]
+    fn test_str_with_args() {
+        testing_logger::setup();
+        let (len, mut input) = new_log("hello {}", 1).unwrap();
+        let name = "test";
+        (*name).write(&mut input[len..]).unwrap();
+        let logger = logger();
+        let _ = log_buf(&input, logger);
+        testing_logger::validate(|captured_logs| {
+            assert_eq!(captured_logs.len(), 1);
+            assert_eq!(captured_logs[0].body, "hello test");
+            assert_eq!(captured_logs[0].level, Level::Info);
+        });
+    }
+}

aya/src/maps/mod.rs

@@ -33,7 +33,7 @@
 //! versa. Because of that, all map values must be plain old data and therefore
 //! implement the [Pod] trait.
 use std::{
-    convert::TryFrom,
+    convert::{TryFrom, TryInto},
     ffi::CString,
     fmt, io,
     marker::PhantomData,
@@ -226,7 +226,7 @@ impl AsRawFd for MapFd {
 }
 
 #[derive(PartialEq, Eq, PartialOrd, Ord)]
-struct RlimitSize(u64);
+struct RlimitSize(usize);
 impl fmt::Display for RlimitSize {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         if self.0 < 1024 {
@@ -246,8 +246,9 @@ fn maybe_warn_rlimit() {
     let ret = unsafe { getrlimit(RLIMIT_MEMLOCK, limit.as_mut_ptr()) };
     if ret == 0 {
         let limit = unsafe { limit.assume_init() };
-        let limit: RlimitSize = RlimitSize(limit.rlim_cur);
+
-        if limit.0 == RLIM_INFINITY {
+        let limit: RlimitSize = RlimitSize(limit.rlim_cur.try_into().unwrap());
+        if limit.0 == RLIM_INFINITY.try_into().unwrap() {
             return;
         }
         warn!(

bpf/.cargo/config.toml

@@ -0,0 +1,6 @@
+[build]
+target-dir = "../target"
+target = "bpfel-unknown-none"
+
+[unstable]
+build-std = ["core"]

bpf/Cargo.toml

@@ -1,2 +0,0 @@
-[workspace]
-members = ["aya-bpf", "aya-bpf-macros", "aya-bpf-bindings"]

bpf/aya-bpf/Cargo.toml

@@ -6,5 +6,8 @@ edition = "2018"
 
 [dependencies]
 aya-bpf-cty = { path = "../aya-bpf-cty" }
-aya-bpf-macros = { path = "../aya-bpf-macros" }
+aya-bpf-macros = { path = "../../aya-bpf-macros" }
 aya-bpf-bindings = { path = "../aya-bpf-bindings" }
+
+[build-dependencies]
+rustversion = "1.0"

bpf/aya-bpf/build.rs

@@ -1,6 +1,7 @@
 use std::env;
 
 fn main() {
+    check_rust_version();
     println!("cargo:rerun-if-env-changed=CARGO_CFG_BPF_TARGET_ARCH");
     if let Ok(arch) = env::var("CARGO_CFG_BPF_TARGET_ARCH") {
         println!("cargo:rustc-cfg=bpf_target_arch=\"{}\"", arch);
@@ -10,3 +11,11 @@ fn main() {
         println!("cargo:rustc-cfg=bpf_target_arch=\"{}\"", arch);
     }
 }
+
+#[rustversion::nightly]
+fn check_rust_version() {
+    println!("cargo:rustc-cfg=unstable");
+}
+
+#[rustversion::not(nightly)]
+fn check_rust_version() {}

bpf/aya-bpf/src/lib.rs

@@ -9,7 +9,7 @@
     html_logo_url = "https://aya-rs.dev/assets/images/crabby.svg",
     html_favicon_url = "https://aya-rs.dev/assets/images/crabby.svg"
 )]
-#![feature(never_type)]
+#![cfg_attr(unstable, feature(never_type))]
 #![allow(clippy::missing_safety_doc)]
 #![no_std]
 

bpf/aya-bpf/src/maps/program_array.rs

@@ -80,6 +80,30 @@ impl ProgramArray {
     ///
     /// On success, this function **does not return** into the original program.
     /// On failure, a negative error is returned, wrapped in `Err()`.
+    #[cfg(not(unstable))]
+    pub unsafe fn tail_call<C: BpfContext>(&self, ctx: &C, index: u32) -> Result<(), c_long> {
+        let res = bpf_tail_call(ctx.as_ptr(), self.def.get() as *mut _, index);
+        if res != 0 {
+            Err(res)
+        } else {
+            unreachable_unchecked()
+        }
+    }
+
+    /// Perform a tail call into a program indexed by this map.
+    ///
+    /// # Safety
+    ///
+    /// This function is inherently unsafe, since it causes control flow to jump into
+    /// another eBPF program. This can have side effects, such as drop methods not being
+    /// called. Note that tail calling into an eBPF program is not the same thing as
+    /// a function call -- control flow never returns to the caller.
+    ///
+    /// # Return Value
+    ///
+    /// On success, this function **does not return** into the original program.
+    /// On failure, a negative error is returned, wrapped in `Err()`.
+    #[cfg(unstable)]
     pub unsafe fn tail_call<C: BpfContext>(&self, ctx: &C, index: u32) -> Result<!, c_long> {
         let res = bpf_tail_call(ctx.as_ptr(), self.def.get() as *mut _, index);
         if res != 0 {

bpf/aya-log-ebpf/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "aya-log-ebpf"
+version = "0.1.0"
+edition = "2018"
+
+[dependencies]
+aya-bpf = { path = "../aya-bpf" }
+aya-log-common = { path = "../../aya-log-common" }
+aya-log-ebpf-macros = { path = "../../aya-log-ebpf-macros" }
+
+[lib]
+path = "src/lib.rs"

bpf/aya-log-ebpf/src/lib.rs

@@ -0,0 +1,29 @@
+#![no_std]
+use aya_bpf::{
+    macros::map,
+    maps::{PerCpuArray, PerfEventByteArray},
+};
+pub use aya_log_common::{
+    write_record_header, write_record_message, Level, WriteToBuf, LOG_BUF_CAPACITY,
+};
+pub use aya_log_ebpf_macros::{debug, error, info, log, trace, warn};
+
+#[doc(hidden)]
+#[repr(C)]
+pub struct LogBuf {
+    pub buf: [u8; LOG_BUF_CAPACITY],
+}
+
+#[doc(hidden)]
+#[map]
+pub static mut AYA_LOG_BUF: PerCpuArray<LogBuf> = PerCpuArray::with_max_entries(1, 0);
+
+#[doc(hidden)]
+#[map]
+pub static mut AYA_LOGS: PerfEventByteArray = PerfEventByteArray::new(0);
+
+#[doc(hidden)]
+pub mod macro_support {
+    pub use aya_log_common::{Level, LOG_BUF_CAPACITY};
+    pub use aya_log_ebpf_macros::log;
+}

bpf/rust-toolchain.toml

@@ -0,0 +1,2 @@
+[toolchain]
+channel = "nightly"

bpf/rustfmt.toml

@@ -1 +0,0 @@
-../rustfmt.toml

netlify.toml

@@ -1,3 +1,3 @@
 [build]
   publish = "site"
-  command = "rustup toolchain install nightly && cargo xtask docs"
+  command = "rustup toolchain install nightly -c rust-src && cargo xtask docs"

release.toml

@@ -0,0 +1,6 @@
+pre-release-commit-message = "{crate_name}: release version {{version}}"
+post-release-commit-message = "{crate_name}: start next development iteration {{next_version}}"
+consolidate-pushes = true
+consolidate-commits = true
+dev-version = true
+dev-version-ext = "dev.0"

test/integration-ebpf/Cargo.toml

@@ -22,15 +22,3 @@ path = "src/pass.rs"
 [[bin]]
 name = "test"
 path = "src/test.rs"
-
-[profile.dev]
-panic = "abort"
-opt-level = 2
-overflow-checks = false
-
-[profile.release]
-panic = "abort"
-debug = 2
-
-[workspace]
-members = []

xtask/src/docs/mod.rs

@@ -8,67 +8,19 @@ use std::{fs, io, io::Write};
 use indoc::indoc;
 
 pub fn docs() -> Result<(), anyhow::Error> {
-    let mut working_dir = PathBuf::from(".");
+    let current_dir = PathBuf::from(".");
-
+    let header_path = current_dir.join("header.html");
-    let replace = Command::new("sed")
-        .current_dir(&working_dir)
-        .args(vec![
-            "-i.bak",
-            "s/crabby.svg/crabby_dev.svg/",
-            "aya/src/lib.rs",
-        ])
-        .status()
-        .expect("failed to replace logo");
-    assert!(replace.success());
-
-    let mut header_path = PathBuf::from(".");
-    header_path.push("header.html");
     let mut header = fs::File::create(&header_path).expect("can't create header.html");
     header
         .write_all(r#"<meta name="robots" content="noindex">"#.as_bytes())
         .expect("can't write header.html contents");
     header.flush().expect("couldn't flush contents");
-
     let abs_header_path = fs::canonicalize(&header_path).unwrap();
-    let args = vec!["+nightly", "doc", "--no-deps", "--all-features"];
 
-    let status = Command::new("cargo")
+    build_docs(&current_dir.join("aya"), &abs_header_path)?;
-        .current_dir(&working_dir)
+    build_docs(&current_dir.join("bpf/aya-bpf"), &abs_header_path)?;
-        .env(
+    copy_dir_all("./target/doc", "./site/user")?;
-            "RUSTDOCFLAGS",
+    copy_dir_all("./target/bpfel-unknown-none/doc", "./site/bpf")?;
-            format!("--html-in-header {}", abs_header_path.to_str().unwrap()),
-        )
-        .args(&args)
-        .status()
-        .expect("failed to build aya docs");
-    assert!(status.success());
-
-    working_dir.push("bpf");
-
-    let replace = Command::new("sed")
-        .current_dir(&working_dir)
-        .args(vec![
-            "-i.bak",
-            "s/crabby.svg/crabby_dev.svg/",
-            "aya-bpf/src/lib.rs",
-        ])
-        .status()
-        .expect("failed to replace logo");
-    assert!(replace.success());
-
-    let status = Command::new("cargo")
-        .current_dir(&working_dir)
-        .env(
-            "RUSTDOCFLAGS",
-            format!("--html-in-header {}", abs_header_path.to_str().unwrap()),
-        )
-        .args(&args)
-        .status()
-        .expect("failed to build aya-bpf docs");
-    assert!(status.success());
-
-    copy_dir_all("./target/doc", "site/user")?;
-    copy_dir_all("./bpf/target/doc", "site/bpf")?;
 
     let mut robots = fs::File::create("site/robots.txt").expect("can't create robots.txt");
     robots
@@ -98,14 +50,38 @@ pub fn docs() -> Result<(), anyhow::Error> {
             .as_bytes(),
         )
         .expect("can't write index.html");
+    Ok(())
+}
+
+fn build_docs(working_dir: &PathBuf, abs_header_path: &Path) -> Result<(), anyhow::Error> {
+    let replace = Command::new("sed")
+        .current_dir(&working_dir)
+        .args(vec!["-i.bak", "s/crabby.svg/crabby_dev.svg/", "src/lib.rs"])
+        .status()
+        .expect("failed to replace logo");
+    assert!(replace.success());
 
-    fs::rename("aya/src/lib.rs.bak", "aya/src/lib.rs").unwrap();
+    let args = vec!["+nightly", "doc", "--no-deps", "--all-features"];
-    fs::rename("bpf/aya-bpf/src/lib.rs.bak", "bpf/aya-bpf/src/lib.rs").unwrap();
 
+    let status = Command::new("cargo")
+        .current_dir(&working_dir)
+        .env(
+            "RUSTDOCFLAGS",
+            format!("--html-in-header {}", abs_header_path.to_str().unwrap()),
+        )
+        .args(&args)
+        .status()
+        .expect("failed to build aya docs");
+    assert!(status.success());
+    fs::rename(
+        working_dir.join("src/lib.rs.bak"),
+        working_dir.join("src/lib.rs"),
+    )
+    .unwrap();
     Ok(())
 }
 
-fn copy_dir_all<P: AsRef<Path>>(src: P, dst: P) -> io::Result<()> {
+fn copy_dir_all<P1: AsRef<Path>, P2: AsRef<Path>>(src: P1, dst: P2) -> io::Result<()> {
     fs::create_dir_all(&dst)?;
     for entry in fs::read_dir(src)? {
         let entry = entry?;