aya-log: Move the `Pod` implementations from aya-log-common to aya-log

Keeping the `Pod` implementations and optional dependency on aya in
aya-log-common breaks the clippy checks (which are made on the entire
workspace).

The reason is that when different crates inside the workspace have the
same dependency with different features, that dependency is built only
once with the sum of features needed by all crates. It's **not** being
built separately with different feature sets.

That's why, before this change, aya-log-common was built once for the
entire workspace with `userspace` feature enabled. That made importing
aya-log-ebpf inside integration-ebpf impossible. The aya-log-common
build, with `userspace` feature enabled, was pulling std as a
dependency. Therefore, importing aya-log-ebpf inside integration-ebpf
resulted in including std and errors like:

```
error[E0152]: found duplicate lang item `panic_impl`
  --> test/integration-ebpf/src/log.rs:23:1
   |
23 | fn panic(_info: &core::panic::PanicInfo) -> ! {
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: the lang item is first defined in crate `std` (which `aya` depends on)
```

This change fixes the problem by removing the `userspace` feature from
aya-log-common and moving the `Pod` implementations to aya-log.

aya-log-common/Cargo.toml

@@ -9,12 +9,7 @@ repository = "https://github.com/aya-rs/aya-log"
 documentation = "https://docs.rs/aya-log"
 edition = "2021"
 
-[features]
-default = []
-userspace = [ "aya" ]
-
 [dependencies]
-aya = { path = "../aya", version = "0.11.0", optional=true }
 num_enum = { version = "0.6", default-features = false }
 
 [lib]

aya-log-common/src/lib.rs

@@ -96,15 +96,6 @@ pub enum DisplayHint {
     UpperMac,
 }
 
-#[cfg(feature = "userspace")]
-mod userspace {
-    use super::*;
-
-    unsafe impl aya::Pod for RecordField {}
-    unsafe impl aya::Pod for Argument {}
-    unsafe impl aya::Pod for DisplayHint {}
-}
-
 struct TagLenValue<'a, T> {
     tag: T,
     value: &'a [u8],

aya-log/Cargo.toml

@@ -12,7 +12,7 @@ edition = "2021"
 
 [dependencies]
 aya = { path = "../aya", version = "0.11.0", features=["async_tokio"] }
-aya-log-common = { path = "../aya-log-common", version = "0.1.13", features=["userspace"] }
+aya-log-common = { path = "../aya-log-common", version = "0.1.13" }
 thiserror = "1"
 log = "0.4"
 bytes = "1.1"

aya-log/src/lib.rs

@@ -73,6 +73,20 @@ use aya::{
     Bpf, Pod,
 };
 
+#[derive(Copy, Clone)]
+#[repr(transparent)]
+struct RecordFieldWrapper(RecordField);
+#[derive(Copy, Clone)]
+#[repr(transparent)]
+struct ArgumentWrapper(Argument);
+#[derive(Copy, Clone)]
+#[repr(transparent)]
+struct DisplayHintWrapper(DisplayHint);
+
+unsafe impl aya::Pod for RecordFieldWrapper {}
+unsafe impl aya::Pod for ArgumentWrapper {}
+unsafe impl aya::Pod for DisplayHintWrapper {}
+
 /// Log messages generated by `aya_log_ebpf` using the [log] crate.
 ///
 /// For more details see the [module level documentation](crate).
@@ -197,12 +211,12 @@ impl Formatter<[u8; 6]> for UpperMacFormatter {
 }
 
 trait Format {
-    fn format(&self, last_hint: Option<DisplayHint>) -> Result<String, ()>;
+    fn format(&self, last_hint: Option<DisplayHintWrapper>) -> Result<String, ()>;
 }
 
 impl Format for u32 {
-    fn format(&self, last_hint: Option<DisplayHint>) -> Result<String, ()> {
-        match last_hint {
+    fn format(&self, last_hint: Option<DisplayHintWrapper>) -> Result<String, ()> {
+        match last_hint.map(|h| h.0) {
             Some(DisplayHint::Default) => Ok(DefaultFormatter::format(self)),
             Some(DisplayHint::LowerHex) => Ok(LowerHexFormatter::format(self)),
             Some(DisplayHint::UpperHex) => Ok(UpperHexFormatter::format(self)),
@@ -216,8 +230,8 @@ impl Format for u32 {
 }
 
 impl Format for [u8; 6] {
-    fn format(&self, last_hint: Option<DisplayHint>) -> Result<String, ()> {
-        match last_hint {
+    fn format(&self, last_hint: Option<DisplayHintWrapper>) -> Result<String, ()> {
+        match last_hint.map(|h| h.0) {
             Some(DisplayHint::Default) => Err(()),
             Some(DisplayHint::LowerHex) => Err(()),
             Some(DisplayHint::UpperHex) => Err(()),
@@ -231,8 +245,8 @@ impl Format for [u8; 6] {
 }
 
 impl Format for [u8; 16] {
-    fn format(&self, last_hint: Option<DisplayHint>) -> Result<String, ()> {
-        match last_hint {
+    fn format(&self, last_hint: Option<DisplayHintWrapper>) -> Result<String, ()> {
+        match last_hint.map(|h| h.0) {
             Some(DisplayHint::Default) => Err(()),
             Some(DisplayHint::LowerHex) => Err(()),
             Some(DisplayHint::UpperHex) => Err(()),
@@ -246,8 +260,8 @@ impl Format for [u8; 16] {
 }
 
 impl Format for [u16; 8] {
-    fn format(&self, last_hint: Option<DisplayHint>) -> Result<String, ()> {
-        match last_hint {
+    fn format(&self, last_hint: Option<DisplayHintWrapper>) -> Result<String, ()> {
+        match last_hint.map(|h| h.0) {
             Some(DisplayHint::Default) => Err(()),
             Some(DisplayHint::LowerHex) => Err(()),
             Some(DisplayHint::UpperHex) => Err(()),
@@ -263,8 +277,8 @@ impl Format for [u16; 8] {
 macro_rules! impl_format {
     ($type:ident) => {
         impl Format for $type {
-            fn format(&self, last_hint: Option<DisplayHint>) -> Result<String, ()> {
-                match last_hint {
+            fn format(&self, last_hint: Option<DisplayHintWrapper>) -> Result<String, ()> {
+                match last_hint.map(|h| h.0) {
                     Some(DisplayHint::Default) => Ok(DefaultFormatter::format(self)),
                     Some(DisplayHint::LowerHex) => Ok(LowerHexFormatter::format(self)),
                     Some(DisplayHint::UpperHex) => Ok(UpperHexFormatter::format(self)),
@@ -293,8 +307,8 @@ impl_format!(usize);
 macro_rules! impl_format_float {
     ($type:ident) => {
         impl Format for $type {
-            fn format(&self, last_hint: Option<DisplayHint>) -> Result<String, ()> {
-                match last_hint {
+            fn format(&self, last_hint: Option<DisplayHintWrapper>) -> Result<String, ()> {
+                match last_hint.map(|h| h.0) {
                     Some(DisplayHint::Default) => Ok(DefaultFormatter::format(self)),
                     Some(DisplayHint::LowerHex) => Err(()),
                     Some(DisplayHint::UpperHex) => Err(()),
@@ -353,9 +367,9 @@ fn log_buf(mut buf: &[u8], logger: &dyn Log) -> Result<(), ()> {
     let mut num_args = None;
 
     for _ in 0..LOG_FIELDS {
-        let (attr, rest) = unsafe { TagLenValue::<'_, RecordField>::try_read(buf)? };
+        let (attr, rest) = unsafe { TagLenValue::<'_, RecordFieldWrapper>::try_read(buf)? };
 
-        match attr.tag {
+        match attr.tag.0 {
             RecordField::Target => {
                 target = Some(std::str::from_utf8(attr.value).map_err(|_| ())?);
             }
@@ -380,11 +394,11 @@ fn log_buf(mut buf: &[u8], logger: &dyn Log) -> Result<(), ()> {
     }
 
     let mut full_log_msg = String::new();
-    let mut last_hint: Option<DisplayHint> = None;
+    let mut last_hint: Option<DisplayHintWrapper> = None;
     for _ in 0..num_args.ok_or(())? {
-        let (attr, rest) = unsafe { TagLenValue::<'_, Argument>::try_read(buf)? };
+        let (attr, rest) = unsafe { TagLenValue::<'_, ArgumentWrapper>::try_read(buf)? };
 
-        match attr.tag {
+        match attr.tag.0 {
             Argument::DisplayHint => {
                 last_hint = Some(unsafe { ptr::read_unaligned(attr.value.as_ptr() as *const _) });
             }