Take dependency on zerocopy for safe transmutation

Author: daniel-levin

perf-event-open-sys/Cargo.toml

@@ -25,3 +25,4 @@ name = "perf_event_open_sys"
 [dependencies]
 libc = "0.2"
 memoffset = "0.9.1"
+zerocopy = { version = "0.8.26", features = ["derive"] }

perf-event-open-sys/src/bindings_aarch64.rs

@@ -2578,7 +2578,7 @@ impl ::std::fmt::Debug for perf_event_mmap_page {
     }
 }
 #[repr(C)]
-#[derive(Debug, Default, Copy, Clone)]
+#[derive(Debug, Default, Copy, Clone, zerocopy::FromBytes)]
 pub struct perf_event_header {
     pub type_: __u32,
     pub misc: __u16,

perf-event-open-sys/src/bindings_riscv64gc.rs

@@ -2578,7 +2578,7 @@ impl ::std::fmt::Debug for perf_event_mmap_page {
     }
 }
 #[repr(C)]
-#[derive(Debug, Default, Copy, Clone)]
+#[derive(Debug, Default, Copy, Clone, zerocopy::FromBytes)]
 pub struct perf_event_header {
     pub type_: __u32,
     pub misc: __u16,

perf-event-open-sys/src/bindings_x86_64.rs

@@ -2622,7 +2622,7 @@ impl ::std::fmt::Debug for perf_event_mmap_page {
     }
 }
 #[repr(C)]
-#[derive(Debug, Default, Copy, Clone)]
+#[derive(Debug, Default, Copy, Clone, zerocopy::FromBytes)]
 pub struct perf_event_header {
     pub type_: __u32,
     pub misc: __u16,

perf-event/Cargo.toml

@@ -29,6 +29,7 @@ libc = "0.2"
 memmap2 = "0.9"
 perf-event-data = "0.1.8"
 perf-event-open-sys2 = "5.0.4"
+zerocopy = "0.8.26"
 
 [dev-dependencies]
 ctrlc = "3.4.5"

perf-event/src/sampler.rs

@@ -671,9 +671,7 @@ impl<'a> ByteBuffer<'a> {
     fn parse_header(&mut self) -> perf_event_header {
         let mut bytes = [0; std::mem::size_of::<perf_event_header>()];
         self.copy_to_slice(&mut bytes);
-        // SAFETY: perf_event_header is a packed C struct so it is valid to
-        //         copy arbitrary initialized memory into it.
-        unsafe { std::mem::transmute(bytes) }
+        zerocopy::transmute!(bytes)
     }
 
     fn len(&self) -> usize {