Add names to memfds

I was confused while debugging what role was pertaining to what fd

Signed-off-by: Bob Weinand <[email protected]>

ipc/src/platform/unix/mem_handle.rs

@@ -44,17 +44,17 @@ static ANON_SHM_ID: AtomicI32 = AtomicI32::new(0);
 
 impl ShmHandle {
     #[cfg(target_os = "linux")]
-    fn open_anon_shm() -> anyhow::Result<OwnedFd> {
-        if let Ok(memfd) = memfd::MemfdOptions::default().create("anon-shm-handle") {
+    fn open_anon_shm(name: &str) -> anyhow::Result<OwnedFd> {
+        if let Ok(memfd) = memfd::MemfdOptions::default().create(name) {
             Ok(memfd.into_file().into())
         } else {
-            Self::open_anon_shm_generic()
+            Self::open_anon_shm_generic(name)
         }
     }
 
-    fn open_anon_shm_generic() -> anyhow::Result<OwnedFd> {
+    fn open_anon_shm_generic(name: &str) -> anyhow::Result<OwnedFd> {
         let path = format!(
-            "/libdatadog-shm-anon-{}-{}",
+            "/libdatadog-shm-{name}-{}-{}",
             unsafe { libc::getpid() },
             ANON_SHM_ID.fetch_add(1, Ordering::SeqCst)
         );
@@ -68,12 +68,16 @@ impl ShmHandle {
     }
 
     #[cfg(not(target_os = "linux"))]
-    fn open_anon_shm() -> anyhow::Result<OwnedFd> {
-        Self::open_anon_shm_generic()
+    fn open_anon_shm(name: &str) -> anyhow::Result<OwnedFd> {
+        Self::open_anon_shm_generic(name)
     }
 
     pub fn new(size: usize) -> anyhow::Result<ShmHandle> {
-        let fd = Self::open_anon_shm()?;
+        Self::new_named(size, "anon-handle")
+    }
+
+    pub fn new_named(size: usize, name: &str) -> anyhow::Result<ShmHandle> {
+        let fd = Self::open_anon_shm(name)?;
         let handle: PlatformHandle<OwnedFd> = fd.into();
         ftruncate(handle.as_owned_fd()?, size as off_t)?;
         Ok(ShmHandle { handle, size })

ipc/src/platform/unix/mem_handle_macos.rs

@@ -69,7 +69,7 @@ static ANON_SHM_ID: AtomicI32 = AtomicI32::new(0);
 impl ShmHandle {
     pub fn new(size: usize) -> anyhow::Result<ShmHandle> {
         let path = format!(
-            "dd-shm-anon-{}-{}",
+            "ddshm-anon-{}-{}",
             unsafe { libc::getpid() },
             ANON_SHM_ID.fetch_add(1, Ordering::SeqCst)
         );
@@ -85,6 +85,10 @@ impl ShmHandle {
             size: size | NOT_COMMITTED,
         })
     }
+
+    pub fn new_named(size: usize, _name: &str) -> anyhow::Result<ShmHandle> {
+        Self::new(size)
+    }
 }
 fn path_slice(path: &CStr) -> &[u8] {
     assert_eq!(path.to_bytes()[0], b'/');

ipc/src/platform/windows/mem_handle.rs

@@ -91,12 +91,16 @@ static ANON_HANDLE_COUNTER: AtomicU32 = AtomicU32::new(0);
 
 impl ShmHandle {
     pub fn new(size: usize) -> anyhow::Result<ShmHandle> {
+        Self::new_named(size, "shm-handle")
+    }
+
+    pub fn new_named(size: usize, name: &str) -> anyhow::Result<ShmHandle> {
         // If one uses null_mut() for the name, DuplicateHandle will emit a very
         // confusing "The system cannot find the file specified. (os error 2)".
         // It seems like DuplicateHandle requires a name to re-open the FileMapping
         // within another process. Oh well. Let's generate an unique one.
         let name = CString::new(format!(
-            "libdatadog-anon-{}-{}",
+            "libdatadog-anon-{name}-{}-{}",
             unsafe { libc::getpid() },
             ANON_HANDLE_COUNTER.fetch_add(1, Ordering::SeqCst)
         ))

sidecar-ffi/src/lib.rs

@@ -23,7 +23,7 @@ use datadog_sidecar::shm_remote_config::{path_for_remote_config, RemoteConfigRea
 use ddcommon::tag::Tag;
 use ddcommon::Endpoint;
 use ddcommon_ffi as ffi;
-use ddcommon_ffi::MaybeError;
+use ddcommon_ffi::{CharSlice, MaybeError};
 use ddtelemetry::{
     data::{self, Dependency, Integration},
     worker::{LifecycleAction, TelemetryActions},
@@ -94,6 +94,18 @@ pub extern "C" fn ddog_alloc_anon_shm_handle(
     MaybeError::None
 }
 
+#[no_mangle]
+pub extern "C" fn ddog_alloc_anon_shm_handle_named(
+    size: usize,
+    handle: &mut *mut ShmHandle,
+    name: CharSlice,
+) -> MaybeError {
+    let name = name.to_utf8_lossy();
+    *handle = Box::into_raw(Box::new(try_c!(ShmHandle::new_named(size, name.as_ref()))));
+
+    MaybeError::None
+}
+
 #[no_mangle]
 pub extern "C" fn ddog_map_shm(
     handle: Box<ShmHandle>,