Map shared memory region as read-only in receiver

apis/rust/node/Cargo.toml

@@ -24,7 +24,7 @@ flume = "0.10.14"
 uuid = { version = "1.1.2", features = ["v4"] }
 capnp = "0.14.11"
 bincode = "1.3.3"
-shared_memory = "0.12.0"
+shared_memory_extended = "0.13.0"
 dora-tracing = { workspace = true, optional = true }
 arrow = "35.0.0"
 

apis/rust/node/src/event_stream/event.rs

@@ -5,7 +5,7 @@ use dora_core::{
     message::Metadata,
 };
 use eyre::Context;
-use shared_memory::{Shmem, ShmemConf};
+use shared_memory_extended::{Shmem, ShmemConf};
 
 #[derive(Debug)]
 #[non_exhaustive]
@@ -78,6 +78,7 @@ impl MappedInputData {
         let memory = Box::new(
             ShmemConf::new()
                 .os_id(shared_memory_id)
+                .writable(false)
                 .open()
                 .wrap_err("failed to map shared memory input")?,
         );

apis/rust/node/src/node/mod.rs

@@ -8,7 +8,7 @@ use dora_core::{
     message::{uhlc, Metadata, MetadataParameters},
 };
 use eyre::{bail, WrapErr};
-use shared_memory::{Shmem, ShmemConf};
+use shared_memory_extended::{Shmem, ShmemConf};
 use std::{
     collections::{HashMap, VecDeque},
     ops::{Deref, DerefMut},
@@ -219,6 +219,7 @@ impl DoraNode {
             None => ShmemHandle(Box::new(
                 ShmemConf::new()
                     .size(data_len)
+                    .writable(true)
                     .create()
                     .wrap_err("failed to allocate shared memory")?,
             )),

examples/python-operator-dataflow/plot.py

@@ -58,6 +58,7 @@ def on_input(
                 dora_input["value"]
                 .to_numpy()
                 .reshape((CAMERA_HEIGHT, CAMERA_WIDTH, 3))
+                .copy() # copy the image because we want to modify it below
             )
             self.image = frame
 

libraries/shared-memory-server/Cargo.toml

@@ -11,7 +11,7 @@ license.workspace = true
 [dependencies]
 eyre = "0.6.8"
 serde = { version = "1.0.152", features = ["derive"] }
-shared_memory = "0.12.0"
+shared_memory_extended = "0.13.0"
 # TODO use upstream release once https://github.com/elast0ny/raw_sync-rs/pull/29 is merged
 # Current fix, use personally pushed `raw_sync_2` version.
 raw_sync_2 = "0.1.5"

libraries/shared-memory-server/src/channel.rs

@@ -1,7 +1,7 @@
 use eyre::{eyre, Context};
 use raw_sync_2::events::{Event, EventImpl, EventInit, EventState};
 use serde::{Deserialize, Serialize};
-use shared_memory::Shmem;
+use shared_memory_extended::Shmem;
 use std::{
     mem, slice,
     sync::atomic::{AtomicBool, AtomicU64},

libraries/shared-memory-server/src/lib.rs

@@ -1,7 +1,7 @@
 use self::channel::ShmemChannel;
 use eyre::{eyre, Context};
 use serde::{Deserialize, Serialize};
-pub use shared_memory::{Shmem, ShmemConf};
+pub use shared_memory_extended::{Shmem, ShmemConf};
 use std::marker::PhantomData;
 use std::time::Duration;
 
@@ -14,7 +14,7 @@
 }
 
 impl<T, U> ShmemServer<T, U> {
     pub unsafe fn new(memory: Shmem) -> eyre::Result<Self> {
         Ok(Self {
             channel: ShmemChannel::new_server(memory)?,
             reply_expected: false,
@@ -53,7 +53,7 @@
 }
 
 impl<T, U> ShmemClient<T, U> {
     pub unsafe fn new(memory: Shmem, timeout: Option<Duration>) -> eyre::Result<Self> {
         Ok(Self {
             channel: ShmemChannel::new_client(memory)?,
             timeout,