From 1d7280bc3ceaa7496300f718e0327568192c26e9 Mon Sep 17 00:00:00 2001
From: yellowhatter <bannov.dy@gmail.com>
Date: Tue, 12 Nov 2024 23:44:06 +0300
Subject: [PATCH 1/8] Proper SHM subsystem support

---
 rmw_zenoh_cpp/CMakeLists.txt                  |  9 ++
 .../DEFAULT_RMW_ZENOH_ROUTER_CONFIG.json5     |  4 +-
 .../DEFAULT_RMW_ZENOH_SESSION_CONFIG.json5    |  4 +-
 .../src/detail/rmw_context_impl_s.cpp         | 88 +++++++++--------
 .../src/detail/rmw_context_impl_s.hpp         | 21 +++--
 .../src/detail/rmw_publisher_data.cpp         | 50 +++++++---
 .../src/detail/rmw_publisher_data.hpp         | 15 ++-
 .../src/detail/rmw_subscription_data.hpp      |  8 +-
 rmw_zenoh_cpp/src/detail/shm_context.cpp      | 26 +++++
 rmw_zenoh_cpp/src/detail/shm_context.hpp      | 33 +++++++
 rmw_zenoh_cpp/src/detail/zenoh_config.cpp     | 94 +++++++++++++++++++
 rmw_zenoh_cpp/src/detail/zenoh_config.hpp     | 30 ++++++
 rmw_zenoh_cpp/src/rmw_zenoh.cpp               | 14 ++-
 zenoh_c_vendor/CMakeLists.txt                 |  5 +-
 14 files changed, 327 insertions(+), 74 deletions(-)
 create mode 100644 rmw_zenoh_cpp/src/detail/shm_context.cpp
 create mode 100644 rmw_zenoh_cpp/src/detail/shm_context.hpp

diff --git a/rmw_zenoh_cpp/CMakeLists.txt b/rmw_zenoh_cpp/CMakeLists.txt
index 69939fd9..23b1115d 100644
--- a/rmw_zenoh_cpp/CMakeLists.txt
+++ b/rmw_zenoh_cpp/CMakeLists.txt
@@ -11,6 +11,8 @@ if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
   add_compile_options(-Wall -Wextra -Wpedantic)
 endif()
 
+set(RMW_ZENOH_BUILD_WITH_SHARED_MEMORY OFF CACHE BOOL "Compile Zenoh RMW with Shared Memory support")
+
 # find dependencies
 find_package(ament_cmake REQUIRED)
 
@@ -80,6 +82,13 @@ target_compile_definitions(rmw_zenoh_cpp
     RMW_VERSION_PATCH=${rmw_VERSION_PATCH}
 )
 
+if(${RMW_ZENOH_BUILD_WITH_SHARED_MEMORY})
+  target_compile_definitions(rmw_zenoh_cpp
+    PRIVATE
+      RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+  )
+endif()
+
 ament_export_targets(export_rmw_zenoh_cpp)
 
 register_rmw_implementation(
diff --git a/rmw_zenoh_cpp/config/DEFAULT_RMW_ZENOH_ROUTER_CONFIG.json5 b/rmw_zenoh_cpp/config/DEFAULT_RMW_ZENOH_ROUTER_CONFIG.json5
index f55c8434..cfec676f 100644
--- a/rmw_zenoh_cpp/config/DEFAULT_RMW_ZENOH_ROUTER_CONFIG.json5
+++ b/rmw_zenoh_cpp/config/DEFAULT_RMW_ZENOH_ROUTER_CONFIG.json5
@@ -457,9 +457,7 @@
       /// A probing procedure for shared memory is performed upon session opening. To enable zenoh to operate
       /// over shared memory (and to not fallback on network mode), shared memory needs to be enabled also on the
       /// subscriber side. By doing so, the probing procedure will succeed and shared memory will operate as expected.
-      ///
-      /// ROS setting: disabled by default until fully tested
-      enabled: false,
+      enabled: true,
     },
     auth: {
       /// The configuration of authentication.
diff --git a/rmw_zenoh_cpp/config/DEFAULT_RMW_ZENOH_SESSION_CONFIG.json5 b/rmw_zenoh_cpp/config/DEFAULT_RMW_ZENOH_SESSION_CONFIG.json5
index daffd790..d04aff2d 100644
--- a/rmw_zenoh_cpp/config/DEFAULT_RMW_ZENOH_SESSION_CONFIG.json5
+++ b/rmw_zenoh_cpp/config/DEFAULT_RMW_ZENOH_SESSION_CONFIG.json5
@@ -462,9 +462,7 @@
       /// A probing procedure for shared memory is performed upon session opening. To enable zenoh to operate
       /// over shared memory (and to not fallback on network mode), shared memory needs to be enabled also on the
       /// subscriber side. By doing so, the probing procedure will succeed and shared memory will operate as expected.
-      ///
-      /// ROS setting: disabled by default until fully tested
-      enabled: false,
+      enabled: true,
     },
     auth: {
       /// The configuration of authentication.
diff --git a/rmw_zenoh_cpp/src/detail/rmw_context_impl_s.cpp b/rmw_zenoh_cpp/src/detail/rmw_context_impl_s.cpp
index 8e549394..31ebae10 100644
--- a/rmw_zenoh_cpp/src/detail/rmw_context_impl_s.cpp
+++ b/rmw_zenoh_cpp/src/detail/rmw_context_impl_s.cpp
@@ -90,19 +90,24 @@ rmw_context_impl_s::Data::Data(
   std::size_t domain_id,
   const std::string & enclave,
   z_owned_session_t session,
-  std::optional<z_owned_shm_provider_t> shm_provider,
   const std::string & liveliness_str,
-  std::shared_ptr<rmw_zenoh_cpp::GraphCache> graph_cache)
+  std::shared_ptr<rmw_zenoh_cpp::GraphCache> graph_cache
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+  , std::optional<rmw_zenoh_cpp::ShmContext> shm
+#endif
+  )
 : enclave_(std::move(enclave)),
   domain_id_(std::move(domain_id)),
   session_(std::move(session)),
-  shm_provider_(std::move(shm_provider)),
   liveliness_str_(std::move(liveliness_str)),
   graph_cache_(std::move(graph_cache)),
   is_shutdown_(false),
   next_entity_id_(0),
   is_initialized_(false),
   nodes_({})
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+  , shm_(shm)
+#endif
 {
   graph_guard_condition_ = std::make_unique<rmw_guard_condition_t>();
   graph_guard_condition_->implementation_identifier = rmw_zenoh_cpp::rmw_zenoh_identifier;
@@ -178,14 +183,18 @@ rmw_ret_t rmw_context_impl_s::Data::shutdown()
   }
 
   z_undeclare_subscriber(z_move(graph_subscriber_));
-  if (shm_provider_.has_value()) {
-    z_drop(z_move(shm_provider_.value()));
-  }
+  
   // Don't touch Zenoh Session if the ROS process is exiting,
   // it will cause panic.
   if (!is_exiting) {
     z_close(z_loan_mut(session_), NULL);
   }
+
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+  // drop SHM subsystem if used
+  shm_ = std::nullopt;
+#endif
+
   is_shutdown_ = true;
   return RMW_RET_OK;
 }
@@ -214,14 +223,6 @@ rmw_context_impl_s::rmw_context_impl_s(
     throw std::runtime_error("Error configuring Zenoh session.");
   }
 
-  // Check if shm is enabled.
-  z_owned_string_t shm_enabled;
-  zc_config_get_from_str(z_loan(config), Z_CONFIG_SHARED_MEMORY_KEY, &shm_enabled);
-  auto always_free_shm_enabled = rcpputils::make_scope_exit(
-    [&shm_enabled]() {
-      z_drop(z_move(shm_enabled));
-    });
-
   // Initialize the zenoh session.
   z_owned_session_t session;
   if (z_open(&session, z_move(config), NULL) != Z_OK) {
@@ -309,40 +310,51 @@ rmw_context_impl_s::rmw_context_impl_s(
   }
   z_drop(z_move(handler));
 
-  // Initialize the shm manager if shared_memory is enabled in the config.
-  std::optional<z_owned_shm_provider_t> shm_provider = std::nullopt;
-  if (strncmp(z_string_data(z_loan(shm_enabled)), "true", z_string_len(z_loan(shm_enabled))) == 0) {
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+  // Initialize the shm subsystem if shared_memory is enabled in the config
+  std::optional<rmw_zenoh_cpp::ShmContext> shm;
+  if (rmw_zenoh_cpp::zenoh_shm_enabled()) {
     RMW_ZENOH_LOG_DEBUG_NAMED("rmw_zenoh_cpp", "SHM is enabled");
 
-    // TODO(yuyuan): determine the default alignment of SHM
-    z_alloc_alignment_t alignment = {5};
-    z_owned_memory_layout_t layout;
-    z_memory_layout_new(&layout, SHM_BUFFER_SIZE_MB * 1024 * 1024, alignment);
+    rmw_zenoh_cpp::ShmContext shm_context;
 
-    z_owned_shm_provider_t provider;
-    if (z_posix_shm_provider_new(&provider, z_loan(layout)) != Z_OK) {
-      RMW_ZENOH_LOG_ERROR_NAMED("rmw_zenoh_cpp", "Unable to create a SHM provider.");
-      throw std::runtime_error("Unable to create shm manager.");
+    // Read msg size treshold from config
+    shm_context.msgsize_threshold = rmw_zenoh_cpp::zenoh_shm_message_size_threshold();
+    
+    // Create Layout for provider's memory
+    // Provider's alignment will be 1 byte as we are going to make only 1-byte aligned allocations
+    // TODO(yellowhatter): use zenoh_shm_message_size_threshold as base for alignment
+    z_alloc_alignment_t alignment = {0};
+    z_owned_memory_layout_t layout;
+    if (z_memory_layout_new(&layout, rmw_zenoh_cpp::zenoh_shm_alloc_size(), alignment) != Z_OK) {
+      throw std::runtime_error("Unable to create a Layout for SHM provider.");
+    }
+    // Create SHM provider
+    const auto provider_creation_result =
+      z_posix_shm_provider_new(&shm_context.shm_provider, z_loan(layout));
+    z_drop(z_move(layout));
+    if (provider_creation_result != Z_OK) {
+      throw std::runtime_error("Unable to create an SHM provider.");
     }
-    shm_provider = provider;
+    // Upon successful provider creation, store it in the context
+    shm = std::make_optional(std::move(shm_context));
+  } else {
+    RMW_ZENOH_LOG_DEBUG_NAMED("rmw_zenoh_cpp", "SHM is disabled");
   }
-  auto free_shm_provider = rcpputils::make_scope_exit(
-    [&shm_provider]() {
-      if (shm_provider.has_value()) {
-        z_drop(z_move(shm_provider.value()));
-      }
-    });
+#endif
 
   close_session.cancel();
-  free_shm_provider.cancel();
 
   data_ = std::make_shared<Data>(
     domain_id,
     std::move(enclave),
     std::move(session),
-    std::move(shm_provider),
     std::move(liveliness_str),
-    std::move(graph_cache));
+    std::move(graph_cache)
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+    , std::move(shm)
+#endif
+    );
 
   ret = data_->subscribe_to_ros_graph();
   if (ret != RMW_RET_OK) {
@@ -376,11 +388,13 @@ const z_loaned_session_t * rmw_context_impl_s::session() const
 }
 
 ///=============================================================================
-std::optional<z_owned_shm_provider_t> & rmw_context_impl_s::shm_provider()
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+std::optional<rmw_zenoh_cpp::ShmContext>& rmw_context_impl_s::shm()
 {
   std::lock_guard<std::recursive_mutex> lock(data_->mutex_);
-  return data_->shm_provider_;
+  return data_->shm_;
 }
+#endif
 
 ///=============================================================================
 rmw_guard_condition_t * rmw_context_impl_s::graph_guard_condition()
diff --git a/rmw_zenoh_cpp/src/detail/rmw_context_impl_s.hpp b/rmw_zenoh_cpp/src/detail/rmw_context_impl_s.hpp
index c68aa44c..2f48f8a5 100644
--- a/rmw_zenoh_cpp/src/detail/rmw_context_impl_s.hpp
+++ b/rmw_zenoh_cpp/src/detail/rmw_context_impl_s.hpp
@@ -50,11 +50,13 @@ class rmw_context_impl_s final
   // create other Zenoh objects.
   const z_loaned_session_t * session() const;
 
-  // Get a reference to the shm_provider.
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+  // Get a reference to the shm subsystem.
   // Note: This is not thread-safe.
   // TODO(Yadunund): Remove this API and instead include a publish() API
   // that handles the shm_provider once the context manages publishers.
-  std::optional<z_owned_shm_provider_t> & shm_provider();
+  std::optional<rmw_zenoh_cpp::ShmContext>& shm();
+#endif
 
   // Get the graph guard condition.
   rmw_guard_condition_t * graph_guard_condition();
@@ -103,9 +105,12 @@ class rmw_context_impl_s final
       std::size_t domain_id,
       const std::string & enclave,
       z_owned_session_t session,
-      std::optional<z_owned_shm_provider_t> shm_provider,
       const std::string & liveliness_str,
-      std::shared_ptr<rmw_zenoh_cpp::GraphCache> graph_cache);
+      std::shared_ptr<rmw_zenoh_cpp::GraphCache> graph_cache
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+      , std::optional<rmw_zenoh_cpp::ShmContext> shm
+#endif
+    );
 
     // Subscribe to the ROS graph.
     rmw_ret_t subscribe_to_ros_graph();
@@ -126,9 +131,6 @@ class rmw_context_impl_s final
     std::size_t domain_id_;
     // An owned session.
     z_owned_session_t session_;
-    // An optional SHM manager that is initialized of SHM is enabled in the
-    // zenoh session config.
-    std::optional<z_owned_shm_provider_t> shm_provider_;
     // Liveliness keyexpr string to subscribe to for ROS graph changes.
     std::string liveliness_str_;
     // Graph cache.
@@ -148,6 +150,11 @@ class rmw_context_impl_s final
     bool is_initialized_;
     // Nodes created from this context.
     std::unordered_map<const rmw_node_t *, std::shared_ptr<rmw_zenoh_cpp::NodeData>> nodes_;
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+    // An optional SHM context that is initialized if SHM is enabled in the
+    // zenoh session config.
+    std::optional<rmw_zenoh_cpp::ShmContext> shm_;
+#endif
   };
 
   std::shared_ptr<Data> data_{nullptr};
diff --git a/rmw_zenoh_cpp/src/detail/rmw_publisher_data.cpp b/rmw_zenoh_cpp/src/detail/rmw_publisher_data.cpp
index a3b78a3d..20d7fb2d 100644
--- a/rmw_zenoh_cpp/src/detail/rmw_publisher_data.cpp
+++ b/rmw_zenoh_cpp/src/detail/rmw_publisher_data.cpp
@@ -223,8 +223,11 @@ PublisherData::PublisherData(
 
 ///=============================================================================
 rmw_ret_t PublisherData::publish(
-  const void * ros_message,
-  std::optional<z_owned_shm_provider_t> & shm_provider)
+  const void * ros_message
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+  , std::optional<ShmContext> & shm
+#endif
+  )
 {
   std::lock_guard<std::mutex> lock(mutex_);
   if (is_shutdown_) {
@@ -233,12 +236,14 @@ rmw_ret_t PublisherData::publish(
   }
 
   // Serialize data.
-  size_t max_data_length = type_support_->get_estimated_serialized_size(
+  const size_t max_data_length = type_support_->get_estimated_serialized_size(
     ros_message,
     type_support_impl_);
 
   // To store serialized message byte array.
   char * msg_bytes = nullptr;
+
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
   std::optional<z_owned_shm_mut_t> shmbuf = std::nullopt;
   auto always_free_shmbuf = rcpputils::make_scope_exit(
     [&shmbuf]() {
@@ -246,24 +251,35 @@ rmw_ret_t PublisherData::publish(
         z_drop(z_move(shmbuf.value()));
       }
     });
+#endif
 
   rcutils_allocator_t * allocator = &rmw_node_->context->options.allocator;
 
   auto always_free_msg_bytes = rcpputils::make_scope_exit(
-    [&msg_bytes, allocator, &shmbuf]() {
-      if (msg_bytes && !shmbuf.has_value()) {
+    [&msg_bytes, allocator
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+     , &shmbuf
+#endif
+    ]() {
+      if (msg_bytes 
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+          && !shmbuf.has_value()
+#endif
+      ) {
         allocator->deallocate(msg_bytes, allocator->state);
       }
     });
 
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
   // Get memory from SHM buffer if available.
-  if (shm_provider.has_value()) {
+  if (shm.has_value() && max_data_length >= shm.value().msgsize_threshold) {
     RMW_ZENOH_LOG_DEBUG_NAMED("rmw_zenoh_cpp", "SHM is enabled.");
 
-    auto provider = shm_provider.value();
+    auto& provider = shm.value().shm_provider;
+
+    // TODO(yellowhatter): SHM, use alignment based on msgsize_threshold
+    z_alloc_alignment_t alignment = {0};
     z_buf_layout_alloc_result_t alloc;
-    // TODO(yuyuan): SHM, configure this
-    z_alloc_alignment_t alignment = {5};
     z_shm_provider_alloc_gc_defrag_blocking(&alloc, z_loan(provider), SHM_BUF_OK_SIZE, alignment);
 
     if (alloc.status == ZC_BUF_LAYOUT_ALLOC_STATUS_OK) {
@@ -274,7 +290,9 @@ rmw_ret_t PublisherData::publish(
       RMW_SET_ERROR_MSG("Failed to allocate a SHM buffer, even after GCing.");
       return RMW_RET_ERROR;
     }
-  } else {
+  } else
+#endif
+  {
     // Get memory from the allocator.
     msg_bytes = static_cast<char *>(allocator->allocate(max_data_length, allocator->state));
     RMW_CHECK_FOR_NULL_WITH_MSG(
@@ -309,9 +327,12 @@ rmw_ret_t PublisherData::publish(
   options.attachment = z_move(attachment);
 
   z_owned_bytes_t payload;
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
   if (shmbuf.has_value()) {
     z_bytes_from_shm_mut(&payload, z_move(shmbuf.value()));
-  } else {
+  } else
+#endif
+  {
     z_bytes_copy_from_buf(&payload, reinterpret_cast<const uint8_t *>(msg_bytes), data_length);
   }
 
@@ -332,8 +353,11 @@ rmw_ret_t PublisherData::publish(
 
 ///=============================================================================
 rmw_ret_t PublisherData::publish_serialized_message(
-  const rmw_serialized_message_t * serialized_message,
-  std::optional<z_owned_shm_provider_t> & /*shm_provider*/)
+  const rmw_serialized_message_t * serialized_message
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+  , std::optional<ShmContext> & /*shm_provider*/
+#endif
+  )
 {
   eprosima::fastcdr::FastBuffer buffer(
     reinterpret_cast<char *>(serialized_message->buffer), serialized_message->buffer_length);
diff --git a/rmw_zenoh_cpp/src/detail/rmw_publisher_data.hpp b/rmw_zenoh_cpp/src/detail/rmw_publisher_data.hpp
index 56767ca4..29db7d63 100644
--- a/rmw_zenoh_cpp/src/detail/rmw_publisher_data.hpp
+++ b/rmw_zenoh_cpp/src/detail/rmw_publisher_data.hpp
@@ -27,6 +27,7 @@
 #include "event.hpp"
 #include "liveliness_utils.hpp"
 #include "message_type_support.hpp"
+#include "shm_context.hpp"
 
 #include "rmw/ret_types.h"
 
@@ -49,13 +50,19 @@ class PublisherData final
 
   // Publish a ROS message.
   rmw_ret_t publish(
-    const void * ros_message,
-    std::optional<z_owned_shm_provider_t> & shm_provider);
+    const void * ros_message
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+  , std::optional<ShmContext> & shm
+#endif
+  );
 
   // Publish a serialized ROS message.
   rmw_ret_t publish_serialized_message(
-    const rmw_serialized_message_t * serialized_message,
-    std::optional<z_owned_shm_provider_t> & shm_provider);
+    const rmw_serialized_message_t * serialized_message
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+  , std::optional<ShmContext> & shm
+#endif
+  );
 
   // Get a copy of the keyexpr_hash of this PublisherData's liveliness::Entity.
   std::size_t keyexpr_hash() const;
diff --git a/rmw_zenoh_cpp/src/detail/rmw_subscription_data.hpp b/rmw_zenoh_cpp/src/detail/rmw_subscription_data.hpp
index 9f9f8c02..5abca54c 100644
--- a/rmw_zenoh_cpp/src/detail/rmw_subscription_data.hpp
+++ b/rmw_zenoh_cpp/src/detail/rmw_subscription_data.hpp
@@ -34,6 +34,7 @@
 #include "message_type_support.hpp"
 #include "attachment_helpers.hpp"
 #include "type_support_common.hpp"
+#include "shm_context.hpp"
 
 #include "rcutils/allocator.h"
 
@@ -74,8 +75,11 @@ class SubscriptionData final : public std::enable_shared_from_this<SubscriptionD
 
   // Publish a ROS message.
   rmw_ret_t publish(
-    const void * ros_message,
-    std::optional<z_owned_shm_provider_t> & shm_provider);
+    const void * ros_message
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+  , std::optional<ShmContext> & shm
+#endif
+  );
 
   // Get a copy of the keyexpr_hash of this SubscriptionData's liveliness::Entity.
   std::size_t keyexpr_hash() const;
diff --git a/rmw_zenoh_cpp/src/detail/shm_context.cpp b/rmw_zenoh_cpp/src/detail/shm_context.cpp
new file mode 100644
index 00000000..8dcf8566
--- /dev/null
+++ b/rmw_zenoh_cpp/src/detail/shm_context.cpp
@@ -0,0 +1,26 @@
+// Copyright 2023 Open Source Robotics Foundation, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "shm_context.hpp"
+
+namespace rmw_zenoh_cpp
+{
+///=============================================================================
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+ShmContext::~ShmContext()
+{
+  z_drop(z_move(shm_provider));
+}
+#endif
+}  // namespace rmw_zenoh_cpp
diff --git a/rmw_zenoh_cpp/src/detail/shm_context.hpp b/rmw_zenoh_cpp/src/detail/shm_context.hpp
new file mode 100644
index 00000000..4db7bcbd
--- /dev/null
+++ b/rmw_zenoh_cpp/src/detail/shm_context.hpp
@@ -0,0 +1,33 @@
+// Copyright 2023 Open Source Robotics Foundation, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef DETAIL__SHM_CONTEXT_HPP_
+#define DETAIL__SHM_CONTEXT_HPP_
+
+
+namespace rmw_zenoh_cpp
+{
+///=============================================================================
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+    struct ShmContext
+    {
+      z_owned_shm_provider_t shm_provider;
+      size_t msgsize_threshold;
+
+      ~ShmContext();
+    };
+#endif
+}  // namespace rmw_zenoh_cpp
+
+#endif  // DETAIL__SHM_CONTEXT_HPP_
diff --git a/rmw_zenoh_cpp/src/detail/zenoh_config.cpp b/rmw_zenoh_cpp/src/detail/zenoh_config.cpp
index 206e2a92..d0ecce86 100644
--- a/rmw_zenoh_cpp/src/detail/zenoh_config.cpp
+++ b/rmw_zenoh_cpp/src/detail/zenoh_config.cpp
@@ -42,6 +42,14 @@ static const std::unordered_map<ConfigurableEntity,
 };
 
 static const char * router_check_attempts_envar = "ZENOH_ROUTER_CHECK_ATTEMPTS";
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+static const char * zenoh_shm_enabled_envar = "ZENOH_SHM_ENABLED";
+static const bool zenoh_shm_enabled_default = true;
+static const char * zenoh_shm_alloc_size_envar = "ZENOH_SHM_ALLOC_SIZE";
+static const size_t zenoh_shm_alloc_size_default = 1 * 1024 * 1024;
+static const char * zenoh_shm_message_size_threshold_envar = "ZENOH_SHM_MESSAGE_SIZE_THRESHOLD";
+static const size_t zenoh_shm_message_size_threshold_default = 2 * 1024;
+#endif
 
 rmw_ret_t _get_z_config(
   const char * envar_name,
@@ -123,4 +131,90 @@ std::optional<uint64_t> zenoh_router_check_attempts()
   // If unset, check indefinitely.
   return default_value;
 }
+
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+///=============================================================================
+bool zenoh_shm_enabled()
+{
+  const char * envar_value;
+
+  if (NULL != rcutils_get_env(zenoh_shm_enabled_envar, &envar_value)) {
+    RMW_ZENOH_LOG_ERROR_NAMED(
+      "rmw_zenoh_cpp", "Envar %s cannot be read. Report this bug.",
+      zenoh_shm_enabled_envar);
+    return zenoh_shm_enabled_default;
+  }
+
+  if (strncmp(envar_value, "false", strlen(envar_value)) == 0) {
+    return false;
+  }
+
+  if (strncmp(envar_value, "true", strlen(envar_value)) == 0) {
+    return true;
+  }
+
+  return zenoh_shm_enabled_default;
+}
+///=============================================================================
+size_t zenoh_shm_alloc_size()
+{
+  const char * envar_value;
+
+  if (NULL != rcutils_get_env(zenoh_shm_alloc_size_envar, &envar_value)) {
+    RMW_ZENOH_LOG_ERROR_NAMED(
+      "rmw_zenoh_cpp", "Envar %s cannot be read. Report this bug.",
+      zenoh_shm_alloc_size_envar);
+    return zenoh_shm_alloc_size_default;
+  }
+
+  // If the environment variable contains a value, handle it accordingly.
+  if (envar_value[0] != '\0') {
+    const auto read_value = std::strtoull(envar_value, nullptr, 10);
+    if (read_value > 0) {
+      if (read_value > std::numeric_limits<size_t>::max()) {
+        RMW_ZENOH_LOG_ERROR_NAMED(
+          "rmw_zenoh_cpp", "Envar %s: value is too large!",
+          zenoh_shm_alloc_size_envar);
+      } else {
+        return read_value;
+      }
+    }
+  }
+
+  return zenoh_shm_alloc_size_default;
+}
+///=============================================================================
+size_t zenoh_shm_message_size_threshold()
+{
+  const char * envar_value;
+
+  if (NULL != rcutils_get_env(zenoh_shm_message_size_threshold_envar, &envar_value)) {
+    RMW_ZENOH_LOG_ERROR_NAMED(
+      "rmw_zenoh_cpp", "Envar %s cannot be read. Report this bug.",
+      zenoh_shm_message_size_threshold_envar);
+    return zenoh_shm_message_size_threshold_default;
+  }
+
+  // If the environment variable contains a value, handle it accordingly.
+  if (envar_value[0] != '\0') {
+    const auto read_value = std::strtoull(envar_value, nullptr, 10);
+    if (read_value > 0) {
+      if (read_value > std::numeric_limits<size_t>::max()) {
+        RMW_ZENOH_LOG_ERROR_NAMED(
+          "rmw_zenoh_cpp", "Envar %s: value is too large!",
+          zenoh_shm_message_size_threshold_envar);
+      } else if ((read_value & (read_value - 1)) != 0) { // power of 2 check
+        RMW_ZENOH_LOG_ERROR_NAMED(
+          "rmw_zenoh_cpp", "Envar %s: value must be power of 2!",
+          zenoh_shm_message_size_threshold_envar);
+
+      } else {
+        return read_value;
+      }
+    }
+  }
+
+  return zenoh_shm_message_size_threshold_default;
+}
+#endif
 }  // namespace rmw_zenoh_cpp
diff --git a/rmw_zenoh_cpp/src/detail/zenoh_config.hpp b/rmw_zenoh_cpp/src/detail/zenoh_config.hpp
index 357c7e89..57aa657d 100644
--- a/rmw_zenoh_cpp/src/detail/zenoh_config.hpp
+++ b/rmw_zenoh_cpp/src/detail/zenoh_config.hpp
@@ -57,6 +57,36 @@ rmw_ret_t get_z_config(const ConfigurableEntity & entity, z_owned_config_t * con
 /// @return The number of times to try connecting to a zenoh router and
 ///   std::nullopt if establishing a connection to a router is not required.
 std::optional<uint64_t> zenoh_router_check_attempts();
+
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+///=============================================================================
+/// Get the enabled state of shared memory subsystem
+/// based on the environment variable ZENOH_SHM_ENABLED.
+/// @details The behavior is as follows:
+///   - If not set or not "false", the default value of "true" is returned.
+///   - Else "false" is returned.
+/// @return The amount of shared memory to be pre-allocated for Zenoh SHM operation
+bool zenoh_shm_enabled();
+
+///=============================================================================
+/// Get the amount of shared memory to be pre-allocated for Zenoh SHM operation
+/// based on the environment variable ZENOH_SHM_ALLOC_SIZE.
+/// @details The behavior is as follows:
+///   - If not set or <= 0, the default value of 1MB is returned.
+///   - Else value of environemnt variable is returned.
+/// @return The amount of shared memory to be pre-allocated for Zenoh SHM operation
+size_t zenoh_shm_alloc_size();
+
+///=============================================================================
+/// Message size threshold for implicit SHM optimization based on the environment
+/// variable ZENOH_SHM_MESSAGE_SIZE_THRESHOLD.
+/// Messages smaller than this threshold will not be forwarded through Zenoh SHM
+/// @details The behavior is as follows:
+///   - If not set or <= 0, the default value of 2KB is returned.
+///   - Else value of environemnt variable is returned.
+/// @return The amount of shared memory to be pre-allocated for Zenoh SHM operation
+size_t zenoh_shm_message_size_threshold();
+#endif
 }  // namespace rmw_zenoh_cpp
 
 #endif  // DETAIL__ZENOH_CONFIG_HPP_
diff --git a/rmw_zenoh_cpp/src/rmw_zenoh.cpp b/rmw_zenoh_cpp/src/rmw_zenoh.cpp
index 25b2e02c..08384df4 100644
--- a/rmw_zenoh_cpp/src/rmw_zenoh.cpp
+++ b/rmw_zenoh_cpp/src/rmw_zenoh.cpp
@@ -598,8 +598,11 @@ rmw_publish(
   }
 
   return pub_data->publish(
-    ros_message,
-    context_impl->shm_provider());
+    ros_message
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+    , context_impl->shm()
+#endif
+    );
 }
 
 //==============================================================================
@@ -705,8 +708,11 @@ rmw_publish_serialized_message(
   RMW_CHECK_ARGUMENT_FOR_NULL(publisher_data, RMW_RET_INVALID_ARGUMENT);
 
   return publisher_data->publish_serialized_message(
-    serialized_message,
-    context_impl->shm_provider());
+    serialized_message
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+    , context_impl->shm()
+#endif
+    );
 }
 
 //==============================================================================
diff --git a/zenoh_c_vendor/CMakeLists.txt b/zenoh_c_vendor/CMakeLists.txt
index ded765de..2424de29 100644
--- a/zenoh_c_vendor/CMakeLists.txt
+++ b/zenoh_c_vendor/CMakeLists.txt
@@ -15,7 +15,9 @@ find_package(ament_cmake_vendor_package REQUIRED)
 # Note: We separate the two args needed for cargo with "$<SEMICOLON>" and not ";" as the
 # latter is a list separater in cmake and hence the string will be split into two
 # when expanded.
-set(ZENOHC_CARGO_FLAGS "--no-default-features$<SEMICOLON>--features=shared-memory zenoh/transport_compression zenoh/transport_tcp zenoh/transport_tls")
+set(ZENOHC_CARGO_FLAGS "--no-default-features$<SEMICOLON>--features=zenoh/transport_compression zenoh/transport_tcp zenoh/transport_tls")
+
+set(RMW_ZENOH_BUILD_WITH_SHARED_MEMORY OFF CACHE BOOL "Compile Zenoh RMW with Shared Memory support")
 
 # Set VCS_VERSION to include latest changes from zenoh-c to benefit from :
 # - https://github.com/eclipse-zenoh/zenoh-c/pull/340 (fix build issue)
@@ -29,6 +31,7 @@ ament_vendor(zenoh_c_vendor
   VCS_VERSION a57fda736d2f8866c06509f34b5bc73e372c6aaf
   CMAKE_ARGS
     "-DZENOHC_CARGO_FLAGS=${ZENOHC_CARGO_FLAGS}"
+    "-DZENOHC_BUILD_WITH_SHARED_MEMORY=${RMW_ZENOH_BUILD_WITH_SHARED_MEMORY}"
     "-DZENOHC_BUILD_WITH_UNSTABLE_API=TRUE"
     "-DZENOHC_CUSTOM_TARGET=${ZENOHC_CUSTOM_TARGET}"
 )

From 016fdde59d7452360109fc86a0bf6250099fd026 Mon Sep 17 00:00:00 2001
From: yellowhatter <bannov.dy@gmail.com>
Date: Tue, 12 Nov 2024 23:48:45 +0300
Subject: [PATCH 2/8] add .gitignore

---
 .gitignore | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 .gitignore

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 00000000..722d5e71
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+.vscode

From 0b3b7dc5c3428c1ed4c0bb1bc53ed4c0935738be Mon Sep 17 00:00:00 2001
From: yellowhatter <bannov.dy@gmail.com>
Date: Tue, 12 Nov 2024 23:55:09 +0300
Subject: [PATCH 3/8] ament_uncrustify

---
 rmw_zenoh_cpp/src/detail/rmw_context_impl_s.cpp | 10 +++++-----
 rmw_zenoh_cpp/src/detail/rmw_context_impl_s.hpp |  2 +-
 rmw_zenoh_cpp/src/detail/rmw_publisher_data.cpp | 13 +++++++------
 rmw_zenoh_cpp/src/detail/shm_context.hpp        | 12 ++++++------
 rmw_zenoh_cpp/src/rmw_zenoh.cpp                 |  4 ++--
 5 files changed, 21 insertions(+), 20 deletions(-)

diff --git a/rmw_zenoh_cpp/src/detail/rmw_context_impl_s.cpp b/rmw_zenoh_cpp/src/detail/rmw_context_impl_s.cpp
index 31ebae10..4b77e031 100644
--- a/rmw_zenoh_cpp/src/detail/rmw_context_impl_s.cpp
+++ b/rmw_zenoh_cpp/src/detail/rmw_context_impl_s.cpp
@@ -95,7 +95,7 @@ rmw_context_impl_s::Data::Data(
 #ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
   , std::optional<rmw_zenoh_cpp::ShmContext> shm
 #endif
-  )
+)
 : enclave_(std::move(enclave)),
   domain_id_(std::move(domain_id)),
   session_(std::move(session)),
@@ -183,7 +183,7 @@ rmw_ret_t rmw_context_impl_s::Data::shutdown()
   }
 
   z_undeclare_subscriber(z_move(graph_subscriber_));
-  
+
   // Don't touch Zenoh Session if the ROS process is exiting,
   // it will cause panic.
   if (!is_exiting) {
@@ -320,7 +320,7 @@ rmw_context_impl_s::rmw_context_impl_s(
 
     // Read msg size treshold from config
     shm_context.msgsize_threshold = rmw_zenoh_cpp::zenoh_shm_message_size_threshold();
-    
+
     // Create Layout for provider's memory
     // Provider's alignment will be 1 byte as we are going to make only 1-byte aligned allocations
     // TODO(yellowhatter): use zenoh_shm_message_size_threshold as base for alignment
@@ -354,7 +354,7 @@ rmw_context_impl_s::rmw_context_impl_s(
 #ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
     , std::move(shm)
 #endif
-    );
+  );
 
   ret = data_->subscribe_to_ros_graph();
   if (ret != RMW_RET_OK) {
@@ -389,7 +389,7 @@ const z_loaned_session_t * rmw_context_impl_s::session() const
 
 ///=============================================================================
 #ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
-std::optional<rmw_zenoh_cpp::ShmContext>& rmw_context_impl_s::shm()
+std::optional<rmw_zenoh_cpp::ShmContext> & rmw_context_impl_s::shm()
 {
   std::lock_guard<std::recursive_mutex> lock(data_->mutex_);
   return data_->shm_;
diff --git a/rmw_zenoh_cpp/src/detail/rmw_context_impl_s.hpp b/rmw_zenoh_cpp/src/detail/rmw_context_impl_s.hpp
index 2f48f8a5..c99f5018 100644
--- a/rmw_zenoh_cpp/src/detail/rmw_context_impl_s.hpp
+++ b/rmw_zenoh_cpp/src/detail/rmw_context_impl_s.hpp
@@ -55,7 +55,7 @@ class rmw_context_impl_s final
   // Note: This is not thread-safe.
   // TODO(Yadunund): Remove this API and instead include a publish() API
   // that handles the shm_provider once the context manages publishers.
-  std::optional<rmw_zenoh_cpp::ShmContext>& shm();
+  std::optional<rmw_zenoh_cpp::ShmContext> & shm();
 #endif
 
   // Get the graph guard condition.
diff --git a/rmw_zenoh_cpp/src/detail/rmw_publisher_data.cpp b/rmw_zenoh_cpp/src/detail/rmw_publisher_data.cpp
index 20d7fb2d..7512ac5b 100644
--- a/rmw_zenoh_cpp/src/detail/rmw_publisher_data.cpp
+++ b/rmw_zenoh_cpp/src/detail/rmw_publisher_data.cpp
@@ -227,7 +227,7 @@ rmw_ret_t PublisherData::publish(
 #ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
   , std::optional<ShmContext> & shm
 #endif
-  )
+)
 {
   std::lock_guard<std::mutex> lock(mutex_);
   if (is_shutdown_) {
@@ -258,14 +258,15 @@ rmw_ret_t PublisherData::publish(
   auto always_free_msg_bytes = rcpputils::make_scope_exit(
     [&msg_bytes, allocator
 #ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
-     , &shmbuf
+    , &shmbuf
 #endif
     ]() {
-      if (msg_bytes 
+      if (msg_bytes
 #ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
           && !shmbuf.has_value()
 #endif
-      ) {
+      )
+      {
         allocator->deallocate(msg_bytes, allocator->state);
       }
     });
@@ -275,7 +276,7 @@ rmw_ret_t PublisherData::publish(
   if (shm.has_value() && max_data_length >= shm.value().msgsize_threshold) {
     RMW_ZENOH_LOG_DEBUG_NAMED("rmw_zenoh_cpp", "SHM is enabled.");
 
-    auto& provider = shm.value().shm_provider;
+    auto & provider = shm.value().shm_provider;
 
     // TODO(yellowhatter): SHM, use alignment based on msgsize_threshold
     z_alloc_alignment_t alignment = {0};
@@ -357,7 +358,7 @@ rmw_ret_t PublisherData::publish_serialized_message(
 #ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
   , std::optional<ShmContext> & /*shm_provider*/
 #endif
-  )
+)
 {
   eprosima::fastcdr::FastBuffer buffer(
     reinterpret_cast<char *>(serialized_message->buffer), serialized_message->buffer_length);
diff --git a/rmw_zenoh_cpp/src/detail/shm_context.hpp b/rmw_zenoh_cpp/src/detail/shm_context.hpp
index 4db7bcbd..619afa3e 100644
--- a/rmw_zenoh_cpp/src/detail/shm_context.hpp
+++ b/rmw_zenoh_cpp/src/detail/shm_context.hpp
@@ -20,13 +20,13 @@ namespace rmw_zenoh_cpp
 {
 ///=============================================================================
 #ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
-    struct ShmContext
-    {
-      z_owned_shm_provider_t shm_provider;
-      size_t msgsize_threshold;
+struct ShmContext
+{
+  z_owned_shm_provider_t shm_provider;
+  size_t msgsize_threshold;
 
-      ~ShmContext();
-    };
+  ~ShmContext();
+};
 #endif
 }  // namespace rmw_zenoh_cpp
 
diff --git a/rmw_zenoh_cpp/src/rmw_zenoh.cpp b/rmw_zenoh_cpp/src/rmw_zenoh.cpp
index 728916e2..7cf350c2 100644
--- a/rmw_zenoh_cpp/src/rmw_zenoh.cpp
+++ b/rmw_zenoh_cpp/src/rmw_zenoh.cpp
@@ -602,7 +602,7 @@ rmw_publish(
 #ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
     , context_impl->shm()
 #endif
-    );
+  );
 }
 
 //==============================================================================
@@ -712,7 +712,7 @@ rmw_publish_serialized_message(
 #ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
     , context_impl->shm()
 #endif
-    );
+  );
 }
 
 //==============================================================================

From 48fcef8b9538935cbd41306174a1f428ed66e982 Mon Sep 17 00:00:00 2001
From: yellowhatter <bannov.dy@gmail.com>
Date: Tue, 12 Nov 2024 23:59:57 +0300
Subject: [PATCH 4/8] ament_cpplint

---
 .../src/detail/rmw_publisher_data.cpp         | 20 ++++++++++---------
 rmw_zenoh_cpp/src/detail/zenoh_config.cpp     |  2 +-
 2 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/rmw_zenoh_cpp/src/detail/rmw_publisher_data.cpp b/rmw_zenoh_cpp/src/detail/rmw_publisher_data.cpp
index 7512ac5b..02d40326 100644
--- a/rmw_zenoh_cpp/src/detail/rmw_publisher_data.cpp
+++ b/rmw_zenoh_cpp/src/detail/rmw_publisher_data.cpp
@@ -291,14 +291,15 @@ rmw_ret_t PublisherData::publish(
       RMW_SET_ERROR_MSG("Failed to allocate a SHM buffer, even after GCing.");
       return RMW_RET_ERROR;
     }
-  } else
+  } else {
 #endif
-  {
     // Get memory from the allocator.
-    msg_bytes = static_cast<char *>(allocator->allocate(max_data_length, allocator->state));
-    RMW_CHECK_FOR_NULL_WITH_MSG(
+  msg_bytes = static_cast<char *>(allocator->allocate(max_data_length, allocator->state));
+  RMW_CHECK_FOR_NULL_WITH_MSG(
       msg_bytes, "bytes for message is null", return RMW_RET_BAD_ALLOC);
-  }
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+}
+#endif
 
   // Object that manages the raw buffer
   eprosima::fastcdr::FastBuffer fastbuffer(msg_bytes, max_data_length);
@@ -331,11 +332,12 @@ rmw_ret_t PublisherData::publish(
 #ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
   if (shmbuf.has_value()) {
     z_bytes_from_shm_mut(&payload, z_move(shmbuf.value()));
-  } else
+  } else {
+#endif
+  z_bytes_copy_from_buf(&payload, reinterpret_cast<const uint8_t *>(msg_bytes), data_length);
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+}
 #endif
-  {
-    z_bytes_copy_from_buf(&payload, reinterpret_cast<const uint8_t *>(msg_bytes), data_length);
-  }
 
   z_result_t res = z_publisher_put(z_loan(pub_), z_move(payload), &options);
   if (res != Z_OK) {
diff --git a/rmw_zenoh_cpp/src/detail/zenoh_config.cpp b/rmw_zenoh_cpp/src/detail/zenoh_config.cpp
index d0ecce86..9429b145 100644
--- a/rmw_zenoh_cpp/src/detail/zenoh_config.cpp
+++ b/rmw_zenoh_cpp/src/detail/zenoh_config.cpp
@@ -203,7 +203,7 @@ size_t zenoh_shm_message_size_threshold()
         RMW_ZENOH_LOG_ERROR_NAMED(
           "rmw_zenoh_cpp", "Envar %s: value is too large!",
           zenoh_shm_message_size_threshold_envar);
-      } else if ((read_value & (read_value - 1)) != 0) { // power of 2 check
+      } else if ((read_value & (read_value - 1)) != 0) {  // power of 2 check
         RMW_ZENOH_LOG_ERROR_NAMED(
           "rmw_zenoh_cpp", "Envar %s: value must be power of 2!",
           zenoh_shm_message_size_threshold_envar);

From f314501cf730a4b5bce3ce14a558865c8cd4474e Mon Sep 17 00:00:00 2001
From: yellowhatter <bannov.dy@gmail.com>
Date: Wed, 13 Nov 2024 00:30:32 +0300
Subject: [PATCH 5/8] uncrustify

---
 rmw_zenoh_cpp/src/detail/rmw_publisher_data.cpp | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/rmw_zenoh_cpp/src/detail/rmw_publisher_data.cpp b/rmw_zenoh_cpp/src/detail/rmw_publisher_data.cpp
index 02d40326..dfac42f4 100644
--- a/rmw_zenoh_cpp/src/detail/rmw_publisher_data.cpp
+++ b/rmw_zenoh_cpp/src/detail/rmw_publisher_data.cpp
@@ -263,7 +263,7 @@ rmw_ret_t PublisherData::publish(
     ]() {
       if (msg_bytes
 #ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
-          && !shmbuf.has_value()
+      && !shmbuf.has_value()
 #endif
       )
       {
@@ -293,10 +293,10 @@ rmw_ret_t PublisherData::publish(
     }
   } else {
 #endif
-    // Get memory from the allocator.
+  // Get memory from the allocator.
   msg_bytes = static_cast<char *>(allocator->allocate(max_data_length, allocator->state));
   RMW_CHECK_FOR_NULL_WITH_MSG(
-      msg_bytes, "bytes for message is null", return RMW_RET_BAD_ALLOC);
+    msg_bytes, "bytes for message is null", return RMW_RET_BAD_ALLOC);
 #ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
 }
 #endif

From 388d8c65c5bf0ae9bc00727e95579f3c4b37a0ff Mon Sep 17 00:00:00 2001
From: yellowhatter <bannov.dy@gmail.com>
Date: Wed, 13 Nov 2024 00:44:15 +0300
Subject: [PATCH 6/8] code format fixes

---
 rmw_zenoh_cpp/src/detail/rmw_publisher_data.hpp    | 4 ++--
 rmw_zenoh_cpp/src/detail/rmw_subscription_data.hpp | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/rmw_zenoh_cpp/src/detail/rmw_publisher_data.hpp b/rmw_zenoh_cpp/src/detail/rmw_publisher_data.hpp
index 29db7d63..eca222b7 100644
--- a/rmw_zenoh_cpp/src/detail/rmw_publisher_data.hpp
+++ b/rmw_zenoh_cpp/src/detail/rmw_publisher_data.hpp
@@ -52,7 +52,7 @@ class PublisherData final
   rmw_ret_t publish(
     const void * ros_message
 #ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
-  , std::optional<ShmContext> & shm
+    , std::optional<ShmContext> & shm
 #endif
   );
 
@@ -60,7 +60,7 @@ class PublisherData final
   rmw_ret_t publish_serialized_message(
     const rmw_serialized_message_t * serialized_message
 #ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
-  , std::optional<ShmContext> & shm
+    , std::optional<ShmContext> & shm
 #endif
   );
 
diff --git a/rmw_zenoh_cpp/src/detail/rmw_subscription_data.hpp b/rmw_zenoh_cpp/src/detail/rmw_subscription_data.hpp
index 5abca54c..4f864994 100644
--- a/rmw_zenoh_cpp/src/detail/rmw_subscription_data.hpp
+++ b/rmw_zenoh_cpp/src/detail/rmw_subscription_data.hpp
@@ -77,7 +77,7 @@ class SubscriptionData final : public std::enable_shared_from_this<SubscriptionD
   rmw_ret_t publish(
     const void * ros_message
 #ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
-  , std::optional<ShmContext> & shm
+    , std::optional<ShmContext> & shm
 #endif
   );
 

From 5643258db473521986a60ee11921805c368a3d32 Mon Sep 17 00:00:00 2001
From: yellowhatter <bannov.dy@gmail.com>
Date: Wed, 13 Nov 2024 13:41:31 +0300
Subject: [PATCH 7/8] build with SHM by default to align with other rmw impls

---
 rmw_zenoh_cpp/CMakeLists.txt  | 2 +-
 zenoh_c_vendor/CMakeLists.txt | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/rmw_zenoh_cpp/CMakeLists.txt b/rmw_zenoh_cpp/CMakeLists.txt
index 23b1115d..7d8db9dd 100644
--- a/rmw_zenoh_cpp/CMakeLists.txt
+++ b/rmw_zenoh_cpp/CMakeLists.txt
@@ -11,7 +11,7 @@ if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
   add_compile_options(-Wall -Wextra -Wpedantic)
 endif()
 
-set(RMW_ZENOH_BUILD_WITH_SHARED_MEMORY OFF CACHE BOOL "Compile Zenoh RMW with Shared Memory support")
+set(RMW_ZENOH_BUILD_WITH_SHARED_MEMORY ON CACHE BOOL "Compile Zenoh RMW with Shared Memory support")
 
 # find dependencies
 find_package(ament_cmake REQUIRED)
diff --git a/zenoh_c_vendor/CMakeLists.txt b/zenoh_c_vendor/CMakeLists.txt
index 2424de29..54401dd4 100644
--- a/zenoh_c_vendor/CMakeLists.txt
+++ b/zenoh_c_vendor/CMakeLists.txt
@@ -17,7 +17,7 @@ find_package(ament_cmake_vendor_package REQUIRED)
 # when expanded.
 set(ZENOHC_CARGO_FLAGS "--no-default-features$<SEMICOLON>--features=zenoh/transport_compression zenoh/transport_tcp zenoh/transport_tls")
 
-set(RMW_ZENOH_BUILD_WITH_SHARED_MEMORY OFF CACHE BOOL "Compile Zenoh RMW with Shared Memory support")
+set(RMW_ZENOH_BUILD_WITH_SHARED_MEMORY ON CACHE BOOL "Compile Zenoh RMW with Shared Memory support")
 
 # Set VCS_VERSION to include latest changes from zenoh-c to benefit from :
 # - https://github.com/eclipse-zenoh/zenoh-c/pull/340 (fix build issue)

From 498c2114510da8f06d81fd06b97a9e299b4c8086 Mon Sep 17 00:00:00 2001
From: yuanyuyuan <az6980522@gmail.com>
Date: Thu, 14 Nov 2024 00:39:46 +0800
Subject: [PATCH 8/8] refactor: disable shared-memory in the config since it
 hasn't been tested

---
 rmw_zenoh_cpp/config/DEFAULT_RMW_ZENOH_ROUTER_CONFIG.json5  | 2 +-
 rmw_zenoh_cpp/config/DEFAULT_RMW_ZENOH_SESSION_CONFIG.json5 | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/rmw_zenoh_cpp/config/DEFAULT_RMW_ZENOH_ROUTER_CONFIG.json5 b/rmw_zenoh_cpp/config/DEFAULT_RMW_ZENOH_ROUTER_CONFIG.json5
index cfec676f..25e065dc 100644
--- a/rmw_zenoh_cpp/config/DEFAULT_RMW_ZENOH_ROUTER_CONFIG.json5
+++ b/rmw_zenoh_cpp/config/DEFAULT_RMW_ZENOH_ROUTER_CONFIG.json5
@@ -457,7 +457,7 @@
       /// A probing procedure for shared memory is performed upon session opening. To enable zenoh to operate
       /// over shared memory (and to not fallback on network mode), shared memory needs to be enabled also on the
       /// subscriber side. By doing so, the probing procedure will succeed and shared memory will operate as expected.
-      enabled: true,
+      enabled: false,
     },
     auth: {
       /// The configuration of authentication.
diff --git a/rmw_zenoh_cpp/config/DEFAULT_RMW_ZENOH_SESSION_CONFIG.json5 b/rmw_zenoh_cpp/config/DEFAULT_RMW_ZENOH_SESSION_CONFIG.json5
index d04aff2d..eaa570af 100644
--- a/rmw_zenoh_cpp/config/DEFAULT_RMW_ZENOH_SESSION_CONFIG.json5
+++ b/rmw_zenoh_cpp/config/DEFAULT_RMW_ZENOH_SESSION_CONFIG.json5
@@ -462,7 +462,7 @@
       /// A probing procedure for shared memory is performed upon session opening. To enable zenoh to operate
       /// over shared memory (and to not fallback on network mode), shared memory needs to be enabled also on the
       /// subscriber side. By doing so, the probing procedure will succeed and shared memory will operate as expected.
-      enabled: true,
+      enabled: false,
     },
     auth: {
       /// The configuration of authentication.