add shm example using fs shm

examples/shm_test/CMakeLists.txt

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+# ##############################################################################
+# apps/examples/shm_test/CMakeLists.txt
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more contributor
+# license agreements.  See the NOTICE file distributed with this work for
+# additional information regarding copyright ownership.  The ASF licenses this
+# file to you 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.
+#
+# ##############################################################################
+
+if(CONFIG_EXAMPLES_SHM)
+  nuttx_add_application(
+    NAME
+    ${CONFIG_EXAMPLES_SHM_PROGNAME}
+    SRCS
+    shm_main.c
+    STACKSIZE
+    ${CONFIG_EXAMPLES_SHM_STACKSIZE}
+    PRIORITY
+    ${CONFIG_EXAMPLES_SHM_PRIORITY})
+endif()

examples/shm_test/Kconfig

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+#
+# For a description of the syntax of this configuration file,
+# see the file kconfig-language.txt in the NuttX tools repository.
+#
+
+config EXAMPLES_SHM
+	tristate "SHM example"
+	default n
+	depends on FS_SHMFS
+	---help---
+		Enable the SHM example which has an shm producer and consumer
+
+if EXAMPLES_SHM
+
+config EXAMPLES_SHM_PROGNAME
+	string "Program name"
+	default "shm_test"
+	---help---
+		This is the name of the program that will be used when the NSH ELF
+		program is installed.
+
+config EXAMPLES_SHM_PRIORITY
+	int "SHM task priority"
+	default 100
+
+config EXAMPLES_SHM_STACKSIZE
+	int "SHM stack size"
+	default DEFAULT_TASK_STACKSIZE
+
+endif

examples/shm_test/Make.defs

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+############################################################################
+# apps/examples/shm_test/Make.defs
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.  The
+# ASF licenses this file to you 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.
+#
+############################################################################
+
+ifneq ($(CONFIG_EXAMPLES_SHM),)
+CONFIGURED_APPS += $(APPDIR)/examples/shm_test
+endif

examples/shm_test/Makefile

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+############################################################################
+# apps/examples/shm_test/Makefile
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.  The
+# ASF licenses this file to you 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 $(APPDIR)/Make.defs
+
+# SHM test built-in application info
+
+PROGNAME  = $(CONFIG_EXAMPLES_SHM_PROGNAME)
+PRIORITY  = $(CONFIG_EXAMPLES_SHM_PRIORITY)
+STACKSIZE = $(CONFIG_EXAMPLES_SHM_STACKSIZE)
+MODULE    = $(CONFIG_EXAMPLES_SHM)
+
+# SHM test Example
+
+MAINSRC = shm_main.c
+
+# Build with WebAssembly when CONFIG_INTERPRETERS_WAMR is enabled
+
+WASM_BUILD = both
+
+# Mode of WebAssembly Micro Runtime
+
+WAMR_MODE  = AOT
+
+include $(APPDIR)/Application.mk

examples/shm_test/shm_main.c

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+/****************************************************************************
+ * apps/examples/shm_test/shm_main.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you 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.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <fcntl.h>
+#include <nuttx/config.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/shm.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+void shm_producer(const int shm_size, const char *shm_name)
+{
+  /* Write Hello World! to shared memory */
+
+  const char *message_0 = "Hello";
+  const char *message_1 = "World!";
+
+  /* Shared memory file descriptor */
+
+  int shm_fd;
+
+  /* Pointer to shared memory object */
+
+  void *ptr;
+
+  /* Create the shared memory object */
+
+  shm_fd = shm_open(shm_name, O_CREAT | O_RDWR, 0666);
+
+  /* Configure the size of the shared memory object */
+
+  ftruncate(shm_fd, shm_size);
+
+  /* Memory map the shared memory object */
+
+  ptr = mmap(0, shm_size, PROT_WRITE, MAP_SHARED, shm_fd, 0);
+
+  /* Write to the shared memory object */
+
+  sprintf(ptr, "%s", message_0);
+
+  ptr += strlen(message_0);
+  sprintf(ptr, "%s", message_1);
+  ptr += strlen(message_1);
+
+  printf("Producer Wrote to SHM: %s%s\n", message_0, message_1);
+}
+
+void shm_consumer(const int shm_size, const char *shm_name)
+{
+  /* Shared memory file descriptor */
+
+  int shm_fd;
+
+  /* Pointer to shared memory object */
+
+  void *ptr;
+
+  /* Open the shared memory object */
+
+  shm_fd = shm_open(shm_name, O_RDONLY, 0666);
+
+  /* Memory map the shared memory object */
+
+  ptr = mmap(0, shm_size, PROT_READ, MAP_SHARED, shm_fd, 0);
+
+  /* Read from the shared memory object */
+
+  printf("Consumer Read from SHM: %s\n", (char *)ptr);
+
+  /* Remove the shared memory object */
+
+  shm_unlink(shm_name);
+}
+
+/****************************************************************************
+ * shm_main
+ ****************************************************************************/
+
+int main(int argc, FAR char *argv[])
+{
+  const int shm_size = 2048;
+  const char *shm_name = "OS";
+
+  shm_producer(shm_size, shm_name);
+  shm_consumer(shm_size, shm_name);
+  return 0;
+}