examples/leds_rust: Add Rust App for blinking the LED

examples/leds_rust/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_LEDS_RUST
+	tristate "\"LEDs Rust\" example"
+	default n
+	depends on USERLED
+	---help---
+		Enable the \"LEDs Rust\" example
+
+if EXAMPLES_LEDS_RUST
+
+config EXAMPLES_LEDS_RUST_PROGNAME
+	string "Program name"
+	default "leds_rust"
+	---help---
+		This is the name of the program that will be used when the
+		program is installed.
+
+config EXAMPLES_LEDS_RUST_PRIORITY
+	int "LEDs Rust task priority"
+	default 100
+
+config EXAMPLES_LEDS_RUST_STACKSIZE
+	int "LEDs Rust stack size"
+	default DEFAULT_TASK_STACKSIZE
+
+endif

examples/leds_rust/Make.defs

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+############################################################################
+# apps/examples/leds_rust/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_LEDS_RUST),)
+CONFIGURED_APPS += $(APPDIR)/examples/leds_rust
+endif

examples/leds_rust/Makefile

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+############################################################################
+# apps/examples/leds_rust/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
+
+# Hello, Rust! built-in application info
+
+PROGNAME  = $(CONFIG_EXAMPLES_LEDS_RUST_PROGNAME)
+PRIORITY  = $(CONFIG_EXAMPLES_LEDS_RUST_PRIORITY)
+STACKSIZE = $(CONFIG_EXAMPLES_LEDS_RUST_STACKSIZE)
+MODULE    = $(CONFIG_EXAMPLES_LEDS_RUST)
+
+# Hello, Rust! Example
+
+MAINSRC = leds_rust_main.rs
+
+RUSTFLAGS += -C panic=abort -O
+
+include $(APPDIR)/Application.mk

examples/leds_rust/leds_rust_main.rs

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+/****************************************************************************
+ * apps/examples/leds_rust/leds_rust_main.rs
+ *
+ * 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.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Attributes
+ ****************************************************************************/
+
+/* Comment out these lines for testing with Rust Standard Library */
+
+#![no_main]
+#![no_std]
+
+/****************************************************************************
+ * Uses
+ ****************************************************************************/
+
+#[cfg(target_os = "none")]
+use core::{
+    panic::PanicInfo,
+    result::Result::{self, Err, Ok},
+};
+
+/****************************************************************************
+ * Modules
+ ****************************************************************************/
+
+mod nuttx;
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Panic Handler (needed for [no_std] compilation)
+ ****************************************************************************/
+
+#[cfg(target_os = "none")] /* For NuttX */
+#[panic_handler]
+fn panic(_panic: &PanicInfo<'_>) -> ! {
+    loop {}
+}
+
+/****************************************************************************
+ * rust_main
+ ****************************************************************************/
+
+fn rust_main(_argc: i32, _argv: *const *const u8) -> Result<i32, i32> {
+    /* "Hello, Rust!!" using puts() from libc */
+
+    nuttx::safe_puts("Hello, Rust!!");
+
+    /* Blink LED 1 using ioctl() from NuttX */
+
+    nuttx::safe_puts("Opening /dev/userleds");
+    let fd = nuttx::safe_open("/dev/userleds", nuttx::O_WRONLY)?;
+    nuttx::safe_puts("Set LED 1 to 1");
+
+    nuttx::safe_ioctl(fd, nuttx::ULEDIOC_SETALL, 1)?;
+    nuttx::safe_puts("Sleeping...");
+    unsafe {
+        nuttx::usleep(500_000);
+    }
+
+    nuttx::safe_puts("Set LED 1 to 0");
+    nuttx::safe_ioctl(fd, nuttx::ULEDIOC_SETALL, 0)?;
+    unsafe {
+        nuttx::close(fd);
+    }
+
+    /* Exit with status 0 */
+
+    Ok(0)
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * leds_rust_main
+ ****************************************************************************/
+
+#[no_mangle]
+pub extern "C" fn leds_rust_main(_argc: i32, _argv: *const *const u8) -> i32 {
+    /* Call the program logic in Rust Main */
+
+    let res = rust_main(0, core::ptr::null());
+
+    /* If Rust Main returns an error, print it */
+
+    if let Err(e) = res {
+        unsafe {
+            nuttx::printf(
+                b"ERROR: rust_main() failed with error %d\n\0" as *const u8,
+                e,
+            );
+        }
+        e
+    } else {
+        0
+    }
+}
+
+/****************************************************************************
+ * main
+ ****************************************************************************/
+
+#[cfg(not(target_os = "none"))] /* For Testing Locally */
+fn main() {
+    leds_rust_main(0, core::ptr::null());
+}

examples/leds_rust/nuttx.rs

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+/****************************************************************************
+ * apps/examples/leds_rust/nuttx.rs
+ *
+ * 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.
+ *
+ ****************************************************************************/
+
+/* NuttX Definitions for Rust Apps */
+
+/****************************************************************************
+ * Uses
+ ****************************************************************************/
+
+use core::result::Result::{self, Err, Ok};
+
+/****************************************************************************
+ * Externs
+ ****************************************************************************/
+
+extern "C" {
+    pub fn printf(format: *const u8, ...) -> i32;
+    pub fn open(path: *const u8, oflag: i32, ...) -> i32;
+    pub fn close(fd: i32) -> i32;
+    pub fn ioctl(fd: i32, request: i32, ...) -> i32;
+    pub fn usleep(usec: u32) -> u32;
+    pub fn puts(s: *const u8) -> i32;
+}
+
+/****************************************************************************
+ * Public Constants
+ ****************************************************************************/
+
+pub const ENAMETOOLONG: i32 = 36;
+pub const O_WRONLY: i32 = 1 << 1;
+pub const PATH_MAX: usize = 256;
+pub const PUTS_MAX: usize = 256;
+pub const ULEDIOC_SETALL: i32 = 0x1d03;
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/* Copy the Rust Str to the Byte Buffer and terminate with null */
+
+fn copy_to_buffer(s: &str, buffer: &mut [u8]) -> Result<(), ()> {
+    let byte_str = s.as_bytes();
+    let len = byte_str.len();
+    if len >= buffer.len() {
+        Err(())
+    } else {
+        buffer[..len].copy_from_slice(&byte_str[..len]);
+        buffer[len] = 0;
+        Ok(())
+    }
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/* Safe Version of open() */
+
+pub fn safe_open(path: &str, oflag: i32) -> Result<i32, i32> {
+    let mut buffer = [0u8; PATH_MAX];
+    let res = copy_to_buffer(path, &mut buffer);
+    if res.is_err() {
+        unsafe {
+            puts(b"ERROR: safe_open() path size exceeds PATH_MAX\0" as *const u8);
+        }
+        return Err(-ENAMETOOLONG);
+    }
+
+    let fd = unsafe { open(buffer.as_ptr(), oflag) };
+    if fd < 0 {
+        Err(fd)
+    } else {
+        Ok(fd)
+    }
+}
+
+/* Safe Version of ioctl() */
+
+pub fn safe_ioctl(fd: i32, request: i32, arg: i32) -> Result<i32, i32> {
+    let ret = unsafe { ioctl(fd, request, arg) };
+    if ret < 0 {
+        Err(ret)
+    } else {
+        Ok(ret)
+    }
+}
+
+/* Safe Version of puts() */
+
+pub fn safe_puts(s: &str) {
+    let mut buffer = [0u8; PUTS_MAX];
+    let res = copy_to_buffer(s, &mut buffer);
+    if res.is_err() {
+        unsafe {
+            puts(b"ERROR: safe_puts() string size exceeds PUTS_MAX\0" as *const u8);
+        }
+    } else {
+        unsafe {
+            puts(buffer.as_ptr());
+        }
+    }
+}