新增环境变量设置和获取功能，优化命令执行逻辑

Author: ZR233

uboot-shell/examples/env_var.rs

@@ -0,0 +1,61 @@
+use std::{
+    net::TcpStream,
+    process::{Child, Command},
+    time::Duration,
+};
+
+use log::info;
+use uboot_shell::UbootShell;
+
+fn main() {
+    env_logger::init();
+
+    let (mut out, mut uboot) = new_uboot();
+
+    uboot.set_env("fdt_addr", "0x40000000").unwrap();
+    info!("set fdt_addr ok");
+    assert_eq!(uboot.env_int("fdt_addr").unwrap(), 0x40000000);
+
+    info!("finish");
+    let _ = out.kill();
+    let _ = out.wait();
+}
+
+fn new_uboot() -> (Child, UbootShell) {
+    // qemu-system-aarch64 -machine virt -cpu cortex-a57 -nographic -bios assets/u-boot.bin -serial tcp::12345,server
+    let out = Command::new("qemu-system-aarch64")
+        .args([
+            "-machine",
+            "virt",
+            "-cpu",
+            "cortex-a57",
+            "-nographic",
+            "-serial",
+            "tcp::12345,server",
+            "-bios",
+            "assets/u-boot.bin",
+        ])
+        .spawn()
+        .unwrap();
+
+    let tx;
+
+    loop {
+        std::thread::sleep(Duration::from_millis(100));
+        match TcpStream::connect("127.0.0.1:12345") {
+            Ok(s) => {
+                tx = s;
+                break;
+            }
+            Err(e) => {
+                println!("wait for qemu serial port ready: {e}");
+            }
+        }
+    }
+
+    let rx = tx.try_clone().unwrap();
+    rx.set_read_timeout(Some(Duration::from_millis(300)))
+        .unwrap();
+    println!("connect ok");
+    (out, UbootShell::new(tx, rx).unwrap())
+}

uboot-shell/src/lib.rs

@@ -169,17 +169,24 @@ impl UbootShell {
 
     pub fn cmd_without_reply(&mut self, cmd: &str) -> Result<()> {
         self.tx().write_all(cmd.as_bytes())?;
-        self.tx().write_all("\r\n".as_bytes())?;
+        self.tx().write_all("\n".as_bytes())?;
         self.tx().flush()?;
-        self.wait_for_reply(cmd)?;
-        debug!("cmd ok");
+        // self.wait_for_reply(cmd)?;
+        // debug!("cmd ok");
         Ok(())
     }
 
     pub fn cmd(&mut self, cmd: &str) -> Result<String> {
+        info!("cmd: {cmd}");
         self.cmd_without_reply(cmd)?;
         let perfix = self.perfix.clone();
-        self.wait_for_reply(&perfix)
+        let res = self
+            .wait_for_reply(&perfix)?
+            .trim_end()
+            .trim_end_matches(self.perfix.as_str().trim())
+            .trim_end()
+            .to_string();
+        Ok(res)
     }
 
     pub fn set_env(&mut self, name: impl Into<String>, value: impl Into<String>) -> Result<()> {
@@ -190,18 +197,25 @@ impl UbootShell {
     pub fn env(&mut self, name: impl Into<String>) -> Result<String> {
         let name = name.into();
         let s = self.cmd(&format!("echo ${}", name))?;
-        if s.is_empty() {
-            return Err(Error::new(
+        let sp = s
+            .split("\n")
+            .filter(|s| !s.trim().is_empty())
+            .collect::<Vec<_>>();
+        let s = sp
+            .last()
+            .ok_or(Error::new(
                 ErrorKind::NotFound,
                 format!("env {} not found", name),
-            ));
-        }
+            ))?
+            .to_string();
         Ok(s)
     }
 
     pub fn env_int(&mut self, name: impl Into<String>) -> Result<usize> {
         let name = name.into();
         let line = self.env(&name)?;
+        debug!("env {name} = {line}");
+
         parse_int(&line).ok_or(Error::new(
             ErrorKind::InvalidData,
             format!("env {name} is not a number"),