feat(skills): WASM host 函数真实实现 — zclaw_log/http_fetch/file_read (Phase 4B)

替换 stub 为真实实现:
- zclaw_log: 读取 guest 内存并 log
- zclaw_http_fetch: ureq v3 同步 GET (10s timeout, network_allowed 守卫)
- zclaw_file_read: 沙箱 /workspace 目录读取 (路径校验防逃逸)
添加 ureq v3 workspace 依赖, 25 测试全通过。

Cargo.lock

@@ -5492,6 +5492,7 @@ version = "0.23.37"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "758025cb5fccfd3bc2fd74708fd4682be41d99e5dff73c377c0646c6012c73a4"
 dependencies = [
+ "log",
  "once_cell",
  "ring",
  "rustls-pki-types",
@@ -7858,6 +7859,35 @@ version = "0.9.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8ecb6da28b8a351d773b68d5825ac39017e680750f980f3a1a85cd8dd28a47c1"
 
+[[package]]
+name = "ureq"
+version = "3.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dea7109cdcd5864d4eeb1b58a1648dc9bf520360d7af16ec26d0a9354bafcfc0"
+dependencies = [
+ "base64 0.22.1",
+ "flate2",
+ "log",
+ "percent-encoding",
+ "rustls",
+ "rustls-pki-types",
+ "ureq-proto",
+ "utf8-zero",
+ "webpki-roots",
+]
+
+[[package]]
+name = "ureq-proto"
+version = "0.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e994ba84b0bd1b1b0cf92878b7ef898a5c1760108fe7b6010327e274917a808c"
+dependencies = [
+ "base64 0.22.1",
+ "http 1.4.0",
+ "httparse",
+ "log",
+]
+
 [[package]]
 name = "url"
 version = "2.5.8"
@@ -7895,6 +7925,12 @@ version = "0.7.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "09cc8ee72d2a9becf2f2febe0205bbed8fc6615b7cb429ad062dc7b7ddd036a9"
 
+[[package]]
+name = "utf8-zero"
+version = "0.8.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b8c0a043c9540bae7c578c88f91dda8bd82e59ae27c21baca69c8b191aaf5a6e"
+
 [[package]]
 name = "utf8_iter"
 version = "1.0.4"
@@ -9723,7 +9759,6 @@ dependencies = [
  "tracing",
  "uuid",
  "zclaw-hands",
- "zclaw-kernel",
  "zclaw-runtime",
  "zclaw-skills",
  "zclaw-types",
@@ -9840,6 +9875,7 @@ dependencies = [
  "thiserror 2.0.18",
  "tokio",
  "tracing",
+ "ureq",
  "uuid",
  "wasmtime",
  "wasmtime-wasi",

Cargo.toml

@@ -63,6 +63,9 @@ libsqlite3-sys = { version = "0.27", features = ["bundled"] }
 # HTTP client (for LLM drivers)
 reqwest = { version = "0.12", default-features = false, features = ["json", "stream", "rustls-tls"] }
 
+# Synchronous HTTP (for WASM host functions in blocking threads)
+ureq = { version = "3", features = ["rustls"] }
+
 # URL parsing
 url = "2"
 

crates/zclaw-skills/Cargo.toml

@@ -9,7 +9,7 @@ description = "ZCLAW skill system"
 
 [features]
 default = []
-wasm = ["wasmtime", "wasmtime-wasi/p1"]
+wasm = ["wasmtime", "wasmtime-wasi/p1", "ureq"]
 
 [dependencies]
 zclaw-types = { workspace = true }
@@ -27,3 +27,4 @@ shlex = { workspace = true }
 # Optional WASM runtime (enable with --features wasm)
 wasmtime = { workspace = true, optional = true }
 wasmtime-wasi = { workspace = true, optional = true }
+ureq = { workspace = true, optional = true }

crates/zclaw-skills/src/wasm_runner.rs

@@ -230,49 +230,100 @@ fn create_engine_config() -> Config {
 }
 
 /// Add ZCLAW host functions to the wasmtime linker.
-fn add_host_functions(linker: &mut Linker<WasiP1Ctx>, _network_allowed: bool) -> Result<()> {
+fn add_host_functions(linker: &mut Linker<WasiP1Ctx>, network_allowed: bool) -> Result<()> {
     linker
         .func_wrap(
             "env",
             "zclaw_log",
-            |_caller: Caller<'_, WasiP1Ctx>, _ptr: u32, _len: u32| {
+            |mut caller: Caller<'_, WasiP1Ctx>, ptr: u32, len: u32| {
-                debug!("[WasmSkill] guest called zclaw_log");
+                let msg = read_guest_string(&mut caller, ptr, len);
+                debug!("[WasmSkill] guest log: {}", msg);
             },
         )
         .map_err(|e| {
             zclaw_types::ZclawError::ToolError(format!("Failed to add zclaw_log: {}", e))
         })?;
 
+    // zclaw_http_fetch(url_ptr, url_len, out_ptr, out_cap) -> bytes_written (-1 = error)
+    // Performs a synchronous GET request. Result is written to guest memory as JSON string.
+    let net = network_allowed;
     linker
         .func_wrap(
             "env",
             "zclaw_http_fetch",
-            |_caller: Caller<'_, WasiP1Ctx>,
+            move |mut caller: Caller<'_, WasiP1Ctx>,
-             _url_ptr: u32,
+                  url_ptr: u32,
-             _url_len: u32,
+                  url_len: u32,
-             _out_ptr: u32,
+                  out_ptr: u32,
-             _out_cap: u32|
+                  out_cap: u32|
                   -> i32 {
-                warn!("[WasmSkill] guest called zclaw_http_fetch — denied");
+                if !net {
+                    warn!("[WasmSkill] guest called zclaw_http_fetch — denied (network not allowed)");
+                    return -1;
+                }
+
+                let url = read_guest_string(&mut caller, url_ptr, url_len);
+                if url.is_empty() {
+                    return -1;
+                }
+
+                debug!("[WasmSkill] guest http_fetch: {}", url);
+
+                // Synchronous HTTP GET (we're already on a blocking thread)
+                let agent = ureq::Agent::config_builder()
+                    .timeout_global(Some(std::time::Duration::from_secs(10)))
+                    .build()
+                    .new_agent();
+                let response = agent.get(&url).call();
+
+                match response {
+                    Ok(mut resp) => {
+                        let body = resp.body_mut().read_to_string().unwrap_or_default();
+                        write_guest_bytes(&mut caller, out_ptr, out_cap, body.as_bytes())
+                    }
+                    Err(e) => {
+                        warn!("[WasmSkill] http_fetch error for {}: {}", url, e);
                         -1
+                    }
+                }
             },
         )
         .map_err(|e| {
             zclaw_types::ZclawError::ToolError(format!("Failed to add zclaw_http_fetch: {}", e))
         })?;
 
+    // zclaw_file_read(path_ptr, path_len, out_ptr, out_cap) -> bytes_written (-1 = error)
+    // Reads a file from the preopened /workspace directory. Paths must be relative.
     linker
         .func_wrap(
             "env",
             "zclaw_file_read",
-            |_caller: Caller<'_, WasiP1Ctx>,
+            |mut caller: Caller<'_, WasiP1Ctx>,
-             _path_ptr: u32,
+             path_ptr: u32,
-             _path_len: u32,
+             path_len: u32,
-             _out_ptr: u32,
+             out_ptr: u32,
-             _out_cap: u32|
+             out_cap: u32|
              -> i32 {
-                warn!("[WasmSkill] guest called zclaw_file_read — denied");
+                let path = read_guest_string(&mut caller, path_ptr, path_len);
+                if path.is_empty() {
+                    return -1;
+                }
+
+                // Security: only allow reads under /workspace (preopen root)
+                if path.starts_with("..") || path.starts_with('/') {
+                    warn!("[WasmSkill] guest file_read denied — path escapes sandbox: {}", path);
+                    return -1;
+                }
+
+                let full_path = format!("/workspace/{}", path);
+
+                match std::fs::read(&full_path) {
+                    Ok(data) => write_guest_bytes(&mut caller, out_ptr, out_cap, &data),
+                    Err(e) => {
+                        debug!("[WasmSkill] file_read error for {}: {}", path, e);
                         -1
+                    }
+                }
             },
         )
         .map_err(|e| {
@@ -282,6 +333,38 @@ fn add_host_functions(linker: &mut Linker<WasiP1Ctx>, _network_allowed: bool) ->
     Ok(())
 }
 
+/// Read a string from WASM guest memory.
+fn read_guest_string(caller: &mut Caller<'_, WasiP1Ctx>, ptr: u32, len: u32) -> String {
+    let mem = match caller.get_export("memory") {
+        Some(Extern::Memory(m)) => m,
+        _ => return String::new(),
+    };
+    let offset = ptr as usize;
+    let length = len as usize;
+    let data = mem.data(&caller);
+    if offset + length > data.len() {
+        return String::new();
+    }
+    String::from_utf8_lossy(&data[offset..offset + length]).into_owned()
+}
+
+/// Write bytes to WASM guest memory. Returns the number of bytes written, or -1 on overflow.
+fn write_guest_bytes(caller: &mut Caller<'_, WasiP1Ctx>, ptr: u32, cap: u32, data: &[u8]) -> i32 {
+    let mem = match caller.get_export("memory") {
+        Some(Extern::Memory(m)) => m,
+        _ => return -1,
+    };
+    let offset = ptr as usize;
+    let capacity = cap as usize;
+    let write_len = data.len().min(capacity);
+    if offset + write_len > mem.data_size(&caller) {
+        return -1;
+    }
+    // Safety: we've bounds-checked the write region.
+    mem.data_mut(&mut *caller)[offset..offset + write_len].copy_from_slice(&data[..write_len]);
+    write_len as i32
+}
+
 
 #[cfg(test)]
 mod tests {