9pfs: wip

Author: KarlK90

src/usbg_9pfs.rs

@@ -1,9 +1,9 @@
 // SPDX-License-Identifier: GPL-2.0-only
 
 use std::fs::read_dir;
-use std::os::unix::ffi::OsStrExt;
 use std::os::unix::fs::symlink;
-use std::{thread, time};
+use std::thread;
+use std::time::Duration;
 
 use log::debug;
 
@@ -12,15 +12,24 @@ use crate::mount::mount_apivfs;
 use crate::util::{mkdir, write_file};
 use crate::Result;
 
-fn setup_9pfs_gadget(device: &String) -> Result<()> {
+fn setup_9pfs_gadget(options: &mut CmdlineOptions) -> Result<()> {
     debug!("Initializing USB 9pfs gadget ...");
 
-    let udc = read_dir("/sys/class/udc")
-        .map_err(|e| format!("Failed to list /sys/class/udc: {e}"))?
-        .next()
-        .ok_or("No UDC found to attach the 9pfs gadget".to_string())?
-        .map_err(|e| format!("Failed to inspect the first entry in /sys/class/udc: {e}"))?
-        .file_name();
+    let udc = if let Some(device) = &options.root {
+        device.to_owned()
+    } else {
+        read_dir("/sys/class/udc")
+            .map_err(|e| format!("Failed to list /sys/class/udc: {e}"))?
+            .next()
+            .ok_or("No UDC found to attach the 9pfs gadget".to_string())?
+            .map_err(|e| format!("Failed to inspect the first entry in /sys/class/udc: {e}"))?
+            .file_name()
+            .into_string()
+            .map_err(|e| format!("invalid utf-8 in file name: {e:?}"))?
+    }
+    .as_bytes()
+    .escape_ascii()
+    .to_string();
 
     mount_apivfs("/sys/kernel/config", "configfs")?;
 
@@ -46,38 +55,30 @@ fn setup_9pfs_gadget(device: &String) -> Result<()> {
     mkdir("/sys/kernel/config/usb_gadget/9pfs/configs/c.1")?;
     mkdir("/sys/kernel/config/usb_gadget/9pfs/configs/c.1/strings/0x409")?;
 
-    let function = format!("/sys/kernel/config/usb_gadget/9pfs/functions/usb9pfs.{device}");
-    let link = format!("/sys/kernel/config/usb_gadget/9pfs/configs/c.1/usb9pfs.{device}");
+    let function = format!("/sys/kernel/config/usb_gadget/9pfs/functions/usb9pfs.{udc}");
+    let link = format!("/sys/kernel/config/usb_gadget/9pfs/configs/c.1/usb9pfs.{udc}");
     mkdir(&function)?;
     symlink(&function, &link)?;
 
-    debug!(
-        "Attaching 9pfs gatget to UDC {}",
-        udc.as_bytes().escape_ascii()
-    );
-    write_file(
-        "/sys/kernel/config/usb_gadget/9pfs/UDC",
-        udc.as_encoded_bytes(),
-    )?;
+    debug!("Attaching 9pfs gatget to UDC {udc}",);
+    write_file("/sys/kernel/config/usb_gadget/9pfs/UDC", &udc)?;
+
+    thread::sleep(Duration::from_secs(1));
+
+    options.root = Some(udc);
 
-    let d = time::Duration::new(1, 0);
-    thread::sleep(d);
     Ok(())
 }
 
-pub fn prepare_9pfs_gadget(options: &CmdlineOptions) -> Result<bool> {
+pub fn prepare_9pfs_gadget(options: &mut CmdlineOptions) -> Result<bool> {
     if options.rootfstype.as_deref() == Some("9p")
         && options
             .rootflags
             .as_deref()
             .is_some_and(|flags| flags.contains("trans=usbg"))
     {
-        if let Some(root) = &options.root {
-            setup_9pfs_gadget(root)?;
-            Ok(true)
-        } else {
-            Err("Missing root= for 9p!".into())
-        }
+        setup_9pfs_gadget(options)?;
+        Ok(true)
     } else {
         Ok(false)
     }