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9pfs: root device #7

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9pfs: root device #7

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d5cad5e
treewide: group import statements std, external, crate
KarlK90 Jan 30, 2025
ed59bf5
treewide: refactor mkdir and read_file
KarlK90 Jan 30, 2025
592fac3
9pfs: wip
KarlK90 Jan 31, 2025
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57 changes: 29 additions & 28 deletions src/usbg_9pfs.rs
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Original file line number Diff line number Diff line change
@@ -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;

Expand All @@ -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();
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@michaelolbrich michaelolbrich Feb 1, 2025

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This looks wrong. In the else case, the string is converted multiple times.


mount_apivfs("/sys/kernel/config", "configfs")?;

Expand All @@ -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}");
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@michaelolbrich michaelolbrich Feb 1, 2025

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I think @a3f said, that this name does not really matter, so maybe just use a fixed name.
@a3f, what do you think?

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@a3f a3f Feb 11, 2025

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I was mistaken. If I change this to something different from the first argument of the mount call, mounting fails.

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)?;
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@michaelolbrich michaelolbrich Feb 1, 2025

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Hmm, the file name read above is not necessarily UTF-8, so converting it into a String is technically not correct.


thread::sleep(Duration::from_secs(1));

options.root = Some(udc);

let d = time::Duration::new(1, 0);
thread::sleep(d);
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@michaelolbrich michaelolbrich Feb 1, 2025

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Unrelated, this should be a separate commit.

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)
}
Expand Down