krata/xenstore/src/client.rs

use crate::bus::{XsdBusError, XsdSocket};
use crate::sys::{
    XSD_DIRECTORY, XSD_GET_DOMAIN_PATH, XSD_INTRODUCE, XSD_MKDIR, XSD_READ, XSD_RM, XSD_SET_PERMS,
    XSD_TRANSACTION_END, XSD_TRANSACTION_START, XSD_WRITE,
};
use log::trace;
use std::ffi::CString;

pub const XS_PERM_NONE: u32 = 0x00;
pub const XS_PERM_READ: u32 = 0x01;
pub const XS_PERM_WRITE: u32 = 0x02;
pub const XS_PERM_READ_WRITE: u32 = XS_PERM_READ | XS_PERM_WRITE;

pub struct XsdClient {
    pub socket: XsdSocket,
}

#[derive(Debug, Copy, Clone)]
pub struct XsPermission {
    pub id: u32,
    pub perms: u32,
}

impl XsPermission {
    pub fn encode(&self) -> Result<String, XsdBusError> {
        let c = match self.perms {
            XS_PERM_READ_WRITE => 'b',
            XS_PERM_WRITE => 'w',
            XS_PERM_READ => 'r',
            XS_PERM_NONE => 'n',
            _ => return Err(XsdBusError::new("invalid permissions")),
        };
        Ok(format!("{}{}", c, self.id))
    }
}

pub trait XsdInterface {
    fn list(&mut self, path: &str) -> Result<Vec<String>, XsdBusError>;
    fn read(&mut self, path: &str) -> Result<Vec<u8>, XsdBusError>;
    fn read_string(&mut self, path: &str) -> Result<String, XsdBusError>;
    fn write(&mut self, path: &str, data: Vec<u8>) -> Result<bool, XsdBusError>;
    fn write_string(&mut self, path: &str, data: &str) -> Result<bool, XsdBusError>;
    fn mkdir(&mut self, path: &str) -> Result<bool, XsdBusError>;
    fn rm(&mut self, path: &str) -> Result<bool, XsdBusError>;
    fn set_perms(&mut self, path: &str, perms: &[XsPermission]) -> Result<bool, XsdBusError>;

    fn mknod(&mut self, path: &str, perms: &[XsPermission]) -> Result<bool, XsdBusError> {
        let result1 = self.write_string(path, "")?;
        let result2 = self.set_perms(path, perms)?;
        Ok(result1 && result2)
    }

    fn read_string_optional(&mut self, path: &str) -> Result<Option<String>, XsdBusError> {
        Ok(match self.read_string(path) {
            Ok(value) => Some(value),
            Err(error) => {
                if error.to_string() == "ENOENT" {
                    None
                } else {
                    return Err(error);
                }
            }
        })
    }

    fn list_any(&mut self, path: &str) -> Result<Vec<String>, XsdBusError> {
        Ok(match self.list(path) {
            Ok(value) => value,
            Err(error) => {
                if error.to_string() == "ENOENT" {
                    Vec::new()
                } else {
                    return Err(error);
                }
            }
        })
    }
}

impl XsdClient {
    pub fn open() -> Result<XsdClient, XsdBusError> {
        let socket = XsdSocket::dial()?;
        Ok(XsdClient { socket })
    }

    fn list(&mut self, tx: u32, path: &str) -> Result<Vec<String>, XsdBusError> {
        trace!("list tx={tx} path={path}");
        let response = self.socket.send_single(tx, XSD_DIRECTORY, path)?;
        response.parse_string_vec()
    }

    fn read(&mut self, tx: u32, path: &str) -> Result<Vec<u8>, XsdBusError> {
        trace!("read tx={tx} path={path}");
        let response = self.socket.send_single(tx, XSD_READ, path)?;
        Ok(response.payload)
    }

    fn write(&mut self, tx: u32, path: &str, data: Vec<u8>) -> Result<bool, XsdBusError> {
        trace!("write tx={tx} path={path} data={:?}", data);
        let mut buffer = Vec::new();
        let path = CString::new(path)?;
        buffer.extend_from_slice(path.as_bytes_with_nul());
        buffer.extend_from_slice(data.as_slice());
        let response = self.socket.send(tx, XSD_WRITE, buffer.as_slice())?;
        response.parse_bool()
    }

    fn mkdir(&mut self, tx: u32, path: &str) -> Result<bool, XsdBusError> {
        trace!("mkdir tx={tx} path={path}");
        self.socket.send_single(tx, XSD_MKDIR, path)?.parse_bool()
    }

    fn rm(&mut self, tx: u32, path: &str) -> Result<bool, XsdBusError> {
        trace!("rm tx={tx} path={path}");
        let result = self.socket.send_single(tx, XSD_RM, path);
        if let Err(error) = result {
            if error.to_string() == "ENOENT" {
                return Ok(true);
            }
            return Err(error);
        }
        result.unwrap().parse_bool()
    }

    fn set_perms(
        &mut self,
        tx: u32,
        path: &str,
        perms: &[XsPermission],
    ) -> Result<bool, XsdBusError> {
        trace!("set_perms tx={tx} path={path} perms={:?}", perms);
        let mut items: Vec<String> = Vec::new();
        items.push(path.to_string());
        for perm in perms {
            items.push(perm.encode()?);
        }
        let items_str: Vec<&str> = items.iter().map(|x| x.as_str()).collect();
        let response = self.socket.send_multiple(tx, XSD_SET_PERMS, &items_str)?;
        response.parse_bool()
    }

    pub fn transaction(&mut self) -> Result<XsdTransaction, XsdBusError> {
        trace!("transaction start");
        let response = self.socket.send_single(0, XSD_TRANSACTION_START, "")?;
        let str = response.parse_string()?;
        let tx = str.parse::<u32>()?;
        Ok(XsdTransaction { client: self, tx })
    }

    pub fn get_domain_path(&mut self, domid: u32) -> Result<String, XsdBusError> {
        let response =
            self.socket
                .send_single(0, XSD_GET_DOMAIN_PATH, domid.to_string().as_str())?;
        response.parse_string()
    }

    pub fn introduce_domain(
        &mut self,
        domid: u32,
        mfn: u64,
        evtchn: u32,
    ) -> Result<bool, XsdBusError> {
        trace!("introduce domain domid={domid} mfn={mfn} evtchn={evtchn}");
        let response = self.socket.send_multiple(
            0,
            XSD_INTRODUCE,
            &[
                domid.to_string().as_str(),
                mfn.to_string().as_str(),
                evtchn.to_string().as_str(),
            ],
        )?;
        response.parse_bool()
    }
}

pub struct XsdTransaction<'a> {
    client: &'a mut XsdClient,
    tx: u32,
}

impl XsdInterface for XsdClient {
    fn list(&mut self, path: &str) -> Result<Vec<String>, XsdBusError> {
        self.list(0, path)
    }

    fn read(&mut self, path: &str) -> Result<Vec<u8>, XsdBusError> {
        self.read(0, path)
    }

    fn read_string(&mut self, path: &str) -> Result<String, XsdBusError> {
        Ok(String::from_utf8(self.read(0, path)?)?)
    }

    fn write(&mut self, path: &str, data: Vec<u8>) -> Result<bool, XsdBusError> {
        self.write(0, path, data)
    }

    fn write_string(&mut self, path: &str, data: &str) -> Result<bool, XsdBusError> {
        self.write(0, path, data.as_bytes().to_vec())
    }

    fn mkdir(&mut self, path: &str) -> Result<bool, XsdBusError> {
        self.mkdir(0, path)
    }

    fn rm(&mut self, path: &str) -> Result<bool, XsdBusError> {
        self.rm(0, path)
    }

    fn set_perms(&mut self, path: &str, perms: &[XsPermission]) -> Result<bool, XsdBusError> {
        self.set_perms(0, path, perms)
    }
}

impl XsdInterface for XsdTransaction<'_> {
    fn list(&mut self, path: &str) -> Result<Vec<String>, XsdBusError> {
        self.client.list(self.tx, path)
    }

    fn read(&mut self, path: &str) -> Result<Vec<u8>, XsdBusError> {
        self.client.read(self.tx, path)
    }

    fn read_string(&mut self, path: &str) -> Result<String, XsdBusError> {
        Ok(String::from_utf8(self.client.read(self.tx, path)?)?)
    }

    fn write(&mut self, path: &str, data: Vec<u8>) -> Result<bool, XsdBusError> {
        self.client.write(self.tx, path, data)
    }

    fn write_string(&mut self, path: &str, data: &str) -> Result<bool, XsdBusError> {
        self.client.write(self.tx, path, data.as_bytes().to_vec())
    }

    fn mkdir(&mut self, path: &str) -> Result<bool, XsdBusError> {
        self.client.mkdir(self.tx, path)
    }

    fn rm(&mut self, path: &str) -> Result<bool, XsdBusError> {
        self.client.rm(self.tx, path)
    }

    fn set_perms(&mut self, path: &str, perms: &[XsPermission]) -> Result<bool, XsdBusError> {
        self.client.set_perms(self.tx, path, perms)
    }
}

impl XsdTransaction<'_> {
    pub fn end(&mut self, abort: bool) -> Result<bool, XsdBusError> {
        let abort_str = if abort { "F" } else { "T" };

        trace!("transaction end abort={}", abort);
        self.client
            .socket
            .send_single(self.tx, XSD_TRANSACTION_END, abort_str)?
            .parse_bool()
    }

    pub fn commit(&mut self) -> Result<bool, XsdBusError> {
        self.end(false)
    }

    pub fn abort(&mut self) -> Result<bool, XsdBusError> {
        self.end(true)
    }
}