syslog_rs/sync/

syslog_sync_internal.rs

/*-
 * syslog-rs - a syslog client translated from libc to rust
 * 
 * Copyright 2025 Aleksandr Morozov
 * 
 * The syslog-rs crate can be redistributed and/or modified
 * under the terms of either of the following licenses:
 *
 *   1. the Mozilla Public License Version 2.0 (the “MPL”) OR
 *                     
 *   2. EUROPEAN UNION PUBLIC LICENCE v. 1.2 EUPL © the European Union 2007, 2016
 */


use std::borrow::Cow;
use std::marker::PhantomData;
use std::thread::sleep;
use std::time::Duration;

use nix::libc;


use crate::formatters::SyslogFormatter;
use crate::map_error_os;
use crate::portable;
use crate::common::*;
use crate::error::{SyRes/* , SyslogError*/};
use crate::socket::TapType;
use crate::SyslogDestination;

use super::socket::*;

/// A common instance which describes the syslog state
#[derive(Debug)]
pub struct SyncSyslogInternal<F: SyslogFormatter, D: SyslogDestination>
{   
    /// An identification i.e program name, thread name
    logtag: String, 

    /// A pid of the program.
    logpid: String,

    /// Defines how syslog operates
    logstat: LogStat,

    /// Holds the facility 
    facility: LogFacility,

    /// A logmask
    logmask: i32,

    /// A stream (unixdatagram, udp, tcp)
    stream: D::SocketTap,

    _p: PhantomData<F>,
}


impl<F: SyslogFormatter, D: SyslogDestination> Drop for SyncSyslogInternal<F, D> 
{
    fn drop(&mut self) 
    {
        // call disconnect log to sync all data
        let _ = self.disconnectlog();
    }
}

/// Private realization. It is assumed that functions which are called,
/// are called after 'lock' is locked.
impl<F: SyslogFormatter, D: SyslogDestination> SyncSyslogInternal<F, D>
{
    /// Creates new instance of [SyncSyslogInternal] which contains all 
    /// client syslog logic.
    ///
    /// # Arguments
    ///
    /// * `ident` - An optional argument which takes ref to str. If none, the
    ///     ident will be set later. Yje ident will be trucated to 48 UTF8
    ///     chars.
    /// 
    /// * `logstat` - A [LogStat] flags separated by '|'
    /// 
    /// * `facility` - A [LogFacility] flag
    /// 
    /// * `req_tap` - A type of the syslog instance reuired. See [TapTypeData].
    /// 
    /// # Returns
    ///
    /// A [SyRes] is returned with following:
    /// 
    /// * [Result::Ok] - with the instance.
    /// 
    /// * [Result::Err] - with error description.
    pub(crate) 
    fn new(
        ident: Option<&str>, 
        logstat: LogStat, 
        facility: LogFacility, 
        req_tap: D
    ) -> SyRes<Self>
    {
        // check if log_facility is invalid
        let log_facility =
            if facility.is_empty() == false && 
                (facility & !LogMask::LOG_FACMASK).is_empty() == true
            {
                facility
            }
            else
            {
                // default facility code
                LogFacility::LOG_USER
            };

        let logtag = 
            match ident
            {
                Some(r) => 
                    truncate_n(r, RFC_MAX_APP_NAME).to_string(),
                None => 
                    truncate_n(
                        portable::p_getprogname()
                            .unwrap_or("".to_string())
                            .as_str(),
                        RFC_MAX_APP_NAME
                    )
                    .to_string()
            };

        let sock = D::SocketTap::new(req_tap)?;
            
        return Ok(
            Self
            {
                logtag: logtag,
                logpid: portable::get_pid().to_string(),
                logstat: logstat, 
                facility: log_facility,
                logmask: 0xff,
                stream: sock,
                _p: PhantomData
            }
        );
    }

    /// Tap data should be the same type.
    pub(crate) 
    fn update_tap_data(&mut self, tap_data: D) -> SyRes<()>
    {
        let is_con = self.stream.is_connected();

        if is_con == true
        {
            self
                .stream
                .disconnectlog()
                .map_err(|e|
                    map_error_os!(e, "update_tap_data() can not disconnect log properly")
                )?;
        }

        self.stream.update_tap_data(tap_data);

        if is_con == true
        {
            // replace with new instance
            self.stream.connectlog()?;
        }

        return Ok(());
    }

    #[inline]
    pub(super)
    fn send_to_stderr(&self, msg: &[Cow<'_, str>])
    {
        if self.logstat.intersects(LogStat::LOG_PERROR) == true
        {
            let stderr_lock = std::io::stderr().lock();
            let newline = "\n";

            let _ = send_to_fd(stderr_lock, msg, &newline);
        }
    }

    #[inline]
    fn send_to_syscons(&self, msg_payload: &[Cow<'_, str>])
    {
        use std::fs::File;
        use std::os::unix::fs::OpenOptionsExt;

        if self.logstat.intersects(LogStat::LOG_CONS)
        {
            let syscons = 
                File
                    ::options()
                        .create(false)
                        .read(false)
                        .write(true)
                        .custom_flags(libc::O_NONBLOCK | libc::O_CLOEXEC)
                        .open(*PATH_CONSOLE);

            if let Ok(file) = syscons
            {
                let newline = "\n";
                let _ = send_to_fd(file, msg_payload, newline);
            }
        }
    }

    #[inline]
    fn is_logmasked(&self, pri: i32) -> bool
    {
        return ((1 << (pri & LogMask::LOG_PRIMASK)) & self.logmask) == 0;
    }

    /// Returns the type of the socket.
    #[inline]
    pub(crate)
    fn get_taptype(&self) -> TapType
    {
        return self.stream.get_type();
    }

    /// Returns the maximum msg size in bytes. (Full msg with headers.)
    #[inline]
    pub(crate) 
    fn get_max_msg_size(&self) -> usize
    {
        return self.stream.get_max_msg_size();
    }

    pub(crate) 
    fn set_logmask(&mut self, logmask: i32) -> i32
    {
        let oldmask = self.logmask;

        if logmask != 0
        {
            self.logmask = logmask;
        }

        return oldmask;
    }

    #[inline]
    pub(crate) 
    fn set_logtag<L: AsRef<str>>(&mut self, logtag: L, update_pid: bool)
    {
        self.logtag = 
            truncate_n(logtag.as_ref(), RFC_MAX_APP_NAME).to_string();

        if update_pid == true
        {
            self.logpid = portable::get_pid().to_string();
        }

        return;
    }

    /// Disconnects the unix stream from syslog.
    #[inline]
    pub(crate) 
    fn disconnectlog(&mut self) -> SyRes<()>
    {
        return 
            self
                .stream
                .disconnectlog()
                .map_err(|e| map_error_os!(e, "can not disconnect log properly"));
    }

    /// Connects unix stream to the syslog and sets up the properties of
    /// the unix stream.
    #[inline]
    pub(crate) 
    fn connectlog(&mut self) -> SyRes<()>
    {
        return self.stream.connectlog();
    }

    

    /// An internal function which is called by the syslog or vsyslog.
    /// A glibc implementation RFC3164
    pub(crate) 
    fn vsyslog1(&mut self, mut pri: Priority, fmt: &F)
    {
        // check for invalid bits
        if let Err(e) = pri.check_invalid_bits()
        {
            self.send_to_stderr(&[Cow::Owned(e.to_string())]);
        }

        // check priority against setlogmask
        if self.is_logmasked(pri.bits()) == true
        {
            return;
        }

        // set default facility if not specified in pri
        if (pri.bits() & LOG_FACMASK) == 0
        {
            pri.set_facility(self.facility);
        }

        let progname = self.logtag.clone();
        let pid = self.logpid.clone();

        // format msg
        let msg_formatted = 
            F::vsyslog1_format(self.get_taptype(), self.get_max_msg_size(), pri, &progname, &pid, fmt);
        
        // output to stderr if required
        self.send_to_stderr(msg_formatted.get_stderr_output());
        
        if self.stream.is_connected() == false
        {
            // open connection
            match self.connectlog()
            {
                Ok(_) => {},
                Err(e) =>
                {
                    self.send_to_stderr(&[Cow::Owned(e.into_inner())]);
                    return;
                }
            }
        }

        let fullmsg = msg_formatted.concat();

        // There are two possible scenarios when send may fail:
        // 1. syslog temporary unavailable
        // 2. syslog out of buffer space
        // If we are connected to priv socket then in case of 1 we reopen connection
        //      and retry once.
        // If we are connected to unpriv then in case of 2 repeatedly retrying to send
        //      until syslog socket buffer space will be cleared

        loop
        {
            match self.stream.send(fullmsg.as_bytes())
            {
                Ok(_) => 
                    return,
                Err(err) =>
                {  
                    if self.get_taptype().is_network() == false
                    { 
                        if let Some(libc::ENOBUFS) = err.raw_os_error()
                        {
                            // scenario 2
                            if self.get_taptype().is_priv() == true
                            {
                                break;
                            }

                            sleep(Duration::from_micros(1));
                        }
                        else
                        {
                            // scenario 1

                            let _ = self.disconnectlog();
                            match self.connectlog()
                            {
                                Ok(_) => {},
                                Err(_e) => break,
                            }

                            // if resend will fail then probably the scn 2 will take place
                        }   
                    }
                    else
                    {
                        let _ = self.disconnectlog();
                        match self.connectlog()
                        {
                            Ok(_) => {},
                            Err(e) => 
                            {
                                self.send_to_stderr(&[Cow::Owned(e.to_string())]);

                                break;
                            },
                        }
                    }
                }
            }
        } // loop


        // If program reached this point then transmission over socket failed.
        // Try to output message to console

        let _ = self.send_to_syscons(msg_formatted.get_stderr_output());

        return;
    }
}


#[cfg(test)]
mod tests
{
    use super::*;

    #[cfg(target_os = "linux")]
    #[test]
    fn test_log_cons()
    {
        use crate::{formatters::FormatRfc3146, SyslogLocal};

        let net_tap = SyslogLocal::new();
        
        //let net_tap = TapTypeData::new_unix(None, true).unwrap();

        // needs root priv
        let correct = 
            SyncSyslogInternal::<FormatRfc3146, _>::new(Some("test1"), LogStat::LOG_PID | LogStat::LOG_CONS, LogFacility::LOG_DAEMON, net_tap)
                .unwrap();
        
        let msg = &[Cow::Borrowed("header msg message payload")];

        
        correct.send_to_syscons(msg);

        return;
    }

    #[cfg(any(
        target_os = "freebsd",
        target_os = "dragonfly",
        target_os = "openbsd",
        target_os = "netbsd",
        target_os = "macos"
    ))]
    #[test]
    fn test_log_cons()
    {
        use crate::{formatters::FormatRfc5424, SyslogLocal};

        let net_tap = SyslogLocal::new();
        //let net_tap = TapTypeData::new_unix(None, true).unwrap();

        // needs root priv
        let correct = 
            SyncSyslogInternal::<FormatRfc5424, _>::new(Some("test1"), LogStat::LOG_PID | LogStat::LOG_CONS, LogFacility::LOG_DAEMON, net_tap)
                .unwrap();
        
        correct.send_to_syscons(&[Cow::Borrowed("header msg"), Cow::Borrowed("message payload")]);
    }

    #[cfg(target_os = "linux")]
    #[test]
    fn test_bit_operations()
    {
        use crate::{formatters::FormatRfc3146, SyslogLocal};

        let net_tap = SyslogLocal::new();
        //let net_tap = TapTypeData::new_unix(None, true).unwrap();

        let correct = 
            SyncSyslogInternal::<FormatRfc3146, _>::new(Some("test1"), LogStat::LOG_PID, LogFacility::LOG_DAEMON, net_tap)
                .unwrap();

        assert_eq!(correct.facility, LogFacility::LOG_DAEMON);
        assert_eq!((correct.facility & !LogFacility::LOG_DAEMON), LogFacility::empty());
    }

	#[cfg(any(
        target_os = "freebsd",
        target_os = "dragonfly",
        target_os = "openbsd",
        target_os = "netbsd",
        target_os = "macos"
    ))]
    #[test]
    fn test_bit_operations()
    {
        use crate::{formatters::FormatRfc5424, SyslogLocal};

        let net_tap = SyslogLocal::new();
        //let net_tap = TapTypeData::new_unix(None, true).unwrap();

        let correct = 
            SyncSyslogInternal::<FormatRfc5424, _>::new(Some("test1"), LogStat::LOG_PID, LogFacility::LOG_DAEMON, net_tap)
                .unwrap();

        assert_eq!(correct.facility, LogFacility::LOG_DAEMON);
        assert_eq!((correct.facility & !LogFacility::LOG_DAEMON), LogFacility::empty());
    }

    #[cfg(target_os = "linux")]
    #[test]
    fn test_bit_operations2()
    {
        use crate::{formatters::FormatRfc3146, SyslogLocal};

        let net_tap = SyslogLocal::new();
        //let net_tap = TapTypeData::new_unix(None, true).unwrap();

        let _correct = 
            SyncSyslogInternal::<FormatRfc3146, _>::new(Some("test2"), LogStat::LOG_PID, LogFacility::LOG_DAEMON, net_tap)
                .unwrap();

        let mut pri = Priority::LOG_ALERT;

        let res = pri.check_invalid_bits();

        assert_eq!(res.is_ok(), true);
        assert_eq!(pri.bits(), Priority::LOG_ALERT.bits());
    }

	#[cfg(any(
        target_os = "freebsd",
        target_os = "dragonfly",
        target_os = "openbsd",
        target_os = "netbsd",
        target_os = "macos"
    ))]
	#[test]
    fn test_bit_operations2()
    {
        use crate::{formatters::FormatRfc5424, SyslogLocal};

        let net_tap = SyslogLocal::new();
        //let net_tap = TapTypeData::new_unix(None, true).unwrap();

        let _correct = 
            SyncSyslogInternal::<FormatRfc5424, _>::new(Some("test2"), LogStat::LOG_PID, LogFacility::LOG_DAEMON, net_tap)
                .unwrap();

        let mut pri = Priority::LOG_ALERT;

        let res = pri.check_invalid_bits();

        assert_eq!(res.is_ok(), true);
        assert_eq!(pri.bits(), Priority::LOG_ALERT.bits());
    }

    #[cfg(target_os = "linux")]
    #[test]
    fn test_set_priority()
    {
        use crate::{ formatters::FormatRfc3146, SyslogLocal, LOG_MASK};

        let net_tap = SyslogLocal::new();
        //let net_tap = TapTypeData::new_unix(None, true).unwrap();

        let mut correct = 
            SyncSyslogInternal::<FormatRfc3146, _>::new(Some("test1"), LogStat::LOG_PID, LogFacility::LOG_DAEMON, net_tap)
                .unwrap();

        let ret = correct.set_logmask(LOG_MASK!(Priority::LOG_ERR));

        assert_eq!(ret, 0xff);

        let ret = correct.set_logmask(LOG_MASK!(Priority::LOG_ERR));

        assert_eq!(ret, LOG_MASK!(Priority::LOG_ERR));

        let ret = correct.is_logmasked(Priority::LOG_WARNING.bits());
        assert_eq!(ret, true);

        let ret = correct.is_logmasked(Priority::LOG_ERR.bits());
        assert_eq!(ret, false);

        let ret = correct.is_logmasked(Priority::LOG_CRIT.bits());
        assert_eq!(ret, true);
    }

	#[cfg(any(
		    target_os = "freebsd",
		    target_os = "dragonfly",
		    target_os = "openbsd",
		    target_os = "netbsd",
		    target_os = "macos"
		))]
	#[test]
    fn test_set_priority()
    {
        use crate::{ formatters::FormatRfc5424, SyslogLocal, LOG_MASK};

        let net_tap = SyslogLocal::new();
        //let net_tap = TapTypeData::new_unix(None, true).unwrap();

        let mut correct = 
            SyncSyslogInternal::<FormatRfc5424, _>::new(Some("test1"), LogStat::LOG_PID, LogFacility::LOG_DAEMON, net_tap)
                .unwrap();

        let ret = correct.set_logmask(LOG_MASK!(Priority::LOG_ERR));

        assert_eq!(ret, 0xff);

        let ret = correct.set_logmask(LOG_MASK!(Priority::LOG_ERR));

        assert_eq!(ret, LOG_MASK!(Priority::LOG_ERR));

        let ret = correct.is_logmasked(Priority::LOG_WARNING.bits());
        assert_eq!(ret, true);

        let ret = correct.is_logmasked(Priority::LOG_ERR.bits());
        assert_eq!(ret, false);

        let ret = correct.is_logmasked(Priority::LOG_CRIT.bits());
        assert_eq!(ret, true);
    }

    #[cfg(target_os = "linux")]
    #[test]
    fn test_set_priority2()
    {
        use crate::{ formatters::FormatRfc3146, SyslogLocal, LOG_MASK};
        
        let net_tap = SyslogLocal::new();
        //let net_tap = TapTypeData::new_unix(None, true).unwrap();

        let mut correct = 
            SyncSyslogInternal::<FormatRfc3146, _>::new(Some("test1"), LogStat::LOG_PID, LogFacility::LOG_DAEMON, net_tap)
                .unwrap();

        let ret = correct.set_logmask(!LOG_MASK!(Priority::LOG_ERR));

        assert_eq!(ret, 0xff);

        let ret = correct.is_logmasked(Priority::LOG_WARNING.bits());
        assert_eq!(ret, false);

        let ret = correct.is_logmasked(Priority::LOG_ERR.bits());
        assert_eq!(ret, true);

        let ret = correct.is_logmasked(Priority::LOG_CRIT.bits());
        assert_eq!(ret, false);
    }

	#[cfg(any(
		target_os = "freebsd",
		target_os = "dragonfly",
		target_os = "openbsd",
		target_os = "netbsd",
		target_os = "macos"
	))]
	#[test]
    fn test_set_priority2()
    {
        use crate::{ formatters::FormatRfc5424, SyslogLocal, LOG_MASK};
        
        let net_tap = SyslogLocal::new();
        //let net_tap = TapTypeData::new_unix(None, true).unwrap();

        let mut correct = 
            SyncSyslogInternal::<FormatRfc5424, _>::new(Some("test1"), LogStat::LOG_PID, LogFacility::LOG_DAEMON, net_tap)
                .unwrap();

        let ret = correct.set_logmask(!LOG_MASK!(Priority::LOG_ERR));

        assert_eq!(ret, 0xff);

        let ret = correct.is_logmasked(Priority::LOG_WARNING.bits());
        assert_eq!(ret, false);

        let ret = correct.is_logmasked(Priority::LOG_ERR.bits());
        assert_eq!(ret, true);

        let ret = correct.is_logmasked(Priority::LOG_CRIT.bits());
        assert_eq!(ret, false);
    }
}