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base: linux: store syslog fd in a OnceCell

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Ensure that openlog_and_get_socket() is only called once by storing its
result in a OnceCell. This fixes logging initialization when the syslog
State structure was constructed more than once, causing the log fd to be
invalidated and breaking sandboxed startup.

BUG=b:242103548
TEST=Start crosvm on Linux with sandbox enabled (default mode)

Change-Id: I663a7e918b81f4c23415a28cfcc2c72f6b4a51d8
Fixes: 7dbdc73063 ("base & src: allow multiple log inits.")
Reviewed-on: https://chromium-review.googlesource.com/c/crosvm/crosvm/+/3842813
Tested-by: Daniel Verkamp <dverkamp@chromium.org>
Reviewed-by: Noah Gold <nkgold@google.com>
Commit-Queue: Daniel Verkamp <dverkamp@chromium.org>
This commit is contained in:
Daniel Verkamp 2022-08-19 17:08:37 -07:00 committed by crosvm LUCI
parent 583a2963d3
commit fd0b2ecdaa
1 changed files with 29 additions and 25 deletions
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54
base/src/sys/unix/linux/syslog.rs
View file

@ -25,6 +25,7 @@ use libc::LOG_NDELAY;
use libc::LOG_PERROR;
use libc::LOG_PID;
use libc::LOG_USER;
use once_cell::sync::OnceCell;
use super::super::getpid;
use crate::syslog::Error;
@ -35,31 +36,35 @@ use crate::RawDescriptor;
const SYSLOG_PATH: &str = "/dev/log";
/// Global syslog socket derived from the fd opened by `openlog()`.
/// This is initialized in `PlatformSyslog::new()`.
static SYSLOG_SOCKET: OnceCell<UnixDatagram> = OnceCell::new();
pub struct PlatformSyslog {}
struct SyslogSocket {
socket: UnixDatagram,
}
struct SyslogSocket {}
impl Write for SyslogSocket {
fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
const SEND_RETRY: usize = 2;
for _ in 0..SEND_RETRY {
match self.socket.send(buf) {
Ok(l) => return Ok(l),
Err(e) => match e.kind() {
ErrorKind::ConnectionRefused
| ErrorKind::ConnectionReset
| ErrorKind::ConnectionAborted
| ErrorKind::NotConnected => {
let res = self.socket.connect(SYSLOG_PATH);
if res.is_err() {
break;
if let Some(socket) = SYSLOG_SOCKET.get() {
for _ in 0..SEND_RETRY {
match socket.send(buf) {
Ok(l) => return Ok(l),
Err(e) => match e.kind() {
ErrorKind::ConnectionRefused
| ErrorKind::ConnectionReset
| ErrorKind::ConnectionAborted
| ErrorKind::NotConnected => {
let res = socket.connect(SYSLOG_PATH);
if res.is_err() {
break;
}
}
}
_ => {}
},
_ => {}
},
}
}
}
// Abandon all hope but this is fine
@ -72,24 +77,23 @@ impl Write for SyslogSocket {
}
impl Syslog for PlatformSyslog {
/// WARNING: calling this function more than once will cause the previous
/// syslogger FD to be closed, invalidating the log::Log object in an unsafe
/// manner. Currently, the callers of this method are extremely careful to
/// call it exactly once.
///
/// b/238923791 is tracking fixing this problem.
fn new(
proc_name: String,
facility: Facility,
) -> Result<(Option<Box<dyn log::Log + Send>>, Option<RawDescriptor>), Error> {
let socket = openlog_and_get_socket()?;
// Calling openlog_and_get_socket() more than once will cause the previous syslogger FD to
// be closed, invalidating the log::Log object in an unsafe manner. The OnceCell
// get_or_try_init() ensures we only call it once.
//
// b/238923791 is tracking fixing this problem.
let socket = SYSLOG_SOCKET.get_or_try_init(openlog_and_get_socket)?;
let mut builder = env_logger::Builder::new();
// Everything is filtered layer above
builder.filter_level(log::LevelFilter::Trace);
let fd = socket.as_raw_fd();
builder.target(env_logger::Target::Pipe(Box::new(SyslogSocket { socket })));
builder.target(env_logger::Target::Pipe(Box::new(SyslogSocket {})));
builder.format(move |buf, record| {
const MONTHS: [&str; 12] = [
"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec",