1use libc::{MSG_PEEK, c_int, c_void, size_t, sockaddr, socklen_t};
2
3#[cfg(not(any(target_os = "espidf", target_os = "nuttx")))]
4use crate::ffi::CStr;
5use crate::io::{self, BorrowedBuf, BorrowedCursor, IoSlice, IoSliceMut};
6use crate::net::{Shutdown, SocketAddr};
7use crate::os::unix::io::{AsFd, AsRawFd, BorrowedFd, FromRawFd, IntoRawFd, RawFd};
8use crate::sys::fd::FileDesc;
9use crate::sys::net::{getsockopt, setsockopt};
10use crate::sys::pal::IsMinusOne;
11use crate::sys_common::{AsInner, FromInner, IntoInner};
12use crate::time::{Duration, Instant};
13use crate::{cmp, mem};
14
15cfg_if::cfg_if! {
16 if #[cfg(target_vendor = "apple")] {
17 use libc::SO_LINGER_SEC as SO_LINGER;
18 } else {
19 use libc::SO_LINGER;
20 }
21}
22
23pub(super) use libc as netc;
24
25use super::{socket_addr_from_c, socket_addr_to_c};
26pub use crate::sys::{cvt, cvt_r};
27
28#[expect(non_camel_case_types)]
29pub type wrlen_t = size_t;
30
31pub struct Socket(FileDesc);
32
33pub fn init() {}
34
35pub fn cvt_gai(err: c_int) -> io::Result<()> {
36 if err == 0 {
37 return Ok(());
38 }
39
40 // We may need to trigger a glibc workaround. See on_resolver_failure() for details.
41 on_resolver_failure();
42
43 #[cfg(not(any(target_os = "espidf", target_os = "nuttx")))]
44 if err == libc::EAI_SYSTEM {
45 return Err(io::Error::last_os_error());
46 }
47
48 #[cfg(not(any(target_os = "espidf", target_os = "nuttx")))]
49 let detail = unsafe {
50 // We can't always expect a UTF-8 environment. When we don't get that luxury,
51 // it's better to give a low-quality error message than none at all.
52 CStr::from_ptr(libc::gai_strerror(err)).to_string_lossy()
53 };
54
55 #[cfg(any(target_os = "espidf", target_os = "nuttx"))]
56 let detail = "";
57
58 Err(io::Error::new(
59 io::ErrorKind::Uncategorized,
60 &format!("failed to lookup address information: {detail}")[..],
61 ))
62}
63
64impl Socket {
65 pub fn new(addr: &SocketAddr, ty: c_int) -> io::Result<Socket> {
66 let fam = match *addr {
67 SocketAddr::V4(..) => libc::AF_INET,
68 SocketAddr::V6(..) => libc::AF_INET6,
69 };
70 Socket::new_raw(fam, ty)
71 }
72
73 pub fn new_raw(fam: c_int, ty: c_int) -> io::Result<Socket> {
74 unsafe {
75 cfg_if::cfg_if! {
76 if #[cfg(any(
77 target_os = "android",
78 target_os = "dragonfly",
79 target_os = "freebsd",
80 target_os = "illumos",
81 target_os = "hurd",
82 target_os = "linux",
83 target_os = "netbsd",
84 target_os = "openbsd",
85 target_os = "cygwin",
86 target_os = "nto",
87 target_os = "solaris",
88 ))] {
89 // On platforms that support it we pass the SOCK_CLOEXEC
90 // flag to atomically create the socket and set it as
91 // CLOEXEC. On Linux this was added in 2.6.27.
92 let fd = cvt(libc::socket(fam, ty | libc::SOCK_CLOEXEC, 0))?;
93 let socket = Socket(FileDesc::from_raw_fd(fd));
94
95 // DragonFlyBSD, FreeBSD and NetBSD use `SO_NOSIGPIPE` as a `setsockopt`
96 // flag to disable `SIGPIPE` emission on socket.
97 #[cfg(any(target_os = "freebsd", target_os = "netbsd", target_os = "dragonfly"))]
98 setsockopt(&socket, libc::SOL_SOCKET, libc::SO_NOSIGPIPE, 1)?;
99
100 Ok(socket)
101 } else {
102 let fd = cvt(libc::socket(fam, ty, 0))?;
103 let fd = FileDesc::from_raw_fd(fd);
104 fd.set_cloexec()?;
105 let socket = Socket(fd);
106
107 // macOS and iOS use `SO_NOSIGPIPE` as a `setsockopt`
108 // flag to disable `SIGPIPE` emission on socket.
109 #[cfg(target_vendor = "apple")]
110 setsockopt(&socket, libc::SOL_SOCKET, libc::SO_NOSIGPIPE, 1)?;
111
112 Ok(socket)
113 }
114 }
115 }
116 }
117
118 #[cfg(not(target_os = "vxworks"))]
119 pub fn new_pair(fam: c_int, ty: c_int) -> io::Result<(Socket, Socket)> {
120 unsafe {
121 let mut fds = [0, 0];
122
123 cfg_if::cfg_if! {
124 if #[cfg(any(
125 target_os = "android",
126 target_os = "dragonfly",
127 target_os = "freebsd",
128 target_os = "illumos",
129 target_os = "linux",
130 target_os = "hurd",
131 target_os = "netbsd",
132 target_os = "openbsd",
133 target_os = "cygwin",
134 target_os = "nto",
135 ))] {
136 // Like above, set cloexec atomically
137 cvt(libc::socketpair(fam, ty | libc::SOCK_CLOEXEC, 0, fds.as_mut_ptr()))?;
138 Ok((Socket(FileDesc::from_raw_fd(fds[0])), Socket(FileDesc::from_raw_fd(fds[1]))))
139 } else {
140 cvt(libc::socketpair(fam, ty, 0, fds.as_mut_ptr()))?;
141 let a = FileDesc::from_raw_fd(fds[0]);
142 let b = FileDesc::from_raw_fd(fds[1]);
143 a.set_cloexec()?;
144 b.set_cloexec()?;
145 Ok((Socket(a), Socket(b)))
146 }
147 }
148 }
149 }
150
151 #[cfg(target_os = "vxworks")]
152 pub fn new_pair(_fam: c_int, _ty: c_int) -> io::Result<(Socket, Socket)> {
153 unimplemented!()
154 }
155
156 pub fn connect(&self, addr: &SocketAddr) -> io::Result<()> {
157 let (addr, len) = socket_addr_to_c(addr);
158 loop {
159 let result = unsafe { libc::connect(self.as_raw_fd(), addr.as_ptr(), len) };
160 if result.is_minus_one() {
161 let err = crate::sys::os::errno();
162 match err {
163 libc::EINTR => continue,
164 libc::EISCONN => return Ok(()),
165 _ => return Err(io::Error::from_raw_os_error(err)),
166 }
167 }
168 return Ok(());
169 }
170 }
171
172 pub fn connect_timeout(&self, addr: &SocketAddr, timeout: Duration) -> io::Result<()> {
173 self.set_nonblocking(true)?;
174 let r = unsafe {
175 let (addr, len) = socket_addr_to_c(addr);
176 cvt(libc::connect(self.as_raw_fd(), addr.as_ptr(), len))
177 };
178 self.set_nonblocking(false)?;
179
180 match r {
181 Ok(_) => return Ok(()),
182 // there's no ErrorKind for EINPROGRESS :(
183 Err(ref e) if e.raw_os_error() == Some(libc::EINPROGRESS) => {}
184 Err(e) => return Err(e),
185 }
186
187 let mut pollfd = libc::pollfd { fd: self.as_raw_fd(), events: libc::POLLOUT, revents: 0 };
188
189 if timeout.as_secs() == 0 && timeout.subsec_nanos() == 0 {
190 return Err(io::Error::ZERO_TIMEOUT);
191 }
192
193 let start = Instant::now();
194
195 loop {
196 let elapsed = start.elapsed();
197 if elapsed >= timeout {
198 return Err(io::const_error!(io::ErrorKind::TimedOut, "connection timed out"));
199 }
200
201 let timeout = timeout - elapsed;
202 let mut timeout = timeout
203 .as_secs()
204 .saturating_mul(1_000)
205 .saturating_add(timeout.subsec_nanos() as u64 / 1_000_000);
206 if timeout == 0 {
207 timeout = 1;
208 }
209
210 let timeout = cmp::min(timeout, c_int::MAX as u64) as c_int;
211
212 match unsafe { libc::poll(&mut pollfd, 1, timeout) } {
213 -1 => {
214 let err = io::Error::last_os_error();
215 if !err.is_interrupted() {
216 return Err(err);
217 }
218 }
219 0 => {}
220 _ => {
221 if cfg!(target_os = "vxworks") {
222 // VxWorks poll does not return POLLHUP or POLLERR in revents. Check if the
223 // connection actually succeeded and return ok only when the socket is
224 // ready and no errors were found.
225 if let Some(e) = self.take_error()? {
226 return Err(e);
227 }
228 } else {
229 // linux returns POLLOUT|POLLERR|POLLHUP for refused connections (!), so look
230 // for POLLHUP or POLLERR rather than read readiness
231 if pollfd.revents & (libc::POLLHUP | libc::POLLERR) != 0 {
232 let e = self.take_error()?.unwrap_or_else(|| {
233 io::const_error!(
234 io::ErrorKind::Uncategorized,
235 "no error set after POLLHUP",
236 )
237 });
238 return Err(e);
239 }
240 }
241
242 return Ok(());
243 }
244 }
245 }
246 }
247
248 pub fn accept(&self, storage: *mut sockaddr, len: *mut socklen_t) -> io::Result<Socket> {
249 // Unfortunately the only known way right now to accept a socket and
250 // atomically set the CLOEXEC flag is to use the `accept4` syscall on
251 // platforms that support it. On Linux, this was added in 2.6.28,
252 // glibc 2.10 and musl 0.9.5.
253 cfg_if::cfg_if! {
254 if #[cfg(any(
255 target_os = "android",
256 target_os = "dragonfly",
257 target_os = "freebsd",
258 target_os = "illumos",
259 target_os = "linux",
260 target_os = "hurd",
261 target_os = "netbsd",
262 target_os = "openbsd",
263 target_os = "cygwin",
264 ))] {
265 unsafe {
266 let fd = cvt_r(|| libc::accept4(self.as_raw_fd(), storage, len, libc::SOCK_CLOEXEC))?;
267 Ok(Socket(FileDesc::from_raw_fd(fd)))
268 }
269 } else {
270 unsafe {
271 let fd = cvt_r(|| libc::accept(self.as_raw_fd(), storage, len))?;
272 let fd = FileDesc::from_raw_fd(fd);
273 fd.set_cloexec()?;
274 Ok(Socket(fd))
275 }
276 }
277 }
278 }
279
280 pub fn duplicate(&self) -> io::Result<Socket> {
281 self.0.duplicate().map(Socket)
282 }
283
284 fn recv_with_flags(&self, mut buf: BorrowedCursor<'_>, flags: c_int) -> io::Result<()> {
285 let ret = cvt(unsafe {
286 libc::recv(
287 self.as_raw_fd(),
288 buf.as_mut().as_mut_ptr() as *mut c_void,
289 buf.capacity(),
290 flags,
291 )
292 })?;
293 unsafe {
294 buf.advance_unchecked(ret as usize);
295 }
296 Ok(())
297 }
298
299 pub fn read(&self, buf: &mut [u8]) -> io::Result<usize> {
300 let mut buf = BorrowedBuf::from(buf);
301 self.recv_with_flags(buf.unfilled(), 0)?;
302 Ok(buf.len())
303 }
304
305 pub fn peek(&self, buf: &mut [u8]) -> io::Result<usize> {
306 let mut buf = BorrowedBuf::from(buf);
307 self.recv_with_flags(buf.unfilled(), MSG_PEEK)?;
308 Ok(buf.len())
309 }
310
311 pub fn read_buf(&self, buf: BorrowedCursor<'_>) -> io::Result<()> {
312 self.recv_with_flags(buf, 0)
313 }
314
315 pub fn read_vectored(&self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
316 self.0.read_vectored(bufs)
317 }
318
319 #[inline]
320 pub fn is_read_vectored(&self) -> bool {
321 self.0.is_read_vectored()
322 }
323
324 fn recv_from_with_flags(
325 &self,
326 buf: &mut [u8],
327 flags: c_int,
328 ) -> io::Result<(usize, SocketAddr)> {
329 // The `recvfrom` function will fill in the storage with the address,
330 // so we don't need to zero it here.
331 // reference: https://linux.die.net/man/2/recvfrom
332 let mut storage: mem::MaybeUninit<libc::sockaddr_storage> = mem::MaybeUninit::uninit();
333 let mut addrlen = size_of_val(&storage) as libc::socklen_t;
334
335 let n = cvt(unsafe {
336 libc::recvfrom(
337 self.as_raw_fd(),
338 buf.as_mut_ptr() as *mut c_void,
339 buf.len(),
340 flags,
341 (&raw mut storage) as *mut _,
342 &mut addrlen,
343 )
344 })?;
345 Ok((n as usize, unsafe { socket_addr_from_c(storage.as_ptr(), addrlen as usize)? }))
346 }
347
348 pub fn recv_from(&self, buf: &mut [u8]) -> io::Result<(usize, SocketAddr)> {
349 self.recv_from_with_flags(buf, 0)
350 }
351
352 #[cfg(any(target_os = "android", target_os = "linux"))]
353 pub fn recv_msg(&self, msg: &mut libc::msghdr) -> io::Result<usize> {
354 let n = cvt(unsafe { libc::recvmsg(self.as_raw_fd(), msg, libc::MSG_CMSG_CLOEXEC) })?;
355 Ok(n as usize)
356 }
357
358 pub fn peek_from(&self, buf: &mut [u8]) -> io::Result<(usize, SocketAddr)> {
359 self.recv_from_with_flags(buf, MSG_PEEK)
360 }
361
362 pub fn write(&self, buf: &[u8]) -> io::Result<usize> {
363 self.0.write(buf)
364 }
365
366 pub fn write_vectored(&self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
367 self.0.write_vectored(bufs)
368 }
369
370 #[inline]
371 pub fn is_write_vectored(&self) -> bool {
372 self.0.is_write_vectored()
373 }
374
375 #[cfg(any(target_os = "android", target_os = "linux"))]
376 pub fn send_msg(&self, msg: &mut libc::msghdr) -> io::Result<usize> {
377 let n = cvt(unsafe { libc::sendmsg(self.as_raw_fd(), msg, 0) })?;
378 Ok(n as usize)
379 }
380
381 pub fn set_timeout(&self, dur: Option<Duration>, kind: libc::c_int) -> io::Result<()> {
382 let timeout = match dur {
383 Some(dur) => {
384 if dur.as_secs() == 0 && dur.subsec_nanos() == 0 {
385 return Err(io::Error::ZERO_TIMEOUT);
386 }
387
388 let secs = if dur.as_secs() > libc::time_t::MAX as u64 {
389 libc::time_t::MAX
390 } else {
391 dur.as_secs() as libc::time_t
392 };
393 let mut timeout = libc::timeval {
394 tv_sec: secs,
395 tv_usec: dur.subsec_micros() as libc::suseconds_t,
396 };
397 if timeout.tv_sec == 0 && timeout.tv_usec == 0 {
398 timeout.tv_usec = 1;
399 }
400 timeout
401 }
402 None => libc::timeval { tv_sec: 0, tv_usec: 0 },
403 };
404 setsockopt(self, libc::SOL_SOCKET, kind, timeout)
405 }
406
407 pub fn timeout(&self, kind: libc::c_int) -> io::Result<Option<Duration>> {
408 let raw: libc::timeval = getsockopt(self, libc::SOL_SOCKET, kind)?;
409 if raw.tv_sec == 0 && raw.tv_usec == 0 {
410 Ok(None)
411 } else {
412 let sec = raw.tv_sec as u64;
413 let nsec = (raw.tv_usec as u32) * 1000;
414 Ok(Some(Duration::new(sec, nsec)))
415 }
416 }
417
418 pub fn shutdown(&self, how: Shutdown) -> io::Result<()> {
419 let how = match how {
420 Shutdown::Write => libc::SHUT_WR,
421 Shutdown::Read => libc::SHUT_RD,
422 Shutdown::Both => libc::SHUT_RDWR,
423 };
424 cvt(unsafe { libc::shutdown(self.as_raw_fd(), how) })?;
425 Ok(())
426 }
427
428 #[cfg(not(target_os = "cygwin"))]
429 pub fn set_linger(&self, linger: Option<Duration>) -> io::Result<()> {
430 let linger = libc::linger {
431 l_onoff: linger.is_some() as libc::c_int,
432 l_linger: linger.unwrap_or_default().as_secs() as libc::c_int,
433 };
434
435 setsockopt(self, libc::SOL_SOCKET, SO_LINGER, linger)
436 }
437
438 #[cfg(target_os = "cygwin")]
439 pub fn set_linger(&self, linger: Option<Duration>) -> io::Result<()> {
440 let linger = libc::linger {
441 l_onoff: linger.is_some() as libc::c_ushort,
442 l_linger: linger.unwrap_or_default().as_secs() as libc::c_ushort,
443 };
444
445 setsockopt(self, libc::SOL_SOCKET, SO_LINGER, linger)
446 }
447
448 pub fn linger(&self) -> io::Result<Option<Duration>> {
449 let val: libc::linger = getsockopt(self, libc::SOL_SOCKET, SO_LINGER)?;
450
451 Ok((val.l_onoff != 0).then(|| Duration::from_secs(val.l_linger as u64)))
452 }
453
454 pub fn set_nodelay(&self, nodelay: bool) -> io::Result<()> {
455 setsockopt(self, libc::IPPROTO_TCP, libc::TCP_NODELAY, nodelay as c_int)
456 }
457
458 pub fn nodelay(&self) -> io::Result<bool> {
459 let raw: c_int = getsockopt(self, libc::IPPROTO_TCP, libc::TCP_NODELAY)?;
460 Ok(raw != 0)
461 }
462
463 #[cfg(any(target_os = "android", target_os = "linux",))]
464 pub fn set_quickack(&self, quickack: bool) -> io::Result<()> {
465 setsockopt(self, libc::IPPROTO_TCP, libc::TCP_QUICKACK, quickack as c_int)
466 }
467
468 #[cfg(any(target_os = "android", target_os = "linux",))]
469 pub fn quickack(&self) -> io::Result<bool> {
470 let raw: c_int = getsockopt(self, libc::IPPROTO_TCP, libc::TCP_QUICKACK)?;
471 Ok(raw != 0)
472 }
473
474 // bionic libc makes no use of this flag
475 #[cfg(target_os = "linux")]
476 pub fn set_deferaccept(&self, accept: u32) -> io::Result<()> {
477 setsockopt(self, libc::IPPROTO_TCP, libc::TCP_DEFER_ACCEPT, accept as c_int)
478 }
479
480 #[cfg(target_os = "linux")]
481 pub fn deferaccept(&self) -> io::Result<u32> {
482 let raw: c_int = getsockopt(self, libc::IPPROTO_TCP, libc::TCP_DEFER_ACCEPT)?;
483 Ok(raw as u32)
484 }
485
486 #[cfg(any(target_os = "freebsd", target_os = "netbsd"))]
487 pub fn set_acceptfilter(&self, name: &CStr) -> io::Result<()> {
488 if !name.to_bytes().is_empty() {
489 const AF_NAME_MAX: usize = 16;
490 let mut buf = [0; AF_NAME_MAX];
491 for (src, dst) in name.to_bytes().iter().zip(&mut buf[..AF_NAME_MAX - 1]) {
492 *dst = *src as libc::c_char;
493 }
494 let mut arg: libc::accept_filter_arg = unsafe { mem::zeroed() };
495 arg.af_name = buf;
496 setsockopt(self, libc::SOL_SOCKET, libc::SO_ACCEPTFILTER, &mut arg)
497 } else {
498 setsockopt(
499 self,
500 libc::SOL_SOCKET,
501 libc::SO_ACCEPTFILTER,
502 core::ptr::null_mut() as *mut c_void,
503 )
504 }
505 }
506
507 #[cfg(any(target_os = "freebsd", target_os = "netbsd"))]
508 pub fn acceptfilter(&self) -> io::Result<&CStr> {
509 let arg: libc::accept_filter_arg =
510 getsockopt(self, libc::SOL_SOCKET, libc::SO_ACCEPTFILTER)?;
511 let s: &[u8] =
512 unsafe { core::slice::from_raw_parts(arg.af_name.as_ptr() as *const u8, 16) };
513 let name = CStr::from_bytes_with_nul(s).unwrap();
514 Ok(name)
515 }
516
517 #[cfg(any(target_os = "android", target_os = "linux",))]
518 pub fn set_passcred(&self, passcred: bool) -> io::Result<()> {
519 setsockopt(self, libc::SOL_SOCKET, libc::SO_PASSCRED, passcred as libc::c_int)
520 }
521
522 #[cfg(any(target_os = "android", target_os = "linux",))]
523 pub fn passcred(&self) -> io::Result<bool> {
524 let passcred: libc::c_int = getsockopt(self, libc::SOL_SOCKET, libc::SO_PASSCRED)?;
525 Ok(passcred != 0)
526 }
527
528 #[cfg(target_os = "netbsd")]
529 pub fn set_local_creds(&self, local_creds: bool) -> io::Result<()> {
530 setsockopt(self, 0 as libc::c_int, libc::LOCAL_CREDS, local_creds as libc::c_int)
531 }
532
533 #[cfg(target_os = "netbsd")]
534 pub fn local_creds(&self) -> io::Result<bool> {
535 let local_creds: libc::c_int = getsockopt(self, 0 as libc::c_int, libc::LOCAL_CREDS)?;
536 Ok(local_creds != 0)
537 }
538
539 #[cfg(target_os = "freebsd")]
540 pub fn set_local_creds_persistent(&self, local_creds_persistent: bool) -> io::Result<()> {
541 setsockopt(
542 self,
543 libc::AF_LOCAL,
544 libc::LOCAL_CREDS_PERSISTENT,
545 local_creds_persistent as libc::c_int,
546 )
547 }
548
549 #[cfg(target_os = "freebsd")]
550 pub fn local_creds_persistent(&self) -> io::Result<bool> {
551 let local_creds_persistent: libc::c_int =
552 getsockopt(self, libc::AF_LOCAL, libc::LOCAL_CREDS_PERSISTENT)?;
553 Ok(local_creds_persistent != 0)
554 }
555
556 #[cfg(not(any(target_os = "solaris", target_os = "illumos", target_os = "vita")))]
557 pub fn set_nonblocking(&self, nonblocking: bool) -> io::Result<()> {
558 let mut nonblocking = nonblocking as libc::c_int;
559 cvt(unsafe { libc::ioctl(self.as_raw_fd(), libc::FIONBIO, &mut nonblocking) }).map(drop)
560 }
561
562 #[cfg(target_os = "vita")]
563 pub fn set_nonblocking(&self, nonblocking: bool) -> io::Result<()> {
564 let option = nonblocking as libc::c_int;
565 setsockopt(self, libc::SOL_SOCKET, libc::SO_NONBLOCK, option)
566 }
567
568 #[cfg(any(target_os = "solaris", target_os = "illumos"))]
569 pub fn set_nonblocking(&self, nonblocking: bool) -> io::Result<()> {
570 // FIONBIO is inadequate for sockets on illumos/Solaris, so use the
571 // fcntl(F_[GS]ETFL)-based method provided by FileDesc instead.
572 self.0.set_nonblocking(nonblocking)
573 }
574
575 #[cfg(any(target_os = "linux", target_os = "freebsd", target_os = "openbsd"))]
576 pub fn set_mark(&self, mark: u32) -> io::Result<()> {
577 #[cfg(target_os = "linux")]
578 let option = libc::SO_MARK;
579 #[cfg(target_os = "freebsd")]
580 let option = libc::SO_USER_COOKIE;
581 #[cfg(target_os = "openbsd")]
582 let option = libc::SO_RTABLE;
583 setsockopt(self, libc::SOL_SOCKET, option, mark as libc::c_int)
584 }
585
586 pub fn take_error(&self) -> io::Result<Option<io::Error>> {
587 let raw: c_int = getsockopt(self, libc::SOL_SOCKET, libc::SO_ERROR)?;
588 if raw == 0 { Ok(None) } else { Ok(Some(io::Error::from_raw_os_error(raw as i32))) }
589 }
590
591 // This is used by sys_common code to abstract over Windows and Unix.
592 pub fn as_raw(&self) -> RawFd {
593 self.as_raw_fd()
594 }
595}
596
597impl AsInner<FileDesc> for Socket {
598 #[inline]
599 fn as_inner(&self) -> &FileDesc {
600 &self.0
601 }
602}
603
604impl IntoInner<FileDesc> for Socket {
605 fn into_inner(self) -> FileDesc {
606 self.0
607 }
608}
609
610impl FromInner<FileDesc> for Socket {
611 fn from_inner(file_desc: FileDesc) -> Self {
612 Self(file_desc)
613 }
614}
615
616impl AsFd for Socket {
617 fn as_fd(&self) -> BorrowedFd<'_> {
618 self.0.as_fd()
619 }
620}
621
622impl AsRawFd for Socket {
623 #[inline]
624 fn as_raw_fd(&self) -> RawFd {
625 self.0.as_raw_fd()
626 }
627}
628
629impl IntoRawFd for Socket {
630 fn into_raw_fd(self) -> RawFd {
631 self.0.into_raw_fd()
632 }
633}
634
635impl FromRawFd for Socket {
636 unsafe fn from_raw_fd(raw_fd: RawFd) -> Self {
637 Self(FromRawFd::from_raw_fd(raw_fd))
638 }
639}
640
641// In versions of glibc prior to 2.26, there's a bug where the DNS resolver
642// will cache the contents of /etc/resolv.conf, so changes to that file on disk
643// can be ignored by a long-running program. That can break DNS lookups on e.g.
644// laptops where the network comes and goes. See
645// https://sourceware.org/bugzilla/show_bug.cgi?id=984. Note however that some
646// distros including Debian have patched glibc to fix this for a long time.
647//
648// A workaround for this bug is to call the res_init libc function, to clear
649// the cached configs. Unfortunately, while we believe glibc's implementation
650// of res_init is thread-safe, we know that other implementations are not
651// (https://github.com/rust-lang/rust/issues/43592). Code here in std could
652// try to synchronize its res_init calls with a Mutex, but that wouldn't
653// protect programs that call into libc in other ways. So instead of calling
654// res_init unconditionally, we call it only when we detect we're linking
655// against glibc version < 2.26. (That is, when we both know its needed and
656// believe it's thread-safe).
657#[cfg(all(target_os = "linux", target_env = "gnu"))]
658fn on_resolver_failure() {
659 use crate::sys;
660
661 // If the version fails to parse, we treat it the same as "not glibc".
662 if let Some(version: (usize, usize)) = sys::os::glibc_version() {
663 if version < (2, 26) {
664 unsafe { libc::res_init() };
665 }
666 }
667}
668
669#[cfg(not(all(target_os = "linux", target_env = "gnu")))]
670fn on_resolver_failure() {}
671