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