From c27a42ee690e6ad2dabf3094bf92f70baa00ada0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E7=8E=8B=E5=AE=87=E9=80=B8?= <Strawberry_Str@hotmail.com>
Date: Tue, 31 Dec 2024 00:23:06 +0900
Subject: [PATCH 01/14] feat: add cygwin support

---
 src/errno.rs        | 346 +++++++++++++++++++++++++++++++++++++++++++-
 src/fcntl.rs        |   5 +-
 src/sys/resource.rs |   6 +-
 src/unistd.rs       |   2 +
 4 files changed, 348 insertions(+), 11 deletions(-)

diff --git a/src/errno.rs b/src/errno.rs
index 2dae6154b7..0d9d2d0fa0 100644
--- a/src/errno.rs
+++ b/src/errno.rs
@@ -24,7 +24,8 @@ cfg_if! {
         unsafe fn errno_location() -> *mut c_int {
             unsafe { libc::__error() }
         }
-    } else if #[cfg(any(target_os = "android", netbsdlike))] {
+    } else if #[cfg(any(target_os = "android", netbsdlike, target_os = "cygwin"))] {
+        #[cfg_attr(target_os = "cygwin", no_mangle)]
         unsafe fn errno_location() -> *mut c_int {
             unsafe { libc::__errno() }
         }
@@ -280,6 +281,7 @@ fn desc(errno: Errno) -> &'static str {
             target_os = "aix",
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         ECHRNG => "Channel number out of range",
 
@@ -289,6 +291,7 @@ fn desc(errno: Errno) -> &'static str {
             target_os = "aix",
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         EL2NSYNC => "Level 2 not synchronized",
 
@@ -298,6 +301,7 @@ fn desc(errno: Errno) -> &'static str {
             target_os = "aix",
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         EL3HLT => "Level 3 halted",
 
@@ -307,6 +311,7 @@ fn desc(errno: Errno) -> &'static str {
             target_os = "aix",
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         EL3RST => "Level 3 reset",
 
@@ -316,6 +321,7 @@ fn desc(errno: Errno) -> &'static str {
             target_os = "aix",
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         ELNRNG => "Link number out of range",
 
@@ -325,6 +331,7 @@ fn desc(errno: Errno) -> &'static str {
             target_os = "aix",
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         EUNATCH => "Protocol driver not attached",
 
@@ -334,6 +341,7 @@ fn desc(errno: Errno) -> &'static str {
             target_os = "aix",
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         ENOCSI => "No CSI structure available",
 
@@ -343,6 +351,7 @@ fn desc(errno: Errno) -> &'static str {
             target_os = "aix",
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         EL2HLT => "Level 2 halted",
 
@@ -351,6 +360,7 @@ fn desc(errno: Errno) -> &'static str {
             solarish,
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         EBADE => "Invalid exchange",
 
@@ -359,6 +369,7 @@ fn desc(errno: Errno) -> &'static str {
             solarish,
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         EBADR => "Invalid request descriptor",
 
@@ -367,6 +378,7 @@ fn desc(errno: Errno) -> &'static str {
             solarish,
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         EXFULL => "Exchange full",
 
@@ -375,6 +387,7 @@ fn desc(errno: Errno) -> &'static str {
             solarish,
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         ENOANO => "No anode",
 
@@ -383,6 +396,7 @@ fn desc(errno: Errno) -> &'static str {
             solarish,
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         EBADRQC => "Invalid request code",
 
@@ -391,6 +405,7 @@ fn desc(errno: Errno) -> &'static str {
             solarish,
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         EBADSLT => "Invalid slot",
 
@@ -399,6 +414,7 @@ fn desc(errno: Errno) -> &'static str {
             solarish,
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         EBFONT => "Bad font file format",
 
@@ -408,6 +424,7 @@ fn desc(errno: Errno) -> &'static str {
             target_os = "fuchsia",
             target_os = "hurd",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         ENOSTR => "Device not a stream",
 
@@ -417,6 +434,7 @@ fn desc(errno: Errno) -> &'static str {
             target_os = "fuchsia",
             target_os = "hurd",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         ENODATA => "No data available",
 
@@ -426,6 +444,7 @@ fn desc(errno: Errno) -> &'static str {
             target_os = "fuchsia",
             target_os = "hurd",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         ETIME => "Timer expired",
 
@@ -435,6 +454,7 @@ fn desc(errno: Errno) -> &'static str {
             target_os = "fuchsia",
             target_os = "hurd",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         ENOSR => "Out of streams resources",
 
@@ -443,6 +463,7 @@ fn desc(errno: Errno) -> &'static str {
             solarish,
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         ENONET => "Machine is not on the network",
 
@@ -451,6 +472,7 @@ fn desc(errno: Errno) -> &'static str {
             solarish,
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         ENOPKG => "Package not installed",
 
@@ -460,6 +482,7 @@ fn desc(errno: Errno) -> &'static str {
             target_os = "fuchsia",
             target_os = "hurd",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         EREMOTE => "Object is remote",
 
@@ -477,6 +500,7 @@ fn desc(errno: Errno) -> &'static str {
             solarish,
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         EADV => "Advertise error",
 
@@ -485,6 +509,7 @@ fn desc(errno: Errno) -> &'static str {
             solarish,
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         ESRMNT => "Srmount error",
 
@@ -493,6 +518,7 @@ fn desc(errno: Errno) -> &'static str {
             solarish,
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         ECOMM => "Communication error on send",
 
@@ -502,6 +528,7 @@ fn desc(errno: Errno) -> &'static str {
             target_os = "aix",
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         EPROTO => "Protocol error",
 
@@ -518,6 +545,7 @@ fn desc(errno: Errno) -> &'static str {
             linux_android,
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         EDOTDOT => "RFS specific error",
 
@@ -526,6 +554,7 @@ fn desc(errno: Errno) -> &'static str {
             target_os = "aix",
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         EBADMSG => "Not a data message",
 
@@ -539,6 +568,7 @@ fn desc(errno: Errno) -> &'static str {
             target_os = "haiku",
             target_os = "hurd",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         EOVERFLOW => "Value too large for defined data type",
 
@@ -547,6 +577,7 @@ fn desc(errno: Errno) -> &'static str {
             solarish,
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         ENOTUNIQ => "Name not unique on network",
 
@@ -555,6 +586,7 @@ fn desc(errno: Errno) -> &'static str {
             solarish,
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         EBADFD => "File descriptor in bad state",
 
@@ -563,6 +595,7 @@ fn desc(errno: Errno) -> &'static str {
             solarish,
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         EREMCHG => "Remote address changed",
 
@@ -571,6 +604,7 @@ fn desc(errno: Errno) -> &'static str {
             solarish,
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         ELIBACC => "Can not access a needed shared library",
 
@@ -579,6 +613,7 @@ fn desc(errno: Errno) -> &'static str {
             solarish,
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         ELIBBAD => "Accessing a corrupted shared library",
 
@@ -587,6 +622,7 @@ fn desc(errno: Errno) -> &'static str {
             solarish,
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         ELIBSCN => ".lib section in a.out corrupted",
 
@@ -595,6 +631,7 @@ fn desc(errno: Errno) -> &'static str {
             solarish,
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         ELIBMAX => "Attempting to link in too many shared libraries",
 
@@ -604,6 +641,7 @@ fn desc(errno: Errno) -> &'static str {
             target_os = "fuchsia",
             target_os = "hurd",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         ELIBEXEC => "Cannot exec a shared library directly",
 
@@ -614,6 +652,7 @@ fn desc(errno: Errno) -> &'static str {
             target_os = "fuchsia",
             target_os = "openbsd",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         EILSEQ => "Illegal byte sequence",
 
@@ -631,6 +670,7 @@ fn desc(errno: Errno) -> &'static str {
             solarish,
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         ESTRPIPE => "Streams pipe error",
 
@@ -639,6 +679,7 @@ fn desc(errno: Errno) -> &'static str {
             solarish,
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         EUSERS => "Too many users",
 
@@ -648,6 +689,7 @@ fn desc(errno: Errno) -> &'static str {
             target_os = "netbsd",
             target_os = "redox",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         EOPNOTSUPP => "Operation not supported on transport endpoint",
 
@@ -656,6 +698,7 @@ fn desc(errno: Errno) -> &'static str {
             target_os = "fuchsia",
             target_os = "hurd",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         ESTALE => "Stale file handle",
 
@@ -698,6 +741,7 @@ fn desc(errno: Errno) -> &'static str {
             linux_android,
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         EDQUOT => "Quota exceeded",
 
@@ -707,6 +751,7 @@ fn desc(errno: Errno) -> &'static str {
             target_os = "openbsd",
             target_os = "dragonfly",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         ENOMEDIUM => "No medium found",
 
@@ -724,6 +769,7 @@ fn desc(errno: Errno) -> &'static str {
             target_os = "fuchsia",
             target_os = "haiku",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         ECANCELED => "Operation canceled",
 
@@ -761,6 +807,7 @@ fn desc(errno: Errno) -> &'static str {
             target_os = "fuchsia",
             target_os = "hurd",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         EOWNERDEAD => "Owner died",
 
@@ -772,6 +819,7 @@ fn desc(errno: Errno) -> &'static str {
             target_os = "aix",
             target_os = "fuchsia",
             target_os = "emscripten",
+            target_os = "cygwin",
         ))]
         ENOTRECOVERABLE => "State not recoverable",
 
@@ -795,10 +843,20 @@ fn desc(errno: Errno) -> &'static str {
         #[cfg(freebsdlike)]
         EDOOFUS => "Programming error",
 
-        #[cfg(any(freebsdlike, target_os = "hurd", target_os = "redox"))]
+        #[cfg(any(
+            freebsdlike,
+            target_os = "hurd",
+            target_os = "redox",
+            target_os = "cygwin"
+        ))]
         EMULTIHOP => "Multihop attempted",
 
-        #[cfg(any(freebsdlike, target_os = "hurd", target_os = "redox"))]
+        #[cfg(any(
+            freebsdlike,
+            target_os = "hurd",
+            target_os = "redox",
+            target_os = "cygwin"
+        ))]
         ENOLINK => "Link has been severed",
 
         #[cfg(target_os = "freebsd")]
@@ -858,11 +916,17 @@ fn desc(errno: Errno) -> &'static str {
             target_os = "aix",
             solarish,
             target_os = "haiku",
-            target_os = "hurd"
+            target_os = "hurd",
+            target_os = "cygwin"
         ))]
         ENOTSUP => "Operation not supported",
 
-        #[cfg(any(bsd, target_os = "aix", target_os = "hurd"))]
+        #[cfg(any(
+            bsd,
+            target_os = "aix",
+            target_os = "hurd",
+            target_os = "cygwin"
+        ))]
         EPROCLIM => "Too many processes",
 
         #[cfg(any(
@@ -910,7 +974,7 @@ fn desc(errno: Errno) -> &'static str {
         #[cfg(any(bsd, target_os = "hurd"))]
         EPROCUNAVAIL => "Bad procedure for program",
 
-        #[cfg(any(bsd, target_os = "hurd"))]
+        #[cfg(any(bsd, target_os = "hurd", target_os = "cygwin"))]
         EFTYPE => "Inappropriate file type or format",
 
         #[cfg(any(bsd, target_os = "hurd"))]
@@ -998,7 +1062,7 @@ fn desc(errno: Errno) -> &'static str {
         #[cfg(target_os = "dragonfly")]
         EASYNC => "Async",
 
-        #[cfg(solarish)]
+        #[cfg(any(solarish, target_os = "cygwin"))]
         EDEADLOCK => "Resource deadlock would occur",
 
         #[cfg(solarish)]
@@ -3526,3 +3590,271 @@ mod consts {
         }
     }
 }
+
+#[cfg(target_os = "cygwin")]
+mod consts {
+    #[derive(Clone, Copy, Debug, Eq, PartialEq)]
+    #[repr(i32)]
+    #[non_exhaustive]
+    pub enum Errno {
+        UnknownErrno = 0,
+        EPERM = libc::EPERM,
+        ENOENT = libc::ENOENT,
+        ESRCH = libc::ESRCH,
+        EINTR = libc::EINTR,
+        EIO = libc::EIO,
+        ENXIO = libc::ENXIO,
+        E2BIG = libc::E2BIG,
+        ENOEXEC = libc::ENOEXEC,
+        EBADF = libc::EBADF,
+        ECHILD = libc::ECHILD,
+        EAGAIN = libc::EAGAIN,
+        ENOMEM = libc::ENOMEM,
+        EACCES = libc::EACCES,
+        EFAULT = libc::EFAULT,
+        ENOTBLK = libc::ENOTBLK,
+        EBUSY = libc::EBUSY,
+        EEXIST = libc::EEXIST,
+        EXDEV = libc::EXDEV,
+        ENODEV = libc::ENODEV,
+        ENOTDIR = libc::ENOTDIR,
+        EISDIR = libc::EISDIR,
+        EINVAL = libc::EINVAL,
+        ENFILE = libc::ENFILE,
+        EMFILE = libc::EMFILE,
+        ENOTTY = libc::ENOTTY,
+        ETXTBSY = libc::ETXTBSY,
+        EFBIG = libc::EFBIG,
+        ENOSPC = libc::ENOSPC,
+        ESPIPE = libc::ESPIPE,
+        EROFS = libc::EROFS,
+        EMLINK = libc::EMLINK,
+        EPIPE = libc::EPIPE,
+        EDOM = libc::EDOM,
+        ERANGE = libc::ERANGE,
+        ENOMSG = libc::ENOMSG,
+        EIDRM = libc::EIDRM,
+        ECHRNG = libc::ECHRNG,
+        EL2NSYNC = libc::EL2NSYNC,
+        EL3HLT = libc::EL3HLT,
+        EL3RST = libc::EL3RST,
+        ELNRNG = libc::ELNRNG,
+        EUNATCH = libc::EUNATCH,
+        ENOCSI = libc::ENOCSI,
+        EL2HLT = libc::EL2HLT,
+        EDEADLK = libc::EDEADLK,
+        ENOLCK = libc::ENOLCK,
+        EBADE = libc::EBADE,
+        EBADR = libc::EBADR,
+        EXFULL = libc::EXFULL,
+        ENOANO = libc::ENOANO,
+        EBADRQC = libc::EBADRQC,
+        EBADSLT = libc::EBADSLT,
+        EDEADLOCK = libc::EDEADLOCK,
+        EBFONT = libc::EBFONT,
+        ENOSTR = libc::ENOSTR,
+        ENODATA = libc::ENODATA,
+        ETIME = libc::ETIME,
+        ENOSR = libc::ENOSR,
+        ENONET = libc::ENONET,
+        ENOPKG = libc::ENOPKG,
+        EREMOTE = libc::EREMOTE,
+        ENOLINK = libc::ENOLINK,
+        EADV = libc::EADV,
+        ESRMNT = libc::ESRMNT,
+        ECOMM = libc::ECOMM,
+        EPROTO = libc::EPROTO,
+        EMULTIHOP = libc::EMULTIHOP,
+        EDOTDOT = libc::EDOTDOT,
+        EBADMSG = libc::EBADMSG,
+        EFTYPE = libc::EFTYPE,
+        ENOTUNIQ = libc::ENOTUNIQ,
+        EBADFD = libc::EBADFD,
+        EREMCHG = libc::EREMCHG,
+        ELIBACC = libc::ELIBACC,
+        ELIBBAD = libc::ELIBBAD,
+        ELIBSCN = libc::ELIBSCN,
+        ELIBMAX = libc::ELIBMAX,
+        ELIBEXEC = libc::ELIBEXEC,
+        ENOSYS = libc::ENOSYS,
+        ENOTEMPTY = libc::ENOTEMPTY,
+        ENAMETOOLONG = libc::ENAMETOOLONG,
+        ELOOP = libc::ELOOP,
+        EOPNOTSUPP = libc::EOPNOTSUPP,
+        EPFNOSUPPORT = libc::EPFNOSUPPORT,
+        ECONNRESET = libc::ECONNRESET,
+        ENOBUFS = libc::ENOBUFS,
+        EAFNOSUPPORT = libc::EAFNOSUPPORT,
+        EPROTOTYPE = libc::EPROTOTYPE,
+        ENOTSOCK = libc::ENOTSOCK,
+        ENOPROTOOPT = libc::ENOPROTOOPT,
+        ESHUTDOWN = libc::ESHUTDOWN,
+        ECONNREFUSED = libc::ECONNREFUSED,
+        EADDRINUSE = libc::EADDRINUSE,
+        ECONNABORTED = libc::ECONNABORTED,
+        ENETUNREACH = libc::ENETUNREACH,
+        ENETDOWN = libc::ENETDOWN,
+        ETIMEDOUT = libc::ETIMEDOUT,
+        EHOSTDOWN = libc::EHOSTDOWN,
+        EHOSTUNREACH = libc::EHOSTUNREACH,
+        EINPROGRESS = libc::EINPROGRESS,
+        EALREADY = libc::EALREADY,
+        EDESTADDRREQ = libc::EDESTADDRREQ,
+        EMSGSIZE = libc::EMSGSIZE,
+        EPROTONOSUPPORT = libc::EPROTONOSUPPORT,
+        ESOCKTNOSUPPORT = libc::ESOCKTNOSUPPORT,
+        EADDRNOTAVAIL = libc::EADDRNOTAVAIL,
+        ENETRESET = libc::ENETRESET,
+        EISCONN = libc::EISCONN,
+        ENOTCONN = libc::ENOTCONN,
+        ETOOMANYREFS = libc::ETOOMANYREFS,
+        EPROCLIM = libc::EPROCLIM,
+        EUSERS = libc::EUSERS,
+        EDQUOT = libc::EDQUOT,
+        ESTALE = libc::ESTALE,
+        ENOTSUP = libc::ENOTSUP,
+        ENOMEDIUM = libc::ENOMEDIUM,
+        EILSEQ = libc::EILSEQ,
+        EOVERFLOW = libc::EOVERFLOW,
+        ECANCELED = libc::ECANCELED,
+        ENOTRECOVERABLE = libc::ENOTRECOVERABLE,
+        EOWNERDEAD = libc::EOWNERDEAD,
+        ESTRPIPE = libc::ESTRPIPE,
+    }
+
+    impl Errno {
+        pub const EWOULDBLOCK: Errno = Errno::EAGAIN;
+        pub const EDEADLOCK: Errno = Errno::EDEADLK;
+        pub const EOPNOTSUPP: Errno = Errno::ENOTSUP;
+    }
+
+    pub const fn from_i32(e: i32) -> Errno {
+        use self::Errno::*;
+
+        match e {
+            libc::EPERM => EPERM,
+            libc::ENOENT => ENOENT,
+            libc::ESRCH => ESRCH,
+            libc::EINTR => EINTR,
+            libc::EIO => EIO,
+            libc::ENXIO => ENXIO,
+            libc::E2BIG => E2BIG,
+            libc::ENOEXEC => ENOEXEC,
+            libc::EBADF => EBADF,
+            libc::ECHILD => ECHILD,
+            libc::EAGAIN => EAGAIN,
+            libc::ENOMEM => ENOMEM,
+            libc::EACCES => EACCES,
+            libc::EFAULT => EFAULT,
+            libc::ENOTBLK => ENOTBLK,
+            libc::EBUSY => EBUSY,
+            libc::EEXIST => EEXIST,
+            libc::EXDEV => EXDEV,
+            libc::ENODEV => ENODEV,
+            libc::ENOTDIR => ENOTDIR,
+            libc::EISDIR => EISDIR,
+            libc::EINVAL => EINVAL,
+            libc::ENFILE => ENFILE,
+            libc::EMFILE => EMFILE,
+            libc::ENOTTY => ENOTTY,
+            libc::ETXTBSY => ETXTBSY,
+            libc::EFBIG => EFBIG,
+            libc::ENOSPC => ENOSPC,
+            libc::ESPIPE => ESPIPE,
+            libc::EROFS => EROFS,
+            libc::EMLINK => EMLINK,
+            libc::EPIPE => EPIPE,
+            libc::EDOM => EDOM,
+            libc::ERANGE => ERANGE,
+            libc::ENOMSG => ENOMSG,
+            libc::EIDRM => EIDRM,
+            libc::ECHRNG => ECHRNG,
+            libc::EL2NSYNC => EL2NSYNC,
+            libc::EL3HLT => EL3HLT,
+            libc::EL3RST => EL3RST,
+            libc::ELNRNG => ELNRNG,
+            libc::EUNATCH => EUNATCH,
+            libc::ENOCSI => ENOCSI,
+            libc::EL2HLT => EL2HLT,
+            libc::EDEADLK => EDEADLK,
+            libc::ENOLCK => ENOLCK,
+            libc::EBADE => EBADE,
+            libc::EBADR => EBADR,
+            libc::EXFULL => EXFULL,
+            libc::ENOANO => ENOANO,
+            libc::EBADRQC => EBADRQC,
+            libc::EBADSLT => EBADSLT,
+            libc::EDEADLOCK => EDEADLOCK,
+            libc::EBFONT => EBFONT,
+            libc::ENOSTR => ENOSTR,
+            libc::ENODATA => ENODATA,
+            libc::ETIME => ETIME,
+            libc::ENOSR => ENOSR,
+            libc::ENONET => ENONET,
+            libc::ENOPKG => ENOPKG,
+            libc::EREMOTE => EREMOTE,
+            libc::ENOLINK => ENOLINK,
+            libc::EADV => EADV,
+            libc::ESRMNT => ESRMNT,
+            libc::ECOMM => ECOMM,
+            libc::EPROTO => EPROTO,
+            libc::EMULTIHOP => EMULTIHOP,
+            libc::EDOTDOT => EDOTDOT,
+            libc::EBADMSG => EBADMSG,
+            libc::EFTYPE => EFTYPE,
+            libc::ENOTUNIQ => ENOTUNIQ,
+            libc::EBADFD => EBADFD,
+            libc::EREMCHG => EREMCHG,
+            libc::ELIBACC => ELIBACC,
+            libc::ELIBBAD => ELIBBAD,
+            libc::ELIBSCN => ELIBSCN,
+            libc::ELIBMAX => ELIBMAX,
+            libc::ELIBEXEC => ELIBEXEC,
+            libc::ENOSYS => ENOSYS,
+            libc::ENOTEMPTY => ENOTEMPTY,
+            libc::ENAMETOOLONG => ENAMETOOLONG,
+            libc::ELOOP => ELOOP,
+            libc::EOPNOTSUPP => EOPNOTSUPP,
+            libc::EPFNOSUPPORT => EPFNOSUPPORT,
+            libc::ECONNRESET => ECONNRESET,
+            libc::ENOBUFS => ENOBUFS,
+            libc::EAFNOSUPPORT => EAFNOSUPPORT,
+            libc::EPROTOTYPE => EPROTOTYPE,
+            libc::ENOTSOCK => ENOTSOCK,
+            libc::ENOPROTOOPT => ENOPROTOOPT,
+            libc::ESHUTDOWN => ESHUTDOWN,
+            libc::ECONNREFUSED => ECONNREFUSED,
+            libc::EADDRINUSE => EADDRINUSE,
+            libc::ECONNABORTED => ECONNABORTED,
+            libc::ENETUNREACH => ENETUNREACH,
+            libc::ENETDOWN => ENETDOWN,
+            libc::ETIMEDOUT => ETIMEDOUT,
+            libc::EHOSTDOWN => EHOSTDOWN,
+            libc::EHOSTUNREACH => EHOSTUNREACH,
+            libc::EINPROGRESS => EINPROGRESS,
+            libc::EALREADY => EALREADY,
+            libc::EDESTADDRREQ => EDESTADDRREQ,
+            libc::EMSGSIZE => EMSGSIZE,
+            libc::EPROTONOSUPPORT => EPROTONOSUPPORT,
+            libc::ESOCKTNOSUPPORT => ESOCKTNOSUPPORT,
+            libc::EADDRNOTAVAIL => EADDRNOTAVAIL,
+            libc::ENETRESET => ENETRESET,
+            libc::EISCONN => EISCONN,
+            libc::ENOTCONN => ENOTCONN,
+            libc::ETOOMANYREFS => ETOOMANYREFS,
+            libc::EPROCLIM => EPROCLIM,
+            libc::EUSERS => EUSERS,
+            libc::EDQUOT => EDQUOT,
+            libc::ESTALE => ESTALE,
+            libc::ENOTSUP => ENOTSUP,
+            libc::ENOMEDIUM => ENOMEDIUM,
+            libc::EILSEQ => EILSEQ,
+            libc::EOVERFLOW => EOVERFLOW,
+            libc::ECANCELED => ECANCELED,
+            libc::ENOTRECOVERABLE => ENOTRECOVERABLE,
+            libc::EOWNERDEAD => EOWNERDEAD,
+            libc::ESTRPIPE => ESTRPIPE,
+            _ => UnknownErrno,
+        }
+    }
+}
diff --git a/src/fcntl.rs b/src/fcntl.rs
index 68140966a3..13ee1919ca 100644
--- a/src/fcntl.rs
+++ b/src/fcntl.rs
@@ -128,7 +128,8 @@ libc_bitflags!(
         #[cfg(not(any(
             solarish,
             target_os = "aix",
-            target_os = "haiku"
+            target_os = "haiku",
+            target_os = "cygwin"
         )))]
         O_ASYNC;
         /// Closes the file descriptor once an `execve` call is made.
@@ -173,7 +174,7 @@ libc_bitflags!(
         #[cfg(not(target_os = "redox"))]
         O_NOCTTY;
         /// Same as `O_NONBLOCK`.
-        #[cfg(not(any(target_os = "redox", target_os = "haiku")))]
+        #[cfg(not(any(target_os = "redox", target_os = "haiku", target_os = "cygwin")))]
         O_NDELAY;
         /// `open()` will fail if the given path is a symbolic link.
         O_NOFOLLOW;
diff --git a/src/sys/resource.rs b/src/sys/resource.rs
index 73d8a05e0f..449698dbe2 100644
--- a/src/sys/resource.rs
+++ b/src/sys/resource.rs
@@ -19,7 +19,8 @@ cfg_if! {
         bsd,
         target_os = "android",
         target_os = "aix",
-        all(target_os = "linux", not(target_env = "gnu"))
+        all(target_os = "linux", not(target_env = "gnu")),
+        target_os = "cygwin"
     ))]{
         use libc::rlimit;
     }
@@ -49,7 +50,8 @@ libc_enum! {
             bsd,
             target_os = "android",
             target_os = "aix",
-            all(target_os = "linux", not(any(target_env = "gnu", target_env = "uclibc")))
+            all(target_os = "linux", not(any(target_env = "gnu", target_env = "uclibc"))),
+            target_os = "cygwin"
         ), repr(i32))]
     #[non_exhaustive]
     pub enum Resource {
diff --git a/src/unistd.rs b/src/unistd.rs
index 4bb715b707..172cb4a6b0 100644
--- a/src/unistd.rs
+++ b/src/unistd.rs
@@ -16,6 +16,7 @@ use crate::fcntl::AtFlags;
     target_os = "fuchsia",
     target_os = "hurd",
     target_os = "redox",
+    target_os = "cygwin",
 ))]
 use crate::fcntl::OFlag;
 #[cfg(all(feature = "fs", bsd))]
@@ -1494,6 +1495,7 @@ feature! {
     target_os = "hurd",
     target_os = "redox",
     netbsdlike,
+    target_os = "cygwin",
 ))]
 pub fn pipe2(flags: OFlag) -> Result<(std::os::fd::OwnedFd, std::os::fd::OwnedFd)> {
     let mut fds = mem::MaybeUninit::<[std::os::fd::OwnedFd; 2]>::uninit();

From 1cb3fab2ea481259d7aeb2e486e67ae5bccb7835 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E7=8E=8B=E5=AE=87=E9=80=B8?= <Strawberry_Str@hotmail.com>
Date: Fri, 7 Mar 2025 23:42:56 +0800
Subject: [PATCH 02/14] Remove no_mangle

---
 src/errno.rs | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/errno.rs b/src/errno.rs
index 0d9d2d0fa0..d7d3926d30 100644
--- a/src/errno.rs
+++ b/src/errno.rs
@@ -25,7 +25,6 @@ cfg_if! {
             unsafe { libc::__error() }
         }
     } else if #[cfg(any(target_os = "android", netbsdlike, target_os = "cygwin"))] {
-        #[cfg_attr(target_os = "cygwin", no_mangle)]
         unsafe fn errno_location() -> *mut c_int {
             unsafe { libc::__errno() }
         }

From 174890720bf640ccb8dcdd8556f697d30363f764 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E7=8E=8B=E5=AE=87=E9=80=B8?= <Strawberry_Str@hotmail.com>
Date: Fri, 7 Mar 2025 23:52:09 +0800
Subject: [PATCH 03/14] Add check-cfg for cygwin target

---
 build.rs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/build.rs b/build.rs
index 6586cee48e..eb279438f5 100644
--- a/build.rs
+++ b/build.rs
@@ -30,4 +30,6 @@ fn main() {
     // Below are custom cfg values set during some CI steps.
     println!("cargo:rustc-check-cfg=cfg(fbsd14)");
     println!("cargo:rustc-check-cfg=cfg(qemu)");
+    // Cygwin target, added in 1.86
+    println!("cargo:rustc-check-cfg=cfg(target_os, values(\"cygwin\"))");
 }

From f0e9e406bd04f19fa77034245ae4462c390205ec Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E7=8E=8B=E5=AE=87=E9=80=B8?= <Strawberry_Str@hotmail.com>
Date: Sat, 8 Mar 2025 23:34:39 +0800
Subject: [PATCH 04/14] feat: full cygwin support

---
 src/dir.rs                |  1 +
 src/features.rs           |  1 +
 src/net/if_.rs            | 13 ++++++++-----
 src/sys/mman.rs           |  8 ++++----
 src/sys/signal.rs         | 13 ++++++++-----
 src/sys/socket/addr.rs    | 13 +++++++++----
 src/sys/socket/mod.rs     | 14 +++++++++-----
 src/sys/socket/sockopt.rs |  5 +++--
 src/sys/termios.rs        |  6 +++---
 src/sys/uio.rs            |  4 ++--
 src/syslog.rs             |  2 +-
 src/unistd.rs             | 16 +++++++++++++---
 12 files changed, 62 insertions(+), 34 deletions(-)

diff --git a/src/dir.rs b/src/dir.rs
index d146b4f126..b514212e60 100644
--- a/src/dir.rs
+++ b/src/dir.rs
@@ -287,6 +287,7 @@ impl Entry {
                          target_os = "fuchsia",
                          target_os = "haiku",
                          target_os = "hurd",
+                         target_os = "cygwin",
                          solarish,
                          linux_android,
                          apple_targets))] {
diff --git a/src/features.rs b/src/features.rs
index b71d42e83c..b472f803a7 100644
--- a/src/features.rs
+++ b/src/features.rs
@@ -103,6 +103,7 @@ mod os {
         target_os = "hurd",         // Since glibc 2.28
         target_os = "illumos",      // Since ???
         target_os = "redox",        // Since 1-july-2020
+        target_os = "cygwin",
 ))]
 mod os {
     /// Check if the OS supports atomic close-on-exec for sockets
diff --git a/src/net/if_.rs b/src/net/if_.rs
index 5b6c2e77a5..cae6e3f826 100644
--- a/src/net/if_.rs
+++ b/src/net/if_.rs
@@ -51,7 +51,7 @@ libc_bitflags!(
         IFF_BROADCAST as IflagsType;
         /// Internal debugging flag. (see
         /// [`netdevice(7)`](https://man7.org/linux/man-pages/man7/netdevice.7.html))
-        #[cfg(not(target_os = "haiku"))]
+        #[cfg(not(any(target_os = "haiku", target_os = "cygwin")))]
         IFF_DEBUG as IflagsType;
         /// Interface is a loopback interface. (see
         /// [`netdevice(7)`](https://man7.org/linux/man-pages/man7/netdevice.7.html))
@@ -66,7 +66,8 @@ libc_bitflags!(
                   solarish,
                   apple_targets,
                   target_os = "fuchsia",
-                  target_os = "netbsd"))]
+                  target_os = "netbsd",
+                  target_os = "cygwin"))]
         IFF_NOTRAILERS as IflagsType;
         /// Interface manages own routes.
         #[cfg(any(target_os = "dragonfly"))]
@@ -77,7 +78,8 @@ libc_bitflags!(
                   linux_android,
                   bsd,
                   solarish,
-                  target_os = "fuchsia"))]
+                  target_os = "fuchsia",
+                  target_os = "cygwin"))]
         IFF_RUNNING as IflagsType;
         /// No arp protocol, L2 destination address not set. (see
         /// [`netdevice(7)`](https://man7.org/linux/man-pages/man7/netdevice.7.html))
@@ -87,6 +89,7 @@ libc_bitflags!(
         IFF_PROMISC as IflagsType;
         /// Receive all multicast packets. (see
         /// [`netdevice(7)`](https://man7.org/linux/man-pages/man7/netdevice.7.html))
+        #[cfg(not(target_os = "cygwin"))]
         IFF_ALLMULTI as IflagsType;
         /// Master of a load balancing bundle. (see
         /// [`netdevice(7)`](https://man7.org/linux/man-pages/man7/netdevice.7.html))
@@ -145,7 +148,7 @@ libc_bitflags!(
         #[cfg(solarish)]
         IFF_PRIVATE as IflagsType;
         /// Driver signals L1 up. Volatile.
-        #[cfg(any(target_os = "fuchsia", target_os = "linux"))]
+        #[cfg(any(target_os = "fuchsia", target_os = "linux", target_os = "cygwin"))]
         IFF_LOWER_UP;
         /// Interface is in polling mode.
         #[cfg(any(target_os = "dragonfly"))]
@@ -157,7 +160,7 @@ libc_bitflags!(
         #[cfg(solarish)]
         IFF_NOXMIT as IflagsType;
         /// Driver signals dormant. Volatile.
-        #[cfg(any(target_os = "fuchsia", target_os = "linux"))]
+        #[cfg(any(target_os = "fuchsia", target_os = "linux", target_os = "cygwin"))]
         IFF_DORMANT;
         /// User-requested promisc mode.
         #[cfg(freebsdlike)]
diff --git a/src/sys/mman.rs b/src/sys/mman.rs
index ac142316b1..06507ef65b 100644
--- a/src/sys/mman.rs
+++ b/src/sys/mman.rs
@@ -281,7 +281,7 @@ libc_enum! {
         #[cfg(linux_android)]
         MADV_DODUMP,
         /// Specify that the application no longer needs the pages in the given range.
-        #[cfg(not(any(target_os = "aix", target_os = "hurd")))]
+        #[cfg(not(any(target_os = "aix", target_os = "hurd", target_os = "cygwin")))]
         MADV_FREE,
         /// Request that the system not flush the current range to disk unless it needs to.
         #[cfg(freebsdlike)]
@@ -357,7 +357,7 @@ libc_bitflags! {
     }
 }
 
-#[cfg(not(target_os = "haiku"))]
+#[cfg(not(any(target_os = "haiku", target_os = "cygwin")))]
 libc_bitflags! {
     /// Flags for [`mlockall`].
     pub struct MlockAllFlags: c_int {
@@ -400,7 +400,7 @@ pub unsafe fn munlock(addr: NonNull<c_void>, length: size_t) -> Result<()> {
 /// Locked pages never move to the swap area. For more information, see [`mlockall(2)`].
 ///
 /// [`mlockall(2)`]: https://man7.org/linux/man-pages/man2/mlockall.2.html
-#[cfg(not(target_os = "haiku"))]
+#[cfg(not(any(target_os = "haiku", target_os = "cygwin")))]
 pub fn mlockall(flags: MlockAllFlags) -> Result<()> {
     unsafe { Errno::result(libc::mlockall(flags.bits())) }.map(drop)
 }
@@ -410,7 +410,7 @@ pub fn mlockall(flags: MlockAllFlags) -> Result<()> {
 /// For more information, see [`munlockall(2)`].
 ///
 /// [`munlockall(2)`]: https://man7.org/linux/man-pages/man2/munlockall.2.html
-#[cfg(not(target_os = "haiku"))]
+#[cfg(not(any(target_os = "haiku", target_os = "cygwin")))]
 pub fn munlockall() -> Result<()> {
     unsafe { Errno::result(libc::munlockall()) }.map(drop)
 }
diff --git a/src/sys/signal.rs b/src/sys/signal.rs
index c1a2ac6deb..bc920dbf17 100644
--- a/src/sys/signal.rs
+++ b/src/sys/signal.rs
@@ -111,7 +111,7 @@ libc_enum! {
         #[cfg(not(any(linux_android, target_os = "emscripten",
                       target_os = "fuchsia", target_os = "redox",
                       target_os = "haiku", target_os = "aix",
-                      target_os = "solaris")))]
+                      target_os = "solaris", target_os = "cygwin")))]
         /// Information request
         SIGINFO,
     }
@@ -190,7 +190,8 @@ impl FromStr for Signal {
                 target_os = "redox",
                 target_os = "aix",
                 target_os = "haiku",
-                target_os = "solaris"
+                target_os = "solaris",
+                target_os = "cygwin"
             )))]
             "SIGINFO" => Signal::SIGINFO,
             _ => return Err(Errno::EINVAL),
@@ -275,7 +276,8 @@ impl Signal {
                 target_os = "redox",
                 target_os = "aix",
                 target_os = "haiku",
-                target_os = "solaris"
+                target_os = "solaris",
+                target_os = "cygwin"
             )))]
             Signal::SIGINFO => "SIGINFO",
         }
@@ -359,7 +361,7 @@ const SIGNALS: [Signal; 30] = [
     SIGURG, SIGPOLL, SIGIO, SIGSTOP, SIGTSTP, SIGCONT, SIGTTIN, SIGTTOU,
     SIGVTALRM, SIGPROF, SIGXCPU, SIGXFSZ, SIGTRAP,
 ];
-#[cfg(target_os = "solaris")]
+#[cfg(any(target_os = "solaris", target_os = "cygwin"))]
 #[cfg(feature = "signal")]
 const SIGNALS: [Signal; 30] = [
     SIGHUP, SIGINT, SIGQUIT, SIGILL, SIGTRAP, SIGABRT, SIGBUS, SIGFPE, SIGKILL,
@@ -374,7 +376,8 @@ const SIGNALS: [Signal; 30] = [
     target_os = "aix",
     target_os = "redox",
     target_os = "haiku",
-    target_os = "solaris"
+    target_os = "solaris",
+    target_os = "cygwin"
 )))]
 #[cfg(feature = "signal")]
 const SIGNALS: [Signal; 31] = [
diff --git a/src/sys/socket/addr.rs b/src/sys/socket/addr.rs
index ac3a234704..fdaff3660b 100644
--- a/src/sys/socket/addr.rs
+++ b/src/sys/socket/addr.rs
@@ -66,7 +66,7 @@ pub enum AddressFamily {
     #[cfg(linux_android)]
     Netlink = libc::AF_NETLINK,
     /// Kernel interface for interacting with the routing table
-    #[cfg(not(any(linux_android, target_os = "redox")))]
+    #[cfg(not(any(linux_android, target_os = "redox", target_os = "cygwin")))]
     Route = libc::PF_ROUTE,
     /// Low level packet interface (see [`packet(7)`](https://man7.org/linux/man-pages/man7/packet.7.html))
     #[cfg(any(linux_android, solarish, target_os = "fuchsia"))]
@@ -78,7 +78,7 @@ pub enum AddressFamily {
     #[cfg(linux_android)]
     Ax25 = libc::AF_AX25,
     /// IPX - Novell protocols
-    #[cfg(not(any(target_os = "aix", target_os = "redox")))]
+    #[cfg(not(any(target_os = "aix", target_os = "redox", target_os = "cygwin")))]
     Ipx = libc::AF_IPX,
     /// AppleTalk
     #[cfg(not(target_os = "redox"))]
@@ -164,6 +164,7 @@ pub enum AddressFamily {
         apple_targets,
         target_os = "hurd",
         target_os = "redox",
+        target_os = "cygwin",
     )))]
     Bluetooth = libc::AF_BLUETOOTH,
     /// IUCV (inter-user communication vehicle) z/VM protocol for
@@ -180,6 +181,7 @@ pub enum AddressFamily {
         target_os = "haiku",
         target_os = "hurd",
         target_os = "redox",
+        target_os = "cygwin",
     )))]
     Isdn = libc::AF_ISDN,
     /// Nokia cellular modem IPC/RPC interface
@@ -263,7 +265,7 @@ impl AddressFamily {
             libc::AF_NETLINK => Some(AddressFamily::Netlink),
             #[cfg(apple_targets)]
             libc::AF_SYSTEM => Some(AddressFamily::System),
-            #[cfg(not(any(linux_android, target_os = "redox")))]
+            #[cfg(not(any(linux_android, target_os = "redox", target_os = "cygwin")))]
             libc::PF_ROUTE => Some(AddressFamily::Route),
             #[cfg(linux_android)]
             libc::AF_PACKET => Some(AddressFamily::Packet),
@@ -446,6 +448,7 @@ impl UnixAddr {
                      target_os = "fuchsia",
                      solarish,
                      target_os = "redox",
+                     target_os = "cygwin",
                 ))]
             {
                 UnixAddr { sun, sun_len }
@@ -510,6 +513,7 @@ impl UnixAddr {
                      target_os = "fuchsia",
                      solarish,
                      target_os = "redox",
+                     target_os = "cygwin",
                 ))]
             {
                 self.sun_len
@@ -556,6 +560,7 @@ impl SockaddrLike for UnixAddr {
                          target_os = "fuchsia",
                          solarish,
                          target_os = "redox",
+                         target_os = "cygwin",
                 ))] {
                 let su_len = len.unwrap_or(
                     mem::size_of::<libc::sockaddr_un>() as libc::socklen_t
@@ -1122,7 +1127,7 @@ pub union SockaddrStorage {
     alg: AlgAddr,
     #[cfg(all(
         feature = "net",
-        not(any(target_os = "hurd", target_os = "redox"))
+        not(any(target_os = "hurd", target_os = "redox", target_os = "cygwin"))
     ))]
     #[cfg_attr(docsrs, doc(cfg(feature = "net")))]
     dl: LinkAddr,
diff --git a/src/sys/socket/mod.rs b/src/sys/socket/mod.rs
index e26e327d78..ffea1144b0 100644
--- a/src/sys/socket/mod.rs
+++ b/src/sys/socket/mod.rs
@@ -43,7 +43,8 @@ pub use self::addr::{AddressFamily, UnixAddr};
     solarish,
     target_os = "haiku",
     target_os = "hurd",
-    target_os = "redox"
+    target_os = "redox",
+    target_os = "cygwin",
 )))]
 #[cfg(feature = "net")]
 pub use self::addr::{LinkAddr, SockaddrIn, SockaddrIn6};
@@ -51,7 +52,8 @@ pub use self::addr::{LinkAddr, SockaddrIn, SockaddrIn6};
     solarish,
     target_os = "haiku",
     target_os = "hurd",
-    target_os = "redox"
+    target_os = "redox",
+    target_os = "cygwin",
 ))]
 #[cfg(feature = "net")]
 pub use self::addr::{SockaddrIn, SockaddrIn6};
@@ -1023,7 +1025,7 @@ impl ControlMessageOwned {
                 let cred: libc::cmsgcred = unsafe { ptr::read_unaligned(p as *const _) };
                 ControlMessageOwned::ScmCreds(cred.into())
             }
-            #[cfg(not(any(target_os = "aix", target_os = "haiku")))]
+            #[cfg(not(any(target_os = "aix", target_os = "haiku", target_os = "cygwin")))]
             (libc::SOL_SOCKET, libc::SCM_TIMESTAMP) => {
                 let tv: libc::timeval = unsafe { ptr::read_unaligned(p as *const _) };
                 ControlMessageOwned::ScmTimestamp(TimeVal::from(tv))
@@ -1372,13 +1374,15 @@ impl ControlMessage<'_> {
     /// The value of CMSG_LEN on this message.
     /// Safe because CMSG_LEN is always safe
     #[cfg(any(target_os = "android",
-              all(target_os = "linux", not(any(target_env = "musl", target_env = "ohos")))))]
+              all(target_os = "linux", not(any(target_env = "musl", target_env = "ohos"))),
+              target_os = "cygwin"))]
     fn cmsg_len(&self) -> usize {
         unsafe{CMSG_LEN(self.len() as libc::c_uint) as usize}
     }
 
     #[cfg(not(any(target_os = "android",
-              all(target_os = "linux", not(any(target_env = "musl", target_env = "ohos"))))))]
+              all(target_os = "linux", not(any(target_env = "musl", target_env = "ohos"))),
+              target_os = "cygwin")))]
     fn cmsg_len(&self) -> libc::c_uint {
         unsafe{CMSG_LEN(self.len() as libc::c_uint)}
     }
diff --git a/src/sys/socket/sockopt.rs b/src/sys/socket/sockopt.rs
index 11c3be9e13..f1bebddfaf 100644
--- a/src/sys/socket/sockopt.rs
+++ b/src/sys/socket/sockopt.rs
@@ -298,7 +298,7 @@ sockopt_impl!(
     libc::SO_REUSEADDR,
     bool
 );
-#[cfg(not(solarish))]
+#[cfg(not(any(solarish, target_os = "cygwin")))]
 sockopt_impl!(
     /// Permits multiple AF_INET or AF_INET6 sockets to be bound to an
     /// identical socket address.
@@ -883,7 +883,8 @@ sockopt_impl!(
     target_os = "aix",
     target_os = "haiku",
     target_os = "hurd",
-    target_os = "redox"
+    target_os = "redox",
+    target_os = "cygwin"
 )))]
 sockopt_impl!(
     /// Enable or disable the receiving of the `SO_TIMESTAMP` control message.
diff --git a/src/sys/termios.rs b/src/sys/termios.rs
index b69bc178d8..b2415c0aff 100644
--- a/src/sys/termios.rs
+++ b/src/sys/termios.rs
@@ -667,7 +667,7 @@ libc_bitflags! {
         ECHOK;
         ECHO;
         ECHONL;
-        #[cfg(not(target_os = "redox"))]
+        #[cfg(not(any(target_os = "redox", target_os = "cygwin")))]
         ECHOPRT;
         #[cfg(not(target_os = "redox"))]
         ECHOCTL;
@@ -676,14 +676,14 @@ libc_bitflags! {
         #[cfg(bsd)]
         ALTWERASE;
         IEXTEN;
-        #[cfg(not(any(target_os = "redox", target_os = "haiku", target_os = "aix")))]
+        #[cfg(not(any(target_os = "redox", target_os = "haiku", target_os = "aix", target_os = "cygwin")))]
         EXTPROC;
         TOSTOP;
         #[cfg(not(target_os = "redox"))]
         FLUSHO;
         #[cfg(bsd)]
         NOKERNINFO;
-        #[cfg(not(target_os = "redox"))]
+        #[cfg(not(any(target_os = "redox", target_os = "cygwin")))]
         PENDIN;
         NOFLSH;
     }
diff --git a/src/sys/uio.rs b/src/sys/uio.rs
index cdf380dd11..f47083cba4 100644
--- a/src/sys/uio.rs
+++ b/src/sys/uio.rs
@@ -53,7 +53,7 @@ pub fn readv<Fd: AsFd>(fd: Fd, iov: &mut [IoSliceMut<'_>]) -> Result<usize> {
 /// or an error occurs. The file offset is not changed.
 ///
 /// See also: [`writev`](fn.writev.html) and [`pwrite`](fn.pwrite.html)
-#[cfg(not(any(target_os = "redox", target_os = "haiku", target_os = "solaris")))]
+#[cfg(not(any(target_os = "redox", target_os = "haiku", target_os = "solaris", target_os = "cygwin")))]
 pub fn pwritev<Fd: AsFd>(
     fd: Fd,
     iov: &[IoSlice<'_>],
@@ -82,7 +82,7 @@ pub fn pwritev<Fd: AsFd>(
 /// changed.
 ///
 /// See also: [`readv`](fn.readv.html) and [`pread`](fn.pread.html)
-#[cfg(not(any(target_os = "redox", target_os = "haiku", target_os = "solaris")))]
+#[cfg(not(any(target_os = "redox", target_os = "haiku", target_os = "solaris", target_os = "cygwin")))]
 // Clippy doesn't know that we need to pass iov mutably only because the
 // mutation happens after converting iov to a pointer
 #[allow(clippy::needless_pass_by_ref_mut)]
diff --git a/src/syslog.rs b/src/syslog.rs
index 05143252d4..7894978029 100644
--- a/src/syslog.rs
+++ b/src/syslog.rs
@@ -215,7 +215,7 @@ libc_bitflags! {
         /// which file descriptors are allocated.
         LOG_NDELAY;
         /// Write the message to standard error output as well to the system log.
-        #[cfg(not(any(solarish, target_os = "redox")))]
+        #[cfg(not(any(solarish, target_os = "redox", target_os = "cygwin")))]
         LOG_PERROR;
     }
 }
diff --git a/src/unistd.rs b/src/unistd.rs
index 172cb4a6b0..8995fbe02e 100644
--- a/src/unistd.rs
+++ b/src/unistd.rs
@@ -1945,7 +1945,8 @@ pub fn setgroups(groups: &[Gid]) -> Result<()> {
     cfg_if! {
         if #[cfg(any(bsd,
                      solarish,
-                     target_os = "aix"))] {
+                     target_os = "aix",
+                     target_os = "cygwin"))] {
             type setgroups_ngroups_t = c_int;
         } else {
             type setgroups_ngroups_t = size_t;
@@ -2208,7 +2209,7 @@ feature! {
 #![feature = "acct"]
 
 /// Process accounting
-#[cfg(not(any(target_os = "redox", target_os = "haiku")))]
+#[cfg(not(any(target_os = "redox", target_os = "haiku", target_os = "cygwin")))]
 pub mod acct {
     use crate::errno::Errno;
     use crate::{NixPath, Result};
@@ -3499,6 +3500,7 @@ pub struct User {
         target_os = "haiku",
         target_os = "hurd",
         target_os = "emscripten",
+        target_os = "cygwin",
     )))]
     pub class: CString,
     /// Last password change
@@ -3510,6 +3512,7 @@ pub struct User {
         target_os = "haiku",
         target_os = "hurd",
         target_os = "emscripten",
+        target_os = "cygwin",
     )))]
     pub change: libc::time_t,
     /// Expiration time of account
@@ -3521,6 +3524,7 @@ pub struct User {
         target_os = "haiku",
         target_os = "hurd",
         target_os = "emscripten",
+        target_os = "cygwin",
     )))]
     pub expire: libc::time_t,
 }
@@ -3575,6 +3579,7 @@ impl From<&libc::passwd> for User {
                     target_os = "haiku",
                     target_os = "hurd",
                     target_os = "emscripten",
+                    target_os = "cygwin",
                 )))]
                 class: CString::new(CStr::from_ptr(pw.pw_class).to_bytes())
                     .unwrap(),
@@ -3586,6 +3591,7 @@ impl From<&libc::passwd> for User {
                     target_os = "haiku",
                     target_os = "hurd",
                     target_os = "emscripten",
+                    target_os = "cygwin",
                 )))]
                 change: pw.pw_change,
                 #[cfg(not(any(
@@ -3596,6 +3602,7 @@ impl From<&libc::passwd> for User {
                     target_os = "haiku",
                     target_os = "hurd",
                     target_os = "emscripten",
+                    target_os = "cygwin",
                 )))]
                 expire: pw.pw_expire,
             }
@@ -3638,6 +3645,7 @@ impl From<User> for libc::passwd {
                 target_os = "haiku",
                 target_os = "hurd",
                 target_os = "emscripten",
+                target_os = "cygwin",
             )))]
             pw_class: u.class.into_raw(),
             #[cfg(not(any(
@@ -3648,6 +3656,7 @@ impl From<User> for libc::passwd {
                 target_os = "haiku",
                 target_os = "hurd",
                 target_os = "emscripten",
+                target_os = "cygwin",
             )))]
             pw_change: u.change,
             #[cfg(not(any(
@@ -3658,11 +3667,12 @@ impl From<User> for libc::passwd {
                 target_os = "haiku",
                 target_os = "hurd",
                 target_os = "emscripten",
+                target_os = "cygwin",
             )))]
             pw_expire: u.expire,
             #[cfg(solarish)]
             pw_age: CString::new("").unwrap().into_raw(),
-            #[cfg(solarish)]
+            #[cfg(any(solarish, target_os = "cygwin"))]
             pw_comment: CString::new("").unwrap().into_raw(),
             #[cfg(freebsdlike)]
             pw_fields: 0,

From 2cc5c7674ead64611e9d24b55ca0b97fa1d52657 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E7=8E=8B=E5=AE=87=E9=80=B8?= <Strawberry_Str@hotmail.com>
Date: Tue, 11 Mar 2025 22:52:15 +0800
Subject: [PATCH 05/14] feat: update libc to add cygwin support

---
 Cargo.toml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Cargo.toml b/Cargo.toml
index c6690d46ef..559f0b6a45 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -28,7 +28,7 @@ targets = [
 ]
 
 [dependencies]
-libc = { version = "0.2.166", features = ["extra_traits"] }
+libc = { version = "0.2.171", features = ["extra_traits"] }
 bitflags = "2.3.3"
 cfg-if = "1.0"
 pin-utils = { version = "0.1.0", optional = true }

From e0f3f24be6ba0799a3db2f953c98d19abe4d2d58 Mon Sep 17 00:00:00 2001
From: Berrysoft <Strawberry_Str@hotmail.com>
Date: Wed, 12 Mar 2025 13:09:53 +0800
Subject: [PATCH 06/14] feat: add statfs support for cygwin

---
 src/sys/mod.rs    |  2 +-
 src/sys/statfs.rs | 25 ++++++++++++++++---------
 2 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/src/sys/mod.rs b/src/sys/mod.rs
index d4ad851f35..95ad68b4ad 100644
--- a/src/sys/mod.rs
+++ b/src/sys/mod.rs
@@ -137,7 +137,7 @@ feature! {
     pub mod stat;
 }
 
-#[cfg(any(linux_android, freebsdlike, apple_targets, target_os = "openbsd"))]
+#[cfg(any(linux_android, freebsdlike, apple_targets, target_os = "openbsd", target_os = "cygwin"))]
 feature! {
     #![feature = "fs"]
     pub mod statfs;
diff --git a/src/sys/statfs.rs b/src/sys/statfs.rs
index 3b019dbd05..c0a9f6c993 100644
--- a/src/sys/statfs.rs
+++ b/src/sys/statfs.rs
@@ -1,7 +1,7 @@
 //! Get filesystem statistics, non-portably
 //!
 //! See [`statvfs`](crate::sys::statvfs) for a portable alternative.
-#[cfg(not(linux_android))]
+#[cfg(not(any(linux_android, target_os = "cygwin")))]
 use std::ffi::CStr;
 use std::fmt::{self, Debug};
 use std::mem;
@@ -19,8 +19,11 @@ use crate::{errno::Errno, NixPath, Result};
 #[cfg(target_os = "android")]
 pub type fsid_t = libc::__fsid_t;
 /// Identifies a mounted file system
-#[cfg(not(target_os = "android"))]
+#[cfg(not(any(target_os = "android", target_os = "cygwin")))]
 pub type fsid_t = libc::fsid_t;
+/// Identifies a mounted file system
+#[cfg(target_os = "cygwin")]
+pub type fsid_t = libc::c_long;
 
 cfg_if! {
     if #[cfg(any(linux_android, target_os = "fuchsia"))] {
@@ -71,6 +74,8 @@ type fs_type_t = libc::c_int;
     ))
 ))]
 type fs_type_t = libc::__fsword_t;
+#[cfg(target_os = "cygwin")]
+type fs_type_t = libc::c_long;
 
 /// Describes the file system type as known by the operating system.
 #[cfg(any(
@@ -83,6 +88,7 @@ type fs_type_t = libc::__fsword_t;
         target_os = "linux",
         not(any(target_arch = "s390x", target_env = "musl"))
     ),
+    target_os = "cygwin",
 ))]
 #[derive(Eq, Copy, Clone, PartialEq, Debug)]
 pub struct FsType(pub fs_type_t);
@@ -301,7 +307,7 @@ impl Statfs {
     }
 
     /// Magic code defining system type
-    #[cfg(not(linux_android))]
+    #[cfg(not(any(linux_android, target_os = "cygwin")))]
     pub fn filesystem_type_name(&self) -> &str {
         let c_str = unsafe { CStr::from_ptr(self.0.f_fstypename.as_ptr()) };
         c_str.to_str().unwrap()
@@ -437,7 +443,7 @@ impl Statfs {
     }
 
     /// Size of a block
-    #[cfg(target_os = "dragonfly")]
+    #[cfg(any(target_os = "dragonfly", target_os = "cygwin"))]
     pub fn block_size(&self) -> libc::c_long {
         self.0.f_bsize
     }
@@ -518,7 +524,7 @@ impl Statfs {
     }
 
     /// Total data blocks in filesystem
-    #[cfg(target_os = "dragonfly")]
+    #[cfg(any(target_os = "dragonfly", target_os = "cygwin"))]
     pub fn blocks(&self) -> libc::c_long {
         self.0.f_blocks
     }
@@ -542,7 +548,7 @@ impl Statfs {
     }
 
     /// Free blocks in filesystem
-    #[cfg(target_os = "dragonfly")]
+    #[cfg(any(target_os = "dragonfly", target_os = "cygwin"))]
     pub fn blocks_free(&self) -> libc::c_long {
         self.0.f_bfree
     }
@@ -560,7 +566,7 @@ impl Statfs {
     }
 
     /// Free blocks available to unprivileged user
-    #[cfg(target_os = "dragonfly")]
+    #[cfg(any(target_os = "dragonfly", target_os = "cygwin"))]
     pub fn blocks_available(&self) -> libc::c_long {
         self.0.f_bavail
     }
@@ -590,7 +596,7 @@ impl Statfs {
     }
 
     /// Total file nodes in filesystem
-    #[cfg(target_os = "dragonfly")]
+    #[cfg(any(target_os = "dragonfly", target_os = "cygwin"))]
     pub fn files(&self) -> libc::c_long {
         self.0.f_files
     }
@@ -613,7 +619,7 @@ impl Statfs {
     }
 
     /// Free file nodes in filesystem
-    #[cfg(target_os = "dragonfly")]
+    #[cfg(any(target_os = "dragonfly", target_os = "cygwin"))]
     pub fn files_free(&self) -> libc::c_long {
         self.0.f_ffree
     }
@@ -639,6 +645,7 @@ impl Statfs {
 impl Debug for Statfs {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         let mut ds = f.debug_struct("Statfs");
+        #[cfg(not(target_os = "cygwin"))]
         ds.field("optimal_transfer_size", &self.optimal_transfer_size());
         ds.field("block_size", &self.block_size());
         ds.field("blocks", &self.blocks());

From 821d7c9771c5835f45f70fee6fdcf2f7b3a3b5e4 Mon Sep 17 00:00:00 2001
From: Berrysoft <Strawberry_Str@hotmail.com>
Date: Wed, 12 Mar 2025 14:34:50 +0800
Subject: [PATCH 07/14] fix: some tests for cygwin

---
 src/sys/socket/addr.rs    | 10 +++++++---
 test/sys/mod.rs           |  3 ++-
 test/sys/test_pthread.rs  | 10 ++++++++--
 test/sys/test_resource.rs |  1 +
 test/sys/test_socket.rs   |  3 ++-
 test/sys/test_uio.rs      |  6 ++++--
 test/test_unistd.rs       |  3 ++-
 7 files changed, 26 insertions(+), 10 deletions(-)

diff --git a/src/sys/socket/addr.rs b/src/sys/socket/addr.rs
index fdaff3660b..bb6c54fd21 100644
--- a/src/sys/socket/addr.rs
+++ b/src/sys/socket/addr.rs
@@ -530,7 +530,8 @@ impl SockaddrLike for UnixAddr {
         linux_android,
         target_os = "fuchsia",
         solarish,
-        target_os = "redox"
+        target_os = "redox",
+        target_os = "cygwin",
     ))]
     fn len(&self) -> libc::socklen_t {
         self.sun_len.into()
@@ -1171,6 +1172,7 @@ impl SockaddrLike for SockaddrStorage {
                     linux_android,
                     target_os = "fuchsia",
                     solarish,
+                    target_os = "cygwin",
                 ))]
                 if i32::from(ss.ss_family) == libc::AF_UNIX {
                     // Safe because we UnixAddr is strictly smaller than
@@ -1227,7 +1229,7 @@ impl SockaddrLike for SockaddrStorage {
         }
     }
 
-    #[cfg(any(linux_android, target_os = "fuchsia", solarish))]
+    #[cfg(any(linux_android, target_os = "fuchsia", solarish, target_os = "cygwin"))]
     fn len(&self) -> libc::socklen_t {
         match self.as_unix_addr() {
             // The UnixAddr type knows its own length
@@ -1289,6 +1291,7 @@ impl SockaddrStorage {
             if #[cfg(any(linux_android,
                      target_os = "fuchsia",
                      solarish,
+                     target_os = "cygwin",
                 ))]
             {
                 let p = unsafe{ &self.ss as *const libc::sockaddr_storage };
@@ -1318,6 +1321,7 @@ impl SockaddrStorage {
             if #[cfg(any(linux_android,
                      target_os = "fuchsia",
                      solarish,
+                     target_os = "cygwin",
                 ))]
             {
                 let p = unsafe{ &self.ss as *const libc::sockaddr_storage };
@@ -2193,7 +2197,7 @@ mod tests {
         }
     }
 
-    #[cfg(not(any(target_os = "hurd", target_os = "redox")))]
+    #[cfg(not(any(target_os = "hurd", target_os = "redox", target_os = "cygwin")))]
     #[allow(clippy::cast_ptr_alignment)]
     mod link {
         #[cfg(any(apple_targets, solarish))]
diff --git a/test/sys/mod.rs b/test/sys/mod.rs
index 63b256298e..ab7c5167ce 100644
--- a/test/sys/mod.rs
+++ b/test/sys/mod.rs
@@ -19,7 +19,8 @@ mod test_aio;
     target_os = "redox",
     target_os = "fuchsia",
     target_os = "haiku",
-    target_os = "hurd"
+    target_os = "hurd",
+    target_os = "cygwin"
 )))]
 mod test_ioctl;
 #[cfg(not(target_os = "redox"))]
diff --git a/test/sys/test_pthread.rs b/test/sys/test_pthread.rs
index 5af128ce63..0403ffad31 100644
--- a/test/sys/test_pthread.rs
+++ b/test/sys/test_pthread.rs
@@ -1,6 +1,11 @@
 use nix::sys::pthread::*;
 
-#[cfg(any(target_env = "musl", target_os = "redox", target_env = "ohos"))]
+#[cfg(any(
+    target_env = "musl",
+    target_os = "redox",
+    target_env = "ohos",
+    target_os = "cygwin"
+))]
 #[test]
 fn test_pthread_self() {
     let tid = pthread_self();
@@ -10,7 +15,8 @@ fn test_pthread_self() {
 #[cfg(not(any(
     target_env = "musl",
     target_os = "redox",
-    target_env = "ohos"
+    target_env = "ohos",
+    target_os = "cygwin"
 )))]
 #[test]
 fn test_pthread_self() {
diff --git a/test/sys/test_resource.rs b/test/sys/test_resource.rs
index 8b12a9495b..102b1b57d8 100644
--- a/test/sys/test_resource.rs
+++ b/test/sys/test_resource.rs
@@ -10,6 +10,7 @@ use nix::sys::resource::{getrusage, UsageWho};
 /// to put the new soft limit in effect, and then getrlimit() once more to ensure the limits have
 /// been updated.
 #[test]
+#[cfg_attr(target_os = "cygwin", ignore)]
 pub fn test_resource_limits_nofile() {
     let (mut soft_limit, hard_limit) =
         getrlimit(Resource::RLIMIT_NOFILE).unwrap();
diff --git a/test/sys/test_socket.rs b/test/sys/test_socket.rs
index 5a43aab437..5f1a8cdff3 100644
--- a/test/sys/test_socket.rs
+++ b/test/sys/test_socket.rs
@@ -1707,6 +1707,7 @@ pub fn test_listen_maxbacklog() {
 pub fn test_listen_wrongbacklog() {
     use nix::sys::socket::Backlog;
 
+    #[cfg(not(target_os = "cygwin"))]
     assert!(Backlog::new(libc::SOMAXCONN + 1).is_err());
     assert!(Backlog::new(-2).is_err());
 }
@@ -3152,7 +3153,7 @@ fn can_use_cmsg_space() {
     let _ = cmsg_space!(u8);
 }
 
-#[cfg(not(any(linux_android, target_os = "redox", target_os = "haiku")))]
+#[cfg(not(any(linux_android, target_os = "redox", target_os = "haiku", target_os = "cygwin")))]
 #[test]
 fn can_open_routing_socket() {
     use nix::sys::socket::{socket, AddressFamily, SockFlag, SockType};
diff --git a/test/sys/test_uio.rs b/test/sys/test_uio.rs
index 22248db141..43f2f7a01e 100644
--- a/test/sys/test_uio.rs
+++ b/test/sys/test_uio.rs
@@ -144,7 +144,8 @@ fn test_pread() {
 #[cfg(not(any(
     target_os = "redox",
     target_os = "haiku",
-    target_os = "solaris"
+    target_os = "solaris",
+    target_os = "cygwin"
 )))]
 fn test_pwritev() {
     use std::io::Read;
@@ -183,7 +184,8 @@ fn test_pwritev() {
 #[cfg(not(any(
     target_os = "redox",
     target_os = "haiku",
-    target_os = "solaris"
+    target_os = "solaris",
+    target_os = "cygwin"
 )))]
 fn test_preadv() {
     use std::io::Write;
diff --git a/test/test_unistd.rs b/test/test_unistd.rs
index 19b9f94284..2c54c4757c 100644
--- a/test/test_unistd.rs
+++ b/test/test_unistd.rs
@@ -631,7 +631,8 @@ cfg_if! {
 #[cfg(not(any(
     target_os = "redox",
     target_os = "fuchsia",
-    target_os = "haiku"
+    target_os = "haiku",
+    target_os = "cygwin"
 )))]
 fn test_acct() {
     use std::process::Command;

From 70781c63465adfe4f4b9dfaaa65ecf21fb94e51a Mon Sep 17 00:00:00 2001
From: Berrysoft <Strawberry_Str@hotmail.com>
Date: Thu, 13 Mar 2025 16:22:44 +0800
Subject: [PATCH 08/14] fix: ignore failed tests on cygwin

---
 test/sys/test_socket.rs  | 3 +++
 test/sys/test_sockopt.rs | 1 +
 test/sys/test_stat.rs    | 5 +++++
 test/test_fcntl.rs       | 1 +
 test/test_net.rs         | 2 ++
 test/test_unistd.rs      | 4 ++++
 6 files changed, 16 insertions(+)

diff --git a/test/sys/test_socket.rs b/test/sys/test_socket.rs
index 5f1a8cdff3..a8b966fd64 100644
--- a/test/sys/test_socket.rs
+++ b/test/sys/test_socket.rs
@@ -327,6 +327,7 @@ pub fn test_socketpair() {
 }
 
 #[test]
+#[cfg_attr(target_os = "cygwin", ignore)]
 pub fn test_recvmsg_sockaddr_un() {
     use nix::sys::socket::{
         self, bind, socket, AddressFamily, MsgFlags, SockFlag, SockType,
@@ -841,6 +842,7 @@ pub fn test_recvmsg_ebadf() {
 // 2.12.0.  https://bugs.launchpad.net/qemu/+bug/1701808
 #[cfg_attr(qemu, ignore)]
 #[test]
+#[cfg_attr(target_os = "cygwin", ignore)]
 pub fn test_scm_rights() {
     use nix::sys::socket::{
         recvmsg, sendmsg, socketpair, AddressFamily, ControlMessage,
@@ -1327,6 +1329,7 @@ pub fn test_sendmsg_ipv4sendsrcaddr() {
 // 2.12.0.  https://bugs.launchpad.net/qemu/+bug/1701808
 #[cfg_attr(qemu, ignore)]
 #[test]
+#[cfg_attr(target_os = "cygwin", ignore)]
 fn test_scm_rights_single_cmsg_multiple_fds() {
     use nix::sys::socket::{
         recvmsg, sendmsg, ControlMessage, ControlMessageOwned, MsgFlags,
diff --git a/test/sys/test_sockopt.rs b/test/sys/test_sockopt.rs
index 42697ffa24..1a5e1cdac6 100644
--- a/test/sys/test_sockopt.rs
+++ b/test/sys/test_sockopt.rs
@@ -159,6 +159,7 @@ fn test_so_listen_q_limit() {
 }
 
 #[test]
+#[cfg_attr(target_os = "cygwin", ignore)]
 fn test_so_tcp_maxseg() {
     use nix::sys::socket::{
         accept, bind, connect, getsockname, listen, Backlog, SockaddrIn,
diff --git a/test/sys/test_stat.rs b/test/sys/test_stat.rs
index fed517cf76..8d3adf7928 100644
--- a/test/sys/test_stat.rs
+++ b/test/sys/test_stat.rs
@@ -145,6 +145,7 @@ fn test_stat_fstat_lstat() {
 }
 
 #[test]
+#[cfg_attr(target_os = "cygwin", ignore)]
 fn test_fchmod() {
     let tempdir = tempfile::tempdir().unwrap();
     let filename = tempdir.path().join("foo.txt");
@@ -168,6 +169,7 @@ fn test_fchmod() {
 
 #[test]
 #[cfg(not(target_os = "redox"))]
+#[cfg_attr(target_os = "cygwin", ignore)]
 fn test_fchmodat() {
     let _dr = crate::DirRestore::new();
     let tempdir = tempfile::tempdir().unwrap();
@@ -331,6 +333,7 @@ fn test_mkdirat_success_path() {
 
 #[test]
 #[cfg(not(any(target_os = "redox", target_os = "haiku")))]
+#[cfg_attr(target_os = "cygwin", ignore)]
 fn test_mkdirat_success_mode() {
     let expected_bits =
         stat::SFlag::S_IFDIR.bits() | stat::Mode::S_IRWXU.bits();
@@ -371,6 +374,7 @@ fn test_mkdirat_fail() {
     target_os = "redox",
     target_os = "solaris"
 )))]
+#[cfg_attr(target_os = "cygwin", ignore)]
 fn test_mknod() {
     use stat::{lstat, mknod, SFlag};
 
@@ -391,6 +395,7 @@ fn test_mknod() {
     target_os = "haiku",
     target_os = "redox"
 )))]
+#[cfg_attr(target_os = "cygwin", ignore)]
 fn test_mknodat() {
     use fcntl::{AtFlags, OFlag};
     use nix::dir::Dir;
diff --git a/test/test_fcntl.rs b/test/test_fcntl.rs
index 76c3b9f2dc..bbbcb604e5 100644
--- a/test/test_fcntl.rs
+++ b/test/test_fcntl.rs
@@ -243,6 +243,7 @@ fn test_renameat2_noreplace() {
 
 #[test]
 #[cfg(not(target_os = "redox"))]
+#[cfg_attr(target_os = "cygwin", ignore)]
 fn test_readlink() {
     let tempdir = tempfile::tempdir().unwrap();
     let src = tempdir.path().join("a");
diff --git a/test/test_net.rs b/test/test_net.rs
index 46a3efd501..be86b65d30 100644
--- a/test/test_net.rs
+++ b/test/test_net.rs
@@ -10,11 +10,13 @@ const LOOPBACK: &[u8] = b"lo0";
 const LOOPBACK: &[u8] = b"loop";
 
 #[test]
+#[cfg_attr(target_os = "cygwin", ignore)]
 fn test_if_nametoindex() {
     if_nametoindex(LOOPBACK).expect("assertion failed");
 }
 
 #[test]
+#[cfg_attr(target_os = "cygwin", ignore)]
 fn test_if_indextoname() {
     let loopback_index = if_nametoindex(LOOPBACK).expect("assertion failed");
     assert_eq!(
diff --git a/test/test_unistd.rs b/test/test_unistd.rs
index 2c54c4757c..681368e113 100644
--- a/test/test_unistd.rs
+++ b/test/test_unistd.rs
@@ -516,6 +516,7 @@ fn test_getcwd() {
 }
 
 #[test]
+#[cfg_attr(target_os = "cygwin", ignore)]
 fn test_chown() {
     // Testing for anything other than our own UID/GID is hard.
     let uid = Some(getuid());
@@ -550,6 +551,7 @@ fn test_fchown() {
 
 #[test]
 #[cfg(not(target_os = "redox"))]
+#[cfg_attr(target_os = "cygwin", ignore)]
 fn test_fchownat() {
     use nix::fcntl::AtFlags;
     use nix::fcntl::AT_FDCWD;
@@ -868,6 +870,7 @@ fn test_canceling_alarm() {
 
 #[test]
 #[cfg(not(any(target_os = "redox", target_os = "haiku")))]
+#[cfg_attr(target_os = "cygwin", ignore)]
 fn test_symlinkat() {
     use nix::fcntl::AT_FDCWD;
 
@@ -1221,6 +1224,7 @@ fn test_access_file_exists() {
 }
 
 #[cfg(not(target_os = "redox"))]
+#[cfg_attr(target_os = "cygwin", ignore)]
 #[test]
 fn test_user_into_passwd() {
     // get the UID of the "nobody" user

From 83f0e89b1e75a782bc204da4a9c5ac8022b79e90 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E7=8E=8B=E5=AE=87=E9=80=B8?= <Strawberry_Str@hotmail.com>
Date: Tue, 18 Mar 2025 15:05:41 +0800
Subject: [PATCH 09/14] Fix deprecated warnings

---
 test/sys/test_sockopt.rs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/test/sys/test_sockopt.rs b/test/sys/test_sockopt.rs
index 1a5e1cdac6..a367aa0aba 100644
--- a/test/sys/test_sockopt.rs
+++ b/test/sys/test_sockopt.rs
@@ -242,6 +242,7 @@ fn test_so_type_unknown() {
     use nix::errno::Errno;
 
     require_capability!("test_so_type", CAP_NET_RAW);
+    #[allow(deprecated)]
     let raw_fd = unsafe { libc::socket(libc::AF_PACKET, libc::SOCK_PACKET, 0) };
     assert!(raw_fd >= 0, "Error opening socket: {}", nix::Error::last());
     let sockfd = unsafe { OwnedFd::from_raw_fd(raw_fd) };

From 99b87bd7075c37218430f2786d901a6bfdc925b6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E7=8E=8B=E5=AE=87=E9=80=B8?= <Strawberry_Str@hotmail.com>
Date: Tue, 18 Mar 2025 15:06:46 +0800
Subject: [PATCH 10/14] Format code

---
 src/sys/mod.rs          | 8 +++++++-
 test/sys/test_socket.rs | 7 ++++++-
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/sys/mod.rs b/src/sys/mod.rs
index 95ad68b4ad..17b033170d 100644
--- a/src/sys/mod.rs
+++ b/src/sys/mod.rs
@@ -137,7 +137,13 @@ feature! {
     pub mod stat;
 }
 
-#[cfg(any(linux_android, freebsdlike, apple_targets, target_os = "openbsd", target_os = "cygwin"))]
+#[cfg(any(
+    linux_android,
+    freebsdlike,
+    apple_targets,
+    target_os = "openbsd",
+    target_os = "cygwin"
+))]
 feature! {
     #![feature = "fs"]
     pub mod statfs;
diff --git a/test/sys/test_socket.rs b/test/sys/test_socket.rs
index a8b966fd64..95598f470c 100644
--- a/test/sys/test_socket.rs
+++ b/test/sys/test_socket.rs
@@ -3156,7 +3156,12 @@ fn can_use_cmsg_space() {
     let _ = cmsg_space!(u8);
 }
 
-#[cfg(not(any(linux_android, target_os = "redox", target_os = "haiku", target_os = "cygwin")))]
+#[cfg(not(any(
+    linux_android,
+    target_os = "redox",
+    target_os = "haiku",
+    target_os = "cygwin"
+)))]
 #[test]
 fn can_open_routing_socket() {
     use nix::sys::socket::{socket, AddressFamily, SockFlag, SockType};

From c6fe2f28f58e9908dbbc40895a830ac9b4276815 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E7=8E=8B=E5=AE=87=E9=80=B8?= <Strawberry_Str@hotmail.com>
Date: Fri, 21 Mar 2025 12:11:28 +0800
Subject: [PATCH 11/14] fix: mark from_i32 pub(crate)

---
 src/errno.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/errno.rs b/src/errno.rs
index d7d3926d30..497e33dbbf 100644
--- a/src/errno.rs
+++ b/src/errno.rs
@@ -3727,7 +3727,7 @@ mod consts {
         pub const EOPNOTSUPP: Errno = Errno::ENOTSUP;
     }
 
-    pub const fn from_i32(e: i32) -> Errno {
+    pub(crate) const fn from_i32(e: i32) -> Errno {
         use self::Errno::*;
 
         match e {

From 609242e876f2ccd1882395076b6a881de1d83c57 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E7=8E=8B=E5=AE=87=E9=80=B8?= <Strawberry_Str@hotmail.com>
Date: Fri, 21 Mar 2025 18:50:26 +0800
Subject: [PATCH 12/14] test: restore symlink tests on cygwin

---
 test/test_fcntl.rs  | 1 -
 test/test_unistd.rs | 1 -
 2 files changed, 2 deletions(-)

diff --git a/test/test_fcntl.rs b/test/test_fcntl.rs
index bbbcb604e5..76c3b9f2dc 100644
--- a/test/test_fcntl.rs
+++ b/test/test_fcntl.rs
@@ -243,7 +243,6 @@ fn test_renameat2_noreplace() {
 
 #[test]
 #[cfg(not(target_os = "redox"))]
-#[cfg_attr(target_os = "cygwin", ignore)]
 fn test_readlink() {
     let tempdir = tempfile::tempdir().unwrap();
     let src = tempdir.path().join("a");
diff --git a/test/test_unistd.rs b/test/test_unistd.rs
index 681368e113..12e7f3bfda 100644
--- a/test/test_unistd.rs
+++ b/test/test_unistd.rs
@@ -870,7 +870,6 @@ fn test_canceling_alarm() {
 
 #[test]
 #[cfg(not(any(target_os = "redox", target_os = "haiku")))]
-#[cfg_attr(target_os = "cygwin", ignore)]
 fn test_symlinkat() {
     use nix::fcntl::AT_FDCWD;
 

From 895e2c285edf7c048b5db290fa01b9b927681295 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E7=8E=8B=E5=AE=87=E9=80=B8?= <Strawberry_Str@hotmail.com>
Date: Fri, 21 Mar 2025 19:23:46 +0800
Subject: [PATCH 13/14] test: test user passwd on cygwin

---
 test/test_unistd.rs | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/test/test_unistd.rs b/test/test_unistd.rs
index 12e7f3bfda..a6aa761dc9 100644
--- a/test/test_unistd.rs
+++ b/test/test_unistd.rs
@@ -1223,15 +1223,18 @@ fn test_access_file_exists() {
 }
 
 #[cfg(not(target_os = "redox"))]
-#[cfg_attr(target_os = "cygwin", ignore)]
 #[test]
 fn test_user_into_passwd() {
-    // get the UID of the "nobody" user
-    #[cfg(not(target_os = "haiku"))]
-    let test_username = "nobody";
-    // "nobody" unavailable on haiku
-    #[cfg(target_os = "haiku")]
-    let test_username = "user";
+    let test_username = if cfg!(target_os = "haiku") {
+        // "nobody" unavailable on haiku
+        "user"
+    } else if cfg!(target_os = "cygwin") {
+        // the Windows admin user
+        "Administrator"
+    } else {
+        // get the UID of the "nobody" user
+        "nobody"
+    };
 
     let nobody = User::from_name(test_username).unwrap().unwrap();
     let pwd: libc::passwd = nobody.into();

From 8baede52779112733c48d09067172b237683fb01 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E7=8E=8B=E5=AE=87=E9=80=B8?= <Strawberry_Str@hotmail.com>
Date: Sat, 22 Mar 2025 16:51:51 +0800
Subject: [PATCH 14/14] test: restore more tests on cygwin

They pass on Cygwin, but not on MSYS2 as intended.
---
 test/sys/test_stat.rs | 5 -----
 test/test_unistd.rs   | 2 --
 2 files changed, 7 deletions(-)

diff --git a/test/sys/test_stat.rs b/test/sys/test_stat.rs
index 8d3adf7928..fed517cf76 100644
--- a/test/sys/test_stat.rs
+++ b/test/sys/test_stat.rs
@@ -145,7 +145,6 @@ fn test_stat_fstat_lstat() {
 }
 
 #[test]
-#[cfg_attr(target_os = "cygwin", ignore)]
 fn test_fchmod() {
     let tempdir = tempfile::tempdir().unwrap();
     let filename = tempdir.path().join("foo.txt");
@@ -169,7 +168,6 @@ fn test_fchmod() {
 
 #[test]
 #[cfg(not(target_os = "redox"))]
-#[cfg_attr(target_os = "cygwin", ignore)]
 fn test_fchmodat() {
     let _dr = crate::DirRestore::new();
     let tempdir = tempfile::tempdir().unwrap();
@@ -333,7 +331,6 @@ fn test_mkdirat_success_path() {
 
 #[test]
 #[cfg(not(any(target_os = "redox", target_os = "haiku")))]
-#[cfg_attr(target_os = "cygwin", ignore)]
 fn test_mkdirat_success_mode() {
     let expected_bits =
         stat::SFlag::S_IFDIR.bits() | stat::Mode::S_IRWXU.bits();
@@ -374,7 +371,6 @@ fn test_mkdirat_fail() {
     target_os = "redox",
     target_os = "solaris"
 )))]
-#[cfg_attr(target_os = "cygwin", ignore)]
 fn test_mknod() {
     use stat::{lstat, mknod, SFlag};
 
@@ -395,7 +391,6 @@ fn test_mknod() {
     target_os = "haiku",
     target_os = "redox"
 )))]
-#[cfg_attr(target_os = "cygwin", ignore)]
 fn test_mknodat() {
     use fcntl::{AtFlags, OFlag};
     use nix::dir::Dir;
diff --git a/test/test_unistd.rs b/test/test_unistd.rs
index a6aa761dc9..6037bb7a02 100644
--- a/test/test_unistd.rs
+++ b/test/test_unistd.rs
@@ -516,7 +516,6 @@ fn test_getcwd() {
 }
 
 #[test]
-#[cfg_attr(target_os = "cygwin", ignore)]
 fn test_chown() {
     // Testing for anything other than our own UID/GID is hard.
     let uid = Some(getuid());
@@ -551,7 +550,6 @@ fn test_fchown() {
 
 #[test]
 #[cfg(not(target_os = "redox"))]
-#[cfg_attr(target_os = "cygwin", ignore)]
 fn test_fchownat() {
     use nix::fcntl::AtFlags;
     use nix::fcntl::AT_FDCWD;