library/std/src/sys/unix/mod.rs

   1 #![allow(missing_docs, nonstandard_style)]
   2
   3 use crate::io::ErrorKind;
   4
   5 pub use self::rand::hashmap_random_keys;
   6 pub use libc::strlen;
   7
   8 #[cfg(not(target_os = "espidf"))]
   9 #[macro_use]
  10 pub mod weak;
  11
  12 pub mod alloc;
  13 pub mod android;
  14 pub mod args;
  15 #[path = "../unix/cmath.rs"]
  16 pub mod cmath;
  17 pub mod condvar;
  18 pub mod env;
  19 pub mod fd;
  20 pub mod fs;
  21 pub mod futex;
  22 pub mod io;
  23 #[cfg(any(target_os = "linux", target_os = "android"))]
  24 pub mod kernel_copy;
  25 #[cfg(target_os = "l4re")]
  26 mod l4re;
  27 pub mod memchr;
  28 pub mod mutex;
  29 #[cfg(not(target_os = "l4re"))]
  30 pub mod net;
  31 #[cfg(target_os = "l4re")]
  32 pub use self::l4re::net;
  33 pub mod os;
  34 pub mod os_str;
  35 pub mod path;
  36 pub mod pipe;
  37 pub mod process;
  38 pub mod rand;
  39 pub mod rwlock;
  40 pub mod stack_overflow;
  41 pub mod stdio;
  42 pub mod thread;
  43 pub mod thread_local_dtor;
  44 pub mod thread_local_key;
  45 pub mod time;
  46
  47 #[cfg(target_os = "espidf")]
  48 pub fn init(argc: isize, argv: *const *const u8) {}
  49
  50 #[cfg(not(target_os = "espidf"))]
  51 // SAFETY: must be called only once during runtime initialization.
  52 // NOTE: this is not guaranteed to run, for example when Rust code is called externally.
  53 pub unsafe fn init(argc: isize, argv: *const *const u8) {
  54     // The standard streams might be closed on application startup. To prevent
  55     // std::io::{stdin, stdout,stderr} objects from using other unrelated file
  56     // resources opened later, we reopen standards streams when they are closed.
  57     sanitize_standard_fds();
  58
  59     // By default, some platforms will send a *signal* when an EPIPE error
  60     // would otherwise be delivered. This runtime doesn't install a SIGPIPE
  61     // handler, causing it to kill the program, which isn't exactly what we
  62     // want!
  63     //
  64     // Hence, we set SIGPIPE to ignore when the program starts up in order
  65     // to prevent this problem.
  66     reset_sigpipe();
  67
  68     stack_overflow::init();
  69     args::init(argc, argv);
  70
  71     unsafe fn sanitize_standard_fds() {
  72         #[cfg(not(miri))]
  73         // The standard fds are always available in Miri.
  74         cfg_if::cfg_if! {
  75             if #[cfg(not(any(
  76                 target_os = "emscripten",
  77                 target_os = "fuchsia",
  78                 target_os = "vxworks",
  79                 // The poll on Darwin doesn't set POLLNVAL for closed fds.
  80                 target_os = "macos",
  81                 target_os = "ios",
  82                 target_os = "redox",
  83             )))] {
  84                 use crate::sys::os::errno;
  85                 let pfds: &mut [_] = &mut [
  86                     libc::pollfd { fd: 0, events: 0, revents: 0 },
  87                     libc::pollfd { fd: 1, events: 0, revents: 0 },
  88                     libc::pollfd { fd: 2, events: 0, revents: 0 },
  89                 ];
  90                 while libc::poll(pfds.as_mut_ptr(), 3, 0) == -1 {
  91                     if errno() == libc::EINTR {
  92                         continue;
  93                     }
  94                     libc::abort();
  95                 }
  96                 for pfd in pfds {
  97                     if pfd.revents & libc::POLLNVAL == 0 {
  98                         continue;
  99                     }
 100                     if libc::open("/dev/null\0".as_ptr().cast(), libc::O_RDWR, 0) == -1 {
 101                         // If the stream is closed but we failed to reopen it, abort the
 102                         // process. Otherwise we wouldn't preserve the safety of
 103                         // operations on the corresponding Rust object Stdin, Stdout, or
 104                         // Stderr.
 105                         libc::abort();
 106                     }
 107                 }
 108             } else if #[cfg(any(target_os = "macos", target_os = "ios", target_os = "redox"))] {
 109                 use crate::sys::os::errno;
 110                 for fd in 0..3 {
 111                     if libc::fcntl(fd, libc::F_GETFD) == -1 && errno() == libc::EBADF {
 112                         if libc::open("/dev/null\0".as_ptr().cast(), libc::O_RDWR, 0) == -1 {
 113                             libc::abort();
 114                         }
 115                     }
 116                 }
 117             }
 118         }
 119     }
 120
 121     unsafe fn reset_sigpipe() {
 122         #[cfg(not(any(target_os = "emscripten", target_os = "fuchsia")))]
 123         rtassert!(signal(libc::SIGPIPE, libc::SIG_IGN) != libc::SIG_ERR);
 124     }
 125 }
 126
 127 // SAFETY: must be called only once during runtime cleanup.
 128 // NOTE: this is not guaranteed to run, for example when the program aborts.
 129 pub unsafe fn cleanup() {
 130     stack_overflow::cleanup();
 131 }
 132
 133 #[cfg(target_os = "android")]
 134 pub use crate::sys::android::signal;
 135 #[cfg(not(target_os = "android"))]
 136 pub use libc::signal;
 137
 138 pub fn decode_error_kind(errno: i32) -> ErrorKind {
 139     use ErrorKind::*;
 140     match errno as libc::c_int {
 141         libc::E2BIG => ArgumentListTooLong,
 142         libc::EADDRINUSE => AddrInUse,
 143         libc::EADDRNOTAVAIL => AddrNotAvailable,
 144         libc::EBUSY => ResourceBusy,
 145         libc::ECONNABORTED => ConnectionAborted,
 146         libc::ECONNREFUSED => ConnectionRefused,
 147         libc::ECONNRESET => ConnectionReset,
 148         libc::EDEADLK => Deadlock,
 149         libc::EDQUOT => FilesystemQuotaExceeded,
 150         libc::EEXIST => AlreadyExists,
 151         libc::EFBIG => FileTooLarge,
 152         libc::EHOSTUNREACH => HostUnreachable,
 153         libc::EINTR => Interrupted,
 154         libc::EINVAL => InvalidInput,
 155         libc::EISDIR => IsADirectory,
 156         libc::ELOOP => FilesystemLoop,
 157         libc::ENOENT => NotFound,
 158         libc::ENOMEM => OutOfMemory,
 159         libc::ENOSPC => StorageFull,
 160         libc::ENOSYS => Unsupported,
 161         libc::EMLINK => TooManyLinks,
 162         libc::ENAMETOOLONG => FilenameTooLong,
 163         libc::ENETDOWN => NetworkDown,
 164         libc::ENETUNREACH => NetworkUnreachable,
 165         libc::ENOTCONN => NotConnected,
 166         libc::ENOTDIR => NotADirectory,
 167         libc::ENOTEMPTY => DirectoryNotEmpty,
 168         libc::EPIPE => BrokenPipe,
 169         libc::EROFS => ReadOnlyFilesystem,
 170         libc::ESPIPE => NotSeekable,
 171         libc::ESTALE => StaleNetworkFileHandle,
 172         libc::ETIMEDOUT => TimedOut,
 173         libc::ETXTBSY => ExecutableFileBusy,
 174         libc::EXDEV => CrossesDevices,
 175
 176         libc::EACCES | libc::EPERM => PermissionDenied,
 177
 178         // These two constants can have the same value on some systems,
 179         // but different values on others, so we can't use a match
 180         // clause
 181         x if x == libc::EAGAIN || x == libc::EWOULDBLOCK => WouldBlock,
 182
 183         _ => Uncategorized,
 184     }
 185 }
 186
 187 #[doc(hidden)]
 188 pub trait IsMinusOne {
 189     fn is_minus_one(&self) -> bool;
 190 }
 191
 192 macro_rules! impl_is_minus_one {
 193     ($($t:ident)*) => ($(impl IsMinusOne for $t {
 194         fn is_minus_one(&self) -> bool {
 195             *self == -1
 196         }
 197     })*)
 198 }
 199
 200 impl_is_minus_one! { i8 i16 i32 i64 isize }
 201
 202 pub fn cvt<T: IsMinusOne>(t: T) -> crate::io::Result<T> {
 203     if t.is_minus_one() { Err(crate::io::Error::last_os_error()) } else { Ok(t) }
 204 }
 205
 206 pub fn cvt_r<T, F>(mut f: F) -> crate::io::Result<T>
 207 where
 208     T: IsMinusOne,
 209     F: FnMut() -> T,
 210 {
 211     loop {
 212         match cvt(f()) {
 213             Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
 214             other => return other,
 215         }
 216     }
 217 }
 218
 219 pub fn cvt_nz(error: libc::c_int) -> crate::io::Result<()> {
 220     if error == 0 { Ok(()) } else { Err(crate::io::Error::from_raw_os_error(error)) }
 221 }
 222
 223 // libc::abort() will run the SIGABRT handler.  That's fine because anyone who
 224 // installs a SIGABRT handler already has to expect it to run in Very Bad
 225 // situations (eg, malloc crashing).
 226 //
 227 // Current glibc's abort() function unblocks SIGABRT, raises SIGABRT, clears the
 228 // SIGABRT handler and raises it again, and then starts to get creative.
 229 //
 230 // See the public documentation for `intrinsics::abort()` and `process::abort()`
 231 // for further discussion.
 232 //
 233 // There is confusion about whether libc::abort() flushes stdio streams.
 234 // libc::abort() is required by ISO C 99 (7.14.1.1p5) to be async-signal-safe,
 235 // so flushing streams is at least extremely hard, if not entirely impossible.
 236 //
 237 // However, some versions of POSIX (eg IEEE Std 1003.1-2001) required abort to
 238 // do so.  In 1003.1-2004 this was fixed.
 239 //
 240 // glibc's implementation did the flush, unsafely, before glibc commit
 241 // 91e7cf982d01 `abort: Do not flush stdio streams [BZ #15436]' by Florian
 242 // Weimer.  According to glibc's NEWS:
 243 //
 244 //    The abort function terminates the process immediately, without flushing
 245 //    stdio streams.  Previous glibc versions used to flush streams, resulting
 246 //    in deadlocks and further data corruption.  This change also affects
 247 //    process aborts as the result of assertion failures.
 248 //
 249 // This is an accurate description of the problem.  The only solution for
 250 // program with nontrivial use of C stdio is a fixed libc - one which does not
 251 // try to flush in abort - since even libc-internal errors, and assertion
 252 // failures generated from C, will go via abort().
 253 //
 254 // On systems with old, buggy, libcs, the impact can be severe for a
 255 // multithreaded C program.  It is much less severe for Rust, because Rust
 256 // stdlib doesn't use libc stdio buffering.  In a typical Rust program, which
 257 // does not use C stdio, even a buggy libc::abort() is, in fact, safe.
 258 pub fn abort_internal() -> ! {
 259     unsafe { libc::abort() }
 260 }
 261
 262 cfg_if::cfg_if! {
 263     if #[cfg(target_os = "android")] {
 264         #[link(name = "dl")]
 265         #[link(name = "log")]
 266         extern "C" {}
 267     } else if #[cfg(target_os = "freebsd")] {
 268         #[link(name = "execinfo")]
 269         #[link(name = "pthread")]
 270         extern "C" {}
 271     } else if #[cfg(target_os = "netbsd")] {
 272         #[link(name = "pthread")]
 273         #[link(name = "rt")]
 274         extern "C" {}
 275     } else if #[cfg(any(target_os = "dragonfly", target_os = "openbsd"))] {
 276         #[link(name = "pthread")]
 277         extern "C" {}
 278     } else if #[cfg(target_os = "solaris")] {
 279         #[link(name = "socket")]
 280         #[link(name = "posix4")]
 281         #[link(name = "pthread")]
 282         #[link(name = "resolv")]
 283         extern "C" {}
 284     } else if #[cfg(target_os = "illumos")] {
 285         #[link(name = "socket")]
 286         #[link(name = "posix4")]
 287         #[link(name = "pthread")]
 288         #[link(name = "resolv")]
 289         #[link(name = "nsl")]
 290         // Use libumem for the (malloc-compatible) allocator
 291         #[link(name = "umem")]
 292         extern "C" {}
 293     } else if #[cfg(target_os = "macos")] {
 294         #[link(name = "System")]
 295         // res_init and friends require -lresolv on macOS/iOS.
 296         // See #41582 and https://blog.achernya.com/2013/03/os-x-has-silly-libsystem.html
 297         #[link(name = "resolv")]
 298         extern "C" {}
 299     } else if #[cfg(target_os = "ios")] {
 300         #[link(name = "System")]
 301         #[link(name = "objc")]
 302         #[link(name = "Security", kind = "framework")]
 303         #[link(name = "Foundation", kind = "framework")]
 304         #[link(name = "resolv")]
 305         extern "C" {}
 306     } else if #[cfg(target_os = "fuchsia")] {
 307         #[link(name = "zircon")]
 308         #[link(name = "fdio")]
 309         extern "C" {}
 310     } else if #[cfg(all(target_os = "linux", target_env = "uclibc"))] {
 311         #[link(name = "dl")]
 312         extern "C" {}
 313     }
 314 }
 315
 316 #[cfg(target_os = "espidf")]
 317 mod unsupported {
 318     use crate::io;
 319
 320     pub fn unsupported<T>() -> io::Result<T> {
 321         Err(unsupported_err())
 322     }
 323
 324     pub fn unsupported_err() -> io::Error {
 325         io::Error::new_const(
 326             io::ErrorKind::Unsupported,
 327             &"operation not supported on this platform",
 328         )
 329     }
 330 }