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