rust/library/std/src/sys/pal/unix/mod.rs
2025-04-18 19:17:08 -07:00

433 lines
16 KiB
Rust

#![allow(missing_docs, nonstandard_style)]
use crate::io::ErrorKind;
#[cfg(not(target_os = "espidf"))]
#[macro_use]
pub mod weak;
#[cfg(target_os = "fuchsia")]
pub mod fuchsia;
pub mod futex;
#[cfg(any(target_os = "linux", target_os = "android"))]
pub mod kernel_copy;
#[cfg(target_os = "linux")]
pub mod linux;
pub mod os;
pub mod pipe;
pub mod stack_overflow;
pub mod sync;
pub mod thread;
pub mod thread_parking;
pub mod time;
#[cfg(target_os = "espidf")]
pub fn init(_argc: isize, _argv: *const *const u8, _sigpipe: u8) {}
#[cfg(not(target_os = "espidf"))]
#[cfg_attr(target_os = "vita", allow(unused_variables))]
// SAFETY: must be called only once during runtime initialization.
// NOTE: this is not guaranteed to run, for example when Rust code is called externally.
// See `fn init()` in `library/std/src/rt.rs` for docs on `sigpipe`.
pub unsafe fn init(argc: isize, argv: *const *const u8, sigpipe: u8) {
// The standard streams might be closed on application startup. To prevent
// std::io::{stdin, stdout,stderr} objects from using other unrelated file
// resources opened later, we reopen standards streams when they are closed.
sanitize_standard_fds();
// By default, some platforms will send a *signal* when an EPIPE error
// would otherwise be delivered. This runtime doesn't install a SIGPIPE
// handler, causing it to kill the program, which isn't exactly what we
// want!
//
// Hence, we set SIGPIPE to ignore when the program starts up in order
// to prevent this problem. Use `-Zon-broken-pipe=...` to alter this
// behavior.
reset_sigpipe(sigpipe);
stack_overflow::init();
#[cfg(not(target_os = "vita"))]
crate::sys::args::init(argc, argv);
// Normally, `thread::spawn` will call `Thread::set_name` but since this thread
// already exists, we have to call it ourselves. We only do this on Apple targets
// because some unix-like operating systems such as Linux share process-id and
// thread-id for the main thread and so renaming the main thread will rename the
// process and we only want to enable this on platforms we've tested.
if cfg!(target_vendor = "apple") {
thread::Thread::set_name(&c"main");
}
unsafe fn sanitize_standard_fds() {
// fast path with a single syscall for systems with poll()
#[cfg(not(any(
miri,
target_os = "emscripten",
target_os = "fuchsia",
target_os = "vxworks",
target_os = "redox",
target_os = "l4re",
target_os = "horizon",
target_os = "vita",
target_os = "rtems",
// The poll on Darwin doesn't set POLLNVAL for closed fds.
target_vendor = "apple",
)))]
'poll: {
#[cfg(not(all(target_os = "linux", target_env = "gnu")))]
use libc::open as open64;
#[cfg(all(target_os = "linux", target_env = "gnu"))]
use libc::open64;
use crate::sys::os::errno;
let pfds: &mut [_] = &mut [
libc::pollfd { fd: 0, events: 0, revents: 0 },
libc::pollfd { fd: 1, events: 0, revents: 0 },
libc::pollfd { fd: 2, events: 0, revents: 0 },
];
while libc::poll(pfds.as_mut_ptr(), 3, 0) == -1 {
match errno() {
libc::EINTR => continue,
#[cfg(target_vendor = "unikraft")]
libc::ENOSYS => {
// Not all configurations of Unikraft enable `LIBPOSIX_EVENT`.
break 'poll;
}
libc::EINVAL | libc::EAGAIN | libc::ENOMEM => {
// RLIMIT_NOFILE or temporary allocation failures
// may be preventing use of poll(), fall back to fcntl
break 'poll;
}
_ => libc::abort(),
}
}
for pfd in pfds {
if pfd.revents & libc::POLLNVAL == 0 {
continue;
}
if open64(c"/dev/null".as_ptr(), libc::O_RDWR, 0) == -1 {
// If the stream is closed but we failed to reopen it, abort the
// process. Otherwise we wouldn't preserve the safety of
// operations on the corresponding Rust object Stdin, Stdout, or
// Stderr.
libc::abort();
}
}
return;
}
// fallback in case poll isn't available or limited by RLIMIT_NOFILE
#[cfg(not(any(
// The standard fds are always available in Miri.
miri,
target_os = "emscripten",
target_os = "fuchsia",
target_os = "vxworks",
target_os = "l4re",
target_os = "horizon",
target_os = "vita",
)))]
{
#[cfg(not(all(target_os = "linux", target_env = "gnu")))]
use libc::open as open64;
#[cfg(all(target_os = "linux", target_env = "gnu"))]
use libc::open64;
use crate::sys::os::errno;
for fd in 0..3 {
if libc::fcntl(fd, libc::F_GETFD) == -1 && errno() == libc::EBADF {
if open64(c"/dev/null".as_ptr(), libc::O_RDWR, 0) == -1 {
// If the stream is closed but we failed to reopen it, abort the
// process. Otherwise we wouldn't preserve the safety of
// operations on the corresponding Rust object Stdin, Stdout, or
// Stderr.
libc::abort();
}
}
}
}
}
unsafe fn reset_sigpipe(#[allow(unused_variables)] sigpipe: u8) {
#[cfg(not(any(
target_os = "emscripten",
target_os = "fuchsia",
target_os = "horizon",
target_os = "vxworks",
target_os = "vita",
// Unikraft's `signal` implementation is currently broken:
// https://github.com/unikraft/lib-musl/issues/57
target_vendor = "unikraft",
)))]
{
// We don't want to add this as a public type to std, nor do we
// want to `include!` a file from the compiler (which would break
// Miri and xargo for example), so we choose to duplicate these
// constants from `compiler/rustc_session/src/config/sigpipe.rs`.
// See the other file for docs. NOTE: Make sure to keep them in
// sync!
mod sigpipe {
pub const DEFAULT: u8 = 0;
pub const INHERIT: u8 = 1;
pub const SIG_IGN: u8 = 2;
pub const SIG_DFL: u8 = 3;
}
let (sigpipe_attr_specified, handler) = match sigpipe {
sigpipe::DEFAULT => (false, Some(libc::SIG_IGN)),
sigpipe::INHERIT => (true, None),
sigpipe::SIG_IGN => (true, Some(libc::SIG_IGN)),
sigpipe::SIG_DFL => (true, Some(libc::SIG_DFL)),
_ => unreachable!(),
};
if sigpipe_attr_specified {
ON_BROKEN_PIPE_FLAG_USED.store(true, crate::sync::atomic::Ordering::Relaxed);
}
if let Some(handler) = handler {
rtassert!(signal(libc::SIGPIPE, handler) != libc::SIG_ERR);
#[cfg(target_os = "hurd")]
{
rtassert!(signal(libc::SIGLOST, handler) != libc::SIG_ERR);
}
}
}
}
}
// This is set (up to once) in reset_sigpipe.
#[cfg(not(any(
target_os = "espidf",
target_os = "emscripten",
target_os = "fuchsia",
target_os = "horizon",
target_os = "vxworks",
target_os = "vita",
)))]
static ON_BROKEN_PIPE_FLAG_USED: crate::sync::atomic::AtomicBool =
crate::sync::atomic::AtomicBool::new(false);
#[cfg(not(any(
target_os = "espidf",
target_os = "emscripten",
target_os = "fuchsia",
target_os = "horizon",
target_os = "vxworks",
target_os = "vita",
target_os = "nuttx",
)))]
pub(crate) fn on_broken_pipe_flag_used() -> bool {
ON_BROKEN_PIPE_FLAG_USED.load(crate::sync::atomic::Ordering::Relaxed)
}
// SAFETY: must be called only once during runtime cleanup.
// NOTE: this is not guaranteed to run, for example when the program aborts.
pub unsafe fn cleanup() {
stack_overflow::cleanup();
}
#[allow(unused_imports)]
pub use libc::signal;
#[inline]
pub(crate) fn is_interrupted(errno: i32) -> bool {
errno == libc::EINTR
}
pub fn decode_error_kind(errno: i32) -> ErrorKind {
use ErrorKind::*;
match errno as libc::c_int {
libc::E2BIG => ArgumentListTooLong,
libc::EADDRINUSE => AddrInUse,
libc::EADDRNOTAVAIL => AddrNotAvailable,
libc::EBUSY => ResourceBusy,
libc::ECONNABORTED => ConnectionAborted,
libc::ECONNREFUSED => ConnectionRefused,
libc::ECONNRESET => ConnectionReset,
libc::EDEADLK => Deadlock,
libc::EDQUOT => QuotaExceeded,
libc::EEXIST => AlreadyExists,
libc::EFBIG => FileTooLarge,
libc::EHOSTUNREACH => HostUnreachable,
libc::EINTR => Interrupted,
libc::EINVAL => InvalidInput,
libc::EISDIR => IsADirectory,
libc::ELOOP => FilesystemLoop,
libc::ENOENT => NotFound,
libc::ENOMEM => OutOfMemory,
libc::ENOSPC => StorageFull,
libc::ENOSYS => Unsupported,
libc::EMLINK => TooManyLinks,
libc::ENAMETOOLONG => InvalidFilename,
libc::ENETDOWN => NetworkDown,
libc::ENETUNREACH => NetworkUnreachable,
libc::ENOTCONN => NotConnected,
libc::ENOTDIR => NotADirectory,
#[cfg(not(target_os = "aix"))]
libc::ENOTEMPTY => DirectoryNotEmpty,
libc::EPIPE => BrokenPipe,
libc::EROFS => ReadOnlyFilesystem,
libc::ESPIPE => NotSeekable,
libc::ESTALE => StaleNetworkFileHandle,
libc::ETIMEDOUT => TimedOut,
libc::ETXTBSY => ExecutableFileBusy,
libc::EXDEV => CrossesDevices,
libc::EINPROGRESS => InProgress,
libc::EOPNOTSUPP => Unsupported,
libc::EACCES | libc::EPERM => PermissionDenied,
// These two constants can have the same value on some systems,
// but different values on others, so we can't use a match
// clause
x if x == libc::EAGAIN || x == libc::EWOULDBLOCK => WouldBlock,
_ => Uncategorized,
}
}
#[doc(hidden)]
pub trait IsMinusOne {
fn is_minus_one(&self) -> bool;
}
macro_rules! impl_is_minus_one {
($($t:ident)*) => ($(impl IsMinusOne for $t {
fn is_minus_one(&self) -> bool {
*self == -1
}
})*)
}
impl_is_minus_one! { i8 i16 i32 i64 isize }
/// Converts native return values to Result using the *-1 means error is in `errno`* convention.
/// Non-error values are `Ok`-wrapped.
pub fn cvt<T: IsMinusOne>(t: T) -> crate::io::Result<T> {
if t.is_minus_one() { Err(crate::io::Error::last_os_error()) } else { Ok(t) }
}
/// `-1` → look at `errno` → retry on `EINTR`. Otherwise `Ok()`-wrap the closure return value.
pub fn cvt_r<T, F>(mut f: F) -> crate::io::Result<T>
where
T: IsMinusOne,
F: FnMut() -> T,
{
loop {
match cvt(f()) {
Err(ref e) if e.is_interrupted() => {}
other => return other,
}
}
}
#[allow(dead_code)] // Not used on all platforms.
/// Zero means `Ok()`, all other values are treated as raw OS errors. Does not look at `errno`.
pub fn cvt_nz(error: libc::c_int) -> crate::io::Result<()> {
if error == 0 { Ok(()) } else { Err(crate::io::Error::from_raw_os_error(error)) }
}
// libc::abort() will run the SIGABRT handler. That's fine because anyone who
// installs a SIGABRT handler already has to expect it to run in Very Bad
// situations (eg, malloc crashing).
//
// Current glibc's abort() function unblocks SIGABRT, raises SIGABRT, clears the
// SIGABRT handler and raises it again, and then starts to get creative.
//
// See the public documentation for `intrinsics::abort()` and `process::abort()`
// for further discussion.
//
// There is confusion about whether libc::abort() flushes stdio streams.
// libc::abort() is required by ISO C 99 (7.14.1.1p5) to be async-signal-safe,
// so flushing streams is at least extremely hard, if not entirely impossible.
//
// However, some versions of POSIX (eg IEEE Std 1003.1-2001) required abort to
// do so. In 1003.1-2004 this was fixed.
//
// glibc's implementation did the flush, unsafely, before glibc commit
// 91e7cf982d01 `abort: Do not flush stdio streams [BZ #15436]` by Florian
// Weimer. According to glibc's NEWS:
//
// The abort function terminates the process immediately, without flushing
// stdio streams. Previous glibc versions used to flush streams, resulting
// in deadlocks and further data corruption. This change also affects
// process aborts as the result of assertion failures.
//
// This is an accurate description of the problem. The only solution for
// program with nontrivial use of C stdio is a fixed libc - one which does not
// try to flush in abort - since even libc-internal errors, and assertion
// failures generated from C, will go via abort().
//
// On systems with old, buggy, libcs, the impact can be severe for a
// multithreaded C program. It is much less severe for Rust, because Rust
// stdlib doesn't use libc stdio buffering. In a typical Rust program, which
// does not use C stdio, even a buggy libc::abort() is, in fact, safe.
pub fn abort_internal() -> ! {
unsafe { libc::abort() }
}
cfg_if::cfg_if! {
if #[cfg(target_os = "android")] {
#[link(name = "dl", kind = "static", modifiers = "-bundle",
cfg(target_feature = "crt-static"))]
#[link(name = "dl", cfg(not(target_feature = "crt-static")))]
#[link(name = "log", cfg(not(target_feature = "crt-static")))]
unsafe extern "C" {}
} else if #[cfg(target_os = "freebsd")] {
#[link(name = "execinfo")]
#[link(name = "pthread")]
unsafe extern "C" {}
} else if #[cfg(target_os = "netbsd")] {
#[link(name = "pthread")]
#[link(name = "rt")]
unsafe extern "C" {}
} else if #[cfg(any(target_os = "dragonfly", target_os = "openbsd", target_os = "cygwin"))] {
#[link(name = "pthread")]
unsafe extern "C" {}
} else if #[cfg(target_os = "solaris")] {
#[link(name = "socket")]
#[link(name = "posix4")]
#[link(name = "pthread")]
#[link(name = "resolv")]
unsafe extern "C" {}
} else if #[cfg(target_os = "illumos")] {
#[link(name = "socket")]
#[link(name = "posix4")]
#[link(name = "pthread")]
#[link(name = "resolv")]
#[link(name = "nsl")]
// Use libumem for the (malloc-compatible) allocator
#[link(name = "umem")]
unsafe extern "C" {}
} else if #[cfg(target_vendor = "apple")] {
// Link to `libSystem.dylib`.
//
// Don't get confused by the presence of `System.framework`,
// it is a deprecated wrapper over the dynamic library.
#[link(name = "System")]
unsafe extern "C" {}
} else if #[cfg(target_os = "fuchsia")] {
#[link(name = "zircon")]
#[link(name = "fdio")]
unsafe extern "C" {}
} else if #[cfg(all(target_os = "linux", target_env = "uclibc"))] {
#[link(name = "dl")]
unsafe extern "C" {}
} else if #[cfg(target_os = "vita")] {
#[link(name = "pthread", kind = "static", modifiers = "-bundle")]
unsafe extern "C" {}
}
}
#[cfg(any(target_os = "espidf", target_os = "horizon", target_os = "vita", target_os = "nuttx"))]
pub mod unsupported {
use crate::io;
pub fn unsupported<T>() -> io::Result<T> {
Err(unsupported_err())
}
pub fn unsupported_err() -> io::Error {
io::Error::UNSUPPORTED_PLATFORM
}
}