1#![allow(missing_docs, nonstandard_style)]
2
3use crate::io::ErrorKind;
4
5#[cfg(not(target_os = "espidf"))]
6#[macro_use]
7pub mod weak;
8
9pub mod args;
10pub mod env;
11pub mod fd;
12#[cfg(target_os = "fuchsia")]
13pub mod fuchsia;
14pub mod futex;
15#[cfg(any(target_os = "linux", target_os = "android"))]
16pub mod kernel_copy;
17#[cfg(target_os = "linux")]
18pub mod linux;
19pub mod os;
20pub mod pipe;
21pub mod stack_overflow;
22pub mod sync;
23pub mod thread;
24pub mod thread_parking;
25pub mod time;
26
27#[cfg(target_os = "espidf")]
28pub fn init(_argc: isize, _argv: *const *const u8, _sigpipe: u8) {}
29
30#[cfg(not(target_os = "espidf"))]
31// SAFETY: must be called only once during runtime initialization.
32// NOTE: this is not guaranteed to run, for example when Rust code is called externally.
33// See `fn init()` in `library/std/src/rt.rs` for docs on `sigpipe`.
34pub unsafe fn init(argc: isize, argv: *const *const u8, sigpipe: u8) {
35 // The standard streams might be closed on application startup. To prevent
36 // std::io::{stdin, stdout,stderr} objects from using other unrelated file
37 // resources opened later, we reopen standards streams when they are closed.
38 sanitize_standard_fds();
39
40 // By default, some platforms will send a *signal* when an EPIPE error
41 // would otherwise be delivered. This runtime doesn't install a SIGPIPE
42 // handler, causing it to kill the program, which isn't exactly what we
43 // want!
44 //
45 // Hence, we set SIGPIPE to ignore when the program starts up in order
46 // to prevent this problem. Use `-Zon-broken-pipe=...` to alter this
47 // behavior.
48 reset_sigpipe(sigpipe);
49
50 stack_overflow::init();
51 args::init(argc, argv);
52
53 // Normally, `thread::spawn` will call `Thread::set_name` but since this thread
54 // already exists, we have to call it ourselves. We only do this on Apple targets
55 // because some unix-like operating systems such as Linux share process-id and
56 // thread-id for the main thread and so renaming the main thread will rename the
57 // process and we only want to enable this on platforms we've tested.
58 if cfg!(target_vendor = "apple") {
59 thread::Thread::set_name(&c"main");
60 }
61
62 unsafe fn sanitize_standard_fds() {
63 // fast path with a single syscall for systems with poll()
64 #[cfg(not(any(
65 miri,
66 target_os = "emscripten",
67 target_os = "fuchsia",
68 target_os = "vxworks",
69 target_os = "redox",
70 target_os = "l4re",
71 target_os = "horizon",
72 target_os = "vita",
73 target_os = "rtems",
74 // The poll on Darwin doesn't set POLLNVAL for closed fds.
75 target_vendor = "apple",
76 )))]
77 'poll: {
78 #[cfg(not(all(target_os = "linux", target_env = "gnu")))]
79 use libc::open as open64;
80 #[cfg(all(target_os = "linux", target_env = "gnu"))]
81 use libc::open64;
82
83 use crate::sys::os::errno;
84 let pfds: &mut [_] = &mut [
85 libc::pollfd { fd: 0, events: 0, revents: 0 },
86 libc::pollfd { fd: 1, events: 0, revents: 0 },
87 libc::pollfd { fd: 2, events: 0, revents: 0 },
88 ];
89
90 while libc::poll(pfds.as_mut_ptr(), 3, 0) == -1 {
91 match errno() {
92 libc::EINTR => continue,
93 #[cfg(target_vendor = "unikraft")]
94 libc::ENOSYS => {
95 // Not all configurations of Unikraft enable `LIBPOSIX_EVENT`.
96 break 'poll;
97 }
98 libc::EINVAL | libc::EAGAIN | libc::ENOMEM => {
99 // RLIMIT_NOFILE or temporary allocation failures
100 // may be preventing use of poll(), fall back to fcntl
101 break 'poll;
102 }
103 _ => libc::abort(),
104 }
105 }
106 for pfd in pfds {
107 if pfd.revents & libc::POLLNVAL == 0 {
108 continue;
109 }
110 if open64(c"/dev/null".as_ptr(), libc::O_RDWR, 0) == -1 {
111 // If the stream is closed but we failed to reopen it, abort the
112 // process. Otherwise we wouldn't preserve the safety of
113 // operations on the corresponding Rust object Stdin, Stdout, or
114 // Stderr.
115 libc::abort();
116 }
117 }
118 return;
119 }
120
121 // fallback in case poll isn't available or limited by RLIMIT_NOFILE
122 #[cfg(not(any(
123 // The standard fds are always available in Miri.
124 miri,
125 target_os = "emscripten",
126 target_os = "fuchsia",
127 target_os = "vxworks",
128 target_os = "l4re",
129 target_os = "horizon",
130 target_os = "vita",
131 )))]
132 {
133 #[cfg(not(all(target_os = "linux", target_env = "gnu")))]
134 use libc::open as open64;
135 #[cfg(all(target_os = "linux", target_env = "gnu"))]
136 use libc::open64;
137
138 use crate::sys::os::errno;
139 for fd in 0..3 {
140 if libc::fcntl(fd, libc::F_GETFD) == -1 && errno() == libc::EBADF {
141 if open64(c"/dev/null".as_ptr(), libc::O_RDWR, 0) == -1 {
142 // If the stream is closed but we failed to reopen it, abort the
143 // process. Otherwise we wouldn't preserve the safety of
144 // operations on the corresponding Rust object Stdin, Stdout, or
145 // Stderr.
146 libc::abort();
147 }
148 }
149 }
150 }
151 }
152
153 unsafe fn reset_sigpipe(#[allow(unused_variables)] sigpipe: u8) {
154 #[cfg(not(any(
155 target_os = "emscripten",
156 target_os = "fuchsia",
157 target_os = "horizon",
158 target_os = "vxworks",
159 target_os = "vita",
160 // Unikraft's `signal` implementation is currently broken:
161 // https://github.com/unikraft/lib-musl/issues/57
162 target_vendor = "unikraft",
163 )))]
164 {
165 // We don't want to add this as a public type to std, nor do we
166 // want to `include!` a file from the compiler (which would break
167 // Miri and xargo for example), so we choose to duplicate these
168 // constants from `compiler/rustc_session/src/config/sigpipe.rs`.
169 // See the other file for docs. NOTE: Make sure to keep them in
170 // sync!
171 mod sigpipe {
172 pub const DEFAULT: u8 = 0;
173 pub const INHERIT: u8 = 1;
174 pub const SIG_IGN: u8 = 2;
175 pub const SIG_DFL: u8 = 3;
176 }
177
178 let (sigpipe_attr_specified, handler) = match sigpipe {
179 sigpipe::DEFAULT => (false, Some(libc::SIG_IGN)),
180 sigpipe::INHERIT => (true, None),
181 sigpipe::SIG_IGN => (true, Some(libc::SIG_IGN)),
182 sigpipe::SIG_DFL => (true, Some(libc::SIG_DFL)),
183 _ => unreachable!(),
184 };
185 if sigpipe_attr_specified {
186 ON_BROKEN_PIPE_FLAG_USED.store(true, crate::sync::atomic::Ordering::Relaxed);
187 }
188 if let Some(handler) = handler {
189 rtassert!(signal(libc::SIGPIPE, handler) != libc::SIG_ERR);
190 #[cfg(target_os = "hurd")]
191 {
192 rtassert!(signal(libc::SIGLOST, handler) != libc::SIG_ERR);
193 }
194 }
195 }
196 }
197}
198
199// This is set (up to once) in reset_sigpipe.
200#[cfg(not(any(
201 target_os = "espidf",
202 target_os = "emscripten",
203 target_os = "fuchsia",
204 target_os = "horizon",
205 target_os = "vxworks",
206 target_os = "vita",
207)))]
208static ON_BROKEN_PIPE_FLAG_USED: crate::sync::atomic::AtomicBool =
209 crate::sync::atomic::AtomicBool::new(false);
210
211#[cfg(not(any(
212 target_os = "espidf",
213 target_os = "emscripten",
214 target_os = "fuchsia",
215 target_os = "horizon",
216 target_os = "vxworks",
217 target_os = "vita",
218 target_os = "nuttx",
219)))]
220pub(crate) fn on_broken_pipe_flag_used() -> bool {
221 ON_BROKEN_PIPE_FLAG_USED.load(order:crate::sync::atomic::Ordering::Relaxed)
222}
223
224// SAFETY: must be called only once during runtime cleanup.
225// NOTE: this is not guaranteed to run, for example when the program aborts.
226pub unsafe fn cleanup() {
227 stack_overflow::cleanup();
228}
229
230#[allow(unused_imports)]
231pub use libc::signal;
232
233#[inline]
234pub(crate) fn is_interrupted(errno: i32) -> bool {
235 errno == libc::EINTR
236}
237
238pub fn decode_error_kind(errno: i32) -> ErrorKind {
239 use ErrorKind::*;
240 match errno as libc::c_int {
241 libc::E2BIG => ArgumentListTooLong,
242 libc::EADDRINUSE => AddrInUse,
243 libc::EADDRNOTAVAIL => AddrNotAvailable,
244 libc::EBUSY => ResourceBusy,
245 libc::ECONNABORTED => ConnectionAborted,
246 libc::ECONNREFUSED => ConnectionRefused,
247 libc::ECONNRESET => ConnectionReset,
248 libc::EDEADLK => Deadlock,
249 libc::EDQUOT => QuotaExceeded,
250 libc::EEXIST => AlreadyExists,
251 libc::EFBIG => FileTooLarge,
252 libc::EHOSTUNREACH => HostUnreachable,
253 libc::EINTR => Interrupted,
254 libc::EINVAL => InvalidInput,
255 libc::EISDIR => IsADirectory,
256 libc::ELOOP => FilesystemLoop,
257 libc::ENOENT => NotFound,
258 libc::ENOMEM => OutOfMemory,
259 libc::ENOSPC => StorageFull,
260 libc::ENOSYS => Unsupported,
261 libc::EMLINK => TooManyLinks,
262 libc::ENAMETOOLONG => InvalidFilename,
263 libc::ENETDOWN => NetworkDown,
264 libc::ENETUNREACH => NetworkUnreachable,
265 libc::ENOTCONN => NotConnected,
266 libc::ENOTDIR => NotADirectory,
267 #[cfg(not(target_os = "aix"))]
268 libc::ENOTEMPTY => DirectoryNotEmpty,
269 libc::EPIPE => BrokenPipe,
270 libc::EROFS => ReadOnlyFilesystem,
271 libc::ESPIPE => NotSeekable,
272 libc::ESTALE => StaleNetworkFileHandle,
273 libc::ETIMEDOUT => TimedOut,
274 libc::ETXTBSY => ExecutableFileBusy,
275 libc::EXDEV => CrossesDevices,
276 libc::EINPROGRESS => InProgress,
277
278 libc::EACCES | libc::EPERM => PermissionDenied,
279
280 // These two constants can have the same value on some systems,
281 // but different values on others, so we can't use a match
282 // clause
283 x if x == libc::EAGAIN || x == libc::EWOULDBLOCK => WouldBlock,
284
285 _ => Uncategorized,
286 }
287}
288
289#[doc(hidden)]
290pub trait IsMinusOne {
291 fn is_minus_one(&self) -> bool;
292}
293
294macro_rules! impl_is_minus_one {
295 ($($t:ident)*) => ($(impl IsMinusOne for $t {
296 fn is_minus_one(&self) -> bool {
297 *self == -1
298 }
299 })*)
300}
301
302impl_is_minus_one! { i8 i16 i32 i64 isize }
303
304/// Converts native return values to Result using the *-1 means error is in `errno`* convention.
305/// Non-error values are `Ok`-wrapped.
306pub fn cvt<T: IsMinusOne>(t: T) -> crate::io::Result<T> {
307 if t.is_minus_one() { Err(crate::io::Error::last_os_error()) } else { Ok(t) }
308}
309
310/// `-1` → look at `errno` → retry on `EINTR`. Otherwise `Ok()`-wrap the closure return value.
311pub fn cvt_r<T, F>(mut f: F) -> crate::io::Result<T>
312where
313 T: IsMinusOne,
314 F: FnMut() -> T,
315{
316 loop {
317 match cvt(f()) {
318 Err(ref e: &Error) if e.is_interrupted() => {}
319 other: Result => return other,
320 }
321 }
322}
323
324#[allow(dead_code)] // Not used on all platforms.
325/// Zero means `Ok()`, all other values are treated as raw OS errors. Does not look at `errno`.
326pub fn cvt_nz(error: libc::c_int) -> crate::io::Result<()> {
327 if error == 0 { Ok(()) } else { Err(crate::io::Error::from_raw_os_error(code:error)) }
328}
329
330// libc::abort() will run the SIGABRT handler. That's fine because anyone who
331// installs a SIGABRT handler already has to expect it to run in Very Bad
332// situations (eg, malloc crashing).
333//
334// Current glibc's abort() function unblocks SIGABRT, raises SIGABRT, clears the
335// SIGABRT handler and raises it again, and then starts to get creative.
336//
337// See the public documentation for `intrinsics::abort()` and `process::abort()`
338// for further discussion.
339//
340// There is confusion about whether libc::abort() flushes stdio streams.
341// libc::abort() is required by ISO C 99 (7.14.1.1p5) to be async-signal-safe,
342// so flushing streams is at least extremely hard, if not entirely impossible.
343//
344// However, some versions of POSIX (eg IEEE Std 1003.1-2001) required abort to
345// do so. In 1003.1-2004 this was fixed.
346//
347// glibc's implementation did the flush, unsafely, before glibc commit
348// 91e7cf982d01 `abort: Do not flush stdio streams [BZ #15436]` by Florian
349// Weimer. According to glibc's NEWS:
350//
351// The abort function terminates the process immediately, without flushing
352// stdio streams. Previous glibc versions used to flush streams, resulting
353// in deadlocks and further data corruption. This change also affects
354// process aborts as the result of assertion failures.
355//
356// This is an accurate description of the problem. The only solution for
357// program with nontrivial use of C stdio is a fixed libc - one which does not
358// try to flush in abort - since even libc-internal errors, and assertion
359// failures generated from C, will go via abort().
360//
361// On systems with old, buggy, libcs, the impact can be severe for a
362// multithreaded C program. It is much less severe for Rust, because Rust
363// stdlib doesn't use libc stdio buffering. In a typical Rust program, which
364// does not use C stdio, even a buggy libc::abort() is, in fact, safe.
365pub fn abort_internal() -> ! {
366 unsafe { libc::abort() }
367}
368
369cfg_if::cfg_if! {
370 if #[cfg(target_os = "android")] {
371 #[link(name = "dl", kind = "static", modifiers = "-bundle",
372 cfg(target_feature = "crt-static"))]
373 #[link(name = "dl", cfg(not(target_feature = "crt-static")))]
374 #[link(name = "log", cfg(not(target_feature = "crt-static")))]
375 unsafe extern "C" {}
376 } else if #[cfg(target_os = "freebsd")] {
377 #[link(name = "execinfo")]
378 #[link(name = "pthread")]
379 unsafe extern "C" {}
380 } else if #[cfg(target_os = "netbsd")] {
381 #[link(name = "pthread")]
382 #[link(name = "rt")]
383 unsafe extern "C" {}
384 } else if #[cfg(any(target_os = "dragonfly", target_os = "openbsd", target_os = "cygwin"))] {
385 #[link(name = "pthread")]
386 unsafe extern "C" {}
387 } else if #[cfg(target_os = "solaris")] {
388 #[link(name = "socket")]
389 #[link(name = "posix4")]
390 #[link(name = "pthread")]
391 #[link(name = "resolv")]
392 unsafe extern "C" {}
393 } else if #[cfg(target_os = "illumos")] {
394 #[link(name = "socket")]
395 #[link(name = "posix4")]
396 #[link(name = "pthread")]
397 #[link(name = "resolv")]
398 #[link(name = "nsl")]
399 // Use libumem for the (malloc-compatible) allocator
400 #[link(name = "umem")]
401 unsafe extern "C" {}
402 } else if #[cfg(target_vendor = "apple")] {
403 // Link to `libSystem.dylib`.
404 //
405 // Don't get confused by the presence of `System.framework`,
406 // it is a deprecated wrapper over the dynamic library.
407 #[link(name = "System")]
408 unsafe extern "C" {}
409 } else if #[cfg(target_os = "fuchsia")] {
410 #[link(name = "zircon")]
411 #[link(name = "fdio")]
412 unsafe extern "C" {}
413 } else if #[cfg(all(target_os = "linux", target_env = "uclibc"))] {
414 #[link(name = "dl")]
415 unsafe extern "C" {}
416 } else if #[cfg(target_os = "vita")] {
417 #[link(name = "pthread", kind = "static", modifiers = "-bundle")]
418 unsafe extern "C" {}
419 }
420}
421
422#[cfg(any(target_os = "espidf", target_os = "horizon", target_os = "vita", target_os = "nuttx"))]
423pub mod unsupported {
424 use crate::io;
425
426 pub fn unsupported<T>() -> io::Result<T> {
427 Err(unsupported_err())
428 }
429
430 pub fn unsupported_err() -> io::Error {
431 io::Error::UNSUPPORTED_PLATFORM
432 }
433}
434

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