134 Commits

Author SHA1 Message Date
bors
32cbc65e6b Auto merge of #77380 - fusion-engineering-forks:unbox-the-mutex, r=dtolnay
Unbox mutexes and condvars on some platforms

Both mutexes and condition variables contained a Box containing the actual os-specific object. This was done because moving these objects may cause undefined behaviour on some platforms.

However, this is not needed on Windows[1], Wasm[2], cloudabi[2], and 'unsupported'[3], were the box was only needlessly making them less efficient.

This change gets rid of the box on those platforms.

On those platforms, `Condvar` can no longer verify it is only used with one `Mutex`, as mutexes no longer have a stable address. This was addressed and considered acceptable in #76932.

[1]\: https://docs.microsoft.com/en-us/windows/win32/api/synchapi/nf-synchapi-initializesrwlock
[2]\: These are just a single atomic integer together with futex wait/wake calls/instructions.
[3]\: The `unsupported` platform doesn't support multiple threads at all.
2020-10-04 06:48:17 +00:00
Jonas Schievink
ccc020ab42
Rollup merge of #77182 - GuillaumeGomez:missing-examples-fd-traits, r=pickfire
Add missing examples for Fd traits

Not sure what happened here... This is a reopening of #77142

r? @Dylan-DPC
2020-10-03 00:31:10 +02:00
Jonas Schievink
72d275d844
Rollup merge of #77432 - tmiasko:posix-spawn-musl, r=cuviper
Use posix_spawn on musl targets

The posix_spawn had been available in a form suitable for use in a
Command implementation since musl 0.9.12. Use it in a preference to a
fork when possible, to benefit from CLONE_VM|CLONE_VFORK used there.
2020-10-02 20:27:11 +02:00
Guillaume Gomez
d6b838b93a Simplify fd examples 2020-10-02 16:38:15 +02:00
bors
154f1f544d Auto merge of #77029 - ehuss:command-access, r=dtolnay
Add accessors to Command.

This adds some accessor methods to `Command` to provide a way to access the values set when building the `Command`. An example where this can be useful is to display the command to be executed. This is roughly based on the [`ProcessBuilder`](13b73cdaf7/src/cargo/util/process_builder.rs (L105-L134)) in Cargo.

Possible concerns about the API:
- Values with NULs on Unix will be returned as `"<string-with-nul>"`. I don't think it is practical to avoid this, since otherwise a whole separate copy of all the values would need to be kept in `Command`.
- Does not handle `arg0` on Unix. This can be awkward to support in `get_args` and is rarely used. I figure if someone really wants it, it can be added to `CommandExt` as a separate method.
- Does not offer a way to detect `env_clear`. I'm uncertain if it would be useful for anyone.
- Does not offer a way to get an environment variable by name (`get_env`). I figure this can be added later if anyone really wants it. I think the motivation for this is weak, though. Also, the API could be a little awkward (return a `Option<Option<&OsStr>>`?).
- `get_envs` could skip "cleared" entries and just return `&OsStr` values instead of `Option<&OsStr>`. I'm on the fence here. My use case is to display a shell command, and I only intend it to be roughly equivalent to the actual execution, and I probably won't display `None` entries. I erred on the side of providing extra information, but I suspect many situations will just filter out the `None`s.
- Could implement more iterator stuff (like `DoubleEndedIterator`).

I have not implemented new std items before, so I'm uncertain if the existing issue should be reused, or if a new tracking issue is needed.

cc #44434
2020-10-02 07:51:24 +00:00
Mara Bos
f3837e788b No longer put windows condvars in a box.
Windows condition variables are movable (while not borrowed) according
to their documentation.
2020-10-02 09:47:08 +02:00
Mara Bos
ec69a858e4 No longer put wasm condvars in a box.
These condvars are just an AtomicUsize, so can be moved without
problems.
2020-10-02 09:47:08 +02:00
Mara Bos
7f56a35411 No longer put condvars on the 'unsupported' platform in a box.
These condvars are unsupported and implemented as a ZST, so can be moved
without problems.
2020-10-02 09:47:08 +02:00
Mara Bos
5769a46788 No longer put cloudabi condvars in a box.
Cloudabi condvars may be moved safely.
2020-10-02 09:47:08 +02:00
Mara Bos
b181f5a923 Make it possible to have unboxed condvars on specific platforms.
This commit keeps all condvars boxed on all platforms, but makes it
trivial to remove the box on some platforms later.
2020-10-02 09:47:08 +02:00
Mara Bos
dc81cbdcb1 No longer put windows mutexes in a box.
Windows SRW locks are movable (while not borrowed) according to their
documentation.
2020-10-02 09:47:08 +02:00
Mara Bos
4f1353e54f No longer put wasm mutexes in a box.
These mutexes are just an AtomicUsize, so can be moved without
problems.
2020-10-02 09:47:08 +02:00
Mara Bos
2f0386771d No longer put mutexes on the 'unsupported' platform in a box.
These mutexes are just a bool (in a cell), so can be moved without
problems.
2020-10-02 09:47:08 +02:00
Mara Bos
def5188ca8 No longer put cloudabi mutexes in a box.
Cloudabi mutexes may be moved safely.
2020-10-02 09:47:08 +02:00
Mara Bos
58deb7001d Make it possible to have unboxed mutexes on specific platforms.
This commit keeps all mutexes boxed on all platforms, but makes it
trivial to remove the box on some platforms later.
2020-10-02 09:47:08 +02:00
Yuki Okushi
1c4a5f8d1e
Rollup merge of #77147 - fusion-engineering-forks:static-mutex, r=dtolnay
Split sys_common::Mutex in StaticMutex and MovableMutex.

The (unsafe) `Mutex` from `sys_common` had a rather complicated interface. You were supposed to call `init()` manually, unless you could guarantee it was neither moved nor used reentrantly.

Calling `destroy()` was also optional, although it was unclear if 1) resources might be leaked or not, and 2) if `destroy()` should only be called when `init()` was called.

This allowed for a number of interesting (confusing?) different ways to use this `Mutex`, all captured in a single type.

In practice, this type was only ever used in two ways:

1. As a static variable. In this case, neither `init()` nor `destroy()` are called. The variable is never moved, and it is never used reentrantly. It is only ever locked using the `LockGuard`, never with `raw_lock`.

2. As a `Box`ed variable. In this case, both `init()` and `destroy()` are called, it will be moved and possibly used reentrantly.

No other combinations are used anywhere in `std`.

This change simplifies things by splitting this `Mutex` type into two types matching the two use cases: `StaticMutex` and `MovableMutex`.

The interface of both new types is now both safer and simpler. The first one does not call nor expose `init`/`destroy`, and the second one calls those automatically in its `new()` and `Drop` functions. Also, the locking functions of `MovableMutex` are no longer unsafe.

---

This will also make it easier to conditionally box mutexes later, by moving that decision into sys/sys_common. Some of the mutex implementations (at least those of Wasm and 'sys/unsupported') are safe to move, so wouldn't need a box. ~~(But that's blocked on  #76932 for now.)~~ (See #77380.)
2020-10-02 08:25:15 +09:00
Yuki Okushi
00b3450bbc
Rollup merge of #76979 - fusion-engineering-forks:windows-fallback-check, r=dtolnay
Improve std::sys::windows::compat

Improves the compat_fn macro in sys::windows, which is used for conditionally loading APIs that might not be available.

- The module (dll) name can now be any string, not just an ident. (Not all Windows api modules are valid Rust identifiers. E.g. `WaitOnAddress` comes from `API-MS-Win-Core-Synch-l1-2-0.dll`.)
- Adds `FuncName::is_available()` for checking if a function is really available without having to do a duplicate lookup.
- Add comment explaining the lack of locking.
- Use `$_:block` to simplify the macro_rules.
- Apply `allow(unused_variables)` only to the fallback instead of everything.

---

The second point (`is_available()`) simplifies code that needs to pick an implementation depening on what is available, like `sys/windows/mutex.rs`. Before this change, it'd do its own lookup and keep its own `AtomicUsize` to track the result. Now it can just use `c::AcquireSRWLockExclusive::is_available()` directly.

This will also be useful when park/unpark/CondVar/etc. get improved implementations (e.g. from parking_lot or something else), as the best APIs for those are not available before Windows 8.
2020-10-02 08:25:11 +09:00
bors
2ad6187ce5 Auto merge of #76969 - withoutboats:rawfd-refexive-traits, r=dtolnay
Make RawFd implement the RawFd traits

This PR makes `RawFd` implement `AsRawFd`, `IntoRawFd` and `FromRawFd`, so it can be passed to interfaces that use one of those traits as a bound.
2020-10-01 15:39:33 +00:00
Mara Bos
63b6007d5b Work around potential merging/duplication issues in sys/windows/compat. 2020-10-01 16:52:11 +02:00
Mara Bos
09cbaf4367 Formatting. 2020-10-01 16:08:58 +02:00
Mara Bos
93310efdbe Use AcquireSRWLockExclusive::is_available() instead of an extra lookup. 2020-10-01 16:08:58 +02:00
Mara Bos
8b2bdfd453 Improve std::sys::windows::compat.
- Module name can now be any string, not just an ident.
  (Not all Windows api modules are valid Rust identifiers.)
- Adds c::FuncName::is_available() for checking if a function is really
  available without having to do a duplicate lookup.
- Add comment explaining the lack of locking.
- Use `$_:block` to simplify the macro_rules.
- Apply allow(unused_variables) only to the fallback instead of
  everything.
2020-10-01 16:08:57 +02:00
bors
782013564e Auto merge of #76919 - fusion-engineering-forks:thread-parker, r=dtolnay
Use futex-based thread::park/unpark on Linux.

This moves the parking/unparking logic out of `thread/mod.rs` into a module named `thread_parker` in `sys_common`. The current implementation is moved to `sys_common/thread_parker/generic.rs` and the new implementation using futexes is added in `sys_common/thread_parker/futex.rs`.
2020-10-01 13:21:34 +00:00
Tomasz Miąsko
9845e7d5fb Use posix_spawn on musl targets
The posix_spawn had been available in a form suitable for use in a
Command implementation since musl 0.9.12. Use it in a preference to a
fork when possible, to benefit from CLONE_VM|CLONE_VFORK used there.
2020-10-01 00:00:00 +00:00
Jonas Schievink
c46f5784a6
Rollup merge of #77328 - hyd-dev:assert-to-rtassert, r=Amanieu
Use `rtassert!` instead of `assert!` from the child process after fork() in std::sys::unix::process::Command::spawn()

As discussed in #73894, `assert!` panics on failure, which is not signal-safe, and `rtassert!` is a suitable replacement.

Fixes #73894.

r? @Amanieu @cuviper @joshtriplett
2020-09-30 20:56:15 +02:00
bors
c0127e4dbf Auto merge of #77292 - lzutao:std_asm, r=Amanieu
Prefer asm! in std - all in sgx module

Similar to the change in #76669 but all `llvm_asm!` is gate in x86/x86_64 target.
Godbolt:
- https://rust.godbolt.org/z/h7nG1h
- https://rust.godbolt.org/z/xx39hW
2020-09-30 05:27:16 +00:00
hyd-dev
a2526b416f
Use rtassert! instead of assert! from the child process after fork() in std::sys::unix::process::Command::spawn()
`assert!` panics on failure, which is not signal-safe.
2020-09-29 15:16:46 +08:00
Lzu Tao
d4772014d9 Prefer asm! in std - all in sgx module 2020-09-28 13:08:34 +00:00
Ralf Jung
dc8414b607 fix building libstd for Miri on macOS 2020-09-28 10:32:05 +02:00
Tomasz Miąsko
7d98d2207a Reopen standard streams when they are closed on Unix
The syscalls returning a new file descriptors generally use
lowest-numbered file descriptor not currently opened, without any
exceptions for those corresponding to the standard streams.

Previously when any of standard streams has been closed before starting
the application, operations on std::io::{stderr,stdin,stdout} objects
were likely to operate on other logically unrelated file resources
opened afterwards.

Avoid the issue by reopening the standard streams when they are closed.
2020-09-27 22:55:43 +02:00
Mara Bos
485f882d77 Check conversion from Duration to timespec in futex_wait. 2020-09-27 11:56:43 +02:00
Mara Bos
2cf0f64722 Move linux-specific futex code into sys module. 2020-09-27 11:56:43 +02:00
Mara Bos
6f6336b4a1 Split sys_common::Mutex in StaticMutex and MovableMutex.
The (unsafe) Mutex from sys_common had a rather complicated interface.
You were supposed to call init() manually, unless you could guarantee it
was neither moved nor used reentrantly.

Calling `destroy()` was also optional, although it was unclear if 1)
resources might be leaked or not, and 2) if destroy() should only be
called when `init()` was called.

This allowed for a number of interesting (confusing?) different ways to
use this Mutex, all captured in a single type.

In practice, this type was only ever used in two ways:

1. As a static variable. In this case, neither init() nor destroy() are
   called. The variable is never moved, and it is never used
   reentrantly. It is only ever locked using the LockGuard, never with
   raw_lock.

2. As a Boxed variable. In this case, both init() and destroy() are
   called, it will be moved and possibly used reentrantly.

No other combinations are used anywhere in `std`.

This change simplifies things by splitting this Mutex type into
two types matching the two use cases: StaticMutex and MovableMutex.

The interface of both new types is now both safer and simpler. The first
one does not call nor expose init/destroy, and the second one calls
those automatically in its new() and Drop functions. Also, the locking
functions of MovableMutex are no longer unsafe.
2020-09-27 10:05:56 +02:00
Eric Huss
c297e20e03 Add accessors to Command. 2020-09-26 18:58:38 -07:00
Guillaume Gomez
980e1ff40f Add missing examples for Fd traits 2020-09-25 21:20:42 +02:00
Joshua Nelson
15f08d6ddf
Revert "Function to convert OpenOptions to c_int" 2020-09-22 23:07:30 -04:00
bors
e0bc267512 Auto merge of #76110 - FedericoPonzi:convert-openoptions-cint, r=JoshTriplett
Function to convert OpenOptions to c_int

Fixes: #74943
The creation_mode and access_mode function were already available in the OpenOptions struct, but currently private. I've added a new free functions to unix/fs.rs which takes the OpenOptions, and returns the c_int to be used as parameter for the `open` call.
2020-09-22 13:02:02 +00:00
Federico Ponzi
2f5192280f
enable unstable open_options_ext_as_flags feature in doc comments 2020-09-22 09:54:36 +01:00
Ralf Jung
ae4b677aa8
Rollup merge of #76521 - tavianator:fix-pthread-getattr-destroy, r=Amanieu
Fix segfault if pthread_getattr_np fails

glibc [destroys][1] the passed pthread_attr_t if pthread_getattr_np()
fails.  Destroying it again leads to a segfault.  Fix it by only
destroying it on success for glibc.

[1]: https://sourceware.org/git/?p=glibc.git;a=blob;f=nptl/pthread_getattr_np.c;h=ce437205e41dc05653e435f6188768cccdd91c99;hb=HEAD#l205
2020-09-21 15:30:37 +02:00
Without Boats
35b30e29bf try again to appease tidy 2020-09-20 14:38:59 +02:00
Without Boats
3fe279fc65 spend another CI build to delete a double newline 2020-09-20 14:04:23 +02:00
Without Boats
acc136ce0a fix typos 2020-09-20 13:32:49 +02:00
Without Boats
82f5928ca6 Make RawFd implement the RawFd traits 2020-09-20 13:21:42 +02:00
rijenkii
a60f97849b
Add tracking issue for feature(unix_socket_peek) 2020-09-19 21:55:01 +07:00
bors
f3c923a13a Auto merge of #76645 - fusion-engineering-forks:windows-lock, r=kennytm
Small cleanups in Windows Mutex.

 - Move `held` into the boxed part, since the SRW lock implementation does not use this. This makes the Mutex 50% smaller.
 - Use `Cell` instead of `UnsafeCell` for `held`, such that `.replace()` can be used.
 - Add some comments.
 - Avoid creating multiple `&mut`s to the critical section object in `ReentrantMutex`.
2020-09-17 19:23:58 +00:00
Tyler Mandry
ab207743af
Rollup merge of #76758 - adamlesinski:clone_clock, r=tmandry
[fuchsia] Propagate the userspace UTC clock

On Fuchsia, spawning a subprocess does not automatically
clone all of the parent process' capabilities. UTC time on
Fuchsia is managed by a top-level userspace clock capability
that is cloned and passed to subprocesses.

This change ensures that any Rust subprocess gets access to the
UTC clock, if the parent had access to it. This is critical for
tests, which on Fuchsia, use panic=abort and spawn subprocesses
per test.
2020-09-16 12:24:19 -07:00
Mara Bos
0bb96e7490 Avoid creating &muts in Windows ReentrantMutex. 2020-09-16 21:16:32 +02:00
Mara Bos
3fadc603ab Don't use mut in Windows Mutex. 2020-09-16 21:09:53 +02:00
Federico Ponzi
70292d4506
Sets as_flags as unstable 2020-09-16 19:40:44 +02:00
Dylan DPC
034af08e14
Rollup merge of #75749 - ehuss:consolidate-sys, r=alexcrichton
Consolidate some duplicate code in the sys modules.

This consolidates some modules which were duplicated throughout the sys module. The intent is to make it easier to update and maintain this code. This mainly affects the wasi, sgx, and "unsupported" targets.

I explicitly skipped hermit, cloudabi, and vxworks. These tier-3 targets have copied large sections of the sys tree. I don't think they should have, but I don't want to put effort into changing them. It also doesn't help that there aren't any scripts or instructions for building them.

There are still sections of duplicate code here and there, but this PR covers the easy parts where entire modules are the same.
2020-09-16 01:30:34 +02:00