This is much nicer for callers who want to short-circuit real I/O errors
with `?`, because they can write this
if let Some(status) = foo.try_wait()? {
...
} else {
...
}
instead of this
match foo.try_wait() {
Ok(status) => {
...
}
Err(err) if err.kind() == io::ErrorKind::WouldBlock => {
...
}
Err(err) => return Err(err),
}
The original design of `try_wait` was patterned after the `Read` and
`Write` traits, which support both blocking and non-blocking
implementations in a single API. But since `try_wait` is never blocking,
it makes sense to optimize for the non-blocking case.
Tracking issue: https://github.com/rust-lang/rust/issues/38903
Use less syscalls in `FileDesc::set_{nonblocking,cloexec}`
Only set the flags if they differ from what the OS reported, use
`FIONBIO` to atomically set the non-blocking IO flag on Linux.
Add peek APIs to std::net
Adds "peek" APIs to `std::net` sockets, including:
- `UdpSocket.peek()`
- `UdpSocket.peek_from()`
- `TcpStream.peek()`
These methods enable socket reads without side-effects. That is, repeated calls to `peek()` return identical data. This is accomplished by providing the POSIX flag `MSG_PEEK` to the underlying socket read operations.
This also moves the current implementation of `recv_from` out of the platform-independent `sys_common` and into respective `sys/windows` and `sys/unix` implementations. This allows for more platform-dependent implementations where necessary.
Fixes#38980
Expand documentation of process::exit and exec
Show a conventional way to use process::exit when destructors are considered important and also
mention that the same caveats wrt destructors apply to exec as well.
These methods enable socket reads without side-effects. That is,
repeated calls to peek() return identical data. This is accomplished
by providing the POSIX flag MSG_PEEK to the underlying socket read
operations.
This also moves the current implementation of recv_from out of the
platform-independent sys_common and into respective sys/windows and
sys/unix implementations. This allows for more platform-dependent
implementations.
Use less syscalls in `anon_pipe()`
Save a `ENOSYS` failure from `pipe2` and don't try again.
Use `cvt` instead of `cvt_r` for `pipe2` - `EINTR` is not an error
`pipe2` can return.
This commit adds support to the build system to execute test suites that cannot
run natively but can instead run inside of a QEMU emulator. A proof-of-concept
builder was added for the `arm-unknown-linux-gnueabihf` target to show off how
this might work.
In general the architecture is to have a server running inside of the emulator
which a local client connects to. The protocol between the server/client
supports compiling tests on the host and running them on the target inside the
emulator.
Closes#33114
Make backtraces work on Windows GNU targets again.
This is done by adding a function that can return a filename
to pass to backtrace_create_state. The filename is obtained in
a safe way by first getting the filename, locking the file so it can't
be moved, and then getting the filename again and making sure it's the same.
See: https://github.com/rust-lang/rust/pull/37359#issuecomment-260123399
Issue: #33985
Note though that this isn't that pretty...
I had to implement a `WideCharToMultiByte` wrapper function to convert to the ANSI code page. This will work better than only allowing ASCII provided that the ANSI code page is set to the user's local language, which is often the case.
Also, please make sure that I didn't break the Unix build.
This is done by adding a function that can return a filename
to pass to backtrace_create_state. The filename is obtained in
a safe way by first getting the filename, locking the file so it can't
be moved, and then getting the filename again and making sure it's the same.
See: https://github.com/rust-lang/rust/pull/37359#issuecomment-260123399
Issue: #33985
Show a conventional way to use process::exit when destructors are considered important and also
mention that the same caveats wrt destructors apply to exec as well.
This commit adds a new method to the `Child` type in the `std::process` module
called `try_wait`. This method is the same as `wait` except that it will not
block the calling thread and instead only attempt to collect the exit status. On
Unix this means that we call `waitpid` with the `WNOHANG` flag and on Windows it
just means that we pass a 0 timeout to `WaitForSingleObject`.
Currently it's possible to build this method out of tree, but it's unfortunately
tricky to do so. Specifically on Unix you essentially lose ownership of the pid
for the process once a call to `waitpid` has succeeded. Although `Child` tracks
this state internally to be resilient to multiple calls to `wait` or a `kill`
after a successful wait, if the child is waited on externally then the state
inside of `Child` is not updated. This means that external implementations of
this method must be extra careful to essentially not use a `Child`'s methods
after a call to `waitpid` has succeeded (even in a nonblocking fashion).
By adding this functionality to the standard library it should help canonicalize
these external implementations and ensure they can continue to robustly reuse
the `Child` type from the standard library without worrying about pid ownership.
Turns out that even though all these functions take a `size_t` they don't
actually work that well with anything larger than the maximum value of
`ssize_t`, the return value. Furthermore it looks like OSX rejects any
read/write requests larger than `INT_MAX - 1`. Handle all these cases by just
clamping the maximum size of a read/write on Unix to a platform-specific value.
Closes#38590
Removes magenta build warning.
Small bug fix to remove an unused type in the magenta process code that causes build failures for magenta's rustc.
r? @alexcrichton
@tedsta @raphlinus
Fuchsia support for std::process via liblaunchpad.
Now we can launch processes on Fuchsia via the Rust standard library! ... Mostly.
Right now, ~5% of the time, reading the stdout/stderr off the pipes will fail. Some Magenta kernel people think it's probably a bug in Magenta's pipes. I wrote a unit test that demonstrates the issue in C, which I was told will expedite a fix. https://fuchsia-review.googlesource.com/#/c/15628/
Hopefully this can get merged once the issue is fixed :)
@raphlinus
On unix like systems, the underlying file corresponding to any given path may
change at any time. This function makes it possible to set the permissions of
the a file corresponding to a `File` object even if its path changes.
The mx_cprng_draw syscall has changed signature to separate the status
and size return values, rather than multiplexing them into a single
value with errors interpreted as a negative value. This patch tracks
that change.
