This may have inadvertently switched during the runtime overhaul, so this
switches TcpListener back to using sockets instead of file descriptors. This
also renames a bunch of variables called `fd` to `socket` to clearly show that
it's not a file descriptor.
Closes#19333
After the library successfully called fork(2), the child does several
setup works such as setting UID, GID and current directory before it
calls exec(2). When those setup works failed, the child exits but the
parent didn't call waitpid(2) and left it as a zombie.
This patch also add several sanity checks. They shouldn't make any
noticeable impact to runtime performance.
The new test case run-pass/wait-forked-but-failed-child.rs calls the ps
command to check if the new code can really reap a zombie. When
I intentionally create many zombies with my test program
./spawn-failure, The output of "ps -A -o pid,sid,command" should look
like this:
PID SID COMMAND
1 1 /sbin/init
2 0 [kthreadd]
3 0 [ksoftirqd/0]
...
12562 9237 ./spawn-failure
12563 9237 [spawn-failure] <defunct>
12564 9237 [spawn-failure] <defunct>
...
12592 9237 [spawn-failure] <defunct>
12593 9237 ps -A -o pid,sid,command
12884 12884 /bin/zsh
12922 12922 /bin/zsh
...
Filtering the output with the "SID" (session ID) column is a quick way
to tell if a process (zombie) was spawned by my own test program. Then
the number of "defunct" lines is the number of zombie children.
Signed-off-by: NODA, Kai <nodakai@gmail.com>
On *BSD systems, we can `open(2)` a directory and directly `read(2)` from it due to an old tradition. We should avoid doing so by explicitly calling `fstat(2)` to check the type of the opened file.
Opening a directory as a module file can't always be avoided. Even when there's no "path" attribute trick involved, there can always be a *directory* named `my_module.rs`.
Incidentally, remove unnecessary mutability of `&self` from `io::fs::File::stat()`.
This continues the work @thestinger started in #18885 (which hasn't landed yet, so wait for that to land before landing this one). Instead of adding more methods to `BufReader`, this just allows a `&[u8]` to be used directly as a `Reader`. It also adds an impl of `Writer` for `&mut [u8]`.
Adds the ability to use a custom allocator heap by passing either --cfg
external_crate and --extern external=<allocator_crate_name> or --cfg
external_funcs and defining the allocator functions prefixed by 'rust_'
somewhere.
This is useful for many reasons including OS/embedded development, and
allocator development and testing.
This closes#19168.
Please be careful reviewing this since this gets used all over the place. I've tested all the options and everything appears to be working though.
Comparison traits have gained an `Rhs` input parameter that defaults to `Self`. And now the comparison operators can be overloaded to work between different types. In particular, this PR allows the following operations (and their commutative versions):
- `&str` == `String` == `CowString`
- `&[A]` == `&mut [B]` == `Vec<C>` == `CowVec<D>` == `[E, ..N]` (for `N` up to 32)
- `&mut A` == `&B` (for `Sized` `A` and `B`)
Where `A`, `B`, `C`, `D`, `E` may be different types that implement `PartialEq`. For example, these comparisons are now valid: `string == "foo"`, and `vec_of_strings == ["Hello", "world"]`.
[breaking-change]s
Since the `==` may now work on different types, operations that relied on the old "same type restriction" to drive type inference, will need to be type annotated. These are the most common fallout cases:
- `some_vec == some_iter.collect()`: `collect` needs to be type annotated: `collect::<Vec<_>>()`
- `slice == &[a, b, c]`: RHS doesn't get coerced to an slice, use an array instead `[a, b, c]`
- `lhs == []`: Change expression to `lhs.is_empty()`
- `lhs == some_generic_function()`: Type annotate the RHS as necessary
cc #19148
r? @aturon
Implement the `Fn` trait for bare fn pointers in the compiler rather
than doing it using hard-coded impls. This means that it works also
for more complex fn types involving bound regions.
io::stdin returns a new `BufferedReader` each time it's called, which
results in some very confusing behavior with disappearing output. It now
returns a `StdinReader`, which wraps a global singleton
`Arc<Mutex<BufferedReader<StdReader>>`. `Reader` is implemented directly
on `StdinReader`. However, `Buffer` is not, as the `fill_buf` method is
fundamentaly un-thread safe. A `lock` method is defined on `StdinReader`
which returns a smart pointer wrapping the underlying `BufferedReader`
while guaranteeing mutual exclusion.
Code that treats the return value of io::stdin as implementing `Buffer`
will break. Add a call to `lock`:
```rust
io::stdin().lines()
// =>
io::stdin().lock().lines()
```
Closes#14434
[breaking-change]
This is a work in progress, but this should get *extensive* review, so I'm putting it up early and often.
This is the start of a draft of the new 'ownership guide,' which explains ownership, borrowing, etc. I'm feeling better about this framing than last time's, but we'll see.
We heavily rely on queries and fragments in the URL structure, so
it is desired to preserve them even in the redirects. The generated
redirect pages try to preserve them with scripts, which take
precedence over the original `Refresh` metadata. Non-scripting
browsers would continue to work (with no queries and fragments).
On *BSD systems, we can open(2) a directory and directly read(2) from
it due to an old tradition. We should avoid doing so by explicitly
calling fstat(2) to check the type of the opened file.
Opening a directory as a module file can't always be avoided.
Even when there's no "path" attribute trick involved, there can always
be a *directory* named "my_module.rs".
Fix#12460
Signed-off-by: NODA, Kai <nodakai@gmail.com>
This detects (a subset of) the cases when `transmute::<T, U>(x)` can be
lowered to a direct `bitcast T x to U` in LLVM. This assists with
efficiently handling a SIMD vector as multiple different types,
e.g. swapping bytes/words/double words around inside some larger vector
type.
C compilers like GCC and Clang handle integer vector types as `__m128i`
for all widths, and implicitly insert bitcasts as required. This patch
allows Rust to express this, even if it takes a bit of `unsafe`, whereas
previously it was impossible to do at all without inline assembly.
Example:
pub fn reverse_u32s(u: u64x2) -> u64x2 {
unsafe {
let tmp = mem::transmute::<_, u32x4>(u);
let swapped = u32x4(tmp.3, tmp.2, tmp.1, tmp.0);
mem::transmute::<_, u64x2>(swapped)
}
}
Compiling with `--opt-level=3` gives:
Before
define <2 x i64> @_ZN12reverse_u32s20hbdb206aba18a03d8tbaE(<2 x i64>) unnamed_addr #0 {
entry-block:
%1 = bitcast <2 x i64> %0 to i128
%u.0.extract.trunc = trunc i128 %1 to i32
%u.4.extract.shift = lshr i128 %1, 32
%u.4.extract.trunc = trunc i128 %u.4.extract.shift to i32
%u.8.extract.shift = lshr i128 %1, 64
%u.8.extract.trunc = trunc i128 %u.8.extract.shift to i32
%u.12.extract.shift = lshr i128 %1, 96
%u.12.extract.trunc = trunc i128 %u.12.extract.shift to i32
%2 = insertelement <4 x i32> undef, i32 %u.12.extract.trunc, i64 0
%3 = insertelement <4 x i32> %2, i32 %u.8.extract.trunc, i64 1
%4 = insertelement <4 x i32> %3, i32 %u.4.extract.trunc, i64 2
%5 = insertelement <4 x i32> %4, i32 %u.0.extract.trunc, i64 3
%6 = bitcast <4 x i32> %5 to <2 x i64>
ret <2 x i64> %6
}
_ZN12reverse_u32s20hbdb206aba18a03d8tbaE:
.cfi_startproc
movd %xmm0, %rax
punpckhqdq %xmm0, %xmm0
movd %xmm0, %rcx
movq %rcx, %rdx
shrq $32, %rdx
movq %rax, %rsi
shrq $32, %rsi
movd %eax, %xmm0
movd %ecx, %xmm1
punpckldq %xmm0, %xmm1
movd %esi, %xmm2
movd %edx, %xmm0
punpckldq %xmm2, %xmm0
punpckldq %xmm1, %xmm0
retq
After
define <2 x i64> @_ZN12reverse_u32s20hbdb206aba18a03d8tbaE(<2 x i64>) unnamed_addr #0 {
entry-block:
%1 = bitcast <2 x i64> %0 to <4 x i32>
%2 = shufflevector <4 x i32> %1, <4 x i32> undef, <4 x i32> <i32 3, i32 2, i32 1, i32 0>
%3 = bitcast <4 x i32> %2 to <2 x i64>
ret <2 x i64> %3
}
_ZN12reverse_u32s20hbdb206aba18a03d8tbaE:
.cfi_startproc
pshufd $27, %xmm0, %xmm0
retq
Part of enforcing capacity-related conventions, for #18424, the collections reform.
Implements `fn shrink_to_fit` for HashMap.
The `reserve` method now takes as an argument the *extra* space to reserve.
As an example of what this changes, the following code:
let x: [int ..4];
Currently spits out ‘expected `]`, found `..`’. However, a comma would also be
valid there, as would a number of other tokens. This change adjusts the parser
to produce more accurate errors, so that that example now produces ‘expected one
of `(`, `+`, `,`, `::`, or `]`, found `..`’.
This closes#19168. It's possible that if the downloading of `rustup.sh`
is interrupted, bad things could happen, such as running a naked
"rm -rf /" instead of "rm -rf /path/to/tmpdir". This wraps rustup.sh's
functionality in a function that gets called at the last time that should
protect us from these truncation errors.
