Normally, `Thread::spawn` takes care of setting the thread's name, if
one was provided, but since the main thread wasn't created by calling
`Thread::spawn`, we need to call that function in `std::rt::init`.
This is mainly useful for system tools like debuggers and profilers
which might show the thread name to a user. Prior to these changes, gdb
and WinDbg would show all thread names except the main thread's name to
a user. I've validated that this patch resolves the issue for both
debuggers.
Make HashMap fall back to RtlGenRandom if BCryptGenRandom fails
With PR #84096, Rust `std::collections::hash_map::RandomState` changed from using `RtlGenRandom()` ([msdn](https://docs.microsoft.com/en-us/windows/win32/api/ntsecapi/nf-ntsecapi-rtlgenrandom)) to `BCryptGenRandom()` ([msdn](https://docs.microsoft.com/en-us/windows/win32/api/bcrypt/nf-bcrypt-bcryptgenrandom)) as its source of secure randomness after much discussion ([here](https://github.com/rust-random/getrandom/issues/65#issuecomment-753634074), among other places).
Unfortunately, after that PR landed, Mozilla Firefox started experiencing fairly-rare crashes during startup while attempting to initialize the `env_logger` crate. ([docs for env_logger](https://docs.rs/env_logger/latest/env_logger/)) The root issue is that on some machines, `BCryptGenRandom()` will fail with an `Access is denied. (os error 5)` error message. ([Bugzilla issue 1754490](https://bugzilla.mozilla.org/show_bug.cgi?id=1754490)) (Discussion in issue #94098)
Note that this is happening upon startup of Firefox's unsandboxed Main Process, so this behavior is different and separate from previous issues ([like this](https://bugzilla.mozilla.org/show_bug.cgi?id=1746254)) where BCrypt DLLs were blocked by process sandboxing. In the case of sandboxing, we knew we were doing something abnormal and expected that we'd have to resort to abnormal measures to make it work.
However, in this case we are in a regular unsandboxed process just trying to initialize `env_logger` and getting a panic. We suspect that this may be caused by a virus scanner or some other security software blocking the loading of the BCrypt DLLs, but we're not completely sure as we haven't been able to replicate locally.
It is also possible that Firefox is not the only software affected by this; we just may be one of the pieces of Rust software that has the telemetry and crash reporting necessary to catch it.
I have read some of the historical discussion around using `BCryptGenRandom()` in Rust code, and I respect the decision that was made and agree that it was a good course of action, so I'm not trying to open a discussion about a return to `RtlGenRandom()`. Instead, I'd like to suggest that perhaps we use `RtlGenRandom()` as a "fallback RNG" in the case that BCrypt doesn't work.
This pull request implements this fallback behavior. I believe this would improve the robustness of this essential data structure within the standard library, and I see only 2 potential drawbacks:
1. Slight added overhead: It should be quite minimal though. The first call to `sys::rand::hashmap_random_keys()` will incur a bit of initialization overhead, and every call after will incur roughly 2 non-atomic global reads and 2 easily predictable branches. Both should be negligible compared to the actual cost of generating secure random numbers
2. `RtlGenRandom()` is deprecated by Microsoft: Technically true, but as mentioned in [this comment on GoLang](https://github.com/golang/go/issues/33542#issuecomment-626124873), this API is ubiquitous in Windows software and actually removing it would break lots of things. Also, Firefox uses it already in [our C++ code](https://searchfox.org/mozilla-central/rev/5f88c1d6977e03e22d3420d0cdf8ad0113c2eb31/mfbt/RandomNum.cpp#25), and [Chromium uses it in their code as well](https://source.chromium.org/chromium/chromium/src/+/main:base/rand_util_win.cc) (which transitively means that Microsoft uses it in their own web browser, Edge). If there did come a time when Microsoft truly removes this API, it should be easy enough for Rust to simply remove the fallback in the code I've added here
Issue #84096 changed the hashmap RNG to use BCryptGenRandom instead of
RtlGenRandom on Windows.
Mozilla Firefox started experiencing random failures in
env_logger::Builder::new() (Issue #94098) during initialization of their
unsandboxed main process with an "Access Denied" error message from
BCryptGenRandom(), which is used by the HashMap contained in
env_logger::Builder
The root cause appears to be a virus scanner or other software interfering
with BCrypt DLLs loading.
This change adds a fallback option if BCryptGenRandom is unusable for
whatever reason. It will fallback to RtlGenRandom in this case.
Fixes#94098
Windows: Make stdin pipes synchronous
Stdin pipes do not need to be used asynchronously within the standard library. This is a first step in making pipes mostly synchronous.
r? `@m-ou-se`
std: directly use pthread in UNIX parker implementation
`Mutex` and `Condvar` are being replaced by more efficient implementations, which need thread parking themselves (see #93740). Therefore we should use the `pthread` synchronization primitives directly. Also, we can avoid allocating the mutex and condition variable because the `Parker` struct is being placed in an `Arc` anyways.
This basically is just a copy of the current `Mutex` and `Condvar` code, which will however be removed (again, see #93740). An alternative implementation could be to use dedicated private `OsMutex` and `OsCondvar` types, but all the other platforms supported by std actually have their own thread parking primitives.
I used `Pin` to guarantee a stable address for the `Parker` struct, while the current implementation does not, rather using extra unsafe declaration. Since the thread struct is shared anyways, I assumed this would not add too much clutter while being clearer.
Mutex and Condvar are being replaced by more efficient implementations, which need thread parking themselves (see #93740). Therefore use the pthread synchronization primitives directly. Also, avoid allocating because the Parker struct is being placed in an Arc anyways.
Windows Command: Don't run batch files using verbatim paths
Fixes#95178
Note that the first commit does some minor refactoring (moving command line argument building to args.rs). The actual changes are in the second.
Reduce allocations for path conversions on Windows
Previously, UTF-8 to UTF-16 Path conversions on Windows unnecessarily allocate twice, as described in #96297. This commit fixes that issue.
Improve Windows path prefix parsing
This PR fixes improves parsing of Windows path prefixes. `parse_prefix` now supports both types of separators on Windows (`/` and `\`).
[fuchsia] Add implementation for `current_exe`
This implementation returns a best attempt at the current exe path. On
fuchsia, fdio will always use `argv[0]` as the process name and if it is
not set then an error will be returned. Because this is not guaranteed
to be the case, this implementation returns an error if `argv` does not
contain any elements.
remove_dir_all_recursive: treat ELOOP the same as ENOTDIR
On older Linux kernels (I tested on 4.4, corresponding to Ubuntu 16.04), opening a symlink using `O_DIRECTORY | O_NOFOLLOW` returns `ELOOP` instead of `ENOTDIR`. We should handle it the same, since a symlink is still not a directory and needs to be `unlink`ed.
Use sys::unix::locks::futex* on wasm+atomics.
This removes the wasm-specific lock implementations and instead re-uses the implementations from sys::unix.
Tracking issue: https://github.com/rust-lang/rust/issues/93740
cc ``@alexcrichton``
