Implement CommandExt::{exec, before_exec} #31409
Merged
Commits on Feb 10, 2016
-
std: Refactor process spawning on Unix
* Build up the argp/envp pointers while the `Command` is being constructed rather than only when `spawn` is called. This will allow better sharing of code between fork/exec paths. * Rename `child_after_fork` to `exec` and have it only perform the exec half of the spawning. This also means the return type has changed to `io::Error` rather than `!` to represent errors that happen.
-
std: Implement CommandExt::before_exec
This is a Unix-specific function which adds the ability to register a closure to run pre-exec to configure the child process as required (note that these closures are run post-fork). cc rust-lang#31398
-
std: Push Child's exit status to sys::process
On Unix we have to be careful to not call `waitpid` twice, but we don't have to be careful on Windows due to the way process handles work there. As a result the cached `Option<ExitStatus>` is only necessary on Unix, and it's also just an implementation detail of the Unix module. At the same time. also update some code in `kill` on Unix to avoid a wonky waitpid with WNOHANG. This was added in 0e190b9 to solve rust-lang#13124, but the `signal(0)` method is not supported any more so there's no need to for this workaround. I believe that this is no longer necessary as it's not really doing anything.
-
std: Rename Stdio::None to Stdio::Null
This better reflects what it's actually doing as we don't actually have an option for "leave this I/O slot as an empty hole".
-
std: Lift out Windows' CreateProcess lock a bit
The function `CreateProcess` is not itself unsafe to call from many threads, the article in question is pointing out that handles can be inherited by unintended child processes. This is basically the same race as the standard Unix open-then-set-cloexec race. Since the intention of the lock is to protect children from inheriting unintended handles, the lock is now lifted out to before the creation of the child I/O handles (which will all be inheritable). This will ensure that we only have one process in Rust at least creating inheritable handles at a time, preventing unintended inheritance to children.
-
std: Push process stdio setup in std::sys
Most of this is platform-specific anyway, and we generally have to jump through fewer hoops to do the equivalent operation on Windows. One benefit for Windows today is that this new structure avoids an extra `DuplicateHandle` when creating pipes. For Unix, however, the behavior should be the same. Note that this is just a pure refactoring, no functionality was added or removed.
-
std: Implement CommandExt::exec
This commit implements the `exec` function proposed in [RFC 1359][rfc] which is a function on the `CommandExt` trait to execute all parts of a `Command::spawn` without the `fork` on Unix. More details on the function itself can be found in the comments in the commit. [rfc]: rust-lang/rfcs#1359 cc rust-lang#31398
-
std: Use macros from libc instead of locally
Helps cut down on #[cfg]!
-
std: Move constant back to where it needs to be
Lost track of this during the std::process refactorings
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.