rust/library/std/src/sys/unix/process/process_unix.rs, branch 1.48.0

Rollup merge of #77432 - tmiasko:posix-spawn-musl, r=cuviper

2020-10-02T18:27:11+00:00

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.

Auto merge of #77029 - ehuss:command-access, r=dtolnay

2020-10-02T07:51:24+00:00

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`](https://github.com/rust-lang/cargo/blob/13b73cdaf76b2d9182515c9cf26a8f68342d08ef/src/cargo/util/process_builder.rs#L105-L134) in Cargo. Possible concerns about the API: - Values with NULs on Unix will be returned as `""`. 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>`?). - `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

Use posix_spawn on musl targets

2020-10-01T00:00:00+00:00

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.

Use `rtassert!` instead of `assert!` from the child process after fork() in std::sys::unix::process::Command::spawn()

2020-09-29T07:16:46+00:00

`assert!` panics on failure, which is not signal-safe.

Add accessors to Command.

2020-09-27T01:58:38+00:00

Ignore unnecessary unsafe warnings

2020-09-11T17:12:06+00:00

This is a work-around for a libc issue: https://github.com/rust-lang/libc/issues/1888.

mv std libs to library/

2020-07-28T00:51:13+00:00