Fix issue #13100 - std.process.setCLOEXEC() throws on invalid file descriptor

[kyllingstad]

https://issues.dlang.org/show_bug.cgi?id=13100

There are two cases in which the fcntl() calls may fail:

1. the file descriptor is invalid, in which case errno == EBADF,
2. they receive invalid arguments, in which case errno == EINVAL.

We just want to ignore the error in the former case, as evidenced by the bug report, and the latter means that we have an error in std.process, which is best handled by an assertion. (Note that it was never possible to catch the exception anyway, since it was thrown in the child process.)

[Hackerpilot]

Looks good to me.

[mihails-strasuns]

and the latter means that we have an error in std.process, which is best handled by an assertion

Just to make sure I understand it correctly - fcntl argument validity is 100% defined by internal std.process implementation and there is no way user input can affect this?

[kyllingstad]

fcntl argument validity is 100% defined by internal std.process implementation and there is no way user input can affect this?

That's right. It is private and only called from spawnProcess() with the standard input/output/error stream file descriptors as arguments. (In fact, it should probably be nested inside spawnProcess(), but that is for a different pull request.)

[mihails-strasuns]

Thanks, that nails it for me.

[mihails-strasuns]

Auto-merge toggled on

[kyllingstad]

@akushner: You're welcome!