fix: add CLOEXEC flag to socket created directly #550
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Go runtime adds `CLOEXEC` flags automatically, but when using raw syscalls, we have to do it manually. Without this flag, file descriptors leak to the child processes. Signed-off-by: Andrey Smirnov <[email protected]>
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| return fd, nil | ||
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| if err == unix.EINVAL || err == unix.EPROTONOSUPPORT { |
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EINVAL seems awfully wide an error to catch for this I think, especially with having to take the forklock in the fallback case.
Can this be further narrowed per-platform with build tags? Afaict linux and all the go-supported bsds support SOCK_CLOEXEC, so the only actually relevant platform would be darwin, non-illumos solaris (before 11.4 according to net source ), maybe AIX?
It looks like GOOS=darwin doesn't even define unix.SOCK_CLOEXEC so this workaround won't even compile there (would it be necessary? I'm not sure)
I'd be inclined to not support it at all, I don't think any of these platforms are tested at all anyway
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Darwin should support CLOEXEC I believe starting with some version, but I haven't tested it.
There's a similar workaround in Go runtime, and this code is loosely based on https://github.com/mdlayher/socket/blob/9c51a391be6c6bc5b7ce52f328497931c5e97733/conn.go#L254-L303
But I'm happy to drop it and simply do | unix.O_CLOEXEC
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yes, SOCK_CLOEXEC is missing on Darwin, but other constants are also missing, so not sure how much relevant that is:
# github.com/insomniacslk/dhcp/dhcpv4/nclient4
dhcpv4/nclient4/conn_unix.go:42:59: undefined: unix.ETH_P_IP
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@Natolumin do you want me to simplify and just add CLOEXEC directly?
Go runtime adds
CLOEXECflags automatically, but when using raw syscalls, we have to do it manually.Without this flag, file descriptors leak to the child processes.