cmd/ipfs/util max fd tests don't work on MacOS

[rob-deutsch]

Version information:

go-ipfs version: 0.4.18-dev-
Repo version: 7
System version: amd64/darwin
Golang version: go1.10.3

Type:

Bug

Description:

$ go test
--- FAIL: TestManageInvalidNFds (0.00s)
        ulimit_test.go:25: Testing file descriptor invalidity
        ulimit_test.go:45: ManageFdLimit should return an error
Successfully raised file descriptor limit to 9223372036854767616.
FAIL
exit status 1
FAIL    github.com/ipfs/go-ipfs/cmd/ipfs/util   0.023s
$

This test can be found here.

This test is trying to set the FD limit higher than your OS's maximum allowed. The problem is that on MacOS this maximum allowed is at the maximum int64 value (i.e. unlimited), and we're experiencing integer wrap around.

Solution:

I am working on a fix now. The fix is based on changing the util code to use uint64 instead of int64, and adding some error conditions to the FreeBSD code.

PR incoming.