install error on Solaris

[lhoward]

Similar issue to #23 on Solaris. Worked around by creating azblob/zc_mmf_solaris.go with following contents (from some searching/copy/pasting – I don't know Go).

// +build solaris

package azblob

import (
        "os"
        "syscall"
        "golang.org/x/sys/unix"
)

type mmf []byte

func newMMF(file *os.File, writable bool, offset int64, length int) (mmf, error) {
        prot, flags := unix.PROT_READ, syscall.MAP_SHARED // Assume read-only
        if writable {
                prot, flags = syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_SHARED
        }
        addr, err := unix.Mmap(int(file.Fd()), offset, length, prot, flags)
        return mmf(addr), err
}

func (m *mmf) unmap() {
        err := unix.Munmap(*m)
        *m = nil
        if err != nil {
                panic("if we are unable to unmap the memory-mapped file, there is serious concern for memory corruption")
        }
}

[zezha-msft]

Hi @lhoward, thanks for reaching out!

I've logged this item to provide support for solaris.

[lhoward]

Re-reading that patch, and with about 1% more Go knowledge than when I filed the report, it should not mix the syscall and unix packages (so, remove import syscall and s/syscall/unix/).

[petems]

I think we can just add the solaris build tag to the existing file right?

Opened a PR to do so 👍

[lhoward]

No, it's a new file that uses golang.org/x/sys/unix instead of the syscall package; at least on the version of Go I have, syscall.Mmap and syscall.Munmap are unavailable on Solaris. The version below avoids mixing the two packages.

// +build solaris

package azblob

import (
        "os"
        "golang.org/x/sys/unix"
)

type mmf []byte

func newMMF(file *os.File, writable bool, offset int64, length int) (mmf, error) {
        prot, flags := unix.PROT_READ, unix.MAP_SHARED // Assume read-only
        if writable {
                prot, flags = unix.PROT_READ|unix.PROT_WRITE, unix.MAP_SHARED
        }
        addr, err := unix.Mmap(int(file.Fd()), offset, length, prot, flags)
        return mmf(addr), err
}

func (m *mmf) unmap() {
        err := unix.Munmap(*m)
        *m = nil
        if err != nil {
                panic("if we are unable to unmap the memory-mapped file, there is serious concern for memory corruption")
        }
}

[lhoward]

(Above goes in zc_mmf_solaris.go.)

[petems]

Yep, I just realised that after the build failed. IIRC syscall is now frozen so switching to the "golang.org/x/sys/unix" makes sesnse

[jclulow]

I just hit this on an illumos system while trying to build Hugo, the static site generator. In the upcoming Go 1.13, there will be an illumos build tag. It'll imply the solaris build tag, though, so fixing this for solaris will fix it for both.

Does it make sense to just use sys/unix instead of syscall for all UNIX platforms? Can I help somehow with testing (e.g., on illumos systems) to get this over the line? Thanks.

[fazalmajid]

The problem is that for whatever reasons the Go Solaris calls for mmap and pty support, among others, are in x/sys/unix instead of syscall, even though the API interfaces are the same as on other Unices, thus creating unnecessary porting friction. There's little likelihood of this being fixed anytime soon.

[zezha-msft]

Support for Solaris has been released in v0.10.0.

[jclulow]

Thanks!