Golang和DBUS

Question

I would like to convert this Python code in Go:

#!/usr/bin/python3

import sys
import dbus

if (len(sys.argv) < 2):
    print("Usage: %s <modem> <ussd-string>" % (sys.argv[0]))
    sys.exit(1)

bus = dbus.SystemBus()
path = sys.argv[1]
ussdstring = sys.argv[2]

ussd = dbus.Interface(bus.get_object('org.ofono', path),
                      'org.ofono.SupplementaryServices')

properties = ussd.GetProperties()
state = properties["State"]

if state == "idle":
    result = ussd.Initiate(ussdstring, timeout=100)[1]
elif state == "user-response":
    result = ussd.Respond(ussdstring, timeout=100)
else:
    sys.exit(1);

properties = ussd.GetProperties()
state = properties["State"]
print('USSD RESPONSE:
', result)
print('USSD SESSION:
', state)

I made a try with the github.com/guelfey/go.dbus library:

package main

import (
    "fmt"
    "os"

    "github.com/guelfey/go.dbus"
)

func main() {
    fmt.Printf("DBUS Test.
")
    conn, err := dbus.SessionBus()
    if err != nil {
        fmt.Fprintln(os.Stderr, "Failed to connect to session bus:", err)
        os.Exit(1)
    }

    busObject := conn.Object("org.ofono", "/ril_0")
    fmt.Println("busObject:", busObject)
    var list []string
    busObject.Call("org.ofono.SupplementaryServices.Initiate", 0, "#101#").Store(&list)
    fmt.Println("list:", list)
    for _, v := range list {
        fmt.Println(v)
    }
}

But I got the following response:

DBUS Test.
Failed to connect to session bus: user: Current not implemented on linux/arm

Do you know how to use this DBUS library? Is this library the best one for go on ARM7?

Thank you

Answer 1

This particular problem is right in the error message:

... user: Current not implemented on linux/arm"

user.Current is only called for auth, so if you supply your own Auth method it won't call user.Current.

It looks like you'll have to create your own conn though, instead of using the global sessionBus. (see the source of SessionBus and Conn.Auth for more details)

conn, err := dbusSessionBusPrivate()
if err != nil {
    return
}

auths := []dbus.Auth{dbus.AuthExternal(username), dbus.AuthCookieSha1(username, homedir)}
if err := conn.Auth(auths); err != nil {
    conn.Close()
    return
}

You could also patch go.dbus to use an alternative method for finding the username and homedir for arm, like checking $USER and $HOME (or file an issue, or open a pull request).