func getUIDandGID()

in lib/ec2macosinit/util.go [82:150]
49 lines of code
11 McCabe index (conditional complexity)

func getUIDandGID(username string) (uid int, gid int, err error) {
	var uidstr, gidstr string
	// Preference is user.Lookup(), if it works
	u, lookuperr := user.Lookup(username)
	if lookuperr != nil {
		// user.Lookup() has failed, second try by checking the DS cache
		out, cmderr := executeCommand([]string{"dscacheutil", "-q", "user", "-a", "name", username}, "", []string{})
		if cmderr != nil {
			// dscacheutil has failed with an error
			return 0, 0, fmt.Errorf("ec2macosinit: error while looking up user %s: \n"+
				"user.Lookup() error: %s \ndscacheutil error: %s\ndscacheutil stderr: %s\n",
				username, lookuperr, cmderr, out.stderr)
		}
		// Check length of stdout - dscacheutil returns nothing if user is not found
		if len(out.stdout) > 0 { // dscacheutil has returned something
			// Command output from dscacheutil should look like:
			//   name: ec2-user
			//   password: ********
			//   uid: 501
			//   gid: 20
			//   dir: /Users/ec2-user
			//   shell: /bin/bash
			//   gecos: ec2-user
			dsSplit := strings.Split(out.stdout, "\n") // split on newline to separate uid and gid
			for _, e := range dsSplit {
				eSplit := strings.Fields(e) // split into fields to separate tag with id
				// Find UID and GID and set them
				if strings.HasPrefix(e, "uid") {
					if len(eSplit) != 2 {
						// dscacheutil has returned some sort of weird output that can't be split
						return 0, 0, fmt.Errorf("ec2macosinit: error while splitting dscacheutil uid output for user %s: %s\n"+
							"user.Lookup() error: %s \ndscacheutil error: %s\ndscacheutil stderr: %s\n",
							username, out.stdout, lookuperr, cmderr, out.stderr)
					}
					uidstr = eSplit[1]
				} else if strings.HasPrefix(e, "gid") {
					if len(eSplit) != 2 {
						// dscacheutil has returned some sort of weird output that can't be split
						return 0, 0, fmt.Errorf("ec2macosinit: error while splitting dscacheutil gid output for user %s: %s\n"+
							"user.Lookup() error: %s \ndscacheutil error: %s\ndscacheutil stderr: %s\n",
							username, out.stdout, lookuperr, cmderr, out.stderr)
					}
					gidstr = eSplit[1]
				}
			}
		} else {
			// dscacheutil has returned nothing, user is not found
			return 0, 0, fmt.Errorf("ec2macosinit: user %s not found: \n"+
				"user.Lookup() error: %s \ndscacheutil error: %s\ndscacheutil stderr: %s\n",
				username, lookuperr, cmderr, out.stderr)
		}
	} else {
		// user.Lookup() was successful, use the returned UID/GID
		uidstr = u.Uid
		gidstr = u.Gid
	}

	// Convert UID and GID to int
	uid, err = strconv.Atoi(uidstr)
	if err != nil {
		return 0, 0, fmt.Errorf("ec2macosinit: error while converting UID to int: %s\n", err)
	}
	gid, err = strconv.Atoi(gidstr)
	if err != nil {
		return 0, 0, fmt.Errorf("ec2macosinit: error while converting GID to int: %s\n", err)
	}

	return uid, gid, nil
}