command/agent/host: eliminate calling external programs

command/agent/host/darwin.go

@@ -2,53 +2,10 @@
 
 package host
 
-import (
-	"bufio"
-	"strings"
-)
-
 func network() string {
-	return call("ifconfig")
-}
-
-func resolvConf() string {
-	return call("scutil", "--dns")
+	return ""
 }
 
-func mountedPaths() (paths []string) {
-	// TODO (langmartin) diskutil list -plist physical is a better source for disks to
-	// check, but needs a little xml parsing
-	out := call("mount")
-	rd := bufio.NewReader(strings.NewReader(out))
-
-	for {
-		str, err := rd.ReadString('\n')
-		if err != nil {
-			break
-		}
-
-		// find the last ( in the line, it's the beginning of the args
-		i := len(str) - 1
-		for ; ; i-- {
-			if str[i] == '(' {
-				break
-			}
-		}
-
-		// split the args part of the string
-		args := strings.Split(str[i+1:len(str)-2], ", ")
-
-		// split the device and mountpoint
-		mnt := strings.Split(str[:i-1], " on ")
-
-		switch args[0] {
-		case "devfs", "autofs":
-			continue
-		default:
-		}
-
-		paths = append(paths, mnt[1])
-	}
-
-	return paths
+func mountedPaths() []string {
+	return []string{"/"}
 }

command/agent/host/host.go

@@ -3,17 +3,18 @@ package host
 import (
 	"fmt"
 	"os"
-	"os/exec"
 	"strings"
+
+	sockaddr "github.com/hashicorp/go-sockaddr"
 )
 
 type HostData struct {
-	OS         string
-	Network    string
-	ResolvConf string
-	Hosts      string
-	Systemd    string
-	Disk       map[string]DiskUsage
+	OS          string
+	Network     string
+	ResolvConf  string
+	Hosts       string
+	Environment map[string]string
+	Disk        map[string]DiskUsage
 }
 
 type DiskUsage struct {
@@ -36,12 +37,12 @@ func MakeHostData() (*HostData, error) {
 	}
 
 	return &HostData{
-		OS:         uname,
-		Network:    network(),
-		ResolvConf: resolvConf(),
-		Hosts:      etcHosts(),
-		Systemd:    slurp("/etc/systemd/nomad.conf"),
-		Disk:       du,
+		OS:          uname,
+		Network:     network(),
+		ResolvConf:  resolvConf(),
+		Hosts:       etcHosts(),
+		Environment: environment(),
+		Disk:        du,
 	}, nil
 }
 
@@ -66,11 +67,15 @@ func diskUsage(path string) (du DiskUsage, err error) {
 	return du, nil
 }
 
-// call executes the command line and returns stdout, ignoring errors
-func call(cmd string, args ...string) string {
-	// cmd = which(cmd)
-	out, _ := exec.Command(cmd, args...).Output()
-	return string(out)
+// environment returns the process environment in a map
+func environment() map[string]string {
+	env := make(map[string]string)
+
+	for _, e := range os.Environ() {
+		s := strings.SplitN(e, "=", 2)
+		env[s[0]] = s[1]
+	}
+	return env
 }
 
 // slurp returns the file contents as a string, ignoring errors

command/agent/host/linux.go

@@ -4,29 +4,39 @@ package host
 
 import (
 	"bufio"
+	"os"
 	"strings"
 )
 
 func network() string {
 	return call("ip", "address", "list")
 }
 
-func resolvConf() string {
-	return slurp("/etc/resolv.conf")
-}
-
 // mountedPaths produces a list of mounts
 func mountedPaths() []string {
-	out := call("findmnt", "-D", "-tnotmpfs,nodevtmpfs", "-o", "TARGET")
-	rd := bufio.NewReader(strings.NewReader(out))
+	fh := os.Open("/proc/mounts")
+	rd := bufio.NewReader(strings.NewReader(fh))
 
 	var paths []string
 	for {
 		str, err := rd.ReadString('\n')
 		if err != nil {
 			break
 		}
-		paths = append(paths, str)
+
+		ln := strings.Split(str, " ")
+		switch ln[2] {
+		case "autofs", "binfmt_misc", "cgroup", "debugfs",
+			"devpts", "devtmpfs",
+			"fusectl", "fuse.lxcfs",
+			"hugetlbfs", "mqueue",
+			"proc", "pstore", "rpc_pipefs", "securityfs",
+			"sysfs", "tmpfs", "vboxsf":
+			continue
+		default:
+		}
+
+		paths = append(paths, ln[1])
 	}
 
 	return paths

command/agent/host/unix.go

@@ -33,6 +33,10 @@ func etcHosts() string {
 	return slurp("/etc/hosts")
 }
 
+func resolvConf() string {
+	return slurp("/etc/resolv.conf")
+}
+
 func nullStr(bs []byte) string {
 	// find the null byte
 	var i int