Fix #596 Implement process.Background and process.Foreground functions

process/process.go

@@ -146,6 +146,19 @@ func PidExistsWithContext(ctx context.Context, pid int32) (bool, error) {
 	return false, err
 }
 
+// Background returns true if the process is in background, false otherwise.
+func (p *Process) Background() (bool, error) {
+	return p.BackgroundWithContext(context.Background())
+}
+
+func (p *Process) BackgroundWithContext(ctx context.Context) (bool, error) {
+	fg, err := p.ForegroundWithContext(ctx)
+	if err != nil {
+		return false, err
+	}
+	return !fg, err
+}
+
 // If interval is 0, return difference from last call(non-blocking).
 // If interval > 0, wait interval sec and return diffrence between start and end.
 func (p *Process) Percent(interval time.Duration) (float64, error) {

process/process_darwin.go

@@ -239,6 +239,25 @@ func (p *Process) StatusWithContext(ctx context.Context) (string, error) {
 
 	return r[0][0], err
 }
+
+func (p *Process) Foreground() (bool, error) {
+	return p.ForegroundWithContext(context.Background())
+}
+
+func (p *Process) ForegroundWithContext(ctx context.Context) (bool, error) {
+	// see https://github.com/shirou/gopsutil/issues/596#issuecomment-432707831 for implementation details
+	pid := p.Pid
+	ps, err := exec.LookPath("ps")
+	if err != nil {
+		return false, err
+	}
+	out, err := invoke.CommandWithContext(ctx, ps, "-o", "stat=", "-p", string(pid))
+	if err != nil {
+		return false, err
+	}
+	return strings.IndexByte(string(out), '+') != -1, nil
+}
+
 func (p *Process) Uids() ([]int32, error) {
 	return p.UidsWithContext(context.Background())
 }

process/process_fallback.go

@@ -114,6 +114,13 @@ func (p *Process) Status() (string, error) {
 func (p *Process) StatusWithContext(ctx context.Context) (string, error) {
 	return "", common.ErrNotImplementedError
 }
+func (p *Process) Foreground() (bool, error) {
+	return p.ForegroundWithContext(context.Background())
+}
+
+func (p *Process) ForegroundWithContext() (bool, error) {
+	return false, common.ErrNotImplementedError
+}
 func (p *Process) Uids() ([]int32, error) {
 	return p.UidsWithContext(context.Background())
 }

process/process_freebsd.go

@@ -6,6 +6,7 @@ import (
 	"bytes"
 	"context"
 	"encoding/binary"
+	"os/exec"
 	"strings"
 
 	cpu "github.com/shirou/gopsutil/cpu"
@@ -168,6 +169,25 @@ func (p *Process) StatusWithContext(ctx context.Context) (string, error) {
 
 	return s, nil
 }
+
+func (p *Process) Foreground() (bool, error) {
+	return p.ForegroundWithContext(context.Background())
+}
+
+func (p *Process) ForegroundWithContext(ctx context.Context) (bool, error) {
+	// see https://github.com/shirou/gopsutil/issues/596#issuecomment-432707831 for implementation details
+	pid := p.Pid
+	ps, err := exec.LookPath("ps")
+	if err != nil {
+		return false, err
+	}
+	out, err := invoke.CommandWithContext(ctx, ps, "-o", "stat=", "-p", string(pid))
+	if err != nil {
+		return false, err
+	}
+	return strings.IndexByte(string(out), '+') != -1, nil
+}
+
 func (p *Process) Uids() ([]int32, error) {
 	return p.UidsWithContext(context.Background())
 }

process/process_linux.go

@@ -199,6 +199,28 @@ func (p *Process) StatusWithContext(ctx context.Context) (string, error) {
 	return p.status, nil
 }
 
+// Foreground returns true if the process is in foreground, false otherwise.
+func (p *Process) Foreground() (bool, error) {
+	return p.ForegroundWithContext(context.Background())
+}
+
+func (p *Process) ForegroundWithContext(ctx context.Context) (bool, error) {
+	// see https://github.com/shirou/gopsutil/issues/596#issuecomment-432707831 for implementation details
+	pid := p.Pid
+	statPath := common.HostProc(strconv.Itoa(int(pid)), "stat")
+	contents, err := ioutil.ReadFile(statPath)
+	if err != nil {
+		return false, err
+	}
+	fields := strings.Fields(string(contents))
+	if len(fields) < 8 {
+		return false, fmt.Errorf("insufficient data in %s", statPath)
+	}
+	pgid := fields[4]
+	tpgid := fields[7]
+	return pgid == tpgid, nil
+}
+
 // Uids returns user ids of the process as a slice of the int
 func (p *Process) Uids() ([]int32, error) {
 	return p.UidsWithContext(context.Background())

process/process_windows.go

@@ -250,6 +250,15 @@ func (p *Process) Status() (string, error) {
 func (p *Process) StatusWithContext(ctx context.Context) (string, error) {
 	return "", common.ErrNotImplementedError
 }
+
+func (p *Process) Foreground() (bool, error) {
+	return p.ForegroundWithContext(context.Background())
+}
+
+func (p *Process) ForegroundWithContext(ctx context.Context) (bool, error) {
+	return false, common.ErrNotImplementedError
+}
+
 func (p *Process) Username() (string, error) {
 	return p.UsernameWithContext(context.Background())
 }