From 7ad3836ad39d22dec7213bb5f4bb7e4377b3357e Mon Sep 17 00:00:00 2001
From: Leonid Podolny <leonid@digitalocean.com>
Date: Fri, 29 Sep 2017 15:34:43 -0400
Subject: [PATCH] Implement Threads() for Linux

---
 process/process_darwin.go   |  4 ++--
 process/process_fallback.go |  2 +-
 process/process_freebsd.go  |  4 ++--
 process/process_linux.go    | 12 ++++++++----
 process/process_openbsd.go  |  4 ++--
 process/process_windows.go  |  4 ++--
 6 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/process/process_darwin.go b/process/process_darwin.go
index 7de9add..1a9ed94 100644
--- a/process/process_darwin.go
+++ b/process/process_darwin.go
@@ -268,8 +268,8 @@ func (p *Process) NumThreads() (int32, error) {
 	}
 	return int32(len(r)), nil
 }
-func (p *Process) Threads() (map[string]string, error) {
-	ret := make(map[string]string, 0)
+func (p *Process) Threads() ([]int32, error) {
+	ret := make([]int32, 0)
 	return ret, common.ErrNotImplementedError
 }
 
diff --git a/process/process_fallback.go b/process/process_fallback.go
index bf09875..7c7d71d 100644
--- a/process/process_fallback.go
+++ b/process/process_fallback.go
@@ -95,7 +95,7 @@ func (p *Process) NumFDs() (int32, error) {
 func (p *Process) NumThreads() (int32, error) {
 	return 0, common.ErrNotImplementedError
 }
-func (p *Process) Threads() (map[string]string, error) {
+func (p *Process) Threads() ([]int32, error) {
 	return nil, common.ErrNotImplementedError
 }
 func (p *Process) Times() (*cpu.TimesStat, error) {
diff --git a/process/process_freebsd.go b/process/process_freebsd.go
index 4f40e12..a6b978d 100644
--- a/process/process_freebsd.go
+++ b/process/process_freebsd.go
@@ -204,8 +204,8 @@ func (p *Process) NumThreads() (int32, error) {
 
 	return k.Numthreads, nil
 }
-func (p *Process) Threads() (map[string]string, error) {
-	ret := make(map[string]string, 0)
+func (p *Process) Threads() ([]int32, error) {
+	ret := make([]int32, 0)
 	return ret, common.ErrNotImplementedError
 }
 func (p *Process) Times() (*cpu.TimesStat, error) {
diff --git a/process/process_linux.go b/process/process_linux.go
index 65cc41b..dcf4d7a 100644
--- a/process/process_linux.go
+++ b/process/process_linux.go
@@ -293,9 +293,9 @@ func (p *Process) NumThreads() (int32, error) {
 // Threads returns a map of threads
 //
 // Notice: Not implemented yet. always returns empty map.
-func (p *Process) Threads() (map[string]string, error) {
-	ret := make(map[string]string, 0)
-	return ret, nil
+func (p *Process) Threads() ([]int32, error) {
+	taskPath := common.HostProc(strconv.Itoa(int(p.Pid)), "task")
+	return readPidsFromDir(taskPath)
 }
 
 // Times returns CPU times of the process.
@@ -991,9 +991,13 @@ func (p *Process) fillFromStat() (string, int32, *cpu.TimesStat, int64, uint32,
 
 // Pids returns a slice of process ID list which are running now.
 func Pids() ([]int32, error) {
+	return readPidsFromDir(common.HostProc())
+}
+
+func readPidsFromDir(path string) ([]int32, error) {
 	var ret []int32
 
-	d, err := os.Open(common.HostProc())
+	d, err := os.Open(path)
 	if err != nil {
 		return nil, err
 	}
diff --git a/process/process_openbsd.go b/process/process_openbsd.go
index 3ca3857..b8365d5 100644
--- a/process/process_openbsd.go
+++ b/process/process_openbsd.go
@@ -194,8 +194,8 @@ func (p *Process) NumThreads() (int32, error) {
 	/* not supported, just return 1 */
 	return 1, nil
 }
-func (p *Process) Threads() (map[string]string, error) {
-	ret := make(map[string]string, 0)
+func (p *Process) Threads() ([]int32, error) {
+	ret := make([]int32, 0)
 	return ret, common.ErrNotImplementedError
 }
 func (p *Process) Times() (*cpu.TimesStat, error) {
diff --git a/process/process_windows.go b/process/process_windows.go
index d94dcbc..ff55274 100644
--- a/process/process_windows.go
+++ b/process/process_windows.go
@@ -273,8 +273,8 @@ func (p *Process) NumThreads() (int32, error) {
 	}
 	return int32(dst[0].ThreadCount), nil
 }
-func (p *Process) Threads() (map[string]string, error) {
-	ret := make(map[string]string, 0)
+func (p *Process) Threads() ([]int32, error) {
+	ret := make([]int32, 0)
 	return ret, common.ErrNotImplementedError
 }
 func (p *Process) Times() (*cpu.TimesStat, error) {