From 2750defb63a94051f2aad56e767944a3acef5cd6 Mon Sep 17 00:00:00 2001
From: Dominic Breuker <dominic.breuker@gmail.com>
Date: Mon, 26 Feb 2018 07:41:28 +0100
Subject: [PATCH] try some more tsting

---
 cmd/root.go                                   |  6 +-
 internal/{inotify => fswatcher}/event.go      |  9 +--
 internal/{inotify => fswatcher}/inotify.go    |  2 +-
 internal/fswatcher/inotify/inotify.go         | 67 +++++++++++++++++++
 internal/fswatcher/inotify/inotify_test.go    | 49 ++++++++++++++
 internal/fswatcher/inotify/sys/syscalls.go    | 36 ++++++++++
 .../fswatcher/inotify/sys/syscalls_test.go    | 45 +++++++++++++
 internal/fswatcher/inotify/watcher.go         | 30 +++++++++
 internal/{inotify => fswatcher}/observer.go   |  7 +-
 internal/{inotify => fswatcher}/setup.go      | 16 +++--
 .../walker/testdata/f11.txt                   |  0
 .../walker/testdata/f12.txt                   |  0
 .../walker/testdata/subdir/f21.txt            |  0
 .../walker/testdata/subdir/subsubdir/f31.txt  |  0
 .../{inotify => fswatcher}/walker/walker.go   |  9 +--
 .../walker/walker_test.go                     | 12 ++--
 internal/{inotify => fswatcher}/watcher.go    |  2 +-
 17 files changed, 262 insertions(+), 28 deletions(-)
 rename internal/{inotify => fswatcher}/event.go (90%)
 rename internal/{inotify => fswatcher}/inotify.go (98%)
 create mode 100644 internal/fswatcher/inotify/inotify.go
 create mode 100644 internal/fswatcher/inotify/inotify_test.go
 create mode 100644 internal/fswatcher/inotify/sys/syscalls.go
 create mode 100644 internal/fswatcher/inotify/sys/syscalls_test.go
 create mode 100644 internal/fswatcher/inotify/watcher.go
 rename internal/{inotify => fswatcher}/observer.go (58%)
 rename internal/{inotify => fswatcher}/setup.go (69%)
 rename internal/{inotify => fswatcher}/walker/testdata/f11.txt (100%)
 rename internal/{inotify => fswatcher}/walker/testdata/f12.txt (100%)
 rename internal/{inotify => fswatcher}/walker/testdata/subdir/f21.txt (100%)
 rename internal/{inotify => fswatcher}/walker/testdata/subdir/subsubdir/f31.txt (100%)
 rename internal/{inotify => fswatcher}/walker/walker.go (77%)
 rename internal/{inotify => fswatcher}/walker/walker_test.go (87%)
 rename internal/{inotify => fswatcher}/watcher.go (97%)

diff --git a/cmd/root.go b/cmd/root.go
index 27d0e29..78d26bc 100644
--- a/cmd/root.go
+++ b/cmd/root.go
@@ -9,7 +9,7 @@ import (
 	"syscall"
 
 	"github.com/dominicbreuker/pspy/internal/config"
-	"github.com/dominicbreuker/pspy/internal/inotify"
+	"github.com/dominicbreuker/pspy/internal/fswatcher"
 	"github.com/dominicbreuker/pspy/internal/logging"
 	"github.com/dominicbreuker/pspy/internal/process"
 	"github.com/dominicbreuker/pspy/internal/pspy"
@@ -74,9 +74,9 @@ func root(cmd *cobra.Command, args []string) {
 		LogPS: logPS,
 		LogFS: logFS,
 	}
-	iw, err := inotify.NewInotifyWatcher()
+	iw, err := fswatcher.NewInotifyWatcher()
 	if err != nil {
-		logger.Errorf("Can't initialize inotify: %v", err)
+		logger.Errorf("Can't initialize fswatcher: %v", err)
 		os.Exit(1)
 	}
 	defer iw.Close()
diff --git a/internal/inotify/event.go b/internal/fswatcher/event.go
similarity index 90%
rename from internal/inotify/event.go
rename to internal/fswatcher/event.go
index 4599156..0cfb601 100644
--- a/internal/inotify/event.go
+++ b/internal/fswatcher/event.go
@@ -1,4 +1,4 @@
-package inotify
+package fswatcher
 
 import (
 	"bytes"
@@ -6,6 +6,7 @@ import (
 	"strconv"
 	"unsafe"
 
+	"github.com/dominicbreuker/pspy/internal/fswatcher/inotify"
 	"golang.org/x/sys/unix"
 )
 
@@ -35,7 +36,7 @@ var InotifyEvents = map[uint32]string{
 	(unix.IN_OPEN | unix.IN_ISDIR):          "OPEN DIR",
 }
 
-func parseEvents(i *Inotify, dataCh chan []byte, eventCh chan string, errCh chan error) {
+func parseEvents(i *inotify.Inotify, dataCh chan []byte, eventCh chan string, errCh chan error) {
 	for buf := range dataCh {
 		n := len(buf)
 		if n < unix.SizeofInotifyEvent {
@@ -49,12 +50,12 @@ func parseEvents(i *Inotify, dataCh chan []byte, eventCh chan string, errCh chan
 			sys := (*unix.InotifyEvent)(unsafe.Pointer(&buf[ptr]))
 			ptr += unix.SizeofInotifyEvent
 
-			watcher, ok := i.watchers[int(sys.Wd)]
+			watcher, ok := i.Watchers[int(sys.Wd)]
 			if !ok {
 				errCh <- fmt.Errorf("Inotify event parser: unknown watcher ID: %d", sys.Wd)
 				continue
 			}
-			name = watcher.dir + "/"
+			name = watcher.Dir + "/"
 			if sys.Len > 0 && len(buf) >= int(ptr+sys.Len) {
 				name += string(bytes.TrimRight(buf[ptr:ptr+sys.Len], "\x00"))
 				ptr += sys.Len
diff --git a/internal/inotify/inotify.go b/internal/fswatcher/inotify.go
similarity index 98%
rename from internal/inotify/inotify.go
rename to internal/fswatcher/inotify.go
index 990feb6..432d25f 100644
--- a/internal/inotify/inotify.go
+++ b/internal/fswatcher/inotify.go
@@ -1,4 +1,4 @@
-package inotify
+package fswatcher
 
 import (
 	"fmt"
diff --git a/internal/fswatcher/inotify/inotify.go b/internal/fswatcher/inotify/inotify.go
new file mode 100644
index 0000000..b5bf502
--- /dev/null
+++ b/internal/fswatcher/inotify/inotify.go
@@ -0,0 +1,67 @@
+package inotify
+
+import (
+	"fmt"
+)
+
+type InotifySyscalls interface {
+	Init() (int, error)
+	AddWatch(int, string) (int, error)
+	Close(int) error
+}
+
+type Inotify struct {
+	FD       int
+	Watchers map[int]*Watcher
+	sys      InotifySyscalls
+}
+
+func NewInotify(isys InotifySyscalls) (*Inotify, error) {
+	fd, err := isys.Init()
+	if err != nil {
+		return nil, fmt.Errorf("initializing inotify: %v", err)
+	}
+
+	i := &Inotify{
+		FD:       fd,
+		Watchers: make(map[int]*Watcher),
+		sys:      isys,
+	}
+
+	return i, nil
+}
+
+func (i *Inotify) Watch(dir string) error {
+	wd, err := i.sys.AddWatch(i.FD, dir)
+	if err != nil {
+		return fmt.Errorf("adding watcher on %s: %v", dir, err)
+	}
+	i.Watchers[wd] = &Watcher{
+		WD:  wd,
+		Dir: dir,
+	}
+	return nil
+}
+
+func (i *Inotify) Close() error {
+	if err := i.sys.Close(i.FD); err != nil {
+		return fmt.Errorf("closing inotify file descriptor: %v", err)
+	}
+	return nil
+}
+
+func (i *Inotify) NumWatchers() int {
+	return len(i.Watchers)
+}
+
+func (i *Inotify) String() string {
+	if len(i.Watchers) < 20 {
+		dirs := make([]string, 0)
+		for _, w := range i.Watchers {
+			dirs = append(dirs, w.Dir)
+		}
+		return fmt.Sprintf("Watching: %v", dirs)
+	} else {
+		return fmt.Sprintf("Watching %d directories", len(i.Watchers))
+	}
+}
diff --git a/internal/fswatcher/inotify/inotify_test.go b/internal/fswatcher/inotify/inotify_test.go
new file mode 100644
index 0000000..dd253cc
--- /dev/null
+++ b/internal/fswatcher/inotify/inotify_test.go
@@ -0,0 +1,49 @@
+package inotify
+
+import (
+	"errors"
+	"testing"
+)
+
+func TestNewInotify(t *testing.T) {
+	mis := &MockInotifySyscalls{fd: 1}
+
+	i, err := NewInotify(mis)
+	if err != nil {
+		t.Fatalf("Unexpected error")
+	}
+	if i.FD != mis.fd {
+		t.Fatalf("Did not set FD of inotify object")
+	}
+}
+
+func TestNewInotifyError(t *testing.T) {
+	mis := &MockInotifySyscalls{fd: -1}
+
+	_, err := NewInotify(mis)
+	if err == nil || err.Error() != "initializing inotify: syscall error" {
+		t.Fatalf("Expected syscall error but did not get: %v", err)
+	}
+}
+
+// mock
+
+type MockInotifySyscalls struct {
+	fd int
+}
+
+func (mis *MockInotifySyscalls) Init() (int, error) {
+	if mis.fd >= 0 {
+		return mis.fd, nil
+	} else {
+		return -1, errors.New("syscall error")
+	}
+}
+
+func (mis *MockInotifySyscalls) AddWatch(fd int, dir string) (int, error) {
+	return 2, nil
+}
+
+func (mis *MockInotifySyscalls) Close(fd int) error {
+	return nil
+}
diff --git a/internal/fswatcher/inotify/sys/syscalls.go b/internal/fswatcher/inotify/sys/syscalls.go
new file mode 100644
index 0000000..24f89ba
--- /dev/null
+++ b/internal/fswatcher/inotify/sys/syscalls.go
@@ -0,0 +1,36 @@
+// +build linux
+
+package sys
+
+import (
+	"fmt"
+
+	"golang.org/x/sys/unix"
+)
+
+const events = unix.IN_ALL_EVENTS
+
+type InotifySyscallsUNIX struct{}
+
+func (isu *InotifySyscallsUNIX) Init() (int, error) {
+	fd, errno := unix.InotifyInit1(unix.IN_CLOEXEC)
+	if fd < 0 {
+		return fd, fmt.Errorf("errno: %d", errno)
+	}
+	return fd, nil
+}
+
+func (isu *InotifySyscallsUNIX) AddWatch(fd int, dir string) (int, error) {
+	wd, errno := unix.InotifyAddWatch(fd, dir, events)
+	if wd < 0 {
+		return wd, fmt.Errorf("errno: %d", errno)
+	}
+	return wd, nil
+}
+
+func (isu *InotifySyscallsUNIX) Close(fd int) error {
+	if err := unix.Close(fd); err != nil {
+		return err
+	}
+	return nil
+}
diff --git a/internal/fswatcher/inotify/sys/syscalls_test.go b/internal/fswatcher/inotify/sys/syscalls_test.go
new file mode 100644
index 0000000..aadda01
--- /dev/null
+++ b/internal/fswatcher/inotify/sys/syscalls_test.go
@@ -0,0 +1,45 @@
+// +build linux
+
+package sys
+
+import (
+	"testing"
+)
+
+func TestSyscalls(t *testing.T) {
+	is := &InotifySyscallsUNIX{}
+
+	fd, err := is.Init()
+	if err != nil {
+		t.Fatalf("Unexpected error for inotify init: %v", err)
+	}
+
+	_, err = is.AddWatch(fd, "testdata")
+	if err != nil {
+		t.Fatalf("Unexpected error adding watch to dir 'testdata': %v", err)
+	}
+
+	err = is.Close(fd)
+	if err != nil {
+		t.Fatalf("Unexpected error closing inotify: %v", err)
+	}
+}
+
+func TestSyscallsError(t *testing.T) {
+	is := &InotifySyscallsUNIX{}
+
+	fd, err := is.Init()
+	if err != nil {
+		t.Fatalf("Unexpected error for inotify init: %v", err)
+	}
+
+	_, err = is.AddWatch(fd, "non-existing-dir")
+	if err == nil || err.Error() != "errno: 2" {
+		t.Fatalf("Expected errno 2 for non-existing-dir but got: %v", err)
+	}
+
+	err = is.Close(fd)
+	if err != nil {
+		t.Fatalf("Unexpected error closing inotify: %v", err)
+	}
+}
diff --git a/internal/fswatcher/inotify/watcher.go b/internal/fswatcher/inotify/watcher.go
new file mode 100644
index 0000000..1ce2795
--- /dev/null
+++ b/internal/fswatcher/inotify/watcher.go
@@ -0,0 +1,30 @@
+package inotify
+
+import (
+	"fmt"
+	"io/ioutil"
+	"strconv"
+	"strings"
+)
+
+const maximumWatchersFile = "/proc/sys/fs/inotify/max_user_watches"
+
+type Watcher struct {
+	WD  int
+	Dir string
+}
+
+func GetLimit() (int, error) {
+	b, err := ioutil.ReadFile(maximumWatchersFile)
+	if err != nil {
+		return 0, fmt.Errorf("reading from %s: %v", maximumWatchersFile, err)
+	}
+
+	s := strings.TrimSpace(string(b))
+	m, err := strconv.Atoi(s)
+	if err != nil {
+		return 0, fmt.Errorf("converting to integer: %v", err)
+	}
+
+	return m, nil
+}
diff --git a/internal/inotify/observer.go b/internal/fswatcher/observer.go
similarity index 58%
rename from internal/inotify/observer.go
rename to internal/fswatcher/observer.go
index ea5d574..3276359 100644
--- a/internal/inotify/observer.go
+++ b/internal/fswatcher/observer.go
@@ -1,16 +1,17 @@
-package inotify
+package fswatcher
 
 import (
 	"fmt"
 
+	"github.com/dominicbreuker/pspy/internal/fswatcher/inotify"
 	"golang.org/x/sys/unix"
 )
 
-func Observe(i *Inotify, triggerCh chan struct{}, dataCh chan []byte, errCh chan error) {
+func Observe(i *inotify.Inotify, triggerCh chan struct{}, dataCh chan []byte, errCh chan error) {
 	buf := make([]byte, 5*unix.SizeofInotifyEvent)
 
 	for {
-		n, errno := unix.Read(i.fd, buf)
+		n, errno := unix.Read(i.FD, buf)
 		if n == -1 {
 			errCh <- fmt.Errorf("reading from inotify fd: errno: %d", errno)
 			return
diff --git a/internal/inotify/setup.go b/internal/fswatcher/setup.go
similarity index 69%
rename from internal/inotify/setup.go
rename to internal/fswatcher/setup.go
index 3c94e8e..4c1379e 100644
--- a/internal/inotify/setup.go
+++ b/internal/fswatcher/setup.go
@@ -1,13 +1,15 @@
-package inotify
+package fswatcher
 
 import (
 	"fmt"
 
-	"github.com/dominicbreuker/pspy/internal/inotify/walker"
+	"github.com/dominicbreuker/pspy/internal/fswatcher/inotify"
+	isys "github.com/dominicbreuker/pspy/internal/fswatcher/inotify/sys"
+	"github.com/dominicbreuker/pspy/internal/fswatcher/walker"
 )
 
 type InotifyWatcher struct {
-	i *Inotify
+	i *inotify.Inotify
 }
 
 func (iw *InotifyWatcher) Close() {
@@ -15,7 +17,7 @@ func (iw *InotifyWatcher) Close() {
 }
 
 func NewInotifyWatcher() (*InotifyWatcher, error) {
-	i, err := NewInotify()
+	i, err := inotify.NewInotify(&isys.InotifySyscallsUNIX{})
 	if err != nil {
 		return nil, fmt.Errorf("setting up inotify: %v", err)
 	}
@@ -48,8 +50,8 @@ func (iw *InotifyWatcher) Setup(rdirs, dirs []string, errCh chan error) (chan st
 	return triggerCh, eventCh, nil
 }
 
-func addWatchers(dir string, depth int, i *Inotify, maxWatchers int, errCh chan error) {
-	dirCh, doneCh := walker.Walk(dir, depth, errCh)
+func addWatchers(dir string, depth int, i *inotify.Inotify, maxWatchers int, errCh chan error) {
+	dirCh, walkErrCh, doneCh := walker.Walk(dir, depth)
 loop:
 	for {
 		if maxWatchers > 0 && i.NumWatchers() >= maxWatchers {
@@ -57,6 +59,8 @@ loop:
 			break loop
 		}
 		select {
+		case err := <-walkErrCh:
+			errCh <- fmt.Errorf("adding inotift watchers: %v", err)
 		case dir, ok := <-dirCh:
 			if !ok {
 				break loop
diff --git a/internal/inotify/walker/testdata/f11.txt b/internal/fswatcher/walker/testdata/f11.txt
similarity index 100%
rename from internal/inotify/walker/testdata/f11.txt
rename to internal/fswatcher/walker/testdata/f11.txt
diff --git a/internal/inotify/walker/testdata/f12.txt b/internal/fswatcher/walker/testdata/f12.txt
similarity index 100%
rename from internal/inotify/walker/testdata/f12.txt
rename to internal/fswatcher/walker/testdata/f12.txt
diff --git a/internal/inotify/walker/testdata/subdir/f21.txt b/internal/fswatcher/walker/testdata/subdir/f21.txt
similarity index 100%
rename from internal/inotify/walker/testdata/subdir/f21.txt
rename to internal/fswatcher/walker/testdata/subdir/f21.txt
diff --git a/internal/inotify/walker/testdata/subdir/subsubdir/f31.txt b/internal/fswatcher/walker/testdata/subdir/subsubdir/f31.txt
similarity index 100%
rename from internal/inotify/walker/testdata/subdir/subsubdir/f31.txt
rename to internal/fswatcher/walker/testdata/subdir/subsubdir/f31.txt
diff --git a/internal/inotify/walker/walker.go b/internal/fswatcher/walker/walker.go
similarity index 77%
rename from internal/inotify/walker/walker.go
rename to internal/fswatcher/walker/walker.go
index 8e85832..93128f2 100644
--- a/internal/inotify/walker/walker.go
+++ b/internal/fswatcher/walker/walker.go
@@ -9,24 +9,25 @@ import (
 
 const maxInt = int(^uint(0) >> 1)
 
-func Walk(root string, depth int, errCh chan error) (dirCh chan string, doneCh chan struct{}) {
+func Walk(root string, depth int) (dirCh chan string, errCh chan error, doneCh chan struct{}) {
 	if depth < 0 {
 		depth = maxInt
 	}
 	dirCh = make(chan string)
+	errCh = make(chan error)
 	doneCh = make(chan struct{})
 
 	go func() {
+		defer close(dirCh)
 		descent(root, depth-1, dirCh, errCh, doneCh)
-		close(dirCh)
 	}()
-	return dirCh, doneCh
+	return dirCh, errCh, doneCh
 }
 
 func descent(dir string, depth int, dirCh chan string, errCh chan error, doneCh chan struct{}) {
 	_, err := os.Stat(dir)
 	if err != nil {
-		errCh <- fmt.Errorf("Can't walk directory %s: %v", dir, err)
+		errCh <- fmt.Errorf("visiting %s: %v", dir, err)
 		return
 	}
 	select {
diff --git a/internal/inotify/walker/walker_test.go b/internal/fswatcher/walker/walker_test.go
similarity index 87%
rename from internal/inotify/walker/walker_test.go
rename to internal/fswatcher/walker/walker_test.go
index 974c2c0..76419a2 100644
--- a/internal/inotify/walker/walker_test.go
+++ b/internal/fswatcher/walker/walker_test.go
@@ -35,12 +35,12 @@ func TestWalk(t *testing.T) {
 			"testdata/subdir",
 			"testdata/subdir/subsubdir",
 		}, errs: []string{}},
-		{root: "testdata/non-existing-dir", depth: 1, errCh: newErrCh(), result: []string{}, errs: []string{"Can't walk directory testdata/non-existing-dir"}},
+		{root: "testdata/non-existing-dir", depth: 1, errCh: newErrCh(), result: []string{}, errs: []string{"visiting testdata/non-existing-dir"}},
 	}
 
 	for i, tt := range tests {
-		dirCh, doneCh := Walk(tt.root, tt.depth, tt.errCh)
-		dirs, errs := getAllDirsAndErrors(dirCh, tt.errCh)
+		dirCh, errCh, doneCh := Walk(tt.root, tt.depth)
+		dirs, errs := getAllDirsAndErrors(dirCh, errCh)
 
 		if !reflect.DeepEqual(dirs, tt.result) {
 			t.Fatalf("[%d] Wrong number of dirs found: %+v", i, dirs)
@@ -59,20 +59,20 @@ func getAllDirsAndErrors(dirCh chan string, errCh chan error) ([]string, []strin
 
 	doneDirsCh := make(chan struct{})
 	go func() {
+		defer close(doneDirsCh)
+		defer close(errCh)
 		for d := range dirCh {
 			dirs = append(dirs, d)
 		}
-		close(errCh)
-		close(doneDirsCh)
 	}()
 
 	doneErrsCh := make(chan struct{})
 	go func() {
+		defer close(doneErrsCh)
 		for err := range errCh {
 			tokens := strings.SplitN(err.Error(), ":", 2)
 			errs = append(errs, tokens[0])
 		}
-		close(doneErrsCh)
 	}()
 	<-doneDirsCh
 	<-doneErrsCh
diff --git a/internal/inotify/watcher.go b/internal/fswatcher/watcher.go
similarity index 97%
rename from internal/inotify/watcher.go
rename to internal/fswatcher/watcher.go
index a055c25..c02080a 100644
--- a/internal/inotify/watcher.go
+++ b/internal/fswatcher/watcher.go
@@ -1,4 +1,4 @@
-package inotify
+package fswatcher
 
 import (
 	"fmt"