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common/fs/fs.go

@@ -7,8 +7,8 @@ import (
 	"syscall"
 )
 
-// T is the filesystem interface type.
-type T interface {
+// Interface is the filesystem interface type.
+type Interface interface {
 	ReadDir(string) ([]os.FileInfo, error)
 	ReadFile(string) ([]byte, error)
 	Lstat(string, *syscall.Stat_t) error
@@ -19,17 +19,7 @@ type T interface {
 type realFS struct{}
 
 // FS is the way you should access the filesystem.
-var FS T = realFS{}
-
-// Mock is used to switch out the filesystem for a mock.
-func Mock(fs T) {
-	FS = fs
-}
-
-// Restore puts back the real filesystem.
-func Restore() {
-	FS = realFS{}
-}
+var fs Interface = realFS{}
 
 func (realFS) ReadDir(path string) ([]os.FileInfo, error) {
 	return ioutil.ReadDir(path)
@@ -50,3 +40,40 @@ func (realFS) Stat(path string, stat *syscall.Stat_t) error {
 func (realFS) Open(path string) (io.ReadWriteCloser, error) {
 	return os.Open(path)
 }
+
+// trampolines here to allow users to do fs.ReadDir etc
+
+// ReadDir see ioutil.ReadDir
+func ReadDir(path string) ([]os.FileInfo, error) {
+	return fs.ReadDir(path)
+}
+
+// ReadFile see ioutil.ReadFile
+func ReadFile(path string) ([]byte, error) {
+	return fs.ReadFile(path)
+}
+
+// Lstat see syscall.Lstat
+func Lstat(path string, stat *syscall.Stat_t) error {
+	return fs.Lstat(path, stat)
+}
+
+// Stat see syscall.Stat
+func Stat(path string, stat *syscall.Stat_t) error {
+	return fs.Stat(path, stat)
+}
+
+// Open see os.Open
+func Open(path string) (io.ReadWriteCloser, error) {
+	return fs.Open(path)
+}
+
+// Mock is used to switch out the filesystem for a mock.
+func Mock(mock Interface) {
+	fs = mock
+}
+
+// Restore puts back the real filesystem.
+func Restore() {
+	fs = realFS{}
+}

probe/endpoint/procspy/proc.go

@@ -34,7 +34,7 @@ func walkProcPid(buf *bytes.Buffer, walker process.Walker) (map[uint64]Proc, err
 	walker.Walk(func(p process.Process) {
 		dirName := strconv.Itoa(p.PID)
 		fdBase := filepath.Join(procRoot, dirName, "fd")
-		fds, err := fs.FS.ReadDir(fdBase)
+		fds, err := fs.ReadDir(fdBase)
 		if err != nil {
 			// Process is be gone by now, or we don't have access.
 			return
@@ -42,7 +42,7 @@ func walkProcPid(buf *bytes.Buffer, walker process.Walker) (map[uint64]Proc, err
 
 		// Read network namespace, and if we haven't seen it before,
 		// read /proc/<pid>/net/tcp
-		err = fs.FS.Lstat(filepath.Join(procRoot, dirName, "/ns/net"), &statT)
+		err = fs.Lstat(filepath.Join(procRoot, dirName, "/ns/net"), &statT)
 		if err != nil {
 			return
 		}
@@ -55,7 +55,7 @@ func walkProcPid(buf *bytes.Buffer, walker process.Walker) (map[uint64]Proc, err
 
 		for _, fd := range fds {
 			// Direct use of syscall.Stat() to save garbage.
-			err = fs.FS.Stat(filepath.Join(fdBase, fd.Name()), &statT)
+			err = fs.Stat(filepath.Join(fdBase, fd.Name()), &statT)
 			if err != nil {
 				continue
 			}
@@ -79,7 +79,7 @@ func walkProcPid(buf *bytes.Buffer, walker process.Walker) (map[uint64]Proc, err
 // be overwritten for benchmarks. That's bad practice and we should change it
 // to be a dependency.
 var readFile = func(filename string, buf *bytes.Buffer) error {
-	f, err := fs.FS.Open(filename)
+	f, err := fs.Open(filename)
 	if err != nil {
 		return err
 	}

probe/process/walker_linux.go

@@ -23,7 +23,7 @@ func NewWalker(procRoot string) Walker {
 // passes one-by-one to the supplied function. Walk is only made public
 // so that is can be tested.
 func (w *walker) Walk(f func(Process)) error {
-	dirEntries, err := fs.FS.ReadDir(w.procRoot)
+	dirEntries, err := fs.ReadDir(w.procRoot)
 	if err != nil {
 		return err
 	}
@@ -35,7 +35,7 @@ func (w *walker) Walk(f func(Process)) error {
 			continue
 		}
 
-		stat, err := fs.FS.ReadFile(path.Join(w.procRoot, filename, "stat"))
+		stat, err := fs.ReadFile(path.Join(w.procRoot, filename, "stat"))
 		if err != nil {
 			continue
 		}
@@ -51,13 +51,13 @@ func (w *walker) Walk(f func(Process)) error {
 		}
 
 		cmdline := ""
-		if cmdlineBuf, err := fs.FS.ReadFile(path.Join(w.procRoot, filename, "cmdline")); err == nil {
+		if cmdlineBuf, err := fs.ReadFile(path.Join(w.procRoot, filename, "cmdline")); err == nil {
 			cmdlineBuf = bytes.Replace(cmdlineBuf, []byte{'\000'}, []byte{' '}, -1)
 			cmdline = string(cmdlineBuf)
 		}
 
 		comm := "(unknown)"
-		if commBuf, err := fs.FS.ReadFile(path.Join(w.procRoot, filename, "comm")); err == nil {
+		if commBuf, err := fs.ReadFile(path.Join(w.procRoot, filename, "comm")); err == nil {
 			comm = strings.TrimSpace(string(commBuf))
 		}
 

test/fs/fs.go

@@ -33,7 +33,7 @@ type File struct {
 // Entry is an entry in the mock filesystem
 type Entry interface {
 	os.FileInfo
-	fs.T
+	fs.Interface
 }
 
 // Dir creates a new directory with the given entries.