From 0d57d2b6d8c304c83f02384049cd38467a084904 Mon Sep 17 00:00:00 2001
From: Daniel Milde <daniel@milde.cz>
Date: Thu, 19 Aug 2021 22:38:33 +0200
Subject: [PATCH] check errors when closing files

---
 cmd/gdu/app/app.go      | 44 ++++++++++++++++++++++++++---------------
 pkg/device/dev_linux.go | 14 +++++++++++--
 report/export.go        |  5 ++++-
 tui/actions.go          |  6 +++++-
 4 files changed, 49 insertions(+), 20 deletions(-)

diff --git a/cmd/gdu/app/app.go b/cmd/gdu/app/app.go
index be536dfa7..3949d956c 100644
--- a/cmd/gdu/app/app.go
+++ b/cmd/gdu/app/app.go
@@ -63,36 +63,47 @@ type App struct {
 }
 
 // Run starts gdu main logic
-func (a *App) Run() error {
+func (a *App) Run() (err error) {
+	var (
+		f  *os.File
+		ui UI
+	)
+
 	if a.Flags.ShowVersion {
 		fmt.Fprintln(a.Writer, "Version:\t", build.Version)
 		fmt.Fprintln(a.Writer, "Built time:\t", build.Time)
 		fmt.Fprintln(a.Writer, "Built user:\t", build.User)
-		return nil
+		return
 	}
 
-	f, err := os.OpenFile(a.Flags.LogFile, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
+	f, err = os.OpenFile(a.Flags.LogFile, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
 	if err != nil {
-		return fmt.Errorf("opening log file: %w", err)
+		err = fmt.Errorf("opening log file: %w", err)
+		return
 	}
-	defer f.Close()
+	defer func() {
+		cerr := f.Close()
+		if err == nil {
+			err = cerr
+		}
+	}()
 	log.SetOutput(f)
 
 	path := a.getPath()
-	ui, err := a.createUI()
+	ui, err = a.createUI()
 	if err != nil {
-		return err
+		return
 	}
 
-	if err := a.setNoCross(path); err != nil {
-		return err
+	if err = a.setNoCross(path); err != nil {
+		return
 	}
 
 	ui.SetIgnoreDirPaths(a.Flags.IgnoreDirs)
 
 	if len(a.Flags.IgnoreDirPatterns) > 0 {
-		if err := ui.SetIgnoreDirPatterns(a.Flags.IgnoreDirPatterns); err != nil {
-			return err
+		if err = ui.SetIgnoreDirPatterns(a.Flags.IgnoreDirPatterns); err != nil {
+			return
 		}
 	}
 
@@ -102,11 +113,12 @@ func (a *App) Run() error {
 
 	a.setMaxProcs()
 
-	if err := a.runAction(ui, path); err != nil {
-		return err
+	if err = a.runAction(ui, path); err != nil {
+		return
 	}
 
-	return ui.StartUILoop()
+	err = ui.StartUILoop()
+	return
 }
 
 func (a *App) getPath() string {
@@ -136,7 +148,7 @@ func (a *App) createUI() (UI, error) {
 		if a.Flags.OutputFile == "-" {
 			output = os.Stdout
 		} else {
-			output, err = os.OpenFile(a.Flags.OutputFile, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
+			output, err = os.OpenFile(a.Flags.OutputFile, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
 			if err != nil {
 				return nil, fmt.Errorf("opening output file: %w", err)
 			}
@@ -197,7 +209,7 @@ func (a *App) runAction(ui UI, path string) error {
 		if a.Flags.InputFile == "-" {
 			input = os.Stdin
 		} else {
-			input, err = os.OpenFile(a.Flags.InputFile, os.O_RDONLY, 0644)
+			input, err = os.OpenFile(a.Flags.InputFile, os.O_RDONLY, 0600)
 			if err != nil {
 				return fmt.Errorf("opening input file: %w", err)
 			}
diff --git a/pkg/device/dev_linux.go b/pkg/device/dev_linux.go
index dafcd03f6..767eed3cc 100644
--- a/pkg/device/dev_linux.go
+++ b/pkg/device/dev_linux.go
@@ -2,6 +2,7 @@ package device
 
 import (
 	"bufio"
+	"fmt"
 	"io"
 	"os"
 	"strings"
@@ -22,9 +23,18 @@ func (t LinuxDevicesInfoGetter) GetMounts() (Devices, error) {
 	if err != nil {
 		return nil, err
 	}
-	defer file.Close()
 
-	return readMountsFile(file)
+	devices, err := readMountsFile(file)
+	if err != nil {
+		if cerr := file.Close(); cerr != nil {
+			return nil, fmt.Errorf("%w; %s", err, cerr)
+		}
+		return nil, err
+	}
+	if err := file.Close(); err != nil {
+		return nil, err
+	}
+	return devices, nil
 }
 
 // GetDevicesInfo returns result of GetMounts with usage info about mounted devices (by calling Statfs syscall)
diff --git a/report/export.go b/report/export.go
index f53532b28..85ad477d6 100644
--- a/report/export.go
+++ b/report/export.go
@@ -110,7 +110,10 @@ func (ui *UI) AnalyzePath(path string, _ *analyze.Dir) error {
 
 	switch f := ui.exportOutput.(type) {
 	case *os.File:
-		f.Close()
+		err = f.Close()
+		if err != nil {
+			return err
+		}
 	}
 
 	if ui.ShowProgress {
diff --git a/tui/actions.go b/tui/actions.go
index 417ff14b2..fbf301b86 100644
--- a/tui/actions.go
+++ b/tui/actions.go
@@ -262,7 +262,11 @@ func (ui *UI) showFile() *tview.TextView {
 
 	file.SetInputCapture(func(event *tcell.EventKey) *tcell.EventKey {
 		if event.Rune() == 'q' || event.Key() == tcell.KeyESC {
-			f.Close()
+			err = f.Close()
+			if err != nil {
+				ui.showErr("Error closing file", err)
+				return event
+			}
 			ui.currentDirLabel.SetText("[::b] --- " +
 				strings.TrimPrefix(ui.currentDirPath, build.RootPathPrefix) +
 				" ---").SetDynamicColors(true)