X-Git-Url: https://ruderich.org/simon/gitweb/?a=blobdiff_plain;f=file.go;h=1d102a4e09d0152547485da18c051d727d9510b2;hb=278c50be3d8a8c433aa862d602492112b9f26a67;hp=e06a9bce335ccc4e4444e5f8ea9502d27df09eba;hpb=44a325a9bea5f53c6489cecb3691709306a1814c;p=nsscash%2Fnsscash.git

diff --git a/file.go b/file.go
index e06a9bc..1d102a4 100644
--- a/file.go
+++ b/file.go
@@ -1,6 +1,6 @@
 // Download and write files atomically to the file system
 
-// Copyright (C) 2019  Simon Ruderich
+// Copyright (C) 2019-2021  Simon Ruderich
 //
 // This program is free software: you can redistribute it and/or modify
 // it under the terms of the GNU Affero General Public License as published by
@@ -30,6 +30,7 @@ import (
 	"syscall"
 	"time"
 
+	"github.com/google/renameio"
 	"github.com/pkg/errors"
 )
 
@@ -89,12 +90,17 @@ func fetchFile(file *File, state *State) error {
 		t = zero // force download
 	}
 
+	oldT := t
 	status, body, err := fetchIfModified(file.Url,
 		file.Username, file.Password, file.CA, &t)
 	if err != nil {
 		return err
 	}
 	if status == http.StatusNotModified {
+		if oldT.IsZero() {
+			return fmt.Errorf("status code 304 " +
+				"but did not send If-Modified-Since")
+		}
 		log.Printf("%q -> %q: not modified", file.Url, file.Path)
 		return nil
 	}
@@ -159,18 +165,11 @@ func deployFile(file *File) error {
 		return fmt.Errorf("refusing to write empty file")
 	}
 
-	// Write the file in an atomic fashion by creating a temporary file
-	// and renaming it over the target file
-
-	dir := filepath.Dir(file.Path)
-	name := filepath.Base(file.Path)
-
-	f, err := ioutil.TempFile(dir, "tmp-"+name+"-")
+	f, err := renameio.TempFile(filepath.Dir(file.Path), file.Path)
 	if err != nil {
 		return err
 	}
-	defer os.Remove(f.Name())
-	defer f.Close()
+	defer f.Cleanup()
 
 	// Apply permissions/user/group from the target file but remove the
 	// write permissions to discourage manual modifications, use Stat
@@ -199,9 +198,5 @@ func deployFile(file *File) error {
 	if err != nil {
 		return err
 	}
-	err = f.Sync()
-	if err != nil {
-		return err
-	}
-	return os.Rename(f.Name(), file.Path)
+	return f.CloseAtomicallyReplace()
 }