Implement free space check

Author: Enrico204

repo/repo.go

@@ -151,9 +151,9 @@ func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 			err := h.RepoHealth()
 			if err != nil {
 				if h.opt.Debug {
-					log.Println("health check error: ", err)
+					log.Println("health check error:", err)
 				}
-				w.WriteHeader(http.StatusInternalServerError)
+				h.internalServerError(w, err)
 			} else {
 				w.WriteHeader(http.StatusOK)
 			}
@@ -773,13 +773,31 @@ func (h *Handler) RepoHealth() error {
 	// Check if the repo is writable [Linux/UNIX only code]
 	pathIsWritable, err := isWritable(h.path)
 	if err != nil {
+		if h.opt.Debug {
+			log.Println("repository path check error:", err)
+		}
 		return err
 	} else if !pathIsWritable {
-		return errors.New("Repository path is not writable")
+		return errors.New("repository path is not writable")
+	}
+	if h.opt.Debug {
+		log.Println("repository path is writable")
 	}
 
-	// Check if there is free space left
-	// TODO
+	// Check if there is some free space left
+	freeBytes, err := getFreeSpace(h.path)
+	if err != nil {
+		if h.opt.Debug {
+			log.Println("free space check error:", err)
+		}
+		return err
+	}
+	if h.opt.Debug {
+		log.Println("free space in bytes:", freeBytes)
+	}
+	if freeBytes < 8*1024*1024 {
+		return errors.New("free space is too low")
+	}
 
 	return nil
 }

repo/repo_health_unix.go

@@ -1,10 +1,33 @@
+//go:build !windows
 // +build !windows
 
 package repo
 
-import "golang.org/x/sys/unix"
+import (
+	"errors"
+	"io/fs"
+	"syscall"
+
+	"golang.org/x/sys/unix"
+)
 
 func isWritable(path string) (bool, error) {
 	err := unix.Access(path, unix.W_OK)
+	var err2 syscall.Errno
+	if errors.As(err, &err2) && err2.Is(fs.ErrPermission) {
+		return false, nil
+	}
 	return err == nil, err
 }
+
+func getFreeSpace(path string) (uint64, error) {
+	var stat unix.Statfs_t
+
+	err := unix.Statfs(path, &stat)
+	if err != nil {
+		return 0, err
+	}
+
+	// Available blocks * size per block = available space in bytes
+	return stat.Bavail * uint64(stat.Bsize), nil
+}

repo/repo_health_windows.go

@@ -1,15 +1,21 @@
 package repo
 
 import (
+	"errors"
 	"syscall"
+	"unsafe"
 
 	"github.com/itchio/ox/syscallex"
 	"github.com/itchio/ox/winox"
+	"golang.org/x/sys/windows"
 )
 
 var (
 	advapi32DLL         = syscall.NewLazyDLL("advapi32.dll")
 	impersonateSelfProc = advapi32DLL.NewProc("ImpersonateSelf")
+
+	kernel32DLL             = syscall.NewLazyDLL("kernel32.dll")
+	getDiskFreeSpaceExWProc = kernel32DLL.NewProc("GetDiskFreeSpaceExW")
 )
 
 func ImpersonateSelf(impersonationLevel uint64) (bool, error) {
@@ -22,6 +28,21 @@ func ImpersonateSelf(impersonationLevel uint64) (bool, error) {
 	return syscall.Handle(r1) == 1, nil
 }
 
+func GetDiskFreeSpaceExW(path string) (int64, error) {
+	var freeBytes int64
+
+	_, _, err := getDiskFreeSpaceExWProc.Call(
+		uintptr(unsafe.Pointer(windows.StringToUTF16Ptr(path))),
+		uintptr(unsafe.Pointer(&freeBytes)),
+		0,
+		0,
+	)
+	if err != syscall.Errno(0) {
+		return 0, err
+	}
+	return freeBytes, nil
+}
+
 func isWritable(path string) (bool, error) {
 	if _, err := ImpersonateSelf(syscallex.SecurityImpersonation); err != nil {
 		return false, err
@@ -45,3 +66,11 @@ func isWritable(path string) (bool, error) {
 
 	return winox.UserHasPermission(impersonationToken, winox.RightsRead|winox.RightsWrite, path)
 }
+
+func getFreeSpace(path string) (uint64, error) {
+	freeBytes, err := GetDiskFreeSpaceExW(path)
+	if err == nil && freeBytes < 0 {
+		return 0, errors.New("free space can't be negative")
+	}
+	return uint64(freeBytes), err
+}