From 5e1909a20eaafad587d58acdfe66aa5672bc83b9 Mon Sep 17 00:00:00 2001
From: Nuno Cruces <ncruces@users.noreply.github.com>
Date: Mon, 24 Feb 2025 12:25:19 +0000
Subject: [PATCH] Issue #230.

---
 vfs/const.go      |  3 +++
 vfs/file.go       | 21 +++++++++++++++++----
 vfs/os_std_rw.go  | 13 +++++++++++++
 vfs/os_unix.go    | 22 ++++++++++++++++++++++
 vfs/os_windows.go | 17 +++++++++++++++++
 5 files changed, 72 insertions(+), 4 deletions(-)
 create mode 100644 vfs/os_std_rw.go

diff --git a/vfs/const.go b/vfs/const.go
index dc3b0db..b789d12 100644
--- a/vfs/const.go
+++ b/vfs/const.go
@@ -31,6 +31,7 @@ const (
 	_READONLY                _ErrorCode = util.READONLY
 	_IOERR                   _ErrorCode = util.IOERR
 	_NOTFOUND                _ErrorCode = util.NOTFOUND
+	_FULL                    _ErrorCode = util.FULL
 	_CANTOPEN                _ErrorCode = util.CANTOPEN
 	_IOERR_READ              _ErrorCode = util.IOERR_READ
 	_IOERR_SHORT_READ        _ErrorCode = util.IOERR_SHORT_READ
@@ -57,10 +58,12 @@ const (
 	_IOERR_COMMIT_ATOMIC     _ErrorCode = util.IOERR_COMMIT_ATOMIC
 	_IOERR_ROLLBACK_ATOMIC   _ErrorCode = util.IOERR_ROLLBACK_ATOMIC
 	_IOERR_DATA              _ErrorCode = util.IOERR_DATA
+	_IOERR_CORRUPTFS         _ErrorCode = util.IOERR_CORRUPTFS
 	_BUSY_SNAPSHOT           _ErrorCode = util.BUSY_SNAPSHOT
 	_CANTOPEN_FULLPATH       _ErrorCode = util.CANTOPEN_FULLPATH
 	_CANTOPEN_ISDIR          _ErrorCode = util.CANTOPEN_ISDIR
 	_READONLY_CANTINIT       _ErrorCode = util.READONLY_CANTINIT
+	_READONLY_DIRECTORY      _ErrorCode = util.READONLY_DIRECTORY
 	_OK_SYMLINK              _ErrorCode = util.OK_SYMLINK
 )
 
diff --git a/vfs/file.go b/vfs/file.go
index bc90555..83f9af3 100644
--- a/vfs/file.go
+++ b/vfs/file.go
@@ -88,6 +88,9 @@ func (vfsOS) OpenFilename(name *Filename, flags OpenFlag) (File, OpenFlag, error
 		oflags |= os.O_RDWR
 	}
 
+	isCreate := flags&(OPEN_CREATE) != 0
+	isJournl := flags&(OPEN_MAIN_JOURNAL|OPEN_SUPER_JOURNAL|OPEN_WAL) != 0
+
 	var err error
 	var f *os.File
 	if name == nil {
@@ -102,6 +105,10 @@ func (vfsOS) OpenFilename(name *Filename, flags OpenFlag) (File, OpenFlag, error
 		if errors.Is(err, syscall.EISDIR) {
 			return nil, flags, _CANTOPEN_ISDIR
 		}
+		if isCreate && isJournl && errors.Is(err, fs.ErrPermission) &&
+			osAccess(name.String(), ACCESS_EXISTS) != nil {
+			return nil, flags, _READONLY_DIRECTORY
+		}
 		return nil, flags, err
 	}
 
@@ -119,10 +126,8 @@ func (vfsOS) OpenFilename(name *Filename, flags OpenFlag) (File, OpenFlag, error
 		File:     f,
 		psow:     true,
 		readOnly: flags&OPEN_READONLY != 0,
-		syncDir: canSyncDirs &&
-			flags&(OPEN_MAIN_JOURNAL|OPEN_SUPER_JOURNAL|OPEN_WAL) != 0 &&
-			flags&(OPEN_CREATE) != 0,
-		shm: NewSharedMemory(name.String()+"-shm", flags),
+		syncDir:  canSyncDirs && isCreate && isJournl,
+		shm:      NewSharedMemory(name.String()+"-shm", flags),
 	}
 	return &file, flags, nil
 }
@@ -154,6 +159,14 @@ func (f *vfsFile) Close() error {
 	return f.File.Close()
 }
 
+func (f *vfsFile) ReadAt(p []byte, off int64) (n int, err error) {
+	return osReadAt(f.File, p, off)
+}
+
+func (f *vfsFile) WriteAt(p []byte, off int64) (n int, err error) {
+	return osWriteAt(f.File, p, off)
+}
+
 func (f *vfsFile) Sync(flags SyncFlag) error {
 	dataonly := (flags & SYNC_DATAONLY) != 0
 	fullsync := (flags & 0x0f) == SYNC_FULL
diff --git a/vfs/os_std_rw.go b/vfs/os_std_rw.go
new file mode 100644
index 0000000..40a5f27
--- /dev/null
+++ b/vfs/os_std_rw.go
@@ -0,0 +1,13 @@
+//go:build !unix && (!windows || sqlite3_dotlk)
+
+package vfs
+
+import "os"
+
+func osReadAt(file *os.File, p []byte, off int64) (int, error) {
+	return file.ReadAt(p, off)
+}
+
+func osWriteAt(file *os.File, p []byte, off int64) (int, error) {
+	return file.WriteAt(p, off)
+}
diff --git a/vfs/os_unix.go b/vfs/os_unix.go
index c4f9ba8..9f42b5f 100644
--- a/vfs/os_unix.go
+++ b/vfs/os_unix.go
@@ -25,6 +25,28 @@ func osAccess(path string, flags AccessFlag) error {
 	return unix.Access(path, access)
 }
 
+func osReadAt(file *os.File, p []byte, off int64) (int, error) {
+	n, err := file.ReadAt(p, off)
+	if errno, ok := err.(unix.Errno); ok {
+		switch errno {
+		case
+			unix.ERANGE,
+			unix.EIO,
+			unix.ENXIO:
+			return n, _IOERR_CORRUPTFS
+		}
+	}
+	return n, err
+}
+
+func osWriteAt(file *os.File, p []byte, off int64) (int, error) {
+	n, err := file.WriteAt(p, off)
+	if errno, ok := err.(unix.Errno); ok && errno == unix.ENOSPC {
+		return n, _FULL
+	}
+	return n, err
+}
+
 func osSetMode(file *os.File, modeof string) error {
 	fi, err := os.Stat(modeof)
 	if err != nil {
diff --git a/vfs/os_windows.go b/vfs/os_windows.go
index 0398f47..ecce3cf 100644
--- a/vfs/os_windows.go
+++ b/vfs/os_windows.go
@@ -9,6 +9,23 @@ import (
 	"golang.org/x/sys/windows"
 )
 
+func osReadAt(file *os.File, p []byte, off int64) (int, error) {
+	return file.ReadAt(p, off)
+}
+
+func osWriteAt(file *os.File, p []byte, off int64) (int, error) {
+	n, err := file.WriteAt(p, off)
+	if errno, ok := err.(windows.Errno); ok {
+		switch errno {
+		case
+			windows.ERROR_HANDLE_DISK_FULL,
+			windows.ERROR_DISK_FULL:
+			return n, _FULL
+		}
+	}
+	return n, err
+}
+
 func osGetSharedLock(file *os.File) _ErrorCode {
 	// Acquire the PENDING lock temporarily before acquiring a new SHARED lock.
 	rc := osReadLock(file, _PENDING_BYTE, 1, 0)