From 7b68f5e7ec1cdf730ab8a5fc723eb9a7e7776a65 Mon Sep 17 00:00:00 2001
From: Son Roy Almerol <sralmerol@sgl.com>
Date: Tue, 12 Nov 2024 12:29:03 -0500
Subject: [PATCH] add unexpected eof handler

---
 internal/agent/sftp/config.go     |  3 ---
 internal/agent/sftp/eof.go        | 28 ++++++++++++++++++++++++++++
 internal/agent/sftp/filelister.go | 12 ++----------
 internal/agent/sftp/handler.go    | 11 +++++++++--
 internal/backend/mount/mount.go   |  2 +-
 5 files changed, 40 insertions(+), 16 deletions(-)
 create mode 100644 internal/agent/sftp/eof.go

diff --git a/internal/agent/sftp/config.go b/internal/agent/sftp/config.go
index f6dcc74..1f15067 100644
--- a/internal/agent/sftp/config.go
+++ b/internal/agent/sftp/config.go
@@ -37,9 +37,6 @@ func (s *SFTPConfig) GetRegistryKey() string {
 
 func InitializeSFTPConfig(svc service.Service, driveLetter string) (*SFTPConfig, error) {
 	var err error
-	if err != nil {
-		return nil, fmt.Errorf("InitializeLogger: failed to initialize logger -> %w", err)
-	}
 
 	baseKey, _, err := registry.CreateKey(registry.LOCAL_MACHINE, "Software\\PBSPlus\\Config", registry.QUERY_VALUE)
 	if err != nil {
diff --git a/internal/agent/sftp/eof.go b/internal/agent/sftp/eof.go
new file mode 100644
index 0000000..5b8b0f7
--- /dev/null
+++ b/internal/agent/sftp/eof.go
@@ -0,0 +1,28 @@
+package sftp
+
+import "io"
+
+type eofInjectingReaderAt struct {
+	file   io.ReaderAt
+	length int64
+}
+
+func NewEOFInjectingReaderAt(file io.ReaderAt, length int64) io.ReaderAt {
+	return &eofInjectingReaderAt{file: file, length: length}
+}
+
+func (r *eofInjectingReaderAt) ReadAt(p []byte, off int64) (n int, err error) {
+	if off >= r.length {
+		// If reading beyond the file length, return EOF to simulate a proper end.
+		return 0, io.EOF
+	}
+
+	// Attempt to read as usual.
+	n, err = r.file.ReadAt(p, off)
+	if err == io.ErrUnexpectedEOF || n < len(p) {
+		// If an unexpected EOF or partial read, return what we have and inject EOF.
+		return n, io.EOF
+	}
+
+	return n, err
+}
diff --git a/internal/agent/sftp/filelister.go b/internal/agent/sftp/filelister.go
index ac56bd4..0176f9e 100644
--- a/internal/agent/sftp/filelister.go
+++ b/internal/agent/sftp/filelister.go
@@ -88,8 +88,8 @@ func (h *SftpHandler) setFilePath(r *sftp.Request) {
 	r.Filepath = filepath.Join(h.Snapshot.SnapshotPath, filepath.Clean(r.Filepath))
 }
 
-func (h *SftpHandler) fetch(path string, mode int) (*os.File, error) {
-	return os.OpenFile(path, mode, 0777)
+func (h *SftpHandler) fetch(path string) (*os.File, error) {
+	return os.Open(path)
 }
 
 func wildcardToRegex(pattern string) string {
@@ -175,13 +175,5 @@ func skipFile(path string, fileInfo os.FileInfo) bool {
 		}
 	}
 
-	if !fileInfo.IsDir() {
-		f, err := os.Open(path)
-		if err != nil {
-			return true
-		}
-		f.Close()
-	}
-
 	return false
 }
diff --git a/internal/agent/sftp/handler.go b/internal/agent/sftp/handler.go
index 0ed8455..59604f9 100644
--- a/internal/agent/sftp/handler.go
+++ b/internal/agent/sftp/handler.go
@@ -40,12 +40,19 @@ func (h *SftpHandler) Fileread(r *sftp.Request) (io.ReaderAt, error) {
 	h.Snapshot.UpdateTimestamp()
 	h.setFilePath(r)
 
-	file, err := h.fetch(r.Filepath, os.O_RDONLY)
+	file, err := h.fetch(r.Filepath)
 	if err != nil {
 		log.Printf("error reading file: %v", err)
 		return nil, err
 	}
-	return file, nil
+
+	stat, err := os.Lstat(r.Filepath)
+	if err != nil {
+		log.Printf("error getting file stats: %v", err)
+		return nil, err
+	}
+
+	return NewEOFInjectingReaderAt(file, stat.Size()), nil
 }
 
 func (h *SftpHandler) Filewrite(r *sftp.Request) (io.WriterAt, error) {
diff --git a/internal/backend/mount/mount.go b/internal/backend/mount/mount.go
index 352afde..265d8cc 100644
--- a/internal/backend/mount/mount.go
+++ b/internal/backend/mount/mount.go
@@ -60,7 +60,7 @@ func Mount(target *store.Target) (*AgentMount, error) {
 		"--sftp-user", "proxmox",
 		"--sftp-host", agentHost,
 		"--allow-other",
-		"--sftp-shell-type", "unix",
+		"--sftp-shell-type", "none",
 		":sftp:/", agentMount.Path,
 	}