From 2c44f913e8a4ecea5e80eb784bb32b52785d0a12 Mon Sep 17 00:00:00 2001
From: Cyp <cyp@wz2100.net>
Date: Sat, 28 Oct 2023 11:28:59 +0200
Subject: [PATCH] On partial read/write, keep reading.

This avoids rsync errors and avoids data loss with cp, due to
failing to copy the last byte of 0.1953125% of files.

Unless direct_io is set, fuse expects a full read/write.

As a workaround for a device hanging bug, if the length of a file
on a Samsung device is 500 bytes modulo 512 bytes, libmtp returns a
partial read omitting the last byte which must be requested
separately.

Fixes #85.
---
 src/simple-mtpfs-fuse.cpp       | 32 ++++++++++++++++++++++++++++++--
 src/simple-mtpfs-mtp-device.cpp |  1 +
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/src/simple-mtpfs-fuse.cpp b/src/simple-mtpfs-fuse.cpp
index f842b06..e01a398 100644
--- a/src/simple-mtpfs-fuse.cpp
+++ b/src/simple-mtpfs-fuse.cpp
@@ -85,13 +85,41 @@ int wrap_open(const char *path, struct fuse_file_info *file_info)
 int wrap_read(const char *path, char *buf, size_t size, off_t offset,
     struct fuse_file_info *file_info)
 {
-    return SMTPFileSystem::instance()->read(path, buf, size, offset, file_info);
+    if (file_info->direct_io) {
+        return SMTPFileSystem::instance()->read(path, buf, size, offset, file_info);
+    } else {
+        int bytes_read = 0;
+        while (bytes_read < size) {
+            int rval = SMTPFileSystem::instance()->read(path, buf + bytes_read, size - bytes_read, offset + bytes_read, file_info);
+            if (rval < 0) {
+                return rval;
+            } else if (rval == 0) {
+                break;
+            }
+            bytes_read += rval;
+        }
+        return bytes_read;
+    }
 }
 
 int wrap_write(const char *path, const char *buf, size_t size, off_t offset,
     struct fuse_file_info *file_info)
 {
-    return SMTPFileSystem::instance()->write(path, buf, size, offset, file_info);
+    if (file_info->direct_io) {
+        return SMTPFileSystem::instance()->write(path, buf, size, offset, file_info);
+    } else {
+        int bytes_written = 0;
+        while (bytes_written < size) {
+            int rval = SMTPFileSystem::instance()->write(path, buf + bytes_written, size - bytes_written, offset + bytes_written, file_info);
+            if (rval < 0) {
+                return rval;
+            } else if (rval == 0) {
+                break;
+            }
+            bytes_written += rval;
+        }
+        return bytes_written;
+    }
 }
 
 int wrap_statfs(const char *path, struct statvfs *stat_info)
diff --git a/src/simple-mtpfs-mtp-device.cpp b/src/simple-mtpfs-mtp-device.cpp
index 3b80c7a..50cac02 100644
--- a/src/simple-mtpfs-mtp-device.cpp
+++ b/src/simple-mtpfs-mtp-device.cpp
@@ -720,6 +720,7 @@ bool MTPDevice::listDevices(bool verbose, const std::string &dev_file)
             continue;
         std::cout << i + 1 << ": "
             << (raw_devices[i].device_entry.vendor ? raw_devices[i].device_entry.vendor : "Unknown vendor ")
+            << ", "
             << (raw_devices[i].device_entry.product ? raw_devices[i].device_entry.product : "Unknown product")
             << std::endl;
 #ifdef HAVE_LIBMTP_CHECK_CAPABILITY