SCP receive file size error on windows.

[xiaoniu-578fa6bff964d005]

When I download a file of 4 bytes size, ScpFileStat.size() shows 1552549416, which is actually current time.

Some debug indicate that this issue is caused by different layout between libc::windows::stat and stat.

Here are the interpretations of same memory block for libc::windows::stat:

and for stat:

The libssh2_struct_stat have same layout with libc::windows::stat, however the input argument of libssh2_scp_recv in libssh2-sys is of type stat, ref.

Here is the memory layout of libc::windows::stat on my computer:
type: libc::windows::stat: 56 bytes, alignment: 8 bytes
field .st_dev: 4 bytes
field .st_ino: 2 bytes
field .st_mode: 2 bytes
field .st_nlink: 2 bytes
field .st_uid: 2 bytes
field .st_gid: 2 bytes
padding: 2 bytes
field .st_rdev: 4 bytes, alignment: 4 bytes
padding: 4 bytes
field .st_size: 8 bytes, alignment: 8 bytes
field .st_atime: 8 bytes
field .st_mtime: 8 bytes
field .st_ctime: 8 bytes
Size of stat: 48 bytes.

My environment:
rustc 1.32.0 (9fda7c223 2019-01-16)
stable-x86_64-pc-windows-msvc and stable-x86_64-pc-windows-gnu(with MinGW-W64)

cargo.lock:
libssh2-sys 0.2.11
libc 0.2.50

[xiaoniu-578fa6bff964d005]

It confuse me a lot why stat and libssh2_struct_stat have different size.
According to this line they should be same.

[alexcrichton]

This may be a case where stat vs stat64 or something like that is causing problems, and this is likely a bug in the libssh2-sys crate itself.

If you can checkout the repository and run cargo run in systest it should alert any differences between the two

[valerius21]

Unfortunately, it does not.

warning: cl : Command line warning D9025 : overriding '/W4' with '/W3'
warning: use of deprecated item 'std::sync::atomic::ATOMIC_BOOL_INIT': the `new` function is now preferred
 --> C:\Users\Valerius\Desktop\_ssh\ssh2-rs\target\debug\build\systest-07db2a0d3075e19a\out/all.rs:4:49
  |
4 |             use std::sync::atomic::{AtomicBool, ATOMIC_BOOL_INIT, Ordering};
  |                                                 ^^^^^^^^^^^^^^^^
  |
  = note: #[warn(deprecated)] on by default

warning: use of deprecated item 'std::sync::atomic::ATOMIC_USIZE_INIT': the `new` function is now preferred
 --> C:\Users\Valerius\Desktop\_ssh\ssh2-rs\target\debug\build\systest-07db2a0d3075e19a\out/all.rs:5:50
  |
5 |             use std::sync::atomic::{AtomicUsize, ATOMIC_USIZE_INIT};
  |                                                  ^^^^^^^^^^^^^^^^^

warning: use of deprecated item 'std::sync::atomic::ATOMIC_BOOL_INIT': the `new` function is now preferred
  --> C:\Users\Valerius\Desktop\_ssh\ssh2-rs\target\debug\build\systest-07db2a0d3075e19a\out/all.rs:41:41
   |
41 |             static FAILED: AtomicBool = ATOMIC_BOOL_INIT;
   |                                         ^^^^^^^^^^^^^^^^
help: use of deprecated item 'std::sync::atomic::ATOMIC_BOOL_INIT': the `new` function is now preferred
   |
41 |             static FAILED: AtomicBool = AtomicBool::new(false);
   |                                         ^^^^^^^^^^^^^^^^^^^^^^

warning: use of deprecated item 'std::sync::atomic::ATOMIC_USIZE_INIT': the `new` function is now preferred
  --> C:\Users\Valerius\Desktop\_ssh\ssh2-rs\target\debug\build\systest-07db2a0d3075e19a\out/all.rs:42:42
   |
42 |             static NTESTS: AtomicUsize = ATOMIC_USIZE_INIT;
   |                                          ^^^^^^^^^^^^^^^^^
help: use of deprecated item 'std::sync::atomic::ATOMIC_USIZE_INIT': the `new` function is now preferred
   |
42 |             static NTESTS: AtomicUsize = AtomicUsize::new(0);
   |                                          ^^^^^^^^^^^^^^^^^^^

    Finished dev [unoptimized + debuginfo] target(s) in 1m 04s
     Running `C:\Users\Valerius\Desktop\_ssh\ssh2-rs\target\debug\systest.exe`
RUNNING ALL TESTS
PASSED 769 tests

It does compile just fine on Windows 10, however the issue remains.

[JoyceBabu]

I am also seeing the same issue. ScpFileStat::size is returning the timestamp instead of the actual filesize.

[JoyceBabu]

On 64 bit build it is returning the timestamp. But on 32 bit build, it is returning an even bigger number.

For a file of size 40960 bytes, I am getting the following sizes depending on the target architecture.

64 Bit - 1563919174
32 Bit - 6716986311686195062

[JoyceBabu]

The issue happens when libssh2 is compiled with large file support for windows enabled. When it is enabled, libssh2_struct_stat is an alias for _stati64.

I found the following comment in libssh2/include/libssh2.h

/* libssh2_scp_recv is DEPRECATED, do not use! */
LIBSSH2_API LIBSSH2_CHANNEL *libssh2_scp_recv(LIBSSH2_SESSION *session,
                                              const char *path,
                                              struct stat *sb);
/* Use libssh2_scp_recv2 for large (> 2GB) file support on windows */
LIBSSH2_API LIBSSH2_CHANNEL *libssh2_scp_recv2(LIBSSH2_SESSION *session,
                                               const char *path,
                                               libssh2_struct_stat *sb);

So I tried updating sess.scp_recv to use libssh2_scp_recv2 instead of the deprecated libssh2_scp_recv, and now it is working correctly on both Windows and macOS.