[Libguestfs] Issue with downloading files whose path contains multi-byte utf-8 characters

[Yonatan Shtarkman]

The attached code snippet reproduces the issue when running:
python3 libugestfs_segfault_repro.py

With:
guestfs version: 1.48.6
guestfs-python version: 1.48.6

Stacktrace:
#0  0x00007f6dd17b4701 in _Py_INCREF (op=<optimized out>) at
/usr/include/python3.9/object.h:408
408    op->ob_refcnt++;
(gdb) bt
#0  0x00007f6dd17b4701 in _Py_INCREF (op=<optimized out>) at
/usr/include/python3.9/object.h:408
#1  guestfs_int_py_event_callback_wrapper
    (g=<optimized out>, flags=<optimized out>, array_len=0, array=0x0,
buf_len=43, buf=0xd1dc90 "commandrvf: udevadm --debug settle -E
/\347\232\204\303 available\r\ned7
#2  guestfs_int_py_event_callback_wrapper
    (g=<optimized out>, callback=0x7f6dd19ec040, event=16, event_handle=0,
flags=<optimized out>, buf=0xd1dc90 "commandrvf: udevadm --debug settle -E
/\347\232\204\303 4
#3  0x00007f6dd166f9aa in guestfs_int_call_callbacks_message
    (g=0xae06f0, event=16, buf=0xd1dc90 "commandrvf: udevadm --debug settle
-E /\347\232\204\303 available\r\ned to rvf:e run  in, ignor data av",
buf_len=43)
    at events.c:117
#4  0x00007f6dd168560e in guestfs_int_log_message_callback
    (g=g at entry=0xae06f0, buf=0xd1dc90 "commandrvf: udevadm --debug settle
-E /\347\232\204\303 available\r\ned to rvf:e run  in, ignor data av",
len=len at entry=43)
    at proto.c:145
#5  0x00007f6dd166ac29 in handle_log_message (g=g at entry=0xae06f0,
conn=conn at entry=0xd19570) at conn-socket.c:395
#6  0x00007f6dd166b233 in read_data (len=4, bufv=<optimized out>,
connv=<optimized out>, g=<optimized out>) at conn-socket.c:179
#7  read_data (g=0xae06f0, connv=0xd19570, bufv=<optimized out>, len=4) at
conn-socket.c:142
#8  0x00007f6dd1685c2a in recv_from_daemon (buf_rtn=0x7fffa95cc548,
size_rtn=0x7fffa95cc544, g=0xae06f0) at proto.c:545
#9  guestfs_int_recv_from_daemon (g=g at entry=0xae06f0,
size_rtn=size_rtn at entry=0x7fffa95cc544, buf_rtn=buf_rtn at entry=0x7fffa95cc548)
at proto.c:623
#10 0x00007f6dd168603a in guestfs_int_recv
    (g=g at entry=0xae06f0, fn=fn at entry=0x7f6dd16aa308 "download",
hdr=hdr at entry=0x7fffa95cc610, err=err at entry=0x7fffa95cc5e0,
xdrp=xdrp at entry=0x0,
ret=ret at entry=0x0)
    at proto.c:668
#11 0x00007f6dd163825e in guestfs_download (g=g at entry=0xae06f0,
remotefilename=<optimized out>, filename=0x7f6dd17edea0 "/tmp/1") at
actions-5.c:2984
#12 0x00007f6dd17ab01a in guestfs_int_py_download (self=<optimized out>,
args=<optimized out>) at actions-5.c:794



On Mon, Feb 13, 2023 at 10:16 PM Richard W.M. Jones <rjones at redhat.com>
wrote:

> On Mon, Feb 13, 2023 at 09:38:50PM +0200, Yonatan Shtarkman wrote:
> > Also, as a workaround, I avoided calling the event callback if null is
> returned
> > by Py_BuildValue (still print the error and release the thread).
> > This seems to work for our usage (we only use the event callbacks for
> logging),
> > any potential issues I'm missing?
>
> Oh I see so the issue is actually when logging and not in the download
> call?  That's strange that it should be happening intermittently.  I'd
> expect a UTF-8 encoding error would happen every time not sometimes.
>
> Rich.
>
> --
> Richard Jones, Virtualization Group, Red Hat
> http://people.redhat.com/~rjones
> Read my programming and virtualization blog: http://rwmj.wordpress.com
> virt-top is 'top' for virtual machines.  Tiny program with many
> powerful monitoring features, net stats, disk stats, logging, etc.
> http://people.redhat.com/~rjones/virt-top
>
>
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