Improve image mount failure handling

[petrutlucian94]

As shown by the following logs, ISO image mounting can fail silently. We won't get a drive letter, nor a non-zero exit code. However, attempting to subsequently dismount the image fails.

This change will raise an exception if no drive letter was received, including the original stderr as well as the image file size, which can help us determine if an invalid image was received.

2026-06-05 13:39:01.124 DEBUG coriolis.wsman [-] Executing PS command: (Mount-DiskImage 'c:\virtio-win.iso' -PassThru | Get-Volume).DriveLetter from (pid=4517) exec_ps_command /var/log/coriolis/cori
olis/coriolis/wsman.py:149
2026-06-05 13:39:08.868 DEBUG coriolis.wsman [-] Executing PS command: Test-Path -Path ":\Balloon\2k25\amd64" from (pid=4517) exec_ps_command /var/log/coriolis/coriolis/coriolis/wsman.py:149
2026-06-05 13:39:11.554 DEBUG coriolis.wsman [-] Executing PS command: Test-Path -Path ":\Balloon\2k22\amd64" from (pid=4517) exec_ps_command /var/log/coriolis/coriolis/coriolis/wsman.py:149
2026-06-05 13:39:14.094 DEBUG coriolis.wsman [-] Executing PS command: Test-Path -Path ":\Balloon\2k19\amd64" from (pid=4517) exec_ps_command /var/log/coriolis/coriolis/coriolis/wsman.py:149
2026-06-05 13:39:16.689 DEBUG coriolis.wsman [-] Executing PS command: Test-Path -Path ":\Balloon\2k16\amd64" from (pid=4517) exec_ps_command /var/log/coriolis/coriolis/coriolis/wsman.py:149
2026-06-05 13:39:19.331 DEBUG coriolis.wsman [-] Executing PS command: Test-Path -Path ":\Balloon\w10\amd64" from (pid=4517) exec_ps_command /var/log/coriolis/coriolis/coriolis/wsman.py:149
2026-06-05 13:39:21.893 DEBUG coriolis.wsman [-] Executing PS command: Test-Path -Path ":\Balloon\2k12R2\amd64" from (pid=4517) exec_ps_command /var/log/coriolis/coriolis/coriolis/wsman.py:149
2026-06-05 13:39:24.450 DEBUG coriolis.wsman [-] Executing PS command: Test-Path -Path ":\Balloon\2k12\amd64" from (pid=4517) exec_ps_command /var/log/coriolis/coriolis/coriolis/wsman.py:149
2026-06-05 13:39:27.054 DEBUG coriolis.wsman [-] Executing PS command: Test-Path -Path ":\Balloon\2k8R2\amd64" from (pid=4517) exec_ps_command /var/log/coriolis/coriolis/coriolis/wsman.py:149
2026-06-05 13:39:29.755 DEBUG coriolis.wsman [-] Executing PS command: Test-Path -Path ":\Balloon\2k8\amd64" from (pid=4517) exec_ps_command /var/log/coriolis/coriolis/coriolis/wsman.py:149
2026-06-05 13:39:32.449 DEBUG coriolis.wsman [-] Executing PS command: Test-Path -Path ":\Balloon\2k3\amd64" from (pid=4517) exec_ps_command /var/log/coriolis/coriolis/coriolis/wsman.py:149
2026-06-05 13:39:35.011 INFO coriolis.osmorphing.windows [-] Unmounting disk image: c:\virtio-win.iso
...
2026-06-05 13:40:04.250 TRACE coriolis.worker.rpc.server     self._conn.exec_ps_command("Dismount-DiskImage '%s'" % path,
2026-06-05 13:40:04.250 TRACE coriolis.worker.rpc.server   File "/var/log/coriolis/coriolis/coriolis/wsman.py", line 151, in exec_ps_command
2026-06-05 13:40:04.250 TRACE coriolis.worker.rpc.server     return self.exec_command(
2026-06-05 13:40:04.250 TRACE coriolis.worker.rpc.server   File "/var/log/coriolis/coriolis/coriolis/wsman.py", line 141, in exec_command
2026-06-05 13:40:04.250 TRACE coriolis.worker.rpc.server     raise exception.CoriolisException(
2026-06-05 13:40:04.250 TRACE coriolis.worker.rpc.server coriolis.exception.CoriolisException: Command "['powershell.exe', '-EncodedCommand', 'RABpAHMAbQBvAHUAbgB0AC0ARABpAHMAawBJAG0AYQBnAGUAIAAnAGMAOgBcAHYAaQByAHQAaQBvAC0AdwBpAG4ALgBpAHMAbwAnAA==', '-NonInteractive', '-ExecutionPolicy', 'RemoteSigned']" failed with exit code: 1
2026-06-05 13:40:04.250 TRACE coriolis.worker.rpc.server stdout:
2026-06-05 13:40:04.250 TRACE coriolis.worker.rpc.server std_err: #< CLIXML
2026-06-05 13:40:04.250 TRACE coriolis.worker.rpc.server <Objs Version="1.1.0.1" xmlns="http://schemas.microsoft.com/powershell/2004/04"><Obj S="progress" RefId="0"><TN RefId="0"><T>System.Management.Automation.PSCustomObject</T><T>System.Object</T></TN><MS><I64 N="SourceId">1</I64><PR N="Record"><AV>Preparing modules for first use.</AV><AI>0</AI><Nil /><PI>-1</PI><PC>-1</PC><T>Completed</T><SR>-1</SR><SD> </SD></PR></MS></Obj><Obj S="progress" RefId="1"><TNRef RefId="0" /><MS><I64 N="SourceId">2</I64><PR N="Record"><AV>Preparing modules for first use.</AV><AI>0</AI><Nil /><PI>-1</PI><PC>-1</PC><T>Completed</T><SR>-1</SR><SD> </SD></PR></MS></Obj><Obj S="progress" RefId="2"><TNRef RefId="0" /><MS><I64 N="SourceId">3</I64><PR N="Record"><AV>Preparing modules for first use.</AV><AI>0</AI><Nil /><PI>-1</PI><PC>-1</PC><T>Completed</T><SR>-1</SR><SD> </SD></PR></MS></Obj><S S="Error">Dismount-DiskImage : The request could not be performed because of an I/O device error. _x000D__x000A_</S><S S="Error">At line:1 char:1_x000D__x000A_</S><S S="Error">+ Dismount-DiskImage 'c:\virtio-win.iso'_x000D__x000A_</S><S S="Error">+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~_x000D__x000A_</S><S S="Error">    + CategoryInfo          : NotSpecified: (MSFT_DiskImage:ROOT/Microsoft/.../MSFT_DiskImage) [Dismount-DiskImage], C _x000D__x000A_</S><S S="Error">   imException_x000D__x000A_</S><S S="Error">    + FullyQualifiedErrorId : HRESULT 0x8007045d,Dismount-DiskImage_x000D__x000A_</S><S S="Error"> _x000D__x000A_</S><Obj S="progress" RefId="3"><TNRef RefId="0" /><MS><I64 N="SourceId">4</I64><PR N="Record"><AV>Dismount-DiskImage 'c:\virtio-win.iso'</AV><AI>1393322851</AI><Nil /><PI>-1</PI><PC>100</PC><T>Completed</T><SR>0</SR><SD>1/1 completed</SD></PR></MS></Obj></Objs

[petrutlucian94]

I've corrupted the iso intentionally but the initial mount command silently passed. With this change we'll get a proper error:

def _mount_disk_image(self, path):
         LOG.info("Mounting disk image: %s" % path)
+        self._conn.exec_ps_command(f"echo test > {path}")
         drive_letter, stderr = self._conn.exec_ps_command(
             "(Mount-Disk

Could not mount image: 'c:\virtio-win.iso', file size: 14, mount stderr: #< CLIXML
<Objs Version="1.1.0.1" xmlns="http://schemas.microsoft.com/powershell/2004/04"><Obj S="progress" RefId="0"><TN RefId="0"><T>System.Management.Automation.PSCustomObject</T><T>System.Object</T></TN><MS><I64 N="SourceId">1</I64><PR N="Record"><AV>Preparing modules for first use.</AV><AI>0</AI><Nil /><PI>-1</PI><PC>-1</PC><T>Completed</T><SR>-1</SR><SD> </SD></PR></MS></Obj><Obj S="progress" RefId="1"><TNRef RefId="0" /><MS><I64 N="SourceId">2</I64><PR N="Record"><AV>Preparing modules for first use.</AV><AI>0</AI><Nil /><PI>-1</PI><PC>-1</PC><T>Completed</T><SR>-1</SR><SD> </SD></PR></MS></Obj><Obj S="progress" RefId="2"><TNRef RefId="0" /><MS><I64 N="SourceId">3</I64><PR N="Record"><AV>Preparing modules for first use.</AV><AI>0</AI><Nil /><PI>-1</PI><PC>-1</PC><T>Completed</T><SR>-1</SR><SD> </SD></PR></MS></Obj><S S="Error">Mount-DiskImage : The file or directory is corrupted and unreadable. _x000D__x000A_</S><S S="Error">At line:1 char:2_x000D__x000A_</S><S S="Error">+ (Mount-DiskImage 'c:\virtio-win.iso' -PassThru | Get-Volume).DriveLet ..._x000D__x000A_</S><S S="Error">+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~_x000D__x000A_</S><S S="Error"> + CategoryInfo : NotSpecified: (MSFT_DiskImage:ROOT/Microsoft/.../MSFT_DiskImage) [Mount-DiskImage], CimE _x000D__x000A_</S><S S="Error"> xception_x000D__x000A_</S><S S="Error"> + FullyQualifiedErrorId : HRESULT 0x80070570,Mount-DiskImage_x000D__x000A_</S><S S="Error"> _x000D__x000A_</S><Obj S="progress" RefId="3"><TNRef RefId="0" /><MS><I64 N="SourceId">4</I64><PR N="Record"><AV>Mount-DiskImage 'c:\virtio-win.iso' -PassThru | Get-Volume).DriveLetter</AV><AI>1580446388</AI><Nil /><PI>-1</PI><PC>100</PC><T>Completed</T><SR>0</SR><SD>1/1 completed</SD></PR></MS></Obj></Objs>