What were you trying to do that didn't work?

I set a customized source path for guest agent, and found it get ignored by libvirt.

Please provide the package NVR for which bug is seen:

libvirt-9.10.0-1.el9.x86_64

How reproducible:

100%

Steps to reproduce

1. Define a vm with customized source path for guest agent

   <channel type="unix">
     <source mode="bind" path="/40-a/org.qemu.guest_agent.0"/>
     <target type="virtio" name="org.qemu.guest_agent.0"/>
   </channel>
   

1. Check vm dumpxml

   # virsh dumpxml vm2 --xpath //channel
   <channel type="unix">
     <target type="virtio" name="org.qemu.guest_agent.0"/>
     <address type="virtio-serial" controller="0" bus="0" port="1"/>
   </channel>
   

1. Try other paths:
   1) /tmp/40-aa/org.qemu.guest_agent.0 ==> ignored by libvirt
   2) /tmp/libvirt/qemu/channel/40-aa/org.qemu.guest_agent.0 ==> ignored by libvirt
   3) /tmp/org.qemu.guest_agent.0 ==> not ignored by libvirt
   4) /run/libvirt/qemu/channel/2-vm2/org.qemu.guest_agent.0 ==> ignored by libvirt, expected

Expected results

The following path won't be ignored by libvirt:
/40-a/org.qemu.guest_agent.0
/tmp/40-aa/org.qemu.guest_agent.0
/tmp/libvirt/qemu/channel/40-aa/org.qemu.guest_agent.0
/tmp/org.qemu.guest_agent.0 (this one has got expected result)

Actual results

As above.

Additional info

I had a try on https://regex101.com/, I think this can be fixed by adding a "(" and ")" in the pattern.

 5438 static bool
 5439 qemuDomainChrMatchDefaultPath(const char *prefix,
 5440                               const char *infix,
 5441                               const char *target,
 5442                               const char *path)
 5443 {
 5444     g_auto(virBuffer) buf = VIR_BUFFER_INITIALIZER;
 5445     g_autofree char *regexp = NULL;
 5446  
 5447     virBufferEscapeRegex(&buf, "^%s", prefix);
 5448     if (infix)                                                                                                                              
 5449         virBufferEscapeRegex(&buf, "%s", infix);
-  5450   virBufferAddLit(&buf, "/(target/)?([^/]+\\.)|(domain-[^/]+/)|([0-9]+-[^/]+/)"); 
+  5450   virBufferAddLit(&buf, "/(target/)?(([^/]+\\.)|(domain-[^/]+/)|([0-9]+-[^/]+/))");
 5451     virBufferEscapeRegex(&buf, "%s$", target);
 5452  
 5453     regexp = virBufferContentAndReset(&buf);
 5454  
 5455     return virStringMatch(path, regexp);
 5456 }