From ed996604464ab1652ad8d2de3ac446f460dd2ab1 Mon Sep 17 00:00:00 2001
From: Pavel Hrdina <phrdina@redhat.com>
Date: Thu, 11 May 2017 14:09:35 +0200
Subject: [PATCH] qemu: improve detection of UNIX path generated by libvirt

Currently we consider all UNIX paths with specific prefix as generated
by libvirt, but that's a wrong assumption.  Let's make the detection
better by actually checking whether the whole path matches one of the
paths that we generate or generated in the past.

The UNIX path isn't stored in config XML since libvirt-1.3.1.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1446980

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
---
 src/qemu/qemu_domain.c                        | 66 +++++++++++++++----
 .../qemuxml2argv-channel-unix-source-path.xml | 29 ++++++++
 ...emuxml2xmlout-channel-unix-source-path.xml | 45 +++++++++++++
 tests/qemuxml2xmltest.c                       |  2 +
 4 files changed, 128 insertions(+), 14 deletions(-)
 create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-channel-unix-source-path.xml
 create mode 100644 tests/qemuxml2xmloutdata/qemuxml2xmlout-channel-unix-source-path.xml

diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 7805b76808..2264ccb56f 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -3173,24 +3173,58 @@ qemuDomainDefaultNetModel(const virDomainDef *def,
 
 
 /*
- * Clear auto generated unix socket path, i.e., the one which starts with our
- * channel directory.
+ * Clear auto generated unix socket paths:
+ *
+ * libvirt 1.2.18 and older:
+ *     {cfg->channelTargetDir}/{dom-name}.{target-name}
+ *
+ * libvirt 1.2.19 - 1.3.2:
+ *     {cfg->channelTargetDir}/domain-{dom-name}/{target-name}
+ *
+ * libvirt 1.3.3 and newer:
+ *     {cfg->channelTargetDir}/domain-{dom-id}-{short-dom-name}/{target-name}
+ *
+ * The unix socket path was stored in config XML until libvirt 1.3.0.
+ * If someone specifies the same path as we generate, they shouldn't do it.
+ *
+ * This function clears the path for migration as well, so we need to clear
+ * the path even if we are not storing it in the XML.
  */
-static void
+static int
 qemuDomainChrDefDropDefaultPath(virDomainChrDefPtr chr,
                                 virQEMUDriverPtr driver)
 {
-    virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
+    virQEMUDriverConfigPtr cfg;
+    virBuffer buf = VIR_BUFFER_INITIALIZER;
+    char *regexp = NULL;
+    int ret = -1;
 
-    if (chr->deviceType == VIR_DOMAIN_CHR_DEVICE_TYPE_CHANNEL &&
-        chr->targetType == VIR_DOMAIN_CHR_CHANNEL_TARGET_TYPE_VIRTIO &&
-        chr->source->type == VIR_DOMAIN_CHR_TYPE_UNIX &&
-        chr->source->data.nix.path &&
-        STRPREFIX(chr->source->data.nix.path, cfg->channelTargetDir)) {
-        VIR_FREE(chr->source->data.nix.path);
+    if (chr->deviceType != VIR_DOMAIN_CHR_DEVICE_TYPE_CHANNEL ||
+        chr->targetType != VIR_DOMAIN_CHR_CHANNEL_TARGET_TYPE_VIRTIO ||
+        chr->source->type != VIR_DOMAIN_CHR_TYPE_UNIX ||
+        !chr->source->data.nix.path) {
+        return 0;
     }
 
+    cfg = virQEMUDriverGetConfig(driver);
+
+    virBufferEscapeRegex(&buf, "^%s", cfg->channelTargetDir);
+    virBufferAddLit(&buf, "/([^/]+\\.)|(domain-[^/]+/)");
+    virBufferEscapeRegex(&buf, "%s$", chr->target.name);
+
+    if (virBufferCheckError(&buf) < 0)
+        goto cleanup;
+
+    regexp = virBufferContentAndReset(&buf);
+
+    if (virStringMatch(chr->source->data.nix.path, regexp))
+        VIR_FREE(chr->source->data.nix.path);
+
+    ret = 0;
+ cleanup:
+    VIR_FREE(regexp);
     virObjectUnref(cfg);
+    return ret;
 }
 
 
@@ -3458,8 +3492,10 @@ qemuDomainDeviceDefPostParse(virDomainDeviceDefPtr dev,
 
     /* clear auto generated unix socket path for inactive definitions */
     if ((parseFlags & VIR_DOMAIN_DEF_PARSE_INACTIVE) &&
-        dev->type == VIR_DOMAIN_DEVICE_CHR)
-        qemuDomainChrDefDropDefaultPath(dev->data.chr, driver);
+        dev->type == VIR_DOMAIN_DEVICE_CHR) {
+        if (qemuDomainChrDefDropDefaultPath(dev->data.chr, driver) < 0)
+            goto cleanup;
+    }
 
     /* forbid capabilities mode hostdev in this kind of hypervisor */
     if (dev->type == VIR_DOMAIN_DEVICE_HOSTDEV &&
@@ -4245,8 +4281,10 @@ qemuDomainDefFormatBuf(virQEMUDriverPtr driver,
             }
         }
 
-        for (i = 0; i < def->nchannels; i++)
-            qemuDomainChrDefDropDefaultPath(def->channels[i], driver);
+        for (i = 0; i < def->nchannels; i++) {
+            if (qemuDomainChrDefDropDefaultPath(def->channels[i], driver) < 0)
+                goto cleanup;
+        }
     }
 
  format:
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-channel-unix-source-path.xml b/tests/qemuxml2argvdata/qemuxml2argv-channel-unix-source-path.xml
new file mode 100644
index 0000000000..42cb3c387c
--- /dev/null
+++ b/tests/qemuxml2argvdata/qemuxml2argv-channel-unix-source-path.xml
@@ -0,0 +1,29 @@
+<domain type='qemu'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory unit='KiB'>219100</memory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='x86_64' machine='pc'>hvm</type>
+  </os>
+  <devices>
+    <emulator>/usr/bin/qemu-system-x86_64</emulator>
+    <channel type='unix'>
+      <source mode='bind' path='/tmp/channel/QEMUGuest1.org.qemu.guest_agent.0'/>
+      <target type='virtio' name='org.qemu.guest_agent.0'/>
+    </channel>
+    <channel type='unix'>
+      <source mode='bind' path='/tmp/channel/domain-QEMUGuest1/org.qemu.guest_agent.1'/>
+      <target type='virtio' name='org.qemu.guest_agent.1'/>
+    </channel>
+    <channel type='unix'>
+      <source mode='bind' path='/tmp/channel/domain-1-QEMUGuest1/org.qemu.guest_agent.2'/>
+      <target type='virtio' name='org.qemu.guest_agent.2'/>
+    </channel>
+    <channel type='unix'>
+      <source mode='bind' path='/tmp/channel/QEMUGuest1/org.qemu.guest_agent.3'/>
+      <target type='virtio' name='org.qemu.guest_agent.3'/>
+    </channel>
+    <memballoon model='none'/>
+  </devices>
+</domain>
diff --git a/tests/qemuxml2xmloutdata/qemuxml2xmlout-channel-unix-source-path.xml b/tests/qemuxml2xmloutdata/qemuxml2xmlout-channel-unix-source-path.xml
new file mode 100644
index 0000000000..2d8fa1e3ac
--- /dev/null
+++ b/tests/qemuxml2xmloutdata/qemuxml2xmlout-channel-unix-source-path.xml
@@ -0,0 +1,45 @@
+<domain type='qemu'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory unit='KiB'>219100</memory>
+  <currentMemory unit='KiB'>219100</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='x86_64' machine='pc'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu-system-x86_64</emulator>
+    <controller type='usb' index='0'>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/>
+    </controller>
+    <controller type='pci' index='0' model='pci-root'/>
+    <controller type='virtio-serial' index='0'>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
+    </controller>
+    <channel type='unix'>
+      <target type='virtio' name='org.qemu.guest_agent.0'/>
+      <address type='virtio-serial' controller='0' bus='0' port='1'/>
+    </channel>
+    <channel type='unix'>
+      <target type='virtio' name='org.qemu.guest_agent.1'/>
+      <address type='virtio-serial' controller='0' bus='0' port='2'/>
+    </channel>
+    <channel type='unix'>
+      <target type='virtio' name='org.qemu.guest_agent.2'/>
+      <address type='virtio-serial' controller='0' bus='0' port='3'/>
+    </channel>
+    <channel type='unix'>
+      <source mode='bind' path='/tmp/channel/QEMUGuest1/org.qemu.guest_agent.3'/>
+      <target type='virtio' name='org.qemu.guest_agent.3'/>
+      <address type='virtio-serial' controller='0' bus='0' port='4'/>
+    </channel>
+    <input type='mouse' bus='ps2'/>
+    <input type='keyboard' bus='ps2'/>
+    <memballoon model='none'/>
+  </devices>
+</domain>
diff --git a/tests/qemuxml2xmltest.c b/tests/qemuxml2xmltest.c
index 81d810537b..f8a607ffc4 100644
--- a/tests/qemuxml2xmltest.c
+++ b/tests/qemuxml2xmltest.c
@@ -551,6 +551,8 @@ mymain(void)
     DO_TEST("channel-virtio", NONE);
     DO_TEST("channel-virtio-state", NONE);
 
+    DO_TEST_FULL("channel-unix-source-path", WHEN_INACTIVE, GIC_NONE, NONE);
+
     DO_TEST("hostdev-usb-address", NONE);
     DO_TEST("hostdev-pci-address", NONE);
     DO_TEST("hostdev-vfio", NONE);
-- 
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