From 8518fbb314727cbb3f747c20ef194df7cd1bdac3 Mon Sep 17 00:00:00 2001
Message-Id: <8518fbb314727cbb3f747c20ef194df7cd1bdac3@dist-git>
From: =?UTF-8?q?J=C3=A1n=20Tomko?= <jtomko@redhat.com>
Date: Wed, 28 Jan 2015 12:25:11 +0100
Subject: [PATCH] Split qemuDomainChrInsert into two parts
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https://bugzilla.redhat.com/show_bug.cgi?id=1195155

Do the allocation first, then add the actual device.
The second part should never fail. This is good
for live hotplug where we don't want to remove the device
on OOM after the monitor command succeeded.

The only change in behavior is that on failure, the
vmdef->consoles array is freed, not just the first console.

(cherry picked from commit daf51be5f1b0f7b41c0813d43d6b66edfbe4f6d9)
Signed-off-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
---
 src/conf/domain_conf.c   | 18 +++++++++++++---
 src/conf/domain_conf.h   |  7 +++++--
 src/libvirt_private.syms |  3 ++-
 src/qemu/qemu_hotplug.c  | 54 +++++++++++++++++++++++++++++++++++++++++-------
 4 files changed, 68 insertions(+), 14 deletions(-)

diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index fed87f0..9bfffd0 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -11529,15 +11529,27 @@ virDomainChrGetDomainPtrs(const virDomainDef *vmdef,
 
 
 int
-virDomainChrInsert(virDomainDefPtr vmdef,
-                   virDomainChrDefPtr chr)
+virDomainChrPreAlloc(virDomainDefPtr vmdef,
+                     virDomainChrDefPtr chr)
 {
     virDomainChrDefPtr **arrPtr = NULL;
     size_t *cntPtr = NULL;
 
     virDomainChrGetDomainPtrsInternal(vmdef, chr->deviceType, &arrPtr, &cntPtr);
 
-    return VIR_APPEND_ELEMENT(*arrPtr, *cntPtr, chr);
+    return VIR_REALLOC_N(*arrPtr, *cntPtr + 1);
+}
+
+void
+virDomainChrInsertPreAlloced(virDomainDefPtr vmdef,
+                             virDomainChrDefPtr chr)
+{
+    virDomainChrDefPtr **arrPtr = NULL;
+    size_t *cntPtr = NULL;
+
+    virDomainChrGetDomainPtrsInternal(vmdef, chr->deviceType, &arrPtr, &cntPtr);
+
+    ignore_value(VIR_APPEND_ELEMENT_INPLACE(*arrPtr, *cntPtr, chr));
 }
 
 virDomainChrDefPtr
diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index b912845..1436eb8 100644
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -2543,8 +2543,11 @@ bool
 virDomainChrEquals(virDomainChrDefPtr src,
                    virDomainChrDefPtr tgt);
 int
-virDomainChrInsert(virDomainDefPtr vmdef,
-                   virDomainChrDefPtr chr);
+virDomainChrPreAlloc(virDomainDefPtr vmdef,
+                     virDomainChrDefPtr chr);
+void
+virDomainChrInsertPreAlloced(virDomainDefPtr vmdef,
+                             virDomainChrDefPtr chr);
 virDomainChrDefPtr
 virDomainChrRemove(virDomainDefPtr vmdef,
                    virDomainChrDefPtr chr);
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 325a912..18c715a 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -153,7 +153,8 @@ virDomainChrDefNew;
 virDomainChrEquals;
 virDomainChrFind;
 virDomainChrGetDomainPtrs;
-virDomainChrInsert;
+virDomainChrInsertPreAlloced;
+virDomainChrPreAlloc;
 virDomainChrRemove;
 virDomainChrSerialTargetTypeFromString;
 virDomainChrSerialTargetTypeToString;
diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
index 8a3eb27..00ce77f 100644
--- a/src/qemu/qemu_hotplug.c
+++ b/src/qemu/qemu_hotplug.c
@@ -1390,9 +1390,9 @@ int qemuDomainAttachRedirdevDevice(virQEMUDriverPtr driver,
 
 }
 
-int
-qemuDomainChrInsert(virDomainDefPtr vmdef,
-                    virDomainChrDefPtr chr)
+static int
+qemuDomainChrPreInsert(virDomainDefPtr vmdef,
+                       virDomainChrDefPtr chr)
 {
     if (chr->deviceType == VIR_DOMAIN_CHR_DEVICE_TYPE_CONSOLE &&
         chr->targetType == VIR_DOMAIN_CHR_CONSOLE_TARGET_TYPE_SERIAL) {
@@ -1407,25 +1407,63 @@ qemuDomainChrInsert(virDomainDefPtr vmdef,
         return -1;
     }
 
-    if (virDomainChrInsert(vmdef, chr) < 0)
+    if (virDomainChrPreAlloc(vmdef, chr) < 0)
         return -1;
 
     /* Due to some crazy backcompat stuff, the first serial device is an alias
      * to the first console too. If this is the case, the definition must be
      * duplicated as first console device. */
-    if (vmdef->nserials == 1 && vmdef->nconsoles == 0) {
-        if ((!vmdef->consoles && VIR_ALLOC(vmdef->consoles) < 0) ||
-            VIR_ALLOC(vmdef->consoles[0]) < 0) {
-            virDomainChrRemove(vmdef, chr);
+    if (vmdef->nserials == 0 && vmdef->nconsoles == 0 &&
+        chr->deviceType == VIR_DOMAIN_CHR_DEVICE_TYPE_SERIAL) {
+        if (!vmdef->consoles && VIR_ALLOC(vmdef->consoles) < 0)
+            return -1;
+
+        if (VIR_ALLOC(vmdef->consoles[0]) < 0) {
+            VIR_FREE(vmdef->consoles);
             return -1;
         }
+        vmdef->nconsoles++;
+    }
+    return 0;
+}
+
+static void
+qemuDomainChrInsertPreAlloced(virDomainDefPtr vmdef,
+                              virDomainChrDefPtr chr)
+{
+    virDomainChrInsertPreAlloced(vmdef, chr);
+    if (vmdef->nserials == 1 && vmdef->nconsoles == 0 &&
+        chr->deviceType == VIR_DOMAIN_CHR_DEVICE_TYPE_SERIAL) {
         vmdef->nconsoles = 1;
 
         /* Create an console alias for the serial port */
         vmdef->consoles[0]->deviceType = VIR_DOMAIN_CHR_DEVICE_TYPE_CONSOLE;
         vmdef->consoles[0]->targetType = VIR_DOMAIN_CHR_CONSOLE_TARGET_TYPE_SERIAL;
     }
+}
 
+static void
+qemuDomainChrInsertPreAllocCleanup(virDomainDefPtr vmdef,
+                                   virDomainChrDefPtr chr)
+{
+    /* Remove the stub console added by qemuDomainChrPreInsert */
+    if (vmdef->nserials == 0 && vmdef->nconsoles == 1 &&
+        chr->deviceType == VIR_DOMAIN_CHR_DEVICE_TYPE_SERIAL) {
+        VIR_FREE(vmdef->consoles[0]);
+        VIR_FREE(vmdef->consoles);
+        vmdef->nconsoles = 0;
+    }
+}
+
+int
+qemuDomainChrInsert(virDomainDefPtr vmdef,
+                    virDomainChrDefPtr chr)
+{
+    if (qemuDomainChrPreInsert(vmdef, chr) < 0) {
+        qemuDomainChrInsertPreAllocCleanup(vmdef, chr);
+        return -1;
+    }
+    qemuDomainChrInsertPreAlloced(vmdef, chr);
     return 0;
 }
 
-- 
2.3.0