[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]

Re: [libvirt] [PATCH 1/4] qemu: Add checking in helpers for sgio setting



On 2013年02月11日 19:14, Daniel P. Berrange wrote:
On Mon, Feb 11, 2013 at 07:09:29PM +0800, Osier Yang wrote:
On 2013年02月11日 18:48, Daniel P. Berrange wrote:
On Mon, Feb 11, 2013 at 06:35:42PM +0800, Osier Yang wrote:
On 2013年02月09日 04:21, John Ferlan wrote:
On 02/08/2013 08:07 AM, Osier Yang wrote:
This moves the checking into the helpers, to avoid the
callers missing the checking.
---
  src/qemu/qemu_conf.c    |   20 ++++++++++++++++----
  src/qemu/qemu_conf.h    |    4 ++--
  src/qemu/qemu_driver.c  |   18 +++++++-----------
  src/qemu/qemu_process.c |   21 ++++++++++++---------
  4 files changed, 37 insertions(+), 26 deletions(-)

diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c
index 17f7d45..69ba710 100644
--- a/src/qemu/qemu_conf.c
+++ b/src/qemu/qemu_conf.c
@@ -726,12 +726,20 @@ qemuGetSharedDiskKey(const char *disk_path)
   */
  int
  qemuAddSharedDisk(virHashTablePtr sharedDisks,
-                  const char *disk_path)
+                  virDomainDiskDefPtr disk)
  {
      size_t *ref = NULL;
      char *key = NULL;

-    if (!(key = qemuGetSharedDiskKey(disk_path)))
+    /* Currently the only conflicts we have to care about
+     * for the shared disk is "sgio" setting, which is only
+     * valid for block disk.
+     */
+    if (disk->type != VIR_DOMAIN_DISK_TYPE_BLOCK ||
+        !disk->shared || !disk->src)
+        return 0;
+
+    if (!(key = qemuGetSharedDiskKey(disk->src)))
          return -1;

      if ((ref = virHashLookup(sharedDisks, key))) {
@@ -755,12 +763,16 @@ qemuAddSharedDisk(virHashTablePtr sharedDisks,
   */
  int
  qemuRemoveSharedDisk(virHashTablePtr sharedDisks,
-                     const char *disk_path)
+                     virDomainDiskDefPtr disk)
  {
      size_t *ref = NULL;
      char *key = NULL;

-    if (!(key = qemuGetSharedDiskKey(disk_path)))
+    if (disk->type != VIR_DOMAIN_DISK_TYPE_BLOCK ||
+        !disk->shared || !disk->src)
+        return 0;

[2]

+
+    if (!(key = qemuGetSharedDiskKey(disk->src)))
          return -1;

      if (!(ref = virHashLookup(sharedDisks, key))) {
diff --git a/src/qemu/qemu_conf.h b/src/qemu/qemu_conf.h
index 60c4109..8e84bcf 100644
--- a/src/qemu/qemu_conf.h
+++ b/src/qemu/qemu_conf.h
@@ -270,11 +270,11 @@ void qemuDriverCloseCallbackRunAll(virQEMUDriverPtr driver,
                                     virConnectPtr conn);

  int qemuAddSharedDisk(virHashTablePtr sharedDisks,
-                      const char *disk_path)
+                      virDomainDiskDefPtr disk)
      ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2);

  int qemuRemoveSharedDisk(virHashTablePtr sharedDisks,
-                         const char *disk_path)
+                         virDomainDiskDefPtr disk)
      ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2);
  char * qemuGetSharedDiskKey(const char *disk_path)
      ATTRIBUTE_NONNULL(1);
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 979a027..043efd3 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -5855,11 +5855,9 @@ qemuDomainAttachDeviceDiskLive(virConnectPtr conn,
      }

      if (ret == 0) {
-        if (disk->type == VIR_DOMAIN_DISK_TYPE_BLOCK&&    disk->shared) {
-            if (qemuAddSharedDisk(driver->sharedDisks, disk->src)<    0)
-                VIR_WARN("Failed to add disk '%s' to shared disk table",
-                         disk->src);
-        }
+        if (qemuAddSharedDisk(driver->sharedDisks, disk)<    0)
+            VIR_WARN("Failed to add disk '%s' to shared disk table",
+                     disk->src);

          if (qemuSetUnprivSGIO(disk)<    0)
              VIR_WARN("Failed to set unpriv_sgio of disk '%s'", disk->src);

Does there need to be a NULLSTR(disk->src)?  Doesn't seem so, but just
checking.  I only note this because the qemuAddSharedDisk() has a
!disk->src check prior to returning zero.

qemuSetUnprivSGIO returns 0 as long as disk->src is NULL too. See [1].

If disk->type == NETWORK, then de-referencing disk->src has potential to
SEGV the entire process, since that field is not valid.

There is checking in this version:

     /* "sgio" is only valid for block disk; cdrom
      * and floopy disk can have empty source.
      */
     if (disk->type != VIR_DOMAIN_DISK_TYPE_BLOCK ||
         !disk->src)
         return 0;

So for a network disk, it has no chance to de-reference disk->src
if the return value<  0.

Hmm, that is rather unclear, and looking at the code is also just
something we don't need. These methods are doing virRaiseError,
so we shouldn't also be doing VIR_WARN - just remove these VIR_WARN
lines from all this code.


They are removed in 4/4. :)

Osier


[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]