[libvirt] [PATCH] don't leak a file descriptor on failed pciGetDevice call
Jim Meyering
jim at meyering.net
Tue Mar 3 10:35:40 UTC 2009
Daniel P. Berrange wrote:
> On Tue, Mar 03, 2009 at 11:21:16AM +0100, Jim Meyering wrote:
>> Daniel P. Berrange wrote:
>> > On Tue, Mar 03, 2009 at 11:13:40AM +0100, Jim Meyering wrote:
>> >> This loop would mistakenly return early (skipping the closedir)
>> >> upon pciGetDevice failure.
>> >>
>> >> >From 2d4d1d25edf8f1c3f4770707215bba67d73fd59f Mon Sep 17 00:00:00 2001
>> >> From: Jim Meyering <meyering at redhat.com>
>> >> Date: Tue, 3 Mar 2009 11:11:07 +0100
>> >> Subject: [PATCH] don't leak a file descriptor on failed pciGetDevice call
>> >
>> > ACK, but...
>> >
>> >> @@ -823,7 +827,7 @@ void
>> >> pciFreeDevice(virConnectPtr conn ATTRIBUTE_UNUSED, pciDevice *dev)
>> >> {
>> >> VIR_DEBUG("%s %s: freeing", dev->id, dev->name);
>> >> - if (dev->fd)
>> >> + if (dev->fd >= 0)
>> >> close(dev->fd);
>> >> VIR_FREE(dev);
>> >> }
>> >
>> > With this change you also need to fix the bug in pciGetDevice() which
>> > leaves 'fd' initialized to 0 rather than setting it to -1
>>
>> Ha. Good catch.
>> That change did not belong in this patch (note lack of mention in log message).
>> It belongs in a separate patch.
>
> Yes it does because, previously it would be harmless due to
>
> if (dev->fd)
>
> only check for fd > 0, but with this new patch applied it turns into a
> real bug, since the check is now fd >= 0.
There are two potential leaks. Their patches should be separate.
This change
>> >> - if (dev->fd)
>> >> + if (dev->fd >= 0)
does not belong in the patch fixing the dir-handle leak.
I'll commit these in an hour or so.
Here's the separate patch:
>From 842ac8e23b365cc460d3e03733021bed406d8e67 Mon Sep 17 00:00:00 2001
From: Jim Meyering <meyering at redhat.com>
Date: Tue, 3 Mar 2009 11:26:02 +0100
Subject: [PATCH] avoid file descriptor leak when fd == 0
* src/pci.c (pciGetDevice): Initialize dev->fd to -1, not 0.
(pciFreeDevice): Close fd also when it is 0.
---
src/pci.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/src/pci.c b/src/pci.c
index 29a6dcc..b9c781b 100644
--- a/src/pci.c
+++ b/src/pci.c
@@ -789,6 +789,7 @@ pciGetDevice(virConnectPtr conn,
return NULL;
}
+ dev->fd = -1;
dev->domain = domain;
dev->bus = bus;
dev->slot = slot;
@@ -827,7 +828,7 @@ void
pciFreeDevice(virConnectPtr conn ATTRIBUTE_UNUSED, pciDevice *dev)
{
VIR_DEBUG("%s %s: freeing", dev->id, dev->name);
- if (dev->fd)
+ if (dev->fd >= 0)
close(dev->fd);
VIR_FREE(dev);
}
--
1.6.2.rc1.285.gc5f54
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