4:17 p.m.
From: "Jesse J. Cook" <jcook(a)camber.com>
The example program makes a call to virEventRegisterDefaultImpl before calling
virConnectOpen without a call to virInitialize. Interestingly enough, the
example code works. However, once you introduce a call to g_string_new it
breaks. This can result in unintentional misuse of the API.
Relates to: Red Hat Bugzilla – Bug 961155
Jesse J. Cook (2):
dom event example: init before register event impl
dom event example: Add error check to impl call
examples/domain-events/events-c/event-test.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
--
1.7.10.4
4:17 p.m.
New subject: [libvirt] [PATCH 1/2] dom event example: init before register event impl
From: "Jesse J. Cook" <jesse.j.cook(a)member.fsf.org>
In the domain-events example C code virEventRegisterDefaultImpl was being
called before virConnectOpen without first calling virInitialize. While this
code worked, it is incorrect. Adding a call to g_string_new prior to the call
to virEventRegisterDefaultImpl would cause the code to break. This fix will
help avoid unintentional misue of the API.
Relates to: Ret Hat Bugzilla - Bug 961155
---
examples/domain-events/events-c/event-test.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/examples/domain-events/events-c/event-test.c
b/examples/domain-events/events-c/event-test.c
index ede9796..09ec6aa 100644
--- a/examples/domain-events/events-c/event-test.c
+++ b/examples/domain-events/events-c/event-test.c
@@ -468,6 +468,12 @@ int main(int argc, char **argv)
return -1;
}
+ if(0 != virInitialize()) {
+ virErrorPtr err = virGetLastError();
+ fprintf(stderr, "Failed to initialize: %s\n",
+ err && err->message ? err->message: "Unknown
error");
+ }
+
virEventRegisterDefaultImpl();
virConnectPtr dconn = NULL;
--
1.7.10.4
4:21 a.m.
New subject: [libvirt] [PATCH 1/2] dom event example: init before register event impl
On 09.05.2013 23:17, Jesse J. Cook wrote:
From: "Jesse J. Cook" <jesse.j.cook(a)member.fsf.org>
In the domain-events example C code virEventRegisterDefaultImpl was being
called before virConnectOpen without first calling virInitialize. While this
code worked, it is incorrect. Adding a call to g_string_new prior to the call
to virEventRegisterDefaultImpl would cause the code to break. This fix will
help avoid unintentional misue of the API.
Not even g_string_new but even our doc require virInitialize to be called prior any
libvirt API other than virConnectOpen*(). This rule includes
VirEventRegisterDefaultImpl().
Relates to: Ret Hat Bugzilla - Bug 961155
---
examples/domain-events/events-c/event-test.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/examples/domain-events/events-c/event-test.c
b/examples/domain-events/events-c/event-test.c
index ede9796..09ec6aa 100644
--- a/examples/domain-events/events-c/event-test.c
+++ b/examples/domain-events/events-c/event-test.c
@@ -468,6 +468,12 @@ int main(int argc, char **argv)
return -1;
}
+ if(0 != virInitialize()) {
Actually, we prefer the other way:
if (virInitialize() < 0) {
+ virErrorPtr err = virGetLastError();
+ fprintf(stderr, "Failed to initialize: %s\n",
+ err && err->message ? err->message: "Unknown
error");
s/:/ :/
Moreover, we should return here, shouldn't we?
And are we save to call virGetLastError()? I don't think so. I mean, the first thing
that virInitialize() does, is thread library initialize (on linux it's nada function,
but not on windows), then it initialize thread local variable - the virError object.
And what if this fails for some reason - then virgetLastError may access invalid memory.
So I thing we should just fprintf(stderr, "Failed to initialize libvirt");
+ }
+
virEventRegisterDefaultImpl();
virConnectPtr dconn = NULL;
However, this is a nasty violation of our own rules, so ACK with this squashed in:
diff --git a/examples/domain-events/events-c/event-test.c
b/examples/domain-events/events-c/event-test.c
index 09ec6aa..0f7be55 100644
--- a/examples/domain-events/events-c/event-test.c
+++ b/examples/domain-events/events-c/event-test.c
@@ -468,10 +468,9 @@ int main(int argc, char **argv)
return -1;
}
- if(0 != virInitialize()) {
- virErrorPtr err = virGetLastError();
- fprintf(stderr, "Failed to initialize: %s\n",
- err && err->message ? err->message: "Unknown
error");
+ if (virInitialize() < 0) {
+ fprintf(stderr, "Failed to initialize libvirt");
+ return -1;
}
virEventRegisterDefaultImpl();
Michal
4:17 p.m.
New subject: [libvirt] [PATCH 2/2] dom event example: Add error check to impl call
From: "Jesse J. Cook" <jesse.j.cook(a)member.fsf.org>
Added error checking to virEventRegisterDefaultImpl call for consistency.
---
examples/domain-events/events-c/event-test.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/examples/domain-events/events-c/event-test.c
b/examples/domain-events/events-c/event-test.c
index 09ec6aa..046c36e 100644
--- a/examples/domain-events/events-c/event-test.c
+++ b/examples/domain-events/events-c/event-test.c
@@ -474,7 +474,11 @@ int main(int argc, char **argv)
err && err->message ? err->message: "Unknown
error");
}
- virEventRegisterDefaultImpl();
+ if(0 != virEventRegisterDefaultImpl()) {
+ virErrorPtr err = virGetLastError();
+ fprintf(stderr, "Failed to register event implementation: %s\n",
+ err && err->message ? err->message: "Unknown
error");
+ }
virConnectPtr dconn = NULL;
dconn = virConnectOpenAuth(argc > 1 ? argv[1] : NULL,
--
1.7.10.4
4:21 a.m.
New subject: [libvirt] [PATCH 2/2] dom event example: Add error check to impl call
On 09.05.2013 23:17, Jesse J. Cook wrote:
From: "Jesse J. Cook" <jesse.j.cook(a)member.fsf.org>
Added error checking to virEventRegisterDefaultImpl call for consistency.
---
examples/domain-events/events-c/event-test.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/examples/domain-events/events-c/event-test.c
b/examples/domain-events/events-c/event-test.c
index 09ec6aa..046c36e 100644
--- a/examples/domain-events/events-c/event-test.c
+++ b/examples/domain-events/events-c/event-test.c
@@ -474,7 +474,11 @@ int main(int argc, char **argv)
err && err->message ? err->message: "Unknown
error");
}
- virEventRegisterDefaultImpl();
+ if(0 != virEventRegisterDefaultImpl()) {
We tend to write it vice versa. Moreover, there should be a space between 'if' and
'(':
if (virEventRegisterDefaultImpl() < 0) {
+ virErrorPtr err = virGetLastError();
But here is it perfectly safe to call virGetLastError() because the only way we could get
here
is where virInitialize reported success.
+ fprintf(stderr, "Failed to register event
implementation: %s\n",
+ err && err->message ? err->message: "Unknown
error");
Again, we should return -1 here.
+ }
virConnectPtr dconn = NULL;
dconn = virConnectOpenAuth(argc > 1 ? argv[1] : NULL,
ACK with this squashed in:
diff --git a/examples/domain-events/events-c/event-test.c
b/examples/domain-events/events-c/event-test.c
index bee3f78..301caad 100644
--- a/examples/domain-events/events-c/event-test.c
+++ b/examples/domain-events/events-c/event-test.c
@@ -473,10 +473,11 @@ int main(int argc, char **argv)
return -1;
}
- if(0 != virEventRegisterDefaultImpl()) {
+ if (virEventRegisterDefaultImpl() < 0) {
virErrorPtr err = virGetLastError();
fprintf(stderr, "Failed to register event implementation: %s\n",
err && err->message ? err->message: "Unknown
error");
+ return -1;
}
virConnectPtr dconn = NULL;
Michal
4:21 a.m.
On 09.05.2013 23:17, Jesse J. Cook wrote:
From: "Jesse J. Cook" <jcook(a)camber.com>
The example program makes a call to virEventRegisterDefaultImpl before calling
virConnectOpen without a call to virInitialize. Interestingly enough, the
example code works. However, once you introduce a call to g_string_new it
breaks. This can result in unintentional misuse of the API.
Relates to: Red Hat Bugzilla – Bug 961155
Jesse J. Cook (2):
dom event example: init before register event impl
dom event example: Add error check to impl call
examples/domain-events/events-c/event-test.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
I've squashed in both fixes and pushed.
Michal
4215
days inactive
4216
days old
5 comments
2 participants
participants (2)
-
Jesse J. Cook -
Michal Privoznik