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esx: Fix race condition in esxVI_EnsureSession

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When the session has expired then multiple threads can race while
reestablishing it.

This race condition is not that critical as it requires a special usage
pattern to be triggered. It can only happen when an application doesn't
do API calls for quite some time (the session expires after 30 min
inactivity) and then multiple threads doing simultaneous API calls and
end up doing simultaneous calls to esxVI_EnsureSession.
This commit is contained in:
Matthias Bolte 2011-05-01 21:57:43 +02:00
parent c256542e76
commit 6bf31327c6
2 changed files with 38 additions and 13 deletions
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47
src/esx/esx_vi.c
View File

@ -603,6 +603,10 @@ ESX_VI__TEMPLATE__ALLOC(Context)
/* esxVI_Context_Free */
ESX_VI__TEMPLATE__FREE(Context,
{
if (item->sessionLock != NULL) {
virMutexDestroy(item->sessionLock);
}
esxVI_CURL_Free(&item->curl);
VIR_FREE(item->url);
VIR_FREE(item->ipAddress);
@ -610,6 +614,7 @@ ESX_VI__TEMPLATE__FREE(Context,
VIR_FREE(item->password);
esxVI_ServiceContent_Free(&item->service);
esxVI_UserSession_Free(&item->session);
VIR_FREE(item->sessionLock);
esxVI_Datacenter_Free(&item->datacenter);
esxVI_ComputeResource_Free(&item->computeResource);
esxVI_HostSystem_Free(&item->hostSystem);
@ -642,6 +647,17 @@ esxVI_Context_Connect(esxVI_Context *ctx, const char *url,
return -1;
}
if (VIR_ALLOC(ctx->sessionLock) < 0) {
virReportOOMError();
return -1;
}
if (virMutexInit(ctx->sessionLock) < 0) {
ESX_VI_ERROR(VIR_ERR_INTERNAL_ERROR, "%s",
_("Could not initialize session mutex"));
return -1;
}
if (esxVI_RetrieveServiceContent(ctx, &ctx->service) < 0) {
return -1;
}
@ -1548,11 +1564,18 @@ esxVI_EnsureSession(esxVI_Context *ctx)
esxVI_DynamicProperty *dynamicProperty = NULL;
esxVI_UserSession *currentSession = NULL;
if (ctx->session == NULL) {
ESX_VI_ERROR(VIR_ERR_INTERNAL_ERROR, "%s", _("Invalid call"));
if (ctx->sessionLock == NULL) {
ESX_VI_ERROR(VIR_ERR_INTERNAL_ERROR, "%s", _("Invalid call, no mutex"));
return -1;
}
virMutexLock(ctx->sessionLock);
if (ctx->session == NULL) {
ESX_VI_ERROR(VIR_ERR_INTERNAL_ERROR, "%s", _("Invalid call, no session"));
goto cleanup;
}
if (ctx->hasSessionIsActive) {
/*
* Use SessionIsActive to check if there is an active session for this
@ -1560,7 +1583,7 @@ esxVI_EnsureSession(esxVI_Context *ctx)
*/
if (esxVI_SessionIsActive(ctx, ctx->session->key,
ctx->session->userName, &active) < 0) {
return -1;
goto cleanup;
}
if (active != esxVI_Boolean_True) {
@ -1568,11 +1591,9 @@ esxVI_EnsureSession(esxVI_Context *ctx)
if (esxVI_Login(ctx, ctx->username, ctx->password, NULL,
&ctx->session) < 0) {
return -1;
goto cleanup;
}
}
return 0;
} else {
/*
* Query the session manager for the current session of this connection
@ -1614,16 +1635,18 @@ esxVI_EnsureSession(esxVI_Context *ctx)
"last login"));
goto cleanup;
}
}
result = 0;
result = 0;
cleanup:
esxVI_String_Free(&propertyNameList);
esxVI_ObjectContent_Free(&sessionManager);
esxVI_UserSession_Free(&currentSession);
virMutexUnlock(ctx->sessionLock);
return result;
}
esxVI_String_Free(&propertyNameList);
esxVI_ObjectContent_Free(&sessionManager);
esxVI_UserSession_Free(&currentSession);
return result;
}

4
src/esx/esx_vi.h
View File

@ -185,6 +185,7 @@ int esxVI_SharedCURL_Remove(esxVI_SharedCURL *shared, esxVI_CURL *curl);
*/
struct _esxVI_Context {
/* All members are used read-only after esxVI_Context_Connect ... */
esxVI_CURL *curl;
char *url;
char *ipAddress;
@ -193,7 +194,8 @@ struct _esxVI_Context {
esxVI_ServiceContent *service;
esxVI_APIVersion apiVersion;
esxVI_ProductVersion productVersion;
esxVI_UserSession *session;
esxVI_UserSession *session; /* ... except the session ... */
virMutexPtr sessionLock; /* ... that is protected by this mutex */
esxVI_Datacenter *datacenter;
esxVI_ComputeResource *computeResource;
esxVI_HostSystem *hostSystem;