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Thread local error reporting

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This commit is contained in:
Daniel P. Berrange 2009-01-20 12:01:45 +00:00
parent c790f6d25e
commit ead04dcbe8
6 changed files with 1935 additions and 509 deletions
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17
ChangeLog
View File

@ -1,3 +1,20 @@
Tue Jan 20 12:01:53 GMT 2009 Daniel P. Berrange <berrange@redhat.com>
Thread local error handling
* src/datatypes.c: Don't reference global error object directly
now that it is thread-local. Avoid passing 'conn' arg to error
routines if we just determined that the pointer is invalid
* src/datatypes.h: Add note about rules for locking when using
virConnectPtr members
* src/libvirt.c: Initialize error handling routines at startup.
Adapt driver API methods to reset last error upon entry, and
copy the global thread local error to the per-connection error
upon exit
* src/virterror.c, src/virterror_internal.h: Store the global
error object in a thread local variable. Provide a API to copy
the global error into a per-connection error object. Add an
initialization routine to setup the thread local
Tue Jan 20 11:43:53 GMT 2009 Daniel P. Berrange <berrange@redhat.com>
* src/remote_internal.c: Disable event watch when doing an

31
src/datatypes.c
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@ -195,8 +195,6 @@ virReleaseConnect(virConnectPtr conn) {
virHashFree(conn->nodeDevices, (virHashDeallocator) virNodeDeviceFree);
virResetError(&conn->err);
if (virLastErr.conn == conn)
virLastErr.conn = NULL;
xmlFreeURI(conn->uri);
@ -219,7 +217,7 @@ virUnrefConnect(virConnectPtr conn) {
int refs;
if ((!VIR_IS_CONNECT(conn))) {
virLibConnError(conn, VIR_ERR_INVALID_ARG, __FUNCTION__);
virLibConnError(NULL, VIR_ERR_INVALID_ARG, __FUNCTION__);
return(-1);
}
virMutexLock(&conn->lock);
@ -253,7 +251,7 @@ virGetDomain(virConnectPtr conn, const char *name, const unsigned char *uuid) {
virDomainPtr ret = NULL;
if ((!VIR_IS_CONNECT(conn)) || (name == NULL) || (uuid == NULL)) {
virLibConnError(conn, VIR_ERR_INVALID_ARG, __FUNCTION__);
virLibConnError(NULL, VIR_ERR_INVALID_ARG, __FUNCTION__);
return(NULL);
}
virMutexLock(&conn->lock);
@ -323,10 +321,6 @@ virReleaseDomain(virDomainPtr domain) {
virLibConnError(conn, VIR_ERR_INTERNAL_ERROR,
_("domain missing from connection hash table"));
if (conn->err.dom == domain)
conn->err.dom = NULL;
if (virLastErr.dom == domain)
virLastErr.dom = NULL;
domain->magic = -1;
domain->id = -1;
VIR_FREE(domain->name);
@ -358,7 +352,7 @@ virUnrefDomain(virDomainPtr domain) {
int refs;
if (!VIR_IS_CONNECTED_DOMAIN(domain)) {
virLibConnError(domain->conn, VIR_ERR_INVALID_ARG, __FUNCTION__);
virLibConnError(NULL, VIR_ERR_INVALID_ARG, __FUNCTION__);
return(-1);
}
virMutexLock(&domain->conn->lock);
@ -393,7 +387,7 @@ virGetNetwork(virConnectPtr conn, const char *name, const unsigned char *uuid) {
virNetworkPtr ret = NULL;
if ((!VIR_IS_CONNECT(conn)) || (name == NULL) || (uuid == NULL)) {
virLibConnError(conn, VIR_ERR_INVALID_ARG, __FUNCTION__);
virLibConnError(NULL, VIR_ERR_INVALID_ARG, __FUNCTION__);
return(NULL);
}
virMutexLock(&conn->lock);
@ -459,11 +453,6 @@ virReleaseNetwork(virNetworkPtr network) {
virLibConnError(conn, VIR_ERR_INTERNAL_ERROR,
_("network missing from connection hash table"));
if (conn->err.net == network)
conn->err.net = NULL;
if (virLastErr.net == network)
virLastErr.net = NULL;
network->magic = -1;
VIR_FREE(network->name);
VIR_FREE(network);
@ -494,7 +483,7 @@ virUnrefNetwork(virNetworkPtr network) {
int refs;
if (!VIR_IS_CONNECTED_NETWORK(network)) {
virLibConnError(network->conn, VIR_ERR_INVALID_ARG, __FUNCTION__);
virLibConnError(NULL, VIR_ERR_INVALID_ARG, __FUNCTION__);
return(-1);
}
virMutexLock(&network->conn->lock);
@ -530,7 +519,7 @@ virGetStoragePool(virConnectPtr conn, const char *name, const unsigned char *uui
virStoragePoolPtr ret = NULL;
if ((!VIR_IS_CONNECT(conn)) || (name == NULL) || (uuid == NULL)) {
virLibConnError(conn, VIR_ERR_INVALID_ARG, __FUNCTION__);
virLibConnError(NULL, VIR_ERR_INVALID_ARG, __FUNCTION__);
return(NULL);
}
virMutexLock(&conn->lock);
@ -627,7 +616,7 @@ virUnrefStoragePool(virStoragePoolPtr pool) {
int refs;
if (!VIR_IS_CONNECTED_STORAGE_POOL(pool)) {
virLibConnError(pool->conn, VIR_ERR_INVALID_ARG, __FUNCTION__);
virLibConnError(NULL, VIR_ERR_INVALID_ARG, __FUNCTION__);
return(-1);
}
virMutexLock(&pool->conn->lock);
@ -664,7 +653,7 @@ virGetStorageVol(virConnectPtr conn, const char *pool, const char *name, const c
virStorageVolPtr ret = NULL;
if ((!VIR_IS_CONNECT(conn)) || (name == NULL) || (key == NULL)) {
virLibConnError(conn, VIR_ERR_INVALID_ARG, __FUNCTION__);
virLibConnError(NULL, VIR_ERR_INVALID_ARG, __FUNCTION__);
return(NULL);
}
virMutexLock(&conn->lock);
@ -765,7 +754,7 @@ virUnrefStorageVol(virStorageVolPtr vol) {
int refs;
if (!VIR_IS_CONNECTED_STORAGE_VOL(vol)) {
virLibConnError(vol->conn, VIR_ERR_INVALID_ARG, __FUNCTION__);
virLibConnError(NULL, VIR_ERR_INVALID_ARG, __FUNCTION__);
return(-1);
}
virMutexLock(&vol->conn->lock);
@ -801,7 +790,7 @@ virGetNodeDevice(virConnectPtr conn, const char *name)
virNodeDevicePtr ret = NULL;
if ((!VIR_IS_CONNECT(conn)) || (name == NULL)) {
virLibConnError(conn, VIR_ERR_INVALID_ARG, __FUNCTION__);
virLibConnError(NULL, VIR_ERR_INVALID_ARG, __FUNCTION__);
return(NULL);
}
virMutexLock(&conn->lock);

15
src/datatypes.h
View File

@ -95,6 +95,10 @@
* Internal structure associated to a connection
*/
struct _virConnect {
/* All the variables from here, until the 'lock' declaration
* are setup at time of connection open, and never changed
* since. Thus no need to lock when accessing them
*/
unsigned int magic; /* specific value to check */
int flags; /* a set of connection flags */
xmlURIPtr uri; /* connection URI */
@ -114,11 +118,6 @@ struct _virConnect {
void * storagePrivateData;
void * devMonPrivateData;
/* Per-connection error. */
virError err; /* the last error */
virErrorFunc handler; /* associated handlet */
void *userData; /* the user data */
/*
* The lock mutex must be acquired before accessing/changing
* any of members following this point, or changing the ref
@ -126,6 +125,12 @@ struct _virConnect {
* this connection
*/
virMutex lock;
/* Per-connection error. */
virError err; /* the last error */
virErrorFunc handler; /* associated handlet */
void *userData; /* the user data */
virHashTablePtr domains; /* hash table for known domains */
virHashTablePtr networks; /* hash table for known domains */
virHashTablePtr storagePools;/* hash table for known storage pools */

2118
src/libvirt.c
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File diff suppressed because it is too large Load Diff

258
src/virterror.c
View File

@ -18,11 +18,11 @@
#include "virterror_internal.h"
#include "datatypes.h"
#include "logging.h"
#include "memory.h"
#include "threads.h"
virThreadLocal virLastErr;
virError virLastErr = /* the last error */
{ .code = 0, .domain = 0, .message = NULL, .level = VIR_ERR_NONE,
.conn = NULL, .dom = NULL, .str1 = NULL, .str2 = NULL, .str3 = NULL,
.int1 = 0, .int2 = 0, .net = NULL };
virErrorFunc virErrorHandler = NULL; /* global error handler */
void *virUserData = NULL; /* associated data */
@ -154,28 +154,118 @@ static const char *virErrorDomainName(virErrorDomain domain) {
return(dom);
}
/*
* Internal helper that is called when a thread exits, to
* release the error object stored in the thread local
*/
static void
virLastErrFreeData(void *data)
{
virErrorPtr err = data;
if (!err)
return;
virResetError(err);
VIR_FREE(err);
}
int
virErrorInitialize(void)
{
return virThreadLocalInit(&virLastErr, virLastErrFreeData);
}
/*
* Internal helper to ensure a generic error code is stored
* in case where API returns failure, but forgot to set an
* error
*/
static void
virErrorGenericFailure(virErrorPtr err)
{
err->code = VIR_ERR_INTERNAL_ERROR;
err->domain = VIR_FROM_NONE;
err->level = VIR_ERR_ERROR;
err->message = strdup(_("Unknown failure"));
}
/*
* Internal helper to perform a deep copy of the an error
*/
static int
virCopyError(virErrorPtr from,
virErrorPtr to)
{
int ret = 0;
if (!to)
return 0;
virResetError(to);
if (!from)
return 0;
to->code = from->code;
to->domain = from->domain;
to->level = from->level;
if (from->message && !(to->message = strdup(from->message)))
ret = -1;
if (from->str1 && !(to->str1 = strdup(from->str1)))
ret = -1;
if (from->str2 && !(to->str2 = strdup(from->str2)))
ret = -1;
if (from->str3 && !(to->str3 = strdup(from->str3)))
ret = -1;
to->int1 = from->int1;
to->int2 = from->int2;
/*
* Delibrately not setting 'conn', 'dom', 'net' references
*/
return ret;
}
static virErrorPtr
virLastErrorObject(void)
{
virErrorPtr err;
err = virThreadLocalGet(&virLastErr);
if (!err) {
if (VIR_ALLOC(err) < 0)
return NULL;
virThreadLocalSet(&virLastErr, err);
}
return err;
}
/**
* virGetLastError:
*
* Provide a pointer to the last error caught at the library level
* Simpler but may not be suitable for multithreaded accesses, in which
* case use virCopyLastError()
*
* The error object is kept in thread local storage, so separate
* threads can safely access this concurrently.
*
* Returns a pointer to the last error or NULL if none occurred.
*/
virErrorPtr
virGetLastError(void)
{
if (virLastErr.code == VIR_ERR_OK)
return (NULL);
return (&virLastErr);
virErrorPtr err = virLastErrorObject();
if (!err || err->code == VIR_ERR_OK)
return NULL;
return err;
}
/*
/**
* virCopyLastError:
* @to: target to receive the copy
*
* Copy the content of the last error caught at the library level
*
* The error object is kept in thread local storage, so separate
* threads can safely access this concurrently.
*
* One will need to free the result with virResetError()
*
* Returns 0 if no error was found and the error code otherwise and -1 in case
@ -184,12 +274,14 @@ virGetLastError(void)
int
virCopyLastError(virErrorPtr to)
{
if (to == NULL)
return (-1);
if (virLastErr.code == VIR_ERR_OK)
return (0);
memcpy(to, &virLastErr, sizeof(virError));
return (virLastErr.code);
virErrorPtr err = virLastErrorObject();
/* We can't guarentee caller has initialized it to zero */
memset(to, 0, sizeof(*to));
if (err)
virCopyError(err, to);
else
virResetError(to);
return to->code;
}
/**
@ -210,15 +302,22 @@ virResetError(virErrorPtr err)
memset(err, 0, sizeof(virError));
}
/**
* virResetLastError:
*
* Reset the last error caught at the library level.
*
* The error object is kept in thread local storage, so separate
* threads can safely access this concurrently, only resetting
* their own error object.
*/
void
virResetLastError(void)
{
virResetError(&virLastErr);
virErrorPtr err = virLastErrorObject();
if (err)
virResetError(err);
}
/**
@ -226,8 +325,20 @@ virResetLastError(void)
* @conn: pointer to the hypervisor connection
*
* Provide a pointer to the last error caught on that connection
* Simpler but may not be suitable for multithreaded accesses, in which
* case use virConnCopyLastError()
*
* This method is not protected against access from multiple
* threads. In a multi-threaded application, always use the
* global virGetLastError() API which is backed by thread
* local storage.
*
* If the connection object was discovered to be invalid by
* an API call, then the error will be reported against the
* global error object.
*
* Since 0.6.0, all errors reported in the per-connection object
* are also duplicated in the global error object. As such an
* application can always use virGetLastError(). This method
* remains for backwards compatability.
*
* Returns a pointer to the last error or NULL if none occurred.
*/
@ -235,8 +346,8 @@ virErrorPtr
virConnGetLastError(virConnectPtr conn)
{
if (conn == NULL)
return (NULL);
return (&conn->err);
return NULL;
return &conn->err;
}
/**
@ -245,6 +356,21 @@ virConnGetLastError(virConnectPtr conn)
* @to: target to receive the copy
*
* Copy the content of the last error caught on that connection
*
* This method is not protected against access from multiple
* threads. In a multi-threaded application, always use the
* global virGetLastError() API which is backed by thread
* local storage.
*
* If the connection object was discovered to be invalid by
* an API call, then the error will be reported against the
* global error object.
*
* Since 0.6.0, all errors reported in the per-connection object
* are also duplicated in the global error object. As such an
* application can always use virGetLastError(). This method
* remains for backwards compatability.
*
* One will need to free the result with virResetError()
*
* Returns 0 if no error was found and the error code otherwise and -1 in case
@ -253,20 +379,27 @@ virConnGetLastError(virConnectPtr conn)
int
virConnCopyLastError(virConnectPtr conn, virErrorPtr to)
{
/* We can't guarentee caller has initialized it to zero */
memset(to, 0, sizeof(*to));
if (conn == NULL)
return (-1);
if (to == NULL)
return (-1);
return -1;
virMutexLock(&conn->lock);
if (conn->err.code == VIR_ERR_OK)
return (0);
memcpy(to, &conn->err, sizeof(virError));
return (conn->err.code);
virResetError(to);
else
virCopyError(&conn->err, to);
virMutexUnlock(&conn->lock);
return to->code;
}
/**
* virConnResetLastError:
* @conn: pointer to the hypervisor connection
*
* The error object is kept in thread local storage, so separate
* threads can safely access this concurrently.
*
* Reset the last error caught on that connection
*/
void
@ -274,7 +407,9 @@ virConnResetLastError(virConnectPtr conn)
{
if (conn == NULL)
return;
virMutexLock(&conn->lock);
virResetError(&conn->err);
virMutexUnlock(&conn->lock);
}
/**
@ -309,8 +444,10 @@ virConnSetErrorFunc(virConnectPtr conn, void *userData,
{
if (conn == NULL)
return;
virMutexLock(&conn->lock);
conn->handler = handler;
conn->userData = userData;
virMutexUnlock(&conn->lock);
}
/**
@ -357,6 +494,44 @@ virDefaultErrorFunc(virErrorPtr err)
dom, lvl, domain, network, err->message);
}
/*
* Internal helper to ensure the global error object
* is initialized with a generic message if not already
* set.
*/
void
virSetGlobalError(void)
{
virErrorPtr err = virLastErrorObject();
if (err && err->code == VIR_ERR_OK)
virErrorGenericFailure(err);
}
/*
* Internal helper to ensure the connection error object
* is initialized from the global object.
*/
void
virSetConnError(virConnectPtr conn)
{
virErrorPtr err = virLastErrorObject();
if (err && err->code == VIR_ERR_OK)
virErrorGenericFailure(err);
if (conn) {
virMutexLock(&conn->lock);
if (err)
virCopyError(err, &conn->err);
else
virErrorGenericFailure(&conn->err);
virMutexUnlock(&conn->lock);
}
}
/**
* virRaiseError:
* @conn: the connection to the hypervisor if available
@ -377,16 +552,29 @@ virDefaultErrorFunc(virErrorPtr err)
* immediately if a callback is found and store it for later handling.
*/
void
virRaiseError(virConnectPtr conn, virDomainPtr dom, virNetworkPtr net,
virRaiseError(virConnectPtr conn,
virDomainPtr dom ATTRIBUTE_UNUSED,
virNetworkPtr net ATTRIBUTE_UNUSED,
int domain, int code, virErrorLevel level,
const char *str1, const char *str2, const char *str3,
int int1, int int2, const char *msg, ...)
{
virErrorPtr to = &virLastErr;
virErrorPtr to;
void *userData = virUserData;
virErrorFunc handler = virErrorHandler;
char *str;
/*
* All errors are recorded in thread local storage
* For compatability, public API calls will copy them
* to the per-connection error object when neccessary
*/
to = virLastErrorObject();
if (!to)
return; /* Hit OOM allocating thread error object, sod all we can do now */
virResetError(to);
if (code == VIR_ERR_OK)
return;
@ -394,11 +582,12 @@ virRaiseError(virConnectPtr conn, virDomainPtr dom, virNetworkPtr net,
* try to find the best place to save and report the error
*/
if (conn != NULL) {
to = &conn->err;
virMutexLock(&conn->lock);
if (conn->handler != NULL) {
handler = conn->handler;
userData = conn->userData;
}
virMutexUnlock(&conn->lock);
}
/*
@ -421,9 +610,10 @@ virRaiseError(virConnectPtr conn, virDomainPtr dom, virNetworkPtr net,
* Save the information about the error
*/
virResetError(to);
to->conn = conn;
to->dom = dom;
to->net = net;
/*
* Delibrately not setting conn, dom & net fields since
* they're utterly unsafe
*/
to->domain = domain;
to->code = code;
to->message = str;
@ -813,3 +1003,5 @@ void virReportErrorHelper(virConnectPtr conn, int domcode, int errcode,
virerr, errorMessage, NULL, -1, -1, virerr, errorMessage);
}

5
src/virterror_internal.h
View File

@ -24,7 +24,6 @@
#include "internal.h"
extern virError virLastErr;
extern virErrorFunc virErrorHandler;
extern void *virUserData;
@ -33,6 +32,7 @@ extern void *virUserData;
* API for error handling *
* *
************************************************************************/
int virErrorInitialize(void);
void virRaiseError(virConnectPtr conn,
virDomainPtr dom,
virNetworkPtr net,
@ -53,4 +53,7 @@ void virReportErrorHelper(virConnectPtr conn, int domcode, int errcode,
ATTRIBUTE_FORMAT(printf, 7, 8);
void virSetGlobalError(void);
void virSetConnError(virConnectPtr conn);
#endif