libvirt/src/parallels/parallels_utils.c

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/*
* parallels_utils.c: core driver functions for managing
* Parallels Cloud Server hosts
*
* Copyright (C) 2012 Parallels, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; If not, see
* <http://www.gnu.org/licenses/>.
*
*/
#include <config.h>
#include <stdarg.h>
#include "vircommand.h"
#include "virerror.h"
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#include "viralloc.h"
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#include "virjson.h"
#include "parallels_utils.h"
#include "virstring.h"
#include "datatypes.h"
#define VIR_FROM_THIS VIR_FROM_PARALLELS
/**
* vzDomObjFromDomain:
* @domain: Domain pointer that has to be looked up
*
* This function looks up @domain and returns the appropriate virDomainObjPtr
* that has to be unlocked by virObjectUnlock().
*
* Returns the domain object without incremented reference counter which is locked
* on success, NULL otherwise.
*/
virDomainObjPtr
vzDomObjFromDomain(virDomainPtr domain)
{
virDomainObjPtr vm;
vzConnPtr privconn = domain->conn->privateData;
char uuidstr[VIR_UUID_STRING_BUFLEN];
vm = virDomainObjListFindByUUID(privconn->domains, domain->uuid);
if (!vm) {
virUUIDFormat(domain->uuid, uuidstr);
virReportError(VIR_ERR_NO_DOMAIN,
_("no domain with matching uuid '%s' (%s)"),
uuidstr, domain->name);
return NULL;
}
return vm;
}
parallels: add block device statistics to driver Statistics provided through PCS SDK. As we have only async interface in SDK we need to be subscribed to statistics in order to get it. Trivial solution on every stat request to subscribe, wait event and then unsubscribe will lead to significant delays in case of a number of successive requests, as the event will be delivered on next PCS server notify cycle. On the other hand we don't want to keep unnesessary subscribtion. So we take an hibrid solution to subcsribe on first request and then keep a subscription while requests are active. We populate cache of statistics on subscribtion events and use this cache to serve libvirts requests. * Cache details. Cache is just handle to last arrived event, we call this cache as if this handle is valid it is used to serve synchronous statistics requests. We use number of successive events count to detect that user lost interest to statistics. We reset this count to 0 on every request. If more than PARALLELS_STATISTICS_DROP_COUNT successive events arrive we unsubscribe. Special value of -1 of this counter is used to differentiate between subscribed/unsubscribed state to protect from delayed events. Values of PARALLELS_STATISTICS_DROP_COUNT and PARALLELS_STATISTICS_TIMEOUT are just drop-ins, choosen without special consideration. * Thread safety issues Use parallelsDomObjFromDomainRef in parallelsDomainBlockStats as we could wait on domain lock down on stack in prlsdkGetStatsParam and if we won't keep reference we could get dangling pointer on return from wait. Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy@parallels.com>
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/**
* vzDomObjFromDomainRef:
parallels: add block device statistics to driver Statistics provided through PCS SDK. As we have only async interface in SDK we need to be subscribed to statistics in order to get it. Trivial solution on every stat request to subscribe, wait event and then unsubscribe will lead to significant delays in case of a number of successive requests, as the event will be delivered on next PCS server notify cycle. On the other hand we don't want to keep unnesessary subscribtion. So we take an hibrid solution to subcsribe on first request and then keep a subscription while requests are active. We populate cache of statistics on subscribtion events and use this cache to serve libvirts requests. * Cache details. Cache is just handle to last arrived event, we call this cache as if this handle is valid it is used to serve synchronous statistics requests. We use number of successive events count to detect that user lost interest to statistics. We reset this count to 0 on every request. If more than PARALLELS_STATISTICS_DROP_COUNT successive events arrive we unsubscribe. Special value of -1 of this counter is used to differentiate between subscribed/unsubscribed state to protect from delayed events. Values of PARALLELS_STATISTICS_DROP_COUNT and PARALLELS_STATISTICS_TIMEOUT are just drop-ins, choosen without special consideration. * Thread safety issues Use parallelsDomObjFromDomainRef in parallelsDomainBlockStats as we could wait on domain lock down on stack in prlsdkGetStatsParam and if we won't keep reference we could get dangling pointer on return from wait. Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy@parallels.com>
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* @domain: Domain pointer that has to be looked up
*
* This function looks up @domain and returns the appropriate virDomainObjPtr
* that has to be released by calling virDomainObjEndAPI().
*
* Returns the domain object with incremented reference counter which is locked
* on success, NULL otherwise.
*/
virDomainObjPtr
vzDomObjFromDomainRef(virDomainPtr domain)
parallels: add block device statistics to driver Statistics provided through PCS SDK. As we have only async interface in SDK we need to be subscribed to statistics in order to get it. Trivial solution on every stat request to subscribe, wait event and then unsubscribe will lead to significant delays in case of a number of successive requests, as the event will be delivered on next PCS server notify cycle. On the other hand we don't want to keep unnesessary subscribtion. So we take an hibrid solution to subcsribe on first request and then keep a subscription while requests are active. We populate cache of statistics on subscribtion events and use this cache to serve libvirts requests. * Cache details. Cache is just handle to last arrived event, we call this cache as if this handle is valid it is used to serve synchronous statistics requests. We use number of successive events count to detect that user lost interest to statistics. We reset this count to 0 on every request. If more than PARALLELS_STATISTICS_DROP_COUNT successive events arrive we unsubscribe. Special value of -1 of this counter is used to differentiate between subscribed/unsubscribed state to protect from delayed events. Values of PARALLELS_STATISTICS_DROP_COUNT and PARALLELS_STATISTICS_TIMEOUT are just drop-ins, choosen without special consideration. * Thread safety issues Use parallelsDomObjFromDomainRef in parallelsDomainBlockStats as we could wait on domain lock down on stack in prlsdkGetStatsParam and if we won't keep reference we could get dangling pointer on return from wait. Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy@parallels.com>
2015-06-09 07:35:53 +00:00
{
virDomainObjPtr vm;
vzConnPtr privconn = domain->conn->privateData;
parallels: add block device statistics to driver Statistics provided through PCS SDK. As we have only async interface in SDK we need to be subscribed to statistics in order to get it. Trivial solution on every stat request to subscribe, wait event and then unsubscribe will lead to significant delays in case of a number of successive requests, as the event will be delivered on next PCS server notify cycle. On the other hand we don't want to keep unnesessary subscribtion. So we take an hibrid solution to subcsribe on first request and then keep a subscription while requests are active. We populate cache of statistics on subscribtion events and use this cache to serve libvirts requests. * Cache details. Cache is just handle to last arrived event, we call this cache as if this handle is valid it is used to serve synchronous statistics requests. We use number of successive events count to detect that user lost interest to statistics. We reset this count to 0 on every request. If more than PARALLELS_STATISTICS_DROP_COUNT successive events arrive we unsubscribe. Special value of -1 of this counter is used to differentiate between subscribed/unsubscribed state to protect from delayed events. Values of PARALLELS_STATISTICS_DROP_COUNT and PARALLELS_STATISTICS_TIMEOUT are just drop-ins, choosen without special consideration. * Thread safety issues Use parallelsDomObjFromDomainRef in parallelsDomainBlockStats as we could wait on domain lock down on stack in prlsdkGetStatsParam and if we won't keep reference we could get dangling pointer on return from wait. Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy@parallels.com>
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char uuidstr[VIR_UUID_STRING_BUFLEN];
vm = virDomainObjListFindByUUIDRef(privconn->domains, domain->uuid);
if (!vm) {
virUUIDFormat(domain->uuid, uuidstr);
virReportError(VIR_ERR_NO_DOMAIN,
_("no domain with matching uuid '%s' (%s)"),
uuidstr, domain->name);
return NULL;
}
return vm;
}
static int
vzDoCmdRun(char **outbuf, const char *binary, va_list list)
{
virCommandPtr cmd = virCommandNewVAList(binary, list);
int ret = -1;
if (outbuf)
virCommandSetOutputBuffer(cmd, outbuf);
if (virCommandRun(cmd, NULL) < 0)
goto cleanup;
ret = 0;
cleanup:
virCommandFree(cmd);
if (ret && outbuf)
VIR_FREE(*outbuf);
return ret;
}
/*
* Run command and parse its JSON output, return
* pointer to virJSONValue or NULL in case of error.
*/
virJSONValuePtr
vzParseOutput(const char *binary, ...)
{
char *outbuf;
virJSONValuePtr jobj = NULL;
va_list list;
int ret;
va_start(list, binary);
ret = vzDoCmdRun(&outbuf, binary, list);
va_end(list);
if (ret)
return NULL;
jobj = virJSONValueFromString(outbuf);
if (!jobj)
virReportError(VIR_ERR_INTERNAL_ERROR,
_("invalid output from prlctl: %s"), outbuf);
VIR_FREE(outbuf);
return jobj;
}
/*
* Run command and return its output, pointer to
* buffer or NULL in case of error. Caller os responsible
* for freeing the buffer.
*/
char *
vzGetOutput(const char *binary, ...)
{
char *outbuf;
va_list list;
int ret;
va_start(list, binary);
ret = vzDoCmdRun(&outbuf, binary, list);
va_end(list);
if (ret)
return NULL;
return outbuf;
}
/*
* Run prlctl command and check for errors
*
* Return value is 0 in case of success, else - -1
*/
int
vzCmdRun(const char *binary, ...)
{
int ret;
va_list list;
va_start(list, binary);
ret = vzDoCmdRun(NULL, binary, list);
va_end(list);
return ret;
}
/*
* Return new file path in malloced string created by
* concatenating first and second function arguments.
*/
char *
vzAddFileExt(const char *path, const char *ext)
{
char *new_path = NULL;
size_t len = strlen(path) + strlen(ext) + 1;
if (VIR_ALLOC_N(new_path, len) < 0)
return NULL;
if (!virStrcpy(new_path, path, len)) {
VIR_FREE(new_path);
return NULL;
}
strcat(new_path, ext);
return new_path;
}