[libvirt] [PATCH 1/3] qemu_monitor: introduce new function to get QOM path
John Ferlan
jferlan at redhat.com
Mon Dec 15 23:54:59 UTC 2014
On 12/11/2014 10:42 AM, Pavel Hrdina wrote:
> The search is done recursively only through QOM object that has a type
> prefixed with "child<" as this indicate that the QOM is a parent for
> other QOM objects.
>
> The usage is that you give known device name with starting path where to
> search.
>
> Signed-off-by: Pavel Hrdina <phrdina at redhat.com>
> ---
> src/qemu/qemu_monitor.c | 173 ++++++++++++++++++++++++++++--------------------
> 1 file changed, 102 insertions(+), 71 deletions(-)
>
> diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c
> index c9c84f9..ee4460f 100644
> --- a/src/qemu/qemu_monitor.c
> +++ b/src/qemu/qemu_monitor.c
> @@ -1008,22 +1008,90 @@ qemuMonitorSetOptions(qemuMonitorPtr mon, virJSONValuePtr options)
> mon->options = options;
> }
>
> -/* Search the qom objects for the balloon driver object by it's known name
> - * of "virtio-balloon-pci". The entry for the driver will be found in the
> - * returned 'type' field using the syntax "child<virtio-balloon-pci>".
> - *
> - * Once found, check the entry to ensure it has the correct property listed.
> - * If it does not, then obtaining statistics from qemu will not be possible.
> - * This feature was added to qemu 1.5.
> +
> +/**
> + * Search the qom objects by it's known name. The name is compared against
> + * filed 'type' formatted as 'link<%name>'.
> *
> * This procedure will be call recursively until found or the qom-list is
> * exhausted.
> *
> * Returns:
> *
> - * 1 - Found
> - * 0 - Not found still looking
> + * 0 - Found
> * -1 - Error bail out
> + * -2 - Not found
> + *
> + * NOTE: This assumes we have already called qemuDomainObjEnterMonitor()
> + */
> +static int
> +qemuMonitorFindObjectPath(qemuMonitorPtr mon,
> + const char *curpath,
> + const char *name,
> + char **path)
> +{
> + ssize_t i, npaths = 0;
> + int ret = -2;
> + char *nextpath = NULL;
> + char *type = NULL;
> + qemuMonitorJSONListPathPtr *paths = NULL;
> +
> + if (virAsprintf(&type, "link<%s>", name) < 0)
> + return -1;
> +
> + VIR_DEBUG("Searching for '%s' Object Path starting at '%s'", type, curpath);
> +
> + npaths = qemuMonitorJSONGetObjectListPaths(mon, curpath, &paths);
> + if (npaths < 0)
> + goto cleanup;
> +
> + for (i = 0; i < npaths && ret == -2; i++) {
> +
> + if (STREQ_NULLABLE(paths[i]->type, type)) {
> + VIR_DEBUG("Path to '%s' is '%s/%s'", type, curpath, paths[i]->name);
> + ret = 0;
> + if (virAsprintf(path, "%s/%s", curpath, paths[i]->name) < 0) {
> + *path = NULL;
> + ret = -1;
> + }
> + goto cleanup;
> + }
> +
> + /* Type entries that begin with "child<" are a branch that can be
> + * traversed looking for more entries
> + */
> + if (paths[i]->type && STRPREFIX(paths[i]->type, "child<")) {
> + if (virAsprintf(&nextpath, "%s/%s", curpath, paths[i]->name) < 0) {
> + ret = -1;
> + goto cleanup;
> + }
> +
> + ret = qemuMonitorFindObjectPath(mon, nextpath, name, path);
> + }
> + }
> +
> + cleanup:
> + for (i = 0; i < npaths; i++)
> + qemuMonitorJSONListPathFree(paths[i]);
> + VIR_FREE(paths);
> + VIR_FREE(nextpath);
> + VIR_FREE(type);
> + return ret;
> +}
> +
> +
NIT: You added a /** as the comment opener previously, but not here.
> +/* Search the qom objects for the balloon driver object by it's known name
> + * of "virtio-balloon-pci". The entry for the driver will be found by using
> + * function "qemuMonitorFindObjectPath".
> + *
> + * Once found, check the entry to ensure it has the correct property listed.
> + * If it does not, then obtaining statistics from QEMU will not be possible.
> + * This feature was added to QEMU 1.5.
> + *
> + * Returns:
> + *
> + * 0 - Found
> + * -1 - Not found or error
> *
> * NOTE: This assumes we have already called qemuDomainObjEnterMonitor()
> */
> @@ -1032,14 +1100,13 @@ qemuMonitorFindBalloonObjectPath(qemuMonitorPtr mon,
> virDomainObjPtr vm,
> const char *curpath)
> {
> - ssize_t i, j, npaths = 0, nprops = 0;
> - int ret = 0;
> - char *nextpath = NULL;
> - qemuMonitorJSONListPathPtr *paths = NULL;
> + ssize_t i, nprops = 0;
> + int ret = -1;
> + char *path = NULL;
> qemuMonitorJSONListPathPtr *bprops = NULL;
>
> if (mon->balloonpath) {
> - return 1;
> + return 0;
> } else if (mon->ballooninit) {
> virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> _("Cannot determine balloon device path"));
> @@ -1055,70 +1122,34 @@ qemuMonitorFindBalloonObjectPath(qemuMonitorPtr mon,
> return -1;
> }
>
> - VIR_DEBUG("Searching for Balloon Object Path starting at %s", curpath);
> -
> - npaths = qemuMonitorJSONGetObjectListPaths(mon, curpath, &paths);
> - if (npaths < 0)
> + if (qemuMonitorFindObjectPath(mon, curpath, "virtio-balloon-pci", &path) < 0)
> return -1;
>
> - for (i = 0; i < npaths && ret == 0; i++) {
> -
> - if (STREQ_NULLABLE(paths[i]->type, "link<virtio-balloon-pci>")) {
> - VIR_DEBUG("Path to <virtio-balloon-pci> is '%s/%s'",
> - curpath, paths[i]->name);
> - if (virAsprintf(&nextpath, "%s/%s", curpath, paths[i]->name) < 0) {
> - ret = -1;
> - goto cleanup;
> - }
> -
> - /* Now look at the each of the property entries to determine
> - * whether "guest-stats-polling-interval" exists. If not,
> - * then this version of qemu/kvm does not support the feature.
> - */
> - nprops = qemuMonitorJSONGetObjectListPaths(mon, nextpath, &bprops);
> - if (nprops < 0) {
> - ret = -1;
> - goto cleanup;
> - }
> -
> - for (j = 0; j < nprops; j++) {
> - if (STREQ(bprops[j]->name, "guest-stats-polling-interval")) {
> - VIR_DEBUG("Found Balloon Object Path %s", nextpath);
> - mon->balloonpath = nextpath;
> - nextpath = NULL;
> - ret = 1;
> - goto cleanup;
> - }
> - }
> -
> - /* If we get here, we found the path, but not the property */
> - virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> - _("Property 'guest-stats-polling-interval' "
> - "not found on memory balloon driver."));
> - ret = -1;
> + nprops = qemuMonitorJSONGetObjectListPaths(mon, path, &bprops);
> + if (nprops < 0)
> + goto cleanup;
> +
> + for (i = 0; i < nprops; i++) {
> + if (STREQ(bprops[i]->name, "guest-stats-polling-interval")) {
> + VIR_DEBUG("Found Balloon Object Path %s", path);
> + mon->balloonpath = path;
> + path = NULL;
> + ret = 0;
> goto cleanup;
> }
> -
> - /* Type entries that begin with "child<" are a branch that can be
> - * traversed looking for more entries
> - */
> - if (paths[i]->type && STRPREFIX(paths[i]->type, "child<")) {
> - if (virAsprintf(&nextpath, "%s/%s", curpath, paths[i]->name) < 0) {
> - ret = -1;
> - goto cleanup;
> - }
> - ret = qemuMonitorFindBalloonObjectPath(mon, vm, nextpath);
> - }
> }
>
> +
> + /* If we get here, we found the path, but not the property */
> + virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> + _("Property 'guest-stats-polling-interval' "
> + "not found on memory balloon driver."));
> +
> cleanup:
> - for (i = 0; i < npaths; i++)
> - qemuMonitorJSONListPathFree(paths[i]);
> - VIR_FREE(paths);
> - for (j = 0; j < nprops; j++)
> - qemuMonitorJSONListPathFree(bprops[j]);
> + for (i = 0; i < nprops; i++)
> + qemuMonitorJSONListPathFree(bprops[i]);
> VIR_FREE(bprops);
> - VIR_FREE(nextpath);
> + VIR_FREE(path);
> return ret;
> }
>
> @@ -1660,7 +1691,7 @@ int qemuMonitorSetMemoryStatsPeriod(qemuMonitorPtr mon,
> return -1;
> }
>
> - if (qemuMonitorFindBalloonObjectPath(mon, mon->vm, "/") == 1) {
> + if (qemuMonitorFindBalloonObjectPath(mon, mon->vm, "/") == 0) {
A bit of a bikeshed, but the "/" could be moved into the called function
- I say this only because in patch 3 you call qemuMonitorFindObjectPath
with "/".
Could probably also just pass 'mon' and deref 'mon->vm' in the called
routine.
ACK,
John
> ret = qemuMonitorJSONSetMemoryStatsPeriod(mon, mon->balloonpath,
> period);
> }
>
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