Re: [libvirt] [PATCH 2/6] Clarify the semantic of virDomainGetSchedulerParameters arguments

params and nparams are essential and cannot be NULL. Check this in libvirt.c and remove redundant checks from the drivers (e.g. xend). Instead of enforcing that nparams must point to exact same value as returned by virDomainGetSchedulerType relax this to a lower bound check. This is what some drivers (e.g. xen hypervisor and esx) already did. Other drivers (e.g. xend) didn't check nparams at all and assumed that there is enough space in params. Unify the behavior in all drivers to a lower bound check and update nparams to the number of valid values in params on success.

- * Get the scheduler parameters, the @params array will be filled with the - * values. + * Get all scheduler parameters, the @params array will be filled with the + * values and @nparams will be updated to the number of valid elements in + * @params. * * Returns -1 in case of error, 0 in case of success. */ @@ -5041,6 +5042,12 @@ virDomainGetSchedulerParameters(virDomainPtr domain, virDispatchError(NULL); return -1; } + + if (params == NULL || nparams == NULL || *nparams < 0) {

+ virLibDomainError(VIR_ERR_INVALID_ARG, __FUNCTION__); + goto error; + } + conn = domain->conn; if (conn->driver->domainGetSchedulerParameters) { diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c index 6b2d806..b85c743 100644 --- a/src/libxl/libxl_driver.c +++ b/src/libxl/libxl_driver.c @@ -2466,7 +2466,7 @@ libxlDomainGetSchedulerParameters(virDomainPtr dom, virSchedParameterPtr params, goto cleanup; } - if (*nparams != XEN_SCHED_CREDIT_NPARAM) { + if (*nparams < XEN_SCHED_CREDIT_NPARAM) { libxlError(VIR_ERR_INVALID_ARG, "%s", _("Invalid parameter count")); goto cleanup; } @@ -2494,6 +2494,7 @@ libxlDomainGetSchedulerParameters(virDomainPtr dom, virSchedParameterPtr params, goto cleanup; } + *nparams = XEN_SCHED_CREDIT_NPARAM; ret = 0; cleanup: diff --git a/src/lxc/lxc_driver.c b/src/lxc/lxc_driver.c index 2bb592d..a65299b 100644 --- a/src/lxc/lxc_driver.c +++ b/src/lxc/lxc_driver.c @@ -2234,7 +2234,7 @@ static int lxcGetSchedulerParameters(virDomainPtr domain, if (driver->cgroup == NULL) return -1; - if ((*nparams) != 1) { + if (*nparams < 1) {