From 1cd55f9dc7debdad0d54f4fad8617527433b4c4b Mon Sep 17 00:00:00 2001 From: Janosch Frank Date: Mon, 11 Jan 2016 16:18:01 +0100 Subject: scripts/kvm/kvm_stat: Fix rlimit for unprivileged users Setting the hard limit as a unprivileged user either returns an error when it is higher than the current one or irreversibly sets it lower. Therefore we leave the hardlimit untouched as long as we don't need to raise it as this needs CAP_SYS_RESOURCE. This gives admins the possibility to run the script as an unprivileged user to increase security. Signed-off-by: Janosch Frank Message-Id: <1452525484-32309-32-git-send-email-frankja@linux.vnet.ibm.com> Signed-off-by: Paolo Bonzini --- scripts/kvm/kvm_stat | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/scripts/kvm/kvm_stat b/scripts/kvm/kvm_stat index 611f82ad2a..2a1842e33e 100755 --- a/scripts/kvm/kvm_stat +++ b/scripts/kvm/kvm_stat @@ -434,11 +434,19 @@ class TracepointProvider(object): # The constant is needed as a buffer for python libs, std # streams and other files that the script opens. - rlimit = len(cpus) * len(self._fields) + 50 + newlim = len(cpus) * len(self._fields) + 50 try: - resource.setrlimit(resource.RLIMIT_NOFILE, (rlimit, rlimit)) + softlim_, hardlim = resource.getrlimit(resource.RLIMIT_NOFILE) + + if hardlim < newlim: + # Now we need CAP_SYS_RESOURCE, to increase the hard limit. + resource.setrlimit(resource.RLIMIT_NOFILE, (newlim, newlim)) + else: + # Raising the soft limit is sufficient. + resource.setrlimit(resource.RLIMIT_NOFILE, (newlim, hardlim)) + except ValueError: - sys.exit("NOFILE rlimit could not be raised to {0}".format(rlimit)) + sys.exit("NOFILE rlimit could not be raised to {0}".format(newlim)) for cpu in cpus: group = Group() -- cgit v1.2.3