Re: [libvirt] [PATCH v2] tpm: adapt sysfs cancel path for new TPM driver

From: Cole Robinson <crobinso(a)redhat.com&gt; To: Stefan Berger/Watson/IBM@IBMUS, libvir-list(a)redhat.com, berrange(a)redhat.com Cc: Stefan Berger <stefanb(a)linux.vnet.ibm.com&gt; Date: 11/17/2015 04:38 PM Subject: Re: [PATCH v2] tpm: adapt sysfs cancel path for new TPM driver On 11/17/2015 10:46 AM, Stefan Berger wrote: > Adapt the sysfs TPM command cancel path for the TPM driver that > does not use a miscdevice anymore since Linux 4.0. Support old > and new paths and check their availability. > > Add a mockup for the test cases to avoid the testing for > availability of the cancel path. > > Signed-off-by: Stefan Berger <stefanb(a)linux.vnet.ibm.com&gt; > --- > src/util/virtpm.c | 22 ++++++++++++++++++++-- > tests/qemuxml2argvmock.c | 15 +++++++++++++++ > 2 files changed, 35 insertions(+), 2 deletions(-) > > diff --git a/src/util/virtpm.c b/src/util/virtpm.c > index 88f8361..3872a31 100644 > --- a/src/util/virtpm.c > +++ b/src/util/virtpm.c > @@ -23,9 +23,12 @@ > #include <config.h> > > #include <sys/stat.h> > +#include <fcntl.h> > > #include "virstring.h" > #include "virerror.h" > +#include "viralloc.h" > +#include "virfile.h" > #include "virtpm.h" > > #define VIR_FROM_THIS VIR_FROM_NONE > @@ -41,13 +44,28 @@ virTPMCreateCancelPath(const char *devpath) > { > char *path = NULL; > const char *dev; > + const char *prefix[] = {"misc/", "tpm/"}; > + size_t i; > + int fd; > > if (devpath) { > dev = strrchr(devpath, '/'); > if (dev) { > dev++; > - if (virAsprintf(&path,

> - dev) < 0) > + for (i = 0; i < ARRAY_CARDINALITY(prefix); i++) { > + if (virAsprintf(&path,

> + prefix[i], dev) < 0) > + goto cleanup; > + > + fd = open(path, O_WRONLY); > + if (fd >= 0) { > + VIR_FORCE_CLOSE(fd); > + break; > + } > + VIR_FREE(path); > + } You can use virFileExists(path) to simplify this

> + /* /dev/null does not allow to cancel cmds but it canbe

> + if (!path && virAsprintf(&path, "/dev/null") < 0) > goto cleanup; > } else { Hmm, does this mean we might selinux relabel /dev/null? Maybe just fall

to no cancel-path if we want this to be non-fatal