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

[Cole Robinson]

First, thanks for following up on the fedora bugs so quickly!

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.
> 

I see you sent a qemu patch for a similar change. What's the benefit of
libvirt setting cancel_path if qemu can (and already attempts to) figure it out?

- Cole

> Signed-off-by: Stefan Berger <stefanb at linux.vnet.ibm.com>
> ---
>  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, "/sys/class/misc/%s/device/cancel",
> -                            dev) < 0)
> +            for (i = 0; i < ARRAY_CARDINALITY(prefix); i++) {
> +                if (virAsprintf(&path, "/sys/class/%s%s/device/cancel",
> +                                prefix[i], dev) < 0)
> +                     goto cleanup;
> +
> +                fd = open(path, O_WRONLY);
> +                if (fd >= 0) {
> +                    VIR_FORCE_CLOSE(fd);
> +                    break;
> +                }
> +                VIR_FREE(path);
> +            }
> +            /* /dev/null does not allow to cancel cmds but it can be used */
> +            if (!path && virAsprintf(&path, "/dev/null") < 0)
>                  goto cleanup;
>          } else {
>              virReportError(VIR_ERR_INTERNAL_ERROR,
> diff --git a/tests/qemuxml2argvmock.c b/tests/qemuxml2argvmock.c
> index d24725e..e58b8ce 100644
> --- a/tests/qemuxml2argvmock.c
> +++ b/tests/qemuxml2argvmock.c
> @@ -24,9 +24,13 @@
>  #include "virnuma.h"
>  #include "virmock.h"
>  #include "virutil.h"
> +#include "virstring.h"
> +#include "virtpm.h"
>  #include <time.h>
>  #include <unistd.h>
>  
> +#define VIR_FROM_THIS VIR_FROM_NONE
> +
>  long virGetSystemPageSize(void)
>  {
>      return 4096;
> @@ -59,3 +63,14 @@ virNumaNodeIsAvailable(int node)
>      return node >= 0 && node <= virNumaGetMaxNode();
>  }
>  #endif /* WITH_NUMACTL && HAVE_NUMA_BITMASK_ISBITSET */
> +
> +char *
> +virTPMCreateCancelPath(const char *devpath)
> +{
> +    char *path;
> +    (void)devpath;
> +
> +    ignore_value(VIR_STRDUP(path, "/sys/class/misc/tpm0/device/cancel"));
> +
> +    return path;
> +}
>