On 10/28/2013 11:40 PM, Daniel P. Berrange wrote:
> From: "Daniel P. Berrange" <berrange@xxxxxxxxxx>
>
> Add a function for efficiently checking if a path is a filesystem
> mount point.
>
> NB will not work for bind mounts, only true filesystem mounts.
>
> Signed-off-by: Daniel P. Berrange <berrange@xxxxxxxxxx>
> ---
> src/libvirt_private.syms | 1 +
> src/util/virfile.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++
> src/util/virfile.h | 2 ++
> 3 files changed, 53 insertions(+)
>
> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
> index f1f817c..ea68490 100644
> --- a/src/libvirt_private.syms
> +++ b/src/libvirt_private.syms
> @@ -1188,6 +1188,7 @@ virFileIsAbsPath;
> virFileIsDir;
> virFileIsExecutable;
> virFileIsLink;
> +virFileIsMountPoint;
> virFileLinkPointsTo;
> virFileLock;
> virFileLoopDeviceAssociate;
> diff --git a/src/util/virfile.c b/src/util/virfile.c
> index 3a9980c..9fde99c 100644
> --- a/src/util/virfile.c
> +++ b/src/util/virfile.c
> @@ -1518,6 +1518,56 @@ virFileIsExecutable(const char *file)
> return false;
> }
>
> +
> +/*
> + * Check that a file refers to a mount point. Trick is that for
> + * a mount point, the st_dev field will differ from the parent
> + * directory.
> + *
> + * Note that this will not detect bind mounts of dirs/files,
> + * only true filesystem mounts.
> + */
> +int virFileIsMountPoint(const char *file)
> +{
> + char *parent = NULL;
> + int ret = -1;
> + struct stat sb1, sb2;
> +
> + if (!(parent = mdir_name(file))) {
> + virReportOOMError();
> + goto cleanup;
> + }
> +
> + VIR_DEBUG("Comparing '%s' to '%s'", file, parent);
> +
> + if (stat(file, &sb1) < 0) {
> + if (errno == ENOENT)
> + ret = 0;
> + else
> + virReportSystemError(errno,
> + _("Cannot stat '%s'"),
> + file);
> + goto cleanup;
> + }
> +
> + if (stat(parent, &sb2) < 0) {
> + virReportSystemError(errno,
> + _("Cannot stat '%s'"),
> + parent);
> + goto cleanup;
> + }
> +
> + if (!S_ISDIR(sb1.st_mode))
VIR_FREE(parent)
Acked-by: Gao feng <gaofeng@xxxxxxxxxxxxxx>
> + return false;
> +
> + ret = sb1.st_dev != sb2.st_dev;
> + VIR_DEBUG("Is mount %d", ret);
> +
> + cleanup:
> + VIR_FREE(parent);
> + return ret;
> +}
> +
> #ifndef WIN32
> /* Check that a file is accessible under certain
> * user & gid.
> diff --git a/src/util/virfile.h b/src/util/virfile.h
> index 72d35ce..ff84719 100644
> --- a/src/util/virfile.h
> +++ b/src/util/virfile.h
> @@ -156,6 +156,8 @@ bool virFileIsDir (const char *file) ATTRIBUTE_NONNULL(1);
> bool virFileExists(const char *file) ATTRIBUTE_NONNULL(1);
> bool virFileIsExecutable(const char *file) ATTRIBUTE_NONNULL(1);
>
> +int virFileIsMountPoint(const char *file) ATTRIBUTE_NONNULL(1);
> +
> char *virFileSanitizePath(const char *path);
>
> enum {
>
--
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