[libvirt] [PATCH 6/6] storage: fs: Only force directory permissions if required

[Peter Krempa]

On Mon, Apr 27, 2015 at 16:48:44 -0400, Cole Robinson wrote:
> Only set directory permissions at pool build time, if:
> 
> - User explicitly requested a mode via the XML
> - The directory needs to be created
> - We need to do the crazy NFS root-squash workaround
> 
> This allows qemu:///session to call build on an existing directory
> like /tmp.
> ---
>  src/storage/storage_backend_fs.c | 16 +++++++++++-----
>  src/util/virfile.c               |  2 +-
>  2 files changed, 12 insertions(+), 6 deletions(-)
> 
> diff --git a/src/storage/storage_backend_fs.c b/src/storage/storage_backend_fs.c
> index 344ee4c..e11c240 100644
> --- a/src/storage/storage_backend_fs.c
> +++ b/src/storage/storage_backend_fs.c
> @@ -769,6 +769,8 @@ virStorageBackendFileSystemBuild(virConnectPtr conn ATTRIBUTE_UNUSED,
>      int err, ret = -1;
>      char *parent = NULL;
>      char *p = NULL;
> +    mode_t mode;
> +    bool needs_create_as_uid;
>  
>      virCheckFlags(VIR_STORAGE_POOL_BUILD_OVERWRITE |
>                    VIR_STORAGE_POOL_BUILD_NO_OVERWRITE, ret);
> @@ -802,19 +804,23 @@ virStorageBackendFileSystemBuild(virConnectPtr conn ATTRIBUTE_UNUSED,
>          }
>      }
>  
> +    needs_create_as_uid = (pool->def->type == VIR_STORAGE_POOL_NETFS);
> +    mode = pool->def->target.perms.mode;
> +    if (mode == (mode_t) -1 &&
> +        (needs_create_as_uid || !virFileExists(pool->def->target.path)))
> +        mode = VIR_STORAGE_DEFAULT_POOL_PERM_MODE;
> +
>      /* Now create the final dir in the path with the uid/gid/mode
>       * requested in the config. If the dir already exists, just set
>       * the perms. */
>      if ((err = virDirCreate(pool->def->target.path,
> -                            (pool->def->target.perms.mode == (mode_t) -1 ?
> -                             VIR_STORAGE_DEFAULT_POOL_PERM_MODE :
> -                             pool->def->target.perms.mode),
> +                            mode,
>                              pool->def->target.perms.uid,
>                              pool->def->target.perms.gid,
>                              VIR_DIR_CREATE_FORCE_PERMS |
>                              VIR_DIR_CREATE_ALLOW_EXIST |
> -                            (pool->def->type == VIR_STORAGE_POOL_NETFS
> -                            ? VIR_DIR_CREATE_AS_UID : 0))) < 0) {
> +                            (needs_create_as_uid ? VIR_DIR_CREATE_AS_UID : 0)
> +                            )) < 0) {

Closing parentheses on a separate line are ugly. I'd rather see
violating the 80 cols rule rather than damaging readability of the code.

>          goto error;
>      }
>  
> diff --git a/src/util/virfile.c b/src/util/virfile.c
> index 676e7b4..7e49f39 100644
> --- a/src/util/virfile.c
> +++ b/src/util/virfile.c
> @@ -2311,7 +2311,7 @@ virDirCreateNoFork(const char *path,
>                               path, (unsigned int) uid, (unsigned int) gid);
>          goto error;
>      }
> -    if ((flags & VIR_DIR_CREATE_FORCE_PERMS)
> +    if (((flags & VIR_DIR_CREATE_FORCE_PERMS) && mode != (mode_t) -1)

This is a usage error of the function. Using mode == -1 and requesting
it to be set doesn't make much sense.

>          && (chmod(path, mode) < 0)) {
>          ret = -errno;
>          virReportSystemError(errno,

ACK.

Peter
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