[libvirt] [PATCH v2 5/5] storage: fs: Only force directory permissions if required

[Cole Robinson]

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.
---
v2:
    Fix style issue pointed out by pkrempa
    Skip chmod if mode == -1 for the fork/nfs case as well

 src/storage/storage_backend_fs.c | 16 +++++++++++-----
 src/util/virfile.c               |  4 ++--
 2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/src/storage/storage_backend_fs.c b/src/storage/storage_backend_fs.c
index ed56935..3f42a5b 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);
@@ -797,18 +799,22 @@ 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_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) {
         goto error;
     }
 
diff --git a/src/util/virfile.c b/src/util/virfile.c
index 63eafdf..5ff4668 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 (chmod(path, mode) < 0) {
+    if (mode != (mode_t) -1 && chmod(path, mode) < 0) {
         ret = -errno;
         virReportSystemError(errno,
                              _("cannot set mode of '%s' to %04o"),
@@ -2424,7 +2424,7 @@ virDirCreate(const char *path,
                              path, (unsigned int) gid);
         goto childerror;
     }
-    if (chmod(path, mode) < 0) {
+    if (mode != (mode_t) -1 && chmod(path, mode) < 0) {
         virReportSystemError(errno,
                              _("cannot set mode of '%s' to %04o"),
                              path, mode);
-- 
2.4.0