qacl: Reimplement qset_acl and qcopy_acl (Bug#20666)

Implement get_permissions and set_permissions primitives for getting all
the permissions of a file, storing them, and later setting them. (In the
minimal case, the permissions consist only of a file mode.) Reimplement
qset_acl and qcopy_acl based on these new primitives: this avoids code
duplication and makes error handling more consistent.

The Solaris and Cygwin code still uses duplicate code paths for setting
a file mode while making sure that no acls exist and setting an explicit
acl; this is no worse than before, but could be cleaned up.  The AIX
code still doesn't read ACLs, it only makes sure that acls don't get in
the way when setting a file mode.

* lib/acl-internal.h (struct permission_context): New data structure.
(get_permissions, set_permissions, free_permission_context): Declare.
* lib/acl-internal.c (free_permission_context): New helper function.
* lib/get-permissions.c (get_permissions): New helper function split off
from qcopy_acl.
* lib/set-permissions.c: (set_acls_from_mode): On Solaris, Cygwin, and
AIX, set a file's permissions based only on a file mode.
(acl_from_mode, context_acl_from_mode, context_aclv_from_mode): All
other platforms construct a temporary acl from the file mode and set
that acl in the same way as setting an acl read from the source file.
This should help avoid code duplication and inconsistent / buggy
behavior.
(set_acls): New helper function Split off from qcopy_acl.
(chmod_or_fchmod): Moved here from qset-acl.c.
(set_permissions): New helper function.
* lib/qcopy-acl.c (qcopy_acl): Rewrite using get_permissions and
set_permissions.
* lib/qset-acl.c (qset_acl): Rewrite using set_permissions.
* modules/qacl: Add get-permissions.c and set-permissions.c.

1 files changed, 31 insertions, 0 deletions

diff --git a/lib/acl-internal.c b/lib/acl-internal.c
index d9bd4461ea..1a2f8c44bf 100644
--- a/lib/acl-internal.c
+++ b/lib/acl-internal.c
@@ -467,3 +467,34 @@ acl_nontrivial (int count, struct acl *entries)
 }
 
 #endif
+
+void
+free_permission_context (struct permission_context *ctx)
+{
+#ifdef USE_ACL
+# if HAVE_ACL_GET_FILE /* Linux, FreeBSD, Mac OS X, IRIX, Tru64 */
+  if (ctx->acl)
+    acl_free (ctx->acl);
+#  if !HAVE_ACL_TYPE_EXTENDED
+  if (ctx->default_acl)
+    acl_free (ctx->default_acl);
+#  endif
+
+# elif defined GETACL /* Solaris, Cygwin */
+  free (ctx->entries);
+#  ifdef ACE_GETACL
+  free (ctx->ace_entries);
+#  endif
+
+# elif HAVE_GETACL /* HP-UX */
+
+#  if HAVE_ACLV_H
+#  endif
+
+# elif HAVE_STATACL /* older AIX */
+
+# elif HAVE_ACLSORT /* NonStop Kernel */
+
+# endif
+#endif
+}