vfs_error_inject: Add new module

This module allow injecting errors in vfs calls. It only implements one
case (return ESTALE from chdir), but the idea is to extend this to more
vfs functions and more errors when needed.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=13189

Signed-off-by: Christof Schmitt <cs@samba.org>
Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>

diff --git a/source3/modules/vfs_error_inject.c b/source3/modules/vfs_error_inject.c
new file mode 100644 (file)
index 0000000..bb5477a
--- /dev/null
+++ b/source3/modules/vfs_error_inject.c
@@ -0,0 +1,100 @@
+/*
+ *  Unix SMB/CIFS implementation.
+ *  Samba VFS module for error injection in VFS calls
+ *  Copyright (C) Christof Schmitt 2017
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "includes.h"
+#include "smbd/smbd.h"
+
+#undef DBGC_CLASS
+#define DBGC_CLASS DBGC_VFS
+
+struct unix_error_map {
+       const char *err_str;
+       int error;
+} unix_error_map_array[] = {
+       {       "ESTALE",       ESTALE  },
+};
+
+static int find_unix_error_from_string(const char *err_str)
+{
+       int i;
+
+       for (i = 0; i < ARRAY_SIZE(unix_error_map_array); i++) {
+               struct unix_error_map *m = &unix_error_map_array[i];
+
+               if (strequal(err_str, m->err_str)) {
+                       return m->error;
+               }
+       }
+
+       return 0;
+}
+
+static int inject_unix_error(const char *vfs_func, vfs_handle_struct *handle)
+{
+       const char *err_str;
+
+       err_str = lp_parm_const_string(SNUM(handle->conn),
+                                      "error_inject", vfs_func, NULL);
+
+       if (err_str != NULL) {
+               int error;
+
+               error = find_unix_error_from_string(err_str);
+               if (error != 0) {
+                       DBG_WARNING("Returning error %s for VFS function %s\n",
+                                   err_str, vfs_func);
+                       return error;
+               }
+
+               if (strequal(err_str, "panic")) {
+                       DBG_ERR("Panic in VFS function %s\n", vfs_func);
+                       smb_panic("error_inject");
+               }
+
+               DBG_ERR("Unknown error inject %s requested "
+                       "for vfs function %s\n", err_str, vfs_func);
+       }
+
+       return 0;
+}
+
+static int vfs_error_inject_chdir(vfs_handle_struct *handle,
+                                 const struct smb_filename *smb_fname)
+{
+       int error;
+
+       error = inject_unix_error("chdir", handle);
+       if (error != 0) {
+               errno = error;
+               return -1;
+       }
+
+       return SMB_VFS_NEXT_CHDIR(handle, smb_fname);
+}
+
+static struct vfs_fn_pointers vfs_error_inject_fns = {
+       .chdir_fn = vfs_error_inject_chdir,
+};
+
+static_decl_vfs;
+NTSTATUS vfs_error_inject_init(TALLOC_CTX *ctx)
+{
+       return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "error_inject",
+                               &vfs_error_inject_fns);
+}

diff --git a/source3/modules/wscript_build b/source3/modules/wscript_build
index 4e4fdb98a1d964171b31dc89a6fec090f858d485..079302cd584c8526a963741314c087b34e7a98e4 100644 (file)
--- a/source3/modules/wscript_build
+++ b/source3/modules/wscript_build
@@ -525,3 +525,10 @@ bld.SAMBA3_MODULE('vfs_fake_dfq',
                  init_function='',
                  internal_module=bld.SAMBA3_IS_STATIC_MODULE('vfs_fake_dfq'),
                  enabled=bld.SAMBA3_IS_ENABLED_MODULE('vfs_fake_dfq'))
+
+bld.SAMBA3_MODULE('vfs_error_inject',
+                 subsystem='vfs',
+                 source='vfs_error_inject.c',
+                 init_function='',
+                 internal_module=bld.SAMBA3_IS_STATIC_MODULE('vfs_error_inject'),
+                 enabled=bld.SAMBA3_IS_ENABLED_MODULE('vfs_error_inject'))

diff --git a/source3/wscript b/source3/wscript
index d45a7d9ec606a2f638f09f3b448253a3ca72c1a0..0f8fe5452daf4fd5676a1695b5307ede562a1113 100644 (file)
--- a/source3/wscript
+++ b/source3/wscript
@@ -1674,6 +1674,7 @@ main() {
 
     if Options.options.enable_selftest or Options.options.developer:
         default_shared_modules.extend(TO_LIST('vfs_fake_acls vfs_nfs4acl_xattr'))
+        default_shared_modules.extend(TO_LIST('vfs_error_inject'))
 
     if conf.CONFIG_SET('AD_DC_BUILD_IS_ENABLED'):
         default_static_modules.extend(TO_LIST('pdb_samba_dsdb auth_samba4 vfs_dfs_samba4'))