Reporting broken symlinks to clients

[Christof Schmitt]

I got asked if it would make sense to report broken symlinks to
Windows clients. With the current code, the stat() call in
smbd_dirptr_lanman2_mode_fn fails on the broken symlink and it is not
reported in the directory listing to the client. This could be changed
without too much effort, like this hack:

--- a/source3/smbd/trans2.c
+++ b/source3/smbd/trans2.c
@@ -1553,11 +1553,22 @@ static bool
smbd_dirptr_lanman2_mode_fn(TALLOC_CTX *ctx,
                   SMB_VFS_STAT(state->conn, smb_fname) != 0) {
                /* Needed to show the msdfs symlinks as
                 * directories */
+               int stat_errno = errno;
 
                ms_dfs_link = check_msdfs_link(state->conn,
                                               smb_fname->base_name,
                                               &smb_fname->st);
-               if (!ms_dfs_link) {
+               if (!ms_dfs_link && stat_errno == ENOENT) {
+                       /* Invalid link target, try to get lstat() data to show
+                        * a dummy file */
+                       if (SMB_VFS_LSTAT(state->conn, smb_fname) != 0) {
+                               DEBUG(5,("smbd_dirptr_lanman2_mode_fn: "
+                                        "Couldn't stat and lstat [%s] (%s)\n",
+                                        smb_fname_str_dbg(smb_fname),
+                                        strerror(errno)));
+                               return false;
+                       }
+               } else if (!ms_dfs_link) {
                        DEBUG(5,("smbd_dirptr_lanman2_mode_fn: "
                                 "Couldn't stat [%s] (%s)\n",
                                 smb_fname_str_dbg(smb_fname),

This could be useful in environments where the same directory is
accessible to Windows clients and to Linux/Unix systems. When a
broken symlink is created, the Windows clients would at least be able
to see that there is a file.

Comments?

-- 
Christof Schmitt || IBM || SONAS System Development || Tucson, AZ
christof.schmitt at us.ibm.com  ||  +1-520-799-2469  (T/L: 321-2469)