symlink: readdir and directory symlinks

windows differentiates between directory and file symlinks because a file can have both FILE_ATTRIBUTE_DIRECTORY and FILE_ATTRIBUTE_REPARSE_POINT flags.  nfs can only be one of NF4REG/DIR/LNK, so we have to do a readlink and look up the target file for symlinks to know whether or not to set the directory attribute flag.  this is done recursively when we encounter links to links

Signed-off-by: Casey Bodley <cbodley@citi.umich.edu>

daemon/readdir.c

@@ -170,6 +170,10 @@ static void readdir_copy_dir_info(
             entry->attr_info.size;
     info->fdi.FileAttributes = nfs_file_info_to_attributes(
         &entry->attr_info);
+
+    /* use cansettime to flag the symlink target as a directory */
+    if (entry->attr_info.cansettime)
+        info->fdi.FileAttributes |= FILE_ATTRIBUTE_DIRECTORY;
 }
 
 static void readdir_copy_shortname(
@@ -214,6 +218,26 @@ static void readdir_copy_filename(
     memcpy(name_out, name, name_size);
 }
 
+static int format_abs_path(
+    IN const nfs41_abs_path *path,
+    IN const nfs41_component *name,
+    OUT nfs41_abs_path *path_out)
+{
+    /* format an absolute path 'parent\name' */
+    int status = NO_ERROR;
+
+    InitializeSRWLock(&path_out->lock);
+    abs_path_copy(path_out, path);
+    if (FAILED(StringCchPrintfA(path_out->path + path_out->len,
+        NFS41_MAX_PATH_LEN - path_out->len, "\\%s", name->name))) {
+        status = ERROR_BUFFER_OVERFLOW;
+        goto out;
+    }
+    path_out->len += name->len + 1;
+out:
+    return status;
+}
+
 static int lookup_entry(
     IN nfs41_root *root,
     IN nfs41_session *session,
@@ -221,29 +245,60 @@ static int lookup_entry(
     OUT nfs41_readdir_entry *entry)
 {
     nfs41_abs_path path;
-    nfs41_path_fh file;
+    nfs41_component name;
     int status;
 
-    /* format an absolute path 'parent\name' */
+    name.name = entry->name;
-    InitializeSRWLock(&path.lock);
+    name.len = (unsigned short)entry->name_len;
-    abs_path_copy(&path, parent->path);
-    if (path.len + entry->name_len >= NFS41_MAX_PATH_LEN) {
-        status = ERROR_BUFFER_OVERFLOW;
-        goto out;
-    }
-    StringCchPrintfA(path.path + path.len,
-        NFS41_MAX_PATH_LEN - path.len, "\\%s", entry->name);
-    path.len += (unsigned short)entry->name_len;
 
-    path_fh_init(&file, &path);
+    status = format_abs_path(parent->path, &name, &path);
+    if (status) goto out;
 
     status = nfs41_lookup(root, session, &path,
         NULL, NULL, &entry->attr_info, NULL);
-    if (status) {
+    if (status) goto out;
-        dprintf(1, "nfs41_lookup failed with %s\n", nfs_error_string(status));
+out:
-        status = nfs_to_windows_error(status, ERROR_BAD_NET_RESP);
+    return status;
-        goto out;
 }
+
+static int lookup_symlink(
+    IN nfs41_root *root,
+    IN nfs41_session *session,
+    IN nfs41_path_fh *parent,
+    IN const nfs41_component *name,
+    OUT nfs41_file_info *info_out)
+{
+    nfs41_abs_path path;
+    nfs41_path_fh link_parent, file;
+    nfs41_file_info info;
+    int status;
+
+    status = format_abs_path(parent->path, name, &path);
+    if (status) goto out;
+
+    file.path = &path;
+    /* get a filehandle for the symlink */
+    status = nfs41_lookup(root, session, &path, NULL, &file, &info, NULL);
+    if (status) goto out;
+
+    link_parent.path = &path;
+    last_component(path.path, path.path + path.len, &file.name);
+    last_component(path.path, file.name.name, &link_parent.name);
+
+    /* attempt to follow the symlink */
+    status = nfs41_symlink_follow(session, &file, &path);
+    if (status) goto out;
+
+    /* get attributes for the target */
+    status = nfs41_lookup(root, session, &path, &link_parent, NULL, &info, NULL);
+    if (status) goto out;
+
+    if (info.type == NF4LNK) {
+        status = lookup_symlink(root, session, &link_parent, &file.name, &info);
+        if (status) goto out;
+        info_out->cansettime = info.cansettime;
+    } else if (info.type == NF4DIR)
+        info_out->cansettime = 1;
 out:
     return status;
 }
@@ -280,6 +335,12 @@ static int readdir_copy_entry(
          * it's okay if lookup fails, we'll just write garbage attributes */
         lookup_entry(args->root, args->state->session,
             &args->state->file, entry);
+    } else if (entry->attr_info.type == NF4LNK) {
+        const nfs41_component name = { entry->name,
+            (unsigned short)entry->name_len - 1 };
+        /* look up the symlink target to see whether it's a directory */
+        lookup_symlink(args->root, args->state->session,
+            &args->state->file, &name, &entry->attr_info);
     }
 
     switch (args->query_class)