auto import from //depot/cupcake/@135843
diff --git a/libc/unistd/initgroups.c b/libc/unistd/initgroups.c
new file mode 100644
index 0000000..dea6d96
--- /dev/null
+++ b/libc/unistd/initgroups.c
@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+#include <grp.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+#define INIT_GROUPS 2
+
+int
+initgroups (const char *user, gid_t group)
+{
+ gid_t groups0[ INIT_GROUPS ];
+ gid_t* groups = groups0;
+ int ret = -1;
+ int numgroups = INIT_GROUPS;
+
+ if (getgrouplist(user, group, groups, &numgroups) < 0) {
+ groups = malloc(numgroups*sizeof(groups[0]));
+ if (groups == NULL)
+ return -1;
+ if (getgrouplist(user,group,groups,&numgroups) < 0) {
+ goto EXIT;
+ }
+ }
+
+ ret = setgroups(numgroups, groups);
+
+EXIT:
+ if (groups != groups0)
+ free(groups);
+
+ return ret;
+}