--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/pam/src/constants.rs	Sun Sep 24 00:22:29 2017 -0600
@@ -0,0 +1,97 @@
+use libc::{c_int, c_uint};
+
+// TODO: Import constants from C header file at compile time.
+
+pub type PamFlag = c_uint;
+pub type PamItemType = c_int;
+pub type PamMessageStyle = c_int;
+pub type AlwaysZero = c_int;
+
+// The Linux-PAM flags
+// see /usr/include/security/_pam_types.h
+pub const PAM_SILENT: PamFlag = 0x8000;
+pub const PAM_DISALLOW_NULL_AUTHTOK: PamFlag = 0x0001;
+pub const PAM_ESTABLISH_CRED: PamFlag = 0x0002;
+pub const PAM_DELETE_CRED: PamFlag = 0x0004;
+pub const PAM_REINITIALIZE_CRED: PamFlag = 0x0008;
+pub const PAM_REFRESH_CRED: PamFlag = 0x0010;
+pub const PAM_CHANGE_EXPIRED_AUTHTOK: PamFlag = 0x0020;
+
+// The Linux-PAM item types
+// see /usr/include/security/_pam_types.h
+/// The service name
+pub const PAM_SERVICE: PamItemType = 1;
+/// The user name
+pub const PAM_USER: PamItemType = 2;
+/// The tty name
+pub const PAM_TTY: PamItemType = 3;
+/// The remote host name
+pub const PAM_RHOST: PamItemType = 4;
+/// The pam_conv structure
+pub const PAM_CONV: PamItemType = 5;
+/// The authentication token (password)
+pub const PAM_AUTHTOK: PamItemType = 6;
+/// The old authentication token
+pub const PAM_OLDAUTHTOK: PamItemType = 7;
+/// The remote user name
+pub const PAM_RUSER: PamItemType = 8;
+/// the prompt for getting a username
+pub const PAM_USER_PROMPT: PamItemType = 9;
+/* Linux-PAM :extensionsPamItemType = */
+/// app supplied function to override failure delays
+pub const PAM_FAIL_DELAY: PamItemType = 10;
+/// X :display name
+pub const PAM_XDISPLAY: PamItemType = 11;
+/// X :server authentication data
+pub const PAM_XAUTHDATA: PamItemType = 12;
+/// The type for pam_get_authtok
+pub const PAM_AUTHTOK_TYPE: PamItemType = 13;
+
+// Message styles
+pub const PAM_PROMPT_ECHO_OFF: PamMessageStyle = 1;
+pub const PAM_PROMPT_ECHO_ON: PamMessageStyle = 2;
+pub const PAM_ERROR_MSG: PamMessageStyle = 3;
+pub const PAM_TEXT_INFO: PamMessageStyle = 4;
+/// yes/no/maybe conditionals
+pub const PAM_RADIO_TYPE: PamMessageStyle = 5;
+pub const PAM_BINARY_PROMPT: PamMessageStyle = 7;
+
+// The Linux-PAM return values
+// see /usr/include/security/_pam_types.h
+#[allow(non_camel_case_types, dead_code)]
+#[derive(Debug, PartialEq)]
+#[repr(C)]
+pub enum PamResultCode {
+    PAM_SUCCESS = 0,
+    PAM_OPEN_ERR = 1,
+    PAM_SYMBOL_ERR = 2,
+    PAM_SERVICE_ERR = 3,
+    PAM_SYSTEM_ERR = 4,
+    PAM_BUF_ERR = 5,
+    PAM_PERM_DENIED = 6,
+    PAM_AUTH_ERR = 7,
+    PAM_CRED_INSUFFICIENT = 8,
+    PAM_AUTHINFO_UNAVAIL = 9,
+    PAM_USER_UNKNOWN = 10,
+    PAM_MAXTRIES = 11,
+    PAM_NEW_AUTHTOK_REQD = 12,
+    PAM_ACCT_EXPIRED = 13,
+    PAM_SESSION_ERR = 14,
+    PAM_CRED_UNAVAIL = 15,
+    PAM_CRED_EXPIRED = 16,
+    PAM_CRED_ERR = 17,
+    PAM_NO_MODULE_DATA = 18,
+    PAM_CONV_ERR = 19,
+    PAM_AUTHTOK_ERR = 20,
+    PAM_AUTHTOK_RECOVERY_ERR = 21,
+    PAM_AUTHTOK_LOCK_BUSY = 22,
+    PAM_AUTHTOK_DISABLE_AGING = 23,
+    PAM_TRY_AGAIN = 24,
+    PAM_IGNORE = 25,
+    PAM_ABORT = 26,
+    PAM_AUTHTOK_EXPIRED = 27,
+    PAM_MODULE_UNKNOWN = 28,
+    PAM_BAD_ITEM = 29,
+    PAM_CONV_AGAIN = 30,
+    PAM_INCOMPLETE = 31,
+}