--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/constants.rs	Thu Mar 05 16:25:10 2015 -0800
@@ -0,0 +1,79 @@
+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 PamResultCode   = 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
+pub const PAM_SERVICE:      PamItemType =  1;   /* The service name */
+pub const PAM_USER:         PamItemType =  2;   /* The user name */
+pub const PAM_TTY:          PamItemType =  3;   /* The tty name */
+pub const PAM_RHOST:        PamItemType =  4;   /* The remote host name */
+pub const PAM_CONV:         PamItemType =  5;   /* The pam_conv structure */
+pub const PAM_AUTHTOK:      PamItemType =  6;   /* The authentication token (password) */
+pub const PAM_OLDAUTHTOK:   PamItemType =  7;   /* The old authentication token */
+pub const PAM_RUSER:        PamItemType =  8;   /* The remote user name */
+pub const PAM_USER_PROMPT:  PamItemType =  9;   /* the prompt for getting a username */
+/* Linux-PAM :extensionsPamItemType = */
+pub const PAM_FAIL_DELAY:   PamItemType = 10;   /* app supplied function to override failure delays */
+pub const PAM_XDISPLAY:     PamItemType = 11;   /* X :display name */
+pub const PAM_XAUTHDATA:    PamItemType = 12;   /* X :server authentication data */
+pub const PAM_AUTHTOK_TYPE: PamItemType = 13;   /* The type for pam_get_authtok */
+
+// 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;
+pub const PAM_RADIO_TYPE:      PamMessageStyle = 5;        /* yes/no/maybe conditionals */
+pub const PAM_BINARY_PROMPT:   PamMessageStyle = 7;
+
+// The Linux-PAM return values
+// see /usr/include/security/_pam_types.h
+pub const PAM_SUCCESS:               PamResultCode =  0;
+pub const PAM_OPEN_ERR:              PamResultCode =  1;
+pub const PAM_SYMBOL_ERR:            PamResultCode =  2;
+pub const PAM_SERVICE_ERR:           PamResultCode =  3;
+pub const PAM_SYSTEM_ERR:            PamResultCode =  4;
+pub const PAM_BUF_ERR:               PamResultCode =  5;
+pub const PAM_PERM_DENIED:           PamResultCode =  6;
+pub const PAM_AUTH_ERR:              PamResultCode =  7;
+pub const PAM_CRED_INSUFFICIENT:     PamResultCode =  8;
+pub const PAM_AUTHINFO_UNAVAIL:      PamResultCode =  9;
+pub const PAM_USER_UNKNOWN:          PamResultCode = 10;
+pub const PAM_MAXTRIES:              PamResultCode = 11;
+pub const PAM_NEW_AUTHTOK_REQD:      PamResultCode = 12;
+pub const PAM_ACCT_EXPIRED:          PamResultCode = 13;
+pub const PAM_SESSION_ERR:           PamResultCode = 14;
+pub const PAM_CRED_UNAVAIL:          PamResultCode = 15;
+pub const PAM_CRED_EXPIRED:          PamResultCode = 16;
+pub const PAM_CRED_ERR:              PamResultCode = 17;
+pub const PAM_NO_MODULE_DATA:        PamResultCode = 18;
+pub const PAM_CONV_ERR:              PamResultCode = 19;
+pub const PAM_AUTHTOK_ERR:           PamResultCode = 20;
+pub const PAM_AUTHTOK_RECOVERY_ERR:  PamResultCode = 21;
+pub const PAM_AUTHTOK_LOCK_BUSY:     PamResultCode = 22;
+pub const PAM_AUTHTOK_DISABLE_AGING: PamResultCode = 23;
+pub const PAM_TRY_AGAIN:             PamResultCode = 24;
+pub const PAM_IGNORE:                PamResultCode = 25;
+pub const PAM_ABORT:                 PamResultCode = 26;
+pub const PAM_AUTHTOK_EXPIRED:       PamResultCode = 27;
+pub const PAM_MODULE_UNKNOWN:        PamResultCode = 28;
+pub const PAM_BAD_ITEM:              PamResultCode = 29;
+pub const PAM_CONV_AGAIN:            PamResultCode = 30;
+pub const PAM_INCOMPLETE:            PamResultCode = 31;