/*
 * The contents of this header are copied directly from the X/SSO PAM spec,
 * with comments and unpopular functions removed.
 *
 * https://pubs.opengroup.org/onlinepubs/8329799/apdxa.htm
 */
#define PAM_SUCCESS 0
#define PAM_OPEN_ERR 1
#define PAM_SYMBOL_ERR 2
#define PAM_SERVICE_ERR 3
#define PAM_SYSTEM_ERR 4
#define PAM_BUF_ERR 5
#define PAM_CONV_ERR 6
#define PAM_PERM_DENIED 7
#define PAM_MAXTRIES 8
#define PAM_AUTH_ERR 9
#define PAM_NEW_AUTHTOK_REQD 10
#define PAM_CRED_INSUFFICIENT 11
#define PAM_AUTHINFO_UNAVAIL 12
#define PAM_USER_UNKNOWN 13
#define PAM_CRED_UNAVAIL 14
#define PAM_CRED_EXPIRED 15
#define PAM_CRED_ERR 16
#define PAM_ACCT_EXPIRED 17
#define PAM_AUTHTOK_EXPIRED 18
#define PAM_SESSION_ERR 19
#define PAM_AUTHTOK_ERR 20
#define PAM_AUTHTOK_RECOVERY_ERR 21
#define PAM_AUTHTOK_LOCK_BUSY 22
#define PAM_AUTHTOK_DISABLE_AGING 23
#define PAM_NO_MODULE_DATA 24
#define PAM_IGNORE 25
#define PAM_ABORT 26
#define PAM_TRY_AGAIN 27
/* PAM_MODULE_UNKNOWN and PAM_DOMAIN_UNKNOWN are not universal. */

struct pam_message {
  int msg_style;
  char *msg;
};

#define PAM_PROMPT_ECHO_OFF 1
#define PAM_PROMPT_ECHO_ON 2
#define PAM_ERROR_MSG 3
#define PAM_TEXT_INFO 4

#define PAM_MAX_NUM_MSG 32
#define PAM_MAX_MSG_SIZE 512
#define PAM_MAX_RESP_SIZE 512

struct pam_response {
  char *resp;
  int resp_retcode;
};

struct pam_conv {
  int (*conv)(int, struct pam_message **, struct pam_response **, void *);
  void *appdata_ptr;
};

typedef struct pam_handle pam_handle_t;

extern int pam_start(const char *service_name,
                     const char *user,
                     const struct pam_conv *pam_conv,
                     pam_handle_t **pamh);

extern int pam_end(pam_handle_t *pamh, int status);

extern int pam_set_item(pam_handle_t *pamh, int item_type, const void *item);

extern int pam_get_item(const pam_handle_t *pamh, int item_type, void **item);

#define PAM_SERVICE 1
#define PAM_USER 2
#define PAM_TTY 3
#define PAM_RHOST 4
#define PAM_CONV 5
#define PAM_AUTHTOK 6
#define PAM_OLDAUTHTOK 7
#define PAM_RUSER 8
#define PAM_USER_PROMPT 9

extern int pam_get_user(pam_handle_t *pamh, char **user, const char *prompt);

extern int pam_set_data(pam_handle_t *pamh,
                        const char *module_data_name,
                        const void *data,
                        void (*cleanup)(pam_handle_t *pamh,
                                        void *data,
                                        int pam_end_status));

extern int pam_get_data(const pam_handle_t *pamh,
                        const char *module_data_name,
                        void **data);

extern char *pam_strerror(pam_handle_t *pamh, int errnum);

#define PAM_SILENT 0x80000000

extern int pam_authenticate(pam_handle_t *pamh, int flags);

#define PAM_DISALLOW_NULL_AUTHTOK 0x1

/* Nobody implements pam_authenticate_secondary. */

extern int pam_acct_mgmt(pam_handle_t *pamh, int flags);

extern int pam_open_session(pam_handle_t *pamh, int flags);

extern int pam_close_session(pam_handle_t *pamh, int flags);

extern int pam_setcred(pam_handle_t *pamh, int flags);

#define PAM_ESTABLISH_CRED 0x1
#define PAM_DELETE_CRED 0x2
#define PAM_REINITIALIZE_CRED 0x4

#define PAM_REFRESH_CRED 0x8

extern int pam_chauthtok(pam_handle_t *pamh, int flags);

#define PAM_CHANGE_EXPIRED_AUTHTOK 0x4

extern char *pam_getenv(pam_handle_t *pamh, const char *name);

extern char **pam_getenvlist(pam_handle_t *pamh);

extern int pam_putenv(pam_handle_t *pamh, const char *namevalue);

/* Nobody implements the _mapped functions. */

extern int pam_get_user(pam_handle_t *pamh, char **user, const char *prompt);

/* The following constants come from the `pam_module.h` part of the page. */
#define PAM_PRELIM_CHECK 0x1
#define PAM_UPDATE_AUTHTOK 0x2

/* The _sm functions are not exported symbols, but prototypes for modules. */