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Filename : ui.h
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/*
 * Copyright 2001-2018 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the OpenSSL license (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

#ifndef HEADER_UI_H
# define HEADER_UI_H

# include <openssl/opensslconf.h>

# if OPENSSL_API_COMPAT < 0x10100000L
#  include <openssl/crypto.h>
# endif
# include <openssl/safestack.h>
# include <openssl/pem.h>
# include <openssl/ossl_typ.h>
# include <openssl/uierr.h>

/* For compatibility reasons, the macro OPENSSL_NO_UI is currently retained */
# if OPENSSL_API_COMPAT < 0x10200000L
#  ifdef OPENSSL_NO_UI_CONSOLE
#   define OPENSSL_NO_UI
#  endif
# endif

# ifdef  __cplusplus
extern "C" {
# endif

/*
 * All the following functions return -1 or NULL on error and in some cases
 * (UI_process()) -2 if interrupted or in some other way cancelled. When
 * everything is fine, they return 0, a positive value or a non-NULL pointer,
 * all depending on their purpose.
 */

/* Creators and destructor.   */
UI *UI_new(void);
UI *UI_new_method(const UI_METHOD *method);
void UI_free(UI *ui);

/*-
   The following functions are used to add strings to be printed and prompt
   strings to prompt for data.  The names are UI_{add,dup}_<function>_string
   and UI_{add,dup}_input_boolean.

   UI_{add,dup}_<function>_string have the following meanings:
        add     add a text or prompt string.  The pointers given to these
                functions are used verbatim, no copying is done.
        dup     make a copy of the text or prompt string, then add the copy
                to the collection of strings in the user interface.
        <function>
                The function is a name for the functionality that the given
                string shall be used for.  It can be one of:
                        input   use the string as data prompt.
                        verify  use the string as verification prompt.  This
                                is used to verify a previous input.
                        info    use the string for informational output.
                        error   use the string for error output.
   Honestly, there's currently no difference between info and error for the
   moment.

   UI_{add,dup}_input_boolean have the same semantics for "add" and "dup",
   and are typically used when one wants to prompt for a yes/no response.

   All of the functions in this group take a UI and a prompt string.
   The string input and verify addition functions also take a flag argument,
   a buffer for the result to end up with, a minimum input size and a maximum
   input size (the result buffer MUST be large enough to be able to contain
   the maximum number of characters).  Additionally, the verify addition
   functions takes another buffer to compare the result against.
   The boolean input functions take an action description string (which should
   be safe to ignore if the expected user action is obvious, for example with
   a dialog box with an OK button and a Cancel button), a string of acceptable
   characters to mean OK and to mean Cancel.  The two last strings are checked
   to make sure they don't have common characters.  Additionally, the same
   flag argument as for the string input is taken, as well as a result buffer.
   The result buffer is required to be at least one byte long.  Depending on
   the answer, the first character from the OK or the Cancel character strings
   will be stored in the first byte of the result buffer.  No NUL will be
   added, so the result is *not* a string.

   On success, the all return an index of the added information.  That index
   is useful when retrieving results with UI_get0_result(). */
int UI_add_input_string(UI *ui, const char *prompt, int flags,
                        char *result_buf, int minsize, int maxsize);
int UI_dup_input_string(UI *ui, const char *prompt, int flags,
                        char *result_buf, int minsize, int maxsize);
int UI_add_verify_string(UI *ui, const char *prompt, int flags,
                         char *result_buf, int minsize, int maxsize,
                         const char *test_buf);
int UI_dup_verify_string(UI *ui, const char *prompt, int flags,
                         char *result_buf, int minsize, int maxsize,
                         const char *test_buf);
int UI_add_input_boolean(UI *ui, const char *prompt, const char *action_desc,
                         const char *ok_chars, const char *cancel_chars,
                         int flags, char *result_buf);
int UI_dup_input_boolean(UI *ui, const char *prompt, const char *action_desc,
                         const char *ok_chars, const char *cancel_chars,
                         int flags, char *result_buf);
int UI_add_info_string(UI *ui, const char *text);
int UI_dup_info_string(UI *ui, const char *text);
int UI_add_error_string(UI *ui, const char *text);
int UI_dup_error_string(UI *ui, const char *text);

/* These are the possible flags.  They can be or'ed together. */
/* Use to have echoing of input */
# define UI_INPUT_FLAG_ECHO              0x01
/*
 * Use a default password.  Where that password is found is completely up to
 * the application, it might for example be in the user data set with
 * UI_add_user_data().  It is not recommended to have more than one input in
 * each UI being marked with this flag, or the application might get
 * confused.
 */
# define UI_INPUT_FLAG_DEFAULT_PWD       0x02

/*-
 * The user of these routines may want to define flags of their own.  The core
 * UI won't look at those, but will pass them on to the method routines.  They
 * must use higher bits so they don't get confused with the UI bits above.
 * UI_INPUT_FLAG_USER_BASE tells which is the lowest bit to use.  A good
 * example of use is this:
 *
 *    #define MY_UI_FLAG1       (0x01 << UI_INPUT_FLAG_USER_BASE)
 *
*/
# define UI_INPUT_FLAG_USER_BASE 16

/*-
 * The following function helps construct a prompt.  object_desc is a
 * textual short description of the object, for example "pass phrase",
 * and object_name is the name of the object (might be a card name or
 * a file name.
 * The returned string shall always be allocated on the heap with
 * OPENSSL_malloc(), and need to be free'd with OPENSSL_free().
 *
 * If the ui_method doesn't contain a pointer to a user-defined prompt
 * constructor, a default string is built, looking like this:
 *
 *       "Enter {object_desc} for {object_name}:"
 *
 * So, if object_desc has the value "pass phrase" and object_name has
 * the value "foo.key", the resulting string is:
 *
 *       "Enter pass phrase for foo.key:"
*/
char *UI_construct_prompt(UI *ui_method,
                          const char *object_desc, const char *object_name);

/*
 * The following function is used to store a pointer to user-specific data.
 * Any previous such pointer will be returned and replaced.
 *
 * For callback purposes, this function makes a lot more sense than using
 * ex_data, since the latter requires that different parts of OpenSSL or
 * applications share the same ex_data index.
 *
 * Note that the UI_OpenSSL() method completely ignores the user data. Other
 * methods may not, however.
 */
void *UI_add_user_data(UI *ui, void *user_data);
/*
 * Alternatively, this function is used to duplicate the user data.
 * This uses the duplicator method function.  The destroy function will
 * be used to free the user data in this case.
 */
int UI_dup_user_data(UI *ui, void *user_data);
/* We need a user data retrieving function as well.  */
void *UI_get0_user_data(UI *ui);

/* Return the result associated with a prompt given with the index i. */
const char *UI_get0_result(UI *ui, int i);
int UI_get_result_length(UI *ui, int i);

/* When all strings have been added, process the whole thing. */
int UI_process(UI *ui);

/*
 * Give a user interface parameterised control commands.  This can be used to
 * send down an integer, a data pointer or a function pointer, as well as be
 * used to get information from a UI.
 */
int UI_ctrl(UI *ui, int cmd, long i, void *p, void (*f) (void));

/* The commands */
/*
 * Use UI_CONTROL_PRINT_ERRORS with the value 1 to have UI_process print the
 * OpenSSL error stack before printing any info or added error messages and
 * before any prompting.
 */
# define UI_CTRL_PRINT_ERRORS            1
/*
 * Check if a UI_process() is possible to do again with the same instance of
 * a user interface.  This makes UI_ctrl() return 1 if it is redoable, and 0
 * if not.
 */
# define UI_CTRL_IS_REDOABLE             2

/* Some methods may use extra data */
# define UI_set_app_data(s,arg)         UI_set_ex_data(s,0,arg)
# define UI_get_app_data(s)             UI_get_ex_data(s,0)

# define UI_get_ex_new_index(l, p, newf, dupf, freef) \
    CRYPTO_get_ex_new_index(CRYPTO_EX_INDEX_UI, l, p, newf, dupf, freef)
int UI_set_ex_data(UI *r, int idx, void *arg);
void *UI_get_ex_data(UI *r, int idx);

/* Use specific methods instead of the built-in one */
void UI_set_default_method(const UI_METHOD *meth);
const UI_METHOD *UI_get_default_method(void);
const UI_METHOD *UI_get_method(UI *ui);
const UI_METHOD *UI_set_method(UI *ui, const UI_METHOD *meth);

# ifndef OPENSSL_NO_UI_CONSOLE

/* The method with all the built-in thingies */
UI_METHOD *UI_OpenSSL(void);

# endif

/*
 * NULL method.  Literally does nothing, but may serve as a placeholder
 * to avoid internal default.
 */
const UI_METHOD *UI_null(void);

/* ---------- For method writers ---------- */
/*-
   A method contains a number of functions that implement the low level
   of the User Interface.  The functions are:

        an opener       This function starts a session, maybe by opening
                        a channel to a tty, or by opening a window.
        a writer        This function is called to write a given string,
                        maybe to the tty, maybe as a field label in a
                        window.
        a flusher       This function is called to flush everything that
                        has been output so far.  It can be used to actually
                        display a dialog box after it has been built.
        a reader        This function is called to read a given prompt,
                        maybe from the tty, maybe from a field in a
                        window.  Note that it's called with all string
                        structures, not only the prompt ones, so it must
                        check such things itself.
        a closer        This function closes the session, maybe by closing
                        the channel to the tty, or closing the window.

   All these functions are expected to return:

        0       on error.
        1       on success.
        -1      on out-of-band events, for example if some prompting has
                been canceled (by pressing Ctrl-C, for example).  This is
                only checked when returned by the flusher or the reader.

   The way this is used, the opener is first called, then the writer for all
   strings, then the flusher, then the reader for all strings and finally the
   closer.  Note that if you want to prompt from a terminal or other command
   line interface, the best is to have the reader also write the prompts
   instead of having the writer do it.  If you want to prompt from a dialog
   box, the writer can be used to build up the contents of the box, and the
   flusher to actually display the box and run the event loop until all data
   has been given, after which the reader only grabs the given data and puts
   them back into the UI strings.

   All method functions take a UI as argument.  Additionally, the writer and
   the reader take a UI_STRING.
*/

/*
 * The UI_STRING type is the data structure that contains all the needed info
 * about a string or a prompt, including test data for a verification prompt.
 */
typedef struct ui_string_st UI_STRING;
DEFINE_STACK_OF(UI_STRING)

/*
 * The different types of strings that are currently supported. This is only
 * needed by method authors.
 */
enum UI_string_types {
    UIT_NONE = 0,
    UIT_PROMPT,                 /* Prompt for a string */
    UIT_VERIFY,                 /* Prompt for a string and verify */
    UIT_BOOLEAN,                /* Prompt for a yes/no response */
    UIT_INFO,                   /* Send info to the user */
    UIT_ERROR                   /* Send an error message to the user */
};

/* Create and manipulate methods */
UI_METHOD *UI_create_method(const char *name);
void UI_destroy_method(UI_METHOD *ui_method);
int UI_method_set_opener(UI_METHOD *method, int (*opener) (UI *ui));
int UI_method_set_writer(UI_METHOD *method,
                         int (*writer) (UI *ui, UI_STRING *uis));
int UI_method_set_flusher(UI_METHOD *method, int (*flusher) (UI *ui));
int UI_method_set_reader(UI_METHOD *method,
                         int (*reader) (UI *ui, UI_STRING *uis));
int UI_method_set_closer(UI_METHOD *method, int (*closer) (UI *ui));
int UI_method_set_data_duplicator(UI_METHOD *method,
                                  void *(*duplicator) (UI *ui, void *ui_data),
                                  void (*destructor)(UI *ui, void *ui_data));
int UI_method_set_prompt_constructor(UI_METHOD *method,
                                     char *(*prompt_constructor) (UI *ui,
                                                                  const char
                                                                  *object_desc,
                                                                  const char
                                                                  *object_name));
int UI_method_set_ex_data(UI_METHOD *method, int idx, void *data);
int (*UI_method_get_opener(const UI_METHOD *method)) (UI *);
int (*UI_method_get_writer(const UI_METHOD *method)) (UI *, UI_STRING *);
int (*UI_method_get_flusher(const UI_METHOD *method)) (UI *);
int (*UI_method_get_reader(const UI_METHOD *method)) (UI *, UI_STRING *);
int (*UI_method_get_closer(const UI_METHOD *method)) (UI *);
char *(*UI_method_get_prompt_constructor(const UI_METHOD *method))
    (UI *, const char *, const char *);
void *(*UI_method_get_data_duplicator(const UI_METHOD *method)) (UI *, void *);
void (*UI_method_get_data_destructor(const UI_METHOD *method)) (UI *, void *);
const void *UI_method_get_ex_data(const UI_METHOD *method, int idx);

/*
 * The following functions are helpers for method writers to access relevant
 * data from a UI_STRING.
 */

/* Return type of the UI_STRING */
enum UI_string_types UI_get_string_type(UI_STRING *uis);
/* Return input flags of the UI_STRING */
int UI_get_input_flags(UI_STRING *uis);
/* Return the actual string to output (the prompt, info or error) */
const char *UI_get0_output_string(UI_STRING *uis);
/*
 * Return the optional action string to output (the boolean prompt
 * instruction)
 */
const char *UI_get0_action_string(UI_STRING *uis);
/* Return the result of a prompt */
const char *UI_get0_result_string(UI_STRING *uis);
int UI_get_result_string_length(UI_STRING *uis);
/*
 * Return the string to test the result against.  Only useful with verifies.
 */
const char *UI_get0_test_string(UI_STRING *uis);
/* Return the required minimum size of the result */
int UI_get_result_minsize(UI_STRING *uis);
/* Return the required maximum size of the result */
int UI_get_result_maxsize(UI_STRING *uis);
/* Set the result of a UI_STRING. */
int UI_set_result(UI *ui, UI_STRING *uis, const char *result);
int UI_set_result_ex(UI *ui, UI_STRING *uis, const char *result, int len);

/* A couple of popular utility functions */
int UI_UTIL_read_pw_string(char *buf, int length, const char *prompt,
                           int verify);
int UI_UTIL_read_pw(char *buf, char *buff, int size, const char *prompt,
                    int verify);
UI_METHOD *UI_UTIL_wrap_read_pem_callback(pem_password_cb *cb, int rwflag);


# ifdef  __cplusplus
}
# endif
#endif