Provided by: libssl-doc_1.1.0g-2ubuntu4_all bug

NAME

       UI, UI_new, UI_new_method, UI_free, UI_add_input_string, UI_dup_input_string,
       UI_add_verify_string, UI_dup_verify_string, UI_add_input_boolean, UI_dup_input_boolean,
       UI_add_info_string, UI_dup_info_string, UI_add_error_string, UI_dup_error_string,
       UI_construct_prompt, UI_add_user_data, UI_get0_user_data, UI_get0_result, UI_process,
       UI_ctrl, UI_set_default_method, UI_get_default_method, UI_get_method, UI_set_method,
       UI_OpenSSL, UI_null - user interface

SYNOPSIS

        #include <openssl/ui.h>

        typedef struct ui_st UI;

        UI *UI_new(void);
        UI *UI_new_method(const UI_METHOD *method);
        void UI_free(UI *ui);

        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);

        char *UI_construct_prompt(UI *ui_method,
               const char *object_desc, const char *object_name);

        void *UI_add_user_data(UI *ui, void *user_data);
        void *UI_get0_user_data(UI *ui);

        const char *UI_get0_result(UI *ui, int i);

        int UI_process(UI *ui);

        int UI_ctrl(UI *ui, int cmd, long i, void *p, void (*f)());

        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);

        UI_METHOD *UI_OpenSSL(void);
        const UI_METHOD *UI_null(void);

DESCRIPTION

       UI stands for User Interface, and is general purpose set of routines to prompt the user
       for text-based information.  Through user-written methods (see UI_create_method(3)),
       prompting can be done in any way imaginable, be it plain text prompting, through dialog
       boxes or from a cell phone.

       All the functions work through a context of the type UI.  This context contains all the
       information needed to prompt correctly as well as a reference to a UI_METHOD, which is an
       ordered vector of functions that carry out the actual prompting.

       The first thing to do is to create a UI with UI_new() or UI_new_method(), then add
       information to it with the UI_add or UI_dup functions.  Also, user-defined random data can
       be passed down to the underlying method through calls to UI_add_user_data.  The default UI
       method doesn't care about these data, but other methods might.  Finally, use UI_process()
       to actually perform the prompting and UI_get0_result() to find the result to the prompt.

       A UI can contain more than one prompt, which are performed in the given sequence.  Each
       prompt gets an index number which is returned by the UI_add and UI_dup functions, and has
       to be used to get the corresponding result with UI_get0_result().

       The functions are as follows:

       UI_new() creates a new UI using the default UI method.  When done with this UI, it should
       be freed using UI_free().

       UI_new_method() creates a new UI using the given UI method.  When done with this UI, it
       should be freed using UI_free().

       UI_OpenSSL() returns the built-in UI method (note: not necessarely the default one, since
       the default can be changed.  See further on).  This method is the most machine/OS
       dependent part of OpenSSL and normally generates the most problems when porting.

       UI_null() returns a UI method that does nothing.  Its use is to avoid getting internal
       defaults for passed UI_METHOD pointers.

       UI_free() removes a UI from memory, along with all other pieces of memory that's connected
       to it, like duplicated input strings, results and others.  If ui is NULL nothing is done.

       UI_add_input_string() and UI_add_verify_string() add a prompt to the UI, as well as flags
       and a result buffer and the desired minimum and maximum sizes of the result, not counting
       the final NUL character.  The given information is used to prompt for information, for
       example a password, and to verify a password (i.e. having the user enter it twice and
       check that the same string was entered twice).  UI_add_verify_string() takes and extra
       argument that should be a pointer to the result buffer of the input string that it's
       supposed to verify, or verification will fail.

       UI_add_input_boolean() adds a prompt to the UI that's supposed to be answered in a boolean
       way, with a single character for yes and a different character for no.  A set of
       characters that can be used to cancel the prompt is given as well.  The prompt itself is
       divided in two, one part being the descriptive text (given through the prompt argument)
       and one describing the possible answers (given through the action_desc argument).

       UI_add_info_string() and UI_add_error_string() add strings that are shown at the same time
       as the prompt for extra information or to show an error string.  The difference between
       the two is only conceptual.  With the builtin method, there's no technical difference
       between them.  Other methods may make a difference between them, however.

       The flags currently supported are UI_INPUT_FLAG_ECHO, which is relevant for
       UI_add_input_string() and will have the users response be echoed (when prompting for a
       password, this flag should obviously not be used, and UI_INPUT_FLAG_DEFAULT_PWD, which
       means that a default password of some sort will be used (completely depending on the
       application and the UI method).

       UI_dup_input_string(), UI_dup_verify_string(), UI_dup_input_boolean(),
       UI_dup_info_string() and UI_dup_error_string() are basically the same as their UI_add
       counterparts, except that they make their own copies of all strings.

       UI_construct_prompt() is a helper function that can be used to create a prompt from two
       pieces of information: an description and a name.  The default constructor (if there is
       none provided by the method used) creates a string "Enter description for name:".  With
       the description "pass phrase" and the file name "foo.key", that becomes "Enter pass phrase
       for foo.key:".  Other methods may create whatever string and may include encodings that
       will be processed by the other method functions.

       UI_add_user_data() adds a piece of memory for the method to use at any time.  The builtin
       UI method doesn't care about this info.  Note that several calls to this function doesn't
       add data, it replaces the previous blob with the one given as argument.

       UI_get0_user_data() retrieves the data that has last been given to the UI with
       UI_add_user_data().

       UI_get0_result() returns a pointer to the result buffer associated with the information
       indexed by i.

       UI_process() goes through the information given so far, does all the printing and
       prompting and returns the final status, which is -2 on out-of-band events (Interrupt,
       Cancel, ...), -1 on error and 0 on success.

       UI_ctrl() adds extra control for the application author.  For now, it understands two
       commands: UI_CTRL_PRINT_ERRORS, which makes UI_process() print the OpenSSL error stack as
       part of processing the UI, and UI_CTRL_IS_REDOABLE, which returns a flag saying if the
       used UI can be used again or not.

       UI_set_default_method() changes the default UI method to the one given.  This function is
       not thread-safe and should not be called at the same time as other OpenSSL functions.

       UI_get_default_method() returns a pointer to the current default UI method.

       UI_get_method() returns the UI method associated with a given UI.

       UI_set_method() changes the UI method associated with a given UI.

NOTES

       The resulting strings that the built in method UI_OpenSSL() generate are assumed to be
       encoded according to the current locale or (for Windows) code page.  For applications
       having different demands, these strings need to be converted appropriately by the caller.
       For Windows, if the OPENSSL_WIN32_UTF8 environment variable is set, the built-in method
       UI_OpenSSL() will produce UTF-8 encoded strings instead.

COPYRIGHT

       Copyright 2001-2017 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>.