xref: /openssl/doc/man3/UI_new.pod (revision eec0ad10) 
1=pod
2
3=head1 NAME
4
5UI,
6UI_new, UI_new_method, UI_free, UI_add_input_string, UI_dup_input_string,
7UI_add_verify_string, UI_dup_verify_string, UI_add_input_boolean,
8UI_dup_input_boolean, UI_add_info_string, UI_dup_info_string,
9UI_add_error_string, UI_dup_error_string, UI_construct_prompt,
10UI_add_user_data, UI_dup_user_data, UI_get0_user_data, UI_get0_result,
11UI_get_result_length,
12UI_process, UI_ctrl, UI_set_default_method, UI_get_default_method,
13UI_get_method, UI_set_method, UI_OpenSSL, UI_null - user interface
14
15=head1 SYNOPSIS
16
17 #include <openssl/ui.h>
18
19 typedef struct ui_st UI;
20
21 UI *UI_new(void);
22 UI *UI_new_method(const UI_METHOD *method);
23 void UI_free(UI *ui);
24
25 int UI_add_input_string(UI *ui, const char *prompt, int flags,
26                         char *result_buf, int minsize, int maxsize);
27 int UI_dup_input_string(UI *ui, const char *prompt, int flags,
28                         char *result_buf, int minsize, int maxsize);
29 int UI_add_verify_string(UI *ui, const char *prompt, int flags,
30                          char *result_buf, int minsize, int maxsize,
31                          const char *test_buf);
32 int UI_dup_verify_string(UI *ui, const char *prompt, int flags,
33                          char *result_buf, int minsize, int maxsize,
34                          const char *test_buf);
35 int UI_add_input_boolean(UI *ui, const char *prompt, const char *action_desc,
36                          const char *ok_chars, const char *cancel_chars,
37                          int flags, char *result_buf);
38 int UI_dup_input_boolean(UI *ui, const char *prompt, const char *action_desc,
39                          const char *ok_chars, const char *cancel_chars,
40                          int flags, char *result_buf);
41 int UI_add_info_string(UI *ui, const char *text);
42 int UI_dup_info_string(UI *ui, const char *text);
43 int UI_add_error_string(UI *ui, const char *text);
44 int UI_dup_error_string(UI *ui, const char *text);
45
46 char *UI_construct_prompt(UI *ui_method,
47                           const char *phrase_desc, const char *object_name);
48
49 void *UI_add_user_data(UI *ui, void *user_data);
50 int UI_dup_user_data(UI *ui, void *user_data);
51 void *UI_get0_user_data(UI *ui);
52
53 const char *UI_get0_result(UI *ui, int i);
54 int UI_get_result_length(UI *ui, int i);
55
56 int UI_process(UI *ui);
57
58 int UI_ctrl(UI *ui, int cmd, long i, void *p, void (*f)());
59
60 void UI_set_default_method(const UI_METHOD *meth);
61 const UI_METHOD *UI_get_default_method(void);
62 const UI_METHOD *UI_get_method(UI *ui);
63 const UI_METHOD *UI_set_method(UI *ui, const UI_METHOD *meth);
64
65 UI_METHOD *UI_OpenSSL(void);
66 const UI_METHOD *UI_null(void);
67
68=head1 DESCRIPTION
69
70UI stands for User Interface, and is general purpose set of routines to
71prompt the user for text-based information.  Through user-written methods
72(see L<UI_create_method(3)>), prompting can be done in any way
73imaginable, be it plain text prompting, through dialog boxes or from a
74cell phone.
75
76All the functions work through a context of the type UI.  This context
77contains all the information needed to prompt correctly as well as a
78reference to a UI_METHOD, which is an ordered vector of functions that
79carry out the actual prompting.
80
81The first thing to do is to create a UI with UI_new() or UI_new_method(),
82then add information to it with the UI_add or UI_dup functions.  Also,
83user-defined random data can be passed down to the underlying method
84through calls to UI_add_user_data() or UI_dup_user_data().  The default
85UI method doesn't care about these data, but other methods might.  Finally,
86use UI_process() to actually perform the prompting and UI_get0_result()
87and UI_get_result_length() to find the result to the prompt and its length.
88
89A UI can contain more than one prompt, which are performed in the given
90sequence.  Each prompt gets an index number which is returned by the
91UI_add and UI_dup functions, and has to be used to get the corresponding
92result with UI_get0_result() and UI_get_result_length().
93
94UI_process() can be called more than once on the same UI, thereby allowing
95a UI to have a long lifetime, but can just as well have a short lifetime.
96
97The functions are as follows:
98
99UI_new() creates a new UI using the default UI method.  When done with
100this UI, it should be freed using UI_free().
101
102UI_new_method() creates a new UI using the given UI method.  When done with
103this UI, it should be freed using UI_free().
104
105UI_OpenSSL() returns the built-in UI method (note: not necessarily the
106default one, since the default can be changed.  See further on).  This
107method is the most machine/OS dependent part of OpenSSL and normally
108generates the most problems when porting.
109
110UI_null() returns a UI method that does nothing.  Its use is to avoid
111getting internal defaults for passed UI_METHOD pointers.
112
113UI_free() removes a UI from memory, along with all other pieces of memory
114that's connected to it, like duplicated input strings, results and others.
115If B<ui> is NULL nothing is done.
116
117UI_add_input_string() and UI_add_verify_string() add a prompt to the UI,
118as well as flags and a result buffer and the desired minimum and maximum
119sizes of the result, not counting the final NUL character.  The given
120information is used to prompt for information, for example a password,
121and to verify a password (i.e. having the user enter it twice and check
122that the same string was entered twice).  UI_add_verify_string() takes
123and extra argument that should be a pointer to the result buffer of the
124input string that it's supposed to verify, or verification will fail.
125
126UI_add_input_boolean() adds a prompt to the UI that's supposed to be answered
127in a boolean way, with a single character for yes and a different character
128for no.  A set of characters that can be used to cancel the prompt is given
129as well.  The prompt itself is divided in two, one part being the
130descriptive text (given through the I<prompt> argument) and one describing
131the possible answers (given through the I<action_desc> argument).
132
133UI_add_info_string() and UI_add_error_string() add strings that are shown at
134the same time as the prompt for extra information or to show an error string.
135The difference between the two is only conceptual.  With the built-in method,
136there's no technical difference between them.  Other methods may make a
137difference between them, however.
138
139The flags currently supported are B<UI_INPUT_FLAG_ECHO>, which is relevant for
140UI_add_input_string() and will have the users response be echoed (when
141prompting for a password, this flag should obviously not be used, and
142B<UI_INPUT_FLAG_DEFAULT_PWD>, which means that a default password of some
143sort will be used (completely depending on the application and the UI
144method).
145
146UI_dup_input_string(), UI_dup_verify_string(), UI_dup_input_boolean(),
147UI_dup_info_string() and UI_dup_error_string() are basically the same
148as their UI_add counterparts, except that they make their own copies
149of all strings.
150
151UI_construct_prompt() is a helper function that can be used to create
152a prompt from two pieces of information: a phrase description I<phrase_desc>
153and an object name I<object_name>, where the latter may be NULL.
154The default constructor (if there is none provided by the method used)
155creates a string "Enter I<phrase_desc> for I<object_name>:"
156where the " for I<object_name>" part is left out if I<object_name> is NULL.
157With the description "pass phrase" and the filename "foo.key", that becomes
158"Enter pass phrase for foo.key:".  Other methods may create whatever
159string and may include encodings that will be processed by the other
160method functions.
161
162UI_add_user_data() adds a user data pointer for the method to use at any
163time.  The built-in UI method doesn't care about this info.  Note that several
164calls to this function doesn't add data, it replaces the previous blob
165with the one given as argument.
166
167UI_dup_user_data() duplicates the user data and works as an alternative
168to UI_add_user_data() when the user data needs to be preserved for a longer
169duration, perhaps even the lifetime of the application.  The UI object takes
170ownership of this duplicate and will free it whenever it gets replaced or
171the UI is destroyed.  UI_dup_user_data() returns 0 on success, or -1 on memory
172allocation failure or if the method doesn't have a duplicator function.
173
174UI_get0_user_data() retrieves the data that has last been given to the
175UI with UI_add_user_data() or UI_dup_user_data.
176
177UI_get0_result() returns a pointer to the result buffer associated with
178the information indexed by I<i>.
179
180UI_get_result_length() returns the length of the result buffer associated with
181the information indexed by I<i>.
182
183UI_process() goes through the information given so far, does all the printing
184and prompting and returns the final status, which is -2 on out-of-band events
185(Interrupt, Cancel, ...), -1 on error and 0 on success.
186
187UI_ctrl() adds extra control for the application author.  For now, it
188understands two commands: B<UI_CTRL_PRINT_ERRORS>, which makes UI_process()
189print the OpenSSL error stack as part of processing the UI, and
190B<UI_CTRL_IS_REDOABLE>, which returns a flag saying if the used UI can
191be used again or not.
192
193UI_set_default_method() changes the default UI method to the one given.
194This function is not thread-safe and should not be called at the same time
195as other OpenSSL functions.
196
197UI_get_default_method() returns a pointer to the current default UI method.
198
199UI_get_method() returns the UI method associated with a given UI.
200
201UI_set_method() changes the UI method associated with a given UI.
202
203=head1 NOTES
204
205The resulting strings that the built in method UI_OpenSSL() generate
206are assumed to be encoded according to the current locale or (for
207Windows) code page.
208For applications having different demands, these strings need to be
209converted appropriately by the caller.
210For Windows, if the B<OPENSSL_WIN32_UTF8> environment variable is set,
211the built-in method UI_OpenSSL() will produce UTF-8 encoded strings
212instead.
213
214=head1 RETURN VALUES
215
216UI_new() and UI_new_method() return a valid B<UI> structure or NULL if an error
217occurred.
218
219UI_add_input_string(), UI_dup_input_string(), UI_add_verify_string(),
220UI_dup_verify_string(), UI_add_input_boolean(), UI_dup_input_boolean(),
221UI_add_info_string(), UI_dup_info_string(), UI_add_error_string()
222and UI_dup_error_string() return a positive number on success or a value which
223is less than or equal to 0 otherwise.
224
225UI_construct_prompt() returns a string or NULL if an error occurred.
226
227UI_dup_user_data() returns 0 on success or -1 on error.
228
229UI_get0_result() returns a string or NULL on error.
230
231UI_get_result_length() returns a positive integer or 0 on success; otherwise it
232returns -1 on error.
233
234UI_process() returns 0 on success or a negative value on error.
235
236UI_ctrl() returns a mask on success or -1 on error.
237
238UI_get_default_method(), UI_get_method(), UI_OpenSSL(), UI_null() and
239UI_set_method() return either a valid B<UI_METHOD> structure or NULL
240respectively.
241
242=head1 HISTORY
243
244The UI_dup_user_data() function was added in OpenSSL 1.1.1.
245
246=head1 COPYRIGHT
247
248Copyright 2001-2020 The OpenSSL Project Authors. All Rights Reserved.
249
250Licensed under the Apache License 2.0 (the "License").  You may not use
251this file except in compliance with the License.  You can obtain a copy
252in the file LICENSE in the source distribution or at
253L<https://www.openssl.org/source/license.html>.
254
255=cut
256