UI_NEW(3) FreeBSD Library Functions Manual UI_NEW(3)
NAME
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 - New User Interface
SYNOPSIS
#include <openssl/ui.h>
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);
/* These are the possible flags. They can be OR'ed together. */
#define UI_INPUT_FLAG_ECHO 0x01
#define UI_INPUT_FLAG_DEFAULT_PWD 0x02
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)());
#define UI_CTRL_PRINT_ERRORS 1
#define UI_CTRL_IS_REDOABLE 2
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);
const UI_METHOD *
UI_OpenSSL(void);
const UI_METHOD *
UI_null(void);
DESCRIPTION
UI stands for User Interface, and is a 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 necessarily 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 ui from memory, along with all other pieces of memory
that are connected to it, like duplicated input strings, results and
others. If ui is a NULL pointer, no action occurs.
UI_add_input_string() and UI_add_verify_string() add a prompt to 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 an
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 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 really 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: a 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 user data pointer 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 - the previous blob is
replaced 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, or 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.
RETURN VALUES
UI_new() and UI_new_method() return a valid UI structure or NULL if an
error occurred.
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(), and
UI_dup_error_string() return a positive number on success or a number
less than or equal to zero otherwise.
UI_construct_prompt() and UI_get0_result() return a string or NULL if an
error occurred.
UI_add_user_data() and UI_get0_user_data() return a pointer to the user
data that was contained in ui before the call. In particular, NULL is a
valid return value.
UI_process() returns 0 on success or a negative value on error.
UI_ctrl() returns a mask on success or -1 on error.
UI_get_default_method(), UI_OpenSSL() and UI_null() always return a
pointer to a valid UI_METHOD structure.
UI_get_method() and UI_set_method() return a pointer to the UI_METHOD
structure that is installed in ui after the call. The OpenSSL
documentation says that they can fail and return NULL, but currently,
this can only happen when and after UI_set_method() is called with an
explicit NULL argument.
SEE ALSO
crypto(3), UI_create_method(3), UI_get_string_type(3)
HISTORY
These functions first appeared in OpenSSL 0.9.7 and have been available
since OpenBSD 3.2.
UI_null() first appeared in OpenSSL 1.1.1 and has been available since
OpenBSD 7.3.
AUTHORS
Richard Levitte <
[email protected]> for the OpenSSL project.
FreeBSD 14.1-RELEASE-p8 March 9, 2025 FreeBSD 14.1-RELEASE-p8