UI_process
ui(3) OpenSSL ui(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_con-
struct_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, ERR_load_UI_strings - New
User Interface
SYNOPSIS
#include <openssl/ui.h>
typedef struct ui_st UI;
typedef struct ui_method_st UI_METHOD;
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);
UI_METHOD *UI_OpenSSL(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(3)), prompting can be done in any way imagin-
able, 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 corre-
sponding 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 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 gener-
ates the most problems when porting.
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.
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. 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 dif-
ferent character for no. A set of characters that can be used to can-
cel 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 rele-
vant 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 appli-
cation 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 func-
tions.
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 pre-
vious 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.
UI_ctrl() adds extra control for the application author. For now, it
understands two commands: UI_CTRL_PRINT_ERRORS, which makes UI_pro-
cess() 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.
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.
SEE ALSO
ui_create(3), ui_compat(3)
HISTORY
The UI section was first introduced in OpenSSL 0.9.7.
AUTHOR
Richard Levitte (richard@levitte.org) for the OpenSSL project
(http://www.openssl.org).
0.9.7a 2001-10-25 ui(3)
