mirror of https://github.com/openssl/openssl.git
				
				
				
			
		
			
				
	
	
		
			256 lines
		
	
	
		
			11 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
			
		
		
	
	
			256 lines
		
	
	
		
			11 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
=pod
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=head1 NAME
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UI,
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UI_new, UI_new_method, UI_free, UI_add_input_string, UI_dup_input_string,
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UI_add_verify_string, UI_dup_verify_string, UI_add_input_boolean,
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UI_dup_input_boolean, UI_add_info_string, UI_dup_info_string,
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UI_add_error_string, UI_dup_error_string, UI_construct_prompt,
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UI_add_user_data, UI_dup_user_data, UI_get0_user_data, UI_get0_result,
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UI_get_result_length,
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UI_process, UI_ctrl, UI_set_default_method, UI_get_default_method,
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UI_get_method, UI_set_method, UI_OpenSSL, UI_null - user interface
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=head1 SYNOPSIS
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 #include <openssl/ui.h>
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 typedef struct ui_st UI;
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 UI *UI_new(void);
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 UI *UI_new_method(const UI_METHOD *method);
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 void UI_free(UI *ui);
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 int UI_add_input_string(UI *ui, const char *prompt, int flags,
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                         char *result_buf, int minsize, int maxsize);
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 int UI_dup_input_string(UI *ui, const char *prompt, int flags,
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                         char *result_buf, int minsize, int maxsize);
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 int UI_add_verify_string(UI *ui, const char *prompt, int flags,
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                          char *result_buf, int minsize, int maxsize,
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                          const char *test_buf);
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 int UI_dup_verify_string(UI *ui, const char *prompt, int flags,
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                          char *result_buf, int minsize, int maxsize,
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                          const char *test_buf);
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 int UI_add_input_boolean(UI *ui, const char *prompt, const char *action_desc,
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                          const char *ok_chars, const char *cancel_chars,
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                          int flags, char *result_buf);
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 int UI_dup_input_boolean(UI *ui, const char *prompt, const char *action_desc,
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                          const char *ok_chars, const char *cancel_chars,
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                          int flags, char *result_buf);
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 int UI_add_info_string(UI *ui, const char *text);
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 int UI_dup_info_string(UI *ui, const char *text);
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 int UI_add_error_string(UI *ui, const char *text);
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 int UI_dup_error_string(UI *ui, const char *text);
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 char *UI_construct_prompt(UI *ui_method,
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                           const char *phrase_desc, const char *object_name);
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 void *UI_add_user_data(UI *ui, void *user_data);
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 int UI_dup_user_data(UI *ui, void *user_data);
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 void *UI_get0_user_data(UI *ui);
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 const char *UI_get0_result(UI *ui, int i);
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 int UI_get_result_length(UI *ui, int i);
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 int UI_process(UI *ui);
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 int UI_ctrl(UI *ui, int cmd, long i, void *p, void (*f)());
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 void UI_set_default_method(const UI_METHOD *meth);
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 const UI_METHOD *UI_get_default_method(void);
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 const UI_METHOD *UI_get_method(UI *ui);
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 const UI_METHOD *UI_set_method(UI *ui, const UI_METHOD *meth);
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 UI_METHOD *UI_OpenSSL(void);
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 const UI_METHOD *UI_null(void);
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=head1 DESCRIPTION
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UI stands for User Interface, and is general purpose set of routines to
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prompt the user for text-based information.  Through user-written methods
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(see L<UI_create_method(3)>), prompting can be done in any way
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imaginable, be it plain text prompting, through dialog boxes or from a
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cell phone.
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All the functions work through a context of the type UI.  This context
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contains all the information needed to prompt correctly as well as a
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reference to a UI_METHOD, which is an ordered vector of functions that
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carry out the actual prompting.
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The first thing to do is to create a UI with UI_new() or UI_new_method(),
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then add information to it with the UI_add or UI_dup functions.  Also,
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user-defined random data can be passed down to the underlying method
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through calls to UI_add_user_data() or UI_dup_user_data().  The default
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UI method doesn't care about these data, but other methods might.  Finally,
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use UI_process() to actually perform the prompting and UI_get0_result()
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and UI_get_result_length() to find the result to the prompt and its length.
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A UI can contain more than one prompt, which are performed in the given
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sequence.  Each prompt gets an index number which is returned by the
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UI_add and UI_dup functions, and has to be used to get the corresponding
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result with UI_get0_result() and UI_get_result_length().
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UI_process() can be called more than once on the same UI, thereby allowing
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a UI to have a long lifetime, but can just as well have a short lifetime.
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The functions are as follows:
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UI_new() creates a new UI using the default UI method.  When done with
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this UI, it should be freed using UI_free().
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UI_new_method() creates a new UI using the given UI method.  When done with
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this UI, it should be freed using UI_free().
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UI_OpenSSL() returns the built-in UI method (note: not necessarily the
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default one, since the default can be changed.  See further on).  This
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method is the most machine/OS dependent part of OpenSSL and normally
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generates the most problems when porting.
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UI_null() returns a UI method that does nothing.  Its use is to avoid
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getting internal defaults for passed UI_METHOD pointers.
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UI_free() removes a UI from memory, along with all other pieces of memory
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that's connected to it, like duplicated input strings, results and others.
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If B<ui> is NULL nothing is done.
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UI_add_input_string() and UI_add_verify_string() add a prompt to the UI,
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as well as flags and a result buffer and the desired minimum and maximum
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sizes of the result, not counting the final NUL character.  The given
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information is used to prompt for information, for example a password,
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and to verify a password (i.e. having the user enter it twice and check
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that the same string was entered twice).  UI_add_verify_string() takes
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and extra argument that should be a pointer to the result buffer of the
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input string that it's supposed to verify, or verification will fail.
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UI_add_input_boolean() adds a prompt to the UI that's supposed to be answered
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in a boolean way, with a single character for yes and a different character
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for no.  A set of characters that can be used to cancel the prompt is given
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as well.  The prompt itself is divided in two, one part being the
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descriptive text (given through the I<prompt> argument) and one describing
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the possible answers (given through the I<action_desc> argument).
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UI_add_info_string() and UI_add_error_string() add strings that are shown at
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the same time as the prompt for extra information or to show an error string.
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The difference between the two is only conceptual.  With the built-in method,
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there's no technical difference between them.  Other methods may make a
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difference between them, however.
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The flags currently supported are B<UI_INPUT_FLAG_ECHO>, which is relevant for
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UI_add_input_string() and will have the users response be echoed (when
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prompting for a password, this flag should obviously not be used, and
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B<UI_INPUT_FLAG_DEFAULT_PWD>, which means that a default password of some
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sort will be used (completely depending on the application and the UI
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method).
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UI_dup_input_string(), UI_dup_verify_string(), UI_dup_input_boolean(),
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UI_dup_info_string() and UI_dup_error_string() are basically the same
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as their UI_add counterparts, except that they make their own copies
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of all strings.
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UI_construct_prompt() is a helper function that can be used to create
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a prompt from two pieces of information: a phrase description I<phrase_desc>
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and an object name I<object_name>, where the latter may be NULL.
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The default constructor (if there is none provided by the method used)
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creates a string "Enter I<phrase_desc> for I<object_name>:"
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where the " for I<object_name>" part is left out if I<object_name> is NULL.
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With the description "pass phrase" and the filename "foo.key", that becomes
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"Enter pass phrase for foo.key:".  Other methods may create whatever
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string and may include encodings that will be processed by the other
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method functions.
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UI_add_user_data() adds a user data pointer for the method to use at any
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time.  The built-in UI method doesn't care about this info.  Note that several
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calls to this function doesn't add data, it replaces the previous blob
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with the one given as argument.
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UI_dup_user_data() duplicates the user data and works as an alternative
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to UI_add_user_data() when the user data needs to be preserved for a longer
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duration, perhaps even the lifetime of the application.  The UI object takes
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ownership of this duplicate and will free it whenever it gets replaced or
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the UI is destroyed.  UI_dup_user_data() returns 0 on success, or -1 on memory
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allocation failure or if the method doesn't have a duplicator function.
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UI_get0_user_data() retrieves the data that has last been given to the
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UI with UI_add_user_data() or UI_dup_user_data.
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UI_get0_result() returns a pointer to the result buffer associated with
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the information indexed by I<i>.
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UI_get_result_length() returns the length of the result buffer associated with
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the information indexed by I<i>.
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UI_process() goes through the information given so far, does all the printing
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and prompting and returns the final status, which is -2 on out-of-band events
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(Interrupt, Cancel, ...), -1 on error and 0 on success.
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UI_ctrl() adds extra control for the application author.  For now, it
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understands two commands: B<UI_CTRL_PRINT_ERRORS>, which makes UI_process()
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print the OpenSSL error stack as part of processing the UI, and
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B<UI_CTRL_IS_REDOABLE>, which returns a flag saying if the used UI can
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be used again or not.
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UI_set_default_method() changes the default UI method to the one given.
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This function is not thread-safe and should not be called at the same time
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as other OpenSSL functions.
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UI_get_default_method() returns a pointer to the current default UI method.
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UI_get_method() returns the UI method associated with a given UI.
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UI_set_method() changes the UI method associated with a given UI.
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=head1 NOTES
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The resulting strings that the built in method UI_OpenSSL() generate
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are assumed to be encoded according to the current locale or (for
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Windows) code page.
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For applications having different demands, these strings need to be
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converted appropriately by the caller.
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For Windows, if the B<OPENSSL_WIN32_UTF8> environment variable is set,
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the built-in method UI_OpenSSL() will produce UTF-8 encoded strings
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instead.
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=head1 RETURN VALUES
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UI_new() and UI_new_method() return a valid B<UI> structure or NULL if an error
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occurred.
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UI_add_input_string(), UI_dup_input_string(), UI_add_verify_string(),
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UI_dup_verify_string(), UI_add_input_boolean(), UI_dup_input_boolean(),
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UI_add_info_string(), UI_dup_info_string(), UI_add_error_string()
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and UI_dup_error_string() return a positive number on success or a value which
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is less than or equal to 0 otherwise.
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UI_construct_prompt() returns a string or NULL if an error occurred.
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UI_dup_user_data() returns 0 on success or -1 on error.
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UI_get0_result() returns a string or NULL on error.
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UI_get_result_length() returns a positive integer or 0 on success; otherwise it
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returns -1 on error.
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UI_process() returns 0 on success or a negative value on error.
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UI_ctrl() returns a mask on success or -1 on error.
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UI_get_default_method(), UI_get_method(), UI_OpenSSL(), UI_null() and
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UI_set_method() return either a valid B<UI_METHOD> structure or NULL
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respectively.
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=head1 HISTORY
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The UI_dup_user_data() function was added in OpenSSL 1.1.1.
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=head1 COPYRIGHT
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Copyright 2001-2020 The OpenSSL Project Authors. All Rights Reserved.
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Licensed under the Apache License 2.0 (the "License").  You may not use
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this file except in compliance with the License.  You can obtain a copy
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in the file LICENSE in the source distribution or at
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L<https://www.openssl.org/source/license.html>.
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=cut
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