doc/man3/UI_new.pod - third_party/openssl - Git at Google

 =pod

 =head1 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_dup_user_data, UI_get0_user_data, UI_get0_result,
 UI_get_result_length,
 UI_process, UI_ctrl, UI_set_default_method, UI_get_default_method,
 UI_get_method, UI_set_method, UI_OpenSSL, UI_null - user interface

 =head1 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 *phrase_desc, const char *object_name);

  void *UI_add_user_data(UI *ui, void *user_data);
  int UI_dup_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_get_result_length(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);

 =head1 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 L<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() or UI_dup_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()
 and UI_get_result_length() to find the result to the prompt and its length.

 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() and UI_get_result_length().

 UI_process() can be called more than once on the same UI, thereby allowing
 a UI to have a long lifetime, but can just as well have a short lifetime.

 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 a UI from memory, along with all other pieces of memory
 that's connected to it, like duplicated input strings, results and others.
 If B<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 I<prompt> argument) and one describing
 the possible answers (given through the I<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 built-in method,
 there's no technical difference between them.  Other methods may make a
 difference between them, however.

 The flags currently supported are B<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
 B<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 phrase description I<phrase_desc>
 and an object name I<object_name>, where the latter may be NULL.
 The default constructor (if there is none provided by the method used)
 creates a string "Enter I<phrase_desc> for I<object_name>:"
 where the " for I<object_name>" part is left out if I<object_name> is NULL.
 With the description "pass phrase" and the filename "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 built-in 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_dup_user_data() duplicates the user data and works as an alternative
 to UI_add_user_data() when the user data needs to be preserved for a longer
 duration, perhaps even the lifetime of the application.  The UI object takes
 ownership of this duplicate and will free it whenever it gets replaced or
 the UI is destroyed.  UI_dup_user_data() returns 0 on success, or -1 on memory
 allocation failure or if the method doesn't have a duplicator function.

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

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

 UI_get_result_length() returns the length of the result buffer associated with
 the information indexed by I<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: B<UI_CTRL_PRINT_ERRORS>, which makes UI_process()
 print the OpenSSL error stack as part of processing the UI, and
 B<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.

 =head1 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 B<OPENSSL_WIN32_UTF8> environment variable is set,
 the built-in method UI_OpenSSL() will produce UTF-8 encoded strings
 instead.

 =head1 RETURN VALUES

 UI_new() and UI_new_method() return a valid B<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 value which
 is less than or equal to 0 otherwise.

 UI_construct_prompt() returns a string or NULL if an error occurred.

 UI_dup_user_data() returns 0 on success or -1 on error.

 UI_get0_result() returns a string or NULL on error.

 UI_get_result_length() returns a positive integer or 0 on success; otherwise it
 returns -1 on error.

 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_get_method(), UI_OpenSSL(), UI_null() and
 UI_set_method() return either a valid B<UI_METHOD> structure or NULL
 respectively.

 =head1 HISTORY

 The UI_dup_user_data() function was added in OpenSSL 1.1.1.

 =head1 COPYRIGHT

 Copyright 2001-2020 The OpenSSL Project Authors. All Rights Reserved.

 Licensed under the Apache License 2.0 (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
 L<https://www.openssl.org/source/license.html>.

 =cut
	=pod

	=head1 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_dup_user_data, UI_get0_user_data, UI_get0_result,
	UI_get_result_length,
	UI_process, UI_ctrl, UI_set_default_method, UI_get_default_method,
	UI_get_method, UI_set_method, UI_OpenSSL, UI_null - user interface

	=head1 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 phrase_desc, const char object_name);

	void UI_add_user_data(UI ui, void *user_data);
	int UI_dup_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_get_result_length(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);

	=head1 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 L<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() or UI_dup_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()
	and UI_get_result_length() to find the result to the prompt and its length.

	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() and UI_get_result_length().

	UI_process() can be called more than once on the same UI, thereby allowing
	a UI to have a long lifetime, but can just as well have a short lifetime.

	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 a UI from memory, along with all other pieces of memory
	that's connected to it, like duplicated input strings, results and others.
	If B<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 I<prompt> argument) and one describing
	the possible answers (given through the I<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 built-in method,
	there's no technical difference between them. Other methods may make a
	difference between them, however.

	The flags currently supported are B<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
	B<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 phrase description I<phrase_desc>
	and an object name I<object_name>, where the latter may be NULL.
	The default constructor (if there is none provided by the method used)
	creates a string "Enter I<phrase_desc> for I<object_name>:"
	where the " for I<object_name>" part is left out if I<object_name> is NULL.
	With the description "pass phrase" and the filename "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 built-in 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_dup_user_data() duplicates the user data and works as an alternative
	to UI_add_user_data() when the user data needs to be preserved for a longer
	duration, perhaps even the lifetime of the application. The UI object takes
	ownership of this duplicate and will free it whenever it gets replaced or
	the UI is destroyed. UI_dup_user_data() returns 0 on success, or -1 on memory
	allocation failure or if the method doesn't have a duplicator function.

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

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

	UI_get_result_length() returns the length of the result buffer associated with
	the information indexed by I<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: B<UI_CTRL_PRINT_ERRORS>, which makes UI_process()
	print the OpenSSL error stack as part of processing the UI, and
	B<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.

	=head1 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 B<OPENSSL_WIN32_UTF8> environment variable is set,
	the built-in method UI_OpenSSL() will produce UTF-8 encoded strings
	instead.

	=head1 RETURN VALUES

	UI_new() and UI_new_method() return a valid B<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 value which
	is less than or equal to 0 otherwise.

	UI_construct_prompt() returns a string or NULL if an error occurred.

	UI_dup_user_data() returns 0 on success or -1 on error.

	UI_get0_result() returns a string or NULL on error.

	UI_get_result_length() returns a positive integer or 0 on success; otherwise it
	returns -1 on error.

	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_get_method(), UI_OpenSSL(), UI_null() and
	UI_set_method() return either a valid B<UI_METHOD> structure or NULL
	respectively.

	=head1 HISTORY

	The UI_dup_user_data() function was added in OpenSSL 1.1.1.

	=head1 COPYRIGHT

	Copyright 2001-2020 The OpenSSL Project Authors. All Rights Reserved.

	Licensed under the Apache License 2.0 (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
	L<https://www.openssl.org/source/license.html>.

	=cut