UI_new.pod 11 KB

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  1. =pod
  2. =head1 NAME
  3. UI,
  4. UI_new, UI_new_method, UI_free, UI_add_input_string, UI_dup_input_string,
  5. UI_add_verify_string, UI_dup_verify_string, UI_add_input_boolean,
  6. UI_dup_input_boolean, UI_add_info_string, UI_dup_info_string,
  7. UI_add_error_string, UI_dup_error_string, UI_construct_prompt,
  8. UI_add_user_data, UI_dup_user_data, UI_get0_user_data, UI_get0_result,
  9. UI_get_result_length,
  10. UI_process, UI_ctrl, UI_set_default_method, UI_get_default_method,
  11. UI_get_method, UI_set_method, UI_OpenSSL, UI_null - user interface
  12. =head1 SYNOPSIS
  13. #include <openssl/ui.h>
  14. typedef struct ui_st UI;
  15. UI *UI_new(void);
  16. UI *UI_new_method(const UI_METHOD *method);
  17. void UI_free(UI *ui);
  18. int UI_add_input_string(UI *ui, const char *prompt, int flags,
  19. char *result_buf, int minsize, int maxsize);
  20. int UI_dup_input_string(UI *ui, const char *prompt, int flags,
  21. char *result_buf, int minsize, int maxsize);
  22. int UI_add_verify_string(UI *ui, const char *prompt, int flags,
  23. char *result_buf, int minsize, int maxsize,
  24. const char *test_buf);
  25. int UI_dup_verify_string(UI *ui, const char *prompt, int flags,
  26. char *result_buf, int minsize, int maxsize,
  27. const char *test_buf);
  28. int UI_add_input_boolean(UI *ui, const char *prompt, const char *action_desc,
  29. const char *ok_chars, const char *cancel_chars,
  30. int flags, char *result_buf);
  31. int UI_dup_input_boolean(UI *ui, const char *prompt, const char *action_desc,
  32. const char *ok_chars, const char *cancel_chars,
  33. int flags, char *result_buf);
  34. int UI_add_info_string(UI *ui, const char *text);
  35. int UI_dup_info_string(UI *ui, const char *text);
  36. int UI_add_error_string(UI *ui, const char *text);
  37. int UI_dup_error_string(UI *ui, const char *text);
  38. char *UI_construct_prompt(UI *ui_method,
  39. const char *phrase_desc, const char *object_name);
  40. void *UI_add_user_data(UI *ui, void *user_data);
  41. int UI_dup_user_data(UI *ui, void *user_data);
  42. void *UI_get0_user_data(UI *ui);
  43. const char *UI_get0_result(UI *ui, int i);
  44. int UI_get_result_length(UI *ui, int i);
  45. int UI_process(UI *ui);
  46. int UI_ctrl(UI *ui, int cmd, long i, void *p, void (*f)());
  47. void UI_set_default_method(const UI_METHOD *meth);
  48. const UI_METHOD *UI_get_default_method(void);
  49. const UI_METHOD *UI_get_method(UI *ui);
  50. const UI_METHOD *UI_set_method(UI *ui, const UI_METHOD *meth);
  51. UI_METHOD *UI_OpenSSL(void);
  52. const UI_METHOD *UI_null(void);
  53. =head1 DESCRIPTION
  54. UI stands for User Interface, and is general purpose set of routines to
  55. prompt the user for text-based information. Through user-written methods
  56. (see L<UI_create_method(3)>), prompting can be done in any way
  57. imaginable, be it plain text prompting, through dialog boxes or from a
  58. cell phone.
  59. All the functions work through a context of the type UI. This context
  60. contains all the information needed to prompt correctly as well as a
  61. reference to a UI_METHOD, which is an ordered vector of functions that
  62. carry out the actual prompting.
  63. The first thing to do is to create a UI with UI_new() or UI_new_method(),
  64. then add information to it with the UI_add or UI_dup functions. Also,
  65. user-defined random data can be passed down to the underlying method
  66. through calls to UI_add_user_data() or UI_dup_user_data(). The default
  67. UI method doesn't care about these data, but other methods might. Finally,
  68. use UI_process() to actually perform the prompting and UI_get0_result()
  69. and UI_get_result_length() to find the result to the prompt and its length.
  70. A UI can contain more than one prompt, which are performed in the given
  71. sequence. Each prompt gets an index number which is returned by the
  72. UI_add and UI_dup functions, and has to be used to get the corresponding
  73. result with UI_get0_result() and UI_get_result_length().
  74. UI_process() can be called more than once on the same UI, thereby allowing
  75. a UI to have a long lifetime, but can just as well have a short lifetime.
  76. The functions are as follows:
  77. UI_new() creates a new UI using the default UI method. When done with
  78. this UI, it should be freed using UI_free().
  79. UI_new_method() creates a new UI using the given UI method. When done with
  80. this UI, it should be freed using UI_free().
  81. UI_OpenSSL() returns the built-in UI method (note: not necessarily the
  82. default one, since the default can be changed. See further on). This
  83. method is the most machine/OS dependent part of OpenSSL and normally
  84. generates the most problems when porting.
  85. UI_null() returns a UI method that does nothing. Its use is to avoid
  86. getting internal defaults for passed UI_METHOD pointers.
  87. UI_free() removes a UI from memory, along with all other pieces of memory
  88. that's connected to it, like duplicated input strings, results and others.
  89. If B<ui> is NULL nothing is done.
  90. UI_add_input_string() and UI_add_verify_string() add a prompt to the UI,
  91. as well as flags and a result buffer and the desired minimum and maximum
  92. sizes of the result, not counting the final NUL character. The given
  93. information is used to prompt for information, for example a password,
  94. and to verify a password (i.e. having the user enter it twice and check
  95. that the same string was entered twice). UI_add_verify_string() takes
  96. and extra argument that should be a pointer to the result buffer of the
  97. input string that it's supposed to verify, or verification will fail.
  98. UI_add_input_boolean() adds a prompt to the UI that's supposed to be answered
  99. in a boolean way, with a single character for yes and a different character
  100. for no. A set of characters that can be used to cancel the prompt is given
  101. as well. The prompt itself is divided in two, one part being the
  102. descriptive text (given through the I<prompt> argument) and one describing
  103. the possible answers (given through the I<action_desc> argument).
  104. UI_add_info_string() and UI_add_error_string() add strings that are shown at
  105. the same time as the prompt for extra information or to show an error string.
  106. The difference between the two is only conceptual. With the built-in method,
  107. there's no technical difference between them. Other methods may make a
  108. difference between them, however.
  109. The flags currently supported are B<UI_INPUT_FLAG_ECHO>, which is relevant for
  110. UI_add_input_string() and will have the users response be echoed (when
  111. prompting for a password, this flag should obviously not be used, and
  112. B<UI_INPUT_FLAG_DEFAULT_PWD>, which means that a default password of some
  113. sort will be used (completely depending on the application and the UI
  114. method).
  115. UI_dup_input_string(), UI_dup_verify_string(), UI_dup_input_boolean(),
  116. UI_dup_info_string() and UI_dup_error_string() are basically the same
  117. as their UI_add counterparts, except that they make their own copies
  118. of all strings.
  119. UI_construct_prompt() is a helper function that can be used to create
  120. a prompt from two pieces of information: a phrase description I<phrase_desc>
  121. and an object name I<object_name>, where the latter may be NULL.
  122. The default constructor (if there is none provided by the method used)
  123. creates a string "Enter I<phrase_desc> for I<object_name>:"
  124. where the " for I<object_name>" part is left out if I<object_name> is NULL.
  125. With the description "pass phrase" and the filename "foo.key", that becomes
  126. "Enter pass phrase for foo.key:". Other methods may create whatever
  127. string and may include encodings that will be processed by the other
  128. method functions.
  129. UI_add_user_data() adds a user data pointer for the method to use at any
  130. time. The built-in UI method doesn't care about this info. Note that several
  131. calls to this function doesn't add data, it replaces the previous blob
  132. with the one given as argument.
  133. UI_dup_user_data() duplicates the user data and works as an alternative
  134. to UI_add_user_data() when the user data needs to be preserved for a longer
  135. duration, perhaps even the lifetime of the application. The UI object takes
  136. ownership of this duplicate and will free it whenever it gets replaced or
  137. the UI is destroyed. UI_dup_user_data() returns 0 on success, or -1 on memory
  138. allocation failure or if the method doesn't have a duplicator function.
  139. UI_get0_user_data() retrieves the data that has last been given to the
  140. UI with UI_add_user_data() or UI_dup_user_data.
  141. UI_get0_result() returns a pointer to the result buffer associated with
  142. the information indexed by I<i>.
  143. UI_get_result_length() returns the length of the result buffer associated with
  144. the information indexed by I<i>.
  145. UI_process() goes through the information given so far, does all the printing
  146. and prompting and returns the final status, which is -2 on out-of-band events
  147. (Interrupt, Cancel, ...), -1 on error and 0 on success.
  148. UI_ctrl() adds extra control for the application author. For now, it
  149. understands two commands: B<UI_CTRL_PRINT_ERRORS>, which makes UI_process()
  150. print the OpenSSL error stack as part of processing the UI, and
  151. B<UI_CTRL_IS_REDOABLE>, which returns a flag saying if the used UI can
  152. be used again or not.
  153. UI_set_default_method() changes the default UI method to the one given.
  154. This function is not thread-safe and should not be called at the same time
  155. as other OpenSSL functions.
  156. UI_get_default_method() returns a pointer to the current default UI method.
  157. UI_get_method() returns the UI method associated with a given UI.
  158. UI_set_method() changes the UI method associated with a given UI.
  159. =head1 NOTES
  160. The resulting strings that the built in method UI_OpenSSL() generate
  161. are assumed to be encoded according to the current locale or (for
  162. Windows) code page.
  163. For applications having different demands, these strings need to be
  164. converted appropriately by the caller.
  165. For Windows, if the B<OPENSSL_WIN32_UTF8> environment variable is set,
  166. the built-in method UI_OpenSSL() will produce UTF-8 encoded strings
  167. instead.
  168. =head1 RETURN VALUES
  169. UI_new() and UI_new_method() return a valid B<UI> structure or NULL if an error
  170. occurred.
  171. UI_add_input_string(), UI_dup_input_string(), UI_add_verify_string(),
  172. UI_dup_verify_string(), UI_add_input_boolean(), UI_dup_input_boolean(),
  173. UI_add_info_string(), UI_dup_info_string(), UI_add_error_string()
  174. and UI_dup_error_string() return a positive number on success or a value which
  175. is less than or equal to 0 otherwise.
  176. UI_construct_prompt() returns a string or NULL if an error occurred.
  177. UI_dup_user_data() returns 0 on success or -1 on error.
  178. UI_get0_result() returns a string or NULL on error.
  179. UI_get_result_length() returns a positive integer or 0 on success; otherwise it
  180. returns -1 on error.
  181. UI_process() returns 0 on success or a negative value on error.
  182. UI_ctrl() returns a mask on success or -1 on error.
  183. UI_get_default_method(), UI_get_method(), UI_OpenSSL(), UI_null() and
  184. UI_set_method() return either a valid B<UI_METHOD> structure or NULL
  185. respectively.
  186. =head1 HISTORY
  187. The UI_dup_user_data() function was added in OpenSSL 1.1.1.
  188. =head1 COPYRIGHT
  189. Copyright 2001-2018 The OpenSSL Project Authors. All Rights Reserved.
  190. Licensed under the Apache License 2.0 (the "License"). You may not use
  191. this file except in compliance with the License. You can obtain a copy
  192. in the file LICENSE in the source distribution or at
  193. L<https://www.openssl.org/source/license.html>.
  194. =cut