menu.c 10 KB

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  1. // SPDX-License-Identifier: GPL-2.0+
  2. /*
  3. * Copyright 2010-2011 Calxeda, Inc.
  4. * Copyright (c) 2019, NVIDIA CORPORATION. All rights reserved.
  5. */
  6. #include <common.h>
  7. #include <cli.h>
  8. #include <malloc.h>
  9. #include <errno.h>
  10. #include <linux/list.h>
  11. #include "menu.h"
  12. /*
  13. * Internally, each item in a menu is represented by a struct menu_item.
  14. *
  15. * These items will be alloc'd and initialized by menu_item_add and destroyed
  16. * by menu_item_destroy, and the consumer of the interface never sees that
  17. * this struct is used at all.
  18. */
  19. struct menu_item {
  20. char *key;
  21. void *data;
  22. struct list_head list;
  23. };
  24. /*
  25. * The menu is composed of a list of items along with settings and callbacks
  26. * provided by the user. An incomplete definition of this struct is available
  27. * in menu.h, but the full definition is here to prevent consumers from
  28. * relying on its contents.
  29. */
  30. struct menu {
  31. struct menu_item *default_item;
  32. int timeout;
  33. char *title;
  34. int prompt;
  35. void (*display_statusline)(struct menu *);
  36. void (*item_data_print)(void *);
  37. char *(*item_choice)(void *);
  38. void *item_choice_data;
  39. struct list_head items;
  40. int item_cnt;
  41. };
  42. /*
  43. * An iterator function for menu items. callback will be called for each item
  44. * in m, with m, a pointer to the item, and extra being passed to callback. If
  45. * callback returns a value other than NULL, iteration stops and the value
  46. * return by callback is returned from menu_items_iter. This allows it to be
  47. * used for search type operations. It is also safe for callback to remove the
  48. * item from the list of items.
  49. */
  50. static inline void *menu_items_iter(struct menu *m,
  51. void *(*callback)(struct menu *, struct menu_item *, void *),
  52. void *extra)
  53. {
  54. struct list_head *pos, *n;
  55. struct menu_item *item;
  56. void *ret;
  57. list_for_each_safe(pos, n, &m->items) {
  58. item = list_entry(pos, struct menu_item, list);
  59. ret = callback(m, item, extra);
  60. if (ret)
  61. return ret;
  62. }
  63. return NULL;
  64. }
  65. /*
  66. * Print a menu_item. If the consumer provided an item_data_print function
  67. * when creating the menu, call it with a pointer to the item's private data.
  68. * Otherwise, print the key of the item.
  69. */
  70. static inline void *menu_item_print(struct menu *m,
  71. struct menu_item *item,
  72. void *extra)
  73. {
  74. if (!m->item_data_print) {
  75. puts(item->key);
  76. putc('\n');
  77. } else {
  78. m->item_data_print(item->data);
  79. }
  80. return NULL;
  81. }
  82. /*
  83. * Free the memory used by a menu item. This includes the memory used by its
  84. * key.
  85. */
  86. static inline void *menu_item_destroy(struct menu *m,
  87. struct menu_item *item,
  88. void *extra)
  89. {
  90. if (item->key)
  91. free(item->key);
  92. free(item);
  93. return NULL;
  94. }
  95. /*
  96. * Display a menu so the user can make a choice of an item. First display its
  97. * title, if any, and then each item in the menu.
  98. */
  99. static inline void menu_display(struct menu *m)
  100. {
  101. if (m->title) {
  102. puts(m->title);
  103. putc('\n');
  104. }
  105. if (m->display_statusline)
  106. m->display_statusline(m);
  107. menu_items_iter(m, menu_item_print, NULL);
  108. }
  109. /*
  110. * Check if an item's key matches a provided string, pointed to by extra. If
  111. * extra is NULL, an item with a NULL key will match. Otherwise, the item's
  112. * key has to match according to strcmp.
  113. *
  114. * This is called via menu_items_iter, so it returns a pointer to the item if
  115. * the key matches, and returns NULL otherwise.
  116. */
  117. static inline void *menu_item_key_match(struct menu *m,
  118. struct menu_item *item, void *extra)
  119. {
  120. char *item_key = extra;
  121. if (!item_key || !item->key) {
  122. if (item_key == item->key)
  123. return item;
  124. return NULL;
  125. }
  126. if (strcmp(item->key, item_key) == 0)
  127. return item;
  128. return NULL;
  129. }
  130. /*
  131. * Find the first item with a key matching item_key, if any exists.
  132. */
  133. static inline struct menu_item *menu_item_by_key(struct menu *m,
  134. char *item_key)
  135. {
  136. return menu_items_iter(m, menu_item_key_match, item_key);
  137. }
  138. /*
  139. * Set *choice to point to the default item's data, if any default item was
  140. * set, and returns 1. If no default item was set, returns -ENOENT.
  141. */
  142. int menu_default_choice(struct menu *m, void **choice)
  143. {
  144. if (m->default_item) {
  145. *choice = m->default_item->data;
  146. return 1;
  147. }
  148. return -ENOENT;
  149. }
  150. /*
  151. * Displays the menu and asks the user to choose an item. *choice will point
  152. * to the private data of the item the user chooses. The user makes a choice
  153. * by inputting a string matching the key of an item. Invalid choices will
  154. * cause the user to be prompted again, repeatedly, until the user makes a
  155. * valid choice. The user can exit the menu without making a choice via ^c.
  156. *
  157. * Returns 1 if the user made a choice, or -EINTR if they bail via ^c.
  158. */
  159. static inline int menu_interactive_choice(struct menu *m, void **choice)
  160. {
  161. char cbuf[CONFIG_SYS_CBSIZE];
  162. struct menu_item *choice_item = NULL;
  163. int readret;
  164. while (!choice_item) {
  165. cbuf[0] = '\0';
  166. menu_display(m);
  167. if (!m->item_choice) {
  168. readret = cli_readline_into_buffer("Enter choice: ",
  169. cbuf, m->timeout);
  170. if (readret >= 0) {
  171. choice_item = menu_item_by_key(m, cbuf);
  172. if (!choice_item)
  173. printf("%s not found\n", cbuf);
  174. } else if (readret == -1) {
  175. printf("<INTERRUPT>\n");
  176. return -EINTR;
  177. } else {
  178. return menu_default_choice(m, choice);
  179. }
  180. } else {
  181. char *key = m->item_choice(m->item_choice_data);
  182. if (key)
  183. choice_item = menu_item_by_key(m, key);
  184. }
  185. if (!choice_item)
  186. m->timeout = 0;
  187. }
  188. *choice = choice_item->data;
  189. return 1;
  190. }
  191. /*
  192. * menu_default_set() - Sets the default choice for the menu. This is safe to
  193. * call more than once on a menu.
  194. *
  195. * m - Points to a menu created by menu_create().
  196. *
  197. * item_key - Points to a string that, when compared using strcmp, matches the
  198. * key for an existing item in the menu.
  199. *
  200. * Returns 1 if successful, -EINVAL if m is NULL, or -ENOENT if no item with a
  201. * key matching item_key is found.
  202. */
  203. int menu_default_set(struct menu *m, char *item_key)
  204. {
  205. struct menu_item *item;
  206. if (!m)
  207. return -EINVAL;
  208. item = menu_item_by_key(m, item_key);
  209. if (!item)
  210. return -ENOENT;
  211. m->default_item = item;
  212. return 1;
  213. }
  214. /*
  215. * menu_get_choice() - Returns the user's selected menu entry, or the default
  216. * if the menu is set to not prompt or the timeout expires. This is safe to
  217. * call more than once.
  218. *
  219. * m - Points to a menu created by menu_create().
  220. *
  221. * choice - Points to a location that will store a pointer to the selected
  222. * menu item. If no item is selected or there is an error, no value will be
  223. * written at the location it points to.
  224. *
  225. * Returns 1 if successful, -EINVAL if m or choice is NULL, -ENOENT if no
  226. * default has been set and the menu is set to not prompt or the timeout
  227. * expires, or -EINTR if the user exits the menu via ^c.
  228. */
  229. int menu_get_choice(struct menu *m, void **choice)
  230. {
  231. if (!m || !choice)
  232. return -EINVAL;
  233. if (!m->prompt || m->item_cnt == 1)
  234. return menu_default_choice(m, choice);
  235. return menu_interactive_choice(m, choice);
  236. }
  237. /*
  238. * menu_item_add() - Adds or replaces a menu item. Note that this replaces the
  239. * data of an item if it already exists, but doesn't change the order of the
  240. * item.
  241. *
  242. * m - Points to a menu created by menu_create().
  243. *
  244. * item_key - Points to a string that will uniquely identify the item. The
  245. * string will be copied to internal storage, and is safe to discard after
  246. * passing to menu_item_add.
  247. *
  248. * item_data - An opaque pointer associated with an item. It is never
  249. * dereferenced internally, but will be passed to the item_data_print, and
  250. * will be returned from menu_get_choice if the menu item is selected.
  251. *
  252. * Returns 1 if successful, -EINVAL if m is NULL, or -ENOMEM if there is
  253. * insufficient memory to add the menu item.
  254. */
  255. int menu_item_add(struct menu *m, char *item_key, void *item_data)
  256. {
  257. struct menu_item *item;
  258. if (!m)
  259. return -EINVAL;
  260. item = menu_item_by_key(m, item_key);
  261. if (item) {
  262. item->data = item_data;
  263. return 1;
  264. }
  265. item = malloc(sizeof *item);
  266. if (!item)
  267. return -ENOMEM;
  268. item->key = strdup(item_key);
  269. if (!item->key) {
  270. free(item);
  271. return -ENOMEM;
  272. }
  273. item->data = item_data;
  274. list_add_tail(&item->list, &m->items);
  275. m->item_cnt++;
  276. return 1;
  277. }
  278. /*
  279. * menu_create() - Creates a menu handle with default settings
  280. *
  281. * title - If not NULL, points to a string that will be displayed before the
  282. * list of menu items. It will be copied to internal storage, and is safe to
  283. * discard after passing to menu_create().
  284. *
  285. * timeout - A delay in seconds to wait for user input. If 0, timeout is
  286. * disabled, and the default choice will be returned unless prompt is 1.
  287. *
  288. * prompt - If 0, don't ask for user input unless there is an interrupted
  289. * timeout. If 1, the user will be prompted for input regardless of the value
  290. * of timeout.
  291. *
  292. * display_statusline - If not NULL, will be called to show a statusline when
  293. * the menu is displayed.
  294. *
  295. * item_data_print - If not NULL, will be called for each item when the menu
  296. * is displayed, with the pointer to the item's data passed as the argument.
  297. * If NULL, each item's key will be printed instead. Since an item's key is
  298. * what must be entered to select an item, the item_data_print function should
  299. * make it obvious what the key for each entry is.
  300. *
  301. * item_choice - If not NULL, will be called when asking the user to choose an
  302. * item. Returns a key string corresponding to the chosen item or NULL if
  303. * no item has been selected.
  304. *
  305. * item_choice_data - Will be passed as the argument to the item_choice function
  306. *
  307. * Returns a pointer to the menu if successful, or NULL if there is
  308. * insufficient memory available to create the menu.
  309. */
  310. struct menu *menu_create(char *title, int timeout, int prompt,
  311. void (*display_statusline)(struct menu *),
  312. void (*item_data_print)(void *),
  313. char *(*item_choice)(void *),
  314. void *item_choice_data)
  315. {
  316. struct menu *m;
  317. m = malloc(sizeof *m);
  318. if (!m)
  319. return NULL;
  320. m->default_item = NULL;
  321. m->prompt = prompt;
  322. m->timeout = timeout;
  323. m->display_statusline = display_statusline;
  324. m->item_data_print = item_data_print;
  325. m->item_choice = item_choice;
  326. m->item_choice_data = item_choice_data;
  327. m->item_cnt = 0;
  328. if (title) {
  329. m->title = strdup(title);
  330. if (!m->title) {
  331. free(m);
  332. return NULL;
  333. }
  334. } else
  335. m->title = NULL;
  336. INIT_LIST_HEAD(&m->items);
  337. return m;
  338. }
  339. /*
  340. * menu_destroy() - frees the memory used by a menu and its items.
  341. *
  342. * m - Points to a menu created by menu_create().
  343. *
  344. * Returns 1 if successful, or -EINVAL if m is NULL.
  345. */
  346. int menu_destroy(struct menu *m)
  347. {
  348. if (!m)
  349. return -EINVAL;
  350. menu_items_iter(m, menu_item_destroy, NULL);
  351. if (m->title)
  352. free(m->title);
  353. free(m);
  354. return 1;
  355. }