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