menu.c 10 KB

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  1. // SPDX-License-Identifier: GPL-2.0+
  2. /*
  3. * Copyright 2010-2011 Calxeda, Inc.
  4. */
  5. #include <common.h>
  6. #include <cli.h>
  7. #include <malloc.h>
  8. #include <errno.h>
  9. #include <linux/list.h>
  10. #include "menu.h"
  11. /*
  12. * Internally, each item in a menu is represented by a struct menu_item.
  13. *
  14. * These items will be alloc'd and initialized by menu_item_add and destroyed
  15. * by menu_item_destroy, and the consumer of the interface never sees that
  16. * this struct is used at all.
  17. */
  18. struct menu_item {
  19. char *key;
  20. void *data;
  21. struct list_head list;
  22. };
  23. /*
  24. * The menu is composed of a list of items along with settings and callbacks
  25. * provided by the user. An incomplete definition of this struct is available
  26. * in menu.h, but the full definition is here to prevent consumers from
  27. * relying on its contents.
  28. */
  29. struct menu {
  30. struct menu_item *default_item;
  31. int timeout;
  32. char *title;
  33. int prompt;
  34. void (*item_data_print)(void *);
  35. char *(*item_choice)(void *);
  36. void *item_choice_data;
  37. struct list_head items;
  38. };
  39. /*
  40. * An iterator function for menu items. callback will be called for each item
  41. * in m, with m, a pointer to the item, and extra being passed to callback. If
  42. * callback returns a value other than NULL, iteration stops and the value
  43. * return by callback is returned from menu_items_iter. This allows it to be
  44. * used for search type operations. It is also safe for callback to remove the
  45. * item from the list of items.
  46. */
  47. static inline void *menu_items_iter(struct menu *m,
  48. void *(*callback)(struct menu *, struct menu_item *, void *),
  49. void *extra)
  50. {
  51. struct list_head *pos, *n;
  52. struct menu_item *item;
  53. void *ret;
  54. list_for_each_safe(pos, n, &m->items) {
  55. item = list_entry(pos, struct menu_item, list);
  56. ret = callback(m, item, extra);
  57. if (ret)
  58. return ret;
  59. }
  60. return NULL;
  61. }
  62. /*
  63. * Print a menu_item. If the consumer provided an item_data_print function
  64. * when creating the menu, call it with a pointer to the item's private data.
  65. * Otherwise, print the key of the item.
  66. */
  67. static inline void *menu_item_print(struct menu *m,
  68. struct menu_item *item,
  69. void *extra)
  70. {
  71. if (!m->item_data_print) {
  72. puts(item->key);
  73. putc('\n');
  74. } else {
  75. m->item_data_print(item->data);
  76. }
  77. return NULL;
  78. }
  79. /*
  80. * Free the memory used by a menu item. This includes the memory used by its
  81. * key.
  82. */
  83. static inline void *menu_item_destroy(struct menu *m,
  84. struct menu_item *item,
  85. void *extra)
  86. {
  87. if (item->key)
  88. free(item->key);
  89. free(item);
  90. return NULL;
  91. }
  92. __weak void menu_display_statusline(struct menu *m)
  93. {
  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. menu_display_statusline(m);
  106. menu_items_iter(m, menu_item_print, NULL);
  107. }
  108. /*
  109. * Check if an item's key matches a provided string, pointed to by extra. If
  110. * extra is NULL, an item with a NULL key will match. Otherwise, the item's
  111. * key has to match according to strcmp.
  112. *
  113. * This is called via menu_items_iter, so it returns a pointer to the item if
  114. * the key matches, and returns NULL otherwise.
  115. */
  116. static inline void *menu_item_key_match(struct menu *m,
  117. struct menu_item *item, void *extra)
  118. {
  119. char *item_key = extra;
  120. if (!item_key || !item->key) {
  121. if (item_key == item->key)
  122. return item;
  123. return NULL;
  124. }
  125. if (strcmp(item->key, item_key) == 0)
  126. return item;
  127. return NULL;
  128. }
  129. /*
  130. * Find the first item with a key matching item_key, if any exists.
  131. */
  132. static inline struct menu_item *menu_item_by_key(struct menu *m,
  133. char *item_key)
  134. {
  135. return menu_items_iter(m, menu_item_key_match, item_key);
  136. }
  137. /*
  138. * Set *choice to point to the default item's data, if any default item was
  139. * set, and returns 1. If no default item was set, returns -ENOENT.
  140. */
  141. int menu_default_choice(struct menu *m, void **choice)
  142. {
  143. if (m->default_item) {
  144. *choice = m->default_item->data;
  145. return 1;
  146. }
  147. return -ENOENT;
  148. }
  149. /*
  150. * Displays the menu and asks the user to choose an item. *choice will point
  151. * to the private data of the item the user chooses. The user makes a choice
  152. * by inputting a string matching the key of an item. Invalid choices will
  153. * cause the user to be prompted again, repeatedly, until the user makes a
  154. * valid choice. The user can exit the menu without making a choice via ^c.
  155. *
  156. * Returns 1 if the user made a choice, or -EINTR if they bail via ^c.
  157. */
  158. static inline int menu_interactive_choice(struct menu *m, void **choice)
  159. {
  160. char cbuf[CONFIG_SYS_CBSIZE];
  161. struct menu_item *choice_item = NULL;
  162. int readret;
  163. while (!choice_item) {
  164. cbuf[0] = '\0';
  165. menu_display(m);
  166. if (!m->item_choice) {
  167. readret = cli_readline_into_buffer("Enter choice: ",
  168. cbuf,
  169. m->timeout / 10);
  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)
  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. return 1;
  276. }
  277. /*
  278. * menu_create() - Creates a menu handle with default settings
  279. *
  280. * title - If not NULL, points to a string that will be displayed before the
  281. * list of menu items. It will be copied to internal storage, and is safe to
  282. * discard after passing to menu_create().
  283. *
  284. * timeout - A delay in seconds to wait for user input. If 0, timeout is
  285. * disabled, and the default choice will be returned unless prompt is 1.
  286. *
  287. * prompt - If 0, don't ask for user input unless there is an interrupted
  288. * timeout. If 1, the user will be prompted for input regardless of the value
  289. * of timeout.
  290. *
  291. * item_data_print - If not NULL, will be called for each item when the menu
  292. * is displayed, with the pointer to the item's data passed as the argument.
  293. * If NULL, each item's key will be printed instead. Since an item's key is
  294. * what must be entered to select an item, the item_data_print function should
  295. * make it obvious what the key for each entry is.
  296. *
  297. * item_choice - If not NULL, will be called when asking the user to choose an
  298. * item. Returns a key string corresponding to the chosen item or NULL if
  299. * no item has been selected.
  300. *
  301. * item_choice_data - Will be passed as the argument to the item_choice function
  302. *
  303. * Returns a pointer to the menu if successful, or NULL if there is
  304. * insufficient memory available to create the menu.
  305. */
  306. struct menu *menu_create(char *title, int timeout, int prompt,
  307. void (*item_data_print)(void *),
  308. char *(*item_choice)(void *),
  309. void *item_choice_data)
  310. {
  311. struct menu *m;
  312. m = malloc(sizeof *m);
  313. if (!m)
  314. return NULL;
  315. m->default_item = NULL;
  316. m->prompt = prompt;
  317. m->timeout = timeout;
  318. m->item_data_print = item_data_print;
  319. m->item_choice = item_choice;
  320. m->item_choice_data = item_choice_data;
  321. if (title) {
  322. m->title = strdup(title);
  323. if (!m->title) {
  324. free(m);
  325. return NULL;
  326. }
  327. } else
  328. m->title = NULL;
  329. INIT_LIST_HEAD(&m->items);
  330. return m;
  331. }
  332. /*
  333. * menu_destroy() - frees the memory used by a menu and its items.
  334. *
  335. * m - Points to a menu created by menu_create().
  336. *
  337. * Returns 1 if successful, or -EINVAL if m is NULL.
  338. */
  339. int menu_destroy(struct menu *m)
  340. {
  341. if (!m)
  342. return -EINVAL;
  343. menu_items_iter(m, menu_item_destroy, NULL);
  344. if (m->title)
  345. free(m->title);
  346. free(m);
  347. return 1;
  348. }