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shell_expat.c 11 KB

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  1. /*
  2. * ------------------------------------------------------
  3. * shell_expat.c
  4. *
  5. * This file implements the means to read an XML encoded file
  6. * and populate the CLI tree based on the contents. It implements
  7. * the clish_xml API using the expat XML parser
  8. *
  9. * expat is not your typicall XML parser. It does not work
  10. * by creating a full in-memory XML tree, but by calling specific
  11. * callbacks (element handlers) regularly while parsing. It's up
  12. * to the user to create the corresponding XML tree if needed
  13. * (obviously, this is what we're doing, as we really need the XML
  14. * tree in klish).
  15. *
  16. * The code below do that. It transforms the output of expat
  17. * to a DOM representation of the underlying XML file. This is
  18. * a bit overkill, and maybe a later implementation will help to
  19. * cut the work to something simpler, but the current klish
  20. * implementation requires this.
  21. * ------------------------------------------------------
  22. */
  23. #ifdef HAVE_CONFIG_H
  24. #include "config.h"
  25. #endif
  26. #if defined(HAVE_LIB_EXPAT)
  27. #include <string.h>
  28. #include <stdlib.h>
  29. #include <fcntl.h>
  30. #include <sys/stat.h>
  31. #include <unistd.h>
  32. #include <errno.h>
  33. /* FreeBSD have verbatim version of expat named bsdxml */
  34. #ifdef HAVE_LIB_BSDXML
  35. #include <bsdxml.h>
  36. #else
  37. #include <expat.h>
  38. #endif
  39. #include "xmlapi.h"
  40. /** DOM_like XML node
  41. *
  42. * @struct clish_xmlnode_s
  43. */
  44. struct clish_xmlnode_s {
  45. char *name;
  46. clish_xmlnode_t *parent; /**< parent node */
  47. clish_xmlnode_t *children; /**< list of children */
  48. clish_xmlnode_t *next; /**< next sibling */
  49. clish_xmlnode_t *attributes; /**< attributes are nodes too */
  50. char *content; /**< !NULL for text and attributes nodes */
  51. clish_xmlnodetype_t type; /**< node type */
  52. int depth; /**< node depth */
  53. clish_xmldoc_t *doc;
  54. };
  55. /** DOM-like XML document
  56. *
  57. * @struct clish_xmldoc_s
  58. */
  59. struct clish_xmldoc_s {
  60. clish_xmlnode_t *root; /**< list of root elements */
  61. clish_xmlnode_t *current; /**< current element */
  62. char *filename; /**< current filename */
  63. };
  64. /*
  65. * Expat need these functions to be able to build a DOM-like tree that
  66. * will be usable by klish.
  67. */
  68. /** Put a element at the and of an element list
  69. *
  70. * @param first first element of the list
  71. * @param node element to add
  72. * @return new first element of the list
  73. */
  74. static clish_xmlnode_t *clish_expat_list_push_back(clish_xmlnode_t *first, clish_xmlnode_t *node)
  75. {
  76. clish_xmlnode_t *cur = first;
  77. clish_xmlnode_t *prev = NULL;
  78. while (cur) {
  79. prev = cur;
  80. cur = cur->next;
  81. }
  82. if (prev) {
  83. prev->next = node;
  84. return first;
  85. }
  86. return node;
  87. }
  88. /** Generic add_attr() function
  89. *
  90. * @param first first attribute in the attribute list
  91. * @param n attribute name
  92. * @param v attribute value
  93. * @return the new first attribute in the attribute list
  94. */
  95. static clish_xmlnode_t *clish_expat_add_attr(clish_xmlnode_t *first, const char *n, const char *v)
  96. {
  97. clish_xmlnode_t *node;
  98. node = malloc(sizeof(clish_xmlnode_t));
  99. if (!node)
  100. return first;
  101. node->name = strdup(n);
  102. node->content = strdup(v);
  103. node->children = NULL;
  104. node->attributes = NULL;
  105. node->next = NULL;
  106. node->type = CLISH_XMLNODE_ATTR;
  107. node->depth = 0;
  108. return clish_expat_list_push_back(first, node);
  109. }
  110. /** Run through an expat attribute list, and create a DOM-like attribute list
  111. *
  112. * @param node parent node
  113. * @param attr NULL-terminated attribute liste
  114. *
  115. * Each attribute uses two slots in the expat attribute list. The first one is
  116. * used to store the name, the second one is used to store the value.
  117. */
  118. static void clish_expat_add_attrlist(clish_xmlnode_t *node, const char **attr)
  119. {
  120. int i;
  121. for (i = 0; attr[i]; i += 2) {
  122. node->attributes = clish_expat_add_attr(node->attributes,
  123. attr[i], attr[i+1]);
  124. }
  125. }
  126. /** Generic make_node() function
  127. *
  128. * @param parent XML parent node
  129. * @param type XML node type
  130. * @param n node name (can be NULL, strdup'ed)
  131. * @param v node content (can be NULL, strdup'ed)
  132. * @param attr attribute list
  133. * @return a new node or NULL on error
  134. */
  135. static clish_xmlnode_t *clish_expat_make_node(clish_xmlnode_t *parent,
  136. clish_xmlnodetype_t type,
  137. const char *n,
  138. const char *v,
  139. const char **attr)
  140. {
  141. clish_xmlnode_t *node;
  142. node = malloc(sizeof(clish_xmlnode_t));
  143. if (!node)
  144. return NULL;
  145. node->name = n ? strdup(n) : NULL;
  146. node->content = v ? strdup(v) : NULL;
  147. node->children = NULL;
  148. node->attributes = NULL;
  149. node->next = NULL;
  150. node->parent = parent;
  151. node->doc = parent ? parent->doc : NULL;
  152. node->depth = parent ? parent->depth + 1 : 0;
  153. node->type = type;
  154. if (attr)
  155. clish_expat_add_attrlist(node, attr);
  156. if (parent)
  157. parent->children = clish_expat_list_push_back(parent->children, node);
  158. return node;
  159. }
  160. /** Add a new XML root
  161. *
  162. * @param doc XML document
  163. * @param el root node name
  164. * @param attr expat attribute list
  165. * @return a new root element
  166. */
  167. static clish_xmlnode_t *clish_expat_add_root(clish_xmldoc_t *doc, const char *el, const char **attr)
  168. {
  169. clish_xmlnode_t *node;
  170. node = clish_expat_make_node(NULL, CLISH_XMLNODE_ELM, el, NULL, attr);
  171. if (!node)
  172. return doc->root;
  173. doc->root = clish_expat_list_push_back(doc->root, node);
  174. return node;
  175. }
  176. /** Add a new XML element as a child
  177. *
  178. * @param cur parent XML element
  179. * @param el element name
  180. * @param attr expat attribute list
  181. * @return a new XMl element
  182. */
  183. static clish_xmlnode_t *clish_expat_add_child(clish_xmlnode_t *cur, const char *el, const char **attr)
  184. {
  185. clish_xmlnode_t *node;
  186. node = clish_expat_make_node(cur, CLISH_XMLNODE_ELM, el, NULL, attr);
  187. if (!node)
  188. return cur;
  189. return node;
  190. }
  191. /** Expat handler: element content
  192. *
  193. * @param data user data
  194. * @param s content (not nul-termainated)
  195. * @param len content length
  196. */
  197. static void clish_expat_chardata_handler(void *data, const char *s, int len)
  198. {
  199. clish_xmldoc_t *doc = data;
  200. if (doc->current) {
  201. char *content = malloc(len + 1);
  202. strncpy(content, s, len);
  203. content[len] = '\0';
  204. clish_expat_make_node(doc->current, CLISH_XMLNODE_TEXT, NULL, content, NULL);
  205. /*
  206. * the previous call is a bit too generic, and strdup() content
  207. * so we need to free out own version of content.
  208. */
  209. free(content);
  210. }
  211. }
  212. /** Expat handler: start XML element
  213. *
  214. * @param data user data
  215. * @param el element name (nul-terminated)
  216. * @param attr expat attribute list
  217. */
  218. static void clish_expat_element_start(void *data, const char *el, const char **attr)
  219. {
  220. clish_xmldoc_t *doc = data;
  221. if (!doc->current) {
  222. doc->current = clish_expat_add_root(doc, el, attr);
  223. } else {
  224. doc->current = clish_expat_add_child(doc->current, el, attr);
  225. }
  226. }
  227. /** Expat handler: end XML element
  228. *
  229. * @param data user data
  230. * @param el element name
  231. */
  232. static void clish_expat_element_end(void *data, const char *el)
  233. {
  234. clish_xmldoc_t *doc = data;
  235. if (doc->current) {
  236. doc->current = doc->current->parent;
  237. }
  238. }
  239. /** Free a node, its children and its attributes
  240. *
  241. * @param node node to free
  242. */
  243. static void clish_expat_free_node(clish_xmlnode_t *cur)
  244. {
  245. clish_xmlnode_t *node;
  246. clish_xmlnode_t *first;
  247. if (cur->attributes) {
  248. first = cur->attributes;
  249. while (first) {
  250. node = first;
  251. first = first->next;
  252. clish_expat_free_node(node);
  253. }
  254. }
  255. if (cur->children) {
  256. first = cur->children;
  257. while (first) {
  258. node = first;
  259. first = first->next;
  260. clish_expat_free_node(node);
  261. }
  262. }
  263. if (cur->name)
  264. free(cur->name);
  265. if (cur->content)
  266. free(cur->content);
  267. free(cur);
  268. }
  269. /*
  270. * Public interface
  271. */
  272. clish_xmldoc_t *clish_xmldoc_read(const char *filename)
  273. {
  274. clish_xmldoc_t *doc;
  275. struct stat sb;
  276. int fd;
  277. char *buffer;
  278. XML_Parser parser;
  279. int rb;
  280. doc = malloc(sizeof(clish_xmldoc_t));
  281. if (!doc)
  282. return NULL;
  283. memset(doc, 0, sizeof(clish_xmldoc_t));
  284. doc->filename = strdup(filename);
  285. parser = XML_ParserCreate(NULL);
  286. if (!parser)
  287. goto error_parser_create;
  288. XML_SetUserData(parser, doc);
  289. XML_SetCharacterDataHandler(parser, clish_expat_chardata_handler);
  290. XML_SetElementHandler(parser,
  291. clish_expat_element_start,
  292. clish_expat_element_end);
  293. fd = open(filename, O_RDONLY);
  294. if (fd < 0)
  295. goto error_open;
  296. fstat(fd, &sb);
  297. buffer = malloc(sb.st_size+1);
  298. rb = read(fd, buffer, sb.st_size);
  299. if (rb < 0) {
  300. close(fd);
  301. goto error_parse;
  302. }
  303. buffer[sb.st_size] = 0;
  304. close(fd);
  305. if (!XML_Parse(parser, buffer, sb.st_size, 1))
  306. goto error_parse;
  307. XML_ParserFree(parser);
  308. free(buffer);
  309. return doc;
  310. error_parse:
  311. free(buffer);
  312. error_open:
  313. XML_ParserFree(parser);
  314. error_parser_create:
  315. clish_xmldoc_release(doc);
  316. return NULL;
  317. }
  318. void clish_xmldoc_release(clish_xmldoc_t *doc)
  319. {
  320. if (doc) {
  321. clish_xmlnode_t *node;
  322. while (doc->root) {
  323. node = doc->root;
  324. doc->root = node->next;
  325. clish_expat_free_node(node);
  326. }
  327. if (doc->filename)
  328. free(doc->filename);
  329. free(doc);
  330. }
  331. }
  332. int clish_xmldoc_is_valid(clish_xmldoc_t *doc)
  333. {
  334. return doc && doc->root;
  335. }
  336. int clish_xmldoc_error_caps(clish_xmldoc_t *doc)
  337. {
  338. return CLISH_XMLERR_NOCAPS;
  339. }
  340. int clish_xmldoc_get_err_line(clish_xmldoc_t *doc)
  341. {
  342. return -1;
  343. }
  344. int clish_xmldoc_get_err_col(clish_xmldoc_t *doc)
  345. {
  346. return -1;
  347. }
  348. const char *clish_xmldoc_get_err_msg(clish_xmldoc_t *doc)
  349. {
  350. return "";
  351. }
  352. int clish_xmlnode_get_type(clish_xmlnode_t *node)
  353. {
  354. if (node)
  355. return node->type;
  356. return CLISH_XMLNODE_UNKNOWN;
  357. }
  358. clish_xmlnode_t *clish_xmldoc_get_root(clish_xmldoc_t *doc)
  359. {
  360. if (doc)
  361. return doc->root;
  362. return NULL;
  363. }
  364. clish_xmlnode_t *clish_xmlnode_parent(clish_xmlnode_t *node)
  365. {
  366. if (node)
  367. return node->parent;
  368. return NULL;
  369. }
  370. clish_xmlnode_t *clish_xmlnode_next_child(clish_xmlnode_t *parent,
  371. clish_xmlnode_t *curchild)
  372. {
  373. if (curchild)
  374. return curchild->next;
  375. if (parent)
  376. return parent->children;
  377. return NULL;
  378. }
  379. char *clish_xmlnode_fetch_attr(clish_xmlnode_t *node,
  380. const char *attrname)
  381. {
  382. if (node) {
  383. clish_xmlnode_t *n = node->attributes;
  384. while (n) {
  385. if (strcmp(n->name, attrname) == 0)
  386. return n->content;
  387. n = n->next;
  388. }
  389. }
  390. return NULL;
  391. }
  392. int clish_xmlnode_get_content(clish_xmlnode_t *node, char *content,
  393. unsigned int *contentlen)
  394. {
  395. int minlen = 1;
  396. if (node && content && contentlen) {
  397. clish_xmlnode_t *children = node->children;
  398. while (children) {
  399. if (children->type == CLISH_XMLNODE_TEXT && children->content)
  400. minlen += strlen(children->content);
  401. children = children->next;
  402. }
  403. if (minlen >= *contentlen) {
  404. *contentlen = minlen + 1;
  405. return -E2BIG;
  406. }
  407. children = node->children;
  408. *content = 0;
  409. while (children) {
  410. if (children->type == CLISH_XMLNODE_TEXT && children->content)
  411. strcat(content, children->content);
  412. children = children->next;
  413. }
  414. return 0;
  415. }
  416. return -EINVAL;
  417. }
  418. int clish_xmlnode_get_name(clish_xmlnode_t *node, char *name,
  419. unsigned int *namelen)
  420. {
  421. if (node && name && namelen) {
  422. if (strlen(node->name) >= *namelen) {
  423. *namelen = strlen(node->name) + 1;
  424. return -E2BIG;
  425. }
  426. sprintf(name, "%s", node->name);
  427. return 0;
  428. }
  429. return -EINVAL;
  430. }
  431. void clish_xmlnode_print(clish_xmlnode_t *node, FILE *out)
  432. {
  433. if (node) {
  434. int i;
  435. clish_xmlnode_t *a;
  436. for (i=0; i<node->depth; ++i) {
  437. fprintf(out, " ");
  438. }
  439. fprintf(out, "<%s", node->name);
  440. a = node->attributes;
  441. while (a) {
  442. fprintf(out, " %s='%s'", a->name, a->content);
  443. a = a->next;
  444. }
  445. fprintf(out, ">...");
  446. }
  447. }
  448. void clish_xml_release(void *p)
  449. {
  450. /* nothing to release */
  451. }
  452. #endif /* HAVE_LIB_EXPAT */