setexpr.c 7.8 KB

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  1. // SPDX-License-Identifier: GPL-2.0+
  2. /*
  3. * Copyright 2008 Freescale Semiconductor, Inc.
  4. * Copyright 2013 Wolfgang Denk <wd@denx.de>
  5. */
  6. /*
  7. * This file provides a shell like 'expr' function to return.
  8. */
  9. #include <common.h>
  10. #include <config.h>
  11. #include <command.h>
  12. #include <env.h>
  13. #include <log.h>
  14. #include <mapmem.h>
  15. static ulong get_arg(char *s, int w)
  16. {
  17. /*
  18. * If the parameter starts with a '*' then assume it is a pointer to
  19. * the value we want.
  20. */
  21. if (s[0] == '*') {
  22. ulong *p;
  23. ulong addr;
  24. ulong val;
  25. addr = simple_strtoul(&s[1], NULL, 16);
  26. switch (w) {
  27. case 1:
  28. p = map_sysmem(addr, sizeof(uchar));
  29. val = (ulong)*(uchar *)p;
  30. unmap_sysmem(p);
  31. return val;
  32. case 2:
  33. p = map_sysmem(addr, sizeof(ushort));
  34. val = (ulong)*(ushort *)p;
  35. unmap_sysmem(p);
  36. return val;
  37. case 4:
  38. default:
  39. p = map_sysmem(addr, sizeof(ulong));
  40. val = *p;
  41. unmap_sysmem(p);
  42. return val;
  43. }
  44. } else {
  45. return simple_strtoul(s, NULL, 16);
  46. }
  47. }
  48. #ifdef CONFIG_REGEX
  49. #include <slre.h>
  50. #define SLRE_BUFSZ 16384
  51. #define SLRE_PATSZ 4096
  52. /*
  53. * memstr - Find the first substring in memory
  54. * @s1: The string to be searched
  55. * @s2: The string to search for
  56. *
  57. * Similar to and based on strstr(),
  58. * but strings do not need to be NUL terminated.
  59. */
  60. static char *memstr(const char *s1, int l1, const char *s2, int l2)
  61. {
  62. if (!l2)
  63. return (char *)s1;
  64. while (l1 >= l2) {
  65. l1--;
  66. if (!memcmp(s1, s2, l2))
  67. return (char *)s1;
  68. s1++;
  69. }
  70. return NULL;
  71. }
  72. static char *substitute(char *string, /* string buffer */
  73. int *slen, /* current string length */
  74. int ssize, /* string bufer size */
  75. const char *old,/* old (replaced) string */
  76. int olen, /* length of old string */
  77. const char *new,/* new (replacement) string */
  78. int nlen) /* length of new string */
  79. {
  80. char *p = memstr(string, *slen, old, olen);
  81. if (p == NULL)
  82. return NULL;
  83. debug("## Match at pos %ld: match len %d, subst len %d\n",
  84. (long)(p - string), olen, nlen);
  85. /* make sure replacement matches */
  86. if (*slen + nlen - olen > ssize) {
  87. printf("## error: substitution buffer overflow\n");
  88. return NULL;
  89. }
  90. /* move tail if needed */
  91. if (olen != nlen) {
  92. int tail, len;
  93. len = (olen > nlen) ? olen : nlen;
  94. tail = ssize - (p + len - string);
  95. debug("## tail len %d\n", tail);
  96. memmove(p + nlen, p + olen, tail);
  97. }
  98. /* insert substitue */
  99. memcpy(p, new, nlen);
  100. *slen += nlen - olen;
  101. return p + nlen;
  102. }
  103. /*
  104. * Perform regex operations on a environment variable
  105. *
  106. * Returns 0 if OK, 1 in case of errors.
  107. */
  108. static int regex_sub(const char *name,
  109. const char *r, const char *s, const char *t,
  110. int global)
  111. {
  112. struct slre slre;
  113. char data[SLRE_BUFSZ];
  114. char *datap = data;
  115. const char *value;
  116. int res, len, nlen, loop;
  117. if (name == NULL)
  118. return 1;
  119. if (slre_compile(&slre, r) == 0) {
  120. printf("Error compiling regex: %s\n", slre.err_str);
  121. return 1;
  122. }
  123. if (t == NULL) {
  124. value = env_get(name);
  125. if (value == NULL) {
  126. printf("## Error: variable \"%s\" not defined\n", name);
  127. return 1;
  128. }
  129. t = value;
  130. }
  131. debug("REGEX on %s=%s\n", name, t);
  132. debug("REGEX=\"%s\", SUBST=\"%s\", GLOBAL=%d\n",
  133. r, s ? s : "<NULL>", global);
  134. len = strlen(t);
  135. if (len + 1 > SLRE_BUFSZ) {
  136. printf("## error: subst buffer overflow: have %d, need %d\n",
  137. SLRE_BUFSZ, len + 1);
  138. return 1;
  139. }
  140. strcpy(data, t);
  141. if (s == NULL)
  142. nlen = 0;
  143. else
  144. nlen = strlen(s);
  145. for (loop = 0;; loop++) {
  146. struct cap caps[slre.num_caps + 2];
  147. char nbuf[SLRE_PATSZ];
  148. const char *old;
  149. char *np;
  150. int i, olen;
  151. (void) memset(caps, 0, sizeof(caps));
  152. res = slre_match(&slre, datap, len, caps);
  153. debug("Result: %d\n", res);
  154. for (i = 0; i < slre.num_caps; i++) {
  155. if (caps[i].len > 0) {
  156. debug("Substring %d: [%.*s]\n", i,
  157. caps[i].len, caps[i].ptr);
  158. }
  159. }
  160. if (res == 0) {
  161. if (loop == 0) {
  162. printf("%s: No match\n", t);
  163. return 1;
  164. } else {
  165. break;
  166. }
  167. }
  168. debug("## MATCH ## %s\n", data);
  169. if (s == NULL) {
  170. printf("%s=%s\n", name, t);
  171. return 1;
  172. }
  173. old = caps[0].ptr;
  174. olen = caps[0].len;
  175. if (nlen + 1 >= SLRE_PATSZ) {
  176. printf("## error: pattern buffer overflow: have %d, need %d\n",
  177. SLRE_BUFSZ, nlen + 1);
  178. return 1;
  179. }
  180. strcpy(nbuf, s);
  181. debug("## SUBST(1) ## %s\n", nbuf);
  182. /*
  183. * Handle back references
  184. *
  185. * Support for \0 ... \9, where \0 is the
  186. * whole matched pattern (similar to &).
  187. *
  188. * Implementation is a bit simpleminded as
  189. * backrefs are substituted sequentially, one
  190. * by one. This will lead to somewhat
  191. * unexpected results if the replacement
  192. * strings contain any \N strings then then
  193. * may get substitued, too. We accept this
  194. * restriction for the sake of simplicity.
  195. */
  196. for (i = 0; i < 10; ++i) {
  197. char backref[2] = {
  198. '\\',
  199. '0',
  200. };
  201. if (caps[i].len == 0)
  202. break;
  203. backref[1] += i;
  204. debug("## BACKREF %d: replace \"%.*s\" by \"%.*s\" in \"%s\"\n",
  205. i,
  206. 2, backref,
  207. caps[i].len, caps[i].ptr,
  208. nbuf);
  209. for (np = nbuf;;) {
  210. char *p = memstr(np, nlen, backref, 2);
  211. if (p == NULL)
  212. break;
  213. np = substitute(np, &nlen,
  214. SLRE_PATSZ,
  215. backref, 2,
  216. caps[i].ptr, caps[i].len);
  217. if (np == NULL)
  218. return 1;
  219. }
  220. }
  221. debug("## SUBST(2) ## %s\n", nbuf);
  222. datap = substitute(datap, &len, SLRE_BUFSZ,
  223. old, olen,
  224. nbuf, nlen);
  225. if (datap == NULL)
  226. return 1;
  227. debug("## REMAINDER: %s\n", datap);
  228. debug("## RESULT: %s\n", data);
  229. if (!global)
  230. break;
  231. }
  232. debug("## FINAL (now env_set()) : %s\n", data);
  233. printf("%s=%s\n", name, data);
  234. return env_set(name, data);
  235. }
  236. #endif
  237. static int do_setexpr(struct cmd_tbl *cmdtp, int flag, int argc,
  238. char *const argv[])
  239. {
  240. ulong a, b;
  241. ulong value;
  242. int w;
  243. /*
  244. * We take 3, 5, or 6 arguments:
  245. * 3 : setexpr name value
  246. * 5 : setexpr name val1 op val2
  247. * setexpr name [g]sub r s
  248. * 6 : setexpr name [g]sub r s t
  249. */
  250. /* > 6 already tested by max command args */
  251. if ((argc < 3) || (argc == 4))
  252. return CMD_RET_USAGE;
  253. w = cmd_get_data_size(argv[0], 4);
  254. a = get_arg(argv[2], w);
  255. /* plain assignment: "setexpr name value" */
  256. if (argc == 3) {
  257. env_set_hex(argv[1], a);
  258. return 0;
  259. }
  260. /* 5 or 6 args (6 args only with [g]sub) */
  261. #ifdef CONFIG_REGEX
  262. /*
  263. * rexep handling: "setexpr name [g]sub r s [t]"
  264. * with 5 args, "t" will be NULL
  265. */
  266. if (strcmp(argv[2], "gsub") == 0)
  267. return regex_sub(argv[1], argv[3], argv[4], argv[5], 1);
  268. if (strcmp(argv[2], "sub") == 0)
  269. return regex_sub(argv[1], argv[3], argv[4], argv[5], 0);
  270. #endif
  271. /* standard operators: "setexpr name val1 op val2" */
  272. if (argc != 5)
  273. return CMD_RET_USAGE;
  274. if (strlen(argv[3]) != 1)
  275. return CMD_RET_USAGE;
  276. b = get_arg(argv[4], w);
  277. switch (argv[3][0]) {
  278. case '|':
  279. value = a | b;
  280. break;
  281. case '&':
  282. value = a & b;
  283. break;
  284. case '+':
  285. value = a + b;
  286. break;
  287. case '^':
  288. value = a ^ b;
  289. break;
  290. case '-':
  291. value = a - b;
  292. break;
  293. case '*':
  294. value = a * b;
  295. break;
  296. case '/':
  297. value = a / b;
  298. break;
  299. case '%':
  300. value = a % b;
  301. break;
  302. default:
  303. printf("invalid op\n");
  304. return 1;
  305. }
  306. env_set_hex(argv[1], value);
  307. return 0;
  308. }
  309. U_BOOT_CMD(
  310. setexpr, 6, 0, do_setexpr,
  311. "set environment variable as the result of eval expression",
  312. "[.b, .w, .l] name [*]value1 <op> [*]value2\n"
  313. " - set environment variable 'name' to the result of the evaluated\n"
  314. " expression specified by <op>. <op> can be &, |, ^, +, -, *, /, %\n"
  315. " size argument is only meaningful if value1 and/or value2 are\n"
  316. " memory addresses (*)\n"
  317. "setexpr[.b, .w, .l] name [*]value\n"
  318. " - load a value into a variable"
  319. #ifdef CONFIG_REGEX
  320. "\n"
  321. "setexpr name gsub r s [t]\n"
  322. " - For each substring matching the regular expression <r> in the\n"
  323. " string <t>, substitute the string <s>. The result is\n"
  324. " assigned to <name>. If <t> is not supplied, use the old\n"
  325. " value of <name>\n"
  326. "setexpr name sub r s [t]\n"
  327. " - Just like gsub(), but replace only the first matching substring"
  328. #endif
  329. );