cmd_setexpr.c 7.5 KB

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