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