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