cmd/setexpr.c

   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 /*
   8  * This file provides a shell like 'expr' function to return.
   9  */
  10
  11 #include <config.h>
  12 #include <command.h>
  13 #include <ctype.h>
  14 #include <env.h>
  15 #include <log.h>
  16 #include <malloc.h>
  17 #include <mapmem.h>
  18 #include <vsprintf.h>
  19 #include <linux/errno.h>
  20 #include <linux/sizes.h>
  21 #include "printf.h"
  22
  23 #define MAX_STR_LEN 128
  24
  25 /**
  26  * struct expr_arg: Holds an argument to an expression
  27  *
  28  * @ival: Integer value (if width is not CMD_DATA_SIZE_STR)
  29  * @sval: String value (if width is CMD_DATA_SIZE_STR)
  30  */
  31 struct expr_arg {
  32         union {
  33                 ulong ival;
  34                 char *sval;
  35         };
  36 };
  37
  38 static int get_arg(char *s, int w, struct expr_arg *argp)
  39 {
  40         struct expr_arg arg;
  41
  42         /*
  43          * If the parameter starts with a '*' then assume it is a pointer to
  44          * the value we want.
  45          */
  46         if (s[0] == '*') {
  47                 ulong *p;
  48                 ulong addr;
  49                 ulong val;
  50                 int len;
  51                 char *str;
  52
  53                 addr = hextoul(&s[1], NULL);
  54                 switch (w) {
  55                 case 1:
  56                         p = map_sysmem(addr, sizeof(uchar));
  57                         val = (ulong)*(uchar *)p;
  58                         unmap_sysmem(p);
  59                         arg.ival = val;
  60                         break;
  61                 case 2:
  62                         p = map_sysmem(addr, sizeof(ushort));
  63                         val = (ulong)*(ushort *)p;
  64                         unmap_sysmem(p);
  65                         arg.ival = val;
  66                         break;
  67                 case CMD_DATA_SIZE_STR:
  68                         p = map_sysmem(addr, SZ_64K);
  69
  70                         /* Maximum string length of 64KB plus terminator */
  71                         len = strnlen((char *)p, SZ_64K) + 1;
  72                         str = malloc(len);
  73                         if (!str) {
  74                                 printf("Out of memory\n");
  75                                 return -ENOMEM;
  76                         }
  77                         memcpy(str, p, len);
  78                         str[len - 1] = '\0';
  79                         unmap_sysmem(p);
  80                         arg.sval = str;
  81                         break;
  82                 case 4:
  83                         p = map_sysmem(addr, sizeof(u32));
  84                         val = *(u32 *)p;
  85                         unmap_sysmem(p);
  86                         arg.ival = val;
  87                         break;
  88                 default:
  89                         p = map_sysmem(addr, sizeof(ulong));
  90                         val = *p;
  91                         unmap_sysmem(p);
  92                         arg.ival = val;
  93                         break;
  94                 }
  95         } else {
  96                 if (w == CMD_DATA_SIZE_STR)
  97                         return -EINVAL;
  98                 arg.ival = hextoul(s, NULL);
  99         }
 100         *argp = arg;
 101
 102         return 0;
 103 }
 104
 105 #ifdef CONFIG_REGEX
 106
 107 #include <slre.h>
 108
 109 /*
 110  * memstr - Find the first substring in memory
 111  * @s1: The string to be searched
 112  * @s2: The string to search for
 113  *
 114  * Similar to and based on strstr(),
 115  * but strings do not need to be NUL terminated.
 116  */
 117 static char *memstr(const char *s1, int l1, const char *s2, int l2)
 118 {
 119         if (!l2)
 120                 return (char *)s1;
 121
 122         while (l1 >= l2) {
 123                 l1--;
 124                 if (!memcmp(s1, s2, l2))
 125                         return (char *)s1;
 126                 s1++;
 127         }
 128         return NULL;
 129 }
 130
 131 /**
 132  * substitute() - Substitute part of one string with another
 133  *
 134  * This updates @string so that the first occurrence of @old is replaced with
 135  * @new
 136  *
 137  * @string: String buffer containing string to update at the start
 138  * @slen: Pointer to current string length, updated on success
 139  * @ssize: Size of string buffer
 140  * @old: Old string to find in the buffer (no terminator needed)
 141  * @olen: Length of @old excluding terminator
 142  * @new: New string to replace @old with
 143  * @nlen: Length of @new excluding terminator
 144  * Return: pointer to immediately after the copied @new in @string, or NULL if
 145  *      no replacement took place
 146  */
 147 static char *substitute(char *string, int *slen, int ssize,
 148                         const char *old, int olen, const char *new, int nlen)
 149 {
 150         char *p = memstr(string, *slen, old, olen);
 151
 152         if (p == NULL)
 153                 return NULL;
 154
 155         debug("## Match at pos %ld: match len %d, subst len %d\n",
 156                 (long)(p - string), olen, nlen);
 157
 158         /* make sure replacement matches */
 159         if (*slen + nlen - olen > ssize) {
 160                 printf("## error: substitution buffer overflow\n");
 161                 return NULL;
 162         }
 163
 164         /* move tail if needed */
 165         if (olen != nlen) {
 166                 int tail, len;
 167
 168                 len = (olen > nlen) ? olen : nlen;
 169
 170                 tail = ssize - (p + len - string);
 171
 172                 debug("## tail len %d\n", tail);
 173
 174                 memmove(p + nlen, p + olen, tail);
 175         }
 176
 177         /* insert substitute */
 178         memcpy(p, new, nlen);
 179
 180         *slen += nlen - olen;
 181
 182         return p + nlen;
 183 }
 184
 185 int setexpr_regex_sub(char *data, uint data_size, char *nbuf, uint nbuf_size,
 186                       const char *r, const char *s, bool global)
 187 {
 188         struct slre slre;
 189         char *datap = data;
 190         int res, len, nlen, loop;
 191
 192         if (slre_compile(&slre, r) == 0) {
 193                 printf("Error compiling regex: %s\n", slre.err_str);
 194                 return 1;
 195         }
 196
 197         len = strlen(data);
 198         for (loop = 0;; loop++) {
 199                 struct cap caps[slre.num_caps + 2];
 200                 const char *old;
 201                 char *np;
 202                 int i, olen;
 203
 204                 (void) memset(caps, 0, sizeof(caps));
 205
 206                 res = slre_match(&slre, datap, len - (datap - data), caps);
 207
 208                 debug("Result: %d\n", res);
 209
 210                 for (i = 0; i <= slre.num_caps; i++) {
 211                         if (caps[i].len > 0) {
 212                                 debug("Substring %d: [%.*s]\n", i,
 213                                         caps[i].len, caps[i].ptr);
 214                         }
 215                 }
 216
 217                 if (res == 0) {
 218                         if (loop == 0) {
 219                                 debug("%s: No match\n", data);
 220                         } else {
 221                                 debug("## MATCH ## %s\n", data);
 222                         }
 223                         break;
 224                 }
 225
 226                 if (!s)
 227                         return 1;
 228
 229                 old = caps[0].ptr;
 230                 olen = caps[0].len;
 231                 nlen = strlen(s);
 232
 233                 if (nlen + 1 >= nbuf_size) {
 234                         printf("## error: pattern buffer overflow: have %d, need %d\n",
 235                                nbuf_size, nlen + 1);
 236                         return 1;
 237                 }
 238                 strcpy(nbuf, s);
 239
 240                 debug("## SUBST(1) ## %s\n", nbuf);
 241
 242                 /*
 243                  * Handle back references
 244                  *
 245                  * Support for \0 ... \9, where \0 is the
 246                  * whole matched pattern (similar to &).
 247                  *
 248                  * Implementation is a bit simpleminded as
 249                  * backrefs are substituted sequentially, one
 250                  * by one.  This will lead to somewhat
 251                  * unexpected results if the replacement
 252                  * strings contain any \N strings then then
 253                  * may get substitued, too.  We accept this
 254                  * restriction for the sake of simplicity.
 255                  */
 256                 for (i = 0; i < 10; ++i) {
 257                         char backref[2] = {
 258                                 '\\',
 259                                 '0',
 260                         };
 261
 262                         if (caps[i].len == 0)
 263                                 break;
 264
 265                         backref[1] += i;
 266
 267                         debug("## BACKREF %d: replace \"%.*s\" by \"%.*s\" in \"%s\"\n",
 268                                 i,
 269                                 2, backref,
 270                                 caps[i].len, caps[i].ptr,
 271                                 nbuf);
 272
 273                         for (np = nbuf;;) {
 274                                 char *p = memstr(np, nlen, backref, 2);
 275
 276                                 if (p == NULL)
 277                                         break;
 278
 279                                 np = substitute(np, &nlen,
 280                                         nbuf_size - (np - nbuf),
 281                                         backref, 2,
 282                                         caps[i].ptr, caps[i].len);
 283
 284                                 if (np == NULL)
 285                                         return 1;
 286                         }
 287                 }
 288                 debug("## SUBST(2) ## %s\n", nbuf);
 289
 290                 datap = substitute(datap, &len, data_size - (datap - data),
 291                                    old, olen, nbuf, nlen);
 292
 293                 if (datap == NULL)
 294                         return 1;
 295
 296                 debug("## REMAINDER: %s\n", datap);
 297
 298                 debug("## RESULT: %s\n", data);
 299
 300                 if (!global)
 301                         break;
 302         }
 303         debug("## FINAL (now env_set()) :  %s\n", data);
 304
 305         return 0;
 306 }
 307
 308 #define SLRE_BUFSZ      16384
 309 #define SLRE_PATSZ      4096
 310
 311 /*
 312  * Perform regex operations on a environment variable
 313  *
 314  * Returns 0 if OK, 1 in case of errors.
 315  */
 316 static int regex_sub_var(const char *name, const char *r, const char *s,
 317                          const char *t, int global)
 318 {
 319         struct slre slre;
 320         char data[SLRE_BUFSZ];
 321         char nbuf[SLRE_PATSZ];
 322         const char *value;
 323         int len;
 324         int ret;
 325
 326         if (!name)
 327                 return 1;
 328
 329         if (slre_compile(&slre, r) == 0) {
 330                 printf("Error compiling regex: %s\n", slre.err_str);
 331                 return 1;
 332         }
 333
 334         if (!t) {
 335                 value = env_get(name);
 336                 if (!value) {
 337                         printf("## Error: variable \"%s\" not defined\n", name);
 338                         return 1;
 339                 }
 340                 t = value;
 341         }
 342
 343         debug("REGEX on %s=%s\n", name, t);
 344         debug("REGEX=\"%s\", SUBST=\"%s\", GLOBAL=%d\n", r, s ? s : "<NULL>",
 345               global);
 346
 347         len = strlen(t);
 348         if (len + 1 > SLRE_BUFSZ) {
 349                 printf("## error: subst buffer overflow: have %d, need %d\n",
 350                        SLRE_BUFSZ, len + 1);
 351                 return 1;
 352         }
 353
 354         strcpy(data, t);
 355
 356         ret = setexpr_regex_sub(data, SLRE_BUFSZ, nbuf, SLRE_PATSZ, r, s,
 357                                 global);
 358         if (ret)
 359                 return 1;
 360
 361         debug("%s=%s\n", name, data);
 362
 363         return env_set(name, data);
 364 }
 365 #endif
 366
 367 static int do_setexpr(struct cmd_tbl *cmdtp, int flag, int argc,
 368                       char *const argv[])
 369 {
 370         struct expr_arg aval, bval;
 371         ulong value;
 372         int ret = 0;
 373         int w;
 374
 375         /*
 376          * We take 3, 5, or 6 arguments, except fmt operation, which
 377          * takes 4 to 8 arguments (limited by _maxargs):
 378          * 3 : setexpr name value
 379          * 5 : setexpr name val1 op val2
 380          *     setexpr name [g]sub r s
 381          * 6 : setexpr name [g]sub r s t
 382          *     setexpr name fmt format [val1] [val2] [val3] [val4]
 383          */
 384
 385         if (argc < 3)
 386                 return CMD_RET_USAGE;
 387
 388         w = cmd_get_data_size(argv[0], 4);
 389
 390         if (get_arg(argv[2], w, &aval))
 391                 return CMD_RET_FAILURE;
 392
 393         /* format string assignment: "setexpr name fmt %d value" */
 394         if (strcmp(argv[2], "fmt") == 0 && IS_ENABLED(CONFIG_CMD_SETEXPR_FMT)) {
 395                 char str[MAX_STR_LEN];
 396                 int result;
 397
 398                 if (argc == 3)
 399                         return CMD_RET_USAGE;
 400
 401                 result = printf_setexpr(str, sizeof(str), argc - 3, &argv[3]);
 402                 if (result)
 403                         return result;
 404
 405                 return env_set(argv[1], str);
 406         }
 407
 408         if (argc == 4 || argc > 6)
 409                 return CMD_RET_USAGE;
 410
 411         /* plain assignment: "setexpr name value" */
 412         if (argc == 3) {
 413                 if (w == CMD_DATA_SIZE_STR) {
 414                         ret = env_set(argv[1], aval.sval);
 415                         free(aval.sval);
 416                 } else {
 417                         ret = env_set_hex(argv[1], aval.ival);
 418                 }
 419
 420                 return ret;
 421         }
 422
 423         /* 5 or 6 args (6 args only with [g]sub) */
 424 #ifdef CONFIG_REGEX
 425         /*
 426          * rexep handling: "setexpr name [g]sub r s [t]"
 427          * with 5 args, "t" will be NULL
 428          */
 429         if (strcmp(argv[2], "gsub") == 0)
 430                 return regex_sub_var(argv[1], argv[3], argv[4], argv[5], 1);
 431
 432         if (strcmp(argv[2], "sub") == 0)
 433                 return regex_sub_var(argv[1], argv[3], argv[4], argv[5], 0);
 434 #endif
 435
 436         /* standard operators: "setexpr name val1 op val2" */
 437         if (argc != 5)
 438                 return CMD_RET_USAGE;
 439
 440         if (strlen(argv[3]) != 1)
 441                 return CMD_RET_USAGE;
 442
 443         if (get_arg(argv[4], w, &bval)) {
 444                 if (w == CMD_DATA_SIZE_STR)
 445                         free(aval.sval);
 446                 return CMD_RET_FAILURE;
 447         }
 448
 449         if (w == CMD_DATA_SIZE_STR) {
 450                 int len;
 451                 char *str;
 452
 453                 switch (argv[3][0]) {
 454                 case '+':
 455                         len = strlen(aval.sval) + strlen(bval.sval) + 1;
 456                         str = malloc(len);
 457                         if (!str) {
 458                                 printf("Out of memory\n");
 459                                 ret = CMD_RET_FAILURE;
 460                         } else {
 461                                 /* These were copied out and checked earlier */
 462                                 strcpy(str, aval.sval);
 463                                 strcat(str, bval.sval);
 464                                 ret = env_set(argv[1], str);
 465                                 if (ret)
 466                                         printf("Could not set var\n");
 467                                 free(str);
 468                         }
 469                         break;
 470                 default:
 471                         printf("invalid op\n");
 472                         ret = 1;
 473                 }
 474         } else {
 475                 ulong a = aval.ival;
 476                 ulong b = bval.ival;
 477
 478                 switch (argv[3][0]) {
 479                 case '|':
 480                         value = a | b;
 481                         break;
 482                 case '&':
 483                         value = a & b;
 484                         break;
 485                 case '+':
 486                         value = a + b;
 487                         break;
 488                 case '^':
 489                         value = a ^ b;
 490                         break;
 491                 case '-':
 492                         value = a - b;
 493                         break;
 494                 case '*':
 495                         value = a * b;
 496                         break;
 497                 case '/':
 498                         value = a / b;
 499                         break;
 500                 case '%':
 501                         value = a % b;
 502                         break;
 503                 default:
 504                         printf("invalid op\n");
 505                         return 1;
 506                 }
 507
 508                 env_set_hex(argv[1], value);
 509         }
 510
 511         if (w == CMD_DATA_SIZE_STR) {
 512                 free(aval.sval);
 513                 free(bval.sval);
 514         }
 515
 516         return ret;
 517 }
 518
 519 U_BOOT_CMD(
 520         setexpr, 8, 0, do_setexpr,
 521         "set environment variable as the result of eval expression",
 522         "[.b, .w, .l, .s] name [*]value1 <op> [*]value2\n"
 523         "    - set environment variable 'name' to the result of the evaluated\n"
 524         "      expression specified by <op>.  <op> can be &, |, ^, +, -, *, /, %\n"
 525         "      (for strings only + is supported)\n"
 526         "      size argument is only meaningful if value1 and/or value2 are\n"
 527         "      memory addresses (*)\n"
 528         "setexpr[.b, .w, .l] name [*]value\n"
 529         "    - load a value into a variable"
 530 #ifdef CONFIG_CMD_SETEXPR_FMT
 531         "\n"
 532         "setexpr name fmt <format> [value1] [value2] [value3] [value4]\n"
 533         "    - set environment variable 'name' to the result of the bash like\n"
 534         "      format string evaluation of value."
 535 #endif
 536 #ifdef CONFIG_REGEX
 537         "\n"
 538         "setexpr name gsub r s [t]\n"
 539         "    - For each substring matching the regular expression <r> in the\n"
 540         "      string <t>, substitute the string <s>.  The result is\n"
 541         "      assigned to <name>.  If <t> is not supplied, use the old\n"
 542         "      value of <name>. If no substring matching <r> is found in <t>,\n"
 543         "      assign <t> to <name>.\n"
 544         "setexpr name sub r s [t]\n"
 545         "    - Just like gsub(), but replace only the first matching substring"
 546 #endif
 547 );