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 <common.h>
  12 #include <config.h>
  13 #include <command.h>
  14 #include <env.h>
  15 #include <log.h>
  16 #include <mapmem.h>
  17
  18 static ulong get_arg(char *s, int w)
  19 {
  20         /*
  21          * If the parameter starts with a '*' then assume it is a pointer to
  22          * the value we want.
  23          */
  24         if (s[0] == '*') {
  25                 ulong *p;
  26                 ulong addr;
  27                 ulong val;
  28
  29                 addr = simple_strtoul(&s[1], NULL, 16);
  30                 switch (w) {
  31                 case 1:
  32                         p = map_sysmem(addr, sizeof(uchar));
  33                         val = (ulong)*(uchar *)p;
  34                         unmap_sysmem(p);
  35                         return val;
  36                 case 2:
  37                         p = map_sysmem(addr, sizeof(ushort));
  38                         val = (ulong)*(ushort *)p;
  39                         unmap_sysmem(p);
  40                         return val;
  41                 case 4:
  42                 default:
  43                         p = map_sysmem(addr, sizeof(ulong));
  44                         val = *p;
  45                         unmap_sysmem(p);
  46                         return val;
  47                 }
  48         } else {
  49                 return simple_strtoul(s, NULL, 16);
  50         }
  51 }
  52
  53 #ifdef CONFIG_REGEX
  54
  55 #include <slre.h>
  56
  57 #define SLRE_BUFSZ      16384
  58 #define SLRE_PATSZ      4096
  59
  60 /*
  61  * memstr - Find the first substring in memory
  62  * @s1: The string to be searched
  63  * @s2: The string to search for
  64  *
  65  * Similar to and based on strstr(),
  66  * but strings do not need to be NUL terminated.
  67  */
  68 static char *memstr(const char *s1, int l1, const char *s2, int l2)
  69 {
  70         if (!l2)
  71                 return (char *)s1;
  72
  73         while (l1 >= l2) {
  74                 l1--;
  75                 if (!memcmp(s1, s2, l2))
  76                         return (char *)s1;
  77                 s1++;
  78         }
  79         return NULL;
  80 }
  81
  82 static char *substitute(char *string,   /* string buffer */
  83                         int *slen,      /* current string length */
  84                         int ssize,      /* string bufer size */
  85                         const char *old,/* old (replaced) string */
  86                         int olen,       /* length of old string */
  87                         const char *new,/* new (replacement) string */
  88                         int nlen)       /* length of new string */
  89 {
  90         char *p = memstr(string, *slen, old, olen);
  91
  92         if (p == NULL)
  93                 return NULL;
  94
  95         debug("## Match at pos %ld: match len %d, subst len %d\n",
  96                 (long)(p - string), olen, nlen);
  97
  98         /* make sure replacement matches */
  99         if (*slen + nlen - olen > ssize) {
 100                 printf("## error: substitution buffer overflow\n");
 101                 return NULL;
 102         }
 103
 104         /* move tail if needed */
 105         if (olen != nlen) {
 106                 int tail, len;
 107
 108                 len = (olen > nlen) ? olen : nlen;
 109
 110                 tail = ssize - (p + len - string);
 111
 112                 debug("## tail len %d\n", tail);
 113
 114                 memmove(p + nlen, p + olen, tail);
 115         }
 116
 117         /* insert substitue */
 118         memcpy(p, new, nlen);
 119
 120         *slen += nlen - olen;
 121
 122         return p + nlen;
 123 }
 124
 125 /*
 126  * Perform regex operations on a environment variable
 127  *
 128  * Returns 0 if OK, 1 in case of errors.
 129  */
 130 static int regex_sub(const char *name,
 131         const char *r, const char *s, const char *t,
 132         int global)
 133 {
 134         struct slre slre;
 135         char data[SLRE_BUFSZ];
 136         char *datap = data;
 137         const char *value;
 138         int res, len, nlen, loop;
 139
 140         if (name == NULL)
 141                 return 1;
 142
 143         if (slre_compile(&slre, r) == 0) {
 144                 printf("Error compiling regex: %s\n", slre.err_str);
 145                 return 1;
 146         }
 147
 148         if (t == NULL) {
 149                 value = env_get(name);
 150
 151                 if (value == NULL) {
 152                         printf("## Error: variable \"%s\" not defined\n", name);
 153                         return 1;
 154                 }
 155                 t = value;
 156         }
 157
 158         debug("REGEX on %s=%s\n", name, t);
 159         debug("REGEX=\"%s\", SUBST=\"%s\", GLOBAL=%d\n",
 160                 r, s ? s : "<NULL>", global);
 161
 162         len = strlen(t);
 163         if (len + 1 > SLRE_BUFSZ) {
 164                 printf("## error: subst buffer overflow: have %d, need %d\n",
 165                         SLRE_BUFSZ, len + 1);
 166                 return 1;
 167         }
 168
 169         strcpy(data, t);
 170
 171         if (s == NULL)
 172                 nlen = 0;
 173         else
 174                 nlen = strlen(s);
 175
 176         for (loop = 0;; loop++) {
 177                 struct cap caps[slre.num_caps + 2];
 178                 char nbuf[SLRE_PATSZ];
 179                 const char *old;
 180                 char *np;
 181                 int i, olen;
 182
 183                 (void) memset(caps, 0, sizeof(caps));
 184
 185                 res = slre_match(&slre, datap, len, caps);
 186
 187                 debug("Result: %d\n", res);
 188
 189                 for (i = 0; i < slre.num_caps; i++) {
 190                         if (caps[i].len > 0) {
 191                                 debug("Substring %d: [%.*s]\n", i,
 192                                         caps[i].len, caps[i].ptr);
 193                         }
 194                 }
 195
 196                 if (res == 0) {
 197                         if (loop == 0) {
 198                                 printf("%s: No match\n", t);
 199                                 return 1;
 200                         } else {
 201                                 break;
 202                         }
 203                 }
 204
 205                 debug("## MATCH ## %s\n", data);
 206
 207                 if (s == NULL) {
 208                         printf("%s=%s\n", name, t);
 209                         return 1;
 210                 }
 211
 212                 old = caps[0].ptr;
 213                 olen = caps[0].len;
 214
 215                 if (nlen + 1 >= SLRE_PATSZ) {
 216                         printf("## error: pattern buffer overflow: have %d, need %d\n",
 217                                 SLRE_BUFSZ, nlen + 1);
 218                         return 1;
 219                 }
 220                 strcpy(nbuf, s);
 221
 222                 debug("## SUBST(1) ## %s\n", nbuf);
 223
 224                 /*
 225                  * Handle back references
 226                  *
 227                  * Support for \0 ... \9, where \0 is the
 228                  * whole matched pattern (similar to &).
 229                  *
 230                  * Implementation is a bit simpleminded as
 231                  * backrefs are substituted sequentially, one
 232                  * by one.  This will lead to somewhat
 233                  * unexpected results if the replacement
 234                  * strings contain any \N strings then then
 235                  * may get substitued, too.  We accept this
 236                  * restriction for the sake of simplicity.
 237                  */
 238                 for (i = 0; i < 10; ++i) {
 239                         char backref[2] = {
 240                                 '\\',
 241                                 '0',
 242                         };
 243
 244                         if (caps[i].len == 0)
 245                                 break;
 246
 247                         backref[1] += i;
 248
 249                         debug("## BACKREF %d: replace \"%.*s\" by \"%.*s\" in \"%s\"\n",
 250                                 i,
 251                                 2, backref,
 252                                 caps[i].len, caps[i].ptr,
 253                                 nbuf);
 254
 255                         for (np = nbuf;;) {
 256                                 char *p = memstr(np, nlen, backref, 2);
 257
 258                                 if (p == NULL)
 259                                         break;
 260
 261                                 np = substitute(np, &nlen,
 262                                         SLRE_PATSZ,
 263                                         backref, 2,
 264                                         caps[i].ptr, caps[i].len);
 265
 266                                 if (np == NULL)
 267                                         return 1;
 268                         }
 269                 }
 270                 debug("## SUBST(2) ## %s\n", nbuf);
 271
 272                 datap = substitute(datap, &len, SLRE_BUFSZ,
 273                                 old, olen,
 274                                 nbuf, nlen);
 275
 276                 if (datap == NULL)
 277                         return 1;
 278
 279                 debug("## REMAINDER: %s\n", datap);
 280
 281                 debug("## RESULT: %s\n", data);
 282
 283                 if (!global)
 284                         break;
 285         }
 286         debug("## FINAL (now env_set()) :  %s\n", data);
 287
 288         printf("%s=%s\n", name, data);
 289
 290         return env_set(name, data);
 291 }
 292 #endif
 293
 294 static int do_setexpr(struct cmd_tbl *cmdtp, int flag, int argc,
 295                       char *const argv[])
 296 {
 297         ulong a, b;
 298         ulong value;
 299         int w;
 300
 301         /*
 302          * We take 3, 5, or 6 arguments:
 303          * 3 : setexpr name value
 304          * 5 : setexpr name val1 op val2
 305          *     setexpr name [g]sub r s
 306          * 6 : setexpr name [g]sub r s t
 307          */
 308
 309         /* > 6 already tested by max command args */
 310         if ((argc < 3) || (argc == 4))
 311                 return CMD_RET_USAGE;
 312
 313         w = cmd_get_data_size(argv[0], 4);
 314
 315         a = get_arg(argv[2], w);
 316
 317         /* plain assignment: "setexpr name value" */
 318         if (argc == 3) {
 319                 env_set_hex(argv[1], a);
 320                 return 0;
 321         }
 322
 323         /* 5 or 6 args (6 args only with [g]sub) */
 324 #ifdef CONFIG_REGEX
 325         /*
 326          * rexep handling: "setexpr name [g]sub r s [t]"
 327          * with 5 args, "t" will be NULL
 328          */
 329         if (strcmp(argv[2], "gsub") == 0)
 330                 return regex_sub(argv[1], argv[3], argv[4], argv[5], 1);
 331
 332         if (strcmp(argv[2], "sub") == 0)
 333                 return regex_sub(argv[1], argv[3], argv[4], argv[5], 0);
 334 #endif
 335
 336         /* standard operators: "setexpr name val1 op val2" */
 337         if (argc != 5)
 338                 return CMD_RET_USAGE;
 339
 340         if (strlen(argv[3]) != 1)
 341                 return CMD_RET_USAGE;
 342
 343         b = get_arg(argv[4], w);
 344
 345         switch (argv[3][0]) {
 346         case '|':
 347                 value = a | b;
 348                 break;
 349         case '&':
 350                 value = a & b;
 351                 break;
 352         case '+':
 353                 value = a + b;
 354                 break;
 355         case '^':
 356                 value = a ^ b;
 357                 break;
 358         case '-':
 359                 value = a - b;
 360                 break;
 361         case '*':
 362                 value = a * b;
 363                 break;
 364         case '/':
 365                 value = a / b;
 366                 break;
 367         case '%':
 368                 value = a % b;
 369                 break;
 370         default:
 371                 printf("invalid op\n");
 372                 return 1;
 373         }
 374
 375         env_set_hex(argv[1], value);
 376
 377         return 0;
 378 }
 379
 380 U_BOOT_CMD(
 381         setexpr, 6, 0, do_setexpr,
 382         "set environment variable as the result of eval expression",
 383         "[.b, .w, .l] name [*]value1 <op> [*]value2\n"
 384         "    - set environment variable 'name' to the result of the evaluated\n"
 385         "      expression specified by <op>.  <op> can be &, |, ^, +, -, *, /, %\n"
 386         "      size argument is only meaningful if value1 and/or value2 are\n"
 387         "      memory addresses (*)\n"
 388         "setexpr[.b, .w, .l] name [*]value\n"
 389         "    - load a value into a variable"
 390 #ifdef CONFIG_REGEX
 391         "\n"
 392         "setexpr name gsub r s [t]\n"
 393         "    - For each substring matching the regular expression <r> in the\n"
 394         "      string <t>, substitute the string <s>.  The result is\n"
 395         "      assigned to <name>.  If <t> is not supplied, use the old\n"
 396         "      value of <name>\n"
 397         "setexpr name sub r s [t]\n"
 398         "    - Just like gsub(), but replace only the first matching substring"
 399 #endif
 400 );