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 <ctype.h>
15 #include <env.h>
16 #include <log.h>
17 #include <malloc.h>
18 #include <mapmem.h>
19 #include <linux/sizes.h>
20 #include "printf.h"
21
22 #define MAX_STR_LEN 128
23
24 /**
25 * struct expr_arg: Holds an argument to an expression
26 *
27 * @ival: Integer value (if width is not CMD_DATA_SIZE_STR)
28 * @sval: String value (if width is CMD_DATA_SIZE_STR)
29 */
30 struct expr_arg {
31 union {
32 ulong ival;
33 char *sval;
34 };
35 };
36
get_arg(char * s,int w,struct expr_arg * argp)37 static int get_arg(char *s, int w, struct expr_arg *argp)
38 {
39 struct expr_arg arg;
40
41 /*
42 * If the parameter starts with a '*' then assume it is a pointer to
43 * the value we want.
44 */
45 if (s[0] == '*') {
46 ulong *p;
47 ulong addr;
48 ulong val;
49 int len;
50 char *str;
51
52 addr = hextoul(&s[1], NULL);
53 switch (w) {
54 case 1:
55 p = map_sysmem(addr, sizeof(uchar));
56 val = (ulong)*(uchar *)p;
57 unmap_sysmem(p);
58 arg.ival = val;
59 break;
60 case 2:
61 p = map_sysmem(addr, sizeof(ushort));
62 val = (ulong)*(ushort *)p;
63 unmap_sysmem(p);
64 arg.ival = val;
65 break;
66 case CMD_DATA_SIZE_STR:
67 p = map_sysmem(addr, SZ_64K);
68
69 /* Maximum string length of 64KB plus terminator */
70 len = strnlen((char *)p, SZ_64K) + 1;
71 str = malloc(len);
72 if (!str) {
73 printf("Out of memory\n");
74 return -ENOMEM;
75 }
76 memcpy(str, p, len);
77 str[len - 1] = '\0';
78 unmap_sysmem(p);
79 arg.sval = str;
80 break;
81 case 4:
82 p = map_sysmem(addr, sizeof(u32));
83 val = *(u32 *)p;
84 unmap_sysmem(p);
85 arg.ival = val;
86 break;
87 default:
88 p = map_sysmem(addr, sizeof(ulong));
89 val = *p;
90 unmap_sysmem(p);
91 arg.ival = val;
92 break;
93 }
94 } else {
95 if (w == CMD_DATA_SIZE_STR)
96 return -EINVAL;
97 arg.ival = hextoul(s, NULL);
98 }
99 *argp = arg;
100
101 return 0;
102 }
103
104 #ifdef CONFIG_REGEX
105
106 #include <slre.h>
107
108 /*
109 * memstr - Find the first substring in memory
110 * @s1: The string to be searched
111 * @s2: The string to search for
112 *
113 * Similar to and based on strstr(),
114 * but strings do not need to be NUL terminated.
115 */
memstr(const char * s1,int l1,const char * s2,int l2)116 static char *memstr(const char *s1, int l1, const char *s2, int l2)
117 {
118 if (!l2)
119 return (char *)s1;
120
121 while (l1 >= l2) {
122 l1--;
123 if (!memcmp(s1, s2, l2))
124 return (char *)s1;
125 s1++;
126 }
127 return NULL;
128 }
129
130 /**
131 * substitute() - Substitute part of one string with another
132 *
133 * This updates @string so that the first occurrence of @old is replaced with
134 * @new
135 *
136 * @string: String buffer containing string to update at the start
137 * @slen: Pointer to current string length, updated on success
138 * @ssize: Size of string buffer
139 * @old: Old string to find in the buffer (no terminator needed)
140 * @olen: Length of @old excluding terminator
141 * @new: New string to replace @old with
142 * @nlen: Length of @new excluding terminator
143 * @return pointer to immediately after the copied @new in @string, or NULL if
144 * no replacement took place
145 */
substitute(char * string,int * slen,int ssize,const char * old,int olen,const char * new,int nlen)146 static char *substitute(char *string, int *slen, int ssize,
147 const char *old, int olen, const char *new, int nlen)
148 {
149 char *p = memstr(string, *slen, old, olen);
150
151 if (p == NULL)
152 return NULL;
153
154 debug("## Match at pos %ld: match len %d, subst len %d\n",
155 (long)(p - string), olen, nlen);
156
157 /* make sure replacement matches */
158 if (*slen + nlen - olen > ssize) {
159 printf("## error: substitution buffer overflow\n");
160 return NULL;
161 }
162
163 /* move tail if needed */
164 if (olen != nlen) {
165 int tail, len;
166
167 len = (olen > nlen) ? olen : nlen;
168
169 tail = ssize - (p + len - string);
170
171 debug("## tail len %d\n", tail);
172
173 memmove(p + nlen, p + olen, tail);
174 }
175
176 /* insert substitute */
177 memcpy(p, new, nlen);
178
179 *slen += nlen - olen;
180
181 return p + nlen;
182 }
183
setexpr_regex_sub(char * data,uint data_size,char * nbuf,uint nbuf_size,const char * r,const char * s,bool global)184 int setexpr_regex_sub(char *data, uint data_size, char *nbuf, uint nbuf_size,
185 const char *r, const char *s, bool global)
186 {
187 struct slre slre;
188 char *datap = data;
189 int res, len, nlen, loop;
190
191 if (slre_compile(&slre, r) == 0) {
192 printf("Error compiling regex: %s\n", slre.err_str);
193 return 1;
194 }
195
196 len = strlen(data);
197 for (loop = 0;; loop++) {
198 struct cap caps[slre.num_caps + 2];
199 const char *old;
200 char *np;
201 int i, olen;
202
203 (void) memset(caps, 0, sizeof(caps));
204
205 res = slre_match(&slre, datap, len - (datap - data), caps);
206
207 debug("Result: %d\n", res);
208
209 for (i = 0; i <= slre.num_caps; i++) {
210 if (caps[i].len > 0) {
211 debug("Substring %d: [%.*s]\n", i,
212 caps[i].len, caps[i].ptr);
213 }
214 }
215
216 if (res == 0) {
217 if (loop == 0) {
218 printf("%s: No match\n", data);
219 return 1;
220 } else {
221 break;
222 }
223 }
224
225 debug("## MATCH ## %s\n", data);
226
227 if (!s)
228 return 1;
229
230 old = caps[0].ptr;
231 olen = caps[0].len;
232 nlen = strlen(s);
233
234 if (nlen + 1 >= nbuf_size) {
235 printf("## error: pattern buffer overflow: have %d, need %d\n",
236 nbuf_size, nlen + 1);
237 return 1;
238 }
239 strcpy(nbuf, s);
240
241 debug("## SUBST(1) ## %s\n", nbuf);
242
243 /*
244 * Handle back references
245 *
246 * Support for \0 ... \9, where \0 is the
247 * whole matched pattern (similar to &).
248 *
249 * Implementation is a bit simpleminded as
250 * backrefs are substituted sequentially, one
251 * by one. This will lead to somewhat
252 * unexpected results if the replacement
253 * strings contain any \N strings then then
254 * may get substitued, too. We accept this
255 * restriction for the sake of simplicity.
256 */
257 for (i = 0; i < 10; ++i) {
258 char backref[2] = {
259 '\\',
260 '0',
261 };
262
263 if (caps[i].len == 0)
264 break;
265
266 backref[1] += i;
267
268 debug("## BACKREF %d: replace \"%.*s\" by \"%.*s\" in \"%s\"\n",
269 i,
270 2, backref,
271 caps[i].len, caps[i].ptr,
272 nbuf);
273
274 for (np = nbuf;;) {
275 char *p = memstr(np, nlen, backref, 2);
276
277 if (p == NULL)
278 break;
279
280 np = substitute(np, &nlen,
281 nbuf_size - (np - nbuf),
282 backref, 2,
283 caps[i].ptr, caps[i].len);
284
285 if (np == NULL)
286 return 1;
287 }
288 }
289 debug("## SUBST(2) ## %s\n", nbuf);
290
291 datap = substitute(datap, &len, data_size - (datap - data),
292 old, olen, nbuf, nlen);
293
294 if (datap == NULL)
295 return 1;
296
297 debug("## REMAINDER: %s\n", datap);
298
299 debug("## RESULT: %s\n", data);
300
301 if (!global)
302 break;
303 }
304 debug("## FINAL (now env_set()) : %s\n", data);
305
306 return 0;
307 }
308
309 #define SLRE_BUFSZ 16384
310 #define SLRE_PATSZ 4096
311
312 /*
313 * Perform regex operations on a environment variable
314 *
315 * Returns 0 if OK, 1 in case of errors.
316 */
regex_sub_var(const char * name,const char * r,const char * s,const char * t,int global)317 static int regex_sub_var(const char *name, const char *r, const char *s,
318 const char *t, int global)
319 {
320 struct slre slre;
321 char data[SLRE_BUFSZ];
322 char nbuf[SLRE_PATSZ];
323 const char *value;
324 int len;
325 int ret;
326
327 if (!name)
328 return 1;
329
330 if (slre_compile(&slre, r) == 0) {
331 printf("Error compiling regex: %s\n", slre.err_str);
332 return 1;
333 }
334
335 if (!t) {
336 value = env_get(name);
337 if (!value) {
338 printf("## Error: variable \"%s\" not defined\n", name);
339 return 1;
340 }
341 t = value;
342 }
343
344 debug("REGEX on %s=%s\n", name, t);
345 debug("REGEX=\"%s\", SUBST=\"%s\", GLOBAL=%d\n", r, s ? s : "<NULL>",
346 global);
347
348 len = strlen(t);
349 if (len + 1 > SLRE_BUFSZ) {
350 printf("## error: subst buffer overflow: have %d, need %d\n",
351 SLRE_BUFSZ, len + 1);
352 return 1;
353 }
354
355 strcpy(data, t);
356
357 ret = setexpr_regex_sub(data, SLRE_BUFSZ, nbuf, SLRE_PATSZ, r, s,
358 global);
359 if (ret)
360 return 1;
361
362 printf("%s=%s\n", name, data);
363
364 return env_set(name, data);
365 }
366 #endif
367
do_setexpr(struct cmd_tbl * cmdtp,int flag,int argc,char * const argv[])368 static int do_setexpr(struct cmd_tbl *cmdtp, int flag, int argc,
369 char *const argv[])
370 {
371 struct expr_arg aval, bval;
372 ulong value;
373 int ret = 0;
374 int w;
375
376 /*
377 * We take 3, 5, or 6 arguments, except fmt operation, which
378 * takes 4 to 8 arguments (limited by _maxargs):
379 * 3 : setexpr name value
380 * 5 : setexpr name val1 op val2
381 * setexpr name [g]sub r s
382 * 6 : setexpr name [g]sub r s t
383 * setexpr name fmt format [val1] [val2] [val3] [val4]
384 */
385
386 if (argc < 3)
387 return CMD_RET_USAGE;
388
389 w = cmd_get_data_size(argv[0], 4);
390
391 if (get_arg(argv[2], w, &aval))
392 return CMD_RET_FAILURE;
393
394 /* format string assignment: "setexpr name fmt %d value" */
395 if (strcmp(argv[2], "fmt") == 0 && IS_ENABLED(CONFIG_CMD_SETEXPR_FMT)) {
396 char str[MAX_STR_LEN];
397 int result;
398
399 if (argc == 3)
400 return CMD_RET_USAGE;
401
402 result = printf_setexpr(str, sizeof(str), argc - 3, &argv[3]);
403 if (result)
404 return result;
405
406 return env_set(argv[1], str);
407 }
408
409 if (argc == 4 || argc > 6)
410 return CMD_RET_USAGE;
411
412 /* plain assignment: "setexpr name value" */
413 if (argc == 3) {
414 if (w == CMD_DATA_SIZE_STR) {
415 ret = env_set(argv[1], aval.sval);
416 free(aval.sval);
417 } else {
418 ret = env_set_hex(argv[1], aval.ival);
419 }
420
421 return ret;
422 }
423
424 /* 5 or 6 args (6 args only with [g]sub) */
425 #ifdef CONFIG_REGEX
426 /*
427 * rexep handling: "setexpr name [g]sub r s [t]"
428 * with 5 args, "t" will be NULL
429 */
430 if (strcmp(argv[2], "gsub") == 0)
431 return regex_sub_var(argv[1], argv[3], argv[4], argv[5], 1);
432
433 if (strcmp(argv[2], "sub") == 0)
434 return regex_sub_var(argv[1], argv[3], argv[4], argv[5], 0);
435 #endif
436
437 /* standard operators: "setexpr name val1 op val2" */
438 if (argc != 5)
439 return CMD_RET_USAGE;
440
441 if (strlen(argv[3]) != 1)
442 return CMD_RET_USAGE;
443
444 if (get_arg(argv[4], w, &bval)) {
445 if (w == CMD_DATA_SIZE_STR)
446 free(aval.sval);
447 return CMD_RET_FAILURE;
448 }
449
450 if (w == CMD_DATA_SIZE_STR) {
451 int len;
452 char *str;
453
454 switch (argv[3][0]) {
455 case '+':
456 len = strlen(aval.sval) + strlen(bval.sval) + 1;
457 str = malloc(len);
458 if (!str) {
459 printf("Out of memory\n");
460 ret = CMD_RET_FAILURE;
461 } else {
462 /* These were copied out and checked earlier */
463 strcpy(str, aval.sval);
464 strcat(str, bval.sval);
465 ret = env_set(argv[1], str);
466 if (ret)
467 printf("Could not set var\n");
468 free(str);
469 }
470 break;
471 default:
472 printf("invalid op\n");
473 ret = 1;
474 }
475 } else {
476 ulong a = aval.ival;
477 ulong b = bval.ival;
478
479 switch (argv[3][0]) {
480 case '|':
481 value = a | b;
482 break;
483 case '&':
484 value = a & b;
485 break;
486 case '+':
487 value = a + b;
488 break;
489 case '^':
490 value = a ^ b;
491 break;
492 case '-':
493 value = a - b;
494 break;
495 case '*':
496 value = a * b;
497 break;
498 case '/':
499 value = a / b;
500 break;
501 case '%':
502 value = a % b;
503 break;
504 default:
505 printf("invalid op\n");
506 return 1;
507 }
508
509 env_set_hex(argv[1], value);
510 }
511
512 if (w == CMD_DATA_SIZE_STR) {
513 free(aval.sval);
514 free(bval.sval);
515 }
516
517 return ret;
518 }
519
520 U_BOOT_CMD(
521 setexpr, 8, 0, do_setexpr,
522 "set environment variable as the result of eval expression",
523 "[.b, .w, .l, .s] name [*]value1 <op> [*]value2\n"
524 " - set environment variable 'name' to the result of the evaluated\n"
525 " expression specified by <op>. <op> can be &, |, ^, +, -, *, /, %\n"
526 " (for strings only + is supported)\n"
527 " size argument is only meaningful if value1 and/or value2 are\n"
528 " memory addresses (*)\n"
529 "setexpr[.b, .w, .l] name [*]value\n"
530 " - load a value into a variable"
531 #ifdef CONFIG_CMD_SETEXPR_FMT
532 "\n"
533 "setexpr name fmt <format> [value1] [value2] [value3] [value4]\n"
534 " - set environment variable 'name' to the result of the bash like\n"
535 " format string evaluation of value."
536 #endif
537 #ifdef CONFIG_REGEX
538 "\n"
539 "setexpr name gsub r s [t]\n"
540 " - For each substring matching the regular expression <r> in the\n"
541 " string <t>, substitute the string <s>. The result is\n"
542 " assigned to <name>. If <t> is not supplied, use the old\n"
543 " value of <name>\n"
544 "setexpr name sub r s [t]\n"
545 " - Just like gsub(), but replace only the first matching substring"
546 #endif
547 );
548