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cmd/setexpr.c
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/* * Copyright 2008 Freescale Semiconductor, Inc. * Copyright 2013 Wolfgang Denk <wd@denx.de> * * SPDX-License-Identifier: GPL-2.0+ */ /* * This file provides a shell like 'expr' function to return. */ #include <common.h> #include <config.h> #include <command.h> #include <mapmem.h> static ulong get_arg(char *s, int w) { /* * If the parameter starts with a '*' then assume it is a pointer to * the value we want. */ if (s[0] == '*') { ulong *p; ulong addr; ulong val; addr = simple_strtoul(&s[1], NULL, 16); switch (w) { case 1: p = map_sysmem(addr, sizeof(uchar)); val = (ulong)*(uchar *)p; unmap_sysmem(p); return val; case 2: p = map_sysmem(addr, sizeof(ushort)); val = (ulong)*(ushort *)p; unmap_sysmem(p); return val; case 4: default: p = map_sysmem(addr, sizeof(ulong)); val = *p; unmap_sysmem(p); return val; } } else { return simple_strtoul(s, NULL, 16); } } #ifdef CONFIG_REGEX #include <slre.h> #define SLRE_BUFSZ 16384 #define SLRE_PATSZ 4096 /* * memstr - Find the first substring in memory * @s1: The string to be searched * @s2: The string to search for * * Similar to and based on strstr(), * but strings do not need to be NUL terminated. */ static char *memstr(const char *s1, int l1, const char *s2, int l2) { if (!l2) return (char *)s1; while (l1 >= l2) { l1--; if (!memcmp(s1, s2, l2)) return (char *)s1; s1++; } return NULL; } static char *substitute(char *string, /* string buffer */ int *slen, /* current string length */ int ssize, /* string bufer size */ const char *old,/* old (replaced) string */ int olen, /* length of old string */ const char *new,/* new (replacement) string */ int nlen) /* length of new string */ { char *p = memstr(string, *slen, old, olen); if (p == NULL) return NULL; debug("## Match at pos %ld: match len %d, subst len %d ", (long)(p - string), olen, nlen); /* make sure replacement matches */ if (*slen + nlen - olen > ssize) { printf("## error: substitution buffer overflow "); return NULL; } /* move tail if needed */ if (olen != nlen) { int tail, len; len = (olen > nlen) ? olen : nlen; tail = ssize - (p + len - string); debug("## tail len %d ", tail); memmove(p + nlen, p + olen, tail); } /* insert substitue */ memcpy(p, new, nlen); *slen += nlen - olen; return p + nlen; } /* * Perform regex operations on a environment variable * * Returns 0 if OK, 1 in case of errors. */ static int regex_sub(const char *name, const char *r, const char *s, const char *t, int global) { struct slre slre; char data[SLRE_BUFSZ]; char *datap = data; const char *value; int res, len, nlen, loop; if (name == NULL) return 1; if (slre_compile(&slre, r) == 0) { printf("Error compiling regex: %s ", slre.err_str); return 1; } if (t == NULL) { value = env_get(name); if (value == NULL) { printf("## Error: variable \"%s\" not defined ", name); return 1; } t = value; } debug("REGEX on %s=%s ", name, t); debug("REGEX=\"%s\", SUBST=\"%s\", GLOBAL=%d ", r, s ? s : "<NULL>", global); len = strlen(t); if (len + 1 > SLRE_BUFSZ) { printf("## error: subst buffer overflow: have %d, need %d ", SLRE_BUFSZ, len + 1); return 1; } strcpy(data, t); if (s == NULL) nlen = 0; else nlen = strlen(s); for (loop = 0;; loop++) { struct cap caps[slre.num_caps + 2]; char nbuf[SLRE_PATSZ]; const char *old; char *np; int i, olen; (void) memset(caps, 0, sizeof(caps)); res = slre_match(&slre, datap, len, caps); debug("Result: %d ", res); for (i = 0; i < slre.num_caps; i++) { if (caps[i].len > 0) { debug("Substring %d: [%.*s] ", i, caps[i].len, caps[i].ptr); } } if (res == 0) { if (loop == 0) { printf("%s: No match ", t); return 1; } else { break; } } debug("## MATCH ## %s ", data); if (s == NULL) { printf("%s=%s ", name, t); return 1; } old = caps[0].ptr; olen = caps[0].len; if (nlen + 1 >= SLRE_PATSZ) { printf("## error: pattern buffer overflow: have %d, need %d ", SLRE_BUFSZ, nlen + 1); return 1; } strcpy(nbuf, s); debug("## SUBST(1) ## %s ", nbuf); /* * Handle back references * * Support for \0 ... \9, where \0 is the * whole matched pattern (similar to &). * * Implementation is a bit simpleminded as * backrefs are substituted sequentially, one * by one. This will lead to somewhat * unexpected results if the replacement * strings contain any \N strings then then * may get substitued, too. We accept this * restriction for the sake of simplicity. */ for (i = 0; i < 10; ++i) { char backref[2] = { '\\', '0', }; if (caps[i].len == 0) break; backref[1] += i; debug("## BACKREF %d: replace \"%.*s\" by \"%.*s\" in \"%s\" ", i, 2, backref, caps[i].len, caps[i].ptr, nbuf); for (np = nbuf;;) { char *p = memstr(np, nlen, backref, 2); if (p == NULL) break; np = substitute(np, &nlen, SLRE_PATSZ, backref, 2, caps[i].ptr, caps[i].len); if (np == NULL) return 1; } } debug("## SUBST(2) ## %s ", nbuf); datap = substitute(datap, &len, SLRE_BUFSZ, old, olen, nbuf, nlen); if (datap == NULL) return 1; debug("## REMAINDER: %s ", datap); debug("## RESULT: %s ", data); if (!global) break; } debug("## FINAL (now env_set()) : %s ", data); printf("%s=%s ", name, data); return env_set(name, data); } #endif static int do_setexpr(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { ulong a, b; ulong value; int w; /* * We take 3, 5, or 6 arguments: * 3 : setexpr name value * 5 : setexpr name val1 op val2 * setexpr name [g]sub r s * 6 : setexpr name [g]sub r s t */ /* > 6 already tested by max command args */ if ((argc < 3) || (argc == 4)) return CMD_RET_USAGE; w = cmd_get_data_size(argv[0], 4); a = get_arg(argv[2], w); /* plain assignment: "setexpr name value" */ if (argc == 3) { env_set_hex(argv[1], a); return 0; } /* 5 or 6 args (6 args only with [g]sub) */ #ifdef CONFIG_REGEX /* * rexep handling: "setexpr name [g]sub r s [t]" * with 5 args, "t" will be NULL */ if (strcmp(argv[2], "gsub") == 0) return regex_sub(argv[1], argv[3], argv[4], argv[5], 1); if (strcmp(argv[2], "sub") == 0) return regex_sub(argv[1], argv[3], argv[4], argv[5], 0); #endif /* standard operators: "setexpr name val1 op val2" */ if (argc != 5) return CMD_RET_USAGE; if (strlen(argv[3]) != 1) return CMD_RET_USAGE; b = get_arg(argv[4], w); switch (argv[3][0]) { case '|': value = a | b; break; case '&': value = a & b; break; case '+': value = a + b; break; case '^': value = a ^ b; break; case '-': value = a - b; break; case '*': value = a * b; break; case '/': value = a / b; break; case '%': value = a % b; break; default: printf("invalid op "); return 1; } env_set_hex(argv[1], value); return 0; } U_BOOT_CMD( setexpr, 6, 0, do_setexpr, "set environment variable as the result of eval expression", "[.b, .w, .l] name [*]value1 <op> [*]value2 " " - set environment variable 'name' to the result of the evaluated " " expression specified by <op>. <op> can be &, |, ^, +, -, *, /, % " " size argument is only meaningful if value1 and/or value2 are " " memory addresses (*) " "setexpr[.b, .w, .l] name [*]value " " - load a value into a variable" #ifdef CONFIG_REGEX " " "setexpr name gsub r s [t] " " - For each substring matching the regular expression <r> in the " " string <t>, substitute the string <s>. The result is " " assigned to <name>. If <t> is not supplied, use the old " " value of <name> " "setexpr name sub r s [t] " " - Just like gsub(), but replace only the first matching substring" #endif ); |