| /* vi: set sw=4 ts=4: */ |
| /* |
| * Mini expr implementation for busybox |
| * |
| * based on GNU expr Mike Parker. |
| * Copyright (C) 86, 1991-1997, 1999 Free Software Foundation, Inc. |
| * |
| * Busybox modifications |
| * Copyright (c) 2000 Edward Betts <edward@debian.org>. |
| * Copyright (C) 2003-2005 Vladimir Oleynik <dzo@simtreas.ru> |
| * - reduced 464 bytes. |
| * - 64 math support |
| * |
| * Licensed under GPLv2 or later, see file LICENSE in this source tree. |
| */ |
| |
| /* This program evaluates expressions. Each token (operator, operand, |
| * parenthesis) of the expression must be a separate argument. The |
| * parser used is a reasonably general one, though any incarnation of |
| * it is language-specific. It is especially nice for expressions. |
| * |
| * No parse tree is needed; a new node is evaluated immediately. |
| * One function can handle multiple operators all of equal precedence, |
| * provided they all associate ((x op x) op x). */ |
| |
| /* no getopt needed */ |
| |
| #include "libbb.h" |
| #include "xregex.h" |
| |
| #if ENABLE_EXPR_MATH_SUPPORT_64 |
| typedef int64_t arith_t; |
| |
| #define PF_REZ "ll" |
| #define PF_REZ_TYPE (long long) |
| #define STRTOL(s, e, b) strtoll(s, e, b) |
| #else |
| typedef long arith_t; |
| |
| #define PF_REZ "l" |
| #define PF_REZ_TYPE (long) |
| #define STRTOL(s, e, b) strtol(s, e, b) |
| #endif |
| |
| /* TODO: use bb_strtol[l]? It's easier to check for errors... */ |
| |
| /* The kinds of value we can have. */ |
| enum { |
| INTEGER, |
| STRING |
| }; |
| |
| /* A value is.... */ |
| struct valinfo { |
| smallint type; /* Which kind. */ |
| union { /* The value itself. */ |
| arith_t i; |
| char *s; |
| } u; |
| }; |
| typedef struct valinfo VALUE; |
| |
| /* The arguments given to the program, minus the program name. */ |
| struct globals { |
| char **args; |
| } FIX_ALIASING; |
| #define G (*(struct globals*)&bb_common_bufsiz1) |
| |
| /* forward declarations */ |
| static VALUE *eval(void); |
| |
| |
| /* Return a VALUE for I. */ |
| |
| static VALUE *int_value(arith_t i) |
| { |
| VALUE *v; |
| |
| v = xzalloc(sizeof(VALUE)); |
| if (INTEGER) /* otherwise xzaaloc did it already */ |
| v->type = INTEGER; |
| v->u.i = i; |
| return v; |
| } |
| |
| /* Return a VALUE for S. */ |
| |
| static VALUE *str_value(const char *s) |
| { |
| VALUE *v; |
| |
| v = xzalloc(sizeof(VALUE)); |
| if (STRING) /* otherwise xzaaloc did it already */ |
| v->type = STRING; |
| v->u.s = xstrdup(s); |
| return v; |
| } |
| |
| /* Free VALUE V, including structure components. */ |
| |
| static void freev(VALUE *v) |
| { |
| if (v->type == STRING) |
| free(v->u.s); |
| free(v); |
| } |
| |
| /* Return nonzero if V is a null-string or zero-number. */ |
| |
| static int null(VALUE *v) |
| { |
| if (v->type == INTEGER) |
| return v->u.i == 0; |
| /* STRING: */ |
| return v->u.s[0] == '\0' || LONE_CHAR(v->u.s, '0'); |
| } |
| |
| /* Coerce V to a STRING value (can't fail). */ |
| |
| static void tostring(VALUE *v) |
| { |
| if (v->type == INTEGER) { |
| v->u.s = xasprintf("%" PF_REZ "d", PF_REZ_TYPE v->u.i); |
| v->type = STRING; |
| } |
| } |
| |
| /* Coerce V to an INTEGER value. Return 1 on success, 0 on failure. */ |
| |
| static bool toarith(VALUE *v) |
| { |
| if (v->type == STRING) { |
| arith_t i; |
| char *e; |
| |
| /* Don't interpret the empty string as an integer. */ |
| /* Currently does not worry about overflow or int/long differences. */ |
| i = STRTOL(v->u.s, &e, 10); |
| if ((v->u.s == e) || *e) |
| return 0; |
| free(v->u.s); |
| v->u.i = i; |
| v->type = INTEGER; |
| } |
| return 1; |
| } |
| |
| /* Return str[0]+str[1] if the next token matches STR exactly. |
| STR must not be NULL. */ |
| |
| static int nextarg(const char *str) |
| { |
| if (*G.args == NULL || strcmp(*G.args, str) != 0) |
| return 0; |
| return (unsigned char)str[0] + (unsigned char)str[1]; |
| } |
| |
| /* The comparison operator handling functions. */ |
| |
| static int cmp_common(VALUE *l, VALUE *r, int op) |
| { |
| arith_t ll, rr; |
| |
| ll = l->u.i; |
| rr = r->u.i; |
| if (l->type == STRING || r->type == STRING) { |
| tostring(l); |
| tostring(r); |
| ll = strcmp(l->u.s, r->u.s); |
| rr = 0; |
| } |
| /* calculating ll - rr and checking the result is prone to overflows. |
| * We'll do it differently: */ |
| if (op == '<') |
| return ll < rr; |
| if (op == ('<' + '=')) |
| return ll <= rr; |
| if (op == '=' || (op == '=' + '=')) |
| return ll == rr; |
| if (op == '!' + '=') |
| return ll != rr; |
| if (op == '>') |
| return ll > rr; |
| /* >= */ |
| return ll >= rr; |
| } |
| |
| /* The arithmetic operator handling functions. */ |
| |
| static arith_t arithmetic_common(VALUE *l, VALUE *r, int op) |
| { |
| arith_t li, ri; |
| |
| if (!toarith(l) || !toarith(r)) |
| bb_error_msg_and_die("non-numeric argument"); |
| li = l->u.i; |
| ri = r->u.i; |
| if (op == '+') |
| return li + ri; |
| if (op == '-') |
| return li - ri; |
| if (op == '*') |
| return li * ri; |
| if (ri == 0) |
| bb_error_msg_and_die("division by zero"); |
| if (op == '/') |
| return li / ri; |
| return li % ri; |
| } |
| |
| /* Do the : operator. |
| SV is the VALUE for the lhs (the string), |
| PV is the VALUE for the rhs (the pattern). */ |
| |
| static VALUE *docolon(VALUE *sv, VALUE *pv) |
| { |
| enum { NMATCH = 2 }; |
| VALUE *v; |
| regex_t re_buffer; |
| regmatch_t re_regs[NMATCH]; |
| |
| tostring(sv); |
| tostring(pv); |
| |
| if (pv->u.s[0] == '^') { |
| bb_error_msg( |
| "warning: '%s': using '^' as the first character\n" |
| "of a basic regular expression is not portable; it is ignored", pv->u.s); |
| } |
| |
| memset(&re_buffer, 0, sizeof(re_buffer)); |
| memset(re_regs, 0, sizeof(re_regs)); |
| xregcomp(&re_buffer, pv->u.s, 0); |
| |
| /* expr uses an anchored pattern match, so check that there was a |
| * match and that the match starts at offset 0. */ |
| if (regexec(&re_buffer, sv->u.s, NMATCH, re_regs, 0) != REG_NOMATCH |
| && re_regs[0].rm_so == 0 |
| ) { |
| /* Were \(...\) used? */ |
| if (re_buffer.re_nsub > 0 && re_regs[1].rm_so >= 0) { |
| sv->u.s[re_regs[1].rm_eo] = '\0'; |
| v = str_value(sv->u.s + re_regs[1].rm_so); |
| } else { |
| v = int_value(re_regs[0].rm_eo); |
| } |
| } else { |
| /* Match failed -- return the right kind of null. */ |
| if (re_buffer.re_nsub > 0) |
| v = str_value(""); |
| else |
| v = int_value(0); |
| } |
| regfree(&re_buffer); |
| return v; |
| } |
| |
| /* Handle bare operands and ( expr ) syntax. */ |
| |
| static VALUE *eval7(void) |
| { |
| VALUE *v; |
| |
| if (!*G.args) |
| bb_error_msg_and_die("syntax error"); |
| |
| if (nextarg("(")) { |
| G.args++; |
| v = eval(); |
| if (!nextarg(")")) |
| bb_error_msg_and_die("syntax error"); |
| G.args++; |
| return v; |
| } |
| |
| if (nextarg(")")) |
| bb_error_msg_and_die("syntax error"); |
| |
| return str_value(*G.args++); |
| } |
| |
| /* Handle match, substr, index, length, and quote keywords. */ |
| |
| static VALUE *eval6(void) |
| { |
| static const char keywords[] ALIGN1 = |
| "quote\0""length\0""match\0""index\0""substr\0"; |
| |
| VALUE *r, *i1, *i2; |
| VALUE *l = l; /* silence gcc */ |
| VALUE *v = v; /* silence gcc */ |
| int key = *G.args ? index_in_strings(keywords, *G.args) + 1 : 0; |
| |
| if (key == 0) /* not a keyword */ |
| return eval7(); |
| G.args++; /* We have a valid token, so get the next argument. */ |
| if (key == 1) { /* quote */ |
| if (!*G.args) |
| bb_error_msg_and_die("syntax error"); |
| return str_value(*G.args++); |
| } |
| if (key == 2) { /* length */ |
| r = eval6(); |
| tostring(r); |
| v = int_value(strlen(r->u.s)); |
| freev(r); |
| } else |
| l = eval6(); |
| |
| if (key == 3) { /* match */ |
| r = eval6(); |
| v = docolon(l, r); |
| freev(l); |
| freev(r); |
| } |
| if (key == 4) { /* index */ |
| r = eval6(); |
| tostring(l); |
| tostring(r); |
| v = int_value(strcspn(l->u.s, r->u.s) + 1); |
| if (v->u.i == (arith_t) strlen(l->u.s) + 1) |
| v->u.i = 0; |
| freev(l); |
| freev(r); |
| } |
| if (key == 5) { /* substr */ |
| i1 = eval6(); |
| i2 = eval6(); |
| tostring(l); |
| if (!toarith(i1) || !toarith(i2) |
| || i1->u.i > (arith_t) strlen(l->u.s) |
| || i1->u.i <= 0 || i2->u.i <= 0) |
| v = str_value(""); |
| else { |
| v = xmalloc(sizeof(VALUE)); |
| v->type = STRING; |
| v->u.s = xstrndup(l->u.s + i1->u.i - 1, i2->u.i); |
| } |
| freev(l); |
| freev(i1); |
| freev(i2); |
| } |
| return v; |
| } |
| |
| /* Handle : operator (pattern matching). |
| Calls docolon to do the real work. */ |
| |
| static VALUE *eval5(void) |
| { |
| VALUE *l, *r, *v; |
| |
| l = eval6(); |
| while (nextarg(":")) { |
| G.args++; |
| r = eval6(); |
| v = docolon(l, r); |
| freev(l); |
| freev(r); |
| l = v; |
| } |
| return l; |
| } |
| |
| /* Handle *, /, % operators. */ |
| |
| static VALUE *eval4(void) |
| { |
| VALUE *l, *r; |
| int op; |
| arith_t val; |
| |
| l = eval5(); |
| while (1) { |
| op = nextarg("*"); |
| if (!op) { op = nextarg("/"); |
| if (!op) { op = nextarg("%"); |
| if (!op) return l; |
| }} |
| G.args++; |
| r = eval5(); |
| val = arithmetic_common(l, r, op); |
| freev(l); |
| freev(r); |
| l = int_value(val); |
| } |
| } |
| |
| /* Handle +, - operators. */ |
| |
| static VALUE *eval3(void) |
| { |
| VALUE *l, *r; |
| int op; |
| arith_t val; |
| |
| l = eval4(); |
| while (1) { |
| op = nextarg("+"); |
| if (!op) { |
| op = nextarg("-"); |
| if (!op) return l; |
| } |
| G.args++; |
| r = eval4(); |
| val = arithmetic_common(l, r, op); |
| freev(l); |
| freev(r); |
| l = int_value(val); |
| } |
| } |
| |
| /* Handle comparisons. */ |
| |
| static VALUE *eval2(void) |
| { |
| VALUE *l, *r; |
| int op; |
| arith_t val; |
| |
| l = eval3(); |
| while (1) { |
| op = nextarg("<"); |
| if (!op) { op = nextarg("<="); |
| if (!op) { op = nextarg("="); |
| if (!op) { op = nextarg("=="); |
| if (!op) { op = nextarg("!="); |
| if (!op) { op = nextarg(">="); |
| if (!op) { op = nextarg(">"); |
| if (!op) return l; |
| }}}}}} |
| G.args++; |
| r = eval3(); |
| toarith(l); |
| toarith(r); |
| val = cmp_common(l, r, op); |
| freev(l); |
| freev(r); |
| l = int_value(val); |
| } |
| } |
| |
| /* Handle &. */ |
| |
| static VALUE *eval1(void) |
| { |
| VALUE *l, *r; |
| |
| l = eval2(); |
| while (nextarg("&")) { |
| G.args++; |
| r = eval2(); |
| if (null(l) || null(r)) { |
| freev(l); |
| freev(r); |
| l = int_value(0); |
| } else |
| freev(r); |
| } |
| return l; |
| } |
| |
| /* Handle |. */ |
| |
| static VALUE *eval(void) |
| { |
| VALUE *l, *r; |
| |
| l = eval1(); |
| while (nextarg("|")) { |
| G.args++; |
| r = eval1(); |
| if (null(l)) { |
| freev(l); |
| l = r; |
| } else |
| freev(r); |
| } |
| return l; |
| } |
| |
| int expr_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
| int expr_main(int argc UNUSED_PARAM, char **argv) |
| { |
| VALUE *v; |
| |
| xfunc_error_retval = 2; /* coreutils compat */ |
| G.args = argv + 1; |
| if (*G.args == NULL) { |
| bb_error_msg_and_die("too few arguments"); |
| } |
| v = eval(); |
| if (*G.args) |
| bb_error_msg_and_die("syntax error"); |
| if (v->type == INTEGER) |
| printf("%" PF_REZ "d\n", PF_REZ_TYPE v->u.i); |
| else |
| puts(v->u.s); |
| fflush_stdout_and_exit(null(v)); |
| } |