X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=coreutils%2Fexpr.c;h=b247f08db10801fdaaad5e8e7f98f638c8e3cedc;hb=eb1395147ae98e56b455d0f3f9406725fe189822;hp=b23de8e9f8b5061125f5aa7cbe14f6e774ce75f2;hpb=5e678873f9ff7c95d43b278feee547ce989b3b20;p=oweals%2Fbusybox.git

diff --git a/coreutils/expr.c b/coreutils/expr.c
index b23de8e9f..b247f08db 100644
--- a/coreutils/expr.c
+++ b/coreutils/expr.c
@@ -11,22 +11,8 @@
  *  - reduced 464 bytes.
  *  - 64 math support
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- *
+ * 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
@@ -34,41 +20,92 @@
  *
  * 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 <stdio.h>
-#include <string.h>
-#include <stdlib.h>
-#include <regex.h>
-#include <sys/types.h>
-#include <errno.h>
-#include "busybox.h"
-
-
-/* The kinds of value we can have.  */
-enum valtype {
-	integer,
-	string
-};
-typedef enum valtype TYPE;
+ * provided they all associate ((x op x) op x).
+ */
+//config:config EXPR
+//config:	bool "expr (6.6 kb)"
+//config:	default y
+//config:	help
+//config:	expr is used to calculate numbers and print the result
+//config:	to standard output.
+//config:
+//config:config EXPR_MATH_SUPPORT_64
+//config:	bool "Extend Posix numbers support to 64 bit"
+//config:	default y
+//config:	depends on EXPR
+//config:	help
+//config:	Enable 64-bit math support in the expr applet. This will make
+//config:	the applet slightly larger, but will allow computation with very
+//config:	large numbers.
+
+//applet:IF_EXPR(APPLET_NOEXEC(expr, expr, BB_DIR_USR_BIN, BB_SUID_DROP, expr))
+
+//kbuild:lib-$(CONFIG_EXPR) += expr.o
+
+//usage:#define expr_trivial_usage
+//usage:       "EXPRESSION"
+//usage:#define expr_full_usage "\n\n"
+//usage:       "Print the value of EXPRESSION to stdout\n"
+//usage:    "\n"
+//usage:       "EXPRESSION may be:\n"
+//usage:       "	ARG1 | ARG2	ARG1 if it is neither null nor 0, otherwise ARG2\n"
+//usage:       "	ARG1 & ARG2	ARG1 if neither argument is null or 0, otherwise 0\n"
+//usage:       "	ARG1 < ARG2	1 if ARG1 is less than ARG2, else 0. Similarly:\n"
+//usage:       "	ARG1 <= ARG2\n"
+//usage:       "	ARG1 = ARG2\n"
+//usage:       "	ARG1 != ARG2\n"
+//usage:       "	ARG1 >= ARG2\n"
+//usage:       "	ARG1 > ARG2\n"
+//usage:       "	ARG1 + ARG2	Sum of ARG1 and ARG2. Similarly:\n"
+//usage:       "	ARG1 - ARG2\n"
+//usage:       "	ARG1 * ARG2\n"
+//usage:       "	ARG1 / ARG2\n"
+//usage:       "	ARG1 % ARG2\n"
+//usage:       "	STRING : REGEXP		Anchored pattern match of REGEXP in STRING\n"
+//usage:       "	match STRING REGEXP	Same as STRING : REGEXP\n"
+//usage:       "	substr STRING POS LENGTH Substring of STRING, POS counted from 1\n"
+//usage:       "	index STRING CHARS	Index in STRING where any CHARS is found, or 0\n"
+//usage:       "	length STRING		Length of STRING\n"
+//usage:       "	quote TOKEN		Interpret TOKEN as a string, even if\n"
+//usage:       "				it is a keyword like 'match' or an\n"
+//usage:       "				operator like '/'\n"
+//usage:       "	(EXPRESSION)		Value of EXPRESSION\n"
+//usage:       "\n"
+//usage:       "Beware that many operators need to be escaped or quoted for shells.\n"
+//usage:       "Comparisons are arithmetic if both ARGs are numbers, else\n"
+//usage:       "lexicographical. Pattern matches return the string matched between\n"
+//usage:       "\\( and \\) or null; if \\( and \\) are not used, they return the number\n"
+//usage:       "of characters matched or 0."
+
+#include "libbb.h"
+#include "common_bufsiz.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 {
-	TYPE type;                      /* Which kind. */
+	smallint type;                  /* Which kind. */
 	union {                         /* The value itself. */
 		arith_t i;
 		char *s;
@@ -77,100 +114,79 @@ struct valinfo {
 typedef struct valinfo VALUE;
 
 /* The arguments given to the program, minus the program name.  */
-static char **args;
-
-static VALUE *docolon (VALUE *sv, VALUE *pv);
-static VALUE *eval (void);
-static VALUE *int_value (arith_t i);
-static VALUE *str_value (char *s);
-static int nextarg (char *str);
-static int null (VALUE *v);
-static int toarith (VALUE *v);
-static void freev (VALUE *v);
-static void tostring (VALUE *v);
-
-int expr_main (int argc, char **argv)
-{
-	VALUE *v;
+struct globals {
+	char **args;
+} FIX_ALIASING;
+#define G (*(struct globals*)bb_common_bufsiz1)
+#define INIT_G() do { \
+	setup_common_bufsiz(); \
+	/* NB: noexec applet - globals not zeroed */ \
+} while (0)
 
-	if (argc == 1) {
-		bb_error_msg_and_die("too few arguments");
-	}
-
-	args = argv + 1;
+/* forward declarations */
+static VALUE *eval(void);
 
-	v = eval ();
-	if (*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);
-
-	exit (null (v));
-}
 
 /* Return a VALUE for I.  */
 
-static VALUE *int_value (arith_t i)
+static VALUE *int_value(arith_t i)
 {
 	VALUE *v;
 
-	v = xmalloc (sizeof(VALUE));
-	v->type = integer;
+	v = xzalloc(sizeof(VALUE));
+	if (INTEGER) /* otherwise xzalloc did it already */
+		v->type = INTEGER;
 	v->u.i = i;
 	return v;
 }
 
 /* Return a VALUE for S.  */
 
-static VALUE *str_value (char *s)
+static VALUE *str_value(const char *s)
 {
 	VALUE *v;
 
-	v = xmalloc (sizeof(VALUE));
-	v->type = string;
-	v->u.s = bb_xstrdup (s);
+	v = xzalloc(sizeof(VALUE));
+	if (STRING) /* otherwise xzalloc did it already */
+		v->type = STRING;
+	v->u.s = xstrdup(s);
 	return v;
 }
 
 /* Free VALUE V, including structure components.  */
 
-static void freev (VALUE *v)
+static void freev(VALUE *v)
 {
-	if (v->type == string)
-		free (v->u.s);
-	free (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)
+static int null(VALUE *v)
 {
-	switch (v->type) {
-		case integer:
-			return v->u.i == 0;
-		default: /* string: */
-			return v->u.s[0] == '\0' || strcmp (v->u.s, "0") == 0;
-	}
+	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).  */
+/* Coerce V to a STRING value (can't fail).  */
 
-static void tostring (VALUE *v)
+static void tostring(VALUE *v)
 {
-	if (v->type == integer) {
-		v->u.s = bb_xasprintf ("%" PF_REZ "d", PF_REZ_TYPE v->u.i);
-		v->type = string;
+	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.  */
+/* Coerce V to an INTEGER value.  Return 1 on success, 0 on failure.  */
 
-static int toarith (VALUE *v)
+static bool toarith(VALUE *v)
 {
-	if(v->type == string) {
+	if (v->type == STRING) {
 		arith_t i;
 		char *e;
 
@@ -179,231 +195,225 @@ static int toarith (VALUE *v)
 		i = STRTOL(v->u.s, &e, 10);
 		if ((v->u.s == e) || *e)
 			return 0;
-		free (v->u.s);
+		free(v->u.s);
 		v->u.i = i;
-		v->type = integer;
+		v->type = INTEGER;
 	}
 	return 1;
 }
 
-/* Return nonzero if the next token matches STR exactly.
+/* Return str[0]+str[1] if the next token matches STR exactly.
    STR must not be NULL.  */
 
-static int
-nextarg (char *str)
+static int nextarg(const char *str)
 {
-	if (*args == NULL)
+	if (*G.args == NULL || strcmp(*G.args, str) != 0)
 		return 0;
-	return strcmp (*args, str) == 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)
+static int cmp_common(VALUE *l, VALUE *r, int op)
 {
-	int cmpval;
-
-	if (l->type == string || r->type == string) {
-		tostring (l);
-		tostring (r);
-		cmpval = strcmp (l->u.s, r->u.s);
-	}
-	else
-		cmpval = l->u.i - r->u.i;
-	switch(op) {
-		case '<':
-			return cmpval < 0;
-		case ('L'+'E'):
-			return cmpval <= 0;
-		case '=':
-			return cmpval == 0;
-		case '!':
-			return cmpval != 0;
-		case '>':
-			return cmpval > 0;
-		default: /* >= */
-			return cmpval >= 0;
+	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)
+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 == '/' || op == '%') && ri == 0)
-    bb_error_msg_and_die ( "division by zero");
-  switch(op) {
-	case '+':
+	arith_t li, ri;
+
+	if (!toarith(l) || !toarith(r))
+		bb_simple_error_msg_and_die("non-numeric argument");
+	li = l->u.i;
+	ri = r->u.i;
+	if (op == '+')
 		return li + ri;
-	case '-':
+	if (op == '-')
 		return li - ri;
-	case '*':
+	if (op == '*')
 		return li * ri;
-	case '/':
+	if (ri == 0)
+		bb_simple_error_msg_and_die("division by zero");
+	if (op == '/')
 		return li / ri;
-	default:
-		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)
+static VALUE *docolon(VALUE *sv, VALUE *pv)
 {
+	enum { NMATCH = 2 };
 	VALUE *v;
 	regex_t re_buffer;
-	const int NMATCH = 2;
 	regmatch_t re_regs[NMATCH];
 
-	tostring (sv);
-	tostring (pv);
+	tostring(sv);
+	tostring(pv);
 
 	if (pv->u.s[0] == '^') {
-		fprintf (stderr, "\
-warning: unportable BRE: `%s': using `^' as the first character\n\
-of a basic regular expression is not portable; it is being ignored",
-		pv->u.s);
+		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));
-	if( regcomp (&re_buffer, pv->u.s, 0) != 0 )
-		bb_error_msg_and_die("Invalid regular expression");
+	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) {
+	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) {
+		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);
+			v = str_value(sv->u.s + re_regs[1].rm_so);
+		} else {
+			v = int_value(re_regs[0].rm_eo);
 		}
-		else
-			v = int_value (re_regs[0].rm_eo);
-	}
-	else {
+	} else {
 		/* Match failed -- return the right kind of null.  */
 		if (re_buffer.re_nsub > 0)
-			v = str_value ("");
+			v = str_value("");
 		else
-			v = int_value (0);
+			v = int_value(0);
 	}
+	regfree(&re_buffer);
 	return v;
 }
 
 /* Handle bare operands and ( expr ) syntax.  */
 
-static VALUE *eval7 (void)
+static VALUE *eval7(void)
 {
 	VALUE *v;
 
-	if (!*args)
-		bb_error_msg_and_die ( "syntax error");
+	if (!*G.args)
+		bb_simple_error_msg_and_die("syntax error");
 
-	if (nextarg ("(")) {
-		args++;
-		v = eval ();
-		if (!nextarg (")"))
-			bb_error_msg_and_die ( "syntax error");
-			args++;
-			return v;
-		}
+	if (nextarg("(")) {
+		G.args++;
+		v = eval();
+		if (!nextarg(")"))
+			bb_simple_error_msg_and_die("syntax error");
+		G.args++;
+		return v;
+	}
 
-	if (nextarg (")"))
-		bb_error_msg_and_die ( "syntax error");
+	if (nextarg(")"))
+		bb_simple_error_msg_and_die("syntax error");
 
-	return str_value (*args++);
+	return str_value(*G.args++);
 }
 
 /* Handle match, substr, index, length, and quote keywords.  */
 
-static VALUE *eval6 (void)
+static VALUE *eval6(void)
 {
-	VALUE *l, *r, *v, *i1, *i2;
-
-	if (nextarg ("quote")) {
-		args++;
-		if (!*args)
-			bb_error_msg_and_die ( "syntax error");
-		return str_value (*args++);
+	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_simple_error_msg_and_die("syntax error");
+		return str_value(*G.args++);
 	}
-	else if (nextarg ("length")) {
-		args++;
-		r = eval6 ();
-		tostring (r);
-		v = int_value (strlen (r->u.s));
-		freev (r);
-		return v;
+	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);
 	}
-	else if (nextarg ("match")) {
-		args++;
-		l = eval6 ();
-		r = eval6 ();
-		v = docolon (l, r);
-		freev (l);
-		freev (r);
-		return v;
-	}
-	else if (nextarg ("index")) {
-		args++;
-		l = eval6 ();
-		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)
+	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);
-		return v;
+		freev(l);
+		freev(r);
 	}
-	else if (nextarg ("substr")) {
-		args++;
-		l = eval6 ();
-		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 ("");
+	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 = bb_xstrndup(l->u.s + i1->u.i - 1, i2->u.i);
+			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;
+		freev(l);
+		freev(i1);
+		freev(i2);
 	}
-	else
-		return eval7 ();
+	return v;
 }
 
 /* Handle : operator (pattern matching).
    Calls docolon to do the real work.  */
 
-static VALUE *eval5 (void)
+static VALUE *eval5(void)
 {
 	VALUE *l, *r, *v;
 
-	l = eval6 ();
-	while (nextarg (":")) {
-		args++;
-		r = eval6 ();
-		v = docolon (l, r);
-		freev (l);
-		freev (r);
+	l = eval6();
+	while (nextarg(":")) {
+		G.args++;
+		r = eval6();
+		v = docolon(l, r);
+		freev(l);
+		freev(r);
 		l = v;
 	}
 	return l;
@@ -411,128 +421,139 @@ static VALUE *eval5 (void)
 
 /* Handle *, /, % operators.  */
 
-static VALUE *eval4 (void)
+static VALUE *eval4(void)
 {
 	VALUE *l, *r;
 	int op;
 	arith_t val;
 
-	l = eval5 ();
+	l = eval5();
 	while (1) {
-		if (nextarg ("*"))
-			op = '*';
-		else if (nextarg ("/"))
-			op = '/';
-		else if (nextarg ("%"))
-			op = '%';
-		else
-			return l;
-		args++;
-		r = eval5 ();
-		val = arithmetic_common (l, r, op);
-		freev (l);
-		freev (r);
-		l = int_value (val);
+		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)
+static VALUE *eval3(void)
 {
 	VALUE *l, *r;
 	int op;
 	arith_t val;
 
-	l = eval4 ();
+	l = eval4();
 	while (1) {
-		if (nextarg ("+"))
-			op = '+';
-		else if (nextarg ("-"))
-			op = '-';
-		else
-			return l;
-		args++;
-		r = eval4 ();
-		val = arithmetic_common (l, r, op);
-		freev (l);
-		freev (r);
-		l = int_value (val);
+		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)
+static VALUE *eval2(void)
 {
 	VALUE *l, *r;
 	int op;
 	arith_t val;
 
-	l = eval3 ();
+	l = eval3();
 	while (1) {
-		if (nextarg ("<"))
-			op = '<';
-		else if (nextarg ("<="))
-			op = 'L'+'E';
-		else if (nextarg ("=") || nextarg ("=="))
-			op = '=';
-		else if (nextarg ("!="))
-			op = '!';
-		else if (nextarg (">="))
-			op = 'G'+'E';
-		else if (nextarg (">"))
-			op = '>';
-		else
-			return l;
-		args++;
-		r = eval3 ();
-		toarith (l);
-		toarith (r);
-		val = cmp_common (l, r, op);
-		freev (l);
-		freev (r);
-		l = int_value (val);
+		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)
+static VALUE *eval1(void)
 {
 	VALUE *l, *r;
 
-	l = eval2 ();
-	while (nextarg ("&")) {
-		args++;
-		r = eval2 ();
-		if (null (l) || null (r)) {
-			freev (l);
-			freev (r);
-			l = int_value (0);
-		}
-		else
-			freev (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)
+static VALUE *eval(void)
 {
 	VALUE *l, *r;
 
-	l = eval1 ();
-	while (nextarg ("|")) {
-		args++;
-		r = eval1 ();
-		if (null (l)) {
-			freev (l);
+	l = eval1();
+	while (nextarg("|")) {
+		G.args++;
+		r = eval1();
+		if (null(l)) {
+			freev(l);
 			l = r;
-		}
-		else
-			freev (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;
+
+	INIT_G();
+
+	xfunc_error_retval = 2; /* coreutils compat */
+	G.args = argv + 1;
+	if (*G.args == NULL) {
+		bb_simple_error_msg_and_die("too few arguments");
+	}
+	v = eval();
+	if (*G.args)
+		bb_simple_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));
+}