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fa717604a4
freebsd-dev/bin/expr/expr.y
Stefan Eßer fa717604a4 Make /bin/expr support 64bit numeric range and range checks by default, 
again. This brings back the behaviour of expr in FreeBSD-4, which had been
reverted due to an assumed incompatbility with POSIX.1 for FreeBSD-5.

This issue has been discussed in the freebsd-standards list, and the
consensus was, that POSIX.1 is in fact not violated by this extension,
since it affects only cases of POSIX undefined behaviour (overflow of
signed long).

Other operating systems did upgrade their versions of expr to support
64bit range, after it had been initially brought to FreeBSD. They have
used it for a decade without problems, meanwhile.

The -e option is retained, but it will only select less strict checking
of numeric parameters (leading white-space, leading "+" are allowed and
skipped, an empty string is considered to represent 0 in numeric context.)
The call of check_utility_compat() as a means of establishing backwards
compatibility with FreeBSD-4 is considered obsolete, but preserved in
this commit. It is expected to be removed in a later revision of this
file.
Reviewed by:	bde, das, jilles
MFC after:	2 month (those parts that do not violate POLA)
2011-07-09 12:05:53 +00:00

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%{
/*-
* Written by Pace Willisson (pace@blitz.com)
* and placed in the public domain.
*
* Largely rewritten by J.T. Conklin (jtc@wimsey.com)
*
* $FreeBSD$
*/
#include <sys/types.h>
#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <inttypes.h>
#include <limits.h>
#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <regex.h>
#include <unistd.h>
/*
* POSIX specifies a specific error code for syntax errors. We exit
* with this code for all errors.
*/
#define ERR_EXIT 2
enum valtype {
integer, numeric_string, string
} ;
struct val {
enum valtype type;
union {
char *s;
intmax_t i;
} u;
} ;
struct val *result;
void assert_to_integer(struct val *);
int chk_div(intmax_t, intmax_t);
int chk_minus(intmax_t, intmax_t, intmax_t);
int chk_plus(intmax_t, intmax_t, intmax_t);
int chk_times(intmax_t, intmax_t, intmax_t);
void free_value(struct val *);
int is_integer(const char *);
int isstring(struct val *);
int is_zero_or_null(struct val *);
struct val *make_integer(intmax_t);
struct val *make_str(const char *);
struct val *op_and(struct val *, struct val *);
struct val *op_colon(struct val *, struct val *);
struct val *op_div(struct val *, struct val *);
struct val *op_eq(struct val *, struct val *);
struct val *op_ge(struct val *, struct val *);
struct val *op_gt(struct val *, struct val *);
struct val *op_le(struct val *, struct val *);
struct val *op_lt(struct val *, struct val *);
struct val *op_minus(struct val *, struct val *);
struct val *op_ne(struct val *, struct val *);
struct val *op_or(struct val *, struct val *);
struct val *op_plus(struct val *, struct val *);
struct val *op_rem(struct val *, struct val *);
struct val *op_times(struct val *, struct val *);
int to_integer(struct val *);
void to_string(struct val *);
int yyerror(const char *);
int yylex(void);
int yyparse(void);
static int nonposix;
char **av;
%}
%union
{
struct val *val;
}
%left <val> '|'
%left <val> '&'
%left <val> '=' '>' '<' GE LE NE
%left <val> '+' '-'
%left <val> '*' '/' '%'
%left <val> ':'
%token <val> TOKEN
%type <val> start expr
%%
start: expr { result = $$; }
expr: TOKEN
| '(' expr ')' { $$ = $2; }
| expr '|' expr { $$ = op_or ($1, $3); }
| expr '&' expr { $$ = op_and ($1, $3); }
| expr '=' expr { $$ = op_eq ($1, $3); }
| expr '>' expr { $$ = op_gt ($1, $3); }
| expr '<' expr { $$ = op_lt ($1, $3); }
| expr GE expr { $$ = op_ge ($1, $3); }
| expr LE expr { $$ = op_le ($1, $3); }
| expr NE expr { $$ = op_ne ($1, $3); }
| expr '+' expr { $$ = op_plus ($1, $3); }
| expr '-' expr { $$ = op_minus ($1, $3); }
| expr '*' expr { $$ = op_times ($1, $3); }
| expr '/' expr { $$ = op_div ($1, $3); }
| expr '%' expr { $$ = op_rem ($1, $3); }
| expr ':' expr { $$ = op_colon ($1, $3); }
;
%%
struct val *
make_integer(intmax_t i)
{
struct val *vp;
vp = (struct val *) malloc (sizeof (*vp));
if (vp == NULL) {
errx(ERR_EXIT, "malloc() failed");
}
vp->type = integer;
vp->u.i = i;
return vp;
}
struct val *
make_str(const char *s)
{
struct val *vp;
vp = (struct val *) malloc (sizeof (*vp));
if (vp == NULL || ((vp->u.s = strdup (s)) == NULL)) {
errx(ERR_EXIT, "malloc() failed");
}
if (is_integer(s))
vp->type = numeric_string;
else
vp->type = string;
return vp;
}
void
free_value(struct val *vp)
{
if (vp->type == string || vp->type == numeric_string)
free (vp->u.s);
}
int
to_integer(struct val *vp)
{
intmax_t i;
/* we can only convert numeric_string to integer, here */
if (vp->type == numeric_string) {
errno = 0;
i = strtoimax(vp->u.s, (char **)NULL, 10);
/* just keep as numeric_string, if the conversion fails */
if (errno != ERANGE) {
free (vp->u.s);
vp->u.i = i;
vp->type = integer;
}
}
return (vp->type == integer);
}
void
assert_to_integer(struct val *vp)
{
if (vp->type == string)
errx(ERR_EXIT, "not a decimal number: '%s'", vp->u.s);
if (!to_integer(vp))
errx(ERR_EXIT, "operand too large: '%s'", vp->u.s);
}
void
to_string(struct val *vp)
{
char *tmp;
if (vp->type == string || vp->type == numeric_string)
return;
/*
* log_10(x) ~= 0.3 * log_2(x). Rounding up gives the number
* of digits; add one each for the sign and terminating null
* character, respectively.
*/
#define NDIGITS(x) (3 * (sizeof(x) * CHAR_BIT) / 10 + 1 + 1 + 1)
tmp = malloc(NDIGITS(vp->u.i));
if (tmp == NULL)
errx(ERR_EXIT, "malloc() failed");
sprintf(tmp, "%jd", vp->u.i);
vp->type = string;
vp->u.s = tmp;
}
int
is_integer(const char *s)
{
if (nonposix) {
if (*s == '\0')
return (1);
while (isspace((unsigned char)*s))
s++;
}
if (*s == '-' || (nonposix && *s == '+'))
s++;
if (*s == '\0')
return (0);
while (isdigit((unsigned char)*s))
s++;
return (*s == '\0');
}
int
isstring(struct val *vp)
{
/* only TRUE if this string is not a valid integer */
return (vp->type == string);
}
int
yylex(void)
{
char *p;
if (*av == NULL)
return (0);
p = *av++;
if (strlen (p) == 1) {
if (strchr ("|&=<>+-*/%:()", *p))
return (*p);
} else if (strlen (p) == 2 && p[1] == '=') {
switch (*p) {
case '>': return (GE);
case '<': return (LE);
case '!': return (NE);
}
}
yylval.val = make_str (p);
return (TOKEN);
}
int
is_zero_or_null(struct val *vp)
{
if (vp->type == integer) {
return (vp->u.i == 0);
} else {
return (*vp->u.s == 0 || (to_integer (vp) && vp->u.i == 0));
}
/* NOTREACHED */
}
int
main(int argc, char *argv[])
{
int c;
setlocale (LC_ALL, "");
if (getenv("EXPR_COMPAT") != NULL
|| check_utility_compat("expr")) {
av = argv + 1;
nonposix = 1;
} else {
while ((c = getopt(argc, argv, "e")) != -1)
switch (c) {
case 'e':
nonposix = 1;
break;
default:
fprintf(stderr,
"usage: expr [-e] expression\n");
exit(ERR_EXIT);
}
av = argv + optind;
}
yyparse();
if (result->type == integer)
printf("%jd\n", result->u.i);
else
printf("%s\n", result->u.s);
return (is_zero_or_null(result));
}
int
yyerror(const char *s __unused)
{
errx(ERR_EXIT, "syntax error");
}
struct val *
op_or(struct val *a, struct val *b)
{
if (!is_zero_or_null(a)) {
free_value(b);
return (a);
}
free_value(a);
if (!is_zero_or_null(b))
return (b);
free_value(b);
return (make_integer((intmax_t)0));
}
struct val *
op_and(struct val *a, struct val *b)
{
if (is_zero_or_null (a) || is_zero_or_null (b)) {
free_value (a);
free_value (b);
return (make_integer ((intmax_t)0));
} else {
free_value (b);
return (a);
}
}
struct val *
op_eq(struct val *a, struct val *b)
{
struct val *r;
if (isstring (a) || isstring (b)) {
to_string (a);
to_string (b);
r = make_integer ((intmax_t)(strcoll (a->u.s, b->u.s) == 0));
} else {
assert_to_integer(a);
assert_to_integer(b);
r = make_integer ((intmax_t)(a->u.i == b->u.i));
}
free_value (a);
free_value (b);
return r;
}
struct val *
op_gt(struct val *a, struct val *b)
{
struct val *r;
if (isstring (a) || isstring (b)) {
to_string (a);
to_string (b);
r = make_integer ((intmax_t)(strcoll (a->u.s, b->u.s) > 0));
} else {
assert_to_integer(a);
assert_to_integer(b);
r = make_integer ((intmax_t)(a->u.i > b->u.i));
}
free_value (a);
free_value (b);
return r;
}
struct val *
op_lt(struct val *a, struct val *b)
{
struct val *r;
if (isstring (a) || isstring (b)) {
to_string (a);
to_string (b);
r = make_integer ((intmax_t)(strcoll (a->u.s, b->u.s) < 0));
} else {
assert_to_integer(a);
assert_to_integer(b);
r = make_integer ((intmax_t)(a->u.i < b->u.i));
}
free_value (a);
free_value (b);
return r;
}
struct val *
op_ge(struct val *a, struct val *b)
{
struct val *r;
if (isstring (a) || isstring (b)) {
to_string (a);
to_string (b);
r = make_integer ((intmax_t)(strcoll (a->u.s, b->u.s) >= 0));
} else {
assert_to_integer(a);
assert_to_integer(b);
r = make_integer ((intmax_t)(a->u.i >= b->u.i));
}
free_value (a);
free_value (b);
return r;
}
struct val *
op_le(struct val *a, struct val *b)
{
struct val *r;
if (isstring (a) || isstring (b)) {
to_string (a);
to_string (b);
r = make_integer ((intmax_t)(strcoll (a->u.s, b->u.s) <= 0));
} else {
assert_to_integer(a);
assert_to_integer(b);
r = make_integer ((intmax_t)(a->u.i <= b->u.i));
}
free_value (a);
free_value (b);
return r;
}
struct val *
op_ne(struct val *a, struct val *b)
{
struct val *r;
if (isstring (a) || isstring (b)) {
to_string (a);
to_string (b);
r = make_integer ((intmax_t)(strcoll (a->u.s, b->u.s) != 0));
} else {
assert_to_integer(a);
assert_to_integer(b);
r = make_integer ((intmax_t)(a->u.i != b->u.i));
}
free_value (a);
free_value (b);
return r;
}
int
chk_plus(intmax_t a, intmax_t b, intmax_t r)
{
/* sum of two positive numbers must be positive */
if (a > 0 && b > 0 && r <= 0)
return 1;
/* sum of two negative numbers must be negative */
if (a < 0 && b < 0 && r >= 0)
return 1;
/* all other cases are OK */
return 0;
}
struct val *
op_plus(struct val *a, struct val *b)
{
struct val *r;
assert_to_integer(a);
assert_to_integer(b);
r = make_integer(a->u.i + b->u.i);
if (chk_plus(a->u.i, b->u.i, r->u.i)) {
errx(ERR_EXIT, "overflow");
}
free_value (a);
free_value (b);
return r;
}
int
chk_minus(intmax_t a, intmax_t b, intmax_t r)
{
/* special case subtraction of INTMAX_MIN */
if (b == INTMAX_MIN) {
if (a >= 0)
return 1;
else
return 0;
}
/* this is allowed for b != INTMAX_MIN */
return chk_plus (a, -b, r);
}
struct val *
op_minus(struct val *a, struct val *b)
{
struct val *r;
assert_to_integer(a);
assert_to_integer(b);
r = make_integer(a->u.i - b->u.i);
if (chk_minus(a->u.i, b->u.i, r->u.i)) {
errx(ERR_EXIT, "overflow");
}
free_value (a);
free_value (b);
return r;
}
int
chk_times(intmax_t a, intmax_t b, intmax_t r)
{
/* special case: first operand is 0, no overflow possible */
if (a == 0)
return 0;
/* verify that result of division matches second operand */
if (r / a != b)
return 1;
return 0;
}
struct val *
op_times(struct val *a, struct val *b)
{
struct val *r;
assert_to_integer(a);
assert_to_integer(b);
r = make_integer(a->u.i * b->u.i);
if (chk_times(a->u.i, b->u.i, r->u.i)) {
errx(ERR_EXIT, "overflow");
}
free_value (a);
free_value (b);
return (r);
}
int
chk_div(intmax_t a, intmax_t b)
{
/* div by zero has been taken care of before */
/* only INTMAX_MIN / -1 causes overflow */
if (a == INTMAX_MIN && b == -1)
return 1;
/* everything else is OK */
return 0;
}
struct val *
op_div(struct val *a, struct val *b)
{
struct val *r;
assert_to_integer(a);
assert_to_integer(b);
if (b->u.i == 0) {
errx(ERR_EXIT, "division by zero");
}
if (chk_div(a->u.i, b->u.i)) {
errx(ERR_EXIT, "overflow");
}
r = make_integer(a->u.i / b->u.i);
free_value (a);
free_value (b);
return r;
}
struct val *
op_rem(struct val *a, struct val *b)
{
struct val *r;
assert_to_integer(a);
assert_to_integer(b);
if (b->u.i == 0) {
errx(ERR_EXIT, "division by zero");
}
r = make_integer(a->u.i % b->u.i);
free_value (a);
free_value (b);
return r;
}
struct val *
op_colon(struct val *a, struct val *b)
{
regex_t rp;
regmatch_t rm[2];
char errbuf[256];
int eval;
struct val *v;
/* coerce both arguments to strings */
to_string(a);
to_string(b);
/* compile regular expression */
if ((eval = regcomp (&rp, b->u.s, 0)) != 0) {
regerror (eval, &rp, errbuf, sizeof(errbuf));
errx(ERR_EXIT, "%s", errbuf);
}
/* compare string against pattern */
/* remember that patterns are anchored to the beginning of the line */
if (regexec(&rp, a->u.s, (size_t)2, rm, 0) == 0 && rm[0].rm_so == 0) {
if (rm[1].rm_so >= 0) {
*(a->u.s + rm[1].rm_eo) = '\0';
v = make_str (a->u.s + rm[1].rm_so);
} else {
v = make_integer ((intmax_t)(rm[0].rm_eo - rm[0].rm_so));
}
} else {
if (rp.re_nsub == 0) {
v = make_integer ((intmax_t)0);
} else {
v = make_str ("");
}
}
/* free arguments and pattern buffer */
free_value (a);
free_value (b);
regfree (&rp);
return v;
}
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