/* expr.c -- arithmetic expression evaluation. */
-/* Copyright (C) 1990-2004 Free Software Foundation, Inc.
+/* Copyright (C) 1990-2013 Free Software Foundation, Inc.
This file is part of GNU Bash, the Bourne Again SHell.
- Bash 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, or (at your option)
- any later version.
+ Bash 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 3 of the License, or
+ (at your option) any later version.
- Bash 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.
+ Bash 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 Bash; see the file COPYING. If not, write to the Free
- Software Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA. */
+ along with Bash. If not, see <http://www.gnu.org/licenses/>.
+*/
/*
All arithmetic is done as intmax_t integers with no checking for overflow
Implementation is a recursive-descent parser.
Chet Ramey
- chet@ins.CWRU.Edu
+ chet@po.cwru.edu
*/
#include "config.h"
#include "bashintl.h"
#include "shell.h"
+#include "typemax.h" /* INTMAX_MAX, INTMAX_MIN */
/* Because of the $((...)) construct, expressions may include newlines.
Here is a macro which accepts newlines, tabs and spaces as whitespace. */
#define cr_whitespace(c) (whitespace(c) || ((c) == '\n'))
-/* Size be which the expression stack grows when neccessary. */
+/* Size be which the expression stack grows when necessary. */
#define EXPR_STACK_GROW_SIZE 10
/* Maximum amount of recursion allowed. This prevents a non-integer
highest precedence. */
#define EXP_HIGHEST expcomma
+#ifndef MAX_INT_LEN
+# define MAX_INT_LEN 32
+#endif
+
+struct lvalue
+{
+ char *tokstr; /* possibly-rewritten lvalue if not NULL */
+ intmax_t tokval; /* expression evaluated value */
+ SHELL_VAR *tokvar; /* variable described by array or var reference */
+ intmax_t ind; /* array index if not -1 */
+};
+
+/* A structure defining a single expression context. */
+typedef struct {
+ int curtok, lasttok;
+ char *expression, *tp, *lasttp;
+ intmax_t tokval;
+ char *tokstr;
+ int noeval;
+ struct lvalue lval;
+} EXPR_CONTEXT;
+
static char *expression; /* The current expression */
static char *tp; /* token lexical position */
static char *lasttp; /* pointer to last token position */
static int noeval; /* set to 1 if no assignment to be done */
static procenv_t evalbuf;
+static struct lvalue curlval = {0, 0, 0, -1};
+static struct lvalue lastlval = {0, 0, 0, -1};
+
+static int _is_arithop __P((int));
static void readtok __P((void)); /* lexical analyzer */
-static intmax_t expr_streval __P((char *, int));
+static void init_lvalue __P((struct lvalue *));
+static struct lvalue *alloc_lvalue __P((void));
+static void free_lvalue __P((struct lvalue *));
+
+static intmax_t expr_streval __P((char *, int, struct lvalue *));
static intmax_t strlong __P((char *));
-static void evalerror __P((char *));
+static void evalerror __P((const char *));
static void pushexp __P((void));
static void popexp __P((void));
static void expr_unwind __P((void));
static void expr_bind_variable __P((char *, char *));
+#if defined (ARRAY_VARS)
+static void expr_bind_array_element __P((char *, arrayind_t, char *));
+#endif
static intmax_t subexpr __P((char *));
static intmax_t exp1 __P((void));
static intmax_t exp0 __P((void));
-/* A structure defining a single expression context. */
-typedef struct {
- int curtok, lasttok;
- char *expression, *tp, *lasttp;
- intmax_t tokval;
- char *tokstr;
- int noeval;
-} EXPR_CONTEXT;
-
-#ifdef INCLUDE_UNUSED
-/* Not used yet. */
-typedef struct {
- char *tokstr;
- intmax_t tokval;
-} LVALUE;
-#endif
-
/* Global var which contains the stack of expression contexts. */
static EXPR_CONTEXT **expr_stack;
static int expr_depth; /* Location in the stack. */
static int expr_stack_size; /* Number of slots already allocated. */
extern char *this_command_name;
-extern int unbound_vars_is_error;
+extern int unbound_vars_is_error, last_command_exit_value;
#if defined (ARRAY_VARS)
-extern char *bash_badsub_errmsg;
+extern const char * const bash_badsub_errmsg;
#endif
#define SAVETOK(X) \
(X)->tokval = tokval; \
(X)->tokstr = tokstr; \
(X)->noeval = noeval; \
+ (X)->lval = curlval; \
} while (0)
#define RESTORETOK(X) \
tokval = (X)->tokval; \
tokstr = (X)->tokstr; \
noeval = (X)->noeval; \
+ curlval = (X)->lval; \
} while (0)
/* Push and save away the contents of the globals describing the
free (expr_stack[expr_depth]);
}
free (expr_stack[expr_depth]); /* free the allocated EXPR_CONTEXT */
+
+ noeval = 0; /* XXX */
}
static void
expr_bind_variable (lhs, rhs)
char *lhs, *rhs;
{
- (void)bind_int_variable (lhs, rhs);
+ SHELL_VAR *v;
+
+ v = bind_int_variable (lhs, rhs);
+ if (v && (readonly_p (v) || noassign_p (v)))
+ longjmp (evalbuf, 1); /* variable assignment error */
stupidly_hack_special_variables (lhs);
}
+#if defined (ARRAY_VARS)
+/* Rewrite tok, which is of the form vname[expression], to vname[ind], where
+ IND is the already-calculated value of expression. */
+static void
+expr_bind_array_element (tok, ind, rhs)
+ char *tok;
+ arrayind_t ind;
+ char *rhs;
+{
+ char *lhs, *vname;
+ size_t llen;
+ char ibuf[INT_STRLEN_BOUND (arrayind_t) + 1], *istr;
+
+ istr = fmtumax (ind, 10, ibuf, sizeof (ibuf), 0);
+ vname = array_variable_name (tok, (char **)NULL, (int *)NULL);
+
+ llen = strlen (vname) + sizeof (ibuf) + 3;
+ lhs = xmalloc (llen);
+
+ sprintf (lhs, "%s[%s]", vname, istr); /* XXX */
+
+/*itrace("expr_bind_array_element: %s=%s", lhs, rhs);*/
+ expr_bind_variable (lhs, rhs);
+ free (vname);
+ free (lhs);
+}
+#endif /* ARRAY_VARS */
+
/* Evaluate EXPR, and return the arithmetic result. If VALIDP is
non-null, a zero is stored into the location to which it points
if the expression is invalid, non-zero otherwise. If a non-zero
procenv_t oevalbuf;
val = 0;
+ noeval = 0;
FASTCOPY (evalbuf, oevalbuf, sizeof (evalbuf));
- c = setjmp (evalbuf);
+ c = setjmp_nosigs (evalbuf);
if (c)
{
return (0);
pushexp ();
- curtok = lasttok = 0;
expression = savestring (expr);
tp = expression;
+ curtok = lasttok = 0;
tokstr = (char *)NULL;
tokval = 0;
+ init_lvalue (&curlval);
+ lastlval = curlval;
readtok ();
{
register intmax_t value;
char *lhs, *rhs;
+ arrayind_t lind;
+#if defined (HAVE_IMAXDIV)
+ imaxdiv_t idiv;
+#endif
value = expcond ();
if (curtok == EQ || curtok == OP_ASSIGN)
lvalue = value;
}
+ /* XXX - watch out for pointer aliasing issues here */
lhs = savestring (tokstr);
+ /* save ind in case rhs is string var and evaluation overwrites it */
+ lind = curlval.ind;
readtok ();
value = expassign ();
if (special)
{
+ if ((op == DIV || op == MOD) && value == 0)
+ {
+ if (noeval == 0)
+ evalerror (_("division by 0"));
+ else
+ value = 1;
+ }
+
switch (op)
{
case MUL:
lvalue *= value;
break;
case DIV:
- if (value == 0)
- evalerror (_("division by 0"));
- lvalue /= value;
- break;
case MOD:
- if (value == 0)
- evalerror (_("division by 0"));
- lvalue %= value;
+ if (lvalue == INTMAX_MIN && value == -1)
+ lvalue = (op == DIV) ? INTMAX_MIN : 0;
+ else
+#if HAVE_IMAXDIV
+ {
+ idiv = imaxdiv (lvalue, value);
+ lvalue = (op == DIV) ? idiv.quot : idiv.rem;
+ }
+#else
+ lvalue = (op == DIV) ? lvalue / value : lvalue % value;
+#endif
break;
case PLUS:
lvalue += value;
rhs = itos (value);
if (noeval == 0)
- expr_bind_variable (lhs, rhs);
+ {
+#if defined (ARRAY_VARS)
+ if (lind != -1)
+ expr_bind_array_element (lhs, lind, rhs);
+ else
+#endif
+ expr_bind_variable (lhs, rhs);
+ }
+ if (curlval.tokstr && curlval.tokstr == tokstr)
+ init_lvalue (&curlval);
+
free (rhs);
free (lhs);
FREE (tokstr);
tokstr = (char *)NULL; /* For freeing on errors. */
}
+
return (value);
}
set_noeval = 1;
noeval++;
}
- val2 = explor ();
+
+ val2 = expcond ();
if (set_noeval)
noeval--;
rval = cval ? val1 : val2;
readtok ();
val2 = expbxor ();
val1 = val1 | val2;
+ lasttok = NUM;
}
return (val1);
readtok ();
val2 = expband ();
val1 = val1 ^ val2;
+ lasttok = NUM;
}
return (val1);
readtok ();
val2 = exp5 ();
val1 = val1 & val2;
+ lasttok = NUM;
}
return (val1);
val1 = (val1 == val2);
else if (op == NEQ)
val1 = (val1 != val2);
+ lasttok = NUM;
}
return (val1);
}
val1 = val1 < val2;
else /* (op == GT) */
val1 = val1 > val2;
+ lasttok = NUM;
}
return (val1);
}
val1 = val1 << val2;
else
val1 = val1 >> val2;
+ lasttok = NUM;
}
return (val1);
val1 += val2;
else if (op == MINUS)
val1 -= val2;
+ lasttok = NUM;
}
return (val1);
}
exp2 ()
{
register intmax_t val1, val2;
+#if defined (HAVE_IMAXDIV)
+ imaxdiv_t idiv;
+#endif
val1 = exppower ();
(curtok == MOD))
{
int op = curtok;
+ char *stp, *sltp;
+ stp = tp;
readtok ();
val2 = exppower ();
+ /* Handle division by 0 and twos-complement arithmetic overflow */
if (((op == DIV) || (op == MOD)) && (val2 == 0))
- evalerror (_("division by 0"));
+ {
+ if (noeval == 0)
+ {
+ sltp = lasttp;
+ lasttp = stp;
+ while (lasttp && *lasttp && whitespace (*lasttp))
+ lasttp++;
+ evalerror (_("division by 0"));
+ lasttp = sltp;
+ }
+ else
+ val2 = 1;
+ }
+ else if (op == MOD && val1 == INTMAX_MIN && val2 == -1)
+ {
+ val1 = 0;
+ continue;
+ }
+ else if (op == DIV && val1 == INTMAX_MIN && val2 == -1)
+ val2 = 1;
if (op == MUL)
val1 *= val2;
- else if (op == DIV)
- val1 /= val2;
- else if (op == MOD)
- val1 %= val2;
+ else if (op == DIV || op == MOD)
+#if defined (HAVE_IMAXDIV)
+ {
+ idiv = imaxdiv (val1, val2);
+ val1 = (op == DIV) ? idiv.quot : idiv.rem;
+ }
+#else
+ val1 = (op == DIV) ? val1 / val2 : val1 % val2;
+#endif
+ lasttok = NUM;
}
return (val1);
}
static intmax_t
+ipow (base, exp)
+ intmax_t base, exp;
+{
+ intmax_t result;
+
+ result = 1;
+ while (exp)
+ {
+ if (exp & 1)
+ result *= base;
+ exp >>= 1;
+ base *= base;
+ }
+ return result;
+}
+
+static intmax_t
exppower ()
{
register intmax_t val1, val2, c;
{
readtok ();
val2 = exppower (); /* exponentiation is right-associative */
+ lasttok = NUM;
if (val2 == 0)
return (1);
if (val2 < 0)
evalerror (_("exponent less than 0"));
- for (c = 1; val2--; c *= val1)
- ;
- val1 = c;
+ val1 = ipow (val1, val2);
}
return (val1);
}
{
readtok ();
val = !exp1 ();
+ lasttok = NUM;
}
else if (curtok == BNOT)
{
readtok ();
val = ~exp1 ();
+ lasttok = NUM;
+ }
+ else if (curtok == MINUS)
+ {
+ readtok ();
+ val = - exp1 ();
+ lasttok = NUM;
+ }
+ else if (curtok == PLUS)
+ {
+ readtok ();
+ val = exp1 ();
+ lasttok = NUM;
}
else
val = exp0 ();
v2 = tokval + ((stok == PREINC) ? 1 : -1);
vincdec = itos (v2);
if (noeval == 0)
- expr_bind_variable (tokstr, vincdec);
+ {
+#if defined (ARRAY_VARS)
+ if (curlval.ind != -1)
+ expr_bind_array_element (curlval.tokstr, curlval.ind, vincdec);
+ else
+#endif
+ expr_bind_variable (tokstr, vincdec);
+ }
free (vincdec);
val = v2;
curtok = NUM; /* make sure --x=7 is flagged as an error */
readtok ();
}
- else if (curtok == MINUS)
- {
- readtok ();
- val = - exp0 ();
- }
- else if (curtok == PLUS)
- {
- readtok ();
- val = exp0 ();
- }
else if (curtok == LPAR)
{
+ /* XXX - save curlval here? Or entire expression context? */
readtok ();
val = EXP_HIGHEST ();
/* restore certain portions of EC */
tokstr = ec.tokstr;
noeval = ec.noeval;
+ curlval = ec.lval;
lasttok = STR; /* ec.curtok */
v2 = val + ((stok == POSTINC) ? 1 : -1);
vincdec = itos (v2);
if (noeval == 0)
- expr_bind_variable (tokstr, vincdec);
+ {
+#if defined (ARRAY_VARS)
+ if (curlval.ind != -1)
+ expr_bind_array_element (curlval.tokstr, curlval.ind, vincdec);
+ else
+#endif
+ expr_bind_variable (tokstr, vincdec);
+ }
free (vincdec);
curtok = NUM; /* make sure x++=7 is flagged as an error */
}
else
{
+ /* XXX - watch out for pointer aliasing issues here */
if (stok == STR) /* free new tokstr before old one is restored */
FREE (tokstr);
RESTORETOK (&ec);
}
-
}
readtok ();
return (val);
}
+static void
+init_lvalue (lv)
+ struct lvalue *lv;
+{
+ lv->tokstr = 0;
+ lv->tokvar = 0;
+ lv->tokval = lv->ind = -1;
+}
+
+static struct lvalue *
+alloc_lvalue ()
+{
+ struct lvalue *lv;
+
+ lv = xmalloc (sizeof (struct lvalue));
+ init_lvalue (lv);
+ return (lv);
+}
+
+static void
+free_lvalue (lv)
+ struct lvalue *lv;
+{
+ free (lv); /* should be inlined */
+}
+
static intmax_t
-expr_streval (tok, e)
+expr_streval (tok, e, lvalue)
char *tok;
int e;
+ struct lvalue *lvalue;
{
SHELL_VAR *v;
char *value;
intmax_t tval;
+#if defined (ARRAY_VARS)
+ arrayind_t ind;
+#endif
+
+/*itrace("expr_streval: %s: noeval = %d", tok, noeval);*/
+ /* If we are suppressing evaluation, just short-circuit here instead of
+ going through the rest of the evaluator. */
+ if (noeval)
+ return (0);
/* [[[[[ */
#if defined (ARRAY_VARS)
value = tok;
#endif
+ last_command_exit_value = EXECUTION_FAILURE;
err_unboundvar (value);
#if defined (ARRAY_VARS)
if (interactive_shell)
{
expr_unwind ();
+ top_level_cleanup ();
jump_to_top_level (DISCARD);
}
else
}
#if defined (ARRAY_VARS)
+ ind = -1;
/* Second argument of 0 to get_array_value means that we don't allow
references like array[@]. In this case, get_array_value is just
like get_variable_value in that it does not return newly-allocated
memory or quote the results. */
- value = (e == ']') ? get_array_value (tok, 0, (int *)NULL) : get_variable_value (v);
+ value = (e == ']') ? get_array_value (tok, 0, (int *)NULL, &ind) : get_variable_value (v);
#else
value = get_variable_value (v);
#endif
tval = (value && *value) ? subexpr (value) : 0;
+ if (lvalue)
+ {
+ lvalue->tokstr = tok; /* XXX */
+ lvalue->tokval = tval;
+ lvalue->tokvar = v; /* XXX */
+#if defined (ARRAY_VARS)
+ lvalue->ind = ind;
+#else
+ lvalue->ind = -1;
+#endif
+ }
+
return (tval);
}
+static int
+_is_multiop (c)
+ int c;
+{
+ switch (c)
+ {
+ case EQEQ:
+ case NEQ:
+ case LEQ:
+ case GEQ:
+ case LAND:
+ case LOR:
+ case LSH:
+ case RSH:
+ case OP_ASSIGN:
+ case COND:
+ case POWER:
+ case PREINC:
+ case PREDEC:
+ case POSTINC:
+ case POSTDEC:
+ return 1;
+ default:
+ return 0;
+ }
+}
+
+static int
+_is_arithop (c)
+ int c;
+{
+ switch (c)
+ {
+ case EQ:
+ case GT:
+ case LT:
+ case PLUS:
+ case MINUS:
+ case MUL:
+ case DIV:
+ case MOD:
+ case NOT:
+ case LPAR:
+ case RPAR:
+ case BAND:
+ case BOR:
+ case BXOR:
+ case BNOT:
+ return 1; /* operator tokens */
+ case QUES:
+ case COL:
+ case COMMA:
+ return 1; /* questionable */
+ default:
+ return 0; /* anything else is invalid */
+ }
+}
+
/* Lexical analyzer/token reader for the expression evaluator. Reads the
next token and puts its value into curtok, while advancing past it.
Updates value of tp. May also set tokval (for number) or tokstr (for
register char *cp, *xp;
register unsigned char c, c1;
register int e;
+ struct lvalue lval;
/* Skip leading whitespace. */
cp = tp;
if (c)
cp++;
- lasttp = tp = cp - 1;
-
if (c == '\0')
{
lasttok = curtok;
tp = cp;
return;
}
+ lasttp = tp = cp - 1;
if (legal_variable_starter (c))
{
#if defined (ARRAY_VARS)
if (c == '[')
{
- e = skipsubscript (cp, 0);
+ e = skipsubscript (cp, 0, 0);
if (cp[e] == ']')
{
cp += e + 1;
#endif /* ARRAY_VARS */
*cp = '\0';
+ /* XXX - watch out for pointer aliasing issues here */
+ if (curlval.tokstr && curlval.tokstr == tokstr)
+ init_lvalue (&curlval);
+
FREE (tokstr);
tokstr = savestring (tp);
*cp = c;
+ /* XXX - make peektok part of saved token state? */
SAVETOK (&ec);
tokstr = (char *)NULL; /* keep it from being freed */
tp = savecp = cp;
/* The tests for PREINC and PREDEC aren't strictly correct, but they
preserve old behavior if a construct like --x=9 is given. */
if (lasttok == PREINC || lasttok == PREDEC || peektok != EQ)
- tokval = expr_streval (tokstr, e);
+ {
+ lastlval = curlval;
+ tokval = expr_streval (tokstr, e, &curlval);
+ }
else
tokval = 0;
assigntok = c; /* a OP= b */
c = OP_ASSIGN;
}
+ else if (_is_arithop (c) == 0)
+ {
+ cp--;
+ /* use curtok, since it hasn't been copied to lasttok yet */
+ if (curtok == 0 || _is_arithop (curtok) || _is_multiop (curtok))
+ evalerror (_("syntax error: operand expected"));
+ else
+ evalerror (_("syntax error: invalid arithmetic operator"));
+ }
else
cp--; /* `unget' the character */
+
+ /* Should check here to make sure that the current character is one
+ of the recognized operators and flag an error if not. Could create
+ a character map the first time through and check it on subsequent
+ calls. */
lasttok = curtok;
curtok = c;
}
static void
evalerror (msg)
- char *msg;
+ const char *msg;
{
char *name, *t;
name = this_command_name;
for (t = expression; whitespace (*t); t++)
;
- internal_error ("%s%s%s: %s (error token is \"%s\")",
+ internal_error (_("%s%s%s: %s (error token is \"%s\")"),
name ? name : "", name ? ": " : "", t,
msg, (lasttp && *lasttp) ? lasttp : "");
longjmp (evalbuf, 1);
{
v = evalexp (argv[i], &expok);
if (expok == 0)
- fprintf (stderr, "%s: expression error\n", argv[i]);
+ fprintf (stderr, _("%s: expression error\n"), argv[i]);
else
printf ("'%s' -> %ld\n", argv[i], v);
}
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