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split math code out of ash and into a standalone library so we can use it in any shell (like hush!)

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This commit is contained in:
Mike Frysinger 2009-04-02 10:02:37 +00:00
parent 551ffdccea
commit 98c52645c0
6 changed files with 945 additions and 726 deletions
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32
shell/Config.in
View File

@ -84,22 +84,6 @@ config ASH_ALIAS
help
Enable alias support in the ash shell.
config ASH_MATH_SUPPORT
bool "Posix math support"
default y
depends on ASH
help
Enable math support in the ash shell.
config ASH_MATH_SUPPORT_64
bool "Extend Posix math support to 64 bit"
default n
depends on ASH_MATH_SUPPORT
help
Enable 64-bit math support in the ash shell. This will make
the shell slightly larger, but will allow computation with very
large numbers.
config ASH_GETOPTS
bool "Builtin getopt to parse positional parameters"
default n
@ -267,6 +251,22 @@ config MSH
comment "Bourne Shell Options"
depends on MSH || LASH || HUSH || ASH
config SH_MATH_SUPPORT
bool "POSIX math support"
default y
depends on ASH || HUSH
help
Enable math support in the shell via $((...)) syntax.
config SH_MATH_SUPPORT_64
bool "Extend POSIX math support to 64 bit"
default n
depends on SH_MATH_SUPPORT
help
Enable 64-bit math support in the shell. This will make the shell
slightly larger, but will allow computation with very large numbers.
This is not in POSIX, so do not rely on this in portable code.
config FEATURE_SH_EXTRA_QUIET
bool "Hide message on interactive shell startup"
default n

1
shell/Kbuild
View File

@ -9,3 +9,4 @@ lib-$(CONFIG_ASH) += ash.o ash_ptr_hack.o
lib-$(CONFIG_HUSH) += hush.o
lib-$(CONFIG_MSH) += msh.o
lib-$(CONFIG_CTTYHACK) += cttyhack.o
lib-$(CONFIG_SH_MATH_SUPPORT) += math.o

734
shell/ash.c
View File

@ -16,19 +16,6 @@
* Original BSD copyright notice is retained at the end of this file.
*/
/*
* rewrite arith.y to micro stack based cryptic algorithm by
* Copyright (c) 2001 Aaron Lehmann <aaronl@vitelus.com>
*
* Modified by Paul Mundt <lethal@linux-sh.org> (c) 2004 to support
* dynamic variables.
*
* Modified by Vladimir Oleynik <dzo@simtreas.ru> (c) 2001-2005 to be
* used in busybox and size optimizations,
* rewrote arith (see notes to this), added locale support,
* rewrote dynamic variables.
*/
/*
* The following should be set to reflect the type of system you have:
* JOBS -> 1 if you have Berkeley job control, 0 otherwise.
@ -63,6 +50,7 @@
#include <paths.h>
#include <setjmp.h>
#include <fnmatch.h>
#include "math.h"
#if defined SINGLE_APPLET_MAIN
/* STANDALONE does not make sense, and won't compile */
@ -197,6 +185,10 @@ struct globals_misc {
#define debug optlist[15]
#endif
#if ENABLE_SH_MATH_SUPPORT
arith_eval_hooks_t math_hooks;
#endif
/* trap handler commands */
/*
* Sigmode records the current value of the signal handlers for the various
@ -246,6 +238,7 @@ extern struct globals_misc *const ash_ptr_to_globals_misc;
#define random_LCG (G_misc.random_LCG )
#define backgndpid (G_misc.backgndpid )
#define job_warning (G_misc.job_warning)
#define math_hooks (G_misc.math_hooks )
#define INIT_G_misc() do { \
(*(struct globals_misc**)&ash_ptr_to_globals_misc) = xzalloc(sizeof(G_misc)); \
barrier(); \
@ -1998,7 +1991,7 @@ findvar(struct var **vpp, const char *name)
/*
* Find the value of a variable. Returns NULL if not set.
*/
static char *
static const char *
lookupvar(const char *name)
{
struct var *v;
@ -2024,7 +2017,7 @@ lookupvar(const char *name)
/*
* Search the environment of a builtin command.
*/
static char *
static const char *
bltinlookup(const char *name)
{
struct strlist *sp;
@ -2637,7 +2630,7 @@ pwdcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
#define USE_SIT_FUNCTION
#endif
#if ENABLE_ASH_MATH_SUPPORT
#if ENABLE_SH_MATH_SUPPORT
static const char S_I_T[][4] = {
#if ENABLE_ASH_ALIAS
{ CSPCL, CIGN, CIGN, CIGN }, /* 0, PEOA */
@ -2681,7 +2674,7 @@ static const char S_I_T[][3] = {
{ CCTL, CCTL, CCTL } /* 14, CTLESC ... */
#endif
};
#endif /* ASH_MATH_SUPPORT */
#endif /* SH_MATH_SUPPORT */
#ifdef USE_SIT_FUNCTION
@ -4273,7 +4266,7 @@ cmdputs(const char *s)
case CTLBACKQ+CTLQUOTE:
str = "\"$(...)\"";
goto dostr;
#if ENABLE_ASH_MATH_SUPPORT
#if ENABLE_SH_MATH_SUPPORT
case CTLARI:
str = "$((";
goto dostr;
@ -5258,17 +5251,8 @@ redirectsafe(union node *redir, int flags)
* We have to deal with backquotes, shell variables, and file metacharacters.
*/
#if ENABLE_ASH_MATH_SUPPORT_64
typedef int64_t arith_t;
#define arith_t_type long long
#else
typedef long arith_t;
#define arith_t_type long
#endif
#if ENABLE_ASH_MATH_SUPPORT
#if ENABLE_SH_MATH_SUPPORT
static arith_t dash_arith(const char *);
static arith_t arith(const char *expr, int *perrcode);
#endif
/*
@ -5328,11 +5312,7 @@ cvtnum(arith_t num)
int len;
expdest = makestrspace(32, expdest);
#if ENABLE_ASH_MATH_SUPPORT_64
len = fmtstr(expdest, 32, "%lld", (long long) num);
#else
len = fmtstr(expdest, 32, "%ld", num);
#endif
len = fmtstr(expdest, 32, arith_t_fmt, num);
STADJUST(len, expdest);
return len;
}
@ -5696,7 +5676,7 @@ expbackq(union node *cmd, int quoted, int quotes)
stackblock() + startloc));
}
#if ENABLE_ASH_MATH_SUPPORT
#if ENABLE_SH_MATH_SUPPORT
/*
* Expand arithmetic expression. Backup to start of expression,
* evaluate, place result in (backed up) result, adjust string position.
@ -5782,7 +5762,7 @@ argstr(char *p, int flag, struct strlist *var_str_list)
CTLVAR,
CTLBACKQ,
CTLBACKQ | CTLQUOTE,
#if ENABLE_ASH_MATH_SUPPORT
#if ENABLE_SH_MATH_SUPPORT
CTLENDARI,
#endif
0
@ -5819,7 +5799,7 @@ argstr(char *p, int flag, struct strlist *var_str_list)
length += strcspn(p + length, reject);
c = p[length];
if (c && (!(c & 0x80)
#if ENABLE_ASH_MATH_SUPPORT
#if ENABLE_SH_MATH_SUPPORT
|| c == CTLENDARI
#endif
)) {
@ -5897,7 +5877,7 @@ argstr(char *p, int flag, struct strlist *var_str_list)
expbackq(argbackq->n, c, quotes);
argbackq = argbackq->next;
goto start;
#if ENABLE_ASH_MATH_SUPPORT
#if ENABLE_SH_MATH_SUPPORT
case CTLENDARI:
p--;
expari(quotes);
@ -6291,7 +6271,7 @@ static ssize_t
varvalue(char *name, int varflags, int flags, struct strlist *var_str_list)
{
int num;
char *p;
const char *p;
int i;
int sep = 0;
int sepq = 0;
@ -6324,14 +6304,13 @@ varvalue(char *name, int varflags, int flags, struct strlist *var_str_list)
len = cvtnum(num);
break;
case '-':
p = makestrspace(NOPTS, expdest);
expdest = makestrspace(NOPTS, expdest);
for (i = NOPTS - 1; i >= 0; i--) {
if (optlist[i]) {
USTPUTC(optletters(i), p);
USTPUTC(optletters(i), expdest);
len++;
}
}
expdest = p;
break;
case '@':
if (sep)
@ -8710,7 +8689,7 @@ static int getoptscmd(int, char **);
#if !ENABLE_FEATURE_SH_EXTRA_QUIET
static int helpcmd(int, char **);
#endif
#if ENABLE_ASH_MATH_SUPPORT
#if ENABLE_SH_MATH_SUPPORT
static int letcmd(int, char **);
#endif
static int readcmd(int, char **);
@ -8792,7 +8771,7 @@ static const struct builtincmd builtintab[] = {
{ BUILTIN_REGULAR "jobs", jobscmd },
{ BUILTIN_REGULAR "kill", killcmd },
#endif
#if ENABLE_ASH_MATH_SUPPORT
#if ENABLE_SH_MATH_SUPPORT
{ BUILTIN_NOSPEC "let", letcmd },
#endif
{ BUILTIN_ASSIGN "local", localcmd },
@ -10935,7 +10914,7 @@ readtoken1(int firstc, int syntax, char *eofmark, int striptabs)
USTPUTC(c, out);
}
break;
#if ENABLE_ASH_MATH_SUPPORT
#if ENABLE_SH_MATH_SUPPORT
case CLP: /* '(' in arithmetic */
parenlevel++;
USTPUTC(c, out);
@ -10991,7 +10970,7 @@ readtoken1(int firstc, int syntax, char *eofmark, int striptabs)
} /* for (;;) */
}
endword:
#if ENABLE_ASH_MATH_SUPPORT
#if ENABLE_SH_MATH_SUPPORT
if (syntax == ARISYNTAX)
raise_error_syntax("missing '))'");
#endif
@ -11168,7 +11147,7 @@ parsesub: {
pungetc();
} else if (c == '(') { /* $(command) or $((arith)) */
if (pgetc() == '(') {
#if ENABLE_ASH_MATH_SUPPORT
#if ENABLE_SH_MATH_SUPPORT
PARSEARITH();
#else
raise_error_syntax("you disabled math support for $((arith)) syntax");
@ -11423,7 +11402,7 @@ parsebackq: {
goto parsebackq_newreturn;
}
#if ENABLE_ASH_MATH_SUPPORT
#if ENABLE_SH_MATH_SUPPORT
/*
* Parse an arithmetic expansion (indicate start of one and set state)
*/
@ -12384,7 +12363,7 @@ timescmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
return 0;
}
#if ENABLE_ASH_MATH_SUPPORT
#if ENABLE_SH_MATH_SUPPORT
static arith_t
dash_arith(const char *s)
{
@ -12392,7 +12371,7 @@ dash_arith(const char *s)
int errcode = 0;
INT_OFF;
result = arith(s, &errcode);
result = arith(s, &errcode, &math_hooks);
if (errcode < 0) {
if (errcode == -3)
ash_msg_and_raise_error("exponent less than 0");
@ -12427,7 +12406,7 @@ letcmd(int argc UNUSED_PARAM, char **argv)
return !i;
}
#endif /* ASH_MATH_SUPPORT */
#endif /* SH_MATH_SUPPORT */
/* ============ miscbltin.c
@ -12951,654 +12930,6 @@ ulimitcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
return 0;
}
/* ============ Math support */
#if ENABLE_ASH_MATH_SUPPORT
/* Copyright (c) 2001 Aaron Lehmann <aaronl@vitelus.com>
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:
The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
/* This is my infix parser/evaluator. It is optimized for size, intended
* as a replacement for yacc-based parsers. However, it may well be faster
* than a comparable parser written in yacc. The supported operators are
* listed in #defines below. Parens, order of operations, and error handling
* are supported. This code is thread safe. The exact expression format should
* be that which POSIX specifies for shells. */
/* The code uses a simple two-stack algorithm. See
* http://www.onthenet.com.au/~grahamis/int2008/week02/lect02.html
* for a detailed explanation of the infix-to-postfix algorithm on which
* this is based (this code differs in that it applies operators immediately
* to the stack instead of adding them to a queue to end up with an
* expression). */
/* To use the routine, call it with an expression string and error return
* pointer */
/*
* Aug 24, 2001 Manuel Novoa III
*
* Reduced the generated code size by about 30% (i386) and fixed several bugs.
*
* 1) In arith_apply():
* a) Cached values of *numptr and &(numptr[-1]).
* b) Removed redundant test for zero denominator.
*
* 2) In arith():
* a) Eliminated redundant code for processing operator tokens by moving
* to a table-based implementation. Also folded handling of parens
* into the table.
* b) Combined all 3 loops which called arith_apply to reduce generated
* code size at the cost of speed.
*
* 3) The following expressions were treated as valid by the original code:
* 1() , 0! , 1 ( *3 ) .
* These bugs have been fixed by internally enclosing the expression in
* parens and then checking that all binary ops and right parens are
* preceded by a valid expression (NUM_TOKEN).
*
* Note: It may be desirable to replace Aaron's test for whitespace with
* ctype's isspace() if it is used by another busybox applet or if additional
* whitespace chars should be considered. Look below the "#include"s for a
* precompiler test.
*/
/*
* Aug 26, 2001 Manuel Novoa III
*
* Return 0 for null expressions. Pointed out by Vladimir Oleynik.
*
* Merge in Aaron's comments previously posted to the busybox list,
* modified slightly to take account of my changes to the code.
*
*/
/*
* (C) 2003 Vladimir Oleynik <dzo@simtreas.ru>
*
* - allow access to variable,
* used recursive find value indirection (c=2*2; a="c"; $((a+=2)) produce 6)
* - realize assign syntax (VAR=expr, +=, *= etc)
* - realize exponentiation (** operator)
* - realize comma separated - expr, expr
* - realise ++expr --expr expr++ expr--
* - realise expr ? expr : expr (but, second expr calculate always)
* - allow hexadecimal and octal numbers
* - was restored loses XOR operator
* - remove one goto label, added three ;-)
* - protect $((num num)) as true zero expr (Manuel`s error)
* - always use special isspace(), see comment from bash ;-)
*/
#define arith_isspace(arithval) \
(arithval == ' ' || arithval == '\n' || arithval == '\t')
typedef unsigned char operator;
/* An operator's token id is a bit of a bitfield. The lower 5 bits are the
* precedence, and 3 high bits are an ID unique across operators of that
* precedence. The ID portion is so that multiple operators can have the
* same precedence, ensuring that the leftmost one is evaluated first.
* Consider * and /. */
#define tok_decl(prec,id) (((id)<<5)|(prec))
#define PREC(op) ((op) & 0x1F)
#define TOK_LPAREN tok_decl(0,0)
#define TOK_COMMA tok_decl(1,0)
#define TOK_ASSIGN tok_decl(2,0)
#define TOK_AND_ASSIGN tok_decl(2,1)
#define TOK_OR_ASSIGN tok_decl(2,2)
#define TOK_XOR_ASSIGN tok_decl(2,3)
#define TOK_PLUS_ASSIGN tok_decl(2,4)
#define TOK_MINUS_ASSIGN tok_decl(2,5)
#define TOK_LSHIFT_ASSIGN tok_decl(2,6)
#define TOK_RSHIFT_ASSIGN tok_decl(2,7)
#define TOK_MUL_ASSIGN tok_decl(3,0)
#define TOK_DIV_ASSIGN tok_decl(3,1)
#define TOK_REM_ASSIGN tok_decl(3,2)
/* all assign is right associativity and precedence eq, but (7+3)<<5 > 256 */
#define convert_prec_is_assing(prec) do { if (prec == 3) prec = 2; } while (0)
/* conditional is right associativity too */
#define TOK_CONDITIONAL tok_decl(4,0)
#define TOK_CONDITIONAL_SEP tok_decl(4,1)
#define TOK_OR tok_decl(5,0)
#define TOK_AND tok_decl(6,0)
#define TOK_BOR tok_decl(7,0)
#define TOK_BXOR tok_decl(8,0)
#define TOK_BAND tok_decl(9,0)
#define TOK_EQ tok_decl(10,0)
#define TOK_NE tok_decl(10,1)
#define TOK_LT tok_decl(11,0)
#define TOK_GT tok_decl(11,1)
#define TOK_GE tok_decl(11,2)
#define TOK_LE tok_decl(11,3)
#define TOK_LSHIFT tok_decl(12,0)
#define TOK_RSHIFT tok_decl(12,1)
#define TOK_ADD tok_decl(13,0)
#define TOK_SUB tok_decl(13,1)
#define TOK_MUL tok_decl(14,0)
#define TOK_DIV tok_decl(14,1)
#define TOK_REM tok_decl(14,2)
/* exponent is right associativity */
#define TOK_EXPONENT tok_decl(15,1)
/* For now unary operators. */
#define UNARYPREC 16
#define TOK_BNOT tok_decl(UNARYPREC,0)
#define TOK_NOT tok_decl(UNARYPREC,1)
#define TOK_UMINUS tok_decl(UNARYPREC+1,0)
#define TOK_UPLUS tok_decl(UNARYPREC+1,1)
#define PREC_PRE (UNARYPREC+2)
#define TOK_PRE_INC tok_decl(PREC_PRE, 0)
#define TOK_PRE_DEC tok_decl(PREC_PRE, 1)
#define PREC_POST (UNARYPREC+3)
#define TOK_POST_INC tok_decl(PREC_POST, 0)
#define TOK_POST_DEC tok_decl(PREC_POST, 1)
#define SPEC_PREC (UNARYPREC+4)
#define TOK_NUM tok_decl(SPEC_PREC, 0)
#define TOK_RPAREN tok_decl(SPEC_PREC, 1)
#define NUMPTR (*numstackptr)
static int
tok_have_assign(operator op)
{
operator prec = PREC(op);
convert_prec_is_assing(prec);
return (prec == PREC(TOK_ASSIGN) ||
prec == PREC_PRE || prec == PREC_POST);
}
static int
is_right_associativity(operator prec)
{
return (prec == PREC(TOK_ASSIGN) || prec == PREC(TOK_EXPONENT)
|| prec == PREC(TOK_CONDITIONAL));
}
typedef struct {
arith_t val;
arith_t contidional_second_val;
char contidional_second_val_initialized;
char *var; /* if NULL then is regular number,
else is variable name */
} v_n_t;
typedef struct chk_var_recursive_looped_t {
const char *var;
struct chk_var_recursive_looped_t *next;
} chk_var_recursive_looped_t;
static chk_var_recursive_looped_t *prev_chk_var_recursive;
static int
arith_lookup_val(v_n_t *t)
{
if (t->var) {
const char * p = lookupvar(t->var);
if (p) {
int errcode;
/* recursive try as expression */
chk_var_recursive_looped_t *cur;
chk_var_recursive_looped_t cur_save;
for (cur = prev_chk_var_recursive; cur; cur = cur->next) {
if (strcmp(cur->var, t->var) == 0) {
/* expression recursion loop detected */
return -5;
}
}
/* save current lookuped var name */
cur = prev_chk_var_recursive;
cur_save.var = t->var;
cur_save.next = cur;
prev_chk_var_recursive = &cur_save;
t->val = arith (p, &errcode);
/* restore previous ptr after recursiving */
prev_chk_var_recursive = cur;
return errcode;
}
/* allow undefined var as 0 */
t->val = 0;
}
return 0;
}
/* "applying" a token means performing it on the top elements on the integer
* stack. For a unary operator it will only change the top element, but a
* binary operator will pop two arguments and push a result */
static int
arith_apply(operator op, v_n_t *numstack, v_n_t **numstackptr)
{
v_n_t *numptr_m1;
arith_t numptr_val, rez;
int ret_arith_lookup_val;
/* There is no operator that can work without arguments */
if (NUMPTR == numstack) goto err;
numptr_m1 = NUMPTR - 1;
/* check operand is var with noninteger value */
ret_arith_lookup_val = arith_lookup_val(numptr_m1);
if (ret_arith_lookup_val)
return ret_arith_lookup_val;
rez = numptr_m1->val;
if (op == TOK_UMINUS)
rez *= -1;
else if (op == TOK_NOT)
rez = !rez;
else if (op == TOK_BNOT)
rez = ~rez;
else if (op == TOK_POST_INC || op == TOK_PRE_INC)
rez++;
else if (op == TOK_POST_DEC || op == TOK_PRE_DEC)
rez--;
else if (op != TOK_UPLUS) {
/* Binary operators */
/* check and binary operators need two arguments */
if (numptr_m1 == numstack) goto err;
/* ... and they pop one */
--NUMPTR;
numptr_val = rez;
if (op == TOK_CONDITIONAL) {
if (!numptr_m1->contidional_second_val_initialized) {
/* protect $((expr1 ? expr2)) without ": expr" */
goto err;
}
rez = numptr_m1->contidional_second_val;
} else if (numptr_m1->contidional_second_val_initialized) {
/* protect $((expr1 : expr2)) without "expr ? " */
goto err;
}
numptr_m1 = NUMPTR - 1;
if (op != TOK_ASSIGN) {
/* check operand is var with noninteger value for not '=' */
ret_arith_lookup_val = arith_lookup_val(numptr_m1);
if (ret_arith_lookup_val)
return ret_arith_lookup_val;
}
if (op == TOK_CONDITIONAL) {
numptr_m1->contidional_second_val = rez;
}
rez = numptr_m1->val;
if (op == TOK_BOR || op == TOK_OR_ASSIGN)
rez |= numptr_val;
else if (op == TOK_OR)
rez = numptr_val || rez;
else if (op == TOK_BAND || op == TOK_AND_ASSIGN)
rez &= numptr_val;
else if (op == TOK_BXOR || op == TOK_XOR_ASSIGN)
rez ^= numptr_val;
else if (op == TOK_AND)
rez = rez && numptr_val;
else if (op == TOK_EQ)
rez = (rez == numptr_val);
else if (op == TOK_NE)
rez = (rez != numptr_val);
else if (op == TOK_GE)
rez = (rez >= numptr_val);
else if (op == TOK_RSHIFT || op == TOK_RSHIFT_ASSIGN)
rez >>= numptr_val;
else if (op == TOK_LSHIFT || op == TOK_LSHIFT_ASSIGN)
rez <<= numptr_val;
else if (op == TOK_GT)
rez = (rez > numptr_val);
else if (op == TOK_LT)
rez = (rez < numptr_val);
else if (op == TOK_LE)
rez = (rez <= numptr_val);
else if (op == TOK_MUL || op == TOK_MUL_ASSIGN)
rez *= numptr_val;
else if (op == TOK_ADD || op == TOK_PLUS_ASSIGN)
rez += numptr_val;
else if (op == TOK_SUB || op == TOK_MINUS_ASSIGN)
rez -= numptr_val;
else if (op == TOK_ASSIGN || op == TOK_COMMA)
rez = numptr_val;
else if (op == TOK_CONDITIONAL_SEP) {
if (numptr_m1 == numstack) {
/* protect $((expr : expr)) without "expr ? " */
goto err;
}
numptr_m1->contidional_second_val_initialized = op;
numptr_m1->contidional_second_val = numptr_val;
} else if (op == TOK_CONDITIONAL) {
rez = rez ?
numptr_val : numptr_m1->contidional_second_val;
} else if (op == TOK_EXPONENT) {
if (numptr_val < 0)
return -3; /* exponent less than 0 */
else {
arith_t c = 1;
if (numptr_val)
while (numptr_val--)
c *= rez;
rez = c;
}
} else if (numptr_val==0) /* zero divisor check */
return -2;
else if (op == TOK_DIV || op == TOK_DIV_ASSIGN)
rez /= numptr_val;
else if (op == TOK_REM || op == TOK_REM_ASSIGN)
rez %= numptr_val;
}
if (tok_have_assign(op)) {
char buf[sizeof(arith_t_type)*3 + 2];
if (numptr_m1->var == NULL) {
/* Hmm, 1=2 ? */
goto err;
}
/* save to shell variable */
#if ENABLE_ASH_MATH_SUPPORT_64
snprintf(buf, sizeof(buf), "%lld", (arith_t_type) rez);
#else
snprintf(buf, sizeof(buf), "%ld", (arith_t_type) rez);
#endif
setvar(numptr_m1->var, buf, 0);
/* after saving, make previous value for v++ or v-- */
if (op == TOK_POST_INC)
rez--;
else if (op == TOK_POST_DEC)
rez++;
}
numptr_m1->val = rez;
/* protect geting var value, is number now */
numptr_m1->var = NULL;
return 0;
err:
return -1;
}
/* longest must be first */
static const char op_tokens[] ALIGN1 = {
'<','<','=',0, TOK_LSHIFT_ASSIGN,
'>','>','=',0, TOK_RSHIFT_ASSIGN,
'<','<', 0, TOK_LSHIFT,
'>','>', 0, TOK_RSHIFT,
'|','|', 0, TOK_OR,
'&','&', 0, TOK_AND,
'!','=', 0, TOK_NE,
'<','=', 0, TOK_LE,
'>','=', 0, TOK_GE,
'=','=', 0, TOK_EQ,
'|','=', 0, TOK_OR_ASSIGN,
'&','=', 0, TOK_AND_ASSIGN,
'*','=', 0, TOK_MUL_ASSIGN,
'/','=', 0, TOK_DIV_ASSIGN,
'%','=', 0, TOK_REM_ASSIGN,
'+','=', 0, TOK_PLUS_ASSIGN,
'-','=', 0, TOK_MINUS_ASSIGN,
'-','-', 0, TOK_POST_DEC,
'^','=', 0, TOK_XOR_ASSIGN,
'+','+', 0, TOK_POST_INC,
'*','*', 0, TOK_EXPONENT,
'!', 0, TOK_NOT,
'<', 0, TOK_LT,
'>', 0, TOK_GT,
'=', 0, TOK_ASSIGN,
'|', 0, TOK_BOR,
'&', 0, TOK_BAND,
'*', 0, TOK_MUL,
'/', 0, TOK_DIV,
'%', 0, TOK_REM,
'+', 0, TOK_ADD,
'-', 0, TOK_SUB,
'^', 0, TOK_BXOR,
/* uniq */
'~', 0, TOK_BNOT,
',', 0, TOK_COMMA,
'?', 0, TOK_CONDITIONAL,
':', 0, TOK_CONDITIONAL_SEP,
')', 0, TOK_RPAREN,
'(', 0, TOK_LPAREN,
0
};
/* ptr to ")" */
#define endexpression (&op_tokens[sizeof(op_tokens)-7])
static arith_t
arith(const char *expr, int *perrcode)
{
char arithval; /* Current character under analysis */
operator lasttok, op;
operator prec;
operator *stack, *stackptr;
const char *p = endexpression;
int errcode;
v_n_t *numstack, *numstackptr;
unsigned datasizes = strlen(expr) + 2;
/* Stack of integers */
/* The proof that there can be no more than strlen(startbuf)/2+1 integers
* in any given correct or incorrect expression is left as an exercise to
* the reader. */
numstackptr = numstack = alloca((datasizes / 2) * sizeof(numstack[0]));
/* Stack of operator tokens */
stackptr = stack = alloca(datasizes * sizeof(stack[0]));
*stackptr++ = lasttok = TOK_LPAREN; /* start off with a left paren */
*perrcode = errcode = 0;
while (1) {
arithval = *expr;
if (arithval == 0) {
if (p == endexpression) {
/* Null expression. */
return 0;
}
/* This is only reached after all tokens have been extracted from the
* input stream. If there are still tokens on the operator stack, they
* are to be applied in order. At the end, there should be a final
* result on the integer stack */
if (expr != endexpression + 1) {
/* If we haven't done so already, */
/* append a closing right paren */
expr = endexpression;
/* and let the loop process it. */
continue;
}
/* At this point, we're done with the expression. */
if (numstackptr != numstack+1) {
/* ... but if there isn't, it's bad */
err:
*perrcode = -1;
return *perrcode;
}
if (numstack->var) {
/* expression is $((var)) only, lookup now */
errcode = arith_lookup_val(numstack);
}
ret:
*perrcode = errcode;
return numstack->val;
}
/* Continue processing the expression. */
if (arith_isspace(arithval)) {
/* Skip whitespace */
goto prologue;
}
p = endofname(expr);
if (p != expr) {
size_t var_name_size = (p-expr) + 1; /* trailing zero */
numstackptr->var = alloca(var_name_size);
safe_strncpy(numstackptr->var, expr, var_name_size);
expr = p;
num:
numstackptr->contidional_second_val_initialized = 0;
numstackptr++;
lasttok = TOK_NUM;
continue;
}
if (isdigit(arithval)) {
numstackptr->var = NULL;
#if ENABLE_ASH_MATH_SUPPORT_64
numstackptr->val = strtoll(expr, (char **) &expr, 0);
#else
numstackptr->val = strtol(expr, (char **) &expr, 0);
#endif
goto num;
}
for (p = op_tokens; ; p++) {
const char *o;
if (*p == 0) {
/* strange operator not found */
goto err;
}
for (o = expr; *p && *o == *p; p++)
o++;
if (!*p) {
/* found */
expr = o - 1;
break;
}
/* skip tail uncompared token */
while (*p)
p++;
/* skip zero delim */
p++;
}
op = p[1];
/* post grammar: a++ reduce to num */
if (lasttok == TOK_POST_INC || lasttok == TOK_POST_DEC)
lasttok = TOK_NUM;
/* Plus and minus are binary (not unary) _only_ if the last
* token was as number, or a right paren (which pretends to be
* a number, since it evaluates to one). Think about it.
* It makes sense. */
if (lasttok != TOK_NUM) {
switch (op) {
case TOK_ADD:
op = TOK_UPLUS;
break;
case TOK_SUB:
op = TOK_UMINUS;
break;
case TOK_POST_INC:
op = TOK_PRE_INC;
break;
case TOK_POST_DEC:
op = TOK_PRE_DEC;
break;
}
}
/* We don't want a unary operator to cause recursive descent on the
* stack, because there can be many in a row and it could cause an
* operator to be evaluated before its argument is pushed onto the
* integer stack. */
/* But for binary operators, "apply" everything on the operator
* stack until we find an operator with a lesser priority than the
* one we have just extracted. */
/* Left paren is given the lowest priority so it will never be
* "applied" in this way.
* if associativity is right and priority eq, applied also skip
*/
prec = PREC(op);
if ((prec > 0 && prec < UNARYPREC) || prec == SPEC_PREC) {
/* not left paren or unary */
if (lasttok != TOK_NUM) {
/* binary op must be preceded by a num */
goto err;
}
while (stackptr != stack) {
if (op == TOK_RPAREN) {
/* The algorithm employed here is simple: while we don't
* hit an open paren nor the bottom of the stack, pop
* tokens and apply them */
if (stackptr[-1] == TOK_LPAREN) {
--stackptr;
/* Any operator directly after a */
lasttok = TOK_NUM;
/* close paren should consider itself binary */
goto prologue;
}
} else {
operator prev_prec = PREC(stackptr[-1]);
convert_prec_is_assing(prec);
convert_prec_is_assing(prev_prec);
if (prev_prec < prec)
break;
/* check right assoc */
if (prev_prec == prec && is_right_associativity(prec))
break;
}
errcode = arith_apply(*--stackptr, numstack, &numstackptr);
if (errcode) goto ret;
}
if (op == TOK_RPAREN) {
goto err;
}
}
/* Push this operator to the stack and remember it. */
*stackptr++ = lasttok = op;
prologue:
++expr;
} /* while */
}
#endif /* ASH_MATH_SUPPORT */
/* ============ main() and helpers */
/*
@ -13786,7 +13117,7 @@ extern int etext();
int ash_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int ash_main(int argc UNUSED_PARAM, char **argv)
{
char *shinit;
const char *shinit;
volatile smallint state;
struct jmploc jmploc;
struct stackmark smark;
@ -13799,6 +13130,11 @@ int ash_main(int argc UNUSED_PARAM, char **argv)
INIT_G_alias();
#endif
INIT_G_cmdtable();
#if ENABLE_SH_MATH_SUPPORT
math_hooks.lookupvar = lookupvar;
math_hooks.setvar = setvar;
math_hooks.endofname = endofname;
#endif
#if PROFILE
monitor(4, etext, profile_buf, sizeof(profile_buf), 50);

102
shell/hush.c
View File

@ -76,6 +76,8 @@
#include <fnmatch.h>
#endif
#include "math.h"
#define HUSH_VER_STR "0.92"
#if defined SINGLE_APPLET_MAIN
@ -451,6 +453,9 @@ struct globals {
#endif
#if ENABLE_FEATURE_EDITING
line_input_t *line_input_state;
#endif
#if ENABLE_SH_MATH_SUPPORT
arith_eval_hooks_t hooks;
#endif
pid_t root_pid;
pid_t last_bg_pid;
@ -1164,6 +1169,31 @@ static int unset_local_var(const char *name)
return EXIT_SUCCESS;
}
#if ENABLE_SH_MATH_SUPPORT
#define is_name(c) ((c) == '_' || isalpha((unsigned char)(c)))
#define is_in_name(c) ((c) == '_' || isalnum((unsigned char)(c)))
static char *endofname(const char *name)
{
char *p;
p = (char *) name;
if (!is_name(*p))
return p;
while (*++p) {
if (!is_in_name(*p))
break;
}
return p;
}
static void arith_set_local_var(const char *name, const char *val, int flags)
{
/* arith code doesnt malloc space, so do it for it */
char *var = xmalloc(strlen(name) + 1 + strlen(val) + 1);
sprintf(var, "%s=%s", name, val);
set_local_var(var, flags);
}
#endif
/*
* in_str support
@ -1374,6 +1404,11 @@ static void o_addstr(o_string *o, const char *str, int len)
o->data[o->length] = '\0';
}
static void o_addstrauto(o_string *o, const char *str)
{
o_addstr(o, str, strlen(str) + 1);
}
static void o_addstr_duplicate_backslash(o_string *o, const char *str, int len)
{
while (len) {
@ -1564,7 +1599,7 @@ static int o_glob(o_string *o, int n)
char **argv = globdata.gl_pathv;
o->length = pattern - o->data; /* "forget" pattern */
while (1) {
o_addstr(o, *argv, strlen(*argv) + 1);
o_addstrauto(o, *argv);
n = o_save_ptr_helper(o, n);
argv++;
if (!*argv)
@ -1769,6 +1804,28 @@ static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask)
val = subst_result.data;
goto store_val;
}
#endif
#if ENABLE_SH_MATH_SUPPORT
case '+': { /* <SPECIAL_VAR_SYMBOL>(cmd<SPECIAL_VAR_SYMBOL> */
arith_t res;
char buf[30];
int errcode;
*p = '\0';
++arg;
debug_printf_subst("ARITH '%s' first_ch %x\n", arg, first_ch);
res = arith(arg, &errcode, &G.hooks);
if (errcode < 0)
switch (errcode) {
case -3: maybe_die("arith", "exponent less than 0"); break;
case -2: maybe_die("arith", "divide by zero"); break;
case -5: maybe_die("arith", "expression recursion loop detected"); break;
default: maybe_die("arith", "syntax error");
}
sprintf(buf, arith_t_fmt, res);
o_addstrauto(output, buf);
debug_printf_subst("ARITH RES '"arith_t_fmt"'\n", res);
break;
}
#endif
default: /* <SPECIAL_VAR_SYMBOL>varname<SPECIAL_VAR_SYMBOL> */
case_default: {
@ -1877,7 +1934,7 @@ static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask)
debug_print_list("expand_vars_to_list[a]", output, n);
/* this part is literal, and it was already pre-quoted
* if needed (much earlier), do not use o_addQstr here! */
o_addstr(output, arg, strlen(arg) + 1);
o_addstrauto(output, arg);
debug_print_list("expand_vars_to_list[b]", output, n);
} else if (output->length == o_get_last_ptr(output, n) /* expansion is empty */
&& !(ored_ch & 0x80) /* and all vars were not quoted. */
@ -3754,7 +3811,7 @@ static int parse_group(o_string *dest, struct parse_context *ctx,
/* command remains "open", available for possible redirects */
}
#if ENABLE_HUSH_TICK
#if ENABLE_HUSH_TICK || ENABLE_SH_MATH_SUPPORT
/* Subroutines for copying $(...) and `...` things */
static void add_till_backquote(o_string *dest, struct in_str *input);
/* '...' */
@ -3834,7 +3891,7 @@ static void add_till_backquote(o_string *dest, struct in_str *input)
* echo $(echo 'TEST)' BEST) TEST) BEST
* echo $(echo \(\(TEST\) BEST) ((TEST) BEST
*/
static void add_till_closing_curly_brace(o_string *dest, struct in_str *input)
static void add_till_closing_paren(o_string *dest, struct in_str *input, bool dbl)
{
int count = 0;
while (1) {
@ -3844,8 +3901,14 @@ static void add_till_closing_curly_brace(o_string *dest, struct in_str *input)
if (ch == '(')
count++;
if (ch == ')')
if (--count < 0)
if (--count < 0) {
if (!dbl)
break;
if (i_peek(input) == ')') {
i_getch(input);
break;
}
}
o_addchr(dest, ch);
if (ch == '\'') {
add_till_single_quote(dest, input);
@ -3866,7 +3929,7 @@ static void add_till_closing_curly_brace(o_string *dest, struct in_str *input)
}
}
}
#endif /* ENABLE_HUSH_TICK */
#endif /* ENABLE_HUSH_TICK || ENABLE_SH_MATH_SUPPORT */
/* Return code: 0 for OK, 1 for syntax error */
static int handle_dollar(o_string *dest, struct in_str *input)
@ -3983,18 +4046,30 @@ static int handle_dollar(o_string *dest, struct in_str *input)
o_addchr(dest, SPECIAL_VAR_SYMBOL);
break;
}
#if ENABLE_HUSH_TICK
case '(': {
//int pos = dest->length;
i_getch(input);
#if ENABLE_SH_MATH_SUPPORT
if (i_peek(input) == '(') {
i_getch(input);
o_addchr(dest, SPECIAL_VAR_SYMBOL);
o_addchr(dest, quote_mask | '`');
add_till_closing_curly_brace(dest, input);
//debug_printf_subst("SUBST RES2 '%s'\n", dest->data + pos);
o_addchr(dest, quote_mask | '+');
add_till_closing_paren(dest, input, true);
o_addchr(dest, SPECIAL_VAR_SYMBOL);
break;
}
#endif
#if ENABLE_HUSH_TICK
//int pos = dest->length;
o_addchr(dest, SPECIAL_VAR_SYMBOL);
o_addchr(dest, quote_mask | '`');
add_till_closing_paren(dest, input, false);
//debug_printf_subst("SUBST RES2 '%s'\n", dest->data + pos);
o_addchr(dest, SPECIAL_VAR_SYMBOL);
#endif
break;
}
case '_':
i_getch(input);
ch = i_peek(input);
@ -4525,6 +4600,11 @@ int hush_main(int argc, char **argv)
#if ENABLE_FEATURE_EDITING
G.line_input_state = new_line_input_t(FOR_SHELL);
#endif
#if ENABLE_SH_MATH_SUPPORT
G.hooks.lookupvar = lookup_param;
G.hooks.setvar = arith_set_local_var;
G.hooks.endofname = endofname;
#endif
/* XXX what should these be while sourcing /etc/profile? */
G.global_argc = argc;

701
shell/math.c Normal file
View File

@ -0,0 +1,701 @@
/*
* arithmetic code ripped out of ash shell for code sharing
*
* Copyright (c) 1989, 1991, 1993, 1994
* The Regents of the University of California. All rights reserved.
*
* Copyright (c) 1997-2005 Herbert Xu <herbert@gondor.apana.org.au>
* was re-ported from NetBSD and debianized.
*
* This code is derived from software contributed to Berkeley by
* Kenneth Almquist.
*
* Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
*
* Original BSD copyright notice is retained at the end of this file.
*/
/*
* rewrite arith.y to micro stack based cryptic algorithm by
* Copyright (c) 2001 Aaron Lehmann <aaronl@vitelus.com>
*
* Modified by Paul Mundt <lethal@linux-sh.org> (c) 2004 to support
* dynamic variables.
*
* Modified by Vladimir Oleynik <dzo@simtreas.ru> (c) 2001-2005 to be
* used in busybox and size optimizations,
* rewrote arith (see notes to this), added locale support,
* rewrote dynamic variables.
*/
#include "busybox.h"
#include "math.h"
#define a_e_h_t arith_eval_hooks_t
#define lookupvar (math_hooks->lookupvar)
#define setvar (math_hooks->setvar)
#define endofname (math_hooks->endofname)
/* Copyright (c) 2001 Aaron Lehmann <aaronl@vitelus.com>
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:
The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
/* This is my infix parser/evaluator. It is optimized for size, intended
* as a replacement for yacc-based parsers. However, it may well be faster
* than a comparable parser written in yacc. The supported operators are
* listed in #defines below. Parens, order of operations, and error handling
* are supported. This code is thread safe. The exact expression format should
* be that which POSIX specifies for shells. */
/* The code uses a simple two-stack algorithm. See
* http://www.onthenet.com.au/~grahamis/int2008/week02/lect02.html
* for a detailed explanation of the infix-to-postfix algorithm on which
* this is based (this code differs in that it applies operators immediately
* to the stack instead of adding them to a queue to end up with an
* expression). */
/* To use the routine, call it with an expression string and error return
* pointer */
/*
* Aug 24, 2001 Manuel Novoa III
*
* Reduced the generated code size by about 30% (i386) and fixed several bugs.
*
* 1) In arith_apply():
* a) Cached values of *numptr and &(numptr[-1]).
* b) Removed redundant test for zero denominator.
*
* 2) In arith():
* a) Eliminated redundant code for processing operator tokens by moving
* to a table-based implementation. Also folded handling of parens
* into the table.
* b) Combined all 3 loops which called arith_apply to reduce generated
* code size at the cost of speed.
*
* 3) The following expressions were treated as valid by the original code:
* 1() , 0! , 1 ( *3 ) .
* These bugs have been fixed by internally enclosing the expression in
* parens and then checking that all binary ops and right parens are
* preceded by a valid expression (NUM_TOKEN).
*
* Note: It may be desirable to replace Aaron's test for whitespace with
* ctype's isspace() if it is used by another busybox applet or if additional
* whitespace chars should be considered. Look below the "#include"s for a
* precompiler test.
*/
/*
* Aug 26, 2001 Manuel Novoa III
*
* Return 0 for null expressions. Pointed out by Vladimir Oleynik.
*
* Merge in Aaron's comments previously posted to the busybox list,
* modified slightly to take account of my changes to the code.
*
*/
/*
* (C) 2003 Vladimir Oleynik <dzo@simtreas.ru>
*
* - allow access to variable,
* used recursive find value indirection (c=2*2; a="c"; $((a+=2)) produce 6)
* - realize assign syntax (VAR=expr, +=, *= etc)
* - realize exponentiation (** operator)
* - realize comma separated - expr, expr
* - realise ++expr --expr expr++ expr--
* - realise expr ? expr : expr (but, second expr calculate always)
* - allow hexadecimal and octal numbers
* - was restored loses XOR operator
* - remove one goto label, added three ;-)
* - protect $((num num)) as true zero expr (Manuel`s error)
* - always use special isspace(), see comment from bash ;-)
*/
#define arith_isspace(arithval) \
(arithval == ' ' || arithval == '\n' || arithval == '\t')
typedef unsigned char operator;
/* An operator's token id is a bit of a bitfield. The lower 5 bits are the
* precedence, and 3 high bits are an ID unique across operators of that
* precedence. The ID portion is so that multiple operators can have the
* same precedence, ensuring that the leftmost one is evaluated first.
* Consider * and /. */
#define tok_decl(prec,id) (((id)<<5)|(prec))
#define PREC(op) ((op) & 0x1F)
#define TOK_LPAREN tok_decl(0,0)
#define TOK_COMMA tok_decl(1,0)
#define TOK_ASSIGN tok_decl(2,0)
#define TOK_AND_ASSIGN tok_decl(2,1)
#define TOK_OR_ASSIGN tok_decl(2,2)
#define TOK_XOR_ASSIGN tok_decl(2,3)
#define TOK_PLUS_ASSIGN tok_decl(2,4)
#define TOK_MINUS_ASSIGN tok_decl(2,5)
#define TOK_LSHIFT_ASSIGN tok_decl(2,6)
#define TOK_RSHIFT_ASSIGN tok_decl(2,7)
#define TOK_MUL_ASSIGN tok_decl(3,0)
#define TOK_DIV_ASSIGN tok_decl(3,1)
#define TOK_REM_ASSIGN tok_decl(3,2)
/* all assign is right associativity and precedence eq, but (7+3)<<5 > 256 */
#define convert_prec_is_assing(prec) do { if (prec == 3) prec = 2; } while (0)
/* conditional is right associativity too */
#define TOK_CONDITIONAL tok_decl(4,0)
#define TOK_CONDITIONAL_SEP tok_decl(4,1)
#define TOK_OR tok_decl(5,0)
#define TOK_AND tok_decl(6,0)
#define TOK_BOR tok_decl(7,0)
#define TOK_BXOR tok_decl(8,0)
#define TOK_BAND tok_decl(9,0)
#define TOK_EQ tok_decl(10,0)
#define TOK_NE tok_decl(10,1)
#define TOK_LT tok_decl(11,0)
#define TOK_GT tok_decl(11,1)
#define TOK_GE tok_decl(11,2)
#define TOK_LE tok_decl(11,3)
#define TOK_LSHIFT tok_decl(12,0)
#define TOK_RSHIFT tok_decl(12,1)
#define TOK_ADD tok_decl(13,0)
#define TOK_SUB tok_decl(13,1)
#define TOK_MUL tok_decl(14,0)
#define TOK_DIV tok_decl(14,1)
#define TOK_REM tok_decl(14,2)
/* exponent is right associativity */
#define TOK_EXPONENT tok_decl(15,1)
/* For now unary operators. */
#define UNARYPREC 16
#define TOK_BNOT tok_decl(UNARYPREC,0)
#define TOK_NOT tok_decl(UNARYPREC,1)
#define TOK_UMINUS tok_decl(UNARYPREC+1,0)
#define TOK_UPLUS tok_decl(UNARYPREC+1,1)
#define PREC_PRE (UNARYPREC+2)
#define TOK_PRE_INC tok_decl(PREC_PRE, 0)
#define TOK_PRE_DEC tok_decl(PREC_PRE, 1)
#define PREC_POST (UNARYPREC+3)
#define TOK_POST_INC tok_decl(PREC_POST, 0)
#define TOK_POST_DEC tok_decl(PREC_POST, 1)
#define SPEC_PREC (UNARYPREC+4)
#define TOK_NUM tok_decl(SPEC_PREC, 0)
#define TOK_RPAREN tok_decl(SPEC_PREC, 1)
#define NUMPTR (*numstackptr)
static int
tok_have_assign(operator op)
{
operator prec = PREC(op);
convert_prec_is_assing(prec);
return (prec == PREC(TOK_ASSIGN) ||
prec == PREC_PRE || prec == PREC_POST);
}
static int
is_right_associativity(operator prec)
{
return (prec == PREC(TOK_ASSIGN) || prec == PREC(TOK_EXPONENT)
|| prec == PREC(TOK_CONDITIONAL));
}
typedef struct {
arith_t val;
arith_t contidional_second_val;
char contidional_second_val_initialized;
char *var; /* if NULL then is regular number,
else is variable name */
} v_n_t;
typedef struct chk_var_recursive_looped_t {
const char *var;
struct chk_var_recursive_looped_t *next;
} chk_var_recursive_looped_t;
static chk_var_recursive_looped_t *prev_chk_var_recursive;
static int
arith_lookup_val(v_n_t *t, a_e_h_t *math_hooks)
{
if (t->var) {
const char * p = lookupvar(t->var);
if (p) {
int errcode;
/* recursive try as expression */
chk_var_recursive_looped_t *cur;
chk_var_recursive_looped_t cur_save;
for (cur = prev_chk_var_recursive; cur; cur = cur->next) {
if (strcmp(cur->var, t->var) == 0) {
/* expression recursion loop detected */
return -5;
}
}
/* save current lookuped var name */
cur = prev_chk_var_recursive;
cur_save.var = t->var;
cur_save.next = cur;
prev_chk_var_recursive = &cur_save;
t->val = arith (p, &errcode, math_hooks);
/* restore previous ptr after recursiving */
prev_chk_var_recursive = cur;
return errcode;
}
/* allow undefined var as 0 */
t->val = 0;
}
return 0;
}
/* "applying" a token means performing it on the top elements on the integer
* stack. For a unary operator it will only change the top element, but a
* binary operator will pop two arguments and push a result */
static int
arith_apply(operator op, v_n_t *numstack, v_n_t **numstackptr, a_e_h_t *math_hooks)
{
v_n_t *numptr_m1;
arith_t numptr_val, rez;
int ret_arith_lookup_val;
/* There is no operator that can work without arguments */
if (NUMPTR == numstack) goto err;
numptr_m1 = NUMPTR - 1;
/* check operand is var with noninteger value */
ret_arith_lookup_val = arith_lookup_val(numptr_m1, math_hooks);
if (ret_arith_lookup_val)
return ret_arith_lookup_val;
rez = numptr_m1->val;
if (op == TOK_UMINUS)
rez *= -1;
else if (op == TOK_NOT)
rez = !rez;
else if (op == TOK_BNOT)
rez = ~rez;
else if (op == TOK_POST_INC || op == TOK_PRE_INC)
rez++;
else if (op == TOK_POST_DEC || op == TOK_PRE_DEC)
rez--;
else if (op != TOK_UPLUS) {
/* Binary operators */
/* check and binary operators need two arguments */
if (numptr_m1 == numstack) goto err;
/* ... and they pop one */
--NUMPTR;
numptr_val = rez;
if (op == TOK_CONDITIONAL) {
if (!numptr_m1->contidional_second_val_initialized) {
/* protect $((expr1 ? expr2)) without ": expr" */
goto err;
}
rez = numptr_m1->contidional_second_val;
} else if (numptr_m1->contidional_second_val_initialized) {
/* protect $((expr1 : expr2)) without "expr ? " */
goto err;
}
numptr_m1 = NUMPTR - 1;
if (op != TOK_ASSIGN) {
/* check operand is var with noninteger value for not '=' */
ret_arith_lookup_val = arith_lookup_val(numptr_m1, math_hooks);
if (ret_arith_lookup_val)
return ret_arith_lookup_val;
}
if (op == TOK_CONDITIONAL) {
numptr_m1->contidional_second_val = rez;
}
rez = numptr_m1->val;
if (op == TOK_BOR || op == TOK_OR_ASSIGN)
rez |= numptr_val;
else if (op == TOK_OR)
rez = numptr_val || rez;
else if (op == TOK_BAND || op == TOK_AND_ASSIGN)
rez &= numptr_val;
else if (op == TOK_BXOR || op == TOK_XOR_ASSIGN)
rez ^= numptr_val;
else if (op == TOK_AND)
rez = rez && numptr_val;
else if (op == TOK_EQ)
rez = (rez == numptr_val);
else if (op == TOK_NE)
rez = (rez != numptr_val);
else if (op == TOK_GE)
rez = (rez >= numptr_val);
else if (op == TOK_RSHIFT || op == TOK_RSHIFT_ASSIGN)
rez >>= numptr_val;
else if (op == TOK_LSHIFT || op == TOK_LSHIFT_ASSIGN)
rez <<= numptr_val;
else if (op == TOK_GT)
rez = (rez > numptr_val);
else if (op == TOK_LT)
rez = (rez < numptr_val);
else if (op == TOK_LE)
rez = (rez <= numptr_val);
else if (op == TOK_MUL || op == TOK_MUL_ASSIGN)
rez *= numptr_val;
else if (op == TOK_ADD || op == TOK_PLUS_ASSIGN)
rez += numptr_val;
else if (op == TOK_SUB || op == TOK_MINUS_ASSIGN)
rez -= numptr_val;
else if (op == TOK_ASSIGN || op == TOK_COMMA)
rez = numptr_val;
else if (op == TOK_CONDITIONAL_SEP) {
if (numptr_m1 == numstack) {
/* protect $((expr : expr)) without "expr ? " */
goto err;
}
numptr_m1->contidional_second_val_initialized = op;
numptr_m1->contidional_second_val = numptr_val;
} else if (op == TOK_CONDITIONAL) {
rez = rez ?
numptr_val : numptr_m1->contidional_second_val;
} else if (op == TOK_EXPONENT) {
if (numptr_val < 0)
return -3; /* exponent less than 0 */
else {
arith_t c = 1;
if (numptr_val)
while (numptr_val--)
c *= rez;
rez = c;
}
} else if (numptr_val==0) /* zero divisor check */
return -2;
else if (op == TOK_DIV || op == TOK_DIV_ASSIGN)
rez /= numptr_val;
else if (op == TOK_REM || op == TOK_REM_ASSIGN)
rez %= numptr_val;
}
if (tok_have_assign(op)) {
char buf[sizeof(arith_t_type)*3 + 2];
if (numptr_m1->var == NULL) {
/* Hmm, 1=2 ? */
goto err;
}
/* save to shell variable */
snprintf(buf, sizeof(buf), arith_t_fmt, (arith_t_type) rez);
setvar(numptr_m1->var, buf, 0);
/* after saving, make previous value for v++ or v-- */
if (op == TOK_POST_INC)
rez--;
else if (op == TOK_POST_DEC)
rez++;
}
numptr_m1->val = rez;
/* protect geting var value, is number now */
numptr_m1->var = NULL;
return 0;
err:
return -1;
}
/* longest must be first */
static const char op_tokens[] ALIGN1 = {
'<','<','=',0, TOK_LSHIFT_ASSIGN,
'>','>','=',0, TOK_RSHIFT_ASSIGN,
'<','<', 0, TOK_LSHIFT,
'>','>', 0, TOK_RSHIFT,
'|','|', 0, TOK_OR,
'&','&', 0, TOK_AND,
'!','=', 0, TOK_NE,
'<','=', 0, TOK_LE,
'>','=', 0, TOK_GE,
'=','=', 0, TOK_EQ,
'|','=', 0, TOK_OR_ASSIGN,
'&','=', 0, TOK_AND_ASSIGN,
'*','=', 0, TOK_MUL_ASSIGN,
'/','=', 0, TOK_DIV_ASSIGN,
'%','=', 0, TOK_REM_ASSIGN,
'+','=', 0, TOK_PLUS_ASSIGN,
'-','=', 0, TOK_MINUS_ASSIGN,
'-','-', 0, TOK_POST_DEC,
'^','=', 0, TOK_XOR_ASSIGN,
'+','+', 0, TOK_POST_INC,
'*','*', 0, TOK_EXPONENT,
'!', 0, TOK_NOT,
'<', 0, TOK_LT,
'>', 0, TOK_GT,
'=', 0, TOK_ASSIGN,
'|', 0, TOK_BOR,
'&', 0, TOK_BAND,
'*', 0, TOK_MUL,
'/', 0, TOK_DIV,
'%', 0, TOK_REM,
'+', 0, TOK_ADD,
'-', 0, TOK_SUB,
'^', 0, TOK_BXOR,
/* uniq */
'~', 0, TOK_BNOT,
',', 0, TOK_COMMA,
'?', 0, TOK_CONDITIONAL,
':', 0, TOK_CONDITIONAL_SEP,
')', 0, TOK_RPAREN,
'(', 0, TOK_LPAREN,
0
};
/* ptr to ")" */
#define endexpression (&op_tokens[sizeof(op_tokens)-7])
arith_t
arith(const char *expr, int *perrcode, a_e_h_t *math_hooks)
{
char arithval; /* Current character under analysis */
operator lasttok, op;
operator prec;
operator *stack, *stackptr;
const char *p = endexpression;
int errcode;
v_n_t *numstack, *numstackptr;
unsigned datasizes = strlen(expr) + 2;
/* Stack of integers */
/* The proof that there can be no more than strlen(startbuf)/2+1 integers
* in any given correct or incorrect expression is left as an exercise to
* the reader. */
numstackptr = numstack = alloca((datasizes / 2) * sizeof(numstack[0]));
/* Stack of operator tokens */
stackptr = stack = alloca(datasizes * sizeof(stack[0]));
*stackptr++ = lasttok = TOK_LPAREN; /* start off with a left paren */
*perrcode = errcode = 0;
while (1) {
arithval = *expr;
if (arithval == 0) {
if (p == endexpression) {
/* Null expression. */
return 0;
}
/* This is only reached after all tokens have been extracted from the
* input stream. If there are still tokens on the operator stack, they
* are to be applied in order. At the end, there should be a final
* result on the integer stack */
if (expr != endexpression + 1) {
/* If we haven't done so already, */
/* append a closing right paren */
expr = endexpression;
/* and let the loop process it. */
continue;
}
/* At this point, we're done with the expression. */
if (numstackptr != numstack+1) {
/* ... but if there isn't, it's bad */
err:
*perrcode = -1;
return *perrcode;
}
if (numstack->var) {
/* expression is $((var)) only, lookup now */
errcode = arith_lookup_val(numstack, math_hooks);
}
ret:
*perrcode = errcode;
return numstack->val;
}
/* Continue processing the expression. */
if (arith_isspace(arithval)) {
/* Skip whitespace */
goto prologue;
}
p = endofname(expr);
if (p != expr) {
size_t var_name_size = (p-expr) + 1; /* trailing zero */
numstackptr->var = alloca(var_name_size);
safe_strncpy(numstackptr->var, expr, var_name_size);
expr = p;
num:
numstackptr->contidional_second_val_initialized = 0;
numstackptr++;
lasttok = TOK_NUM;
continue;
}
if (isdigit(arithval)) {
numstackptr->var = NULL;
numstackptr->val = strto_arith_t(expr, (char **) &expr, 0);
goto num;
}
for (p = op_tokens; ; p++) {
const char *o;
if (*p == 0) {
/* strange operator not found */
goto err;
}
for (o = expr; *p && *o == *p; p++)
o++;
if (!*p) {
/* found */
expr = o - 1;
break;
}
/* skip tail uncompared token */
while (*p)
p++;
/* skip zero delim */
p++;
}
op = p[1];
/* post grammar: a++ reduce to num */
if (lasttok == TOK_POST_INC || lasttok == TOK_POST_DEC)
lasttok = TOK_NUM;
/* Plus and minus are binary (not unary) _only_ if the last
* token was as number, or a right paren (which pretends to be
* a number, since it evaluates to one). Think about it.
* It makes sense. */
if (lasttok != TOK_NUM) {
switch (op) {
case TOK_ADD:
op = TOK_UPLUS;
break;
case TOK_SUB:
op = TOK_UMINUS;
break;
case TOK_POST_INC:
op = TOK_PRE_INC;
break;
case TOK_POST_DEC:
op = TOK_PRE_DEC;
break;
}
}
/* We don't want a unary operator to cause recursive descent on the
* stack, because there can be many in a row and it could cause an
* operator to be evaluated before its argument is pushed onto the
* integer stack. */
/* But for binary operators, "apply" everything on the operator
* stack until we find an operator with a lesser priority than the
* one we have just extracted. */
/* Left paren is given the lowest priority so it will never be
* "applied" in this way.
* if associativity is right and priority eq, applied also skip
*/
prec = PREC(op);
if ((prec > 0 && prec < UNARYPREC) || prec == SPEC_PREC) {
/* not left paren or unary */
if (lasttok != TOK_NUM) {
/* binary op must be preceded by a num */
goto err;
}
while (stackptr != stack) {
if (op == TOK_RPAREN) {
/* The algorithm employed here is simple: while we don't
* hit an open paren nor the bottom of the stack, pop
* tokens and apply them */
if (stackptr[-1] == TOK_LPAREN) {
--stackptr;
/* Any operator directly after a */
lasttok = TOK_NUM;
/* close paren should consider itself binary */
goto prologue;
}
} else {
operator prev_prec = PREC(stackptr[-1]);
convert_prec_is_assing(prec);
convert_prec_is_assing(prev_prec);
if (prev_prec < prec)
break;
/* check right assoc */
if (prev_prec == prec && is_right_associativity(prec))
break;
}
errcode = arith_apply(*--stackptr, numstack, &numstackptr, math_hooks);
if (errcode) goto ret;
}
if (op == TOK_RPAREN) {
goto err;
}
}
/* Push this operator to the stack and remember it. */
*stackptr++ = lasttok = op;
prologue:
++expr;
} /* while */
}
/*-
* Copyright (c) 1989, 1991, 1993, 1994
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Kenneth Almquist.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/

101
shell/math.h Normal file
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@ -0,0 +1,101 @@
/* math.h - interface to shell math "library" -- this allows shells to share
* the implementation of arithmetic $((...)) expansions.
*
* This aims to be a POSIX shell math library as documented here:
* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_04
*
* See math.c for internal documentation.
*/
/* The math library has just one function:
*
* arith_t arith(const char *expr, int *perrcode, arith_eval_hooks_t *hooks);
*
* The first argument is the math string to parse. All normal expansions must
* be done already. i.e. no dollar symbols should be present.
*
* The second argument is a semi-detailed error description in case something
* goes wrong in the parsing steps. Currently, those values are (for
* compatibility, you should assume all negative values are errors):
* 0 - no errors (yay!)
* -1 - unspecified problem
* -2 - divide by zero
* -3 - exponent less than 0
* -5 - expression recursion loop detected
*
* The third argument is a struct pointer of hooks for your shell (see below).
*
* The function returns the answer to the expression. So if you called it
* with the expression:
* "1 + 2 + 3"
* You would obviously get back 6.
*/
/* To add support to a shell, you need to implement three functions:
*
* lookupvar() - look up and return the value of a variable
*
* If the shell does:
* foo=123
* Then the code:
* const char *val = lookupvar("foo");
* Will result in val pointing to "123"
*
* setvar() - set a variable to some value
*
* If the arithmetic expansion does something like:
* $(( i = 1))
* Then the math code will make a call like so:
* setvar("i", "1", 0);
* The storage for the first two parameters are not allocated, so your
* shell implementation will most likely need to strdup() them to save.
*
* endofname() - return the end of a variable name from input
*
* The arithmetic code does not know about variable naming conventions.
* So when it is given an experession, it knows something is not numeric,
* but it is up to the shell to dictate what is a valid identifiers.
* So when it encounters something like:
* $(( some_var + 123 ))
* It will make a call like so:
* end = endofname("some_var + 123");
* So the shell needs to scan the input string and return a pointer to the
* first non-identifier string. In this case, it should return the input
* pointer with an offset pointing to the first space. The typical
* implementation will return the offset of first char that does not match
* the regex (in C locale): ^[a-zA-Z_][a-zA-Z_0-9]*
*/
/* To make your life easier when dealing with optional 64bit math support,
* rather than assume that the type is "signed long" and you can always
* use "%ld" to scan/print the value, use the arith_t helper defines. See
* below for the exact things that are available.
*/
#ifndef _SHELL_MATH_
#define _SHELL_MATH_
#if ENABLE_SH_MATH_SUPPORT_64
typedef int64_t arith_t;
#define arith_t_type long long
#define arith_t_fmt "%lld"
#define strto_arith_t strtoll
#else
typedef long arith_t;
#define arith_t_type long
#define arith_t_fmt "%ld"
#define strto_arith_t strtol
#endif
typedef const char *(*arith_var_lookup_t)(const char *name);
typedef void (*arith_var_set_t)(const char *name, const char *val, int flags);
typedef char *(*arith_var_endofname_t)(const char *name);
typedef struct arith_eval_hooks {
arith_var_lookup_t lookupvar;
arith_var_set_t setvar;
arith_var_endofname_t endofname;
} arith_eval_hooks_t;
arith_t arith(const char *expr, int *perrcode, arith_eval_hooks_t*);
#endif