On Fri, 23 Mar 2007, Markus Mayer wrote:
> It looks like I discovered a problem with shell arithmetic with large
> number (numbers larger than "signed long").

Here's a patch to make it use intmax_t.  I'd appreciate review from
people who understand yacc better than I do.

--apb (Alan Barrett)

Index: src/bin/sh/arith.y
===================================================================
--- arith.y	17 Sep 2003 17:33:36 -0000	1.17
+++ arith.y	24 Mar 2007 12:46:14 -0000
@@ -49,6 +49,10 @@
 #include "output.h"
 #include "memalloc.h"
 
+typedef intmax_t YYSTYPE;
+#define YYSTYPE YYSTYPE
+
+intmax_t arith_result;
 const char *arith_buf, *arith_startbuf;
 
 void yyerror(const char *);
@@ -74,7 +78,12 @@
 %%
 
 exp:	expr {
-			return ($1);
+			/*
+			 * yyparse() returns int, so we have to save
+			 * the desired result elsewhere.
+			 */
+			arith_result = $1;
+			return 0;
 		}
 	;
 
@@ -113,16 +122,17 @@
 	| ARITH_NUM
 	;
 %%
-int
+intmax_t
 arith(s)
 	const char *s;
 {
-	long result;
+	intmax_t result;
 
 	arith_buf = arith_startbuf = s;
 
 	INTOFF;
-	result = yyparse();
+	(void) yyparse();
+	result = arith_result;
 	arith_lex_reset();	/* reprime lex */
 	INTON;
 
@@ -141,7 +151,7 @@
 	const char *p;
 	char *concat;
 	char **ap;
-	long i;
+	intmax_t i;
 
 	if (argc > 1) {
 		p = argv[1];
@@ -164,9 +174,10 @@
 	} else
 		p = "";
 
-	i = arith(p);
+	(void)arith(p);
+	i = arith_result;
 
-	out1fmt("%ld\n", i);
+	out1fmt("%"PRIdMAX"\n", i);
 	return (! i);
 }
 
@@ -176,7 +187,7 @@
 main(argc, argv)
 	char *argv[];
 {
-	printf("%d\n", exp(argv[1]));
+	printf("%"PRIdMAX"\n", exp(argv[1]));
 }
 error(s)
 	char *s;
Index: src/bin/sh/arith_lex.l
===================================================================
--- arith_lex.l	21 Mar 2005 22:37:09 -0000	1.13
+++ arith_lex.l	24 Mar 2007 12:46:14 -0000
@@ -48,8 +48,8 @@
 #include "expand.h"
 #include "var.h"
 
-extern int yylval;
-extern char *arith_buf, *arith_startbuf;
+extern intmax_t yylval;
+extern const char *arith_buf, *arith_startbuf;
 #undef YY_INPUT
 #define YY_INPUT(buf,result,max) \
 	result = (*buf = *arith_buf++) ? 1 : YY_NULL;
@@ -58,12 +58,12 @@
 
 %%
 [ \t\n]	{ ; }
-0x[0-9a-fA-F]+	{ yylval = strtol(yytext, 0, 0); return(ARITH_NUM); }
-0[0-7]*		{ yylval = strtol(yytext, 0, 0); return(ARITH_NUM); }
-[1-9][0-9]*	{ yylval = strtol(yytext, 0, 0); return(ARITH_NUM); }
+0x[0-9a-fA-F]+	{ yylval = strtoimax(yytext, 0, 0); return(ARITH_NUM); }
+0[0-7]*		{ yylval = strtoimax(yytext, 0, 0); return(ARITH_NUM); }
+[1-9][0-9]*	{ yylval = strtoimax(yytext, 0, 0); return(ARITH_NUM); }
 [A-Za-z_][A-Za-z_0-9]*	{ char *v = lookupvar(yytext);
 			if (v) {
-				yylval = strtol(v, &v, 0);
+				yylval = strtoimax(v, &v, 0);
 				if (*v == 0)
 					return ARITH_NUM;
 			}
Index: src/bin/sh/expand.c
===================================================================
--- expand.c	24 Nov 2006 22:54:47 -0000	1.77
+++ expand.c	24 Mar 2007 12:46:15 -0000
@@ -352,7 +352,8 @@
 expari(int flag)
 {
 	char *p, *start;
-	int result;
+	intmax_t result;
+	int adjustment;
 	int begoff;
 	int quotes = flag & (EXP_FULL | EXP_CASE);
 	int quoted;
@@ -369,10 +370,9 @@
 	 * have to rescan starting from the beginning since CTLESC
 	 * characters have to be processed left to right.
 	 */
-#if INT_MAX / 1000000000 >= 10 || INT_MIN / 1000000000 <= -10
-#error "integers with more than 10 digits are not supported"
-#endif
-	CHECKSTRSPACE(12 - 2, expdest);
+/* SPACE_NEEDED is enough for all digits, plus possible "-", plus 2 (why?) */
+#define SPACE_NEEDED ((sizeof(intmax_t) * CHAR_BIT + 2) / 3 + 1 + 2)
+	CHECKSTRSPACE(SPACE_NEEDED - 2, expdest);
 	USTPUTC('\0', expdest);
 	start = stackblock();
 	p = expdest - 1;
@@ -394,15 +394,15 @@
 	if (quotes)
 		rmescapes(p+2);
 	result = arith(p+2);
-	fmtstr(p, 12, "%d", result);
+	fmtstr(p, SPACE_NEEDED, "%"PRIdMAX, result);
 
 	while (*p++)
 		;
 
 	if (quoted == 0)
 		recordregion(begoff, p - 1 - start, 0);
-	result = expdest - p + 1;
-	STADJUST(-result, expdest);
+	adjustment = expdest - p + 1;
+	STADJUST(-adjustment, expdest);
 }
 
 
Index: src/bin/sh/expand.h
===================================================================
--- expand.h	13 Jul 2004 15:05:59 -0000	1.16
+++ expand.h	24 Mar 2007 12:46:15 -0000
@@ -34,6 +34,8 @@
  *	@(#)expand.h	8.2 (Berkeley) 5/4/95
  */
 
+#include <inttypes.h>
+
 struct strlist {
 	struct strlist *next;
 	char *text;
@@ -66,7 +68,7 @@
 int wordexpcmd(int, char **);
 
 /* From arith.y */
-int arith(const char *);
+intmax_t arith(const char *);
 int expcmd(int , char **);
 void arith_lex_reset(void);
 int yylex(void);