Обсуждение: 8.1beta, Subtle bug in COPY in Solaris systems

Hello, 

First, I'll show the warnings seen when compiling postgres on 
SunOS 5.6 with gcc 3.2.1

copy.c: In function `GetDecimalFromHex':
copy.c:2660: warning: subscript has type `char'
copy.c: In function `CopyReadAttributesText':
copy.c:2805: warning: subscript has type `char'
copy.c:2813: warning: subscript has type `char'

Actually this warnings are caused by the isdigit function.
On Solaris systems, isdigit is organized as an array lookup, so all the 
arguments should be casted to unsigned char. 

2660c2660
<       if (isdigit(hex))
---
>       if (isdigit((unsigned char)hex))
2805c2805
<                                                       if (isxdigit(hexchar))
---
>                                                       if (isxdigit((unsigned char)hexchar))
2813c2813
<                                                                       if (isxdigit(hexchar))
---
>                                                                       if (isxdigit((unsigned char)hexchar))



Actually that problem cause not only warnings but real bugs too,
exploiting that problem. (when the char >128 and is not casted to 
unsigned, on  solaris there will be a negative indices of arrays)

For example on SunOS (or any Solaris):

test=# CREATE TABLE test0 (xx char(2));
CREATE TABLE
test=# copy test0 from stdin;
Enter data to be copied followed by a newline.
End with a backslash and a period on a line by itself.
>> \x3п
>> \.
test=# select length(xx) from test0;length 
--------     1
(1 row)


But on NOT Solaris: 

test=# CREATE TABLE test0 (xx char(2));
CREATE TABLE
test=# copy test0 from stdin;
Enter data to be copied followed by a newline.
End with a backslash and a period on a line by itself.
>> \x3п
>> \.
test=# select length(xx) from test0;length 
--------     2
(1 row)


I'm not sure that everybody will see that code properly due to encoding 
differences. But the idea is just feed postgres with "\x3" and one 
character with the code >128. 



Regards,Sergey

*****************************************************
Sergey E. Koposov
Max-Planck Institut fuer Astronomie
Web: http://lnfm1.sai.msu.ru/~math 
E-mail: math@sai.msu.ru

"Sergey E. Koposov" <math@sai.msu.ru> writes:
> 2660c2660
> <       if (isdigit(hex))
> ---
> >      if (isdigit((unsigned char)hex))

Sigh.  We keep fixing these, and they keep creeping back in.  I wish
there were a way to get some more-mainstream compiler to warn about
passing chars to the <ctype.h> functions.

Thanks for the report.  You only saw the three?
        regards, tom lane

On Thu, 1 Sep 2005, Tom Lane wrote:

> "Sergey E. Koposov" <math@sai.msu.ru> writes:
> > 2660c2660
> > <       if (isdigit(hex))
> > ---
> > >      if (isdigit((unsigned char)hex))
> 
> Sigh.  We keep fixing these, and they keep creeping back in.  I wish
> there were a way to get some more-mainstream compiler to warn about
> passing chars to the <ctype.h> functions.
> 
> Thanks for the report.  You only saw the three?


In fact, I saw two other warnings, but they should not cause any 
problems (at least on my understanding....) :

gcc -O2 -Wall -Wmissing-prototypes -Wpointer-arith -fno-strict-aliasing -DFRONTEND -I. -I../../../src/interfaces/libpq
-I../../../src/include-I/systools/include   -c -o psqlscan.o psqlscan.c
 
In file included from ../../../src/include/c.h:53,                from ../../../src/include/postgres_fe.h:21,
    from psqlscan.l:40:                        
 
../../../src/include/pg_config.h:659:1: warning: "_FILE_OFFSET_BITS" redefined
In file included from /systools/lib/gcc-lib/sparc-sun-solaris2.7/3.2.1/include/stdio.h:36,                from
psqlscan.c:13:                                                     
 
/usr/include/sys/feature_tests.h:96:1: warning: this is the location of the previous definition

XXXXXXXXXXXX

gcc -O2 -Wall -Wmissing-prototypes -Wpointer-arith -fno-strict-aliasing -Wno-error  -I./../include -I.
-I../../../../src/include-I/systools/include  -DMAJOR_VERSION=4 -DMINOR_VERSION=1 -DPATCHLEVEL=1  -c -o preproc.o
preproc.c
In file included from preproc.y:6412:
pgc.c: In function `yylex':
pgc.c:1504: warning: label `find_rule' defined but not used
preproc.y: At top level:
pgc.c:3565: warning: `yy_flex_realloc' defined but not used 


With Best Regards,     Sergey

*****************************************************
Sergey E. Koposov
Max-Planck Institut fuer Astronomie
Web: http://lnfm1.sai.msu.ru/~math 
E-mail: math@sai.msu.ru