[bug fix] ECPG app crashes due to SIGBUS on SPARC Solaris

Hello,

I encountered a bug of ECPG with PG 9.2.4, which probably exists in all
releases.  The attached patch is for 9.4.  Could you review and backport
this to at least 9.2 and later?


[Problem]
The attached ECPG app crashes and dumps core with SIGBUS on Solaris for
SPARC.  I used Solaris 10, and Oracle Studio to compile the app for 64-bit
build.  The same app completes successfully on Linux and Windows for
x86/x564.

The steps to reproduce the problem is:
1. ecpg sigbus.pgc
2. cc -xtarget=generic64 -I<pgsql_dir>/include
sigbus.c -L<pgsql_dir>/lib -lecpg
3. a.out

When execting FETCH statement using an SQL descriptor, the app crashes at
the following line in ECPGdo(), which is in
src/interfaces/ecpg/ecpglib/execute.c:

    var->value = *((char **) (var->pointer));


[Cause]
ecpg outputs the following line in the preprocessed source file:

 { ECPGdo(__LINE__, 0, 1, NULL, 0, ECPGst_normal, "fetch $0",
 ECPGt_char,(cur),(long)4,(long)1,(4)*sizeof(char),
 ECPGt_NO_INDICATOR, NULL , 0L, 0L, 0L, ECPGt_EOIT,
 ECPGt_descriptor, (desc1), 0L, 0L, 0L,
 ECPGt_NO_INDICATOR, NULL , 0L, 0L, 0L, ECPGt_EORT);}

So, the above line is executed in ECPGdo().  On the other hand, desc1 is not
aligned on 8-byte boundary.  This unaligned access causes SIGBUS.


[Fix]
Because desc1 is a char array, else block should be executed instead of the
above path.

    var->value = var->pointer;

Therefore, make ecpg pass SQL descriptor host variables to ECPGdo() with
non-zero lengths.


Regards
MauMau