OCI_GetStruct calculates incorrect offset when a properly aligned Double is followed by an Int about ocilib

[vrogier]

Hi,

Can you indicate the ocilib version , the oracle version and the platform (32/64bits) ?

The following code (taken from you) give the expected results on Win32/Oracle 12c:

int main()
{
    OCI_Connection* cn;
    OCI_Statement* st;
    OCI_Resultset* rs;

    int i;

    OCI_Initialize(err_handler, NULL, OCI_ENV_DEFAULT);

    cn = OCI_ConnectionCreate("db12c", "usr", "pwd", OCI_SESSION_DEFAULT);
    st = OCI_StatementCreate(cn);

    OCI_ExecuteStmtFmt(st, OTEXT("select val_char_1, val_char_2, val_double, val_long, val_char_3 from test_fetch_struct2"));

    rs = OCI_GetResultset(st);

    OCI_SetStructNumericType(rs, 3, OCI_NUM_DOUBLE);
    OCI_SetStructNumericType(rs, 4, OCI_NUM_INT);

    i = 0;
    while (OCI_FetchNext(rs))
    {
        prd.val_char_1 = 0;
        prd.val_char_2 = 0;
        prd.val_double = 0.0;
        prd.val_long = 0;
        prd.val_char_3 = 0;
        prd.extra = 0;

        OCI_GetStruct(rs, &prd, &ind);
        i++;

        printf("\nrow %d\n", i);
        printf("  > val_char_1 : %08X: %s\n", prd.val_char_1, prd.val_char_1);
        printf("  > val_char_2 : %08X: %s\n", prd.val_char_2, prd.val_char_2);
        printf("  > val_double : %Lf\n", prd.val_double);
        printf("  > val_long : %d\n", prd.val_long);
        printf("  > val_char_3 : %08X %s\n", prd.val_char_3, prd.val_char_3);
        printf("  > extra      : %08X: %s\n", prd.extra, prd.extra);
        printf("\n");
    }

    OCI_Cleanup();

    return EXIT_SUCCESS;
}

the output is :

row 1

val_char_1 : 00203670: col1 row1
val_char_2 : 00203A60: col2 row1
val_double : 123.450000
val_long : 1
val_char_3 : 002044D0 col5 row1
extra : 00000000: (null)

row 2

val_char_1 : 0020368F: col1 row2
val_char_2 : 00203A7F: col2 row2
val_double : 234.560000
val_long : 2
val_char_3 : 002044EF col5 row2
extra : 00000000: (null)

row 3

val_char_1 : 002036AE: col1 row3
val_char_2 : 00203A9E: col2 row3
val_double : 345.670000
val_long : 3
val_char_3 : 0020450E col5 row3
extra : 00000000: (null)

Vincent

[JamesL2]

Changelog.txt: 2015-05-05 Version 4.1.0 Vincent Rogier [email protected]

Using Windows, lib32, ociliba.dll, Oracle 11.2g

#define OCI_CHARSET_ANSI
#define OCI_IMPORT_RUNTIME

[vrogier]

Hi,

Can you try the code I've posted and tell me what results you got ?

Thanks

[JamesL2]

Posted code modified to:
include structure definitions;
create, populate, and delete the oracle table using functions previously posted;
accept connection parameters;
split printing prd.val_char_3 into two statements in order to see the pointer value before attempting to use it.

---

output results:

• test cleanup...
• test setup...

Execute: create table test_fetch_struct2(val_char_1 varchar2(30),val_char_2 varchar2(30),val_double number,val_long number(10),val_char_3 varchar2(30))

Execute: insert into test_fetch_struct2 (val_char_1, val_char_2, val_double, val_long, val_char_3) values ('col1 row1', 'col2 row1', 123.45, 1, 'col5 row1')

Execute: insert into test_fetch_struct2 (val_char_1, val_char_2, val_double, val_long, val_char_3) values ('col1 row1', 'col2 row2', 234.56, 2, 'col5 row2')

Execute: insert into test_fetch_struct2 (val_char_1, val_char_2, val_double, val_long, val_char_3) values ('col1 row1', 'col2 row3', 345.67, 3, 'col5 row3')

row 1

val_char_1 : 009C7FE8: col1 row1
val_char_2 : 009C89C8: col2 row1
val_double : -92559641157289301000000000000000000000000000000000000000000000.000000
val_long : 1079958732
val_char_3 : 00000001

A segment fault (signal 11) occurs attempting to print the string referenced by prd.val_char_3.

---

int main(int argc, oarg* argv[])
{
OCI_Connection* cn = 0;
OCI_Statement* st = 0;
OCI_Resultset* rs = 0;

int i;

// define the structure expected for the retrieval
struct product_t
{
char *val_char_1; // offset 0
char *val_char_2; // offset 4
double val_double; // offset 8 :: column is natually aligned - no adjustment needed
int val_long; // offset 16
char *val_char_3; // offset 20
char *extra; // offset 24 :: don't abend on buffer overflow
} prd;

struct prodind_t
{
    boolean   val_char_1;
    boolean   val_char_2;
    boolean   val_double;
    boolean   val_long;
    boolean   val_char_3;
} ind;

orauser[0] = '\0';
orapswd[0] = '\0';
dbalias[0] = '\0';
orarole[0] = '\0';

GET_ARG(orauser, ARG_USER);
GET_ARG(orapswd, ARG_PWD);
GET_ARG(dbalias, ARG_ALIAS);

OCI_Initialize(err_handler, NULL, OCI_ENV_DEFAULT);

// cn = OCI_ConnectionCreate("db12c", "usr", "pwd", OCI_SESSION_DEFAULT);
if ((cn = OCI_ConnectionCreate(dbalias, orauser, orapswd, OCI_SESSION_DEFAULT)) == NULL)
{
return(1);
}
if ((st = OCI_StatementCreate(cn)) == NULL)
{
return(1);
}

test_cleanup(cn, st, rs);
test_setup(cn, st, rs);

OCI_ExecuteStmtFmt(st, OTEXT("select val_char_1, val_char_2, val_double, val_long, val_char_3 from test_fetch_struct2"));

rs = OCI_GetResultset(st);

OCI_SetStructNumericType(rs, 3, OCI_NUM_DOUBLE);
OCI_SetStructNumericType(rs, 4, OCI_NUM_INT);

i = 0;
while (OCI_FetchNext(rs))
{
    prd.val_char_1 = 0;
    prd.val_char_2 = 0;
    prd.val_double = 0.0;
    prd.val_long = 0;
    prd.val_char_3 = 0;
    prd.extra = 0;

    OCI_GetStruct(rs, &prd, &ind);
    i++;

    printf("\nrow %d\n", i);
    printf("  > val_char_1 : %08X: %s\n", prd.val_char_1, prd.val_char_1);
    printf("  > val_char_2 : %08X: %s\n", prd.val_char_2, prd.val_char_2);
    printf("  > val_double : %Lf\n", prd.val_double);
    printf("  > val_long : %d\n", prd.val_long);
    printf("  > val_char_3 : %08X", prd.val_char_3);
    printf("%s\n", prd.val_char_3);
    printf("  > extra      : %08X: %s\n", prd.extra, prd.extra);
    printf("\n");
}

test_cleanup(cn, st, rs);

OCI_Cleanup();

return EXIT_SUCCESS;

}

[vrogier]

What compiler are you using ?

[JamesL2]

MSVC 2010 generating 32bit executable.
Compiling & executing computer is Windows 7x64 professional & enterprise edition.

[JamesL2]

Print statements added before the fetch loop:

#define PTR_DIFF(ptr1,ptr2) ((long)ptr1 - (long)ptr2)
printf("\nprd column offsets\n");
printf("  > val_char_1 : %08X, %2d\n", &prd.val_char_1, PTR_DIFF(&prd.val_char_1, &prd));
printf("  > val_char_2 : %08X, %2d\n", &prd.val_char_2, PTR_DIFF(&prd.val_char_2, &prd));
printf("  > val_double : %08X, %2d\n", &prd.val_double, PTR_DIFF(&prd.val_double, &prd));
printf("  > val_long   : %08X, %2d\n", &prd.val_long,   PTR_DIFF(&prd.val_long,   &prd));
printf("  > val_char_3 : %08X, %2d\n", &prd.val_char_3, PTR_DIFF(&prd.val_char_3, &prd));
printf("  > extra      : %08X, %2d\n", &prd.extra,      PTR_DIFF(&prd.extra,      &prd));

produces:

prd column offsets
  > val_char_1 : 002EF898,  0
  > val_char_2 : 002EF89C,  4
  > val_double : 002EF8A0,  8
  > val_long   : 002EF8A8, 16
  > val_char_3 : 002EF8AC, 20
  > extra      : 002EF8B0, 24

Print statements added to the OCI_GetStruct function (around the existing ROUNDUP logic):

printf("\nOCI_GetStruct: \n");
:
:
printf("\ti=%3d ptr=%08X size1=%3d align1=%2d size2=%3d align2=%2d", (int)i, ptr, (int)size1, (int)align1, (int)size2, (int)align2);
if (size2 > 0)
{
    size1 = ROUNDUP(size1, align2);
    printf(" size1 roundup: %d", (int)size1);
}
printf("\n");

produces the following, where the 2nd roundup should be 4 instead of 8:

OCI_GetStruct:
    i=  1 ptr=002EF898 size1=  4 align1= 4 size2=  4 align2= 4 size1 roundup: 4
    i=  2 ptr=002EF89C size1=  4 align1= 4 size2=  8 align2= 8 size1 roundup: 8
    i=  3 ptr=002EF8A4 size1=  8 align1= 8 size2=  4 align2= 4 size1 roundup: 8
    i=  4 ptr=002EF8AC size1=  4 align1= 4 size2=  4 align2= 4 size1 roundup: 4
    i=  5 ptr=002EF8B0 size1=  4 align1= 4 size2=  0 align2= 4

[vrogier]

Hi,

You were right indeed. My test and posted code were done using an 64bits build of OCILIB by mistake.
Using a 32bits build, i got the same issues than you.
I've committed a fix for it.
Now on both 32bits and 64bits platforms, results are correct !

Thanks :)

Regards,

Vincent

[vrogier]

Hi,

Is that alright fro you ?

Thanks

Vincent

[JamesL2]

A fix to the issue is good.
Thank you.

While I am not using these functions, I did notice the same logic is used in the OCI_ObjectGetStructSize and OCI_ObjectGetUserStructSize functions, in case they also need an update.