OCI_GetStruct calculates incorrect offset when a properly aligned Double is followed by an Int #12
Comments
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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
row 2
row 3
Vincent |
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Changelog.txt: 2015-05-05 Version 4.1.0 Vincent Rogier vince.rogier@ocilib.net Using Windows, lib32, ociliba.dll, Oracle 11.2g #define OCI_CHARSET_ANSI |
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Hi, Can you try the code I've posted and tell me what results you got ? Thanks |
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Posted code modified to: output results:
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
A segment fault (signal 11) occurs attempting to print the string referenced by prd.val_char_3. int main(int argc, oarg* argv[]) // define the structure expected for the retrieval // cn = OCI_ConnectionCreate("db12c", "usr", "pwd", OCI_SESSION_DEFAULT); } |
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What compiler are you using ? |
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MSVC 2010 generating 32bit executable. |
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Print statements added before the fetch loop: produces: Print statements added to the OCI_GetStruct function (around the existing ROUNDUP logic): produces the following, where the 2nd roundup should be 4 instead of 8: |
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Hi, You were right indeed. My test and posted code were done using an 64bits build of OCILIB by mistake. Thanks :) Regards, Vincent |
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Hi, Is that alright fro you ? Thanks Vincent |
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A fix to the issue is good. 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. |
The existing OCI_GetStruct alignment calculation needs to be updated.
Summary:
For the table:
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));
Expected C structure:
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;
Actual C structure needed for OCI_GetStruct:
struct product2_t
{
char *val_char_1; // offset 0
char *val_char_2; // offset 4
char *bad_align; // offset 8 :: structure alignment calculation is skipping 4 extra bytes
float val_double; // offset 12 :: cheat to get the alignment being calculated
float val_double2; // offset 16
int val_long; // offset 20
char *val_char_3; // offset 24
char *extra; // offset 28 :: don't abend on buffer overflow
} prd2;
Details:
New OCI_GetStruct function:
/* --------------------------------------------------------------------------------------------- *
boolean OCI_API OCI_GetStructNew
(
OCI_Resultset *rs,
void *row_struct,
void *row_struct_ind
)
{
char *ptr = NULL;
boolean *inds = NULL;
// size_t alignForMax = 0;
// ptr should start at a proper double (8 byte) alignment
if (ptr)
{
size_t structSize = 0;
size_t size1 = 0;
size_t align1 = 0;
ub4 i;
// if (alignForMax < align1)
// {
// alignForMax = align1; // remember the largest alignment for this structure
// }
// if (alignForMax)
// {
// alignOffset = ptr % alignForMax; // how far off is the alignment?
// if (alignOffset)
// {
// ptr += (alignForMax - alignOffset); // adjust the pointer for this field
// }
// }
}
}
Test Code:
/*-----------
test_setup
-----------/
int test_setup (OCI_Connection *ociConn, OCI_Statement *ociStmt, OCI_Resultset *ociRset)
{
int retval = 0;
otext *sqlString;
prnlog("\n- test setup...\n");
sqlString = OTEXT("create table test_fetch_struct2")
OTEXT("(val_char_1 varchar2(30)")
OTEXT(",val_char_2 varchar2(30)")
OTEXT(",val_double number")
OTEXT(",val_long number(10)")
OTEXT(",val_char_3 varchar2(30)")
OTEXT(")")
;
prnlog("\nExecute: %s\n", sqlString);
OCI_ExecuteStmt(ociStmt, sqlString);
sqlString = OTEXT("insert into test_fetch_struct2 (val_char_1, val_char_2, val_double, val_long, val_char_3) ")
OTEXT("values ('col1 row1', 'col2 row1', 123.45, 1, 'col5 row1')")
;
prnlog("\nExecute: %s\n", sqlString);
OCI_ExecuteStmt(ociStmt, sqlString);
sqlString = OTEXT("insert into test_fetch_struct2 (val_char_1, val_char_2, val_double, val_long, val_char_3) ")
OTEXT("values ('col1 row1', 'col2 row2', 234.56, 2, 'col5 row2')")
;
prnlog("\nExecute: %s\n", sqlString);
OCI_ExecuteStmt(ociStmt, sqlString);
sqlString = OTEXT("insert into test_fetch_struct2 (val_char_1, val_char_2, val_double, val_long, val_char_3) ")
OTEXT("values ('col1 row1', 'col2 row3', 345.67, 3, 'col5 row3')")
;
prnlog("\nExecute: %s\n", sqlString);
OCI_ExecuteStmt(ociStmt, sqlString);
OCI_Commit(ociConn);
OCI_ReleaseResultsets(ociStmt);
return(retval);
}
/*-------------
test cleanup
-------------/
int test_cleanup (OCI_Connection *ociConn, OCI_Statement *ociStmt, OCI_Resultset *ociRset)
{
int retval = 0;
prnlog("\n- test cleanup...\n");
oci_nofail = 1; /* ignore errors */
OCI_ExecuteStmt(ociStmt, OTEXT("drop table test_fetch_struct2"));
OCI_ReleaseResultsets(ociStmt);
oci_nofail = 0;
return(retval);
}
/*------------------
------------------/
int test_fetch_struct_bad (OCI_Connection *ociConn, OCI_Statement *ociStmt, OCI_Resultset *ociRset)
{
int retval = 0;
int iCnt;
// 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;
// define the structure as mapped by the OCI_GetStruct function
struct product2_t
{
char *val_char_1; // offset 0
char *val_char_2; // offset 4
char *bad_align; // offset 8 :: structure alignment calculation is skipping 4 extra bytes
float val_double; // offset 12 :: cheat to get the alignment being calculated
float val_double2; // offset 16
int val_long; // offset 20
char *val_char_3; // offset 24
char *extra; // offset 28 :: don't abend on buffer overflow
} prd2;
// //////////////////////////
}
/*------------------
test_fetch_struct
------------------/
int test_fetch_struct_new (OCI_Connection *ociConn, OCI_Statement *ociStmt, OCI_Resultset *ociRset)
{
int retval = 0;
int iCnt;
struct product_t
{
char *val_char_1; // offset 0
char *val_char_2; // offset 4
double val_double; // offset 8
int val_long; // offset 16
char *val_char_3; // offset 20
char *extra; // don't abend on overflow
} prd;
struct prodind_t
{
boolean val_char_1;
boolean val_char_2;
boolean val_double;
boolean val_long;
boolean val_char_3;
} ind;
prnlog("\n- test fetch struct new: prd...\n"
" This shows the structure properly mapped by the updated logic\n");
OCI_ExecuteStmtFmt(ociStmt, OTEXT("select val_char_1, val_char_2, val_double, val_long, val_char_3 from test_fetch_struct2"));
ociRset = OCI_GetResultset(ociStmt);
OCI_SetStructNumericType(ociRset, 3, OCI_NUM_DOUBLE);
OCI_SetStructNumericType(ociRset, 4, OCI_NUM_INT);
iCnt = 0;
while (OCI_FetchNext(ociRset))
{
prd.extra = 0;
}
prnlog(" + %d row(s) fetched\n", OCI_GetRowCount(ociRset));
OCI_ReleaseResultsets(ociStmt);
retval = oci_rc;
return(retval);
}
Test output:
OCI Test
Oracle User : xxxxxxxx
Oracle DBName : myOraDB
Connect Role :
INFO-ORA-00942: table or view does not exist
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')
This shows the val_long, and val_char_3, values shifted to the next column
row 1
row 2
row 3
This shows the structure as mapped by the OCI_GetStruct logic
row 1
row 2
row 3
This shows the structure properly mapped by the updated logic
row 1
row 2
row 3
OCILib Errors = 0
Oracle Errors = 0
Oracle Warnings= 0
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