Bug #3260 mysql_prepare fails with a segmentation violation
Submitted: 22 Mar 2004 11:56 Modified: 25 Mar 2004 13:33
Reporter: Matthew Ryan Email Updates:
Status: Not a Bug Impact on me:
None 
Category:MySQL Server Severity:S1 (Critical)
Version:4.1.1 OS:Linux (Redhat 8.0)
Assigned to: Dean Ellis CPU Architecture:Any

[22 Mar 2004 11:56] Matthew Ryan
Description:
mysql_prepare fails with a SIGSEGV signal.  The attached is a slightly modified version of the example for prepared statements API calls.  It used to work, but now crashes every time.

How to repeat:
/* Headers for standard C library routines */
#include <stdlib.h>
#include <stdio.h>
#include <time.h>
#include <string>

#include <mysql.h>
#include <errmsg.h>

#define STRING_SIZE 50

#define SELECT_SAMPLE "SELECT module_key,module_name,timestamp FROM zUtlModule"

int main(int argc, char **argv)
{
MYSQL                     mysql;
MYSQL_STMT    *stmt;
MYSQL_BIND    bind[4];
MYSQL_RES     *prepare_meta_result;
MYSQL_TIME    ts;
unsigned long length[4];
int           param_count, column_count, row_count;
char          small_data[4];
int           int_data;
char          str_data[STRING_SIZE];
my_bool       is_null[4];

  mysql_init(&mysql);
  mysql_options(&mysql,MYSQL_OPT_COMPRESS,0);

/* Prepare a SELECT query to fetch data from test_table */
stmt = mysql_prepare(&mysql, SELECT_SAMPLE, strlen(SELECT_SAMPLE));
if (!stmt)
{
  fprintf(stderr, " mysql_prepare(), SELECT failed\n");
  fprintf(stderr, " %s\n", mysql_error(&mysql));
  exit(0);
}
fprintf(stdout, " prepare, SELECT successful\n");

/* Get the parameter count from the statement */
param_count= mysql_param_count(stmt);
fprintf(stdout, " total parameters in SELECT: %d\n", param_count);

if (param_count != 0) /* validate parameter count */
{
  fprintf(stderr, " invalid parameter count returned by MySQL\n");
  exit(0);
}

/* Fetch result set meta information */
prepare_meta_result = mysql_get_metadata(stmt);
if (!prepare_meta_result)
{
  fprintf(stderr, " mysql_get_metadata(), returned no meta information\n");
  fprintf(stderr, " %s\n", mysql_stmt_error(stmt));
  exit(0);
}

/* Get total columns in the query */
column_count= mysql_num_fields(prepare_meta_result);
fprintf(stdout, " total columns in SELECT statement: %d\n", column_count);

if (column_count != 3) /* validate column count */
{
  fprintf(stderr, " invalid column count returned by MySQL\n");
  exit(0);
}

/* Execute the SELECT query */
if (mysql_execute(stmt))
{
  fprintf(stderr, " mysql_execute(), failed\n");
  fprintf(stderr, " %s\n", mysql_stmt_error(stmt));
  exit(0);
}

/* Bind the result buffers for all 4 columns before fetching them */

/* INTEGER COLUMN */
bind[0].buffer_type= MYSQL_TYPE_LONG;
bind[0].buffer= (char *)&int_data;
bind[0].is_null= &is_null[0];
bind[0].length= &length[0];

/* STRING COLUMN */
bind[1].buffer_type= MYSQL_TYPE_VAR_STRING;
bind[1].buffer= (char *)str_data;
bind[1].buffer_length= STRING_SIZE;
bind[1].is_null= &is_null[1];
bind[1].length= &length[1];
 
/* TIMESTAMP COLUMN */
bind[3].buffer_type= MYSQL_TYPE_TIMESTAMP;
bind[3].buffer= (char *)&ts;       
bind[3].is_null= &is_null[3];
bind[3].length= &length[3];

/* Bind the result buffers */
if (mysql_bind_result(stmt, bind))
{
  fprintf(stderr, " mysql_bind_result() failed\n");
  fprintf(stderr, " %s\n", mysql_stmt_error(stmt));
  exit(0);
}

/* Now buffer all results to client */
if (mysql_stmt_store_result(stmt))
{
  fprintf(stderr, " mysql_stmt_store_result() failed\n");
  fprintf(stderr, " %s\n", mysql_stmt_error(stmt));
  exit(0);
}

/* Fetch all rows */
row_count= 0;
fprintf(stdout, "Fetching results ...\n");
while (!mysql_fetch(stmt))
{
  row_count++;
  fprintf(stdout, "  row %d\n", row_count);

  /* column 1 */
  fprintf(stdout, "   column1 (integer)  : ");
  if (is_null[0])
    fprintf(stdout, " NULL\n");
  else
    fprintf(stdout, " %d(%ld)\n", int_data, length[0]);

  /* column 2 */
  fprintf(stdout, "   column2 (string)   : ");
  if (is_null[1])
    fprintf(stdout, " NULL\n");
  else
    fprintf(stdout, " %s(%ld)\n", str_data, length[1]);

  /* column 4 */
  fprintf(stdout, "   column4 (timestamp): ");
  if (is_null[3])
    fprintf(stdout, " NULL\n");
  else
    fprintf(stdout, " %04d-%02d-%02d %02d:%02d:%02d (%ld)\n",
                                               ts.year, ts.month, ts.day,
                                               ts.hour, ts.minute, ts.second,
                                               length[3]);
  fprintf(stdout, "\n");
}

/* Validate rows fetched */
fprintf(stdout, " total rows fetched: %d\n", row_count);

/* Free the prepared result metadata */
mysql_free_result(prepare_meta_result);

/* Close the statement */
if (mysql_stmt_close(stmt))
{
  fprintf(stderr, " failed while closing the statement\n");
  fprintf(stderr, " %s\n", mysql_stmt_error(stmt));
  exit(0);
}

}
[25 Mar 2004 13:33] Dean Ellis
This is because you are not connecting to a server.