apr_dbd_oracle.c

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/* Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/* Developed initially by Nick Kew and Chris Darroch.
 * Contributed to the APR project by kind permission of
 * Pearson Education Core Technology Group (CTG),
 * formerly Central Media Group (CMG).
 */

/* apr_dbd_oracle - a painful attempt
 *
 * Based first on the documentation at
 * http://download-west.oracle.com/docs/cd/B10501_01/appdev.920/a96584/toc.htm
 *
 * Those docs have a lot of internal inconsistencies, contradictions, etc
 * So I've snarfed the demo programs (from Oracle 8, not included in
 * the current downloadable oracle), and used code from them.
 *
 * Why do cdemo81.c and cdemo82.c do the same thing in very different ways?
 * e.g. cdemo82 releases all its handle on shutdown; cdemo81 doesn't
 *
 * All the ORA* functions return a "sword".  Some of them are documented;
 * others aren't.  So I've adopted a policy of using switch statements
 * everywhere, even when we're not doing anything with the return values.
 *
 * This makes no attempt at performance tuning, such as setting
 * prefetch cache size.  We need some actual performance data
 * to make that meaningful.  Input from someone with experience
 * as a sysop using oracle would be a good start.
 */

/* shut compiler up */
#ifdef DEBUG
#define int_errorcode int errorcode
#else
#define int_errorcode
#endif

#include "apu.h"

#if APU_HAVE_ORACLE

#include <ctype.h>
#include <stdlib.h>
#include <stdio.h>

#include <oci.h>

#include "apr_strings.h"
#include "apr_time.h"
#include "apr_hash.h"
#include "apr_buckets.h"

#define TRANS_TIMEOUT 30
#define MAX_ARG_LEN 256 /* in line with other apr_dbd drivers.  We alloc this
                         * lots of times, so a large value gets hungry.
                         * Should really make it configurable
                         */
#define DEFAULT_LONG_SIZE 4096
#define DBD_ORACLE_MAX_COLUMNS 256
#define NUMERIC_FIELD_SIZE 32

#define CHECK_CONN_QUERY "SELECT 1 FROM dual"

#define ERR_BUF_SIZE 200

#ifdef DEBUG
#include <stdio.h>
#endif

#include "apr_dbd_internal.h"

/* declarations */
static const char *dbd_oracle_error(apr_dbd_t *sql, int n);
static int dbd_oracle_prepare(apr_pool_t *pool, apr_dbd_t *sql,
                              const char *query, const char *label,
                              int nargs, int nvals, apr_dbd_type_e *types,
                              apr_dbd_prepared_t **statement);
static int outputParams(apr_dbd_t*, apr_dbd_prepared_t*);
static int dbd_oracle_pselect(apr_pool_t *pool, apr_dbd_t *sql,
                              apr_dbd_results_t **results,
                              apr_dbd_prepared_t *statement,
                              int seek, const char **values);
static int dbd_oracle_pquery(apr_pool_t *pool, apr_dbd_t *sql,
                             int *nrows, apr_dbd_prepared_t *statement,
                             const char **values);
static int dbd_oracle_start_transaction(apr_pool_t *pool, apr_dbd_t *sql,
                                        apr_dbd_transaction_t **trans);
static int dbd_oracle_end_transaction(apr_dbd_transaction_t *trans);

struct apr_dbd_transaction_t {
    int mode;
    enum { TRANS_NONE, TRANS_ERROR, TRANS_1, TRANS_2 } status;
    apr_dbd_t *handle;
    OCITrans *trans;
    OCISnapshot *snapshot1;
    OCISnapshot *snapshot2;
};

struct apr_dbd_results_t {
    apr_pool_t *pool;
    apr_dbd_t* handle;
    unsigned int rownum;
    int seek;
    int nrows;
    apr_dbd_prepared_t *statement;
};

struct apr_dbd_t {
    sword status;
    OCIError *err;
    OCIServer *svr;
    OCISvcCtx *svc;
    OCISession *auth;
    apr_dbd_transaction_t* trans;
    apr_pool_t *pool;
    char buf[ERR_BUF_SIZE]; /* for error messages */
    apr_size_t long_size;
    apr_dbd_prepared_t *check_conn_stmt;
};

struct apr_dbd_row_t {
    int n;
    apr_dbd_results_t *res;
    apr_pool_t *pool;
};

typedef struct {
    apr_dbd_type_e type;
    sb2 ind;
    sb4 len;
    OCIBind *bind;
    union {
        void *raw;
        char *sval;
        int ival;
        unsigned int uval;
        double fval;
        OCILobLocator *lobval;
    } value;
} bind_arg;

typedef struct {
    int type;
    sb2 ind;
    ub2 len;         /* length of actual output */
    OCIDefine *defn;
    apr_size_t sz;   /* length of buf for output */
    union {
        void *raw;
        char *sval;
        OCILobLocator *lobval;
    } buf;
    const char *name;
} define_arg;

struct apr_dbd_prepared_t {
    OCIStmt *stmt;
    int nargs;
    int nvals;
    bind_arg *args;
    int nout;
    define_arg *out;
    apr_dbd_t *handle;
    apr_pool_t *pool;
    int type;
};

/* AFAICT from the docs, the OCIEnv thingey can be used async
 * across threads, so lets have a global one.
 *
 * We'll need shorter-lived envs to deal with requests and connections
 *
 * Hmmm, that doesn't work: we don't have a usermem framework.
 * OK, forget about using APR pools here, until we figure out
 * the right way to do it (if such a thing exists).
 */
static OCIEnv *dbd_oracle_env = NULL;

/* Oracle specific bucket for BLOB/CLOB types */
typedef struct apr_bucket_lob apr_bucket_lob;
/**
 * A bucket referring to a Oracle BLOB/CLOB
 */
struct apr_bucket_lob {
    /** Number of buckets using this memory */
    apr_bucket_refcount  refcount;
    /** The row this bucket refers to */
    const apr_dbd_row_t *row;
    /** The column this bucket refers to */
    int col;
    /** The pool into which any needed structures should
     *  be created while reading from this bucket */
    apr_pool_t *readpool;
};

static void lob_bucket_destroy(void *data);
static apr_status_t lob_bucket_read(apr_bucket *e, const char **str,
                                    apr_size_t *len, apr_read_type_e block);
static apr_bucket *apr_bucket_lob_make(apr_bucket *b,
                                       const apr_dbd_row_t *row, int col,
                                       apr_off_t offset, apr_size_t len,
                                       apr_pool_t *p);
static apr_bucket *apr_bucket_lob_create(const apr_dbd_row_t *row, int col,
                                         apr_off_t offset,
                                         apr_size_t len, apr_pool_t *p,
                                         apr_bucket_alloc_t *list);

static const apr_bucket_type_t apr_bucket_type_lob = {
    "LOB", 5, APR_BUCKET_DATA,
    lob_bucket_destroy,
    lob_bucket_read,
    apr_bucket_setaside_notimpl,
    apr_bucket_shared_split,
    apr_bucket_shared_copy
};

static void lob_bucket_destroy(void *data)
{
    apr_bucket_lob *f = data;

    if (apr_bucket_shared_destroy(f)) {
        /* no need to destroy database objects here; it will get
         * done automatically when the pool gets cleaned up */
        apr_bucket_free(f);
    }
}

static apr_status_t lob_bucket_read(apr_bucket *e, const char **str,
                                    apr_size_t *len, apr_read_type_e block)
{
    apr_bucket_lob *a = e->data;
    const apr_dbd_row_t *row = a->row;
    apr_dbd_results_t *res = row->res;
    int col = a->col;
    apr_bucket *b = NULL;
    apr_size_t blength = e->length;  /* bytes remaining in file past offset */
    apr_off_t boffset = e->start;
    define_arg *val = &res->statement->out[col];
    apr_dbd_t *sql = res->handle;
/* Only with 10g, unfortunately
    oraub8 length = APR_BUCKET_BUFF_SIZE;
*/
    ub4 length = APR_BUCKET_BUFF_SIZE;
    char *buf = NULL;

    *str = NULL;  /* in case we die prematurely */

    /* fetch from offset if not at the beginning */
    buf = apr_palloc(row->pool, APR_BUCKET_BUFF_SIZE);
    sql->status = OCILobRead(sql->svc, sql->err, val->buf.lobval,
                             &length, 1 + boffset,
                             (dvoid*) buf, APR_BUCKET_BUFF_SIZE,
                             NULL, NULL, 0, SQLCS_IMPLICIT);
/* Only with 10g, unfortunately
    sql->status = OCILobRead2(sql->svc, sql->err, val->buf.lobval,
                              &length, NULL, 1 + boffset,
                              (dvoid*) buf, APR_BUCKET_BUFF_SIZE,
                              OCI_ONE_PIECE, NULL, NULL, 0, SQLCS_IMPLICIT);
*/
    if (sql->status != OCI_SUCCESS) {
        return APR_EGENERAL;
    }
    blength -= length;
    *len = length;
    *str = buf;

    /*
     * Change the current bucket to refer to what we read,
     * even if we read nothing because we hit EOF.
     */
    apr_bucket_pool_make(e, *str, *len, res->pool);

    /* If we have more to read from the field, then create another bucket */
    if (blength > 0) {
        /* for efficiency, we can just build a new apr_bucket struct
         * to wrap around the existing LOB bucket */
        b = apr_bucket_alloc(sizeof(*b), e->list);
        b->start  = boffset + *len;
        b->length = blength;
        b->data   = a;
        b->type   = &apr_bucket_type_lob;
        b->free   = apr_bucket_free;
        b->list   = e->list;
        APR_BUCKET_INSERT_AFTER(e, b);
    }
    else {
        lob_bucket_destroy(a);
    }

    return APR_SUCCESS;
}

static apr_bucket *apr_bucket_lob_make(apr_bucket *b,
                                       const apr_dbd_row_t *row, int col,
                                       apr_off_t offset, apr_size_t len,
                                       apr_pool_t *p)
{
    apr_bucket_lob *f;

    f = apr_bucket_alloc(sizeof(*f), b->list);
    f->row = row;
    f->col = col;
    f->readpool = p;

    b = apr_bucket_shared_make(b, f, offset, len);
    b->type = &apr_bucket_type_lob;

    return b;
}

static apr_bucket *apr_bucket_lob_create(const apr_dbd_row_t *row, int col,
                                         apr_off_t offset,
                                         apr_size_t len, apr_pool_t *p,
                                         apr_bucket_alloc_t *list)
{
    apr_bucket *b = apr_bucket_alloc(sizeof(*b), list);

    APR_BUCKET_INIT(b);
    b->free = apr_bucket_free;
    b->list = list;
    return apr_bucket_lob_make(b, row, col, offset, len, p);
}

static apr_status_t dbd_free_lobdesc(void *lob)
{
    switch (OCIDescriptorFree(lob, OCI_DTYPE_LOB)) {
    case OCI_SUCCESS:
        return APR_SUCCESS;
    default:
        return APR_EGENERAL;
    }
}

static apr_status_t dbd_free_snapshot(void *snap)
{
    switch (OCIDescriptorFree(snap, OCI_DTYPE_SNAP)) {
    case OCI_SUCCESS:
        return APR_SUCCESS;
    default:
        return APR_EGENERAL;
    }
}

static void dbd_oracle_init(apr_pool_t *pool)
{
    if (dbd_oracle_env == NULL) {
        /* Sadly, OCI_SHARED seems to be impossible to use, due to
         * various Oracle bugs.  See, for example, Oracle MetaLink bug 2972890
         * and PHP bug http://bugs.php.net/bug.php?id=23733
         */
#ifdef OCI_NEW_LENGTH_SEMANTICS
        OCIEnvCreate(&dbd_oracle_env, OCI_THREADED|OCI_NEW_LENGTH_SEMANTICS,
                     NULL, NULL, NULL, NULL, 0, NULL);
#else
        OCIEnvCreate(&dbd_oracle_env, OCI_THREADED,
                     NULL, NULL, NULL, NULL, 0, NULL);
#endif
    }
}

static apr_dbd_t *dbd_oracle_open(apr_pool_t *pool, const char *params,
                                  const char **error)
{
    apr_dbd_t *ret = apr_pcalloc(pool, sizeof(apr_dbd_t));
    int errorcode;

    char *BLANK = "";
    struct {
        const char *field;
        char *value;