mod_dbd.c

apache服务器源代码（版本号：2.2.2）

/* Copyright 2003-6 The Apache Software Foundation or its licensors, as
 * applicable.
 *
 * Licensed 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.
 */

/* Overview of what this is and does:
 * http://www.apache.org/~niq/dbd.html
 * or
 * http://apache.webthing.com/database/
 */

#include <ctype.h>

#include "http_protocol.h"
#include "http_config.h"
#include "http_log.h"
#include "apr_reslist.h"
#include "apr_strings.h"
#include "apr_dbd.h"
#include "mod_dbd.h"

extern module AP_MODULE_DECLARE_DATA dbd_module;

/************ svr cfg: manage db connection pool ****************/

#define NMIN_SET     0x1
#define NKEEP_SET    0x2
#define NMAX_SET     0x4
#define EXPTIME_SET  0x8

typedef struct dbd_prepared {
    const char *label;
    const char *query;
    struct dbd_prepared *next;
} dbd_prepared;
typedef struct svr_cfg {
    const char *name;
    const char *params;
    int persist;
    dbd_prepared *prepared;
#if APR_HAS_THREADS
    apr_thread_mutex_t *mutex;
    apr_pool_t *pool;
    apr_reslist_t *dbpool;
    int nmin;
    int nkeep;
    int nmax;
    int exptime;
#else
    ap_dbd_t *conn;
#endif
    unsigned int set;
} svr_cfg;

typedef enum { cmd_name, cmd_params, cmd_persist,
               cmd_min, cmd_keep, cmd_max, cmd_exp
} cmd_parts;


#define ISINT(val) \
        for (p = val; *p; ++p)        \
                if (!isdigit(*p))        \
                        return "Argument must be numeric!"
static const char *dbd_param(cmd_parms *cmd, void *cfg, const char *val)
{
    const char *p;
    const apr_dbd_driver_t *driver = NULL;
    svr_cfg *svr = (svr_cfg*) ap_get_module_config
        (cmd->server->module_config, &dbd_module);

    switch ((long) cmd->info) {
    case cmd_name:
        svr->name = val;
        /* loading the driver involves once-only dlloading that is
         * best done at server startup.  This also guarantees that
         * we won't return an error later.
         */
        switch (apr_dbd_get_driver(cmd->pool, svr->name, &driver)) {
        case APR_ENOTIMPL:
            return apr_psprintf(cmd->pool, "DBD: No driver for %s", svr->name);
        case APR_EDSOOPEN:
            return apr_psprintf(cmd->pool,
                                "DBD: Can't load driver file apr_dbd_%s.so",
                                svr->name);
        case APR_ESYMNOTFOUND:
            return apr_psprintf(cmd->pool,
                                "DBD: Failed to load driver apr_dbd_%s_driver",
                                svr->name);
        }
        break;
    case cmd_params:
        svr->params = val;
        break;
#if APR_HAS_THREADS
    case cmd_min:
        ISINT(val);
        svr->nmin = atoi(val);
        svr->set |= NMIN_SET;
        break;
    case cmd_keep:
        ISINT(val);
        svr->nkeep = atoi(val);
        svr->set |= NKEEP_SET;
        break;
    case cmd_max:
        ISINT(val);
        svr->nmax = atoi(val);
        svr->set |= NMAX_SET;
        break;
    case cmd_exp:
        ISINT(val);
        svr->exptime = atoi(val);
        svr->set |= EXPTIME_SET;
        break;
#endif
    }
    return NULL;
}
static const char *dbd_param_flag(cmd_parms *cmd, void *cfg, int flag)
{
    svr_cfg *svr = (svr_cfg*) ap_get_module_config
        (cmd->server->module_config, &dbd_module);

    switch ((long) cmd->info) {
    case cmd_persist:
        svr->persist = flag;
        break;
    }
    return NULL;
}
DBD_DECLARE_NONSTD(void) ap_dbd_prepare(server_rec *s, const char *query,
                                        const char *label)
{
    svr_cfg *svr = ap_get_module_config(s->module_config, &dbd_module);
    dbd_prepared *prepared = apr_pcalloc(s->process->pool, sizeof(dbd_prepared));
    prepared->label = label;
    prepared->query = query;
    prepared->next = svr->prepared;
    svr->prepared = prepared;
}
static const char *dbd_prepare(cmd_parms *cmd, void *cfg, const char *query,
                               const char *label)
{
    ap_dbd_prepare(cmd->server, query, label);
    return NULL;
}
static const command_rec dbd_cmds[] = {
    AP_INIT_TAKE1("DBDriver", dbd_param, (void*)cmd_name, RSRC_CONF,
                  "SQL Driver"),
    AP_INIT_TAKE1("DBDParams", dbd_param, (void*)cmd_params, RSRC_CONF,
                  "SQL Driver Params"),
    AP_INIT_FLAG("DBDPersist", dbd_param_flag, (void*)cmd_persist, RSRC_CONF,
                 "Use persistent connection/pool"),
    AP_INIT_TAKE2("DBDPrepareSQL", dbd_prepare, NULL, RSRC_CONF,
                  "Prepared SQL statement, label"),
#if APR_HAS_THREADS
    AP_INIT_TAKE1("DBDMin", dbd_param, (void*)cmd_min, RSRC_CONF,
                  "Minimum number of connections"),
    /* XXX: note that mod_proxy calls this "smax" */
    AP_INIT_TAKE1("DBDKeep", dbd_param, (void*)cmd_keep, RSRC_CONF,
                  "Maximum number of sustained connections"),
    AP_INIT_TAKE1("DBDMax", dbd_param, (void*)cmd_max, RSRC_CONF,
                  "Maximum number of connections"),
    /* XXX: note that mod_proxy calls this "ttl" (time to live) */
    AP_INIT_TAKE1("DBDExptime", dbd_param, (void*)cmd_exp, RSRC_CONF,
                  "Keepalive time for idle connections"),
#endif
    {NULL}
};
static void *dbd_merge(apr_pool_t *pool, void *BASE, void *ADD) {
    svr_cfg *base = (svr_cfg*) BASE;
    svr_cfg *add = (svr_cfg*) ADD;
    svr_cfg *cfg = apr_pcalloc(pool, sizeof(svr_cfg));
    cfg->name = strcmp(add->name, "") ? add->name : base->name;
    cfg->params = strcmp(add->params, "") ? add->params : base->params;
    cfg->persist = (add->persist == -1) ? base->persist : add->persist;
#if APR_HAS_THREADS
    cfg->nmin = (add->set&NMIN_SET) ? add->nmin : base->nmin;
    cfg->nkeep = (add->set&NKEEP_SET) ? add->nkeep : base->nkeep;
    cfg->nmax = (add->set&NMAX_SET) ? add->nmax : base->nmax;
    cfg->exptime = (add->set&EXPTIME_SET) ? add->exptime : base->exptime;
#endif
    cfg->set = add->set | base->set;
    return (void*) cfg;
}
/* A default nmin of >0 will help with generating meaningful
 * startup error messages if the database is down.
 */
#define DEFAULT_NMIN 1
#define DEFAULT_NKEEP 2
#define DEFAULT_NMAX 10
#define DEFAULT_EXPTIME 300
static void *dbd_cfg(apr_pool_t *p, server_rec *x)
{
    svr_cfg *svr = (svr_cfg*) apr_pcalloc(p, sizeof(svr_cfg));
    svr->name = svr->params = ""; /* don't risk segfault on misconfiguration */
    svr->persist = -1;
#if APR_HAS_THREADS
    svr->nmin = DEFAULT_NMIN;
    svr->nkeep = DEFAULT_NKEEP;
    svr->nmax = DEFAULT_NMAX;
    svr->exptime = DEFAULT_EXPTIME;
#endif
    return svr;
}
static apr_status_t dbd_prepared_init(apr_pool_t *pool, svr_cfg *svr,
                                      ap_dbd_t *dbd)
{
    dbd_prepared *p;
    apr_status_t ret = APR_SUCCESS;
    apr_dbd_prepared_t *stmt;
    dbd->prepared = apr_hash_make(pool);

    for (p = svr->prepared; p; p = p->next) {
        stmt = NULL;
        if (apr_dbd_prepare(dbd->driver, pool, dbd->handle, p->query,
                            p->label, &stmt) == 0) {
            apr_hash_set(dbd->prepared, p->label, APR_HASH_KEY_STRING, stmt);
        }
        else {
            ret = APR_EGENERAL;
        }
    }
    return ret;
}
/************ svr cfg: manage db connection pool ****************/
/* an apr_reslist_constructor for SQL connections
 * Also use this for opening in non-reslist modes, since it gives
 * us all the error-handling in one place.
 */
static apr_status_t dbd_construct(void **db, void *params, apr_pool_t *pool)
{
    svr_cfg *svr = (svr_cfg*) params;
    ap_dbd_t *rec = apr_pcalloc(pool, sizeof(ap_dbd_t));
    apr_status_t rv;

    /* this pool is mostly so dbd_close can destroy the prepared stmts */
    rv = apr_pool_create(&rec->pool, pool);
    if (rv != APR_SUCCESS) {
        ap_log_perror(APLOG_MARK, APLOG_CRIT, rv, pool,
                      "DBD: Failed to create memory pool");
    }

/* The driver is loaded at config time now, so this just checks a hash.
 * If that changes, the driver DSO could be registered to unload against
 * our pool, which is probably not what we want.  Error checking isn't
 * necessary now, but in case that changes in the future ...
 */
    rv = apr_dbd_get_driver(rec->pool, svr->name, &rec->driver);
    switch (rv) {
    case APR_ENOTIMPL:
        ap_log_perror(APLOG_MARK, APLOG_CRIT, rv, rec->pool,
                      "DBD: driver for %s not available", svr->name);
        return rv;
    case APR_EDSOOPEN:
        ap_log_perror(APLOG_MARK, APLOG_CRIT, rv, rec->pool,
                      "DBD: can't find driver for %s", svr->name);
        return rv;
    case APR_ESYMNOTFOUND:
        ap_log_perror(APLOG_MARK, APLOG_CRIT, rv, rec->pool,
                      "DBD: driver for %s is invalid or corrupted", svr->name);
        return rv;
    default:
        ap_log_perror(APLOG_MARK, APLOG_CRIT, rv, rec->pool,
                      "DBD: mod_dbd not compatible with apr in get_driver");
        return rv;
    case APR_SUCCESS:
        break;
    }

    rv = apr_dbd_open(rec->driver, rec->pool, svr->params, &rec->handle);
    switch (rv) {
    case APR_EGENERAL:
        ap_log_perror(APLOG_MARK, APLOG_CRIT, rv, rec->pool,
                      "DBD: Can't connect to %s", svr->name);
        return rv;
    default:
        ap_log_perror(APLOG_MARK, APLOG_CRIT, rv, rec->pool,
                      "DBD: mod_dbd not compatible with apr in open");
        return rv;
    case APR_SUCCESS:
        break;
    }
    *db = rec;
    rv = dbd_prepared_init(rec->pool, svr, rec);
    if (rv != APR_SUCCESS) {
        ap_log_perror(APLOG_MARK, APLOG_CRIT, rv, rec->pool,
                      "DBD: failed to initialise prepared SQL statements");
    }
    return rv;
}
static apr_status_t dbd_close(void *CONN)
{
    ap_dbd_t *conn = CONN;
    apr_status_t rv = apr_dbd_close(conn->driver, conn->handle);
    apr_pool_destroy(conn->pool);
    return rv;
}
#if APR_HAS_THREADS
static apr_status_t dbd_destruct(void *sql, void *params, apr_pool_t *pool)
{