mod_dbd.c

linux网络服务器工具

/* 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.
 */

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

#include "apr_reslist.h"
#include "apr_strings.h"
#include "apr_hash.h"
#include "apr_tables.h"
#include "apr_lib.h"
#include "apr_dbd.h"

#define APR_WANT_MEMFUNC
#define APR_WANT_STRFUNC
#include "apr_want.h"

#include "http_protocol.h"
#include "http_config.h"
#include "http_log.h"
#include "http_request.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 {
    server_rec *server;
    const char *name;
    const char *params;
    int persist;
#if APR_HAS_THREADS
    int nmin;
    int nkeep;
    int nmax;
    int exptime;
    int set;
#endif
    apr_hash_t *queries;
} dbd_cfg_t;

typedef struct dbd_group_t dbd_group_t;

struct dbd_group_t {
    dbd_cfg_t *cfg;
    dbd_group_t *next;
    apr_pool_t *pool;
#if APR_HAS_THREADS
    apr_thread_mutex_t *mutex;
    apr_reslist_t *reslist;
    int destroyed;
#else
    ap_dbd_t *rec;
#endif
};

typedef struct {
    dbd_cfg_t *cfg;
    dbd_group_t *group;
} svr_cfg;

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

static apr_pool_t *config_pool;
static dbd_group_t *group_list;

/* a default DBDriver value that'll generate meaningful error messages */
static const char *const no_dbdriver = "[DBDriver unset]";

/* 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 *create_dbd_config(apr_pool_t *pool, server_rec *s)
{
    svr_cfg *svr = apr_pcalloc(pool, sizeof(svr_cfg));
    dbd_cfg_t *cfg = svr->cfg = apr_pcalloc(pool, sizeof(dbd_cfg_t));

    cfg->server = s;
    cfg->name = no_dbdriver; /* to generate meaningful error messages */
    cfg->params = ""; /* don't risk segfault on misconfiguration */
    cfg->persist = -1;
#if APR_HAS_THREADS
    cfg->nmin = DEFAULT_NMIN;
    cfg->nkeep = DEFAULT_NKEEP;
    cfg->nmax = DEFAULT_NMAX;
    cfg->exptime = DEFAULT_EXPTIME;
#endif
    cfg->queries = apr_hash_make(pool);

    return svr;
}

static void *merge_dbd_config(apr_pool_t *pool, void *basev, void *addv)
{
    dbd_cfg_t *base = ((svr_cfg*) basev)->cfg;
    dbd_cfg_t *add = ((svr_cfg*) addv)->cfg;
    svr_cfg *svr = apr_pcalloc(pool, sizeof(svr_cfg));
    dbd_cfg_t *new = svr->cfg = apr_pcalloc(pool, sizeof(dbd_cfg_t));

    new->server = add->server;
    new->name = (add->name != no_dbdriver) ? add->name : base->name;
    new->params = strcmp(add->params, "") ? add->params : base->params;
    new->persist = (add->persist != -1) ? add->persist : base->persist;
#if APR_HAS_THREADS
    new->nmin = (add->set&NMIN_SET) ? add->nmin : base->nmin;
    new->nkeep = (add->set&NKEEP_SET) ? add->nkeep : base->nkeep;
    new->nmax = (add->set&NMAX_SET) ? add->nmax : base->nmax;
    new->exptime = (add->set&EXPTIME_SET) ? add->exptime : base->exptime;
#endif
    new->queries = apr_hash_overlay(pool, add->queries, base->queries);

    return svr;
}

#define ISINT(val) do {                                                 \
        const char *p;                                                  \
                                                                        \
        for (p = val; *p; ++p) {                                        \
            if (!apr_isdigit(*p)) {                                     \
                return "Argument must be numeric!";                     \
            }                                                           \
        }                                                               \
    } while (0)

static const char *dbd_param(cmd_parms *cmd, void *dconf, const char *val)
{
    const apr_dbd_driver_t *driver = NULL;
    svr_cfg *svr = ap_get_module_config(cmd->server->module_config,
                                        &dbd_module);
    dbd_cfg_t *cfg = svr->cfg;

    switch ((long) cmd->info) {
    case cmd_name:
        cfg->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, cfg->name, &driver)) {
        case APR_ENOTIMPL:
            return apr_psprintf(cmd->pool, "DBD: No driver for %s", cfg->name);
        case APR_EDSOOPEN:
            return apr_psprintf(cmd->pool,
#ifdef NETWARE
                                "DBD: Can't load driver file dbd%s.nlm",
#else
                                "DBD: Can't load driver file apr_dbd_%s.so",
#endif
                                cfg->name);
        case APR_ESYMNOTFOUND:
            return apr_psprintf(cmd->pool,
                                "DBD: Failed to load driver apr_dbd_%s_driver",
                                cfg->name);
        }
        break;
    case cmd_params:
        cfg->params = val;
        break;
#if APR_HAS_THREADS
    case cmd_min:
        ISINT(val);
        cfg->nmin = atoi(val);
        cfg->set |= NMIN_SET;
        break;
    case cmd_keep:
        ISINT(val);
        cfg->nkeep = atoi(val);
        cfg->set |= NKEEP_SET;
        break;
    case cmd_max:
        ISINT(val);
        cfg->nmax = atoi(val);
        cfg->set |= NMAX_SET;
        break;
    case cmd_exp:
        ISINT(val);
        cfg->exptime = atoi(val);
        cfg->set |= EXPTIME_SET;
        break;
#endif
    }

    return NULL;
}

static const char *dbd_param_flag(cmd_parms *cmd, void *dconf, int flag)
{
    svr_cfg *svr = ap_get_module_config(cmd->server->module_config,
                                        &dbd_module);

    switch ((long) cmd->info) {
    case cmd_persist:
        svr->cfg->persist = flag;
        break;
    }

    return NULL;
}

static const char *dbd_prepare(cmd_parms *cmd, void *dconf, const char *query,
                               const char *label)
{
    if (!label) {
        label = query;
        query = "";
    }

    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_TAKE12("DBDPrepareSQL", dbd_prepare, NULL, RSRC_CONF,
                   "SQL statement to prepare (or nothing, to override "
                   "statement inherited from main server) and 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 int dbd_pre_config(apr_pool_t *pconf, apr_pool_t *plog,
                          apr_pool_t *ptemp)
{
   config_pool = pconf;
   group_list = NULL;
   return OK;
}

DBD_DECLARE_NONSTD(void) ap_dbd_prepare(server_rec *s, const char *query,
                                        const char *label)
{
    svr_cfg *svr;

    svr = ap_get_module_config(s->module_config, &dbd_module);
    if (!svr) {
         /* some modules may call from within config directive handlers, and
          * if these are called in a server context that contains no mod_dbd
          * config directives, then we have to create our own server config
          */
         svr = create_dbd_config(config_pool, s);
         ap_set_module_config(s->module_config, &dbd_module, svr);
    }

    if (apr_hash_get(svr->cfg->queries, label, APR_HASH_KEY_STRING)
        && strcmp(query, "")) {
        ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s,
                     "conflicting SQL statements with label %s", label);
    }

    apr_hash_set(svr->cfg->queries, label, APR_HASH_KEY_STRING, query);
}

typedef struct {
    const char *label, *query;
} dbd_query_t;

static int dbd_post_config(apr_pool_t *pconf, apr_pool_t *plog,
                           apr_pool_t *ptemp, server_rec *s)
{
    server_rec *sp;
    apr_array_header_t *add_queries = apr_array_make(ptemp, 10,
                                                     sizeof(dbd_query_t));

    for (sp = s; sp; sp = sp->next) {
        svr_cfg *svr = ap_get_module_config(sp->module_config, &dbd_module);
        dbd_cfg_t *cfg = svr->cfg;
        apr_hash_index_t *hi_first = apr_hash_first(ptemp, cfg->queries);
        dbd_group_t *group;

        /* dbd_setup in 2.2.3 and under was causing spurious error messages
         * when dbd isn't configured.  We can stop that with a quick check here
         * together with a similar check in ap_dbd_open (where being
         * unconfigured is a genuine error that must be reported).
         */
        if (cfg->name == no_dbdriver || !cfg->persist) {
            continue;
        }

        for (group = group_list; group; group = group->next) {
            dbd_cfg_t *group_cfg = group->cfg;
            apr_hash_index_t *hi;
            int group_ok = 1;

            if (strcmp(cfg->name, group_cfg->name)
                || strcmp(cfg->params, group_cfg->params)) {
                continue;
            }

#if APR_HAS_THREADS
            if (cfg->nmin != group_cfg->nmin
                || cfg->nkeep != group_cfg->nkeep
                || cfg->nmax != group_cfg->nmax
                || cfg->exptime != group_cfg->exptime) {
                continue;
            }
#endif

            add_queries->nelts = 0;

            for (hi = hi_first; hi; hi = apr_hash_next(hi)) {
                const char *label, *query;
                const char *group_query;

                apr_hash_this(hi, (void*) &label, NULL, (void*) &query);

                group_query = apr_hash_get(group_cfg->queries, label,
                                           APR_HASH_KEY_STRING);

                if (!group_query) {
                    dbd_query_t *add_query = apr_array_push(add_queries);

                    add_query->label = label;
                    add_query->query = query;
                }
                else if (strcmp(query, group_query)) {
                    group_ok = 0;
                    break;
                }
            }

            if (group_ok) {
                int i;

                for (i = 0; i < add_queries->nelts; ++i) {
                    dbd_query_t *add_query = ((dbd_query_t*) add_queries->elts)
                                             + i;

                    apr_hash_set(group_cfg->queries, add_query->label,
                                 APR_HASH_KEY_STRING, add_query->query);
                }

                svr->group = group;
                break;
            }
        }

        if (!svr->group) {
            svr->group = group = apr_pcalloc(pconf, sizeof(dbd_group_t));

            group->cfg = cfg;

            group->next = group_list;
            group_list = group;
        }
    }

    return OK;
}

static apr_status_t dbd_prepared_init(apr_pool_t *pool, dbd_cfg_t *cfg,
                                      ap_dbd_t *rec)
{
    apr_hash_index_t *hi;
    apr_status_t rv = APR_SUCCESS;

    rec->prepared = apr_hash_make(pool);

    for (hi = apr_hash_first(pool, cfg->queries); hi;
         hi = apr_hash_next(hi)) {
        const char *label, *query;
        apr_dbd_prepared_t *stmt;

        apr_hash_this(hi, (void*) &label, NULL, (void*) &query);

        if (!strcmp(query, "")) {
            continue;
        }

        stmt = NULL;
        if (apr_dbd_prepare(rec->driver, pool, rec->handle, query,
                            label, &stmt)) {
            rv = APR_EGENERAL;
        }
        else {
            apr_hash_set(rec->prepared, label, APR_HASH_KEY_STRING, stmt);
        }
    }

    return rv;
}

static apr_status_t dbd_close(void *data)
{
    ap_dbd_t *rec = data;

    return apr_dbd_close(rec->driver, rec->handle);
}

#if APR_HAS_THREADS
static apr_status_t dbd_destruct(void *data, void *params, apr_pool_t *pool)
{
    dbd_group_t *group = params;

    if (!group->destroyed) {
        ap_dbd_t *rec = data;

        apr_pool_destroy(rec->pool);
    }

    return APR_SUCCESS;
}
#endif

/* 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 **data_ptr,
                                  void *params, apr_pool_t *pool)
{
    dbd_group_t *group = params;
    dbd_cfg_t *cfg = group->cfg;
    apr_pool_t *rec_pool, *prepared_pool;
    ap_dbd_t *rec;