root/ext/sqlite/sess_sqlite.c

DEFINITIONS

1. PS_OPEN_FUNC
2. PS_CLOSE_FUNC
3. PS_READ_FUNC
4. PS_WRITE_FUNC
5. PS_DESTROY_FUNC
6. PS_GC_FUNC

/* 
   +----------------------------------------------------------------------+
   | PHP Version 5                                                        |
   +----------------------------------------------------------------------+
   | Copyright (c) 1997-2008 The PHP Group                                |
   +----------------------------------------------------------------------+
   | This source file is subject to version 3.01 of the PHP license,      |
   | that is bundled with this package in the file LICENSE, and is        |
   | available through the world-wide-web at the following url:           |
   | http://www.php.net/license/3_01.txt                                  |
   | If you did not receive a copy of the PHP license and are unable to   |
   | obtain it through the world-wide-web, please send a note to          |
   | license@php.net so we can mail you a copy immediately.               |
   +----------------------------------------------------------------------+
   | Authors: John Coggeshall <john@php.net>                              |
   |          Wez Furlong <wez@thebrainroom.com>                          |
   +----------------------------------------------------------------------+
 */

/* $Id: sess_sqlite.c,v 1.18.2.1.2.3 2007/12/31 07:20:11 sebastian Exp $ */

#include "php.h"

#if HAVE_PHP_SESSION && !defined(COMPILE_DL_SESSION)

#include "ext/session/php_session.h"
#include "ext/standard/php_lcg.h"
#include <sqlite.h>
#define SQLITE_RETVAL(__r) ((__r) == SQLITE_OK ? SUCCESS : FAILURE)
#define PS_SQLITE_DATA sqlite *db = (sqlite*)PS_GET_MOD_DATA()
extern int sqlite_encode_binary(const unsigned char *in, int n, unsigned char *out);
extern int sqlite_decode_binary(const unsigned char *in, unsigned char *out);

PS_FUNCS(sqlite);

ps_module ps_mod_sqlite = {
        PS_MOD(sqlite)
};

PS_OPEN_FUNC(sqlite) 
{
        char *errmsg = NULL;
        sqlite *db;

        /* TODO: do we need a safe_mode check here? */
        db = sqlite_open(save_path, 0666, &errmsg);
        if (db == NULL) {
                php_error_docref(NULL TSRMLS_CC, E_WARNING, 
                                "SQLite: failed to open/create session database `%s' - %s", save_path, errmsg);
                sqlite_freemem(errmsg);
                return FAILURE;
        }

        /* allow up to 1 minute when busy */
        sqlite_busy_timeout(db, 60000);

        sqlite_exec(db, "PRAGMA default_synchronous = OFF", NULL, NULL, NULL);
        sqlite_exec(db, "PRAGMA count_changes = OFF", NULL, NULL, NULL);

        /* This will fail if the table already exists, but that's not a big problem. I'm
           unclear as to how to check for a table's existence in SQLite -- that would be better here. */
        sqlite_exec(db, 
            "CREATE TABLE session_data ("
            "    sess_id PRIMARY KEY," 
            "    value TEXT, "
            "    updated INTEGER "
            ")", NULL, NULL, NULL);

        PS_SET_MOD_DATA(db);

        return SUCCESS;
}

PS_CLOSE_FUNC(sqlite) 
{
        PS_SQLITE_DATA;

        sqlite_close(db);

        return SUCCESS;
}

PS_READ_FUNC(sqlite) 
{
        PS_SQLITE_DATA;
        char *query;
        const char *tail;
        sqlite_vm *vm;
        int colcount, result;
        const char **rowdata, **colnames;
        char *error;

        *val = NULL;
        *vallen = 0;
        
        query = sqlite_mprintf("SELECT value FROM session_data WHERE sess_id='%q' LIMIT 1", key);
        if (query == NULL) {
                /* no memory */
                return FAILURE;
        }

        if (sqlite_compile(db, query, &tail, &vm, &error) != SQLITE_OK) {
                php_error_docref(NULL TSRMLS_CC, E_WARNING, "SQLite: Could not compile session read query: %s", error);
                sqlite_freemem(error);
                sqlite_freemem(query);
                return FAILURE;
        }

        switch ((result = sqlite_step(vm, &colcount, &rowdata, &colnames))) {
                case SQLITE_ROW:
                        if (rowdata[0] != NULL) {
                                *vallen = strlen(rowdata[0]);
                                if (*vallen) {
                                        *val = emalloc(*vallen);
                                        *vallen = sqlite_decode_binary(rowdata[0], *val);
                                        (*val)[*vallen] = '\0';
                                } else {
                                        *val = STR_EMPTY_ALLOC();
                                }
                        }
                        break;
                default:
                        sqlite_freemem(error);
                        error = NULL;
        }
        
        if (SQLITE_OK != sqlite_finalize(vm, &error)) {
                php_error_docref(NULL TSRMLS_CC, E_WARNING, "SQLite: session read: error %s", error);
                sqlite_freemem(error);
                error = NULL;
        }

        sqlite_freemem(query);
        
        return *val == NULL ? FAILURE : SUCCESS;
}

PS_WRITE_FUNC(sqlite) 
{
        PS_SQLITE_DATA;
        char *error;
        time_t t;
        char *binary;
        int binlen;
        int rv;
        
        t = time(NULL);

        binary = safe_emalloc(1 + vallen / 254, 257, 3);
        binlen = sqlite_encode_binary((const unsigned char*)val, vallen, binary);
        
        rv = sqlite_exec_printf(db, "REPLACE INTO session_data VALUES('%q', '%q', %d)", NULL, NULL, &error, key, binary, t);
        if (rv != SQLITE_OK) {
                php_error_docref(NULL TSRMLS_CC, E_WARNING, "SQLite: session write query failed: %s", error);
                sqlite_freemem(error);
        }
        efree(binary);

        return SQLITE_RETVAL(rv);
}

PS_DESTROY_FUNC(sqlite) 
{
        int rv;
        PS_SQLITE_DATA;

        rv = sqlite_exec_printf(db, "DELETE FROM session_data WHERE sess_id='%q'", NULL, NULL, NULL, key);
        
        return SQLITE_RETVAL(rv);
}

PS_GC_FUNC(sqlite) 
{
        PS_SQLITE_DATA;
        int rv;
        time_t t = time(NULL);

        rv = sqlite_exec_printf(db, 
                        "DELETE FROM session_data WHERE (%d - updated) > %d", 
                        NULL, NULL, NULL, t, maxlifetime);

        /* because SQLite does not actually clear the deleted data from the database 
         * we need to occassionaly do so manually to prevent the sessions database 
         * from growing endlessly.
         */
        if ((int) ((float) PS(gc_divisor) * PS(gc_divisor) * php_combined_lcg(TSRMLS_C)) < PS(gc_probability)) {
                rv = sqlite_exec_printf(db, "VACUUM", NULL, NULL, NULL);
        }
        return SQLITE_RETVAL(rv);
}

#endif /* HAVE_PHP_SESSION && !defined(COMPILE_DL_SESSION) */

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