root/ext/session/mod_mm.c

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DEFINITIONS

This source file includes following definitions.
  1. ps_sd_hash
  2. hash_split
  3. ps_sd_new
  4. ps_sd_destroy
  5. ps_sd_lookup
  6. ps_mm_initialize
  7. ps_mm_destroy
  8. PHP_MINIT_FUNCTION
  9. PHP_MSHUTDOWN_FUNCTION
  10. PS_OPEN_FUNC
  11. PS_CLOSE_FUNC
  12. PS_READ_FUNC
  13. PS_WRITE_FUNC
  14. PS_DESTROY_FUNC
  15. 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.               |
   +----------------------------------------------------------------------+
   | Author: Sascha Schumann <sascha@schumann.cx>                         |
   +----------------------------------------------------------------------+
 */

/* $Id: mod_mm.c,v 1.46.2.1.2.6 2007/12/31 07:20:10 sebastian Exp $ */

#include "php.h"

#ifdef HAVE_LIBMM

#include <unistd.h>
#include <mm.h>
#include <time.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <fcntl.h>

#include "php_session.h"
#include "mod_mm.h"
#include "SAPI.h"

#ifdef ZTS
# error mm is not thread-safe
#endif

#define PS_MM_FILE "session_mm_"

/* For php_uint32 */
#include "ext/standard/basic_functions.h"

/*
 * this list holds all data associated with one session 
 */

typedef struct ps_sd {
        struct ps_sd *next;
        php_uint32 hv;          /* hash value of key */
        time_t ctime;           /* time of last change */
        void *data;
        size_t datalen;         /* amount of valid data */
        size_t alloclen;        /* amount of allocated memory for data */
        char key[1];            /* inline key */
} ps_sd;

typedef struct {
        MM *mm;
        ps_sd **hash;
        php_uint32 hash_max;
        php_uint32 hash_cnt;
        pid_t owner;
} ps_mm;

static ps_mm *ps_mm_instance = NULL;

#if 0
#define ps_mm_debug(a) printf a
#else
#define ps_mm_debug(a)
#endif

static inline php_uint32 ps_sd_hash(const char *data, int len)
{
        php_uint32 h;
        const char *e = data + len;
        
        for (h = 2166136261U; data < e; ) {
                h *= 16777619;
                h ^= *data++;
        }
        
        return h;
}

static void hash_split(ps_mm *data)
{
        php_uint32 nmax;
        ps_sd **nhash;
        ps_sd **ohash, **ehash;
        ps_sd *ps, *next;
        
        nmax = ((data->hash_max + 1) << 1) - 1;
        nhash = mm_calloc(data->mm, nmax + 1, sizeof(*data->hash));
        
        if (!nhash) {
                /* no further memory to expand hash table */
                return;
        }

        ehash = data->hash + data->hash_max + 1;
        for (ohash = data->hash; ohash < ehash; ohash++) {
                for (ps = *ohash; ps; ps = next) {
                        next = ps->next;
                        ps->next = nhash[ps->hv & nmax];
                        nhash[ps->hv & nmax] = ps;
                }
        }
        mm_free(data->mm, data->hash);

        data->hash = nhash;
        data->hash_max = nmax;
}

static ps_sd *ps_sd_new(ps_mm *data, const char *key)
{
        php_uint32 hv, slot;
        ps_sd *sd;
        int keylen;
        
        keylen = strlen(key);
        
        sd = mm_malloc(data->mm, sizeof(ps_sd) + keylen);
        if (!sd) {
                TSRMLS_FETCH();

                php_error_docref(NULL TSRMLS_CC, E_WARNING, "mm_malloc failed, avail %d, err %s", mm_available(data->mm), mm_error());
                return NULL;
        }

        hv = ps_sd_hash(key, keylen);
        slot = hv & data->hash_max;
        
        sd->ctime = 0;
        sd->hv = hv;
        sd->data = NULL;
        sd->alloclen = sd->datalen = 0;
        
        memcpy(sd->key, key, keylen + 1);
        
        sd->next = data->hash[slot];
        data->hash[slot] = sd;

        data->hash_cnt++;
        
        if (!sd->next) {
                if (data->hash_cnt >= data->hash_max)
                        hash_split(data);
        }
        
        ps_mm_debug(("inserting %s(%p) into slot %d\n", key, sd, slot));

        return sd;
}

static void ps_sd_destroy(ps_mm *data, ps_sd *sd)
{
        php_uint32 slot;

        slot = ps_sd_hash(sd->key, strlen(sd->key)) & data->hash_max;

        if (data->hash[slot] == sd)
                data->hash[slot] = sd->next;
        else {
                ps_sd *prev;

                /* There must be some entry before the one we want to delete */
                for (prev = data->hash[slot]; prev->next != sd; prev = prev->next);
                prev->next = sd->next;
        }
                
        data->hash_cnt--;
        if (sd->data) 
                mm_free(data->mm, sd->data);
        mm_free(data->mm, sd);
}

static ps_sd *ps_sd_lookup(ps_mm *data, const char *key, int rw)
{
        php_uint32 hv, slot;
        ps_sd *ret, *prev;

        hv = ps_sd_hash(key, strlen(key));
        slot = hv & data->hash_max;
        
        for (prev = NULL, ret = data->hash[slot]; ret; prev = ret, ret = ret->next)
                if (ret->hv == hv && !strcmp(ret->key, key)) 
                        break;
        
        if (ret && rw && ret != data->hash[slot]) {
                /* Move the entry to the top of the linked list */
                
                if (prev)
                        prev->next = ret->next;
                ret->next = data->hash[slot];
                data->hash[slot] = ret;
        }

        ps_mm_debug(("lookup(%s): ret=%p,hv=%u,slot=%d\n", key, ret, hv, slot));
        
        return ret;
}

ps_module ps_mod_mm = {
        PS_MOD(mm)
};

#define PS_MM_DATA ps_mm *data = PS_GET_MOD_DATA()

static int ps_mm_initialize(ps_mm *data, const char *path)
{
        data->owner = getpid();
        data->mm = mm_create(0, path);
        if (!data->mm) {
                return FAILURE;
        }

        data->hash_cnt = 0;
        data->hash_max = 511;
        data->hash = mm_calloc(data->mm, data->hash_max + 1, sizeof(ps_sd *));
        if (!data->hash) {
                mm_destroy(data->mm);
                return FAILURE;
        }

        return SUCCESS;
}

static void ps_mm_destroy(ps_mm *data)
{
        int h;
        ps_sd *sd, *next;

        /* This function is called during each module shutdown,
           but we must not release the shared memory pool, when
           an Apache child dies! */
        if (data->owner != getpid()) return;

        for (h = 0; h < data->hash_max + 1; h++)
                for (sd = data->hash[h]; sd; sd = next) {
                        next = sd->next;
                        ps_sd_destroy(data, sd);
                }
        
        mm_free(data->mm, data->hash);
        mm_destroy(data->mm);
        free(data);
}

PHP_MINIT_FUNCTION(ps_mm)
{
        int save_path_len = strlen(PS(save_path));
        int mod_name_len = strlen(sapi_module.name);
        int euid_len;
        char *ps_mm_path, euid[30];
        int ret;

        ps_mm_instance = calloc(sizeof(*ps_mm_instance), 1);
        if (!ps_mm_instance) {
                return FAILURE;
        }

        if (!(euid_len = slprintf(euid, sizeof(euid), "%d", geteuid()))) {
                return FAILURE;
        }
                
        /* Directory + '/' + File + Module Name + Effective UID + \0 */ 
        ps_mm_path = emalloc(save_path_len + 1 + (sizeof(PS_MM_FILE) - 1) + mod_name_len + euid_len + 1);
        
        memcpy(ps_mm_path, PS(save_path), save_path_len);
        if (PS(save_path)[save_path_len - 1] != DEFAULT_SLASH) {
                ps_mm_path[save_path_len] = DEFAULT_SLASH;
                save_path_len++;
        }
        memcpy(ps_mm_path + save_path_len, PS_MM_FILE, sizeof(PS_MM_FILE) - 1);
        save_path_len += sizeof(PS_MM_FILE) - 1;
        memcpy(ps_mm_path + save_path_len, sapi_module.name, mod_name_len);
        save_path_len += mod_name_len;
        memcpy(ps_mm_path + save_path_len, euid, euid_len);
        ps_mm_path[save_path_len + euid_len] = '\0';

        ret = ps_mm_initialize(ps_mm_instance, ps_mm_path);
                
        efree(ps_mm_path);
   
        if (ret != SUCCESS) {
                free(ps_mm_instance);
                ps_mm_instance = NULL;
                return FAILURE;
        }
        
        php_session_register_module(&ps_mod_mm);
        return SUCCESS;
}

PHP_MSHUTDOWN_FUNCTION(ps_mm)
{
        if (ps_mm_instance) {
                ps_mm_destroy(ps_mm_instance);
                return SUCCESS;
        }
        return FAILURE;
}

PS_OPEN_FUNC(mm)
{
        ps_mm_debug(("open: ps_mm_instance=%p\n", ps_mm_instance));
        
        if (!ps_mm_instance)
                return FAILURE;
        
        PS_SET_MOD_DATA(ps_mm_instance);
        
        return SUCCESS;
}

PS_CLOSE_FUNC(mm)
{
        PS_SET_MOD_DATA(NULL);

        return SUCCESS;
}

PS_READ_FUNC(mm)
{
        PS_MM_DATA;
        ps_sd *sd;
        int ret = FAILURE;

        mm_lock(data->mm, MM_LOCK_RD);
        
        sd = ps_sd_lookup(data, key, 0);
        if (sd) {
                *vallen = sd->datalen;
                *val = emalloc(sd->datalen + 1);
                memcpy(*val, sd->data, sd->datalen);
                (*val)[sd->datalen] = '\0';
                ret = SUCCESS;
        }

        mm_unlock(data->mm);
        
        return ret;
}

PS_WRITE_FUNC(mm)
{
        PS_MM_DATA;
        ps_sd *sd;

        mm_lock(data->mm, MM_LOCK_RW);

        sd = ps_sd_lookup(data, key, 1);
        if (!sd) {
                sd = ps_sd_new(data, key);
                ps_mm_debug(("new entry for %s\n", key));
        }

        if (sd) {
                if (vallen >= sd->alloclen) {
                        if (data->mm) 
                                mm_free(data->mm, sd->data);
                        sd->alloclen = vallen + 1;
                        sd->data = mm_malloc(data->mm, sd->alloclen);

                        if (!sd->data) {
                                ps_sd_destroy(data, sd);
                                php_error_docref(NULL TSRMLS_CC, E_WARNING, "cannot allocate new data segment");
                                sd = NULL;
                        }
                }
                if (sd) {
                        sd->datalen = vallen;
                        memcpy(sd->data, val, vallen);
                        time(&sd->ctime);
                }
        }

        mm_unlock(data->mm);
        
        return sd ? SUCCESS : FAILURE;
}

PS_DESTROY_FUNC(mm)
{
        PS_MM_DATA;
        ps_sd *sd;
        
        mm_lock(data->mm, MM_LOCK_RW);
        
        sd = ps_sd_lookup(data, key, 0);
        if (sd)
                ps_sd_destroy(data, sd);
        
        mm_unlock(data->mm);
        
        return SUCCESS;
}

PS_GC_FUNC(mm) 
{
        PS_MM_DATA;
        time_t limit;
        ps_sd **ohash, **ehash;
        ps_sd *sd, *next;
        
        *nrdels = 0;
        ps_mm_debug(("gc\n"));
                
        time(&limit);

        limit -= maxlifetime;

        mm_lock(data->mm, MM_LOCK_RW);

        ehash = data->hash + data->hash_max + 1;
        for (ohash = data->hash; ohash < ehash; ohash++)
                for (sd = *ohash; sd; sd = next) {
                        next = sd->next;
                        if (sd->ctime < limit) {
                                ps_mm_debug(("purging %s\n", sd->key));
                                ps_sd_destroy(data, sd);
                                (*nrdels)++;
                        }
                }

        mm_unlock(data->mm);
        
        return SUCCESS;
}

#endif

/*
 * Local variables:
 * tab-width: 4
 * c-basic-offset: 4
 * End:
 * vim600: sw=4 ts=4 fdm=marker
 * vim<600: sw=4 ts=4
 */

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