mod_rewrite.c

Apache官方在今天放出产品系列2.2的最新版本2.2.11的源码包 最流行的HTTP服务器软件之一

    }

    return 0;
}

/*
 * substitute the prefix path 'match' in 'input' with 'subst' (RewriteBase)
 */
static char *subst_prefix_path(request_rec *r, char *input, char *match,
                               const char *subst)
{
    apr_size_t len = strlen(match);

    if (len && match[len - 1] == '/') {
        --len;
    }

    if (!strncmp(input, match, len) && input[len++] == '/') {
        apr_size_t slen, outlen;
        char *output;

        rewritelog((r, 5, NULL, "strip matching prefix: %s -> %s", input,
                    input+len));

        slen = strlen(subst);
        if (slen && subst[slen - 1] != '/') {
            ++slen;
        }

        outlen = strlen(input) + slen - len;
        output = apr_palloc(r->pool, outlen + 1); /* don't forget the \0 */

        memcpy(output, subst, slen);
        if (slen && !output[slen-1]) {
            output[slen-1] = '/';
        }
        memcpy(output+slen, input+len, outlen - slen);
        output[outlen] = '\0';

        rewritelog((r, 4, NULL, "add subst prefix: %s -> %s", input+len,
                    output));

        return output;
    }

    /* prefix didn't match */
    return input;
}


/*
 * +-------------------------------------------------------+
 * |                                                       |
 * |                    caching support
 * |                                                       |
 * +-------------------------------------------------------+
 */

static void set_cache_value(const char *name, apr_time_t t, char *key,
                            char *val)
{
    cachedmap *map;

    if (cachep) {
#if APR_HAS_THREADS
        apr_thread_mutex_lock(cachep->lock);
#endif
        map = apr_hash_get(cachep->maps, name, APR_HASH_KEY_STRING);

        if (!map) {
            apr_pool_t *p;

            if (apr_pool_create(&p, cachep->pool) != APR_SUCCESS) {
#if APR_HAS_THREADS
                apr_thread_mutex_unlock(cachep->lock);
#endif
                return;
            }

            map = apr_palloc(cachep->pool, sizeof(cachedmap));
            map->pool = p;
            map->entries = apr_hash_make(map->pool);
            map->mtime = t;

            apr_hash_set(cachep->maps, name, APR_HASH_KEY_STRING, map);
        }
        else if (map->mtime != t) {
            apr_pool_clear(map->pool);
            map->entries = apr_hash_make(map->pool);
            map->mtime = t;
        }

        /* Now we should have a valid map->entries hash, where we
         * can store our value.
         *
         * We need to copy the key and the value into OUR pool,
         * so that we don't leave it during the r->pool cleanup.
         */
        apr_hash_set(map->entries,
                     apr_pstrdup(map->pool, key), APR_HASH_KEY_STRING,
                     apr_pstrdup(map->pool, val));

#if APR_HAS_THREADS
        apr_thread_mutex_unlock(cachep->lock);
#endif
    }

    return;
}

static char *get_cache_value(const char *name, apr_time_t t, char *key,
                             apr_pool_t *p)
{
    cachedmap *map;
    char *val = NULL;

    if (cachep) {
#if APR_HAS_THREADS
        apr_thread_mutex_lock(cachep->lock);
#endif
        map = apr_hash_get(cachep->maps, name, APR_HASH_KEY_STRING);

        if (map) {
            /* if this map is outdated, forget it. */
            if (map->mtime != t) {
                apr_pool_clear(map->pool);
                map->entries = apr_hash_make(map->pool);
                map->mtime = t;
            }
            else {
                val = apr_hash_get(map->entries, key, APR_HASH_KEY_STRING);
                if (val) {
                    /* copy the cached value into the supplied pool,
                     * where it belongs (r->pool usually)
                     */
                    val = apr_pstrdup(p, val);
                }
            }
        }

#if APR_HAS_THREADS
        apr_thread_mutex_unlock(cachep->lock);
#endif
    }

    return val;
}

static int init_cache(apr_pool_t *p)
{
    cachep = apr_palloc(p, sizeof(cache));
    if (apr_pool_create(&cachep->pool, p) != APR_SUCCESS) {
        cachep = NULL; /* turns off cache */
        return 0;
    }

    cachep->maps = apr_hash_make(cachep->pool);
#if APR_HAS_THREADS
    (void)apr_thread_mutex_create(&(cachep->lock), APR_THREAD_MUTEX_DEFAULT, p);
#endif

    return 1;
}


/*
 * +-------------------------------------------------------+
 * |                                                       |
 * |                    Map Functions
 * |                                                       |
 * +-------------------------------------------------------+
 */

/*
 * General Note: key is already a fresh string, created (expanded) just
 * for the purpose to be passed in here. So one can modify key itself.
 */

static char *rewrite_mapfunc_toupper(request_rec *r, char *key)
{
    char *p;

    for (p = key; *p; ++p) {
        *p = apr_toupper(*p);
    }

    return key;
}

static char *rewrite_mapfunc_tolower(request_rec *r, char *key)
{
    ap_str_tolower(key);

    return key;
}

static char *rewrite_mapfunc_escape(request_rec *r, char *key)
{
    return ap_escape_uri(r->pool, key);
}

static char *rewrite_mapfunc_unescape(request_rec *r, char *key)
{
    ap_unescape_url(key);

    return key;
}

static char *select_random_value_part(request_rec *r, char *value)
{
    char *p = value;
    unsigned n = 1;

    /* count number of distinct values */
    while ((p = ap_strchr(p, '|')) != NULL) {
        ++n;
        ++p;
    }

    if (n > 1) {
        /* initialize random generator
         *
         * XXX: Probably this should be wrapped into a thread mutex,
         * shouldn't it? Is it worth the effort?
         */
        if (!rewrite_rand_init_done) {
            srand((unsigned)(getpid()));
            rewrite_rand_init_done = 1;
        }

        /* select a random subvalue */
        n = (int)(((double)(rand() % RAND_MAX) / RAND_MAX) * n + 1);

        /* extract it from the whole string */
        while (--n && (value = ap_strchr(value, '|')) != NULL) {
            ++value;
        }

        if (value) { /* should not be NULL, but ... */
            p = ap_strchr(value, '|');
            if (p) {
                *p = '\0';
            }
        }
    }

    return value;
}

/* child process code */
static void rewrite_child_errfn(apr_pool_t *p, apr_status_t err,
                                const char *desc)
{
    ap_log_error(APLOG_MARK, APLOG_ERR, err, NULL, "%s", desc);
}

static apr_status_t rewritemap_program_child(apr_pool_t *p,
                                             const char *progname, char **argv,
                                             apr_file_t **fpout,
                                             apr_file_t **fpin)
{
    apr_status_t rc;
    apr_procattr_t *procattr;
    apr_proc_t *procnew;

    if (   APR_SUCCESS == (rc=apr_procattr_create(&procattr, p))
        && APR_SUCCESS == (rc=apr_procattr_io_set(procattr, APR_FULL_BLOCK,
                                                  APR_FULL_BLOCK, APR_NO_PIPE))
        && APR_SUCCESS == (rc=apr_procattr_dir_set(procattr,
                                             ap_make_dirstr_parent(p, argv[0])))
        && APR_SUCCESS == (rc=apr_procattr_cmdtype_set(procattr, APR_PROGRAM))
        && APR_SUCCESS == (rc=apr_procattr_child_errfn_set(procattr,
                                                           rewrite_child_errfn))
        && APR_SUCCESS == (rc=apr_procattr_error_check_set(procattr, 1))) {

        procnew = apr_pcalloc(p, sizeof(*procnew));
        rc = apr_proc_create(procnew, argv[0], (const char **)argv, NULL,
                             procattr, p);

        if (rc == APR_SUCCESS) {
            apr_pool_note_subprocess(p, procnew, APR_KILL_AFTER_TIMEOUT);

            if (fpin) {
                (*fpin) = procnew->in;
            }

            if (fpout) {
                (*fpout) = procnew->out;
            }
        }
    }

    return (rc);
}

static apr_status_t run_rewritemap_programs(server_rec *s, apr_pool_t *p)
{
    rewrite_server_conf *conf;
    apr_hash_index_t *hi;
    apr_status_t rc;
    int lock_warning_issued = 0;

    conf = ap_get_module_config(s->module_config, &rewrite_module);

    /*  If the engine isn't turned on,
     *  don't even try to do anything.
     */
    if (conf->state == ENGINE_DISABLED) {
        return APR_SUCCESS;
    }

    for (hi = apr_hash_first(p, conf->rewritemaps); hi; hi = apr_hash_next(hi)){
        apr_file_t *fpin = NULL;
        apr_file_t *fpout = NULL;
        rewritemap_entry *map;
        void *val;

        apr_hash_this(hi, NULL, NULL, &val);
        map = val;

        if (map->type != MAPTYPE_PRG) {
            continue;
        }
        if (!(map->argv[0]) || !*(map->argv[0]) || map->fpin || map->fpout) {
            continue;
        }

        if (!lock_warning_issued && (!lockname || !*lockname)) {
            ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s,
                         "mod_rewrite: Running external rewrite maps "
                         "without defining a RewriteLock is DANGEROUS!");
            ++lock_warning_issued;
        }

        rc = rewritemap_program_child(p, map->argv[0], map->argv,
                                      &fpout, &fpin);
        if (rc != APR_SUCCESS || fpin == NULL || fpout == NULL) {
            ap_log_error(APLOG_MARK, APLOG_ERR, rc, s,
                         "mod_rewrite: could not start RewriteMap "
                         "program %s", map->checkfile);
            return rc;
        }
        map->fpin  = fpin;
        map->fpout = fpout;
    }

    return APR_SUCCESS;
}


/*
 * +-------------------------------------------------------+
 * |                                                       |
 * |                  Lookup functions
 * |                                                       |
 * +-------------------------------------------------------+
 */

static char *lookup_map_txtfile(request_rec *r, const char *file, char *key)
{
    apr_file_t *fp = NULL;
    char line[REWRITE_MAX_TXT_MAP_LINE + 1]; /* +1 for \0 */
    char *value, *keylast;

    if (apr_file_open(&fp, file, APR_READ|APR_BUFFERED, APR_OS_DEFAULT,
                      r->pool) != APR_SUCCESS) {
        return NULL;
    }

    keylast = key + strlen(key);
    value = NULL;
    while (apr_file_gets(line, sizeof(line), fp) == APR_SUCCESS) {
        char *p, *c;

        /* ignore comments and lines starting with whitespaces */
        if (*line == '#' || apr_isspace(*line)) {
            continue;
        }

        p = line;
        c = key;
        while (c < keylast && *p == *c && !apr_isspace(*p)) {
            ++p;
            ++c;
        }

        /* key doesn't match - ignore. */
        if (c != keylast || !apr_isspace(*p)) {
            continue;
        }

        /* jump to the value */
        while (*p && apr_isspace(*p)) {
            ++p;
        }

        /* no value? ignore */
        if (!*p) {
            continue;
        }

        /* extract the value and return. */
        c = p;
        while (*p && !apr_isspace(*p)) {
            ++p;
        }
        value = apr_pstrmemdup(r->pool, c, p - c);
        break;
    }
    apr_file_close(fp);

    return value;
}

static char *lookup_map_dbmfile(request_rec *r, const char *file,
                                const char *dbmtype, char *key)
{
    apr_dbm_t *dbmfp = NULL;
    apr_datum_t dbmkey;
    apr_datum_t dbmval;
    char *value;

    if (apr_dbm_open_ex(&dbmfp, dbmtype, file, APR_DBM_READONLY, APR_OS_DEFAULT,
                        r->pool) != APR_SUCCESS) {
        return NULL;
    }

    dbmkey.dptr  = key;
    dbmkey.dsize = strlen(key);

    if (apr_dbm_fetch(dbmfp, dbmkey, &dbmval) == APR_SUCCESS && dbmval.dptr) {
        value = apr_pstrmemdup(r->pool, dbmval.dptr, dbmval.dsize);
    }
    else {
        value = NULL;
    }

    apr_dbm_close(dbmfp);