mod_log_config.c

Apache HTTP Server 是一个功能强大的灵活的与HTTP/1.1相兼容的web服务器.这里给出的是Apache HTTP服务器的源码。

            it->arg = ap_getword(p, &s, '}');
            break;

        case '0':
        case '1':
        case '2':
        case '3':
        case '4':
        case '5':
        case '6':
        case '7':
        case '8':
        case '9':
            i = *s - '0';
            while (apr_isdigit(*++s)) {
                i = i * 10 + (*s) - '0';
            }
            if (!it->conditions) {
                it->conditions = apr_array_make(p, 4, sizeof(int));
            }
            *(int *) apr_array_push(it->conditions) = i;
            break;

        default:
            handler = (ap_log_handler *)apr_hash_get(log_hash, s++, 1);
            if (!handler) {
                char dummy[2];

                dummy[0] = s[-1];
                dummy[1] = '\0';
                return apr_pstrcat(p, "Unrecognized LogFormat directive %",
                               dummy, NULL);
            }
            it->func = handler->func;
            if (it->want_orig == -1) {
                it->want_orig = handler->want_orig_default;
            }
            *sa = s;
            return NULL;
        }
    }

    return "Ran off end of LogFormat parsing args to some directive";
}

static apr_array_header_t *parse_log_string(apr_pool_t *p, const char *s, const char **err)
{
    apr_array_header_t *a = apr_array_make(p, 30, sizeof(log_format_item));
    char *res;

    while (*s) {
        if ((res = parse_log_item(p, (log_format_item *) apr_array_push(a), &s))) {
            *err = res;
            return NULL;
        }
    }

    s = APR_EOL_STR;
    parse_log_item(p, (log_format_item *) apr_array_push(a), &s);
    return a;
}

/*****************************************************************
 *
 * Actually logging.
 */

static const char *process_item(request_rec *r, request_rec *orig,
                          log_format_item *item)
{
    const char *cp;

    /* First, see if we need to process this thing at all... */

    if (item->conditions && item->conditions->nelts != 0) {
        int i;
        int *conds = (int *) item->conditions->elts;
        int in_list = 0;

        for (i = 0; i < item->conditions->nelts; ++i) {
            if (r->status == conds[i]) {
                in_list = 1;
                break;
            }
        }

        if ((item->condition_sense && in_list)
            || (!item->condition_sense && !in_list)) {
            return "-";
        }
    }

    /* We do.  Do it... */

    cp = (*item->func) (item->want_orig ? orig : r, item->arg);
    return cp ? cp : "-";
}

static void flush_log(buffered_log *buf)
{
    if (buf->outcnt && buf->handle != NULL) {
        apr_file_write(buf->handle, buf->outbuf, &buf->outcnt);
        buf->outcnt = 0;
    }
}


static int config_log_transaction(request_rec *r, config_log_state *cls,
                                  apr_array_header_t *default_format)
{
    log_format_item *items;
    const char **strs;
    int *strl;
    request_rec *orig;
    int i;
    apr_size_t len = 0;
    apr_array_header_t *format;
    char *envar;
    apr_status_t rv;

    if (cls->fname == NULL) {
        return DECLINED;
    }

    /*
     * See if we've got any conditional envariable-controlled logging decisions
     * to make.
     */
    if (cls->condition_var != NULL) {
        envar = cls->condition_var;
        if (*envar != '!') {
            if (apr_table_get(r->subprocess_env, envar) == NULL) {
                return DECLINED;
            }
        }
        else {
            if (apr_table_get(r->subprocess_env, &envar[1]) != NULL) {
                return DECLINED;
            }
        }
    }

    format = cls->format ? cls->format : default_format;

    strs = apr_palloc(r->pool, sizeof(char *) * (format->nelts));
    strl = apr_palloc(r->pool, sizeof(int) * (format->nelts));
    items = (log_format_item *) format->elts;

    orig = r;
    while (orig->prev) {
        orig = orig->prev;
    }
    while (r->next) {
        r = r->next;
    }

    for (i = 0; i < format->nelts; ++i) {
        strs[i] = process_item(r, orig, &items[i]);
    }

    for (i = 0; i < format->nelts; ++i) {
        len += strl[i] = strlen(strs[i]);
    }
    if (!log_writer) {
        ap_log_rerror(APLOG_MARK, APLOG_ERR, APR_EGENERAL, r,
                "log writer isn't correctly setup");
         return HTTP_INTERNAL_SERVER_ERROR;
    }
    rv = log_writer(r, cls->log_writer, strs, strl, format->nelts, len);
    /* xxx: do we return an error on log_writer? */
    return OK;
}

static int multi_log_transaction(request_rec *r)
{
    multi_log_state *mls = ap_get_module_config(r->server->module_config,
                                                &log_config_module);
    config_log_state *clsarray;
    int i;

    /*
     * Log this transaction..
     */
    if (mls->config_logs->nelts) {
        clsarray = (config_log_state *) mls->config_logs->elts;
        for (i = 0; i < mls->config_logs->nelts; ++i) {
            config_log_state *cls = &clsarray[i];

            config_log_transaction(r, cls, mls->default_format);
        }
    }
    else if (mls->server_config_logs) {
        clsarray = (config_log_state *) mls->server_config_logs->elts;
        for (i = 0; i < mls->server_config_logs->nelts; ++i) {
            config_log_state *cls = &clsarray[i];

            config_log_transaction(r, cls, mls->default_format);
        }
    }

    return OK;
}

/*****************************************************************
 *
 * Module glue...
 */

static void *make_config_log_state(apr_pool_t *p, server_rec *s)
{
    multi_log_state *mls;

    mls = (multi_log_state *) apr_palloc(p, sizeof(multi_log_state));
    mls->config_logs = apr_array_make(p, 1, sizeof(config_log_state));
    mls->default_format_string = NULL;
    mls->default_format = NULL;
    mls->server_config_logs = NULL;
    mls->formats = apr_table_make(p, 4);
    apr_table_setn(mls->formats, "CLF", DEFAULT_LOG_FORMAT);

    return mls;
}

/*
 * Use the merger to simply add a pointer from the vhost log state
 * to the log of logs specified for the non-vhost configuration.  Make sure
 * vhosts inherit any globally-defined format names.
 */

static void *merge_config_log_state(apr_pool_t *p, void *basev, void *addv)
{
    multi_log_state *base = (multi_log_state *) basev;
    multi_log_state *add = (multi_log_state *) addv;

    add->server_config_logs = base->config_logs;
    if (!add->default_format) {
        add->default_format_string = base->default_format_string;
        add->default_format = base->default_format;
    }
    add->formats = apr_table_overlay(p, base->formats, add->formats);

    return add;
}

/*
 * Set the default logfile format, or define a nickname for a format string.
 */
static const char *log_format(cmd_parms *cmd, void *dummy, const char *fmt,
                              const char *name)
{
    const char *err_string = NULL;
    multi_log_state *mls = ap_get_module_config(cmd->server->module_config,
                                                &log_config_module);

    /*
     * If we were given two arguments, the second is a name to be given to the
     * format.  This syntax just defines the nickname - it doesn't actually
     * make the format the default.
     */
    if (name != NULL) {
        parse_log_string(cmd->pool, fmt, &err_string);
        if (err_string == NULL) {
            apr_table_setn(mls->formats, name, fmt);
        }
    }
    else {
        mls->default_format_string = fmt;
        mls->default_format = parse_log_string(cmd->pool, fmt, &err_string);
    }
    return err_string;
}


static const char *add_custom_log(cmd_parms *cmd, void *dummy, const char *fn,
                                  const char *fmt, const char *envclause)
{
    const char *err_string = NULL;
    multi_log_state *mls = ap_get_module_config(cmd->server->module_config,
                                                &log_config_module);
    config_log_state *cls;

    cls = (config_log_state *) apr_array_push(mls->config_logs);
    cls->condition_var = NULL;
    if (envclause != NULL) {
        if (strncasecmp(envclause, "env=", 4) != 0) {
            return "error in condition clause";
        }
        if ((envclause[4] == '\0')
            || ((envclause[4] == '!') && (envclause[5] == '\0'))) {
            return "missing environment variable name";
        }
        cls->condition_var = apr_pstrdup(cmd->pool, &envclause[4]);
    }

    cls->fname = fn;
    cls->format_string = fmt;
    if (fmt == NULL) {
        cls->format = NULL;
    }
    else {
        cls->format = parse_log_string(cmd->pool, fmt, &err_string);
    }
    cls->log_writer = NULL;

    return err_string;
}

static const char *set_transfer_log(cmd_parms *cmd, void *dummy,
                                    const char *fn)
{
    return add_custom_log(cmd, dummy, fn, NULL, NULL);
}

static const char *set_cookie_log(cmd_parms *cmd, void *dummy, const char *fn)
{
    return add_custom_log(cmd, dummy, fn, "%{Cookie}n \"%r\" %t", NULL);
}

static const char *set_buffered_logs_on(cmd_parms *parms, void *dummy, int flag)
{
    buffered_logs = flag;
    if (buffered_logs) {
        ap_log_set_writer_init(ap_buffered_log_writer_init);
        ap_log_set_writer(ap_buffered_log_writer);
    }
    return NULL;
}
static const command_rec config_log_cmds[] =
{
AP_INIT_TAKE23("CustomLog", add_custom_log, NULL, RSRC_CONF,
     "a file name, a custom log format string or format name, "
     "and an optional \"env=\" clause (see docs)"),
AP_INIT_TAKE1("TransferLog", set_transfer_log, NULL, RSRC_CONF,
     "the filename of the access log"),
AP_INIT_TAKE12("LogFormat", log_format, NULL, RSRC_CONF,
     "a log format string (see docs) and an optional format name"),
AP_INIT_TAKE1("CookieLog", set_cookie_log, NULL, RSRC_CONF,
     "the filename of the cookie log"),
AP_INIT_FLAG("BufferedLogs", set_buffered_logs_on, NULL, RSRC_CONF,
                 "Enable Buffered Logging (experimental)"),
    {NULL}
};

static config_log_state *open_config_log(server_rec *s, apr_pool_t *p,
                                         config_log_state *cls,
                                         apr_array_header_t *default_format)
{
    if (cls->log_writer != NULL) {
        return cls;             /* virtual config shared w/main server */
    }

    if (cls->fname == NULL) {
        return cls;             /* Leave it NULL to decline.  */
    }
    
    cls->log_writer = log_writer_init(p, s, cls->fname);
    if (cls->log_writer == NULL)
        return NULL; 

    return cls;
}

static int open_multi_logs(server_rec *s, apr_pool_t *p)