view src/os/win32/ngx_service.c @ 9300:5be23505292b

SSI: fixed incorrect or duplicate stub output. Following 3518:eb3aaf8bd2a9 (0.8.37), r->request_output is only set if there are data in the first buffer sent in the subrequest. As a result, following the change mentioned this flag cannot be used to prevent duplicate ngx_http_ssi_stub_output() calls, since it is not set if there was already some output, but the first buffer was empty. Still, when there are multiple subrequests, even an empty subrequest response might be delayed by the postpone filter, leading to a second call of ngx_http_ssi_stub_output() during finalization from ngx_http_writer() the subreqest buffers are released by the postpone filter. Since r->request_output is not set after the first call, this resulted in duplicate stub output. Additionally, checking only the first buffer might be wrong in some unusual cases. For example, the first buffer might be empty if $r->flush() is called before printing any data in the embedded Perl module. Depending on the postpone_output value and corresponding sizes, this issue can result in either duplicate or unexpected stub output, or "zero size buf in writer" alerts. Following 8124:f5515e727656 (1.23.4), it became slightly easier to reproduce the issue, as empty static files and empty cache items now result in a response with an empty buffer. Before the change, an empty proxied response can be used to reproduce the issue. Fix is check all buffers and set r->request_output if any non-empty buffers are sent. This ensures that all unusual cases of non-empty responses are covered, and also that r->request_output will be set after the first stub output, preventing duplicate output. Reported by Jan Gassen.
author Maxim Dounin <mdounin@mdounin.ru>
date Thu, 04 Jul 2024 17:41:28 +0300
parents a1caf3989b49
children
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/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */



#define NGX_SERVICE_CONTROL_SHUTDOWN   128
#define NGX_SERVICE_CONTROL_REOPEN     129


SERVICE_TABLE_ENTRY st[] = {
    { "nginx", service_main },
    { NULL, NULL }
};


ngx_int_t
ngx_service(ngx_log_t *log)
{
    /* primary thread */

    /* StartServiceCtrlDispatcher() should be called within 30 seconds */

    if (StartServiceCtrlDispatcher(st) == 0) {
        ngx_log_error(NGX_LOG_EMERG, log, ngx_errno,
                      "StartServiceCtrlDispatcher() failed");
        return NGX_ERROR;
    }

    return NGX_OK;
}


void
service_main(u_int argc, char **argv)
{
    SERVICE_STATUS         status;
    SERVICE_STATUS_HANDLE  service;

    /* thread spawned by SCM */

    service = RegisterServiceCtrlHandlerEx("nginx", service_handler, ctx);
    if (service == INVALID_HANDLE_VALUE) {
        ngx_log_error(NGX_LOG_EMERG, log, ngx_errno,
                      "RegisterServiceCtrlHandlerEx() failed");
        return;
    }

    status.dwServiceType = SERVICE_WIN32_OWN_PROCESS;
    status.dwCurrentState = SERVICE_START_PENDING;
    status.dwControlsAccepted = SERVICE_ACCEPT_STOP
                                |SERVICE_ACCEPT_PARAMCHANGE;
    status.dwWin32ExitCode = NO_ERROR;
    status.dwServiceSpecificExitCode = 0;
    status.dwCheckPoint = 1;
    status.dwWaitHint = 2000;

    /* SetServiceStatus() should be called within 80 seconds */

    if (SetServiceStatus(service, &status) == 0) {
        ngx_log_error(NGX_LOG_EMERG, log, ngx_errno,
                      "SetServiceStatus() failed");
        return;
    }

    /* init */

    status.dwCurrentState = SERVICE_RUNNING;
    status.dwCheckPoint = 0;
    status.dwWaitHint = 0;

    if (SetServiceStatus(service, &status) == 0) {
        ngx_log_error(NGX_LOG_EMERG, log, ngx_errno,
                      "SetServiceStatus() failed");
        return;
    }

    /* call master or worker loop */

    /*
     * master should use event notification and look status
     * single should use iocp to get notifications from service handler
     */

}


u_int
service_handler(u_int control, u_int type, void *data, void *ctx)
{
    /* primary thread */

    switch (control) {

    case SERVICE_CONTROL_INTERROGATE:
        status = NGX_IOCP_INTERROGATE;
        break;

    case SERVICE_CONTROL_STOP:
        status = NGX_IOCP_STOP;
        break;

    case SERVICE_CONTROL_PARAMCHANGE:
        status = NGX_IOCP_RECONFIGURE;
        break;

    case NGX_SERVICE_CONTROL_SHUTDOWN:
        status = NGX_IOCP_REOPEN;
        break;

    case NGX_SERVICE_CONTROL_REOPEN:
        status = NGX_IOCP_REOPEN;
        break;

    default:
        return ERROR_CALL_NOT_IMPLEMENTED;
    }

    if (ngx_single) {
        if (PostQueuedCompletionStatus(iocp, ... status, ...) == 0) {
            err = ngx_errno;
            ngx_log_error(NGX_LOG_ALERT, log, err,
                          "PostQueuedCompletionStatus() failed");
            return err;
        }

    } else {
        Event
    }

    return NO_ERROR;
}