mpm_winnt.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。

        EVENT_MODIFY_STATE | SYNCHRONIZE, FALSE, 0)) {
        ap_log_error(APLOG_MARK, APLOG_CRIT, apr_get_os_error(), ap_server_conf,
                     "Parent: Unable to duplicate the ready event handle for the child");
        return -1;
    }
    if ((rv = apr_file_write_full(child_in, &hDup, sizeof(hDup), &BytesWritten))
            != APR_SUCCESS) {
        ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf,
                     "Parent: Unable to send the exit event handle to the child");
        return -1;
    }
    if (!DuplicateHandle(hCurrentProcess, child_exit_event, hProcess, &hDup,
                         EVENT_MODIFY_STATE | SYNCHRONIZE, FALSE, 0)) {
        ap_log_error(APLOG_MARK, APLOG_CRIT, apr_get_os_error(), ap_server_conf,
                     "Parent: Unable to duplicate the exit event handle for the child");
        return -1;
    }
    if ((rv = apr_file_write_full(child_in, &hDup, sizeof(hDup), &BytesWritten))
            != APR_SUCCESS) {
        ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf,
                     "Parent: Unable to send the exit event handle to the child");
        return -1;
    }
    if ((rv = apr_os_proc_mutex_get(&os_start, child_start_mutex)) != APR_SUCCESS) {
        ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf,
                     "Parent: Unable to retrieve the start mutex for the child");
        return -1;
    }
    if (!DuplicateHandle(hCurrentProcess, os_start, hProcess, &hDup,
                         SYNCHRONIZE, FALSE, 0)) {
        ap_log_error(APLOG_MARK, APLOG_CRIT, apr_get_os_error(), ap_server_conf,
                     "Parent: Unable to duplicate the start mutex to the child");
        return -1;
    }
    if ((rv = apr_file_write_full(child_in, &hDup, sizeof(hDup), &BytesWritten))
            != APR_SUCCESS) {
        ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf,
                     "Parent: Unable to send the start mutex to the child");
        return -1;
    }
    if ((rv = apr_os_shm_get(&hScore, scoreboard_shm)) != APR_SUCCESS) {
        ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf,
                     "Parent: Unable to retrieve the scoreboard handle for the child");
        return -1;
    }
    if (!DuplicateHandle(hCurrentProcess, hScore, hProcess, &hDup,
                         FILE_MAP_READ | FILE_MAP_WRITE, FALSE, 0)) {
        ap_log_error(APLOG_MARK, APLOG_CRIT, apr_get_os_error(), ap_server_conf,
                     "Parent: Unable to duplicate the scoreboard handle to the child");
        return -1;
    }
    if ((rv = apr_file_write_full(child_in, &hDup, sizeof(hDup), &BytesWritten))
            != APR_SUCCESS) {
        ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf,
                     "Parent: Unable to send the scoreboard handle to the child");
        return -1;
    }

    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf,
                 "Parent: Sent the scoreboard to the child");
    return 0;
}


/* 
 * get_listeners_from_parent()
 * The listen sockets are opened in the parent. This function, which runs
 * exclusively in the child process, receives them from the parent and
 * makes them availeble in the child.
 */
void get_listeners_from_parent(server_rec *s)
{
    WSAPROTOCOL_INFO WSAProtocolInfo;
    HANDLE pipe;
    ap_listen_rec *lr;
    DWORD BytesRead;
    int lcnt = 0;
    SOCKET nsd;

    /* Set up a default listener if necessary */
    if (ap_listeners == NULL) {
        ap_listen_rec *lr;
        lr = apr_palloc(s->process->pool, sizeof(ap_listen_rec));
        lr->sd = NULL;
        lr->next = ap_listeners;
        ap_listeners = lr;
    }

    /* Open the pipe to the parent process to receive the inherited socket
     * data. The sockets have been set to listening in the parent process.
     */
    pipe = GetStdHandle(STD_INPUT_HANDLE);

    for (lr = ap_listeners; lr; lr = lr->next, ++lcnt) {
        if (!ReadFile(pipe, &WSAProtocolInfo, sizeof(WSAPROTOCOL_INFO), 
                      &BytesRead, (LPOVERLAPPED) NULL)) {
            ap_log_error(APLOG_MARK, APLOG_CRIT, apr_get_os_error(), ap_server_conf,
                         "setup_inherited_listeners: Unable to read socket data from parent");
            exit(APEXIT_CHILDINIT);
        }
        nsd = WSASocket(FROM_PROTOCOL_INFO, FROM_PROTOCOL_INFO, FROM_PROTOCOL_INFO,
                        &WSAProtocolInfo, 0, 0);
        if (nsd == INVALID_SOCKET) {
            ap_log_error(APLOG_MARK, APLOG_CRIT, apr_get_netos_error(), ap_server_conf,
                         "Child %d: setup_inherited_listeners(), WSASocket failed to open the inherited socket.", my_pid);
            exit(APEXIT_CHILDINIT);
        }

        if (osver.dwPlatformId == VER_PLATFORM_WIN32_WINDOWS) {
            HANDLE hProcess = GetCurrentProcess();
            HANDLE dup;
            if (DuplicateHandle(hProcess, (HANDLE) nsd, hProcess, &dup, 
                                0, FALSE, DUPLICATE_SAME_ACCESS)) {
                closesocket(nsd);
                nsd = (SOCKET) dup;
            }
        }
        else {
            /* A different approach.  Many users report errors such as 
             * (32538)An operation was attempted on something that is not 
             * a socket.  : Parent: WSADuplicateSocket failed...
             *
             * This appears that the duplicated handle is no longer recognized
             * as a socket handle.  SetHandleInformation should overcome that
             * problem by not altering the handle identifier.  But this won't
             * work on 9x - it's unsupported.
             */
            if (!SetHandleInformation((HANDLE)nsd, HANDLE_FLAG_INHERIT, 0)) {
                ap_log_error(APLOG_MARK, APLOG_ERR, apr_get_os_error(), ap_server_conf,
                             "set_listeners_noninheritable: SetHandleInformation failed.");
            }
        }
        apr_os_sock_put(&lr->sd, &nsd, s->process->pool);
    }

    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf,
                 "Child %d: retrieved %d listeners from parent", my_pid, lcnt);
}


static int send_listeners_to_child(apr_pool_t *p, DWORD dwProcessId, 
                                   apr_file_t *child_in)
{
    apr_status_t rv;
    int lcnt = 0;
    ap_listen_rec *lr;
    LPWSAPROTOCOL_INFO  lpWSAProtocolInfo;
    DWORD BytesWritten;

    /* Run the chain of open sockets. For each socket, duplicate it 
     * for the target process then send the WSAPROTOCOL_INFO 
     * (returned by dup socket) to the child.
     */
    for (lr = ap_listeners; lr; lr = lr->next, ++lcnt) {
        int nsd;
        lpWSAProtocolInfo = apr_pcalloc(p, sizeof(WSAPROTOCOL_INFO));
        apr_os_sock_get(&nsd,lr->sd);
        ap_log_error(APLOG_MARK, APLOG_INFO, APR_SUCCESS, ap_server_conf,
                     "Parent: Duplicating socket %d and sending it to child process %d", 
                     nsd, dwProcessId);
        if (WSADuplicateSocket(nsd, dwProcessId,
                               lpWSAProtocolInfo) == SOCKET_ERROR) {
            ap_log_error(APLOG_MARK, APLOG_CRIT, apr_get_netos_error(), ap_server_conf,
                         "Parent: WSADuplicateSocket failed for socket %d. Check the FAQ.", lr->sd );
            return -1;
        }

        if ((rv = apr_file_write_full(child_in, lpWSAProtocolInfo, 
                                      sizeof(WSAPROTOCOL_INFO), &BytesWritten))
                != APR_SUCCESS) {
            ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf,
                         "Parent: Unable to write duplicated socket %d to the child.", lr->sd );
            return -1;
        }
    }

    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf,
                 "Parent: Sent %d listeners to child %d", lcnt, dwProcessId);
    return 0;
}

enum waitlist_e {
    waitlist_ready = 0,
    waitlist_term = 1
};

static int create_process(apr_pool_t *p, HANDLE *child_proc, HANDLE *child_exit_event, 
                          DWORD *child_pid)
{
    /* These NEVER change for the lifetime of this parent 
     */
    static char **args = NULL;
    static char **env = NULL;
    static char pidbuf[28];

    apr_status_t rv;
    apr_pool_t *ptemp;
    apr_procattr_t *attr;
    apr_file_t *child_out;
    apr_file_t *child_err;
    apr_proc_t new_child;
    HANDLE hExitEvent;
    HANDLE waitlist[2];  /* see waitlist_e */
    char *cmd;
    char *cwd;

    apr_pool_sub_make(&ptemp, p, NULL);

    /* Build the command line. Should look something like this:
     * C:/apache/bin/apache.exe -f ap_server_confname 
     * First, get the path to the executable...
     */
    apr_procattr_create(&attr, ptemp);
    apr_procattr_cmdtype_set(attr, APR_PROGRAM);
    apr_procattr_detach_set(attr, 1);
    if (((rv = apr_filepath_get(&cwd, 0, ptemp)) != APR_SUCCESS)
           || ((rv = apr_procattr_dir_set(attr, cwd)) != APR_SUCCESS)) {
        ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf,
                     "Parent: Failed to get the current path");
    }

    if (!args) {
        /* Build the args array, only once since it won't change 
         * for the lifetime of this parent process.
         */
        if ((rv = ap_os_proc_filepath(&cmd, ptemp))
                != APR_SUCCESS) {
            ap_log_error(APLOG_MARK, APLOG_CRIT, ERROR_BAD_PATHNAME, ap_server_conf,
                         "Parent: Failed to get full path of %s", 
                         ap_server_conf->process->argv[0]);
            apr_pool_destroy(ptemp);
            return -1;
        }
        
        args = malloc((ap_server_conf->process->argc + 1) * sizeof (char*));
        memcpy(args + 1, ap_server_conf->process->argv + 1, 
               (ap_server_conf->process->argc - 1) * sizeof (char*));
        args[0] = malloc(strlen(cmd) + 1);
        strcpy(args[0], cmd);
        args[ap_server_conf->process->argc] = NULL;
    }
    else {
        cmd = args[0];
    }

    /* Create a pipe to send handles to the child */
    if ((rv = apr_procattr_io_set(attr, APR_FULL_BLOCK, 
                                  APR_NO_PIPE, APR_NO_PIPE)) != APR_SUCCESS) {
        ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf,
                        "Parent: Unable to create child stdin pipe.\n");
        apr_pool_destroy(ptemp);
        return -1;
    }

    /* Open a null handle to soak info from the child */
    if (((rv = apr_file_open(&child_out, "NUL", APR_READ | APR_WRITE, 
                             APR_OS_DEFAULT, ptemp)) != APR_SUCCESS)
        || ((rv = apr_procattr_child_out_set(attr, child_out, NULL)) 
                != APR_SUCCESS)) {
        ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf,
                        "Parent: Unable to connect child stdout to NUL.\n");
        apr_pool_destroy(ptemp);
        return -1;
    }

    /* Connect the child's initial stderr to our main server error log 
     * or share our own stderr handle.
     */
    if (ap_server_conf->error_log) {
        child_err = ap_server_conf->error_log;
    }
    else {
        rv = apr_file_open_stderr(&child_err, ptemp);
    }
    if (rv == APR_SUCCESS) {
        if ((rv = apr_procattr_child_err_set(attr, child_err, NULL))
                != APR_SUCCESS) {
            ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf,
                            "Parent: Unable to connect child stderr.\n");
            apr_pool_destroy(ptemp);
            return -1;
        }
    }

    /* Create the child_ready_event */
    waitlist[waitlist_ready] = CreateEvent(NULL, TRUE, FALSE, NULL);
    if (!waitlist[waitlist_ready]) {
        ap_log_error(APLOG_MARK, APLOG_CRIT, apr_get_os_error(), ap_server_conf,
                     "Parent: Could not create ready event for child process");
        apr_pool_destroy (ptemp);
        return -1;
    }

    /* Create the child_exit_event */
    hExitEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
    if (!hExitEvent) {
        ap_log_error(APLOG_MARK, APLOG_CRIT, apr_get_os_error(), ap_server_conf,
                     "Parent: Could not create exit event for child process");
        apr_pool_destroy(ptemp);
        CloseHandle(waitlist[waitlist_ready]);
        return -1;
    }

    if (!env) 
    {
        /* Build the env array, only once since it won't change 
         * for the lifetime of this parent process.
         */
        int envc;
        for (envc = 0; _environ[envc]; ++envc) {
            ;
        }
        env = malloc((envc + 2) * sizeof (char*));
        memcpy(env, _environ, envc * sizeof (char*));
        apr_snprintf(pidbuf, sizeof(pidbuf), "AP_PARENT_PID=%i", parent_pid);
        env[envc] = pidbuf;
        env[envc + 1] = NULL;
    }

    rv = apr_proc_create(&new_child, cmd, args, env, attr, ptemp);
    if (rv != APR_SUCCESS) {
        ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf,
                     "Parent: Failed to create the child process.");
        apr_pool_destroy(ptemp);
        CloseHandle(hExitEvent);
        CloseHandle(waitlist[waitlist_ready]);
        CloseHandle(new_child.hproc);
        return -1;
    }

    ap_log_error(APLOG_MARK, APLOG_NOTICE, APR_SUCCESS, ap_server_conf,
                 "Parent: Created child process %d", new_child.pid);

    if (send_handles_to_child(ptemp, waitlist[waitlist_ready], hExitEvent,
                              start_mutex, ap_scoreboard_shm,
                              new_child.hproc, new_child.in)) {
        /*
         * This error is fatal, mop up the child and move on
         * We toggle the child's exit event to cause this child 
         * to quit even as it is attempting to start.
         */
        SetEvent(hExitEvent);
        apr_pool_destroy(ptemp);
        CloseHandle(hExitEvent);
        CloseHandle(waitlist[waitlist_ready]);
        CloseHandle(new_child.hproc);
        return -1;
    }

    /* Important:
     * Give the child process a chance to run before dup'ing the sockets.
     * We have already set the listening sockets noninheritable, but if 
     * WSADuplicateSocket runs before the child process initializes
     * the listeners will be inherited anyway.
     */
    waitlist[waitlist_term] = new_child.hproc;
    rv = WaitForMultipleObjects(2, waitlist, FALSE, INFINITE);
    CloseHandle(waitlist[waitlist_ready]);
    if (rv != WAIT_OBJECT_0) {
        /* 
         * Outch... that isn't a ready signal. It's dead, Jim!
         */
        SetEvent(hExitEvent);
        apr_pool_destroy(ptemp);
        CloseHandle(hExitEvent);
        CloseHandle(new_child.hproc);
        return -1;
    }

    if (send_listeners_to_child(ptemp, new_child.pid, new_child.in)) {
        /*
         * This error is fatal, mop up the child and move on
         * We toggle the child's exit event to cause this child 
         * to quit even as it is attempting to start.
         */
        SetEvent(hExitEvent);
        apr_pool_destroy(ptemp);
        CloseHandle(hExitEvent);
        CloseHandle(new_child.hproc);
        return -1;
    }

    *child_exit_event = hExitEvent;
    *child_proc = new_child.hproc;
    *child_pid = new_child.pid;

    return 0;
}

/***********************************************************************
 * master_main()
 * master_main() runs in the parent process.  It creates the child 
 * process which handles HTTP requests then waits on one of three 
 * events:
 *
 * restart_event
 * -------------
 * The restart event causes master_main to start a new child process and
 * tells the old child process to exit (by setting the child_exit_event).
 * The restart event is set as a result of one of the following:
 * 1. An apache -k restart command on the command line
 * 2. A command received from Windows service manager which gets 
 *    translated into an ap_signal_parent(SIGNAL_PARENT_RESTART)
 *    call by code in service.c.
 * 3. The child process calling ap_signal_parent(SIGNAL_PARENT_RESTART)
 *    as a result of hitting MaxRequestsPerChild.
 *
 * shutdown_event 
 * --------------
 * The shutdown event causes master_main to tell the child process to 
 * exit and that the server is shutting down. The shutdown event is
 * set as a result of one of the following:
 * 1. An apache -k shutdown command on the command line
 * 2. A command received from Windows service manager which gets
 *    translated into an ap_signal_parent(SIGNAL_PARENT_SHUTDOWN)
 *    call by code in service.c.
 *
 * child process handle
 * --------------------
 * The child process handle will be signaled if the child process 
 * exits for any reason. In a normal running server, the signaling