lib/daemon-windows.c

   1 /*
   2  * Copyright (c) 2014 Nicira, Inc.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #include <config.h>
  18 #include "daemon.h"
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include "poll-loop.h"
  22 #include "vlog.h"
  23
  24 VLOG_DEFINE_THIS_MODULE(daemon);
  25
  26 static bool detach;             /* Was --service specified? */
  27 static bool detached;           /* Have we already detached? */
  28
  29 /* --service-monitor: Should the service be restarted if it dies
  30  * unexpectedly? */
  31 static bool monitor;
  32
  33 /* Handle to the Services Manager and the created service. */
  34 static SC_HANDLE manager, service;
  35
  36 /* Handle to the status information structure for the current service. */
  37 static SERVICE_STATUS_HANDLE hstatus;
  38
  39 /* Hold the service's current status. */
  40 static SERVICE_STATUS service_status;
  41
  42 /* Handle to an event object used to wakeup from poll_block(). */
  43 static HANDLE wevent;
  44
  45 /* Hold the arguments sent to the main function. */
  46 static int sargc;
  47 static char ***sargvp;
  48
  49 static void check_service(void);
  50 static void handle_scm_callback(void);
  51 static void init_service_status(void);
  52 static void set_config_failure_actions(void);
  53
  54 extern int main(int argc, char *argv[]);
  55
  56 void
  57 daemon_usage(void)
  58 {
  59     printf(
  60         "\nService options:\n"
  61         "  --service               run in background as a service.\n"
  62         "  --service-monitor       restart the service in case of an "
  63                                    "unexpected failure. \n",
  64         ovs_rundir(), program_name);
  65 }
  66
  67 /* Registers the call-back and configures the actions in case of a failure
  68  * with the Windows services manager. */
  69 void
  70 service_start(int *argcp, char **argvp[])
  71 {
  72     int argc = *argcp;
  73     char **argv = *argvp;
  74     int i;
  75     SERVICE_TABLE_ENTRY service_table[] = {
  76         {(LPTSTR)program_name, (LPSERVICE_MAIN_FUNCTION)main},
  77         {NULL, NULL}
  78     };
  79
  80     /* 'detached' is 'false' when service_start() is called the first time.
  81      * It is 'true', when it is called the second time by the Windows services
  82      * manager. */
  83     if (detached) {
  84         init_service_status();
  85
  86         wevent = CreateEvent(NULL, TRUE, FALSE, NULL);
  87         if (!wevent) {
  88             char *msg_buf = ovs_lasterror_to_string();
  89             VLOG_FATAL("Failed to create a event (%s).", msg_buf);
  90         }
  91
  92         poll_fd_wait_event(0, wevent, POLLIN);
  93
  94         /* Register the control handler. This function is called by the service
  95          * manager to stop the service. */
  96         hstatus = RegisterServiceCtrlHandler(program_name,
  97                                          (LPHANDLER_FUNCTION)control_handler);
  98         if (!hstatus) {
  99             char *msg_buf = ovs_lasterror_to_string();
 100             VLOG_FATAL("Failed to register the service control handler (%s).",
 101                         msg_buf);
 102         }
 103
 104         if (monitor) {
 105             set_config_failure_actions();
 106         }
 107
 108         /* When the service control manager does the call back, it does not
 109          * send the same arguments as sent to the main function during the
 110          * service start. So, use the arguments passed over during the first
 111          * time. */
 112         *argcp = sargc;
 113         *argvp = *sargvp;
 114
 115         /* XXX: Windows implementation cannot have a unixctl commands in the
 116         * traditional sense of unix domain sockets. If an implementation is
 117         * done that involves 'unixctl' vlog commands the following call is
 118         * needed to make sure that the unixctl commands for vlog get
 119         * registered in a daemon, even before the first log message. */
 120         vlog_init();
 121
 122         return;
 123     }
 124
 125     assert_single_threaded();
 126
 127     /* A reference to arguments passed to the main function the first time.
 128      * We need it after the call-back from service control manager. */
 129     sargc = argc;
 130     sargvp = argvp;
 131
 132     /* We are only interested in the '--service' and '--service-monitor'
 133      * options before the call-back from the service control manager. */
 134     for (i = 0; i < argc; i ++) {
 135         if (!strcmp(argv[i], "--service")) {
 136             detach = true;
 137         } else if (!strcmp(argv[i], "--service-monitor")) {
 138             monitor = true;
 139         }
 140     }
 141
 142     /* If '--service' is not a command line option, run in foreground. */
 143     if (!detach) {
 144         return;
 145     }
 146
 147     /* If we have been configured to run as a service, then that service
 148      * should already have been created either manually or through a start up
 149      * script. */
 150     check_service();
 151
 152     detached = true;
 153
 154     /* StartServiceCtrlDispatcher blocks and returns after the service is
 155      * stopped. */
 156     if (!StartServiceCtrlDispatcher(service_table)) {
 157         char *msg_buf = ovs_lasterror_to_string();
 158         VLOG_FATAL("Failed at StartServiceCtrlDispatcher (%s)", msg_buf);
 159     }
 160     exit(0);
 161 }
 162
 163 /* This function is registered with the Windows services manager through
 164  * a call to RegisterServiceCtrlHandler() and will be called by the Windows
 165  * services manager asynchronously to stop the service. */
 166 void
 167 control_handler(DWORD request)
 168 {
 169     switch (request) {
 170     case SERVICE_CONTROL_STOP:
 171     case SERVICE_CONTROL_SHUTDOWN:
 172         service_status.dwCurrentState = SERVICE_STOPPED;
 173         service_status.dwWin32ExitCode = NO_ERROR;
 174         SetEvent(wevent);
 175         break;
 176
 177     default:
 178         break;
 179     }
 180 }
 181
 182 /* Return 'true' if the Windows services manager has called the
 183  * control_handler() and asked the program to terminate. */
 184 bool
 185 should_service_stop(void)
 186 {
 187     if (detached) {
 188         if (service_status.dwCurrentState != SERVICE_RUNNING) {
 189             return true;
 190         } else {
 191             poll_fd_wait_event(0, wevent, POLLIN);
 192         }
 193     }
 194     return false;
 195 }
 196
 197 /* Set the service as stopped. The control manager will terminate the
 198  * service soon after this call. Hence, this should ideally be the last
 199  * call before termination. */
 200 void
 201 service_stop()
 202 {
 203     ResetEvent(wevent);
 204     CloseHandle(wevent);
 205
 206     service_status.dwCurrentState = SERVICE_STOPPED;
 207     service_status.dwWin32ExitCode = NO_ERROR;
 208     SetServiceStatus(hstatus, &service_status);
 209 }
 210
 211 /* Call this function to signal that the daemon is ready. init_service()
 212  * or control_handler() has already initalized/set the
 213  * service_status.dwCurrentState .*/
 214 static void
 215 service_complete(void)
 216 {
 217     if (hstatus) {
 218         SetServiceStatus(hstatus, &service_status);
 219     }
 220 }
 221
 222 /* Check whether 'program_name' has been created as a service. */
 223 static void
 224 check_service()
 225 {
 226     /* Establish a connection to the local service control manager. */
 227     manager = OpenSCManager(NULL, NULL, SC_MANAGER_ENUMERATE_SERVICE);
 228     if (!manager) {
 229         char *msg_buf = ovs_lasterror_to_string();
 230         VLOG_FATAL("Failed to open the service control manager (%s).",
 231                    msg_buf);
 232     }
 233
 234     service = OpenService(manager, program_name, SERVICE_ALL_ACCESS);
 235     if (!service) {
 236         char *msg_buf = ovs_lasterror_to_string();
 237         VLOG_FATAL("Failed to open service (%s).", msg_buf);
 238     }
 239 }
 240
 241 /* Service status of a service can be checked asynchronously through
 242  * tools like 'sc' or through Windows services manager and is set
 243  * through a call to SetServiceStatus(). */
 244 static void
 245 init_service_status()
 246 {
 247     /* The service runs in its own process. */
 248     service_status.dwServiceType = SERVICE_WIN32_OWN_PROCESS;
 249
 250     /* The control codes the service accepts. */
 251     service_status.dwControlsAccepted = SERVICE_ACCEPT_STOP |
 252                                             SERVICE_ACCEPT_SHUTDOWN;
 253
 254     /* Initialize the current state as SERVICE_RUNNING. */
 255     service_status.dwCurrentState = SERVICE_RUNNING;
 256
 257     /* The exit code to indicate if there was an error. */
 258     service_status.dwWin32ExitCode = NO_ERROR;
 259
 260     /* The checkpoint value the service increments periodically. Set as 0
 261      * as we do not plan to periodically increment the value. */
 262     service_status.dwCheckPoint = 0;
 263
 264     /* The estimated time required for the stop operation in ms. */
 265     service_status.dwWaitHint = 1000;
 266 }
 267
 268 /* In case of an unexpected termination, configure the action to be
 269  * taken. */
 270 static void
 271 set_config_failure_actions()
 272 {
 273     /* In case of a failure, restart the process the first two times
 274      * After 'dwResetPeriod', the failure count is reset. */
 275     SC_ACTION fail_action[3] = {
 276         {SC_ACTION_RESTART, 0},
 277         {SC_ACTION_RESTART, 0},
 278         {SC_ACTION_NONE, 0}
 279     };
 280     SERVICE_FAILURE_ACTIONS service_fail_action;
 281
 282     /* Reset failure count after (in seconds). */
 283     service_fail_action.dwResetPeriod = 10;
 284
 285     /* Reboot message. */
 286     service_fail_action.lpRebootMsg = NULL;
 287
 288     /* The command line of the process. */
 289     service_fail_action.lpCommand = NULL;
 290
 291     /* Number of elements in 'fail_actions'. */
 292     service_fail_action.cActions = sizeof(fail_action)/sizeof(fail_action[0]);
 293
 294     /* A pointer to an array of SC_ACTION structures. */
 295     service_fail_action.lpsaActions = fail_action;
 296
 297     if (!ChangeServiceConfig2(service, SERVICE_CONFIG_FAILURE_ACTIONS,
 298                               &service_fail_action)) {
 299         char *msg_buf = ovs_lasterror_to_string();
 300         VLOG_FATAL("Failed to configure service fail actions (%s).", msg_buf);
 301     }
 302 }
 303
 304 \f
 305 /* Stub functions to handle daemonize related calls in non-windows platform. */
 306 bool
 307 get_detach()
 308 {
 309     return false;
 310 }
 311
 312 void
 313 daemon_save_fd(int fd OVS_UNUSED)
 314 {
 315 }
 316
 317 void
 318 daemonize(void)
 319 {
 320 }
 321
 322 void daemonize_start(void)
 323 {
 324 }
 325
 326 void
 327 daemonize_complete(void)
 328 {
 329     service_complete();
 330 }