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From p..@hyperreal.org
Subject cvs commit: apache-1.3/src/main http_main.c
Date Tue, 06 Oct 1998 15:41:46 GMT
pcs         98/10/06 08:41:46

  Modified:    src/main http_main.c
  Log:
  WIN32: Add new options to let Apache signal itself to shutdown or
  restart. The option is -k, used like this:
  
    -k shutdown
    -k restart
  
  This lets people signal Apache on Win95 systems (where previously Apache
  was controlled by doing a ^C to stop it running).
  
  Reviewed by:	Ken, Lars, Jim, Martin (all concept only)
  
  Revision  Changes    Path
  1.399     +242 -84   apache-1.3/src/main/http_main.c
  
  Index: http_main.c
  ===================================================================
  RCS file: /export/home/cvs/apache-1.3/src/main/http_main.c,v
  retrieving revision 1.398
  retrieving revision 1.399
  diff -u -r1.398 -r1.399
  --- http_main.c	1998/10/06 15:36:02	1.398
  +++ http_main.c	1998/10/06 15:41:44	1.399
  @@ -999,6 +999,10 @@
       fprintf(stderr, "  -l               : list compiled-in modules\n");
       fprintf(stderr, "  -S               : show parsed settings (currently only vhost settings)\n");
       fprintf(stderr, "  -t               : run syntax test for configuration files only\n");
  +#ifdef WIN32
  +    fprintf(stderr, "  -k shutdown      : tell running Apache to shutdown\n");
  +    fprintf(stderr, "  -k restart       : tell running Apache to do a graceful restart\n");
  +#endif
       exit(1);
   }
   
  @@ -2542,17 +2546,41 @@
   
   #ifdef WIN32
   /*
  - * signal_parent() tells the parent process to wake up and do something.
  - * Once woken it will look at shutdown_pending and restart_pending to decide
  - * what to do. If neither variable is set, it will do a shutdown. This function
  - * if called by start_shutdown() or start_restart() in the parent's process
  - * space, so that the variables get set. However it can also be called 
  - * by child processes to force the parent to exit in an emergency.
  + * Signalling Apache on NT.
  + *
  + * Under Unix, Apache can be told to shutdown or restart by sending various
  + * signals (HUP, USR, TERM). On NT we don't have easy access to signals, so
  + * we use "events" instead. The parent apache process goes into a loop
  + * where it waits forever for a set of events. Two of those events are
  + * called
  + *
  + *    apPID_shutdown
  + *    apPID_restart
  + *
  + * (where PID is the PID of the apache parent process). When one of these
  + * is signalled, the Apache parent performs the appropriate action. The events
  + * can become signalled through internal Apache methods (e.g. if the child
  + * finds a fatal error and needs to kill its parent), via the service
  + * control manager (the control thread will signal the shutdown event when
  + * requested to stop the Apache service), from the -k Apache command line,
  + * or from any external program which finds the Apache PID from the
  + * httpd.pid file.
  + *
  + * The signal_parent() function, below, is used to signal one of these events.
  + * It can be called by any child or parent process, since it does not
  + * rely on global variables.
  + *
  + * On entry, type gives the event to signal. 0 means shutdown, 1 means 
  + * graceful restart.
    */
   
  -static void signal_parent(void)
  +static void signal_parent(int type)
   {
       HANDLE e;
  +    char *signal_name;
  +    extern char signal_shutdown_name[];
  +    extern char signal_restart_name[];
  +
       /* after updating the shutdown_pending or restart flags, we need
        * to wake up the parent process so it can see the changes. The
        * parent will normally be waiting for either a child process
  @@ -2564,21 +2592,28 @@
   	return;
       }
   
  -    APD1("*** SIGNAL_PARENT SET ***");
  +    switch(type) {
  +    case 0: signal_name = signal_shutdown_name; break;
  +    case 1: signal_name = signal_restart_name; break;
  +    default: return;
  +    }
   
  -    e = OpenEvent(EVENT_ALL_ACCESS, FALSE, "apache-signal");
  +    APD2("signal_parent signalling event \"%s\"", signal_name);
  +
  +    e = OpenEvent(EVENT_ALL_ACCESS, FALSE, signal_name);
       if (!e) {
  -	/* Um, problem, can't signal the main loop, which means we can't
  +	/* Um, problem, can't signal the parent, which means we can't
   	 * signal ourselves to die. Ignore for now...
   	 */
   	ap_log_error(APLOG_MARK, APLOG_EMERG|APLOG_WIN32ERROR, server_conf,
  -	    "OpenEvent on apache-signal event");
  +	    "OpenEvent on %s event", signal_name);
   	return;
       }
       if (SetEvent(e) == 0) {
   	/* Same problem as above */
   	ap_log_error(APLOG_MARK, APLOG_EMERG|APLOG_WIN32ERROR, server_conf,
  -	    "SetEvent on apache-signal event");
  +	    "SetEvent on %s event", signal_name);
  +	CloseHandle(e);
   	return;
       }
       CloseHandle(e);
  @@ -2586,24 +2621,19 @@
   #endif
   
   /*
  - * start_shutdown() and start_restart(), below, are a first stab at
  + * ap_start_shutdown() and ap_start_restart(), below, are a first stab at
    * functions to initiate shutdown or restart without relying on signals. 
    * Previously this was initiated in sig_term() and restart() signal handlers, 
    * but we want to be able to start a shutdown/restart from other sources --
    * e.g. on Win32, from the service manager. Now the service manager can
  - * call start_shutdown() or start_restart() as appropiate. 
  - *
  - * These should only be called from the parent process itself, since the
  - * parent process will use the shutdown_pending and restart_pending variables
  - * to determine whether to shutdown or restart. The child process should
  - * call signal_parent() directly to tell the parent to die -- this will
  - * cause neither of those variable to be set, which the parent will
  - * assume means something serious is wrong (which it will be, for the
  - * child to force an exit) and so do an exit anyway.
  + * call ap_start_shutdown() or ap_start_restart() as appropiate.  Note that
  + * these functions can also be called by the child processes, since global
  + * variables are no longer used to pass on the required action to the parent.
    */
   
   void ap_start_shutdown(void)
   {
  +#ifndef WIN32
       if (shutdown_pending == 1) {
   	/* Um, is this _probably_ not an error, if the user has
   	 * tried to do a shutdown twice quickly, so we won't
  @@ -2612,24 +2642,23 @@
   	return;
       }
       shutdown_pending = 1;
  -
  -#ifdef WIN32
  -    signal_parent();	    /* get the parent process to wake up */
  +#else
  +    signal_parent(0);	    /* get the parent process to wake up */
   #endif
   }
   
   /* do a graceful restart if graceful == 1 */
   void ap_start_restart(int graceful)
   {
  +#ifndef WIN32
       if (restart_pending == 1) {
   	/* Probably not an error - don't bother reporting it */
   	return;
       }
       restart_pending = 1;
       is_graceful = graceful;
  -
  -#ifdef WIN32
  -    signal_parent();	    /* get the parent process to wake up */
  +#else
  +    signal_parent(1);	    /* get the parent process to wake up */
   #endif /* WIN32 */
   }
   
  @@ -4633,11 +4662,13 @@
    *
    * Signalling between the parent and working process uses a Win32
    * event. Each child has a unique name for the event, which is
  - * passed to it with the -c argument when the child is spawned. The
  + * passed to it with the -Z argument when the child is spawned. The
    * parent sets (signals) this event to tell the child to die.
    * At present all children do a graceful die - they finish all
    * current jobs _and_ empty the listen queue before they exit.
  - * A non-graceful die would need a second event.
  + * A non-graceful die would need a second event. The -Z argument in
  + * the child is also used to create the shutdown and restart events,
  + * since the prefix (apPID) contains the parent process PID.
    *
    * The code below starts with functions at the lowest level -
    * worker threads, and works up to the top level - the main()
  @@ -5001,17 +5032,37 @@
   event *exit_event;
   mutex *start_mutex;
   
  +#define MAX_SIGNAL_NAME 30  /* Long enough for apPID_shutdown, where PID is an int */
  +char signal_name_prefix[MAX_SIGNAL_NAME];
  +char signal_restart_name[MAX_SIGNAL_NAME]; 
  +char signal_shutdown_name[MAX_SIGNAL_NAME];
  +
   #define MAX_SELECT_ERRORS 100
   
  +/*
  + * Initialise the signal names, in the global variables signal_name_prefix, 
  + * signal_restart_name and signal_shutdown_name.
  + */
  +
  +void setup_signal_names(char *prefix)
  +{
  +    ap_snprintf(signal_name_prefix, sizeof(signal_name_prefix), prefix);    
  +    ap_snprintf(signal_shutdown_name, sizeof(signal_shutdown_name), 
  +	"%s_shutdown", signal_name_prefix);    
  +    ap_snprintf(signal_restart_name, sizeof(signal_restart_name), 
  +	"%s_restart", signal_name_prefix);    
  +
  +    APD2("signal prefix %s", signal_name_prefix);
  +}
  +
  +/*
  + * worker_main() is main loop for the child process. The loop in
  + * this function becomes the controlling thread for the actually working
  + * threads (which run in a loop in child_sub_main()).
  + */
  +
   void worker_main(void)
   {
  -    /*
  -     * I am writing this stuff specifically for NT.
  -     * have pulled out a lot of the restart and
  -     * graceful restart stuff, because that is only
  -     * useful on Unix (not sure it even makes sense
  -     * in a multi-threaded env.
  -     */
       int nthreads;
       fd_set main_fds;
       int srv;
  @@ -5059,7 +5110,13 @@
   
       reinit_scoreboard(pconf);
   
  -    //ap_acquire_mutex(start_mutex);
  +    /*
  +     * Wait until we have permission to start accepting connections.
  +     * start_mutex is used to ensure that only one child ever
  +     * goes into the listen/accept loop at once. Also wait on exit_event,
  +     * in case we (this child) is told to die before we get a chance to
  +     * serve any requests.
  +     */
       hObjects[0] = (HANDLE)start_mutex;
       hObjects[1] = (HANDLE)exit_event;
       rv = WaitForMultipleObjects(2, hObjects, FALSE, INFINITE);
  @@ -5085,7 +5142,7 @@
   	ap_log_error(APLOG_MARK, APLOG_CRIT|APLOG_NOERRNO, NULL,
   		    "No sockets were created for listening");
   
  -	signal_parent();	/* tell parent to die */
  +	signal_parent(0);	/* tell parent to die */
   
   	ap_destroy_pool(pchild);
   	cleanup_scoreboard();
  @@ -5114,16 +5171,12 @@
   
       /* spawn off the threads */
       child_handles = (thread *) alloca(nthreads * sizeof(int));
  -    {
  -	int i;
  -
  -	for (i = 0; i < nthreads; i++) {
  -	    child_handles[i] = create_thread((void (*)(void *)) child_main, (void *) i);
  -	}
  -	if (nthreads > max_daemons_limit) {
  -	    max_daemons_limit = nthreads;
  -	}
  +    for (i = 0; i < nthreads; i++) {
  +	child_handles[i] = create_thread((void (*)(void *)) child_main, (void *) i);
       }
  +    if (nthreads > max_daemons_limit) {
  +	max_daemons_limit = nthreads;
  +    }
   
       while (1) {
   #if SEVERELY_VERBOSE
  @@ -5288,22 +5341,21 @@
       clean_parent_exit(0);
   }				/* standalone_main */
   
  -/* Spawn a child Apache process. The child process has the command
  - * line arguments from argc and argv[], plus a -Z argument giving the
  - * name of an event. The child should open and poll or wait on this
  - * event. When it is signalled, the child should die.  prefix is a
  - * prefix string for the event name.
  +/*
  + * Spawn a child Apache process. The child process has the command line arguments from
  + * argc and argv[], plus a -Z argument giving the name of an event. The child should
  + * open and poll or wait on this event. When it is signalled, the child should die.
  + * prefix is a prefix string for the event name.
    * 
  - * The child_num argument on entry contains a serial number for this
  - * child (used to create a unique event name). On exit, this number
  - * will have been incremented by one, ready for the next call.
  + * The child_num argument on entry contains a serial number for this child (used to create
  + * a unique event name). On exit, this number will have been incremented by one, ready
  + * for the next call. 
    *
    * On exit, the value pointed to be *ev will contain the event created
    * to signal the new child process.
    *
  - * The return value is the handle to the child process if successful,
  - * else -1. If -1 is returned the error will already have been logged
  - * by ap_log_error(). 
  + * The return value is the handle to the child process if successful, else -1. If -1 is
  + * returned the error will already have been logged by ap_log_error().
    */
   
   int create_event_and_spawn(int argc, char **argv, event **ev, int *child_num, char *prefix)
  @@ -5311,8 +5363,15 @@
       char buf[40], mod[200];
       int i, rv;
       char **pass_argv = (char **) alloca(sizeof(char *) * (argc + 3));
  -
  -    ap_snprintf(buf, sizeof(buf), "%s_%d", prefix, ++(*child_num));
  +    
  +    /* We need an event to tell the child process to kill itself when
  +     * the parent is doing a shutdown/restart. This will be named
  +     * apPID_CN where PID is the parent Apache process PID and 
  +     * N is a unique child serial number. prefix contains
  +     * the "apPID" part. The child will get the name of this
  +     * event as its -Z command line argument.
  +     */
  +    ap_snprintf(buf, sizeof(buf), "%s_C%d", prefix, ++(*child_num));
       _flushall();
       *ev = CreateEvent(NULL, TRUE, FALSE, buf);
       if (!*ev) {
  @@ -5409,10 +5468,11 @@
       int *child;
       int child_num = 0;
       int rv, cld;
  -    char buf[100];
  +    char signal_prefix_string[100];
       int i;
       time_t tmstart;
  -    HANDLE signal_event;	/* used to signal shutdown/restart to parent */
  +    HANDLE signal_shutdown_event;	/* used to signal shutdown to parent */
  +    HANDLE signal_restart_event;	/* used to signal a restart to parent */
       HANDLE process_handles[MAX_PROCESSES];
       HANDLE process_kill_events[MAX_PROCESSES];
       int current_live_processes = 0; /* number of child process we know about */
  @@ -5425,22 +5485,34 @@
       is_graceful = 0;
       ++generation;
   
  -    signal_event = OpenEvent(EVENT_ALL_ACCESS, FALSE, "apache-signal");
  -    if (!signal_event) {
  +    ap_snprintf(signal_prefix_string, sizeof(signal_prefix_string),
  +	        "ap%d", getpid());
  +    setup_signal_names(signal_prefix_string);
  +
  +    signal_shutdown_event = CreateEvent(NULL, TRUE, FALSE, signal_shutdown_name);
  +    if (!signal_shutdown_event) {
  +	ap_log_error(APLOG_MARK, APLOG_EMERG|APLOG_WIN32ERROR, server_conf,
  +		    "Cannot create shutdown event %s", signal_shutdown_name);
  +	exit(1);
  +    }
  +    APD2("master_main: created event %s", signal_shutdown_name);
  +    signal_restart_event = CreateEvent(NULL, TRUE, FALSE, signal_restart_name);
  +    if (!signal_restart_event) {
  +	CloseHandle(signal_shutdown_event);
   	ap_log_error(APLOG_MARK, APLOG_EMERG|APLOG_WIN32ERROR, server_conf,
  -		    "Cannot open apache-signal event");
  +		    "Cannot create restart event %s", signal_restart_name);
   	exit(1);
       }
  +    APD2("master_main: created event %s", signal_restart_name);
   
  -    sprintf(buf, "Apache%d", getpid());
  -    start_mutex = ap_create_mutex(buf);
  +    start_mutex = ap_create_mutex(signal_prefix_string);
       ev = (event **) alloca(sizeof(event *) * nchild);
       child = (int *) alloca(sizeof(int) * (nchild+1));
   
       while (processes_to_create--) {
   	service_set_status(SERVICE_START_PENDING);
   	if (create_process(process_handles, process_kill_events, 
  -	    &current_live_processes, &child_num, buf, argc, argv) < 0) {
  +	    &current_live_processes, &child_num, signal_prefix_string, argc, argv) <
0) {
   	    goto die_now;
   	}
       }
  @@ -5461,8 +5533,6 @@
   	ap_set_version();
   	ap_init_modules(pconf, server_conf);
   	version_locked++;
  -	if (!is_graceful)
  -	    reinit_scoreboard(pconf);
   
   	restart_pending = shutdown_pending = 0;
   
  @@ -5478,15 +5548,17 @@
   		ap_log_error(APLOG_MARK,APLOG_ERR|APLOG_NOERRNO, server_conf,
    			"master_main: no child processes alive! creating one");
   		if (create_process(process_handles, process_kill_events, 
  -		    &current_live_processes, &child_num, buf, argc, argv) < 0) {
  +		    &current_live_processes, &child_num, signal_prefix_string, 
  +		    argc, argv) < 0) {
   		    goto die_now;
   		}
   		if (processes_to_create) {
   		    processes_to_create--;
   		}
   	    }
  -	    process_handles[current_live_processes] = signal_event;
  -	    rv = WaitForMultipleObjects(current_live_processes+1, (HANDLE *)process_handles, 
  +	    process_handles[current_live_processes] = signal_shutdown_event;
  +	    process_handles[current_live_processes+1] = signal_restart_event;
  +	    rv = WaitForMultipleObjects(current_live_processes+2, (HANDLE *)process_handles, 
   			FALSE, INFINITE);
   	    if (rv == WAIT_FAILED) {
   		/* Something serious is wrong */
  @@ -5494,14 +5566,36 @@
   		    "WaitForMultipeObjects on process handles and apache-signal -- doing shutdown");
   		shutdown_pending = 1;
   		break;
  +	    }
  +	    if (rv == WAIT_TIMEOUT) {
  +		/* Hey, this cannot happen */
  +		ap_log_error(APLOG_MARK, APLOG_ERR, server_conf,
  +		    "WaitForMultipeObjects with INFINITE wait exited with WAIT_TIMEOUT");
  +		shutdown_pending = 1;
   	    }
  -	    ap_assert(rv != WAIT_TIMEOUT);
  +
   	    cld = rv - WAIT_OBJECT_0;
   	    APD4("main process: wait finished, cld=%d handle %d (max=%d)", cld, process_handles[cld],
current_live_processes);
   	    if (cld == current_live_processes) {
  -		/* stop_event is signalled, we should exit now */
  -		if (ResetEvent(signal_event) == 0)
  -		    APD1("main process: *** ERROR: ResetEvent(stop_event) failed ***");
  +		/* shutdown event signalled, we should exit now */
  +		if (ResetEvent(signal_shutdown_event) == 0) {
  +		    ap_log_error(APLOG_MARK, APLOG_ERR|APLOG_WIN32ERROR, server_conf,
  +			"ResetEvent(signal_shutdown_event)");
  +		    /* Continue -- since we are doing a shutdown anyway */
  +		}
  +		shutdown_pending = 1;
  +		APD3("main process: stop_event signalled: shutdown_pending=%d, restart_pending=%d",
  +		    shutdown_pending, restart_pending);
  +		break;
  +	    }
  +	    if (cld == current_live_processes+1) {
  +		/* restart event signalled, we should exit now */
  +		if (ResetEvent(signal_restart_event) == 0) {
  +		    ap_log_error(APLOG_MARK, APLOG_ERR|APLOG_WIN32ERROR, server_conf,
  +			"ResetEvent(signal_restart_event)");
  +		    /* Continue -- hopefully the restart will fix the problem */
  +		}
  +		restart_pending = 1;
   		APD3("main process: stop_event signalled: shutdown_pending=%d, restart_pending=%d",
   		    shutdown_pending, restart_pending);
   		break;
  @@ -5510,7 +5604,8 @@
   	    cleanup_process(process_handles, process_kill_events, cld, &current_live_processes);
   	    APD2("main_process: child in slot %d died", rv);
   	    if (processes_to_create) {
  -		create_process(process_handles, process_kill_events, &current_live_processes, &child_num,
buf, argc, argv);
  +		create_process(process_handles, process_kill_events, &current_live_processes, 
  +			&child_num, signal_prefix_string, argc, argv);
   		processes_to_create--;
   	    }
   	}
  @@ -5527,7 +5622,6 @@
   		    ap_log_error(APLOG_MARK,APLOG_WIN32ERROR, server_conf,
   			"SetEvent for child process in slot #%d", i);
   	    }
  -
   	    break;
   	}
   	if (restart_pending) {
  @@ -5539,7 +5633,8 @@
   	    for (i = 0; i < nchild; ++i) {
   		if (current_live_processes >= MAX_PROCESSES)
   		    break;
  -		create_process(process_handles, process_kill_events, &current_live_processes, &child_num,
buf, argc, argv);
  +		create_process(process_handles, process_kill_events, &current_live_processes, 
  +		    &child_num, signal_prefix_string, argc, argv);
   		processes_to_create--;
   	    }
   	    for (i = 0; i < children_to_kill; i++) {
  @@ -5559,7 +5654,8 @@
       APD2("*** main process shutdown, processes=%d ***", current_live_processes);
   
   die_now:
  -    CloseHandle(signal_event);
  +    CloseHandle(signal_restart_event);
  +    CloseHandle(signal_shutdown_event);
   
       tmstart = time(NULL);
       while (current_live_processes && ((tmstart+60) > time(NULL))) {
  @@ -5596,10 +5692,61 @@
       }
   
       ap_destroy_mutex(start_mutex);
  +
       service_set_status(SERVICE_STOPPED);
       return (0);
   }
   
  +/*
  + * Send signal to a running Apache. On entry signal should contain
  + * either "shutdown" or "restart"
  + */
  +
  +void send_signal(pool *p, char *signal)
  +{
  +    char prefix[20];
  +    FILE *fp;
  +    int nread;
  +    char *fname;
  +    int end;
  +
  +    fname = ap_server_root_relative (p, ap_pid_fname);
  +
  +    fp = fopen(fname, "r");
  +    if (!fp) {
  +	printf("Cannot read apache PID file %s\n", fname);
  +	return;
  +    }
  +    prefix[0] = 'a';
  +    prefix[1] = 'p';
  +
  +    nread = fread(prefix+2, 1, sizeof(prefix)-3, fp);
  +    if (nread == 0) {
  +	fclose(fp);
  +	printf("PID file %s was empty\n", fname);
  +	return;
  +    }
  +    fclose(fp);
  +
  +    /* Terminate the prefix string */
  +    end = 2 + nread - 1;
  +    while (end > 0 && (prefix[end] == '\r' || prefix[end] == '\n'))
  +	end--;
  +    prefix[end + 1] = '\0';
  +
  +    setup_signal_names(prefix);
  +
  +    if (!strcasecmp(signal, "shutdown"))
  +	ap_start_shutdown();
  +    else if (!strcasecmp(signal, "restart"))
  +	ap_start_restart(1);
  +    else
  +	printf("Unknown signal name \"%s\". Use either shutdown or restart.\n",
  +	    signal);
  +
  +    return;
  +}
  +
   #ifdef WIN32
   __declspec(dllexport)
        int apache_main(int argc, char *argv[])
  @@ -5613,6 +5760,7 @@
       int run_as_service = 1;
       int install = 0;
       int configtestonly = 0;
  +    char *signal_to_send = NULL;
       
       common_init();
   
  @@ -5637,7 +5785,7 @@
   
       ap_setup_prelinked_modules();
   
  -    while ((c = getopt(argc, argv, "D:C:c:Xd:f:vVhlZ:iusSt")) != -1) {
  +    while ((c = getopt(argc, argv, "D:C:c:Xd:f:vVhlZ:iusStk:")) != -1) {
           char **new;
   	switch (c) {
   	case 'c':
  @@ -5659,7 +5807,9 @@
   	    cp = strchr(optarg, '_');
   	    ap_assert(cp);
   	    *cp = 0;
  -	    start_mutex = ap_open_mutex(optarg);
  +	    setup_signal_names(optarg);
  +	    start_mutex = ap_open_mutex(signal_name_prefix);
  +	    ap_assert(start_mutex);
   	    child = 1;
   	    break;
   	case 'i':
  @@ -5674,6 +5824,9 @@
   	case 'S':
   	    ap_dump_settings = 1;
   	    break;
  +	case 'k':
  +	    signal_to_send = optarg;
  +	    break;
   #endif /* WIN32 */
   	case 'd':
   	    ap_cpystrn(ap_server_root, ap_os_canonical_filename(pconf, optarg), sizeof(ap_server_root));
  @@ -5716,6 +5869,11 @@
       if (configtestonly) {
           fprintf(stderr, "Syntax OK\n");
           exit(0);
  +    }
  +
  +    if (signal_to_send) {
  +	send_signal(pconf, signal_to_send);
  +	exit(0);
       }
   
       if (!child && !ap_dump_settings && !install) {
  
  
  

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