source4/smbd/process_prefork.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    process model: prefork (n client connections per process)
   5
   6    Copyright (C) Andrew Tridgell 1992-2005
   7    Copyright (C) James J Myers 2003 <myersjj@samba.org>
   8    Copyright (C) Stefan (metze) Metzmacher 2004
   9    Copyright (C) Andrew Bartlett 2008 <abartlet@samba.org>
  10    Copyright (C) David Disseldorp 2008 <ddiss@sgi.com>
  11
  12    This program is free software; you can redistribute it and/or modify
  13    it under the terms of the GNU General Public License as published by
  14    the Free Software Foundation; either version 3 of the License, or
  15    (at your option) any later version.
  16
  17    This program is distributed in the hope that it will be useful,
  18    but WITHOUT ANY WARRANTY; without even the implied warranty of
  19    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20    GNU General Public License for more details.
  21
  22    You should have received a copy of the GNU General Public License
  23    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  24 */
  25
  26 #include "includes.h"
  27 #include "lib/events/events.h"
  28 #include "lib/socket/socket.h"
  29 #include "smbd/process_model.h"
  30 #include "param/secrets.h"
  31 #include "system/filesys.h"
  32 #include "cluster/cluster.h"
  33 #include "param/param.h"
  34 #include "lib/ldb_wrap.h"
  35
  36 #ifdef HAVE_SETPROCTITLE
  37 #ifdef HAVE_SETPROCTITLE_H
  38 #include <setproctitle.h>
  39 #endif
  40 #else
  41 #define setproctitle none_setproctitle
  42 static int none_setproctitle(const char *fmt, ...) PRINTF_ATTRIBUTE(1, 2);
  43 static int none_setproctitle(const char *fmt, ...)
  44 {
  45         return 0;
  46 }
  47 #endif
  48
  49 /*
  50   called when the process model is selected
  51 */
  52 static void prefork_model_init(struct tevent_context *ev)
  53 {
  54         signal(SIGCHLD, SIG_IGN);
  55 }
  56
  57 static void prefork_reload_after_fork(void)
  58 {
  59         ldb_wrap_fork_hook();
  60
  61         /* Ensure that the forked children do not expose identical random streams */
  62         set_need_random_reseed();
  63 }
  64
  65 /*
  66   called when a listening socket becomes readable.
  67 */
  68 static void prefork_accept_connection(struct tevent_context *ev,
  69                                       struct loadparm_context *lp_ctx,
  70                                       struct socket_context *listen_socket,
  71                                        void (*new_conn)(struct tevent_context *,
  72                                                         struct loadparm_context *, struct socket_context *,
  73                                                         struct server_id , void *),
  74                                        void *private_data)
  75 {
  76         NTSTATUS status;
  77         struct socket_context *connected_socket;
  78         pid_t pid = getpid();
  79
  80         /* accept an incoming connection. */
  81         status = socket_accept(listen_socket, &connected_socket);
  82         if (!NT_STATUS_IS_OK(status)) {
  83                 return;
  84         }
  85
  86         talloc_steal(private_data, connected_socket);
  87
  88         new_conn(ev, lp_ctx, connected_socket, cluster_id(pid, socket_get_fd(connected_socket)), private_data);
  89 }
  90
  91 /*
  92   called to create a new server task
  93 */
  94 static void prefork_new_task(struct tevent_context *ev,
  95                              struct loadparm_context *lp_ctx,
  96                              const char *service_name,
  97                              void (*new_task_fn)(struct tevent_context *, struct loadparm_context *lp_ctx, struct server_id , void *),
  98                              void *private_data)
  99 {
 100         pid_t pid;
 101         int i, num_children;
 102
 103         struct tevent_context *ev2, *ev_parent;
 104
 105         pid = fork();
 106
 107         if (pid != 0) {
 108                 /* parent or error code ... go back to the event loop */
 109                 return;
 110         }
 111
 112         pid = getpid();
 113
 114         /* This is now the child code. We need a completely new event_context to work with */
 115         ev2 = s4_event_context_init(NULL);
 116
 117         /* the service has given us a private pointer that
 118            encapsulates the context it needs for this new connection -
 119            everything else will be freed */
 120         talloc_steal(ev2, private_data);
 121
 122         /* this will free all the listening sockets and all state that
 123            is not associated with this new connection */
 124         talloc_free(ev);
 125
 126         setproctitle("task %s server_id[%d]", service_name, pid);
 127
 128         prefork_reload_after_fork();
 129
 130         /* setup this new connection: process will bind to it's sockets etc */
 131         new_task_fn(ev2, lp_ctx, cluster_id(pid, 0), private_data);
 132
 133         num_children = lp_parm_int(lp_ctx, NULL, "prefork children", service_name, 0);
 134         if (num_children == 0) {
 135
 136                 /* We don't want any kids hanging around for this one,
 137                  * let the parent do all the work */
 138                 event_loop_wait(ev2);
 139
 140                 talloc_free(ev2);
 141                 exit(0);
 142         }
 143
 144         /* We are now free to spawn some child proccesses */
 145
 146         for (i=0; i < num_children; i++) {
 147
 148                 pid = fork();
 149                 if (pid > 0) {
 150                         continue;
 151                 } else if (pid == -1) {
 152                         return;
 153                 } else {
 154                         pid = getpid();
 155                         setproctitle("task %s server_id[%d]", service_name, pid);
 156
 157                         prefork_reload_after_fork();
 158
 159                         /* we can't return to the top level here, as that event context is gone,
 160                            so we now process events in the new event context until there are no
 161                            more to process */
 162                         event_loop_wait(ev2);
 163
 164                         talloc_free(ev2);
 165                         exit(0);
 166                 }
 167         }
 168
 169         /* Don't listen on the sockets we just gave to the children */
 170         talloc_free(ev2);
 171
 172         /* But we need a events system to handle reaping children */
 173         ev_parent = s4_event_context_init(NULL);
 174
 175         /* TODO: Handle some events... */
 176
 177         /* we can't return to the top level here, as that event context is gone,
 178            so we now process events in the new event context until there are no
 179            more to process */
 180         event_loop_wait(ev_parent);
 181
 182         talloc_free(ev_parent);
 183         exit(0);
 184
 185 }
 186
 187
 188 /* called when a task goes down */
 189 _NORETURN_ static void prefork_terminate(struct tevent_context *ev, struct loadparm_context *lp_ctx, const char *reason)
 190 {
 191         DEBUG(2,("prefork_terminate: reason[%s]\n",reason));
 192 }
 193
 194 /* called to set a title of a task or connection */
 195 static void prefork_set_title(struct tevent_context *ev, const char *title)
 196 {
 197         if (title) {
 198                 setproctitle("%s", title);
 199         } else {
 200                 setproctitle(NULL);
 201         }
 202 }
 203
 204 static const struct model_ops prefork_ops = {
 205         .name                   = "prefork",
 206         .model_init             = prefork_model_init,
 207         .accept_connection      = prefork_accept_connection,
 208         .new_task               = prefork_new_task,
 209         .terminate              = prefork_terminate,
 210         .set_title              = prefork_set_title,
 211 };
 212
 213 /*
 214   initialise the prefork process model, registering ourselves with the process model subsystem
 215  */
 216 NTSTATUS process_model_prefork_init(void)
 217 {
 218         return register_process_model(&prefork_ops);
 219 }