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 "../tdb/include/tdb.h"
  29 #include "lib/socket/socket.h"
  30 #include "smbd/process_model.h"
  31 #include "param/secrets.h"
  32 #include "system/filesys.h"
  33 #include "cluster/cluster.h"
  34 #include "param/param.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         /* tdb needs special fork handling */
  60         if (tdb_reopen_all(1) == -1) {
  61                 DEBUG(0,("prefork_reload_after_fork: tdb_reopen_all failed.\n"));
  62         }
  63
  64         /* Ensure that the forked children do not expose identical random streams */
  65         set_need_random_reseed();
  66 }
  67
  68 /*
  69   called when a listening socket becomes readable.
  70 */
  71 static void prefork_accept_connection(struct tevent_context *ev,
  72                                       struct loadparm_context *lp_ctx,
  73                                       struct socket_context *listen_socket,
  74                                        void (*new_conn)(struct tevent_context *,
  75                                                         struct loadparm_context *, struct socket_context *,
  76                                                         struct server_id , void *),
  77                                        void *private_data)
  78 {
  79         NTSTATUS status;
  80         struct socket_context *connected_socket;
  81         pid_t pid = getpid();
  82
  83         /* accept an incoming connection. */
  84         status = socket_accept(listen_socket, &connected_socket);
  85         if (!NT_STATUS_IS_OK(status)) {
  86                 return;
  87         }
  88
  89         talloc_steal(private_data, connected_socket);
  90
  91         new_conn(ev, lp_ctx, connected_socket, cluster_id(pid, socket_get_fd(connected_socket)), private_data);
  92 }
  93
  94 /*
  95   called to create a new server task
  96 */
  97 static void prefork_new_task(struct tevent_context *ev,
  98                              struct loadparm_context *lp_ctx,
  99                              const char *service_name,
 100                              void (*new_task_fn)(struct tevent_context *, struct loadparm_context *lp_ctx, struct server_id , void *),
 101                              void *private_data)
 102 {
 103         pid_t pid;
 104         int i, num_children;
 105
 106         struct tevent_context *ev2, *ev_parent;
 107
 108         pid = fork();
 109
 110         if (pid != 0) {
 111                 /* parent or error code ... go back to the event loop */
 112                 return;
 113         }
 114
 115         pid = getpid();
 116
 117         /* This is now the child code. We need a completely new event_context to work with */
 118         ev2 = s4_event_context_init(NULL);
 119
 120         /* the service has given us a private pointer that
 121            encapsulates the context it needs for this new connection -
 122            everything else will be freed */
 123         talloc_steal(ev2, private_data);
 124
 125         /* this will free all the listening sockets and all state that
 126            is not associated with this new connection */
 127         talloc_free(ev);
 128
 129         setproctitle("task %s server_id[%d]", service_name, pid);
 130
 131         prefork_reload_after_fork();
 132
 133         /* setup this new connection: process will bind to it's sockets etc */
 134         new_task_fn(ev2, lp_ctx, cluster_id(pid, 0), private_data);
 135
 136         num_children = lp_parm_int(lp_ctx, NULL, "prefork children", service_name, 0);
 137         if (num_children == 0) {
 138
 139                 /* We don't want any kids hanging around for this one,
 140                  * let the parent do all the work */
 141                 event_loop_wait(ev2);
 142
 143                 talloc_free(ev2);
 144                 exit(0);
 145         }
 146
 147         /* We are now free to spawn some child proccesses */
 148
 149         for (i=0; i < num_children; i++) {
 150
 151                 pid = fork();
 152                 if (pid > 0) {
 153                         continue;
 154                 } else if (pid == -1) {
 155                         return;
 156                 } else {
 157                         pid = getpid();
 158                         setproctitle("task %s server_id[%d]", service_name, pid);
 159
 160                         prefork_reload_after_fork();
 161
 162                         /* we can't return to the top level here, as that event context is gone,
 163                            so we now process events in the new event context until there are no
 164                            more to process */
 165                         event_loop_wait(ev2);
 166
 167                         talloc_free(ev2);
 168                         exit(0);
 169                 }
 170         }
 171
 172         /* Don't listen on the sockets we just gave to the children */
 173         talloc_free(ev2);
 174
 175         /* But we need a events system to handle reaping children */
 176         ev_parent = s4_event_context_init(NULL);
 177
 178         /* TODO: Handle some events... */
 179
 180         /* we can't return to the top level here, as that event context is gone,
 181            so we now process events in the new event context until there are no
 182            more to process */
 183         event_loop_wait(ev_parent);
 184
 185         talloc_free(ev_parent);
 186         exit(0);
 187
 188 }
 189
 190
 191 /* called when a task goes down */
 192 _NORETURN_ static void prefork_terminate(struct tevent_context *ev, struct loadparm_context *lp_ctx, const char *reason)
 193 {
 194         DEBUG(2,("prefork_terminate: reason[%s]\n",reason));
 195 }
 196
 197 /* called to set a title of a task or connection */
 198 static void prefork_set_title(struct tevent_context *ev, const char *title)
 199 {
 200         if (title) {
 201                 setproctitle("%s", title);
 202         } else {
 203                 setproctitle(NULL);
 204         }
 205 }
 206
 207 static const struct model_ops prefork_ops = {
 208         .name                   = "prefork",
 209         .model_init             = prefork_model_init,
 210         .accept_connection      = prefork_accept_connection,
 211         .new_task               = prefork_new_task,
 212         .terminate              = prefork_terminate,
 213         .set_title              = prefork_set_title,
 214 };
 215
 216 /*
 217   initialise the prefork process model, registering ourselves with the process model subsystem
 218  */
 219 NTSTATUS process_model_prefork_init(void)
 220 {
 221         return register_process_model(&prefork_ops);
 222 }