source4 smbd prefork: Add backoff to process restart
[gd/samba-autobuild/.git] / source4 / smbd / process_prefork.c
index d2627937b44f56fbf27ee7a251b03a1027ca14c9..a023290677728a5e88d2db275ef768b61315dc62 100644 (file)
@@ -35,6 +35,8 @@
 #include "ldb_wrap.h"
 #include "lib/util/tfork.h"
 
+#define min(a, b) (((a) < (b)) ? (a) : (b))
+
 NTSTATUS process_model_prefork_init(void);
 static void prefork_new_task(
     struct tevent_context *ev,
@@ -51,17 +53,23 @@ static void prefork_new_task(
 static void prefork_fork_worker(struct task_server *task,
                                struct tevent_context *ev,
                                struct tevent_context *ev2,
+                               struct loadparm_context *lp_ctx,
                                const struct service_details *service_details,
                                const char *service_name,
                                int control_pipe[2],
+                               unsigned restart_delay,
                                struct process_details *pd);
+static void prefork_child_pipe_handler(struct tevent_context *ev,
+                                      struct tevent_fd *fde,
+                                      uint16_t flags,
+                                      void *private_data);
+static void setup_handlers(struct tevent_context *ev, int from_parent_fd);
 
 /*
  * State needed to restart the master process or a worker process if they
  * terminate early.
  */
 struct master_restart_context {
-       struct loadparm_context *lp_ctx;
        struct task_server *(*new_task_fn)(struct tevent_context *,
                                           struct loadparm_context *lp_ctx,
                                           struct server_id,
@@ -78,10 +86,12 @@ struct worker_restart_context {
 };
 
 struct restart_context {
+       struct loadparm_context *lp_ctx;
        struct tfork *t;
        int from_parent_fd;
        const struct service_details *service_details;
        const char *service_name;
+       unsigned restart_delay;
        struct master_restart_context *master;
        struct worker_restart_context *worker;
 };
@@ -147,18 +157,213 @@ static void prefork_pipe_handler(struct tevent_context *event_ctx,
        exit(0);
 }
 
+
+/*
+ * called to create a new server task
+ */
+static void prefork_fork_master(
+    struct tevent_context *ev,
+    struct loadparm_context *lp_ctx,
+    const char *service_name,
+    struct task_server *(*new_task_fn)(struct tevent_context *,
+                                      struct loadparm_context *lp_ctx,
+                                      struct server_id,
+                                      void *,
+                                      void *),
+    void *private_data,
+    const struct service_details *service_details,
+    unsigned restart_delay,
+    int from_parent_fd)
+{
+       pid_t pid;
+       struct tfork* t = NULL;
+       int i, num_children;
+
+       struct tevent_context *ev2;
+       struct task_server *task = NULL;
+       struct process_details pd = initial_process_details;
+       int control_pipe[2];
+
+       t = tfork_create();
+       if (t == NULL) {
+               smb_panic("failure in tfork\n");
+       }
+
+       DBG_NOTICE("Forking [%s] pre-fork master process\n", service_name);
+       pid = tfork_child_pid(t);
+       if (pid != 0) {
+               struct tevent_fd *fde = NULL;
+               int fd = tfork_event_fd(t);
+               struct restart_context *rc = NULL;
+
+               /* Register a pipe handler that gets called when the prefork
+                * master process terminates.
+                */
+               rc = talloc_zero(ev, struct restart_context);
+               if (rc == NULL) {
+                       smb_panic("OOM allocating restart context\n");
+               }
+               rc->t = t;
+               rc->lp_ctx = lp_ctx;
+               rc->service_name = service_name;
+               rc->service_details = service_details;
+               rc->from_parent_fd = from_parent_fd;
+               rc->restart_delay = restart_delay;
+               rc->master = talloc_zero(rc, struct master_restart_context);
+               if (rc->master == NULL) {
+                       smb_panic("OOM allocating master restart context\n");
+               }
+
+               rc->master->new_task_fn = new_task_fn;
+               rc->master->private_data = private_data;
+
+               fde = tevent_add_fd(
+                   ev, ev, fd, TEVENT_FD_READ, prefork_child_pipe_handler, rc);
+               if (fde == NULL) {
+                       smb_panic("Failed to add child pipe handler, "
+                                 "after fork");
+               }
+               tevent_fd_set_auto_close(fde);
+               return;
+       }
+
+       pid = getpid();
+       setproctitle("task[%s] pre-fork master", service_name);
+
+       /*
+        * this will free all the listening sockets and all state that
+        * is not associated with this new connection
+        */
+       if (tevent_re_initialise(ev) != 0) {
+               smb_panic("Failed to re-initialise tevent after fork");
+       }
+       prefork_reload_after_fork();
+       setup_handlers(ev, from_parent_fd);
+
+       if (service_details->inhibit_pre_fork) {
+               task = new_task_fn(
+                   ev, lp_ctx, cluster_id(pid, 0), private_data, NULL);
+               /*
+                * The task does not support pre-fork
+                */
+               if (task != NULL && service_details->post_fork != NULL) {
+                       service_details->post_fork(task, &pd);
+               }
+               tevent_loop_wait(ev);
+               TALLOC_FREE(ev);
+               exit(0);
+       }
+
+       /*
+        * This is now the child code. We need a completely new event_context
+        * to work with
+        */
+       ev2 = s4_event_context_init(NULL);
+
+       /* setup this new connection: process will bind to it's sockets etc
+        *
+        * While we can use ev for the child, which has been re-initialised
+        * above we must run the new task under ev2 otherwise the children would
+        * be listening on the sockets.  Also we don't want the top level
+        * process accepting and handling requests, it's responsible for
+        * monitoring and controlling the child work processes.
+        */
+       task = new_task_fn(ev2, lp_ctx, cluster_id(pid, 0), private_data, NULL);
+       if (task == NULL) {
+               TALLOC_FREE(ev);
+               TALLOC_FREE(ev2);
+               exit(0);
+       }
+
+       {
+               int default_children;
+               default_children = lpcfg_prefork_children(lp_ctx);
+               num_children = lpcfg_parm_int(lp_ctx, NULL, "prefork children",
+                                             service_name, default_children);
+       }
+       if (num_children == 0) {
+               DBG_WARNING("Number of pre-fork children for %s is zero, "
+                           "NO worker processes will be started for %s\n",
+                           service_name, service_name);
+       }
+       DBG_NOTICE("Forking %d %s worker processes\n",
+                  num_children, service_name);
+       {
+               int ret;
+               ret = pipe(control_pipe);
+               if (ret != 0) {
+                       smb_panic("Unable to create worker control pipe\n");
+               }
+               smb_set_close_on_exec(control_pipe[0]);
+               smb_set_close_on_exec(control_pipe[1]);
+       }
+
+       /*
+        * We are now free to spawn some worker processes
+        */
+       for (i=0; i < num_children; i++) {
+               prefork_fork_worker(task,
+                                   ev,
+                                   ev2,
+                                   lp_ctx,
+                                   service_details,
+                                   service_name,
+                                   control_pipe,
+                                   0,
+                                   &pd);
+               pd.instances++;
+       }
+
+       /* Don't listen on the sockets we just gave to the children */
+       tevent_loop_wait(ev);
+       TALLOC_FREE(ev);
+       /* We need to keep ev2 until we're finished for the messaging to work */
+       TALLOC_FREE(ev2);
+       exit(0);
+
+}
 static void prefork_restart(struct tevent_context *ev,
                            struct restart_context *rc)
 {
+       unsigned max_backoff = 0;
+       unsigned backoff = 0;
+       unsigned restart_delay = rc->restart_delay;
+       unsigned default_value = 0;
+
+       default_value = lpcfg_prefork_backoff_increment(rc->lp_ctx);
+       backoff = lpcfg_parm_int(rc->lp_ctx,
+                                NULL,
+                                "prefork backoff increment",
+                                rc->service_name,
+                                default_value);
+
+       default_value = lpcfg_prefork_maximum_backoff(rc->lp_ctx);
+       max_backoff = lpcfg_parm_int(rc->lp_ctx,
+                                    NULL,
+                                    "prefork maximum backoff",
+                                    rc->service_name,
+                                    default_value);
+
+       if (restart_delay > 0) {
+               DBG_ERR("Restarting [%s] pre-fork %s in (%d) seconds\n",
+                       rc->service_name,
+                       (rc->master == NULL) ? "worker" : "master",
+                       restart_delay);
+               sleep(restart_delay);
+       }
+       restart_delay += backoff;
+       restart_delay = min(restart_delay, max_backoff);
+
        if (rc->master != NULL) {
                DBG_ERR("Restarting [%s] pre-fork master\n", rc->service_name);
-               prefork_new_task(ev,
-                                rc->master->lp_ctx,
-                                rc->service_name,
-                                rc->master->new_task_fn,
-                                rc->master->private_data,
-                                rc->service_details,
-                                rc->from_parent_fd);
+               prefork_fork_master(ev,
+                                   rc->lp_ctx,
+                                   rc->service_name,
+                                   rc->master->new_task_fn,
+                                   rc->master->private_data,
+                                   rc->service_details,
+                                   restart_delay,
+                                   rc->from_parent_fd);
        } else if (rc->worker != NULL) {
                struct process_details pd = initial_process_details;
                DBG_ERR("Restarting [%s] pre-fork worker(%d)\n",
@@ -168,9 +373,11 @@ static void prefork_restart(struct tevent_context *ev,
                prefork_fork_worker(rc->worker->task,
                                    ev,
                                    rc->worker->ev2,
+                                   rc->lp_ctx,
                                    rc->service_details,
                                    rc->service_name,
                                    rc->worker->control_pipe,
+                                   restart_delay,
                                    &pd);
        }
 }
@@ -309,9 +516,11 @@ static void setup_handlers(struct tevent_context *ev, int from_parent_fd) {
 static void prefork_fork_worker(struct task_server *task,
                                struct tevent_context *ev,
                                struct tevent_context *ev2,
+                               struct loadparm_context *lp_ctx,
                                const struct service_details *service_details,
                                const char *service_name,
                                int control_pipe[2],
+                               unsigned restart_delay,
                                struct process_details *pd)
 {
        struct tfork *w = NULL;
@@ -333,8 +542,10 @@ static void prefork_fork_worker(struct task_server *task,
                        smb_panic("OOM allocating restart context\n");
                }
                rc->t = w;
+               rc->lp_ctx = lp_ctx;
                rc->service_name = service_name;
                rc->service_details = service_details;
+               rc->restart_delay = restart_delay;
                rc->master = NULL;
                rc->worker = talloc_zero(rc, struct worker_restart_context);
                if (rc->worker == NULL) {
@@ -388,148 +599,14 @@ static void prefork_new_task(
        const struct service_details *service_details,
        int from_parent_fd)
 {
-       pid_t pid;
-       struct tfork* t = NULL;
-       int i, num_children;
-
-       struct tevent_context *ev2;
-       struct task_server *task = NULL;
-       struct process_details pd = initial_process_details;
-       int control_pipe[2];
-
-       t = tfork_create();
-       if (t == NULL) {
-               smb_panic("failure in tfork\n");
-       }
-
-       DBG_NOTICE("Forking [%s] pre-fork master process\n", service_name);
-       pid = tfork_child_pid(t);
-       if (pid != 0) {
-               struct tevent_fd *fde = NULL;
-               int fd = tfork_event_fd(t);
-               struct restart_context *rc = NULL;
-
-               /* Register a pipe handler that gets called when the prefork
-                * master process terminates.
-                */
-               rc = talloc_zero(ev, struct restart_context);
-               if (rc == NULL) {
-                       smb_panic("OOM allocating restart context\n");
-               }
-               rc->t = t;
-               rc->service_name = service_name;
-               rc->service_details = service_details;
-               rc->from_parent_fd = from_parent_fd;
-               rc->master = talloc_zero(rc, struct master_restart_context);
-               if (rc->master == NULL) {
-                       smb_panic("OOM allocating master restart context\n");
-               }
-
-               rc->master->lp_ctx = lp_ctx;
-               rc->master->new_task_fn = new_task_fn;
-               rc->master->private_data = private_data;
-
-               fde = tevent_add_fd(
-                   ev, ev, fd, TEVENT_FD_READ, prefork_child_pipe_handler, rc);
-               if (fde == NULL) {
-                       smb_panic("Failed to add child pipe handler, "
-                                 "after fork");
-               }
-               tevent_fd_set_auto_close(fde);
-               return;
-       }
-
-       pid = getpid();
-       setproctitle("task[%s] pre-fork master", service_name);
-
-       /*
-        * this will free all the listening sockets and all state that
-        * is not associated with this new connection
-        */
-       if (tevent_re_initialise(ev) != 0) {
-               smb_panic("Failed to re-initialise tevent after fork");
-       }
-       prefork_reload_after_fork();
-       setup_handlers(ev, from_parent_fd);
-
-       if (service_details->inhibit_pre_fork) {
-               task = new_task_fn(
-                   ev, lp_ctx, cluster_id(pid, 0), private_data, NULL);
-               /*
-                * The task does not support pre-fork
-                */
-               if (task != NULL && service_details->post_fork != NULL) {
-                       service_details->post_fork(task, &pd);
-               }
-               tevent_loop_wait(ev);
-               TALLOC_FREE(ev);
-               exit(0);
-       }
-
-       /*
-        * This is now the child code. We need a completely new event_context
-        * to work with
-        */
-       ev2 = s4_event_context_init(NULL);
-
-       /* setup this new connection: process will bind to it's sockets etc
-        *
-        * While we can use ev for the child, which has been re-initialised
-        * above we must run the new task under ev2 otherwise the children would
-        * be listening on the sockets.  Also we don't want the top level
-        * process accepting and handling requests, it's responsible for
-        * monitoring and controlling the child work processes.
-        */
-       task = new_task_fn(ev2, lp_ctx, cluster_id(pid, 0), private_data, NULL);
-       if (task == NULL) {
-               TALLOC_FREE(ev);
-               TALLOC_FREE(ev2);
-               exit(0);
-       }
-
-       {
-               int default_children;
-               default_children = lpcfg_prefork_children(lp_ctx);
-               num_children = lpcfg_parm_int(lp_ctx, NULL, "prefork children",
-                                             service_name, default_children);
-       }
-       if (num_children == 0) {
-               DBG_WARNING("Number of pre-fork children for %s is zero, "
-                           "NO worker processes will be started for %s\n",
-                           service_name, service_name);
-       }
-       DBG_NOTICE("Forking %d %s worker processes\n",
-                  num_children, service_name);
-       {
-               int ret;
-               ret = pipe(control_pipe);
-               if (ret != 0) {
-                       smb_panic("Unable to create worker control pipe\n");
-               }
-               smb_set_close_on_exec(control_pipe[0]);
-               smb_set_close_on_exec(control_pipe[1]);
-       }
-
-       /*
-        * We are now free to spawn some worker processes
-        */
-       for (i=0; i < num_children; i++) {
-               prefork_fork_worker(task,
-                                   ev,
-                                   ev2,
-                                   service_details,
-                                   service_name,
-                                   control_pipe,
-                                   &pd);
-               pd.instances++;
-       }
-
-       /* Don't listen on the sockets we just gave to the children */
-       tevent_loop_wait(ev);
-       TALLOC_FREE(ev);
-       /* We need to keep ev2 until we're finished for the messaging to work */
-       TALLOC_FREE(ev2);
-       exit(0);
+       prefork_fork_master(ev,
+                           lp_ctx,
+                           service_name,
+                           new_task_fn,
+                           private_data,
+                           service_details,
+                           0,
+                           from_parent_fd);
 
 }