jobs: Separate internal threads from others
[src/app-framework-binder.git] / src / jobs.c
index 1e84c82..f5c9dde 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2016, 2017 "IoT.bzh"
+ * Copyright (C) 2016, 2017, 2018 "IoT.bzh"
  * Author José Bollo <jose.bollo@iot.bzh>
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
 
 #define _GNU_SOURCE
 
+#if defined(NO_JOBS_WATCHDOG)
+#   define HAS_WATCHDOG 0
+#else
+#   define HAS_WATCHDOG 1
+#endif
+
 #include <stdlib.h>
 #include <stdint.h>
 #include <unistd.h>
 #include <signal.h>
+#include <string.h>
 #include <time.h>
 #include <sys/syscall.h>
 #include <pthread.h>
 #include <errno.h>
 #include <assert.h>
+#include <sys/eventfd.h>
 
 #include <systemd/sd-event.h>
+#include "fdev.h"
+#if HAS_WATCHDOG
+#include <systemd/sd-daemon.h>
+#endif
 
 #include "jobs.h"
 #include "sig-monitor.h"
 #include "verbose.h"
 
-#if 0
-#define _alert_ "do you really want to remove monitoring?"
-#define sig_monitor_init_timeouts()  ((void)0)
-#define sig_monitor_clean_timeouts() ((void)0)
-#define sig_monitor(to,cb,arg)       (cb(0,arg))
+#if defined(REMOVE_SYSTEMD_EVENT)
+#include "fdev-epoll.h"
 #endif
 
 #define EVENT_TIMEOUT_TOP      ((uint64_t)-1)
 #define EVENT_TIMEOUT_CHILD    ((uint64_t)10000)
 
+struct thread;
+
 /** Internal shortcut for callback */
 typedef void (*job_cb_t)(int, void*);
 
@@ -50,7 +61,7 @@ typedef void (*job_cb_t)(int, void*);
 struct job
 {
        struct job *next;    /**< link to the next job enqueued */
-       void *group;         /**< group of the request */
+       const void *group;   /**< group of the request */
        job_cb_t callback;   /**< processing callback */
        void *arg;           /**< argument */
        int timeout;         /**< timeout in second for processing the request */
@@ -59,29 +70,33 @@ struct job
 };
 
 /** Description of handled event loops */
-struct events
+struct evloop
 {
-       struct events *next;
-       struct sd_event *event;
-       uint64_t timeout;
-       unsigned runs: 1;
+       unsigned state;        /**< encoded state */
+       int efd;               /**< event notification */
+       struct sd_event *sdev; /**< the systemd event loop */
+       struct fdev *fdev;     /**< handling of events */
+       struct thread *holder; /**< holder of the evloop */
 };
 
+#define EVLOOP_STATE_WAIT           1U
+#define EVLOOP_STATE_RUN            2U
+
 /** Description of threads */
 struct thread
 {
        struct thread *next;   /**< next thread of the list */
        struct thread *upper;  /**< upper same thread */
+       struct thread *nholder;/**< next holder for evloop */
+       pthread_cond_t *cwhold;/**< condition wait for holding */
        struct job *job;       /**< currently processed job */
-       struct events *events; /**< currently processed job */
        pthread_t tid;         /**< the thread id */
-       unsigned stop: 1;      /**< stop requested */
-       unsigned lowered: 1;   /**< has a lower same thread */
-       unsigned waits: 1;     /**< is waiting? */
+       volatile unsigned stop: 1;      /**< stop requested */
+       volatile unsigned waits: 1;     /**< is waiting? */
 };
 
 /**
- * Description of synchonous callback
+ * Description of synchronous callback
  */
 struct sync
 {
@@ -99,22 +114,28 @@ struct sync
 static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
 static pthread_cond_t  cond = PTHREAD_COND_INITIALIZER;
 
-/* count allowed, started and waiting threads */
+/* count allowed, started and running threads */
 static int allowed = 0; /** allowed count of threads */
 static int started = 0; /** started count of threads */
-static int waiting = 0; /** waiting count of threads */
+static int running = 0; /** running count of threads */
 static int remains = 0; /** allowed count of waiting jobs */
-static int nevents = 0; /** count of events */
 
 /* list of threads */
 static struct thread *threads;
-static _Thread_local struct thread *current;
+static _Thread_local struct thread *current_thread;
 
 /* queue of pending jobs */
 static struct job *first_job;
-static struct events *first_events;
 static struct job *free_jobs;
 
+/* event loop */
+static struct evloop evloop;
+
+#if defined(REMOVE_SYSTEMD_EVENT)
+static struct fdev_epoll *fdevepoll;
+static int waitevt;
+#endif
+
 /**
  * Create a new job with the given parameters
  * @param group    the group of the job
@@ -124,7 +145,7 @@ static struct job *free_jobs;
  * @return the created job unblock or NULL when no more memory
  */
 static struct job *job_create(
-               void *group,
+               const void *group,
                int timeout,
                job_cb_t callback,
                void *arg)
@@ -136,12 +157,13 @@ static struct job *job_create(
        if (job)
                free_jobs = job->next;
        else {
-               /* allocation  without blocking */
+               /* allocation without blocking */
                pthread_mutex_unlock(&mutex);
                job = malloc(sizeof *job);
                pthread_mutex_lock(&mutex);
                if (!job) {
-                       errno = -ENOMEM;
+                       ERROR("out of memory");
+                       errno = ENOMEM;
                        goto end;
                }
        }
@@ -163,7 +185,7 @@ end:
  */
 static void job_add(struct job *job)
 {
-       void *group;
+       const void *group;
        struct job *ijob, **pjob;
 
        /* prepare to add */
@@ -182,6 +204,7 @@ static void job_add(struct job *job)
 
        /* queue the jobs */
        *pjob = job;
+       remains--;
 }
 
 /**
@@ -193,21 +216,11 @@ static inline struct job *job_get()
        struct job *job = first_job;
        while (job && job->blocked)
                job = job->next;
+       if (job)
+               remains++;
        return job;
 }
 
-/**
- * Get the next events to process or NULL if none.
- * @return the first events that isn't running or NULL
- */
-static inline struct events *events_get()
-{
-       struct events *events = first_events;
-       while (events && events->runs)
-               events = events->next;
-       return events;
-}
-
 /**
  * Releases the processed 'job': removes it
  * from the list of jobs and unblock the first
@@ -217,7 +230,7 @@ static inline struct events *events_get()
 static inline void job_release(struct job *job)
 {
        struct job *ijob, **pjob;
-       void *group;
+       const void *group;
 
        /* first unqueue the job */
        pjob = &first_job;
@@ -259,6 +272,23 @@ static void job_cancel(int signum, void *arg)
        job->callback(SIGABRT, job->arg);
 }
 
+#if defined(REMOVE_SYSTEMD_EVENT)
+/**
+ * Gets a fdev_epoll item.
+ * @return a fdev_epoll or NULL in case of error
+ */
+static struct fdev_epoll *get_fdevepoll()
+{
+       struct fdev_epoll *result;
+
+       result = fdevepoll;
+       if (!result)
+               result = fdevepoll = fdev_epoll_create();
+
+       return result;
+}
+#endif
+
 /**
  * Monitored normal callback for events.
  * This function is called by the monitor
@@ -269,53 +299,198 @@ static void job_cancel(int signum, void *arg)
  *               flow
  * @param arg     the events to run
  */
-static void events_call(int signum, void *arg)
+static void evloop_run(int signum, void *arg)
+{
+       int rc;
+       struct sd_event *se;
+
+       if (!signum) {
+               se = evloop.sdev;
+               rc = sd_event_prepare(se);
+               if (rc < 0) {
+                       errno = -rc;
+                       CRITICAL("sd_event_prepare returned an error (state: %d): %m", sd_event_get_state(se));
+                       abort();
+               } else {
+                       if (rc == 0) {
+                               rc = sd_event_wait(se, (uint64_t)(int64_t)-1);
+                               if (rc < 0) {
+                                       errno = -rc;
+                                       ERROR("sd_event_wait returned an error (state: %d): %m", sd_event_get_state(se));
+                               }
+                       }
+                       evloop.state = EVLOOP_STATE_RUN;
+                       if (rc > 0) {
+                               rc = sd_event_dispatch(se);
+                               if (rc < 0) {
+                                       errno = -rc;
+                                       ERROR("sd_event_dispatch returned an error (state: %d): %m", sd_event_get_state(se));
+                               }
+                       }
+               }
+       }
+}
+
+/**
+ * Internal callback for evloop management.
+ * The effect of this function is hidden: it exits
+ * the waiting poll if any.
+ */
+static void evloop_on_efd_event()
 {
-       struct events *events = arg;
-       if (!signum)
-               sd_event_run(events->event, events->timeout);
+       uint64_t x;
+       read(evloop.efd, &x, sizeof x);
 }
 
 /**
- * Main processing loop of threads processing jobs.
- * The loop must be called with the mutex locked
- * and it returns with the mutex locked.
- * @param me the description of the thread to use
- * TODO: how are timeout handled when reentering?
+ * wakeup the event loop if needed by sending
+ * an event.
  */
-static void thread_run(volatile struct thread *me)
+static void evloop_wakeup()
 {
-       struct thread **prv;
-       struct job *job;
-       struct events *events;
-       uint64_t evto;
+       uint64_t x;
+
+       if (evloop.state & EVLOOP_STATE_WAIT) {
+               x = 1;
+               write(evloop.efd, &x, sizeof x);
+       }
+}
+
+/**
+ * Release the currently held event loop
+ */
+static void evloop_release()
+{
+       struct thread *nh, *ct = current_thread;
+
+       if (evloop.holder == ct) {
+               nh = ct->nholder;
+               evloop.holder = nh;
+               if (nh)
+                       pthread_cond_signal(nh->cwhold);
+       }
+}
+
+/**
+ * get the eventloop for the current thread
+ */
+static int evloop_get()
+{
+       struct thread *ct = current_thread;
+
+       if (evloop.holder)
+               return evloop.holder == ct;
+
+       ct->nholder = NULL;
+       evloop.holder = ct;
+       return 1;
+}
+
+/**
+ * acquire the eventloop for the current thread
+ */
+static void evloop_acquire()
+{
+       struct thread **pwait, *ct;
+       pthread_cond_t cond;
+
+       /* try to get the evloop */
+       if (!evloop_get()) {
+               /* failed, init waiting state */
+               ct = current_thread;
+               ct->nholder = NULL;
+               ct->cwhold = &cond;
+               pthread_cond_init(&cond, NULL);
+
+               /* queue current thread in holder list */
+               pwait = &evloop.holder;
+               while (*pwait)
+                       pwait = &(*pwait)->nholder;
+               *pwait = ct;
+
+               /* wake up the evloop */
+               evloop_wakeup();
+
+               /* wait to acquire the evloop */
+               pthread_cond_wait(&cond, &mutex);
+               pthread_cond_destroy(&cond);
+       }
+}
+
+#if defined(REMOVE_SYSTEMD_EVENT)
+/**
+ * Monitored normal loop for waiting events.
+ * @param signum 0 on normal flow or the number
+ *               of the signal that interrupted the normal
+ *               flow
+ * @param arg     the events to run
+ */
+static void monitored_wait_and_dispatch(int signum, void *arg)
+{
+       struct fdev_epoll *fdev_epoll = arg;
+       if (!signum) {
+               fdev_epoll_wait_and_dispatch(fdev_epoll, -1);
+       }
+}
+#endif
 
+/**
+ * Enter the thread
+ * @param me the description of the thread to enter
+ */
+static void thread_enter(volatile struct thread *me)
+{
        /* initialize description of itself and link it in the list */
        me->tid = pthread_self();
        me->stop = 0;
-       me->lowered = 0;
        me->waits = 0;
-       me->upper = current;
-       if (current) {
-               current->lowered = 1;
-               evto = EVENT_TIMEOUT_CHILD;
-       } else {
-               started++;
-               sig_monitor_init_timeouts();
-               evto = EVENT_TIMEOUT_TOP;
-       }
+       me->upper = current_thread;
        me->next = threads;
        threads = (struct thread*)me;
-       current = (struct thread*)me;
+       current_thread = (struct thread*)me;
+}
+
+/**
+ * leave the thread
+ * @param me the description of the thread to leave
+ */
+static void thread_leave()
+{
+       struct thread **prv, *me;
+
+       /* unlink the current thread and cleanup */
+       me = current_thread;
+       prv = &threads;
+       while (*prv != me)
+               prv = &(*prv)->next;
+       *prv = me->next;
+
+       current_thread = me->upper;
+}
+
+/**
+ * Main processing loop of internal threads with processing jobs.
+ * The loop must be called with the mutex locked
+ * and it returns with the mutex locked.
+ * @param me the description of the thread to use
+ * TODO: how are timeout handled when reentering?
+ */
+static void thread_run_internal(volatile struct thread *me)
+{
+       struct job *job;
+
+       /* enter thread */
+       thread_enter(me);
 
        /* loop until stopped */
-       me->events = NULL;
        while (!me->stop) {
+               /* release the current event loop */
+               evloop_release();
+
                /* get a job */
-               job = job_get(first_job);
+               job = job_get();
                if (job) {
                        /* prepare running the job */
-                       remains++; /* increases count of job that can wait */
                        job->blocked = 1; /* mark job as blocked */
                        me->job = job; /* record the job (only for terminate) */
 
@@ -326,49 +501,87 @@ static void thread_run(volatile struct thread *me)
 
                        /* release the run job */
                        job_release(job);
-
-                       /* release event if any */
-                       events = me->events;
-                       if (events) {
-                               events->runs = 0;
-                               me->events = NULL;
+#if !defined(REMOVE_SYSTEMD_EVENT)
+               /* no job, check event loop wait */
+               } else if (evloop_get()) {
+                       if (evloop.state != 0) {
+                               /* busy ? */
+                               CRITICAL("Can't enter dispatch while in dispatch!");
+                               abort();
                        }
+                       /* run the events */
+                       evloop.state = EVLOOP_STATE_RUN|EVLOOP_STATE_WAIT;
+                       pthread_mutex_unlock(&mutex);
+                       sig_monitor(0, evloop_run, NULL);
+                       pthread_mutex_lock(&mutex);
+                       evloop.state = 0;
                } else {
-                       /* no job, check events */
-                       events = events_get();
-                       if (events) {
-                               /* run the events */
-                               events->runs = 1;
-                               events->timeout = evto;
-                               me->events = events;
-                               pthread_mutex_unlock(&mutex);
-                               sig_monitor(0, events_call, events);
-                               pthread_mutex_lock(&mutex);
-                               events->runs = 0;
-                               me->events = NULL;
-                       } else {
-                               /* no job and not events */
-                               waiting++;
-                               me->waits = 1;
-                               pthread_cond_wait(&cond, &mutex);
-                               me->waits = 0;
-                               waiting--;
-                       }
+                       /* no job and no event loop */
+                       running--;
+                       if (!running)
+                               ERROR("Entering job deep sleep! Check your bindings.");
+                       me->waits = 1;
+                       pthread_cond_wait(&cond, &mutex);
+                       me->waits = 0;
+                       running++;
+#else
+               } else if (waitevt) {
+                       /* no job and not events */
+                       running--;
+                       if (!running)
+                               ERROR("Entering job deep sleep! Check your bindings.");
+                       me->waits = 1;
+                       pthread_cond_wait(&cond, &mutex);
+                       me->waits = 0;
+                       running++;
+               } else {
+                       /* wait for events */
+                       waitevt = 1;
+                       pthread_mutex_unlock(&mutex);
+                       sig_monitor(0, monitored_wait_and_dispatch, get_fdevepoll());
+                       pthread_mutex_lock(&mutex);
+                       waitevt = 0;
+#endif
                }
        }
+       /* cleanup */
+       evloop_release();
+       thread_leave();
+}
 
-       /* unlink the current thread and cleanup */
-       prv = &threads;
-       while (*prv != me)
-               prv = &(*prv)->next;
-       *prv = me->next;
-       current = me->upper;
-       if (current) {
-               current->lowered = 0;
-       } else {
-               sig_monitor_clean_timeouts();
-               started--;
-       }
+/**
+ * Main processing loop of external threads.
+ * The loop must be called with the mutex locked
+ * and it returns with the mutex locked.
+ * @param me the description of the thread to use
+ */
+static void thread_run_external(volatile struct thread *me)
+{
+       /* enter thread */
+       thread_enter(me);
+
+       /* loop until stopped */
+       me->waits = 1;
+       while (!me->stop)
+               pthread_cond_wait(&cond, &mutex);
+       me->waits = 0;
+       thread_leave();
+}
+
+/**
+ * Root for created threads.
+ */
+static void thread_main()
+{
+       struct thread me;
+
+       running++;
+       started++;
+       sig_monitor_init_timeouts();
+       thread_run_internal(&me);
+       sig_monitor_clean_timeouts();
+       started--;
+       running--;
 }
 
 /**
@@ -376,12 +589,10 @@ static void thread_run(volatile struct thread *me)
  * @param data not used
  * @return NULL
  */
-static void *thread_main(void *data)
+static void *thread_starter(void *data)
 {
-       struct thread me;
-
        pthread_mutex_lock(&mutex);
-       thread_run(&me);
+       thread_main();
        pthread_mutex_unlock(&mutex);
        return NULL;
 }
@@ -395,7 +606,7 @@ static int start_one_thread()
        pthread_t tid;
        int rc;
 
-       rc = pthread_create(&tid, NULL, thread_main, NULL);
+       rc = pthread_create(&tid, NULL, thread_starter, NULL);
        if (rc != 0) {
                /* errno = rc; */
                WARNING("not able to start thread: %m");
@@ -422,12 +633,11 @@ static int start_one_thread()
  * @return 0 in case of success or -1 in case of error
  */
 int jobs_queue(
-               void *group,
+               const void *group,
                int timeout,
                void (*callback)(int, void*),
                void *arg)
 {
-       const char *info;
        struct job *job;
        int rc;
 
@@ -435,31 +645,27 @@ int jobs_queue(
 
        /* allocates the job */
        job = job_create(group, timeout, callback, arg);
-       if (!job) {
-               errno = ENOMEM;
-               info = "out of memory";
+       if (!job)
                goto error;
-       }
 
        /* check availability */
-       if (remains == 0) {
+       if (remains <= 0) {
+               ERROR("can't process job with threads: too many jobs");
                errno = EBUSY;
-               info = "too many jobs";
                goto error2;
        }
 
        /* start a thread if needed */
-       if (waiting == 0 && started < allowed) {
+       if (running == started && started < allowed) {
                /* all threads are busy and a new can be started */
                rc = start_one_thread();
                if (rc < 0 && started == 0) {
-                       info = "can't start first thread";
+                       ERROR("can't start initial thread: %m");
                        goto error2;
                }
        }
 
        /* queues the job */
-       remains--;
        job_add(job);
 
        /* signal an existing job */
@@ -471,7 +677,6 @@ error2:
        job->next = free_jobs;
        free_jobs = job;
 error:
-       ERROR("can't process job with threads: %s, %m", info);
        pthread_mutex_unlock(&mutex);
        return -1;
 }
@@ -504,7 +709,7 @@ static void call_cb(int signum, void *closure)
  * @see jobs_call, jobs_enter, jobs_leave
  */
 static int do_sync(
-               void *group,
+               const void *group,
                int timeout,
                void (*sync_cb)(int signum, void *closure),
                struct sync *sync
@@ -517,8 +722,6 @@ static int do_sync(
        /* allocates the job */
        job = job_create(group, timeout, sync_cb, sync);
        if (!job) {
-               ERROR("out of memory");
-               errno = ENOMEM;
                pthread_mutex_unlock(&mutex);
                return -1;
        }
@@ -527,7 +730,10 @@ static int do_sync(
        job_add(job);
 
        /* run until stopped */
-       thread_run(&sync->thread);
+       if (current_thread)
+               thread_run_internal(&sync->thread);
+       else
+               thread_run_external(&sync->thread);
        pthread_mutex_unlock(&mutex);
        return 0;
 }
@@ -544,11 +750,11 @@ static int do_sync(
  *                 of interrupted flow, the context 'closure' as given and
  *                 a 'jobloop' reference that must be used when the job is
  *                 terminated to unlock the current execution flow.
- * @param arg the argument to the callback
+ * @param closure the argument to the callback
  * @return 0 on success or -1 in case of error
  */
 int jobs_enter(
-               void *group,
+               const void *group,
                int timeout,
                void (*callback)(int signum, void *closure, struct jobloop *jobloop),
                void *closure
@@ -580,6 +786,8 @@ int jobs_leave(struct jobloop *jobloop)
                t->stop = 1;
                if (t->waits)
                        pthread_cond_broadcast(&cond);
+               else
+                       evloop_wakeup();
        }
        pthread_mutex_unlock(&mutex);
        return -!t;
@@ -600,7 +808,7 @@ int jobs_leave(struct jobloop *jobloop)
  * @return 0 in case of success or -1 in case of error
  */
 int jobs_call(
-               void *group,
+               const void *group,
                int timeout,
                void (*callback)(int, void*),
                void *arg)
@@ -613,74 +821,147 @@ int jobs_call(
        return do_sync(group, timeout, call_cb, &sync);
 }
 
+/**
+ * Internal callback for evloop management.
+ * The effect of this function is hidden: it exits
+ * the waiting poll if any. Then it wakes up a thread
+ * awaiting the evloop using signal.
+ */
+static int on_evloop_efd(sd_event_source *s, int fd, uint32_t revents, void *userdata)
+{
+       evloop_on_efd_event();
+       return 1;
+}
+
+/* temporary hack */
+#if !defined(REMOVE_SYSTEMD_EVENT)
+__attribute__((unused))
+#endif
+static void evloop_callback(void *arg, uint32_t event, struct fdev *fdev)
+{
+       sig_monitor(0, evloop_run, arg);
+}
+
 /**
  * Gets a sd_event item for the current thread.
  * @return a sd_event or NULL in case of error
  */
-struct sd_event *jobs_get_sd_event()
+static struct sd_event *get_sd_event_locked()
 {
-       struct events *events;
-       struct thread *me;
        int rc;
 
-       pthread_mutex_lock(&mutex);
-
-       /* search events on stack */
-       me = current;
-       while (me && !me->events)
-               me = me->upper;
-       if (me)
-               /* return the stacked events */
-               events = me->events;
-       else {
-               /* search an available events */
-               events = events_get();
-               if (!events) {
-                       /* not found, check if creation possible */
-                       if (nevents >= allowed) {
-                               ERROR("not possible to add a new event");
-                               events = NULL;
-                       } else {
-                               events = malloc(sizeof *events);
-                               if (events && (rc = sd_event_new(&events->event)) >= 0) {
-                                       if (nevents < started || start_one_thread() >= 0) {
-                                               events->runs = 0;
-                                               events->next = first_events;
-                                               first_events = events;
-                                       } else {
-                                               ERROR("can't start thread for events");
-                                               sd_event_unref(events->event);
-                                               free(events);
-                                               events = NULL;
-                                       }
-                               } else {
-                                       if (!events) {
-                                               ERROR("out of memory");
-                                               errno = ENOMEM;
-                                       } else {
-                                               free(events);
-                                               ERROR("creation of sd_event failed: %m");
-                                               events = NULL;
-                                               errno = -rc;
-                                       } 
-                               }
-                       }
+       /* creates the evloop on need */
+       if (!evloop.sdev) {
+               /* start the creation */
+               evloop.state = 0;
+               /* creates the eventfd for waking up polls */
+               evloop.efd = eventfd(0, EFD_CLOEXEC|EFD_SEMAPHORE);
+               if (evloop.efd < 0) {
+                       ERROR("can't make eventfd for events");
+                       goto error1;
                }
-               if (events) {
-                       /* */
-                       me = current;
-                       if (me) {
-                               events->runs = 1;
-                               me->events = events;
-                       } else {
-                               WARNING("event returned for unknown thread!");
-                       }
+               /* create the systemd event loop */
+               rc = sd_event_new(&evloop.sdev);
+               if (rc < 0) {
+                       ERROR("can't make new event loop");
+                       goto error2;
+               }
+               /* put the eventfd in the event loop */
+               rc = sd_event_add_io(evloop.sdev, NULL, evloop.efd, EPOLLIN, on_evloop_efd, NULL);
+               if (rc < 0) {
+                       ERROR("can't register eventfd");
+#if !defined(REMOVE_SYSTEMD_EVENT)
+                       sd_event_unref(evloop.sdev);
+                       evloop.sdev = NULL;
+error2:
+                       close(evloop.efd);
+error1:
+                       return NULL;
+               }
+#else
+                       goto error3;
+               }
+               /* handle the event loop */
+               evloop.fdev = fdev_epoll_add(get_fdevepoll(), sd_event_get_fd(evloop.sdev));
+               if (!evloop.fdev) {
+                       ERROR("can't create fdev");
+error3:
+                       sd_event_unref(evloop.sdev);
+error2:
+                       close(evloop.efd);
+error1:
+                       memset(&evloop, 0, sizeof evloop);
+                       return NULL;
                }
+               fdev_set_autoclose(evloop.fdev, 0);
+               fdev_set_events(evloop.fdev, EPOLLIN);
+               fdev_set_callback(evloop.fdev, evloop_callback, NULL);
+#endif
+       }
+
+       /* acquire the event loop */
+       evloop_acquire();
+
+       return evloop.sdev;
+}
+
+/**
+ * Gets a sd_event item for the current thread.
+ * @return a sd_event or NULL in case of error
+ */
+struct sd_event *jobs_get_sd_event()
+{
+       struct sd_event *result;
+       struct thread lt;
+
+       /* ensure an existing thread environment */
+       if (!current_thread) {
+               memset(&lt, 0, sizeof lt);
+               current_thread = &lt;
        }
+
+       /* process */
+       pthread_mutex_lock(&mutex);
+       result = get_sd_event_locked();
        pthread_mutex_unlock(&mutex);
-       return events ? events->event : NULL;
+
+       /* release the faked thread environment if needed */
+       if (current_thread == &lt) {
+               /*
+                * Releasing it is needed because there is no way to guess
+                * when it has to be released really. But here is where it is
+                * hazardous: if the caller modifies the eventloop when it
+                * is waiting, there is no way to make the change effective.
+                * A workaround to achieve that goal is for the caller to
+                * require the event loop a second time after having modified it.
+                */
+               NOTICE("Requiring sd_event loop out of binder callbacks is hazardous!");
+               if (verbose_wants(Log_Level_Info))
+                       sig_monitor_dumpstack();
+               evloop_release();
+               current_thread = NULL;
+       }
+
+       return result;
 }
 
+#if defined(REMOVE_SYSTEMD_EVENT)
+/**
+ * Gets the fdev_epoll item.
+ * @return a fdev_epoll or NULL in case of error
+ */
+struct fdev_epoll *jobs_get_fdev_epoll()
+{
+       struct fdev_epoll *result;
+
+       pthread_mutex_lock(&mutex);
+       result = get_fdevepoll();
+       pthread_mutex_unlock(&mutex);
+
+       return result;
+}
+#endif
+
 /**
  * Enter the jobs processing loop.
  * @param allowed_count Maximum count of thread for jobs including this one
@@ -689,10 +970,9 @@ struct sd_event *jobs_get_sd_event()
  * @param start         The start routine to activate (can't be NULL)
  * @return 0 in case of success or -1 in case of error.
  */
-int jobs_start(int allowed_count, int start_count, int waiter_count, void (*start)(int signum))
+int jobs_start(int allowed_count, int start_count, int waiter_count, void (*start)(int signum, void* arg), void *arg)
 {
        int rc, launched;
-       struct thread me;
        struct job *job;
 
        assert(allowed_count >= 1);
@@ -704,27 +984,27 @@ int jobs_start(int allowed_count, int start_count, int waiter_count, void (*star
        pthread_mutex_lock(&mutex);
 
        /* check whether already running */
-       if (current || allowed) {
+       if (current_thread || allowed) {
                ERROR("thread already started");
                errno = EINVAL;
                goto error;
        }
 
-       /* start */
-       if (sig_monitor_init() < 0) {
-               ERROR("failed to initialise signal handlers");
-               goto error;
-       }
-
        /* records the allowed count */
        allowed = allowed_count;
        started = 0;
-       waiting = 0;
+       running = 0;
        remains = waiter_count;
 
-       /* start at least one thread */
-       launched = 0;
-       while ((launched + 1) < start_count) {
+#if HAS_WATCHDOG
+       /* set the watchdog */
+       if (sd_watchdog_enabled(0, NULL))
+               sd_event_set_watchdog(get_sd_event_locked(), 1);
+#endif
+
+       /* start at least one thread: the current one */
+       launched = 1;
+       while (launched < start_count) {
                if (start_one_thread() != 0) {
                        ERROR("Not all threads can be started");
                        goto error;
@@ -733,17 +1013,13 @@ int jobs_start(int allowed_count, int start_count, int waiter_count, void (*star
        }
 
        /* queue the start job */
-       job = job_create(NULL, 0, (job_cb_t)start, NULL);
-       if (!job) {
-               ERROR("out of memory");
-               errno = ENOMEM;
+       job = job_create(NULL, 0, start, arg);
+       if (!job)
                goto error;
-       }
        job_add(job);
-       remains--;
 
        /* run until end */
-       thread_run(&me);
+       thread_main();
        rc = 0;
 error:
        pthread_mutex_unlock(&mutex);
@@ -811,7 +1087,7 @@ void jobs_terminate()
                head = job->next;
 
                /* search if job is stacked for current */
-               t = current;
+               t = current_thread;
                while (t && t->job != job)
                        t = t->upper;
                if (t) {