From 42c8a5ab9bdcf8c139f1c5a558e64d39716a6582 Mon Sep 17 00:00:00 2001 From: Patrik Nyblom Date: Fri, 19 Feb 2010 16:25:54 +0100 Subject: Support monitoring and demonitoring from driver threads The driver in the wx application does monitoring (and demonitoring) from non-scheduler threads. In the non-half-word emulators, data will be modified without the protection of a lock (which is potentially bad), but the half-word emulator will crash in that situation. While at it, also correct an old bug which make assertions fail in the Kernel test suite. --- erts/emulator/beam/io.c | 232 +++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 210 insertions(+), 22 deletions(-) (limited to 'erts/emulator/beam/io.c') diff --git a/erts/emulator/beam/io.c b/erts/emulator/beam/io.c index 0a2a2c60e2..10f1082039 100644 --- a/erts/emulator/beam/io.c +++ b/erts/emulator/beam/io.c @@ -72,6 +72,15 @@ erts_driver_t fd_driver; static int init_driver(erts_driver_t *, ErlDrvEntry *, DE_Handle *); static void terminate_port(Port *p); static void pdl_init(void); +#ifdef ERTS_SMP +static void driver_monitor_lock_pdl(Port *p); +static void driver_monitor_unlock_pdl(Port *p); +#define DRV_MONITOR_LOCK_PDL(Port) driver_monitor_lock_pdl(Port) +#define DRV_MONITOR_UNLOCK_PDL(Port) driver_monitor_unlock_pdl(Port) +#else +#define DRV_MONITOR_LOCK_PDL(Port) /* nothing */ +#define DRV_MONITOR_UNLOCK_PDL(Port) /* nothing */ +#endif static ERTS_INLINE ErlIOQueue* drvport2ioq(ErlDrvPort drvport) @@ -1998,12 +2007,13 @@ erts_do_exit_port(Port *p, Eterm from, Eterm reason) p->nlinks = NULL; erts_sweep_links(lnk, &sweep_one_link, &sc); } + DRV_MONITOR_LOCK_PDL(p); { ErtsMonitor *moni = p->monitors; p->monitors = NULL; erts_sweep_monitors(moni, &sweep_one_monitor, NULL); } - + DRV_MONITOR_UNLOCK_PDL(p); if ((p->status & ERTS_PORT_SFLG_DISTRIBUTION) && p->dist_entry) { erts_do_net_exits(p->dist_entry, rreason); @@ -3536,6 +3546,32 @@ static ERTS_INLINE void pdl_destroy(ErlDrvPDL pdl) erts_free(ERTS_ALC_T_PORT_DATA_LOCK, pdl); } +#ifdef ERTS_SMP + +static void driver_monitor_lock_pdl(Port *p) { + if (p->port_data_lock) { + driver_pdl_lock(p->port_data_lock); + } + /* Now we either have the port lock or the port_data_lock */ + ERTS_LC_ASSERT(!p->port_data_lock + || erts_lc_mtx_is_locked(&(p->port_data_lock->mtx))); + ERTS_SMP_LC_ASSERT(p->port_data_lock + || erts_lc_is_port_locked(p)); +} + +static void driver_monitor_unlock_pdl(Port *p) { + /* We should either have the port lock or the port_data_lock */ + ERTS_LC_ASSERT(!p->port_data_lock + || erts_lc_mtx_is_locked(&(p->port_data_lock->mtx))); + ERTS_SMP_LC_ASSERT(p->port_data_lock + || erts_lc_is_port_locked(p)); + if (p->port_data_lock) { + driver_pdl_unlock(p->port_data_lock); + } +} + +#endif + /* * exported driver_pdl_* functions ... */ @@ -4076,14 +4112,14 @@ static void ref_to_driver_monitor(Eterm ref, ErlDrvMonitor *mon) memcpy(mon,refp,sizeof(RefThing)); } -int driver_monitor_process(ErlDrvPort port, - ErlDrvTermData process, - ErlDrvMonitor *monitor) + +static int do_driver_monitor_process(Port *prt, + Eterm *buf, + ErlDrvTermData process, + ErlDrvMonitor *monitor) { - Port *prt = erts_drvport2port(port); Process *rp; Eterm ref; - DeclareTmpHeapNoproc(buf,REF_THING_SIZE); if (prt->drv_ptr->process_exit == NULL) { return -1; @@ -4094,29 +4130,79 @@ int driver_monitor_process(ErlDrvPort port, if (!rp) { return 1; } - UseTmpHeapNoproc(REF_THING_SIZE); + ref = erts_make_ref_in_buffer(buf); erts_add_monitor(&(prt->monitors), MON_ORIGIN, ref, rp->id, NIL); erts_add_monitor(&(rp->monitors), MON_TARGET, ref, prt->id, NIL); - + erts_smp_proc_unlock(rp, ERTS_PROC_LOCK_LINK); ref_to_driver_monitor(ref,monitor); - UnUseTmpHeapNoproc(REF_THING_SIZE); return 0; } -int driver_demonitor_process(ErlDrvPort port, - const ErlDrvMonitor *monitor) +/* + * This can be called from a non scheduler thread iff a port_data_lock exists + */ +int driver_monitor_process(ErlDrvPort port, + ErlDrvTermData process, + ErlDrvMonitor *monitor) +{ + Port *prt; + int ret; + Uint32 status; + ErtsSchedulerData *sched = erts_get_scheduler_data(); + int ix = (int) port; + if (ix < 0 || erts_max_ports <= ix) { + return -1; + } + prt = &erts_port[ix]; + + DRV_MONITOR_LOCK_PDL(prt); + + if (sched) { + status = erts_port[ix].status; + } else { + erts_smp_port_state_lock(prt); + status = erts_port[ix].status; + erts_smp_port_state_unlock(prt); + } + + if (status & ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP) { + DRV_MONITOR_UNLOCK_PDL(prt); + return -1; + } + + /* Now (in SMP) we should have either the port lock (if we have a scheduler) or the port data lock + (if we're a driver thread) */ + ERTS_SMP_LC_ASSERT((sched != NULL || prt->port_data_lock)); + +#if !HEAP_ON_C_STACK + if (!sched) { + /* Need a separate allocation for the ref :( */ + Eterm *buf = erts_alloc(ERTS_ALC_T_TEMP_TERM, + sizeof(Eterm)*REF_THING_SIZE); + ret = do_driver_monitor_process(prt,buf,process,monitor); + erts_free(ERTS_ALC_T_TEMP_TERM,buf); + } else +#endif + { + DeclareTmpHeapNoproc(buf,REF_THING_SIZE); + UseTmpHeapNoproc(REF_THING_SIZE); + ret = do_driver_monitor_process(prt,buf,process,monitor); + UnUseTmpHeapNoproc(REF_THING_SIZE); + } + DRV_MONITOR_UNLOCK_PDL(prt); + return ret; +} + +static int do_driver_demonitor_process(Port *prt, Eterm *buf, + const ErlDrvMonitor *monitor) { - Port *prt = erts_drvport2port(port); Process *rp; Eterm ref; - DeclareTmpHeapNoproc(buf,REF_THING_SIZE); ErtsMonitor *mon; Eterm to; - - UseTmpHeapNoproc(REF_THING_SIZE); memcpy(buf,monitor,sizeof(Eterm)*REF_THING_SIZE); ref = make_internal_ref(buf); mon = erts_lookup_monitor(prt->monitors, ref); @@ -4143,20 +4229,66 @@ int driver_demonitor_process(ErlDrvPort port, erts_destroy_monitor(rmon); } } - UnUseTmpHeapNoproc(REF_THING_SIZE); return 0; } -ErlDrvTermData driver_get_monitored_process(ErlDrvPort port, +int driver_demonitor_process(ErlDrvPort port, + const ErlDrvMonitor *monitor) +{ + Port *prt; + int ret; + Uint32 status; + ErtsSchedulerData *sched = erts_get_scheduler_data(); + int ix = (int) port; + if (ix < 0 || erts_max_ports <= ix) { + return -1; + } + prt = &erts_port[ix]; + + DRV_MONITOR_LOCK_PDL(prt); + + if (sched) { + status = erts_port[ix].status; + } else { + erts_smp_port_state_lock(prt); + status = erts_port[ix].status; + erts_smp_port_state_unlock(prt); + } + + if (status & ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP) { + DRV_MONITOR_UNLOCK_PDL(prt); + return -1; + } + + /* Now we should have either the port lock (if we have a scheduler) or the port data lock + (if we're a driver thread) */ + ERTS_SMP_LC_ASSERT((sched != NULL || prt->port_data_lock)); +#if !HEAP_ON_C_STACK + if (!sched) { + /* Need a separate allocation for the ref :( */ + Eterm *buf = erts_alloc(ERTS_ALC_T_TEMP_TERM, + sizeof(Eterm)*REF_THING_SIZE); + ret = do_driver_demonitor_process(prt,buf,monitor); + erts_free(ERTS_ALC_T_TEMP_TERM,buf); + } else +#endif + { + DeclareTmpHeapNoproc(buf,REF_THING_SIZE); + UseTmpHeapNoproc(REF_THING_SIZE); + ret = do_driver_demonitor_process(prt,buf,monitor); + UnUseTmpHeapNoproc(REF_THING_SIZE); + } + DRV_MONITOR_UNLOCK_PDL(prt); + return ret; +} + +static ErlDrvTermData do_driver_get_monitored_process(Port *prt, Eterm *buf, const ErlDrvMonitor *monitor) { - Port *prt = erts_drvport2port(port); Eterm ref; - DeclareTmpHeapNoproc(buf,REF_THING_SIZE); ErtsMonitor *mon; Eterm to; - UseTmpHeapNoproc(REF_THING_SIZE); memcpy(buf,monitor,sizeof(Eterm)*REF_THING_SIZE); ref = make_internal_ref(buf); mon = erts_lookup_monitor(prt->monitors, ref); @@ -4166,10 +4298,62 @@ ErlDrvTermData driver_get_monitored_process(ErlDrvPort port, ASSERT(mon->type == MON_ORIGIN); to = mon->pid; ASSERT(is_internal_pid(to)); - UnUseTmpHeapNoproc(REF_THING_SIZE); return (ErlDrvTermData) to; } + +ErlDrvTermData driver_get_monitored_process(ErlDrvPort port, + const ErlDrvMonitor *monitor) +{ + Port *prt; + ErlDrvTermData ret; + Uint32 status; + ErtsSchedulerData *sched = erts_get_scheduler_data(); + int ix = (int) port; + if (ix < 0 || erts_max_ports <= ix) { + return driver_term_nil; + } + prt = &erts_port[ix]; + + DRV_MONITOR_LOCK_PDL(prt); + + if (sched) { + status = erts_port[ix].status; + } else { + erts_smp_port_state_lock(prt); + status = erts_port[ix].status; + erts_smp_port_state_unlock(prt); + } + + if (status & ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP) { + DRV_MONITOR_UNLOCK_PDL(prt); + return driver_term_nil; + } + + /* Now we should have either the port lock (if we have a scheduler) or the port data lock + (if we're a driver thread) */ + ERTS_SMP_LC_ASSERT((sched != NULL || prt->port_data_lock)); + +#if !HEAP_ON_C_STACK + if (!sched) { + /* Need a separate allocation for the ref :( */ + Eterm *buf = erts_alloc(ERTS_ALC_T_TEMP_TERM, + sizeof(Eterm)*REF_THING_SIZE); + ret = do_driver_get_monitored_process(prt,buf,monitor); + erts_free(ERTS_ALC_T_TEMP_TERM,buf); + } else +#endif + { + DeclareTmpHeapNoproc(buf,REF_THING_SIZE); + UseTmpHeapNoproc(REF_THING_SIZE); + ret = do_driver_get_monitored_process(prt,buf,monitor); + UnUseTmpHeapNoproc(REF_THING_SIZE); + } + DRV_MONITOR_UNLOCK_PDL(prt); + return ret; +} + + int driver_compare_monitors(const ErlDrvMonitor *monitor1, const ErlDrvMonitor *monitor2) { @@ -4185,18 +4369,22 @@ void erts_fire_port_monitor(Port *prt, Eterm ref) ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt)); ASSERT(prt->drv_ptr != NULL); - + DRV_MONITOR_LOCK_PDL(prt); if (erts_lookup_monitor(prt->monitors,ref) == NULL) { + DRV_MONITOR_UNLOCK_PDL(prt); return; } callback = prt->drv_ptr->process_exit; ASSERT(callback != NULL); ref_to_driver_monitor(ref,&drv_monitor); + DRV_MONITOR_UNLOCK_PDL(prt); fpe_was_unmasked = erts_block_fpe(); (*callback)((ErlDrvData) (prt->drv_data), &drv_monitor); erts_unblock_fpe(fpe_was_unmasked); + DRV_MONITOR_LOCK_PDL(prt); /* remove monitor *after* callback */ rmon = erts_remove_monitor(&(prt->monitors),ref); + DRV_MONITOR_UNLOCK_PDL(prt); if (rmon) { erts_destroy_monitor(rmon); 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