/*
* erts_pid2proc_safelock() is called from erts_pid2proc_opt() when
* it wasn't possible to trylock all locks needed.
* c_p - current process
* c_p_have_locks - locks held on c_p
* pid - process id of process we are looking up
* proc - process struct of process we are looking
* up (both in and out argument)
* need_locks - all locks we need (including have_locks)
* pix_lock - pix lock for process we are looking up
* flags - option flags
*/
void
erts_pid2proc_safelock(Process *c_p,
ErtsProcLocks c_p_have_locks,
Process **proc,
ErtsProcLocks need_locks,
erts_pix_lock_t *pix_lock,
int flags)
{
Process *p = *proc;
ERTS_LC_ASSERT(p->lock.refc > 0);
ERTS_LC_ASSERT(process_tab[internal_pid_index(p->id)] == p);
p->lock.refc++;
erts_pix_unlock(pix_lock);
proc_safelock(c_p,
c_p ? ERTS_PID2PIXLOCK(c_p->id) : NULL,
c_p_have_locks,
c_p_have_locks,
p,
pix_lock,
0,
need_locks);
erts_pix_lock(pix_lock);
if (!p->is_exiting
|| ((flags & ERTS_P2P_FLG_ALLOW_OTHER_X)
&& process_tab[internal_pid_index(p->id)] == p)) {
ERTS_LC_ASSERT(p->lock.refc > 1);
p->lock.refc--;
}
else {
/* No proc. Note, we need to keep refc until after process unlock */
erts_pix_unlock(pix_lock);
erts_smp_proc_unlock__(p, pix_lock, need_locks);
*proc = NULL;
erts_pix_lock(pix_lock);
ERTS_LC_ASSERT(p->lock.refc > 0);
if (--p->lock.refc == 0) {
erts_pix_unlock(pix_lock);
erts_free_proc(p);
erts_pix_lock(pix_lock);
}
}
}
Eterm
check_process_code_2(BIF_ALIST_2)
{
Process* rp;
Module* modp;
if (is_not_atom(BIF_ARG_2)) {
goto error;
}
if (is_internal_pid(BIF_ARG_1)) {
Eterm res;
if (internal_pid_index(BIF_ARG_1) >= erts_max_processes)
goto error;
modp = erts_get_module(BIF_ARG_2);
if (modp == NULL) { /* Doesn't exist. */
return am_false;
} else if (modp->old_code == NULL) { /* No old code. */
return am_false;
}
#ifdef ERTS_SMP
rp = erts_pid2proc_suspend(BIF_P, ERTS_PROC_LOCK_MAIN,
BIF_ARG_1, ERTS_PROC_LOCK_MAIN);
#else
rp = erts_pid2proc(BIF_P, 0, BIF_ARG_1, 0);
#endif
if (!rp) {
BIF_RET(am_false);
}
if (rp == ERTS_PROC_LOCK_BUSY) {
ERTS_BIF_YIELD2(bif_export[BIF_check_process_code_2], BIF_P,
BIF_ARG_1, BIF_ARG_2);
}
res = check_process_code(rp, modp);
#ifdef ERTS_SMP
if (BIF_P != rp) {
erts_resume(rp, ERTS_PROC_LOCK_MAIN);
erts_smp_proc_unlock(rp, ERTS_PROC_LOCK_MAIN);
}
#endif
BIF_RET(res);
}
else if (is_external_pid(BIF_ARG_1)
&& external_pid_dist_entry(BIF_ARG_1) == erts_this_dist_entry) {
BIF_RET(am_false);
}
error:
BIF_ERROR(BIF_P, BADARG);
}
Eterm
check_process_code_2(BIF_ALIST_2)
{
Process* rp;
Module* modp;
if (is_not_atom(BIF_ARG_2)) {
goto error;
}
if (is_internal_pid(BIF_ARG_1)) {
Eterm res;
if (internal_pid_index(BIF_ARG_1) >= erts_max_processes)
goto error;
rp = erts_pid2proc_not_running(BIF_P, ERTS_PROC_LOCK_MAIN,
BIF_ARG_1, ERTS_PROC_LOCK_MAIN);
if (!rp) {
BIF_RET(am_false);
}
if (rp == ERTS_PROC_LOCK_BUSY) {
ERTS_BIF_YIELD2(bif_export[BIF_check_process_code_2], BIF_P,
BIF_ARG_1, BIF_ARG_2);
}
modp = erts_get_module(BIF_ARG_2);
res = check_process_code(rp, modp);
#ifdef ERTS_SMP
if (BIF_P != rp)
erts_smp_proc_unlock(rp, ERTS_PROC_LOCK_MAIN);
#endif
BIF_RET(res);
}
else if (is_external_pid(BIF_ARG_1)
&& external_pid_dist_entry(BIF_ARG_1) == erts_this_dist_entry) {
BIF_RET(am_false);
}
error:
BIF_ERROR(BIF_P, BADARG);
}
Process *
erts_pid2proc_opt(Process *c_p,
ErtsProcLocks c_p_have_locks,
Eterm pid,
ErtsProcLocks pid_need_locks,
int flags)
{
Process *dec_refc_proc = NULL;
ErtsThrPrgrDelayHandle dhndl;
ErtsProcLocks need_locks;
Uint pix;
Process *proc;
#if ERTS_PROC_LOCK_OWN_IMPL && defined(ERTS_ENABLE_LOCK_COUNT)
ErtsProcLocks lcnt_locks;
#endif
#ifdef ERTS_ENABLE_LOCK_CHECK
if (c_p) {
ErtsProcLocks might_unlock = c_p_have_locks & pid_need_locks;
if (might_unlock)
erts_proc_lc_might_unlock(c_p, might_unlock);
}
#endif
if (is_not_internal_pid(pid))
return NULL;
pix = internal_pid_index(pid);
ERTS_LC_ASSERT((pid_need_locks & ERTS_PROC_LOCKS_ALL) == pid_need_locks);
need_locks = pid_need_locks;
if (c_p && c_p->common.id == pid) {
ASSERT(c_p->common.id != ERTS_INVALID_PID);
ASSERT(c_p == erts_pix2proc(pix));
if (!(flags & ERTS_P2P_FLG_ALLOW_OTHER_X)
&& ERTS_PROC_IS_EXITING(c_p))
return NULL;
need_locks &= ~c_p_have_locks;
if (!need_locks) {
if (flags & ERTS_P2P_FLG_INC_REFC)
erts_proc_inc_refc(c_p);
return c_p;
}
}
dhndl = erts_thr_progress_unmanaged_delay();
proc = (Process *) erts_ptab_pix2intptr_ddrb(&erts_proc, pix);
if (proc) {
if (proc->common.id != pid)
proc = NULL;
else if (!need_locks) {
if (flags & ERTS_P2P_FLG_INC_REFC)
erts_proc_inc_refc(proc);
}
else {
int busy;
#if ERTS_PROC_LOCK_OWN_IMPL
#ifdef ERTS_ENABLE_LOCK_COUNT
lcnt_locks = need_locks;
if (!(flags & ERTS_P2P_FLG_TRY_LOCK)) {
erts_lcnt_proc_lock(&proc->lock, need_locks);
}
#endif
#ifdef ERTS_ENABLE_LOCK_CHECK
/* Make sure erts_pid2proc_safelock() is enough to handle
a potential lock order violation situation... */
busy = erts_proc_lc_trylock_force_busy(proc, need_locks);
if (!busy)
#endif
#endif /* ERTS_PROC_LOCK_OWN_IMPL */
{
/* Try a quick trylock to grab all the locks we need. */
busy = (int) erts_smp_proc_raw_trylock__(proc, need_locks);
#if ERTS_PROC_LOCK_OWN_IMPL && defined(ERTS_ENABLE_LOCK_CHECK)
erts_proc_lc_trylock(proc, need_locks, !busy, __FILE__,__LINE__);
#endif
#ifdef ERTS_PROC_LOCK_DEBUG
if (!busy)
erts_proc_lock_op_debug(proc, need_locks, 1);
#endif
}
#if ERTS_PROC_LOCK_OWN_IMPL && defined(ERTS_ENABLE_LOCK_COUNT)
if (flags & ERTS_P2P_FLG_TRY_LOCK)
erts_lcnt_proc_trylock(&proc->lock, need_locks,
busy ? EBUSY : 0);
#endif
if (!busy) {
if (flags & ERTS_P2P_FLG_INC_REFC)
erts_proc_inc_refc(proc);
#if ERTS_PROC_LOCK_OWN_IMPL && defined(ERTS_ENABLE_LOCK_COUNT)
/* all is great */
if (!(flags & ERTS_P2P_FLG_TRY_LOCK))
erts_lcnt_proc_lock_post_x(&proc->lock, lcnt_locks,
__FILE__, __LINE__);
#endif
}
else {
if (flags & ERTS_P2P_FLG_TRY_LOCK)
proc = ERTS_PROC_LOCK_BUSY;
else {
int managed;
if (flags & ERTS_P2P_FLG_INC_REFC)
erts_proc_inc_refc(proc);
#if ERTS_PROC_LOCK_OWN_IMPL && defined(ERTS_ENABLE_LOCK_COUNT)
erts_lcnt_proc_lock_unaquire(&proc->lock, lcnt_locks);
#endif
managed = dhndl == ERTS_THR_PRGR_DHANDLE_MANAGED;
if (!managed) {
erts_proc_inc_refc(proc);
erts_thr_progress_unmanaged_continue(dhndl);
dec_refc_proc = proc;
/*
* We don't want to call
* erts_thr_progress_unmanaged_continue()
* again.
*/
dhndl = ERTS_THR_PRGR_DHANDLE_MANAGED;
}
proc_safelock(managed,
c_p,
c_p_have_locks,
c_p_have_locks,
proc,
0,
need_locks);
}
}
}
}
if (dhndl != ERTS_THR_PRGR_DHANDLE_MANAGED)
erts_thr_progress_unmanaged_continue(dhndl);
if (need_locks
&& proc
&& proc != ERTS_PROC_LOCK_BUSY
&& (!(flags & ERTS_P2P_FLG_ALLOW_OTHER_X)
? ERTS_PROC_IS_EXITING(proc)
: (proc
!= (Process *) erts_ptab_pix2intptr_nob(&erts_proc, pix)))) {
erts_smp_proc_unlock(proc, need_locks);
if (flags & ERTS_P2P_FLG_INC_REFC)
dec_refc_proc = proc;
proc = NULL;
}
if (dec_refc_proc)
erts_proc_dec_refc(dec_refc_proc);
#if ERTS_PROC_LOCK_OWN_IMPL && defined(ERTS_PROC_LOCK_DEBUG)
ERTS_LC_ASSERT(!proc
|| proc == ERTS_PROC_LOCK_BUSY
|| (pid_need_locks ==
(ERTS_PROC_LOCK_FLGS_READ_(&proc->lock)
& pid_need_locks)));
#endif
return proc;
}
Process *
erts_pid2proc_opt(Process *c_p,
ErtsProcLocks c_p_have_locks,
Eterm pid,
ErtsProcLocks pid_need_locks,
int flags)
{
Process *dec_refc_proc = NULL;
int need_ptl;
ErtsProcLocks need_locks;
Uint pix;
Process *proc;
#if ERTS_PROC_LOCK_OWN_IMPL && defined(ERTS_ENABLE_LOCK_COUNT)
ErtsProcLocks lcnt_locks;
#endif
#ifdef ERTS_ENABLE_LOCK_CHECK
if (c_p) {
ErtsProcLocks might_unlock = c_p_have_locks & pid_need_locks;
if (might_unlock)
erts_proc_lc_might_unlock(c_p, might_unlock);
}
#endif
if (is_not_internal_pid(pid))
return NULL;
pix = internal_pid_index(pid);
ERTS_LC_ASSERT((pid_need_locks & ERTS_PROC_LOCKS_ALL) == pid_need_locks);
need_locks = pid_need_locks;
if (c_p && c_p->id == pid) {
ASSERT(c_p->id != ERTS_INVALID_PID);
ASSERT(c_p == erts_pix2proc(pix));
if (!(flags & ERTS_P2P_FLG_ALLOW_OTHER_X)
&& ERTS_PROC_IS_EXITING(c_p))
return NULL;
need_locks &= ~c_p_have_locks;
if (!need_locks) {
if (flags & ERTS_P2P_FLG_SMP_INC_REFC)
erts_smp_proc_inc_refc(c_p);
return c_p;
}
}
need_ptl = !erts_get_scheduler_id();
if (need_ptl)
erts_smp_rwmtx_rwlock(&erts_proc_tab_rwmtx);
proc = (Process *) erts_smp_atomic_read_ddrb(&erts_proc.tab[pix]);
if (proc) {
if (proc->id != pid)
proc = NULL;
else if (!need_locks) {
if (flags & ERTS_P2P_FLG_SMP_INC_REFC)
erts_smp_proc_inc_refc(proc);
}
else {
int busy;
#if ERTS_PROC_LOCK_OWN_IMPL
#ifdef ERTS_ENABLE_LOCK_COUNT
lcnt_locks = need_locks;
if (!(flags & ERTS_P2P_FLG_TRY_LOCK)) {
erts_lcnt_proc_lock(&proc->lock, need_locks);
}
#endif
#ifdef ERTS_ENABLE_LOCK_CHECK
/* Make sure erts_pid2proc_safelock() is enough to handle
a potential lock order violation situation... */
busy = erts_proc_lc_trylock_force_busy(proc, need_locks);
if (!busy)
#endif
#endif /* ERTS_PROC_LOCK_OWN_IMPL */
{
/* Try a quick trylock to grab all the locks we need. */
busy = (int) erts_smp_proc_raw_trylock__(proc, need_locks);
#if ERTS_PROC_LOCK_OWN_IMPL && defined(ERTS_ENABLE_LOCK_CHECK)
erts_proc_lc_trylock(proc, need_locks, !busy);
#endif
#ifdef ERTS_PROC_LOCK_DEBUG
if (!busy)
erts_proc_lock_op_debug(proc, need_locks, 1);
#endif
}
#if ERTS_PROC_LOCK_OWN_IMPL && defined(ERTS_ENABLE_LOCK_COUNT)
if (flags & ERTS_P2P_FLG_TRY_LOCK)
erts_lcnt_proc_trylock(&proc->lock, need_locks,
busy ? EBUSY : 0);
#endif
if (!busy) {
if (flags & ERTS_P2P_FLG_SMP_INC_REFC)
erts_smp_proc_inc_refc(proc);
#if ERTS_PROC_LOCK_OWN_IMPL && defined(ERTS_ENABLE_LOCK_COUNT)
/* all is great */
if (!(flags & ERTS_P2P_FLG_TRY_LOCK))
erts_lcnt_proc_lock_post_x(&proc->lock, lcnt_locks,
__FILE__, __LINE__);
#endif
}
else {
if (flags & ERTS_P2P_FLG_TRY_LOCK)
proc = ERTS_PROC_LOCK_BUSY;
else {
if (flags & ERTS_P2P_FLG_SMP_INC_REFC)
erts_smp_proc_inc_refc(proc);
#if ERTS_PROC_LOCK_OWN_IMPL && defined(ERTS_ENABLE_LOCK_COUNT)
erts_lcnt_proc_lock_unaquire(&proc->lock, lcnt_locks);
#endif
if (need_ptl) {
erts_smp_proc_inc_refc(proc);
dec_refc_proc = proc;
erts_smp_rwmtx_rwunlock(&erts_proc_tab_rwmtx);
need_ptl = 0;
}
proc_safelock(!need_ptl,
c_p,
c_p_have_locks,
c_p_have_locks,
proc,
0,
need_locks);
}
}
}
}
if (need_ptl)
erts_smp_rwmtx_rwunlock(&erts_proc_tab_rwmtx);
if (need_locks
&& proc
&& proc != ERTS_PROC_LOCK_BUSY
&& (!(flags & ERTS_P2P_FLG_ALLOW_OTHER_X)
? ERTS_PROC_IS_EXITING(proc)
: (proc
!= (Process *) erts_smp_atomic_read_nob(&erts_proc.tab[pix])))) {
erts_smp_proc_unlock(proc, need_locks);
if (flags & ERTS_P2P_FLG_SMP_INC_REFC)
dec_refc_proc = proc;
proc = NULL;
}
if (dec_refc_proc)
erts_smp_proc_dec_refc(dec_refc_proc);
#if ERTS_PROC_LOCK_OWN_IMPL && defined(ERTS_PROC_LOCK_DEBUG)
ERTS_LC_ASSERT(!proc
|| proc == ERTS_PROC_LOCK_BUSY
|| (pid_need_locks ==
(ERTS_PROC_LOCK_FLGS_READ_(&proc->lock)
& pid_need_locks)));
#endif
return proc;
}