static Port*
id_or_name2port(Process *c_p, Eterm id)
{
Port *port;
if (is_not_atom(id))
port = erts_id2port(id, c_p, ERTS_PROC_LOCK_MAIN);
else
erts_whereis_name(c_p, ERTS_PROC_LOCK_MAIN, id, NULL, 0, 0, &port);
return port;
}
/*
* Unregister a name
* Return 0 if not registered
* Otherwise returns 1
*
*/
int erts_unregister_name(Process *c_p,
ErtsProcLocks c_p_locks,
Port *c_prt,
Eterm name)
{
int res = 0;
RegProc r, *rp;
Port *port = c_prt;
ErtsProcLocks current_c_p_locks = 0;
#ifdef ERTS_SMP
/*
* SMP note: If 'c_prt != NULL' and 'c_prt->reg->name == name',
* we are *not* allowed to temporarily release the lock
* on c_prt.
*/
if (!c_p) {
c_p_locks = 0;
}
current_c_p_locks = c_p_locks;
restart:
reg_safe_write_lock(c_p, ¤t_c_p_locks);
#endif
r.name = name;
if (is_non_value(name)) {
/* Unregister current process name */
ASSERT(c_p);
#ifdef ERTS_SMP
if (current_c_p_locks != c_p_locks) {
erts_smp_proc_lock(c_p, c_p_locks);
current_c_p_locks = c_p_locks;
}
#endif
if (c_p->common.u.alive.reg) {
r.name = c_p->common.u.alive.reg->name;
} else {
/* Name got unregistered while main lock was released */
res = 0;
goto done;
}
}
if ((rp = (RegProc*) hash_get(&process_reg, (void*) &r)) != NULL) {
if (rp->pt) {
if (port != rp->pt) {
#ifdef ERTS_SMP
if (port) {
ASSERT(port != c_prt);
erts_port_release(port);
port = NULL;
}
if (erts_smp_port_trylock(rp->pt) == EBUSY) {
Eterm id = rp->pt->common.id; /* id read only... */
/* Unlock all locks, acquire port lock, and restart... */
if (current_c_p_locks) {
erts_smp_proc_unlock(c_p, current_c_p_locks);
current_c_p_locks = 0;
}
reg_write_unlock();
port = erts_id2port(id);
goto restart;
}
#endif
port = rp->pt;
}
ASSERT(rp->pt == port);
ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(port));
rp->pt->common.u.alive.reg = NULL;
if (IS_TRACED_FL(port, F_TRACE_PORTS)) {
if (current_c_p_locks) {
erts_smp_proc_unlock(c_p, current_c_p_locks);
current_c_p_locks = 0;
}
trace_port(port, am_unregister, r.name);
}
} else if (rp->p) {
#ifdef ERTS_SMP
erts_proc_safelock(c_p,
current_c_p_locks,
c_p_locks,
rp->p,
(c_p == rp->p) ? current_c_p_locks : 0,
ERTS_PROC_LOCK_MAIN);
current_c_p_locks = c_p_locks;
#endif
rp->p->common.u.alive.reg = NULL;
if (IS_TRACED_FL(rp->p, F_TRACE_PROCS)) {
trace_proc(rp->p, (c_p == rp->p) ? c_p_locks : ERTS_PROC_LOCK_MAIN,
rp->p, am_unregister, r.name);
}
#ifdef ERTS_SMP
if (rp->p != c_p) {
erts_smp_proc_unlock(rp->p, ERTS_PROC_LOCK_MAIN);
}
#endif
}
hash_erase(&process_reg, (void*) &r);
res = 1;
}
done:
reg_write_unlock();
if (c_prt != port) {
if (port) {
erts_port_release(port);
}
if (c_prt) {
erts_smp_port_lock(c_prt);
}
}
#ifdef ERTS_SMP
if (c_p && !current_c_p_locks) {
erts_smp_proc_lock(c_p, c_p_locks);
}
#endif
return res;
}
void
erts_whereis_name(Process *c_p,
ErtsProcLocks c_p_locks,
Eterm name,
Process** proc,
ErtsProcLocks need_locks,
int flags,
Port** port,
int lock_port)
{
RegProc* rp = NULL;
HashValue hval;
int ix;
HashBucket* b;
#ifdef ERTS_SMP
ErtsProcLocks current_c_p_locks;
Port *pending_port = NULL;
if (!c_p)
c_p_locks = 0;
current_c_p_locks = c_p_locks;
restart:
reg_safe_read_lock(c_p, ¤t_c_p_locks);
/* Locked locks:
* - port lock on pending_port if pending_port != NULL
* - read reg lock
* - current_c_p_locks (either c_p_locks or 0) on c_p
*/
#endif
hval = REG_HASH(name);
ix = hval % process_reg.size;
b = process_reg.bucket[ix];
/*
* Note: We have inlined the code from hash.c for speed.
*/
while (b) {
if (((RegProc *) b)->name == name) {
rp = (RegProc *) b;
break;
}
b = b->next;
}
if (proc) {
if (!rp)
*proc = NULL;
else {
#ifdef ERTS_SMP
if (!rp->p)
*proc = NULL;
else {
if (need_locks) {
erts_proc_safelock(c_p,
current_c_p_locks,
c_p_locks,
rp->p,
0,
need_locks);
current_c_p_locks = c_p_locks;
}
if ((flags & ERTS_P2P_FLG_ALLOW_OTHER_X) || is_proc_alive(rp->p))
*proc = rp->p;
else {
if (need_locks)
erts_smp_proc_unlock(rp->p, need_locks);
*proc = NULL;
}
}
#else
if (rp->p
&& ((flags & ERTS_P2P_FLG_ALLOW_OTHER_X) || is_proc_alive(rp->p)))
*proc = rp->p;
else
*proc = NULL;
#endif
if (*proc && (flags & ERTS_P2P_FLG_INC_REFC))
erts_proc_inc_refc(*proc);
}
}
if (port) {
if (!rp || !rp->pt)
*port = NULL;
else {
#ifdef ERTS_SMP
if (lock_port) {
if (pending_port == rp->pt)
pending_port = NULL;
else {
if (pending_port) {
/* Ahh! Registered port changed while reg lock
was unlocked... */
erts_port_release(pending_port);
pending_port = NULL;
}
if (erts_smp_port_trylock(rp->pt) == EBUSY) {
Eterm id = rp->pt->common.id; /* id read only... */
/* Unlock all locks, acquire port lock, and restart... */
if (current_c_p_locks) {
erts_smp_proc_unlock(c_p, current_c_p_locks);
current_c_p_locks = 0;
}
reg_read_unlock();
pending_port = erts_id2port(id);
goto restart;
}
}
ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(rp->pt));
}
#endif
*port = rp->pt;
}
}
#ifdef ERTS_SMP
if (c_p && !current_c_p_locks)
erts_smp_proc_lock(c_p, c_p_locks);
if (pending_port)
erts_port_release(pending_port);
#endif
reg_read_unlock();
}
/*
* Register a process or port (can't be registered twice).
* Returns 0 if name, process or port is already registered.
*
* When smp support is enabled:
* * Assumes that main lock is locked (and only main lock)
* on c_p.
*
*/
int erts_register_name(Process *c_p, Eterm name, Eterm id)
{
int res = 0;
Process *proc = NULL;
Port *port = NULL;
RegProc r, *rp;
ERTS_SMP_CHK_HAVE_ONLY_MAIN_PROC_LOCK(c_p);
if (is_not_atom(name) || name == am_undefined)
return res;
if (c_p->common.id == id) /* A very common case I think... */
proc = c_p;
else {
if (is_not_internal_pid(id) && is_not_internal_port(id))
return res;
erts_smp_proc_unlock(c_p, ERTS_PROC_LOCK_MAIN);
if (is_internal_port(id)) {
port = erts_id2port(id);
if (!port)
goto done;
}
}
#ifdef ERTS_SMP
{
ErtsProcLocks proc_locks = proc ? ERTS_PROC_LOCK_MAIN : 0;
reg_safe_write_lock(proc, &proc_locks);
if (proc && !proc_locks)
erts_smp_proc_lock(c_p, ERTS_PROC_LOCK_MAIN);
}
#endif
if (is_internal_pid(id)) {
if (!proc)
proc = erts_pid2proc(NULL, 0, id, ERTS_PROC_LOCK_MAIN);
r.p = proc;
if (!proc)
goto done;
if (proc->common.u.alive.reg)
goto done;
r.pt = NULL;
}
else {
ASSERT(!INVALID_PORT(port, id));
ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(port));
r.pt = port;
if (r.pt->common.u.alive.reg)
goto done;
r.p = NULL;
}
r.name = name;
rp = (RegProc*) hash_put(&process_reg, (void*) &r);
if (proc && rp->p == proc) {
if (IS_TRACED_FL(proc, F_TRACE_PROCS)) {
trace_proc(proc, ERTS_PROC_LOCK_MAIN,
proc, am_register, name);
}
proc->common.u.alive.reg = rp;
}
else if (port && rp->pt == port) {
if (IS_TRACED_FL(port, F_TRACE_PORTS)) {
trace_port(port, am_register, name);
}
port->common.u.alive.reg = rp;
}
if ((rp->p && rp->p->common.id == id)
|| (rp->pt && rp->pt->common.id == id)) {
res = 1;
}
done:
reg_write_unlock();
if (port)
erts_port_release(port);
if (c_p != proc) {
if (proc)
erts_smp_proc_unlock(proc, ERTS_PROC_LOCK_MAIN);
erts_smp_proc_lock(c_p, ERTS_PROC_LOCK_MAIN);
}
return res;
}
/*
* Unregister a name
* Return 0 if not registered
* Otherwise returns 1
*
*/
int erts_unregister_name(Process *c_p,
ErtsProcLocks c_p_locks,
Port *c_prt,
Eterm name)
{
int res = 0;
RegProc r, *rp;
Port *port = c_prt;
#ifdef ERTS_SMP
ErtsProcLocks current_c_p_locks;
/*
* SMP note: If 'c_prt != NULL' and 'c_prt->reg->name == name',
* we are *not* allowed to temporarily release the lock
* on c_prt.
*/
if (!c_p)
c_p_locks = 0;
current_c_p_locks = c_p_locks;
restart:
reg_safe_write_lock(c_p, ¤t_c_p_locks);
#endif
r.name = name;
if ((rp = (RegProc*) hash_get(&process_reg, (void*) &r)) != NULL) {
if (rp->pt) {
#ifdef ERTS_SMP
if (port != rp->pt) {
if (port) {
ERTS_SMP_LC_ASSERT(port != c_prt);
erts_smp_port_unlock(port);
port = NULL;
}
if (erts_smp_port_trylock(rp->pt) == EBUSY) {
Eterm id = rp->pt->id; /* id read only... */
/* Unlock all locks, acquire port lock, and restart... */
if (current_c_p_locks) {
erts_smp_proc_unlock(c_p, current_c_p_locks);
current_c_p_locks = 0;
}
reg_read_unlock();
port = erts_id2port(id, NULL, 0);
goto restart;
}
port = rp->pt;
}
#endif
ERTS_SMP_LC_ASSERT(rp->pt == port && erts_lc_is_port_locked(port));
rp->pt->reg = NULL;
if (IS_TRACED_FL(port, F_TRACE_PORTS)) {
trace_port(port, am_unregister, name);
}
} else if (rp->p) {
Process* p = rp->p;
#ifdef ERTS_SMP
erts_proc_safelock(c_p,
current_c_p_locks,
c_p_locks,
rp->p,
0,
ERTS_PROC_LOCK_MAIN);
current_c_p_locks = c_p_locks;
#endif
p->reg = NULL;
#ifdef ERTS_SMP
if (rp->p != c_p)
erts_smp_proc_unlock(rp->p, ERTS_PROC_LOCK_MAIN);
#endif
if (IS_TRACED_FL(p, F_TRACE_PROCS)) {
trace_proc(c_p, p, am_unregister, name);
}
}
hash_erase(&process_reg, (void*) &r);
res = 1;
}
reg_write_unlock();
if (c_prt != port) {
if (port)
erts_smp_port_unlock(port);
if (c_prt)
erts_smp_port_lock(c_prt);
}
#ifdef ERTS_SMP
if (c_p && !current_c_p_locks)
erts_smp_proc_lock(c_p, c_p_locks);
#endif
return res;
}
