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/*
* Proc structure hash table indexed by proctabid() (usually getpid()).
* No lock is necessary for lookups (important when called from signal
* handlers).
*
* To be included from other files (e.g., Linux-clone.c).
*/
#define T ((void*)-1)
enum
{
PTABHASH = 1031,
};
static Lock ptablock;
static Proc *proctab[PTABHASH];
static Proc *theproc;
static int multi;
void
_threadmultiproc(void)
{
if(multi == 0){
multi = 1;
_threadsetproc(theproc);
}
}
void
_threadsetproc(Proc *p)
{
int i, h;
Proc **t;
if(!multi){
theproc = p;
return;
}
lock(&ptablock);
p->procid = procid();
h = p->procid%PTABHASH;
for(i=0; i<PTABHASH; i++){
t = &proctab[(h+i)%PTABHASH];
if(*t==nil || *t==T){
*t = p;
break;
}
}
unlock(&ptablock);
if(i == PTABHASH)
sysfatal("too many procs - proctab is full");
}
static Proc**
_threadfindproc(int id)
{
int i, h;
Proc **t;
if(!multi)
return &theproc;
h = id%PTABHASH;
for(i=0; i<PTABHASH; i++){
t = &proctab[(h+i)%PTABHASH];
if(*t != nil && *t != T && (*t)->procid == id){
unlock(&ptablock);
return t;
}
}
return nil;
}
Proc*
_threadgetproc(void)
{
Proc **t;
t = _threadfindproc(procid());
if(t == nil)
return nil;
return *t;
}
Proc*
_threaddelproc(void)
{
Proc **t, *p;
t = _threadfindproc(procid());
if(t == nil)
return nil;
p = *t;
*t = T;
return p;
}
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