This is a live mirror of the Perl 5 development currently hosted at https://github.com/perl/perl5
static functions should be prefixed S_
[perl5.git] / ext / threads / threads.xs
index 043f762..baf1b51 100755 (executable)
@@ -5,44 +5,28 @@
 
 #ifdef USE_ITHREADS
 
+
 #ifdef WIN32
 #include <windows.h>
 #include <win32thread.h>
-#define PERL_THREAD_SETSPECIFIC(k,v) TlsSetValue(k,v)
-#define PERL_THREAD_GETSPECIFIC(k,v) v = TlsGetValue(k)
-#define PERL_THREAD_ALLOC_SPECIFIC(k) \
-STMT_START {\
-  if((k = TlsAlloc()) == TLS_OUT_OF_INDEXES) {\
-    PerlIO_printf(PerlIO_stderr(),"panic threads.h: TlsAlloc");\
-    exit(1);\
-  }\
-} STMT_END
+#else
+#ifdef OS2
+typedef perl_os_thread pthread_t;
 #else
 #include <pthread.h>
+#endif
 #include <thread.h>
-
 #define PERL_THREAD_SETSPECIFIC(k,v) pthread_setspecific(k,v)
 #ifdef OLD_PTHREADS_API
 #define PERL_THREAD_DETACH(t) pthread_detach(&(t))
-#define PERL_THREAD_GETSPECIFIC(k,v) pthread_getspecific(k,&v)
-#define PERL_THREAD_ALLOC_SPECIFIC(k) STMT_START {\
-  if(pthread_keycreate(&(k),0)) {\
-    PerlIO_printf(PerlIO_stderr(), "panic threads.h: pthread_key_create");\
-    exit(1);\
-  }\
-} STMT_END
 #else
 #define PERL_THREAD_DETACH(t) pthread_detach((t))
-#define PERL_THREAD_GETSPECIFIC(k,v) v = pthread_getspecific(k)
-#define PERL_THREAD_ALLOC_SPECIFIC(k) STMT_START {\
-  if(pthread_key_create(&(k),0)) {\
-    PerlIO_printf(PerlIO_stderr(), "panic threads.h: pthread_key_create");\
-    exit(1);\
-  }\
-} STMT_END
-#endif
+#endif  /* OLD_PTHREADS_API */
 #endif
 
+
+
+
 /* Values for 'state' member */
 #define PERL_ITHR_JOINABLE             0
 #define PERL_ITHR_DETACHED             1
@@ -50,16 +34,16 @@ STMT_START {\
 #define PERL_ITHR_JOINED               2
 
 typedef struct ithread_s {
-    struct ithread_s *next;    /* next thread in the list */
-    struct ithread_s *prev;    /* prev thread in the list */
+    struct ithread_s *next;    /* Next thread in the list */
+    struct ithread_s *prev;    /* Prev thread in the list */
     PerlInterpreter *interp;   /* The threads interpreter */
-    I32 tid;                   /* threads module's thread id */
-    perl_mutex mutex;          /* mutex for updating things in this struct */
-    I32 count;                 /* how many SVs have a reference to us */
-    signed char state;         /* are we detached ? */
+    I32 tid;                   /* Threads module's thread id */
+    perl_mutex mutex;          /* Mutex for updating things in this struct */
+    I32 count;                 /* How many SVs have a reference to us */
+    signed char state;         /* Are we detached ? */
     int gimme;                 /* Context of create */
     SV* init_function;          /* Code to run */
-    SV* params;                 /* args to pass function */
+    SV* params;                 /* Args to pass function */
 #ifdef WIN32
        DWORD   thr;            /* OS's idea if thread id */
        HANDLE handle;          /* OS's waitable handle */
@@ -83,17 +67,71 @@ static perl_mutex create_destruct_mutex;  /* protects the creation and destructi
 I32 tid_counter = 0;
 I32 known_threads = 0;
 I32 active_threads = 0;
-perl_key self_key;
+
+
+void Perl_ithread_set (pTHX_ ithread* thread)
+{
+  SV* thread_sv = newSViv(PTR2IV(thread));
+  if(!hv_store(PL_modglobal, "threads::self", 12, thread_sv,0)) {
+    croak("%s\n","Internal error, couldn't set TLS");
+  }
+}
+
+ithread* Perl_ithread_get (pTHX) {
+  SV** thread_sv = hv_fetch(PL_modglobal, "threads::self",12,0);
+  if(!thread_sv) {
+    croak("%s\n","Internal error, couldn't get TLS");
+  }
+  return INT2PTR(ithread*,SvIV(*thread_sv));
+}
+
+
+/* free any data (such as the perl interpreter) attached to an
+ * ithread structure. This is a bit like undef on SVs, where the SV
+ * isn't freed, but the PVX is.
+ * Must be called with thread->mutex already held
+ */
+
+static void
+S_ithread_clear(pTHX_ ithread* thread)
+{
+    PerlInterpreter *interp;
+    assert(thread->state & PERL_ITHR_FINISHED &&
+           (thread->state & PERL_ITHR_DETACHED ||
+           thread->state & PERL_ITHR_JOINED));
+
+    interp = thread->interp;
+    if (interp) {
+       dTHXa(interp);
+       ithread* current_thread;
+#ifdef OEMVS
+       void *ptr;
+#endif
+       PERL_SET_CONTEXT(interp);
+       current_thread = Perl_ithread_get(aTHX);
+       Perl_ithread_set(aTHX_ thread);
+       
+       SvREFCNT_dec(thread->params);
+
+       thread->params = Nullsv;
+       perl_destruct(interp);
+       thread->interp = NULL;
+    }
+    if (interp)
+       perl_free(interp);
+    PERL_SET_CONTEXT(aTHX);
+}
+
 
 /*
- *  Clear up after thread is done with
+ *  free an ithread structure and any attached data if its count == 0
  */
 void
 Perl_ithread_destruct (pTHX_ ithread* thread, const char *why)
 {
-        PerlInterpreter* destroyperl = NULL;        
        MUTEX_LOCK(&thread->mutex);
        if (!thread->next) {
+           MUTEX_UNLOCK(&thread->mutex);
            Perl_croak(aTHX_ "panic: destruct destroyed thread %p (%s)",thread, why);
        }
        if (thread->count != 0) {
@@ -123,27 +161,16 @@ Perl_ithread_destruct (pTHX_ ithread* thread, const char *why)
 #endif
        MUTEX_UNLOCK(&create_destruct_mutex);
        /* Thread is now disowned */
-       if (thread->interp) {
-           dTHXa(thread->interp);
-           PERL_SET_CONTEXT(thread->interp);
-           SvREFCNT_dec(thread->params);
-           thread->params = Nullsv;
-           destroyperl = thread->interp;
-           thread->interp = NULL;
-       }
+
+       S_ithread_clear(aTHX_ thread);
        MUTEX_UNLOCK(&thread->mutex);
        MUTEX_DESTROY(&thread->mutex);
+#ifdef WIN32
+       if (thread->handle)
+           CloseHandle(thread->handle);
+       thread->handle = 0;
+#endif
         PerlMemShared_free(thread);
-       if(destroyperl) {
-           ithread*        current_thread;
-           PERL_THREAD_GETSPECIFIC(self_key,current_thread);
-           PERL_THREAD_SETSPECIFIC(self_key,thread);
-           perl_destruct(destroyperl);
-            perl_free(destroyperl);
-           PERL_THREAD_SETSPECIFIC(self_key,current_thread);
-
-       }
-       PERL_SET_CONTEXT(aTHX);
 }
 
 int
@@ -152,8 +179,9 @@ Perl_ithread_hook(pTHX)
     int veto_cleanup = 0;
     MUTEX_LOCK(&create_destruct_mutex);
     if (aTHX == PL_curinterp && active_threads != 1) {
-       Perl_warn(aTHX_ "A thread exited while %" IVdf " other threads were still running",
-                                               (IV)active_threads);
+       if (ckWARN_d(WARN_THREADS))
+           Perl_warn(aTHX_ "A thread exited while %" IVdf " threads were running",
+                                                     (IV)active_threads);
        veto_cleanup = 1;
     }
     MUTEX_UNLOCK(&create_destruct_mutex);
@@ -189,7 +217,7 @@ int
 ithread_mg_get(pTHX_ SV *sv, MAGIC *mg)
 {
     ithread *thread = (ithread *) mg->mg_ptr;
-    SvIVX(sv) = PTR2IV(thread);
+    SvIV_set(sv, PTR2IV(thread));
     SvIOK_on(sv);
     return 0;
 }
@@ -254,7 +282,7 @@ Perl_ithread_run(void * arg) {
        ithread* thread = (ithread*) arg;
        dTHXa(thread->interp);
        PERL_SET_CONTEXT(thread->interp);
-       PERL_THREAD_SETSPECIFIC(self_key,thread);
+       Perl_ithread_set(aTHX_ thread);
 
 #if 0
        /* Far from clear messing with ->thr child-side is a good idea */
@@ -288,7 +316,7 @@ Perl_ithread_run(void * arg) {
                  SV *sv = POPs;
                  av_store(params, i, SvREFCNT_inc(sv));
                }
-               if (SvTRUE(ERRSV)) {
+               if (SvTRUE(ERRSV) && ckWARN_d(WARN_THREADS)) {
                    Perl_warn(aTHX_ "thread failed to start: %" SVf, ERRSV);
                }
                FREETMPS;
@@ -341,20 +369,18 @@ ithread_to_SV(pTHX_ SV *obj, ithread *thread, char *classname, bool inc)
 ithread *
 SV_to_ithread(pTHX_ SV *sv)
 {
-    ithread *thread;
     if (SvROK(sv))
      {
-      thread = INT2PTR(ithread*, SvIV(SvRV(sv)));
+      return INT2PTR(ithread*, SvIV(SvRV(sv)));
      }
     else
      {
-      PERL_THREAD_GETSPECIFIC(self_key,thread);
+      return Perl_ithread_get(aTHX);
      }
-    return thread;
 }
 
 /*
- * iThread->create(); ( aka iThread->new() )
+ * ithread->create(); ( aka ithread->new() )
  * Called in context of parent thread
  */
 
@@ -363,10 +389,24 @@ Perl_ithread_create(pTHX_ SV *obj, char* classname, SV* init_function, SV* param
 {
        ithread*        thread;
        CLONE_PARAMS    clone_param;
-       ithread*        current_thread;
-       PERL_THREAD_GETSPECIFIC(self_key,current_thread);
+       ithread*        current_thread = Perl_ithread_get(aTHX);
+
+       SV**            tmps_tmp = PL_tmps_stack;
+       I32             tmps_ix  = PL_tmps_ix;
+#ifndef WIN32
+       int             failure;
+       const char*     panic = NULL;
+#endif
+
+
        MUTEX_LOCK(&create_destruct_mutex);
-       thread = PerlMemShared_malloc(sizeof(ithread));
+       thread = (ithread *) PerlMemShared_malloc(sizeof(ithread));
+       if (!thread) {  
+           MUTEX_UNLOCK(&create_destruct_mutex);
+           PerlLIO_write(PerlIO_fileno(Perl_error_log),
+                         PL_no_mem, strlen(PL_no_mem));
+           my_exit(1);
+       }
        Zero(thread,1,ithread);
        thread->next = threads;
        thread->prev = threads->prev;
@@ -385,7 +425,13 @@ Perl_ithread_create(pTHX_ SV *obj, char* classname, SV* init_function, SV* param
         */
 
        PerlIO_flush((PerlIO*)NULL);
-       PERL_THREAD_SETSPECIFIC(self_key,thread);
+       Perl_ithread_set(aTHX_ thread);
+
+       SAVEBOOL(PL_srand_called); /* Save this so it becomes the correct
+                                     value */
+       PL_srand_called = FALSE; /* Set it to false so we can detect
+                                   if it gets set during the clone */
+
 #ifdef WIN32
        thread->interp = perl_clone(aTHX, CLONEf_KEEP_PTR_TABLE | CLONEf_CLONE_HOST);
 #else
@@ -398,6 +444,7 @@ Perl_ithread_create(pTHX_ SV *obj, char* classname, SV* init_function, SV* param
         */
        {
            dTHXa(thread->interp);
+
             /* Here we remove END blocks since they should only run
               in the thread they are created
             */
@@ -408,24 +455,55 @@ Perl_ithread_create(pTHX_ SV *obj, char* classname, SV* init_function, SV* param
            if (SvREFCNT(thread->init_function) == 0) {
                SvREFCNT_inc(thread->init_function);
            }
+           
+
 
            thread->params = sv_dup(params, &clone_param);
            SvREFCNT_inc(thread->params);
+
+
+           /* The code below checks that anything living on
+              the tmps stack and has been cloned (so it lives in the
+              ptr_table) has a refcount higher than 0
+
+              If the refcount is 0 it means that a something on the
+              stack/context was holding a reference to it and
+              since we init_stacks() in perl_clone that won't get
+              cleaned and we will get a leaked scalar.
+              The reason it was cloned was that it lived on the
+              @_ stack.
+
+              Example of this can be found in bugreport 15837
+              where calls in the parameter list end up as a temp
+
+              One could argue that this fix should be in perl_clone
+           */
+              
+
+           while (tmps_ix > 0) { 
+             SV* sv = (SV*)ptr_table_fetch(PL_ptr_table, tmps_tmp[tmps_ix]);
+             tmps_ix--;
+             if (sv && SvREFCNT(sv) == 0) {
+               SvREFCNT_inc(sv);
+               SvREFCNT_dec(sv);
+             }
+           }
+           
+
+
            SvTEMP_off(thread->init_function);
            ptr_table_free(PL_ptr_table);
            PL_ptr_table = NULL;
            PL_exit_flags |= PERL_EXIT_DESTRUCT_END;
        }
-       PERL_THREAD_SETSPECIFIC(self_key,current_thread);
+       Perl_ithread_set(aTHX_ current_thread);
        PERL_SET_CONTEXT(aTHX);
 
        /* Start the thread */
 
 #ifdef WIN32
-
        thread->handle = CreateThread(NULL, 0, Perl_ithread_run,
                        (LPVOID)thread, 0, &thread->thr);
-
 #else
        {
          static pthread_attr_t attr;
@@ -440,29 +518,56 @@ Perl_ithread_create(pTHX_ SV *obj, char* classname, SV* init_function, SV* param
 #  endif
 #  ifdef THREAD_CREATE_NEEDS_STACK
            if(pthread_attr_setstacksize(&attr, THREAD_CREATE_NEEDS_STACK))
-             croak("panic: pthread_attr_setstacksize failed");
+             panic = "panic: pthread_attr_setstacksize failed";
 #  endif
 
 #ifdef OLD_PTHREADS_API
-         pthread_create( &thread->thr, attr, Perl_ithread_run, (void *)thread);
+           failure
+             = panic ? 1 : pthread_create( &thread->thr, attr,
+                                           Perl_ithread_run, (void *)thread);
 #else
-         pthread_create( &thread->thr, &attr, Perl_ithread_run, (void *)thread);
+#  if defined(HAS_PTHREAD_ATTR_SETSCOPE) && defined(PTHREAD_SCOPE_SYSTEM)
+         pthread_attr_setscope( &attr, PTHREAD_SCOPE_SYSTEM );
+#  endif
+         failure
+           = panic ? 1 : pthread_create( &thread->thr, &attr,
+                                         Perl_ithread_run, (void *)thread);
 #endif
        }
 #endif
        known_threads++;
+       if (
+#ifdef WIN32
+           thread->handle == NULL
+#else
+           failure
+#endif
+           ) {
+         MUTEX_UNLOCK(&create_destruct_mutex);
+         sv_2mortal(params);
+         Perl_ithread_destruct(aTHX_ thread, "create failed");
+#ifndef WIN32
+         if (panic)
+           Perl_croak(aTHX_ panic);
+#endif
+         return &PL_sv_undef;
+       }
        active_threads++;
        MUTEX_UNLOCK(&create_destruct_mutex);
        sv_2mortal(params);
+
        return ithread_to_SV(aTHX_ obj, thread, classname, FALSE);
 }
 
 SV*
 Perl_ithread_self (pTHX_ SV *obj, char* Class)
 {
-    ithread *thread;
-    PERL_THREAD_GETSPECIFIC(self_key,thread);
-    return ithread_to_SV(aTHX_ obj, thread, Class, TRUE);
+   ithread *thread = Perl_ithread_get(aTHX);
+   if (thread)
+       return ithread_to_SV(aTHX_ obj, thread, Class, TRUE);
+   else
+       Perl_croak(aTHX_ "panic: cannot find thread data");
+   return NULL; /* silence compiler warning */
 }
 
 /*
@@ -473,14 +578,12 @@ Perl_ithread_self (pTHX_ SV *obj, char* Class)
 void
 Perl_ithread_CLONE(pTHX_ SV *obj)
 {
- if (SvROK(obj))
-  {
-   ithread *thread = SV_to_ithread(aTHX_ obj);
-  }
- else
-  {
-   Perl_warn(aTHX_ "CLONE %" SVf,obj);
-  }
+    if (SvROK(obj)) {
+       ithread *thread = SV_to_ithread(aTHX_ obj);
+    }
+    else if (ckWARN_d(WARN_THREADS)) {
+       Perl_warn(aTHX_ "CLONE %" SVf,obj);
+    }
 }
 
 AV*
@@ -506,6 +609,8 @@ Perl_ithread_join(pTHX_ SV *obj)
        MUTEX_UNLOCK(&thread->mutex);
 #ifdef WIN32
        waitcode = WaitForSingleObject(thread->handle, INFINITE);
+       CloseHandle(thread->handle);
+       thread->handle = 0;
 #else
        pthread_join(thread->thr,&retval);
 #endif
@@ -515,12 +620,17 @@ Perl_ithread_join(pTHX_ SV *obj)
        {
          ithread*        current_thread;
          AV* params = (AV*) SvRV(thread->params);      
+         PerlInterpreter *other_perl = thread->interp;
          CLONE_PARAMS clone_params;
          clone_params.stashes = newAV();
          clone_params.flags |= CLONEf_JOIN_IN;
          PL_ptr_table = ptr_table_new();
-         PERL_THREAD_GETSPECIFIC(self_key,current_thread);
-         PERL_THREAD_SETSPECIFIC(self_key,thread);
+         current_thread = Perl_ithread_get(aTHX);
+         Perl_ithread_set(aTHX_ thread);
+         /* ensure 'meaningful' addresses retain their meaning */
+         ptr_table_store(PL_ptr_table, &other_perl->Isv_undef, &PL_sv_undef);
+         ptr_table_store(PL_ptr_table, &other_perl->Isv_no, &PL_sv_no);
+         ptr_table_store(PL_ptr_table, &other_perl->Isv_yes, &PL_sv_yes);
 
 #if 0
          {
@@ -541,17 +651,18 @@ Perl_ithread_join(pTHX_ SV *obj)
            }
          }
 #endif
-         PERL_THREAD_SETSPECIFIC(self_key,current_thread);
+         Perl_ithread_set(aTHX_ current_thread);
          SvREFCNT_dec(clone_params.stashes);
          SvREFCNT_inc(retparam);
          ptr_table_free(PL_ptr_table);
          PL_ptr_table = NULL;
 
        }
-       /* We have finished with it */
+       /* We are finished with it */
        thread->state |= PERL_ITHR_JOINED;
+       S_ithread_clear(aTHX_ thread);
        MUTEX_UNLOCK(&thread->mutex);
-       sv_unmagic(SvRV(obj),PERL_MAGIC_shared_scalar);
+       
        return retparam;
     }
     return (AV*)NULL;
@@ -596,7 +707,7 @@ PPCODE:
   MUTEX_LOCK(&create_destruct_mutex);
   curr_thread = threads;
   if(curr_thread->tid != 0)    
-    PUSHs( sv_2mortal(ithread_to_SV(aTHX_ NULL, curr_thread, classname, TRUE)));
+    XPUSHs( sv_2mortal(ithread_to_SV(aTHX_ NULL, curr_thread, classname, TRUE)));
   while(curr_thread) {
     curr_thread = curr_thread->next;
     if(curr_thread == threads)
@@ -604,7 +715,7 @@ PPCODE:
     if(curr_thread->state & PERL_ITHR_DETACHED ||
        curr_thread->state & PERL_ITHR_JOINED)
          continue;
-     PUSHs( sv_2mortal(ithread_to_SV(aTHX_ NULL, curr_thread, classname, TRUE)));
+     XPUSHs( sv_2mortal(ithread_to_SV(aTHX_ NULL, curr_thread, classname, TRUE)));
   }    
   MUTEX_UNLOCK(&create_destruct_mutex);
 }
@@ -657,11 +768,15 @@ BOOT:
 #ifdef USE_ITHREADS
        ithread* thread;
        PL_perl_destruct_level = 2;
-       PERL_THREAD_ALLOC_SPECIFIC(self_key);
        MUTEX_INIT(&create_destruct_mutex);
        MUTEX_LOCK(&create_destruct_mutex);
        PL_threadhook = &Perl_ithread_hook;
-       thread  = PerlMemShared_malloc(sizeof(ithread));
+       thread  = (ithread *) PerlMemShared_malloc(sizeof(ithread));
+       if (!thread) {
+           PerlLIO_write(PerlIO_fileno(Perl_error_log),
+                         PL_no_mem, strlen(PL_no_mem));
+           my_exit(1);
+       }
        Zero(thread,1,ithread);
        PL_perl_destruct_level = 2;
        MUTEX_INIT(&thread->mutex);
@@ -669,18 +784,18 @@ BOOT:
        thread->next = thread;
         thread->prev = thread;
        thread->interp = aTHX;
-       thread->count  = 1;  /* imortal */
+       thread->count  = 1;  /* Immortal. */
        thread->tid = tid_counter++;
        known_threads++;
        active_threads++;
-       thread->state = 1;
+       thread->state = PERL_ITHR_DETACHED;
 #ifdef WIN32
        thread->thr = GetCurrentThreadId();
 #else
        thread->thr = pthread_self();
 #endif
 
-       PERL_THREAD_SETSPECIFIC(self_key,thread);
+       Perl_ithread_set(aTHX_ thread);
        MUTEX_UNLOCK(&create_destruct_mutex);
 #endif /* USE_ITHREADS */
 }