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      1 // Copyright 2009 The Go Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style
      3 // license that can be found in the LICENSE file.
      4 
      5 #include <sys/types.h>
      6 #include <pthread.h>
      7 #include <signal.h>
      8 #include <string.h>
      9 #include "libcgo.h"
     10 #include "libcgo_unix.h"
     11 
     12 static void* threadentry(void*);
     13 static void (*setg_gcc)(void*);
     14 
     15 void
     16 x_cgo_init(G *g, void (*setg)(void*))
     17 {
     18 	pthread_attr_t attr;
     19 	size_t size;
     20 
     21 	setg_gcc = setg;
     22 	pthread_attr_init(&attr);
     23 	pthread_attr_getstacksize(&attr, &size);
     24 	g->stacklo = (uintptr)&attr - size + 4096;
     25 	pthread_attr_destroy(&attr);
     26 }
     27 
     28 
     29 void
     30 _cgo_sys_thread_start(ThreadStart *ts)
     31 {
     32 	pthread_attr_t attr;
     33 	sigset_t ign, oset;
     34 	pthread_t p;
     35 	size_t size;
     36 	int err;
     37 
     38 	sigfillset(&ign);
     39 	pthread_sigmask(SIG_SETMASK, &ign, &oset);
     40 
     41 	pthread_attr_init(&attr);
     42 	pthread_attr_getstacksize(&attr, &size);
     43 	// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
     44 	ts->g->stackhi = size;
     45 	err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);
     46 
     47 	pthread_sigmask(SIG_SETMASK, &oset, nil);
     48 
     49 	if (err != 0) {
     50 		fprintf(stderr, "runtime/cgo: pthread_create failed: %s\n", strerror(err));
     51 		abort();
     52 	}
     53 }
     54 
     55 static void*
     56 threadentry(void *v)
     57 {
     58 	ThreadStart ts;
     59 	stack_t ss;
     60 
     61 	ts = *(ThreadStart*)v;
     62 	free(v);
     63 
     64 	/*
     65 	 * Set specific keys.
     66 	 */
     67 	setg_gcc((void*)ts.g);
     68 
     69 	// On NetBSD, a new thread inherits the signal stack of the
     70 	// creating thread. That confuses minit, so we remove that
     71 	// signal stack here before calling the regular mstart. It's
     72 	// a bit baroque to remove a signal stack here only to add one
     73 	// in minit, but it's a simple change that keeps NetBSD
     74 	// working like other OS's. At this point all signals are
     75 	// blocked, so there is no race.
     76 	memset(&ss, 0, sizeof ss);
     77 	ss.ss_flags = SS_DISABLE;
     78 	sigaltstack(&ss, nil);
     79 
     80 	crosscall_386(ts.fn);
     81 	return nil;
     82 }
     83