github.com/c12o16h1/go/src@v0.0.0-20200114212001-5a151c0f00ed/runtime/cgo/gcc_netbsd_arm64.c (about)

     1  // Copyright 2019 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  
    14  static void (*setg_gcc)(void*);
    15  
    16  void
    17  x_cgo_init(G *g, void (*setg)(void*))
    18  {
    19  	pthread_attr_t attr;
    20  	size_t size;
    21  
    22  	setg_gcc = setg;
    23  	pthread_attr_init(&attr);
    24  	pthread_attr_getstacksize(&attr, &size);
    25  	g->stacklo = (uintptr)&attr - size + 4096;
    26  	pthread_attr_destroy(&attr);
    27  }
    28  
    29  
    30  void
    31  _cgo_sys_thread_start(ThreadStart *ts)
    32  {
    33  	pthread_attr_t attr;
    34  	sigset_t ign, oset;
    35  	pthread_t p;
    36  	size_t size;
    37  	int err;
    38  
    39  	sigfillset(&ign);
    40  	pthread_sigmask(SIG_SETMASK, &ign, &oset);
    41  
    42  	pthread_attr_init(&attr);
    43  	pthread_attr_getstacksize(&attr, &size);
    44  	// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
    45  	ts->g->stackhi = size;
    46  	err = _cgo_try_pthread_create(&p, &attr, threadentry, ts);
    47  
    48  	pthread_sigmask(SIG_SETMASK, &oset, nil);
    49  
    50  	if (err != 0) {
    51  		fprintf(stderr, "runtime/cgo: pthread_create failed: %s\n", strerror(err));
    52  		abort();
    53  	}
    54  }
    55  
    56  static void*
    57  threadentry(void *v)
    58  {
    59  	ThreadStart ts;
    60  	stack_t ss;
    61  
    62  	ts = *(ThreadStart*)v;
    63  	free(v);
    64  
    65  	// On NetBSD, a new thread inherits the signal stack of the
    66  	// creating thread. That confuses minit, so we remove that
    67  	// signal stack here before calling the regular mstart. It's
    68  	// a bit baroque to remove a signal stack here only to add one
    69  	// in minit, but it's a simple change that keeps NetBSD
    70  	// working like other OS's. At this point all signals are
    71  	// blocked, so there is no race.
    72  	memset(&ss, 0, sizeof ss);
    73  	ss.ss_flags = SS_DISABLE;
    74  	sigaltstack(&ss, nil);
    75  
    76  	crosscall1(ts.fn, setg_gcc, (void*)ts.g);
    77  	return nil;
    78  }