github.com/aloncn/graphics-go@v0.0.1/src/runtime/cgo/gcc_openbsd_386.c (about)

     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  // +build cgo
     6  
     7  #include <sys/types.h>
     8  #include <dlfcn.h>
     9  #include <errno.h>
    10  #include <pthread.h>
    11  #include <signal.h>
    12  #include <string.h>
    13  #include "libcgo.h"
    14  
    15  static void* threadentry(void*);
    16  static void (*setg_gcc)(void*);
    17  
    18  // TCB_SIZE is sizeof(struct thread_control_block),
    19  // as defined in /usr/src/lib/librthread/tcb.h
    20  #define TCB_SIZE (4 * sizeof(void *))
    21  #define TLS_SIZE (2 * sizeof(void *))
    22  
    23  void *__get_tcb(void);
    24  void __set_tcb(void *);
    25  
    26  static int (*sys_pthread_create)(pthread_t *thread, const pthread_attr_t *attr,
    27  	void *(*start_routine)(void *), void *arg);
    28  
    29  struct thread_args {
    30  	void *(*func)(void *);
    31  	void *arg;
    32  };
    33  
    34  static void
    35  tcb_fixup(int mainthread)
    36  {
    37  	void *newtcb, *oldtcb;
    38  
    39  	// The OpenBSD ld.so(1) does not currently support PT_TLS. As a result,
    40  	// we need to allocate our own TLS space while preserving the existing
    41  	// TCB that has been setup via librthread.
    42  
    43  	newtcb = malloc(TCB_SIZE + TLS_SIZE);
    44  	if(newtcb == NULL)
    45  		abort();
    46  
    47  	// The signal trampoline expects the TLS slots to be zeroed.
    48  	bzero(newtcb, TLS_SIZE);
    49  
    50  	oldtcb = __get_tcb();
    51  	bcopy(oldtcb, newtcb + TLS_SIZE, TCB_SIZE);
    52  	__set_tcb(newtcb + TLS_SIZE);
    53  
    54  	// NOTE(jsing, minux): we can't free oldtcb without causing double-free
    55  	// problem. so newtcb will be memory leaks. Get rid of this when OpenBSD
    56  	// has proper support for PT_TLS.
    57  }
    58  
    59  static void *
    60  thread_start_wrapper(void *arg)
    61  {
    62  	struct thread_args args = *(struct thread_args *)arg;
    63  
    64  	free(arg);
    65  	tcb_fixup(0);
    66  
    67  	return args.func(args.arg);
    68  }
    69  
    70  static void init_pthread_wrapper(void) {
    71  	void *handle;
    72  
    73  	// Locate symbol for the system pthread_create function.
    74  	handle = dlopen("libpthread.so", RTLD_LAZY);
    75  	if(handle == NULL) {
    76  		fprintf(stderr, "runtime/cgo: dlopen failed to load libpthread: %s\n", dlerror());
    77  		abort();
    78  	}
    79  	sys_pthread_create = dlsym(handle, "pthread_create");
    80  	if(sys_pthread_create == NULL) {
    81  		fprintf(stderr, "runtime/cgo: dlsym failed to find pthread_create: %s\n", dlerror());
    82  		abort();
    83  	}
    84  	dlclose(handle);
    85  }
    86  
    87  static pthread_once_t init_pthread_wrapper_once = PTHREAD_ONCE_INIT;
    88  
    89  int
    90  pthread_create(pthread_t *thread, const pthread_attr_t *attr,
    91  	void *(*start_routine)(void *), void *arg)
    92  {
    93  	struct thread_args *p;
    94  
    95  	// we must initialize our wrapper in pthread_create, because it is valid to call
    96  	// pthread_create in a static constructor, and in fact, our test for issue 9456
    97  	// does just that.
    98  	if(pthread_once(&init_pthread_wrapper_once, init_pthread_wrapper) != 0) {
    99  		fprintf(stderr, "runtime/cgo: failed to initialize pthread_create wrapper\n");
   100  		abort();
   101  	}
   102  
   103  	p = malloc(sizeof(*p));
   104  	if(p == NULL) {
   105  		errno = ENOMEM;
   106  		return -1;
   107  	}
   108  	p->func = start_routine;
   109  	p->arg = arg;
   110  
   111  	return sys_pthread_create(thread, attr, thread_start_wrapper, p);
   112  }
   113  
   114  void
   115  x_cgo_init(G *g, void (*setg)(void*))
   116  {
   117  	pthread_attr_t attr;
   118  	size_t size;
   119  
   120  	setg_gcc = setg;
   121  	pthread_attr_init(&attr);
   122  	pthread_attr_getstacksize(&attr, &size);
   123  	g->stacklo = (uintptr)&attr - size + 4096;
   124  	pthread_attr_destroy(&attr);
   125  
   126  	if(pthread_once(&init_pthread_wrapper_once, init_pthread_wrapper) != 0) {
   127  		fprintf(stderr, "runtime/cgo: failed to initialize pthread_create wrapper\n");
   128  		abort();
   129  	}
   130  
   131  	tcb_fixup(1);
   132  }
   133  
   134  
   135  void
   136  _cgo_sys_thread_start(ThreadStart *ts)
   137  {
   138  	pthread_attr_t attr;
   139  	sigset_t ign, oset;
   140  	pthread_t p;
   141  	size_t size;
   142  	int err;
   143  
   144  	sigfillset(&ign);
   145  	pthread_sigmask(SIG_SETMASK, &ign, &oset);
   146  
   147  	pthread_attr_init(&attr);
   148  	pthread_attr_getstacksize(&attr, &size);
   149  	// Leave stacklo=0 and set stackhi=size; mstack will do the rest.
   150  	ts->g->stackhi = size;
   151  	err = sys_pthread_create(&p, &attr, threadentry, ts);
   152  
   153  	pthread_sigmask(SIG_SETMASK, &oset, nil);
   154  
   155  	if (err != 0) {
   156  		fprintf(stderr, "runtime/cgo: pthread_create failed: %s\n", strerror(err));
   157  		abort();
   158  	}
   159  }
   160  
   161  static void*
   162  threadentry(void *v)
   163  {
   164  	ThreadStart ts;
   165  
   166  	tcb_fixup(0);
   167  
   168  	ts = *(ThreadStart*)v;
   169  	free(v);
   170  
   171  	/*
   172  	 * Set specific keys.
   173  	 */
   174  	setg_gcc((void*)ts.g);
   175  
   176  	crosscall_386(ts.fn);
   177  	return nil;
   178  }