github.com/aloncn/graphics-go@v0.0.1/src/runtime/cgo/gcc_darwin_arm64.c (about)

     1  // Copyright 2014 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 <limits.h>
     8  #include <pthread.h>
     9  #include <signal.h>
    10  #include <string.h> /* for strerror */
    11  #include <sys/param.h>
    12  #include <unistd.h>
    13  #include <stdlib.h>
    14  
    15  #include "libcgo.h"
    16  
    17  #include <CoreFoundation/CFBundle.h>
    18  #include <CoreFoundation/CFString.h>
    19  
    20  #define magic (0xc476c475c47957UL)
    21  
    22  // inittls allocates a thread-local storage slot for g.
    23  //
    24  // It finds the first available slot using pthread_key_create and uses
    25  // it as the offset value for runtime.tlsg.
    26  static void
    27  inittls(void **tlsg, void **tlsbase)
    28  {
    29  	pthread_key_t k;
    30  	int i, err;
    31  
    32  	err = pthread_key_create(&k, nil);
    33  	if(err != 0) {
    34  		fprintf(stderr, "runtime/cgo: pthread_key_create failed: %d\n", err);
    35  		abort();
    36  	}
    37  	//fprintf(stderr, "runtime/cgo: k = %d, tlsbase = %p\n", (int)k, tlsbase); // debug
    38  	pthread_setspecific(k, (void*)magic);
    39  	// The first key should be at 257.
    40  	for (i=0; i<PTHREAD_KEYS_MAX; i++) {
    41  		if (*(tlsbase+i) == (void*)magic) {
    42  			*tlsg = (void*)(i*sizeof(void *));
    43  			pthread_setspecific(k, 0);
    44  			return;
    45  		}
    46  	}
    47  	fprintf(stderr, "runtime/cgo: could not find pthread key.\n");
    48  	abort();
    49  }
    50  
    51  static void *threadentry(void*);
    52  void (*setg_gcc)(void*);
    53  
    54  void
    55  _cgo_sys_thread_start(ThreadStart *ts)
    56  {
    57  	pthread_attr_t attr;
    58  	sigset_t ign, oset;
    59  	pthread_t p;
    60  	size_t size;
    61  	int err;
    62  
    63  	//fprintf(stderr, "runtime/cgo: _cgo_sys_thread_start: fn=%p, g=%p\n", ts->fn, ts->g); // debug
    64  	sigfillset(&ign);
    65  	pthread_sigmask(SIG_SETMASK, &ign, &oset);
    66  
    67  	pthread_attr_init(&attr);
    68  	size = 0;
    69  	pthread_attr_getstacksize(&attr, &size);
    70  	// Leave stacklo=0 and set stackhi=size; mstack will do the rest.
    71  	ts->g->stackhi = size;
    72  	err = pthread_create(&p, &attr, threadentry, ts);
    73  
    74  	pthread_sigmask(SIG_SETMASK, &oset, nil);
    75  
    76  	if (err != 0) {
    77  		fprintf(stderr, "runtime/cgo: pthread_create failed: %s\n", strerror(err));
    78  		abort();
    79  	}
    80  }
    81  
    82  extern void crosscall1(void (*fn)(void), void (*setg_gcc)(void*), void *g);
    83  static void*
    84  threadentry(void *v)
    85  {
    86  	ThreadStart ts;
    87  
    88  	ts = *(ThreadStart*)v;
    89  	free(v);
    90  
    91  	darwin_arm_init_thread_exception_port();
    92  
    93  	crosscall1(ts.fn, setg_gcc, (void*)ts.g);
    94  	return nil;
    95  }
    96  
    97  // init_working_dir sets the current working directory to the app root.
    98  // By default darwin/arm processes start in "/".
    99  static void
   100  init_working_dir()
   101  {
   102  	CFBundleRef bundle = CFBundleGetMainBundle();
   103  	if (bundle == NULL) {
   104  		fprintf(stderr, "runtime/cgo: no main bundle\n");
   105  		return;
   106  	}
   107  	CFURLRef url_ref = CFBundleCopyResourceURL(bundle, CFSTR("Info"), CFSTR("plist"), NULL);
   108  	if (url_ref == NULL) {
   109  		fprintf(stderr, "runtime/cgo: no Info.plist URL\n");
   110  		return;
   111  	}
   112  	CFStringRef url_str_ref = CFURLGetString(url_ref);
   113  	char url[MAXPATHLEN];
   114          if (!CFStringGetCString(url_str_ref, url, sizeof(url), kCFStringEncodingUTF8)) {
   115  		fprintf(stderr, "runtime/cgo: cannot get URL string\n");
   116  		return;
   117  	}
   118  
   119  	// url is of the form "file:///path/to/Info.plist".
   120  	// strip it down to the working directory "/path/to".
   121  	int url_len = strlen(url);
   122  	if (url_len < sizeof("file://")+sizeof("/Info.plist")) {
   123  		fprintf(stderr, "runtime/cgo: bad URL: %s\n", url);
   124  		return;
   125  	}
   126  	url[url_len-sizeof("/Info.plist")+1] = 0;
   127  	char *dir = &url[0] + sizeof("file://")-1;
   128  
   129  	if (chdir(dir) != 0) {
   130  		fprintf(stderr, "runtime/cgo: chdir(%s) failed\n", dir);
   131  	}
   132  
   133  	// No-op to set a breakpoint on, immediately after the real chdir.
   134  	// Gives the test harness in go_darwin_arm_exec (which uses lldb) a
   135  	// chance to move the working directory.
   136  	getwd(dir);
   137  }
   138  
   139  void
   140  x_cgo_init(G *g, void (*setg)(void*), void **tlsg, void **tlsbase)
   141  {
   142  	pthread_attr_t attr;
   143  	size_t size;
   144  
   145  	//fprintf(stderr, "x_cgo_init = %p\n", &x_cgo_init); // aid debugging in presence of ASLR
   146  	setg_gcc = setg;
   147  	pthread_attr_init(&attr);
   148  	pthread_attr_getstacksize(&attr, &size);
   149  	g->stacklo = (uintptr)&attr - size + 4096;
   150  	pthread_attr_destroy(&attr);
   151  
   152  	// yes, tlsbase from mrs might not be correctly aligned.
   153  	inittls(tlsg, (void**)((uintptr)tlsbase & ~7));
   154  
   155  	darwin_arm_init_mach_exception_handler();
   156  	darwin_arm_init_thread_exception_port();
   157  
   158  	init_working_dir();
   159  }