1 // Copyright 2015 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 <pthread.h> 6 #include <signal.h> 7 #include <stdio.h> 8 #include <sys/limits.h> 9 #include "libcgo.h" 10 11 #define magic1 (0x23581321345589ULL) 12 13 // inittls allocates a thread-local storage slot for g. 14 // 15 // It finds the first available slot using pthread_key_create and uses 16 // it as the offset value for runtime.tlsg. 17 static void 18 inittls(void **tlsg, void **tlsbase) 19 { 20 pthread_key_t k; 21 int i, err; 22 23 err = pthread_key_create(&k, nil); 24 if(err != 0) { 25 fatalf("pthread_key_create failed: %d", err); 26 } 27 pthread_setspecific(k, (void*)magic1); 28 // If thread local slots are laid out as we expect, our magic word will 29 // be located at some low offset from tlsbase. However, just in case something went 30 // wrong, the search is limited to sensible offsets. PTHREAD_KEYS_MAX was the 31 // original limit, but issue 19472 made a higher limit necessary. 32 for (i=0; i<384; i++) { 33 if (*(tlsbase+i) == (void*)magic1) { 34 *tlsg = (void*)(i*sizeof(void *)); 35 pthread_setspecific(k, 0); 36 return; 37 } 38 } 39 fatalf("could not find pthread key"); 40 } 41 42 void (*x_cgo_inittls)(void **tlsg, void **tlsbase) = inittls; 43
