// Copyright 2015 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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#include <pthread.h>
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#include <signal.h>
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#include <stdio.h>
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#include <sys/limits.h>
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#include "libcgo.h"
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#define magic1 (0x23581321345589ULL)
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// inittls allocates a thread-local storage slot for g.
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//
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// It finds the first available slot using pthread_key_create and uses
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// it as the offset value for runtime.tlsg.
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static void
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inittls(void **tlsg, void **tlsbase)
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{
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pthread_key_t k;
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int i, err;
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err = pthread_key_create(&k, nil);
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if(err != 0) {
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fatalf("pthread_key_create failed: %d", err);
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}
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pthread_setspecific(k, (void*)magic1);
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// If thread local slots are laid out as we expect, our magic word will
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// be located at some low offset from tlsbase. However, just in case something went
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// wrong, the search is limited to sensible offsets. PTHREAD_KEYS_MAX was the
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// original limit, but issue 19472 made a higher limit necessary.
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for (i=0; i<384; i++) {
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if (*(tlsbase+i) == (void*)magic1) {
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*tlsg = (void*)(i*sizeof(void *));
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pthread_setspecific(k, 0);
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return;
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}
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}
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fatalf("could not find pthread key");
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}
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void (*x_cgo_inittls)(void **tlsg, void **tlsbase) = inittls;
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