github.com/ice-blockchain/go/src@v0.0.0-20240403114104-1564d284e521/runtime/cgo/gcc_android.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  #include <stdarg.h>
     6  #include <android/log.h>
     7  #include <pthread.h>
     8  #include <dlfcn.h>
     9  #include "libcgo.h"
    10  
    11  void
    12  fatalf(const char* format, ...)
    13  {
    14  	va_list ap;
    15  
    16  	// Write to both stderr and logcat.
    17  	//
    18  	// When running from an .apk, /dev/stderr and /dev/stdout
    19  	// redirect to /dev/null. And when running a test binary
    20  	// via adb shell, it's easy to miss logcat.
    21  
    22  	fprintf(stderr, "runtime/cgo: ");
    23  	va_start(ap, format);
    24  	vfprintf(stderr, format, ap);
    25  	va_end(ap);
    26  	fprintf(stderr, "\n");
    27  
    28  	va_start(ap, format);
    29  	__android_log_vprint(ANDROID_LOG_FATAL, "runtime/cgo", format, ap);
    30  	va_end(ap);
    31  
    32  	abort();
    33  }
    34  
    35  // Truncated to a different magic value on 32-bit; that's ok.
    36  #define magic1 (0x23581321345589ULL)
    37  
    38  // From https://android.googlesource.com/platform/bionic/+/refs/heads/android10-tests-release/libc/private/bionic_asm_tls.h#69.
    39  #define TLS_SLOT_APP 2
    40  
    41  // inittls allocates a thread-local storage slot for g.
    42  //
    43  // It finds the first available slot using pthread_key_create and uses
    44  // it as the offset value for runtime.tls_g.
    45  static void
    46  inittls(void **tlsg, void **tlsbase)
    47  {
    48  	pthread_key_t k;
    49  	int i, err;
    50  	void *handle, *get_ver, *off;
    51  
    52  	// Check for Android Q where we can use the free TLS_SLOT_APP slot.
    53  	handle = dlopen("libc.so", RTLD_LAZY);
    54  	if (handle == NULL) {
    55  		fatalf("inittls: failed to dlopen main program");
    56  		return;
    57  	}
    58  	// android_get_device_api_level is introduced in Android Q, so its mere presence
    59  	// is enough.
    60  	get_ver = dlsym(handle, "android_get_device_api_level");
    61  	dlclose(handle);
    62  	if (get_ver != NULL) {
    63  		off = (void *)(TLS_SLOT_APP*sizeof(void *));
    64  		// tlsg is initialized to Q's free TLS slot. Verify it while we're here.
    65  		if (*tlsg != off) {
    66  			fatalf("tlsg offset wrong, got %ld want %ld\n", *tlsg, off);
    67  		}
    68  		return;
    69  	}
    70  
    71  	err = pthread_key_create(&k, nil);
    72  	if(err != 0) {
    73  		fatalf("pthread_key_create failed: %d", err);
    74  	}
    75  	pthread_setspecific(k, (void*)magic1);
    76  	// If thread local slots are laid out as we expect, our magic word will
    77  	// be located at some low offset from tlsbase. However, just in case something went
    78  	// wrong, the search is limited to sensible offsets. PTHREAD_KEYS_MAX was the
    79  	// original limit, but issue 19472 made a higher limit necessary.
    80  	for (i=0; i<384; i++) {
    81  		if (*(tlsbase+i) == (void*)magic1) {
    82  			*tlsg = (void*)(i*sizeof(void *));
    83  			pthread_setspecific(k, 0);
    84  			return;
    85  		}
    86  	}
    87  	fatalf("inittls: could not find pthread key");
    88  }
    89  
    90  void (*x_cgo_inittls)(void **tlsg, void **tlsbase) = inittls;